granicus.if.org Git - postgresql/blob - src/backend/postmaster/postmaster.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * postmaster.c
   4  *        This program acts as a clearing house for requests to the
   5  *        POSTGRES system.      Frontend programs send a startup message
   6  *        to the Postmaster and the postmaster uses the info in the
   7  *        message to setup a backend process.
   8  *
   9  *        The postmaster also manages system-wide operations such as
  10  *        startup, shutdown, and periodic checkpoints.  The postmaster
  11  *        itself doesn't do those operations, mind you --- it just forks
  12  *        off a subprocess to do them at the right times.  It also takes
  13  *        care of resetting the system if a backend crashes.
  14  *
  15  *        The postmaster process creates the shared memory and semaphore
  16  *        pools during startup, but as a rule does not touch them itself.
  17  *        In particular, it is not a member of the PGPROC array of backends
  18  *        and so it cannot participate in lock-manager operations.      Keeping
  19  *        the postmaster away from shared memory operations makes it simpler
  20  *        and more reliable.  The postmaster is almost always able to recover
  21  *        from crashes of individual backends by resetting shared memory;
  22  *        if it did much with shared memory then it would be prone to crashing
  23  *        along with the backends.
  24  *
  25  *        When a request message is received, we now fork() immediately.
  26  *        The child process performs authentication of the request, and
  27  *        then becomes a backend if successful.  This allows the auth code
  28  *        to be written in a simple single-threaded style (as opposed to the
  29  *        crufty "poor man's multitasking" code that used to be needed).
  30  *        More importantly, it ensures that blockages in non-multithreaded
  31  *        libraries like SSL or PAM cannot cause denial of service to other
  32  *        clients.
  33  *
  34  *
  35  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  36  * Portions Copyright (c) 1994, Regents of the University of California
  37  *
  38  *
  39  * IDENTIFICATION
  40  *        $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.382 2004/05/06 19:23:25 momjian Exp $
  41  *
  42  * NOTES
  43  *
  44  * Initialization:
  45  *              The Postmaster sets up a few shared memory data structures
  46  *              for the backends.  It should at the very least initialize the
  47  *              lock manager.
  48  *
  49  * Synchronization:
  50  *              The Postmaster shares memory with the backends but should avoid
  51  *              touching shared memory, so as not to become stuck if a crashing
  52  *              backend screws up locks or shared memory.  Likewise, the Postmaster
  53  *              should never block on messages from frontend clients.
  54  *
  55  * Garbage Collection:
  56  *              The Postmaster cleans up after backends if they have an emergency
  57  *              exit and/or core dump.
  58  *
  59  *-------------------------------------------------------------------------
  60  */
  61
  62 #include "postgres.h"
  63
  64 #include <unistd.h>
  65 #include <signal.h>
  66 #include <sys/wait.h>
  67 #include <ctype.h>
  68 #include <sys/stat.h>
  69 #include <sys/time.h>
  70 #include <sys/socket.h>
  71 #include <errno.h>
  72 #include <fcntl.h>
  73 #include <time.h>
  74 #include <sys/param.h>
  75 #include <netinet/in.h>
  76 #include <arpa/inet.h>
  77 #include <netdb.h>
  78 #include <limits.h>
  79
  80 #ifdef HAVE_SYS_SELECT_H
  81 #include <sys/select.h>
  82 #endif
  83
  84 #ifdef HAVE_GETOPT_H
  85 #include <getopt.h>
  86 #endif
  87
  88 #ifdef USE_RENDEZVOUS
  89 #include <DNSServiceDiscovery/DNSServiceDiscovery.h>
  90 #endif
  91
  92 #include "catalog/pg_database.h"
  93 #include "commands/async.h"
  94 #include "lib/dllist.h"
  95 #include "libpq/auth.h"
  96 #include "libpq/crypt.h"
  97 #include "libpq/libpq.h"
  98 #include "libpq/pqcomm.h"
  99 #include "libpq/pqsignal.h"
 100 #include "miscadmin.h"
 101 #include "nodes/nodes.h"
 102 #include "storage/fd.h"
 103 #include "storage/ipc.h"
 104 #include "storage/pg_shmem.h"
 105 #include "storage/pmsignal.h"
 106 #include "storage/proc.h"
 107 #include "storage/bufmgr.h"
 108 #include "access/xlog.h"
 109 #include "tcop/tcopprot.h"
 110 #include "utils/guc.h"
 111 #include "utils/memutils.h"
 112 #include "utils/ps_status.h"
 113 #include "bootstrap/bootstrap.h"
 114 #include "pgstat.h"
 115
 116
 117 #define INVALID_SOCK    (-1)
 118
 119 #ifdef HAVE_SIGPROCMASK
 120 sigset_t        UnBlockSig,
 121                         BlockSig,
 122                         AuthBlockSig;
 123
 124 #else
 125 int                     UnBlockSig,
 126                         BlockSig,
 127                         AuthBlockSig;
 128 #endif
 129
 130 /*
 131  * List of active backends (or child processes anyway; we don't actually
 132  * know whether a given child has become a backend or is still in the
 133  * authorization phase).  This is used mainly to keep track of how many
 134  * children we have and send them appropriate signals when necessary.
 135  */
 136 typedef struct bkend
 137 {
 138         pid_t           pid;                    /* process id of backend */
 139         long            cancel_key;             /* cancel key for cancels for this backend */
 140 } Backend;
 141
 142 static Dllist *BackendList;
 143
 144 #ifdef EXEC_BACKEND
 145 #define NUM_BACKENDARRAY_ELEMS (2*MaxBackends)
 146 static Backend *ShmemBackendArray;
 147 #endif
 148
 149 /* The socket number we are listening for connections on */
 150 int                     PostPortNumber;
 151 char       *UnixSocketDir;
 152 char       *ListenAddresses;
 153
 154 /*
 155  * MaxBackends is the limit on the number of backends we can start.
 156  * Note that a larger MaxBackends value will increase the size of the
 157  * shared memory area as well as cause the postmaster to grab more
 158  * kernel semaphores, even if you never actually use that many
 159  * backends.
 160  */
 161 int                     MaxBackends;
 162
 163 /*
 164  * ReservedBackends is the number of backends reserved for superuser use.
 165  * This number is taken out of the pool size given by MaxBackends so
 166  * number of backend slots available to non-superusers is
 167  * (MaxBackends - ReservedBackends).  Note what this really means is
 168  * "if there are <= ReservedBackends connections available, only superusers
 169  * can make new connections" --- pre-existing superuser connections don't
 170  * count against the limit.
 171  */
 172 int                     ReservedBackends;
 173
 174
 175 static char *progname = NULL;
 176
 177 /* The socket(s) we're listening to. */
 178 #define MAXLISTEN       10
 179 static int      ListenSocket[MAXLISTEN];
 180
 181 /* Used to reduce macros tests */
 182 #ifdef EXEC_BACKEND
 183 const bool      ExecBackend = true;
 184
 185 #else
 186 const bool      ExecBackend = false;
 187 #endif
 188
 189 /*
 190  * Set by the -o option
 191  */
 192 static char ExtraOptions[MAXPGPATH];
 193
 194 /*
 195  * These globals control the behavior of the postmaster in case some
 196  * backend dumps core.  Normally, it kills all peers of the dead backend
 197  * and reinitializes shared memory.  By specifying -s or -n, we can have
 198  * the postmaster stop (rather than kill) peers and not reinitialize
 199  * shared data structures.
 200  */
 201 static bool Reinit = true;
 202 static int      SendStop = false;
 203
 204 /* still more option variables */
 205 bool            EnableSSL = false;
 206 bool            SilentMode = false; /* silent mode (-S) */
 207
 208 int                     PreAuthDelay = 0;
 209 int                     AuthenticationTimeout = 60;
 210 int                     CheckPointTimeout = 300;
 211 int                     CheckPointWarning = 30;
 212 time_t          LastSignalledCheckpoint = 0;
 213
 214 bool            log_hostname;           /* for ps display and logging */
 215 bool            Log_connections = false;
 216 bool            Db_user_namespace = false;
 217
 218 char       *rendezvous_name;
 219
 220 /* list of library:init-function to be preloaded */
 221 char       *preload_libraries_string = NULL;
 222
 223 /* Startup/shutdown state */
 224 static pid_t StartupPID = 0,
 225                         ShutdownPID = 0,
 226                         CheckPointPID = 0,
 227                         BgWriterPID = 0;
 228 static time_t checkpointed = 0;
 229
 230 #define                 NoShutdown              0
 231 #define                 SmartShutdown   1
 232 #define                 FastShutdown    2
 233
 234 static int      Shutdown = NoShutdown;
 235
 236 static bool FatalError = false; /* T if recovering from backend crash */
 237
 238 bool            ClientAuthInProgress = false;           /* T during new-client
 239                                                                                                  * authentication */
 240
 241 /*
 242  * State for assigning random salts and cancel keys.
 243  * Also, the global MyCancelKey passes the cancel key assigned to a given
 244  * backend from the postmaster to that backend (via fork).
 245  */
 246
 247 static unsigned int random_seed = 0;
 248
 249 static int      debug_flag = 0;
 250
 251 extern char *optarg;
 252 extern int      optind,
 253                         opterr;
 254
 255 #ifdef HAVE_INT_OPTRESET
 256 extern int      optreset;
 257 #endif
 258
 259 /*
 260  * postmaster.c - function prototypes
 261  */
 262 static void pmdaemonize(int argc, char *argv[]);
 263 static Port *ConnCreate(int serverFd);
 264 static void ConnFree(Port *port);
 265 static void reset_shared(unsigned short port);
 266 static void SIGHUP_handler(SIGNAL_ARGS);
 267 static void pmdie(SIGNAL_ARGS);
 268 static void reaper(SIGNAL_ARGS);
 269 static void sigusr1_handler(SIGNAL_ARGS);
 270 static void dummy_handler(SIGNAL_ARGS);
 271 static void CleanupProc(int pid, int exitstatus);
 272 static void LogChildExit(int lev, const char *procname,
 273                          int pid, int exitstatus);
 274 static void BackendInit(Port *port);
 275 static int  BackendRun(Port *port);
 276 static void ExitPostmaster(int status);
 277 static void usage(const char *);
 278 static int      ServerLoop(void);
 279 static int      BackendStartup(Port *port);
 280 static int      ProcessStartupPacket(Port *port, bool SSLdone);
 281 static void processCancelRequest(Port *port, void *pkt);
 282 static int      initMasks(fd_set *rmask);
 283 static void report_fork_failure_to_client(Port *port, int errnum);
 284 static enum CAC_state canAcceptConnections(void);
 285 static long PostmasterRandom(void);
 286 static void RandomSalt(char *cryptSalt, char *md5Salt);
 287 static void SignalChildren(int signal);
 288 static int      CountChildren(void);
 289 static bool CreateOptsFile(int argc, char *argv[]);
 290 NON_EXEC_STATIC void SSDataBaseInit(int xlop);
 291 static pid_t SSDataBase(int xlop);
 292 static void
 293 postmaster_error(const char *fmt,...)
 294 /* This lets gcc check the format string for consistency. */
 295 __attribute__((format(printf, 1, 2)));
 296
 297 #ifdef EXEC_BACKEND
 298 #ifdef WIN32
 299 pid_t win32_forkexec(const char* path, char *argv[]);
 300
 301 static void  win32_AddChild(pid_t pid, HANDLE handle);
 302 static void  win32_RemoveChild(pid_t pid);
 303 static pid_t win32_waitpid(int *exitstatus);
 304 static DWORD WINAPI win32_sigchld_waiter(LPVOID param);
 305
 306 static pid_t  *win32_childPIDArray;
 307 static HANDLE *win32_childHNDArray;
 308 static unsigned long win32_numChildren = 0;
 309 #endif
 310
 311 static pid_t Backend_forkexec(Port *port);
 312
 313 static unsigned long tmpBackendFileNum = 0;
 314 void read_backend_variables(unsigned long id, Port *port);
 315 static bool write_backend_variables(Port *port);
 316
 317 static void     ShmemBackendArrayAdd(Backend *bn);
 318 static void ShmemBackendArrayRemove(pid_t pid);
 319 #endif
 320
 321 #define StartupDataBase()               SSDataBase(BS_XLOG_STARTUP)
 322 #define CheckPointDataBase()    SSDataBase(BS_XLOG_CHECKPOINT)
 323 #define StartBackgroundWriter() SSDataBase(BS_XLOG_BGWRITER)
 324 #define ShutdownDataBase()              SSDataBase(BS_XLOG_SHUTDOWN)
 325
 326
 327 static void
 328 checkDataDir(const char *checkdir)
 329 {
 330         char            path[MAXPGPATH];
 331         FILE       *fp;
 332         struct stat stat_buf;
 333
 334         if (checkdir == NULL)
 335         {
 336                 fprintf(stderr,
 337                                 gettext("%s does not know where to find the database system data.\n"
 338                                                 "You must specify the directory that contains the database system\n"
 339                                                 "either by specifying the -D invocation option or by setting the\n"
 340                                                 "PGDATA environment variable.\n"),
 341                                 progname);
 342                 ExitPostmaster(2);
 343         }
 344
 345         if (stat(checkdir, &stat_buf) == -1)
 346         {
 347                 if (errno == ENOENT)
 348                         ereport(FATAL,
 349                                         (errcode_for_file_access(),
 350                                          errmsg("data directory \"%s\" does not exist",
 351                                                         checkdir)));
 352                 else
 353                         ereport(FATAL,
 354                                         (errcode_for_file_access(),
 355                          errmsg("could not read permissions of directory \"%s\": %m",
 356                                         checkdir)));
 357         }
 358
 359         /*
 360          * Check if the directory has group or world access.  If so, reject.
 361          *
 362          * XXX temporarily suppress check when on Windows, because there may not
 363          * be proper support for Unix-y file permissions.  Need to think of a
 364          * reasonable check to apply on Windows.
 365          */
 366 #if !defined(__CYGWIN__) && !defined(WIN32)
 367         if (stat_buf.st_mode & (S_IRWXG | S_IRWXO))
 368                 ereport(FATAL,
 369                                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
 370                                  errmsg("data directory \"%s\" has group or world access",
 371                                                 checkdir),
 372                                  errdetail("Permissions should be u=rwx (0700).")));
 373 #endif
 374
 375         /* Look for PG_VERSION before looking for pg_control */
 376         ValidatePgVersion(checkdir);
 377
 378         snprintf(path, sizeof(path), "%s/global/pg_control", checkdir);
 379
 380         fp = AllocateFile(path, PG_BINARY_R);
 381         if (fp == NULL)
 382         {
 383                 fprintf(stderr,
 384                                 gettext("%s: could not find the database system\n"
 385                                                 "Expected to find it in the directory \"%s\",\n"
 386                                                 "but could not open file \"%s\": %s\n"),
 387                                 progname, checkdir, path, strerror(errno));
 388                 ExitPostmaster(2);
 389         }
 390         FreeFile(fp);
 391 }
 392
 393
 394 #ifdef USE_RENDEZVOUS
 395
 396 /* reg_reply -- empty callback function for DNSServiceRegistrationCreate() */
 397 static void
 398 reg_reply(DNSServiceRegistrationReplyErrorType errorCode, void *context)
 399 {
 400
 401 }
 402 #endif
 403
 404 int
 405 PostmasterMain(int argc, char *argv[])
 406 {
 407         int                     opt;
 408         int                     status;
 409         char            original_extraoptions[MAXPGPATH];
 410         char       *potential_DataDir = NULL;
 411         int                     i;
 412
 413         *original_extraoptions = '\0';
 414
 415         progname = argv[0];
 416
 417         IsPostmasterEnvironment = true;
 418
 419         /*
 420          * Catch standard options before doing much else.  This even works on
 421          * systems without getopt_long.
 422          */
 423         if (argc > 1)
 424         {
 425                 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
 426                 {
 427                         usage(progname);
 428                         ExitPostmaster(0);
 429                 }
 430                 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
 431                 {
 432                         puts("postmaster (PostgreSQL) " PG_VERSION);
 433                         ExitPostmaster(0);
 434                 }
 435         }
 436
 437         /*
 438          * for security, no dir or file created can be group or other
 439          * accessible
 440          */
 441         umask((mode_t) 0077);
 442
 443         MyProcPid = PostmasterPid = getpid();
 444
 445         /*
 446          * Fire up essential subsystems: memory management
 447          */
 448         MemoryContextInit();
 449
 450         /*
 451          * By default, palloc() requests in the postmaster will be allocated
 452          * in the PostmasterContext, which is space that can be recycled by
 453          * backends.  Allocated data that needs to be available to backends
 454          * should be allocated in TopMemoryContext.
 455          */
 456         PostmasterContext = AllocSetContextCreate(TopMemoryContext,
 457                                                                                           "Postmaster",
 458                                                                                           ALLOCSET_DEFAULT_MINSIZE,
 459                                                                                           ALLOCSET_DEFAULT_INITSIZE,
 460                                                                                           ALLOCSET_DEFAULT_MAXSIZE);
 461         MemoryContextSwitchTo(PostmasterContext);
 462
 463         IgnoreSystemIndexes(false);
 464
 465         /*
 466          * Options setup
 467          */
 468         InitializeGUCOptions();
 469
 470         potential_DataDir = getenv("PGDATA");           /* default value */
 471
 472         opterr = 1;
 473
 474         while ((opt = getopt(argc, argv, "A:a:B:b:c:D:d:Fh:ik:lm:MN:no:p:Ss-:")) != -1)
 475         {
 476                 switch (opt)
 477                 {
 478                         case 'A':
 479 #ifdef USE_ASSERT_CHECKING
 480                                 SetConfigOption("debug_assertions", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 481 #else
 482                                 postmaster_error("assert checking is not compiled in");
 483 #endif
 484                                 break;
 485                         case 'a':
 486                                 /* Can no longer set authentication method. */
 487                                 break;
 488                         case 'B':
 489                                 SetConfigOption("shared_buffers", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 490                                 break;
 491                         case 'b':
 492                                 /* Can no longer set the backend executable file to use. */
 493                                 break;
 494                         case 'D':
 495                                 potential_DataDir = optarg;
 496                                 break;
 497                         case 'd':
 498                                 {
 499                                         /* Turn on debugging for the postmaster. */
 500                                         char       *debugstr = palloc(strlen("debug") + strlen(optarg) + 1);
 501
 502                                         sprintf(debugstr, "debug%s", optarg);
 503                                         SetConfigOption("log_min_messages", debugstr,
 504                                                                         PGC_POSTMASTER, PGC_S_ARGV);
 505                                         pfree(debugstr);
 506                                         debug_flag = atoi(optarg);
 507                                         break;
 508                                 }
 509                         case 'F':
 510                                 SetConfigOption("fsync", "false", PGC_POSTMASTER, PGC_S_ARGV);
 511                                 break;
 512                         case 'h':
 513                                 SetConfigOption("listen_addresses", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 514                                 break;
 515                         case 'i':
 516                                 SetConfigOption("listen_addresses", "*", PGC_POSTMASTER, PGC_S_ARGV);
 517                                 break;
 518                         case 'k':
 519                                 SetConfigOption("unix_socket_directory", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 520                                 break;
 521 #ifdef USE_SSL
 522                         case 'l':
 523                                 SetConfigOption("ssl", "true", PGC_POSTMASTER, PGC_S_ARGV);
 524                                 break;
 525 #endif
 526                         case 'm':
 527                                 /* Multiplexed backends no longer supported. */
 528                                 break;
 529                         case 'M':
 530
 531                                 /*
 532                                  * ignore this flag.  This may be passed in because the
 533                                  * program was run as 'postgres -M' instead of
 534                                  * 'postmaster'
 535                                  */
 536                                 break;
 537                         case 'N':
 538                                 /* The max number of backends to start. */
 539                                 SetConfigOption("max_connections", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 540                                 break;
 541                         case 'n':
 542                                 /* Don't reinit shared mem after abnormal exit */
 543                                 Reinit = false;
 544                                 break;
 545                         case 'o':
 546
 547                                 /*
 548                                  * Other options to pass to the backend on the command
 549                                  * line -- useful only for debugging.
 550                                  */
 551                                 strcat(ExtraOptions, " ");
 552                                 strcat(ExtraOptions, optarg);
 553                                 strcpy(original_extraoptions, optarg);
 554                                 break;
 555                         case 'p':
 556                                 SetConfigOption("port", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 557                                 break;
 558                         case 'S':
 559
 560                                 /*
 561                                  * Start in 'S'ilent mode (disassociate from controlling
 562                                  * tty). You may also think of this as 'S'ysV mode since
 563                                  * it's most badly needed on SysV-derived systems like
 564                                  * SVR4 and HP-UX.
 565                                  */
 566                                 SetConfigOption("silent_mode", "true", PGC_POSTMASTER, PGC_S_ARGV);
 567                                 break;
 568                         case 's':
 569
 570                                 /*
 571                                  * In the event that some backend dumps core, send
 572                                  * SIGSTOP, rather than SIGQUIT, to all its peers.      This
 573                                  * lets the wily post_hacker collect core dumps from
 574                                  * everyone.
 575                                  */
 576                                 SendStop = true;
 577                                 break;
 578                         case 'c':
 579                         case '-':
 580                                 {
 581                                         char       *name,
 582                                                            *value;
 583
 584                                         ParseLongOption(optarg, &name, &value);
 585                                         if (!value)
 586                                         {
 587                                                 if (opt == '-')
 588                                                         ereport(ERROR,
 589                                                                         (errcode(ERRCODE_SYNTAX_ERROR),
 590                                                                          errmsg("--%s requires a value",
 591                                                                                         optarg)));
 592                                                 else
 593                                                         ereport(ERROR,
 594                                                                         (errcode(ERRCODE_SYNTAX_ERROR),
 595                                                                          errmsg("-c %s requires a value",
 596                                                                                         optarg)));
 597                                         }
 598
 599                                         SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
 600                                         free(name);
 601                                         if (value)
 602                                                 free(value);
 603                                         break;
 604                                 }
 605
 606                         default:
 607                                 fprintf(stderr,
 608                                           gettext("Try \"%s --help\" for more information.\n"),
 609                                                 progname);
 610                                 ExitPostmaster(1);
 611                 }
 612         }
 613
 614         /*
 615          * Postmaster accepts no non-option switch arguments.
 616          */
 617         if (optind < argc)
 618         {
 619                 postmaster_error("invalid argument: \"%s\"", argv[optind]);
 620                 fprintf(stderr,
 621                                 gettext("Try \"%s --help\" for more information.\n"),
 622                                 progname);
 623                 ExitPostmaster(1);
 624         }
 625
 626         /*
 627          * Now we can set the data directory, and then read postgresql.conf.
 628          */
 629         checkDataDir(potential_DataDir);        /* issues error messages */
 630         SetDataDir(potential_DataDir);
 631
 632         ProcessConfigFile(PGC_POSTMASTER);
 633 #ifdef EXEC_BACKEND
 634         write_nondefault_variables(PGC_POSTMASTER);
 635 #endif
 636
 637         /*
 638          * Check for invalid combinations of GUC settings.
 639          */
 640         if (NBuffers < 2 * MaxBackends || NBuffers < 16)
 641         {
 642                 /*
 643                  * Do not accept -B so small that backends are likely to starve
 644                  * for lack of buffers.  The specific choices here are somewhat
 645                  * arbitrary.
 646                  */
 647                 postmaster_error("the number of buffers (-B) must be at least twice the number of allowed connections (-N) and at least 16");
 648                 ExitPostmaster(1);
 649         }
 650
 651         if (ReservedBackends >= MaxBackends)
 652         {
 653                 postmaster_error("superuser_reserved_connections must be less than max_connections");
 654                 ExitPostmaster(1);
 655         }
 656
 657         /*
 658          * Other one-time internal sanity checks can go here.
 659          */
 660         if (!CheckDateTokenTables())
 661         {
 662                 postmaster_error("invalid datetoken tables, please fix");
 663                 ExitPostmaster(1);
 664         }
 665
 666         /*
 667          * Now that we are done processing the postmaster arguments, reset
 668          * getopt(3) library so that it will work correctly in subprocesses.
 669          */
 670         optind = 1;
 671 #ifdef HAVE_INT_OPTRESET
 672         optreset = 1;                           /* some systems need this too */
 673 #endif
 674
 675         /* For debugging: display postmaster environment */
 676         {
 677                 extern char **environ;
 678                 char      **p;
 679
 680                 ereport(DEBUG3,
 681                                 (errmsg_internal("%s: PostmasterMain: initial environ dump:",
 682                                                                  progname)));
 683                 ereport(DEBUG3,
 684                                 (errmsg_internal("-----------------------------------------")));
 685                 for (p = environ; *p; ++p)
 686                         ereport(DEBUG3,
 687                                         (errmsg_internal("\t%s", *p)));
 688                 ereport(DEBUG3,
 689                                 (errmsg_internal("-----------------------------------------")));
 690         }
 691
 692         /*
 693          * On some systems our dynloader code needs the executable's pathname.
 694          */
 695         if (FindExec(pg_pathname, progname, "postgres") < 0)
 696                 ereport(FATAL,
 697                                 (errmsg("%s: could not locate postgres executable",
 698                                                 progname)));
 699
 700         /*
 701          * Initialize SSL library, if specified.
 702          */
 703 #ifdef USE_SSL
 704         if (EnableSSL)
 705                 secure_initialize();
 706 #endif
 707
 708         /*
 709          * process any libraries that should be preloaded and optionally
 710          * pre-initialized
 711          */
 712         if (preload_libraries_string)
 713                 process_preload_libraries(preload_libraries_string);
 714
 715         /*
 716          * Fork away from controlling terminal, if -S specified.
 717          *
 718          * Must do this before we grab any interlock files, else the interlocks
 719          * will show the wrong PID.
 720          */
 721         if (SilentMode)
 722                 pmdaemonize(argc, argv);
 723
 724         /*
 725          * Create lockfile for data directory.
 726          *
 727          * We want to do this before we try to grab the input sockets, because
 728          * the data directory interlock is more reliable than the socket-file
 729          * interlock (thanks to whoever decided to put socket files in /tmp
 730          * :-(). For the same reason, it's best to grab the TCP socket before
 731          * the Unix socket.
 732          */
 733         CreateDataDirLockFile(DataDir, true);
 734
 735         /*
 736          * Remove old temporary files.  At this point there can be no other
 737          * Postgres processes running in this directory, so this should be
 738          * safe.
 739          */
 740         RemovePgTempFiles();
 741
 742         /*
 743          * Establish input sockets.
 744          */
 745         for (i = 0; i < MAXLISTEN; i++)
 746                 ListenSocket[i] = -1;
 747
 748         if (ListenAddresses)
 749         {
 750                 char       *curhost,
 751                                    *endptr;
 752                 char            c;
 753
 754                 curhost = ListenAddresses;
 755                 for (;;)
 756                 {
 757                         /* ignore whitespace */
 758                         while (isspace((unsigned char) *curhost))
 759                                 curhost++;
 760                         if (*curhost == '\0')
 761                                 break;
 762                         endptr = curhost;
 763                         while (*endptr != '\0' && !isspace((unsigned char) *endptr))
 764                                 endptr++;
 765                         c = *endptr;
 766                         *endptr = '\0';
 767                         if (strcmp(curhost,"*") == 0)
 768                                 status = StreamServerPort(AF_UNSPEC, NULL,
 769                                                                                   (unsigned short) PostPortNumber,
 770                                                                                   UnixSocketDir,
 771                                                                                   ListenSocket, MAXLISTEN);
 772                         else
 773                                 status = StreamServerPort(AF_UNSPEC, curhost,
 774                                                                                   (unsigned short) PostPortNumber,
 775                                                                                   UnixSocketDir,
 776                                                                                   ListenSocket, MAXLISTEN);
 777                         if (status != STATUS_OK)
 778                                 ereport(WARNING,
 779                                                 (errmsg("could not create listen socket for \"%s\"",
 780                                                                 curhost)));
 781                         *endptr = c;
 782                         if (c != '\0')
 783                                 curhost = endptr+1;
 784                         else
 785                                 break;
 786                 }
 787         }
 788
 789 #ifdef USE_RENDEZVOUS
 790         /* Register for Rendezvous only if we opened TCP socket(s) */
 791         if (ListenSocket[0] != -1 && rendezvous_name != NULL)
 792         {
 793                 DNSServiceRegistrationCreate(rendezvous_name,
 794                                                                          "_postgresql._tcp.",
 795                                                                          "",
 796                                                                          htonl(PostPortNumber),
 797                                                                          "",
 798                                                                          (DNSServiceRegistrationReply) reg_reply,
 799                                                                          NULL);
 800         }
 801 #endif
 802
 803 #ifdef HAVE_UNIX_SOCKETS
 804         status = StreamServerPort(AF_UNIX, NULL,
 805                                                           (unsigned short) PostPortNumber,
 806                                                           UnixSocketDir,
 807                                                           ListenSocket, MAXLISTEN);
 808         if (status != STATUS_OK)
 809                 ereport(WARNING,
 810                                 (errmsg("could not create Unix-domain socket")));
 811 #endif
 812
 813         /*
 814          * check that we have some socket to listen on
 815          */
 816         if (ListenSocket[0] == -1)
 817                 ereport(FATAL,
 818                                 (errmsg("no socket created for listening")));
 819
 820         XLOGPathInit();
 821
 822         /*
 823          * Set up shared memory and semaphores.
 824          */
 825         reset_shared(PostPortNumber);
 826
 827         /*
 828          * Estimate number of openable files.  This must happen after setting up
 829          * semaphores, because on some platforms semaphores count as open files.
 830          */
 831         set_max_safe_fds();
 832
 833         /*
 834          * Initialize the list of active backends.
 835          */
 836         BackendList = DLNewList();
 837
 838 #ifdef WIN32
 839         /*
 840          * Initialize the child pid/HANDLE arrays
 841          */
 842         win32_childPIDArray = (pid_t*)malloc(NUM_BACKENDARRAY_ELEMS*sizeof(pid_t));
 843         win32_childHNDArray = (HANDLE*)malloc(NUM_BACKENDARRAY_ELEMS*sizeof(HANDLE));
 844         if (!win32_childPIDArray || !win32_childHNDArray)
 845                 ereport(FATAL,
 846                                 (errcode(ERRCODE_OUT_OF_MEMORY),
 847                                  errmsg("out of memory")));
 848 #endif
 849
 850         /*
 851          * Record postmaster options.  We delay this till now to avoid
 852          * recording bogus options (eg, NBuffers too high for available
 853          * memory).
 854          */
 855         if (!CreateOptsFile(argc, argv))
 856                 ExitPostmaster(1);
 857
 858         /*
 859          * Set up signal handlers for the postmaster process.
 860          *
 861          * CAUTION: when changing this list, check for side-effects on the signal
 862          * handling setup of child processes.  See tcop/postgres.c,
 863          * bootstrap/bootstrap.c, and postmaster/pgstat.c.
 864          */
 865         pqinitmask();
 866         PG_SETMASK(&BlockSig);
 867
 868         pqsignal(SIGHUP, SIGHUP_handler);       /* reread config file and have
 869                                                                                  * children do same */
 870         pqsignal(SIGINT, pmdie);        /* send SIGTERM and ShutdownDataBase */
 871         pqsignal(SIGQUIT, pmdie);       /* send SIGQUIT and die */
 872         pqsignal(SIGTERM, pmdie);       /* wait for children and ShutdownDataBase */
 873         pqsignal(SIGALRM, SIG_IGN); /* ignored */
 874         pqsignal(SIGPIPE, SIG_IGN); /* ignored */
 875         pqsignal(SIGUSR1, sigusr1_handler); /* message from child process */
 876         pqsignal(SIGUSR2, dummy_handler);       /* unused, reserve for children */
 877         pqsignal(SIGCHLD, reaper);      /* handle child termination */
 878         pqsignal(SIGTTIN, SIG_IGN); /* ignored */
 879         pqsignal(SIGTTOU, SIG_IGN); /* ignored */
 880         /* ignore SIGXFSZ, so that ulimit violations work like disk full */
 881 #ifdef SIGXFSZ
 882         pqsignal(SIGXFSZ, SIG_IGN); /* ignored */
 883 #endif
 884
 885         /*
 886          * Reset whereToSendOutput from Debug (its starting state) to None.
 887          * This prevents ereport from sending log messages to stderr unless
 888          * the syslog/stderr switch permits.  We don't do this until the
 889          * postmaster is fully launched, since startup failures may as well be
 890          * reported to stderr.
 891          */
 892         whereToSendOutput = None;
 893
 894         /*
 895          * On many platforms, the first call of localtime() incurs significant
 896          * overhead to load timezone info from the system configuration files.
 897          * By doing it once in the postmaster, we avoid having to do it in
 898          * every started child process.  The savings are not huge, but they
 899          * add up...
 900          */
 901         {
 902                 time_t          now = time(NULL);
 903
 904                 (void) localtime(&now);
 905         }
 906
 907         /*
 908          * Initialize and try to startup the statistics collector process
 909          */
 910         pgstat_init();
 911         pgstat_start();
 912
 913         /*
 914          * Load cached files for client authentication.
 915          */
 916         load_hba();
 917         load_ident();
 918         load_user();
 919         load_group();
 920
 921         /*
 922          * We're ready to rock and roll...
 923          */
 924         StartupPID = StartupDataBase();
 925
 926         status = ServerLoop();
 927
 928         /*
 929          * ServerLoop probably shouldn't ever return, but if it does, close
 930          * down.
 931          */
 932         ExitPostmaster(status != STATUS_OK);
 933
 934         return 0;                                       /* not reached */
 935 }
 936
 937 static void
 938 pmdaemonize(int argc, char *argv[])
 939 {
 940 #ifdef WIN32
 941         /* not supported */
 942         elog(FATAL,"SilentMode not supported under WIN32");
 943 #else
 944         int                     i;
 945         pid_t           pid;
 946
 947 #ifdef LINUX_PROFILE
 948         struct itimerval prof_itimer;
 949 #endif
 950
 951 #ifdef LINUX_PROFILE
 952         /* see comments in BackendRun */
 953         getitimer(ITIMER_PROF, &prof_itimer);
 954 #endif
 955
 956         pid = fork();
 957         if (pid == (pid_t) -1)
 958         {
 959                 postmaster_error("could not fork background process: %s",
 960                                                  strerror(errno));
 961                 ExitPostmaster(1);
 962         }
 963         else if (pid)
 964         {                                                       /* parent */
 965                 /* Parent should just exit, without doing any atexit cleanup */
 966                 _exit(0);
 967         }
 968
 969 #ifdef LINUX_PROFILE
 970         setitimer(ITIMER_PROF, &prof_itimer, NULL);
 971 #endif
 972
 973         MyProcPid = getpid();           /* reset MyProcPid to child */
 974
 975 /* GH: If there's no setsid(), we hopefully don't need silent mode.
 976  * Until there's a better solution.
 977  */
 978 #ifdef HAVE_SETSID
 979         if (setsid() < 0)
 980         {
 981                 postmaster_error("could not dissociate from controlling TTY: %s",
 982                                                  strerror(errno));
 983                 ExitPostmaster(1);
 984         }
 985 #endif
 986         i = open(NULL_DEV, O_RDWR | PG_BINARY);
 987         dup2(i, 0);
 988         dup2(i, 1);
 989         dup2(i, 2);
 990         close(i);
 991 #endif
 992 }
 993
 994
 995
 996 /*
 997  * Print out help message
 998  */
 999 static void
1000 usage(const char *progname)
1001 {
1002         printf(gettext("%s is the PostgreSQL server.\n\n"), progname);
1003         printf(gettext("Usage:\n  %s [OPTION]...\n\n"), progname);
1004         printf(gettext("Options:\n"));
1005 #ifdef USE_ASSERT_CHECKING
1006         printf(gettext("  -A 1|0          enable/disable run-time assert checking\n"));
1007 #endif
1008         printf(gettext("  -B NBUFFERS     number of shared buffers\n"));
1009         printf(gettext("  -c NAME=VALUE   set run-time parameter\n"));
1010         printf(gettext("  -d 1-5          debugging level\n"));
1011         printf(gettext("  -D DATADIR      database directory\n"));
1012         printf(gettext("  -F              turn fsync off\n"));
1013         printf(gettext("  -h HOSTNAME     host name or IP address to listen on\n"));
1014         printf(gettext("  -i              enable TCP/IP connections\n"));
1015         printf(gettext("  -k DIRECTORY    Unix-domain socket location\n"));
1016 #ifdef USE_SSL
1017         printf(gettext("  -l              enable SSL connections\n"));
1018 #endif
1019         printf(gettext("  -N MAX-CONNECT  maximum number of allowed connections\n"));
1020         printf(gettext("  -o OPTIONS      pass \"OPTIONS\" to each server process\n"));
1021         printf(gettext("  -p PORT         port number to listen on\n"));
1022         printf(gettext("  -S              silent mode (start in background without logging output)\n"));
1023         printf(gettext("  --help          show this help, then exit\n"));
1024         printf(gettext("  --version       output version information, then exit\n"));
1025
1026         printf(gettext("\nDeveloper options:\n"));
1027         printf(gettext("  -n              do not reinitialize shared memory after abnormal exit\n"));
1028         printf(gettext("  -s              send SIGSTOP to all backend servers if one dies\n"));
1029
1030         printf(gettext("\nPlease read the documentation for the complete list of run-time\n"
1031                                    "configuration settings and how to set them on the command line or in\n"
1032                                    "the configuration file.\n\n"
1033                                    "Report bugs to <pgsql-bugs@postgresql.org>.\n"));
1034 }
1035
1036 static int
1037 ServerLoop(void)
1038 {
1039         fd_set          readmask;
1040         int                     nSockets;
1041         struct timeval now,
1042                                 later;
1043         struct timezone tz;
1044         int                     i;
1045
1046         gettimeofday(&now, &tz);
1047
1048         nSockets = initMasks(&readmask);
1049
1050         for (;;)
1051         {
1052                 Port       *port;
1053                 fd_set          rmask;
1054                 struct timeval timeout;
1055
1056                 /*
1057                  * The timeout for the select() below is normally set on the basis
1058                  * of the time to the next checkpoint.  However, if for some
1059                  * reason we don't have a next-checkpoint time, time out after 60
1060                  * seconds. This keeps checkpoint scheduling from locking up when
1061                  * we get new connection requests infrequently (since we are
1062                  * likely to detect checkpoint completion just after enabling
1063                  * signals below, after we've already made the decision about how
1064                  * long to wait this time).
1065                  */
1066                 timeout.tv_sec = 60;
1067                 timeout.tv_usec = 0;
1068
1069                 if (CheckPointPID == 0 && checkpointed &&
1070                         StartupPID == 0 && Shutdown == NoShutdown &&
1071                         !FatalError && random_seed != 0)
1072                 {
1073                         time_t          now = time(NULL);
1074
1075                         if (CheckPointTimeout + checkpointed > now)
1076                         {
1077                                 /*
1078                                  * Not time for checkpoint yet, so set select timeout
1079                                  */
1080                                 timeout.tv_sec = CheckPointTimeout + checkpointed - now;
1081                         }
1082                         else
1083                         {
1084                                 /* Time to make the checkpoint... */
1085                                 CheckPointPID = CheckPointDataBase();
1086
1087                                 /*
1088                                  * if fork failed, schedule another try at 0.1 normal
1089                                  * delay
1090                                  */
1091                                 if (CheckPointPID == 0)
1092                                 {
1093                                         timeout.tv_sec = CheckPointTimeout / 10;
1094                                         checkpointed = now + timeout.tv_sec - CheckPointTimeout;
1095                                 }
1096                         }
1097                 }
1098
1099                 /*
1100                  * If no background writer process is running and we should
1101                  * do background writing, start one. It doesn't matter if
1102                  * this fails, we'll just try again later.
1103                  */
1104                 if (BgWriterPID == 0 && BgWriterPercent > 0 &&
1105                         StartupPID == 0 && Shutdown == NoShutdown &&
1106                         !FatalError && random_seed != 0)
1107                 {
1108                         BgWriterPID = StartBackgroundWriter();
1109                 }
1110
1111                 /*
1112                  * Wait for something to happen.
1113                  */
1114                 memcpy((char *) &rmask, (char *) &readmask, sizeof(fd_set));
1115
1116                 PG_SETMASK(&UnBlockSig);
1117
1118                 if (select(nSockets, &rmask, NULL, NULL, &timeout) < 0)
1119                 {
1120                         PG_SETMASK(&BlockSig);
1121                         if (errno == EINTR || errno == EWOULDBLOCK)
1122                                 continue;
1123                         ereport(LOG,
1124                                         (errcode_for_socket_access(),
1125                                          errmsg("select() failed in postmaster: %m")));
1126                         return STATUS_ERROR;
1127                 }
1128
1129                 /*
1130                  * Block all signals until we wait again.  (This makes it safe for
1131                  * our signal handlers to do nontrivial work.)
1132                  */
1133                 PG_SETMASK(&BlockSig);
1134
1135                 /*
1136                  * Select a random seed at the time of first receiving a request.
1137                  */
1138                 while (random_seed == 0)
1139                 {
1140                         gettimeofday(&later, &tz);
1141
1142                         /*
1143                          * We are not sure how much precision is in tv_usec, so we
1144                          * swap the nibbles of 'later' and XOR them with 'now'. On the
1145                          * off chance that the result is 0, we loop until it isn't.
1146                          */
1147                         random_seed = now.tv_usec ^
1148                                 ((later.tv_usec << 16) |
1149                                  ((later.tv_usec >> 16) & 0xffff));
1150                 }
1151
1152                 /*
1153                  * New connection pending on any of our sockets? If so, fork a
1154                  * child process to deal with it.
1155                  */
1156                 for (i = 0; i < MAXLISTEN; i++)
1157                 {
1158                         if (ListenSocket[i] == -1)
1159                                 break;
1160                         if (FD_ISSET(ListenSocket[i], &rmask))
1161                         {
1162                                 port = ConnCreate(ListenSocket[i]);
1163                                 if (port)
1164                                 {
1165                                         BackendStartup(port);
1166
1167                                         /*
1168                                          * We no longer need the open socket or port structure
1169                                          * in this process
1170                                          */
1171                                         StreamClose(port->sock);
1172                                         ConnFree(port);
1173                                 }
1174                         }
1175                 }
1176
1177                 /* If we have lost the stats collector, try to start a new one */
1178                 if (!pgstat_is_running)
1179                         pgstat_start();
1180         }
1181 }
1182
1183
1184 /*
1185  * Initialise the masks for select() for the ports
1186  * we are listening on.  Return the number of sockets to listen on.
1187  */
1188
1189 static int
1190 initMasks(fd_set *rmask)
1191 {
1192         int                     nsocks = -1;
1193         int                     i;
1194
1195         FD_ZERO(rmask);
1196
1197         for (i = 0; i < MAXLISTEN; i++)
1198         {
1199                 int                     fd = ListenSocket[i];
1200
1201                 if (fd == -1)
1202                         break;
1203                 FD_SET(fd, rmask);
1204                 if (fd > nsocks)
1205                         nsocks = fd;
1206         }
1207
1208         return nsocks + 1;
1209 }
1210
1211
1212 /*
1213  * Read the startup packet and do something according to it.
1214  *
1215  * Returns STATUS_OK or STATUS_ERROR, or might call ereport(FATAL) and
1216  * not return at all.
1217  *
1218  * (Note that ereport(FATAL) stuff is sent to the client, so only use it
1219  * if that's what you want.  Return STATUS_ERROR if you don't want to
1220  * send anything to the client, which would typically be appropriate
1221  * if we detect a communications failure.)
1222  */
1223 static int
1224 ProcessStartupPacket(Port *port, bool SSLdone)
1225 {
1226         int32           len;
1227         void       *buf;
1228         ProtocolVersion proto;
1229         MemoryContext oldcontext;
1230
1231         if (pq_getbytes((char *) &len, 4) == EOF)
1232         {
1233                 /*
1234                  * EOF after SSLdone probably means the client didn't like our
1235                  * response to NEGOTIATE_SSL_CODE.      That's not an error condition,
1236                  * so don't clutter the log with a complaint.
1237                  */
1238                 if (!SSLdone)
1239                         ereport(COMMERROR,
1240                                         (errcode(ERRCODE_PROTOCOL_VIOLATION),
1241                                          errmsg("incomplete startup packet")));
1242                 return STATUS_ERROR;
1243         }
1244
1245         len = ntohl(len);
1246         len -= 4;
1247
1248         if (len < (int32) sizeof(ProtocolVersion) ||
1249                 len > MAX_STARTUP_PACKET_LENGTH)
1250         {
1251                 ereport(COMMERROR,
1252                                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
1253                                  errmsg("invalid length of startup packet")));
1254                 return STATUS_ERROR;
1255         }
1256
1257         /*
1258          * Allocate at least the size of an old-style startup packet, plus one
1259          * extra byte, and make sure all are zeroes.  This ensures we will
1260          * have null termination of all strings, in both fixed- and
1261          * variable-length packet layouts.
1262          */
1263         if (len <= (int32) sizeof(StartupPacket))
1264                 buf = palloc0(sizeof(StartupPacket) + 1);
1265         else
1266                 buf = palloc0(len + 1);
1267
1268         if (pq_getbytes(buf, len) == EOF)
1269         {
1270                 ereport(COMMERROR,
1271                                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
1272                                  errmsg("incomplete startup packet")));
1273                 return STATUS_ERROR;
1274         }
1275
1276         /*
1277          * The first field is either a protocol version number or a special
1278          * request code.
1279          */
1280         port->proto = proto = ntohl(*((ProtocolVersion *) buf));
1281
1282         if (proto == CANCEL_REQUEST_CODE)
1283         {
1284                 processCancelRequest(port, buf);
1285                 return 127;                             /* XXX */
1286         }
1287
1288         if (proto == NEGOTIATE_SSL_CODE && !SSLdone)
1289         {
1290                 char            SSLok;
1291
1292 #ifdef USE_SSL
1293                 /* No SSL when disabled or on Unix sockets */
1294                 if (!EnableSSL || IS_AF_UNIX(port->laddr.addr.ss_family))
1295                         SSLok = 'N';
1296                 else
1297                         SSLok = 'S';            /* Support for SSL */
1298 #else
1299                 SSLok = 'N';                    /* No support for SSL */
1300 #endif
1301                 if (send(port->sock, &SSLok, 1, 0) != 1)
1302                 {
1303                         ereport(COMMERROR,
1304                                         (errcode_for_socket_access(),
1305                                  errmsg("failed to send SSL negotiation response: %m")));
1306                         return STATUS_ERROR;    /* close the connection */
1307                 }
1308
1309 #ifdef USE_SSL
1310                 if (SSLok == 'S' && secure_open_server(port) == -1)
1311                         return STATUS_ERROR;
1312 #endif
1313                 /* regular startup packet, cancel, etc packet should follow... */
1314                 /* but not another SSL negotiation request */
1315                 return ProcessStartupPacket(port, true);
1316         }
1317
1318         /* Could add additional special packet types here */
1319
1320         /*
1321          * Set FrontendProtocol now so that ereport() knows what format to
1322          * send if we fail during startup.
1323          */
1324         FrontendProtocol = proto;
1325
1326         /* Check we can handle the protocol the frontend is using. */
1327
1328         if (PG_PROTOCOL_MAJOR(proto) < PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST) ||
1329           PG_PROTOCOL_MAJOR(proto) > PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST) ||
1330         (PG_PROTOCOL_MAJOR(proto) == PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST) &&
1331          PG_PROTOCOL_MINOR(proto) > PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST)))
1332                 ereport(FATAL,
1333                                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1334                                  errmsg("unsupported frontend protocol %u.%u: server supports %u.0 to %u.%u",
1335                                           PG_PROTOCOL_MAJOR(proto), PG_PROTOCOL_MINOR(proto),
1336                                                 PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST),
1337                                                 PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST),
1338                                                 PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST))));
1339
1340         /*
1341          * Now fetch parameters out of startup packet and save them into the
1342          * Port structure.      All data structures attached to the Port struct
1343          * must be allocated in TopMemoryContext so that they won't disappear
1344          * when we pass them to PostgresMain (see BackendRun).  We need not
1345          * worry about leaking this storage on failure, since we aren't in the
1346          * postmaster process anymore.
1347          */
1348         oldcontext = MemoryContextSwitchTo(TopMemoryContext);
1349
1350         if (PG_PROTOCOL_MAJOR(proto) >= 3)
1351         {
1352                 int32           offset = sizeof(ProtocolVersion);
1353
1354                 /*
1355                  * Scan packet body for name/option pairs.      We can assume any
1356                  * string beginning within the packet body is null-terminated,
1357                  * thanks to zeroing extra byte above.
1358                  */
1359                 port->guc_options = NIL;
1360
1361                 while (offset < len)
1362                 {
1363                         char       *nameptr = ((char *) buf) + offset;
1364                         int32           valoffset;
1365                         char       *valptr;
1366
1367                         if (*nameptr == '\0')
1368                                 break;                  /* found packet terminator */
1369                         valoffset = offset + strlen(nameptr) + 1;
1370                         if (valoffset >= len)
1371                                 break;                  /* missing value, will complain below */
1372                         valptr = ((char *) buf) + valoffset;
1373
1374                         if (strcmp(nameptr, "database") == 0)
1375                                 port->database_name = pstrdup(valptr);
1376                         else if (strcmp(nameptr, "user") == 0)
1377                                 port->user_name = pstrdup(valptr);
1378                         else if (strcmp(nameptr, "options") == 0)
1379                                 port->cmdline_options = pstrdup(valptr);
1380                         else
1381                         {
1382                                 /* Assume it's a generic GUC option */
1383                                 port->guc_options = lappend(port->guc_options,
1384                                                                                         pstrdup(nameptr));
1385                                 port->guc_options = lappend(port->guc_options,
1386                                                                                         pstrdup(valptr));
1387                         }
1388                         offset = valoffset + strlen(valptr) + 1;
1389                 }
1390
1391                 /*
1392                  * If we didn't find a packet terminator exactly at the end of the
1393                  * given packet length, complain.
1394                  */
1395                 if (offset != len - 1)
1396                         ereport(FATAL,
1397                                         (errcode(ERRCODE_PROTOCOL_VIOLATION),
1398                                          errmsg("invalid startup packet layout: expected terminator as last byte")));
1399         }
1400         else
1401         {
1402                 /*
1403                  * Get the parameters from the old-style, fixed-width-fields
1404                  * startup packet as C strings.  The packet destination was
1405                  * cleared first so a short packet has zeros silently added.  We
1406                  * have to be prepared to truncate the pstrdup result for oversize
1407                  * fields, though.
1408                  */
1409                 StartupPacket *packet = (StartupPacket *) buf;
1410
1411                 port->database_name = pstrdup(packet->database);
1412                 if (strlen(port->database_name) > sizeof(packet->database))
1413                         port->database_name[sizeof(packet->database)] = '\0';
1414                 port->user_name = pstrdup(packet->user);
1415                 if (strlen(port->user_name) > sizeof(packet->user))
1416                         port->user_name[sizeof(packet->user)] = '\0';
1417                 port->cmdline_options = pstrdup(packet->options);
1418                 if (strlen(port->cmdline_options) > sizeof(packet->options))
1419                         port->cmdline_options[sizeof(packet->options)] = '\0';
1420                 port->guc_options = NIL;
1421         }
1422
1423         /* Check a user name was given. */
1424         if (port->user_name == NULL || port->user_name[0] == '\0')
1425                 ereport(FATAL,
1426                                 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
1427                  errmsg("no PostgreSQL user name specified in startup packet")));
1428
1429         /* The database defaults to the user name. */
1430         if (port->database_name == NULL || port->database_name[0] == '\0')
1431                 port->database_name = pstrdup(port->user_name);
1432
1433         if (Db_user_namespace)
1434         {
1435                 /*
1436                  * If user@, it is a global user, remove '@'. We only want to do
1437                  * this if there is an '@' at the end and no earlier in the user
1438                  * string or they may fake as a local user of another database
1439                  * attaching to this database.
1440                  */
1441                 if (strchr(port->user_name, '@') ==
1442                         port->user_name + strlen(port->user_name) - 1)
1443                         *strchr(port->user_name, '@') = '\0';
1444                 else
1445                 {
1446                         /* Append '@' and dbname */
1447                         char       *db_user;
1448
1449                         db_user = palloc(strlen(port->user_name) +
1450                                                          strlen(port->database_name) + 2);
1451                         sprintf(db_user, "%s@%s", port->user_name, port->database_name);
1452                         port->user_name = db_user;
1453                 }
1454         }
1455
1456         /*
1457          * Truncate given database and user names to length of a Postgres
1458          * name.  This avoids lookup failures when overlength names are given.
1459          */
1460         if (strlen(port->database_name) >= NAMEDATALEN)
1461                 port->database_name[NAMEDATALEN - 1] = '\0';
1462         if (strlen(port->user_name) >= NAMEDATALEN)
1463                 port->user_name[NAMEDATALEN - 1] = '\0';
1464
1465         /*
1466          * Done putting stuff in TopMemoryContext.
1467          */
1468         MemoryContextSwitchTo(oldcontext);
1469
1470         /*
1471          * If we're going to reject the connection due to database state, say
1472          * so now instead of wasting cycles on an authentication exchange.
1473          * (This also allows a pg_ping utility to be written.)
1474          */
1475         switch (port->canAcceptConnections)
1476         {
1477                 case CAC_STARTUP:
1478                         ereport(FATAL,
1479                                         (errcode(ERRCODE_CANNOT_CONNECT_NOW),
1480                                          errmsg("the database system is starting up")));
1481                         break;
1482                 case CAC_SHUTDOWN:
1483                         ereport(FATAL,
1484                                         (errcode(ERRCODE_CANNOT_CONNECT_NOW),
1485                                          errmsg("the database system is shutting down")));
1486                         break;
1487                 case CAC_RECOVERY:
1488                         ereport(FATAL,
1489                                         (errcode(ERRCODE_CANNOT_CONNECT_NOW),
1490                                          errmsg("the database system is in recovery mode")));
1491                         break;
1492                 case CAC_TOOMANY:
1493                         ereport(FATAL,
1494                                         (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
1495                                          errmsg("sorry, too many clients already")));
1496                         break;
1497                 case CAC_OK:
1498                 default:
1499                         break;
1500         }
1501
1502         return STATUS_OK;
1503 }
1504
1505
1506 /*
1507  * The client has sent a cancel request packet, not a normal
1508  * start-a-new-connection packet.  Perform the necessary processing.
1509  * Nothing is sent back to the client.
1510  */
1511 static void
1512 processCancelRequest(Port *port, void *pkt)
1513 {
1514         CancelRequestPacket *canc = (CancelRequestPacket *) pkt;
1515         int                     backendPID;
1516         long            cancelAuthCode;
1517         Backend    *bp;
1518 #ifndef EXEC_BACKEND
1519         Dlelem     *curr;
1520 #else
1521         int i;
1522 #endif
1523
1524         backendPID = (int) ntohl(canc->backendPID);
1525         cancelAuthCode = (long) ntohl(canc->cancelAuthCode);
1526
1527         if (backendPID == CheckPointPID)
1528         {
1529                 ereport(DEBUG2,
1530                                 (errmsg_internal("ignoring cancel request for checkpoint process %d",
1531                                                                  backendPID)));
1532                 return;
1533         }
1534         else if (backendPID == BgWriterPID)
1535         {
1536                 ereport(DEBUG2,
1537                                 (errmsg_internal("ignoring cancel request for bgwriter process %d",
1538                                                                  backendPID)));
1539                 return;
1540         }
1541
1542         /* See if we have a matching backend */
1543 #ifndef EXEC_BACKEND
1544         for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr))
1545         {
1546                 bp = (Backend *) DLE_VAL(curr);
1547 #else
1548         for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++)
1549         {
1550                 bp = (Backend*) &ShmemBackendArray[i];
1551 #endif
1552                 if (bp->pid == backendPID)
1553                 {
1554                         if (bp->cancel_key == cancelAuthCode)
1555                         {
1556                                 /* Found a match; signal that backend to cancel current op */
1557                                 ereport(DEBUG2,
1558                                                 (errmsg_internal("processing cancel request: sending SIGINT to process %d",
1559                                                                                  backendPID)));
1560                                 kill(bp->pid, SIGINT);
1561                         }
1562                         else
1563                                 /* Right PID, wrong key: no way, Jose */
1564                                 ereport(DEBUG2,
1565                                                 (errmsg_internal("bad key in cancel request for process %d",
1566                                                                                  backendPID)));
1567                         return;
1568                 }
1569         }
1570
1571         /* No matching backend */
1572         ereport(DEBUG2,
1573                         (errmsg_internal("bad pid in cancel request for process %d",
1574                                                          backendPID)));
1575 }
1576
1577 /*
1578  * canAcceptConnections --- check to see if database state allows connections.
1579  */
1580 static enum CAC_state
1581 canAcceptConnections(void)
1582 {
1583         /* Can't start backends when in startup/shutdown/recovery state. */
1584         if (Shutdown > NoShutdown)
1585                 return CAC_SHUTDOWN;
1586         if (StartupPID)
1587                 return CAC_STARTUP;
1588         if (FatalError)
1589                 return CAC_RECOVERY;
1590
1591         /*
1592          * Don't start too many children.
1593          *
1594          * We allow more connections than we can have backends here because some
1595          * might still be authenticating; they might fail auth, or some
1596          * existing backend might exit before the auth cycle is completed. The
1597          * exact MaxBackends limit is enforced when a new backend tries to
1598          * join the shared-inval backend array.
1599          */
1600         if (CountChildren() >= 2 * MaxBackends)
1601                 return CAC_TOOMANY;
1602
1603         return CAC_OK;
1604 }
1605
1606
1607 /*
1608  * ConnCreate -- create a local connection data structure
1609  */
1610 static Port *
1611 ConnCreate(int serverFd)
1612 {
1613         Port       *port;
1614
1615         if (!(port = (Port *) calloc(1, sizeof(Port))))
1616         {
1617                 ereport(LOG,
1618                                 (errcode(ERRCODE_OUT_OF_MEMORY),
1619                                  errmsg("out of memory")));
1620                 ExitPostmaster(1);
1621         }
1622
1623         if (StreamConnection(serverFd, port) != STATUS_OK)
1624         {
1625                 StreamClose(port->sock);
1626                 ConnFree(port);
1627                 port = NULL;
1628         }
1629         else
1630         {
1631                 /*
1632                  * Precompute password salt values to use for this connection.
1633                  * It's slightly annoying to do this long in advance of knowing
1634                  * whether we'll need 'em or not, but we must do the random()
1635                  * calls before we fork, not after.  Else the postmaster's random
1636                  * sequence won't get advanced, and all backends would end up
1637                  * using the same salt...
1638                  */
1639                 RandomSalt(port->cryptSalt, port->md5Salt);
1640         }
1641
1642         return port;
1643 }
1644
1645
1646 /*
1647  * ConnFree -- free a local connection data structure
1648  */
1649 static void
1650 ConnFree(Port *conn)
1651 {
1652 #ifdef USE_SSL
1653         secure_close(conn);
1654 #endif
1655         free(conn);
1656 }
1657
1658
1659 /*
1660  * ClosePostmasterPorts -- close all the postmaster's open sockets
1661  *
1662  * This is called during child process startup to release file descriptors
1663  * that are not needed by that child process.  The postmaster still has
1664  * them open, of course.
1665  */
1666 void
1667 ClosePostmasterPorts(bool pgstat_too)
1668 {
1669         int                     i;
1670
1671         /* Close the listen sockets */
1672         for (i = 0; i < MAXLISTEN; i++)
1673         {
1674                 if (ListenSocket[i] != -1)
1675                 {
1676                         StreamClose(ListenSocket[i]);
1677                         ListenSocket[i] = -1;
1678                 }
1679         }
1680
1681         /* Close pgstat control sockets, unless we're starting pgstat itself */
1682         if (pgstat_too)
1683                 pgstat_close_sockets();
1684 }
1685
1686
1687 /*
1688  * reset_shared -- reset shared memory and semaphores
1689  */
1690 static void
1691 reset_shared(unsigned short port)
1692 {
1693         /*
1694          * Create or re-create shared memory and semaphores.
1695          *
1696          * Note: in each "cycle of life" we will normally assign the same IPC
1697          * keys (if using SysV shmem and/or semas), since the port number is
1698          * used to determine IPC keys.  This helps ensure that we will clean
1699          * up dead IPC objects if the postmaster crashes and is restarted.
1700          */
1701         CreateSharedMemoryAndSemaphores(false, MaxBackends, port);
1702 }
1703
1704
1705 /*
1706  * SIGHUP -- reread config files, and tell children to do same
1707  */
1708 static void
1709 SIGHUP_handler(SIGNAL_ARGS)
1710 {
1711         int                     save_errno = errno;
1712
1713         PG_SETMASK(&BlockSig);
1714
1715         if (Shutdown <= SmartShutdown)
1716         {
1717                 ereport(LOG,
1718                          (errmsg("received SIGHUP, reloading configuration files")));
1719                 ProcessConfigFile(PGC_SIGHUP);
1720 #ifdef EXEC_BACKEND
1721                 write_nondefault_variables(PGC_SIGHUP);
1722 #endif
1723                 SignalChildren(SIGHUP);
1724                 load_hba();
1725                 load_ident();
1726
1727                 /*
1728                  * Tell the background writer to terminate so that we
1729                  * will start a new one with a possibly changed config
1730                  */
1731                 if (BgWriterPID != 0)
1732                         kill(BgWriterPID, SIGTERM);
1733         }
1734
1735         PG_SETMASK(&UnBlockSig);
1736
1737         errno = save_errno;
1738 }
1739
1740
1741
1742 /*
1743  * pmdie -- signal handler for processing various postmaster signals.
1744  */
1745 static void
1746 pmdie(SIGNAL_ARGS)
1747 {
1748         int                     save_errno = errno;
1749
1750         PG_SETMASK(&BlockSig);
1751
1752         ereport(DEBUG2,
1753                         (errmsg_internal("postmaster received signal %d",
1754                                                          postgres_signal_arg)));
1755
1756         switch (postgres_signal_arg)
1757         {
1758                 case SIGTERM:
1759
1760                         /*
1761                          * Smart Shutdown:
1762                          *
1763                          * Wait for children to end their work and ShutdownDataBase.
1764                          */
1765                         if (Shutdown >= SmartShutdown)
1766                                 break;
1767                         Shutdown = SmartShutdown;
1768                         ereport(LOG,
1769                                         (errmsg("received smart shutdown request")));
1770
1771                         /* Must tell bgwriter to quit, or it never will... */
1772                         if (BgWriterPID != 0)
1773                                 kill(BgWriterPID, SIGTERM);
1774
1775                         if (DLGetHead(BackendList)) /* let reaper() handle this */
1776                                 break;
1777
1778                         /*
1779                          * No children left. Shutdown data base system.
1780                          */
1781                         if (StartupPID > 0 || FatalError)       /* let reaper() handle
1782                                                                                                  * this */
1783                                 break;
1784                         if (ShutdownPID > 0)
1785                         {
1786                                 elog(PANIC, "shutdown process %d already running",
1787                                          (int) ShutdownPID);
1788                                 abort();
1789                         }
1790
1791                         ShutdownPID = ShutdownDataBase();
1792                         break;
1793
1794                 case SIGINT:
1795
1796                         /*
1797                          * Fast Shutdown:
1798                          *
1799                          * Abort all children with SIGTERM (rollback active transactions
1800                          * and exit) and ShutdownDataBase when they are gone.
1801                          */
1802                         if (Shutdown >= FastShutdown)
1803                                 break;
1804                         Shutdown = FastShutdown;
1805                         ereport(LOG,
1806                                         (errmsg("received fast shutdown request")));
1807
1808                         if (DLGetHead(BackendList))
1809                         {
1810                                 if (!FatalError)
1811                                 {
1812                                         ereport(LOG,
1813                                                         (errmsg("aborting any active transactions")));
1814                                         SignalChildren(SIGTERM);
1815                                         /* reaper() does the rest */
1816                                 }
1817                                 break;
1818                         }
1819
1820                         /*
1821                          * No children left. Shutdown data base system.
1822                          *
1823                          * Unlike the previous case, it is not an error for the shutdown
1824                          * process to be running already (we could get SIGTERM followed
1825                          * shortly later by SIGINT).
1826                          */
1827                         if (StartupPID > 0 || FatalError)       /* let reaper() handle
1828                                                                                                  * this */
1829                                 break;
1830                         if (ShutdownPID == 0)
1831                                 ShutdownPID = ShutdownDataBase();
1832                         break;
1833
1834                 case SIGQUIT:
1835
1836                         /*
1837                          * Immediate Shutdown:
1838                          *
1839                          * abort all children with SIGQUIT and exit without attempt to
1840                          * properly shutdown data base system.
1841                          */
1842                         ereport(LOG,
1843                                         (errmsg("received immediate shutdown request")));
1844                         if (ShutdownPID > 0)
1845                                 kill(ShutdownPID, SIGQUIT);
1846                         if (StartupPID > 0)
1847                                 kill(StartupPID, SIGQUIT);
1848                         if (DLGetHead(BackendList))
1849                                 SignalChildren(SIGQUIT);
1850                         ExitPostmaster(0);
1851                         break;
1852         }
1853
1854         PG_SETMASK(&UnBlockSig);
1855
1856         errno = save_errno;
1857 }
1858
1859 /*
1860  * Reaper -- signal handler to cleanup after a backend (child) dies.
1861  */
1862 static void
1863 reaper(SIGNAL_ARGS)
1864 {
1865         int                     save_errno = errno;
1866
1867 #ifdef HAVE_WAITPID
1868         int                     status;                 /* backend exit status */
1869 #else
1870 #ifndef WIN32
1871         union wait      status;                 /* backend exit status */
1872 #endif
1873 #endif
1874         int                     exitstatus;
1875         int                     pid;                    /* process id of dead backend */
1876
1877         PG_SETMASK(&BlockSig);
1878
1879         ereport(DEBUG4,
1880                         (errmsg_internal("reaping dead processes")));
1881 #ifdef HAVE_WAITPID
1882         while ((pid = waitpid(-1, &status, WNOHANG)) > 0)
1883         {
1884                 exitstatus = status;
1885 #else
1886 #ifndef WIN32
1887         while ((pid = wait3(&status, WNOHANG, NULL)) > 0)
1888         {
1889                 exitstatus = status.w_status;
1890 #else
1891         while ((pid = win32_waitpid(&exitstatus)) > 0)
1892         {
1893                 /*
1894                  * We need to do this here, and not in CleanupProc, since this
1895                  * is to be called on all children when we are done with them.
1896                  * Could move to LogChildExit, but that seems like asking for
1897                  * future trouble...
1898                  */
1899                 win32_RemoveChild(pid);
1900 #endif
1901 #endif
1902
1903                 /*
1904                  * Check if this child was the statistics collector. If so, try to
1905                  * start a new one.  (If fail, we'll try again in future cycles of
1906                  * the main loop.)
1907                  */
1908                 if (pgstat_ispgstat(pid))
1909                 {
1910                         LogChildExit(LOG, gettext("statistics collector process"),
1911                                                  pid, exitstatus);
1912                         pgstat_start();
1913                         continue;
1914                 }
1915
1916                 /*
1917                  * Check if this child was a shutdown or startup process.
1918                  */
1919                 if (ShutdownPID > 0 && pid == ShutdownPID)
1920                 {
1921                         if (exitstatus != 0)
1922                         {
1923                                 LogChildExit(LOG, gettext("shutdown process"),
1924                                                          pid, exitstatus);
1925                                 ExitPostmaster(1);
1926                         }
1927                         /* Normal postmaster exit is here */
1928                         ExitPostmaster(0);
1929                 }
1930
1931                 if (StartupPID > 0 && pid == StartupPID)
1932                 {
1933                         if (exitstatus != 0)
1934                         {
1935                                 LogChildExit(LOG, gettext("startup process"),
1936                                                          pid, exitstatus);
1937                                 ereport(LOG,
1938                                                 (errmsg("aborting startup due to startup process failure")));
1939                                 ExitPostmaster(1);
1940                         }
1941                         StartupPID = 0;
1942
1943                         /*
1944                          * Startup succeeded - remember its ID and RedoRecPtr.
1945                          *
1946                          * NB: this MUST happen before we fork a checkpoint or shutdown
1947                          * subprocess, else they will have wrong local ThisStartUpId.
1948                          */
1949                         SetThisStartUpID();
1950
1951                         FatalError = false; /* done with recovery */
1952
1953                         /*
1954                          * Arrange for first checkpoint to occur after standard delay.
1955                          */
1956                         CheckPointPID = 0;
1957                         checkpointed = time(NULL);
1958
1959                         /*
1960                          * Go to shutdown mode if a shutdown request was pending.
1961                          */
1962                         if (Shutdown > NoShutdown)
1963                         {
1964                                 if (ShutdownPID > 0)
1965                                 {
1966                                         elog(PANIC, "startup process %d died while shutdown process %d already running",
1967                                                  pid, (int) ShutdownPID);
1968                                         abort();
1969                                 }
1970                                 ShutdownPID = ShutdownDataBase();
1971                         }
1972
1973                         goto reaper_done;
1974                 }
1975
1976                 /*
1977                  * Else do standard child cleanup.
1978                  */
1979                 CleanupProc(pid, exitstatus);
1980
1981         }                                                       /* loop over pending child-death reports */
1982
1983         if (FatalError)
1984         {
1985                 /*
1986                  * Wait for all children exit, then reset shmem and
1987                  * StartupDataBase.
1988                  */
1989                 if (DLGetHead(BackendList) || StartupPID > 0 || ShutdownPID > 0)
1990                         goto reaper_done;
1991                 ereport(LOG,
1992                         (errmsg("all server processes terminated; reinitializing")));
1993
1994                 shmem_exit(0);
1995                 reset_shared(PostPortNumber);
1996
1997                 StartupPID = StartupDataBase();
1998
1999                 goto reaper_done;
2000         }
2001
2002         if (Shutdown > NoShutdown)
2003         {
2004                 if (DLGetHead(BackendList))
2005                         goto reaper_done;
2006                 if (StartupPID > 0 || ShutdownPID > 0)
2007                         goto reaper_done;
2008                 ShutdownPID = ShutdownDataBase();
2009         }
2010
2011 reaper_done:
2012         PG_SETMASK(&UnBlockSig);
2013
2014         errno = save_errno;
2015 }
2016
2017
2018 /*
2019  * CleanupProc -- cleanup after terminated backend.
2020  *
2021  * Remove all local state associated with backend.
2022  */
2023 static void
2024 CleanupProc(int pid,
2025                         int exitstatus)         /* child's exit status. */
2026 {
2027         Dlelem     *curr,
2028                            *next;
2029         Backend    *bp;
2030
2031         LogChildExit(DEBUG2, gettext("child process"), pid, exitstatus);
2032
2033         /*
2034          * If a backend dies in an ugly way (i.e. exit status not 0) then we
2035          * must signal all other backends to quickdie.  If exit status is zero
2036          * we assume everything is hunky dory and simply remove the backend
2037          * from the active backend list.
2038          */
2039         if (exitstatus == 0)
2040         {
2041                 curr = DLGetHead(BackendList);
2042                 while (curr)
2043                 {
2044                         bp = (Backend *) DLE_VAL(curr);
2045                         if (bp->pid == pid)
2046                         {
2047 #ifdef EXEC_BACKEND
2048                                 ShmemBackendArrayRemove(bp->pid);
2049 #endif
2050                                 DLRemove(curr);
2051                                 free(bp);
2052                                 DLFreeElem(curr);
2053                                 break;
2054                         }
2055                         curr = DLGetSucc(curr);
2056                 }
2057
2058                 if (pid == CheckPointPID)
2059                 {
2060                         CheckPointPID = 0;
2061                         if (!FatalError)
2062                         {
2063                                 checkpointed = time(NULL);
2064                                 /* Update RedoRecPtr for future child backends */
2065                                 GetSavedRedoRecPtr();
2066                         }
2067                 }
2068                 else if (pid == BgWriterPID)
2069                         BgWriterPID = 0;
2070                 else
2071                         pgstat_beterm(pid);
2072
2073                 return;
2074         }
2075
2076         /* below here we're dealing with a non-normal exit */
2077
2078         /* Make log entry unless we did so already */
2079         if (!FatalError)
2080         {
2081                 LogChildExit(LOG,
2082                                          (pid == CheckPointPID) ? gettext("checkpoint process") :
2083                                          (pid == BgWriterPID) ? gettext("bgwriter process") :
2084                                          gettext("server process"),
2085                                          pid, exitstatus);
2086                 ereport(LOG,
2087                           (errmsg("terminating any other active server processes")));
2088         }
2089
2090         curr = DLGetHead(BackendList);
2091         while (curr)
2092         {
2093                 next = DLGetSucc(curr);
2094                 bp = (Backend *) DLE_VAL(curr);
2095                 if (bp->pid != pid)
2096                 {
2097                         /*
2098                          * This backend is still alive.  Unless we did so already,
2099                          * tell it to commit hara-kiri.
2100                          *
2101                          * SIGQUIT is the special signal that says exit without proc_exit
2102                          * and let the user know what's going on. But if SendStop is
2103                          * set (-s on command line), then we send SIGSTOP instead, so
2104                          * that we can get core dumps from all backends by hand.
2105                          */
2106                         if (!FatalError)
2107                         {
2108                                 ereport(DEBUG2,
2109                                                 (errmsg_internal("sending %s to process %d",
2110                                                                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
2111                                                                                  (int) bp->pid)));
2112                                 kill(bp->pid, (SendStop ? SIGSTOP : SIGQUIT));
2113                         }
2114                 }
2115                 else
2116                 {
2117                         /*
2118                          * Found entry for freshly-dead backend, so remove it.
2119                          */
2120 #ifdef EXEC_BACKEND
2121                         ShmemBackendArrayRemove(bp->pid);
2122 #endif
2123                         DLRemove(curr);
2124                         free(bp);
2125                         DLFreeElem(curr);
2126                 }
2127                 curr = next;
2128         }
2129
2130         if (pid == CheckPointPID)
2131         {
2132                 CheckPointPID = 0;
2133                 checkpointed = 0;
2134         }
2135         else if (pid == BgWriterPID)
2136         {
2137                 BgWriterPID = 0;
2138         }
2139         else
2140         {
2141                 /*
2142                  * Tell the collector about backend termination
2143                  */
2144                 pgstat_beterm(pid);
2145         }
2146
2147         FatalError = true;
2148 }
2149
2150 /*
2151  * Log the death of a child process.
2152  */
2153 static void
2154 LogChildExit(int lev, const char *procname, int pid, int exitstatus)
2155 {
2156         if (WIFEXITED(exitstatus))
2157                 ereport(lev,
2158
2159                 /*
2160                  * translator: %s is a noun phrase describing a child process,
2161                  * such as "server process"
2162                  */
2163                                 (errmsg("%s (PID %d) exited with exit code %d",
2164                                                 procname, pid, WEXITSTATUS(exitstatus))));
2165         else if (WIFSIGNALED(exitstatus))
2166                 ereport(lev,
2167
2168                 /*
2169                  * translator: %s is a noun phrase describing a child process,
2170                  * such as "server process"
2171                  */
2172                                 (errmsg("%s (PID %d) was terminated by signal %d",
2173                                                 procname, pid, WTERMSIG(exitstatus))));
2174         else
2175                 ereport(lev,
2176
2177                 /*
2178                  * translator: %s is a noun phrase describing a child process,
2179                  * such as "server process"
2180                  */
2181                                 (errmsg("%s (PID %d) exited with unexpected status %d",
2182                                                 procname, pid, exitstatus)));
2183 }
2184
2185 /*
2186  * Send a signal to all backend children.
2187  */
2188 static void
2189 SignalChildren(int signal)
2190 {
2191         Dlelem     *curr,
2192                            *next;
2193         Backend    *bp;
2194
2195         curr = DLGetHead(BackendList);
2196         while (curr)
2197         {
2198                 next = DLGetSucc(curr);
2199                 bp = (Backend *) DLE_VAL(curr);
2200
2201                 if (bp->pid != MyProcPid)
2202                 {
2203                         ereport(DEBUG2,
2204                                         (errmsg_internal("sending signal %d to process %d",
2205                                                                          signal,
2206                                                                          (int) bp->pid)));
2207                         kill(bp->pid, signal);
2208                 }
2209
2210                 curr = next;
2211         }
2212 }
2213
2214 /*
2215  * BackendStartup -- start backend process
2216  *
2217  * returns: STATUS_ERROR if the fork failed, STATUS_OK otherwise.
2218  */
2219 static int
2220 BackendStartup(Port *port)
2221 {
2222         Backend    *bn;                         /* for backend cleanup */
2223         pid_t           pid;
2224
2225 #ifdef LINUX_PROFILE
2226         struct itimerval prof_itimer;
2227 #endif
2228
2229         /*
2230          * Compute the cancel key that will be assigned to this backend. The
2231          * backend will have its own copy in the forked-off process' value of
2232          * MyCancelKey, so that it can transmit the key to the frontend.
2233          */
2234         MyCancelKey = PostmasterRandom();
2235
2236         /*
2237          * Make room for backend data structure.  Better before the fork() so
2238          * we can handle failure cleanly.
2239          */
2240         bn = (Backend *) malloc(sizeof(Backend));
2241         if (!bn)
2242         {
2243                 ereport(LOG,
2244                                 (errcode(ERRCODE_OUT_OF_MEMORY),
2245                                  errmsg("out of memory")));
2246                 return STATUS_ERROR;
2247         }
2248
2249         /*
2250          * Flush stdio channels just before fork, to avoid double-output
2251          * problems. Ideally we'd use fflush(NULL) here, but there are still a
2252          * few non-ANSI stdio libraries out there (like SunOS 4.1.x) that
2253          * coredump if we do. Presently stdout and stderr are the only stdio
2254          * output channels used by the postmaster, so fflush'ing them should
2255          * be sufficient.
2256          */
2257         fflush(stdout);
2258         fflush(stderr);
2259
2260 #ifdef LINUX_PROFILE
2261
2262         /*
2263          * Linux's fork() resets the profiling timer in the child process. If
2264          * we want to profile child processes then we need to save and restore
2265          * the timer setting.  This is a waste of time if not profiling,
2266          * however, so only do it if commanded by specific -DLINUX_PROFILE
2267          * switch.
2268          */
2269         getitimer(ITIMER_PROF, &prof_itimer);
2270 #endif
2271
2272 #ifdef __BEOS__
2273         /* Specific beos actions before backend startup */
2274         beos_before_backend_startup();
2275 #endif
2276
2277         port->canAcceptConnections = canAcceptConnections();
2278 #ifdef EXEC_BACKEND
2279         pid = Backend_forkexec(port);
2280 #else
2281         pid = fork();
2282
2283         if (pid == 0)                           /* child */
2284         {
2285 #ifdef LINUX_PROFILE
2286                 setitimer(ITIMER_PROF, &prof_itimer, NULL);
2287 #endif
2288
2289 #ifdef __BEOS__
2290                 /* Specific beos backend startup actions */
2291                 beos_backend_startup();
2292 #endif
2293                 free(bn);
2294
2295                 proc_exit(BackendRun(port));
2296         }
2297 #endif
2298
2299         /* in parent, error */
2300         if (pid < 0)
2301         {
2302                 int                     save_errno = errno;
2303
2304 #ifdef __BEOS__
2305                 /* Specific beos backend startup actions */
2306                 beos_backend_startup_failed();
2307 #endif
2308                 free(bn);
2309                 errno = save_errno;
2310                 ereport(LOG,
2311                           (errmsg("could not fork new process for connection: %m")));
2312                 report_fork_failure_to_client(port, save_errno);
2313                 return STATUS_ERROR;
2314         }
2315
2316         /* in parent, normal */
2317         ereport(DEBUG2,
2318                         (errmsg_internal("forked new backend, pid=%d socket=%d",
2319                                                          (int) pid, port->sock)));
2320
2321         /*
2322          * Everything's been successful, it's safe to add this backend to our
2323          * list of backends.
2324          */
2325         bn->pid = pid;
2326         bn->cancel_key = MyCancelKey;
2327 #ifdef EXEC_BACKEND
2328         ShmemBackendArrayAdd(bn);
2329 #endif
2330         DLAddHead(BackendList, DLNewElem(bn));
2331
2332         return STATUS_OK;
2333 }
2334
2335 /*
2336  * Try to report backend fork() failure to client before we close the
2337  * connection.  Since we do not care to risk blocking the postmaster on
2338  * this connection, we set the connection to non-blocking and try only once.
2339  *
2340  * This is grungy special-purpose code; we cannot use backend libpq since
2341  * it's not up and running.
2342  */
2343 static void
2344 report_fork_failure_to_client(Port *port, int errnum)
2345 {
2346         char            buffer[1000];
2347
2348         /* Format the error message packet (always V2 protocol) */
2349         snprintf(buffer, sizeof(buffer), "E%s%s\n",
2350                          gettext("could not fork new process for connection: "),
2351                          strerror(errnum));
2352
2353         /* Set port to non-blocking.  Don't do send() if this fails */
2354         if (!set_noblock(port->sock))
2355                 return;
2356
2357         send(port->sock, buffer, strlen(buffer) + 1, 0);
2358 }
2359
2360
2361 /*
2362  * split_opts -- split a string of options and append it to an argv array
2363  *
2364  * NB: the string is destructively modified!
2365  *
2366  * Since no current POSTGRES arguments require any quoting characters,
2367  * we can use the simple-minded tactic of assuming each set of space-
2368  * delimited characters is a separate argv element.
2369  *
2370  * If you don't like that, well, we *used* to pass the whole option string
2371  * as ONE argument to execl(), which was even less intelligent...
2372  */
2373 static void
2374 split_opts(char **argv, int *argcp, char *s)
2375 {
2376         while (s && *s)
2377         {
2378                 while (isspace((unsigned char) *s))
2379                         ++s;
2380                 if (*s == '\0')
2381                         break;
2382                 argv[(*argcp)++] = s;
2383                 while (*s && !isspace((unsigned char) *s))
2384                         ++s;
2385                 if (*s)
2386                         *s++ = '\0';
2387         }
2388 }
2389
2390
2391 /*
2392  * BackendInit/Run -- perform authentication [BackendInit], and if successful,
2393  *              set up the backend's argument list [BackendRun] and invoke
2394  *              backend main()
2395  *
2396  * returns:
2397  *              Shouldn't return at all.
2398  *              If PostgresMain() fails, return status.
2399  */
2400 static void
2401 BackendInit(Port *port)
2402 {
2403         int                     status;
2404         struct timeval now;
2405         struct timezone tz;
2406         char            remote_host[NI_MAXHOST];
2407         char            remote_port[NI_MAXSERV];
2408         char            remote_ps_data[NI_MAXHOST];
2409
2410         IsUnderPostmaster = true;       /* we are a postmaster subprocess now */
2411
2412         ClientAuthInProgress = true;    /* limit visibility of log messages */
2413
2414         /* We don't want the postmaster's proc_exit() handlers */
2415         on_exit_reset();
2416
2417         /*
2418          * Signal handlers setting is moved to tcop/postgres...
2419          */
2420
2421         /* save start time for end of session reporting */
2422         gettimeofday(&(port->session_start),NULL);
2423
2424         /* set these to empty in case they are needed before we set them up */
2425         port->remote_host = "";
2426         port->remote_port = "";
2427         port->commandTag = "";
2428
2429         /* Save port etc. for ps status */
2430         MyProcPort = port;
2431
2432         /* Reset MyProcPid to new backend's pid */
2433         MyProcPid = getpid();
2434
2435         /*
2436          * Initialize libpq and enable reporting of ereport errors to the
2437          * client. Must do this now because authentication uses libpq to send
2438          * messages.
2439          */
2440         pq_init();                                      /* initialize libpq to talk to client */
2441         whereToSendOutput = Remote; /* now safe to ereport to client */
2442
2443         /*
2444          * We arrange for a simple exit(0) if we receive SIGTERM or SIGQUIT
2445          * during any client authentication related communication. Otherwise
2446          * the postmaster cannot shutdown the database FAST or IMMED cleanly
2447          * if a buggy client blocks a backend during authentication.
2448          */
2449         pqsignal(SIGTERM, authdie);
2450         pqsignal(SIGQUIT, authdie);
2451         pqsignal(SIGALRM, authdie);
2452         PG_SETMASK(&AuthBlockSig);
2453
2454         /*
2455          * Get the remote host name and port for logging and status display.
2456          */
2457         remote_host[0] = '\0';
2458         remote_port[0] = '\0';
2459         if (getnameinfo_all(&port->raddr.addr, port->raddr.salen,
2460                                                 remote_host, sizeof(remote_host),
2461                                                 remote_port, sizeof(remote_port),
2462                                    (log_hostname ? 0 : NI_NUMERICHOST) | NI_NUMERICSERV))
2463         {
2464                 getnameinfo_all(&port->raddr.addr, port->raddr.salen,
2465                                                 remote_host, sizeof(remote_host),
2466                                                 remote_port, sizeof(remote_port),
2467                                                 NI_NUMERICHOST | NI_NUMERICSERV);
2468         }
2469         snprintf(remote_ps_data, sizeof(remote_ps_data),
2470                          remote_port[0] == '\0' ? "%s" : "%s(%s)",
2471                          remote_host, remote_port);
2472
2473         if (Log_connections)
2474                 ereport(LOG,
2475                                 (errmsg("connection received: host=%s port=%s",
2476                                                 remote_host, remote_port)));
2477
2478         /*
2479          * save remote_host and remote_port in port stucture
2480          */
2481         port->remote_host = strdup(remote_host);
2482         port->remote_port = strdup(remote_port);
2483
2484         /*
2485          * Ready to begin client interaction.  We will give up and exit(0)
2486          * after a time delay, so that a broken client can't hog a connection
2487          * indefinitely.  PreAuthDelay doesn't count against the time limit.
2488          */
2489         if (!enable_sig_alarm(AuthenticationTimeout * 1000, false))
2490                 elog(FATAL, "could not set timer for authorization timeout");
2491
2492         /*
2493          * Receive the startup packet (which might turn out to be a cancel
2494          * request packet).
2495          */
2496         status = ProcessStartupPacket(port, false);
2497
2498         if (status != STATUS_OK)
2499                 proc_exit(0);
2500
2501         /*
2502          * Now that we have the user and database name, we can set the process
2503          * title for ps.  It's good to do this as early as possible in
2504          * startup.
2505          */
2506         init_ps_display(port->user_name, port->database_name, remote_ps_data);
2507         set_ps_display("authentication");
2508
2509         /*
2510          * Now perform authentication exchange.
2511          */
2512         ClientAuthentication(port); /* might not return, if failure */
2513
2514         /*
2515          * Done with authentication.  Disable timeout, and prevent
2516          * SIGTERM/SIGQUIT again until backend startup is complete.
2517          */
2518         if (!disable_sig_alarm(false))
2519                 elog(FATAL, "could not disable timer for authorization timeout");
2520         PG_SETMASK(&BlockSig);
2521
2522         if (Log_connections)
2523                 ereport(LOG,
2524                                 (errmsg("connection authorized: user=%s database=%s",
2525                                                 port->user_name, port->database_name)));
2526
2527         /*
2528          * Don't want backend to be able to see the postmaster random number
2529          * generator state.  We have to clobber the static random_seed *and*
2530          * start a new random sequence in the random() library function.
2531          */
2532         random_seed = 0;
2533         gettimeofday(&now, &tz);
2534         srandom((unsigned int) now.tv_usec);
2535 }
2536
2537
2538 static int
2539 BackendRun(Port *port)
2540 {
2541         char      **av;
2542         int                     maxac;
2543         int                     ac;
2544         char            debugbuf[32];
2545         char            protobuf[32];
2546         int                     i;
2547
2548         /*
2549          * Let's clean up ourselves as the postmaster child, and
2550          * close the postmaster's other sockets
2551          */
2552         ClosePostmasterPorts(true);
2553
2554         /*
2555          * PreAuthDelay is a debugging aid for investigating problems in the
2556          * authentication cycle: it can be set in postgresql.conf to allow
2557          * time to attach to the newly-forked backend with a debugger. (See
2558          * also the -W backend switch, which we allow clients to pass through
2559          * PGOPTIONS, but it is not honored until after authentication.)
2560          */
2561         if (PreAuthDelay > 0)
2562                 pg_usleep(PreAuthDelay*1000000L);
2563
2564         /* Will exit on failure */
2565         BackendInit(port);
2566
2567
2568         /* ----------------
2569          * Now, build the argv vector that will be given to PostgresMain.
2570          *
2571          * The layout of the command line is
2572          *              postgres [secure switches] -p databasename [insecure switches]
2573          * where the switches after -p come from the client request.
2574          *
2575          * The maximum possible number of commandline arguments that could come
2576          * from ExtraOptions or port->cmdline_options is (strlen + 1) / 2; see
2577          * split_opts().
2578          * ----------------
2579          */
2580         maxac = 10;                                     /* for fixed args supplied below */
2581         maxac += (strlen(ExtraOptions) + 1) / 2;
2582         if (port->cmdline_options)
2583                 maxac += (strlen(port->cmdline_options) + 1) / 2;
2584
2585         av = (char **) MemoryContextAlloc(TopMemoryContext,
2586                                                                           maxac * sizeof(char *));
2587         ac = 0;
2588
2589         av[ac++] = "postgres";
2590
2591         /*
2592          * Pass the requested debugging level along to the backend.
2593          */
2594         if (debug_flag > 0)
2595         {
2596                 snprintf(debugbuf, sizeof(debugbuf), "-d%d", debug_flag);
2597                 av[ac++] = debugbuf;
2598         }
2599
2600         /*
2601          * Pass any backend switches specified with -o in the postmaster's own
2602          * command line.  We assume these are secure.
2603          */
2604         split_opts(av, &ac, ExtraOptions);
2605
2606         /* Tell the backend what protocol the frontend is using. */
2607         snprintf(protobuf, sizeof(protobuf), "-v%u", port->proto);
2608         av[ac++] = protobuf;
2609
2610 #ifdef EXEC_BACKEND
2611         /* pass data dir before end of secure switches (-p) */
2612         av[ac++] = "-D";
2613         av[ac++] = DataDir;
2614 #endif
2615
2616         /*
2617          * Tell the backend it is being called from the postmaster, and which
2618          * database to use.  -p marks the end of secure switches.
2619          */
2620         av[ac++] = "-p";
2621         av[ac++] = port->database_name;
2622
2623         /*
2624          * Pass the (insecure) option switches from the connection request.
2625          * (It's OK to mangle port->cmdline_options now.)
2626          */
2627         if (port->cmdline_options)
2628                 split_opts(av, &ac, port->cmdline_options);
2629
2630         av[ac] = NULL;
2631
2632         Assert(ac < maxac);
2633
2634         /*
2635          * Release postmaster's working memory context so that backend can
2636          * recycle the space.  Note this does not trash *MyProcPort, because
2637          * ConnCreate() allocated that space with malloc() ... else we'd need
2638          * to copy the Port data here.  Also, subsidiary data such as the
2639          * username isn't lost either; see ProcessStartupPacket().
2640          */
2641         MemoryContextSwitchTo(TopMemoryContext);
2642 #ifndef EXEC_BACKEND
2643         MemoryContextDelete(PostmasterContext);
2644 #endif
2645         PostmasterContext = NULL;
2646
2647         /*
2648          * Debug: print arguments being passed to backend
2649          */
2650         ereport(DEBUG3,
2651                         (errmsg_internal("%s child[%d]: starting with (",
2652                                                          progname, getpid())));
2653         for (i = 0; i < ac; ++i)
2654                 ereport(DEBUG3,
2655                                 (errmsg_internal("\t%s", av[i])));
2656         ereport(DEBUG3,
2657                         (errmsg_internal(")")));
2658
2659         ClientAuthInProgress = false;           /* client_min_messages is active
2660                                                                                  * now */
2661
2662         return (PostgresMain(ac, av, port->user_name));
2663 }
2664
2665
2666 #ifdef EXEC_BACKEND
2667
2668
2669 /*
2670  * SubPostmasterMain -- prepare the fork/exec'd process to be in an equivalent
2671  *                      state (for calling BackendRun) as a forked process.
2672  *
2673  * returns:
2674  *              Shouldn't return at all.
2675  */
2676 void
2677 SubPostmasterMain(int argc, char* argv[])
2678 {
2679         unsigned long   backendID;
2680         Port                    port;
2681
2682         memset((void*)&port, 0, sizeof(Port));
2683         Assert(argc == 2);
2684
2685         /* Do this sooner rather than later... */
2686         IsUnderPostmaster = true;       /* we are a postmaster subprocess now */
2687
2688         /* In EXEC case we will not have inherited these settings */
2689         IsPostmasterEnvironment = true;
2690         whereToSendOutput = None;
2691
2692         /* Setup global context */
2693         MemoryContextInit();
2694         InitializeGUCOptions();
2695
2696         /* Parse passed-in context */
2697         argc = 0;
2698         backendID               = (unsigned long)atol(argv[argc++]);
2699         DataDir                 = strdup(argv[argc++]);
2700
2701         /* Read in file-based context */
2702         read_nondefault_variables();
2703         read_backend_variables(backendID,&port);
2704
2705         /* Remaining initialization */
2706         pgstat_init_forkexec_backend();
2707
2708         /* FIXME: [fork/exec] Ugh */
2709         load_hba();
2710         load_ident();
2711         load_user();
2712         load_group();
2713
2714         /* Attach process to shared segments */
2715         CreateSharedMemoryAndSemaphores(false, MaxBackends, 0);
2716
2717         /* Run backend */
2718         proc_exit(BackendRun(&port));
2719 }
2720
2721
2722 /*
2723  * Backend_forkexec -- fork/exec off a backend process
2724  *
2725  * returns:
2726  *              the pid of the fork/exec'd process
2727  */
2728 static pid_t
2729 Backend_forkexec(Port *port)
2730 {
2731         pid_t pid;
2732         char *av[5];
2733         int ac = 0, bufc = 0, i;
2734         char buf[2][MAXPGPATH];
2735
2736         if (!write_backend_variables(port))
2737                 return -1; /* log made by write_backend_variables */
2738
2739         av[ac++] = "postgres";
2740         av[ac++] = "-forkexec";
2741
2742         /* Format up context to pass to exec'd process */
2743         snprintf(buf[bufc++],MAXPGPATH,"%lu",tmpBackendFileNum);
2744         snprintf(buf[bufc++],MAXPGPATH,"\"%s\"",DataDir);
2745
2746         /* Add to the arg list */
2747         Assert(bufc <= lengthof(buf));
2748         for (i = 0; i < bufc; i++)
2749                 av[ac++] = buf[i];
2750
2751         /* FIXME: [fork/exec] ExtraOptions? */
2752
2753         av[ac++] = NULL;
2754         Assert(ac <= lengthof(av));
2755
2756 #ifdef WIN32
2757         pid = win32_forkexec(pg_pathname,av); /* logs on error */
2758 #else
2759         /* Fire off execv in child */
2760         if ((pid = fork()) == 0 && (execv(pg_pathname,av) == -1))
2761                 /*
2762                  * FIXME: [fork/exec] suggestions for what to do here?
2763                  *  Probably OK to issue error (unlike pgstat case)
2764                  */
2765                 abort();
2766 #endif
2767         return pid; /* Parent returns pid */
2768 }
2769
2770 #endif
2771
2772
2773 /*
2774  * ExitPostmaster -- cleanup
2775  *
2776  * Do NOT call exit() directly --- always go through here!
2777  */
2778 static void
2779 ExitPostmaster(int status)
2780 {
2781         /* should cleanup shared memory and kill all backends */
2782
2783         /*
2784          * Not sure of the semantics here.      When the Postmaster dies, should
2785          * the backends all be killed? probably not.
2786          *
2787          * MUST         -- vadim 05-10-1999
2788          */
2789         /* Should I use true instead? */
2790         ClosePostmasterPorts(false);
2791
2792         proc_exit(status);
2793 }
2794
2795 /*
2796  * sigusr1_handler - handle signal conditions from child processes
2797  */
2798 static void
2799 sigusr1_handler(SIGNAL_ARGS)
2800 {
2801         int                     save_errno = errno;
2802
2803         PG_SETMASK(&BlockSig);
2804
2805         if (CheckPostmasterSignal(PMSIGNAL_DO_CHECKPOINT))
2806         {
2807                 if (CheckPointWarning != 0)
2808                 {
2809                         /*
2810                          * This only times checkpoints forced by running out of
2811                          * segment files.  Other checkpoints could reduce the
2812                          * frequency of forced checkpoints.
2813                          */
2814                         time_t          now = time(NULL);
2815
2816                         if (LastSignalledCheckpoint != 0)
2817                         {
2818                                 int                     elapsed_secs = now - LastSignalledCheckpoint;
2819
2820                                 if (elapsed_secs < CheckPointWarning)
2821                                         ereport(LOG,
2822                                                         (errmsg("checkpoints are occurring too frequently (%d seconds apart)",
2823                                                                         elapsed_secs),
2824                                         errhint("Consider increasing the configuration parameter \"checkpoint_segments\".")));
2825                         }
2826                         LastSignalledCheckpoint = now;
2827                 }
2828
2829                 /*
2830                  * Request to schedule a checkpoint
2831                  *
2832                  * Ignore request if checkpoint is already running or checkpointing
2833                  * is currently disabled
2834                  */
2835                 if (CheckPointPID == 0 && checkpointed &&
2836                         StartupPID == 0 && Shutdown == NoShutdown &&
2837                         !FatalError && random_seed != 0)
2838                 {
2839                         CheckPointPID = CheckPointDataBase();
2840                         /* note: if fork fails, CheckPointPID stays 0; nothing happens */
2841                 }
2842         }
2843
2844         if (CheckPostmasterSignal(PMSIGNAL_PASSWORD_CHANGE))
2845         {
2846                 /*
2847                  * Password or group file has changed.
2848                  */
2849                 load_user();
2850                 load_group();
2851         }
2852
2853         if (CheckPostmasterSignal(PMSIGNAL_WAKEN_CHILDREN))
2854         {
2855                 /*
2856                  * Send SIGUSR2 to all children (triggers AsyncNotifyHandler). See
2857                  * storage/ipc/sinvaladt.c for the use of this.
2858                  */
2859                 if (Shutdown == NoShutdown)
2860                         SignalChildren(SIGUSR2);
2861         }
2862
2863         PG_SETMASK(&UnBlockSig);
2864
2865         errno = save_errno;
2866 }
2867
2868
2869 /*
2870  * Dummy signal handler
2871  *
2872  * We use this for signals that we don't actually use in the postmaster,
2873  * but we do use in backends.  If we SIG_IGN such signals in the postmaster,
2874  * then a newly started backend might drop a signal that arrives before it's
2875  * able to reconfigure its signal processing.  (See notes in postgres.c.)
2876  */
2877 static void
2878 dummy_handler(SIGNAL_ARGS)
2879 {
2880 }
2881
2882
2883 /*
2884  * CharRemap: given an int in range 0..61, produce textual encoding of it
2885  * per crypt(3) conventions.
2886  */
2887 static char
2888 CharRemap(long ch)
2889 {
2890         if (ch < 0)
2891                 ch = -ch;
2892         ch = ch % 62;
2893
2894         if (ch < 26)
2895                 return 'A' + ch;
2896
2897         ch -= 26;
2898         if (ch < 26)
2899                 return 'a' + ch;
2900
2901         ch -= 26;
2902         return '0' + ch;
2903 }
2904
2905 /*
2906  * RandomSalt
2907  */
2908 static void
2909 RandomSalt(char *cryptSalt, char *md5Salt)
2910 {
2911         long            rand = PostmasterRandom();
2912
2913         cryptSalt[0] = CharRemap(rand % 62);
2914         cryptSalt[1] = CharRemap(rand / 62);
2915
2916         /*
2917          * It's okay to reuse the first random value for one of the MD5 salt
2918          * bytes, since only one of the two salts will be sent to the client.
2919          * After that we need to compute more random bits.
2920          *
2921          * We use % 255, sacrificing one possible byte value, so as to ensure
2922          * that all bits of the random() value participate in the result.
2923          * While at it, add one to avoid generating any null bytes.
2924          */
2925         md5Salt[0] = (rand % 255) + 1;
2926         rand = PostmasterRandom();
2927         md5Salt[1] = (rand % 255) + 1;
2928         rand = PostmasterRandom();
2929         md5Salt[2] = (rand % 255) + 1;
2930         rand = PostmasterRandom();
2931         md5Salt[3] = (rand % 255) + 1;
2932 }
2933
2934 /*
2935  * PostmasterRandom
2936  */
2937 static long
2938 PostmasterRandom(void)
2939 {
2940         static bool initialized = false;
2941
2942         if (!initialized)
2943         {
2944                 Assert(random_seed != 0);
2945                 srandom(random_seed);
2946                 initialized = true;
2947         }
2948
2949         return random();
2950 }
2951
2952 /*
2953  * Count up number of child processes.
2954  */
2955 static int
2956 CountChildren(void)
2957 {
2958         Dlelem     *curr;
2959         Backend    *bp;
2960         int                     cnt = 0;
2961
2962         for (curr = DLGetHead(BackendList); curr; curr = DLGetSucc(curr))
2963         {
2964                 bp = (Backend *) DLE_VAL(curr);
2965                 if (bp->pid != MyProcPid)
2966                         cnt++;
2967         }
2968         /* Checkpoint and bgwriter will be in the list, discount them */
2969         if (CheckPointPID != 0)
2970                 cnt--;
2971         if (BgWriterPID != 0)
2972                 cnt--;
2973         return cnt;
2974 }
2975
2976 /*
2977  * Fire off a subprocess for startup/shutdown/checkpoint/bgwriter.
2978  *
2979  * Return value of SSDataBase is subprocess' PID, or 0 if failed to start subprocess
2980  * (0 is returned only for checkpoint/bgwriter cases).
2981  *
2982  * note: in the EXEC_BACKEND case, we delay the fork until argument list has been
2983  *      established
2984  */
2985 NON_EXEC_STATIC void
2986 SSDataBaseInit(int xlop)
2987 {
2988         const char *statmsg;
2989
2990         IsUnderPostmaster = true;               /* we are a postmaster subprocess
2991                                                                          * now */
2992
2993 #ifdef EXEC_BACKEND
2994         /* In EXEC case we will not have inherited these settings */
2995         IsPostmasterEnvironment = true;
2996         whereToSendOutput = None;
2997 #endif
2998
2999         MyProcPid = getpid();           /* reset MyProcPid */
3000
3001         /* Lose the postmaster's on-exit routines and port connections */
3002         on_exit_reset();
3003
3004         /*
3005          * Identify myself via ps
3006          */
3007         switch (xlop)
3008         {
3009                 case BS_XLOG_STARTUP:
3010                         statmsg = "startup subprocess";
3011                         break;
3012                 case BS_XLOG_CHECKPOINT:
3013                         statmsg = "checkpoint subprocess";
3014                         break;
3015                 case BS_XLOG_BGWRITER:
3016                         statmsg = "bgwriter subprocess";
3017                         break;
3018                 case BS_XLOG_SHUTDOWN:
3019                         statmsg = "shutdown subprocess";
3020                         break;
3021                 default:
3022                         statmsg = "??? subprocess";
3023                         break;
3024         }
3025         init_ps_display(statmsg, "", "");
3026         set_ps_display("");
3027 }
3028
3029
3030 static pid_t
3031 SSDataBase(int xlop)
3032 {
3033         pid_t           pid;
3034         Backend    *bn;
3035 #ifndef EXEC_BACKEND
3036 #ifdef LINUX_PROFILE
3037         struct itimerval prof_itimer;
3038 #endif
3039 #else
3040         char            idbuf[32];
3041         char            ddirbuf[MAXPGPATH];
3042 #endif
3043
3044         fflush(stdout);
3045         fflush(stderr);
3046
3047 #ifndef EXEC_BACKEND
3048 #ifdef LINUX_PROFILE
3049         /* see comments in BackendRun */
3050         getitimer(ITIMER_PROF, &prof_itimer);
3051 #endif
3052
3053 #ifdef __BEOS__
3054         /* Specific beos actions before backend startup */
3055         beos_before_backend_startup();
3056 #endif
3057
3058         /* Non EXEC_BACKEND case; fork here */
3059         if ((pid = fork()) == 0)        /* child */
3060 #endif
3061         {
3062                 char       *av[10];
3063                 int                     ac = 0;
3064                 char            nbbuf[32];
3065                 char            xlbuf[32];
3066
3067 #ifndef EXEC_BACKEND
3068 #ifdef LINUX_PROFILE
3069                 setitimer(ITIMER_PROF, &prof_itimer, NULL);
3070 #endif
3071
3072 #ifdef __BEOS__
3073                 /* Specific beos actions after backend startup */
3074                 beos_backend_startup();
3075 #endif
3076
3077                 /* Close the postmaster's sockets */
3078                 ClosePostmasterPorts(true);
3079
3080                 SSDataBaseInit(xlop);
3081 #else
3082                 if (!write_backend_variables(NULL))
3083                         return -1; /* log issued by write_backend_variables */
3084 #endif
3085
3086                 /* Set up command-line arguments for subprocess */
3087                 av[ac++] = "postgres";
3088
3089 #ifdef EXEC_BACKEND
3090                 av[ac++] = "-boot";
3091 #endif
3092                 snprintf(nbbuf, sizeof(nbbuf), "-B%d", NBuffers);
3093                 av[ac++] = nbbuf;
3094
3095                 snprintf(xlbuf, sizeof(xlbuf), "-x%d", xlop);
3096                 av[ac++] = xlbuf;
3097
3098 #ifdef EXEC_BACKEND
3099                 /* pass data dir before end of secure switches (-p) */
3100                 snprintf(ddirbuf, MAXPGPATH, "\"%s\"", DataDir);
3101                 av[ac++] = "-D";
3102                 av[ac++] = ddirbuf;
3103
3104                 /* and the backend identifier + dbname */
3105                 snprintf(idbuf, sizeof(idbuf), "-p%lu,template1", tmpBackendFileNum);
3106                 av[ac++] = idbuf;
3107 #else
3108                 av[ac++] = "-p";
3109                 av[ac++] = "template1";
3110 #endif
3111
3112                 av[ac] = NULL;
3113
3114                 Assert(ac < lengthof(av));
3115
3116 #ifdef EXEC_BACKEND
3117                 /* EXEC_BACKEND case; fork/exec here */
3118 #ifdef WIN32
3119                 pid = win32_forkexec(pg_pathname,av); /* logs on error */
3120 #else
3121                 if ((pid = fork()) == 0 && (execv(pg_pathname,av) == -1))
3122                 {
3123                         /* in child */
3124                         elog(ERROR,"unable to execv in SSDataBase: %m");
3125                         exit(0);
3126                 }
3127 #endif
3128 #else
3129                 BootstrapMain(ac, av);
3130                 ExitPostmaster(0);
3131 #endif
3132         }
3133
3134         /* in parent */
3135         if (pid < 0)
3136         {
3137 #ifndef EXEC_BACKEND
3138 #ifdef __BEOS__
3139                 /* Specific beos actions before backend startup */
3140                 beos_backend_startup_failed();
3141 #endif
3142 #endif
3143                 switch (xlop)
3144                 {
3145                         case BS_XLOG_STARTUP:
3146                                 ereport(LOG,
3147                                                 (errmsg("could not fork startup process: %m")));
3148                                 break;
3149                         case BS_XLOG_CHECKPOINT:
3150                                 ereport(LOG,
3151                                           (errmsg("could not fork checkpoint process: %m")));
3152                                 break;
3153                         case BS_XLOG_BGWRITER:
3154                                 ereport(LOG,
3155                                           (errmsg("could not fork bgwriter process: %m")));
3156                                 break;
3157                         case BS_XLOG_SHUTDOWN:
3158                                 ereport(LOG,
3159                                                 (errmsg("could not fork shutdown process: %m")));
3160                                 break;
3161                         default:
3162                                 ereport(LOG,
3163                                                 (errmsg("could not fork process: %m")));
3164                                 break;
3165                 }
3166
3167                 /*
3168                  * fork failure is fatal during startup/shutdown, but there's no
3169                  * need to choke if a routine checkpoint or starting a background
3170                  * writer fails.
3171                  */
3172                 if (xlop == BS_XLOG_CHECKPOINT)
3173                         return 0;
3174                 if (xlop == BS_XLOG_BGWRITER)
3175                         return 0;
3176                 ExitPostmaster(1);
3177         }
3178
3179         /*
3180          * The startup and shutdown processes are not considered normal
3181          * backends, but the checkpoint and bgwriter processes are.
3182          * They must be added to the list of backends.
3183          */
3184         if (xlop == BS_XLOG_CHECKPOINT || xlop == BS_XLOG_BGWRITER)
3185         {
3186                 if (!(bn = (Backend *) malloc(sizeof(Backend))))
3187                 {
3188                         ereport(LOG,
3189                                         (errcode(ERRCODE_OUT_OF_MEMORY),
3190                                          errmsg("out of memory")));
3191                         ExitPostmaster(1);
3192                 }
3193
3194                 bn->pid = pid;
3195                 bn->cancel_key = PostmasterRandom();
3196 #ifdef EXEC_BACKEND
3197                 ShmemBackendArrayAdd(bn);
3198 #endif
3199                 DLAddHead(BackendList, DLNewElem(bn));
3200
3201                 /*
3202                  * Since this code is executed periodically, it's a fine place to
3203                  * do other actions that should happen every now and then on no
3204                  * particular schedule.  Such as...
3205                  */
3206                 TouchSocketFile();
3207                 TouchSocketLockFile();
3208         }
3209
3210         return pid;
3211 }
3212
3213
3214 /*
3215  * Create the opts file
3216  */
3217 static bool
3218 CreateOptsFile(int argc, char *argv[])
3219 {
3220         char            fullprogname[MAXPGPATH];
3221         char            filename[MAXPGPATH];
3222         FILE       *fp;
3223         int                     i;
3224
3225         if (FindExec(fullprogname, argv[0], "postmaster") < 0)
3226         {
3227                 elog(LOG, "could not locate postmaster");
3228                 return false;
3229         }
3230
3231         snprintf(filename, sizeof(filename), "%s/postmaster.opts", DataDir);
3232
3233         if ((fp = fopen(filename, "w")) == NULL)
3234         {
3235                 elog(LOG, "could not create file \"%s\": %m", filename);
3236                 return false;
3237         }
3238
3239         fprintf(fp, "%s", fullprogname);
3240         for (i = 1; i < argc; i++)
3241                 fprintf(fp, " '%s'", argv[i]);
3242         fputs("\n", fp);
3243
3244         if (fclose(fp))
3245         {
3246                 elog(LOG, "could not write file \"%s\": %m", filename);
3247                 return false;
3248         }
3249
3250         return true;
3251 }
3252
3253 /*
3254  * This should be used only for reporting "interactive" errors (essentially,
3255  * bogus arguments on the command line).  Once the postmaster is launched,
3256  * use ereport.  In particular, don't use this for anything that occurs
3257  * after pmdaemonize.
3258  */
3259 static void
3260 postmaster_error(const char *fmt,...)
3261 {
3262         va_list         ap;
3263
3264         fprintf(stderr, "%s: ", progname);
3265         va_start(ap, fmt);
3266         vfprintf(stderr, gettext(fmt), ap);
3267         va_end(ap);
3268         fprintf(stderr, "\n");
3269 }
3270
3271
3272 #ifdef EXEC_BACKEND
3273
3274 /*
3275  * The following need to be available to the read/write_backend_variables
3276  * functions
3277  */
3278 #include "storage/spin.h"
3279 extern XLogRecPtr RedoRecPtr;
3280 extern XLogwrtResult LogwrtResult;
3281 extern slock_t *ShmemLock;
3282 extern slock_t *ShmemIndexLock;
3283 extern void *ShmemIndexAlloc;
3284 typedef struct LWLock LWLock;
3285 extern LWLock *LWLockArray;
3286 extern slock_t  *ProcStructLock;
3287 extern int      pgStatSock;
3288
3289 #define write_var(var,fp) fwrite((void*)&(var),sizeof(var),1,fp)
3290 #define read_var(var,fp)  fread((void*)&(var),sizeof(var),1,fp)
3291 #define get_tmp_backend_file_name(buf,id)       \
3292                 do {                                                            \
3293                         Assert(DataDir);                                \
3294                         sprintf((buf),                                  \
3295                                 "%s/%s/%s.backend_var.%lu",     \
3296                                 DataDir,                                        \
3297                                 PG_TEMP_FILES_DIR,                      \
3298                                 PG_TEMP_FILE_PREFIX,            \
3299                                 (id));                                          \
3300                 } while (0)
3301
3302 static bool
3303 write_backend_variables(Port *port)
3304 {
3305         char    filename[MAXPGPATH];
3306         FILE    *fp;
3307         get_tmp_backend_file_name(filename,++tmpBackendFileNum);
3308
3309         /* Open file */
3310         fp = AllocateFile(filename, PG_BINARY_W);
3311         if (!fp)
3312         {
3313                 /* As per OpenTemporaryFile... */
3314                 char dirname[MAXPGPATH];
3315                 sprintf(dirname,"%s/%s",DataDir,PG_TEMP_FILES_DIR);
3316                 mkdir(dirname, S_IRWXU);
3317
3318                 fp = AllocateFile(filename, PG_BINARY_W);
3319                 if (!fp)
3320                 {
3321                         ereport(ERROR,
3322                                 (errcode_for_file_access(),
3323                                 errmsg("could not write to file \"%s\": %m", filename)));
3324                         return false;
3325                 }
3326         }
3327
3328         /* Write vars */
3329         if (port)
3330         {
3331                 write_var(port->sock,fp);
3332                 write_var(port->proto,fp);
3333                 write_var(port->laddr,fp);
3334                 write_var(port->raddr,fp);
3335                 write_var(port->canAcceptConnections,fp);
3336                 write_var(port->cryptSalt,fp);
3337                 write_var(port->md5Salt,fp);
3338         }
3339         write_var(MyCancelKey,fp);
3340
3341         write_var(RedoRecPtr,fp);
3342         write_var(LogwrtResult,fp);
3343
3344         write_var(UsedShmemSegID,fp);
3345         write_var(UsedShmemSegAddr,fp);
3346
3347         write_var(ShmemLock,fp);
3348         write_var(ShmemIndexLock,fp);
3349         write_var(ShmemVariableCache,fp);
3350         write_var(ShmemIndexAlloc,fp);
3351         write_var(ShmemBackendArray,fp);
3352
3353         write_var(LWLockArray,fp);
3354         write_var(ProcStructLock,fp);
3355         write_var(pgStatSock,fp);
3356
3357         write_var(PreAuthDelay,fp);
3358         write_var(debug_flag,fp);
3359         write_var(PostmasterPid,fp);
3360
3361         /* Release file */
3362         if (FreeFile(fp))
3363         {
3364                 ereport(ERROR,
3365                                 (errcode_for_file_access(),
3366                                  errmsg("could not write to file \"%s\": %m", filename)));
3367                 return false;
3368         }
3369
3370         return true;
3371 }
3372
3373 void
3374 read_backend_variables(unsigned long id, Port *port)
3375 {
3376         char    filename[MAXPGPATH];
3377         FILE    *fp;
3378         get_tmp_backend_file_name(filename,id);
3379
3380         /* Open file */
3381         fp = AllocateFile(filename, PG_BINARY_R);
3382         if (!fp)
3383         {
3384                 ereport(ERROR,
3385                         (errcode_for_file_access(),
3386                         errmsg("could not read from backend_variables file \"%s\": %m", filename)));
3387                 return;
3388         }
3389
3390         /* Read vars */
3391         if (port)
3392         {
3393                 read_var(port->sock,fp);
3394                 read_var(port->proto,fp);
3395                 read_var(port->laddr,fp);
3396                 read_var(port->raddr,fp);
3397                 read_var(port->canAcceptConnections,fp);
3398                 read_var(port->cryptSalt,fp);
3399                 read_var(port->md5Salt,fp);
3400         }
3401         read_var(MyCancelKey,fp);
3402
3403         read_var(RedoRecPtr,fp);
3404         read_var(LogwrtResult,fp);
3405
3406         read_var(UsedShmemSegID,fp);
3407         read_var(UsedShmemSegAddr,fp);
3408
3409         read_var(ShmemLock,fp);
3410         read_var(ShmemIndexLock,fp);
3411         read_var(ShmemVariableCache,fp);
3412         read_var(ShmemIndexAlloc,fp);
3413         read_var(ShmemBackendArray,fp);
3414
3415         read_var(LWLockArray,fp);
3416         read_var(ProcStructLock,fp);
3417         read_var(pgStatSock,fp);
3418
3419         read_var(PreAuthDelay,fp);
3420         read_var(debug_flag,fp);
3421         read_var(PostmasterPid,fp);
3422
3423         /* Release file */
3424         FreeFile(fp);
3425         if (unlink(filename) != 0)
3426                 ereport(WARNING,
3427                                 (errcode_for_file_access(),
3428                                  errmsg("could not remove file \"%s\": %m", filename)));
3429 }
3430
3431
3432 size_t ShmemBackendArraySize(void)
3433 {
3434         return (NUM_BACKENDARRAY_ELEMS*sizeof(Backend));
3435 }
3436
3437 void ShmemBackendArrayAllocation(void)
3438 {
3439         size_t size = ShmemBackendArraySize();
3440         ShmemBackendArray = (Backend*)ShmemAlloc(size);
3441         memset(ShmemBackendArray, 0, size);
3442 }
3443
3444 static void ShmemBackendArrayAdd(Backend *bn)
3445 {
3446         int i;
3447         for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++)
3448         {
3449                 /* Find an empty slot */
3450                 if (ShmemBackendArray[i].pid == 0)
3451                 {
3452                         ShmemBackendArray[i] = *bn;
3453                         return;
3454                 }
3455         }
3456
3457         ereport(FATAL,
3458                         (errmsg_internal("unable to add backend entry")));
3459 }
3460
3461 static void ShmemBackendArrayRemove(pid_t pid)
3462 {
3463         int i;
3464         for (i = 0; i < NUM_BACKENDARRAY_ELEMS; i++)
3465         {
3466                 if (ShmemBackendArray[i].pid == pid)
3467                 {
3468                         /* Mark the slot as empty */
3469                         ShmemBackendArray[i].pid = 0;
3470                         return;
3471                 }
3472         }
3473
3474         ereport(WARNING,
3475                         (errmsg_internal("unable to find backend entry with pid %d",
3476                                                          pid)));
3477 }
3478
3479 #endif
3480
3481 #ifdef WIN32
3482
3483 pid_t win32_forkexec(const char* path, char *argv[])
3484 {
3485         STARTUPINFO si;
3486         PROCESS_INFORMATION pi;
3487         char *p;
3488         int i;
3489         char cmdLine[MAXPGPATH];
3490         HANDLE childHandleCopy;
3491         HANDLE waiterThread;
3492
3493         /* Format the cmd line */
3494         snprintf(cmdLine,sizeof(cmdLine),"\"%s\"",path);
3495         i = 0;
3496         while (argv[++i] != NULL)
3497         {
3498                 /* FIXME: [fork/exec] some strlen checks might be prudent here */
3499                 strcat(cmdLine," ");
3500                 strcat(cmdLine,argv[i]);
3501         }
3502
3503         /*
3504          * The following snippet can disappear when we consistently
3505          * use forward slashes.
3506          */
3507         p = cmdLine;
3508         while (*(p++) != '\0')
3509                 if (*p == '/') *p = '\\';
3510
3511         memset(&pi,0,sizeof(pi));
3512         memset(&si,0,sizeof(si));
3513         si.cb = sizeof(si);
3514         if (!CreateProcess(NULL,cmdLine,NULL,NULL,TRUE,0,NULL,NULL,&si,&pi))
3515         {
3516                 elog(ERROR,"CreateProcess call failed (%i): %m",(int)GetLastError());
3517                 return -1;
3518         }
3519
3520         if (!IsUnderPostmaster)
3521                 /* We are the Postmaster creating a child... */
3522                 win32_AddChild(pi.dwProcessId,pi.hProcess);
3523
3524         if (!DuplicateHandle(GetCurrentProcess(),
3525                                                  pi.hProcess,
3526                                                  GetCurrentProcess(),
3527                                                  &childHandleCopy,
3528                                                  0,
3529                                                  FALSE,
3530                                                  DUPLICATE_SAME_ACCESS))
3531                 ereport(FATAL,
3532                                 (errmsg_internal("failed to duplicate child handle: %i",(int)GetLastError())));
3533         waiterThread = CreateThread(NULL, 64*1024, win32_sigchld_waiter, (LPVOID)childHandleCopy, 0, NULL);
3534         if (!waiterThread)
3535                 ereport(FATAL,
3536                                 (errmsg_internal("failed to create sigchld waiter thread: %i",(int)GetLastError())));
3537         CloseHandle(waiterThread);
3538
3539         if (IsUnderPostmaster)
3540                 CloseHandle(pi.hProcess);
3541         CloseHandle(pi.hThread);
3542
3543         return pi.dwProcessId;
3544 }
3545
3546 /*
3547  * Note: The following three functions must not be interrupted (eg. by signals).
3548  *  As the Postgres Win32 signalling architecture (currently) requires polling,
3549  *  or APC checking functions which aren't used here, this is not an issue.
3550  *
3551  *  We keep two separate arrays, instead of a single array of pid/HANDLE structs,
3552  *  to avoid having to re-create a handle array for WaitForMultipleObjects on
3553  *  each call to win32_waitpid.
3554  */
3555
3556 static void win32_AddChild(pid_t pid, HANDLE handle)
3557 {
3558         Assert(win32_childPIDArray && win32_childHNDArray);
3559         if (win32_numChildren < NUM_BACKENDARRAY_ELEMS)
3560         {
3561                 win32_childPIDArray[win32_numChildren] = pid;
3562                 win32_childHNDArray[win32_numChildren] = handle;
3563                 ++win32_numChildren;
3564         }
3565         else
3566                 ereport(FATAL,
3567                                 (errmsg_internal("unable to add child entry with pid %lu",
3568                                                                  pid)));
3569 }
3570
3571 static void win32_RemoveChild(pid_t pid)
3572 {
3573         int i;
3574         Assert(win32_childPIDArray && win32_childHNDArray);
3575
3576         for (i = 0; i < win32_numChildren; i++)
3577         {
3578                 if (win32_childPIDArray[i] == pid)
3579                 {
3580                         CloseHandle(win32_childHNDArray[i]);
3581
3582                         /* Swap last entry into the "removed" one */
3583                         --win32_numChildren;
3584                         win32_childPIDArray[i] = win32_childPIDArray[win32_numChildren];
3585                         win32_childHNDArray[i] = win32_childHNDArray[win32_numChildren];
3586                         return;
3587                 }
3588         }
3589
3590         ereport(WARNING,
3591                         (errmsg_internal("unable to find child entry with pid %lu",
3592                                                          pid)));
3593 }
3594
3595 static pid_t win32_waitpid(int *exitstatus)
3596 {
3597         Assert(win32_childPIDArray && win32_childHNDArray);
3598         elog(DEBUG3,"waiting on %lu children",win32_numChildren);
3599
3600         if (win32_numChildren > 0)
3601         {
3602                 /*
3603                  * Note: Do NOT use WaitForMultipleObjectsEx, as we don't
3604                  * want to run queued APCs here.
3605                  */
3606                 int index;
3607                 DWORD exitCode;
3608                 DWORD ret = WaitForMultipleObjects(win32_numChildren,win32_childHNDArray,FALSE,0);
3609
3610                 switch (ret)
3611                 {
3612                         case WAIT_FAILED:
3613                                 ereport(ERROR,
3614                                                 (errmsg_internal("failed to wait on %lu children: %i",
3615                                                                                  win32_numChildren,(int)GetLastError())));
3616                                 /* Fall through to WAIT_TIMEOUTs return */
3617
3618                         case WAIT_TIMEOUT:
3619                                 /* No children have finished */
3620                                 return -1;
3621
3622                         default:
3623                                 /* Get the exit code, and return the PID of, the respective process */
3624                                 index = ret-WAIT_OBJECT_0;
3625                                 Assert(index >= 0 && index < win32_numChildren);
3626                                 if (!GetExitCodeProcess(win32_childHNDArray[index],&exitCode))
3627                                         /*
3628                                          * If we get this far, this should never happen, but, then again...
3629                                          * No choice other than to assume a catastrophic failure.
3630                                          */
3631                                         ereport(FATAL,
3632                                                         (errmsg_internal("failed to get exit code for child %lu",
3633                                                                                          win32_childPIDArray[index])));
3634                                 *exitstatus = (int)exitCode;
3635                                 return win32_childPIDArray[index];
3636                 }
3637         }
3638
3639         /* No children */
3640         return -1;
3641 }
3642
3643 /* Note! Code belows executes on separate threads, one for
3644    each child process created */
3645 static DWORD WINAPI win32_sigchld_waiter(LPVOID param) {
3646         HANDLE procHandle = (HANDLE)param;
3647
3648         DWORD r = WaitForSingleObject(procHandle, INFINITE);
3649         if (r == WAIT_OBJECT_0)
3650                 pg_queue_signal(SIGCHLD);
3651         else
3652                 fprintf(stderr,"ERROR: Failed to wait on child process handle: %i\n",(int)GetLastError());
3653         CloseHandle(procHandle);
3654         return 0;
3655 }
3656
3657 #endif