granicus.if.org Git - postgresql/blob - contrib/pg_archivecleanup/pg_archivecleanup.c

   1 /*
   2  * contrib/pg_archivecleanup/pg_archivecleanup.c
   3  *
   4  * pg_archivecleanup.c
   5  *
   6  * Production-ready example of an archive_cleanup_command
   7  * used to clean an archive when using standby_mode = on in 9.0
   8  * or for standalone use for any version of PostgreSQL 8.0+.
   9  *
  10  * Original author:             Simon Riggs  simon@2ndquadrant.com
  11  * Current maintainer:  Simon Riggs
  12  */
  13 #include "postgres_fe.h"
  14
  15 #include <ctype.h>
  16 #include <dirent.h>
  17 #include <sys/stat.h>
  18 #include <fcntl.h>
  19 #include <signal.h>
  20 #include <sys/time.h>
  21
  22 #include "pg_getopt.h"
  23
  24 const char *progname;
  25
  26 /* Options and defaults */
  27 bool            debug = false;          /* are we debugging? */
  28 bool            dryrun = false;         /* are we performing a dry-run operation? */
  29 char       *additional_ext = NULL;              /* Extension to remove from filenames */
  30
  31 char       *archiveLocation;    /* where to find the archive? */
  32 char       *restartWALFileName; /* the file from which we can restart restore */
  33 char            WALFilePath[MAXPGPATH];         /* the file path including archive */
  34 char            exclusiveCleanupFileName[MAXPGPATH];            /* the oldest file we
  35                                                                                                                  * want to remain in
  36                                                                                                                  * archive */
  37
  38
  39 /* =====================================================================
  40  *
  41  *                Customizable section
  42  *
  43  * =====================================================================
  44  *
  45  *      Currently, this section assumes that the Archive is a locally
  46  *      accessible directory. If you want to make other assumptions,
  47  *      such as using a vendor-specific archive and access API, these
  48  *      routines are the ones you'll need to change. You're
  49  *      enouraged to submit any changes to pgsql-hackers@postgresql.org
  50  *      or personally to the current maintainer. Those changes may be
  51  *      folded in to later versions of this program.
  52  */
  53
  54 #define XLOG_DATA_FNAME_LEN             24
  55 /* Reworked from access/xlog_internal.h */
  56 #define XLogFileName(fname, tli, log, seg)      \
  57         snprintf(fname, XLOG_DATA_FNAME_LEN + 1, "%08X%08X%08X", tli, log, seg)
  58 #define XLOG_BACKUP_FNAME_LEN   40
  59
  60 /*
  61  *      Initialize allows customized commands into the archive cleanup program.
  62  *
  63  *      You may wish to add code to check for tape libraries, etc..
  64  */
  65 static void
  66 Initialize(void)
  67 {
  68         /*
  69          * This code assumes that archiveLocation is a directory, so we use stat
  70          * to test if it's accessible.
  71          */
  72         struct stat stat_buf;
  73
  74         if (stat(archiveLocation, &stat_buf) != 0 ||
  75                 !S_ISDIR(stat_buf.st_mode))
  76         {
  77                 fprintf(stderr, "%s: archive location \"%s\" does not exist\n",
  78                                 progname, archiveLocation);
  79                 exit(2);
  80         }
  81 }
  82
  83 static void
  84 TrimExtension(char *filename, char *extension)
  85 {
  86         int                     flen;
  87         int                     elen;
  88
  89         if (extension == NULL)
  90                 return;
  91
  92         elen = strlen(extension);
  93         flen = strlen(filename);
  94
  95         if (flen > elen && strcmp(filename + flen - elen, extension) == 0)
  96                 filename[flen - elen] = '\0';
  97 }
  98
  99 static void
 100 CleanupPriorWALFiles(void)
 101 {
 102         int                     rc;
 103         DIR                *xldir;
 104         struct dirent *xlde;
 105         char            walfile[MAXPGPATH];
 106
 107         if ((xldir = opendir(archiveLocation)) != NULL)
 108         {
 109                 while ((xlde = readdir(xldir)) != NULL)
 110                 {
 111                         strncpy(walfile, xlde->d_name, MAXPGPATH);
 112                         TrimExtension(walfile, additional_ext);
 113
 114                         /*
 115                          * We ignore the timeline part of the XLOG segment identifiers in
 116                          * deciding whether a segment is still needed.  This ensures that
 117                          * we won't prematurely remove a segment from a parent timeline.
 118                          * We could probably be a little more proactive about removing
 119                          * segments of non-parent timelines, but that would be a whole lot
 120                          * more complicated.
 121                          *
 122                          * We use the alphanumeric sorting property of the filenames to
 123                          * decide which ones are earlier than the exclusiveCleanupFileName
 124                          * file. Note that this means files are not removed in the order
 125                          * they were originally written, in case this worries you.
 126                          */
 127                         if (strlen(walfile) == XLOG_DATA_FNAME_LEN &&
 128                                 strspn(walfile, "0123456789ABCDEF") == XLOG_DATA_FNAME_LEN &&
 129                                 strcmp(walfile + 8, exclusiveCleanupFileName + 8) < 0)
 130                         {
 131                                 /*
 132                                  * Use the original file name again now, including any
 133                                  * extension that might have been chopped off before testing
 134                                  * the sequence.
 135                                  */
 136                                 snprintf(WALFilePath, MAXPGPATH, "%s/%s",
 137                                                  archiveLocation, xlde->d_name);
 138
 139                                 if (dryrun)
 140                                 {
 141                                         /*
 142                                          * Prints the name of the file to be removed and skips the
 143                                          * actual removal.      The regular printout is so that the
 144                                          * user can pipe the output into some other program.
 145                                          */
 146                                         printf("%s\n", WALFilePath);
 147                                         if (debug)
 148                                                 fprintf(stderr,
 149                                                                 "%s: file \"%s\" would be removed\n",
 150                                                                 progname, WALFilePath);
 151                                         continue;
 152                                 }
 153
 154                                 if (debug)
 155                                         fprintf(stderr, "%s: removing file \"%s\"\n",
 156                                                         progname, WALFilePath);
 157
 158                                 rc = unlink(WALFilePath);
 159                                 if (rc != 0)
 160                                 {
 161                                         fprintf(stderr, "%s: ERROR: could not remove file \"%s\": %s\n",
 162                                                         progname, WALFilePath, strerror(errno));
 163                                         break;
 164                                 }
 165                         }
 166                 }
 167                 closedir(xldir);
 168         }
 169         else
 170                 fprintf(stderr, "%s: could not open archive location \"%s\": %s\n",
 171                                 progname, archiveLocation, strerror(errno));
 172 }
 173
 174 /*
 175  * SetWALFileNameForCleanup()
 176  *
 177  *        Set the earliest WAL filename that we want to keep on the archive
 178  *        and decide whether we need_cleanup
 179  */
 180 static void
 181 SetWALFileNameForCleanup(void)
 182 {
 183         bool            fnameOK = false;
 184
 185         TrimExtension(restartWALFileName, additional_ext);
 186
 187         /*
 188          * If restartWALFileName is a WAL file name then just use it directly. If
 189          * restartWALFileName is a .backup filename, make sure we use the prefix
 190          * of the filename, otherwise we will remove wrong files since
 191          * 000000010000000000000010.00000020.backup is after
 192          * 000000010000000000000010.
 193          */
 194         if (strlen(restartWALFileName) == XLOG_DATA_FNAME_LEN &&
 195                 strspn(restartWALFileName, "0123456789ABCDEF") == XLOG_DATA_FNAME_LEN)
 196         {
 197                 strcpy(exclusiveCleanupFileName, restartWALFileName);
 198                 fnameOK = true;
 199         }
 200         else if (strlen(restartWALFileName) == XLOG_BACKUP_FNAME_LEN)
 201         {
 202                 int                     args;
 203                 uint32          tli = 1,
 204                                         log = 0,
 205                                         seg = 0,
 206                                         offset = 0;
 207
 208                 args = sscanf(restartWALFileName, "%08X%08X%08X.%08X.backup", &tli, &log, &seg, &offset);
 209                 if (args == 4)
 210                 {
 211                         fnameOK = true;
 212
 213                         /*
 214                          * Use just the prefix of the filename, ignore everything after
 215                          * first period
 216                          */
 217                         XLogFileName(exclusiveCleanupFileName, tli, log, seg);
 218                 }
 219         }
 220
 221         if (!fnameOK)
 222         {
 223                 fprintf(stderr, "%s: invalid filename input\n", progname);
 224                 fprintf(stderr, "Try \"%s --help\" for more information.\n", progname);
 225                 exit(2);
 226         }
 227 }
 228
 229 /* =====================================================================
 230  *                End of Customizable section
 231  * =====================================================================
 232  */
 233
 234 static void
 235 usage(void)
 236 {
 237         printf("%s removes older WAL files from PostgreSQL archives.\n\n", progname);
 238         printf("Usage:\n");
 239         printf("  %s [OPTION]... ARCHIVELOCATION OLDESTKEPTWALFILE\n", progname);
 240         printf("\nOptions:\n");
 241         printf("  -d             generate debug output (verbose mode)\n");
 242         printf("  -n             dry run, show the names of the files that would be removed\n");
 243         printf("  -V, --version  output version information, then exit\n");
 244         printf("  -x EXT         clean up files if they have this extension\n");
 245         printf("  -?, --help     show this help, then exit\n");
 246         printf("\n"
 247                    "For use as archive_cleanup_command in recovery.conf when standby_mode = on:\n"
 248                    "  archive_cleanup_command = 'pg_archivecleanup [OPTION]... ARCHIVELOCATION %%r'\n"
 249                    "e.g.\n"
 250                    "  archive_cleanup_command = 'pg_archivecleanup /mnt/server/archiverdir %%r'\n");
 251         printf("\n"
 252                    "Or for use as a standalone archive cleaner:\n"
 253                    "e.g.\n"
 254                    "  pg_archivecleanup /mnt/server/archiverdir 000000010000000000000010.00000020.backup\n");
 255         printf("\nReport bugs to <pgsql-bugs@postgresql.org>.\n");
 256 }
 257
 258 /*------------ MAIN ----------------------------------------*/
 259 int
 260 main(int argc, char **argv)
 261 {
 262         int                     c;
 263
 264         progname = get_progname(argv[0]);
 265
 266         if (argc > 1)
 267         {
 268                 if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
 269                 {
 270                         usage();
 271                         exit(0);
 272                 }
 273                 if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
 274                 {
 275                         puts("pg_archivecleanup (PostgreSQL) " PG_VERSION);
 276                         exit(0);
 277                 }
 278         }
 279
 280         while ((c = getopt(argc, argv, "x:dn")) != -1)
 281         {
 282                 switch (c)
 283                 {
 284                         case 'd':                       /* Debug mode */
 285                                 debug = true;
 286                                 break;
 287                         case 'n':                       /* Dry-Run mode */
 288                                 dryrun = true;
 289                                 break;
 290                         case 'x':
 291                                 additional_ext = strdup(optarg);                /* Extension to remove
 292                                                                                                                  * from xlogfile names */
 293                                 break;
 294                         default:
 295                                 fprintf(stderr, "Try \"%s --help\" for more information.\n", progname);
 296                                 exit(2);
 297                                 break;
 298                 }
 299         }
 300
 301         /*
 302          * We will go to the archiveLocation to check restartWALFileName.
 303          * restartWALFileName may not exist anymore, which would not be an error,
 304          * so we separate the archiveLocation and restartWALFileName so we can
 305          * check separately whether archiveLocation exists, if not that is an
 306          * error
 307          */
 308         if (optind < argc)
 309         {
 310                 archiveLocation = argv[optind];
 311                 optind++;
 312         }
 313         else
 314         {
 315                 fprintf(stderr, "%s: must specify archive location\n", progname);
 316                 fprintf(stderr, "Try \"%s --help\" for more information.\n", progname);
 317                 exit(2);
 318         }
 319
 320         if (optind < argc)
 321         {
 322                 restartWALFileName = argv[optind];
 323                 optind++;
 324         }
 325         else
 326         {
 327                 fprintf(stderr, "%s: must specify restartfilename\n", progname);
 328                 fprintf(stderr, "Try \"%s --help\" for more information.\n", progname);
 329                 exit(2);
 330         }
 331
 332         if (optind < argc)
 333         {
 334                 fprintf(stderr, "%s: too many parameters\n", progname);
 335                 fprintf(stderr, "Try \"%s --help\" for more information.\n", progname);
 336                 exit(2);
 337         }
 338
 339         /*
 340          * Check archive exists and other initialization if required.
 341          */
 342         Initialize();
 343
 344         /*
 345          * Check filename is a valid name, then process to find cut-off
 346          */
 347         SetWALFileNameForCleanup();
 348
 349         if (debug)
 350         {
 351                 snprintf(WALFilePath, MAXPGPATH, "%s/%s",
 352                                  archiveLocation, exclusiveCleanupFileName);
 353                 fprintf(stderr, "%s: keep WAL file \"%s\" and later\n",
 354                                 progname, WALFilePath);
 355         }
 356
 357         /*
 358          * Remove WAL files older than cut-off
 359          */
 360         CleanupPriorWALFiles();
 361
 362         exit(0);
 363 }