/*------------------------------------------------------------------------- * * miscinit.c * miscellaneous initialization support stuff * * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION * $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.140 2005/06/07 01:36:40 momjian Exp $ * *------------------------------------------------------------------------- */ #include "postgres.h" #include #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_UTIME_H #include #endif #include "catalog/pg_shadow.h" #include "libpq/libpq-be.h" #include "miscadmin.h" #include "storage/fd.h" #include "storage/ipc.h" #include "storage/pg_shmem.h" #include "utils/builtins.h" #include "utils/guc.h" #include "utils/lsyscache.h" #include "utils/syscache.h" ProcessingMode Mode = InitProcessing; /* Note: we rely on these to initialize as zeroes */ static char directoryLockFile[MAXPGPATH]; static char socketLockFile[MAXPGPATH]; /* ---------------------------------------------------------------- * ignoring system indexes support stuff * * NOTE: "ignoring system indexes" means we do not use the system indexes * for lookups (either in hardwired catalog accesses or in planner-generated * plans). We do, however, still update the indexes when a catalog * modification is made. * ---------------------------------------------------------------- */ static bool isIgnoringSystemIndexes = false; /* * IsIgnoringSystemIndexes * True if ignoring system indexes. */ bool IsIgnoringSystemIndexes(void) { return isIgnoringSystemIndexes; } /* * IgnoreSystemIndexes * Set true or false whether PostgreSQL ignores system indexes. */ void IgnoreSystemIndexes(bool mode) { isIgnoringSystemIndexes = mode; } /* ---------------------------------------------------------------- * system index reindexing support * * When we are busy reindexing a system index, this code provides support * for preventing catalog lookups from using that index. * ---------------------------------------------------------------- */ static Oid currentlyReindexedHeap = InvalidOid; static Oid currentlyReindexedIndex = InvalidOid; /* * ReindexIsProcessingHeap * True if heap specified by OID is currently being reindexed. */ bool ReindexIsProcessingHeap(Oid heapOid) { return heapOid == currentlyReindexedHeap; } /* * ReindexIsProcessingIndex * True if index specified by OID is currently being reindexed. */ bool ReindexIsProcessingIndex(Oid indexOid) { return indexOid == currentlyReindexedIndex; } /* * SetReindexProcessing * Set flag that specified heap/index are being reindexed. */ void SetReindexProcessing(Oid heapOid, Oid indexOid) { Assert(OidIsValid(heapOid) && OidIsValid(indexOid)); /* Reindexing is not re-entrant. */ if (OidIsValid(currentlyReindexedIndex)) elog(ERROR, "cannot reindex while reindexing"); currentlyReindexedHeap = heapOid; currentlyReindexedIndex = indexOid; } /* * ResetReindexProcessing * Unset reindexing status. */ void ResetReindexProcessing(void) { currentlyReindexedHeap = InvalidOid; currentlyReindexedIndex = InvalidOid; } /* ---------------------------------------------------------------- * database path / name support stuff * ---------------------------------------------------------------- */ void SetDatabasePath(const char *path) { if (DatabasePath) { free(DatabasePath); DatabasePath = NULL; } /* use strdup since this is done before memory contexts are set up */ if (path) { DatabasePath = strdup(path); AssertState(DatabasePath); } } /* * Set data directory, but make sure it's an absolute path. Use this, * never set DataDir directly. */ void SetDataDir(const char *dir) { char *new; AssertArg(dir); /* If presented path is relative, convert to absolute */ new = make_absolute_path(dir); if (DataDir) free(DataDir); DataDir = new; } /* * If the given pathname isn't already absolute, make it so, interpreting * it relative to the current working directory. * * Also canonicalizes the path. The result is always a malloc'd copy. * * Note: it is probably unwise to use this in running backends, since they * have chdir'd to a database-specific subdirectory; the results would not be * consistent across backends. Currently this is used only during postmaster * or standalone-backend startup. */ char * make_absolute_path(const char *path) { char *new; /* Returning null for null input is convenient for some callers */ if (path == NULL) return NULL; if (!is_absolute_path(path)) { char *buf; size_t buflen; buflen = MAXPGPATH; for (;;) { buf = malloc(buflen); if (!buf) ereport(FATAL, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); if (getcwd(buf, buflen)) break; else if (errno == ERANGE) { free(buf); buflen *= 2; continue; } else { free(buf); elog(FATAL, "could not get current working directory: %m"); } } new = malloc(strlen(buf) + strlen(path) + 2); if (!new) ereport(FATAL, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); sprintf(new, "%s/%s", buf, path); free(buf); } else { new = strdup(path); if (!new) ereport(FATAL, (errcode(ERRCODE_OUT_OF_MEMORY), errmsg("out of memory"))); } /* Make sure punctuation is canonical, too */ canonicalize_path(new); return new; } /* ---------------------------------------------------------------- * User ID things * * The authenticated user is determined at connection start and never * changes. The session user can be changed only by SET SESSION * AUTHORIZATION. The current user may change when "setuid" functions * are implemented. Conceptually there is a stack, whose bottom * is the session user. You are yourself responsible to save and * restore the current user id if you need to change it. * ---------------------------------------------------------------- */ static AclId AuthenticatedUserId = 0; static AclId SessionUserId = 0; static AclId CurrentUserId = 0; static bool AuthenticatedUserIsSuperuser = false; /* * This function is relevant for all privilege checks. */ AclId GetUserId(void) { AssertState(AclIdIsValid(CurrentUserId)); return CurrentUserId; } void SetUserId(AclId newid) { AssertArg(AclIdIsValid(newid)); CurrentUserId = newid; } /* * This value is only relevant for informational purposes. */ AclId GetSessionUserId(void) { AssertState(AclIdIsValid(SessionUserId)); return SessionUserId; } void SetSessionUserId(AclId newid) { AssertArg(AclIdIsValid(newid)); SessionUserId = newid; /* Current user defaults to session user. */ if (!AclIdIsValid(CurrentUserId)) CurrentUserId = newid; } void InitializeSessionUserId(const char *username) { HeapTuple userTup; Datum datum; bool isnull; AclId usesysid; /* * Don't do scans if we're bootstrapping, none of the system catalogs * exist yet, and they should be owned by postgres anyway. */ AssertState(!IsBootstrapProcessingMode()); /* call only once */ AssertState(!OidIsValid(AuthenticatedUserId)); userTup = SearchSysCache(SHADOWNAME, PointerGetDatum(username), 0, 0, 0); if (!HeapTupleIsValid(userTup)) ereport(FATAL, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("user \"%s\" does not exist", username))); usesysid = ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid; AuthenticatedUserId = usesysid; AuthenticatedUserIsSuperuser = ((Form_pg_shadow) GETSTRUCT(userTup))->usesuper; SetSessionUserId(usesysid); /* sets CurrentUserId too */ /* Record username and superuser status as GUC settings too */ SetConfigOption("session_authorization", username, PGC_BACKEND, PGC_S_OVERRIDE); SetConfigOption("is_superuser", AuthenticatedUserIsSuperuser ? "on" : "off", PGC_INTERNAL, PGC_S_OVERRIDE); /* * Set up user-specific configuration variables. This is a good place * to do it so we don't have to read pg_shadow twice during session * startup. */ datum = SysCacheGetAttr(SHADOWNAME, userTup, Anum_pg_shadow_useconfig, &isnull); if (!isnull) { ArrayType *a = DatumGetArrayTypeP(datum); ProcessGUCArray(a, PGC_S_USER); } ReleaseSysCache(userTup); } void InitializeSessionUserIdStandalone(void) { /* This function should only be called in a single-user backend. */ AssertState(!IsUnderPostmaster); /* call only once */ AssertState(!OidIsValid(AuthenticatedUserId)); AuthenticatedUserId = BOOTSTRAP_USESYSID; AuthenticatedUserIsSuperuser = true; SetSessionUserId(BOOTSTRAP_USESYSID); } /* * Change session auth ID while running * * Only a superuser may set auth ID to something other than himself. Note * that in case of multiple SETs in a single session, the original userid's * superuserness is what matters. But we set the GUC variable is_superuser * to indicate whether the *current* session userid is a superuser. */ void SetSessionAuthorization(AclId userid, bool is_superuser) { /* Must have authenticated already, else can't make permission check */ AssertState(AclIdIsValid(AuthenticatedUserId)); if (userid != AuthenticatedUserId && !AuthenticatedUserIsSuperuser) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("permission denied to set session authorization"))); SetSessionUserId(userid); SetUserId(userid); SetConfigOption("is_superuser", is_superuser ? "on" : "off", PGC_INTERNAL, PGC_S_OVERRIDE); } /* * Get user name from user id */ char * GetUserNameFromId(AclId userid) { HeapTuple tuple; char *result; tuple = SearchSysCache(SHADOWSYSID, ObjectIdGetDatum(userid), 0, 0, 0); if (!HeapTupleIsValid(tuple)) ereport(ERROR, (errcode(ERRCODE_UNDEFINED_OBJECT), errmsg("invalid user ID: %d", userid))); result = pstrdup(NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename)); ReleaseSysCache(tuple); return result; } /*------------------------------------------------------------------------- * Interlock-file support * * These routines are used to create both a data-directory lockfile * ($DATADIR/postmaster.pid) and a Unix-socket-file lockfile ($SOCKFILE.lock). * Both kinds of files contain the same info: * * Owning process' PID * Data directory path * * By convention, the owning process' PID is negated if it is a standalone * backend rather than a postmaster. This is just for informational purposes. * The path is also just for informational purposes (so that a socket lockfile * can be more easily traced to the associated postmaster). * * A data-directory lockfile can optionally contain a third line, containing * the key and ID for the shared memory block used by this postmaster. * * On successful lockfile creation, a proc_exit callback to remove the * lockfile is automatically created. *------------------------------------------------------------------------- */ /* * proc_exit callback to remove a lockfile. */ static void UnlinkLockFile(int status, Datum filename) { char *fname = (char *) DatumGetPointer(filename); if (fname != NULL) { if (unlink(fname) != 0) { /* Should we complain if the unlink fails? */ } free(fname); } } /* * Create a lockfile. * * filename is the name of the lockfile to create. * amPostmaster is used to determine how to encode the output PID. * isDDLock and refName are used to determine what error message to produce. */ static void CreateLockFile(const char *filename, bool amPostmaster, bool isDDLock, const char *refName) { int fd; char buffer[MAXPGPATH + 100]; int ntries; int len; int encoded_pid; pid_t other_pid; pid_t my_pid = getpid(); /* * We need a loop here because of race conditions. But don't loop * forever (for example, a non-writable $PGDATA directory might cause * a failure that won't go away). 100 tries seems like plenty. */ for (ntries = 0;; ntries++) { /* * Try to create the lock file --- O_EXCL makes this atomic. * * Think not to make the file protection weaker than 0600. See * comments below. */ fd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600); if (fd >= 0) break; /* Success; exit the retry loop */ /* * Couldn't create the pid file. Probably it already exists. */ if ((errno != EEXIST && errno != EACCES) || ntries > 100) ereport(FATAL, (errcode_for_file_access(), errmsg("could not create lock file \"%s\": %m", filename))); /* * Read the file to get the old owner's PID. Note race condition * here: file might have been deleted since we tried to create it. */ fd = open(filename, O_RDONLY, 0600); if (fd < 0) { if (errno == ENOENT) continue; /* race condition; try again */ ereport(FATAL, (errcode_for_file_access(), errmsg("could not open lock file \"%s\": %m", filename))); } if ((len = read(fd, buffer, sizeof(buffer) - 1)) < 0) ereport(FATAL, (errcode_for_file_access(), errmsg("could not read lock file \"%s\": %m", filename))); close(fd); buffer[len] = '\0'; encoded_pid = atoi(buffer); /* if pid < 0, the pid is for postgres, not postmaster */ other_pid = (pid_t) (encoded_pid < 0 ? -encoded_pid : encoded_pid); if (other_pid <= 0) elog(FATAL, "bogus data in lock file \"%s\"", filename); /* * Check to see if the other process still exists * * If the PID in the lockfile is our own PID or our parent's PID, * then the file must be stale (probably left over from a previous * system boot cycle). We need this test because of the likelihood * that a reboot will assign exactly the same PID as we had in the * previous reboot. Also, if there is just one more process launch * in this reboot than in the previous one, the lockfile might mention * our parent's PID. We can reject that since we'd never be launched * directly by a competing postmaster. We can't detect grandparent * processes unfortunately, but if the init script is written carefully * then all but the immediate parent shell will be root-owned processes * and so the kill test will fail with EPERM. * * We can treat the EPERM-error case as okay because that error implies * that the existing process has a different userid than we do, which * means it cannot be a competing postmaster. A postmaster cannot * successfully attach to a data directory owned by a userid other * than its own. (This is now checked directly in checkDataDir(), * but has been true for a long time because of the restriction that * the data directory isn't group- or world-accessible.) Also, * since we create the lockfiles mode 600, we'd have failed above * if the lockfile belonged to another userid --- which means that * whatever process kill() is reporting about isn't the one that * made the lockfile. (NOTE: this last consideration is the only * one that keeps us from blowing away a Unix socket file belonging * to an instance of Postgres being run by someone else, at least * on machines where /tmp hasn't got a stickybit.) * * Windows hasn't got getppid(), but doesn't need it since it's not * using real kill() either... * * Normally kill() will fail with ESRCH if the given PID doesn't * exist. BeOS returns EINVAL for some silly reason, however. */ if (other_pid != my_pid #ifndef WIN32 && other_pid != getppid() #endif ) { if (kill(other_pid, 0) == 0 || (errno != ESRCH && #ifdef __BEOS__ errno != EINVAL && #endif errno != EPERM)) { /* lockfile belongs to a live process */ ereport(FATAL, (errcode(ERRCODE_LOCK_FILE_EXISTS), errmsg("lock file \"%s\" already exists", filename), isDDLock ? (encoded_pid < 0 ? errhint("Is another postgres (PID %d) running in data directory \"%s\"?", (int) other_pid, refName) : errhint("Is another postmaster (PID %d) running in data directory \"%s\"?", (int) other_pid, refName)) : (encoded_pid < 0 ? errhint("Is another postgres (PID %d) using socket file \"%s\"?", (int) other_pid, refName) : errhint("Is another postmaster (PID %d) using socket file \"%s\"?", (int) other_pid, refName)))); } } /* * No, the creating process did not exist. However, it could be * that the postmaster crashed (or more likely was kill -9'd by a * clueless admin) but has left orphan backends behind. Check for * this by looking to see if there is an associated shmem segment * that is still in use. */ if (isDDLock) { char *ptr; unsigned long id1, id2; ptr = strchr(buffer, '\n'); if (ptr != NULL && (ptr = strchr(ptr + 1, '\n')) != NULL) { ptr++; if (sscanf(ptr, "%lu %lu", &id1, &id2) == 2) { if (PGSharedMemoryIsInUse(id1, id2)) ereport(FATAL, (errcode(ERRCODE_LOCK_FILE_EXISTS), errmsg("pre-existing shared memory block " "(key %lu, ID %lu) is still in use", id1, id2), errhint("If you're sure there are no old " "server processes still running, remove " "the shared memory block with " "the command \"ipcclean\", or just delete the file \"%s\".", filename))); } } } /* * Looks like nobody's home. Unlink the file and try again to * create it. Need a loop because of possible race condition * against other would-be creators. */ if (unlink(filename) < 0) ereport(FATAL, (errcode_for_file_access(), errmsg("could not remove old lock file \"%s\": %m", filename), errhint("The file seems accidentally left over, but " "it could not be removed. Please remove the file " "by hand and try again."))); } /* * Successfully created the file, now fill it. */ snprintf(buffer, sizeof(buffer), "%d\n%s\n", amPostmaster ? (int) my_pid : -((int) my_pid), DataDir); errno = 0; if (write(fd, buffer, strlen(buffer)) != strlen(buffer)) { int save_errno = errno; close(fd); unlink(filename); /* if write didn't set errno, assume problem is no disk space */ errno = save_errno ? save_errno : ENOSPC; ereport(FATAL, (errcode_for_file_access(), errmsg("could not write lock file \"%s\": %m", filename))); } if (close(fd)) { int save_errno = errno; unlink(filename); errno = save_errno; ereport(FATAL, (errcode_for_file_access(), errmsg("could not write lock file \"%s\": %m", filename))); } /* * Arrange for automatic removal of lockfile at proc_exit. */ on_proc_exit(UnlinkLockFile, PointerGetDatum(strdup(filename))); } void CreateDataDirLockFile(const char *datadir, bool amPostmaster) { char lockfile[MAXPGPATH]; snprintf(lockfile, sizeof(lockfile), "%s/postmaster.pid", datadir); CreateLockFile(lockfile, amPostmaster, true, datadir); /* Save name of lockfile for RecordSharedMemoryInLockFile */ strcpy(directoryLockFile, lockfile); } void CreateSocketLockFile(const char *socketfile, bool amPostmaster) { char lockfile[MAXPGPATH]; snprintf(lockfile, sizeof(lockfile), "%s.lock", socketfile); CreateLockFile(lockfile, amPostmaster, false, socketfile); /* Save name of lockfile for TouchSocketLockFile */ strcpy(socketLockFile, lockfile); } /* * TouchSocketLockFile -- mark socket lock file as recently accessed * * This routine should be called every so often to ensure that the lock file * has a recent mod or access date. That saves it * from being removed by overenthusiastic /tmp-directory-cleaner daemons. * (Another reason we should never have put the socket file in /tmp...) */ void TouchSocketLockFile(void) { /* Do nothing if we did not create a socket... */ if (socketLockFile[0] != '\0') { /* * utime() is POSIX standard, utimes() is a common alternative; if * we have neither, fall back to actually reading the file (which * only sets the access time not mod time, but that should be * enough in most cases). In all paths, we ignore errors. */ #ifdef HAVE_UTIME utime(socketLockFile, NULL); #else /* !HAVE_UTIME */ #ifdef HAVE_UTIMES utimes(socketLockFile, NULL); #else /* !HAVE_UTIMES */ int fd; char buffer[1]; fd = open(socketLockFile, O_RDONLY | PG_BINARY, 0); if (fd >= 0) { read(fd, buffer, sizeof(buffer)); close(fd); } #endif /* HAVE_UTIMES */ #endif /* HAVE_UTIME */ } } /* * Append information about a shared memory segment to the data directory * lock file (if we have created one). * * This may be called multiple times in the life of a postmaster, if we * delete and recreate shmem due to backend crash. Therefore, be prepared * to overwrite existing information. (As of 7.1, a postmaster only creates * one shm seg at a time; but for the purposes here, if we did have more than * one then any one of them would do anyway.) */ void RecordSharedMemoryInLockFile(unsigned long id1, unsigned long id2) { int fd; int len; char *ptr; char buffer[BLCKSZ]; /* * Do nothing if we did not create a lockfile (probably because we are * running standalone). */ if (directoryLockFile[0] == '\0') return; fd = open(directoryLockFile, O_RDWR | PG_BINARY, 0); if (fd < 0) { ereport(LOG, (errcode_for_file_access(), errmsg("could not open file \"%s\": %m", directoryLockFile))); return; } len = read(fd, buffer, sizeof(buffer) - 100); if (len < 0) { ereport(LOG, (errcode_for_file_access(), errmsg("could not read from file \"%s\": %m", directoryLockFile))); close(fd); return; } buffer[len] = '\0'; /* * Skip over first two lines (PID and path). */ ptr = strchr(buffer, '\n'); if (ptr == NULL || (ptr = strchr(ptr + 1, '\n')) == NULL) { elog(LOG, "bogus data in \"%s\"", directoryLockFile); close(fd); return; } ptr++; /* * Append key information. Format to try to keep it the same length * always (trailing junk won't hurt, but might confuse humans). */ sprintf(ptr, "%9lu %9lu\n", id1, id2); /* * And rewrite the data. Since we write in a single kernel call, this * update should appear atomic to onlookers. */ len = strlen(buffer); errno = 0; if (lseek(fd, (off_t) 0, SEEK_SET) != 0 || (int) write(fd, buffer, len) != len) { /* if write didn't set errno, assume problem is no disk space */ if (errno == 0) errno = ENOSPC; ereport(LOG, (errcode_for_file_access(), errmsg("could not write to file \"%s\": %m", directoryLockFile))); close(fd); return; } if (close(fd)) { ereport(LOG, (errcode_for_file_access(), errmsg("could not write to file \"%s\": %m", directoryLockFile))); } } /*------------------------------------------------------------------------- * Version checking support *------------------------------------------------------------------------- */ /* * Determine whether the PG_VERSION file in directory `path' indicates * a data version compatible with the version of this program. * * If compatible, return. Otherwise, ereport(FATAL). */ void ValidatePgVersion(const char *path) { char full_path[MAXPGPATH]; FILE *file; int ret; long file_major, file_minor; long my_major = 0, my_minor = 0; char *endptr; const char *version_string = PG_VERSION; my_major = strtol(version_string, &endptr, 10); if (*endptr == '.') my_minor = strtol(endptr + 1, NULL, 10); snprintf(full_path, sizeof(full_path), "%s/PG_VERSION", path); file = AllocateFile(full_path, "r"); if (!file) { if (errno == ENOENT) ereport(FATAL, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("\"%s\" is not a valid data directory", path), errdetail("File \"%s\" is missing.", full_path))); else ereport(FATAL, (errcode_for_file_access(), errmsg("could not open file \"%s\": %m", full_path))); } ret = fscanf(file, "%ld.%ld", &file_major, &file_minor); if (ret != 2) ereport(FATAL, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("\"%s\" is not a valid data directory", path), errdetail("File \"%s\" does not contain valid data.", full_path), errhint("You may need to initdb."))); FreeFile(file); if (my_major != file_major || my_minor != file_minor) ereport(FATAL, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("database files are incompatible with server"), errdetail("The data directory was initialized by PostgreSQL version %ld.%ld, " "which is not compatible with this version %s.", file_major, file_minor, version_string))); } /*------------------------------------------------------------------------- * Library preload support *------------------------------------------------------------------------- */ typedef void (*func_ptr) (); /* * process any libraries that should be preloaded and * optionally pre-initialized */ void process_preload_libraries(char *preload_libraries_string) { char *rawstring; List *elemlist; ListCell *l; if (preload_libraries_string == NULL) return; /* Need a modifiable copy of string */ rawstring = pstrdup(preload_libraries_string); /* Parse string into list of identifiers */ if (!SplitIdentifierString(rawstring, ',', &elemlist)) { /* syntax error in list */ pfree(rawstring); list_free(elemlist); ereport(LOG, (errcode(ERRCODE_SYNTAX_ERROR), errmsg("invalid list syntax for parameter \"preload_libraries\""))); return; } foreach(l, elemlist) { char *tok = (char *) lfirst(l); char *sep = strstr(tok, ":"); char *filename = NULL; char *funcname = NULL; func_ptr initfunc; if (sep) { /* * a colon separator implies there is an initialization * function that we need to run in addition to loading the * library */ size_t filename_len = sep - tok; size_t funcname_len = strlen(tok) - filename_len - 1; filename = (char *) palloc(filename_len + 1); memcpy(filename, tok, filename_len); filename[filename_len] = '\0'; funcname = (char *) palloc(funcname_len + 1); strcpy(funcname, sep + 1); } else { /* * no separator -- just load the library */ filename = pstrdup(tok); funcname = NULL; } canonicalize_path(filename); initfunc = (func_ptr) load_external_function(filename, funcname, true, NULL); if (initfunc) (*initfunc) (); if (funcname) ereport(LOG, (errmsg("preloaded library \"%s\" with initialization function \"%s\"", filename, funcname))); else ereport(LOG, (errmsg("preloaded library \"%s\"", filename))); pfree(filename); if (funcname) pfree(funcname); } pfree(rawstring); list_free(elemlist); }