]> granicus.if.org Git - postgresql/blobdiff - src/backend/utils/init/miscinit.c
Seems some C compilers think 'restrict' is a fully reserved word.
[postgresql] / src / backend / utils / init / miscinit.c
index 2b9ab066185fa70e1b2699687b65fac1157e4484..2d979afeada2f72952cf97d1d7d39b397c2fcf65 100644 (file)
@@ -3,12 +3,12 @@
  * miscinit.c
  *       miscellaneous initialization support stuff
  *
- * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *
  * IDENTIFICATION
- *       $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.116 2003/09/26 15:27:37 petere Exp $
+ *       $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.158 2006/08/16 04:32:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include <unistd.h>
 #include <grp.h>
 #include <pwd.h>
-#include <errno.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #ifdef HAVE_UTIME_H
 #include <utime.h>
 #endif
 
-#include "catalog/catname.h"
-#include "catalog/pg_shadow.h"
-#include "libpq/libpq-be.h"
+#include "catalog/pg_authid.h"
 #include "miscadmin.h"
+#include "postmaster/autovacuum.h"
+#include "storage/fd.h"
 #include "storage/ipc.h"
 #include "storage/pg_shmem.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
 #include "utils/builtins.h"
 #include "utils/guc.h"
-#include "utils/lsyscache.h"
 #include "utils/syscache.h"
 
 
+#define DIRECTORY_LOCK_FILE            "postmaster.pid"
+
 ProcessingMode Mode = InitProcessing;
 
-/* Note: we rely on these to initialize as zeroes */
-static char directoryLockFile[MAXPGPATH];
+/* Note: we rely on this to initialize as zeroes */
 static char socketLockFile[MAXPGPATH];
 
 
@@ -54,32 +55,12 @@ static char socketLockFile[MAXPGPATH];
  *
  * 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
+ * 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;
-}
+bool IgnoreSystemIndexes = false;
 
 /* ----------------------------------------------------------------
  *             system index reindexing support
@@ -115,19 +96,29 @@ ReindexIsProcessingIndex(Oid indexOid)
 /*
  * SetReindexProcessing
  *             Set flag that specified heap/index are being reindexed.
- *             Pass InvalidOid to indicate that reindexing is not active.
  */
 void
 SetReindexProcessing(Oid heapOid, Oid indexOid)
 {
-       /* Args should be both, or neither, InvalidOid */
-       Assert((heapOid == InvalidOid) == (indexOid == InvalidOid));
+       Assert(OidIsValid(heapOid) && OidIsValid(indexOid));
        /* Reindexing is not re-entrant. */
-       Assert(indexOid == InvalidOid || currentlyReindexedIndex == InvalidOid);
+       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
  * ----------------------------------------------------------------
@@ -157,12 +148,55 @@ void
 SetDataDir(const char *dir)
 {
        char       *new;
-       int                     newlen;
 
        AssertArg(dir);
 
        /* If presented path is relative, convert to absolute */
-       if (!is_absolute_path(dir))
+       new = make_absolute_path(dir);
+
+       if (DataDir)
+               free(DataDir);
+       DataDir = new;
+}
+
+/*
+ * Change working directory to DataDir.  Most of the postmaster and backend
+ * code assumes that we are in DataDir so it can use relative paths to access
+ * stuff in and under the data directory.  For convenience during path
+ * setup, however, we don't force the chdir to occur during SetDataDir.
+ */
+void
+ChangeToDataDir(void)
+{
+       AssertState(DataDir);
+
+       if (chdir(DataDir) < 0)
+               ereport(FATAL,
+                               (errcode_for_file_access(),
+                                errmsg("could not change directory to \"%s\": %m",
+                                               DataDir)));
+}
+
+/*
+ * 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: interpretation of relative-path arguments during postmaster startup
+ * should happen before doing ChangeToDataDir(), else the user will probably
+ * not like the results.
+ */
+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;
@@ -191,106 +225,144 @@ SetDataDir(const char *dir)
                        }
                }
 
-               new = malloc(strlen(buf) + 1 + strlen(dir) + 1);
+               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, dir);
+               sprintf(new, "%s/%s", buf, path);
                free(buf);
        }
        else
        {
-               new = strdup(dir);
+               new = strdup(path);
                if (!new)
                        ereport(FATAL,
                                        (errcode(ERRCODE_OUT_OF_MEMORY),
                                         errmsg("out of memory")));
        }
 
-       /*
-        * Strip any trailing slash.  Not strictly necessary, but avoids
-        * generating funny-looking paths to individual files.
-        */
-       newlen = strlen(new);
-       if (newlen > 1 && new[newlen - 1] == '/'
-#ifdef WIN32
-               || new[newlen - 1] == '\\'
-#endif
-               )
-               new[newlen - 1] = '\0';
+       /* Make sure punctuation is canonical, too */
+       canonicalize_path(new);
 
-       if (DataDir)
-               free(DataDir);
-       DataDir = new;
+       return new;
 }
 
 
 /* ----------------------------------------------------------------
- *     User ID things
+ *     User ID state
+ *
+ * We have to track several different values associated with the concept
+ * of "user ID".
+ *
+ * AuthenticatedUserId is determined at connection start and never changes.
+ *
+ * SessionUserId is initially the same as AuthenticatedUserId, but can be
+ * changed by SET SESSION AUTHORIZATION (if AuthenticatedUserIsSuperuser).
+ * This is the ID reported by the SESSION_USER SQL function.
  *
- * 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.
+ * OuterUserId is the current user ID in effect at the "outer level" (outside
+ * any transaction or function).  This is initially the same as SessionUserId,
+ * but can be changed by SET ROLE to any role that SessionUserId is a
+ * member of.  We store this mainly so that AtAbort_UserId knows what to
+ * reset CurrentUserId to.
+ *
+ * CurrentUserId is the current effective user ID; this is the one to use
+ * for all normal permissions-checking purposes.  At outer level this will
+ * be the same as OuterUserId, but it changes during calls to SECURITY
+ * DEFINER functions, as well as locally in some specialized commands.
  * ----------------------------------------------------------------
  */
-static AclId AuthenticatedUserId = 0;
-static AclId SessionUserId = 0;
-static AclId CurrentUserId = 0;
+static Oid     AuthenticatedUserId = InvalidOid;
+static Oid     SessionUserId = InvalidOid;
+static Oid     OuterUserId = InvalidOid;
+static Oid     CurrentUserId = InvalidOid;
 
+/* We also have to remember the superuser state of some of these levels */
 static bool AuthenticatedUserIsSuperuser = false;
+static bool SessionUserIsSuperuser = false;
+
+/* We also remember if a SET ROLE is currently active */
+static bool SetRoleIsActive = false;
+
 
 /*
- * This function is relevant for all privilege checks.
+ * GetUserId/SetUserId - get/set the current effective user ID.
  */
-AclId
+Oid
 GetUserId(void)
 {
-       AssertState(AclIdIsValid(CurrentUserId));
+       AssertState(OidIsValid(CurrentUserId));
        return CurrentUserId;
 }
 
 
 void
-SetUserId(AclId newid)
+SetUserId(Oid userid)
 {
-       AssertArg(AclIdIsValid(newid));
-       CurrentUserId = newid;
+       AssertArg(OidIsValid(userid));
+       CurrentUserId = userid;
 }
 
 
 /*
- * This value is only relevant for informational purposes.
+ * GetOuterUserId/SetOuterUserId - get/set the outer-level user ID.
  */
-AclId
+Oid
+GetOuterUserId(void)
+{
+       AssertState(OidIsValid(OuterUserId));
+       return OuterUserId;
+}
+
+
+static void
+SetOuterUserId(Oid userid)
+{
+       AssertArg(OidIsValid(userid));
+       OuterUserId = userid;
+
+       /* We force the effective user ID to match, too */
+       CurrentUserId = userid;
+}
+
+
+/*
+ * GetSessionUserId/SetSessionUserId - get/set the session user ID.
+ */
+Oid
 GetSessionUserId(void)
 {
-       AssertState(AclIdIsValid(SessionUserId));
+       AssertState(OidIsValid(SessionUserId));
        return SessionUserId;
 }
 
 
-void
-SetSessionUserId(AclId newid)
+static void
+SetSessionUserId(Oid userid, bool is_superuser)
 {
-       AssertArg(AclIdIsValid(newid));
-       SessionUserId = newid;
-       /* Current user defaults to session user. */
-       if (!AclIdIsValid(CurrentUserId))
-               CurrentUserId = newid;
+       AssertArg(OidIsValid(userid));
+       SessionUserId = userid;
+       SessionUserIsSuperuser = is_superuser;
+       SetRoleIsActive = false;
+
+       /* We force the effective user IDs to match, too */
+       OuterUserId = userid;
+       CurrentUserId = userid;
 }
 
 
+/*
+ * Initialize user identity during normal backend startup
+ */
 void
-InitializeSessionUserId(const char *username)
+InitializeSessionUserId(const char *rolename)
 {
-       HeapTuple       userTup;
+       HeapTuple       roleTup;
+       Form_pg_authid rform;
        Datum           datum;
        bool            isnull;
-       AclId           usesysid;
+       Oid                     roleid;
 
        /*
         * Don't do scans if we're bootstrapping, none of the system catalogs
@@ -301,35 +373,77 @@ InitializeSessionUserId(const char *username)
        /* call only once */
        AssertState(!OidIsValid(AuthenticatedUserId));
 
-       userTup = SearchSysCache(SHADOWNAME,
-                                                        PointerGetDatum(username),
+       roleTup = SearchSysCache(AUTHNAME,
+                                                        PointerGetDatum(rolename),
                                                         0, 0, 0);
-       if (!HeapTupleIsValid(userTup))
+       if (!HeapTupleIsValid(roleTup))
                ereport(FATAL,
-                               (errcode(ERRCODE_UNDEFINED_OBJECT),
-                                errmsg("user \"%s\" does not exist", username)));
+                               (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
+                                errmsg("role \"%s\" does not exist", rolename)));
+
+       rform = (Form_pg_authid) GETSTRUCT(roleTup);
+       roleid = HeapTupleGetOid(roleTup);
+
+       AuthenticatedUserId = roleid;
+       AuthenticatedUserIsSuperuser = rform->rolsuper;
+
+       /* This sets OuterUserId/CurrentUserId too */
+       SetSessionUserId(roleid, AuthenticatedUserIsSuperuser);
 
-       usesysid = ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid;
+       /* Also mark our PGPROC entry with the authenticated user id */
+       /* (We assume this is an atomic store so no lock is needed) */
+       MyProc->roleId = roleid;
 
-       AuthenticatedUserId = usesysid;
-       AuthenticatedUserIsSuperuser = ((Form_pg_shadow) GETSTRUCT(userTup))->usesuper;
+       /*
+        * These next checks are not enforced when in standalone mode, so that
+        * there is a way to recover from sillinesses like "UPDATE pg_authid SET
+        * rolcanlogin = false;".
+        *
+        * We do not enforce them for the autovacuum process either.
+        */
+       if (IsUnderPostmaster && !IsAutoVacuumProcess())
+       {
+               /*
+                * Is role allowed to login at all?
+                */
+               if (!rform->rolcanlogin)
+                       ereport(FATAL,
+                                       (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
+                                        errmsg("role \"%s\" is not permitted to log in",
+                                                       rolename)));
 
-       SetSessionUserId(usesysid); /* sets CurrentUserId too */
+               /*
+                * Check connection limit for this role.
+                *
+                * There is a race condition here --- we create our PGPROC before
+                * checking for other PGPROCs.  If two backends did this at about the
+                * same time, they might both think they were over the limit, while
+                * ideally one should succeed and one fail.  Getting that to work
+                * exactly seems more trouble than it is worth, however; instead we
+                * just document that the connection limit is approximate.
+                */
+               if (rform->rolconnlimit >= 0 &&
+                       !AuthenticatedUserIsSuperuser &&
+                       CountUserBackends(roleid) > rform->rolconnlimit)
+                       ereport(FATAL,
+                                       (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
+                                        errmsg("too many connections for role \"%s\"",
+                                                       rolename)));
+       }
 
        /* Record username and superuser status as GUC settings too */
-       SetConfigOption("session_authorization", username,
+       SetConfigOption("session_authorization", rolename,
                                        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.
+        * Set up user-specific configuration variables.  This is a good place to
+        * do it so we don't have to read pg_authid twice during session startup.
         */
-       datum = SysCacheGetAttr(SHADOWNAME, userTup,
-                                                       Anum_pg_shadow_useconfig, &isnull);
+       datum = SysCacheGetAttr(AUTHNAME, roleTup,
+                                                       Anum_pg_authid_rolconfig, &isnull);
        if (!isnull)
        {
                ArrayType  *a = DatumGetArrayTypeP(datum);
@@ -337,23 +451,41 @@ InitializeSessionUserId(const char *username)
                ProcessGUCArray(a, PGC_S_USER);
        }
 
-       ReleaseSysCache(userTup);
+       ReleaseSysCache(roleTup);
 }
 
 
+/*
+ * Initialize user identity during special backend startup
+ */
 void
 InitializeSessionUserIdStandalone(void)
 {
        /* This function should only be called in a single-user backend. */
-       AssertState(!IsUnderPostmaster);
+       AssertState(!IsUnderPostmaster || IsAutoVacuumProcess());
 
        /* call only once */
        AssertState(!OidIsValid(AuthenticatedUserId));
 
-       AuthenticatedUserId = BOOTSTRAP_USESYSID;
+       AuthenticatedUserId = BOOTSTRAP_SUPERUSERID;
        AuthenticatedUserIsSuperuser = true;
 
-       SetSessionUserId(BOOTSTRAP_USESYSID);
+       SetSessionUserId(BOOTSTRAP_SUPERUSERID, true);
+}
+
+
+/*
+ * Reset effective userid during AbortTransaction
+ *
+ * This is essentially SetUserId(GetOuterUserId()), but without the Asserts.
+ * The reason is that if a backend's InitPostgres transaction fails (eg,
+ * because an invalid user name was given), we have to be able to get through
+ * AbortTransaction without asserting.
+ */
+void
+AtAbort_UserId(void)
+{
+       CurrentUserId = OuterUserId;
 }
 
 
@@ -364,21 +496,82 @@ InitializeSessionUserIdStandalone(void)
  * 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.
+ *
+ * Note: this is not an especially clean place to do the permission check.
+ * It's OK because the check does not require catalog access and can't
+ * fail during an end-of-transaction GUC reversion, but we may someday
+ * have to push it up into assign_session_authorization.
  */
 void
-SetSessionAuthorization(AclId userid, bool is_superuser)
+SetSessionAuthorization(Oid userid, bool is_superuser)
 {
        /* Must have authenticated already, else can't make permission check */
-       AssertState(AclIdIsValid(AuthenticatedUserId));
+       AssertState(OidIsValid(AuthenticatedUserId));
 
        if (userid != AuthenticatedUserId &&
                !AuthenticatedUserIsSuperuser)
                ereport(ERROR,
                                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-                         errmsg("permission denied to set session authorization")));
+                                errmsg("permission denied to set session authorization")));
+
+       SetSessionUserId(userid, is_superuser);
+
+       SetConfigOption("is_superuser",
+                                       is_superuser ? "on" : "off",
+                                       PGC_INTERNAL, PGC_S_OVERRIDE);
+}
+
+/*
+ * Report current role id
+ *             This follows the semantics of SET ROLE, ie return the outer-level ID
+ *             not the current effective ID, and return InvalidOid when the setting
+ *             is logically SET ROLE NONE.
+ */
+Oid
+GetCurrentRoleId(void)
+{
+       if (SetRoleIsActive)
+               return OuterUserId;
+       else
+               return InvalidOid;
+}
+
+/*
+ * Change Role ID while running (SET ROLE)
+ *
+ * If roleid is InvalidOid, we are doing SET ROLE NONE: revert to the
+ * session user authorization. In this case the is_superuser argument
+ * is ignored.
+ *
+ * When roleid is not InvalidOid, the caller must have checked whether
+ * the session user has permission to become that role.  (We cannot check
+ * here because this routine must be able to execute in a failed transaction
+ * to restore a prior value of the ROLE GUC variable.)
+ */
+void
+SetCurrentRoleId(Oid roleid, bool is_superuser)
+{
+       /*
+        * Get correct info if it's SET ROLE NONE
+        *
+        * If SessionUserId hasn't been set yet, just do nothing --- the eventual
+        * SetSessionUserId call will fix everything.  This is needed since we
+        * will get called during GUC initialization.
+        */
+       if (!OidIsValid(roleid))
+       {
+               if (!OidIsValid(SessionUserId))
+                       return;
+
+               roleid = SessionUserId;
+               is_superuser = SessionUserIsSuperuser;
 
-       SetSessionUserId(userid);
-       SetUserId(userid);
+               SetRoleIsActive = false;
+       }
+       else
+               SetRoleIsActive = true;
+
+       SetOuterUserId(roleid);
 
        SetConfigOption("is_superuser",
                                        is_superuser ? "on" : "off",
@@ -387,30 +580,29 @@ SetSessionAuthorization(AclId userid, bool is_superuser)
 
 
 /*
- * Get user name from user id
+ * Get user name from user oid
  */
 char *
-GetUserNameFromId(AclId userid)
+GetUserNameFromId(Oid roleid)
 {
        HeapTuple       tuple;
        char       *result;
 
-       tuple = SearchSysCache(SHADOWSYSID,
-                                                  ObjectIdGetDatum(userid),
+       tuple = SearchSysCache(AUTHOID,
+                                                  ObjectIdGetDatum(roleid),
                                                   0, 0, 0);
        if (!HeapTupleIsValid(tuple))
                ereport(ERROR,
                                (errcode(ERRCODE_UNDEFINED_OBJECT),
-                                errmsg("invalid user ID: %d", userid)));
+                                errmsg("invalid role OID: %u", roleid)));
 
-       result = pstrdup(NameStr(((Form_pg_shadow) GETSTRUCT(tuple))->usename));
+       result = pstrdup(NameStr(((Form_pg_authid) GETSTRUCT(tuple))->rolname));
 
        ReleaseSysCache(tuple);
        return result;
 }
 
 
-
 /*-------------------------------------------------------------------------
  *                             Interlock-file support
  *
@@ -472,14 +664,17 @@ CreateLockFile(const char *filename, bool amPostmaster,
        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.
+        * 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)
@@ -508,7 +703,7 @@ CreateLockFile(const char *filename, bool amPostmaster,
                                         errmsg("could not open lock file \"%s\": %m",
                                                        filename)));
                }
-               if ((len = read(fd, buffer, sizeof(buffer) - 1)) <= 0)
+               if ((len = read(fd, buffer, sizeof(buffer) - 1)) < 0)
                        ereport(FATAL,
                                        (errcode_for_file_access(),
                                         errmsg("could not read lock file \"%s\": %m",
@@ -522,22 +717,54 @@ CreateLockFile(const char *filename, bool amPostmaster,
                other_pid = (pid_t) (encoded_pid < 0 ? -encoded_pid : encoded_pid);
 
                if (other_pid <= 0)
-                       elog(FATAL, "bogus data in lock file \"%s\"", filename);
+                       elog(FATAL, "bogus data in lock file \"%s\": \"%s\"",
+                                filename, buffer);
 
                /*
                 * 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.
+                * exist.
                 */
-               if (other_pid != my_pid)
+               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 != ESRCH && errno != EPERM))
                        {
                                /* lockfile belongs to a live process */
                                ereport(FATAL,
@@ -545,21 +772,25 @@ CreateLockFile(const char *filename, bool amPostmaster,
                                                 errmsg("lock file \"%s\" already exists",
                                                                filename),
                                                 isDDLock ?
-                                        errhint("Is another %s (PID %d) running in data directory \"%s\"?",
-                                                  (encoded_pid < 0 ? "postgres" : "postmaster"),
-                                                        (int) other_pid, refName) :
-                                                errhint("Is another %s (PID %d) using socket file \"%s\"?",
-                                                  (encoded_pid < 0 ? "postgres" : "postmaster"),
-                                                                (int) other_pid, refName)));
+                                                (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.
+                * 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)
                {
@@ -577,22 +808,23 @@ CreateLockFile(const char *filename, bool amPostmaster,
                                        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 \"ipcrm\", or just delete the file \"%s\".",
-                                                                          filename)));
+                                                                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\", \"ipcrm\", "
+                                                                                "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.
+                * 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,
@@ -600,7 +832,7 @@ CreateLockFile(const char *filename, bool amPostmaster,
                                         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 "
+                                                  "it could not be removed. Please remove the file "
                                                         "by hand and try again.")));
        }
 
@@ -621,9 +853,18 @@ CreateLockFile(const char *filename, bool amPostmaster,
                errno = save_errno ? save_errno : ENOSPC;
                ereport(FATAL,
                                (errcode_for_file_access(),
-                         errmsg("could not write lock file \"%s\": %m", filename)));
+                                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)));
        }
-       close(fd);
 
        /*
         * Arrange for automatic removal of lockfile at proc_exit.
@@ -631,17 +872,22 @@ CreateLockFile(const char *filename, bool amPostmaster,
        on_proc_exit(UnlinkLockFile, PointerGetDatum(strdup(filename)));
 }
 
+/*
+ * Create the data directory lockfile.
+ *
+ * When this is called, we must have already switched the working
+ * directory to DataDir, so we can just use a relative path.  This
+ * helps ensure that we are locking the directory we should be.
+ */
 void
-CreateDataDirLockFile(const char *datadir, bool amPostmaster)
+CreateDataDirLockFile(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);
+       CreateLockFile(DIRECTORY_LOCK_FILE, amPostmaster, true, DataDir);
 }
 
+/*
+ * Create a lockfile for the specified Unix socket file.
+ */
 void
 CreateSocketLockFile(const char *socketfile, bool amPostmaster)
 {
@@ -668,10 +914,10 @@ TouchSocketLockFile(void)
        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.
+                * 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);
@@ -695,7 +941,7 @@ TouchSocketLockFile(void)
 
 /*
  * Append information about a shared memory segment to the data directory
- * lock file (if we have created one).
+ * lock file.
  *
  * 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
@@ -711,29 +957,22 @@ RecordSharedMemoryInLockFile(unsigned long id1, unsigned long id2)
        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);
+       fd = open(DIRECTORY_LOCK_FILE, O_RDWR | PG_BINARY, 0);
        if (fd < 0)
        {
                ereport(LOG,
                                (errcode_for_file_access(),
                                 errmsg("could not open file \"%s\": %m",
-                                               directoryLockFile)));
+                                               DIRECTORY_LOCK_FILE)));
                return;
        }
        len = read(fd, buffer, sizeof(buffer) - 100);
-       if (len <= 0)
+       if (len < 0)
        {
                ereport(LOG,
                                (errcode_for_file_access(),
                                 errmsg("could not read from file \"%s\": %m",
-                                               directoryLockFile)));
+                                               DIRECTORY_LOCK_FILE)));
                close(fd);
                return;
        }
@@ -746,7 +985,7 @@ RecordSharedMemoryInLockFile(unsigned long id1, unsigned long id2)
        if (ptr == NULL ||
                (ptr = strchr(ptr + 1, '\n')) == NULL)
        {
-               elog(LOG, "bogus data in \"%s\"", directoryLockFile);
+               elog(LOG, "bogus data in \"%s\"", DIRECTORY_LOCK_FILE);
                close(fd);
                return;
        }
@@ -773,11 +1012,17 @@ RecordSharedMemoryInLockFile(unsigned long id1, unsigned long id2)
                ereport(LOG,
                                (errcode_for_file_access(),
                                 errmsg("could not write to file \"%s\": %m",
-                                               directoryLockFile)));
+                                               DIRECTORY_LOCK_FILE)));
                close(fd);
                return;
        }
-       close(fd);
+       if (close(fd))
+       {
+               ereport(LOG,
+                               (errcode_for_file_access(),
+                                errmsg("could not write to file \"%s\": %m",
+                                               DIRECTORY_LOCK_FILE)));
+       }
 }
 
 
@@ -843,7 +1088,7 @@ ValidatePgVersion(const char *path)
                                (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.",
+                                                  "which is not compatible with this version %s.",
                                                   file_major, file_minor, version_string)));
 }
 
@@ -852,95 +1097,91 @@ ValidatePgVersion(const char *path)
  *-------------------------------------------------------------------------
  */
 
-#if defined(__mc68000__) && defined(__ELF__)
-typedef int32 ((*func_ptr) ());
-
-#else
-typedef char *((*func_ptr) ());
-#endif
+/* 
+ * GUC variables: lists of library names to be preloaded at postmaster
+ * start and at backend start
+ */
+char      *shared_preload_libraries_string = NULL;
+char      *local_preload_libraries_string = NULL;
 
 /*
- * process any libraries that should be preloaded and
- * optionally pre-initialized
+ * load the shared libraries listed in 'libraries'
+ *
+ * 'gucname': name of GUC variable, for error reports
+ * 'restricted': if true, force libraries to be in $libdir/plugins/
  */
-void
-process_preload_libraries(char *preload_libraries_string)
+static void
+load_libraries(const char *libraries, const char *gucname, bool restricted)
 {
        char       *rawstring;
        List       *elemlist;
-       List       *l;
+       ListCell   *l;
 
-       if (preload_libraries_string == NULL)
-               return;
+       if (libraries == NULL || libraries[0] == '\0')
+               return;                                 /* nothing to do */
 
        /* Need a modifiable copy of string */
-       rawstring = pstrdup(preload_libraries_string);
+       rawstring = pstrdup(libraries);
 
        /* Parse string into list of identifiers */
        if (!SplitIdentifierString(rawstring, ',', &elemlist))
        {
                /* syntax error in list */
                pfree(rawstring);
-               freeList(elemlist);
+               list_free(elemlist);
                ereport(LOG,
                                (errcode(ERRCODE_SYNTAX_ERROR),
-                                errmsg("invalid list syntax for parameter \"preload_libraries\"")));
+                                errmsg("invalid list syntax in parameter \"%s\"",
+                                               gucname)));
                return;
        }
 
        foreach(l, elemlist)
        {
                char       *tok = (char *) lfirst(l);
-               char       *sep = strstr(tok, ":");
-               char       *filename = NULL;
-               char       *funcname = NULL;
-               func_ptr        initfunc;
+               char       *filename;
 
-               if (sep)
+               filename = pstrdup(tok);
+               canonicalize_path(filename);
+               /* If restricting, insert $libdir/plugins if not mentioned already */
+               if (restricted && first_dir_separator(filename) == NULL)
                {
-                       /*
-                        * 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;
-               }
-
-               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)));
+                       char   *expanded;
 
+                       expanded = palloc(strlen("$libdir/plugins/") + strlen(filename) + 1);
+                       strcpy(expanded, "$libdir/plugins/");
+                       strcat(expanded, filename);
+                       pfree(filename);
+                       filename = expanded;
+               }
+               load_file(filename, restricted);
+               ereport(LOG,
+                               (errmsg("loaded library \"%s\"", filename)));
                pfree(filename);
-               if (funcname)
-                       pfree(funcname);
        }
 
        pfree(rawstring);
-       freeList(elemlist);
+       list_free(elemlist);
+}
+
+/*
+ * process any libraries that should be preloaded at postmaster start
+ */
+void
+process_shared_preload_libraries(void)
+{
+       load_libraries(shared_preload_libraries_string,
+                                  "shared_preload_libraries",
+                                  false);
+}
+
+/*
+ * process any libraries that should be preloaded at backend start
+ */
+void
+process_local_preload_libraries(void)
+{
+       load_libraries(local_preload_libraries_string,
+                                  "local_preload_libraries",
+                                  true);
 }