mirror of
https://github.com/postgres/postgres.git
synced 2025-06-13 07:41:39 +03:00
Get rid of not-very-portable fcntl(F_SETLK) mechanism for locking the Unix
socket file, in favor of having an ordinary lockfile beside the socket file. Clean up a few robustness problems in the lockfile code. If postmaster is going to reject a connection request based on database state, it will now tell you so before authentication exchange not after. (Of course, a failure after is still possible if conditions change meanwhile, but this makes life easier for a yet-to-be-written pg_ping utility.)
This commit is contained in:
Tom Lane
@ -1,14 +1,14 @@
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/*-------------------------------------------------------------------------
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*
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* miscinit.c
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* miscellanious initialization support stuff
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* miscellaneous initialization support stuff
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*
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* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.58 2000/11/17 01:24:46 tgl Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.59 2000/11/29 20:59:53 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -32,8 +32,6 @@
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#include "utils/builtins.h"
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#include "utils/syscache.h"
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static char *GetPidFname(void);
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#ifdef CYR_RECODE
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unsigned char RecodeForwTable[128];
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@ -43,6 +41,7 @@ unsigned char RecodeBackTable[128];
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ProcessingMode Mode = InitProcessing;
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/* ----------------------------------------------------------------
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* ignoring system indexes support stuff
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* ----------------------------------------------------------------
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@ -99,10 +98,70 @@ SetDatabaseName(const char *name)
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}
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}
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#ifndef MULTIBYTE
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/* even if MULTIBYTE is not enabled, these functions are necessary
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* since pg_proc.h has references to them.
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/*
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* Set data directory, but make sure it's an absolute path. Use this,
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* never set DataDir directly.
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*/
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void
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SetDataDir(const char *dir)
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{
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char *new;
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AssertArg(dir);
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if (DataDir)
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free(DataDir);
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if (dir[0] != '/')
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{
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char *buf;
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size_t buflen;
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buflen = MAXPGPATH;
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for (;;)
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{
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buf = malloc(buflen);
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if (!buf)
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elog(FATAL, "out of memory");
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if (getcwd(buf, buflen))
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break;
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else if (errno == ERANGE)
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{
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free(buf);
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buflen *= 2;
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continue;
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}
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else
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{
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free(buf);
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elog(FATAL, "cannot get current working directory: %m");
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}
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}
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new = malloc(strlen(buf) + 1 + strlen(dir) + 1);
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sprintf(new, "%s/%s", buf, dir);
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free(buf);
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}
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else
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{
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new = strdup(dir);
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}
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if (!new)
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elog(FATAL, "out of memory");
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DataDir = new;
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}
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/* ----------------------------------------------------------------
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* MULTIBYTE stub code
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*
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* Even if MULTIBYTE is not enabled, these functions are necessary
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* since pg_proc.h has references to them.
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* ----------------------------------------------------------------
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*/
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#ifndef MULTIBYTE
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Datum
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getdatabaseencoding(PG_FUNCTION_ARGS)
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@ -124,7 +183,13 @@ PG_char_to_encoding(PG_FUNCTION_ARGS)
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#endif
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/* ----------------------------------------------------------------
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* CYR_RECODE support
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* ----------------------------------------------------------------
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*/
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#ifdef CYR_RECODE
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#define MAX_TOKEN 80
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/* Some standard C libraries, including GNU, have an isblank() function.
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@ -376,228 +441,189 @@ GetUserName(Oid userid)
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/*-------------------------------------------------------------------------
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* Set data directory, but make sure it's an absolute path. Use this,
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* never set DataDir directly.
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*-------------------------------------------------------------------------
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*/
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void
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SetDataDir(const char *dir)
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{
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char *new;
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AssertArg(dir);
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if (DataDir)
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free(DataDir);
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if (dir[0] != '/')
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{
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char *buf;
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size_t buflen;
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buflen = MAXPGPATH;
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for (;;)
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{
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buf = malloc(buflen);
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if (!buf)
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elog(FATAL, "out of memory");
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if (getcwd(buf, buflen))
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break;
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else if (errno == ERANGE)
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{
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free(buf);
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buflen *= 2;
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continue;
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}
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else
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{
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free(buf);
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elog(FATAL, "cannot get current working directory: %m");
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}
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}
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new = malloc(strlen(buf) + 1 + strlen(dir) + 1);
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sprintf(new, "%s/%s", buf, dir);
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}
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else
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{
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new = strdup(dir);
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}
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if (!new)
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elog(FATAL, "out of memory");
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DataDir = new;
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}
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/*-------------------------------------------------------------------------
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* Interlock-file support
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*
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* postmaster pid file stuffs. $DATADIR/postmaster.pid is created when:
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* These routines are used to create both a data-directory lockfile
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* ($DATADIR/postmaster.pid) and a Unix-socket-file lockfile ($SOCKFILE.lock).
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* Both kinds of files contain the same info:
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*
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* (1) postmaster starts. In this case pid > 0.
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* (2) postgres starts in standalone mode. In this case
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* pid < 0
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* Owning process' PID
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* Data directory path
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*
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* to gain an interlock.
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*
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* SetPidFname(datadir)
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* Remember the the pid file name. This is neccesary
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* UnlinkPidFile() is called from proc_exit().
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*
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* GetPidFname(datadir)
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* Get the pid file name. SetPidFname() should be called
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* before GetPidFname() gets called.
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*
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* UnlinkPidFile()
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* This is called from proc_exit() and unlink the pid file.
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*
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* SetPidFile(pid_t pid)
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* Create the pid file. On failure, it checks if the process
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* actually exists or not. SetPidFname() should be called
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* in prior to calling SetPidFile().
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* By convention, the owning process' PID is negated if it is a standalone
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* backend rather than a postmaster. This is just for informational purposes.
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* The path is also just for informational purposes (so that a socket lockfile
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* can be more easily traced to the associated postmaster).
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*
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* On successful lockfile creation, a proc_exit callback to remove the
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* lockfile is automatically created.
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*-------------------------------------------------------------------------
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*/
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/*
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* Path to pid file. proc_exit() remember it to unlink the file.
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* proc_exit callback to remove a lockfile.
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*/
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static char PidFile[MAXPGPATH];
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/*
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* Remove the pid file. This function is called from proc_exit.
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*/
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void
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UnlinkPidFile(void)
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static void
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UnlinkLockFile(int status, Datum filename)
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{
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unlink(PidFile);
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unlink((char *) DatumGetPointer(filename));
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/* Should we complain if the unlink fails? */
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}
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/*
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* Set path to the pid file
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* Create a lockfile, if possible
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*
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* Call CreateLockFile with the name of the lockfile to be created. If
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* successful, it returns zero. On detecting a collision, it returns
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* the PID or negated PID of the lockfile owner --- the caller is responsible
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* for producing an appropriate error message.
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*/
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void
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SetPidFname(char *datadir)
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{
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snprintf(PidFile, sizeof(PidFile), "%s/%s", datadir, PIDFNAME);
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}
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/*
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* Get path to the pid file
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*/
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static char *
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GetPidFname(void)
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{
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return (PidFile);
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}
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/*
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* Create the pid file
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*/
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int
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SetPidFile(pid_t pid)
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static int
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CreateLockFile(const char *filename, bool amPostmaster)
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{
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int fd;
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char *pidfile;
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char pidstr[32];
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char buffer[MAXPGPATH + 32];
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int len;
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pid_t post_pid;
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int is_postgres = 0;
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int encoded_pid;
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pid_t other_pid;
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pid_t my_pid = getpid();
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/*
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* Creating pid file
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* We need a loop here because of race conditions.
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*/
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pidfile = GetPidFname();
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fd = open(pidfile, O_RDWR | O_CREAT | O_EXCL, 0600);
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if (fd < 0)
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for (;;)
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{
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/*
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* Try to create the lock file --- O_EXCL makes this atomic.
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*/
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fd = open(filename, O_RDWR | O_CREAT | O_EXCL, 0600);
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if (fd >= 0)
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break; /* Success; exit the retry loop */
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/*
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* Couldn't create the pid file. Probably it already exists.
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*/
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if (errno != EEXIST && errno != EACCES)
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elog(FATAL, "Can't create lock file %s: %m", filename);
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/*
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* Couldn't create the pid file. Probably it already exists. Read
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* the file to see if the process actually exists
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* Read the file to get the old owner's PID. Note race condition
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* here: file might have been deleted since we tried to create it.
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*/
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fd = open(pidfile, O_RDONLY, 0600);
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fd = open(filename, O_RDONLY, 0600);
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if (fd < 0)
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{
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fprintf(stderr, "Can't open pid file: %s\n", pidfile);
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fprintf(stderr, "Please check the permission and try again.\n");
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return (-1);
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}
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if ((len = read(fd, pidstr, sizeof(pidstr) - 1)) < 0)
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{
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fprintf(stderr, "Can't read pid file: %s\n", pidfile);
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fprintf(stderr, "Please check the permission and try again.\n");
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close(fd);
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return (-1);
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if (errno == ENOENT)
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continue; /* race condition; try again */
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elog(FATAL, "Can't read lock file %s: %m", filename);
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}
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if ((len = read(fd, buffer, sizeof(buffer) - 1)) <= 0)
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elog(FATAL, "Can't read lock file %s: %m", filename);
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close(fd);
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buffer[len] = '\0';
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encoded_pid = atoi(buffer);
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/* if pid < 0, the pid is for postgres, not postmaster */
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other_pid = (pid_t) (encoded_pid < 0 ? -encoded_pid : encoded_pid);
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if (other_pid <= 0)
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elog(FATAL, "Bogus data in lock file %s", filename);
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/*
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* Check to see if the process actually exists
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* Check to see if the other process still exists
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*/
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pidstr[len] = '\0';
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post_pid = (pid_t) atoi(pidstr);
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/* if pid < 0, the pid is for postgres, not postmatser */
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if (post_pid < 0)
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if (other_pid != my_pid)
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{
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is_postgres++;
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post_pid = -post_pid;
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if (kill(other_pid, 0) == 0 ||
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errno != ESRCH)
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return encoded_pid; /* lockfile belongs to a live process */
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}
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||||
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if (post_pid == 0 || (post_pid > 0 && kill(post_pid, 0) < 0))
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||||
{
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||||
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/*
|
||||
* No, the process did not exist. Unlink the file and try to
|
||||
* create it
|
||||
*/
|
||||
if (unlink(pidfile) < 0)
|
||||
{
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||||
fprintf(stderr, "Can't remove pid file: %s\n", pidfile);
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||||
fprintf(stderr, "The file seems accidently left, but I couldn't remove it.\n");
|
||||
fprintf(stderr, "Please remove the file by hand and try again.\n");
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||||
return (-1);
|
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}
|
||||
fd = open(pidfile, O_RDWR | O_CREAT | O_EXCL, 0600);
|
||||
if (fd < 0)
|
||||
{
|
||||
fprintf(stderr, "Can't create pid file: %s\n", pidfile);
|
||||
fprintf(stderr, "Please check the permission and try again.\n");
|
||||
return (-1);
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
|
||||
/*
|
||||
* Another postmaster is running
|
||||
*/
|
||||
fprintf(stderr, "Can't create pid file: %s\n", pidfile);
|
||||
if (is_postgres)
|
||||
fprintf(stderr, "Is another postgres (pid: %d) running?\n", (int) post_pid);
|
||||
else
|
||||
fprintf(stderr, "Is another postmaster (pid: %s) running?\n", pidstr);
|
||||
return (-1);
|
||||
}
|
||||
/*
|
||||
* No, the process did not exist. 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)
|
||||
elog(FATAL, "Can't remove old lock file %s: %m"
|
||||
"\n\tThe file seems accidentally left, but I couldn't remove it."
|
||||
"\n\tPlease remove the file by hand and try again.",
|
||||
filename);
|
||||
}
|
||||
|
||||
sprintf(pidstr, "%d", (int) pid);
|
||||
if (write(fd, pidstr, strlen(pidstr)) != strlen(pidstr))
|
||||
/*
|
||||
* Successfully created the file, now fill it.
|
||||
*/
|
||||
snprintf(buffer, sizeof(buffer), "%d\n%s\n",
|
||||
amPostmaster ? (int) my_pid : - ((int) my_pid),
|
||||
DataDir);
|
||||
if (write(fd, buffer, strlen(buffer)) != strlen(buffer))
|
||||
{
|
||||
fprintf(stderr, "Write to pid file failed\n");
|
||||
fprintf(stderr, "Please check the permission and try again.\n");
|
||||
int save_errno = errno;
|
||||
|
||||
close(fd);
|
||||
unlink(pidfile);
|
||||
return (-1);
|
||||
unlink(filename);
|
||||
errno = save_errno;
|
||||
elog(FATAL, "Can't write lock file %s: %m", filename);
|
||||
}
|
||||
close(fd);
|
||||
|
||||
return (0);
|
||||
/*
|
||||
* Arrange for automatic removal of lockfile at proc_exit.
|
||||
*/
|
||||
on_proc_exit(UnlinkLockFile, PointerGetDatum(strdup(filename)));
|
||||
|
||||
return 0; /* Success! */
|
||||
}
|
||||
|
||||
bool
|
||||
CreateDataDirLockFile(const char *datadir, bool amPostmaster)
|
||||
{
|
||||
char lockfile[MAXPGPATH];
|
||||
int encoded_pid;
|
||||
|
||||
snprintf(lockfile, sizeof(lockfile), "%s/postmaster.pid", datadir);
|
||||
encoded_pid = CreateLockFile(lockfile, amPostmaster);
|
||||
if (encoded_pid != 0)
|
||||
{
|
||||
fprintf(stderr, "Lock file \"%s\" already exists.\n", lockfile);
|
||||
if (encoded_pid < 0)
|
||||
fprintf(stderr, "Is another postgres (pid %d) running in \"%s\"?\n",
|
||||
-encoded_pid, datadir);
|
||||
else
|
||||
fprintf(stderr, "Is another postmaster (pid %d) running in \"%s\"?\n",
|
||||
encoded_pid, datadir);
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
bool
|
||||
CreateSocketLockFile(const char *socketfile, bool amPostmaster)
|
||||
{
|
||||
char lockfile[MAXPGPATH];
|
||||
int encoded_pid;
|
||||
|
||||
snprintf(lockfile, sizeof(lockfile), "%s.lock", socketfile);
|
||||
encoded_pid = CreateLockFile(lockfile, amPostmaster);
|
||||
if (encoded_pid != 0)
|
||||
{
|
||||
fprintf(stderr, "Lock file \"%s\" already exists.\n", lockfile);
|
||||
if (encoded_pid < 0)
|
||||
fprintf(stderr, "Is another postgres (pid %d) using \"%s\"?\n",
|
||||
-encoded_pid, socketfile);
|
||||
else
|
||||
fprintf(stderr, "Is another postmaster (pid %d) using \"%s\"?\n",
|
||||
encoded_pid, socketfile);
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
||||
/*-------------------------------------------------------------------------
|
||||
* Version checking support
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
|
||||
/*
|
||||
* Determine whether the PG_VERSION file in directory `path' indicates
|
||||
@ -628,12 +654,12 @@ ValidatePgVersion(const char *path)
|
||||
if (errno == ENOENT)
|
||||
elog(FATAL, "File %s is missing. This is not a valid data directory.", full_path);
|
||||
else
|
||||
elog(FATAL, "cannot open %s: %s", full_path, strerror(errno));
|
||||
elog(FATAL, "cannot open %s: %m", full_path);
|
||||
}
|
||||
|
||||
ret = fscanf(file, "%ld.%ld", &file_major, &file_minor);
|
||||
if (ret == EOF)
|
||||
elog(FATAL, "cannot read %s: %s", full_path, strerror(errno));
|
||||
elog(FATAL, "cannot read %s: %m", full_path);
|
||||
else if (ret != 2)
|
||||
elog(FATAL, "`%s' does not have a valid format. You need to initdb.", full_path);
|
||||
|
||||
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Reference in New Issue
Block a user