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tatsuo-ishiitatsuo-ishii
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Move SetPidFile() and firends to utils/init/miscinit.c from
postmaster/postmaster.c so that tcop/postgres.c can use them. Now we have an interlock between postmaster and postgres.
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‎src/backend/utils/init/miscinit.c

Lines changed: 155 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,12 +7,13 @@
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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 1.37 1999/11/24 16:52:42 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.38 2000/01/09 12:15:57 ishii Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <signal.h>
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#include <sys/stat.h>
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#include <sys/file.h>
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#include <unistd.h>
@@ -462,3 +463,156 @@ SetUserId()
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ShadowRelationName);
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UserId = (Oid) ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid;
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}
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/*-------------------------------------------------------------------------
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*
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* posmaster pid file stuffs. $DATADIR/postmaster.pid is created when:
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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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*
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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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*
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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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*/
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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 UnlinkPidFile(void)
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{
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unlink(PidFile);
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}
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/*
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* Set path to the pid file
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*/
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void 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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char *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 SetPidFile(pid_t pid)
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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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int len;
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pid_t post_pid;
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int is_postgres = 0;
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/*
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* Creating pid file
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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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/*
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* Couldn't create the pid file. Probably
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* it already exists. Read the file to see if the process
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* actually exists
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*/
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fd = open(pidfile, O_RDONLY, 0600);
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if (fd < 0) {
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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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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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}
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close(fd);
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/*
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* Check to see if the process actually 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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is_postgres++;
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post_pid = -post_pid;
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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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* No, the process did not exist. Unlink
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* the file and try to create it
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*/
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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");
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fprintf(stderr, "Please remove the file by hand and try again.\n");
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return(-1);
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}
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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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fprintf(stderr, "Can't create 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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} else {
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/*
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* Another postmaster is running
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*/
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fprintf(stderr, "Can't create pid file: %s\n", pidfile);
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if (is_postgres) {
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fprintf(stderr, "Is another postgres (pid: %d) running?\n", post_pid);
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}
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else
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{
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fprintf(stderr, "Is another postmaster (pid: %s) running?\n", pidstr);
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}
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return(-1);
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}
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}
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sprintf(pidstr, "%d", pid);
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if (write(fd, pidstr, strlen(pidstr)) != strlen(pidstr)) {
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fprintf(stderr,"Write to pid file failed\n");
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fprintf(stderr, "Please check the permission and try again.\n");
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close(fd);
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unlink(pidfile);
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return(-1);
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}
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close(fd);
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return(0);
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}

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