From 10283ee6a4c92a4db503504cbc567876732dbd49 Mon Sep 17 00:00:00 2001 From: Tatsuo Ishii Date: Sun, 9 Jan 2000 12:15:57 +0000 Subject: [PATCH] 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. --- src/backend/utils/init/miscinit.c | 156 +++++++++++++++++++++++++++++- 1 file changed, 155 insertions(+), 1 deletion(-) diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c index 18eed64195..1de751e950 100644 --- a/src/backend/utils/init/miscinit.c +++ b/src/backend/utils/init/miscinit.c @@ -7,12 +7,13 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.37 1999/11/24 16:52:42 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/init/miscinit.c,v 1.38 2000/01/09 12:15:57 ishii Exp $ * *------------------------------------------------------------------------- */ #include #include +#include #include #include #include @@ -462,3 +463,156 @@ SetUserId() ShadowRelationName); UserId = (Oid) ((Form_pg_shadow) GETSTRUCT(userTup))->usesysid; } + +/*------------------------------------------------------------------------- + * + * posmaster pid file stuffs. $DATADIR/postmaster.pid is created when: + * + * (1) postmaster starts. In this case pid > 0. + * (2) postgres starts in standalone mode. In this case + * pid < 0 + * + * to gain an interlock. + * + * SetPidFname(datadir) + * Remember the the pid file name. This is neccesary + * UnlinkPidFile() is called from proc_exit(). + * + * GetPidFname(datadir) + * Get the pid file name. SetPidFname() should be called + * before GetPidFname() gets called. + * + * UnlinkPidFile() + * This is called from proc_exit() and unlink the pid file. + * + * SetPidFile(pid_t pid) + * Create the pid file. On failure, it checks if the process + * actually exists or not. SetPidFname() should be called + * in prior to calling SetPidFile(). + * + *------------------------------------------------------------------------- + */ + +/* + * Path to pid file. proc_exit() remember it to unlink the file. + */ +static char PidFile[MAXPGPATH]; + +/* + * Remove the pid file. This function is called from proc_exit. + */ +void UnlinkPidFile(void) +{ + unlink(PidFile); +} + +/* + * Set path to the pid file + */ +void SetPidFname(char * datadir) +{ + snprintf(PidFile, sizeof(PidFile), "%s/%s", datadir, PIDFNAME); +} + +/* + * Get path to the pid file + */ +char *GetPidFname(void) +{ + return(PidFile); +} + +/* + * Create the pid file + */ +int SetPidFile(pid_t pid) +{ + int fd; + char *pidfile; + char pidstr[32]; + int len; + pid_t post_pid; + int is_postgres = 0; + + /* + * Creating pid file + */ + pidfile = GetPidFname(); + fd = open(pidfile, O_RDWR | O_CREAT | O_EXCL, 0600); + if (fd < 0) { + /* + * Couldn't create the pid file. Probably + * it already exists. Read the file to see if the process + * actually exists + */ + fd = open(pidfile, O_RDONLY, 0600); + if (fd < 0) { + fprintf(stderr, "Can't open pid file: %s\n", pidfile); + fprintf(stderr, "Please check the permission and try again.\n"); + return(-1); + } + if ((len = read(fd, pidstr, sizeof(pidstr)-1)) < 0) { + fprintf(stderr, "Can't read pid file: %s\n", pidfile); + fprintf(stderr, "Please check the permission and try again.\n"); + close(fd); + return(-1); + } + close(fd); + + /* + * Check to see if the process actually exists + */ + pidstr[len] = '\0'; + post_pid = (pid_t)atoi(pidstr); + + /* if pid < 0, the pid is for postgres, not postmatser */ + if (post_pid < 0) { + is_postgres++; + post_pid = -post_pid; + } + + if (post_pid == 0 || (post_pid > 0 && kill(post_pid, 0) < 0)) { + /* + * No, the process did not exist. Unlink + * the file and try to create it + */ + if (unlink(pidfile) < 0) { + fprintf(stderr, "Can't remove pid file: %s\n", pidfile); + 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"); + return(-1); + } + 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", post_pid); + } + else + { + fprintf(stderr, "Is another postmaster (pid: %s) running?\n", pidstr); + } + return(-1); + } + } + + sprintf(pidstr, "%d", pid); + if (write(fd, pidstr, strlen(pidstr)) != strlen(pidstr)) { + fprintf(stderr,"Write to pid file failed\n"); + fprintf(stderr, "Please check the permission and try again.\n"); + close(fd); + unlink(pidfile); + return(-1); + } + close(fd); + + return(0); +}