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.
This commit is contained in:
Tatsuo Ishii 2000-01-09 12:15:57 +00:00
parent 3f3421f905
commit 10283ee6a4
1 changed files with 155 additions and 1 deletions

View File

@ -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 <sys/param.h>
#include <sys/types.h>
#include <signal.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <unistd.h>
@ -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);
}