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.

diff --git a/src/backend/utils/init/miscinit.c b/src/backend/utils/init/miscinit.c
index 18eed64195f73236c0f893ecac9bb21782dd8c98..1de751e950ffc05c03594532b70d9c6e4d5e66f9 100644 (file)
--- 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 <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);
+}