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 
 #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);
+}