Fix pg_ctl crash on "unregister" when a data directory is not specified.

by Magnus Hagander

diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index d2d866d1303c4e91645098b04325bc7513bc6db8..eff141fcb1067882dee2c4d2839c1093a35a6092 100644 (file)
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -117,6 +117,7 @@ static pgpid_t get_pgpid(void);
 static char **readfile(const char *path);
 static int     start_postmaster(void);
 static bool test_postmaster_connection(void);
+static bool postmaster_is_alive(pid_t pid);
 
 static char def_postopts_file[MAXPGPATH];
 static char postopts_file[MAXPGPATH];
@@ -237,7 +238,7 @@ static pgpid_t
 get_pgpid(void)
 {
        FILE       *pidf;
-       pgpid_t         pid;
+       long            pid;
 
        pidf = fopen(pid_file, "r");
        if (pidf == NULL)
@@ -247,14 +248,19 @@ get_pgpid(void)
                        return 0;
                else
                {
-                       write_stderr(_("%s: could not open PID file \"%s\": %s"),
+                       write_stderr(_("%s: could not open PID file \"%s\": %s\n"),
                                                 progname, pid_file, strerror(errno));
                        exit(1);
                }
        }
-       fscanf(pidf, "%ld", &pid);
+       if (fscanf(pidf, "%ld", &pid) != 1)
+       {
+               write_stderr(_("%s: invalid data in PID file \"%s\"\n"),
+                                        progname, pid_file);
+               exit(1);
+       }
        fclose(pidf);
-       return pid;
+       return (pgpid_t) pid;
 }
 
 
@@ -675,7 +681,8 @@ do_restart(void)
 
        if (pid == 0)                           /* no pid file */
        {
-               write_stderr(_("%s: PID file \"%s\" does not exist\n"), progname, pid_file);
+               write_stderr(_("%s: PID file \"%s\" does not exist\n"),
+                                        progname, pid_file);
                write_stderr(_("Is postmaster running?\n"));
                write_stderr(_("starting postmaster anyway\n"));
                do_start();
@@ -684,45 +691,58 @@ do_restart(void)
        else if (pid < 0)                       /* standalone backend, not postmaster */
        {
                pid = -pid;
-               write_stderr(_("%s: cannot restart postmaster; "
-                                          "postgres is running (PID: %ld)\n"),
-                                        progname, pid);
-               write_stderr(_("Please terminate postgres and try again.\n"));
-               exit(1);
+               if (postmaster_is_alive((pid_t) pid))
+               {
+                       write_stderr(_("%s: cannot restart postmaster; "
+                                                  "postgres is running (PID: %ld)\n"),
+                                                progname, pid);
+                       write_stderr(_("Please terminate postgres and try again.\n"));
+                       exit(1);
+               }
        }
 
-       if (kill((pid_t) pid, sig) != 0)
+       if (postmaster_is_alive((pid_t) pid))
        {
-               write_stderr(_("%s: could not send stop signal (PID: %ld): %s\n"), progname, pid,
-                                        strerror(errno));
-               exit(1);
-       }
+               if (kill((pid_t) pid, sig) != 0)
+               {
+                       write_stderr(_("%s: could not send stop signal (PID: %ld): %s\n"), progname, pid,
+                                                strerror(errno));
+                       exit(1);
+               }
 
-       print_msg(_("waiting for postmaster to shut down..."));
+               print_msg(_("waiting for postmaster to shut down..."));
 
        /* always wait for restart */
 
-       for (cnt = 0; cnt < wait_seconds; cnt++)
-       {
-               if ((pid = get_pgpid()) != 0)
+               for (cnt = 0; cnt < wait_seconds; cnt++)
                {
-                       print_msg(".");
-                       pg_usleep(1000000); /* 1 sec */
+                       if ((pid = get_pgpid()) != 0)
+                       {
+                               print_msg(".");
+                               pg_usleep(1000000); /* 1 sec */
+                       }
+                       else
+                               break;
                }
-               else
-                       break;
-       }
 
-       if (pid != 0)                           /* pid file still exists */
-       {
-               print_msg(_(" failed\n"));
+               if (pid != 0)                           /* pid file still exists */
+               {
+                       print_msg(_(" failed\n"));
 
-               write_stderr(_("%s: postmaster does not shut down\n"), progname);
-               exit(1);
+                       write_stderr(_("%s: postmaster does not shut down\n"), progname);
+                       exit(1);
+               }
+
+               print_msg(_(" done\n"));
+               printf(_("postmaster stopped\n"));
+       }
+       else
+       {
+               write_stderr(_("%s: old postmaster process (PID: %ld) seems to be gone\n"),
+                                        progname, pid);
+               write_stderr(_("starting postmaster anyway\n"));
        }
 
-       print_msg(_(" done\n"));
-       printf(_("postmaster stopped\n"));
        do_start();
 }
 
@@ -763,34 +783,67 @@ do_reload(void)
  *     utility routines
  */
 
+static bool
+postmaster_is_alive(pid_t pid)
+{
+       /*
+        * Test to see if the process is still there.  Note that we do not
+        * consider an EPERM failure to mean that the process is still there;
+        * EPERM must mean that the given PID belongs to some other userid,
+        * and considering the permissions on $PGDATA, that means it's not
+        * the postmaster we are after.
+        *
+        * Don't believe that our own PID or parent shell's PID is the postmaster,
+        * either.  (Windows hasn't got getppid(), though.)
+        */
+       if (pid == getpid())
+               return false;
+#ifndef WIN32
+       if (pid == getppid())
+               return false;
+#endif
+       if (kill(pid, 0) == 0)
+               return true;
+       return false;
+}
+
 static void
 do_status(void)
 {
        pgpid_t         pid;
 
        pid = get_pgpid();
-       if (pid == 0)                           /* no pid file */
-       {
-               printf(_("%s: neither postmaster nor postgres running\n"), progname);
-               exit(1);
-       }
-       else if (pid < 0)                       /* standalone backend */
-       {
-               pid = -pid;
-               printf(_("%s: a standalone backend \"postgres\" is running (PID: %ld)\n"), progname, pid);
-       }
-       else
-       /* postmaster */
+       if (pid != 0)                           /* 0 means no pid file */
        {
-               char      **optlines;
+               if (pid < 0)                    /* standalone backend */
+               {
+                       pid = -pid;
+                       if (postmaster_is_alive((pid_t) pid))
+                       {
+                               printf(_("%s: a standalone backend \"postgres\" is running (PID: %ld)\n"),
+                                          progname, pid);
+                               return;
+                       }
+               }
+               else                                    /* postmaster */
+               {
+                       if (postmaster_is_alive((pid_t) pid))
+                       {
+                               char      **optlines;
 
-               printf(_("%s: postmaster is running (PID: %ld)\n"), progname, pid);
+                               printf(_("%s: postmaster is running (PID: %ld)\n"),
+                                          progname, pid);
 
-               optlines = readfile(postopts_file);
-               if (optlines != NULL)
-                       for (; *optlines != NULL; optlines++)
-                               fputs(*optlines, stdout);
+                               optlines = readfile(postopts_file);
+                               if (optlines != NULL)
+                                       for (; *optlines != NULL; optlines++)
+                                               fputs(*optlines, stdout);
+                               return;
+                       }
+               }
        }
+       printf(_("%s: neither postmaster nor postgres running\n"), progname);
+       exit(1);
 }
 
 
@@ -800,8 +853,8 @@ do_kill(pgpid_t pid)
 {
        if (kill((pid_t) pid, sig) != 0)
        {
-               write_stderr(_("%s: could not send signal %d (PID: %ld): %s\n"), progname, sig, pid,
-                                        strerror(errno));
+               write_stderr(_("%s: could not send signal %d (PID: %ld): %s\n"),
+                                        progname, sig, pid, strerror(errno));
                exit(1);
        }
 }
@@ -1465,10 +1518,13 @@ main(int argc, char **argv)
                do_wait = false;
        }
 
-       snprintf(def_postopts_file, MAXPGPATH, "%s/postmaster.opts.default", pg_data);
-       snprintf(postopts_file, MAXPGPATH, "%s/postmaster.opts", pg_data);
-       snprintf(pid_file, MAXPGPATH, "%s/postmaster.pid", pg_data);
-       snprintf(conf_file, MAXPGPATH, "%s/postgresql.conf", pg_data);
+       if (pg_data != NULL)
+       {
+               snprintf(def_postopts_file, MAXPGPATH, "%s/postmaster.opts.default", pg_data);
+               snprintf(postopts_file, MAXPGPATH, "%s/postmaster.opts", pg_data);
+               snprintf(pid_file, MAXPGPATH, "%s/postmaster.pid", pg_data);
+               snprintf(conf_file, MAXPGPATH, "%s/postgresql.conf", pg_data);
+       }
 
        switch (ctl_command)
        {