Re: [HACKERS] New pg_ctl has retrogressed in error messages - Mailing list pgsql-patches

Andrew Dunstan wrote:
>
> >this code will fail rather horribly if sizeof(pid_t) != sizeof(int).
> >Even more to the point, I believe a standalone backend will put
> >the negative of its PID into the file, and the revised code will fail
> >to parse that at all.
> >
> >I think the safest code would be like
> >
> >    long    tmp;
> >
> >    fscanf(pidf, "%ld", &tmp);
> >    if (tmp < 0)
> >    {
> >        tmp = -tmp;
> >        // do anything else needed for backend case
> >    }
> >    pid = (pid_t) tmp;
> >
> >
> >
> >
>
> I deliberately used a signed long for these reasons in the first place.
>
> The number of places we actually need to use this value as a pid is
> small (3 by my count - in calls to kill() ), and it was cast there to
> pid_t,  I think.  I still don't see what's wrong with that.

OK, I created a typedef pgpid_t equal to long and used that in the code,
change format to %ld, and documented why negative values are an issue.

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
? pg_ctl
Index: pg_ctl.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/bin/pg_ctl/pg_ctl.c,v
retrieving revision 1.2
diff -c -c -r1.2 pg_ctl.c
*** pg_ctl.c    31 May 2004 17:57:31 -0000    1.2
--- pg_ctl.c    1 Jun 2004 01:26:40 -0000
***************
*** 24,29 ****
--- 24,31 ----
  int            optreset;
  #endif

+ /* PID can be negative for standalone backend */
+ typedef long pgpid_t;

  #define _(x) gettext((x))

***************
*** 79,86 ****
  static void do_restart(void);
  static void do_reload(void);
  static void do_status(void);
! static void do_kill(pid_t pid);
! static pid_t get_pgpid(void);
  static char **readfile(char *path);
  static int start_postmaster(void);
  static bool test_postmaster_connection(void);
--- 81,88 ----
  static void do_restart(void);
  static void do_reload(void);
  static void do_status(void);
! static void do_kill(pgpid_t pid);
! static pgpid_t get_pgpid(void);
  static char **readfile(char *path);
  static int start_postmaster(void);
  static bool test_postmaster_connection(void);
***************
*** 126,136 ****



! static pid_t
  get_pgpid(void)
  {
      FILE       *pidf;
!     pid_t        pid;

      pidf = fopen(pid_file, "r");
      if (pidf == NULL)
--- 128,138 ----



! static pgpid_t
  get_pgpid(void)
  {
      FILE       *pidf;
!     pgpid_t        pid;

      pidf = fopen(pid_file, "r");
      if (pidf == NULL)
***************
*** 144,150 ****
              exit(1);
          }
      }
!     fscanf(pidf, "%u", &pid);
      fclose(pidf);
      return pid;
  }
--- 146,152 ----
              exit(1);
          }
      }
!     fscanf(pidf, "%ld", &pid);
      fclose(pidf);
      return pid;
  }
***************
*** 323,330 ****
  static void
  do_start(void)
  {
!     pid_t        pid;
!     pid_t        old_pid = 0;
      char       *optline = NULL;

      if (ctl_command != RESTART_COMMAND)
--- 325,332 ----
  static void
  do_start(void)
  {
!     pgpid_t        pid;
!     pgpid_t        old_pid = 0;
      char       *optline = NULL;

      if (ctl_command != RESTART_COMMAND)
***************
*** 457,463 ****
  do_stop(void)
  {
      int            cnt;
!     pid_t        pid;

      pid = get_pgpid();

--- 459,465 ----
  do_stop(void)
  {
      int            cnt;
!     pgpid_t        pid;

      pid = get_pgpid();

***************
*** 472,485 ****
          pid = -pid;
          fprintf(stderr,
                  _("%s: cannot stop postmaster; "
!                 "postgres is running (PID: %u)\n"),
                  progname, pid);
          exit(1);
      }

!     if (kill(pid, sig) != 0)
      {
!         fprintf(stderr, _("stop signal failed (PID: %u): %s\n"), pid,
                  strerror(errno));
          exit(1);
      }
--- 474,487 ----
          pid = -pid;
          fprintf(stderr,
                  _("%s: cannot stop postmaster; "
!                 "postgres is running (PID: %ld)\n"),
                  progname, pid);
          exit(1);
      }

!     if (kill((pid_t) pid, sig) != 0)
      {
!         fprintf(stderr, _("stop signal failed (PID: %ld): %s\n"), pid,
                  strerror(errno));
          exit(1);
      }
***************
*** 537,543 ****
  do_restart(void)
  {
      int            cnt;
!     pid_t        pid;

      pid = get_pgpid();

--- 539,545 ----
  do_restart(void)
  {
      int            cnt;
!     pgpid_t        pid;

      pid = get_pgpid();

***************
*** 553,567 ****
          pid = -pid;
          fprintf(stderr,
                  _("%s: cannot restart postmaster; "
!                 "postgres is running (PID: %u)\n"),
                  progname, pid);
          fprintf(stderr, _("Please terminate postgres and try again.\n"));
          exit(1);
      }

!     if (kill(pid, sig) != 0)
      {
!         fprintf(stderr, _("stop signal failed (PID: %u): %s\n"), pid,
                  strerror(errno));
          exit(1);
      }
--- 555,569 ----
          pid = -pid;
          fprintf(stderr,
                  _("%s: cannot restart postmaster; "
!                 "postgres is running (PID: %ld)\n"),
                  progname, pid);
          fprintf(stderr, _("Please terminate postgres and try again.\n"));
          exit(1);
      }

!     if (kill((pid_t) pid, sig) != 0)
      {
!         fprintf(stderr, _("stop signal failed (PID: %ld): %s\n"), pid,
                  strerror(errno));
          exit(1);
      }
***************
*** 609,615 ****
  static void
  do_reload(void)
  {
!     pid_t        pid;

      pid = get_pgpid();
      if (pid == 0)                /* no pid file */
--- 611,617 ----
  static void
  do_reload(void)
  {
!     pgpid_t        pid;

      pid = get_pgpid();
      if (pid == 0)                /* no pid file */
***************
*** 623,637 ****
          pid = -pid;
          fprintf(stderr,
                  _("%s: cannot reload postmaster; "
!                 "postgres is running (PID: %u)\n"),
                  progname, pid);
          fprintf(stderr, _("Please terminate postgres and try again.\n"));
          exit(1);
      }

!     if (kill(pid, sig) != 0)
      {
!         fprintf(stderr, _("reload signal failed (PID: %u): %s\n"), pid,
                  strerror(errno));
          exit(1);
      }
--- 625,639 ----
          pid = -pid;
          fprintf(stderr,
                  _("%s: cannot reload postmaster; "
!                 "postgres is running (PID: %ld)\n"),
                  progname, pid);
          fprintf(stderr, _("Please terminate postgres and try again.\n"));
          exit(1);
      }

!     if (kill((pid_t) pid, sig) != 0)
      {
!         fprintf(stderr, _("reload signal failed (PID: %ld): %s\n"), pid,
                  strerror(errno));
          exit(1);
      }
***************
*** 647,653 ****
  static void
  do_status(void)
  {
!     pid_t        pid;

      pid = get_pgpid();
      if (pid == 0)                /* no pid file */
--- 649,655 ----
  static void
  do_status(void)
  {
!     pgpid_t        pid;

      pid = get_pgpid();
      if (pid == 0)                /* no pid file */
***************
*** 658,670 ****
      else if (pid < 0)            /* standalone backend */
      {
          pid = -pid;
!         fprintf(stdout, _("%s: a standalone backend \"postgres\" is running (PID: %u)\n"), progname, pid);
      }
      else                        /* postmaster */
      {
          char      **optlines;

!         fprintf(stdout, _("%s: postmaster is running (PID: %u)\n"), progname, pid);

          optlines = readfile(postopts_file);
          if (optlines != NULL)
--- 660,672 ----
      else if (pid < 0)            /* standalone backend */
      {
          pid = -pid;
!         fprintf(stdout, _("%s: a standalone backend \"postgres\" is running (PID: %ld)\n"), progname, pid);
      }
      else                        /* postmaster */
      {
          char      **optlines;

!         fprintf(stdout, _("%s: postmaster is running (PID: %ld)\n"), progname, pid);

          optlines = readfile(postopts_file);
          if (optlines != NULL)
***************
*** 676,686 ****


  static void
! do_kill(pid_t pid)
  {
!     if (kill(pid, sig) != 0)
      {
!         fprintf(stderr, _("signal %d failed (PID: %u): %s\n"), sig, pid,
                  strerror(errno));
          exit(1);
      }
--- 678,688 ----


  static void
! do_kill(pgpid_t pid)
  {
!     if (kill((pid_t) pid, sig) != 0)
      {
!         fprintf(stderr, _("signal %d failed (PID: %ld): %s\n"), sig, pid,
                  strerror(errno));
          exit(1);
      }
***************
*** 813,819 ****

      int            option_index;
      int            c;
!     int            killproc = 0;

  #ifdef WIN32
      setvbuf(stderr, NULL, _IONBF, 0);
--- 815,821 ----

      int            option_index;
      int            c;
!     pgpid_t        killproc = 0;

  #ifdef WIN32
      setvbuf(stderr, NULL, _IONBF, 0);