Re: [BUGS] BUG #2195: log_min_messages crash server when in DEBUG3 to - Mailing list pgsql-patches

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > The problem is that for EXEC_BACKEND, which is the default for WIN32 and
> > what I used for testing, progname is NULL because we do not set it after
> > the fork/exec.  Most versions of printf report "(null)" for a null
> > argument to printf("%s"), but our port/snprintf.c version aborts, which
> > is probably better in terms of finding bugs.
>
> Good catch.
>
> > The attached patch fixes the problem by setting progname early in
> > main(), like we do for all other applications.
>
> It'd probably be best to strdup() argv[0], because of the likelihood
> that the argv area will get clobbered at some point by ps_status.c.
> It was OK to have a private static in postmaster.c, because the
> postmaster doesn't ever call ps_status.c, but if we are going to expose
> the variable in child processes it needs to be more globally valid.
>
> I see that get_progname strdup's its argument in some cases but not
> all --- so simplest fix is to make it always do so.

OK, new version that updates get_progname to always strdup().

--
  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
Index: src/backend/main/main.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/main/main.c,v
retrieving revision 1.99
diff -c -c -r1.99 main.c
*** src/backend/main/main.c    5 Jan 2006 03:01:34 -0000    1.99
--- src/backend/main/main.c    31 Jan 2006 21:03:01 -0000
***************
*** 45,51 ****
  #include "libpq/pqsignal.h"
  #endif

!

  int
  main(int argc, char *argv[])
--- 45,51 ----
  #include "libpq/pqsignal.h"
  #endif

! const char *progname;

  int
  main(int argc, char *argv[])
***************
*** 77,82 ****
--- 77,84 ----
      char       *env_locale;
  #endif

+     progname = get_progname(argv[0]);
+
      /*
       * On some platforms, unaligned memory accesses result in a kernel trap;
       * the default kernel behavior is to emulate the memory access, but this
***************
*** 246,252 ****
       * possibly first argument) we were called with. The lack of consistency
       * here is historical.
       */
!     if (strcmp(get_progname(argv[0]), "postmaster") == 0)
      {
          /* Called as "postmaster" */
          exit(PostmasterMain(argc, argv));
--- 248,254 ----
       * possibly first argument) we were called with. The lack of consistency
       * here is historical.
       */
!     if (strcmp(progname, "postmaster") == 0)
      {
          /* Called as "postmaster" */
          exit(PostmasterMain(argc, argv));
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v
retrieving revision 1.479
diff -c -c -r1.479 postmaster.c
*** src/backend/postmaster/postmaster.c    6 Jan 2006 02:58:25 -0000    1.479
--- src/backend/postmaster/postmaster.c    31 Jan 2006 21:03:04 -0000
***************
*** 171,179 ****
   */
  int            ReservedBackends;

-
- static const char *progname = NULL;
-
  /* The socket(s) we're listening to. */
  #define MAXLISTEN    64
  static int    ListenSocket[MAXLISTEN];
--- 171,176 ----
***************
*** 383,391 ****
      char       *userDoption = NULL;
      int            i;

-     /* This will call exit() if strdup() fails. */
-     progname = get_progname(argv[0]);
-
      MyProcPid = PostmasterPid = getpid();

      IsPostmasterEnvironment = true;
--- 380,385 ----
Index: src/include/postmaster/postmaster.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/postmaster/postmaster.h,v
retrieving revision 1.11
diff -c -c -r1.11 postmaster.h
*** src/include/postmaster/postmaster.h    20 Aug 2005 23:26:33 -0000    1.11
--- src/include/postmaster/postmaster.h    31 Jan 2006 21:03:06 -0000
***************
*** 34,39 ****
--- 34,40 ----
  extern HANDLE PostmasterHandle;
  #endif

+ extern const char *progname;

  extern int    PostmasterMain(int argc, char *argv[]);
  extern void ClosePostmasterPorts(bool am_syslogger);
Index: src/port/path.c
===================================================================
RCS file: /cvsroot/pgsql/src/port/path.c,v
retrieving revision 1.63
diff -c -c -r1.63 path.c
*** src/port/path.c    23 Dec 2005 22:34:22 -0000    1.63
--- src/port/path.c    31 Jan 2006 21:03:06 -0000
***************
*** 388,394 ****
  const char *
  get_progname(const char *argv0)
  {
!     const char *nodir_name;

      nodir_name = last_dir_separator(argv0);
      if (nodir_name)
--- 388,395 ----
  const char *
  get_progname(const char *argv0)
  {
!     const char  *nodir_name;
!     const char    *progname;

      nodir_name = last_dir_separator(argv0);
      if (nodir_name)
***************
*** 396,420 ****
      else
          nodir_name = skip_drive(argv0);

! #if defined(__CYGWIN__) || defined(WIN32)
!     /* strip .exe suffix, regardless of case */
!     if (strlen(nodir_name) > sizeof(EXE) - 1 &&
!         pg_strcasecmp(nodir_name + strlen(nodir_name) - (sizeof(EXE) - 1), EXE) == 0)
      {
!         char       *progname;

!         progname = strdup(nodir_name);    /* leaks memory, but called only once */
!         if (progname == NULL)
!         {
!             fprintf(stderr, "%s: out of memory\n", nodir_name);
!             exit(1);            /* This could exit the postmaster */
!         }
          progname[strlen(progname) - (sizeof(EXE) - 1)] = '\0';
-         nodir_name = progname;
-     }
  #endif

!     return nodir_name;
  }


--- 397,421 ----
      else
          nodir_name = skip_drive(argv0);

!     /*
!      *    Make a copy in case argv[0] is modified by ps_status.
!      *    Leaks memory, but called only once.
!      */
!     progname = strdup(nodir_name);
!     if (progname == NULL)
      {
!         fprintf(stderr, "%s: out of memory\n", nodir_name);
!         exit(1);            /* This could exit the postmaster */
!     }

! #if defined(__CYGWIN__) || defined(WIN32)
!     /* strip ".exe" suffix, regardless of case */
!     if (strlen(progname) > sizeof(EXE) - 1 &&
!         pg_strcasecmp(progname + strlen(progname) - (sizeof(EXE) - 1), EXE) == 0)
          progname[strlen(progname) - (sizeof(EXE) - 1)] = '\0';
  #endif

!     return progname;
  }