Re: [HACKERS] Win32 WEXITSTATUS too simplistic - Mailing list pgsql-patches

I did some research on this, and found a nice Win32 list of STATUS_
error values.  Looking at the list, I think the non-exit() return values
are much larger than just the second high bit.

I am proposing the attached patch, which basically has all system()
return values < 0x100 as exit() calls, and everything above that as a
signal exits.  I also think it is too risky to backpatch to 8.2.X.

Also, should we print Win32 WTERMSIG() values as hex because they are so
large?  I have added that to the patch.

---------------------------------------------------------------------------

ITAGAKI Takahiro wrote:
>
> Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> >     server process exited with exit code -1073741819
> > from what I suspect is really the equivalent of a SIGSEGV trap,
> > ie, attempted access to already-deallocated memory.  My calculator
> > says the above is equivalent to hex C0000005, and I say that this
> > makes it pretty clear that *some* parts of Windows put flag bits into
> > the process exit code.  Anyone want to run down what we should really
> > be using instead of the above macros?
>
> C0000005 equals to EXCEPTION_ACCESS_VIOLATION. The value returned by
> GetExceptionCode() seems to be the exit code in unhandeled exception cases.
>
> AFAICS, all EXCEPTION_xxx (or STATUS_xxx) values are defined as 0xCxxxxxxx.
> I think we can use the second high bit to distinguish exit by exception
> from normal exits.
>
> #define WEXITSTATUS(w)  ((int) ((w) & 0x40000000))
> #define WIFEXITED(w)    ((w) & 0x40000000) == 0)
> #define WIFSIGNALED(w)  ((w) & 0x40000000) != 0)
> #define WTERMSIG(w)     (w) // or ((w) & 0x3FFFFFFF)
>
> However, it comes from reverse engineering of the headers of Windows.
> I cannot find any official documentation.
>
> Regards,
> ---
> ITAGAKI Takahiro
> NTT Open Source Software Center
>
>
>
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--
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +
Index: src/backend/postmaster/postmaster.c
===================================================================
RCS file: /cvsroot/pgsql/src/backend/postmaster/postmaster.c,v
retrieving revision 1.508
diff -c -c -r1.508 postmaster.c
*** src/backend/postmaster/postmaster.c    16 Jan 2007 13:28:56 -0000    1.508
--- src/backend/postmaster/postmaster.c    22 Jan 2007 04:51:01 -0000
***************
*** 2426,2432 ****
          /*------
            translator: %s is a noun phrase describing a child process, such as
            "server process" */
!                 (errmsg("%s (PID %d) was terminated by signal %d",
                          procname, pid, WTERMSIG(exitstatus))));
      else
          ereport(lev,
--- 2426,2432 ----
          /*------
            translator: %s is a noun phrase describing a child process, such as
            "server process" */
!                 (errmsg("%s (PID %d) was terminated by signal "PRINTF_SIGNUM,
                          procname, pid, WTERMSIG(exitstatus))));
      else
          ereport(lev,
Index: src/include/c.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/c.h,v
retrieving revision 1.216
diff -c -c -r1.216 c.h
*** src/include/c.h    11 Jan 2007 02:39:52 -0000    1.216
--- src/include/c.h    22 Jan 2007 04:51:02 -0000
***************
*** 788,793 ****
--- 788,800 ----
  #define SIGNAL_ARGS  int postgres_signal_arg
  #endif

+ #ifndef WIN32
+ #define PRINTF_SIGNUM    "%d"
+ #else
+ /* Win32 non-exit system() return values are high, see port/win32.h */
+ #define PRINTF_SIGNUM    "%X"
+ #endif
+
  /*
   * When there is no sigsetjmp, its functionality is provided by plain
   * setjmp. Incidentally, nothing provides setjmp's functionality in
Index: src/include/port/win32.h
===================================================================
RCS file: /cvsroot/pgsql/src/include/port/win32.h,v
retrieving revision 1.65
diff -c -c -r1.65 win32.h
*** src/include/port/win32.h    11 Jan 2007 02:42:31 -0000    1.65
--- src/include/port/win32.h    22 Jan 2007 04:51:02 -0000
***************
*** 115,130 ****

  /*
   *    Signal stuff
!  *    WIN32 doesn't have wait(), so the return value for children
!  *    is simply the return value specified by the child, without
!  *    any additional information on whether the child terminated
!  *    on its own or via a signal.  These macros are also used
!  *    to interpret the return value of system().
!  */
! #define WEXITSTATUS(w)    (w)
! #define WIFEXITED(w)    (true)
! #define WIFSIGNALED(w)    (false)
! #define WTERMSIG(w)        (0)

  #define sigmask(sig) ( 1 << ((sig)-1) )

--- 115,134 ----

  /*
   *    Signal stuff
!  *    For WIN32, there is no wait() call so there are no wait() macros
!  *    to interpret the return value of system().  Instead, system()
!  *    return values < 0x100 are used for exit() termination, and higher
!  *    values are used to indicated non-exit() termination, which is
!  *    similar to a unix-style signal exit (think SIGSEGV ==
!  *    STATUS_ACCESS_VIOLATION).  See this URL for a list of WIN32
!  *    STATUS_* values from Wine:
!  *
!  *        http://source.winehq.org/source/include/ntstatus.h
!  */
! #define WIFEXITED(w)    (((w) & 0xffffff00) == 0)
! #define WIFSIGNALED(w)  (!WIFEXITED(w))
! #define WEXITSTATUS(w)  (w)
! #define WTERMSIG(w)     (w)

  #define sigmask(sig) ( 1 << ((sig)-1) )

Index: src/port/exec.c
===================================================================
RCS file: /cvsroot/pgsql/src/port/exec.c,v
retrieving revision 1.44
diff -c -c -r1.44 exec.c
*** src/port/exec.c    5 Jan 2007 22:20:02 -0000    1.44
--- src/port/exec.c    22 Jan 2007 04:51:03 -0000
***************
*** 582,588 ****
          log_error(_("child process exited with exit code %d"),
                    WEXITSTATUS(exitstatus));
      else if (WIFSIGNALED(exitstatus))
!         log_error(_("child process was terminated by signal %d"),
                    WTERMSIG(exitstatus));
      else
          log_error(_("child process exited with unrecognized status %d"),
--- 582,588 ----
          log_error(_("child process exited with exit code %d"),
                    WEXITSTATUS(exitstatus));
      else if (WIFSIGNALED(exitstatus))
!         log_error(_("child process was terminated by signal "PRINTF_SIGNUM),
                    WTERMSIG(exitstatus));
      else
          log_error(_("child process exited with unrecognized status %d"),