[Bug gdb/18653] New: spawn changes SIGPIPE SIG_DFL to SIG_IGN

[Bug gdb/18653] New: spawn changes SIGPIPE SIG_DFL to SIG_IGN

[jan.kratochvil at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=18653

            Bug ID: 18653
           Summary: spawn changes SIGPIPE SIG_DFL to SIG_IGN
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: gdb
          Assignee: unassigned at sourceware dot org
          Reporter: jan.kratochvil at redhat dot com
  Target Milestone: ---

That is a program run under GDB "run" behaves differently than standalone.

standalone:                 SIG_DFL
GDB linux-nat:        FAIL: SIG_IGN
GDB gdbserver legacy: PASS: SIG_DFL
GDB gdbserver multi:  FAIL: SIG_IGN

-----------------------------------------
#define _GNU_SOURCE
#include <stdio.h>
#include <signal.h>
int main(void) {
  sighandler_t s=signal(SIGPIPE,SIG_DFL);
  if (s==SIG_DFL) puts("SIG_DFL");
  if (s==SIG_IGN) puts("SIG_IGN");
  return 0;
}

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[Bug gdb/18653] spawn changes SIGPIPE SIG_DFL to SIG_IGN

[ssbssa at sourceware dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=18653

Hannes Domani <ssbssa at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ssbssa at sourceware dot org

--- Comment #12 from Hannes Domani <ssbssa at sourceware dot org> ---
(In reply to Sourceware Commits from comment #10)
> The master branch has been updated by Pedro Alves <palves@sourceware.org>:
> 
> https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;
> h=e379cee61f3890e535e995828e8846b020ef2a32
> 
> commit e379cee61f3890e535e995828e8846b020ef2a32
> Author: Pedro Alves <palves@redhat.com>
> Date:   Fri Jan 5 18:26:18 2018 +0000
> 
>     Fix regression: cannot start with LD_PRELOAD=libSegFault.so (PR
> gdb/18653#c7)
>     
>     At https://sourceware.org/bugzilla/show_bug.cgi?id=18653#c7, Andrew
>     reports that the fix for PR gdb/18653 made GDB useless if you preload
>     libSegFault.so, because GDB internal-errors on startup:
>     
>      $ LD_PRELOAD=libSegFault.so gdb
>      src/gdb/common/signals-state-save-restore.c:64: internal-error:
> unexpected signal handler
>      A problem internal to GDB has been detected,
>      further debugging may prove unreliable.
>      Aborted (core dumped)
>      $
>     
>     The internal error comes from the code saving the signal dispositions
>     inherited from gdb's parent:
>     
>      (top-gdb) bt
>      #0  0x000000000056b001 in internal_error(char const*, int, char const*,
> ...) (file=0xaf5f38 "src/gdb/common/signals-state-save-restore.c", line=64,
> fmt=0xaf5f18 "unexpected signal handler") at src/gdb/common/errors.c:54
>      #1  0x00000000005752c9 in save_original_signals_state() () at
> src/gdb/common/signals-state-save-restore.c:64
>      #2  0x00000000007425de in captured_main_1(captured_main_args*)
> (context=0x7fffffffd860)
>          at src/gdb/main.c:509
>      #3  0x0000000000743622 in captured_main(void*) (data=0x7fffffffd860) at
> src/gdb/main.c:1145
>      During symbol reading, cannot get low and high bounds for subprogram
> DIE at 24065.
>      #4  0x00000000007436f9 in gdb_main(captured_main_args*)
> (args=0x7fffffffd860) at src/gdb/main.c:1171
>      #5  0x0000000000413acd in main(int, char**) (argc=1,
> argv=0x7fffffffd968) at src/gdb/gdb.c:32
>     
>     This commit downgrades the internal error to a warning.  You'll get
>     instead:
>     
>     ~~~
>      $ LD_PRELOAD=libSegFault.so gdb
>      warning: Found custom handler for signal 11 (Segmentation fault)
> preinstalled.
>      Some signal dispositions inherited from the environment
> (SIG_DFL/SIG_IGN)
>      won't be propagated to spawned programs.
>      GNU gdb (GDB) 8.0.50.20171213-git
>      Copyright (C) 2017 Free Software Foundation, Inc.
>      License GPLv3+: GNU GPL version 3 or later
> <http://gnu.org/licenses/gpl.html>
>      This is free software: you are free to change and redistribute it.
>      There is NO WARRANTY, to the extent permitted by law.  Type "show
> copying"
>      and "show warranty" for details.
>      This GDB was configured as "x86_64-pc-linux-gnu".
>      Type "show configuration" for configuration details.
>      For bug reporting instructions, please see:
>      <http://www.gnu.org/software/gdb/bugs/>.
>      Find the GDB manual and other documentation resources online at:
>      <http://www.gnu.org/software/gdb/documentation/>.
>      For help, type "help".
>      Type "apropos word" to search for commands related to "word"...
>      (gdb)
>     ~~~
>     
>     This also moves the location where save_original_signals_state is
>     called a bit further below (to after option processing), so that "-q"
>     disables the warning:
>     
>     ~~~
>      $ LD_PRELOAD=libSegFault.so gdb -q
>      (gdb)
>     ~~~
>     
>     New testcase included.
>     
>     gdb/ChangeLog:
>     2018-01-05  Pedro Alves  <palves@redhat.com>
>     
>     	PR gdb/18653
>     	* common/signals-state-save-restore.c
>     	(save_original_signals_state): New parameter 'quiet'.  Warn if we
>     	find a custom handler preinstalled, instead of internal erroring.
>     	But only warn if !quiet.
>     	* common/signals-state-save-restore.h
>     	(save_original_signals_state): New parameter 'quiet'.
>     	* main.c (captured_main_1): Move save_original_signals_state call
>     	after option handling, and pass QUIET.
>     
>     gdb/gdbserver/ChangeLog:
>     2018-01-05  Pedro Alves  <palves@redhat.com>
>     
>     	PR gdb/18653
>     	* server.c (captured_main): Pass quiet=false to
>     	save_original_signals_state.
>     
>     gdb/testsuite/ChangeLog:
>     2018-01-05  Pedro Alves  <palves@redhat.com>
>     
>     	PR gdb/18653
>     	* gdb.base/libsegfault.exp: New.

Can this be closed?

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[Bug gdb/18653] spawn changes SIGPIPE SIG_DFL to SIG_IGN

[pinskia at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=18653

--- Comment #13 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Hannes Domani from comment #12)
> Can this be closed?

From my point of view, it is fixed.

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