===================================================================
@@ -505,6 +505,7 @@ pex_read_err (struct pex_obj *obj, int b
if (o < 0 || o == STDIN_FILE_NO)
return NULL;
obj->read_err = obj->funcs->fdopenr (obj, o, binary);
+ obj->stderr_pipe = -1;
return obj->read_err;
}
@@ -597,8 +598,17 @@ pex_get_times (struct pex_obj *obj, int
void
pex_free (struct pex_obj *obj)
{
+ /* Close pipe file descriptors corresponding to child's stdout and
+ stderr so that the child does not hang trying to output anything
+ while we're waiting for it. */
if (obj->next_input >= 0 && obj->next_input != STDIN_FILE_NO)
obj->funcs->close (obj, obj->next_input);
+ if (obj->stderr_pipe >= 0 && obj->stderr_pipe != STDIN_FILE_NO)
+ obj->funcs->close (obj, obj->stderr_pipe);
+ if (obj->read_output != NULL)
+ fclose (obj->read_output);
+ if (obj->read_err != NULL)
+ fclose (obj->read_err);
/* If the caller forgot to wait for the children, we do it here, to
avoid zombies. */
@@ -619,10 +629,6 @@ pex_free (struct pex_obj *obj)
free (obj->status);
if (obj->time != NULL)
free (obj->time);
- if (obj->read_output != NULL)
- fclose (obj->read_output);
- if (obj->read_err != NULL)
- fclose (obj->read_err);
if (obj->remove_count > 0)
{
Hi, The change I proposed here: http://gcc.gnu.org/ml/gcc-patches/2009-12/msg01089.html http://gcc.gnu.org/ml/gcc-patches/2010-04/msg01214.html has been reviewed by Mark Mitchell off the list and so I have applied it now. For a reference I'm including the original submission below. Maciej ---------- Forwarded message ---------- Message-ID: <alpine.DEB.1.10.0912181134140.4720@tp.orcam.me.uk> Date: Wed, 23 Dec 2009 19:25:13 +0000 (GMT) From: Maciej W. Rozycki <macro@codesourcery.com> To: gcc-patches@gcc.gnu.org Cc: gdb-patches@sourceware.org, Maciej W. Rozycki <macro@linux-mips.org> Subject: [PATCH] GDB/libiberty: Mingw32 remote debug hang on close Hello, Noticed while debugging a remote target using pipes to communicate with a debug stub both running on a Mingw32 host. When a debug session is terminated from the GDB side, like with: (gdb) kill and the stub outputs any data to its stderr file descriptor (such as diagnostic information) afterwards before it terminates, then both programs hang. I have tracked down the cause to be the parent pipe descriptor corresponding to child's stderr having been left open while a wait() call is made in the parent to await child's termination. Meanwhile the child would keep producing diagnostic output to its stderr up till the exhaustion of the pipe system buffer at which point the child would hang as the parent busy with the wait() would not pay attention to its corresponding descriptor anymore. Here's a change that works for me. It makes sure the parent pipe descriptors corresponding to child's stderr and stdout are closed before the call to wait() is made, making any writes to these pipes in the child fail straight away. 2009-12-23 Maciej W. Rozycki <macro@codesourcery.com> libiberty/ * pex-common.c (pex_read_err): Set stderr_pipe to -1 if a corresponding stream has been opened. (pex_free): Close pipe file descriptors corresponding to child's stdout and stderr before waiting. Regression tested successfully with GDB testsuite the i386-mingw32 host and the mips-sde-elf target, using QEMU as the remote system. OK to apply? Maciej gdb-6.8.50-20091205-pex-free-0.patch