On Thu, 12 Aug 2021 16:16:04 -0700
Ian Lance Taylor <iant@google.com> wrote:

> On Thu, Aug 12, 2021 at 3:34 PM Sergei Trofimovich via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > From: Sergei Trofimovich <siarheit@google.com>
> >
> > I noticed test failures when ran gcc test suite from under mc shell.
> > mc opens fd=9 and exposes it to child processes. As a result a few
> > tests failes:
> >     FAIL: b2test_buildid
> >     FAIL: btest_gnudebuglink
> >     FAIL: btest
> >     FAIL: btest_lto
> >     FAIL: btest_alloc
> >     FAIL: ctestg
> >     FAIL: ctesta
> >     FAIL: ctestg_alloc
> >     FAIL: ctesta_alloc
> >     FAIL: dwarf5
> >     FAIL: dwarf5_alloc
> >
> > Instead of trying to close file descripts in range test polls for
> > first available file descriptor by creating it via dup(1).
> >
> > libbacktrace/
> >
> >         * btest.c (check_open_files): Use last free file descriptor as a
> >         signal for flie descriptor leak.  
> 
> This isn't a useful replacement, as this will pass as long as
> libbacktrace closes the first file descriptor that it opens.  It won't
> check whether libbacktrace left any other file descriptors open.
> 
> Perhaps at program startup we could fstat descriptors up to 10 and
> record whether they are valid, and then skip those files in
> check_open_files.

Oh, great point! Completely missed it. Changed the patch to poll for present
file descriptors with fcntl(fd, F_GETFD) to compare before/after.

-- 

  Sergei