view lib/freopen.c @ 15988:cd7ac59d8eb5

fts: close parent dir FD before returning from post-traversal fts_read The problem: the fts-using "mkdir -p A/B; rm -rf A" would attempt to unlink A, even though an FD open on A remained. This is suboptimal (holding a file descriptor open longer than needed), but otherwise not a problem on Unix-like kernels. However, on Cygwin with certain Novell file systems, (see http://cygwin.com/ml/cygwin/2011-10/msg00365.html), that represents a real problem: it causes the removal of A to fail with e.g., "rm: cannot remove `A': Device or resource busy" fts visits each directory twice and keeps a cache (fts_fd_ring) of directory file descriptors. After completing the final, FTS_DP, visit of a directory, RESTORE_INITIAL_CWD intended to clear the FD cache, but then proceeded to add a new FD to it via the subsequent FCHDIR (which calls cwd_advance_fd and i_ring_push). Before, the final file descriptor would be closed only via fts_close's call to fd_ring_clear. Now, it is usually closed earlier, via the final FTS_DP-returning fts_read call. * lib/fts.c (restore_initial_cwd): New function, converted from the macro. Call fd_ring_clear *after* FCHDIR, not before it. Update callers. Reported by Franz Sirl via the above URL, with analysis by Eric Blake in http://thread.gmane.org/gmane.comp.lib.gnulib.bugs/28739
author Jim Meyering <meyering@redhat.com>
date Sun, 23 Oct 2011 22:42:25 +0200
parents 716e67b8d5a9
children 8250f2777afc
line wrap: on
line source

/* Open a stream to a file.
   Copyright (C) 2007-2011 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>, 2007.  */

/* If the user's config.h happens to include <stdio.h>, let it include only
   the system's <stdio.h> here, so that orig_freopen doesn't recurse to
   rpl_freopen.  */
#define __need_FILE
#include <config.h>

/* Get the original definition of freopen.  It might be defined as a macro.  */
#include <stdio.h>
#undef __need_FILE

static inline FILE *
orig_freopen (const char *filename, const char *mode, FILE *stream)
{
  return freopen (filename, mode, stream);
}

/* Specification.  */
/* Write "stdio.h" here, not <stdio.h>, otherwise OSF/1 5.1 DTK cc eliminates
   this include because of the preliminary #include <stdio.h> above.  */
#include "stdio.h"

#include <string.h>

FILE *
rpl_freopen (const char *filename, const char *mode, FILE *stream)
{
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
  if (filename != NULL && strcmp (filename, "/dev/null") == 0)
    filename = "NUL";
#endif

  return orig_freopen (filename, mode, stream);
}