view lib/binary-io.h @ 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 f6ec6d171e52
children 8250f2777afc
line wrap: on
line source

/* Binary mode I/O.
   Copyright (C) 2001, 2003, 2005, 2008-2011 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/>.  */

#ifndef _BINARY_H
#define _BINARY_H

/* For systems that distinguish between text and binary I/O.
   O_BINARY is guaranteed by the gnulib <fcntl.h>. */
#include <fcntl.h>

/* The MSVC7 <stdio.h> doesn't like to be included after '#define fileno ...',
   so we include it here first.  */
#include <stdio.h>

/* SET_BINARY (fd);
   changes the file descriptor fd to perform binary I/O.  */
#if O_BINARY
# if defined __EMX__ || defined __DJGPP__ || defined __CYGWIN__
#  include <io.h> /* declares setmode() */
# else
#  define setmode _setmode
#  undef fileno
#  define fileno _fileno
# endif
# ifdef __DJGPP__
#  include <unistd.h> /* declares isatty() */
   /* Avoid putting stdin/stdout in binary mode if it is connected to
      the console, because that would make it impossible for the user
      to interrupt the program through Ctrl-C or Ctrl-Break.  */
#  define SET_BINARY(fd) ((void) (!isatty (fd) ? (setmode (fd, O_BINARY), 0) : 0))
# else
#  define SET_BINARY(fd) ((void) setmode (fd, O_BINARY))
# endif
#else
  /* On reasonable systems, binary I/O is the default.  */
# define SET_BINARY(fd) /* do nothing */ ((void) 0)
#endif

#endif /* _BINARY_H */