+
−/* closexec.c - set or clear the close-on-exec descriptor flag
+
−
+
−   Copyright (C) 1991, 2004-2006, 2009-2013 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,
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−   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/>.
+
−
+
−   The code is taken from glibc/manual/llio.texi  */
+
−
+
−#include <config.h>
+
−
+
−#include "cloexec.h"
+
−
+
−#include <errno.h>
+
−#include <fcntl.h>
+
−#include <unistd.h>
+
−
+
−/* Set the 'FD_CLOEXEC' flag of DESC if VALUE is true,
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−   or clear the flag if VALUE is false.
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−   Return 0 on success, or -1 on error with 'errno' set.
+
−
+
−   Note that on MingW, this function does NOT protect DESC from being
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−   inherited into spawned children.  Instead, either use dup_cloexec
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−   followed by closing the original DESC, or use interfaces such as
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−   open or pipe2 that accept flags like O_CLOEXEC to create DESC
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−   non-inheritable in the first place.  */
+
−
+
−int
+
−set_cloexec_flag (int desc, bool value)
+
−{
+
−#ifdef F_SETFD
+
−
+
−  int flags = fcntl (desc, F_GETFD, 0);
+
−
+
−  if (0 <= flags)
+
−    {
+
−      int newflags = (value ? flags | FD_CLOEXEC : flags & ~FD_CLOEXEC);
+
−
+
−      if (flags == newflags
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−          || fcntl (desc, F_SETFD, newflags) != -1)
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−        return 0;
+
−    }
+
−
+
−  return -1;
+
−
+
−#else /* !F_SETFD */
+
−
+
−  /* Use dup2 to reject invalid file descriptors; the cloexec flag
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−     will be unaffected.  */
+
−  if (desc < 0)
+
−    {
+
−      errno = EBADF;
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−      return -1;
+
−    }
+
−  if (dup2 (desc, desc) < 0)
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−    /* errno is EBADF here.  */
+
−    return -1;
+
−
+
−  /* There is nothing we can do on this kind of platform.  Punt.  */
+
−  return 0;
+
−#endif /* !F_SETFD */
+
−}
+
−
+
−
+
−/* Duplicates a file handle FD, while marking the copy to be closed
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−   prior to exec or spawn.  Returns -1 and sets errno if FD could not
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−   be duplicated.  */
+
−
+
−int
+
−dup_cloexec (int fd)
+
−{
+
−  return fcntl (fd, F_DUPFD_CLOEXEC, 0);
+
−}