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/* Open a descriptor to a file.
Copyright (C) 2007-2008 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. */
#include <config.h>
/* Specification. */
#include <fcntl.h>
/* If the fchdir replacement is used, open() is defined in fchdir.c. */
#ifndef FCHDIR_REPLACEMENT
# include <errno.h>
# include <stdarg.h>
# include <string.h>
# include <sys/types.h>
# include <sys/stat.h>
int
open (const char *filename, int flags, ...)
# undef open
{
mode_t mode;
int fd;
mode = 0;
if (flags & O_CREAT)
{
va_list arg;
va_start (arg, flags);
/* If mode_t is narrower than int, use the promoted type (int),
not mode_t. Use sizeof to guess whether mode_t is narrower;
we don't know of any practical counterexamples. */
mode = (sizeof (mode_t) < sizeof (int)
? va_arg (arg, int)
: va_arg (arg, mode_t));
va_end (arg);
}
# if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
if (strcmp (filename, "/dev/null") == 0)
filename = "NUL";
# endif
# if OPEN_TRAILING_SLASH_BUG
/* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
is specified, then fail.
Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
says that
"A pathname that contains at least one non-slash character and that
ends with one or more trailing slashes shall be resolved as if a
single dot character ( '.' ) were appended to the pathname."
and
"The special filename dot shall refer to the directory specified by
its predecessor."
If the named file already exists as a directory, then
- if O_CREAT is specified, open() must fail because of the semantics
of O_CREAT,
- if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
<http://www.opengroup.org/susv3/functions/open.html> says that it
fails with errno = EISDIR in this case.
If the named file does not exist or does not name a directory, then
- if O_CREAT is specified, open() must fail since open() cannot create
directories,
- if O_WRONLY or O_RDWR is specified, open() must fail because the
file does not contain a '.' directory. */
if (flags & (O_CREAT | O_WRONLY | O_RDWR))
{
size_t len = strlen (filename);
if (len > 0 && filename[len - 1] == '/')
{
errno = EISDIR;
return -1;
}
}
# endif
fd = open (filename, flags, mode);
# if OPEN_TRAILING_SLASH_BUG
/* If the filename ends in a slash and fd does not refer to a directory,
then fail.
Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
says that
"A pathname that contains at least one non-slash character and that
ends with one or more trailing slashes shall be resolved as if a
single dot character ( '.' ) were appended to the pathname."
and
"The special filename dot shall refer to the directory specified by
its predecessor."
If the named file without the slash is not a directory, open() must fail
with ENOTDIR. */
if (fd >= 0)
{
size_t len = strlen (filename);
if (len > 0 && filename[len - 1] == '/')
{
struct stat statbuf;
if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
{
close (fd);
errno = ENOTDIR;
return -1;
}
}
}
# endif
return fd;
}
#endif
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