52 lines
1.7 KiB
C
52 lines
1.7 KiB
C
/* Adjust a file descriptor result so that it avoids clobbering
|
|
STD{IN,OUT,ERR}_FILENO, with specific flags.
|
|
|
|
Copyright (C) 2005-2006, 2009-2022 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 <https://www.gnu.org/licenses/>. */
|
|
|
|
/* Written by Paul Eggert and Eric Blake. */
|
|
|
|
#include <config.h>
|
|
|
|
/* Specification. */
|
|
#include "unistd-safer.h"
|
|
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
|
|
/* Return FD, unless FD would be a copy of standard input, output, or
|
|
error; in that case, return a duplicate of FD, closing FD. If FLAG
|
|
contains O_CLOEXEC, the returned FD will have close-on-exec
|
|
semantics. On failure to duplicate, close FD, set errno, and
|
|
return -1. Preserve errno if FD is negative, so that the caller
|
|
can always inspect errno when the returned value is negative.
|
|
|
|
This function is usefully wrapped around functions that return file
|
|
descriptors, e.g., fd_safer_flag (open ("file", O_RDONLY | flag), flag). */
|
|
|
|
int
|
|
fd_safer_flag (int fd, int flag)
|
|
{
|
|
if (STDIN_FILENO <= fd && fd <= STDERR_FILENO)
|
|
{
|
|
int f = dup_safer_flag (fd, flag);
|
|
int e = errno;
|
|
close (fd);
|
|
errno = e;
|
|
fd = f;
|
|
}
|
|
|
|
return fd;
|
|
}
|