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author | Lorry Tar Creator <lorry-tar-importer@lorry> | 2016-04-22 04:38:07 +0000 |
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committer | Lorry Tar Creator <lorry-tar-importer@lorry> | 2016-04-22 04:38:07 +0000 |
commit | 28ef1abc10cfbc2c3d2747c008eb2300858d0426 (patch) | |
tree | 41208fb8f393e6cb6cc8f939623ad47a0db17876 /lib/fd-safer.c | |
download | grep-tarball-28ef1abc10cfbc2c3d2747c008eb2300858d0426.tar.gz |
Diffstat (limited to 'lib/fd-safer.c')
-rw-r--r-- | lib/fd-safer.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/lib/fd-safer.c b/lib/fd-safer.c new file mode 100644 index 0000000..8a6bee2 --- /dev/null +++ b/lib/fd-safer.c @@ -0,0 +1,49 @@ +/* Return a safer copy of a file descriptor. + + Copyright (C) 2005-2006, 2009-2016 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 Paul Eggert. */ + +#include <config.h> + +#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. 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 (open ("file", O_RDONLY)). */ + +int +fd_safer (int fd) +{ + if (STDIN_FILENO <= fd && fd <= STDERR_FILENO) + { + int f = dup_safer (fd); + int e = errno; + close (fd); + errno = e; + fd = f; + } + + return fd; +} |