1 | /* areadlink.c -- readlink wrapper to return the link name in malloc'd storage |
2 | Unlike xreadlink and xreadlink_with_size, don't ever call exit. |
3 | |
4 | Copyright (C) 2001, 2003-2007, 2009-2019 Free Software Foundation, Inc. |
5 | |
6 | This program is free software: you can redistribute it and/or modify |
7 | it under the terms of the GNU General Public License as published by |
8 | the Free Software Foundation; either version 3 of the License, or |
9 | (at your option) any later version. |
10 | |
11 | This program is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
14 | GNU General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU General Public License |
17 | along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
18 | |
19 | /* Written by Jim Meyering <jim@meyering.net> |
20 | and Bruno Haible <bruno@clisp.org>. */ |
21 | |
22 | #include <config.h> |
23 | |
24 | /* Specification. */ |
25 | #include "areadlink.h" |
26 | |
27 | #include "careadlinkat.h" |
28 | |
29 | #include <stdlib.h> |
30 | #include <unistd.h> |
31 | |
32 | /* Get the symbolic link value of FILENAME and put it into BUFFER, with |
33 | size BUFFER_SIZE. This function acts like readlink but has |
34 | readlinkat's signature. */ |
35 | static ssize_t |
36 | careadlinkatcwd (int fd, char const *filename, char *buffer, |
37 | size_t buffer_size) |
38 | { |
39 | /* FD must be AT_FDCWD here, otherwise the caller is using this |
40 | function in contexts it was not meant for. */ |
41 | if (fd != AT_FDCWD) |
42 | abort (); |
43 | return readlink (filename, buffer, buffer_size); |
44 | } |
45 | |
46 | /* Call readlink to get the symbolic link value of FILENAME. |
47 | Return a pointer to that NUL-terminated string in malloc'd storage. |
48 | If readlink fails, return NULL and set errno. |
49 | If allocation fails, or if the link value is longer than SIZE_MAX :-), |
50 | return NULL and set errno to ENOMEM. */ |
51 | |
52 | char * |
53 | areadlink (char const *filename) |
54 | { |
55 | return careadlinkat (AT_FDCWD, filename, NULL, 0, NULL, careadlinkatcwd); |
56 | } |
57 | |