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1 | /* Read symbolic links into a buffer without size limitation, relative to fd. |
2 | ||
ba318903 | 3 | Copyright (C) 2011-2014 Free Software Foundation, Inc. |
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4 | |
5 | This program is free software: you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | /* Written by Paul Eggert, Bruno Haible, and Jim Meyering. */ | |
19 | ||
20 | #ifndef _GL_CAREADLINKAT_H | |
e5b28a7a | 21 | #define _GL_CAREADLINKAT_H |
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22 | |
23 | #include <fcntl.h> | |
24 | #include <unistd.h> | |
25 | ||
26 | struct allocator; | |
27 | ||
28 | /* Assuming the current directory is FD, get the symbolic link value | |
29 | of FILENAME as a null-terminated string and put it into a buffer. | |
30 | If FD is AT_FDCWD, FILENAME is interpreted relative to the current | |
31 | working directory, as in openat. | |
32 | ||
33 | If the link is small enough to fit into BUFFER put it there. | |
34 | BUFFER's size is BUFFER_SIZE, and BUFFER can be null | |
35 | if BUFFER_SIZE is zero. | |
36 | ||
37 | If the link is not small, put it into a dynamically allocated | |
38 | buffer managed by ALLOC. It is the caller's responsibility to free | |
39 | the returned value if it is nonnull and is not BUFFER. | |
40 | ||
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41 | The PREADLINKAT function specifies how to read links. It operates |
42 | like POSIX readlinkat() | |
43 | <http://pubs.opengroup.org/onlinepubs/9699919799/functions/readlink.html> | |
44 | but can assume that its first argument is the same as FD. | |
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45 | |
46 | If successful, return the buffer address; otherwise return NULL and | |
47 | set errno. */ | |
48 | ||
49 | char *careadlinkat (int fd, char const *filename, | |
50 | char *buffer, size_t buffer_size, | |
51 | struct allocator const *alloc, | |
52 | ssize_t (*preadlinkat) (int, char const *, | |
53 | char *, size_t)); | |
54 | ||
8376d87e | 55 | /* Suitable value for careadlinkat's FD argument. */ |
d1fdcab7 | 56 | #if HAVE_READLINKAT |
9afafefb | 57 | /* AT_FDCWD is declared in <fcntl.h>. */ |
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58 | #else |
59 | /* Define AT_FDCWD independently, so that the careadlinkat module does | |
8376d87e | 60 | not depend on the fcntl-h module. We might as well use the same value |
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61 | as fcntl-h. */ |
62 | # ifndef AT_FDCWD | |
63 | # define AT_FDCWD (-3041965) | |
64 | # endif | |
9afafefb | 65 | #endif |
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66 | |
67 | #endif /* _GL_CAREADLINKAT_H */ |