| 1 | /* Read symbolic links into a buffer without size limitation, relative to fd. |
| 2 | |
| 3 | Copyright (C) 2011-2014 Free Software Foundation, Inc. |
| 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 |
| 21 | #define _GL_CAREADLINKAT_H |
| 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 | |
| 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. |
| 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 | |
| 55 | /* Suitable value for careadlinkat's FD argument. */ |
| 56 | #if HAVE_READLINKAT |
| 57 | /* AT_FDCWD is declared in <fcntl.h>. */ |
| 58 | #else |
| 59 | /* Define AT_FDCWD independently, so that the careadlinkat module does |
| 60 | not depend on the fcntl-h module. We might as well use the same value |
| 61 | as fcntl-h. */ |
| 62 | # ifndef AT_FDCWD |
| 63 | # define AT_FDCWD (-3041965) |
| 64 | # endif |
| 65 | #endif |
| 66 | |
| 67 | #endif /* _GL_CAREADLINKAT_H */ |