1 /* areadlinkat.c -- readlinkat wrapper to return malloc'd link name 2 Unlike xreadlinkat, only call exit on failure to change directory. 3 4 Copyright (C) 2001, 2003-2007, 2009-2021 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 and Eric Blake <ebb9@byu.net>. */ 22 23 #include <config.h> 24 25 /* Specification. */ 26 #include "areadlink.h" 27 28 #include <stdlib.h> 29 30 #include "careadlinkat.h" 31 32 #if HAVE_READLINKAT 33 34 /* Call readlinkat to get the symbolic link value of FILENAME relative to FD. 35 Return a pointer to that NUL-terminated string in malloc'd storage. 36 If readlinkat fails, return NULL and set errno (although failure to 37 change directory will issue a diagnostic and exit). 38 If allocation fails, or if the link value is longer than SIZE_MAX :-), 39 return NULL and set errno to ENOMEM. */ 40 41 char * 42 areadlinkat (int fd, char const *filename) /* */ 43 { 44 return careadlinkat (fd, filename, NULL, 0, NULL, readlinkat); 45 } 46 47 #else /* !HAVE_READLINKAT */ 48 49 /* It is more efficient to change directories only once and call 50 areadlink, rather than repeatedly call the replacement 51 readlinkat. */ 52 53 # define AT_FUNC_NAME areadlinkat 54 # define AT_FUNC_F1 areadlink 55 # define AT_FUNC_POST_FILE_PARAM_DECLS /* empty */ 56 # define AT_FUNC_POST_FILE_ARGS /* empty */ 57 # define AT_FUNC_RESULT char * 58 # define AT_FUNC_FAIL NULL 59 # include "at-func.c" 60 # undef AT_FUNC_NAME 61 # undef AT_FUNC_F1 62 # undef AT_FUNC_POST_FILE_PARAM_DECLS 63 # undef AT_FUNC_POST_FILE_ARGS 64 # undef AT_FUNC_RESULT 65 # undef AT_FUNC_FAIL 66 67 #endif /* !HAVE_READLINKAT */