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Diffstat (limited to 'lib/areadlink.c')
-rw-r--r-- | lib/areadlink.c | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/lib/areadlink.c b/lib/areadlink.c new file mode 100644 index 0000000..0bff4a9 --- /dev/null +++ b/lib/areadlink.c @@ -0,0 +1,56 @@ +/* areadlink.c -- readlink wrapper to return the link name in malloc'd storage + Unlike xreadlink and xreadlink_with_size, don't ever call exit. + + Copyright (C) 2001, 2003-2007, 2009-2022 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file 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 Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Jim Meyering <jim@meyering.net> + and Bruno Haible <bruno@clisp.org>. */ + +#include <config.h> + +/* Specification. */ +#include "areadlink.h" + +#include "careadlinkat.h" + +#include <stdlib.h> +#include <unistd.h> + +/* Get the symbolic link value of FILENAME and put it into BUFFER, with + size BUFFER_SIZE. This function acts like readlink but has + readlinkat's signature. */ +static ssize_t +careadlinkatcwd (int fd, char const *filename, char *buffer, + size_t buffer_size) +{ + /* FD must be AT_FDCWD here, otherwise the caller is using this + function in contexts it was not meant for. */ + if (fd != AT_FDCWD) + abort (); + return readlink (filename, buffer, buffer_size); +} + +/* Call readlink to get the symbolic link value of FILENAME. + Return a pointer to that NUL-terminated string in malloc'd storage. + If readlink fails, return NULL and set errno. + If allocation fails, or if the link value is longer than SIZE_MAX :-), + return NULL and set errno to ENOMEM. */ + +char * +areadlink (char const *filename) +{ + return careadlinkat (AT_FDCWD, filename, NULL, 0, NULL, careadlinkatcwd); +} |