lib/xreadlinkat.c

   1 /* xreadlinkat.c -- readlink wrapper to return the link name in malloc'd storage
   2
   3    Copyright (C) 2001, 2003-2007, 2009-2024 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 <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Jim Meyering <jim@meyering.net>,
  19    and Bruno Haible <bruno@clisp.org>,
  20    and Eric Blake <ebb9@byu.net>.  */
  21
  22 #include <config.h>
  23
  24 /* Specification.  */
  25 #include "xreadlink.h"
  26
  27 #include <errno.h>
  28
  29 #include "areadlink.h"
  30 #include "xalloc.h"
  31
  32 /* Call readlinkat to get the symbolic link value of FILENAME relative to FD.
  33    Return a pointer to that NUL-terminated string in malloc'd storage.
  34    If readlinkat fails, return NULL and set errno (although failure to
  35    change directory will issue a diagnostic and exit).
  36    If realloc fails, or if the link value is longer than SIZE_MAX :-),
  37    give a diagnostic and exit.  */
  38
  39 char *
  40 xreadlinkat (int fd, char const *filename)
  41 {
  42   char *result = areadlinkat (fd, filename);
  43   if (result == NULL && errno == ENOMEM)
  44     xalloc_die ();
  45   return result;
  46 }