string/strerror_l.c

   1 /* Copyright (C) 2007-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <libintl.h>
  19 #include <locale.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/param.h>
  24
  25
  26 static __thread char *last_value;
  27
  28
  29 static const char *
  30 translate (const char *str, locale_t loc)
  31 {
  32   locale_t oldloc = __uselocale (loc);
  33   const char *res = _(str);
  34   __uselocale (oldloc);
  35   return res;
  36 }
  37
  38
  39 /* Return a string describing the errno code in ERRNUM.  */
  40 char *
  41 strerror_l (int errnum, locale_t loc)
  42 {
  43
  44
  45   if (__builtin_expect (errnum < 0 || errnum >= _sys_nerr_internal
  46                         || _sys_errlist_internal[errnum] == NULL, 0))
  47     {
  48       free (last_value);
  49       if (__asprintf (&last_value, "%s%d",
  50                       translate ("Unknown error ", loc), errnum) == -1)
  51         last_value = NULL;
  52
  53       return last_value;
  54     }
  55
  56   return (char *) translate (_sys_errlist_internal[errnum], loc);
  57 }
  58
  59
  60 #ifdef _LIBC
  61 # ifdef _LIBC_REENTRANT
  62 /* This is called when a thread is exiting to free the last_value string.  */
  63 static void __attribute__ ((section ("__libc_thread_freeres_fn")))
  64 strerror_thread_freeres (void)
  65 {
  66   free (last_value);
  67 }
  68 text_set_element (__libc_thread_subfreeres, strerror_thread_freeres);
  69 text_set_element (__libc_subfreeres, strerror_thread_freeres);
  70 # endif
  71 #endif