gdbsupport/safe-strerror.cc

   1 /* Safe version of strerror for GDB, the GNU debugger.
   2
   3    Copyright (C) 2006-2020 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "common-defs.h"
  21 #include <string.h>
  22
  23 /* There are two different versions of strerror_r; one is GNU-specific, the
  24    other XSI-compliant.  They differ in the return type.  This overload lets
  25    us choose the right behavior for each return type.  We cannot rely on Gnulib
  26    to solve this for us because IPA does not use Gnulib but uses this
  27    function.  */
  28
  29 /* Called if we have a XSI-compliant strerror_r.  */
  30 ATTRIBUTE_UNUSED static char *
  31 select_strerror_r (int res, char *buf)
  32 {
  33   return res == 0 ? buf : nullptr;
  34 }
  35
  36 /* Called if we have a GNU strerror_r.  */
  37 ATTRIBUTE_UNUSED static char *
  38 select_strerror_r (char *res, char *)
  39 {
  40   return res;
  41 }
  42
  43 /* Implementation of safe_strerror as defined in common-utils.h.  */
  44
  45 const char *
  46 safe_strerror (int errnum)
  47 {
  48   static thread_local char buf[1024];
  49
  50   char *res = select_strerror_r (strerror_r (errnum, buf, sizeof (buf)), buf);
  51   if (res != nullptr)
  52     return res;
  53
  54   xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
  55   return buf;
  56 }