gdb/common/mingw-strerror.c

   1 /* Safe version of strerror for MinGW, for GDB, the GNU debugger.
   2
   3    Copyright (C) 2006-2019 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
  22 #include <windows.h>
  23
  24 /* Implementation of safe_strerror as defined in common-utils.h.
  25
  26    The Windows runtime implementation of strerror never returns NULL,
  27    but does return a useless string for anything above sys_nerr;
  28    unfortunately this includes all socket-related error codes.
  29    This replacement tries to find a system-provided error message.  */
  30
  31 char *
  32 safe_strerror (int errnum)
  33 {
  34   static char *buffer;
  35   int len;
  36
  37   if (errnum >= 0 && errnum < sys_nerr)
  38     return strerror (errnum);
  39
  40   if (buffer)
  41     {
  42       LocalFree (buffer);
  43       buffer = NULL;
  44     }
  45
  46   if (FormatMessage (FORMAT_MESSAGE_ALLOCATE_BUFFER
  47                      | FORMAT_MESSAGE_FROM_SYSTEM,
  48                      NULL, errnum,
  49                      MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT),
  50                      (LPTSTR) &buffer, 0, NULL) == 0)
  51     {
  52       static char buf[32];
  53       xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum);
  54       return buf;
  55     }
  56
  57   /* Windows error messages end with a period and a CR-LF; strip that
  58      out.  */
  59   len = strlen (buffer);
  60   if (len > 3 && strcmp (buffer + len - 3, ".\r\n") == 0)
  61     buffer[len - 3] = '\0';
  62
  63   return buffer;
  64 }