elf/dlerror.c

   1 /* dlerror -- Return error detail for failing <dlfcn.h> functions.
   2    Copyright (C) 1995, 1996, 1998 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library 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 GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <link.h>
  21 #include <dlfcn.h>
  22 #include <stdio.h>
  23 #include <string.h>
  24 #include <stdlib.h>
  25
  26 static int last_errcode;
  27 static char *last_errstring;
  28
  29 char *
  30 dlerror (void)
  31 {
  32   static char *buf;
  33
  34   if (buf)
  35     {
  36       free (buf);
  37       buf = NULL;
  38     }
  39
  40   if (! last_errstring)
  41     return NULL;
  42
  43   if (last_errcode == 0)
  44     buf = last_errstring;
  45   else
  46     {
  47       if (asprintf (&buf, "%s: %s",
  48                     last_errstring, strerror (last_errcode)) == -1)
  49         buf = NULL;
  50
  51       /* We don't need the error string anymore.  */
  52       free (last_errstring);
  53     }
  54
  55   /* Reset the error indicator.  */
  56   last_errstring = NULL;
  57
  58   return buf;
  59 }
  60
  61 int
  62 _dlerror_run (void (*operate) (void))
  63 {
  64   if (last_errstring != NULL)
  65     /* Free the error string from the last failed command.  This can
  66        happen if `dlerror' was not run after an error was found.  */
  67     free (last_errstring);
  68
  69   last_errcode = _dl_catch_error (&last_errstring, operate);
  70   return last_errstring != NULL;
  71 }