elf/dlerror.c

   1 /* Return error detail for failing <dlfcn.h> functions.
   2    Copyright (C) 1995, 1996, 1997 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 static const char *last_object_name;
  29
  30 char *
  31 dlerror (void)
  32 {
  33   static char *buf;
  34   char *ret;
  35
  36   if (buf)
  37     {
  38       free (buf);
  39       buf = NULL;
  40     }
  41
  42   if (! last_errstring)
  43     return NULL;
  44
  45   if (last_errcode == 0 && ! last_object_name)
  46     ret = (char *) last_errstring;
  47   else if (last_errcode == 0)
  48     ret = (asprintf (&buf, "%s: %s", last_object_name, last_errstring) == -1
  49            ? NULL : buf);
  50   else if (! last_object_name)
  51     ret = (asprintf (&buf, "%s: %s",
  52                      last_errstring, strerror (last_errcode)) == -1
  53            ? NULL : buf);
  54   else
  55     ret = (asprintf (&buf, "%s: %s: %s",
  56                      last_object_name, last_errstring,
  57                      strerror (last_errcode)) == -1
  58            ? NULL : buf);
  59
  60   /* Reset the error indicator.  */
  61   free (last_errstring);
  62   last_errstring = NULL;
  63   return ret;
  64 }
  65
  66 int
  67 _dlerror_run (void (*operate) (void))
  68 {
  69   if (last_errstring != NULL)
  70     /* Free the error string from the last failed command.  This can
  71        happen if `dlerror' was not run after an error was found.  */
  72     free (last_errstring);
  73
  74   last_errcode = _dl_catch_error (&last_errstring, &last_object_name,
  75                                   operate);
  76   return last_errstring != NULL;
  77 }