elf/dl-error.c

   1 /* Error handling for runtime dynamic linker.
   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 <stddef.h>
  21 #include <link.h>
  22 #include <setjmp.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 /* This structure communicates state between _dl_catch_error and
  27    _dl_signal_error.  */
  28 struct catch
  29   {
  30     char *errstring;            /* Error detail filled in here.  */
  31     const char *objname;
  32     jmp_buf env;                /* longjmp here on error.  */
  33   };
  34
  35 /* This points to such a structure during a call to _dl_catch_error.
  36    During implicit startup and run-time work for needed shared libraries,
  37    this is null.  */
  38 static struct catch *catch;
  39
  40
  41 void
  42 _dl_signal_error (int errcode,
  43                   const char *objname,
  44                   const char *errstring)
  45 {
  46   if (! errstring)
  47     errstring = "DYNAMIC LINKER BUG!!!";
  48
  49   if (catch)
  50     {
  51       /* We are inside _dl_catch_error.  Return to it.  We have to
  52          duplicate the error string since it might be allocated on the
  53          stack.  */
  54       size_t len = strlen (errstring) + 1;
  55       catch->errstring = malloc (len);
  56       if (catch->errstring != NULL)
  57         memcpy (catch->errstring, errstring, len);
  58       catch->objname = objname;
  59       longjmp (catch->env, errcode ?: -1);
  60     }
  61   else
  62     {
  63       /* Lossage while resolving the program's own symbols is always fatal.  */
  64       extern char **_dl_argv;   /* Set in rtld.c at startup.  */
  65       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
  66                         ": error in loading shared libraries\n",
  67                         objname ?: "", objname ? ": " : "",
  68                         errstring, errcode ? ": " : "",
  69                         errcode ? strerror (errcode) : "", "\n", NULL);
  70     }
  71 }
  72
  73 int
  74 _dl_catch_error (char **errstring,
  75                  const char **objname,
  76                  void (*operate) (void))
  77 {
  78   int errcode;
  79   struct catch *old, c = { errstring: NULL, objname: NULL };
  80
  81   old = catch;
  82   errcode = setjmp (c.env);
  83   if (errcode == 0)
  84     {
  85       catch = &c;
  86       (*operate) ();
  87       catch = old;
  88       *errstring = NULL;
  89       *objname = NULL;
  90       return 0;
  91     }
  92
  93   /* We get here only if we longjmp'd out of OPERATE.  */
  94   catch = old;
  95   *errstring = c.errstring;
  96   *objname = c.objname;
  97   return errcode == -1 ? 0 : errcode;
  98 }