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 /* This points to a function which is called when an error is
  41    received.  Unlike the handling of `catch' this function may return.
  42    The arguments will be the `errstring' and `objname'.  */
  43 static receiver_fct receiver;
  44
  45
  46 void
  47 _dl_signal_error (int errcode,
  48                   const char *objname,
  49                   const char *errstring)
  50 {
  51   if (! errstring)
  52     errstring = "DYNAMIC LINKER BUG!!!";
  53
  54   if (catch)
  55     {
  56       /* We are inside _dl_catch_error.  Return to it.  We have to
  57          duplicate the error string since it might be allocated on the
  58          stack.  */
  59       size_t len = strlen (errstring) + 1;
  60       catch->errstring = malloc (len);
  61       if (catch->errstring != NULL)
  62         memcpy (catch->errstring, errstring, len);
  63       catch->objname = objname;
  64       longjmp (catch->env, errcode ?: -1);
  65     }
  66   else if (receiver)
  67     {
  68       /* We are inside _dl_receive_error.  Call the user supplied
  69          handler and resume the work.  The receiver will still be
  70          installed.  */
  71       (*receiver) (errcode, objname, errstring);
  72     }
  73   else
  74     {
  75       /* Lossage while resolving the program's own symbols is always fatal.  */
  76       extern char **_dl_argv;   /* Set in rtld.c at startup.  */
  77       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
  78                         ": error in loading shared libraries\n",
  79                         objname ?: "", objname ? ": " : "",
  80                         errstring, errcode ? ": " : "",
  81                         errcode ? strerror (errcode) : "", "\n", NULL);
  82     }
  83 }
  84
  85 int
  86 _dl_catch_error (char **errstring,
  87                  const char **objname,
  88                  void (*operate) (void))
  89 {
  90   int errcode;
  91   struct catch *old, c = { errstring: NULL, objname: NULL };
  92   /* We need not handle `receiver' since setting a `catch' is handle
  93      before it.  */
  94
  95   old = catch;
  96   errcode = setjmp (c.env);
  97   if (errcode == 0)
  98     {
  99       catch = &c;
 100       (*operate) ();
 101       catch = old;
 102       *errstring = NULL;
 103       *objname = NULL;
 104       return 0;
 105     }
 106
 107   /* We get here only if we longjmp'd out of OPERATE.  */
 108   catch = old;
 109   *errstring = c.errstring;
 110   *objname = c.objname;
 111   return errcode == -1 ? 0 : errcode;
 112 }
 113
 114 void
 115 _dl_receive_error (receiver_fct fct, void (*operate) (void))
 116 {
 117   struct catch *old_catch;
 118   receiver_fct old_receiver;
 119
 120   old_catch = catch;
 121   old_receiver = receiver;
 122
 123   /* Set the new values.  */
 124   catch = NULL;
 125   receiver = fct;
 126
 127   (*operate) ();
 128
 129   catch = old_catch;
 130   receiver = old_receiver;
 131 }