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 is the internal function we use to generate the error string.  */
  27 extern char *_strerror_internal __P ((int, char *, size_t));
  28
  29 /* This structure communicates state between _dl_catch_error and
  30    _dl_signal_error.  */
  31 struct catch
  32   {
  33     char *errstring;            /* Error detail filled in here.  */
  34     const char *objname;
  35     jmp_buf env;                /* longjmp here on error.  */
  36   };
  37
  38 /* This points to such a structure during a call to _dl_catch_error.
  39    During implicit startup and run-time work for needed shared libraries,
  40    this is null.  */
  41 static struct catch *catch;
  42
  43 /* This points to a function which is called when an error is
  44    received.  Unlike the handling of `catch' this function may return.
  45    The arguments will be the `errstring' and `objname'.  */
  46 static receiver_fct receiver;
  47
  48
  49 void
  50 _dl_signal_error (int errcode,
  51                   const char *objname,
  52                   const char *errstring)
  53 {
  54   if (! errstring)
  55     errstring = "DYNAMIC LINKER BUG!!!";
  56
  57   if (catch)
  58     {
  59       /* We are inside _dl_catch_error.  Return to it.  We have to
  60          duplicate the error string since it might be allocated on the
  61          stack.  */
  62       size_t len = strlen (errstring) + 1;
  63       catch->errstring = malloc (len);
  64       if (catch->errstring != NULL)
  65         memcpy (catch->errstring, errstring, len);
  66       catch->objname = objname;
  67       longjmp (catch->env, errcode ?: -1);
  68     }
  69   else if (receiver)
  70     {
  71       /* We are inside _dl_receive_error.  Call the user supplied
  72          handler and resume the work.  The receiver will still be
  73          installed.  */
  74       (*receiver) (errcode, objname, errstring);
  75     }
  76   else
  77     {
  78       /* Lossage while resolving the program's own symbols is always fatal.  */
  79       extern char **_dl_argv;   /* Set in rtld.c at startup.  */
  80       char buffer[1024];
  81       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
  82                         ": error in loading shared libraries: ",
  83                         objname ?: "", objname && *objname ? ": " : "",
  84                         errstring, errcode ? ": " : "",
  85                         (errcode
  86                          ? _strerror_internal (errcode, buffer, sizeof buffer)
  87                          : ""), "\n", NULL);
  88     }
  89 }
  90
  91 int
  92 _dl_catch_error (char **errstring,
  93                  const char **objname,
  94                  void (*operate) (void *),
  95                  void *args)
  96 {
  97   int errcode;
  98   struct catch *old, c;
  99   /* We need not handle `receiver' since setting a `catch' is handled
 100      before it.  */
 101
 102   /* Some systems (e.g., SPARC) handle constructors to local variables
 103      inefficient.  So we initialize `c' by hand.  */
 104   c.errstring = NULL;
 105   c.objname   = NULL;
 106
 107   old = catch;
 108   errcode = setjmp (c.env);
 109   if (errcode == 0)
 110     {
 111       catch = &c;
 112       (*operate) (args);
 113       catch = old;
 114       *errstring = NULL;
 115       *objname = NULL;
 116       return 0;
 117     }
 118
 119   /* We get here only if we longjmp'd out of OPERATE.  */
 120   catch = old;
 121   *errstring = c.errstring;
 122   *objname = c.objname;
 123   return errcode == -1 ? 0 : errcode;
 124 }
 125
 126 void
 127 _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
 128 {
 129   struct catch *old_catch;
 130   receiver_fct old_receiver;
 131
 132   old_catch = catch;
 133   old_receiver = receiver;
 134
 135   /* Set the new values.  */
 136   catch = NULL;
 137   receiver = fct;
 138
 139   (*operate) (args);
 140
 141   catch = old_catch;
 142   receiver = old_receiver;
 143 }