elf/dl-error.c

   1 /* Error handling for runtime dynamic linker.
   2    Copyright (C) 1995, 1996, 1997, 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 <setjmp.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <unistd.h>
  24 #include <elf/ldsodefs.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     jmp_buf env;                /* longjmp here on error.  */
  32   };
  33
  34 /* This points to such a structure during a call to _dl_catch_error.
  35    During implicit startup and run-time work for needed shared libraries,
  36    this is null.  */
  37 static struct catch *catch;
  38
  39 /* This points to a function which is called when an error is
  40    received.  Unlike the handling of `catch' this function may return.
  41    The arguments will be the `errstring' and `objname'.  */
  42 static receiver_fct receiver;
  43
  44
  45 void
  46 internal_function
  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 objname_len = objname ? strlen (objname) + 2 : 0;
  60       size_t errstring_len = strlen (errstring) + 1;
  61       catch->errstring = malloc (objname_len + errstring_len);
  62       if (catch->errstring != NULL)
  63         {
  64           if (objname_len > 0)
  65             {
  66               memcpy (catch->errstring, objname, objname_len - 2);
  67               memcpy (catch->errstring + objname_len - 2, ": ", 2);
  68             }
  69           memcpy (catch->errstring + objname_len, errstring, errstring_len);
  70         }
  71       longjmp (catch->env, errcode ?: -1);
  72     }
  73   else if (receiver)
  74     {
  75       /* We are inside _dl_receive_error.  Call the user supplied
  76          handler and resume the work.  The receiver will still be
  77          installed.  */
  78       (*receiver) (errcode, objname, errstring);
  79     }
  80   else
  81     {
  82       /* Lossage while resolving the program's own symbols is always fatal.  */
  83       char buffer[1024];
  84       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
  85                         ": error in loading shared libraries: ",
  86                         objname ?: "", objname && *objname ? ": " : "",
  87                         errstring, errcode ? ": " : "",
  88                         (errcode
  89                          ? __strerror_r (errcode, buffer, sizeof buffer)
  90                          : ""), "\n", NULL);
  91     }
  92 }
  93
  94 int
  95 internal_function
  96 _dl_catch_error (char **errstring,
  97                  void (*operate) (void *),
  98                  void *args)
  99 {
 100   int errcode;
 101   struct catch *old, c;
 102   /* We need not handle `receiver' since setting a `catch' is handled
 103      before it.  */
 104
 105   /* Some systems (e.g., SPARC) handle constructors to local variables
 106      inefficient.  So we initialize `c' by hand.  */
 107   c.errstring = NULL;
 108
 109   old = catch;
 110   errcode = setjmp (c.env);
 111   if (errcode == 0)
 112     {
 113       catch = &c;
 114       (*operate) (args);
 115       catch = old;
 116       *errstring = NULL;
 117       return 0;
 118     }
 119
 120   /* We get here only if we longjmp'd out of OPERATE.  */
 121   catch = old;
 122   *errstring = c.errstring;
 123   return errcode == -1 ? 0 : errcode;
 124 }
 125
 126 void
 127 internal_function
 128 _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
 129 {
 130   struct catch *old_catch;
 131   receiver_fct old_receiver;
 132
 133   old_catch = catch;
 134   old_receiver = receiver;
 135
 136   /* Set the new values.  */
 137   catch = NULL;
 138   receiver = fct;
 139
 140   (*operate) (args);
 141
 142   catch = old_catch;
 143   receiver = old_receiver;
 144 }