elf/dl-error.c

   1 /* Error handling for runtime dynamic linker.
   2    Copyright (C) 1995,96,97,98,99,2000 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 <libintl.h>
  21 #include <setjmp.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <ldsodefs.h>
  26 #include <bits/libc-tsd.h>
  27
  28 /* This structure communicates state between _dl_catch_error and
  29    _dl_signal_error.  */
  30 struct catch
  31   {
  32     const char *objname;        /* Object/File name.  */
  33     const char *errstring;      /* Error detail filled in here.  */
  34     jmp_buf env;                /* longjmp here on error.  */
  35   };
  36
  37 /* Multiple threads at once can use the `_dl_catch_error' function.  The
  38    calls can come from `_dl_map_object_deps', `_dlerror_run', or from
  39    any of the libc functionality which loads dynamic objects (NSS, iconv).
  40    Therefore we have to be prepared to save the state in thread-local
  41    memory.  */
  42
  43 __libc_tsd_define (static, DL_ERROR)
  44 #define tsd_getspecific()       __libc_tsd_get (DL_ERROR)
  45 #define tsd_setspecific(data)   __libc_tsd_set (DL_ERROR, (data))
  46
  47
  48 /* This message we return as a last resort.  We define the string in a
  49    variable since we have to avoid freeing it and so have to enable
  50    a pointer comparison.  See below and in dlfcn/dlerror.c.  */
  51 const char _dl_out_of_memory[] = "out of memory";
  52
  53
  54 /* This points to a function which is called when an continuable error is
  55    received.  Unlike the handling of `catch' this function may return.
  56    The arguments will be the `errstring' and `objname'.
  57
  58    Since this functionality is not used in normal programs (only in ld.so)
  59    we do not care about multi-threaded programs here.  We keep this as a
  60    global variable.  */
  61 static receiver_fct receiver;
  62
  63
  64 void
  65 internal_function
  66 _dl_signal_error (int errcode, const char *objname, const char *errstring)
  67 {
  68   struct catch *lcatch;
  69
  70   if (! errstring)
  71     errstring = N_("DYNAMIC LINKER BUG!!!");
  72
  73   lcatch = tsd_getspecific ();
  74   if (lcatch != NULL)
  75     {
  76       /* We are inside _dl_catch_error.  Return to it.  We have to
  77          duplicate the error string since it might be allocated on the
  78          stack.  The object name is always a string constant.  */
  79       lcatch->objname = objname;
  80       lcatch->errstring = strdup (errstring);
  81       if (lcatch->errstring == NULL)
  82         lcatch->errstring = _dl_out_of_memory;
  83       longjmp (lcatch->env, errcode ?: -1);
  84     }
  85   else
  86     {
  87       /* Lossage while resolving the program's own symbols is always fatal.  */
  88       char buffer[1024];
  89       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
  90                         ": error while loading shared libraries: ",
  91                         objname ?: "", objname && *objname ? ": " : "",
  92                         errstring, errcode ? ": " : "",
  93                         (errcode
  94                          ? __strerror_r (errcode, buffer, sizeof buffer)
  95                          : ""), "\n", NULL);
  96     }
  97 }
  98
  99
 100 void
 101 internal_function
 102 _dl_signal_cerror (int errcode,
 103                    const char *objname,
 104                    const char *errstring)
 105 {
 106   if (receiver)
 107     {
 108       /* We are inside _dl_receive_error.  Call the user supplied
 109          handler and resume the work.  The receiver will still be
 110          installed.  */
 111       (*receiver) (errcode, objname, errstring);
 112     }
 113   else
 114     _dl_signal_error (errcode, objname, errstring);
 115 }
 116
 117
 118 int
 119 internal_function
 120 _dl_catch_error (const char **objname, const char **errstring,
 121                  void (*operate) (void *), void *args)
 122 {
 123   int errcode;
 124   struct catch *volatile old;
 125   struct catch c;
 126   /* We need not handle `receiver' since setting a `catch' is handled
 127      before it.  */
 128
 129   /* Some systems (e.g., SPARC) handle constructors to local variables
 130      inefficient.  So we initialize `c' by hand.  */
 131   c.errstring = NULL;
 132
 133   old = tsd_getspecific ();
 134   errcode = setjmp (c.env);
 135   if (errcode == 0)
 136     {
 137       tsd_setspecific (&c);
 138       (*operate) (args);
 139       tsd_setspecific (old);
 140       *objname = NULL;
 141       *errstring = NULL;
 142       return 0;
 143     }
 144
 145   /* We get here only if we longjmp'd out of OPERATE.  */
 146   tsd_setspecific (old);
 147   *objname = c.objname;
 148   *errstring = c.errstring;
 149   return errcode == -1 ? 0 : errcode;
 150 }
 151
 152 void
 153 internal_function
 154 _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
 155 {
 156   struct catch *old_catch;
 157   receiver_fct old_receiver;
 158
 159   old_catch = tsd_getspecific ();
 160   old_receiver = receiver;
 161
 162   /* Set the new values.  */
 163   tsd_setspecific (NULL);
 164   receiver = fct;
 165
 166   (*operate) (args);
 167
 168   tsd_setspecific (old_catch);
 169   receiver = old_receiver;
 170 }