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       size_t len_objname = strlen (objname) + 1;
  80       size_t len_errstring = strlen (errstring) + 1;
  81
  82       lcatch->errstring = (char *) malloc (len_objname + len_errstring);
  83       if (lcatch->errstring != NULL)
  84         /* Make a copy of the object file name and the error string.  */
  85         lcatch->objname = memcpy (__mempcpy ((char *) lcatch->errstring,
  86                                              errstring, len_errstring),
  87                                   objname, len_objname);
  88       else
  89         {
  90           /* This is better than nothing.  */
  91           lcatch->objname = "";
  92           lcatch->errstring = _dl_out_of_memory;
  93         }
  94       longjmp (lcatch->env, errcode ?: -1);
  95     }
  96   else
  97     {
  98       /* Lossage while resolving the program's own symbols is always fatal.  */
  99       char buffer[1024];
 100       _dl_sysdep_fatal (_dl_argv[0] ?: "<program name unknown>",
 101                         ": error while loading shared libraries: ",
 102                         objname ?: "", objname && *objname ? ": " : "",
 103                         errstring, errcode ? ": " : "",
 104                         (errcode
 105                          ? __strerror_r (errcode, buffer, sizeof buffer)
 106                          : ""), "\n", NULL);
 107     }
 108 }
 109
 110
 111 void
 112 internal_function
 113 _dl_signal_cerror (int errcode,
 114                    const char *objname,
 115                    const char *errstring)
 116 {
 117   if (receiver)
 118     {
 119       /* We are inside _dl_receive_error.  Call the user supplied
 120          handler and resume the work.  The receiver will still be
 121          installed.  */
 122       (*receiver) (errcode, objname, errstring);
 123     }
 124   else
 125     _dl_signal_error (errcode, objname, errstring);
 126 }
 127
 128
 129 int
 130 internal_function
 131 _dl_catch_error (const char **objname, const char **errstring,
 132                  void (*operate) (void *), void *args)
 133 {
 134   int errcode;
 135   struct catch *volatile old;
 136   struct catch c;
 137   /* We need not handle `receiver' since setting a `catch' is handled
 138      before it.  */
 139
 140   /* Some systems (e.g., SPARC) handle constructors to local variables
 141      inefficient.  So we initialize `c' by hand.  */
 142   c.errstring = NULL;
 143
 144   old = tsd_getspecific ();
 145   errcode = setjmp (c.env);
 146   if (errcode == 0)
 147     {
 148       tsd_setspecific (&c);
 149       (*operate) (args);
 150       tsd_setspecific (old);
 151       *objname = NULL;
 152       *errstring = NULL;
 153       return 0;
 154     }
 155
 156   /* We get here only if we longjmp'd out of OPERATE.  */
 157   tsd_setspecific (old);
 158   *objname = c.objname;
 159   *errstring = c.errstring;
 160   return errcode == -1 ? 0 : errcode;
 161 }
 162
 163 void
 164 internal_function
 165 _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
 166 {
 167   struct catch *old_catch;
 168   receiver_fct old_receiver;
 169
 170   old_catch = tsd_getspecific ();
 171   old_receiver = receiver;
 172
 173   /* Set the new values.  */
 174   tsd_setspecific (NULL);
 175   receiver = fct;
 176
 177   (*operate) (args);
 178
 179   tsd_setspecific (old_catch);
 180   receiver = old_receiver;
 181 }