elf/dl-error.c

   1 /* Error handling for runtime dynamic linker.
   2    Copyright (C) 1995,96,97,98,99,2000,2001,2002 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    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 INTVARDEF(_dl_out_of_memory)
  53
  54
  55 /* This points to a function which is called when an continuable error is
  56    received.  Unlike the handling of `catch' this function may return.
  57    The arguments will be the `errstring' and `objname'.
  58
  59    Since this functionality is not used in normal programs (only in ld.so)
  60    we do not care about multi-threaded programs here.  We keep this as a
  61    global variable.  */
  62 static receiver_fct receiver;
  63
  64
  65 void
  66 internal_function
  67 _dl_signal_error (int errcode, const char *objname, const char *occation,
  68                   const char *errstring)
  69 {
  70   struct catch *lcatch;
  71
  72   if (! errstring)
  73     errstring = N_("DYNAMIC LINKER BUG!!!");
  74
  75   lcatch = tsd_getspecific ();
  76   if (objname == NULL)
  77     objname = "";
  78   if (lcatch != NULL)
  79     {
  80       /* We are inside _dl_catch_error.  Return to it.  We have to
  81          duplicate the error string since it might be allocated on the
  82          stack.  The object name is always a string constant.  */
  83       size_t len_objname = strlen (objname) + 1;
  84       size_t len_errstring = strlen (errstring) + 1;
  85
  86       lcatch->errstring = (char *) malloc (len_objname + len_errstring);
  87       if (lcatch->errstring != NULL)
  88         /* Make a copy of the object file name and the error string.  */
  89         lcatch->objname = memcpy (__mempcpy ((char *) lcatch->errstring,
  90                                              errstring, len_errstring),
  91                                   objname, len_objname);
  92       else
  93         {
  94           /* This is better than nothing.  */
  95           lcatch->objname = "";
  96           lcatch->errstring = INTUSE(_dl_out_of_memory);
  97         }
  98       longjmp (lcatch->env, errcode ?: -1);
  99     }
 100   else
 101     {
 102       /* Lossage while resolving the program's own symbols is always fatal.  */
 103       char buffer[1024];
 104       _dl_fatal_printf ("%s: %s: %s%s%s%s%s\n",
 105                         rtld_progname ?: "<program name unknown>",
 106                         occation ?: N_("error while loading shared libraries"),
 107                         objname, *objname ? ": " : "",
 108                         errstring, errcode ? ": " : "",
 109                         (errcode
 110                          ? __strerror_r (errcode, buffer, sizeof buffer)
 111                          : ""));
 112     }
 113 }
 114 INTDEF (_dl_signal_error)
 115
 116
 117 void
 118 internal_function
 119 _dl_signal_cerror (int errcode, const char *objname, const char *occation,
 120                    const char *errstring)
 121 {
 122   if (__builtin_expect (GL(dl_debug_mask), 0))
 123     INTUSE(_dl_debug_printf) ("%s: error: %s: %s (%s)\n", objname, occation,
 124                               errstring, receiver ? "continued" : "fatal");
 125
 126   if (receiver)
 127     {
 128       /* We are inside _dl_receive_error.  Call the user supplied
 129          handler and resume the work.  The receiver will still be
 130          installed.  */
 131       (*receiver) (errcode, objname, errstring);
 132     }
 133   else
 134     INTUSE(_dl_signal_error) (errcode, objname, occation, errstring);
 135 }
 136
 137
 138 int
 139 internal_function
 140 _dl_catch_error (const char **objname, const char **errstring,
 141                  void (*operate) (void *), void *args)
 142 {
 143   int errcode;
 144   struct catch *volatile old;
 145   struct catch c;
 146   /* We need not handle `receiver' since setting a `catch' is handled
 147      before it.  */
 148
 149   /* Some systems (e.g., SPARC) handle constructors to local variables
 150      inefficient.  So we initialize `c' by hand.  */
 151   c.errstring = NULL;
 152
 153   old = tsd_getspecific ();
 154   errcode = setjmp (c.env);
 155   if (__builtin_expect (errcode, 0) == 0)
 156     {
 157       tsd_setspecific (&c);
 158       (*operate) (args);
 159       tsd_setspecific (old);
 160       *objname = NULL;
 161       *errstring = NULL;
 162       return 0;
 163     }
 164
 165   /* We get here only if we longjmp'd out of OPERATE.  */
 166   tsd_setspecific (old);
 167   *objname = c.objname;
 168   *errstring = c.errstring;
 169   return errcode == -1 ? 0 : errcode;
 170 }
 171 INTDEF (_dl_catch_error)
 172
 173
 174 void
 175 internal_function
 176 _dl_receive_error (receiver_fct fct, void (*operate) (void *), void *args)
 177 {
 178   struct catch *old_catch;
 179   receiver_fct old_receiver;
 180
 181   old_catch = tsd_getspecific ();
 182   old_receiver = receiver;
 183
 184   /* Set the new values.  */
 185   tsd_setspecific (NULL);
 186   receiver = fct;
 187
 188   (*operate) (args);
 189
 190   tsd_setspecific (old_catch);
 191   receiver = old_receiver;
 192 }