elf/dl-object.c

   1 /* Storage management for the chain of loaded shared objects.
   2    Copyright (C) 1995,96,97,98,99,2000,2001 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 <errno.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <ldsodefs.h>
  25
  26 #include <assert.h>
  27
  28
  29 /* Allocate a `struct link_map' for a new object being loaded,
  30    and enter it into the _dl_loaded list.  */
  31
  32 struct link_map *
  33 internal_function
  34 _dl_new_object (char *realname, const char *libname, int type,
  35                 struct link_map *loader)
  36 {
  37   struct link_map *l;
  38   int idx;
  39   size_t libname_len = strlen (libname) + 1;
  40   struct link_map *new = calloc (sizeof *new, 1);
  41   struct libname_list *newname = malloc (sizeof *newname + libname_len);
  42   if (! new || ! newname)
  43     return NULL;
  44
  45   new->l_name = realname;
  46   newname->name = memcpy (newname + 1, libname, libname_len);
  47   newname->next = NULL;
  48   new->l_libname = newname;
  49   new->l_type = type;
  50   new->l_loader = loader;
  51   /* new->l_global = 0; We use calloc therefore not necessary.  */
  52
  53   /* Counter for the scopes we have to handle.  */
  54   idx = 0;
  55
  56   if (_dl_loaded != NULL)
  57     {
  58       l = _dl_loaded;
  59       while (l->l_next)
  60         l = l->l_next;
  61       new->l_prev = l;
  62       /* new->l_next = NULL;    Would be necessary but we use calloc.  */
  63       l->l_next = new;
  64
  65       /* Add the global scope.  */
  66       new->l_scope[idx++] = &_dl_loaded->l_searchlist;
  67     }
  68   else
  69     _dl_loaded = new;
  70   ++_dl_nloaded;
  71   /* This is our local scope.  */
  72   if (loader != NULL)
  73     {
  74       while (loader->l_loader != NULL)
  75         loader = loader->l_loader;
  76       if (idx == 0 || &loader->l_searchlist != new->l_scope[0])
  77         new->l_scope[idx] = &loader->l_searchlist;
  78     }
  79   else if (idx == 0 || &new->l_searchlist != new->l_scope[0])
  80     new->l_scope[idx] = &new->l_searchlist;
  81
  82   new->l_local_scope[0] = &new->l_searchlist;
  83
  84   /* Don't try to find the origin for the main map which has the name "".  */
  85   if (realname[0] != '\0')
  86     {
  87       char *origin;
  88
  89       if (realname[0] == '/')
  90         {
  91           /* It an absolute path.  Use it.  But we have to make a copy since
  92              we strip out the trailing slash.  */
  93           size_t len = strlen (realname) + 1;
  94           origin = malloc (len);
  95           if (origin == NULL)
  96             origin = (char *) -1;
  97           else
  98             memcpy (origin, realname, len);
  99         }
 100       else
 101         {
 102           size_t realname_len = strlen (realname) + 1;
 103           size_t len = 128 + realname_len;
 104           char *result = NULL;
 105
 106           /* Get the current directory name.  */
 107           origin = malloc (len);
 108
 109           while (origin != NULL
 110                  && (result = __getcwd (origin, len - realname_len)) == NULL
 111                  && errno == ERANGE)
 112             {
 113               len += 128;
 114               origin = (char *) realloc (origin, len);
 115             }
 116
 117           if (result == NULL)
 118             {
 119               /* We were not able to determine the current directory.  */
 120               if (origin != NULL)
 121                 free (origin);
 122               origin = (char *) -1;
 123             }
 124           else
 125             {
 126               /* Now append the filename.  */
 127               char *cp = strchr (origin, '\0');
 128
 129               if (cp [-1] != '/')
 130                 *cp++ = '/';
 131
 132               memcpy (cp, realname, realname_len);
 133             }
 134         }
 135
 136       if (origin != (char *) -1)
 137         {
 138           /* Now remove the filename and the slash.  Do this even if the
 139              string is something like "/foo" which leaves an empty string.  */
 140           char *last = strrchr (origin, '/');
 141
 142           if (last == origin)
 143             origin[1] = '\0';
 144           else
 145             *last = '\0';
 146         }
 147
 148       new->l_origin = origin;
 149     }
 150
 151   return new;
 152 }