elf/dl-object.c

   1 /* Storage management for the chain of loaded shared objects.
   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 <errno.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23 #include <unistd.h>
  24 #include <elf/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;
  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 necesary 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   /* This is our local scope.  */
  71   if (loader != NULL)
  72     {
  73       while (loader->l_loader != NULL)
  74         loader = loader->l_loader;
  75       new->l_scope[idx] = &loader->l_searchlist;
  76     }
  77   else
  78     new->l_scope[idx] = &new->l_searchlist;
  79
  80   new->l_local_scope[0] = new->l_scope[idx];
  81
  82   /* Don't try to find the origin for the main map which has the name "".  */
  83   if (realname[0] != '\0')
  84     {
  85       char *origin;
  86
  87       if (realname[0] == '/')
  88         {
  89           /* It an absolute path.  Use it.  But we have to make a copy since
  90              we strip out the trailing slash.  */
  91           size_t len = strlen (realname) + 1;
  92           origin = malloc (len);
  93           if (origin == NULL)
  94             origin = (char *) -1;
  95           else
  96             memcpy (origin, realname, len);
  97         }
  98       else
  99         {
 100           size_t realname_len = strlen (realname) + 1;
 101           size_t len = 128 + realname_len;
 102           char *result = NULL;
 103
 104           /* Get the current directory name.  */
 105           origin = malloc (len);
 106
 107           while (origin != NULL
 108                  && (result = __getcwd (origin, len - realname_len)) == NULL
 109                  && errno == ERANGE)
 110             {
 111               len += 128;
 112               origin = (char *) realloc (origin, len);
 113             }
 114
 115           if (result == NULL)
 116             {
 117               /* We were not able to determine the current directory.  */
 118               if (origin != NULL)
 119                 free (origin);
 120               origin = (char *) -1;
 121             }
 122           else
 123             {
 124               /* Now append the filename.  */
 125               char *cp = strchr (origin, '\0');
 126
 127               if (cp [-1] != '/')
 128                 *cp++ = '/';
 129
 130               memcpy (cp, realname, realname_len);
 131             }
 132         }
 133
 134       if (origin != (char *) -1)
 135         {
 136           /* Now remove the filename and the slash.  Do this even if the
 137              string is something like "/foo" which leaves an empty string.  */
 138           char *last = strrchr (origin, '/');
 139
 140           if (last == origin)
 141             origin[1] = '\0';
 142           else
 143             *last = '\0';
 144         }
 145
 146       new->l_origin = origin;
 147     }
 148
 149   return new;
 150 }