elf/dl-object.c

   1 /* Storage management for the chain of loaded shared objects.
   2    Copyright (C) 1995-2002, 2004 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 <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, int mode, Lmid_t nsid)
  36 {
  37   struct link_map *l;
  38   int idx;
  39   size_t libname_len = strlen (libname) + 1;
  40   struct link_map *new;
  41   struct libname_list *newname;
  42
  43   new = (struct link_map *) calloc (sizeof (*new) + sizeof (*newname)
  44                                     + libname_len, 1);
  45   if (new == NULL)
  46     return NULL;
  47
  48   new->l_real = new;
  49   new->l_libname = newname = (struct libname_list *) (new + 1);
  50   newname->name = (char *) memcpy (newname + 1, libname, libname_len);
  51   /* newname->next = NULL;      We use calloc therefore not necessary.  */
  52   newname->dont_free = 1;
  53
  54   new->l_name = realname;
  55   new->l_type = type;
  56   new->l_loader = loader;
  57 #if defined USE_TLS && NO_TLS_OFFSET != 0
  58   new->l_tls_offset = NO_TLS_OFFSET;
  59 #endif
  60   new->l_ns = nsid;
  61
  62   /* new->l_global = 0; We use calloc therefore not necessary.  */
  63
  64   /* Use the 'l_scope_mem' array by default for the the 'l_scope'
  65      information.  If we need more entries we will allocate a large
  66      array dynamically.  */
  67   new->l_scope = new->l_scope_mem;
  68   new->l_scope_max = sizeof (new->l_scope_mem) / sizeof (new->l_scope_mem[0]);
  69
  70   /* Counter for the scopes we have to handle.  */
  71   idx = 0;
  72
  73   if (GL(dl_ns)[nsid]._ns_loaded != NULL)
  74     {
  75       l = GL(dl_ns)[nsid]._ns_loaded;
  76       while (l->l_next != NULL)
  77         l = l->l_next;
  78       new->l_prev = l;
  79       /* new->l_next = NULL;    Would be necessary but we use calloc.  */
  80       l->l_next = new;
  81
  82       /* Add the global scope.  */
  83       new->l_scope[idx++] = &GL(dl_ns)[nsid]._ns_loaded->l_searchlist;
  84     }
  85   else
  86     GL(dl_ns)[nsid]._ns_loaded = new;
  87   ++GL(dl_ns)[nsid]._ns_nloaded;
  88   ++GL(dl_load_adds);
  89
  90   /* If we have no loader the new object acts as it.  */
  91   if (loader == NULL)
  92     loader = new;
  93   else
  94     /* Determine the local scope.  */
  95     while (loader->l_loader != NULL)
  96       loader = loader->l_loader;
  97
  98   /* Insert the scope if it isn't the global scope we already added.  */
  99   if (idx == 0 || &loader->l_searchlist != new->l_scope[0])
 100     {
 101       if ((mode & RTLD_DEEPBIND) != 0 && idx != 0)
 102         {
 103           new->l_scope[1] = new->l_scope[0];
 104           idx = 0;
 105         }
 106
 107       new->l_scope[idx] = &loader->l_searchlist;
 108     }
 109
 110   new->l_local_scope[0] = &new->l_searchlist;
 111
 112   /* Don't try to find the origin for the main map which has the name "".  */
 113   if (realname[0] != '\0')
 114     {
 115       size_t realname_len = strlen (realname) + 1;
 116       char *origin;
 117       char *cp;
 118
 119       if (realname[0] == '/')
 120         {
 121           /* It is an absolute path.  Use it.  But we have to make a
 122              copy since we strip out the trailing slash.  */
 123           cp = origin = (char *) malloc (realname_len);
 124           if (origin == NULL)
 125             {
 126               origin = (char *) -1;
 127               goto out;
 128             }
 129         }
 130       else
 131         {
 132           size_t len = realname_len;
 133           char *result = NULL;
 134
 135           /* Get the current directory name.  */
 136           origin = NULL;
 137           do
 138             {
 139               char *new_origin;
 140
 141               len += 128;
 142               new_origin = (char *) realloc (origin, len);
 143               if (new_origin == NULL)
 144                 /* We exit the loop.  Note that result == NULL.  */
 145                 break;
 146               origin = new_origin;
 147             }
 148           while ((result = __getcwd (origin, len - realname_len)) == NULL
 149                  && errno == ERANGE);
 150
 151           if (result == NULL)
 152             {
 153               /* We were not able to determine the current directory.
 154                  Note that free(origin) is OK if origin == NULL.  */
 155               free (origin);
 156               origin = (char *) -1;
 157               goto out;
 158             }
 159
 160           /* Find the end of the path and see whether we have to add a
 161              slash.  We could use rawmemchr but this need not be
 162              fast.  */
 163           cp = (strchr) (origin, '\0');
 164           if (cp[-1] != '/')
 165             *cp++ = '/';
 166         }
 167
 168       /* Add the real file name.  */
 169       cp = __mempcpy (cp, realname, realname_len);
 170
 171       /* Now remove the filename and the slash.  Leave the slash if
 172          the name is something like "/foo".  */
 173       do
 174         --cp;
 175       while (*cp != '/');
 176
 177       if (cp == origin)
 178         /* Keep the only slash which is the first character.  */
 179         ++cp;
 180       *cp = '\0';
 181
 182     out:
 183       new->l_origin = origin;
 184     }
 185
 186   return new;
 187 }