1 files changed, 337 insertions, 0 deletions

diff --git a/elf/dl-version.c b/elf/dl-version.c
new file mode 100644
index 0000000..4382a4c
--- /dev/null
+++ b/elf/dl-version.c
@@ -0,0 +1,337 @@
+/* Handle symbol and library versioning.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Library General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Library General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with the GNU C Library; see the file COPYING.LIB.  If not,
+   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.  */
+
+#include <elf.h>
+#include <errno.h>
+#include <link.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "../stdio-common/_itoa.h"
+
+
+/* Set in rtld.c at startup.  */
+extern char **_dl_argv;
+
+#define VERSTAG(tag)	(DT_NUM + DT_PROCNUM + DT_VERSIONTAGIDX (tag))
+
+
+#define make_string(string, rest...) \
+  ({									      \
+    const char *all[] = { string, ## rest };				      \
+    size_t len, cnt;							      \
+    char *result, *cp;							      \
+									      \
+    len = 1;								      \
+    for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt)		      \
+      len += strlen (all[cnt]);						      \
+									      \
+    cp = result = alloca (len);						      \
+    for (cnt = 0; cnt < sizeof (all) / sizeof (all[0]); ++cnt)		      \
+      cp = stpcpy (cp, all[cnt]);					      \
+									      \
+    result;								      \
+  })
+
+
+static inline struct link_map *
+find_needed (struct link_map *map, const char *name)
+{
+  unsigned int n;
+
+  for (n = 0; n < map->l_nsearchlist; ++n)
+    if (_dl_does_name_match_p (name, map->l_searchlist[n]))
+      return map->l_searchlist[n];
+
+  /* Should never happen.  */
+  return NULL;
+}
+
+
+static int
+match_symbol (const char *name, ElfW(Word) hash, const char *string,
+	      struct link_map *map, int verbose, int weak)
+{
+  const char *strtab = (const char *) (map->l_addr
+				       + map->l_info[DT_STRTAB]->d_un.d_ptr);
+  ElfW(Addr) def_offset = map->l_info[VERSTAG (DT_VERDEF)]->d_un.d_ptr;
+  ElfW(Verdef) *def;
+
+  if (def_offset == 0)
+    {
+      /* The file has no symbol versioning.  I.e., the dependent
+	 object was linked against another version of this file.  We
+	 only print a message if verbose output is requested.  */
+      if (verbose)
+	_dl_signal_error (0, map->l_name, make_string ("\
+no version information available (required by ",
+						       name, ")"));
+      return 0;
+    }
+
+  def = (ElfW(Verdef) *) (map->l_addr + def_offset);
+  while (1)
+    {
+      /* Currently the version number of the definition entry is 1.
+	 Make sure all we see is this version.  */
+      if (def->vd_version  != 1)
+	{
+	  char buf[20];
+	  buf[sizeof (buf) - 1] = '\0';
+	  _dl_signal_error (0, map->l_name,
+			    make_string ("unsupported version ",
+					 _itoa_word (def->vd_version,
+						     &buf[sizeof (buf) - 1],
+						     10, 0),
+					 " of Verdef record"));
+	  return 1;
+	}
+
+      /* Compare the hash values.  */
+      if (hash == def->vd_hash)
+	{
+	  ElfW(Verdaux) *aux = (ElfW(Verdaux) *) ((char *) def + def->vd_aux);
+
+	  /* To be safe, compare the string as well.  */
+	  if (strcmp (string, strtab + aux->vda_name) == 0)
+	    /* Bingo!  */
+	    return 0;
+	}
+
+      /* If no more definitions we failed to find what we want.  */
+      if (def->vd_next == 0)
+	break;
+
+      /* Next definition.  */
+      def = (ElfW(Verdef) *) ((char *) def + def->vd_next);
+    }
+
+  /* Symbol not found.  If it was a weak reference it is not fatal.  */
+  if (weak)
+    {
+      if (verbose)
+	_dl_signal_error (0, map->l_name,
+			  make_string ("weak version `", string,
+				       "' not found (required by ", name,
+				       ")"));
+      return 0;
+    }
+
+  _dl_signal_error (0, map->l_name,
+		    make_string ("version `", string,
+				 "' not found (required by ", name, ")"));
+  return 1;
+}
+
+
+int
+_dl_check_map_versions (struct link_map *map, int verbose)
+{
+  int result = 0;
+  const char *strtab = (const char *) (map->l_addr
+				       + map->l_info[DT_STRTAB]->d_un.d_ptr);
+  /* Pointer to section with needed versions.  */
+  ElfW(Dyn) *dyn = map->l_info[VERSTAG (DT_VERNEED)];
+  /* Pointer to dynamic section with definitions.  */
+  ElfW(Dyn) *def = map->l_info[VERSTAG (DT_VERDEF)];
+  /* We need to find out which is the highest version index used
+    in a dependecy.  */
+  unsigned int ndx_high = 0;
+
+  if (dyn != NULL)
+    {
+      /* This file requires special versions from its dependencies.  */
+      ElfW(Verneed) *ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
+
+      /* Currently the version number of the needed entry is 1.
+	 Make sure all we see is this version.  */
+      if (ent->vn_version  != 1)
+	{
+	  char buf[20];
+	  buf[sizeof (buf) - 1] = '\0';
+	  _dl_signal_error (0, (*map->l_name ? map->l_name : _dl_argv[0]),
+			    make_string ("unsupported version ",
+					 _itoa_word (ent->vn_version,
+						     &buf[sizeof (buf) - 1],
+						     10, 0),
+					 " of Verneed record\n"));
+	  return 1;
+	}
+
+      while (1)
+	{
+	  ElfW(Vernaux) *aux;
+	  struct link_map *needed = find_needed (map, strtab + ent->vn_file);
+
+	  /* If NEEDED is NULL this means a dependency was not found
+	     and no stub entry was created.  This should never happen.  */
+	  assert (needed != NULL);
+
+	  /* NEEDED is the map for the file we need.  Now look for the
+	     dependency symbols.  */
+	  aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
+	  while (1)
+	    {
+	      /* Match the symbol.  */
+	      result |= match_symbol ((*map->l_name
+				       ? map->l_name : _dl_argv[0]),
+				      aux->vna_hash,
+				      strtab + aux->vna_name,
+				      needed, verbose,
+				      aux->vna_flags & VER_FLG_WEAK);
+
+	      /* Compare the version index.  */
+	      if ((aux->vna_other & 0x7fff) > ndx_high)
+		ndx_high = aux->vna_other & 0x7fff;
+
+	      if (aux->vna_next == 0)
+		/* No more symbols.  */
+		break;
+
+	      /* Next symbol.  */
+	      aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next);
+	    }
+
+	  if (ent->vn_next == 0)
+	    /* No more dependencies.  */
+	    break;
+
+	  /* Next dependency.  */
+	  ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
+	}
+    }
+
+  /* We also must store the names of the defined versions.  Determine
+     the maximum index here as well.
+
+     XXX We could avoid the loop by just taking the number of definitions
+     as an upper bound of new indeces.  */
+  if (def != NULL)
+    {
+      ElfW(Verdef) *ent;
+      ent = (ElfW(Verdef)  *) (map->l_addr + def->d_un.d_ptr);
+      while (1)
+	{
+	  if ((ent->vd_ndx & 0x7fff) > ndx_high)
+	    ndx_high = ent->vd_ndx & 0x7fff;
+
+	  if (ent->vd_next == 0)
+	    /* No more definitions.  */
+	    break;
+
+	  ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
+	}
+    }
+
+  if (ndx_high > 0)
+    {
+      /* Now we are ready to build the array with the version names
+	 which can be indexed by the version index in the VERSYM
+	 section.  */
+      map->l_versions = (hash_name_pair*) malloc ((ndx_high + 1)
+						  * sizeof (hash_name_pair));
+      memset (map->l_versions, '\0', (ndx_high + 1) * sizeof (hash_name_pair));
+      if (map->l_versions == NULL)
+	{
+	  _dl_signal_error (ENOMEM, (*map->l_name ? map->l_name : _dl_argv[0]),
+			    "cannot allocate version name table");
+	  result = 1;
+	}
+      else
+	{
+	  /* Store the number of available symbols.  */
+	  map->l_nversions = ndx_high + 1;
+
+	  if (dyn != NULL)
+	    {
+	      ElfW(Verneed) *ent;
+	      ent = (ElfW(Verneed) *) (map->l_addr + dyn->d_un.d_ptr);
+	      while (1)
+		{
+		  ElfW(Vernaux) *aux;
+		  aux = (ElfW(Vernaux) *) ((char *) ent + ent->vn_aux);
+		  while (1)
+		    {
+		      ElfW(Half) ndx = aux->vna_other & 0x7fff;
+		      map->l_versions[ndx].hash = aux->vna_hash;
+		      map->l_versions[ndx].name = &strtab[aux->vna_name];
+
+		      if (aux->vna_next == 0)
+			/* No more symbols.  */
+			break;
+
+		      /* Advance to next symbol.  */
+		      aux = (ElfW(Vernaux) *) ((char *) aux + aux->vna_next);
+		    }
+
+		  if (ent->vn_next == 0)
+		    /* No more dependencies.  */
+		    break;
+
+		  /* Advance to next dependency.  */
+		  ent = (ElfW(Verneed) *) ((char *) ent + ent->vn_next);
+		}
+	    }
+
+	  /* And insert the defined versions.  */
+	  if (def != NULL)
+	    {
+	      ElfW(Verdef) *ent;
+	      ent = (ElfW(Verdef)  *) (map->l_addr + def->d_un.d_ptr);
+	      while (1)
+		{
+		  ElfW(Verdaux) *aux;
+		  aux = (ElfW(Verdaux) *) ((char *) ent + ent->vd_aux);
+
+		  if ((ent->vd_flags & VER_FLG_BASE) == 0)
+		    {
+		      /* The name of the base version should not be
+			 available for matching a versioned symbol.  */
+		      ElfW(Half) ndx = ent->vd_ndx & 0x7fff;
+		      map->l_versions[ndx].hash = ent->vd_hash;
+		      map->l_versions[ndx].name = &strtab[aux->vda_name];
+		    }
+
+		  if (ent->vd_next == 0)
+		    /* No more definitions.  */
+		    break;
+
+		  ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
+		}
+	    }
+	}
+    }
+
+  return result;
+}
+
+
+int
+_dl_check_all_versions (struct link_map *map, int verbose)
+{
+  struct link_map *l;
+  int result = 0;
+
+  for (l = map; l != NULL; l = l->l_next)
+    result |= _dl_check_map_versions (l, verbose);
+
+  return result;
+}