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glibc  2.9
Defines | Functions
dl-version.c File Reference
#include <elf.h>
#include <errno.h>
#include <libintl.h>
#include <stdlib.h>
#include <string.h>
#include <ldsodefs.h>
#include <stdio-common/_itoa.h>
#include <assert.h>

Go to the source code of this file.

Defines

#define VERSYMIDX(tag)   (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag))
#define make_string(string, rest...)

Functions

static struct link_map__attribute ((always_inline))
static int internal_function match_symbol (const char *name, Lmid_t ns, ElfW(Word) hash, const char *string, struct link_map *map, int verbose, int weak)
int internal_function _dl_check_map_versions (struct link_map *map, int verbose, int trace_mode)
int internal_function _dl_check_all_versions (struct link_map *map, int verbose, int trace_mode)

Define Documentation

#define make_string (   string,
  rest... 
)
Value:
({                                                                   \
    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;                                                          \
  })

Definition at line 37 of file dl-version.c.

#define VERSYMIDX (   tag)    (DT_NUM + DT_THISPROCNUM + DT_VERSIONTAGIDX (tag))

Definition at line 33 of file dl-version.c.


Function Documentation

static struct link_map* __attribute ( (always_inline)  ) [static, read]

Definition at line 56 of file dl-version.c.

{
  struct link_map *tmap;
  unsigned int n;

  for (tmap = GL(dl_ns)[map->l_ns]._ns_loaded; tmap != NULL;
       tmap = tmap->l_next)
    if (_dl_name_match_p (name, tmap))
      return tmap;

  /* The required object is not in the global scope, look to see if it is
     a dependency of the current object.  */
  for (n = 0; n < map->l_searchlist.r_nlist; n++)
    if (_dl_name_match_p (name, map->l_searchlist.r_list[n]))
      return map->l_searchlist.r_list[n];

  /* Should never happen.  */
  return NULL;
}

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int internal_function _dl_check_all_versions ( struct link_map map,
int  verbose,
int  trace_mode 
)

Definition at line 382 of file dl-version.c.

{
  struct link_map *l;
  int result = 0;

  for (l = map; l != NULL; l = l->l_next)
    result |= (! l->l_faked
              && _dl_check_map_versions (l, verbose, trace_mode));

  return result;
}

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int internal_function _dl_check_map_versions ( struct link_map map,
int  verbose,
int  trace_mode 
)

Definition at line 179 of file dl-version.c.

{
  int result = 0;
  const char *strtab;
  /* Pointer to section with needed versions.  */
  ElfW(Dyn) *dyn;
  /* Pointer to dynamic section with definitions.  */
  ElfW(Dyn) *def;
  /* We need to find out which is the highest version index used
    in a dependecy.  */
  unsigned int ndx_high = 0;
  /* Initialize to make the compiler happy.  */
  const char *errstring = NULL;
  int errval = 0;

  /* If we don't have a string table, we must be ok.  */
  if (map->l_info[DT_STRTAB] == NULL)
    return 0;
  strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);

  dyn = map->l_info[VERSYMIDX (DT_VERNEED)];
  def = map->l_info[VERSYMIDX (DT_VERDEF)];

  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 (__builtin_expect (ent->vn_version, 1) != 1)
       {
         char buf[20];
         buf[sizeof (buf) - 1] = '\0';
         /* XXX We cannot translate the message.  */
         errstring = make_string ("unsupported version ",
                               _itoa (ent->vn_version,
                                     &buf[sizeof (buf) - 1], 10, 0),
                               " of Verneed record\n");
       call_error:
         _dl_signal_error (errval, *map->l_name ? map->l_name : rtld_progname,
                         NULL, errstring);
       }

      while (1)
       {
         ElfW(Vernaux) *aux;
         struct link_map *needed = find_needed (strtab + ent->vn_file, map);

         /* If NEEDED is NULL this means a dependency was not found
            and no stub entry was created.  This should never happen.  */
         assert (needed != NULL);

         /* Make sure this is no stub we created because of a missing
            dependency.  */
         if (__builtin_expect (! trace_mode, 1)
             || ! __builtin_expect (needed->l_faked, 0))
           {
             /* 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 : rtld_progname),
                                     map->l_ns, aux->vna_hash,
                                     strtab + aux->vna_name,
                                     needed->l_real, verbose,
                                     aux->vna_flags & VER_FLG_WEAK);

                /* Compare the version index.  */
                if ((unsigned int) (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 ((unsigned int) (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 = (struct r_found_version *)
       calloc (ndx_high + 1, sizeof (*map->l_versions));
      if (__builtin_expect (map->l_versions == NULL, 0))
       {
         errstring = N_("cannot allocate version reference table");
         errval = ENOMEM;
         goto call_error;
       }

      /* Store the number of available symbols.  */
      map->l_nversions = ndx_high + 1;

      /* Compute the pointer to the version symbols.  */
      map->l_versyms = (void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);

      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].hidden = aux->vna_other & 0x8000;
                map->l_versions[ndx].name = &strtab[aux->vna_name];
                map->l_versions[ndx].filename = &strtab[ent->vn_file];

                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];
                map->l_versions[ndx].filename = NULL;
              }

             if (ent->vd_next == 0)
              /* No more definitions.  */
              break;

             ent = (ElfW(Verdef) *) ((char *) ent + ent->vd_next);
           }
       }
    }

  return result;
}

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static int internal_function match_symbol ( const char *  name,
Lmid_t  ns,
ElfW(Word)  hash,
const char *  string,
struct link_map map,
int  verbose,
int  weak 
) [static]

Definition at line 80 of file dl-version.c.

{
  const char *strtab = (const void *) D_PTR (map, l_info[DT_STRTAB]);
  ElfW(Addr) def_offset;
  ElfW(Verdef) *def;
  /* Initialize to make the compiler happy.  */
  const char *errstring = NULL;
  int result = 0;

  /* Display information about what we are doing while debugging.  */
  if (__builtin_expect (GLRO(dl_debug_mask) & DL_DEBUG_VERSIONS, 0))
    _dl_debug_printf ("\
checking for version `%s' in file %s [%lu] required by file %s [%lu]\n",
                    string, map->l_name[0] ? map->l_name : rtld_progname,
                    map->l_ns, name, ns);

  if (__builtin_expect (map->l_info[VERSYMIDX (DT_VERDEF)] == NULL, 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)
       {
         /* XXX We cannot translate the messages.  */
         errstring = make_string ("\
no version information available (required by ", name, ")");
         goto call_cerror;
       }
      return 0;
    }

  def_offset = map->l_info[VERSYMIDX (DT_VERDEF)]->d_un.d_ptr;
  assert (def_offset != 0);

  def = (ElfW(Verdef) *) ((char *) 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 (__builtin_expect (def->vd_version, 1) != 1)
       {
         char buf[20];
         buf[sizeof (buf) - 1] = '\0';
         /* XXX We cannot translate the message.  */
         errstring = make_string ("unsupported version ",
                               _itoa (def->vd_version,
                                     &buf[sizeof (buf) - 1], 10, 0),
                               " of Verdef record");
         result = 1;
         goto call_cerror;
       }

      /* 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 (__builtin_expect (strcmp (string, strtab + aux->vda_name), 0)
             == 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 (__builtin_expect (weak, 1))
    {
      if (verbose)
       {
         /* XXX We cannot translate the message.  */
         errstring = make_string ("weak version `", string,
                               "' not found (required by ", name, ")");
         goto call_cerror;
       }
      return 0;
    }

  /* XXX We cannot translate the message.  */
  errstring = make_string ("version `", string, "' not found (required by ",
                        name, ")");
  result = 1;
 call_cerror:
  _dl_signal_cerror (0, map->l_name[0] ? map->l_name : rtld_progname,
                   NULL, errstring);
  return result;
}

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