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[BZ #15022] Correct global-scope dlopen issues in static executables.

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This change creates a link map in static executables to serve as the
global search list for dlopen.  It fixes a problem with the inability
to access the global symbol object and a crash on an attempt to map a
DSO into the global scope.  Some code that has become dead after the
addition of this link map is removed too and test cases are provided.
This commit is contained in:
Maciej W. Rozycki
2013-06-28 16:20:26 +01:00
parent ed0257f7d3
commit f91f1c0fb8
9 changed files with 610 additions and 42 deletions
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51
elf/dl-support.c
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@ -70,17 +70,52 @@ const char *_dl_origin_path;
/* Nonzero if runtime lookup should not update the .got/.plt. */
int _dl_bind_not;
/* A dummy link map for the executable, used by dlopen to access the global
scope. We don't export any symbols ourselves, so this can be minimal. */
static struct link_map _dl_main_map =
{
.l_name = (char *) "",
.l_real = &_dl_main_map,
.l_ns = LM_ID_BASE,
.l_libname = &(struct libname_list) { .name = "", .dont_free = 1 },
.l_searchlist =
{
.r_list = &(struct link_map *) { &_dl_main_map },
.r_nlist = 1,
},
.l_symbolic_searchlist = { .r_list = &(struct link_map *) { NULL } },
.l_type = lt_executable,
.l_scope_mem = { &_dl_main_map.l_searchlist },
.l_scope_max = (sizeof (_dl_main_map.l_scope_mem)
/ sizeof (_dl_main_map.l_scope_mem[0])),
.l_scope = _dl_main_map.l_scope_mem,
.l_local_scope = { &_dl_main_map.l_searchlist },
.l_used = 1,
.l_tls_offset = NO_TLS_OFFSET,
.l_serial = 1,
};
/* Namespace information. */
struct link_namespaces _dl_ns[DL_NNS];
size_t _dl_nns;
struct link_namespaces _dl_ns[DL_NNS] =
{
[LM_ID_BASE] =
{
._ns_loaded = &_dl_main_map,
._ns_nloaded = 1,
._ns_main_searchlist = &_dl_main_map.l_searchlist,
}
};
size_t _dl_nns = 1;
/* Incremented whenever something may have been added to dl_loaded. */
unsigned long long _dl_load_adds;
unsigned long long _dl_load_adds = 1;
/* Fake scope. In dynamically linked binaries this is the scope of the
main application but here we don't have something like this. So
create a fake scope containing nothing. */
struct r_scope_elem _dl_initial_searchlist;
/* Fake scope of the main application. */
struct r_scope_elem _dl_initial_searchlist =
{
.r_list = &(struct link_map *) { &_dl_main_map },
.r_nlist = 1,
};
#ifndef HAVE_INLINED_SYSCALLS
/* Nonzero during startup. */
@ -265,6 +300,8 @@ void
internal_function
_dl_non_dynamic_init (void)
{
_dl_main_map.l_origin = _dl_get_origin ();
if (HP_TIMING_AVAIL)
HP_TIMING_NOW (_dl_cpuclock_offset);