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authorFilippo Arcidiacono <filippo.arcidiacono@st.com>2010-07-29 11:35:05 +0200
committerCarmelo Amoroso <carmelo.amoroso@st.com>2010-09-17 16:07:25 +0200
commit94cc6edb78a12655c0602a246fa1cbdc8c6d0ad9 (patch)
tree4dcffeee2396c0cd7d7b30f5a493c31ad7e171ad /ldso/libdl/libdl.c
parent637e2b2440f69e22932edd71bd2f0b1210dc32ea (diff)
ldso: Rework global scope handling and symbol lookup mechanism
Global symbol scope is implemented as a linked list of local scope, that dynamically grows and shrinks when dlopen/ dlclose are called. Each local scope is implemented as an array of pointer to struct elf_resolve. This will help to detect conflict when LD_TRACE_PRELINKING option will be implemented. Signed-off-by: Filippo Arcidiacono <filippo.arcidiacono@st.com> Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>
Diffstat (limited to 'ldso/libdl/libdl.c')
-rw-r--r--ldso/libdl/libdl.c59
1 files changed, 55 insertions, 4 deletions
diff --git a/ldso/libdl/libdl.c b/ldso/libdl/libdl.c
index 3957e846f..b641fe366 100644
--- a/ldso/libdl/libdl.c
+++ b/ldso/libdl/libdl.c
@@ -55,7 +55,7 @@ extern struct link_map *_dl_update_slotinfo(unsigned long int req_modid);
extern struct elf_resolve * _dl_load_shared_library(int, struct dyn_elf **,
struct elf_resolve *, char *, int);
-extern int _dl_fixup(struct dyn_elf *rpnt, int lazy);
+extern int _dl_fixup(struct dyn_elf *rpnt, struct r_scope_elem *scope, int lazy);
extern void _dl_protect_relro(struct elf_resolve * tpnt);
extern int _dl_errno;
extern struct dyn_elf *_dl_symbol_tables;
@@ -271,6 +271,21 @@ void dl_cleanup(void)
}
}
+static ptrdiff_t _dl_build_local_scope (struct elf_resolve **list,
+ struct elf_resolve *map)
+{
+ struct elf_resolve **p = list;
+ struct init_fini_list *q;
+
+ *p++ = map;
+ map->init_flag |= DL_RESERVED;
+ if (map->init_fini)
+ for (q = map->init_fini; q; q = q->next)
+ if (! (q->tpnt->init_flag & DL_RESERVED))
+ p += _dl_build_local_scope (p, q->tpnt);
+ return p - list;
+}
+
void *dlopen(const char *libname, int flag)
{
struct elf_resolve *tpnt, *tfrom;
@@ -283,6 +298,8 @@ void *dlopen(const char *libname, int flag)
unsigned int nlist, i;
struct elf_resolve **init_fini_list;
static bool _dl_init;
+ struct elf_resolve **local_scope;
+ struct r_scope_elem *ls;
#if defined(USE_TLS) && USE_TLS
bool any_tls = false;
#endif
@@ -458,6 +475,23 @@ void *dlopen(const char *libname, int flag)
}
}
+ /* Build the local scope for the dynamically loaded modules. */
+ local_scope = _dl_malloc(nlist * sizeof(struct elf_resolve *)); /* Could it allocated on stack? */
+ for (i = 0; i < nlist; i++)
+ if (init_fini_list[i]->symbol_scope.r_nlist == 0) {
+ int k, cnt;
+ cnt = _dl_build_local_scope(local_scope, init_fini_list[i]);
+ init_fini_list[i]->symbol_scope.r_list = _dl_malloc(cnt * sizeof(struct elf_resolve *));
+ init_fini_list[i]->symbol_scope.r_nlist = cnt;
+ _dl_memcpy (init_fini_list[i]->symbol_scope.r_list, local_scope,
+ cnt * sizeof (struct elf_resolve *));
+ /* Restoring the init_flag.*/
+ for (k = 0; k < nlist; k++)
+ init_fini_list[k]->init_flag &= ~DL_RESERVED;
+ }
+
+ _dl_free(local_scope);
+
/* Sort the INIT/FINI list in dependency order. */
for (runp2 = dep_list; runp2; runp2 = runp2->next) {
unsigned int j, k;
@@ -505,8 +539,13 @@ void *dlopen(const char *libname, int flag)
*/
_dl_perform_mips_global_got_relocations(tpnt, !now_flag);
#endif
+ /* Get the tail of the list */
+ for (ls = &_dl_loaded_modules->symbol_scope; ls && ls->next; ls = ls->next);
- if (_dl_fixup(dyn_chain, now_flag))
+ /* Extend the global scope by adding the local scope of the dlopened DSO. */
+ ls->next = &dyn_chain->dyn->symbol_scope;
+
+ if (_dl_fixup(dyn_chain, &_dl_loaded_modules->symbol_scope, now_flag))
goto oops;
if (relro_ptr) {
@@ -667,7 +706,7 @@ void *dlsym(void *vhandle, const char *name)
tpnt = NULL;
if (handle == _dl_symbol_tables)
tpnt = handle->dyn; /* Only search RTLD_GLOBAL objs if global object */
- ret = _dl_find_hash(name2, handle, NULL, 0, &tls_tpnt);
+ ret = _dl_find_hash(name2, &handle->dyn->symbol_scope, NULL, 0, &tls_tpnt);
#if defined(USE_TLS) && USE_TLS && defined SHARED
if (tls_tpnt) {
@@ -708,6 +747,7 @@ static int do_dlclose(void *vhandle, int need_fini)
struct dyn_elf *handle;
unsigned int end;
unsigned int i, j;
+ struct r_scope_elem *ls;
#if defined(USE_TLS) && USE_TLS
bool any_tls = false;
size_t tls_free_start = NO_TLS_OFFSET;
@@ -873,7 +913,7 @@ static int do_dlclose(void *vhandle, int need_fini)
}
#endif
- DL_LIB_UNMAP (tpnt, end);
+ DL_LIB_UNMAP (tpnt, end - tpnt->mapaddr);
/* Free elements in RTLD_LOCAL scope list */
for (runp = tpnt->rtld_local; runp; runp = tmp) {
tmp = runp->next;
@@ -897,6 +937,16 @@ static int do_dlclose(void *vhandle, int need_fini)
}
}
+ if (handle->dyn == tpnt) {
+ /* Unlink the local scope from global one */
+ for (ls = &_dl_loaded_modules->symbol_scope; ls; ls = ls->next)
+ if (ls->next->r_list[0] == tpnt) {
+ _dl_if_debug_print("removing symbol_scope: %s\n", tpnt->libname);
+ break;
+ }
+ ls->next = ls->next->next;
+ }
+
/* Next, remove tpnt from the global symbol table list */
if (_dl_symbol_tables) {
if (_dl_symbol_tables->dyn == tpnt) {
@@ -918,6 +968,7 @@ static int do_dlclose(void *vhandle, int need_fini)
}
}
free(tpnt->libname);
+ free(tpnt->symbol_scope.r_list);
free(tpnt);
}
}