Implement lookup by DT_SONAME
This CL also fixes SEARCH_NAME hack and resolves
https://code.google.com/p/android/issues/detail?id=6670
once and for all.
Bug: https://code.google.com/p/android/issues/detail?id=6670
Change-Id: I9b8d6a672cd722f30fbfbb40cdee8d9b39cfe56e
diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 9a8dbc9..64df7a5 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -248,6 +248,7 @@
__libdl_info.ref_count_ = 1;
__libdl_info.strtab_size_ = sizeof(ANDROID_LIBDL_STRTAB);
__libdl_info.local_group_root_ = &__libdl_info;
+ __libdl_info.soname_ = "libdl.so";
}
return &__libdl_info;
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 3960f9a..44ae4d4 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -78,19 +78,6 @@
#undef ELF_ST_TYPE
#define ELF_ST_TYPE(x) (static_cast<uint32_t>(x) & 0xf)
-#if defined(__LP64__)
-#define SEARCH_NAME(x) x
-#else
-// Nvidia drivers are relying on the bug:
-// http://code.google.com/p/android/issues/detail?id=6670
-// so we continue to use base-name lookup for lp32
-static const char* get_base_name(const char* name) {
- const char* bname = strrchr(name, '/');
- return bname ? bname + 1 : name;
-}
-#define SEARCH_NAME(x) get_base_name(x)
-#endif
-
static ElfW(Addr) get_elf_exec_load_bias(const ElfW(Ehdr)* elf);
static LinkerTypeAllocator<soinfo> g_soinfo_allocator;
@@ -1029,7 +1016,7 @@
return nullptr;
}
- soinfo* si = soinfo_alloc(SEARCH_NAME(name), &file_stat, file_offset, rtld_flags);
+ soinfo* si = soinfo_alloc(name, &file_stat, file_offset, rtld_flags);
if (si == nullptr) {
return nullptr;
}
@@ -1051,10 +1038,15 @@
return si;
}
-static soinfo *find_loaded_library_by_name(const char* name) {
- const char* search_name = SEARCH_NAME(name);
+static soinfo *find_loaded_library_by_soname(const char* name) {
+ // Ignore filename with path.
+ if (strchr(name, '/') != nullptr) {
+ return nullptr;
+ }
+
for (soinfo* si = solist; si != nullptr; si = si->next) {
- if (!strcmp(search_name, si->name)) {
+ const char* soname = si->get_soname();
+ if (soname != nullptr && (strcmp(name, soname) == 0)) {
return si;
}
}
@@ -1062,13 +1054,12 @@
}
static soinfo* find_library_internal(LoadTaskList& load_tasks, const char* name, int rtld_flags, const android_dlextinfo* extinfo) {
-
- soinfo* si = find_loaded_library_by_name(name);
+ soinfo* si = find_loaded_library_by_soname(name);
// Library might still be loaded, the accurate detection
// of this fact is done by load_library.
if (si == nullptr) {
- TRACE("[ '%s' has not been found by name. Trying harder...]", name);
+ TRACE("[ '%s' has not been found by soname. Trying harder...]", name);
si = load_library(load_tasks, name, rtld_flags, extinfo);
}
@@ -1832,6 +1823,7 @@
return 0;
}
+
void soinfo::set_dt_flags_1(uint32_t dt_flags_1) {
if (has_min_version(1)) {
if ((dt_flags_1 & DF_1_GLOBAL) != 0) {
@@ -1846,6 +1838,14 @@
}
}
+const char* soinfo::get_soname() {
+ if (has_min_version(2)) {
+ return soname_;
+ } else {
+ return name;
+ }
+}
+
// This is a return on get_children()/get_parents() if
// 'this->flags' does not have FLAG_NEW_SOINFO set.
static soinfo::soinfo_list_t g_empty_list;
@@ -2012,14 +2012,17 @@
#endif
// Extract useful information from dynamic section.
+ // Note that: "Except for the DT_NULL element at the end of the array,
+ // and the relative order of DT_NEEDED elements, entries may appear in any order."
+ //
+ // source: http://www.sco.com/developers/gabi/1998-04-29/ch5.dynamic.html
uint32_t needed_count = 0;
for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
DEBUG("d = %p, d[0](tag) = %p d[1](val) = %p",
d, reinterpret_cast<void*>(d->d_tag), reinterpret_cast<void*>(d->d_un.d_val));
switch (d->d_tag) {
case DT_SONAME:
- // TODO: glibc dynamic linker uses this name for
- // initial library lookup; consider doing the same here.
+ // this is parsed after we have strtab initialized (see below).
break;
case DT_HASH:
@@ -2342,6 +2345,14 @@
}
}
+ // second pass - parse entries relying on strtab
+ for (ElfW(Dyn)* d = dynamic; d->d_tag != DT_NULL; ++d) {
+ if (d->d_tag == DT_SONAME) {
+ soname_ = get_string(d->d_un.d_val);
+ break;
+ }
+ }
+
DEBUG("si->base = %p, si->strtab = %p, si->symtab = %p",
reinterpret_cast<void*>(base), strtab_, symtab_);
diff --git a/linker/linker.h b/linker/linker.h
index e4681eb..04acda4 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -92,7 +92,7 @@
#define SUPPORTED_DT_FLAGS_1 (DF_1_NOW | DF_1_GLOBAL | DF_1_NODELETE)
-#define SOINFO_VERSION 1
+#define SOINFO_VERSION 2
#define SOINFO_NAME_LEN 128
@@ -278,6 +278,8 @@
soinfo* get_local_group_root() const;
+ const char* get_soname();
+
private:
ElfW(Sym)* elf_lookup(SymbolName& symbol_name);
ElfW(Sym)* elf_addr_lookup(const void* addr);
@@ -322,6 +324,8 @@
uint8_t* android_relocs_;
size_t android_relocs_size_;
+ const char* soname_;
+
friend soinfo* get_libdl_info();
};
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index ef4ff20..2bd9476 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -97,6 +97,32 @@
ASSERT_EQ(0, dlclose(handle2));
}
+TEST(dlfcn, dlopen_by_soname) {
+ static const char* soname = "libdlext_test_soname.so";
+ static const char* filename = "libdlext_test_different_soname.so";
+ // 1. Make sure there is no library with soname in default search path
+ void* handle = dlopen(soname, RTLD_NOW);
+ ASSERT_TRUE(handle == nullptr);
+
+ // 2. Load a library using filename
+ handle = dlopen(filename, RTLD_NOW);
+ ASSERT_TRUE(handle != nullptr) << dlerror();
+
+ // 3. Find library by soname
+ void* handle_soname = dlopen(soname, RTLD_NOW | RTLD_NOLOAD);
+ ASSERT_TRUE(handle_soname != nullptr) << dlerror();
+ ASSERT_EQ(handle, handle_soname);
+
+ // 4. RTLD_NOLOAD should still work with filename
+ void* handle_filename = dlopen(filename, RTLD_NOW | RTLD_NOLOAD);
+ ASSERT_TRUE(handle_filename != nullptr) << dlerror();
+ ASSERT_EQ(handle, handle_filename);
+
+ dlclose(handle_filename);
+ dlclose(handle_soname);
+ dlclose(handle);
+}
+
// ifuncs are only supported on intel and arm64 for now
#if defined (__aarch64__) || defined(__i386__) || defined(__x86_64__)
TEST(dlfcn, ifunc) {
diff --git a/tests/libs/Android.mk b/tests/libs/Android.mk
index 7ca856c..665ce0c 100644
--- a/tests/libs/Android.mk
+++ b/tests/libs/Android.mk
@@ -117,6 +117,17 @@
build_target := SHARED_LIBRARY
include $(TEST_PATH)/Android.build.mk
+# ----------------------------------------------------------------------------
+# Library with soname which does not match filename
+# ----------------------------------------------------------------------------
+libdlext_test_different_soname_src_files := \
+ dlext_test_library.cpp \
+
+module := libdlext_test_different_soname
+module_tag := optional
+libdlext_test_different_soname_ldflags := -Wl,-soname=libdlext_test_soname.so
+include $(LOCAL_PATH)/Android.build.testlib.mk
+
# -----------------------------------------------------------------------------
# Library used by dlext tests - zipped and aligned
# -----------------------------------------------------------------------------
