Add RTLD_NOLOAD support and some related changes.
* Aligned RTLD_ values with glibc for lp64
* dlopen supports RTLD_NOLOAD flag
* soinfo_unload calls find_library(.., RTLD_NOLOAD)
instead of naive find_loaded_library_by_name()
* dlopen changed to add child to caller soinfo instead
of somain.
Bug: https://code.google.com/p/android/issues/detail?id=64069
Change-Id: I1a65f2c34f3e0edc6d2c41a2e408b58195feb640
diff --git a/libc/include/dlfcn.h b/libc/include/dlfcn.h
index 7daa8f7..8dde08c 100644
--- a/libc/include/dlfcn.h
+++ b/libc/include/dlfcn.h
@@ -50,15 +50,29 @@
extern int dladdr(const void* addr, Dl_info *info);
enum {
+#if defined(__LP64__)
+ RTLD_NOW = 2,
+#else
RTLD_NOW = 0,
+#endif
RTLD_LAZY = 1,
RTLD_LOCAL = 0,
+#if defined(__LP64__)
+ RTLD_GLOBAL = 0x00100,
+#else
RTLD_GLOBAL = 2,
+#endif
+ RTLD_NOLOAD = 4,
};
+#if defined (__LP64__)
+#define RTLD_DEFAULT ((void*) 0)
+#define RTLD_NEXT ((void*) -1L)
+#else
#define RTLD_DEFAULT ((void*) 0xffffffff)
#define RTLD_NEXT ((void*) 0xfffffffe)
+#endif
__END_DECLS
diff --git a/linker/dlfcn.cpp b/linker/dlfcn.cpp
index 85e91c3..8ef1212 100644
--- a/linker/dlfcn.cpp
+++ b/linker/dlfcn.cpp
@@ -65,10 +65,10 @@
do_android_update_LD_LIBRARY_PATH(ld_library_path);
}
-void* android_dlopen_ext(const char* filename, int flags, const android_dlextinfo* extinfo)
-{
+static void* dlopen_ext(const char* filename, int flags, const android_dlextinfo* extinfo, const void* caller_addr) {
ScopedPthreadMutexLocker locker(&g_dl_mutex);
- soinfo* result = do_dlopen(filename, flags, extinfo);
+ soinfo* caller_soinfo = find_containing_library(caller_addr);
+ soinfo* result = do_dlopen(filename, flags, caller_soinfo, extinfo);
if (result == NULL) {
__bionic_format_dlerror("dlopen failed", linker_get_error_buffer());
return NULL;
@@ -76,8 +76,14 @@
return result;
}
+void* android_dlopen_ext(const char* filename, int flags, const android_dlextinfo* extinfo) {
+ void* caller_addr = __builtin_return_address(0);
+ return dlopen_ext(filename, flags, extinfo, caller_addr);
+}
+
void* dlopen(const char* filename, int flags) {
- return android_dlopen_ext(filename, flags, NULL);
+ void* caller_addr = __builtin_return_address(0);
+ return dlopen_ext(filename, flags, NULL, caller_addr);
}
void* dlsym(void* handle, const char* symbol) {
@@ -97,8 +103,8 @@
if (handle == RTLD_DEFAULT) {
sym = dlsym_linear_lookup(symbol, &found, NULL);
} else if (handle == RTLD_NEXT) {
- void* ret_addr = __builtin_return_address(0);
- soinfo* si = find_containing_library(ret_addr);
+ void* caller_addr = __builtin_return_address(0);
+ soinfo* si = find_containing_library(caller_addr);
sym = NULL;
if (si && si->next) {
@@ -151,7 +157,9 @@
int dlclose(void* handle) {
ScopedPthreadMutexLocker locker(&g_dl_mutex);
- return do_dlclose(reinterpret_cast<soinfo*>(handle));
+ do_dlclose(reinterpret_cast<soinfo*>(handle));
+ // dlclose has no defined errors.
+ return 0;
}
// name_offset: starting index of the name in libdl_info.strtab
diff --git a/linker/linker.cpp b/linker/linker.cpp
index 5861267..881bcc2 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -682,7 +682,7 @@
return fd;
}
-static soinfo* load_library(const char* name, const android_dlextinfo* extinfo) {
+static soinfo* load_library(const char* name, int dlflags, const android_dlextinfo* extinfo) {
// Open the file.
int fd = open_library(name);
if (fd == -1) {
@@ -710,6 +710,10 @@
}
}
+ if ((dlflags & RTLD_NOLOAD) != 0) {
+ return NULL;
+ }
+
// Read the ELF header and load the segments.
if (!elf_reader.Load(extinfo)) {
return NULL;
@@ -748,33 +752,37 @@
return NULL;
}
-static soinfo* find_library_internal(const char* name, const android_dlextinfo* extinfo) {
+static soinfo* find_library_internal(const char* name, int dlflags, const android_dlextinfo* extinfo) {
if (name == NULL) {
return somain;
}
soinfo* si = find_loaded_library_by_name(name);
- if (si != NULL) {
- if (si->flags & FLAG_LINKED) {
- return si;
- }
- DL_ERR("OOPS: recursive link to \"%s\"", si->name);
+
+ // Library might still be loaded, the accurate detection
+ // of this fact is done by load_library
+ if (si == NULL) {
+ TRACE("[ '%s' has not been found by name. Trying harder...]", name);
+ si = load_library(name, dlflags, extinfo);
+ }
+
+ if (si != NULL && (si->flags & FLAG_LINKED) == 0) {
+ DL_ERR("recursive link to \"%s\"", si->name);
return NULL;
}
- TRACE("[ '%s' has not been loaded yet. Locating...]", name);
- return load_library(name, extinfo);
+ return si;
}
-static soinfo* find_library(const char* name, const android_dlextinfo* extinfo) {
- soinfo* si = find_library_internal(name, extinfo);
+static soinfo* find_library(const char* name, int dlflags, const android_dlextinfo* extinfo) {
+ soinfo* si = find_library_internal(name, dlflags, extinfo);
if (si != NULL) {
si->ref_count++;
}
return si;
}
-static int soinfo_unload(soinfo* si) {
+static void soinfo_unload(soinfo* si) {
if (si->ref_count == 1) {
TRACE("unloading '%s'", si->name);
si->CallDestructors();
@@ -789,7 +797,14 @@
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
TRACE("%s needs to unload %s", si->name, library_name);
- soinfo_unload(find_loaded_library_by_name(library_name));
+ soinfo* needed = find_library(library_name, RTLD_NOLOAD, NULL);
+ if (needed != NULL) {
+ soinfo_unload(needed);
+ } else {
+ // Not found: for example if symlink was deleted between dlopen and dlclose
+ // Since we cannot really handle errors at this point - print and continue.
+ PRINT("warning: couldn't find %s needed by %s on unload.", library_name, si->name);
+ }
}
}
}
@@ -801,7 +816,6 @@
si->ref_count--;
TRACE("not unloading '%s', decrementing ref_count to %zd", si->name, si->ref_count);
}
- return 0;
}
void do_android_get_LD_LIBRARY_PATH(char* buffer, size_t buffer_size) {
@@ -814,8 +828,8 @@
}
}
-soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo) {
- if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL)) != 0) {
+soinfo* do_dlopen(const char* name, int flags, soinfo* caller, const android_dlextinfo* extinfo) {
+ if ((flags & ~(RTLD_NOW|RTLD_LAZY|RTLD_LOCAL|RTLD_GLOBAL|RTLD_NOLOAD)) != 0) {
DL_ERR("invalid flags to dlopen: %x", flags);
return NULL;
}
@@ -824,20 +838,21 @@
return NULL;
}
protect_data(PROT_READ | PROT_WRITE);
- soinfo* si = find_library(name, extinfo);
+ soinfo* si = find_library(name, flags, extinfo);
if (si != NULL) {
si->CallConstructors();
- somain->add_child(si);
+ if (caller != NULL) {
+ caller->add_child(si);
+ }
}
protect_data(PROT_READ);
return si;
}
-int do_dlclose(soinfo* si) {
+void do_dlclose(soinfo* si) {
protect_data(PROT_READ | PROT_WRITE);
- int result = soinfo_unload(si);
+ soinfo_unload(si);
protect_data(PROT_READ);
- return result;
}
#if defined(USE_RELA)
@@ -1435,6 +1450,10 @@
// DT_FINI should be called after DT_FINI_ARRAY if both are present.
CallFunction("DT_FINI", fini_func);
+
+ // This is needed on second call to dlopen
+ // after library has been unloaded with RTLD_NODELETE
+ constructors_called = false;
}
void soinfo::add_child(soinfo* child) {
@@ -1811,7 +1830,7 @@
memset(g_ld_preloads, 0, sizeof(g_ld_preloads));
size_t preload_count = 0;
for (size_t i = 0; g_ld_preload_names[i] != NULL; i++) {
- soinfo* lsi = find_library(g_ld_preload_names[i], NULL);
+ soinfo* lsi = find_library(g_ld_preload_names[i], 0, NULL);
if (lsi != NULL) {
g_ld_preloads[preload_count++] = lsi;
} else {
@@ -1829,7 +1848,7 @@
if (d->d_tag == DT_NEEDED) {
const char* library_name = si->strtab + d->d_un.d_val;
DEBUG("%s needs %s", si->name, library_name);
- soinfo* lsi = find_library(library_name, NULL);
+ soinfo* lsi = find_library(library_name, 0, NULL);
if (lsi == NULL) {
strlcpy(tmp_err_buf, linker_get_error_buffer(), sizeof(tmp_err_buf));
DL_ERR("could not load library \"%s\" needed by \"%s\"; caused by %s",
diff --git a/linker/linker.h b/linker/linker.h
index e5aca6e..9d4099d 100644
--- a/linker/linker.h
+++ b/linker/linker.h
@@ -231,8 +231,8 @@
void do_android_get_LD_LIBRARY_PATH(char*, size_t);
void do_android_update_LD_LIBRARY_PATH(const char* ld_library_path);
-soinfo* do_dlopen(const char* name, int flags, const android_dlextinfo* extinfo);
-int do_dlclose(soinfo* si);
+soinfo* do_dlopen(const char* name, int flags, soinfo* caller, const android_dlextinfo* extinfo);
+void do_dlclose(soinfo* si);
ElfW(Sym)* dlsym_linear_lookup(const char* name, soinfo** found, soinfo* start);
soinfo* find_containing_library(const void* addr);
diff --git a/tests/Android.mk b/tests/Android.mk
index 9a17c10..51f10ca 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -267,6 +267,18 @@
include $(LOCAL_PATH)/Android.build.mk
# -----------------------------------------------------------------------------
+# Library used by dlfcn tests
+# -----------------------------------------------------------------------------
+libtest_simple_src_files := \
+ dlopen_testlib_simple.cpp
+
+module := libtest_simple
+build_type := target
+build_target := SHARED_LIBRARY
+include $(LOCAL_PATH)/Android.build.mk
+
+
+# -----------------------------------------------------------------------------
# Library used by atexit tests
# -----------------------------------------------------------------------------
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 3b3c0f6..434e38f 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -50,6 +50,18 @@
ASSERT_EQ(0, dlclose(self));
}
+TEST(dlfcn, dlopen_noload) {
+ void* handle = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD);
+ ASSERT_TRUE(handle == NULL);
+ handle = dlopen("libtest_simple.so", RTLD_NOW);
+ void* handle2 = dlopen("libtest_simple.so", RTLD_NOW | RTLD_NOLOAD);
+ ASSERT_TRUE(handle != NULL);
+ ASSERT_TRUE(handle2 != NULL);
+ ASSERT_TRUE(handle == handle2);
+ ASSERT_EQ(0, dlclose(handle));
+ ASSERT_EQ(0, dlclose(handle2));
+}
+
TEST(dlfcn, dlopen_failure) {
void* self = dlopen("/does/not/exist", RTLD_NOW);
ASSERT_TRUE(self == NULL);
diff --git a/tests/dlopen_testlib_simple.cpp b/tests/dlopen_testlib_simple.cpp
new file mode 100644
index 0000000..afe54b4
--- /dev/null
+++ b/tests/dlopen_testlib_simple.cpp
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdlib.h>
+
+uint32_t dlopen_testlib_taxicab_number = 1729;
+
+bool dlopen_testlib_simple_func() {
+ return true;
+}