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; +}