From 98731dc343c347cf7db75125abb560687543cd22 Mon Sep 17 00:00:00 2001 From: Ryan Prichard Date: Thu, 29 Feb 2024 22:56:36 -0800 Subject: [PATCH] Revamp the elftls_dl.dtv_resize test Split the test out into a separate executable to reduce the number of ELF modules in the DTV, so that the test can more easily observe the behavior of loading a module that requires doubling the DTV size. We want to see the DTV expand from 5 entries (8 words w/header) to 13 entries (16 words w/header). Make the test work with an initial number of ELF TLS modules between 2 and 4. Bug: http://b/175635923 Test: bionic-unit-tests Change-Id: I1e91b4462987a5c80e13838669c359053f5a62f6 --- tests/Android.bp | 3 + tests/elftls_dl_test.cpp | 73 +------- tests/libs/Android.bp | 33 ++++ tests/libs/elftls_dtv_resize_helper.cpp | 224 ++++++++++++++++++++++++ 4 files changed, 266 insertions(+), 67 deletions(-) create mode 100644 tests/libs/elftls_dtv_resize_helper.cpp diff --git a/tests/Android.bp b/tests/Android.bp index 4e9192e85..89d226772 100644 --- a/tests/Android.bp +++ b/tests/Android.bp @@ -835,6 +835,7 @@ cc_defaults { "cfi_test_helper", "cfi_test_helper2", "elftls_dlopen_ie_error_helper", + "elftls_dtv_resize_helper", "exec_linker_helper", "exec_linker_helper_lib", "heap_tagging_async_helper", @@ -937,6 +938,8 @@ cc_defaults { "libtest_elftls_dynamic_filler_1", "libtest_elftls_dynamic_filler_2", "libtest_elftls_dynamic_filler_3", + "libtest_elftls_dynamic_filler_4", + "libtest_elftls_dynamic_filler_5", "libtest_elftls_shared_var", "libtest_elftls_shared_var_ie", "libtest_elftls_tprel", diff --git a/tests/elftls_dl_test.cpp b/tests/elftls_dl_test.cpp index e2fa3a087..bcb2b40b3 100644 --- a/tests/elftls_dl_test.cpp +++ b/tests/elftls_dl_test.cpp @@ -29,10 +29,9 @@ #include #include -#include -#include #include +#include #include #include "gtest_globals.h" @@ -155,71 +154,11 @@ TEST(elftls_dl, tlsdesc_missing_weak) { TEST(elftls_dl, dtv_resize) { #if defined(__BIONIC__) -#define LOAD_LIB(soname) ({ \ - auto lib = dlopen(soname, RTLD_LOCAL | RTLD_NOW); \ - ASSERT_NE(nullptr, lib); \ - reinterpret_cast(dlsym(lib, "bump")); \ - }) - - auto dtv = []() -> TlsDtv* { return __get_tcb_dtv(__get_bionic_tcb()); }; - - static_assert(sizeof(TlsDtv) == 3 * sizeof(void*), - "This test assumes that the Dtv has a 3-word header"); - - // Initially there are 4 modules (5 w/ hwasan): - // - the main test executable - // - libc - // - libtest_elftls_shared_var - // - libtest_elftls_tprel - // - w/ hwasan: libclang_rt.hwasan - - // The initial DTV is an empty DTV with no generation and a size of 0. - TlsDtv* zero_dtv = dtv(); - ASSERT_EQ(0u, zero_dtv->count); - ASSERT_EQ(nullptr, zero_dtv->next); - ASSERT_EQ(kTlsGenerationNone, zero_dtv->generation); - - // Load module 5 (6 w/ hwasan). - auto func1 = LOAD_LIB("libtest_elftls_dynamic_filler_1.so"); - ASSERT_EQ(101, func1()); - - // After loading one module, the DTV should be initialized to the next - // power-of-2 size (including the header). - TlsDtv* initial_dtv = dtv(); - ASSERT_EQ(running_with_hwasan() ? 13u : 5u, dtv()->count); - ASSERT_EQ(zero_dtv, initial_dtv->next); - ASSERT_LT(0u, initial_dtv->generation); - - // Load module 6 (7 w/ hwasan). - auto func2 = LOAD_LIB("libtest_elftls_dynamic_filler_2.so"); - ASSERT_EQ(102, func1()); - -#if defined(__aarch64__) - // The arm64 TLSDESC resolver doesn't update the DTV if it is new enough for - // the given access. - ASSERT_EQ(running_with_hwasan() ? 13u : 5u, dtv()->count); -#else - // __tls_get_addr updates the DTV anytime the generation counter changes. - ASSERT_EQ(13u, dtv()->count); -#endif - - ASSERT_EQ(201, func2()); - TlsDtv* new_dtv = dtv(); - if (!running_with_hwasan()) { - ASSERT_NE(initial_dtv, new_dtv); - ASSERT_EQ(initial_dtv, new_dtv->next); - } - ASSERT_EQ(13u, new_dtv->count); - - // Load module 7 (8 w/ hwasan). - auto func3 = LOAD_LIB("libtest_elftls_dynamic_filler_3.so"); - ASSERT_EQ(103, func1()); - ASSERT_EQ(202, func2()); - ASSERT_EQ(301, func3()); - - ASSERT_EQ(new_dtv, dtv()); - -#undef LOAD_LIB + std::string helper = GetTestlibRoot() + "/elftls_dtv_resize_helper"; + chmod(helper.c_str(), 0755); // TODO: "x" lost in CTS, b/34945607 + ExecTestHelper eth; + eth.SetArgs({helper.c_str(), nullptr}); + eth.Run([&]() { execve(helper.c_str(), eth.GetArgs(), eth.GetEnv()); }, 0, nullptr); #else GTEST_SKIP() << "test doesn't apply to glibc"; #endif diff --git a/tests/libs/Android.bp b/tests/libs/Android.bp index 06ee132d4..f64055213 100644 --- a/tests/libs/Android.bp +++ b/tests/libs/Android.bp @@ -123,6 +123,39 @@ cc_test_library { ], } +cc_test_library { + name: "libtest_elftls_dynamic_filler_4", + defaults: ["bionic_testlib_defaults"], + srcs: ["elftls_dynamic_filler.cpp"], + cflags: [ + "-DTLS_FILLER=400", + ], +} + +cc_test_library { + name: "libtest_elftls_dynamic_filler_5", + defaults: ["bionic_testlib_defaults"], + srcs: ["elftls_dynamic_filler.cpp"], + cflags: [ + "-DTLS_FILLER=500", + ], +} + +cc_test { + name: "elftls_dtv_resize_helper", + defaults: [ + "bionic_testlib_defaults", + "bionic_targets_only", + ], + srcs: ["elftls_dtv_resize_helper.cpp"], + include_dirs: [ + "bionic/libc", + ], + static_libs: [ + "libbase", + ], +} + // ----------------------------------------------------------------------------- // Library to test gnu-styled hash // ----------------------------------------------------------------------------- diff --git a/tests/libs/elftls_dtv_resize_helper.cpp b/tests/libs/elftls_dtv_resize_helper.cpp new file mode 100644 index 000000000..125f8e84f --- /dev/null +++ b/tests/libs/elftls_dtv_resize_helper.cpp @@ -0,0 +1,224 @@ +/* + * Copyright (C) 2024 The Android Open Source Project + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, + * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT + * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include +#include +#include + +#include +#include + +#include + +#include "bionic/pthread_internal.h" + +constexpr bool kDumpModulesForDebugging = false; + +// The old external/libcxx doesn't have operator<< for nullptr. +// TODO(b/175635923): Remove this hack after upgrading libc++. +template +T fix_nullptr(T&& arg) { + return arg; +} +void* fix_nullptr(nullptr_t arg) { + return static_cast(arg); +} + +template +void check(int line, const char* val1_expr, Val1&& val1, const char* val2_expr, Val2&& val2, + Compare compare) { + if (!compare(val1, val2)) { + std::cerr << __FILE__ << ":" << line << ": assertion failed: LHS(" << val1_expr << ") is " + << fix_nullptr(val1) << ", RHS(" << val2_expr << ") is " << fix_nullptr(val2) << "\n" + << std::flush; + abort(); + } +} + +#define ASSERT_EQ(val1, val2) check(__LINE__, #val1, val1, #val2, val2, std::equal_to()) +#define ASSERT_NE(val1, val2) check(__LINE__, #val1, val1, #val2, val2, std::not_equal_to()) +#define ASSERT_LT(val1, val2) check(__LINE__, #val1, val1, #val2, val2, std::less()) +#define ASSERT_LE(val1, val2) check(__LINE__, #val1, val1, #val2, val2, std::less_equal()) + +static size_t highest_loaded_modid() { + size_t result = 0; + auto update_result = [](struct dl_phdr_info* info, size_t size __unused, void* data) { + size_t& result = *reinterpret_cast(data); + if (kDumpModulesForDebugging) { + fprintf(stderr, "module %s: TLS modid %zu\n", info->dlpi_name, info->dlpi_tls_modid); + } + result = std::max(result, info->dlpi_tls_modid); + return 0; + }; + dl_iterate_phdr(update_result, &result); + return result; +} + +static TlsDtv* dtv() { + return __get_tcb_dtv(__get_bionic_tcb()); +} + +static size_t highest_modid_in_dtv() { + TlsDtv* current_dtv = dtv(); + size_t result = 0; + for (size_t i = 0; i < current_dtv->count; ++i) { + if (current_dtv->modules[i] != nullptr) { + result = __tls_module_idx_to_id(i); + } + } + return result; +} + +// Unused, but ensures that the test executable has a TLS segment. With a +// new-enough libc++_static.a, the test executable will tend to has a TLS +// segment to hold the libc++ EH globals pointer. +__thread int g_tls_var_placeholder = 42; + +int main() { + // Prevent this TLS variable from being optimized away. + ASSERT_EQ(42, g_tls_var_placeholder); + + auto load_lib = [](const char* soname) { + void* lib = dlopen(soname, RTLD_LOCAL | RTLD_NOW); + ASSERT_NE(nullptr, lib); + auto func = reinterpret_cast(dlsym(lib, "bump")); + ASSERT_NE(nullptr, func); + return func; + }; + + static_assert(sizeof(TlsDtv) == 3 * sizeof(void*), + "This test assumes that the Dtv has a 3-word header"); + + // Initially there are 2-4 modules: + // - 1: test executable + // - 2: libc + // - 3: libc++ (when using a new-enough libc++) + // - 4: libclang_rt.hwasan (when running with HWASan) + size_t first_filler_modid = highest_loaded_modid() + 1; + ASSERT_LE(2, highest_loaded_modid()); + ASSERT_LE(highest_loaded_modid(), 4); + + // The initial DTV is an empty DTV with no generation and a size of 0. + TlsDtv* zero_dtv = dtv(); + ASSERT_EQ(0u, zero_dtv->count); + ASSERT_EQ(nullptr, zero_dtv->next); + ASSERT_EQ(kTlsGenerationNone, zero_dtv->generation); + + // Load a module. The DTV is still empty unless the TLS variable is accessed. + auto func1 = load_lib("libtest_elftls_dynamic_filler_1.so"); + ASSERT_EQ(zero_dtv, dtv()); + ASSERT_EQ(first_filler_modid, highest_loaded_modid()); + + // After accessing a TLS variable, the DTV should be initialized. It should be + // 8 words in size, with a 5-entry capacity. + ASSERT_EQ(101, func1()); + TlsDtv* initial_dtv = dtv(); + ASSERT_EQ(5u, dtv()->count); + ASSERT_EQ(zero_dtv, initial_dtv->next); + ASSERT_LT(0u, initial_dtv->generation); + ASSERT_EQ(first_filler_modid, highest_modid_in_dtv()); + ASSERT_NE(nullptr, initial_dtv->modules[__tls_module_id_to_idx(first_filler_modid)]); + + size_t current_generation = initial_dtv->generation; + + // Fill the rest of the DTV up. (i.e. Ensure that exactly 5 modules with TLS + // segments are loaded.) + auto fill_entry = [&](size_t modid, const char* soname, int tls_var_value) { + if (highest_modid_in_dtv() == modid - 1) { + auto func = load_lib(soname); + + // Loading the module doesn't affect the DTV yet. + ASSERT_EQ(initial_dtv, dtv()); + ASSERT_EQ(modid, highest_loaded_modid()); + ASSERT_EQ(modid - 1, highest_modid_in_dtv()); + ASSERT_EQ(current_generation, initial_dtv->generation); + + // Access the TLS variable, which will allocate it in the DTV. + ASSERT_EQ(tls_var_value, func()); + + // Verify allocation and a bumped generation. + ASSERT_EQ(initial_dtv, dtv()); + ASSERT_EQ(modid, highest_modid_in_dtv()); + ASSERT_LT(current_generation, initial_dtv->generation); + current_generation = initial_dtv->generation; + } + }; + + fill_entry(4u, "libtest_elftls_dynamic_filler_2.so", 201); + fill_entry(5u, "libtest_elftls_dynamic_filler_3.so", 301); + ASSERT_EQ(5u, highest_modid_in_dtv()); + + // Load module 6, which will require doubling the size of the DTV. + auto func4 = load_lib("libtest_elftls_dynamic_filler_4.so"); + ASSERT_EQ(6u, highest_loaded_modid()); + ASSERT_EQ(5u, highest_modid_in_dtv()); + ASSERT_EQ(initial_dtv, dtv()); + + // Access a TLS variable from the first filler module. + ASSERT_EQ(102, func1()); + ASSERT_EQ(5u, highest_modid_in_dtv()); +#if defined(__aarch64__) + // The arm64 TLSDESC resolver doesn't update the DTV if it is new enough for + // the given access. + ASSERT_EQ(initial_dtv, dtv()); + ASSERT_EQ(5u, dtv()->count); + ASSERT_EQ(current_generation, dtv()->generation); +#else + // __tls_get_addr updates the DTV anytime the generation counter changes, but + // the highest modid in the DTV is still 5, because module 6 hasn't been + // allocated yet. + ASSERT_NE(initial_dtv, dtv()); + ASSERT_EQ(13u, dtv()->count); + ASSERT_LT(current_generation, dtv()->generation); +#endif + + // Accessing the TLS variable in the latest module will always expand the DTV. + ASSERT_EQ(401, func4()); + TlsDtv* new_dtv = dtv(); + ASSERT_NE(initial_dtv, new_dtv); + ASSERT_EQ(initial_dtv, new_dtv->next); + ASSERT_EQ(13u, new_dtv->count); + ASSERT_LT(current_generation, new_dtv->generation); + ASSERT_EQ(6u, highest_modid_in_dtv()); + current_generation = new_dtv->generation; + + // Load one more filler, module 7. + auto func5 = load_lib("libtest_elftls_dynamic_filler_5.so"); + ASSERT_EQ(103, func1()); + ASSERT_EQ(402, func4()); + ASSERT_EQ(6u, highest_modid_in_dtv()); + ASSERT_EQ(501, func5()); + ASSERT_EQ(7u, highest_modid_in_dtv()); + + // Verify that no new DTV has been allocated. + ASSERT_EQ(new_dtv, dtv()); + ASSERT_EQ(13u, new_dtv->count); + ASSERT_LT(current_generation, new_dtv->generation); + + return 0; +}