Add tests for elf unwinding in memory.
Bug: 19517541
Change-Id: Ib42360a82934ff7103e2ccb64c1105c59aa3fdea
diff --git a/libbacktrace/Android.mk b/libbacktrace/Android.mk
index a2b4cfe..be8b803 100644
--- a/libbacktrace/Android.mk
+++ b/libbacktrace/Android.mk
@@ -110,12 +110,14 @@
backtrace_test_shared_libraries := \
libbacktrace_test \
libbacktrace \
-
-backtrace_test_shared_libraries_target := \
+ libbase \
libcutils \
-backtrace_test_static_libraries_host := \
- libcutils \
+backtrace_test_shared_libraries_target += \
+ libdl \
+
+backtrace_test_ldlibs_host += \
+ -ldl \
module := backtrace_test
module_tag := debug
diff --git a/libbacktrace/backtrace_test.cpp b/libbacktrace/backtrace_test.cpp
index a086547..760f5cc 100644
--- a/libbacktrace/backtrace_test.cpp
+++ b/libbacktrace/backtrace_test.cpp
@@ -16,7 +16,9 @@
#define _GNU_SOURCE 1
#include <dirent.h>
+#include <dlfcn.h>
#include <errno.h>
+#include <fcntl.h>
#include <inttypes.h>
#include <pthread.h>
#include <signal.h>
@@ -25,12 +27,14 @@
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
+#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <algorithm>
+#include <list>
#include <memory>
#include <string>
#include <vector>
@@ -38,6 +42,7 @@
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
+#include <base/stringprintf.h>
#include <cutils/atomic.h>
#include <cutils/threads.h>
@@ -1023,6 +1028,7 @@
}
TEST(libbacktrace, process_read) {
+ g_ready = 0;
pid_t pid;
if ((pid = fork()) == 0) {
ForkedReadTest();
@@ -1069,6 +1075,297 @@
ASSERT_TRUE(test_executed);
}
+void VerifyFunctionsFound(const std::vector<std::string>& found_functions) {
+ // We expect to find these functions in libbacktrace_test. If we don't
+ // find them, that's a bug in the memory read handling code in libunwind.
+ std::list<std::string> expected_functions;
+ expected_functions.push_back("test_recursive_call");
+ expected_functions.push_back("test_level_one");
+ expected_functions.push_back("test_level_two");
+ expected_functions.push_back("test_level_three");
+ expected_functions.push_back("test_level_four");
+ for (const auto& found_function : found_functions) {
+ for (const auto& expected_function : expected_functions) {
+ if (found_function == expected_function) {
+ expected_functions.remove(found_function);
+ break;
+ }
+ }
+ }
+ ASSERT_TRUE(expected_functions.empty()) << "Not all functions found in shared library.";
+}
+
+const char* CopySharedLibrary() {
+#if defined(__LP64__)
+ const char* lib_name = "lib64";
+#else
+ const char* lib_name = "lib";
+#endif
+
+#if defined(__BIONIC__)
+ const char* tmp_so_name = "/data/local/tmp/libbacktrace_test.so";
+ std::string cp_cmd = android::base::StringPrintf("cp /system/%s/libbacktrace_test.so %s",
+ lib_name, tmp_so_name);
+#else
+ const char* tmp_so_name = "/tmp/libbacktrace_test.so";
+ if (getenv("ANDROID_HOST_OUT") == NULL) {
+ fprintf(stderr, "ANDROID_HOST_OUT not set, make sure you run lunch.");
+ return nullptr;
+ }
+ std::string cp_cmd = android::base::StringPrintf("cp %s/%s/libbacktrace_test.so %s",
+ getenv("ANDROID_HOST_OUT"), lib_name,
+ tmp_so_name);
+#endif
+
+ // Copy the shared so to a tempory directory.
+ system(cp_cmd.c_str());
+
+ return tmp_so_name;
+}
+
+TEST(libbacktrace, check_unreadable_elf_local) {
+ const char* tmp_so_name = CopySharedLibrary();
+ ASSERT_TRUE(tmp_so_name != nullptr);
+
+ struct stat buf;
+ ASSERT_TRUE(stat(tmp_so_name, &buf) != -1);
+ uintptr_t map_size = buf.st_size;
+
+ int fd = open(tmp_so_name, O_RDONLY);
+ ASSERT_TRUE(fd != -1);
+
+ void* map = mmap(NULL, map_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ ASSERT_TRUE(map != MAP_FAILED);
+ close(fd);
+ ASSERT_TRUE(unlink(tmp_so_name) != -1);
+
+ std::vector<std::string> found_functions;
+ std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS,
+ BACKTRACE_CURRENT_THREAD));
+ ASSERT_TRUE(backtrace.get() != nullptr);
+
+ // Needed before GetFunctionName will work.
+ backtrace->Unwind(0);
+
+ // Loop through the entire map, and get every function we can find.
+ map_size += reinterpret_cast<uintptr_t>(map);
+ std::string last_func;
+ for (uintptr_t read_addr = reinterpret_cast<uintptr_t>(map);
+ read_addr < map_size; read_addr += 4) {
+ uintptr_t offset;
+ std::string func_name = backtrace->GetFunctionName(read_addr, &offset);
+ if (!func_name.empty() && last_func != func_name) {
+ found_functions.push_back(func_name);
+ }
+ last_func = func_name;
+ }
+
+ ASSERT_TRUE(munmap(map, map_size - reinterpret_cast<uintptr_t>(map)) == 0);
+
+ VerifyFunctionsFound(found_functions);
+}
+
+TEST(libbacktrace, check_unreadable_elf_remote) {
+ const char* tmp_so_name = CopySharedLibrary();
+ ASSERT_TRUE(tmp_so_name != nullptr);
+
+ g_ready = 0;
+
+ struct stat buf;
+ ASSERT_TRUE(stat(tmp_so_name, &buf) != -1);
+ uintptr_t map_size = buf.st_size;
+
+ pid_t pid;
+ if ((pid = fork()) == 0) {
+ int fd = open(tmp_so_name, O_RDONLY);
+ if (fd == -1) {
+ fprintf(stderr, "Failed to open file %s: %s\n", tmp_so_name, strerror(errno));
+ unlink(tmp_so_name);
+ exit(0);
+ }
+
+ void* map = mmap(NULL, map_size, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (map == MAP_FAILED) {
+ fprintf(stderr, "Failed to map in memory: %s\n", strerror(errno));
+ unlink(tmp_so_name);
+ exit(0);
+ }
+ close(fd);
+ if (unlink(tmp_so_name) == -1) {
+ fprintf(stderr, "Failed to unlink: %s\n", strerror(errno));
+ exit(0);
+ }
+
+ g_addr = reinterpret_cast<uintptr_t>(map);
+ g_ready = 1;
+ while (true) {
+ usleep(US_PER_MSEC);
+ }
+ exit(0);
+ }
+ ASSERT_TRUE(pid > 0);
+
+ std::vector<std::string> found_functions;
+ uint64_t start = NanoTime();
+ while (true) {
+ ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
+
+ // Wait for the process to get to a stopping point.
+ WaitForStop(pid);
+
+ std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, BACKTRACE_CURRENT_THREAD));
+ ASSERT_TRUE(backtrace.get() != nullptr);
+
+ uintptr_t read_addr;
+ ASSERT_EQ(sizeof(uintptr_t), backtrace->Read(reinterpret_cast<uintptr_t>(&g_ready), reinterpret_cast<uint8_t*>(&read_addr), sizeof(uintptr_t)));
+ if (read_addr) {
+ ASSERT_EQ(sizeof(uintptr_t), backtrace->Read(reinterpret_cast<uintptr_t>(&g_addr), reinterpret_cast<uint8_t*>(&read_addr), sizeof(uintptr_t)));
+
+ // Needed before GetFunctionName will work.
+ backtrace->Unwind(0);
+
+ // Loop through the entire map, and get every function we can find.
+ map_size += read_addr;
+ std::string last_func;
+ for (; read_addr < map_size; read_addr += 4) {
+ uintptr_t offset;
+ std::string func_name = backtrace->GetFunctionName(read_addr, &offset);
+ if (!func_name.empty() && last_func != func_name) {
+ found_functions.push_back(func_name);
+ }
+ last_func = func_name;
+ }
+ break;
+ }
+ ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
+
+ if ((NanoTime() - start) > 5 * NS_PER_SEC) {
+ break;
+ }
+ usleep(US_PER_MSEC);
+ }
+
+ kill(pid, SIGKILL);
+ ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
+
+ VerifyFunctionsFound(found_functions);
+}
+
+bool FindFuncFrameInBacktrace(Backtrace* backtrace, uintptr_t test_func, size_t* frame_num) {
+ backtrace_map_t map;
+ backtrace->FillInMap(test_func, &map);
+ if (!BacktraceMap::IsValid(map)) {
+ return false;
+ }
+
+ // Loop through the frames, and find the one that is in the map.
+ *frame_num = 0;
+ for (Backtrace::const_iterator it = backtrace->begin(); it != backtrace->end(); ++it) {
+ if (BacktraceMap::IsValid(it->map) && map.start == it->map.start &&
+ it->pc >= test_func) {
+ *frame_num = it->num;
+ return true;
+ }
+ }
+ return false;
+}
+
+void VerifyUnreadableElfFrame(Backtrace* backtrace, uintptr_t test_func, size_t frame_num) {
+ ASSERT_LT(backtrace->NumFrames(), static_cast<size_t>(MAX_BACKTRACE_FRAMES))
+ << DumpFrames(backtrace);
+
+ ASSERT_TRUE(frame_num != 0) << DumpFrames(backtrace);
+ // Make sure that there is at least one more frame above the test func call.
+ ASSERT_LT(frame_num, backtrace->NumFrames()) << DumpFrames(backtrace);
+
+ uintptr_t diff = backtrace->GetFrame(frame_num)->pc - test_func;
+ ASSERT_LT(diff, 200U) << DumpFrames(backtrace);
+}
+
+void VerifyUnreadableElfBacktrace(uintptr_t test_func) {
+ std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS,
+ BACKTRACE_CURRENT_THREAD));
+ ASSERT_TRUE(backtrace.get() != nullptr);
+ ASSERT_TRUE(backtrace->Unwind(0));
+
+ size_t frame_num;
+ ASSERT_TRUE(FindFuncFrameInBacktrace(backtrace.get(), test_func, &frame_num));
+
+ VerifyUnreadableElfFrame(backtrace.get(), test_func, frame_num);
+}
+
+typedef int (*test_func_t)(int, int, int, int, void (*)(uintptr_t), uintptr_t);
+
+TEST(libbacktrace, unwind_through_unreadable_elf_local) {
+ const char* tmp_so_name = CopySharedLibrary();
+ ASSERT_TRUE(tmp_so_name != nullptr);
+ void* lib_handle = dlopen(tmp_so_name, RTLD_NOW);
+ ASSERT_TRUE(lib_handle != nullptr);
+ ASSERT_TRUE(unlink(tmp_so_name) != -1);
+
+ test_func_t test_func;
+ test_func = reinterpret_cast<test_func_t>(dlsym(lib_handle, "test_level_one"));
+ ASSERT_TRUE(test_func != nullptr);
+
+ ASSERT_NE(test_func(1, 2, 3, 4, VerifyUnreadableElfBacktrace,
+ reinterpret_cast<uintptr_t>(test_func)), 0);
+
+ ASSERT_TRUE(dlclose(lib_handle) == 0);
+}
+
+TEST(libbacktrace, unwind_through_unreadable_elf_remote) {
+ const char* tmp_so_name = CopySharedLibrary();
+ ASSERT_TRUE(tmp_so_name != nullptr);
+ void* lib_handle = dlopen(tmp_so_name, RTLD_NOW);
+ ASSERT_TRUE(lib_handle != nullptr);
+ ASSERT_TRUE(unlink(tmp_so_name) != -1);
+
+ test_func_t test_func;
+ test_func = reinterpret_cast<test_func_t>(dlsym(lib_handle, "test_level_one"));
+ ASSERT_TRUE(test_func != nullptr);
+
+ pid_t pid;
+ if ((pid = fork()) == 0) {
+ test_func(1, 2, 3, 4, 0, 0);
+ exit(0);
+ }
+ ASSERT_TRUE(pid > 0);
+ ASSERT_TRUE(dlclose(lib_handle) == 0);
+
+ uint64_t start = NanoTime();
+ bool done = false;
+ while (!done) {
+ ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
+
+ // Wait for the process to get to a stopping point.
+ WaitForStop(pid);
+
+ std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, BACKTRACE_CURRENT_THREAD));
+ ASSERT_TRUE(backtrace.get() != nullptr);
+ ASSERT_TRUE(backtrace->Unwind(0));
+
+ size_t frame_num;
+ if (FindFuncFrameInBacktrace(backtrace.get(),
+ reinterpret_cast<uintptr_t>(test_func), &frame_num)) {
+
+ VerifyUnreadableElfFrame(backtrace.get(), reinterpret_cast<uintptr_t>(test_func), frame_num);
+ done = true;
+ }
+
+ ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
+
+ if ((NanoTime() - start) > 5 * NS_PER_SEC) {
+ break;
+ }
+ usleep(US_PER_MSEC);
+ }
+
+ kill(pid, SIGKILL);
+ ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
+
+ ASSERT_TRUE(done) << "Test function never found in unwind.";
+}
+
#if defined(ENABLE_PSS_TESTS)
#include "GetPss.h"
@@ -1142,3 +1439,4 @@
ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
}
#endif
+