Merge "debuggerd: advance our amazing bet." am: 230201dcbf am: 11b938e881 am: 787f1b29d0 (85401cca) · Commits · e / os / android_system_core

adb/Android.mk

+1 −1

Original line number	Diff line number	Diff line
		@@ -343,6 +343,6 @@ LOCAL_STATIC_LIBRARIES := \
		libcrypto_utils \
		libcrypto \
		libminijail \
		libdebuggerd_client \
		libdebuggerd_handler \

		include $(BUILD_EXECUTABLE)

adb/daemon/main.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -34,9 +34,9 @@
		#include <libminijail.h>
		#include <scoped_minijail.h>

		#include "debuggerd/client.h"
		#include <private/android_filesystem_config.h>
		#include <private/android_logger.h>
		#include "debuggerd/handler.h"
		#include "selinux/android.h"

		#include "adb.h"

debuggerd/Android.bp

+192 −20

Original line number	Diff line number	Diff line
		cc_library_static {
		name: "libdebuggerd_client",
		srcs: ["client/debuggerd_client.cpp"],

		cc_defaults {
		name: "debuggerd_defaults",
		cflags: [
		"-Wall",
		"-Wextra",
		"-Werror",
		"-Wno-error",
		"-Wno-nullability-completeness",
		"-Os",
		],

		local_include_dirs: ["include"],
		}

		cc_library_static {
		name: "libdebuggerd_handler",
		defaults: ["debuggerd_defaults"],
		srcs: ["handler/debuggerd_handler.cpp"],

		// libdebuggerd_handler gets async signal safe logging via libc_logging,
		// which defines its interface in bionic private headers.
		include_dirs: ["bionic/libc"],
		static_libs: ["libc_logging"],

		export_include_dirs: ["include"],
		}

		cc_library {
		name: "libdebuggerd_client",
		defaults: ["debuggerd_defaults"],
		srcs: [
		"client/debuggerd_client.cpp",
		"util.cpp",
		],

		shared_libs: [
		"libbase",
		"libcutils",
		],
		export_include_dirs: ["include"],
		}

		cc_library {
		name: "libdebuggerd",
		defaults: ["debuggerd_defaults"],

		srcs: [
		"libdebuggerd/backtrace.cpp",
		"libdebuggerd/elf_utils.cpp",
		"libdebuggerd/open_files_list.cpp",
		"libdebuggerd/tombstone.cpp",
		"libdebuggerd/utility.cpp",
		],

		target: {
		android64: {
		cflags: ["-DTARGET_IS_64_BIT"],
		android_arm: {
		srcs: ["libdebuggerd/arm/machine.cpp"],
		},
		android_arm64: {
		srcs: ["libdebuggerd/arm64/machine.cpp"],
		},
		android_mips: {
		srcs: ["libdebuggerd/mips/machine.cpp"],
		},
		android_mips64: {
		srcs: ["libdebuggerd/mips64/machine.cpp"],
		},
		android_x86: {
		srcs: ["libdebuggerd/x86/machine.cpp"],
		},
		android_x86_64: {
		srcs: ["libdebuggerd/x86_64/machine.cpp"],
		},
		},

		local_include_dirs: ["libdebuggerd/include"],
		export_include_dirs: ["libdebuggerd/include"],

		shared_libs: [
		"libbacktrace",
		"libbase",
		"libcutils",
		"liblog",
		],
		}

		cc_test {
		name: "debuggerd_test",
		defaults: ["debuggerd_defaults"],

		cflags: ["-Wno-missing-field-initializers"],
		srcs: [
		"libdebuggerd/test/dump_memory_test.cpp",
		"libdebuggerd/test/elf_fake.cpp",
		"libdebuggerd/test/log_fake.cpp",
		"libdebuggerd/test/open_files_list_test.cpp",
		"libdebuggerd/test/property_fake.cpp",
		"libdebuggerd/test/ptrace_fake.cpp",
		"libdebuggerd/test/tombstone_test.cpp",
		],

		target: {
		android: {
		srcs: [
		"debuggerd_test.cpp",
		"util.cpp"
		],
		},
		},

		shared_libs: [
		"libbacktrace",
		"libbase",
		"libcutils",
		],

		static_libs: [
		"libdebuggerd"
		],

		local_include_dirs: [
		"libdebuggerd",
		],

		compile_multilib: "both",
		multilib: {
		lib32: {
		stem: "debuggerd_test32",
		},
		lib64: {
		stem: "debuggerd_test64",
		},
		},
		}

		cc_binary {
		name: "crash_dump",
		srcs: [
		"crash_dump.cpp",
		"util.cpp",
		],
		defaults: ["debuggerd_defaults"],

		compile_multilib: "both",
		multilib: {
		lib32: {
		suffix: "32",
		},
		lib64: {
		suffix: "64",
		},
		},

		shared_libs: [
		"libbacktrace",
		"libbase",
		"libdebuggerd",
		"liblog",
		"libprocinfo",
		"libselinux",
		],
		}

		cc_binary {
		name: "debuggerd",
		srcs: [
		"debuggerd.cpp",
		],
		defaults: ["debuggerd_defaults"],

		shared_libs: [
		"libbase",
		"libdebuggerd_client",
		"liblog",
		"libselinux",
		],

		local_include_dirs: ["include"],
		export_include_dirs: ["include"],
		}

		// libdebuggerd_client gets async signal safe logging via libc_logging,
		// which defines its interface in bionic private headers.
		include_dirs: ["bionic/libc"],
		static_libs: ["libc_logging"],
		cc_binary {
		name: "tombstoned",
		srcs: [
		"util.cpp",
		"tombstoned/intercept_manager.cpp",
		"tombstoned/tombstoned.cpp",
		],
		defaults: ["debuggerd_defaults"],

		static_libs: [
		"libbase",
		"libcutils",
		"libevent",
		"liblog",
		],

		init_rc: ["tombstoned/tombstoned.rc"]
		}

debuggerd/client/debuggerd_client.cpp

+133 −323

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2008 The Android Open Source Project
		* All rights reserved.
		* Copyright 2016, The Android Open Source Project
		*
		* 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.
		* 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
		*
		* 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.
		* 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 "debuggerd/client.h"
		#include <debuggerd/client.h>

		#include <errno.h>
		#include <inttypes.h>
		#include <pthread.h>
		#include <sched.h>
		#include <fcntl.h>
		#include <signal.h>
		#include <stddef.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>
		#include <sys/mman.h>
		#include <sys/prctl.h>
		#include <sys/socket.h>
		#include <sys/syscall.h>
		#include <sys/un.h>
		#include <sys/wait.h>
		#include <sys/stat.h>
		#include <sys/types.h>
		#include <unistd.h>

		#include "private/libc_logging.h"

		#if defined(TARGET_IS_64_BIT) && !defined(__LP64__)
		#define SOCKET_NAME "android:debuggerd32"
		#else
		#define SOCKET_NAME "android:debuggerd"
		#endif

		// see man(2) prctl, specifically the section about PR_GET_NAME
		#define MAX_TASK_NAME_LEN (16)

		static debuggerd_callbacks_t g_callbacks;
		#include <chrono>

		// Don't use __libc_fatal because it exits via abort, which might put us back into a signal handler.
		#define fatal(...) \
		do { \
		__libc_format_log(ANDROID_LOG_FATAL, "libc", __VA_ARGS__); \
		_exit(1); \
		} while (0)
		#include <android-base/logging.h>
		#include <android-base/stringprintf.h>
		#include <android-base/unique_fd.h>
		#include <cutils/sockets.h>
		#include <debuggerd/handler.h>
		#include <debuggerd/protocol.h>
		#include <debuggerd/util.h>

		static int socket_abstract_client(const char* name, int type) {
		sockaddr_un addr;
		using android::base::unique_fd;

		// Test with length +1 for the initial '\0'.
		size_t namelen = strlen(name);
		if ((namelen + 1) > sizeof(addr.sun_path)) {
		errno = EINVAL;
		return -1;
		static bool send_signal(pid_t pid, bool backtrace) {
		sigval val;
		val.sival_int = backtrace;
		if (sigqueue(pid, DEBUGGER_SIGNAL, val) != 0) {
		PLOG(ERROR) << "libdebuggerd_client: failed to send signal to pid " << pid;
		return false;
		}

		// This is used for abstract socket namespace, we need
		// an initial '\0' at the start of the Unix socket path.
		//
		// Note: The path in this case is not supposed to be
		// '\0'-terminated. ("man 7 unix" for the gory details.)
		memset(&addr, 0, sizeof(addr));
		addr.sun_family = AF_LOCAL;
		addr.sun_path[0] = 0;
		memcpy(addr.sun_path + 1, name, namelen);

		socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;

		int s = socket(AF_LOCAL, type, 0);
		if (s == -1) {
		return -1;
		return true;
		}

		int rc = TEMP_FAILURE_RETRY(connect(s, reinterpret_cast<sockaddr*>(&addr), alen));
		if (rc == -1) {
		close(s);
		return -1;
		}
		static bool check_dumpable(pid_t pid) {
		// /proc/<pid> is owned by the effective UID of the process.
		// Ownership of most of the other files in /proc/<pid> varies based on PR_SET_DUMPABLE.
		// If PR_GET_DUMPABLE would return 0, they're owned by root, instead.
		std::string proc_pid_path = android::base::StringPrintf("/proc/%d/", pid);
		std::string proc_pid_status_path = proc_pid_path + "/status";

		return s;
		unique_fd proc_pid_fd(open(proc_pid_path.c_str(), O_DIRECTORY \| O_RDONLY \| O_CLOEXEC));
		if (proc_pid_fd == -1) {
		return false;
		}

		/*
		* Writes a summary of the signal to the log file. We do this so that, if
		* for some reason we're not able to contact debuggerd, there is still some
		* indication of the failure in the log.
		*
		* We could be here as a result of native heap corruption, or while a
		* mutex is being held, so we don't want to use any libc functions that
		* could allocate memory or hold a lock.
		*/
		static void log_signal_summary(int signum, const siginfo_t* info) {
		const char* signal_name = "???";
		bool has_address = false;
		switch (signum) {
		case SIGABRT:
		signal_name = "SIGABRT";
		break;
		case SIGBUS:
		signal_name = "SIGBUS";
		has_address = true;
		break;
		case SIGFPE:
		signal_name = "SIGFPE";
		has_address = true;
		break;
		case SIGILL:
		signal_name = "SIGILL";
		has_address = true;
		break;
		case SIGSEGV:
		signal_name = "SIGSEGV";
		has_address = true;
		break;
		#if defined(SIGSTKFLT)
		case SIGSTKFLT:
		signal_name = "SIGSTKFLT";
		break;
		#endif
		case SIGSYS:
		signal_name = "SIGSYS";
		break;
		case SIGTRAP:
		signal_name = "SIGTRAP";
		break;
		unique_fd proc_pid_status_fd(openat(proc_pid_fd, "status", O_RDONLY \| O_CLOEXEC));
		if (proc_pid_status_fd == -1) {
		return false;
		}

		char thread_name[MAX_TASK_NAME_LEN + 1]; // one more for termination
		if (prctl(PR_GET_NAME, reinterpret_cast<unsigned long>(thread_name), 0, 0, 0) != 0) {
		strcpy(thread_name, "<name unknown>");
		} else {
		// short names are null terminated by prctl, but the man page
		// implies that 16 byte names are not.
		thread_name[MAX_TASK_NAME_LEN] = 0;
		struct stat proc_pid_st;
		struct stat proc_pid_status_st;
		if (fstat(proc_pid_fd.get(), &proc_pid_st) != 0 \|\|
		fstat(proc_pid_status_fd.get(), &proc_pid_status_st) != 0) {
		return false;
		}

		// "info" will be null if the siginfo_t information was not available.
		// Many signals don't have an address or a code.
		char code_desc[32]; // ", code -6"
		char addr_desc[32]; // ", fault addr 0x1234"
		addr_desc[0] = code_desc[0] = 0;
		if (info != nullptr) {
		// For a rethrown signal, this si_code will be right and the one debuggerd shows will
		// always be SI_TKILL.
		__libc_format_buffer(code_desc, sizeof(code_desc), ", code %d", info->si_code);
		if (has_address) {
		__libc_format_buffer(addr_desc, sizeof(addr_desc), ", fault addr %p", info->si_addr);
		}
		}
		__libc_format_log(ANDROID_LOG_FATAL, "libc", "Fatal signal %d (%s)%s%s in tid %d (%s)", signum,
		signal_name, code_desc, addr_desc, gettid(), thread_name);
		// We can't figure out if a process is dumpable if its effective UID is root, but that's fine
		// because being root bypasses the PR_SET_DUMPABLE check for ptrace.
		if (proc_pid_st.st_uid == 0) {
		return true;
		}

		/*
		* Returns true if the handler for signal "signum" has SA_SIGINFO set.
		*/
		static bool have_siginfo(int signum) {
		struct sigaction old_action, new_action;

		memset(&new_action, 0, sizeof(new_action));
		new_action.sa_handler = SIG_DFL;
		new_action.sa_flags = SA_RESTART;
		sigemptyset(&new_action.sa_mask);

		if (sigaction(signum, &new_action, &old_action) < 0) {
		__libc_format_log(ANDROID_LOG_WARN, "libc", "Failed testing for SA_SIGINFO: %s",
		strerror(errno));
		if (proc_pid_status_st.st_uid == 0) {
		return false;
		}
		bool result = (old_action.sa_flags & SA_SIGINFO) != 0;

		if (sigaction(signum, &old_action, nullptr) == -1) {
		__libc_format_log(ANDROID_LOG_WARN, "libc", "Restore failed in test for SA_SIGINFO: %s",
		strerror(errno));
		}
		return result;
		return true;
		}

		static void send_debuggerd_packet(pid_t crashing_tid, pid_t pseudothread_tid) {
		// Mutex to prevent multiple crashing threads from trying to talk
		// to debuggerd at the same time.
		static pthread_mutex_t crash_mutex = PTHREAD_MUTEX_INITIALIZER;
		int ret = pthread_mutex_trylock(&crash_mutex);
		if (ret != 0) {
		if (ret == EBUSY) {
		__libc_format_log(ANDROID_LOG_INFO, "libc",
		"Another thread contacted debuggerd first; not contacting debuggerd.");
		// This will never complete since the lock is never released.
		pthread_mutex_lock(&crash_mutex);
		} else {
		__libc_format_log(ANDROID_LOG_INFO, "libc", "pthread_mutex_trylock failed: %s", strerror(ret));
		}
		return;
		bool debuggerd_trigger_dump(pid_t pid, unique_fd output_fd, DebuggerdDumpType dump_type,
		int timeout_ms) {
		LOG(INFO) << "libdebuggerd_client: started dumping process " << pid;
		unique_fd sockfd;
		const auto end = std::chrono::steady_clock::now() + std::chrono::milliseconds(timeout_ms);
		auto set_timeout = [timeout_ms, &sockfd, &end]() {
		if (timeout_ms <= 0) {
		return true;
		}

		int s = socket_abstract_client(SOCKET_NAME, SOCK_STREAM \| SOCK_CLOEXEC);
		if (s == -1) {
		__libc_format_log(ANDROID_LOG_FATAL, "libc", "Unable to open connection to debuggerd: %s",
		strerror(errno));
		return;
		auto now = std::chrono::steady_clock::now();
		if (now > end) {
		return false;
		}

		// debuggerd knows our pid from the credentials on the
		// local socket but we need to tell it the tid of the crashing thread.
		// debuggerd will be paranoid and verify that we sent a tid
		// that's actually in our process.
		debugger_msg_t msg;
		msg.action = DEBUGGER_ACTION_CRASH;
		msg.tid = crashing_tid;
		msg.ignore_tid = pseudothread_tid;
		msg.abort_msg_address = 0;

		if (g_callbacks.get_abort_message) {
		msg.abort_msg_address = reinterpret_cast<uintptr_t>(g_callbacks.get_abort_message());
		}
		auto time_left = std::chrono::duration_cast<std::chrono::microseconds>(end - now);
		auto seconds = std::chrono::duration_cast<std::chrono::seconds>(time_left);
		auto microseconds = std::chrono::duration_cast<std::chrono::microseconds>(time_left - seconds);
		struct timeval timeout = {
		.tv_sec = static_cast<long>(seconds.count()),
		.tv_usec = static_cast<long>(microseconds.count()),
		};

		ret = TEMP_FAILURE_RETRY(write(s, &msg, sizeof(msg)));
		if (ret == sizeof(msg)) {
		char debuggerd_ack;
		ret = TEMP_FAILURE_RETRY(read(s, &debuggerd_ack, 1));
		if (g_callbacks.post_dump) {
		g_callbacks.post_dump();
		}
		} else {
		// read or write failed -- broken connection?
		__libc_format_log(ANDROID_LOG_FATAL, "libc", "Failed while talking to debuggerd: %s",
		strerror(errno));
		if (setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) != 0) {
		return false;
		}

		close(s);
		if (setsockopt(sockfd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout)) != 0) {
		return false;
		}

		struct debugger_thread_info {
		pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
		pid_t crashing_tid;
		pid_t pseudothread_tid;
		int signal_number;
		siginfo_t* info;
		return true;
		};

		// Logging and contacting debuggerd requires free file descriptors, which we might not have.
		// Work around this by spawning a "thread" that shares its parent's address space, but not its file
		// descriptor table, so that we can close random file descriptors without affecting the original
		// process. Note that this doesn't go through pthread_create, so TLS is shared with the spawning
		// process.
		static void* pseudothread_stack;
		static int debuggerd_dispatch_pseudothread(void* arg) {
		debugger_thread_info* thread_info = static_cast<debugger_thread_info*>(arg);

		for (int i = 3; i < 1024; ++i) {
		close(i);
		if (!check_dumpable(pid)) {
		dprintf(output_fd.get(), "target pid %d is not dumpable\n", pid);
		return true;
		}

		log_signal_summary(thread_info->signal_number, thread_info->info);
		send_debuggerd_packet(thread_info->crashing_tid, thread_info->pseudothread_tid);
		pthread_mutex_unlock(&thread_info->mutex);
		return 0;
		sockfd.reset(socket(AF_LOCAL, SOCK_SEQPACKET, 0));
		if (sockfd == -1) {
		PLOG(ERROR) << "libdebugger_client: failed to create socket";
		return false;
		}

		/*
		* Catches fatal signals so we can ask debuggerd to ptrace us before
		* we crash.
		*/
		static void debuggerd_signal_handler(int signal_number, siginfo_t* info, void*) {
		// It's possible somebody cleared the SA_SIGINFO flag, which would mean
		// our "info" arg holds an undefined value.
		if (!have_siginfo(signal_number)) {
		info = nullptr;
		if (!set_timeout()) {
		PLOG(ERROR) << "libdebugger_client: failed to set timeout";
		return false;
		}

		debugger_thread_info thread_info = {
		.crashing_tid = gettid(),
		.signal_number = signal_number,
		.info = info
		};

		pthread_mutex_lock(&thread_info.mutex);
		pid_t child_pid = clone(debuggerd_dispatch_pseudothread, pseudothread_stack,
		CLONE_THREAD \| CLONE_SIGHAND \| CLONE_VM \| CLONE_CHILD_SETTID,
		&thread_info, nullptr, nullptr, &thread_info.pseudothread_tid);

		if (child_pid == -1) {
		fatal("failed to spawn debuggerd dispatch thread: %s", strerror(errno));
		if (socket_local_client_connect(sockfd.get(), kTombstonedInterceptSocketName,
		ANDROID_SOCKET_NAMESPACE_RESERVED, SOCK_SEQPACKET) == -1) {
		PLOG(ERROR) << "libdebuggerd_client: failed to connect to tombstoned";
		return false;
		}

		// Wait for the child to finish and unlock the mutex.
		// This relies on bionic behavior that isn't guaranteed by the standard.
		pthread_mutex_lock(&thread_info.mutex);


		// We need to return from the signal handler so that debuggerd can dump the
		// thread that crashed, but returning here does not guarantee that the signal
		// will be thrown again, even for SIGSEGV and friends, since the signal could
		// have been sent manually. Resend the signal with rt_tgsigqueueinfo(2) to
		// preserve the SA_SIGINFO contents.
		signal(signal_number, SIG_DFL);

		struct siginfo si;
		if (!info) {
		memset(&si, 0, sizeof(si));
		si.si_code = SI_USER;
		si.si_pid = getpid();
		si.si_uid = getuid();
		info = &si;
		} else if (info->si_code >= 0 \|\| info->si_code == SI_TKILL) {
		// rt_tgsigqueueinfo(2)'s documentation appears to be incorrect on kernels
		// that contain commit 66dd34a (3.9+). The manpage claims to only allow
		// negative si_code values that are not SI_TKILL, but 66dd34a changed the
		// check to allow all si_code values in calls coming from inside the house.
		InterceptRequest req = {.pid = pid };
		if (!set_timeout()) {
		PLOG(ERROR) << "libdebugger_client: failed to set timeout";
		}

		int rc = syscall(SYS_rt_tgsigqueueinfo, getpid(), gettid(), signal_number, info);
		if (rc != 0) {
		fatal("failed to resend signal during crash: %s", strerror(errno));
		}
		if (send_fd(sockfd.get(), &req, sizeof(req), std::move(output_fd)) != sizeof(req)) {
		PLOG(ERROR) << "libdebuggerd_client: failed to send output fd to tombstoned";
		return false;
		}

		void debuggerd_init(debuggerd_callbacks_t* callbacks) {
		if (callbacks) {
		g_callbacks = *callbacks;
		bool backtrace = dump_type == kDebuggerdBacktrace;
		send_signal(pid, backtrace);

		if (!set_timeout()) {
		PLOG(ERROR) << "libdebugger_client: failed to set timeout";
		}

		void* thread_stack_allocation =
		mmap(nullptr, PAGE_SIZE * 3, PROT_NONE, MAP_ANONYMOUS \| MAP_PRIVATE, -1, 0);
		if (thread_stack_allocation == MAP_FAILED) {
		fatal("failed to allocate debuggerd thread stack");
		InterceptResponse response;
		ssize_t rc = TEMP_FAILURE_RETRY(recv(sockfd.get(), &response, sizeof(response), MSG_TRUNC));
		if (rc == 0) {
		LOG(ERROR) << "libdebuggerd_client: failed to read response from tombstoned: timeout reached?";
		return false;
		} else if (rc != sizeof(response)) {
		LOG(ERROR)
		<< "libdebuggerd_client: received packet of unexpected length from tombstoned: expected "
		<< sizeof(response) << ", received " << rc;
		return false;
		}

		char* stack = static_cast<char*>(thread_stack_allocation) + PAGE_SIZE;
		if (mprotect(stack, PAGE_SIZE, PROT_READ \| PROT_WRITE) != 0) {
		fatal("failed to mprotect debuggerd thread stack");
		if (response.success != 1) {
		response.error_message[sizeof(response.error_message) - 1] = '\0';
		LOG(ERROR) << "libdebuggerd_client: tombstoned reported failure: " << response.error_message;
		}

		// Stack grows negatively, set it to the last byte in the page...
		stack = (stack + PAGE_SIZE - 1);
		// and align it.
		stack -= 15;
		pseudothread_stack = stack;
		LOG(INFO) << "libdebuggerd_client: done dumping process " << pid;

		struct sigaction action;
		memset(&action, 0, sizeof(action));
		sigemptyset(&action.sa_mask);
		action.sa_sigaction = debuggerd_signal_handler;
		action.sa_flags = SA_RESTART \| SA_SIGINFO;
		return true;
		}

		// Use the alternate signal stack if available so we can catch stack overflows.
		action.sa_flags \|= SA_ONSTACK;
		int dump_backtrace_to_file(pid_t tid, int fd) {
		return dump_backtrace_to_file_timeout(tid, fd, 0);
		}

		sigaction(SIGABRT, &action, nullptr);
		sigaction(SIGBUS, &action, nullptr);
		sigaction(SIGFPE, &action, nullptr);
		sigaction(SIGILL, &action, nullptr);
		sigaction(SIGSEGV, &action, nullptr);
		#if defined(SIGSTKFLT)
		sigaction(SIGSTKFLT, &action, nullptr);
		#endif
		sigaction(SIGTRAP, &action, nullptr);
		int dump_backtrace_to_file_timeout(pid_t tid, int fd, int timeout_secs) {
		android::base::unique_fd copy(dup(fd));
		if (copy == -1) {
		return -1;
		}
		int timeout_ms = timeout_secs > 0 ? timeout_secs * 1000 : 0;
		return debuggerd_trigger_dump(tid, std::move(copy), kDebuggerdBacktrace, timeout_ms) ? 0 : -1;
		}

debuggerd/crash_dump.cpp

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+388 −0

File added.

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