debuggerd: add libdebuggerd_client. (9c02dc59) · Commits · e / os / android_system_core

debuggerd/Android.bp

0 → 100644

+19 −0

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

		cflags: [
		"-Wall",
		"-Wextra",
		"-Werror",
		"-Os",
		],

		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"],
		}

debuggerd/Android.mk→debuggerd/Android.soong.mk

+35 −7

Original line number	Diff line number	Diff line
		@@ -8,6 +8,10 @@ common_cppflags := \
		-Wunused \
		-Werror \

		ifeq ($(TARGET_IS_64_BIT),true)
		common_cppflags += -DTARGET_IS_64_BIT
		endif

		include $(CLEAR_VARS)

		LOCAL_SRC_FILES:= \
		@@ -26,15 +30,12 @@ LOCAL_SRC_FILES_mips64 := mips64/machine.cpp
		LOCAL_SRC_FILES_x86 := x86/machine.cpp
		LOCAL_SRC_FILES_x86_64 := x86_64/machine.cpp

		LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
		LOCAL_CPPFLAGS := $(common_cppflags)

		LOCAL_INIT_RC_32 := debuggerd.rc
		LOCAL_INIT_RC_64 := debuggerd64.rc

		ifeq ($(TARGET_IS_64_BIT),true)
		LOCAL_CPPFLAGS += -DTARGET_IS_64_BIT
		endif

		LOCAL_SHARED_LIBRARIES := \
		libbacktrace \
		libbase \
		@@ -51,7 +52,7 @@ LOCAL_MULTILIB := both

		include $(BUILD_EXECUTABLE)


		crasher_cppflags := $(common_cppflags) -fstack-protector-all -Wno-free-nonheap-object -Wno-date-time

		include $(CLEAR_VARS)
		LOCAL_SRC_FILES := crasher.cpp
		@@ -63,8 +64,7 @@ LOCAL_SRC_FILES_x86 := x86/crashglue.S
		LOCAL_SRC_FILES_x86_64 := x86_64/crashglue.S
		LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
		LOCAL_MODULE_TAGS := optional
		LOCAL_CPPFLAGS := $(common_cppflags) -fstack-protector-all -Wno-free-nonheap-object -Wno-date-time
		#LOCAL_FORCE_STATIC_EXECUTABLE := true
		LOCAL_CPPFLAGS := $(crasher_cppflags)
		LOCAL_SHARED_LIBRARIES := libcutils liblog

		# The arm emulator has VFP but not VFPv3-D32.
		@@ -79,6 +79,34 @@ LOCAL_MULTILIB := both

		include $(BUILD_EXECUTABLE)

		include $(CLEAR_VARS)
		LOCAL_SRC_FILES := crasher.cpp
		LOCAL_SRC_FILES_arm := arm/crashglue.S
		LOCAL_SRC_FILES_arm64 := arm64/crashglue.S
		LOCAL_SRC_FILES_mips := mips/crashglue.S
		LOCAL_SRC_FILES_mips64 := mips64/crashglue.S
		LOCAL_SRC_FILES_x86 := x86/crashglue.S
		LOCAL_SRC_FILES_x86_64 := x86_64/crashglue.S
		LOCAL_MODULE_PATH := $(TARGET_OUT_OPTIONAL_EXECUTABLES)
		LOCAL_MODULE_TAGS := optional
		LOCAL_CPPFLAGS := $(crasher_cppflags) -DSTATIC_CRASHER
		LOCAL_FORCE_STATIC_EXECUTABLE := true
		LOCAL_SHARED_LIBRARIES := libcutils liblog

		# The arm emulator has VFP but not VFPv3-D32.
		ifeq ($(ARCH_ARM_HAVE_VFP_D32),true)
		LOCAL_ASFLAGS_arm += -DHAS_VFP_D32
		endif

		LOCAL_MODULE := static_crasher
		LOCAL_MODULE_STEM_32 := static_crasher
		LOCAL_MODULE_STEM_64 := static_crasher64
		LOCAL_MULTILIB := both

		LOCAL_STATIC_LIBRARIES := libdebuggerd_client libcutils liblog

		include $(BUILD_EXECUTABLE)

		debuggerd_test_src_files := \
		utility.cpp \
		test/dump_memory_test.cpp \

debuggerd/client/debuggerd_client.cpp

0 → 100644

+311 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2008 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 "debuggerd/client.h"

		#include <errno.h>
		#include <inttypes.h>
		#include <pthread.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 <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;

		static int socket_abstract_client(const char* name, int type) {
		sockaddr_un addr;

		// Test with length +1 for the initial '\0'.
		size_t namelen = strlen(name);
		if ((namelen + 1) > sizeof(addr.sun_path)) {
		errno = EINVAL;
		return -1;
		}

		// 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;
		}

		int rc = TEMP_FAILURE_RETRY(connect(s, reinterpret_cast<sockaddr*>(&addr), alen));
		if (rc == -1) {
		close(s);
		return -1;
		}

		return s;
		}

		/*
		* 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 SIGTRAP:
		signal_name = "SIGTRAP";
		break;
		}

		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;
		}

		// "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);
		}

		/*
		* 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));
		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;
		}

		static void send_debuggerd_packet(siginfo_t* info) {
		// 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;
		}

		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;
		}

		// 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 = gettid();
		msg.abort_msg_address = 0;

		if (g_callbacks.get_abort_message) {
		msg.abort_msg_address = reinterpret_cast<uintptr_t>(g_callbacks.get_abort_message());
		}

		msg.original_si_code = (info != nullptr) ? info->si_code : 0;
		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));
		int saved_errno = errno;
		if (g_callbacks.post_dump) {
		g_callbacks.post_dump();
		}
		errno = saved_errno;
		} else {
		// read or write failed -- broken connection?
		__libc_format_log(ANDROID_LOG_FATAL, "libc", "Failed while talking to debuggerd: %s",
		strerror(errno));
		}

		close(s);
		}

		/*
		* 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;
		}

		log_signal_summary(signal_number, info);

		send_debuggerd_packet(info);

		// 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.
		}

		int rc = syscall(SYS_rt_tgsigqueueinfo, getpid(), gettid(), signal_number, info);
		if (rc != 0) {
		__libc_format_log(ANDROID_LOG_FATAL, "libc", "failed to resend signal during crash: %s",
		strerror(errno));
		_exit(0);
		}
		}

		void debuggerd_init(debuggerd_callbacks_t* callbacks) {
		if (callbacks) {
		g_callbacks = *callbacks;
		}

		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;

		// Use the alternate signal stack if available so we can catch stack overflows.
		action.sa_flags \|= SA_ONSTACK;

		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);
		}

debuggerd/crasher.cpp

+25 −4

Original line number	Diff line number	Diff line
		@@ -16,6 +16,10 @@
		#include <cutils/sockets.h>
		#include <log/log.h>

		#if defined(STATIC_CRASHER)
		#include "debuggerd/client.h"
		#endif

		#ifndef __unused
		#define __unused __attribute__((__unused__))
		#endif
		@@ -43,7 +47,7 @@ __attribute__ ((noinline)) static void smash_stack_dummy_function(volatile int*
		// Assign local array address to global variable to force stack guards.
		// Use another noinline function to corrupt the stack.
		__attribute__ ((noinline)) static int smash_stack(volatile int* plen) {
		printf("crasher: deliberately corrupting stack...\n");
		printf("%s: deliberately corrupting stack...\n", __progname);

		char buf[128];
		smash_stack_dummy_buf = buf;
		@@ -135,7 +139,7 @@ static void sigsegv_non_null() {

		static int do_action(const char* arg)
		{
		fprintf(stderr,"crasher: init pid=%d tid=%d\n", getpid(), gettid());
		fprintf(stderr, "%s: init pid=%d tid=%d\n", __progname, getpid(), gettid());

		if (!strncmp(arg, "thread-", strlen("thread-"))) {
		return do_action_on_thread(arg + strlen("thread-"));
		@@ -209,7 +213,24 @@ static int do_action(const char* arg)

		int main(int argc, char **argv)
		{
		fprintf(stderr,"crasher: built at " __TIME__ "!@\n");
		fprintf(stderr, "%s: built at " __TIME__ "!@\n", __progname);

		#if defined(STATIC_CRASHER)
		debuggerd_callbacks_t callbacks = {
		.get_abort_message = []() {
		static struct {
		size_t size;
		char msg[32];
		} msg;

		msg.size = strlen("dummy abort message");
		memcpy(msg.msg, "dummy abort message", strlen("dummy abort message"));
		return reinterpret_cast<abort_msg_t*>(&msg);
		},
		.post_dump = nullptr
		};
		debuggerd_init(&callbacks);
		#endif

		if (argc > 1) {
		return do_action(argv[1]);

debuggerd/debuggerd.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -562,7 +562,7 @@ static void worker_process(int fd, debugger_request_t& request) {
		// won't necessarily have stopped by the time ptrace() returns. (We
		// currently assume it does.) We write to the file descriptor to
		// ensure that it can run as soon as we call PTRACE_CONT below.
		// See details in bionic/libc/linker/debugger.c, in function
		// See details in client/debuggerd_client.cpp, in function
		// debugger_signal_handler().

		// Attach to the target process.