logd: liblog: ALOG silently drops excessively long messages (8444eb81) · Commits · e / os / android_system_core

liblog/logd_write.c

+29 −14

Original line number	Diff line number	Diff line
		@@ -146,9 +146,15 @@ static int __write_to_log_kernel(log_id_t log_id, struct iovec *vec, size_t nr)
		ret = -errno;
		}
		} while (ret == -EINTR);

		return ret;
		#else
		static const unsigned header_length = 3;
		struct iovec newVec[nr + header_length];
		typeof_log_id_t log_id_buf;
		uint16_t tid;
		struct timespec ts;
		log_time realtime_ts;
		size_t i, payload_size;

		if (getuid() == AID_LOGD) {
		/*
		* ignore log messages we send to ourself.
		@@ -181,29 +187,33 @@ static int __write_to_log_kernel(log_id_t log_id, struct iovec *vec, size_t nr)
		* };
		* };
		*/
		static const unsigned header_length = 3;
		struct iovec newVec[nr + header_length];
		typeof_log_id_t log_id_buf = log_id;
		uint16_t tid = gettid();

		log_id_buf = log_id;
		tid = gettid();

		newVec[0].iov_base = (unsigned char *) &log_id_buf;
		newVec[0].iov_len = sizeof_log_id_t;
		newVec[1].iov_base = (unsigned char *) &tid;
		newVec[1].iov_len = sizeof(tid);

		struct timespec ts;
		clock_gettime(CLOCK_REALTIME, &ts);
		log_time realtime_ts;
		realtime_ts.tv_sec = ts.tv_sec;
		realtime_ts.tv_nsec = ts.tv_nsec;

		newVec[2].iov_base = (unsigned char *) &realtime_ts;
		newVec[2].iov_len = sizeof(log_time);

		size_t i;
		for (i = header_length; i < nr + header_length; i++) {
		for (payload_size = 0, i = header_length; i < nr + header_length; i++) {
		newVec[i].iov_base = vec[i - header_length].iov_base;
		newVec[i].iov_len = vec[i-header_length].iov_len;
		payload_size += newVec[i].iov_len = vec[i - header_length].iov_len;

		if (payload_size > LOGGER_ENTRY_MAX_PAYLOAD) {
		newVec[i].iov_len -= payload_size - LOGGER_ENTRY_MAX_PAYLOAD;
		if (newVec[i].iov_len) {
		++i;
		}
		break;
		}
		}

		/*
		@@ -212,7 +222,7 @@ static int __write_to_log_kernel(log_id_t log_id, struct iovec *vec, size_t nr)
		* ENOTCONN occurs if logd dies.
		* EAGAIN occurs if logd is overloaded.
		*/
		ret = writev(logd_fd, newVec, nr + header_length);
		ret = writev(logd_fd, newVec, i);
		if (ret < 0) {
		ret = -errno;
		if (ret == -ENOTCONN) {
		@@ -234,8 +244,13 @@ static int __write_to_log_kernel(log_id_t log_id, struct iovec *vec, size_t nr)
		}
		}
		}
		return ret;

		if (ret > (ssize_t)(sizeof_log_id_t + sizeof(tid) + sizeof(log_time))) {
		ret -= sizeof_log_id_t + sizeof(tid) + sizeof(log_time);
		}
		#endif

		return ret;
		}

		#if FAKE_LOG_DEVICE

liblog/tests/liblog_test.cpp

+57 −0

Original line number	Diff line number	Diff line
		@@ -482,11 +482,68 @@ TEST(liblog, max_payload) {
		}
		}

		android_logger_list_close(logger_list);

		EXPECT_EQ(true, matches);

		EXPECT_LE(sizeof(max_payload_buf), static_cast<size_t>(max_len));
		}

		TEST(liblog, too_big_payload) {
		pid_t pid = getpid();
		static const char big_payload_tag[] = "TEST_big_payload_XXXX";
		char tag[sizeof(big_payload_tag)];
		memcpy(tag, big_payload_tag, sizeof(tag));
		snprintf(tag + sizeof(tag) - 5, 5, "%04X", pid & 0xFFFF);

		std::string longString(3266519, 'x');

		ssize_t ret = LOG_FAILURE_RETRY(__android_log_buf_write(LOG_ID_SYSTEM,
		ANDROID_LOG_INFO, tag, longString.c_str()));

		struct logger_list *logger_list;

		ASSERT_TRUE(NULL != (logger_list = android_logger_list_open(
		LOG_ID_SYSTEM, O_RDONLY \| O_NDELAY, 100, 0)));

		ssize_t max_len = 0;

		for(;;) {
		log_msg log_msg;
		if (android_logger_list_read(logger_list, &log_msg) <= 0) {
		break;
		}

		if ((log_msg.entry.pid != pid) \|\| (log_msg.id() != LOG_ID_SYSTEM)) {
		continue;
		}

		char *data = log_msg.msg() + 1;

		if (strcmp(data, tag)) {
		continue;
		}

		data += strlen(data) + 1;

		const char *left = data;
		const char *right = longString.c_str();
		while (left && right && (left == right)) {
		++left;
		++right;
		}

		if (max_len <= (left - data)) {
		max_len = left - data + 1;
		}
		}

		android_logger_list_close(logger_list);

		EXPECT_LE(LOGGER_ENTRY_MAX_PAYLOAD - sizeof(big_payload_tag),
		static_cast<size_t>(max_len));

		EXPECT_EQ(ret, max_len + sizeof(big_payload_tag));
		}

		TEST(liblog, dual_reader) {

logd/LogListener.cpp

+1 −1

Original line number	Diff line number	Diff line
		@@ -31,7 +31,7 @@ LogListener::LogListener(LogBuffer buf, LogReader reader)
		{ }

		bool LogListener::onDataAvailable(SocketClient *cli) {
		char buffer[sizeof_log_id_t + sizeof(log_time) + sizeof(char)
		char buffer[sizeof_log_id_t + sizeof(uint16_t) + sizeof(log_time)
		+ LOGGER_ENTRY_MAX_PAYLOAD];
		struct iovec iov = { buffer, sizeof(buffer) };
		memset(buffer, 0, sizeof(buffer));