diff --git a/liblog/logd_writer.cpp b/liblog/logd_writer.cpp index f5d19cadb..a230749e1 100644 --- a/liblog/logd_writer.cpp +++ b/liblog/logd_writer.cpp @@ -59,7 +59,8 @@ static void GetSocket() { return; } - int new_socket = TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0)); + int new_socket = + TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0)); if (new_socket <= 0) { return; } @@ -90,6 +91,8 @@ int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) struct iovec newVec[nr + headerLength]; android_log_header_t header; size_t i, payloadSize; + static atomic_int dropped; + static atomic_int droppedSecurity; GetSocket(); @@ -107,7 +110,6 @@ int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) return 0; } - header.id = logId; header.tid = gettid(); header.realtime.tv_sec = ts->tv_sec; header.realtime.tv_nsec = ts->tv_nsec; @@ -115,6 +117,44 @@ int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) newVec[0].iov_base = (unsigned char*)&header; newVec[0].iov_len = sizeof(header); + int32_t snapshot = atomic_exchange_explicit(&droppedSecurity, 0, memory_order_relaxed); + if (snapshot) { + android_log_event_int_t buffer; + + header.id = LOG_ID_SECURITY; + buffer.header.tag = LIBLOG_LOG_TAG; + buffer.payload.type = EVENT_TYPE_INT; + buffer.payload.data = snapshot; + + newVec[headerLength].iov_base = &buffer; + newVec[headerLength].iov_len = sizeof(buffer); + + ret = TEMP_FAILURE_RETRY(writev(logd_socket, newVec, 2)); + if (ret != (ssize_t)(sizeof(header) + sizeof(buffer))) { + atomic_fetch_add_explicit(&droppedSecurity, snapshot, memory_order_relaxed); + } + } + snapshot = atomic_exchange_explicit(&dropped, 0, memory_order_relaxed); + if (snapshot && __android_log_is_loggable_len(ANDROID_LOG_INFO, "liblog", strlen("liblog"), + ANDROID_LOG_VERBOSE)) { + android_log_event_int_t buffer; + + header.id = LOG_ID_EVENTS; + buffer.header.tag = LIBLOG_LOG_TAG; + buffer.payload.type = EVENT_TYPE_INT; + buffer.payload.data = snapshot; + + newVec[headerLength].iov_base = &buffer; + newVec[headerLength].iov_len = sizeof(buffer); + + ret = TEMP_FAILURE_RETRY(writev(logd_socket, newVec, 2)); + if (ret != (ssize_t)(sizeof(header) + sizeof(buffer))) { + atomic_fetch_add_explicit(&dropped, snapshot, memory_order_relaxed); + } + } + + header.id = logId; + for (payloadSize = 0, i = headerLength; i < nr + headerLength; i++) { newVec[i].iov_base = vec[i - headerLength].iov_base; payloadSize += newVec[i].iov_len = vec[i - headerLength].iov_len; @@ -128,8 +168,11 @@ int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) } } + // The write below could be lost, but will never block. + // EAGAIN occurs if logd is overloaded, other errors indicate that something went wrong with + // the connection, so we reset it and try again. ret = TEMP_FAILURE_RETRY(writev(logd_socket, newVec, i)); - if (ret < 0) { + if (ret < 0 && errno != EAGAIN) { LogdConnect(); ret = TEMP_FAILURE_RETRY(writev(logd_socket, newVec, i)); @@ -139,5 +182,14 @@ int LogdWrite(log_id_t logId, struct timespec* ts, struct iovec* vec, size_t nr) ret = -errno; } + if (ret > (ssize_t)sizeof(header)) { + ret -= sizeof(header); + } else if (ret < 0) { + atomic_fetch_add_explicit(&dropped, 1, memory_order_relaxed); + if (logId == LOG_ID_SECURITY) { + atomic_fetch_add_explicit(&droppedSecurity, 1, memory_order_relaxed); + } + } + return ret; }