liblog: split out transports into separate files
Create config_logger, logger and logger_read to house the log
interfaces. Add fake_logger, logd_logger and pmsg_logger to
house the write and read transports. Allows for an easier and
direct path to add new transports to the library.
SideEffects: None, logger benchmark performance unaffected
Bug: 27176738
Bug: 27405083
Change-Id: I01b38637334a5242905c8c89f6ab0a92e2540008
diff --git a/liblog/logd_writer.c b/liblog/logd_writer.c
new file mode 100644
index 0000000..696237d
--- /dev/null
+++ b/liblog/logd_writer.c
@@ -0,0 +1,267 @@
+/*
+ * Copyright (C) 2007-2016 The Android Open Source Project
+ *
+ * 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
+ *
+ * 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 <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <poll.h>
+#include <stdarg.h>
+#include <stdatomic.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <cutils/sockets.h>
+#include <log/logd.h>
+#include <log/logger.h>
+#include <log/log_read.h>
+#include <private/android_filesystem_config.h>
+#include <private/android_logger.h>
+
+#include "config_write.h"
+#include "log_portability.h"
+#include "logger.h"
+
+/* branchless on many architectures. */
+#define min(x,y) ((y) ^ (((x) ^ (y)) & -((x) < (y))))
+
+static int logdAvailable(log_id_t LogId);
+static int logdOpen();
+static void logdClose();
+static int logdWrite(log_id_t logId, struct timespec *ts,
+ struct iovec *vec, size_t nr);
+
+LIBLOG_HIDDEN struct android_log_transport_write logdLoggerWrite = {
+ .node = { &logdLoggerWrite.node, &logdLoggerWrite.node },
+ .context.sock = -1,
+ .name = "logd",
+ .available = logdAvailable,
+ .open = logdOpen,
+ .close = logdClose,
+ .write = logdWrite,
+};
+
+/* log_init_lock assumed */
+static int logdOpen()
+{
+ int i, ret = 0;
+
+ if (logdLoggerWrite.context.sock < 0) {
+ i = TEMP_FAILURE_RETRY(socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0));
+ if (i < 0) {
+ ret = -errno;
+ } else if (TEMP_FAILURE_RETRY(fcntl(i, F_SETFL, O_NONBLOCK)) < 0) {
+ ret = -errno;
+ close(i);
+ } else {
+ struct sockaddr_un un;
+ memset(&un, 0, sizeof(struct sockaddr_un));
+ un.sun_family = AF_UNIX;
+ strcpy(un.sun_path, "/dev/socket/logdw");
+
+ if (TEMP_FAILURE_RETRY(connect(i, (struct sockaddr *)&un,
+ sizeof(struct sockaddr_un))) < 0) {
+ ret = -errno;
+ close(i);
+ } else {
+ logdLoggerWrite.context.sock = i;
+ }
+ }
+ }
+
+ return ret;
+}
+
+static void logdClose()
+{
+ if (logdLoggerWrite.context.sock >= 0) {
+ close(logdLoggerWrite.context.sock);
+ logdLoggerWrite.context.sock = -1;
+ }
+}
+
+static int logdAvailable(log_id_t logId)
+{
+ if (logId > LOG_ID_SECURITY) {
+ return -EINVAL;
+ }
+ if (logId == LOG_ID_SECURITY) {
+ uid_t uid = __android_log_uid();
+ if ((uid != AID_LOG) && (uid != AID_ROOT) && (uid != AID_SYSTEM)) {
+ return -EPERM;
+ }
+ }
+ if (logdLoggerWrite.context.sock < 0) {
+ if (access("/dev/socket/logdw", W_OK) == 0) {
+ return 0;
+ }
+ return -EBADF;
+ }
+ return 1;
+}
+
+static int logdWrite(log_id_t logId, struct timespec *ts,
+ struct iovec *vec, size_t nr)
+{
+ ssize_t ret;
+ static const unsigned headerLength = 1;
+ struct iovec newVec[nr + headerLength];
+ android_log_header_t header;
+ size_t i, payloadSize;
+ static atomic_int_fast32_t dropped;
+ static atomic_int_fast32_t droppedSecurity;
+
+ if (logdLoggerWrite.context.sock < 0) {
+ return -EBADF;
+ }
+
+ /* logd, after initialization and priv drop */
+ if (__android_log_uid() == AID_LOGD) {
+ /*
+ * ignore log messages we send to ourself (logd).
+ * Such log messages are often generated by libraries we depend on
+ * which use standard Android logging.
+ */
+ return 0;
+ }
+
+ /*
+ * struct {
+ * // what we provide to socket
+ * android_log_header_t header;
+ * // caller provides
+ * union {
+ * struct {
+ * char prio;
+ * char payload[];
+ * } string;
+ * struct {
+ * uint32_t tag
+ * char payload[];
+ * } binary;
+ * };
+ * };
+ */
+
+ header.tid = gettid();
+ header.realtime.tv_sec = ts->tv_sec;
+ header.realtime.tv_nsec = ts->tv_nsec;
+
+ newVec[0].iov_base = (unsigned char *)&header;
+ newVec[0].iov_len = sizeof(header);
+
+ if (logdLoggerWrite.context.sock > 0) {
+ 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 = htole32(LIBLOG_LOG_TAG);
+ buffer.payload.type = EVENT_TYPE_INT;
+ buffer.payload.data = htole32(snapshot);
+
+ newVec[headerLength].iov_base = &buffer;
+ newVec[headerLength].iov_len = sizeof(buffer);
+
+ ret = TEMP_FAILURE_RETRY(writev(logdLoggerWrite.context.sock, 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(ANDROID_LOG_INFO,
+ "liblog",
+ ANDROID_LOG_VERBOSE)) {
+ android_log_event_int_t buffer;
+
+ header.id = LOG_ID_EVENTS;
+ buffer.header.tag = htole32(LIBLOG_LOG_TAG);
+ buffer.payload.type = EVENT_TYPE_INT;
+ buffer.payload.data = htole32(snapshot);
+
+ newVec[headerLength].iov_base = &buffer;
+ newVec[headerLength].iov_len = sizeof(buffer);
+
+ ret = TEMP_FAILURE_RETRY(writev(logdLoggerWrite.context.sock, 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;
+
+ if (payloadSize > LOGGER_ENTRY_MAX_PAYLOAD) {
+ newVec[i].iov_len -= payloadSize - LOGGER_ENTRY_MAX_PAYLOAD;
+ if (newVec[i].iov_len) {
+ ++i;
+ }
+ break;
+ }
+ }
+
+ /*
+ * The write below could be lost, but will never block.
+ *
+ * ENOTCONN occurs if logd dies.
+ * EAGAIN occurs if logd is overloaded.
+ */
+ ret = TEMP_FAILURE_RETRY(writev(logdLoggerWrite.context.sock, newVec, i));
+ if (ret < 0) {
+ ret = -errno;
+ if (ret == -ENOTCONN) {
+ __android_log_lock();
+ logdClose();
+ ret = logdOpen();
+ __android_log_unlock();
+
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = TEMP_FAILURE_RETRY(writev(logdLoggerWrite.context.sock, newVec, i));
+ if (ret < 0) {
+ ret = -errno;
+ }
+ }
+ }
+
+ if (ret > (ssize_t)sizeof(header)) {
+ ret -= sizeof(header);
+ } else if (ret == -EAGAIN) {
+ 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;
+}