/*
* 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/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <time.h>
#include <unistd.h>
#include <cutils/sockets.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 = -EBADF,
.name = "logd",
.available = logdAvailable,
.open = logdOpen,
.close = logdClose,
.write = logdWrite,
};
/* log_init_lock assumed */
static int logdOpen() {
int i, ret = 0;
i = atomic_load(&logdLoggerWrite.context.sock);
if (i < 0) {
int sock = TEMP_FAILURE_RETRY(
socket(PF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC | SOCK_NONBLOCK, 0));
if (sock < 0) {
ret = -errno;
} 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(sock, (struct sockaddr*)&un,
sizeof(struct sockaddr_un))) < 0) {
ret = -errno;
switch (ret) {
case -ENOTCONN:
case -ECONNREFUSED:
case -ENOENT:
i = atomic_exchange(&logdLoggerWrite.context.sock, ret);
/* FALLTHRU */
default:
break;
}
close(sock);
} else {
ret = atomic_exchange(&logdLoggerWrite.context.sock, sock);
if ((ret >= 0) && (ret != sock)) {
close(ret);
}
ret = 0;
}
}
}
return ret;
}
static void __logdClose(int negative_errno) {
int sock = atomic_exchange(&logdLoggerWrite.context.sock, negative_errno);
if (sock >= 0) {
close(sock);
}
}
static void logdClose() {
__logdClose(-EBADF);
}
static int logdAvailable(log_id_t logId) {
if (logId >= LOG_ID_MAX || logId == LOG_ID_KERNEL) {
return -EINVAL;
}
if (atomic_load(&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;
int sock;
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;
sock = atomic_load(&logdLoggerWrite.context.sock);
if (sock < 0) switch (sock) {
case -ENOTCONN:
case -ECONNREFUSED:
case -ENOENT:
break;
default:
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 (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(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_len(ANDROID_LOG_INFO, "liblog",
strlen("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(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 has died.
* ENOENT occurs if logd is not running and socket is missing.
* ECONNREFUSED occurs if we can not reconnect to logd.
* EAGAIN occurs if logd is overloaded.
*/
if (sock < 0) {
ret = sock;
} else {
ret = TEMP_FAILURE_RETRY(writev(sock, newVec, i));
if (ret < 0) {
ret = -errno;
}
}
switch (ret) {
case -ENOTCONN:
case -ECONNREFUSED:
case -ENOENT:
if (__android_log_trylock()) {
return ret; /* in a signal handler? try again when less stressed */
}
__logdClose(ret);
ret = logdOpen();
__android_log_unlock();
if (ret < 0) {
return ret;
}
ret = TEMP_FAILURE_RETRY(
writev(atomic_load(&logdLoggerWrite.context.sock), newVec, i));
if (ret < 0) {
ret = -errno;
}
/* FALLTHRU */
default:
break;
}
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;
}
