/*
** Copyright 2013-2014, 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.
*/
#define _GNU_SOURCE /* asprintf for x86 host */
#include <errno.h>
#include <fcntl.h>
#include <poll.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <cutils/list.h>
#include <log/log.h>
#include <log/logger.h>
typedef char bool;
#define false (const bool)0
#define true (const bool)1
#define LOG_FILE_DIR "/dev/log/"
/* timeout in milliseconds */
#define LOG_TIMEOUT_FLUSH 5
#define LOG_TIMEOUT_NEVER -1
#define logger_for_each(logger, logger_list) \
for (logger = node_to_item((logger_list)->node.next, struct logger, node); \
logger != node_to_item(&(logger_list)->node, struct logger, node); \
logger = node_to_item((logger)->node.next, struct logger, node))
/* In the future, we would like to make this list extensible */
static const char *LOG_NAME[LOG_ID_MAX] = {
[LOG_ID_MAIN] = "main",
[LOG_ID_RADIO] = "radio",
[LOG_ID_EVENTS] = "events",
[LOG_ID_SYSTEM] = "system"
};
const char *android_log_id_to_name(log_id_t log_id) {
if (log_id >= LOG_ID_MAX) {
log_id = LOG_ID_MAIN;
}
return LOG_NAME[log_id];
}
static int accessmode(int mode)
{
if ((mode & O_ACCMODE) == O_WRONLY) {
return W_OK;
}
if ((mode & O_ACCMODE) == O_RDWR) {
return R_OK | W_OK;
}
return R_OK;
}
/* repeated fragment */
static int check_allocate_accessible(char **n, const char *b, int mode)
{
*n = NULL;
if (!b) {
return -EINVAL;
}
asprintf(n, LOG_FILE_DIR "%s", b);
if (!*n) {
return -1;
}
return access(*n, accessmode(mode));
}
log_id_t android_name_to_log_id(const char *logName) {
const char *b;
char *n;
int ret;
if (!logName) {
return -1; /* NB: log_id_t is unsigned */
}
b = strrchr(logName, '/');
if (!b) {
b = logName;
} else {
++b;
}
ret = check_allocate_accessible(&n, b, O_RDONLY);
free(n);
if (ret) {
return ret;
}
for(ret = LOG_ID_MIN; ret < LOG_ID_MAX; ++ret) {
const char *l = LOG_NAME[ret];
if (l && !strcmp(b, l)) {
return ret;
}
}
return -1; /* should never happen */
}
struct logger_list {
struct listnode node;
int mode;
unsigned int tail;
pid_t pid;
unsigned int queued_lines;
int timeout_ms;
int error;
bool flush;
bool valid_entry; /* valiant(?) effort to deal with memory starvation */
struct log_msg entry;
};
struct log_list {
struct listnode node;
struct log_msg entry; /* Truncated to event->len() + 1 to save space */
};
struct logger {
struct listnode node;
struct logger_list *top;
int fd;
log_id_t id;
short *revents;
struct listnode log_list;
};
/* android_logger_alloc unimplemented, no use case */
/* android_logger_free not exported */
static void android_logger_free(struct logger *logger)
{
if (!logger) {
return;
}
while (!list_empty(&logger->log_list)) {
struct log_list *entry = node_to_item(
list_head(&logger->log_list), struct log_list, node);
list_remove(&entry->node);
free(entry);
if (logger->top->queued_lines) {
logger->top->queued_lines--;
}
}
if (logger->fd >= 0) {
close(logger->fd);
}
list_remove(&logger->node);
free(logger);
}
log_id_t android_logger_get_id(struct logger *logger)
{
return logger->id;
}
/* worker for sending the command to the logger */
static int logger_ioctl(struct logger *logger, int cmd, int mode)
{
char *n;
int f, ret;
if (!logger || !logger->top) {
return -EFAULT;
}
if (((mode & O_ACCMODE) == O_RDWR)
|| (((mode ^ logger->top->mode) & O_ACCMODE) == 0)) {
return ioctl(logger->fd, cmd);
}
/* We go here if android_logger_list_open got mode wrong for this ioctl */
ret = check_allocate_accessible(&n, android_log_id_to_name(logger->id), mode);
if (ret) {
free(n);
return ret;
}
f = open(n, mode);
free(n);
if (f < 0) {
return f;
}
ret = ioctl(f, cmd);
close (f);
return ret;
}
int android_logger_clear(struct logger *logger)
{
return logger_ioctl(logger, LOGGER_FLUSH_LOG, O_WRONLY);
}
/* returns the total size of the log's ring buffer */
int android_logger_get_log_size(struct logger *logger)
{
return logger_ioctl(logger, LOGGER_GET_LOG_BUF_SIZE, O_RDWR);
}
/*
* returns the readable size of the log's ring buffer (that is, amount of the
* log consumed)
*/
int android_logger_get_log_readable_size(struct logger *logger)
{
return logger_ioctl(logger, LOGGER_GET_LOG_LEN, O_RDONLY);
}
/*
* returns the logger version
*/
int android_logger_get_log_version(struct logger *logger)
{
int ret = logger_ioctl(logger, LOGGER_GET_VERSION, O_RDWR);
return (ret < 0) ? 1 : ret;
}
struct logger_list *android_logger_list_alloc(int mode,
unsigned int tail,
pid_t pid)
{
struct logger_list *logger_list;
logger_list = calloc(1, sizeof(*logger_list));
if (!logger_list) {
return NULL;
}
list_init(&logger_list->node);
logger_list->mode = mode;
logger_list->tail = tail;
logger_list->pid = pid;
return logger_list;
}
/* android_logger_list_register unimplemented, no use case */
/* android_logger_list_unregister unimplemented, no use case */
/* Open the named log and add it to the logger list */
struct logger *android_logger_open(struct logger_list *logger_list,
log_id_t id)
{
struct listnode *node;
struct logger *logger;
char *n;
if (!logger_list || (id >= LOG_ID_MAX)) {
goto err;
}
logger_for_each(logger, logger_list) {
if (logger->id == id) {
goto ok;
}
}
logger = calloc(1, sizeof(*logger));
if (!logger) {
goto err;
}
if (check_allocate_accessible(&n, android_log_id_to_name(id),
logger_list->mode)) {
goto err_name;
}
logger->fd = open(n, logger_list->mode);
if (logger->fd < 0) {
goto err_name;
}
free(n);
logger->id = id;
list_init(&logger->log_list);
list_add_tail(&logger_list->node, &logger->node);
logger->top = logger_list;
logger_list->timeout_ms = LOG_TIMEOUT_FLUSH;
goto ok;
err_name:
free(n);
err_logger:
free(logger);
err:
logger = NULL;
ok:
return logger;
}
/* Open the single named log and make it part of a new logger list */
struct logger_list *android_logger_list_open(log_id_t id,
int mode,
unsigned int tail,
pid_t pid)
{
struct logger_list *logger_list = android_logger_list_alloc(mode, tail, pid);
if (!logger_list) {
return NULL;
}
if (!android_logger_open(logger_list, id)) {
android_logger_list_free(logger_list);
return NULL;
}
return logger_list;
}
/* prevent memory starvation when backfilling */
static unsigned int queue_threshold(struct logger_list *logger_list)
{
return (logger_list->tail < 64) ? 64 : logger_list->tail;
}
static bool low_queue(struct listnode *node)
{
/* low is considered less than 2 */
return list_head(node) == list_tail(node);
}
/* Flush queues in sequential order, one at a time */
static int android_logger_list_flush(struct logger_list *logger_list,
struct log_msg *log_msg)
{
int ret = 0;
struct log_list *firstentry = NULL;
while ((ret == 0)
&& (logger_list->flush
|| (logger_list->queued_lines > logger_list->tail))) {
struct logger *logger;
/* Merge sort */
bool at_least_one_is_low = false;
struct logger *firstlogger = NULL;
firstentry = NULL;
logger_for_each(logger, logger_list) {
struct listnode *node;
struct log_list *oldest = NULL;
/* kernel logger channels not necessarily time-sort order */
list_for_each(node, &logger->log_list) {
struct log_list *entry = node_to_item(node,
struct log_list, node);
if (!oldest
|| (entry->entry.entry.sec < oldest->entry.entry.sec)
|| ((entry->entry.entry.sec == oldest->entry.entry.sec)
&& (entry->entry.entry.nsec < oldest->entry.entry.nsec))) {
oldest = entry;
}
}
if (!oldest) {
at_least_one_is_low = true;
continue;
} else if (low_queue(&logger->log_list)) {
at_least_one_is_low = true;
}
if (!firstentry
|| (oldest->entry.entry.sec < firstentry->entry.entry.sec)
|| ((oldest->entry.entry.sec == firstentry->entry.entry.sec)
&& (oldest->entry.entry.nsec < firstentry->entry.entry.nsec))) {
firstentry = oldest;
firstlogger = logger;
}
}
if (!firstentry) {
break;
}
/* when trimming list, tries to keep one entry behind in each bucket */
if (!logger_list->flush
&& at_least_one_is_low
&& (logger_list->queued_lines < queue_threshold(logger_list))) {
break;
}
/* within tail?, send! */
if ((logger_list->tail == 0)
|| (logger_list->queued_lines <= logger_list->tail)) {
ret = firstentry->entry.entry.hdr_size;
if (!ret) {
ret = sizeof(firstentry->entry.entry_v1);
}
ret += firstentry->entry.entry.len;
memcpy(log_msg->buf, firstentry->entry.buf, ret + 1);
log_msg->extra.id = firstlogger->id;
}
/* next entry */
list_remove(&firstentry->node);
free(firstentry);
if (logger_list->queued_lines) {
logger_list->queued_lines--;
}
}
/* Flushed the list, no longer in tail mode for continuing content */
if (logger_list->flush && !firstentry) {
logger_list->tail = 0;
}
return ret;
}
/* Read from the selected logs */
int android_logger_list_read(struct logger_list *logger_list,
struct log_msg *log_msg)
{
struct logger *logger;
nfds_t nfds;
struct pollfd *p, *pollfds = NULL;
int error = 0, ret = 0;
memset(log_msg, 0, sizeof(struct log_msg));
if (!logger_list) {
return -ENODEV;
}
if (!(accessmode(logger_list->mode) & R_OK)) {
logger_list->error = EPERM;
goto done;
}
nfds = 0;
logger_for_each(logger, logger_list) {
++nfds;
}
if (nfds <= 0) {
error = ENODEV;
goto done;
}
/* Do we have anything to offer from the buffer or state? */
if (logger_list->valid_entry) { /* implies we are also in a flush state */
goto flush;
}
ret = android_logger_list_flush(logger_list, log_msg);
if (ret) {
goto done;
}
if (logger_list->error) { /* implies we are also in a flush state */
goto done;
}
/* Lets start grinding on metal */
pollfds = calloc(nfds, sizeof(struct pollfd));
if (!pollfds) {
error = ENOMEM;
goto flush;
}
p = pollfds;
logger_for_each(logger, logger_list) {
p->fd = logger->fd;
p->events = POLLIN;
logger->revents = &p->revents;
++p;
}
while (!ret && !error) {
int result;
/* If we oversleep it's ok, i.e. ignore EINTR. */
result = TEMP_FAILURE_RETRY(
poll(pollfds, nfds, logger_list->timeout_ms));
if (result <= 0) {
if (result) {
error = errno;
} else if (logger_list->mode & O_NDELAY) {
error = EAGAIN;
} else {
logger_list->timeout_ms = LOG_TIMEOUT_NEVER;
}
logger_list->flush = true;
goto try_flush;
}
logger_list->timeout_ms = LOG_TIMEOUT_FLUSH;
/* Anti starvation */
if (!logger_list->flush
&& (logger_list->queued_lines > (queue_threshold(logger_list) / 2))) {
/* Any queues with input pending that is low? */
bool starving = false;
logger_for_each(logger, logger_list) {
if ((*(logger->revents) & POLLIN)
&& low_queue(&logger->log_list)) {
starving = true;
break;
}
}
/* pushback on any queues that are not low */
if (starving) {
logger_for_each(logger, logger_list) {
if ((*(logger->revents) & POLLIN)
&& !low_queue(&logger->log_list)) {
*(logger->revents) &= ~POLLIN;
}
}
}
}
logger_for_each(logger, logger_list) {
unsigned int hdr_size;
struct log_list *entry;
if (!(*(logger->revents) & POLLIN)) {
continue;
}
memset(logger_list->entry.buf, 0, sizeof(struct log_msg));
/* NOTE: driver guarantees we read exactly one full entry */
result = read(logger->fd, logger_list->entry.buf,
LOGGER_ENTRY_MAX_LEN);
if (result <= 0) {
if (!result) {
error = EIO;
} else if (errno != EINTR) {
error = errno;
}
continue;
}
if (logger_list->pid
&& (logger_list->pid != logger_list->entry.entry.pid)) {
continue;
}
hdr_size = logger_list->entry.entry.hdr_size;
if (!hdr_size) {
hdr_size = sizeof(logger_list->entry.entry_v1);
}
if ((hdr_size > sizeof(struct log_msg))
|| (logger_list->entry.entry.len
> sizeof(logger_list->entry.buf) - hdr_size)
|| (logger_list->entry.entry.len != result - hdr_size)) {
error = EINVAL;
continue;
}
logger_list->entry.extra.id = logger->id;
/* speedup: If not tail, and only one list, send directly */
if (!logger_list->tail
&& (list_head(&logger_list->node)
== list_tail(&logger_list->node))) {
ret = result;
memcpy(log_msg->buf, logger_list->entry.buf, result + 1);
log_msg->extra.id = logger->id;
break;
}
entry = malloc(sizeof(*entry) - sizeof(entry->entry) + result + 1);
if (!entry) {
logger_list->valid_entry = true;
error = ENOMEM;
break;
}
logger_list->queued_lines++;
memcpy(entry->entry.buf, logger_list->entry.buf, result);
entry->entry.buf[result] = '\0';
list_add_tail(&logger->log_list, &entry->node);
}
if (ret <= 0) {
try_flush:
ret = android_logger_list_flush(logger_list, log_msg);
}
}
free(pollfds);
flush:
if (error) {
logger_list->flush = true;
}
if (ret <= 0) {
ret = android_logger_list_flush(logger_list, log_msg);
if (!ret && logger_list->valid_entry) {
ret = logger_list->entry.entry.hdr_size;
if (!ret) {
ret = sizeof(logger_list->entry.entry_v1);
}
ret += logger_list->entry.entry.len;
memcpy(log_msg->buf, logger_list->entry.buf,
sizeof(struct log_msg));
logger_list->valid_entry = false;
}
}
done:
if (logger_list->error) {
error = logger_list->error;
}
if (error) {
logger_list->error = error;
if (!ret) {
ret = -error;
}
}
return ret;
}
/* Close all the logs */
void android_logger_list_free(struct logger_list *logger_list)
{
if (logger_list == NULL) {
return;
}
while (!list_empty(&logger_list->node)) {
struct listnode *node = list_head(&logger_list->node);
struct logger *logger = node_to_item(node, struct logger, node);
android_logger_free(logger);
}
free(logger_list);
}
