liblog: Interface to support abstracting log read (6c1b07fb) · Commits · e / os / android_system_core

include/log/log.h

+15 −15

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2005 The Android Open Source Project
		* Copyright (C) 2005-2013 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.
		@@ -28,21 +28,19 @@
		#ifndef _LIBS_LOG_LOG_H
		#define _LIBS_LOG_LOG_H

		#include <stdio.h>
		#include <time.h>
		#include <sys/cdefs.h>
		#include <sys/types.h>
		#include <unistd.h>
		#ifdef HAVE_PTHREADS
		#include <pthread.h>
		#endif
		#include <stdarg.h>

		#include <log/uio.h>
		#include <stdio.h>
		#include <time.h>
		#include <unistd.h>
		#include <log/logd.h>
		#include <log/uio.h>

		#ifdef __cplusplus
		extern "C" {
		#endif
		__BEGIN_DECLS

		// ---------------------------------------------------------------------

		@@ -470,7 +468,8 @@ typedef enum {
		EVENT_TYPE_STRING = 2,
		EVENT_TYPE_LIST = 3,
		} AndroidEventLogType;

		#define sizeof_AndroidEventLogType sizeof(typeof_AndroidEventLogType)
		#define typeof_AndroidEventLogType unsigned char

		#ifndef LOG_EVENT_INT
		#define LOG_EVENT_INT(_tag, _value) { \
		@@ -540,7 +539,9 @@ typedef enum {
		#define android_logToFile(tag, file) (0)
		#define android_logToFd(tag, fd) (0)

		typedef enum {
		typedef enum log_id {
		LOG_ID_MIN = 0,

		LOG_ID_MAIN = 0,
		LOG_ID_RADIO = 1,
		LOG_ID_EVENTS = 2,
		@@ -548,6 +549,8 @@ typedef enum {

		LOG_ID_MAX
		} log_id_t;
		#define sizeof_log_id_t sizeof(typeof_log_id_t)
		#define typeof_log_id_t unsigned char

		/*
		* Send a simple string to the log.
		@@ -555,9 +558,6 @@ typedef enum {
		int __android_log_buf_write(int bufID, int prio, const char tag, const char text);
		int __android_log_buf_print(int bufID, int prio, const char tag, const char fmt, ...);


		#ifdef __cplusplus
		}
		#endif
		__END_DECLS

		#endif // _LIBS_CUTILS_LOG_H

include/log/logger.h

+108 −2

Original line number	Diff line number	Diff line
		/* utils/logger.h
		/*
		**
		** Copyright 2007, The Android Open Source Project
		**
		@@ -10,7 +10,11 @@
		#ifndef _UTILS_LOGGER_H
		#define _UTILS_LOGGER_H

		#include <sys/cdefs.h>
		#include <stdint.h>
		#include <log/log.h>

		__BEGIN_DECLS

		/*
		* The userspace structure for version 1 of the logger_entry ABI.
		@@ -63,6 +67,106 @@ struct logger_entry_v2 {
		*/
		#define LOGGER_ENTRY_MAX_LEN (5*1024)

		#define NS_PER_SEC 1000000000ULL

		struct log_msg {
		union {
		unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1];
		struct logger_entry_v2 entry;
		struct logger_entry_v2 entry_v2;
		struct logger_entry entry_v1;
		struct {
		unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1];
		log_id_t id;
		} extra;
		} __attribute__((aligned(4)));
		#ifdef __cplusplus
		/* Matching log_time_t operators */
		bool operator== (log_msg &T)
		{
		return (entry.sec == T.entry.sec) && (entry.nsec == T.entry.nsec);
		}
		bool operator!= (log_msg &T)
		{
		return !(*this == T);
		}
		bool operator< (log_msg &T)
		{
		return (entry.sec < T.entry.sec)
		\|\| ((entry.sec == T.entry.sec)
		&& (entry.nsec < T.entry.nsec));
		}
		bool operator>= (log_msg &T)
		{
		return !(*this < T);
		}
		bool operator> (log_msg &T)
		{
		return (entry.sec > T.entry.sec)
		\|\| ((entry.sec == T.entry.sec)
		&& (entry.nsec > T.entry.nsec));
		}
		bool operator<= (log_msg &T)
		{
		return !(*this > T);
		}
		uint64_t nsec(void)
		{
		return static_cast<uint64_t>(entry.sec) * NS_PER_SEC + entry.nsec;
		}

		/* packet methods */
		log_id_t id(void)
		{
		return extra.id;
		}
		char *msg(void)
		{
		return entry.hdr_size ? (char *) buf + entry.hdr_size : entry_v1.msg;
		}
		unsigned int len(void)
		{
		return (entry.hdr_size ? entry.hdr_size : sizeof(entry_v1)) + entry.len;
		}
		#endif
		};

		struct logger;

		log_id_t android_logger_get_id(struct logger *logger);

		int android_logger_clear(struct logger *logger);
		int android_logger_get_log_size(struct logger *logger);
		int android_logger_get_log_readable_size(struct logger *logger);
		int android_logger_get_log_version(struct logger *logger);

		struct logger_list;

		struct logger_list *android_logger_list_alloc(int mode,
		unsigned int tail,
		pid_t pid);
		void android_logger_list_free(struct logger_list *logger_list);
		/* In the purest sense, the following two are orthogonal interfaces */
		int android_logger_list_read(struct logger_list *logger_list,
		struct log_msg *log_msg);

		/* Multiple log_id_t opens */
		struct logger android_logger_open(struct logger_list logger_list,
		log_id_t id);
		#define android_logger_close android_logger_free
		/* Single log_id_t open */
		struct logger_list *android_logger_list_open(log_id_t id,
		int mode,
		unsigned int tail,
		pid_t pid);
		#define android_logger_list_close android_logger_list_free

		/*
		* log_id_t helpers
		*/
		log_id_t android_name_to_log_id(const char *logName);
		const char *android_log_id_to_name(log_id_t log_id);

		#ifdef HAVE_IOCTL

		#include <sys/ioctl.h>
		@@ -78,4 +182,6 @@ struct logger_entry_v2 {

		#endif // HAVE_IOCTL

		__END_DECLS

		#endif /* _UTILS_LOGGER_H */

liblog/Android.mk

+1 −0

Original line number	Diff line number	Diff line
		@@ -35,6 +35,7 @@ endif
		ifndef WITH_MINGW
		liblog_sources += \
		logprint.c \
		log_read.c \
		event_tag_map.c
		else
		liblog_sources += \

liblog/log_read.c

0 → 100644

+652 −0

Original line number	Diff line number	Diff line
		/*
		** Copyright 2013, 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/"

		#define LOG_TIMEOUT_MS 5

		#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_MS;
		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 = 0;
		}

		logger_list->flush = true;
		goto try_flush;
		}

		logger_list->timeout_ms = LOG_TIMEOUT_MS;

		/* 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);
		}