include/private/android_logger.h

/*
 * Copyright (C) 2015 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.
 */

/* This file is used to define the internal protocol for the Android Logger */

#ifndef _SYSTEM_CORE_INCLUDE_PRIVATE_ANDROID_LOGGER_H_
#define _SYSTEM_CORE_INCLUDE_PRIVATE_ANDROID_LOGGER_H_

/* Android private interfaces */

#include <stdint.h>
#include <sys/types.h>

#include <log/log.h>
#include <log/log_read.h>

#define LOGGER_MAGIC 'l'

/* Header Structure to pstore */
typedef struct __attribute__((__packed__)) {
    uint8_t magic;
    uint16_t len;
    uint16_t uid;
    uint16_t pid;
} android_pmsg_log_header_t;

/* Header Structure to logd, and second header for pstore */
typedef struct __attribute__((__packed__)) {
    typeof_log_id_t id;
    uint16_t tid;
    log_time realtime;
} android_log_header_t;

/* Event Header Structure to logd */
typedef struct __attribute__((__packed__)) {
    int32_t tag;  // Little Endian Order
} android_event_header_t;

/* Event payload EVENT_TYPE_INT */
typedef struct __attribute__((__packed__)) {
    int8_t type;  // EVENT_TYPE_INT
    int32_t data; // Little Endian Order
} android_event_int_t;

/* Event with single EVENT_TYPE_INT */
typedef struct __attribute__((__packed__)) {
    android_event_header_t header;
    android_event_int_t payload;
} android_log_event_int_t;

/* Event payload EVENT_TYPE_LONG */
typedef struct __attribute__((__packed__)) {
    int8_t type;  // EVENT_TYPE_LONG
    int64_t data; // Little Endian Order
} android_event_long_t;

/* Event with single EVENT_TYPE_LONG */
typedef struct __attribute__((__packed__)) {
    android_event_header_t header;
    android_event_long_t payload;
} android_log_event_long_t;

/*
 * Event payload EVENT_TYPE_STRING
 *
 * Danger: do not embed this structure into another structure.
 * This structure uses a flexible array member, and when
 * compiled using g++, __builtin_object_size(data, 1) returns
 * a bad value. This is possibly a g++ bug, or a bug due to
 * the fact that flexible array members are not supported
 * in C++.
 * http://stackoverflow.com/questions/4412749/are-flexible-array-members-valid-in-c
 */
typedef struct __attribute__((__packed__)) {
    int8_t type;    // EVENT_TYPE_STRING;
    int32_t length; // Little Endian Order
    char data[];
} android_event_string_t;

/* Event with single EVENT_TYPE_STRING */
typedef struct __attribute__((__packed__)) {
    android_event_header_t header;
    int8_t type;    // EVENT_TYPE_STRING;
    int32_t length; // Little Endian Order
    char data[];
} android_log_event_string_t;

#if defined(__cplusplus)
extern "C" {
#endif

#define ANDROID_LOG_PMSG_FILE_MAX_SEQUENCE 256 /* 1MB file */
#define ANDROID_LOG_PMSG_FILE_SEQUENCE     1000

ssize_t __android_log_pmsg_file_write(
        log_id_t logId,
        char prio,
        const char *filename,
        const char *buf, size_t len);

#define LOG_ID_ANY      ((log_id_t)-1)
#define ANDROID_LOG_ANY ANDROID_LOG_UNKNOWN

/* first 5 arguments match __android_log_msg_file_write, a cast is safe */
typedef ssize_t (*__android_log_pmsg_file_read_fn)(
        log_id_t logId,
        char prio,
        const char *filename,
        const char *buf, size_t len, void *arg);

ssize_t __android_log_pmsg_file_read(
        log_id_t logId, char prio, const char *prefix,
        __android_log_pmsg_file_read_fn fn, void *arg);

#if defined(__cplusplus)
}
#endif

#endif /* _SYSTEM_CORE_INCLUDE_PRIVATE_ANDROID_LOGGER_H_ */