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

#if (defined(__cplusplus) && defined(_USING_LIBCXX))
extern "C++" {
#include <string>
}
#endif

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

#define LOGGER_MAGIC 'l'

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

/* 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;

#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);

int __android_log_security_bwrite(int32_t tag, const void* payload, size_t len);
int __android_log_security_bswrite(int32_t tag, const char* payload);
int __android_log_security(); /* Device Owner is present */

int __android_log_is_debuggable();

#define BOOL_DEFAULT_FLAG_TRUE_FALSE 0x1
#define BOOL_DEFAULT_FALSE       0x0     /* false if property not present   */
#define BOOL_DEFAULT_TRUE        0x1     /* true if property not present    */
#define BOOL_DEFAULT_FLAG_PERSIST    0x2 /* <key>, persist.<key>, ro.<key>  */
#define BOOL_DEFAULT_FLAG_ENG        0x4 /* off for user                    */
#define BOOL_DEFAULT_FLAG_SVELTE     0x8 /* off for low_ram                 */
bool __android_logger_property_get_bool(const char* key, int flag);

#define LOG_BUFFER_SIZE (256 * 1024) /* Tuned with ro.logd.size per-platform */
#define LOG_BUFFER_MIN_SIZE (64 * 1024UL)
#define LOG_BUFFER_MAX_SIZE (256 * 1024 * 1024UL)
unsigned long __android_logger_get_buffer_size(log_id_t logId);
bool __android_logger_valid_buffer_size(unsigned long value);

/* Retrieve the composed event buffer */
int android_log_write_list_buffer(android_log_context ctx, const char** msg);

#ifdef __cplusplus
#ifdef __class_android_log_event_list_defined
#ifndef __class_android_log_event_list_private_defined
#define __class_android_log_event_list_private_defined
/* android_log_context C++ helpers */
extern "C++" {
class __android_log_event_list : public android_log_event_list {
    __android_log_event_list(const android_log_event_list&) = delete;
    void operator =(const __android_log_event_list&) = delete;

public:
    explicit __android_log_event_list(int tag) : android_log_event_list(tag) { }
    explicit __android_log_event_list(log_msg& log_msg) : android_log_event_list(log_msg) { }

#if defined(_USING_LIBCXX)
    operator std::string() {
        if (ret) return std::string("");
        const char* cp = NULL;
        ssize_t len = android_log_write_list_buffer(ctx, &cp);
        if (len < 0) ret = len;
        if (!cp || (len <= 0)) return std::string("");
        return std::string(cp, len);
    }
#endif

};
}
#endif
#endif
#endif

#if defined(__cplusplus)
}
#endif

#endif /* _SYSTEM_CORE_INCLUDE_PRIVATE_ANDROID_LOGGER_H_ */