/*
 * Copyright (C) 2005-2017 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.
 */

#ifndef _LIBS_LOG_LOG_READ_H
#define _LIBS_LOG_LOG_READ_H

/* deal with possible sys/cdefs.h conflict with fcntl.h */
#ifdef __unused
#define __unused_defined __unused
#undef __unused
#endif

#include <fcntl.h> /* Pick up O_* macros */

/* restore definitions from above */
#ifdef __unused_defined
#define __unused __attribute__((__unused__))
#endif

#include <stdint.h>

#include <log/log_id.h>
#include <log/log_time.h>

#ifdef __cplusplus
extern "C" {
#endif

/*
 * Native log reading interface section. See logcat for sample code.
 *
 * The preferred API is an exec of logcat. Likely uses of this interface
 * are if native code suffers from exec or filtration being too costly,
 * access to raw information, or parsing is an issue.
 */

/*
 * The userspace structure for version 1 of the logger_entry ABI.
 */
#ifndef __struct_logger_entry_defined
#define __struct_logger_entry_defined
struct logger_entry {
    uint16_t    len;    /* length of the payload */
    uint16_t    __pad;  /* no matter what, we get 2 bytes of padding */
    int32_t     pid;    /* generating process's pid */
    int32_t     tid;    /* generating process's tid */
    int32_t     sec;    /* seconds since Epoch */
    int32_t     nsec;   /* nanoseconds */
#ifndef __cplusplus
    char        msg[0]; /* the entry's payload */
#endif
};
#endif

/*
 * The userspace structure for version 2 of the logger_entry ABI.
 */
#ifndef __struct_logger_entry_v2_defined
#define __struct_logger_entry_v2_defined
struct logger_entry_v2 {
    uint16_t    len;       /* length of the payload */
    uint16_t    hdr_size;  /* sizeof(struct logger_entry_v2) */
    int32_t     pid;       /* generating process's pid */
    int32_t     tid;       /* generating process's tid */
    int32_t     sec;       /* seconds since Epoch */
    int32_t     nsec;      /* nanoseconds */
    uint32_t    euid;      /* effective UID of logger */
#ifndef __cplusplus
    char        msg[0];    /* the entry's payload */
#endif
} __attribute__((__packed__));
#endif

/*
 * The userspace structure for version 3 of the logger_entry ABI.
 */
#ifndef __struct_logger_entry_v3_defined
#define __struct_logger_entry_v3_defined
struct logger_entry_v3 {
    uint16_t    len;       /* length of the payload */
    uint16_t    hdr_size;  /* sizeof(struct logger_entry_v3) */
    int32_t     pid;       /* generating process's pid */
    int32_t     tid;       /* generating process's tid */
    int32_t     sec;       /* seconds since Epoch */
    int32_t     nsec;      /* nanoseconds */
    uint32_t    lid;       /* log id of the payload */
#ifndef __cplusplus
    char        msg[0];    /* the entry's payload */
#endif
} __attribute__((__packed__));
#endif

/*
 * The userspace structure for version 4 of the logger_entry ABI.
 */
#ifndef __struct_logger_entry_v4_defined
#define __struct_logger_entry_v4_defined
struct logger_entry_v4 {
    uint16_t    len;       /* length of the payload */
    uint16_t    hdr_size;  /* sizeof(struct logger_entry_v4) */
    int32_t     pid;       /* generating process's pid */
    uint32_t    tid;       /* generating process's tid */
    uint32_t    sec;       /* seconds since Epoch */
    uint32_t    nsec;      /* nanoseconds */
    uint32_t    lid;       /* log id of the payload, bottom 4 bits currently */
    uint32_t    uid;       /* generating process's uid */
#ifndef __cplusplus
    char        msg[0];    /* the entry's payload */
#endif
};
#endif

/*
 * The maximum size of the log entry payload that can be
 * written to the logger. An attempt to write more than
 * this amount will result in a truncated log entry.
 */
#define LOGGER_ENTRY_MAX_PAYLOAD 4068

/*
 * The maximum size of a log entry which can be read.
 * An attempt to read less than this amount may result
 * in read() returning EINVAL.
 */
#define LOGGER_ENTRY_MAX_LEN    (5*1024)

#ifndef __struct_log_msg_defined
#define __struct_log_msg_defined
struct log_msg {
    union {
        unsigned char buf[LOGGER_ENTRY_MAX_LEN + 1];
        struct logger_entry_v4 entry;
        struct logger_entry_v4 entry_v4;
        struct logger_entry_v3 entry_v3;
        struct logger_entry_v2 entry_v2;
        struct logger_entry    entry_v1;
    } __attribute__((aligned(4)));
#ifdef __cplusplus
    /* Matching log_time operators */
    bool operator== (const log_msg& T) const
    {
        return (entry.sec == T.entry.sec) && (entry.nsec == T.entry.nsec);
    }
    bool operator!= (const log_msg& T) const
    {
        return !(*this == T);
    }
    bool operator< (const log_msg& T) const
    {
        return (entry.sec < T.entry.sec)
            || ((entry.sec == T.entry.sec)
             && (entry.nsec < T.entry.nsec));
    }
    bool operator>= (const log_msg& T) const
    {
        return !(*this < T);
    }
    bool operator> (const log_msg& T) const
    {
        return (entry.sec > T.entry.sec)
            || ((entry.sec == T.entry.sec)
             && (entry.nsec > T.entry.nsec));
    }
    bool operator<= (const log_msg& T) const
    {
        return !(*this > T);
    }
    uint64_t nsec() const
    {
        return static_cast<uint64_t>(entry.sec) * NS_PER_SEC + entry.nsec;
    }

    /* packet methods */
    log_id_t id()
    {
        return static_cast<log_id_t>(entry.lid);
    }
    char* msg()
    {
        unsigned short hdr_size = entry.hdr_size;
        if (!hdr_size) {
            hdr_size = sizeof(entry_v1);
        }
        if ((hdr_size < sizeof(entry_v1)) || (hdr_size > sizeof(entry))) {
            return NULL;
        }
        return reinterpret_cast<char*>(buf) + hdr_size;
    }
    unsigned int len()
    {
        return (entry.hdr_size ?
                    entry.hdr_size :
                    static_cast<uint16_t>(sizeof(entry_v1))) +
               entry.len;
    }
#endif
};
#endif

#ifndef __ANDROID_USE_LIBLOG_READER_INTERFACE
#ifndef __ANDROID_API__
#define __ANDROID_USE_LIBLOG_READER_INTERFACE 3
#elif __ANDROID_API__ > 23 /* > Marshmallow */
#define __ANDROID_USE_LIBLOG_READER_INTERFACE 3
#elif __ANDROID_API__ > 22 /* > Lollipop */
#define __ANDROID_USE_LIBLOG_READER_INTERFACE 2
#elif __ANDROID_API__ > 19 /* > KitKat */
#define __ANDROID_USE_LIBLOG_READER_INTERFACE 1
#else
#define __ANDROID_USE_LIBLOG_READER_INTERFACE 0
#endif
#endif

#if __ANDROID_USE_LIBLOG_READER_INTERFACE

struct logger;

log_id_t android_logger_get_id(struct logger* logger);

int android_logger_clear(struct logger* logger);
long android_logger_get_log_size(struct logger* logger);
int android_logger_set_log_size(struct logger* logger, unsigned long size);
long android_logger_get_log_readable_size(struct logger* logger);
int android_logger_get_log_version(struct logger* logger);

struct logger_list;

#if __ANDROID_USE_LIBLOG_READER_INTERFACE > 1
ssize_t android_logger_get_statistics(struct logger_list* logger_list,
                                      char* buf, size_t len);
ssize_t android_logger_get_prune_list(struct logger_list* logger_list,
                                      char* buf, size_t len);
int android_logger_set_prune_list(struct logger_list* logger_list,
                                  char* buf, size_t len);
#endif

#define ANDROID_LOG_RDONLY   O_RDONLY
#define ANDROID_LOG_WRONLY   O_WRONLY
#define ANDROID_LOG_RDWR     O_RDWR
#define ANDROID_LOG_ACCMODE  O_ACCMODE
#ifndef O_NONBLOCK
#define ANDROID_LOG_NONBLOCK 0x00000800
#else
#define ANDROID_LOG_NONBLOCK O_NONBLOCK
#endif
#if __ANDROID_USE_LIBLOG_READER_INTERFACE > 2
#define ANDROID_LOG_WRAP     0x40000000 /* Block until buffer about to wrap */
#define ANDROID_LOG_WRAP_DEFAULT_TIMEOUT 7200 /* 2 hour default */
#endif
#if __ANDROID_USE_LIBLOG_READER_INTERFACE > 1
#define ANDROID_LOG_PSTORE   0x80000000
#endif

struct logger_list* android_logger_list_alloc(int mode,
                                              unsigned int tail,
                                              pid_t pid);
struct logger_list* android_logger_list_alloc_time(int mode,
                                                   log_time start,
                                                   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

#endif /* __ANDROID_USE_LIBLOG_READER_INTERFACE */

#ifdef __cplusplus
}
#endif

#endif /* _LIBS_LOG_LOG_H */