/*
 *  Copyright 2018 Google, Inc
 *
 *  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 _STATSLOG_H_
#define _STATSLOG_H_

#include <assert.h>
#include <inttypes.h>
#include <stats_event_list.h>
#include <stdbool.h>
#include <sys/cdefs.h>

#include <cutils/properties.h>

__BEGIN_DECLS

struct memory_stat {
    int64_t pgfault;
    int64_t pgmajfault;
    int64_t rss_in_bytes;
    int64_t cache_in_bytes;
    int64_t swap_in_bytes;
    int64_t process_start_time_ns;
};

struct kernel_poll_info {
    int poll_fd;
    void (*handler)(int poll_fd);
};

/*
 * These are defined in
 * http://cs/android/frameworks/base/cmds/statsd/src/atoms.proto
 */
#define LMK_KILL_OCCURRED 51
#define LMK_STATE_CHANGED 54
#define LMK_STATE_CHANGE_START 1
#define LMK_STATE_CHANGE_STOP 2

#ifdef LMKD_LOG_STATS

/*
 * The single event tag id for all stats logs.
 * Keep this in sync with system/core/logcat/event.logtags
 */
const static int kStatsEventTag = 1937006964;

void statslog_init();

void statslog_destroy();

#define MEMCG_PROCESS_MEMORY_STAT_PATH "/dev/memcg/apps/uid_%u/pid_%u/memory.stat"
#define PROC_STAT_FILE_PATH "/proc/%d/stat"
#define PROC_STAT_BUFFER_SIZE 1024
#define BYTES_IN_KILOBYTE 1024

/**
 * Logs the change in LMKD state which is used as start/stop boundaries for logging
 * LMK_KILL_OCCURRED event.
 * Code: LMK_STATE_CHANGED = 54
 */
int
stats_write_lmk_state_changed(int32_t code, int32_t state);

/**
 * Logs the event when LMKD kills a process to reduce memory pressure.
 * Code: LMK_KILL_OCCURRED = 51
 */
int
stats_write_lmk_kill_occurred(int32_t code, int32_t uid,
                              char const* process_name, int32_t oom_score, int32_t min_oom_score,
                              int tasksize, struct memory_stat *mem_st);

struct memory_stat *stats_read_memory_stat(bool per_app_memcg, int pid, uid_t uid);

/**
 * Registers a process taskname by pid, while it is still alive.
 */
void stats_store_taskname(int pid, const char* taskname, int poll_fd);

/**
 * Unregister all process tasknames.
 */
void stats_purge_tasknames();

/**
 * Unregister a process taskname, e.g. after it has been killed.
 */
void stats_remove_taskname(int pid, int poll_fd);

bool init_poll_kernel(struct kernel_poll_info *poll_info);

#else /* LMKD_LOG_STATS */

static inline void statslog_init() {}
static inline void statslog_destroy() {}

static inline int
stats_write_lmk_state_changed(int32_t code __unused, int32_t state __unused) { return -EINVAL; }

static inline int
stats_write_lmk_kill_occurred(int32_t code __unused, int32_t uid __unused,
                              char const* process_name __unused, int32_t oom_score __unused,
                              int32_t min_oom_score __unused, int tasksize __unused,
                              struct memory_stat *mem_st __unused) { return -EINVAL; }

static inline struct memory_stat *stats_read_memory_stat(bool per_app_memcg __unused,
                                    int pid __unused, uid_t uid __unused) { return NULL; }

static inline void stats_store_taskname(int pid __unused, const char* taskname __unused,
                                        int poll_fd __unused) {}

static inline void stats_purge_tasknames() {}

static inline void stats_remove_taskname(int pid __unused, int poll_fd __unused) {}

static inline bool init_poll_kernel(struct kernel_poll_info *poll_info __unused) { return false; }

#endif /* LMKD_LOG_STATS */

__END_DECLS

#endif /* _STATSLOG_H_ */