// Copyright 2017, Sasha Goldshtein.
// Licensed under the Apache License, Version 2.0 (the "License")

DEFINE_DETAILS
DEFINE_LATENCY

struct key_t {
    u32 pid;
    u32 id;
};

BPF_ARRAY(stats, u64, NR_SYSCALLS);
#ifdef LATENCY
BPF_ARRAY(latstats, u64, NR_SYSCALLS);
BPF_HASH(start, u64, u64);
#endif

#ifdef DETAILS
BPF_HASH(pidstats, struct key_t, u64, MAX_PIDS * NR_SYSCALLS);
#ifdef LATENCY
BPF_HASH(pidlatstats, struct key_t, u64, MAX_PIDS * NR_SYSCALLS);
#endif
#endif

#ifdef LATENCY
TRACEPOINT_PROBE(raw_syscalls, sys_enter) {
    u64 pid = bpf_get_current_pid_tgid();

    FILTER_PID

    u64 t = bpf_ktime_get_ns();
    start.update(&pid, &t);
    return 0;
}
#endif

TRACEPOINT_PROBE(raw_syscalls, sys_exit) {
    u64 pid = bpf_get_current_pid_tgid();

    FILTER_PID

    //FILTER_FAILED
    //FILTER_ERRNO

    u32 id = args->id;
    if (id > NR_SYSCALLS) return 0;
    u64 *val = stats.lookup(&id);
    if (val) (*val)++;
#ifdef DETAILS
    u64 zero = 0;
    struct key_t key = {.pid = pid >> 32, .id = id};
    val = pidstats.lookup_or_init(&key, &zero);
    if (val) {
        ++(*val);
    }
#endif
#ifdef LATENCY
    u64 *start_ns = start.lookup(&pid);
    if (!start_ns)
        return 0;
    start.delete(&pid);
    u64 time_ns = bpf_ktime_get_ns() - *start_ns;

    val = latstats.lookup(&id);
    if (val) (*val) += time_ns;
#ifdef DETAILS
    val = pidlatstats.lookup_or_init(&key, &zero);
    if (val) (*val) += time_ns;
#endif
#endif

    return 0;
}