#!/usr/bin/env python
#
# syscount   Summarize syscall counts and latencies.
#
# USAGE: syscount [-p PID] [-i INTERVAL] [-T TOP] [-x] [-L] [-m] [-P] [-l]
#
# Copyright 2017, Sasha Goldshtein.
# Licensed under the Apache License, Version 2.0 (the "License")
#
# 15-Feb-2017   Sasha Goldshtein    Created this.

from time import sleep, strftime
import argparse
import errno
import itertools
import sys
import signal
from bcc import BPF
from bcc.utils import printb
from bcc.syscall import syscall_name

if sys.version_info.major < 3:
    izip_longest = itertools.izip_longest
else:
    izip_longest = itertools.zip_longest

# signal handler
def signal_ignore(signal, frame):
    print()

def handle_errno(errstr):
    try:
        return abs(int(errstr))
    except ValueError:
        pass

    try:
        return getattr(errno, errstr)
    except AttributeError:
        raise argparse.ArgumentTypeError("couldn't map %s to an errno" % errstr)


parser = argparse.ArgumentParser(
    description="Summarize syscall counts and latencies.")
parser.add_argument("-p", "--pid", type=int, help="trace only this pid")
parser.add_argument("-i", "--interval", type=int,
    help="print summary at this interval (seconds)")
parser.add_argument("-d", "--duration", type=int,
    help="total duration of trace, in seconds")
parser.add_argument("-T", "--top", type=int, default=10,
    help="print only the top syscalls by count or latency")
parser.add_argument("-x", "--failures", action="store_true",
    help="trace only failed syscalls (return < 0)")
parser.add_argument("-e", "--errno", type=handle_errno,
    help="trace only syscalls that return this error (numeric or EPERM, etc.)")
parser.add_argument("-L", "--latency", action="store_true",
    help="collect syscall latency")
parser.add_argument("-m", "--milliseconds", action="store_true",
    help="display latency in milliseconds (default: microseconds)")
parser.add_argument("-P", "--process", action="store_true",
    help="count by process and not by syscall")
parser.add_argument("-l", "--list", action="store_true",
    help="print list of recognized syscalls and exit")
parser.add_argument("--ebpf", action="store_true",
    help=argparse.SUPPRESS)
args = parser.parse_args()
if args.duration and not args.interval:
    args.interval = args.duration
if not args.interval:
    args.interval = 99999999

if args.list:
    for grp in izip_longest(*(iter(sorted(syscalls.values())),) * 4):
        print("   ".join(["%-20s" % s for s in grp if s is not None]))
    sys.exit(0)

text = """
#ifdef LATENCY
struct data_t {
    u64 count;
    u64 total_ns;
};

BPF_HASH(start, u64, u64);
BPF_HASH(data, u32, struct data_t);
#else
BPF_HASH(data, u32, u64);
#endif

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

#ifdef FILTER_PID
    if (pid_tgid >> 32 != FILTER_PID)
        return 0;
#endif

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

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

#ifdef FILTER_PID
    if (pid_tgid >> 32 != FILTER_PID)
        return 0;
#endif

#ifdef FILTER_FAILED
    if (args->ret >= 0)
        return 0;
#endif

#ifdef FILTER_ERRNO
    if (args->ret != -FILTER_ERRNO)
        return 0;
#endif

#ifdef BY_PROCESS
    u32 key = pid_tgid >> 32;
#else
    u32 key = args->id;
#endif

#ifdef LATENCY
    struct data_t *val, zero = {};
    u64 *start_ns = start.lookup(&pid_tgid);
    if (!start_ns)
        return 0;

    val = data.lookup_or_init(&key, &zero);
    val->count++;
    val->total_ns += bpf_ktime_get_ns() - *start_ns;
#else
    u64 *val, zero = 0;
    val = data.lookup_or_init(&key, &zero);
    ++(*val);
#endif
    return 0;
}
"""

if args.pid:
    text = ("#define FILTER_PID %d\n" % args.pid) + text
if args.failures:
    text = "#define FILTER_FAILED\n" + text
if args.errno:
    text = "#define FILTER_ERRNO %d\n" % abs(args.errno) + text
if args.latency:
    text = "#define LATENCY\n" + text
if args.process:
    text = "#define BY_PROCESS\n" + text
if args.ebpf:
    print(text)
    exit()

bpf = BPF(text=text)

def print_stats():
    if args.latency:
        print_latency_stats()
    else:
        print_count_stats()

agg_colname = "PID    COMM" if args.process else "SYSCALL"
time_colname = "TIME (ms)" if args.milliseconds else "TIME (us)"

def comm_for_pid(pid):
    try:
        return open("/proc/%d/comm" % pid, "rb").read().strip()
    except Exception:
        return b"[unknown]"

def agg_colval(key):
    if args.process:
        return b"%-6d %-15s" % (key.value, comm_for_pid(key.value))
    else:
        return syscall_name(key.value)

def print_count_stats():
    data = bpf["data"]
    print("[%s]" % strftime("%H:%M:%S"))
    print("%-22s %8s" % (agg_colname, "COUNT"))
    for k, v in sorted(data.items(), key=lambda kv: -kv[1].value)[:args.top]:
        if k.value == 0xFFFFFFFF:
            continue    # happens occasionally, we don't need it
        printb(b"%-22s %8d" % (agg_colval(k), v.value))
    print("")
    data.clear()

def print_latency_stats():
    data = bpf["data"]
    print("[%s]" % strftime("%H:%M:%S"))
    print("%-22s %8s %16s" % (agg_colname, "COUNT", time_colname))
    for k, v in sorted(data.items(),
                       key=lambda kv: -kv[1].total_ns)[:args.top]:
        if k.value == 0xFFFFFFFF:
            continue    # happens occasionally, we don't need it
        printb((b"%-22s %8d " + (b"%16.6f" if args.milliseconds else b"%16.3f")) %
               (agg_colval(k), v.count,
                v.total_ns / (1e6 if args.milliseconds else 1e3)))
    print("")
    data.clear()

print("Tracing %ssyscalls, printing top %d... Ctrl+C to quit." %
      ("failed " if args.failures else "", args.top))
exiting = 0 if args.interval else 1
seconds = 0
while True:
    try:
        sleep(args.interval)
        seconds += args.interval
    except KeyboardInterrupt:
        exiting = 1
        signal.signal(signal.SIGINT, signal_ignore)
    if args.duration and seconds >= args.duration:
        exiting = 1

    print_stats()

    if exiting:
        print("Detaching...")
        exit()