stracelike

#! /usr/bin/env perl

# Copyright (C) YangBingwu (detailyang)

use 5.006001;
use strict;
use warnings;
use Getopt::Std qw ( getopts );

sub usage();

my %opts;

getopts("a:t:hp:d", \%opts) or die usage();

if ($opts{h}) {
    print usage();
    exit;
}

my $stap_args = $opts{a} || '';

my $pid = $opts{p}
    or die "No -p option specify\n";

if ($pid !~ /^\d+$/) {
   die "Bad -p options value \"$pid\": not look like pid";
}

my $time = $opts{t} || 20000;

if ($time !~ /^\d+$/) {
   die "Bad -t options value \"$time\": not look like time";
}


my $preamble = <<_EOS_;
global thread_args%
global thread_t%
global blacklist[2]

probe begin {
    /* list those syscalls that never .return */
    blacklist["exit"]=1
    blacklist["exit_group"]=1

    warn("stracing syscall")
}
_EOS_

my $stap_src = <<_EOS_;
$preamble

probe nd_syscall.* {
    if (pid() != target()) next

    now = gettimeofday_us()

    if (name in blacklist) {
        prefix = sprintf("%s[%d] %s.%06d ", execname(), pid(), ctime(now/1000000), now%1000000)
        printf("%s %s(%s)\\n", prefix, name, argstr)
        next
    }

    thread_t[pid()] = now
    thread_args[pid()] = argstr
}

probe nd_syscall.*.return {
    if (pid() != target()) next

    now = gettimeofday_us()
    last = thread_t[pid()]
    argstr = thread_args[pid()]

    if (last) {
        diff = now -last
        prefix = sprintf("%s.%06d ", ctime(last/1000000), last%1000000)
        suffix = sprintf(" <%d.%06d>", diff/1000000, diff%1000000)
        printf("%s %s(%s) = %s%s\\n", prefix, name, argstr, retstr, suffix)
    }

    delete thread_t[pid()]
    delete thread_args[pid()]
}

probe timer.ms($time) {
    exit()
}
_EOS_

if ($opts{d}) {
    print $stap_src;
    exit;
}

open my $in, "| stap --skip-badvars -x $pid $stap_args -";

print $in $stap_src;

close $in;

sub usage() {
    return <<'_EOS_';
Usage:
    stracelike [optoins]

Options:
    -a <args>           Pass extra arguments to the stap utility.
    -d                  Dump out the systemtap script source.
    -h                  Print this usage.
    -p <pid>            Specify the user process pid.
    -t <seconds>        Specify the number of seconds for sampling.

Examples:
    stracelike -p 12345 -t 10000
_EOS_
}