#!/usr/bin/perl
#
# Copyright (C) 2011-2012 Red Hat, Inc.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library.  If not, see
# <http://www.gnu.org/licenses/>.
#
# Author: Daniel P. Berrange <berrange@redhat.com>
#
# Generate a set of systemtap probe definitions corresponding to
# DTrace probe markers in libvirt.so
#
#  perl dtrace2systemtap.pl probes.d > libvirt_probes.stp
#

use strict;
use warnings;

my $file;
my @files;
my %files;

my $with_modules = 0;
if ($ARGV[0] eq "--with-modules") {
    # set if we want to honor the "module" setting in the .d file
    $with_modules = 1;
    shift @ARGV;
}

my $bindir = shift @ARGV;
my $sbindir = shift @ARGV;
my $libdir = shift @ARGV;

my $probe;
my $args;

# Read the DTraceprobes definition
while (<>) {
    next if m,^\s*$,;

    next if /^\s*provider\s+\w+\s*{\s*$/;
    next if /^\s*};\s*$/;

    if (m,^\s*\#,) {
        if (m,^\s*\#\s*file:\s*(\S+)\s*$,) {
            $file = $1;
            push @files, $file;
            $files{$file} = { prefix => undef, probes => [] };
        } elsif (m,^\s*\#\s*prefix:\s*(\S+)\s*$,) {
            $files{$file}->{prefix} = $1;
        } elsif (m,^\s*\#\s*binary:\s*(\S+)\s*$,) {
            $files{$file}->{binary} = $1;
        } elsif (m,^\s*\#\s*module:\s*(\S+)\s*$,) {
            $files{$file}->{module} = $1;
        } else {
            # ignore unknown comments
        }
    } else {
        if (m,\s*probe\s+([a-zA-Z0-9_]+)\((.*?)(\);)?$,) {
            $probe = $1;
            $args = $2;
            if ($3) {
                push @{$files{$file}->{probes}}, [$probe, $args];
                $probe = $args = undef;
            }
        } elsif ($probe) {
            if (m,^(.*?)(\);)?$,) {
                $args .= $1;
                if ($2) {
                    push @{$files{$file}->{probes}}, [$probe, $args];
                    $probe = $args = undef;
                }
            } else {
                die "unexpected data $_ on line $.";
            }
        } else {
            die "unexpected data $_ on line $.";
        }
    }
}

# Write out the SystemTap probes
foreach my $file (@files) {
    my $prefix = $files{$file}->{prefix};
    my @probes = @{$files{$file}->{probes}};

    print "# $file\n\n";
    foreach my $probe (@probes) {
        my $name = $probe->[0];
        my $args = $probe->[1];

        my $pname = $name;
        $pname =~ s/${prefix}_/libvirt.$prefix./;

        my $binary = "$libdir/libvirt.so";
        if (exists $files{$file}->{binary}) {
            $binary = $sbindir . "/" . $files{$file}->{binary};
        }
        if ($with_modules && exists $files{$file}->{module}) {
            $binary = $libdir . "/" . $files{$file}->{module};
        }

        print "probe $pname = process(\"$binary\").mark(\"$name\") {\n";

        my @args = split /,/, $args;
        for (my $i = 0 ; $i <= $#args ; $i++) {
            my $arg = $args[$i];
            my $isstr = $arg =~ /char\s+\*/;
            $arg =~ s/^.*\s\*?(\S+)$/$1/;

            if ($isstr) {
                print "  $arg = user_string(\$arg", $i + 1, ");\n";
            } else {
                print "  $arg = \$arg", $i + 1, ";\n";
            }
        }
        print "}\n\n";
    }
    print "\n";
}