gen-dtrace-probe-header

#!/usr/bin/env perl

use strict;
use warnings;

use Getopt::Std;

my %opts;
getopts("o:", \%opts);

my $outfile = $opts{o} || "/dev/stdout";

my $infile = shift;
if (!$infile) {
    die "No input dtrace provider file specified\n";
}

open my $in, $infile or
    die "Cannot open $infile for reading: $!\n";

my $src = do { local $/; <$in> };

close $in;

my ($provider, $modname);
if ($src =~ /\bprovider \s+ (nginx_(\w+))/xs) {
    $provider = $1;
    $modname = $2;

} else {
    die "failed to extrace provider name from $infile\n";
}

my $modname_uc = uc($modname);
my $buf = <<_EOC_;
/*
 * automatically generated from the file $infile by the
 *  gen-dtrace-probe-header tool in the nginx-devel-utils project:
 *  https://github.com/agentzh/nginx-devel-utils
 */

#ifndef _NGX_HTTP_${modname_uc}_PROBE_H_INCLUDED_
#define _NGX_HTTP_${modname_uc}_PROBE_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>


#if defined(NGX_DTRACE) && NGX_DTRACE

#include <ngx_dtrace_provider.h>

_EOC_

my @defs;

while ($src =~ /^ \s* probe \s+ (\w+) \s* \( ([^\)]*) \) \s* ; \s* $/xogms) {
    my ($probe, $args) = ($1, $2);
    $args =~ s/\n/ /g;
    $args =~ s/  +/ /g;
    $args =~ s{/\* .*? \*/}{}xg;
    my @args = split /\s*,\s*/, $args;
    my @arg_names;
    for my $arg (@args) {
        if ($arg =~ /\w+$/) {
            push @arg_names, $&;

        } else {
            die "failed to extract argument name from the argument specifier $arg in probe $probe\n";
        }
    }

    my $dtrace_macro = $provider . "_" . $probe;
    for ($dtrace_macro) {
        s/__+/_/g;
        $_ = uc;
    }

    my $nginx_macro = $probe;
    for ($nginx_macro) {
        s/__+/_/g;
        s/^http_${modname}_//;
    }

    $nginx_macro = "ngx_http_${modname}_probe_$nginx_macro";

    #warn "probe: $probe (dtrace $dtrace_macro, nginx $nginx_macro), args: @arg_names\n";

    push @defs, {
        dtrace_macro => $dtrace_macro,
        nginx_macro => $nginx_macro,
        args => \@arg_names,
    };
}

for my $def (@defs) {
    my $nginx_macro = $def->{nginx_macro};
    my $dtrace_macro = $def->{dtrace_macro};
    my @args = @{ $def->{args} };
    my $arglist = join ", ", @args;

    my $s = "#define $nginx_macro($arglist)";
    $s .= (" " x (77 - length $s)) . "\\\n";
    $s .= "    $dtrace_macro($arglist)\n\n";
    $buf .= $s;
}

$buf .= "#else /* !(NGX_DTRACE) */\n\n";

for my $def (@defs) {
    my $nginx_macro = $def->{nginx_macro};
    my $dtrace_macro = $def->{dtrace_macro};
    my @args = @{ $def->{args} };
    my $arglist = join ", ", @args;

    $buf .= "#define $nginx_macro($arglist)\n";
}

$buf .= "\n#endif\n\n#endif /* _NGX_HTTP_${modname_uc}_PROBE_H_INCLUDED_ */\n";

open my $out, ">$outfile"
    or die "Cannot open $outfile for writing: $!\n";
print $out $buf;
close $out;