path: root/IkiWiki/Wrapper.pm

#!/usr/bin/perl

use warnings;
use strict;
use Cwd q{abs_path};
use Data::Dumper;
use IkiWiki;

package IkiWiki;

sub gen_wrapper () { #{{{
    $config{srcdir}=abs_path($config{srcdir});
    $config{destdir}=abs_path($config{destdir});
    my $this=abs_path($0);
    if (! -x $this) {
        error("$this doesn't seem to be executable");
    }

    if ($config{setup}) {
        error("cannot create a wrapper that uses a setup file");
    }
    my $wrapper=possibly_foolish_untaint($config{wrapper});
    if (! defined $wrapper || ! length $wrapper) {
        error("wrapper filename not specified");
    }
    delete $config{wrapper};
    
    my @envsave;
    push @envsave, qw{REMOTE_ADDR QUERY_STRING REQUEST_METHOD REQUEST_URI
                   CONTENT_TYPE CONTENT_LENGTH GATEWAY_INTERFACE
               HTTP_COOKIE REMOTE_USER} if $config{cgi};
    my $envsave="";
    foreach my $var (@envsave) {
        $envsave.=<<"EOF"
    if ((s=getenv("$var")))
        asprintf(&newenviron[i++], "%s=%s", "$var", s);
EOF
    }
    if ($config{rcs} eq "svn" && $config{notify}) {
        # Support running directly as hooks/post-commit by passing
        # $2 in REV in the environment.
        $envsave.=<<"EOF"
    if (argc == 3)
        asprintf(&newenviron[i++], "REV=%s", argv[2]);
    else if ((s=getenv("REV")))
        asprintf(&newenviron[i++], "%s=%s", "REV", s);
EOF
    }
    if ($config{rcs} eq "tla" && $config{notify}) {
        $envsave.=<<"EOF"
    if ((s=getenv("ARCH_VERSION")))
        asprintf(&newenviron[i++], "%s=%s", "ARCH_VERSION", s);
EOF
    }
    
    $Data::Dumper::Indent=0; # no newlines
    my $configstring=Data::Dumper->Dump([\%config], ['*config']);
    $configstring=~s/\\/\\\\/g;
    $configstring=~s/"/\\"/g;
    $configstring=~s/\n/\\\n/g;
    
    open(OUT, ">$wrapper.c") || error("failed to write $wrapper.c: $!");;
    print OUT <<"EOF";
/* A wrapper for ikiwiki, can be safely made suid. */
#define _GNU_SOURCE
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

extern char **environ;

int main (int argc, char **argv) {
    /* Sanitize environment. */
    char *s;
    char *newenviron[$#envsave+5];
    int i=0;
$envsave
    newenviron[i++]="HOME=$ENV{HOME}";
    newenviron[i++]="WRAPPED_OPTIONS=$configstring";
    newenviron[i]=NULL;
    environ=newenviron;

    if (setregid(getegid(), -1) != 0 || setreuid(geteuid(), -1) != 0) {
        perror("failed to drop real uid/gid");
        exit(1);
    }

    execl("$this", "$this", NULL);
    perror("failed to run $this");
    exit(1);
}
EOF
    close OUT;
    if (system("gcc", "$wrapper.c", "-o", $wrapper) != 0) {
        error("failed to compile $wrapper.c");
    }
    unlink("$wrapper.c");
    if (defined $config{wrappermode} &&
        ! chmod(oct($config{wrappermode}), $wrapper)) {
        error("chmod $wrapper: $!");
    }
    print "successfully generated $wrapper\n";
} #}}}

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