use $mirror instead of $path in calling system(gunzip)

[cheng]

I am getting the following errors when running

sudo -u apt-mirror apt-mirror

Processing indexes: [
Psh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty/main/binary-amd64/Packages: Permission denied
sh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty/restricted/binary-amd64/Packages: Permission denied
Psh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty-security/main/binary-amd64/Packages: Permission denied
sh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty-security/restricted/binary-amd64/Packages: Permission denied
Psh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty-updates/main/binary-amd64/Packages: Permission denied
sh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty-updates/restricted/binary-amd64/Packages: Permission denied
Psh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty-backports/main/binary-amd64/Packages: Permission denied
sh: 1: cannot create archive.ubuntu.com/ubuntu//dists/trusty-backports/restricted/binary-amd64/Packages: Permission denied
]

After looking at the source code, I believe the following code fragment inside "process_index_gz" should be the following:

    if ( $index =~ s/\.gz$// )
    {
        system("gunzip < $mirror$index.gz > $mirror$index");
        print "done!\n";
    }

instead of the original:

    if ( $index =~ s/\.gz$// )
    {
        system("gunzip < $path/$index.gz > $path/$index");
        print "done!\n";
    }

Since $path despite its name came from:

    $path = sanitise_uri($uri);

and $mirror came from:

    $mirror = get_variable("mirror_path") . "/" . $path;

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: apt-mirror 0.5.1-1ubuntu1 [modified: usr/bin/apt-mirror]
ProcVersionSignature: Ubuntu 4.4.0-98.121-generic 4.4.90
Uname: Linux 4.4.0-98-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
Date: Sun Nov 5 22:11:54 2017
InstallationDate: Installed on 2017-11-04 (1 days ago)
InstallationMedia: Ubuntu-Server 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: apt-mirror
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.cron.d.apt-mirror:
 #
 # Regular cron jobs for the apt-mirror package
 #
 0 4 * * * apt-mirror /usr/bin/apt-mirror > /var/spool/apt-mirror/var/cron.log
mtime.conffile..etc.apt.mirror.list: 2017-11-04T21:42:43.202920
mtime.conffile..etc.cron.d.apt-mirror: 2017-11-05T21:32:52.960585

[Ed Peguillan III (yankee14-ed)]

I am also having this exact bug.