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✏️ Editing: cpuser_service_manager

#!/usr/local/cpanel/3rdparty/bin/perl

# cpanel - scripts/cpuser_service_manager          Copyright 2022 cPanel, L.L.C.
#                                                           All rights reserved.
# copyright@cpanel.net                                         http://cpanel.net
# This code is subject to the cPanel license. Unauthorized copying is prohibited

use strict;
use warnings;

package scripts::cpuser_service_manager;

use App::CmdDispatch;

my $cmds = {
    add => {
        code     => \&add,
        clue     => "add <service_name> --init-script=<ABS_PATH> (or --ubic-service=<ABS_PATH>)",
        abstract => "Setup a service",
        help     => "Setup the given user managed and monitored service",
    },
    rem => {
        code     => \&rem,
        clue     => "rem <service_name>",
        abstract => "Remove a service",
        help     => "Remove the given user managed and monitored service",
    },
    list => {
        code     => \&list,
        clue     => "list",
        abstract => "List your services",
        help     => "List your user managed and monitored services",
    },
    info => {
        code     => sub { my ( $app, @args ) = @_; die "too many arguments\n" if @args; print <DATA> },    # simplify PATH info w/ CPANEL-22345 fix when available
        clue     => "info",
        abstract => "Info on this tool/feature",
        help     => "Information about how this works and what you can do after a service is added",
    },
};

my $hint_blurb = "This tool supports the following commands (i.e. $0 {command} …):";
my $opts       = {
    'help:pre_hint'  => $hint_blurb,
    'help:pre_help'  => "Add/Remove/List user managed and monitored services.\n\n$hint_blurb",
    default_commands => "help",
    alias            => { remove => "rem" },
};

run(@ARGV) if !caller;

sub run {
    my (@argv) = @_;
    local $ENV{TERM} = $ENV{TERM} || "xterm-256color";    # non-CLI modulino avoid needless: Cannot find termcap: TERM not set at …/Term/ReadLine.pm line 373.
    return App::CmdDispatch->new( $cmds, $opts )->run(@argv);
}

################
#### commands ##
################

sub add {
    my ( $app, $service_name, @flags ) = @_;

eval {
        require Ubic;                                # this means ubic-admin is installed
        require Ubic::Service::InitScriptWrapper;    # this means the --init-script setup will work
    };
    if ($@) {
        die "Ubic must be installed to add a service!\n";
    }

$service_name = _validated_service_name( $app, $service_name );

my $service_dir = _get_service_dir();

if ( -l "$service_dir/$service_name" || -e _ ) {
        die "The “$service_name” service already exists.\n";
    }

# Tiny race here w/ worst case being an error or they over write a file that they just wrote, so no biggy  ¯\_(ツ)_/¯

my $opts = _validated_add_flags( $app, @flags );

# would be cool if Cpanel::FindBin (or whatever) did this for us: CPANEL-22345
    my $real_perl  = readlink("/usr/local/cpanel/3rdparty/bin/perl");
    my $cp_bin_dir = $real_perl;
    $cp_bin_dir =~ s{/perl$}{};
    local $ENV{PATH} = "$cp_bin_dir:$ENV{PATH}";    # not only does this allow it to find our ubic-admin, it allows its env-shebang to pick up our perl

my $orig_umask = umask(0027);
    system("ubic-admin setup --batch-mode --local --no-sticky-777") && die "Could not ensure base ubic configuration: $?\n";    # idempotent
    _cpanelify_ubic_watchdog_cron();
    _prepend_comment_to_ubic_cnf();

if ( $opts->{type} eq 'init' ) {
        _setup_init( $opts->{path}, $service_dir, $service_name );
    }
    elsif ( $opts->{type} eq "ubic" ) {
        symlink( $opts->{path}, "$service_dir/$service_name" ) or die "Could not create “$opts->{path}”: $!\n";
    }
    else {
        umask($orig_umask);
        _bail( $app, "Something is wrong …" );    # juuuust in case we add a bug …
    }

umask($orig_umask);
    return;
}

sub rem {
    my ( $app, $service_name ) = @_;
    $service_name = _validated_service_name( $app, $service_name );

my $service_dir  = _get_service_dir();
    my $service_file = "$service_dir/$service_name";

if ( !-e $service_file ) {
        print "The “$service_name” service does not exist.\n";
        return 1;
    }
    else {
        print "Removing “$service_name” service …\n";
        unlink($service_file);
        if ( -e $service_file ) {
            die "Failed to delete “$service_file”: $!\n";
        }
        return 1;
    }

return;
}

sub list {
    my ($app) = @_;
    _bail( $app, "“list” does not take any arguments" ) if @_ > 1;

my $service_dir = _get_service_dir();
    return if !-d $service_dir;
    opendir( my $dh, $service_dir ) or die "Could not readdir “$service_dir”: $!\n";

for my $service ( sort readdir($dh) ) {
        next if $service eq '.' || $service eq '..';
        print "$service\n";
    }

closedir($dh);

return;
}

###############
#### helpers ##
###############

sub _get_cmd {
    return $cmds;
}

sub _bail {
    my ( $app, $msg ) = @_;
    chomp($msg);

die "$msg\n" if $ENV{ __PACKAGE__ . "::bail_die" };    # for API calls, otherwise:

warn "$msg\n";
    $app->help();
    exit(1);                                               # there is no return()ing from this lol
}

sub _prepend_comment_to_ubic_cnf {

# comments crate uninit warnings in ubic's conf parser :/
    my $ubic_comment  = "IMPORTANT = Do not edit this cPanel User Service Manager generated file!";
    my $ubic_cnf_path = _get_homedir() . "/.ubic.cfg";

require Cpanel::LoadFile;
    my $ubic_cnf = Cpanel::LoadFile::load($ubic_cnf_path);
    if ( open my $fh, '>', $ubic_cnf_path ) {
        print {$fh} "$ubic_comment\n";
        print {$fh} $ubic_cnf;
        close $fh;
    }
    else {
        warn "Could not prepend “ubic_comment” line to $ubic_cnf_path: $!\n";
    }

return;
}

sub _cpanelify_ubic_watchdog_cron {

# Cpanel::Cron::Utils::run_crontab(): does not work under jailshell, and can't - under normal shell
    my @crontab = `crontab -l`;
    return if !@crontab;

for my $line (@crontab) {
        if ( $line =~ m/ubic-watchdog ubic\.watchdog/ ) {
            $line = "\n# Do not edit the cPanel User Service Manager generated cronjob for Ubic!\n";    # any changes need synced w/ Whostmgr/Accounts/Modify.pm, specifically _update_ubic_conf()
            $line .= '* * * * * PATH=$(dirname $(readlink /usr/local/cpanel/3rdparty/bin/perl)):$PATH ubic-watchdog ubic.watchdog >>$HOME/ubic/log/watchdog.log 2>>$HOME/ubic/log/watchdog.err.log';
            $line .= "\n\n";
        }
    }

return _write_crontab_lines( \@crontab );
}

sub _write_crontab_lines {
    my ($crontab_ar) = @_;

open my $fh, '|-', 'crontab -' or die "Can't run 'crontab -': $!\n";
    print {$fh} @{$crontab_ar} or die "Can't write to crontab pipe: $!\n";
    close $fh                  or die "Can't close crontab pipe: $!\n";

return 1;
}

sub _get_homedir {
    return ( getpwuid($>) )[7];
}

sub _get_service_dir {
    my $homedir = _get_homedir();
    return "$homedir/ubic/service";    # TODO: get from $homedir/.ubic.cfg {service_dir} if set
}

sub _validated_service_name {
    my ( $app, $service_name ) = @_;

if ( !defined $service_name || $service_name !~ m/^[\w-]+(?:\.[\w-]+)*$/ ) {    # regexp is $service_name_re from Ubic.pm v1.60
        _bail( $app, "Invalid service name" );
    }

return $service_name;
}

sub _validated_add_flags {
    my ( $app, @flags ) = @_;
    _bail( $app, "too many arguments" ) if @flags > 1;

if ( $flags[0] =~ m/^--init-script=(.+)/ ) {
        my $init = $1;
        _check_path( $app, "--init-script", $init );
        return { path => $init, type => "init" };
    }
    elsif ( $flags[0] =~ m/^--ubic-service=(.+)/ ) {
        my $ubic = $1;
        _check_path( $app, "--ubic-service", $ubic );
        return { path => $ubic, type => "ubic" };
    }
    else {
        _bail( $app, "--init-script or --ubic-service is required" );
    }

return;
}

sub _check_path {
    my ( $app, $flag, $path ) = @_;

if ( $path !~ m{^/} ) {
        _bail( $app, "$flag value must be an absolute path" );
    }

if ( !-e $path || !-r $path ) {
        _bail( $app, "$flag value does not exist or is not readable" );
    }

return;
}

sub _setup_init {
    my ( $abs_path_to_init, $service_dir, $service_name ) = @_;

if ( open my $fh, ">", "$service_dir/$service_name" ) {
        my $abs_path_to_init_escaped = $abs_path_to_init;
        $abs_path_to_init_escaped =~ s/'/\\'/g;

my $created_by_init_file_flag_value = $abs_path_to_init ne $abs_path_to_init_escaped ? "'$abs_path_to_init_escaped'" : $abs_path_to_init;

print {$fh} <<"END_UBIC_SERVICE_FILE";
# Created by `$0 add $service_name --init-file=$created_by_init_file_flag_value`
use Ubic::Service::InitScriptWrapper;
Ubic::Service::InitScriptWrapper->new('$abs_path_to_init_escaped');
END_UBIC_SERVICE_FILE

print "Installed “$service_name” service.\n";
        return 1;
    }
    else {
        die "Could not create “$service_dir/$service_name”: $!\n";
    }

return;
}

__DATA__
____
A cPanel user managed and monitored service allows users to run daemons as themselves.

Aside from security benefits it is very convenient. The subsystem used to accomplish this is known as Ubic (a “polymorphic service manager”).

This script will setup ubic on your account (if its not already) which includes setting up ~/ubic, ~/.ubic.cfg (do not edit this or things will not work correctly), and a cronjob for a ubic watchdog process that will monitor your service (e.g. to restart it if it stops running or isn’t running because the server just rebooted).

After you have a service setup you can manage it manually w/ the `ubic` command, the most common commands are:

`ubic status <service_name>`
    `ubic start <service_name>`
    `ubic stop <service_name>`
    `ubic restart <service_name>`

There are others, `man ubic` for details.

Note: If `ubic` is not in your PATH you will need to add it. For example, if you use BASH you could add this to your .bashrc:

export PATH=$(dirname $(readlink /usr/local/cpanel/3rdparty/bin/perl)):$PATH

This script supports two types of approaches:

1. An existing init script

This allows you to turn any LSB-compliant init script into a user managed and monitored service.

2. An existing ubic service file.

This allows you to do things however you like using Ubic::Service based scripts.

An example to get you started is the SYNOPSIS for a PSGI based app running under Starman: https://metacpan.org/pod/Ubic::Service::Starman

Let’s say you have an app installed in ~/apps/foo/ and that has ~/apps/foo/bin/ubic.service that uses Ubic::Service::Starman.

All you have to do is run `$0 add foo --ubic-service=~/apps/foo/bin/ubic.service` and voilà it is ready to go!

Since, in this case, the ubic entry is a symlink the application can update it code and everything will just keep working!
––––

MR SKB