fix NoAccess when inheritred from pool

[pve-access-control.git] / PVE / RPCEnvironment.pm

package PVE::RPCEnvironment;

use strict;
use warnings;
use POSIX qw(:sys_wait_h EINTR);
use IO::Handle;
use IO::File;
use IO::Select;
use Fcntl qw(:flock);
use PVE::Exception qw(raise raise_perm_exc);
use PVE::SafeSyslog;
use PVE::Tools;
use PVE::INotify;
use PVE::Cluster;
use PVE::ProcFSTools;
use PVE::AccessControl;
use CGI;

# we use this singleton class to pass RPC related environment values

my $pve_env;

# save $SIG{CHLD} handler implementation.
# simply set $SIG{CHLD} = $worker_reaper;
# and register forked processes with &$register_worker(pid)
# Note: using $SIG{CHLD} = 'IGNORE' or $SIG{CHLD} = sub { wait (); } or ...
# has serious side effects, because perls built in system() and open()
# functions can't get the correct exit status of a child. So we cant use 
# that (also see perlipc)

my $WORKER_PIDS;

my $log_task_result = sub {
    my ($upid, $user, $status) = @_;

    my $msg = 'successful';
    my $pri = 'info';
    if ($status != 0) {
	my $ec = $status >> 8;
	my $ic = $status & 255;
	$msg = $ec ? "failed ($ec)" : "interrupted ($ic)";
	$pri = 'err';
    }
    my $tlist = active_workers($upid);
    PVE::Cluster::broadcast_tasklist($tlist);
    my $task;
    foreach my $t (@$tlist) {
	if ($t->{upid} eq $upid) {
	    $task = $t;
	    last;
	}
    }
    if ($task && $task->{status}) {
	$msg = $task->{status};
    }
    PVE::Cluster::log_msg($pri, $user, "end task $upid $msg");
};

my $worker_reaper = sub {
    local $!; local $?;
    foreach my $pid (keys %$WORKER_PIDS) {
        my $waitpid = waitpid ($pid, WNOHANG);
        if (defined($waitpid) && ($waitpid == $pid)) {
	    my $info = $WORKER_PIDS->{$pid};
	    if ($info && $info->{upid} && $info->{user}) {
		&$log_task_result($info->{upid}, $info->{user}, $?);
	    }
            delete ($WORKER_PIDS->{$pid});
	}
    }
};

my $register_worker = sub {
    my ($pid, $user, $upid) = @_;

    return if !$pid;

    # do not register if already finished
    my $waitpid = waitpid ($pid, WNOHANG);
    if (defined($waitpid) && ($waitpid == $pid)) {
	delete ($WORKER_PIDS->{$pid});
	return;
    }

    $WORKER_PIDS->{$pid} = {
	user => $user,
	upid => $upid,
    };
};

# ACL cache

my $compile_acl_path = sub {
    my ($self, $user, $path) = @_;

    my $cfg = $self->{user_cfg};

    return undef if !$cfg->{roles};

    die "internal error" if $user eq 'root@pam';

    my $cache = $self->{aclcache};
    $cache->{$user} = {} if !$cache->{$user};
    my $data = $cache->{$user};

    if (!$data->{poolroles}) {
	$data->{poolroles} = {}; 
 
	foreach my $poolpath (keys %{$cfg->{pools}}) {
	    my $d = $cfg->{pools}->{$poolpath};
	    my @ra = PVE::AccessControl::roles($cfg, $user, "/pool$poolpath"); # pool roles
	    next if !scalar(@ra);
	    foreach my $vmid (keys %{$d->{vms}}) {
		for my $role (@ra) {
		    $data->{poolroles}->{"/vms/$vmid"}->{$role} = 1;
		}
	    }
	    foreach my $storeid (keys %{$d->{storage}}) {
		for my $role (@ra) {
		    $data->{poolroles}->{"/storage/$storeid"}->{$role} = 1;
		}
	    }
	}
    }

    my @ra = PVE::AccessControl::roles($cfg, $user, $path);

    # apply roles inherited from pools
    # Note: assume we do not want to propagate those privs
    if ($data->{poolroles}->{$path}) {
	if (!($ra[0] && $ra[0] eq 'NoAccess')) {
	    if ($data->{poolroles}->{$path}->{NoAccess}) {
		@ra = ('NoAccess');
	    } else {
		foreach my $role (keys %{$data->{poolroles}->{$path}}) {
		    push @ra, $role;
		}
	    }
	}
    }

    $data->{roles}->{$path} = [ @ra ];
 
    my $privs = {};
    foreach my $role (@ra) {
	if (my $privset = $cfg->{roles}->{$role}) {
	    foreach my $p (keys %$privset) {
		$privs->{$p} = 1;
	    }
	}
    }
    $data->{privs}->{$path} = $privs;

    return $privs;
};

sub roles {
   my ($self, $user, $path) = @_;

   if ($user eq 'root@pam') { # root can do anything
       return ('Administrator');
   } 

   $user = PVE::AccessControl::verify_username($user, 1);
   return () if !$user;

   my $cache = $self->{aclcache};
   $cache->{$user} = {} if !$cache->{$user};

   my $acl = $cache->{$user};

   my $roles = $acl->{roles}->{$path};
   return @$roles if $roles;

   &$compile_acl_path($self, $user, $path);
   $roles = $acl->{roles}->{$path} || [];
   return @$roles;
}

sub permissions {
    my ($self, $user, $path) = @_;

    if ($user eq 'root@pam') { # root can do anything
	my $cfg = $self->{user_cfg};
	return $cfg->{roles}->{'Administrator'};
    } 

    $user = PVE::AccessControl::verify_username($user, 1);
    return {} if !$user;

    my $cache = $self->{aclcache};
    $cache->{$user} = {} if !$cache->{$user};

    my $acl = $cache->{$user};

    my $perm = $acl->{privs}->{$path};
    return $perm if $perm;

    return &$compile_acl_path($self, $user, $path);
}

sub check {
    my ($self, $user, $path, $privs, $noerr) = @_;

    my $perm = $self->permissions($user, $path);

    foreach my $priv (@$privs) {
	PVE::AccessControl::verify_privname($priv);
	if (!$perm->{$priv}) {
	    return undef if $noerr;
	    raise_perm_exc("$path, $priv"); 
	}
    };

    return 1;
};

sub check_any {
    my ($self, $user, $path, $privs, $noerr) = @_;

    my $perm = $self->permissions($user, $path);

    my $found = 0;
    foreach my $priv (@$privs) {
	PVE::AccessControl::verify_privname($priv);
	if ($perm->{$priv}) {
	    $found = 1;
	    last;
	}
    };

    return 1 if $found;

    return undef if $noerr;

    raise_perm_exc("$path, " . join("|", @$privs)); 
};

sub check_user_enabled {
    my ($self, $user, $noerr) = @_;
    
    my $cfg = $self->{user_cfg};
    return PVE::AccessControl::check_user_enabled($cfg, $user, $noerr);
}

sub check_user_exist {
    my ($self, $user, $noerr) = @_;
    
    my $cfg = $self->{user_cfg};
    return PVE::AccessControl::check_user_exist($cfg, $user, $noerr);
}

sub is_group_member {
    my ($self, $group, $user) = @_;

    my $cfg = $self->{user_cfg};

    return 0 if !$cfg->{groups}->{$group};

    return defined($cfg->{groups}->{$group}->{users}->{$user});
}

sub filter_groups {
    my ($self, $user, $privs, $any) = @_;

    my $cfg = $self->{user_cfg};

    my $groups = {};
    foreach my $group (keys %{$cfg->{groups}}) {
	my $path = "/access/groups/$group";
	if ($any) {
	    if ($self->check_any($user, $path, $privs, 1)) {
		$groups->{$group} = $cfg->{groups}->{$group};
	    }
	} else {
	    if ($self->check($user, $path, $privs, 1)) {
		$groups->{$group} = $cfg->{groups}->{$group};
	    }
	}
    }

    return $groups;
}

sub group_member_join {
    my ($self, $grouplist) = @_;

    my $users = {};

    my $cfg = $self->{user_cfg};
    foreach my $group (@$grouplist) {
	my $data = $cfg->{groups}->{$group};
	next if !$data;
	foreach my $user (keys %{$data->{users}}) {
	    $users->{$user} = 1;
	}
    }

    return $users;
}

sub exec_api2_perm_check {
    my ($self, $check, $username, $param, $noerr) = @_;

    # syslog("info", "CHECK " . join(', ', @$check));

    my $ind = 0;
    my $test = $check->[$ind++];
    die "no permission test specified" if !$test;
 
    if ($test eq 'and') {
	while (my $subcheck = $check->[$ind++]) {
	    $self->exec_api2_perm_check($subcheck, $username, $param); 
	}
	return 1;
    } elsif ($test eq 'or') {
	while (my $subcheck = $check->[$ind++]) {
	    return 1 if $self->exec_api2_perm_check($subcheck, $username, $param, 1); 
	}
	return 0 if $noerr;
	raise_perm_exc();
    } elsif ($test eq 'perm') {
	my ($t, $tmplpath, $privs, %options) = @$check;
	my $any = $options{any};
	die "missing parameters" if !($tmplpath && $privs);
	my $path = PVE::Tools::template_replace($tmplpath, $param);
	if ($any) {
	    return $self->check_any($username, $path, $privs, $noerr);
	} else {
	    return $self->check($username, $path, $privs, $noerr);
	}
    } elsif ($test eq 'userid-group') {
	my $userid = $param->{userid};
	my ($t, $privs, %options) = @$check;
	return if !$options{groups_param} && !$self->check_user_exist($userid, $noerr);
	if (!$self->check_any($username, "/access", $privs, 1)) {
	    my $groups = $self->filter_groups($username, $privs, 1);
	    if ($options{groups_param}) {
		my @group_param = PVE::Tools::split_list($param->{groups});
		raise_perm_exc("/access, " . join("|", @$privs)) if !scalar(@group_param);
		foreach my $pg (@group_param) {
		    raise_perm_exc("/access/groups/$pg, " . join("|", @$privs))
			if !$groups->{$pg};
		}
	    } else {
		my $allowed_users = $self->group_member_join([keys %$groups]);
		if (!$allowed_users->{$userid}) {
		    return 0 if $noerr;
		    raise_perm_exc();
		}
	    }
	}
	return 1;
    } elsif ($test eq 'userid-param') {
	my $userid = $param->{userid};
	return if !$self->check_user_exist($userid, $noerr);
	my ($t, $subtest) = @$check;
	die "missing parameters" if !$subtest;
	if ($subtest eq 'self') {
	    return 1 if $username eq 'userid';
	    return 0 if $noerr;
	    raise_perm_exc();
	} else {
	    die "unknown userid-param test";
	}
    } else {
	die "unknown permission test";
    }
};

sub check_api2_permissions {
    my ($self, $perm, $username, $param) = @_;

    return 1 if !$username && $perm->{user} eq 'world';

    raise_perm_exc("user != null") if !$username;

    return 1 if $username eq 'root@pam';

    raise_perm_exc('user != root@pam') if !$perm;

    return 1 if $perm->{user} && $perm->{user} eq 'all';

    return $self->exec_api2_perm_check($perm->{check}, $username, $param) 
	if $perm->{check};

    raise_perm_exc();
}

# initialize environment - must be called once at program startup
sub init {
    my ($class, $type, %params) = @_;

    $class = ref($class) || $class;

    die "already initialized" if $pve_env;

    die "unknown environment type" if !$type || $type !~ m/^(cli|pub|priv|ha)$/;

    $SIG{CHLD} = $worker_reaper;

    # environment types
    # cli  ... command started fron command line
    # pub  ... access from public server (apache)
    # priv ... access from private server (pvedaemon)
    # ha   ... access from HA resource manager agent (rgmanager)
    
    my $self = {
	user_cfg => {},
	aclcache => {},
	aclversion => undef,
	type => $type,
    };

    bless $self, $class;

    foreach my $p (keys %params) {
	if ($p eq 'atfork') {
	    $self->{$p} = $params{$p};
	} else {
	    die "unknown option '$p'";
	}
    }

    $pve_env = $self;

    my ($sysname, $nodename) = POSIX::uname();

    $nodename =~ s/\..*$//; # strip domain part, if any

    $self->{nodename} = $nodename;

    return $self;
}; 

# get the singleton 
sub get {

    die "not initialized" if !$pve_env;

    return $pve_env;
}

sub parse_params {
    my ($self, $enable_upload) = @_;

    if ($self->{request_rec}) {
	my $cgi;
	if ($enable_upload) {
	    $cgi = CGI->new($self->{request_rec});
	} else {
	    # disable upload using empty upload_hook
	    $cgi = CGI->new($self->{request_rec}, sub {}, undef, 0);
	}
	$self->{cgi} = $cgi;
	my $params = $cgi->Vars();
	return PVE::Tools::decode_utf8_parameters($params);
    } elsif ($self->{params}) {
	return $self->{params};
    } else {
	die "no parameters registered";
    }
}

sub get_upload_info {
    my ($self, $param) = @_;

    my $cgi = $self->{cgi};
    die "CGI not initialized" if !$cgi;

    my $pd = $cgi->param($param);
    die "unable to get cgi parameter info\n" if !$pd;
    my $info = $cgi->uploadInfo($pd);
    die "unable to get cgi upload info\n" if !$info;

    my $res = { %$info };

    my $tmpfilename = $cgi->tmpFileName($pd);
    die "unable to get cgi upload file name\n" if !$tmpfilename;
    $res->{tmpfilename} = $tmpfilename;

    #my $hndl = $cgi->upload($param);
    #die "unable to get cgi upload handle\n" if !$hndl;
    #$res->{handle} = $hndl->handle;

    return $res;
}

# init_request - must be called before each RPC request
sub init_request {
    my ($self, %params) = @_;

    PVE::Cluster::cfs_update();

    $self->{result_attributes} = {};

    my $userconfig; # we use this for regression tests
    foreach my $p (keys %params) {
	if ($p eq 'userconfig') {
	    $userconfig = $params{$p};
	} elsif ($p eq 'request_rec') {
	    # pass Apache2::RequestRec
	    $self->{request_rec} = $params{$p};
	} elsif ($p eq 'params') {
	    $self->{params} = $params{$p};
	} else {
	    die "unknown parameter '$p'";
	}
    }

    eval {
	$self->{aclcache} = {};
	if ($userconfig) {
	    my $ucdata = PVE::Tools::file_get_contents($userconfig);
	    my $cfg = PVE::AccessControl::parse_user_config($userconfig, $ucdata);
	    $self->{user_cfg} = $cfg;
	    #print Dumper($cfg);
	} else {
	    my $ucvers = PVE::Cluster::cfs_file_version('user.cfg'); 
	    if (!$self->{aclcache} || !defined($self->{aclversion}) || 
		!defined($ucvers) ||  ($ucvers ne $self->{aclversion})) {
		$self->{aclversion} = $ucvers;
		my $cfg = PVE::Cluster::cfs_read_file('user.cfg');
		$self->{user_cfg} = $cfg;
	    }
	}
    };
    if (my $err = $@) {
	$self->{user_cfg} = {};
	die "Unable to load access control list: $err";
    }
}

sub set_client_ip {
    my ($self, $ip) = @_;

    $self->{client_ip} = $ip;
}

sub get_client_ip {
    my ($self) = @_;

    return $self->{client_ip};
}

sub set_result_attrib {
    my ($self, $key, $value) = @_;

    $self->{result_attributes}->{$key} = $value;
}

sub get_result_attrib {
    my ($self, $key) = @_;

    return $self->{result_attributes}->{$key};
}

sub set_language {
    my ($self, $lang) = @_;

    # fixme: initialize I18N

    $self->{language} = $lang;
}

sub get_language {
    my ($self) = @_;

    return $self->{language};
}

sub set_user {
    my ($self, $user) = @_;

    # fixme: get ACLs

    $self->{user} = $user;
}

sub get_user {
    my ($self) = @_;

    die "user name not set\n" if !$self->{user};

    return $self->{user};
}

# read/update list of active workers 
# we move all finished tasks to the archive index,
# but keep aktive and most recent task in the active file.
# $nocheck ... consider $new_upid still running (avoid that
# we try to read the reult to early.
sub active_workers  {
    my ($new_upid, $nocheck) = @_;

    my $lkfn = "/var/log/pve/tasks/.active.lock";

    my $timeout = 10;

    my $code = sub {

	my $tasklist = PVE::INotify::read_file('active');

	my @ta;
	my $tlist = [];
	my $thash = {}; # only list task once

	my $check_task = sub {
	    my ($task, $running) = @_;

	    if ($running || PVE::ProcFSTools::check_process_running($task->{pid}, $task->{pstart})) {
		push @$tlist, $task;
	    } else {
		delete $task->{pid};
		push @ta, $task;
	    }
	    delete $task->{pstart};
	};

	foreach my $task (@$tasklist) {
	    my $upid = $task->{upid};
	    next if $thash->{$upid};
	    $thash->{$upid} = $task;
	    &$check_task($task);
	}

	if ($new_upid && !(my $task = $thash->{$new_upid})) {
	    $task = PVE::Tools::upid_decode($new_upid);
	    $task->{upid} = $new_upid;
	    $thash->{$new_upid} = $task;
	    &$check_task($task, $nocheck);
	}


	@ta = sort { $b->{starttime} cmp $a->{starttime} } @ta;

	my $save = defined($new_upid);

	foreach my $task (@ta) {
	    next if $task->{endtime};
	    $task->{endtime} = time();
	    $task->{status} = PVE::Tools::upid_read_status($task->{upid});
	    $save = 1;
	}

	my $archive = '';
	my @arlist = ();
	foreach my $task (@ta) {
	    if (!$task->{saved}) {
		$archive .= sprintf("$task->{upid} %08X $task->{status}\n", $task->{endtime});
		$save = 1;
		push @arlist, $task;
		$task->{saved} = 1;
	    }
	}

	if ($archive) {
	    my $size = 0;
	    my $filename = "/var/log/pve/tasks/index";
	    eval {
		my $fh = IO::File->new($filename, '>>', 0644) ||
		    die "unable to open file '$filename' - $!\n";
		PVE::Tools::safe_print($filename, $fh, $archive);
		$size = -s $fh;
		close($fh) ||
		    die "unable to close file '$filename' - $!\n";
	    };
	    my $err = $@;
	    if ($err) {
		syslog('err', $err);
		foreach my $task (@arlist) { # mark as not saved
		    $task->{saved} = 0;
		}
	    }
	    my $maxsize = 50000; # about 1000 entries
	    if ($size > $maxsize) {
		rename($filename, "$filename.1");
	    }
	}

	# we try to reduce the amount of data
	# list all running tasks and task and a few others
	# try to limit to 25 tasks
	my $ctime = time();
	my $max = 25 - scalar(@$tlist);
        foreach my $task (@ta) {
	    last if $max <= 0;
	    push @$tlist, $task;
	    $max--;
	}

	PVE::INotify::write_file('active', $tlist) if $save;

	return $tlist;
    };

    my $res = PVE::Tools::lock_file($lkfn, $timeout, $code);
    die $@ if $@;

    return $res;
}

my $kill_process_group = sub {
    my ($pid, $pstart) = @_;

    # send kill to process group (negative pid)
    my $kpid = -$pid;

    # always send signal to all pgrp members
    kill(15, $kpid); # send TERM signal

    # give max 5 seconds to shut down
    for (my $i = 0; $i < 5; $i++) {
	return if !PVE::ProcFSTools::check_process_running($pid, $pstart);
	sleep (1);
    }
       
    # to be sure
    kill(9, $kpid); 
};

sub check_worker {
    my ($upid, $killit) = @_;

    my $task = PVE::Tools::upid_decode($upid);

    my $running = PVE::ProcFSTools::check_process_running($task->{pid}, $task->{pstart});

    return 0 if !$running;

    if ($killit) {
	&$kill_process_group($task->{pid});
	return 0;
    }

    return 1;
}

# start long running workers
# STDIN is redirected to /dev/null
# STDOUT,STDERR are redirected to the filename returned by upid_decode
# NOTE: we simulate running in foreground if ($self->{type} eq 'cli')
sub fork_worker {
    my ($self, $dtype, $id, $user, $function) = @_;

    $dtype = 'unknown' if !defined ($dtype);
    $id = '' if !defined ($id);

    $user = 'root@pve' if !defined ($user);

    my $sync = $self->{type} eq 'cli' ? 1 : 0;

    local $SIG{INT} = 
	local $SIG{QUIT} = 
	local $SIG{PIPE} = 
	local $SIG{TERM} = 'IGNORE';

    my $starttime = time ();

    my @psync = POSIX::pipe();
    my @csync = POSIX::pipe();

    my $node = $self->{nodename};

    my $cpid = fork();
    die "unable to fork worker - $!" if !defined($cpid);

    my $workerpuid = $cpid ? $cpid : $$;

    my $pstart = PVE::ProcFSTools::read_proc_starttime($workerpuid) ||
	die "unable to read process start time";

    my $upid = PVE::Tools::upid_encode ({
	node => $node, pid => $workerpuid, pstart => $pstart, 
	starttime => $starttime, type => $dtype, id => $id, user => $user });

    my $outfh;

    if (!$cpid) { # child

	$0 = "task $upid";

	$SIG{INT} = $SIG{QUIT} = $SIG{TERM} = sub { die "received interrupt\n"; };

	$SIG{CHLD} = $SIG{PIPE} = 'DEFAULT';

	# set sess/process group - we want to be able to kill the
	# whole process group
	POSIX::setsid(); 

	POSIX::close ($psync[0]);
	POSIX::close ($csync[1]);

	$outfh = $sync ? $psync[1] : undef;

	eval {
	    PVE::INotify::inotify_close();

	    if (my $atfork = $self->{atfork}) {
		&$atfork();
	    }

	    # same algorythm as used inside SA
	    # STDIN = /dev/null
	    my $fd = fileno (STDIN);

	    if (!$sync) {
		close STDIN;
		POSIX::close(0) if $fd != 0;

		die "unable to redirect STDIN - $!" 
		    if !open(STDIN, "</dev/null");

		$outfh = PVE::Tools::upid_open($upid);
	    }


	    # redirect STDOUT
	    $fd = fileno(STDOUT);
	    close STDOUT;
	    POSIX::close (1) if $fd != 1;

	    die "unable to redirect STDOUT - $!" 
		if !open(STDOUT, ">&", $outfh);

	    STDOUT->autoflush (1);
      
	    #  redirect STDERR to STDOUT
	    $fd = fileno (STDERR);
	    close STDERR;
	    POSIX::close(2) if $fd != 2;

	    die "unable to redirect STDERR - $!" 
		if !open(STDERR, ">&1");
	    
	    STDERR->autoflush(1);
	};
	if (my $err = $@) {
	    my $msg =  "ERROR: $err";
	    POSIX::write($psync[1], $msg, length ($msg));
	    POSIX::close($psync[1]);
	    POSIX::_exit(1); 
	    kill(-9, $$); 
	}

	# sync with parent (signal that we are ready)
	if ($sync) {
	    print "$upid\n";
	} else {
	    POSIX::write($psync[1], $upid, length ($upid));
	    POSIX::close($psync[1]);
	}

	my $readbuf = '';
	# sync with parent (wait until parent is ready)
	POSIX::read($csync[0], $readbuf, 4096);
	die "parent setup error\n" if $readbuf ne 'OK';

	if ($self->{type} eq 'ha') {
	    print "task started by HA resource agent\n";
	}
	eval { &$function($upid); };
	my $err = $@;
	if ($err) {
	    chomp $err;
	    $err =~ s/\n/ /mg;
	    syslog('err', $err);
	    print STDERR "TASK ERROR: $err\n";
	    POSIX::_exit(-1); 
	} else {
	    print STDERR "TASK OK\n";
	    POSIX::_exit(0);
	} 
	kill(-9, $$); 
    }

    # parent

    POSIX::close ($psync[1]);
    POSIX::close ($csync[0]);

    my $readbuf = '';
    # sync with child (wait until child starts)
    POSIX::read($psync[0], $readbuf, 4096);

    if (!$sync) {
	POSIX::close($psync[0]);
	&$register_worker($cpid, $user, $upid);
    } else {
	chomp $readbuf;
    }

    eval {
	die "got no worker upid - start worker failed\n" if !$readbuf;

	if ($readbuf =~ m/^ERROR:\s*(.+)$/m) {
	    die "starting worker failed: $1\n";
	}

	if ($readbuf ne $upid) {
	    die "got strange worker upid ('$readbuf' != '$upid') - start worker failed\n";
	}

	if ($sync) {
	    $outfh = PVE::Tools::upid_open($upid);
	}
    };
    my $err = $@;

    if (!$err) {
	my $msg = 'OK';
	POSIX::write($csync[1], $msg, length ($msg));
	POSIX::close($csync[1]);
       
    } else {
	POSIX::close($csync[1]);
	kill(-9, $cpid); # make sure it gets killed
	die $err;
    }

    PVE::Cluster::log_msg('info', $user, "starting task $upid");

    my $tlist = active_workers($upid, $sync);
    PVE::Cluster::broadcast_tasklist($tlist);
   
    my $res = 0;

    if ($sync) {
	my $count;
	my $outbuf = '';
	my $int_count = 0;
	eval {
	    local $SIG{INT} = local $SIG{QUIT} = local $SIG{TERM} = sub { 
		# always send signal to all pgrp members
		my $kpid = -$cpid;
		if ($int_count < 3) {
		    kill(15, $kpid); # send TERM signal
		} else {
		    kill(9, $kpid); # send KILL signal
		}
		$int_count++;
	    };
	    local $SIG{PIPE} = sub { die "broken pipe\n"; };

	    my $select = new IO::Select;    
	    my $fh = IO::Handle->new_from_fd($psync[0], 'r');
	    $select->add($fh);

	    while ($select->count) {
		my @handles = $select->can_read(1);
		if (scalar(@handles)) {
		    my $count = sysread ($handles[0], $readbuf, 4096);
		    if (!defined ($count)) {
			my $err = $!;
			die "sync pipe read error: $err\n";
		    }
		    last if $count == 0; # eof

		    $outbuf .= $readbuf;
		    while ($outbuf =~ s/^(([^\010\r\n]*)(\r|\n|(\010)+|\r\n))//s) {
			my $line = $1;
			my $data = $2;
			if ($data =~ m/^TASK OK$/) {
			    # skip
			} elsif ($data =~ m/^TASK ERROR: (.+)$/) {
			    print STDERR "$1\n";
			} else {
			    print $line;
			}
			if ($outfh) {
			    print $outfh $line;
			    $outfh->flush();
			}
		    }
		} else {
		    # some commands daemonize without closing stdout
		    last if !PVE::ProcFSTools::check_process_running($cpid);
		}
	    }
	};
	my $err = $@;

	POSIX::close($psync[0]);

	if ($outbuf) { # just to be sure
	    print $outbuf;
	    if ($outfh) {
		print $outfh $outbuf;
	    }
	}

	if ($err) {
	    $err =~ s/\n/ /mg;
	    print STDERR "$err\n";
	    if ($outfh) {
		print $outfh "TASK ERROR: $err\n";
	    }
	}

	&$kill_process_group($cpid, $pstart); # make sure it gets killed

	close($outfh);

	waitpid($cpid, 0);
	$res = $?;
	&$log_task_result($upid, $user, $res);
    }

    return wantarray ? ($upid, $res) : $upid;
}

1;