implement agent exec api call

this imitates the qemu-guest-agent interface
with an 'exec' api call which returns a pid
and an 'exec-status' api call which takes a pid

the command for the exec call is given as an 'alist'
which means that when using we have to give the 'command'
parameter multiple times e.g.

pvesh create <...>/exec --command ls --command '-lha' --command '/home/user'

so that we avoid having to deal with shell escaping etc.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

PVE/API2/Qemu/Agent.pm

@@ -112,6 +112,8 @@ __PACKAGE__->register_method({
 
 	my $cmds = [keys %$guest_agent_commands];
 	push @$cmds, qw(
+	    exec
+	    exec-status
 	    set-user-password
 	);
 
@@ -250,4 +252,114 @@ __PACKAGE__->register_method({
 	return { result => $res };
     }});
 
+__PACKAGE__->register_method({
+    name => 'exec',
+    path => 'exec',
+    method => 'POST',
+    protected => 1,
+    proxyto => 'node',
+    description => "Executes the given command in the vm via the guest-agent and returns an object with the pid.",
+    permissions => { check => [ 'perm', '/vms/{vmid}', [ 'VM.Monitor' ]]},
+    parameters => {
+	additionalProperties => 0,
+	properties => {
+	    node => get_standard_option('pve-node'),
+	    vmid => get_standard_option('pve-vmid', {
+		    completion => \&PVE::QemuServer::complete_vmid_running }),
+	    command => {
+		type => 'string',
+		format => 'string-alist',
+		description => 'The command as a list of program + arguments',
+	    }
+	},
+    },
+    returns => {
+	type => 'object',
+	properties => {
+	    pid => {
+		type => 'integer',
+		description => "The PID of the process started by the guest-agent.",
+	    },
+	},
+    },
+    code => sub {
+	my ($param) = @_;
+
+	my $vmid = $param->{vmid};
+	my $cmd = [PVE::Tools::split_list($param->{command})];
+
+	my $res = PVE::QemuServer::Agent::qemu_exec($vmid, $cmd);
+	return $res;
+    }});
+
+__PACKAGE__->register_method({
+    name => 'exec-status',
+    path => 'exec-status',
+    method => 'GET',
+    protected => 1,
+    proxyto => 'node',
+    description => "Gets the status of the given pid started by the guest-agent",
+    permissions => { check => [ 'perm', '/vms/{vmid}', [ 'VM.Monitor' ]]},
+    parameters => {
+	additionalProperties => 0,
+	properties => {
+	    node => get_standard_option('pve-node'),
+	    vmid => get_standard_option('pve-vmid', {
+		    completion => \&PVE::QemuServer::complete_vmid_running }),
+	    pid => {
+		type => 'integer',
+		description => 'The PID to query'
+	    },
+	},
+    },
+    returns => {
+	type => 'object',
+	properties => {
+	    exited => {
+		type => 'boolean',
+		description => 'Tells if the given command has exited yet.',
+	    },
+	    exitcode => {
+		type => 'integer',
+		optional => 1,
+		description => 'process exit code if it was normally terminated.',
+	    },
+	    signal=> {
+		type => 'integer',
+		optional => 1,
+		description => 'signal number or exception code if the process was abnormally terminated.',
+	    },
+	    'out-data' => {
+		type => 'string',
+		optional => 1,
+		description => 'stdout of the process',
+	    },
+	    'err-data' => {
+		type => 'string',
+		optional => 1,
+		description => 'stderr of the process',
+	    },
+	    'out-truncated' => {
+		type => 'boolean',
+		optional => 1,
+		description => 'true if stdout was not fully captured',
+	    },
+	    'err-truncated' => {
+		type => 'boolean',
+		optional => 1,
+		description => 'true if stderr was not fully captured',
+	    },
+	},
+    },
+    code => sub {
+	my ($param) = @_;
+
+	my $vmid = $param->{vmid};
+	my $pid = int($param->{pid});
+
+	my $res = PVE::QemuServer::Agent::qemu_exec_status($vmid, $pid);
+
+	return $res;
+    }});
+
 1;

PVE/QemuServer/Agent.pm

@@ -3,6 +3,8 @@ package PVE::QemuServer::Agent;
 use strict;
 use warnings;
 use PVE::QemuServer;
+use MIME::Base64 qw(decode_base64);
+use JSON;
 use base 'Exporter';
 
 our @EXPORT_OK = qw(
@@ -62,4 +64,52 @@ sub agent_cmd {
     return $res;
 }
 
+sub qemu_exec {
+    my ($vmid, $cmd) = @_;
+
+
+    my $path = shift @$cmd;
+    my $arguments = $cmd;
+
+    my $args = {
+	path => $path,
+	arg => $arguments,
+	'capture-output' => JSON::true,
+    };
+    my $res = agent_cmd($vmid, "exec", $args, "can't execute command '$path $arguments'");
+
+    return $res;
+}
+
+sub qemu_exec_status {
+    my ($vmid, $pid) = @_;
+
+    my $res = agent_cmd($vmid, "exec-status", { pid => $pid }, "can't get exec status for '$pid'");
+
+    if ($res->{'out-data'}) {
+	my $decoded = eval { decode_base64($res->{'out-data'}) };
+	warn $@ if $@;
+	if (defined($decoded)) {
+	    $res->{'out-data'} = $decoded;
+	}
+    }
+
+    if ($res->{'err-data'}) {
+	my $decoded = eval { decode_base64($res->{'err-data'}) };
+	warn $@ if $@;
+	if (defined($decoded)) {
+	    $res->{'err-data'} = $decoded;
+	}
+    }
+
+    # convert JSON::Boolean to 1/0
+    foreach my $d (keys %$res) {
+	if (JSON::is_bool($res->{$d})) {
+	    $res->{$d} = ($res->{$d})? 1 : 0;
+	}
+    }
+
+    return $res;
+}
+
 1;