[pve-devel] [PATCH qemu-server] fix #1934: add qemu fw_cfg variables via 'tags'

[Dominik Csapak]

this add the 'tags' property to vms, which has the format:

key=value(;key=value)*

each value will be set as

-fw_cfg 'name=opt/com.proxmox/$key,string=$value'
(qemu recommends using a unique rfqdn)

this way, users can tag the vm with that information available inside
e.g. under linux the value can be read under

/sys/firmware/qemu_fw_cfg/by_name/opt/com.proxmox./$key/raw

see the file docs/specs/fw_cfg.txt in the qemu repository for more
details

maybe we can also use this in the future to show/set in the gui
e.g. some grouping/ordering etc.

Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
 PVE/QemuServer.pm | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 9f5bf56..d55a1ae 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -232,6 +232,29 @@ my $watchdog_fmt = {
 };
 PVE::JSONSchema::register_format('pve-qm-watchdog', $watchdog_fmt);
 
+PVE::JSONSchema::register_format('pve-qm-tags', \&verify_tag_format);
+sub verify_tag_format {
+    my ($tagstring, $noerr) = @_;
+
+    if (!$tagstring) {
+	return '';
+    }
+
+    # forbid all characters not in range 0x20-0x7E
+    for my $tag (split(';', $tagstring)) {
+	my ($key, $value) = ($tag =~ m/^(.*)=(.*)$/);
+	if ($key =~ m/[\x00-\x1F\x7F-\xFF]/) {
+	    die "invalid character in tag key\n" if !$noerr;
+	    return undef;
+	}
+	if ($value =~ m/[\x00-\x1F\x7F-\xFF]/) {
+	    die "invalid character in tag value\n" if !$noerr;
+	    return undef;
+	}
+    }
+
+    return $tagstring;
+}
 my $agent_fmt = {
     enabled => {
 	description => "Enable/disable Qemu GuestAgent.",
@@ -672,6 +695,13 @@ EODESCR
 	description => "Configure a audio device, useful in combination with QXL/Spice.",
 	optional => 1
     },
+    tags => {
+	description => "Specify key/value pairs to be added to qemu fw_cfg.",
+	type => 'string',
+	maxLength => 4096,
+	format => 'pve-qm-tags',
+	optional => 1,
+    },
 };
 
 my $cicustom_fmt = {
@@ -4152,6 +4182,13 @@ sub config_to_command {
 	push @$cmd, '-loadstate', $statepath;
     }
 
+    if ($conf->{tags}) {
+	for my $tag (split(';', $conf->{tags})) {
+	    my ($key, $value) = ($tag =~ m/^(.*)=(.*)$/);
+	    push @$cmd, '-fw_cfg', "name=opt/com.proxmox/$key,string=$value";
+	}
+    }
+
     # add custom args
     if ($conf->{args}) {
 	my $aa = PVE::Tools::split_args($conf->{args});
-- 
2.20.1