Add a pure Perl reimplementation of systemd's sd_notify() mechanism as defined in systemd/sd-daemon.h based on the example implementations in 'man 3 sd_notify'.
The initial user of this helper is intended to be the pve-dbus-vmstate service, so it can notify startup completion only once the dbus-vmstate QEMU object is ready to be used. EAGAIN is not checked for, because it does not occur for blocking Unix domain sockets, see 'man 2 send'. The socket is a datagram socket and a single datagram will be sent. If not all data can be written, error out like the example code in 'man 3 sd_notify'. Co-developed-by: Thomas Lamprecht <[email protected]> Co-developed-by: Wolfgang Bumiller <[email protected]> Signed-off-by: Fiona Ebner <[email protected]> --- Changes in v4: * Also handle abstract socket path. * Only resend upon EINTR, otherwise the datagram should be sent in one go. * Drop unnecessary flush. * Drop $unset_environment argument. * Rename to just PVE::Systemd::notify() to make it clear that it's not the exact same as sd_notify(). * Use POD for documentation. * Return early if there is no socket path. * Die if there is no message. * Check that socket path starts with '/' or '@'. src/PVE/Systemd.pm | 49 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) diff --git a/src/PVE/Systemd.pm b/src/PVE/Systemd.pm index e6d6f88..8fc06a5 100644 --- a/src/PVE/Systemd.pm +++ b/src/PVE/Systemd.pm @@ -3,9 +3,12 @@ package PVE::Systemd; use strict; use warnings; +use IO::Socket::UNIX; use Net::DBus qw(dbus_uint32 dbus_uint64 dbus_boolean); use Net::DBus::Callback; use Net::DBus::Reactor; +use POSIX qw(EINTR); +use Socket qw(SOCK_DGRAM); use PVE::Tools qw(file_set_contents file_get_contents trim); @@ -282,4 +285,50 @@ sub write_ini { file_set_contents($filename, $content); } +=head3 notify() + +This is a pure Perl reimplementation of systemd's C<sd_notify()> mechanism as defined in +C<systemd/sd-daemon.h>, based on the example implementations in C<man 3 sd_notify>. Does not return +a value, but dies upon error. + +=cut + +sub notify { + my ($message) = @_; + + # nothing to do if there is no socket + my $socket_path = $ENV{NOTIFY_SOCKET} or return; + + die "notify systemd invalid socket path '$socket_path'\n" if $socket_path !~ m|^[/@]|; + die "notify systemd called without a message\n" if !$message; + + # might be an abstract socket + $socket_path =~ s/^@/\0/; + + my $socket = IO::Socket::UNIX->new( + Type => SOCK_DGRAM(), + Peer => $socket_path, + ) or die "notify systemd: unable to connect to socket $socket_path - $IO::Socket::errstr\n"; + + # we won't be reading from the socket + $socket->shutdown(SHUT_RD); + + my $res; + while (1) { + $res = $socket->send($message); + if ($res) { + die "notify systemd: protocol error writing to socket '$socket_path'\n" + if $res < length($message); + last; + } else { + next if $! == EINTR; + die "notify systemd: sending to '$socket_path' failed - $!\n"; + } + } + + close($socket); + + return; +} + 1; -- 2.47.3 _______________________________________________ pve-devel mailing list [email protected] https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel
