admin-tools/dmaster-signal

   1 #!/usr/bin/env perl
   2
   3 use Pod::Usage;
   4 use Socket;
   5 use Config;
   6 @signal_names = split ' ', $Config{'sig_name'};
   7 @signal_numbers{@signal_names} = split ' ', $Config{'sig_num'};
   8 require "syscall.ph";
   9
  10 $0 = 'dmaster-signal';
  11 $daemon_id = shift @ARGV;
  12 $signal = shift @ARGV;
  13
  14 unless($daemon_id and defined $signal)
  15 {
  16         pod2usage(-exitval=>2, -verbose=>99);
  17 }
  18
  19 $signal_num = $signal_numbers{$signal} // $signal;
  20 die "$0: unknown signal: $signal\n" unless $signal_num =~ /^\d+$/;
  21
  22
  23 $management_socket_path = ($ENV{'XDG_CACHE_HOME'} || '/var/run').'/dmaster.sock';
  24 $management_socket_addr = sockaddr_un($management_socket_path);
  25 socket($management_socket, AF_UNIX, SOCK_STREAM, 0) or die "socket: $!\n";
  26 connect($management_socket, $management_socket_addr) or die "connect: $management_socket_path: $!\n";
  27
  28 while(<$management_socket>)
  29 {
  30         chomp;
  31         last if /^END$/;
  32         if(/^dmaster\.pid\s+(\d+)$/)
  33         {
  34                 $dmaster_pid = $1;
  35         }
  36         elsif(/^daemon\.(.+)\.pidfd\.fileno\s+(\d+)$/ and $1 eq $daemon_id)
  37         {
  38                 $target_pidfd = $2;
  39         }
  40 }
  41
  42 if(not $dmaster_pid)
  43 {
  44         die "$0: could not find dmaster pid\n";
  45 }
  46 if(not $target_pidfd)
  47 {
  48         die "$0: could not find daemon's pidfd: $daemon_id\n";
  49 }
  50
  51
  52 $flags = 0;
  53 $! = 0;
  54 $dmaster_pidfd = syscall SYS_pidfd_open(), int $dmaster_pid, $flags;
  55 if($dmaster_pidfd == -1)
  56 {
  57         die "pidfd_open: $!\n";
  58 }
  59
  60
  61 $flags = 0;
  62 $! = 0;
  63 $pidfd = syscall SYS_pidfd_getfd(), int $dmaster_pidfd, int $target_pidfd, $flags;
  64 if($pidfd == -1)
  65 {
  66         die "pidfd_getfd: $!\n";
  67 }
  68
  69
  70 print {$management_socket} "\n";
  71 close $management_socket;
  72
  73
  74 $flags = 0;
  75 $! = 0;
  76 $ret = syscall SYS_pidfd_send_signal(), int $pidfd, int $signal_num, undef, $flags;
  77 if($ret == -1)
  78 {
  79         die "pidfd_send_signal: $!\n";
  80 }
  81
  82 exit 0;
  83
  84
  85
  86 __END__
  87
  88 =pod
  89
  90 =head1 NAME
  91
  92 dmaster-signal - Send a signal to a daemon managed by dmaster
  93
  94 =head1 SYNOPSIS
  95
  96 dmaster-signal I<DAEMON-ID> I<SIGNAL>
  97
  98 =head1 DESCRIPTION
  99
 100 dmaster-signal(1) utilizes PIDFD to reliably send signal to the daemon
 101 managed by dmaster(1) and specified by I<DAEMON-ID>.
 102
 103 I<SIGNAL> is either numeric or symbolic signal name.
 104
 105 =head1 SEE ALSO
 106
 107 dmaster(1), pidfd_send_signal(2), signal(7)
 108
 109 =cut