Add run_fork_with_timeout utility

[pve-common.git] / src / PVE / Tools.pm

diff --git a/src/PVE/Tools.pm b/src/PVE/Tools.pm
index 30322b2888246a8b6ae1c139f370582de936db7e..bd025e21fed29d17d730ba0bd4f1773e07abad4a 100644 (file)
--- a/src/PVE/Tools.pm
+++ b/src/PVE/Tools.pm
@@ -4,7 +4,8 @@ use strict;
 use warnings;
 use POSIX qw(EINTR EEXIST EOPNOTSUPP);
 use IO::Socket::IP;
-use Socket qw(AF_INET AF_INET6 AI_ALL AI_V4MAPPED AI_CANONNAME SOCK_DGRAM);
+use Socket qw(AF_INET AF_INET6 AI_ALL AI_V4MAPPED AI_CANONNAME SOCK_DGRAM
+             IPPROTO_TCP);
 use IO::Select;
 use File::Basename;
 use File::Path qw(make_path);
@@ -738,18 +739,16 @@ sub wait_for_vnc_port {
     my $starttime = [gettimeofday];
     my $elapsed;
 
+    my $found;
     while (($elapsed = tv_interval($starttime)) < $timeout) {
-       if (my $fh = IO::File->new ("/proc/net/tcp", "r")) {
-           while (defined (my $line = <$fh>)) {
-               if ($line =~ m/^\s*\d+:\s+([0-9A-Fa-f]{8}):([0-9A-Fa-f]{4})\s/) {
-                   if ($port == hex($2)) {
-                       close($fh);
-                       return 1;
-                   }
-               }
+       # -Htln = don't print header, tcp, listening sockets only, numeric ports
+       run_command(['/bin/ss', '-Htln', "sport = :$port"], outfunc => sub {
+           my $line = shift;
+           if ($line =~ m/^LISTEN\s+\d+\s+\d+\s+\S+:(\d+)\s/) {
+               $found = 1 if ($port == $1);
            }
-           close($fh);
-       }
+       });
+       return 1 if $found;
        $sleeptime += 100000 if  $sleeptime < 1000000;
        usleep($sleeptime);
     }
@@ -789,7 +788,7 @@ sub next_unused_port {
        my %sockargs = (Listen => 5,
                        ReuseAddr => 1,
                        Family    => $family,
-                       Proto     => 0,
+                       Proto     => IPPROTO_TCP,
                        GetAddrInfoFlags => 0);
        $sockargs{LocalAddr} = $address if defined($address);
 
@@ -840,6 +839,72 @@ sub next_spice_port {
     return next_unused_port(61000, 61099, $family, $address);
 }
 
+# sigkill after $timeout  a $sub running in a fork if it can't write a pipe
+# the $sub has to return a single scalar
+sub run_fork_with_timeout {
+    my ($timeout, $sub) = @_;
+
+    my $res;
+    my $error;
+    my $pipe_out = IO::Pipe->new();
+    my $pipe_err = IO::Pipe->new();
+
+    # disable pending alarms, save their remaining time
+    my $prev_alarm = alarm 0;
+
+    # trap before forking to avoid leaving a zombie if the parent get killed
+    my $sig_received;
+    local $SIG{INT} = $SIG{TERM} = $SIG{QUIT} = $SIG{HUP} = $SIG{PIPE} = sub {
+       $sig_received++;
+    };
+
+    my $child = fork();
+    if (!defined($child)) {
+       die "fork failed: $!\n";
+       return $res;
+    }
+
+    if (!$child) {
+       $pipe_out->writer();
+       $pipe_err->writer();
+
+       eval {
+           $res = $sub->();
+           print {$pipe_out} "$res";
+           $pipe_out->flush();
+       };
+       if (my $err = $@) {
+           print {$pipe_err} "$err";
+           $pipe_err->flush();
+           POSIX::_exit(1);
+       }
+       POSIX::_exit(0);
+    }
+
+    $pipe_out->reader();
+    $pipe_err->reader();
+
+    my $readvalues = sub {
+       local $/ = undef;
+       $res = <$pipe_out>;
+       $error = <$pipe_err>;
+    };
+    eval {
+       run_with_timeout($timeout, $readvalues);
+    };
+    warn $@ if $@;
+    $pipe_out->close();
+    $pipe_err->close();
+    kill('KILL', $child);
+    waitpid($child, 0);
+
+    alarm $prev_alarm;
+    die "interrupted by unexpected signal\n" if $sig_received;
+
+    die $error if $error;
+    return $res;
+}
+
 # NOTE: NFS syscall can't be interrupted, so alarm does
 # not work to provide timeouts.
 # from 'man nfs': "Only SIGKILL can interrupt a pending NFS operation"