/usr/share/polymake/perllib/Polymake/Background.pm is in polymake-common 3.2r2-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 | # Copyright (c) 1997-2018
# Ewgenij Gawrilow, Michael Joswig (Technische Universitaet Berlin, Germany)
# http://www.polymake.org
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2, or (at your option) any
# later version: http://www.gnu.org/licenses/gpl.txt.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#-------------------------------------------------------------------------------
use strict;
use namespaces;
use warnings qw(FATAL void syntax misc);
package Polymake::Background;
use POSIX qw( :sys_wait_h );
my %active; # pid => something to destroy on termination
my $init;
sub gather_zombies {
my $flag=shift // 0;
if (!$flag) {
foreach (grep { ref($_) eq "CODE" } values %active) {
eval { $_->() };
if ($@) {
warn_print( "cleanup after background process failed: $@\n" );
}
}
}
while (keys(%active) && (my $pid=waitpid(-1, $flag)) > 0) {
delete $active{$pid};
}
}
sub wait_for_active {
my $rc=0;
foreach my $pid (keys %active) {
waitpid($pid, 0);
$rc ||= $?;
delete $active{$pid};
}
return $rc;
}
sub add_process {
if ($init) {
gather_zombies(WNOHANG);
} else {
add AtEnd("Background", \&gather_zombies, before => "tempdir");
$init=1;
}
$active{$_[0]}=$_[1];
}
package Polymake::Background::Process;
sub new {
shift;
my $options=shift if ref($_[0]) eq "HASH";
my ($cleanup, $redirect);
if ($options) {
$cleanup=delete $options->{CLEANUP};
$redirect=delete $options->{REDIRECT};
if (keys %$options) {
croak( "unknown option(s) for Background::Process: ", join(",", keys %$options) );
}
}
my $pid=launch($redirect, 1, @_);
add_process($pid, $cleanup);
return $pid;
}
sub launch {
my ($redirect, $hide, @cmdline)=@_;
dbg_print( "starting @cmdline" ) if $Verbose::external;
my $pid=fork;
if (!$pid) {
die "Background::Process: fork failed: $!\n" if !defined($pid);
if (defined($redirect)) {
POSIX::dup2(fileno($redirect->[0]), 0);
POSIX::dup2(fileno($redirect->[1]), 1);
} else {
STDIN->close;
}
if ($hide) {
POSIX::setsid();
$SIG{INT}='IGNORE';
$SIG{ALRM}='IGNORE';
}
if (ref($cmdline[0]) eq "ARRAY") {
# internal subprocess: [ \&sub, leading arguments ], further arguments
my $lead=shift @cmdline;
my $sub=shift @$lead;
if (ref($sub) eq "CODE") {
eval { $sub->(@$lead, @cmdline) };
} else {
$@="wrong use: a CODE reference expected\n";
}
if ($@) {
print STDERR "internal subprocess terminated with an error: $@";
POSIX::_exit(1);
} else {
POSIX::_exit(0); # avoid executing global destructors
}
} else {
exec "@cmdline"
or do {
my ($progname)= @cmdline==1 ? $cmdline[0] =~ /^\s*(\S+)/ : @cmdline;
print STDERR "could not start $progname: $!\n";
POSIX::_exit(1); # avoid executing global destructors
}
}
}
return $pid;
}
package Polymake::Background::Pipe;
use Symbol 'gensym';
use POSIX ':fcntl_h';
# "command", "args" ... => IN handle, OUT handle, PID
sub new {
shift;
my @handles=(gensym, gensym);
my @pipends=(gensym, gensym);
pipe $pipends[0], $handles[1];
pipe $handles[0], $pipends[1];
fcntl($_, F_SETFD, FD_CLOEXEC) for (@pipends, @handles);
my $pid=Process::launch(\@pipends, 0, @_);
$handles[1]->autoflush;
(@handles, $pid);
}
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