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Correct check for failed forks #65

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Correct check for failed forks #65

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18 changes: 9 additions & 9 deletions lib/Daemon/Control.pm
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Original file line number Diff line number Diff line change
Expand Up @@ -188,10 +188,14 @@ sub _double_fork {
my $pid = fork();

$self->trace( "_double_fork()" );
if ( $pid == 0 ) { # Child, launch the process here.
if ( not defined $pid ) { # We couldn't fork. =(
die "Cannot fork: $!";
} elsif ( $pid == 0 ) { # Child, launch the process here.
setsid(); # Become the process leader.
my $new_pid = fork();
if ( $new_pid == 0 ) { # Our double fork.
if ( not defined $new_pid ) {
die "Cannot fork: $!";
} elsif ( $new_pid == 0 ) { # Our double fork.

if ( $self->gid ) {
setgid( $self->gid );
Expand Down Expand Up @@ -221,16 +225,12 @@ sub _double_fork {
}

$self->_launch_program;
} elsif ( not defined $new_pid ) {
warn "Cannot fork: $!";
} else {
$self->pid( $new_pid );
$self->trace("Set PID => $new_pid" );
$self->write_pid;
_exit 0;
}
} elsif ( not defined $pid ) { # We couldn't fork. =(
warn "Cannot fork: $!";
} else { # In the parent, $pid = child's PID, return it.
waitpid( $pid, 0 );
}
Expand All @@ -244,10 +244,10 @@ sub _fork {
my $pid = fork();

$self->trace( "_fork()" );
if ( $pid == 0 ) { # Child, launch the process here.
if ( not defined $pid ) {
die "Cannot fork: $!";
} elsif ( $pid == 0 ) { # Child, launch the process here.
$self->_launch_program;
} elsif ( not defined $pid ) {
warn "Cannot fork: $!";
} else { # In the parent, $pid = child's PID, return it.
$self->pid( $pid );
$self->trace("Set PID => $pid" );
Expand Down
40 changes: 40 additions & 0 deletions t/05_fork_fail.t
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Original file line number Diff line number Diff line change
@@ -0,0 +1,40 @@
#!/usr/bin/perl
use warnings;
use strict;

use Errno qw(EAGAIN);
use File::Temp qw(tempfile);
use Test::More;

# Simulate failing forks in the Daemon::Control package only
BEGIN {
*CORE::GLOBAL::fork = sub {
if ((caller)[0] eq 'Daemon::Control') {
$! = EAGAIN;
undef;
} else {
CORE::fork;
}
};
}

my(undef,$pidfile) = tempfile(SUFFIX => '_Daemon_Control.pid', UNLINK => 1);
my(undef,$outfile) = tempfile(SUFFIX => '_Daemon_Control.txt', UNLINK => 1);
unlink $outfile;

use_ok 'Daemon::Control';

eval {
Daemon::Control->new(
name => "failing_fork_test",
program => "/bin/sh",
program_args => ['-c', "echo this should not happen > $outfile"],
pid_file => $pidfile,
fork => 1,
)->run_command('start');
};
like $@, qr{Cannot fork};

ok !-e $outfile, 'daemon was not called';

done_testing;