Merge pull request #7800 from VersatusHPC/refactor/dhcp-omapi-command-runner

refactor(dhcp): share OMAPI command runner

perl-xCAT/xCAT/DHCP/OmapiRunner.pm

@@ -0,0 +1,78 @@
+package xCAT::DHCP::OmapiRunner;
+
+use strict;
+use warnings;
+
+use File::Temp qw(tempfile);
+use POSIX qw(WNOHANG);
+use Time::HiRes qw(sleep);
+use xCAT::Utils;
+
+sub open_command_file {
+    my ($class, $directory) = @_;
+
+    $directory ||= $class->_command_directory();
+    mkdir $directory unless -d $directory;
+
+    my ($handle, $path) = tempfile('omshell.XXXXXX', DIR => $directory, UNLINK => 0);
+    return { handle => $handle, path => $path };
+}
+
+sub run_command_file {
+    my ( $class, $command_file, $omshell_path ) = @_;
+
+    my $pid = $class->_fork();
+    return 'fork_error' unless defined $pid;
+
+    if ( $pid == 0 ) {
+        open( STDIN,  '<', $command_file ) or exit 127;    ## no critic (InputOutput::RequireCheckedOpen)
+        open( STDOUT, '>', '/dev/null' ) or exit 127;      ## no critic (InputOutput::RequireCheckedOpen)
+        open( STDERR, '>', '/dev/null' ) or exit 127;      ## no critic (InputOutput::RequireCheckedOpen)
+        exec {$omshell_path} $omshell_path;
+        exit 127;
+    }
+
+    for ( 1 .. $class->_completion_attempts() ) {
+        if ( waitpid( $pid, WNOHANG ) == $pid ) {
+            sleep $class->_completion_delay();
+            return 'completed';
+        }
+        sleep $class->_poll_interval();
+    }
+
+    kill 'TERM', $pid;
+    for ( 1 .. $class->_termination_attempts() ) {
+        return 'terminated' if waitpid( $pid, WNOHANG ) == $pid;
+        sleep $class->_poll_interval();
+    }
+
+    kill 'KILL', $pid;
+    waitpid( $pid, 0 );
+    return 'killed';
+}
+
+sub _fork {
+    return xCAT::Utils->xfork();
+}
+
+sub _completion_attempts {
+    return 100;
+}
+
+sub _termination_attempts {
+    return 20;
+}
+
+sub _poll_interval {
+    return 0.1;
+}
+
+sub _completion_delay {
+    return 1.0;
+}
+
+sub _command_directory {
+    return '/tmp/xcat';
+}
+
+1;

xCAT-server/lib/xcat/plugins/dhcp.pm

@@ -11,7 +11,6 @@ use strict;
 use IPC::Open2;
 use IPC::Open3;
 use IO::Select;
-use File::Temp qw(tempfile);
 use Symbol qw/gensym/;
 use POSIX qw/WNOHANG/;
 use Time::HiRes qw(sleep);
@@ -36,6 +35,7 @@ use xCAT::SvrUtils;
 use xCAT::DHCP::BootPolicy;
 use xCAT::DHCP::Backend;
 use xCAT::DHCP::OmapiPolicy;
+use xCAT::DHCP::OmapiRunner;
 use xCAT::DHCP::Range;
 use xCAT::TableUtils;
 use xCAT::NetworkUtils qw/getipaddr/;
@@ -412,45 +412,10 @@ sub _open_omshell_writer
 {
     my $settings = shift;
 
-    mkdir "/tmp/xcat" unless -d "/tmp/xcat";
-    my ($omshell_stdin, $command_file) = tempfile('omshell.XXXXXX', DIR => '/tmp/xcat', UNLINK => 0);
-    return unless $omshell_stdin;
+    my $command = xCAT::DHCP::OmapiRunner->open_command_file();
+    return unless ref($command) eq 'HASH' && $command->{handle};
 
-    return ($omshell_stdin, { command_file => $command_file, omshell_path => $settings->{omshell_path} });
-}
-
-sub _run_omshell_command_file
-{
-    my ($command_file, $omshell_path) = @_;
-
-    my $pid = fork();
-    return unless defined $pid;
-
-    if ($pid == 0) {
-        open(STDIN, '<', $command_file) or exit 127;          ## no critic (InputOutput::RequireCheckedOpen)
-        open(STDOUT, '>', '/dev/null') or exit 127;           ## no critic (InputOutput::RequireCheckedOpen)
-        open(STDERR, '>', '/dev/null') or exit 127;           ## no critic (InputOutput::RequireCheckedOpen)
-        exec { $omshell_path } $omshell_path;
-        exit 127;
-    }
-
-    for (1 .. 100) {
-        if (waitpid($pid, WNOHANG) == $pid) {
-            sleep 1.0;
-            return 1;
-        }
-        sleep 0.1;
-    }
-
-    kill 'TERM', $pid;
-    for (1 .. 20) {
-        return if waitpid($pid, WNOHANG) == $pid;
-        sleep 0.1;
-    }
-
-    kill 'KILL', $pid;
-    waitpid($pid, 0);
-    return;
+    return ($command->{handle}, { command_file => $command->{path}, omshell_path => $settings->{omshell_path} });
 }
 
 sub _close_omshell_writer
@@ -461,9 +426,12 @@ sub _close_omshell_writer
 
     return unless ref($writer) eq 'HASH';
 
-    my $ok = _run_omshell_command_file($writer->{command_file}, $writer->{omshell_path});
+    my $status = xCAT::DHCP::OmapiRunner->run_command_file(
+        $writer->{command_file}, $writer->{omshell_path}
+    );
     unlink $writer->{command_file};
-    syslog("local4|err", "omshell did not complete while updating DHCP reservations") unless $ok;
+    syslog("local4|err", "omshell did not complete while updating DHCP reservations")
+      unless $status eq 'completed';
 }
 
 ######################################################

xCAT-server/share/xcat/tools/dhcpop

@@ -10,13 +10,9 @@ BEGIN
 use lib "$::XCATROOT/lib/perl";
 
 use Getopt::Long;
-use File::Temp qw(tempfile);
 use Fcntl ':flock';
-use IPC::Open3;
-use POSIX qw/WNOHANG/;
-use Symbol qw/gensym/;
-use Time::HiRes qw(sleep);
 use xCAT::DHCP::OmapiPolicy;
+use xCAT::DHCP::OmapiRunner;
 use xCAT::Table;
 
 sub usage{
@@ -146,41 +142,17 @@ if($help){
        $omshell_commands .= "close\n";
     }
 
-    mkdir "/tmp/xcat" unless -d "/tmp/xcat";
-    my ($omshell, $command_file) = tempfile('omshell.XXXXXX', DIR => '/tmp/xcat', UNLINK => 0);
+    my $command = xCAT::DHCP::OmapiRunner->open_command_file();
+    my $omshell = ref($command) eq 'HASH' ? $command->{handle} : undef;
     die "Unable to start omshell: $!" unless $omshell;
     print $omshell $omshell_commands;
     close($omshell);
 
-    my $pid = fork();
-    die "Unable to start omshell: $!" unless defined $pid;
-    if ($pid == 0) {
-        open(STDIN, '<', $command_file) or exit 127;          ## no critic (InputOutput::RequireCheckedOpen)
-        open(STDOUT, '>', '/dev/null') or exit 127;           ## no critic (InputOutput::RequireCheckedOpen)
-        open(STDERR, '>', '/dev/null') or exit 127;           ## no critic (InputOutput::RequireCheckedOpen)
-        exec { $settings->{omshell_path} } $settings->{omshell_path};
-        exit 127;
-    }
-
-    for (1 .. 100) {
-        if (waitpid($pid, WNOHANG) == $pid) {
-            sleep 1.0;
-            unlink $command_file;
-            exit 0;
-        }
-        sleep 0.1;
-    }
-    kill 'TERM', $pid;
-    for (1 .. 20) {
-        if (waitpid($pid, WNOHANG) == $pid) {
-            unlink $command_file;
-            exit 0;
-        }
-        sleep 0.1;
-    }
-    kill 'KILL', $pid;
-    waitpid($pid, 0);
-    unlink $command_file;
+    my $status = xCAT::DHCP::OmapiRunner->run_command_file(
+        $command->{path}, $settings->{omshell_path}
+    );
+    die "Unable to start omshell: $!" if $status eq 'fork_error';
+    unlink $command->{path};
 }else{
     &usage;
     exit 1;

xCAT-test/unit/dhcp_omapi_runner.t

@@ -0,0 +1,294 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use FindBin;
+use lib "$FindBin::Bin/../../perl-xCAT";
+
+use Config;
+use Errno qw(EAGAIN);
+use File::Spec;
+use File::Temp qw(tempdir);
+use Test::More;
+
+use xCAT::DHCP::OmapiRunner;
+
+{
+    package XCAT::Test::FastOmapiRunner;
+    use parent 'xCAT::DHCP::OmapiRunner';
+
+    our $COMMAND_DIRECTORY;
+
+    sub _completion_attempts {
+        return 1000;
+    }
+
+    sub _termination_attempts {
+        return 100;
+    }
+
+    sub _poll_interval {
+        return 0.01;
+    }
+
+    sub _completion_delay {
+        return 0.01;
+    }
+
+    sub _command_directory {
+        my $class = shift;
+        return $COMMAND_DIRECTORY || $class->SUPER::_command_directory();
+    }
+}
+
+{
+    package XCAT::Test::ReadyOmapiRunner;
+    use parent -norequire, 'XCAT::Test::FastOmapiRunner';
+    use POSIX qw(WNOHANG);
+    use Time::HiRes qw(sleep);
+
+    our $READY_MARKER;
+    our $COMPLETION_ATTEMPTS  = 10;
+    our $TERMINATION_ATTEMPTS = 1000;
+
+    sub _fork {
+        my $pid = fork();
+        return $pid unless $pid;
+
+        for ( 1 .. 1000 ) {
+            return $pid if $READY_MARKER && -f $READY_MARKER;
+            die 'OMAPI test child exited before reaching its ready state'
+              if waitpid( $pid, WNOHANG ) == $pid;
+            sleep 0.01;
+        }
+
+        kill 'KILL', $pid;
+        waitpid( $pid, 0 );
+        die 'OMAPI test child did not reach its ready state';
+    }
+
+    sub _completion_attempts {
+        return $COMPLETION_ATTEMPTS;
+    }
+
+    sub _termination_attempts {
+        return $TERMINATION_ATTEMPTS;
+    }
+}
+
+{
+    package XCAT::Test::ForkErrorOmapiRunner;
+    use parent -norequire, 'XCAT::Test::FastOmapiRunner';
+    use Errno qw(EAGAIN);
+
+    sub _fork {
+        $! = EAGAIN;
+        return;
+    }
+}
+
+{
+    package XCAT::Test::InheritedDatabaseHandle;
+
+    sub new {
+        my ( $class, $marker ) = @_;
+        return bless { marker => $marker }, $class;
+    }
+
+    sub DESTROY {
+        my ($self) = @_;
+        return if $self->{InactiveDestroy};
+
+        open( my $fh, '>', $self->{marker} ) or die "Unable to create $self->{marker}: $!";
+        print {$fh} "destroyed\n" or die "Unable to write $self->{marker}: $!";
+        close($fh) or die "Unable to close $self->{marker}: $!";
+    }
+}
+
+sub write_executable {
+    my ( $path, $contents ) = @_;
+
+    open( my $fh, '>', $path ) or die "Unable to create $path: $!";
+    print {$fh} $contents or die "Unable to write $path: $!";
+    close($fh) or die "Unable to close $path: $!";
+    chmod 0755, $path or die "Unable to make $path executable: $!";
+}
+
+sub write_command_file {
+    my ( $directory, $contents ) = @_;
+
+    my $command = XCAT::Test::FastOmapiRunner->open_command_file($directory);
+    print { $command->{handle} } $contents or die "Unable to write $command->{path}: $!";
+    close( $command->{handle} ) or die "Unable to close $command->{path}: $!";
+    return $command->{path};
+}
+
+sub cleanup_command_file {
+    my ($path) = @_;
+
+    unlink($path) or die "Unable to remove $path: $!";
+}
+
+my $workspace = tempdir( CLEANUP => 1 );
+my $command_directory = File::Spec->catdir( $workspace, 'commands' );
+my $capture = File::Spec->catfile( $workspace, 'captured-input' );
+my $success = File::Spec->catfile( $workspace, 'success' );
+
+my $default_command;
+{
+    local $XCAT::Test::FastOmapiRunner::COMMAND_DIRECTORY = $command_directory;
+    $default_command = XCAT::Test::FastOmapiRunner->open_command_file();
+}
+is( ref($default_command), 'HASH', 'the command file is returned as a named record' );
+ok( $default_command->{handle}, 'the command record includes its writable handle' );
+like(
+    $default_command->{path},
+    qr{\A\Q$command_directory\E/omshell\.},
+    'omitting the directory uses the configured command directory'
+);
+close( $default_command->{handle} ) or die "Unable to close $default_command->{path}: $!";
+unlink $default_command->{path} or die "Unable to remove $default_command->{path}: $!";
+
+write_executable(
+    $success,
+    <<"SCRIPT"
+#!$Config{perlpath}
+use strict;
+use warnings;
+my \$contents = do { local \$/; <STDIN> };
+open(my \$fh, '>', \$ENV{OMAPI_TEST_CAPTURE}) or die \$!;
+print {\$fh} \$contents or die \$!;
+close(\$fh) or die \$!;
+print "discarded stdout\n";
+warn "discarded stderr\n";
+SCRIPT
+);
+
+my $command_file = write_command_file( $command_directory, "connect\nclose\n" );
+ok( -d $command_directory, 'the command directory is created when absent' );
+ok( -f $command_file, 'a persistent command file is created for omshell' );
+
+local $ENV{OMAPI_TEST_CAPTURE} = $capture;
+my $parent_stdout = File::Spec->catfile( $workspace, 'parent-stdout' );
+my $parent_stderr = File::Spec->catfile( $workspace, 'parent-stderr' );
+my $success_status;
+my ( $success_ok, $success_error );
+{
+    open( my $saved_stdout, '>&', \*STDOUT ) or die "Unable to preserve stdout: $!";
+    open( my $saved_stderr, '>&', \*STDERR ) or die "Unable to preserve stderr: $!";
+    open( STDOUT, '>', $parent_stdout ) or die "Unable to create $parent_stdout: $!";
+    open( STDERR, '>', $parent_stderr ) or die "Unable to create $parent_stderr: $!";
+    $success_ok = eval {
+        $success_status = XCAT::Test::FastOmapiRunner->run_command_file( $command_file, $success );
+        1;
+    };
+    $success_error = $@;
+    open( STDOUT, '>&', $saved_stdout ) or die "Unable to restore stdout: $!";
+    open( STDERR, '>&', $saved_stderr ) or die "Unable to restore stderr: $!";
+    close($saved_stdout) or die "Unable to close preserved stdout: $!";
+    close($saved_stderr) or die "Unable to close preserved stderr: $!";
+}
+die $success_error unless $success_ok;
+is( $success_status, 'completed', 'a normally exiting command is reported as completed' );
+
+open( my $capture_fh, '<', $capture ) or die "Unable to read $capture: $!";
+my $captured = do { local $/; <$capture_fh> };
+close($capture_fh) or die "Unable to close $capture: $!";
+is( $captured, "connect\nclose\n", 'the command file is connected to child stdin' );
+is( -s $parent_stdout, 0, 'child stdout is redirected away from the caller' );
+is( -s $parent_stderr, 0, 'child stderr is redirected away from the caller' );
+ok( -e $command_file, 'the runner leaves cleanup timing to its caller' );
+cleanup_command_file($command_file);
+
+my $child_database_cleanup = File::Spec->catfile( $workspace, 'child-database-cleanup' );
+$command_file = write_command_file( $command_directory, "connect\n" );
+{
+    local $::XCAT_DBHS = {
+        inherited => XCAT::Test::InheritedDatabaseHandle->new($child_database_cleanup),
+    };
+    is(
+        XCAT::Test::FastOmapiRunner->run_command_file(
+            $command_file, File::Spec->catfile( $workspace, 'missing-omshell' )
+        ),
+        'completed',
+        'legacy exec failure remains a completed child process'
+    );
+    ok( !-e $child_database_cleanup, 'exec failure does not destroy an inherited database handle' );
+    $::XCAT_DBHS->{inherited}->{InactiveDestroy} = 1;
+}
+cleanup_command_file($command_file);
+
+$command_file = write_command_file( $command_directory, "connect\n" );
+$! = 0;
+my $fork_status = XCAT::Test::ForkErrorOmapiRunner->run_command_file( $command_file, $success );
+my $fork_errno = 0 + $!;
+is( $fork_status, 'fork_error', 'fork failure is reported separately from child completion' );
+is( $fork_errno, EAGAIN, 'fork failure leaves the operating-system error available to the caller' );
+ok( -e $command_file, 'fork failure preserves caller-owned cleanup ordering' );
+cleanup_command_file($command_file);
+
+my $term_marker = File::Spec->catfile( $workspace, 'term-seen' );
+my $term_ready = File::Spec->catfile( $workspace, 'term-ready' );
+my $term_aware = File::Spec->catfile( $workspace, 'term-aware' );
+write_executable(
+    $term_aware,
+    <<"SCRIPT"
+#!$Config{perlpath}
+use strict;
+use warnings;
+\$SIG{TERM} = sub {
+    open(my \$fh, '>', \$ENV{OMAPI_TEST_MARKER}) or die \$!;
+    print {\$fh} "TERM\n" or die \$!;
+    close(\$fh) or die \$!;
+    exit 0;
+};
+open(my \$ready_fh, '>', \$ENV{OMAPI_TEST_READY}) or die \$!;
+print {\$ready_fh} "ready\n" or die \$!;
+close(\$ready_fh) or die \$!;
+do { local \$/; <STDIN> };
+while (1) { select undef, undef, undef, 0.1; }
+SCRIPT
+);
+
+$command_file = write_command_file( $command_directory, "connect\n" );
+my $term_status;
+{
+    local $ENV{OMAPI_TEST_MARKER} = $term_marker;
+    local $ENV{OMAPI_TEST_READY} = $term_ready;
+    local $XCAT::Test::ReadyOmapiRunner::READY_MARKER = $term_ready;
+    $term_status = XCAT::Test::ReadyOmapiRunner->run_command_file( $command_file, $term_aware );
+}
+is( $term_status, 'terminated', 'a hung command that handles TERM is reported as terminated' );
+ok( -f $term_marker, 'the timed-out command receives TERM before any KILL' );
+cleanup_command_file($command_file);
+
+my $kill_ready = File::Spec->catfile( $workspace, 'kill-ready' );
+my $term_ignoring = File::Spec->catfile( $workspace, 'term-ignoring' );
+write_executable(
+    $term_ignoring,
+    <<"SCRIPT"
+#!$Config{perlpath}
+use strict;
+use warnings;
+\$SIG{TERM} = 'IGNORE';
+open(my \$fh, '>', \$ENV{OMAPI_TEST_READY}) or die \$!;
+print {\$fh} "ready\n" or die \$!;
+close(\$fh) or die \$!;
+do { local \$/; <STDIN> };
+while (1) { select undef, undef, undef, 0.1; }
+SCRIPT
+);
+
+$command_file = write_command_file( $command_directory, "connect\n" );
+my $kill_status;
+{
+    local $ENV{OMAPI_TEST_READY} = $kill_ready;
+    local $XCAT::Test::ReadyOmapiRunner::READY_MARKER = $kill_ready;
+    local $XCAT::Test::ReadyOmapiRunner::TERMINATION_ATTEMPTS = 10;
+    $kill_status = XCAT::Test::ReadyOmapiRunner->run_command_file( $command_file, $term_ignoring );
+}
+is( $kill_status, 'killed', 'a hung command that ignores TERM is reported as killed' );
+ok( -f $kill_ready, 'the TERM-ignoring command reached its wait state before KILL' );
+cleanup_command_file($command_file);
+
+done_testing();

xCAT-test/unit/dhcp_omapi_runner_callers.t

@@ -0,0 +1,307 @@
+#!/usr/bin/env perl
+use strict;
+use warnings;
+
+use FindBin;
+use lib "$FindBin::Bin/../lib";
+use lib "$FindBin::Bin/../../xCAT-server/lib/perl";
+use lib "$FindBin::Bin/../../perl-xCAT";
+
+use Config;
+use File::Path qw(make_path);
+use File::Spec;
+use File::Temp qw(tempdir);
+use IPC::Open3;
+use Symbol qw(gensym);
+use Test::More;
+
+use XCAT::Test::File qw(repo_path);
+use xCAT::DHCP::OmapiRunner;
+
+$ENV{XCATCFG} ||= 'SQLite:/tmp';
+
+my $source_dhcp_plugin = repo_path('xCAT-server/lib/xcat/plugins/dhcp.pm');
+require $source_dhcp_plugin;
+
+sub write_file {
+    my ( $path, $contents ) = @_;
+
+    open( my $fh, '>', $path ) or die "Unable to create $path: $!";
+    print {$fh} $contents or die "Unable to write $path: $!";
+    close($fh) or die "Unable to close $path: $!";
+}
+
+sub read_file {
+    my ($path) = @_;
+
+    open( my $fh, '<', $path ) or die "Unable to read $path: $!";
+    my $contents = do { local $/; <$fh> };
+    close($fh) or die "Unable to close $path: $!";
+    return $contents;
+}
+
+my $workspace = tempdir( CLEANUP => 1 );
+my $plugin_command_directory = File::Spec->catdir( $workspace, 'plugin-commands' );
+
+{
+    my $command = xCAT::DHCP::OmapiRunner->open_command_file($plugin_command_directory);
+    my @open_arguments;
+    my ( $handle, $writer );
+
+    {
+        no warnings qw(once redefine);
+        local *xCAT::DHCP::OmapiRunner::open_command_file = sub {
+            my ( $class, @arguments ) = @_;
+            @open_arguments = @arguments;
+            return $command;
+        };
+        ( $handle, $writer ) = xCAT_plugin::dhcp::_open_omshell_writer(
+            { omshell_path => '/usr/bin/omshell' }
+        );
+    }
+
+    is_deeply( \@open_arguments, [], 'makedhcp uses the runner default command directory' );
+    is( fileno($handle), fileno( $command->{handle} ), 'makedhcp returns the runner command handle' );
+    is_deeply(
+        $writer,
+        { command_file => $command->{path}, omshell_path => '/usr/bin/omshell' },
+        'makedhcp retains the command path and omshell executable for closing'
+    );
+    close($handle) or die "Unable to close $command->{path}: $!";
+    unlink $command->{path} or die "Unable to remove $command->{path}: $!";
+}
+
+foreach my $status (qw(completed terminated killed fork_error)) {
+    subtest "makedhcp handles $status" => sub {
+        my $command = xCAT::DHCP::OmapiRunner->open_command_file($plugin_command_directory);
+        my @logs;
+        my @run_arguments;
+        my $run_contents;
+        my $writer_closed_before_run;
+
+        print { $command->{handle} } "connect\n" or die "Unable to write $command->{path}: $!";
+
+        {
+            no warnings qw(once redefine);
+            local *xCAT::DHCP::OmapiRunner::run_command_file = sub {
+                my ( $class, @arguments ) = @_;
+                @run_arguments = @arguments;
+                $writer_closed_before_run = !defined fileno( $command->{handle} );
+                $run_contents = read_file( $arguments[0] );
+                return $status;
+            };
+            local *xCAT_plugin::dhcp::syslog = sub { push @logs, [@_]; };
+            xCAT_plugin::dhcp::_close_omshell_writer(
+                $command->{handle},
+                { command_file => $command->{path}, omshell_path => '/usr/bin/omshell' }
+            );
+        }
+
+        is_deeply(
+            \@run_arguments,
+            [ $command->{path}, '/usr/bin/omshell' ],
+            'makedhcp passes the command path and executable in order'
+        );
+        ok( $writer_closed_before_run, 'makedhcp closes the command file before the runner reads it' );
+        is( $run_contents, "connect\n", 'makedhcp flushes the command file before the runner reads it' );
+        ok( !-e $command->{path}, 'makedhcp removes the command file after the runner returns' );
+        if ( $status eq 'completed' ) {
+            is_deeply( \@logs, [], 'makedhcp does not log a completed command' );
+        } else {
+            is_deeply(
+                \@logs,
+                [ [ 'local4|err', 'omshell did not complete while updating DHCP reservations' ] ],
+                'makedhcp logs a non-completed command once'
+            );
+        }
+    };
+}
+
+my $fake_root = File::Spec->catdir( $workspace, 'fake-xcat' );
+my $fake_perl = File::Spec->catdir( $fake_root, 'lib', 'perl' );
+my $fake_dhcp = File::Spec->catdir( $fake_perl, 'xCAT', 'DHCP' );
+my $dhcpop_command_directory = File::Spec->catdir( $workspace, 'dhcpop-commands' );
+make_path( $fake_dhcp, $dhcpop_command_directory );
+
+write_file(
+    File::Spec->catfile( $fake_dhcp, 'Backend.pm' ),
+    <<'MODULE'
+package xCAT::DHCP::Backend;
+use strict;
+use warnings;
+
+sub new_backend {
+    return bless {}, __PACKAGE__;
+}
+
+sub name {
+    return 'isc';
+}
+
+1;
+MODULE
+);
+
+write_file(
+    File::Spec->catfile( $fake_dhcp, 'OmapiPolicy.pm' ),
+    <<'MODULE'
+package xCAT::DHCP::OmapiPolicy;
+use strict;
+use warnings;
+
+sub settings {
+    return { key_name => 'omapi', omshell_path => '/usr/bin/omshell' };
+}
+
+sub omshell_preamble {
+    return "server 127.0.0.1\n";
+}
+
+1;
+MODULE
+);
+
+write_file(
+    File::Spec->catfile( $fake_perl, 'xCAT', 'Table.pm' ),
+    <<'MODULE'
+package xCAT::Table;
+use strict;
+use warnings;
+
+sub new {
+    my $class = shift;
+    return bless {}, $class;
+}
+
+sub getAttribs {
+    return { password => 'secret' };
+}
+
+1;
+MODULE
+);
+
+write_file(
+    File::Spec->catfile( $fake_dhcp, 'OmapiRunner.pm' ),
+    <<'MODULE'
+package xCAT::DHCP::OmapiRunner;
+use strict;
+use warnings;
+
+use Errno qw(EAGAIN);
+use File::Temp qw(tempfile);
+
+sub open_command_file {
+    my ( $class, @arguments ) = @_;
+    open( my $arguments, '>', $ENV{OMAPI_TEST_OPEN_ARGUMENTS} ) or die $!;
+    print {$arguments} join("\n", @arguments) or die $!;
+    close($arguments) or die $!;
+    my ( $handle, $path ) = tempfile(
+        'omshell.XXXXXX',
+        DIR    => $ENV{OMAPI_TEST_COMMAND_DIRECTORY},
+        UNLINK => 0,
+    );
+    open( my $record, '>', $ENV{OMAPI_TEST_PATH_RECORD} ) or die $!;
+    print {$record} $path or die $!;
+    close($record) or die $!;
+    return { handle => $handle, path => $path };
+}
+
+sub run_command_file {
+    my ( $class, $path, $omshell_path ) = @_;
+    open( my $command, '<', $path ) or die $!;
+    my $contents = do { local $/; <$command> };
+    close($command) or die $!;
+    open( my $capture, '>', $ENV{OMAPI_TEST_CAPTURE} ) or die $!;
+    print {$capture} $contents or die $!;
+    close($capture) or die $!;
+    open( my $omshell_capture, '>', $ENV{OMAPI_TEST_OMSHELL_CAPTURE} ) or die $!;
+    print {$omshell_capture} $omshell_path or die $!;
+    close($omshell_capture) or die $!;
+    $! = EAGAIN if $ENV{OMAPI_TEST_STATUS} eq 'fork_error';
+    return $ENV{OMAPI_TEST_STATUS};
+}
+
+1;
+MODULE
+);
+
+my $dhcpop = repo_path('xCAT-server/share/xcat/tools/dhcpop');
+
+sub run_dhcpop {
+    my ($status) = @_;
+    my $capture = File::Spec->catfile( $workspace, "dhcpop-$status-capture" );
+    my $open_arguments = File::Spec->catfile( $workspace, "dhcpop-$status-open-arguments" );
+    my $omshell_capture = File::Spec->catfile( $workspace, "dhcpop-$status-omshell" );
+    my $path_record = File::Spec->catfile( $workspace, "dhcpop-$status-path" );
+
+    local $ENV{XCATROOT} = $fake_root;
+    local $ENV{OMAPI_TEST_CAPTURE} = $capture;
+    local $ENV{OMAPI_TEST_COMMAND_DIRECTORY} = $dhcpop_command_directory;
+    local $ENV{OMAPI_TEST_OPEN_ARGUMENTS} = $open_arguments;
+    local $ENV{OMAPI_TEST_OMSHELL_CAPTURE} = $omshell_capture;
+    local $ENV{OMAPI_TEST_PATH_RECORD} = $path_record;
+    local $ENV{OMAPI_TEST_STATUS} = $status;
+
+    my ( $child_in, $child_out );
+    my $child_err = gensym;
+    my $pid = open3(
+        $child_in,
+        $child_out,
+        $child_err,
+        $Config{perlpath},
+        $dhcpop,
+        '-r',
+        '-n',
+        'node01',
+    );
+    close($child_in);
+    my $stdout = do { local $/; <$child_out> } // '';
+    my $stderr = do { local $/; <$child_err> } // '';
+    waitpid( $pid, 0 );
+    my $exit_status = $? >> 8;
+    my $command_path = read_file($path_record);
+
+    return {
+        command        => read_file($capture),
+        command_path   => $command_path,
+        exit_status    => $exit_status,
+        open_arguments => read_file($open_arguments),
+        omshell_path   => read_file($omshell_capture),
+        stderr         => $stderr,
+        stdout         => $stdout,
+    };
+}
+
+my $expected_command = <<'COMMAND';
+server 127.0.0.1
+connect
+new host
+set name = "node01"
+open
+remove
+close
+COMMAND
+
+foreach my $status (qw(completed terminated killed fork_error)) {
+    subtest "dhcpop handles $status" => sub {
+        my $result = run_dhcpop($status);
+
+        is( $result->{command}, $expected_command, 'dhcpop sends the expected OMAPI commands' );
+        is( $result->{open_arguments}, '', 'dhcpop uses the runner default command directory' );
+        is( $result->{omshell_path}, '/usr/bin/omshell', 'dhcpop passes the configured executable' );
+        is( $result->{stdout}, '', 'dhcpop does not write to stdout' );
+        if ( $status eq 'fork_error' ) {
+            isnt( $result->{exit_status}, 0, 'dhcpop fails when the runner cannot fork' );
+            like( $result->{stderr}, qr/Unable to start omshell:/, 'dhcpop reports the fork failure' );
+            ok( -e $result->{command_path}, 'dhcpop preserves its legacy fork-failure cleanup ordering' );
+            unlink $result->{command_path} or die "Unable to remove $result->{command_path}: $!";
+        } else {
+            is( $result->{exit_status}, 0, "dhcpop accepts the $status runner result" );
+            is( $result->{stderr}, '', 'dhcpop does not report an accepted runner result' );
+            ok( !-e $result->{command_path}, 'dhcpop removes the command file after an accepted result' );
+        }
+    };
+}
+
+done_testing();