X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=grading%2Fthreads%2Frun-tests;h=462a1ba0e3330eb783b9914531f2da58b84a96a2;hb=2f99a0445e1ca3643e6f1157b39e9c6a2bfcc34e;hp=f40e0d814a0a3d80181f311070d8c7dc61b695ac;hpb=3ae76eb4de24c4c3d8d715d3a5b09786bfb938a9;p=pintos-anon diff --git a/grading/threads/run-tests b/grading/threads/run-tests index f40e0d8..462a1ba 100755 --- a/grading/threads/run-tests +++ b/grading/threads/run-tests @@ -1,15 +1,148 @@ -#! /usr/bin/perl -w +#! /usr/bin/perl +use warnings; +use strict; use POSIX; -use Text::Diff; +use Algorithm::Diff; +use Getopt::Long; + +our ($VERBOSE) = 0; # Verbosity of output +our (@TESTS); # Tests to run. +my ($clean) = 0; +my ($grade) = 0; + +GetOptions ("v|verbose+" => \$VERBOSE, + "h|help" => sub { usage (0) }, + "t|test=s" => \@TESTS, + "c|clean" => \$clean, + "g|grade" => \$grade) + or die "Malformed command line; use --help for help.\n"; +die "Non-option argument not supported; use --help for help.\n" + if @ARGV > 0; + +sub usage { + my ($exitcode) = @_; + print "run-tests, for grading Pintos thread projects.\n\n"; + print "Invoke from a directory containing a student tarball named by\n"; + print "the submit script, e.g. username.Oct.12.04.20.04.09.tar.gz.\n"; + print "In normal usage, no options are needed.\n\n"; + print "Output is produced in tests.out and details.out.\n\n"; + print "Options:\n"; + print " -c, --clean Remove old output files before starting\n"; + print " -t, --test=TEST Execute TEST only (allowed multiple times)\n"; + print " -g, --grade Instead of running tests, compose grade.out\n"; + print " -v, --verbose Print commands before executing them\n"; + print " -h, --help Print this help message\n"; + exit $exitcode; +} + +# Default set of tests. +@TESTS = ("alarm-single", "alarm-multiple", "alarm-zero", "alarm-negative", + "join-simple", + "join-quick", "join-multiple", "join-nested", + "join-dummy", "join-invalid", "join-no", + "priority-preempt", "priority-fifo", "priority-donate-one", + "priority-donate-multiple", "priority-donate-nest", + "mlfqs-on", "mlfqs-off") + unless @TESTS > 0; + +# Handle final grade mode. +if ($grade) { + open (OUT, ">grade.out") or die "grade.out: create: $!\n"; + + open (GRADE, ") { + last if /^\s*$/; + print OUT; + } + close (GRADE); + + my (@tests) = snarf ("tests.out"); + my ($p_got, $p_pos) = $tests[0] =~ m%\((\d+)/(\d+)\)% or die; + + my (@review) = snarf ("review.txt"); + my ($part_lost) = (0, 0); + for (my ($i) = $#review; $i >= 0; $i--) { + local ($_) = $review[$i]; + if (my ($loss) = /^\s*([-+]\d+)/) { + $part_lost += $loss; + } elsif (my ($out_of) = m%\[\[/(\d+)\]\]%) { + my ($got) = $out_of + $part_lost; + $got = 0 if $got < 0; + $review[$i] =~ s%\[\[/\d+\]\]%($got/$out_of)% or die; + $part_lost = 0; + + $p_got += $got; + $p_pos += $out_of; + } + } + die "Lost points outside a section\n" if $part_lost; + + for (my ($i) = 1; $i <= $#review; $i++) { + if ($review[$i] =~ /^-{3,}\s*$/ && $review[$i - 1] !~ /^\s*$/) { + $review[$i] = '-' x (length ($review[$i - 1])); + } + } + + print OUT "\nOVERALL SCORE\n"; + print OUT "-------------\n"; + print OUT "$p_got points out of $p_pos total\n\n"; -$verbose = 0; + print OUT map ("$_\n", @tests), "\n"; + print OUT map ("$_\n", @review); + + exit 0; +} + +# Find the directory that contains the grading files. +our ($GRADES_DIR); ($GRADES_DIR = $0) =~ s#/[^/]+$##; -d $GRADES_DIR or die "$GRADES_DIR: stat: $!\n"; +if ($clean) { + # Verify that we're roughly in the correct directory + # before we go blasting away files. + choose_tarball (); + + xsystem ("rm -rf output pintos", VERBOSE => 1); + xsystem ("rm -f details.out tests.out", VERBOSE => 1); +} + +# Create output directory, if it doesn't already exist. -d ("output") || mkdir ("output") or die "output: mkdir: $!\n"; -if (! -d "pintos") { +# Extract submission. +extract_tarball () if ! -d "pintos"; + +# Verify that the proper directory was submitted. +-d "pintos/src/threads" or die "pintos/src/threads: stat: $!\n"; + +# Run and grade the tests. +our $test; +our %result; +our %details; +our %extra; +for $test (@TESTS) { + print "$test: "; + my ($result) = run_test ($test); + if ($result eq 'ok') { + $result = grade_test ($test); + $result =~ s/\n$//; + } + print "$result\n"; + + $result{$test} = $result; +} + +# MLFQS takes results from mlfqs-on and mlfqs-off. +grade_mlfqs_speedup (); +grade_mlfqs_priority (); + +# Write output. +write_grades (); +write_details (); + +sub choose_tarball { my (@tarballs) = grep (/^[a-z0-9]+\.[A-Za-z]+\.\d+\.\d+\.\d+\.\d+.\d+\.tar\.gz$/, glob ("*.tar.gz")); @@ -17,70 +150,135 @@ if (! -d "pintos") { # Sort tarballs in reverse order by time. @tarballs = sort { ext_mdyHMS ($b) cmp ext_mdyHMS ($a) } @tarballs; - - die "no pintos dir and multiple tarballs\n" if scalar (@tarballs) > 1; + + print "Multiple tarballs: choosing $tarballs[0]\n" + if scalar (@tarballs) > 1; + return $tarballs[0]; +} + +sub extract_tarball { + my ($tarball) = choose_tarball (); + mkdir "pintos" or die "pintos: mkdir: $!\n"; mkdir "pintos/src" or die "pintos: mkdir: $!\n"; - print "Extracting $tarballs[0]...\n"; - xsystem ("", "cd pintos/src && tar xzf ../../$tarballs[0]") - or die "extraction failed\n"; + print "Extracting $tarball...\n"; + xsystem ("cd pintos/src && tar xzf ../../$tarball", + DIE => "extraction failed\n"); print "Patching...\n"; - xsystem ("panic.diff", - "patch -fs pintos/src/lib/debug.c < $GRADES_DIR/panic.diff") - or die "patch failed\n"; + xsystem ("patch -fs pintos/src/lib/debug.c < $GRADES_DIR/panic.diff", + LOG => "patch", + DIE => "patch failed\n"); } --d "pintos/src/threads" or die "pintos/src/threads: stat: $!\n"; sub ext_mdyHMS { - my ($s) = $_; + my ($s) = @_; my ($ms, $d, $y, $H, $M, $S) = $s =~ /.([A-Za-z]+)\.(\d+)\.(\d+)\.(\d+)\.(\d+).(\d+)\.tar\.gz$/ or die; my ($m) = index ("janfebmaraprmayjunjulaugsepoctnovdec", lc $ms) / 3 or die; - return sprintf "%02d-%02d-%02d %02d:%02d:%02d", $m, $d, $y, $H, $M, $S; + return sprintf "%02d-%02d-%02d %02d:%02d:%02d", $y, $m, $d, $H, $M, $S; +} + +sub test_source { + my ($test) = @_; + my ($src) = "$GRADES_DIR/$test.c"; + $src = "$GRADES_DIR/mlfqs.c" if $test =~ /^mlfqs/; + -e $src or die "$src: stat: $!\n"; + return $src; } -@TESTS = ("alarm-single", "alarm-multiple", "alarm-zero", "alarm-negative", - "join-simple", - "join-quick", "join-multiple", "join-nested", - "join-dummy", "join-invalid", "join-no", - "priority-preempt", "priority-fifo", "priority-donate-one", - "priority-donate-multiple", "priority-donate-nest", - "mlfqs-on", "mlfqs-off"); +sub test_constants { + my ($defines) = ""; + $defines .= "#define MLFQS 1\n" if $test eq 'mlfqs-on'; + return $defines; + } -for $test (@TESTS) { - my ($result); - do { - print "$test: "; - $result = run_test ($test); - if ($result eq 'ok') { - $result = grade_test ($test); - $result =~ s/\n$//; - } - print "$result\n"; - } while ($result eq 'rerun'); - - $result{$test} = $result; +sub run_test { + my ($test) = @_; + + # Reuse older results if any. + if (open (DONE, "; + chomp $status; + close (DONE); + return $status; + } + + # Really run the test. + my ($status) = really_run_test ($test); + + # Save the results for later. + open (DONE, ">output/$test/done") or die "output/$test/done: create: $!\n"; + print DONE "$status\n"; + close (DONE); + + return $status; } -make_summary (); +sub really_run_test { + # Need to run it. + # If there's residue from an earlier test, move it to .old. + # If there's already a .old, delete it. + xsystem ("rm -rf output/$test.old", VERBOSE => 1) if -d "output/$test.old"; + rename "output/$test", "output/$test.old" or die "rename: $!\n" + if -d "output/$test"; + + # Make output directory. + mkdir "output/$test"; + + # Change constants.h if necessary. + my ($defines) = test_constants ($test); + if ($defines ne snarf ("pintos/src/constants.h")) { + open (CONSTANTS, ">pintos/src/constants.h"); + print CONSTANTS $defines; + close (CONSTANTS); + } + + # Copy in the new test.c and delete enough files to ensure a full rebuild. + my ($src) = test_source ($test); + xsystem ("cp $src pintos/src/threads/test.c", DIE => "cp failed\n"); + unlink ("pintos/src/threads/build/threads/test.o"); + unlink ("pintos/src/threads/build/kernel.o"); + unlink ("pintos/src/threads/build/kernel.bin"); + unlink ("pintos/src/threads/build/os.dsk"); + + # Build. + xsystem ("cd pintos/src/threads && make", LOG => "$test/make") + or return "compile error"; + + # Copy out files for backtraces later. + xsystem ("cp pintos/src/threads/build/kernel.o output/$test"); + xsystem ("cp pintos/src/threads/build/os.dsk output/$test"); + + # Run. + my ($timeout) = 10; + $timeout = 600 if $test =~ /^mlfqs/; + xsystem ("cd pintos/src/threads/build && pintos -v run -q", + LOG => "$test/run", + TIMEOUT => $timeout) + or return "Bochs error"; + + return "ok"; +} sub grade_test { my ($test) = @_; - my (@output) = snarf ("output/$test.run.out"); + my (@output) = snarf ("output/$test/run.out"); if (-e "$GRADES_DIR/$test.exp") { eval { verify_common (@output); compare_output ("$GRADES_DIR/$test.exp", @output); } - } else { + } else { + my ($grade_func); ($grade_func = $test) =~ s/-/_/g; - eval "grade_$grade_func(\@output)"; + eval "grade_$grade_func (\@output)"; } if ($@) { die $@ if $@ =~ /at \S+ line \d+$/; @@ -88,7 +286,7 @@ sub grade_test { } return "ok"; } - + sub grade_alarm_single { verify_alarm (1, @_); } @@ -97,6 +295,34 @@ sub grade_alarm_multiple { verify_alarm (7, @_); } +sub verify_alarm { + my ($iterations, @output) = @_; + + verify_common (@output); + + my (@products); + for (my ($i) = 0; $i < $iterations; $i++) { + for (my ($t) = 0; $t < 5; $t++) { + push (@products, ($i + 1) * ($t + 1) * 10); + } + } + @products = sort {$a <=> $b} @products; + + local ($_); + foreach (@output) { + die $_ if /Out of order/; + + my ($p) = /product=(\d+)$/; + next if !defined $p; + + my ($q) = shift (@products); + die "Too many wakeups.\n" if !defined $q; + die "Out of order wakeups ($p vs. $q).\n" if $p != $q; # FIXME + } + die scalar (@products) . " fewer wakeups than expected.\n" + if @products != 0; +} + sub grade_alarm_zero { my (@output) = @_; verify_common (@output); @@ -129,7 +355,8 @@ sub grade_join_multiple { verify_common (@output); my (@t); $t[4] = $t[5] = $t[6] = -1; - for $_ (@output) { + local ($_); + foreach (@output) { my ($idx) = /^Thread (\d+)/ or next; my ($iter) = /iteration (\d+)$/; $iter = 5 if /done!$/; @@ -165,7 +392,8 @@ sub grade_priority_fifo { my ($iter_cnt) = 5; my (@order); my (@t) = (-1) x $thread_cnt; - for $_ (@output) { + local ($_); + foreach (@output) { my ($idx) = /^Thread (\d+)/ or next; my ($iter) = /iteration (\d+)$/; $iter = $iter_cnt if /done!$/; @@ -198,48 +426,100 @@ sub grade_priority_fifo { sub grade_mlfqs_on { my (@output) = @_; verify_common (@output); - mlfqs_stats (@output); + our (@mlfqs_on_stats) = mlfqs_stats (@output); } sub grade_mlfqs_off { my (@output) = @_; verify_common (@output); - mlfqs_stats (@output); + our (@mlfqs_off_stats) = mlfqs_stats (@output); +} + +sub grade_mlfqs_speedup { + our (@mlfqs_off_stats); + our (@mlfqs_on_stats); + eval { + check_mlfqs (); + my ($off_ticks) = $mlfqs_off_stats[1]; + my ($on_ticks) = $mlfqs_on_stats[1]; + die "$off_ticks ticks without MLFQS, $on_ticks with MLFQS\n" + if $on_ticks >= $off_ticks; + die "ok\n"; + }; + chomp $@; + $result{'mlfqs-speedup'} = $@; +} + +sub grade_mlfqs_priority { + our (@mlfqs_off_stats); + our (@mlfqs_on_stats); + eval { + check_mlfqs () if !defined (@mlfqs_on_stats); + for my $cat qw (CPU IO MIX) { + die "Priority changed away from PRI_DEFAULT (29) without MLFQS\n" + if $mlfqs_off_stats[0]{$cat}{MIN} != 29 + || $mlfqs_off_stats[0]{$cat}{MAX} != 29; + die "Minimum priority never changed from PRI_DEFAULT (29) " + . "with MLFQS\n" + if $mlfqs_on_stats[0]{$cat}{MIN} == 29; + die "Maximum priority never changed from PRI_DEFAULT (29) " + . "with MLFQS\n" + if $mlfqs_on_stats[0]{$cat}{MAX} == 29; + } + die "ok\n"; + }; + chomp $@; + $result{'mlfqs-priority'} = $@; +} + +sub check_mlfqs { + our (@mlfqs_off_stats); + our (@mlfqs_on_stats); + die "p1-4 didn't finish with MLFQS on or off\n" + if !defined (@mlfqs_off_stats) && !defined (@mlfqs_on_stats); + die "p1-4 didn't finish with MLFQS on\n" + if !defined (@mlfqs_on_stats); + die "p1-4 didn't finish with MLFQS off\n" + if !defined (@mlfqs_off_stats); } sub mlfqs_stats { my (@output) = @_; - my (%stats) = ("io" => {}, "cpu" => {}, "mix" => {}); - my (%map) = ("CPU intensive" => "cpu", - "IO intensive" => "io", - "Alternating IO/CPU" => "mix"); - for $_ (@output) { + my (%stats) = (CPU => {}, IO => {}, MIX => {}); + my (%map) = ("CPU intensive" => 'CPU', + "IO intensive" => 'IO', + "Alternating IO/CPU" => 'MIX'); + my (%rmap) = reverse %map; + my ($ticks); + local ($_); + foreach (@output) { + $ticks = $1 if /Timer: (\d+) ticks/; my ($thread, $pri) = /^([A-Za-z\/ ]+): (\d+)$/ or next; my ($t) = $map{$thread} or next; my ($s) = $stats{$t}; - $$s{"n"}++; - $$s{"sum"} += $pri; - $$s{"sum2"} += $pri * $pri; - $$s{"min"} = $pri if !defined ($$s{"min"}) || $pri < $$s{"min"}; - $$s{"max"} = $pri if !defined ($$s{"max"}) || $pri > $$s{"max"}; - } - for my $t (keys %stats) { - my ($s) = $stats{$t}; - print "$t: n=$$s{'n'}, min=$$s{'min'}, max=$$s{'max'}, avg=", int ($$s{'sum'} / $$s{'n'}), "\n"; + $$s{N}++; + $$s{SUM} += $pri; + $$s{SUM2} += $pri * $pri; + $$s{MIN} = $pri if !defined ($$s{MIN}) || $pri < $$s{MIN}; + $$s{MAX} = $pri if !defined ($$s{MAX}) || $pri > $$s{MAX}; } -} -sub get_binaries { - if (!files_equal ("pintos/src/threads/test.c", test_source ($test)) - || !file_contains ("pintos/src/constants.h", - test_constants ($test))) { - unlink ("output/$test.run.out") - or die "output/$test.run.out: unlink: $!\n"; - die "rerun\n"; + my (%expect_n) = (CPU => 5000, IO => 1000, MIX => 12000); + for my $cat (values (%map)) { + my ($s) = $stats{$cat}; + die "$rmap{$cat} printed $$s{N} times, not $expect_n{$cat}\n" + if $$s{N} != $expect_n{$cat}; + die "$rmap{$cat} priority dropped to $$s{MIN}, below PRI_MIN (0)\n" + if $$s{MIN} < 0; + die "$rmap{$cat} priority rose to $$s{MAX}, above PRI_MAX (59)\n" + if $$s{MAX} > 59; + $$s{MEAN} = $$s{SUM} / $$s{N}; } -} + return (\%stats, $ticks); +} + sub verify_common { my (@output) = @_; @@ -249,10 +529,9 @@ sub verify_common { my (@stack_line) = grep (/Call stack:/, @output); if (@stack_line != 0) { - get_binaries (); $details .= " $stack_line[0]\n\n"; $details .= "Translation of backtrace:\n"; - my ($addrs) = $stack_line[0] =~ /Call stack:((?: 0x[0-9a-f]+)+)/; + my (@addrs) = $stack_line[0] =~ /Call stack:((?: 0x[0-9a-f]+)+)/; my ($A2L); if (`uname -m` @@ -261,8 +540,10 @@ sub verify_common { } else { $A2L = "i386-elf-addr2line"; } - open (A2L, "$A2L -fe pintos/src/threads/build/kernel.o $addrs|"); - while ($function = ) { + open (A2L, "$A2L -fe output/$test/kernel.o @addrs|"); + for (;;) { + my ($function, $line); + last unless defined ($function = ); $line = ; chomp $function; chomp $line; @@ -351,138 +632,17 @@ sub compare_output { $details{$test} = $details; die "Output differs from expected. Details at end of file.\n"; } - -sub verify_alarm { - my ($iterations, @output) = @_; - - verify_common (@output); - - my (@products); - for (my ($i) = 0; $i < $iterations; $i++) { - for (my ($t) = 0; $t < 5; $t++) { - push (@products, ($i + 1) * ($t + 1) * 10); - } - } - @products = sort {$a <=> $b} @products; - - for $_ (@output) { - die $_ if /Out of order/; - - my ($p) = /product=(\d+)$/; - next if !defined $p; - - my ($q) = shift (@products); - die "Too many wakeups.\n" if !defined $q; - die "Out of order wakeups ($p vs. $q).\n" if $p != $q; # FIXME - } - die scalar (@products) . " fewer wakeups than expected.\n" - if @products != 0; -} - -sub test_source { - my ($test) = @_; - my ($src) = "$GRADES_DIR/$test.c"; - $src = "$GRADES_DIR/mlfqs.c" if $test =~ /^mlfqs/; - -e $src or die "$src: stat: $!\n"; - return $src; -} - -sub test_constants { - my ($defines) = ""; - $defines .= "#define MLFQS 1\n" if $test eq 'mlfqs-on'; - return $defines; - } - -sub run_test { - my ($test) = @_; - return "ok" if -f "output/$test.run.out"; - - my ($defines) = test_constants ($test); - if ($defines ne snarf ("pintos/src/constants.h")) { - open (CONSTANTS, ">pintos/src/constants.h"); - print CONSTANTS $defines; - close (CONSTANTS); - } - - $src = test_source ($test); - xsystem ("", "cp $src pintos/src/threads/test.c") or die; - unlink ("pintos/src/threads/build/threads/test.o"); - unlink ("pintos/src/threads/build/kernel.o"); - unlink ("pintos/src/threads/build/kernel.bin"); - unlink ("pintos/src/threads/build/os.dsk"); - xsystem ("$test.make", "cd pintos/src/threads && make") - or return "compile error"; - - my ($timeout) = 10; - $timeout = 600 if $test =~ /^mlfqs/; - xsystem ("$test.run", "cd pintos/src/threads/build && pintos -v run -q", - $timeout) - or return "Bochs error"; - return "ok"; -} - -sub xsystem { - my ($log, $command, $timeout) = @_; - print "$command\n" if $verbose; - - $timeout = 0 if !defined $timeout; - - my ($status); - if ($log ne '') { - $status = systimeout ("($command) >output/$log.out 2>output/$log.err", - $timeout); - unlink ("output/$log.err") unless $status != 0; - } else { - $status = systimeout ($command, $timeout); - } - - die "Interrupted\n" - if WIFSIGNALED ($status) && WTERMSIG ($status) == SIGINT; - - return $status == 0; -} - -sub systimeout { - my ($command, $timeout) = @_; - my ($pid, $status); - eval { - local $SIG{ALRM} = sub { die "alarm\n" }; - alarm $timeout; - $pid = fork; - die "fork: $!\n" if !defined $pid; - exec ($command), die "$command: exec: $!\n" if !$pid; - waitpid ($pid, 0); - $status = $?; - alarm 0; - }; - if ($@) { - die unless $@ eq "alarm\n"; # propagate unexpected errors - print "Timed out.\n"; - kill SIGTERM, $pid; - $status = 0; - } - return $status; -} - -sub snarf { - my ($file) = @_; - open (OUTPUT, $file) or die "$file: open: $!\n"; - my (@lines) = ; - chomp (@lines); - close (OUTPUT); - return wantarray ? @lines : join ('', map ("$_\n", @lines)); -} - -sub make_summary { - @summary = snarf ("$GRADES_DIR/tests.txt"); + +sub write_grades { + my (@summary) = snarf ("$GRADES_DIR/tests.txt"); my ($ploss) = 0; my ($tloss) = 0; my ($total) = 0; for (my ($i) = 0; $i <= $#summary; $i++) { - $_ = $summary[$i]; + local ($_) = $summary[$i]; if (my ($loss, $test) = /^ -(\d+) ([-a-zA-Z0-9]+):/) { - my ($result) = $result{$test} or die "missing results for $test\n"; + my ($result) = $result{$test} || "Not tested."; if ($result eq 'ok') { splice (@summary, $i, 1); @@ -507,21 +667,23 @@ sub make_summary { open (SUMMARY, ">tests.out"); print SUMMARY map ("$_\n", @summary); close (SUMMARY); +} +sub write_details { open (DETAILS, ">details.out"); my ($n) = 0; for my $test (@TESTS) { next if $result{$test} eq 'ok'; my ($details) = $details{$test}; - next if !defined ($details) && ! -e "output/$test.run.out"; + next if !defined ($details) && ! -e "output/$test/run.out"; print DETAILS "\n" if $n++; print DETAILS "--- $test details ", '-' x (50 - length ($test)); print DETAILS "\n\n"; if (!defined $details) { - $details = "Output:\n\n" . snarf ("output/$test.run.out"); + $details = "Output:\n\n" . snarf ("output/$test/run.out"); } print DETAILS $details; @@ -531,6 +693,53 @@ sub make_summary { close (DETAILS); } + +sub xsystem { + my ($command, %options) = @_; + print "$command\n" if $VERBOSE || $options{VERBOSE}; + + my ($log) = $options{LOG}; + if (defined ($log)) { + $command = "($command) >output/$log.out 2>output/$log.err"; + } + + my ($pid, $status); + eval { + local $SIG{ALRM} = sub { die "alarm\n" }; + alarm $options{TIMEOUT} if defined $options{TIMEOUT}; + $pid = fork; + die "fork: $!\n" if !defined $pid; + exec ($command), die "$command: exec: $!\n" if !$pid; + waitpid ($pid, 0); + $status = $?; + alarm 0; + }; + if ($@) { + die unless $@ eq "alarm\n"; # propagate unexpected errors + print "Timed out.\n"; + kill SIGTERM, $pid; + $status = 0; + } + + if (WIFSIGNALED ($status)) { + my ($signal) = WTERMSIG ($status); + die "Interrupted\n" if $signal == SIGINT; + print "Child terminated with signal $signal\n"; + } + + unlink ("output/$log.err") if defined ($log) && $status == 0; + + return $status == 0; +} + +sub snarf { + my ($file) = @_; + open (OUTPUT, $file) or die "$file: open: $!\n"; + my (@lines) = ; + chomp (@lines); + close (OUTPUT); + return wantarray ? @lines : join ('', map ("$_\n", @lines)); +} sub files_equal { my ($a, $b) = @_;