#! /usr/bin/perl -w
use strict;
+use POSIX;
+use Fcntl;
+use File::Temp 'tempfile';
+use Getopt::Long qw(:config bundling);
+
+# Command-line options.
+our ($start_time) = time ();
+our ($sim); # Simulator: bochs, qemu, or player.
+our ($debug) = "none"; # Debugger: none, monitor, or gdb.
+our ($mem) = 4; # Physical RAM in MB.
+our ($serial) = 1; # Use serial port for input and output?
+our ($vga); # VGA output: window, terminal, or none.
+our ($jitter); # Seed for random timer interrupts, if set.
+our ($realtime); # Synchronize timer interrupts with real time?
+our ($timeout); # Maximum runtime in seconds, if set.
+our ($kill_on_failure); # Abort quickly on test failure?
+our (@puts); # Files to copy into the VM.
+our (@gets); # Files to copy out of the VM.
+our ($as_ref); # Reference to last addition to @gets or @puts.
+our (@kernel_args); # Arguments to pass to kernel.
+our (%disks) = (OS => {DEF_FN => 'os.dsk'}, # Disks to give VM.
+ FS => {DEF_FN => 'fs.dsk'},
+ SCRATCH => {DEF_FN => 'scratch.dsk'},
+ SWAP => {DEF_FN => 'swap.dsk'});
+our (@disks_by_iface) = @disks{qw (OS FS SCRATCH SWAP)};
+
+parse_command_line ();
+find_disks ();
+prepare_scratch_disk ();
+prepare_arguments ();
+run_vm ();
+finish_scratch_disk ();
-our ($mem) = 4;
-our ($serial_out) = 1;
-our (@disks) = ("os.dsk", "fs.dsk", "scratch.dsk", "swap.dsk");
-our ($sim);
-our ($debug);
-our ($vga);
-our ($jitter);
-
-use Getopt::Long qw(:config require_order bundling);
-GetOptions ("sim=s" => sub { set_sim (@_) },
- "bochs" => sub { set_sim ("bochs") },
- "qemu" => sub { set_sim ("qemu") },
- "gsx" => sub { set_sim ("gsx") },
-
- "debug=s" => sub { set_debug (@_) },
- "no-debug" => sub { set_debug ("no-debug") },
- "monitor" => sub { set_debug ("monitor") },
- "gdb" => sub { set_debug ("gdb") },
-
- "run|get|put|make-disk" => \&cmd_option,
-
- "m|memory=i" => \$mem,
- "j|jitter=i" => \$jitter,
-
- "v|no-vga" => sub { set_vga ('none'); },
- "s|no-serial" => sub { $serial_out = 0; },
- "t|terminal" => sub { set_vga ('terminal'); },
-
- "h|help" => sub { usage (0); },
-
- "0|os-disk|disk-0|hda=s" => \$disks[0],
- "1|fs-disk|disk-1|hdb=s" => \$disks[1],
- "2|scratch-disk|disk-2|hdc=s" => \$disks[2],
- "3|swap-disk|disk-3|hdd=s" => \$disks[3])
- or exit 1;
-
-$sim = "bochs" if !defined $sim;
-$debug = "no-debug" if !defined $debug;
-$vga = "window" if !defined $vga;
+exit 0;
+\f
+# Parses the command line.
+sub parse_command_line {
+ usage (0) if @ARGV == 0 || (@ARGV == 1 && $ARGV[0] eq '--help');
+
+ @kernel_args = @ARGV;
+ if (grep ($_ eq '--', @kernel_args)) {
+ @ARGV = ();
+ while ((my $arg = shift (@kernel_args)) ne '--') {
+ push (@ARGV, $arg);
+ }
+ GetOptions ("sim=s" => sub { set_sim ($_[1]) },
+ "bochs" => sub { set_sim ("bochs") },
+ "qemu" => sub { set_sim ("qemu") },
+ "player" => sub { set_sim ("player") },
+
+ "debug=s" => sub { set_debug ($_[1]) },
+ "no-debug" => sub { set_debug ("none") },
+ "monitor" => sub { set_debug ("monitor") },
+ "gdb" => sub { set_debug ("gdb") },
+
+ "m|memory=i" => \$mem,
+ "j|jitter=i" => sub { set_jitter ($_[1]) },
+ "r|realtime" => sub { set_realtime () },
+
+ "T|timeout=i" => \$timeout,
+ "k|kill-on-failure" => \$kill_on_failure,
+
+ "v|no-vga" => sub { set_vga ('none'); },
+ "s|no-serial" => sub { $serial = 0; },
+ "t|terminal" => sub { set_vga ('terminal'); },
+
+ "p|put-file=s" => sub { add_file (\@puts, $_[1]); },
+ "g|get-file=s" => sub { add_file (\@gets, $_[1]); },
+ "a|as=s" => sub { set_as ($_[1]); },
+
+ "h|help" => sub { usage (0); },
+
+ "os-disk=s" => \$disks{OS}{FILE_NAME},
+ "fs-disk=s" => \$disks{FS}{FILE_NAME},
+ "scratch-disk=s" => \$disks{SCRATCH}{FILE_NAME},
+ "swap-disk=s" => \$disks{SWAP}{FILE_NAME},
+
+ "0|disk-0|hda=s" => \$disks_by_iface[0]{FILE_NAME},
+ "1|disk-1|hdb=s" => \$disks_by_iface[1]{FILE_NAME},
+ "2|disk-2|hdc=s" => \$disks_by_iface[2]{FILE_NAME},
+ "3|disk-3|hdd=s" => \$disks_by_iface[3]{FILE_NAME})
+ or exit 1;
+ }
+
+ $sim = "bochs" if !defined $sim;
+ $debug = "none" if !defined $debug;
+ $vga = "window" if !defined $vga;
+
+ undef $timeout, print "warning: disabling timeout with --$debug\n"
+ if defined ($timeout) && $debug ne 'none';
+
+ print "warning: enabling serial port for -k or --kill-on-failure\n"
+ if $kill_on_failure && !$serial;
+}
+
+# usage($exitcode).
+# Prints a usage message and exits with $exitcode.
+sub usage {
+ my ($exitcode) = @_;
+ $exitcode = 1 unless defined $exitcode;
+ print <<'EOF';
+pintos, a utility for running Pintos in a simulator
+Usage: pintos [OPTION...] -- [ARGUMENT...]
+where each OPTION is one of the following options
+ and each ARGUMENT is passed to Pintos kernel verbatim.
+Simulator selection:
+ --bochs (default) Use Bochs as simulator
+ --qemu Use QEMU as simulator
+ --player Use VMware Player as simulator
+Debugger selection:
+ --no-debug (default) No debugger
+ --monitor Debug with simulator's monitor
+ --gdb Debug with gdb
+Display options: (default is both VGA and serial)
+ -v, --no-vga No VGA display or keyboard
+ -s, --no-serial No serial input or output
+ -t, --terminal Display VGA in terminal (Bochs only)
+Timing options: (Bochs only)
+ -j SEED Randomize timer interrupts
+ -r, --realtime Use realistic, not reproducible, timings
+Testing options:
+ -T, --timeout=N Kill Pintos after N seconds CPU time or N*load_avg
+ seconds wall-clock time (whichever comes first)
+ -k, --kill-on-failure Kill Pintos a few seconds after a kernel or user
+ panic, test failure, or triple fault
+Configuration options:
+ -m, --mem=N Give Pintos N MB physical RAM (default: 4)
+File system commands (for `run' command):
+ -p, --put-file=HOSTFN Copy HOSTFN into VM, by default under same name
+ -g, --get-file=GUESTFN Copy GUESTFN out of VM, by default under same name
+ -a, --as=FILENAME Specifies guest (for -p) or host (for -g) file name
+Disk options: (name an existing FILE or specify SIZE in MB for a temp disk)
+ --os-disk=FILE Set OS disk file (default: os.dsk)
+ --fs-disk=FILE|SIZE Set FS disk file (default: fs.dsk)
+ --scratch-disk=FILE|SIZE Set scratch disk (default: scratch.dsk)
+ --swap-disk=FILE|SIZE Set swap disk file (default: swap.dsk)
+Other options:
+ -h, --help Display this help message.
+EOF
+ exit $exitcode;
+}
+# Sets the simulator.
sub set_sim {
my ($new_sim) = @_;
die "--$new_sim conflicts with --$sim\n"
$sim = $new_sim;
}
+# Sets the debugger.
sub set_debug {
my ($new_debug) = @_;
die "--$new_debug conflicts with --$debug\n"
- if defined ($debug) && $debug ne $new_debug;
+ if $debug ne 'none' && $new_debug ne 'none' && $debug ne $new_debug;
$debug = $new_debug;
}
+# Sets VGA output destination.
sub set_vga {
my ($new_vga) = @_;
if (defined ($vga) && $vga ne $new_vga) {
$vga = $new_vga;
}
-sub cmd_option {
- # Force an end to option processing, as with --.
- die ("!FINISH");
-}
-
-die "no command specified; use --help for help\n"
- if @ARGV < 1;
-my ($cmd) = shift @ARGV;
-if ($cmd eq 'run') {
- run_vm (@ARGV);
-} elsif ($cmd eq 'make-disk') {
- usage () if @ARGV != 2;
- my ($file, $mb) = @ARGV;
- usage () if $mb !~ /^\d+(\.\d+)?|\.\d+$/;
- die "$file: already exists\n" if -e $file;
-
- create_disk ($file, int ($mb * 1008));
-} elsif ($cmd eq 'put') {
- # Take a -f option to combine formatting with putting.
- my ($format) = 0;
- if (@ARGV > 0 && $ARGV[0] eq '-f') {
- shift @ARGV;
- $format = 1;
- }
-
- usage () if @ARGV != 1 && @ARGV != 2;
- my ($hostfn, $guestfn) = @ARGV;
- $guestfn = $hostfn if !defined $guestfn;
-
- # Create scratch disk from file.
- die "$hostfn: $!\n" if ! -e $hostfn;
- my ($size) = -s _;
- copy_pad ($hostfn, "scratch.dsk", 512);
-
- # Do copy.
- my (@cmd) = ("-ci", $guestfn, $size, "-q");
- unshift (@cmd, "-f") if $format;
- run_vm (@cmd);
-} elsif ($cmd eq 'get') {
- usage () if @ARGV != 1 && @ARGV != 2;
- my ($guestfn, $hostfn) = @ARGV;
- $hostfn = $guestfn if !defined $hostfn;
- die "$hostfn: already exists\n" if -e $hostfn;
-
- # Create scratch disk big enough for any file in the filesystem
- # (modulo sparse files).
- die "$disks[1]: $!\n" if ! -e $disks[1];
- my ($fs_size) = -s _;
- my ($scratch_size) = -s $disks[2];
- $scratch_size = 0 if !defined $scratch_size;
- create_disk ($disks[2], $fs_size / 1024 + 16)
- if $scratch_size < $fs_size + 16384;
-
- # Do copy.
- run_vm ("-co", $guestfn, "-q");
-
- # Read out scratch disk.
- print "copying $guestfn from $disks[2] to $hostfn...\n";
- open (SRC, "<$disks[2]") or die "$disks[2]: open: $!\n";
- open (DST, ">$hostfn") or die "$hostfn: create: $!\n";
- my ($input);
- read (SRC, $input, 512) == 512 or die "$disks[2]: read error\n";
- my ($size) = unpack ("V", $input);
- $size != 0xffffffff or die "$guestfn: too big for $disks[2]?";
- my ($src);
- read (SRC, $src, $size) == $size or die "$disks[2]: read error\n";
- print DST $src or die "$hostfn: write error\n";
- close (DST);
- close (SRC);
-} elsif ($cmd eq 'help') {
- usage (0);
-} else {
- die "unknown command `$cmd'; use --help for help\n";
+# Sets randomized timer interrupts.
+sub set_jitter {
+ my ($new_jitter) = @_;
+ die "--realtime conflicts with --jitter\n" if defined $realtime;
+ die "different --jitter already defined\n"
+ if defined $jitter && $jitter != $new_jitter;
+ $jitter = $new_jitter;
}
-exit 0;
-sub usage {
- my ($exitcode) = @_;
- $exitcode = 1 unless defined $exitcode;
- print "pintos, a utility for invoking Pintos in a simulator\n";
- print "Usage: pintos [OPTION...] COMMAND [ARG...]\n";
- print "where COMMAND is one of the following:\n";
- print " run [CMDLINE...] run a VM in the simulator\n";
- print " make-disk FILE.DSK SIZE create FILE.DSK as empty SIZE MB disk\n";
- print " put HOSTFN [GUESTFN] copy HOSTFN into VM (as GUESTFN)\n";
- print " get GUESTFN [HOSTFN] copy GUESTFN out of VM (to HOSTFN)\n";
- print " help print this help message and exit\n";
- print "Simulator options:\n";
- print " --bochs (default) Use Bochs as simulator\n";
- print " --qemu Use qemu as simulator\n";
- print " --gsx Use VMware GSX Server 3.x as simulator\n";
- print "Debugger options:\n";
- print " --no-debug (default) No debugger\n";
- print " --monitor Debug with simulator's monitor\n";
- print " --gdb Debug with gdb\n";
- print "Display options: (default is VGA + serial)\n";
- print " -v, --no-vga No VGA display\n";
- print " -s, --no-serial No serial output\n";
- print " -t, --terminal Display VGA in terminal (Bochs only)\n";
- print "VM options:\n";
- print " -j SEED Randomize timer interrupts (Bochs only)\n";
- print " -m, --mem=MB Run VM with MB megabytes of physical memory\n";
- print "Disk options:\n";
- print " --os-disk=DISK Set OS disk file (default: os.dsk)\n";
- print " --fs-disk=DISK Set FS disk file (default: fs.dsk)\n";
- print " --scratch-disk=DISK Set scratch disk (default: scratch.dsk)\n";
- print " --swap-disk=DISK Set swap disk file (default: swap.dsk)\n";
- exit $exitcode;
+# Sets real-time timer interrupts.
+sub set_realtime {
+ die "--realtime conflicts with --jitter\n" if defined $jitter;
+ $realtime = 1;
}
-sub copy_pad {
- my ($src, $dst, $blocksize) = @_;
- run_command ("dd", "if=$src", "of=$dst", "bs=$blocksize", "conv=sync");
+# add_file(\@list, $file)
+#
+# Adds [$file] to @list, which should be @puts or @gets.
+# Sets $as_ref to point to the added element.
+sub add_file {
+ my ($list, $file) = @_;
+ $as_ref = [$file];
+ push (@$list, $as_ref);
}
-sub create_disk {
- my ($disk, $kb) = @_;
- run_command ("dd", "if=/dev/zero", "of=$disk", "bs=1024", "count=$kb");
+# Sets the guest/host name for the previous put/get.
+sub set_as {
+ my ($as) = @_;
+ die "-a (or --as) is only allowed after -p or -g\n" if !defined $as_ref;
+ die "Only one -a (or --as) is allowed after -p or -g\n"
+ if defined $as_ref->[1];
+ $as_ref->[1] = $as;
}
+\f
+# Locates the files used to back each of the virtual disks,
+# and creates temporary disks.
+sub find_disks {
+ for my $disk (values %disks) {
+ # If there's no assigned file name but the default file exists,
+ # try to assign a default file name.
+ if (!defined ($disk->{FILE_NAME})) {
+ for my $try_fn ($disk->{DEF_FN}, "build/" . $disk->{DEF_FN}) {
+ $disk->{FILE_NAME} = $try_fn, last
+ if -e $try_fn;
+ }
+ }
-sub run_vm {
- our (@disks);
-
- die "$disks[0]: can't find OS disk\n" if ! -e $disks[0];
- for my $i (1...3) {
- undef $disks[$i] if ! -e $disks[$i];
- }
+ # If there's no file name, we're done.
+ next if !defined ($disk->{FILE_NAME});
- write_cmd_line ($disks[0], @_);
+ if ($disk->{FILE_NAME} =~ /^\d+(\.\d+)?|\.\d+$/) {
+ # Create a temporary disk of approximately the specified
+ # size in megabytes.
+ die "OS disk can't be temporary\n" if $disk == $disks{OS};
- if ($sim eq 'bochs') {
- my ($bin);
- if ($debug eq 'no-debug') {
- $bin = 'bochs';
- } elsif ($debug eq 'monitor') {
- $bin = 'bochs-dbg';
- } elsif ($debug eq 'gdb') {
- $bin = 'bochs-gdb';
- }
+ my ($mb) = $disk->{FILE_NAME};
+ undef $disk->{FILE_NAME};
- my ($bochsbin) = search_path ($bin);
- my ($bochsshare) = "$bochsbin/../share/bochs";
-
- open (BOCHSRC, ">bochsrc.txt") or die "bochsrc.txt: create: $!\n";
- print BOCHSRC "romimage: file=$bochsshare/BIOS-bochs-latest, "
- . "address=0xf0000\n";
- print BOCHSRC "vgaromimage: $bochsshare/VGABIOS-lgpl-latest\n";
- print BOCHSRC bochs_disk_line ("ata0-master", $disks[0]);
- print BOCHSRC bochs_disk_line ("ata0-slave", $disks[1]);
- print BOCHSRC "ata1: enabled=1, ioaddr1=0x170, ioaddr2=0x370, irq=15\n"
- if defined ($disks[2]) || defined ($disks[3]);
- print BOCHSRC bochs_disk_line ("ata1-master", $disks[2]);
- print BOCHSRC bochs_disk_line ("ata1-slave", $disks[3]);
- print BOCHSRC "boot: c\n";
- print BOCHSRC "ips: 1000000\n";
- print BOCHSRC "clock: sync=none, time0=0\n";
- print BOCHSRC "megs: $mem\n";
- print BOCHSRC "log: bochsout.txt\n";
- if ($vga ne 'terminal') {
- print BOCHSRC "com1: enabled=1, dev=/dev/stdout\n"
- if $serial_out;
- print BOCHSRC "display_library: nogui\n"
- if $vga eq 'none';
+ my ($cyl_size) = 512 * 16 * 63;
+ extend_disk ($disk, ceil ($mb * 2) * $cyl_size);
} else {
- print BOCHSRC "display_library: term\n";
+ # The file must exist and have nonzero size.
+ -e $disk->{FILE_NAME} or die "$disk->{FILE_NAME}: stat: $!\n";
+ -s _ or die "$disk->{FILE_NAME}: disk has zero size\n";
}
- close (BOCHSRC);
+ }
- my (@cmd) = ($bin, '-q');
- push (@cmd, '-j', $jitter) if defined $jitter;
- run_command_no_die (@cmd);
- } elsif ($sim eq 'qemu') {
- print "warning: qemu doesn't support --terminal\n"
- if $vga eq 'terminal';
- print "warning: qemu doesn't support jitter\n"
- if defined $jitter;
- my (@cmd) = ('qemu');
- push (@cmd, '-hda', $disks[0]) if defined $disks[0];
- push (@cmd, '-hdb', $disks[1]) if defined $disks[1];
- push (@cmd, '-hdc', $disks[2]) if defined $disks[2];
- push (@cmd, '-hdd', $disks[3]) if defined $disks[3];
- push (@cmd, '-m', $mem);
- push (@cmd, '-nographic') if $vga eq 'none';
- push (@cmd, '-serial', 'stdio') if $serial_out && $vga ne 'none';
- push (@cmd, '-S') if $debug eq 'monitor';
- push (@cmd, '-s') if $debug eq 'gdb';
- run_command (@cmd);
- } elsif ($sim eq 'gsx') {
- print "warning: VMware GSX Server doesn't support --$debug\n"
- if $debug ne 'no-debug';
- print "warning: VMware GSX Server doesn't support --no-vga\n"
- if $vga eq 'none';
- print "warning: VMware GSX Server doesn't support --terminal\n"
- if $vga eq 'terminal';
- print "warning: VMware GSX Server doesn't support jitter\n"
- if defined $jitter;
-
- open (VMX, ">pintos.vmx") or die "pintos.vmx: create: $!\n";
- chmod 0777 & ~umask, "pintos.vmx";
- print VMX "#! /usr/bin/vmware -G\n";
- print VMX "config.version = 6\n";
- print VMX "guestOS = \"linux\"\n";
- print VMX "floppy0.present = FALSE\n";
-
- if (! -e 'null.bin') {
- open (NULL, ">null.bin") or die "null.bin: create: $!\n";
- close (NULL);
+ # Warn about (potentially) missing disks.
+ die "Cannot find OS disk\n" if !defined $disks{OS}{FILE_NAME};
+ if (my ($project) = `pwd` =~ /\b(threads|userprog|vm|filesys)\b/) {
+ if ((grep ($project eq $_, qw (userprog vm filesys)))
+ && !defined ($disks{FS}{FILE_NAME})) {
+ print STDERR "warning: it looks like you're running the $project ";
+ print STDERR "project, but no file system disk is present\n";
+ }
+ if ($project eq 'vm' && !defined $disks{SWAP}{FILE_NAME}) {
+ print STDERR "warning: it looks like you're running the $project ";
+ print STDERR "project, but no swap disk is present\n";
}
+ }
+}
+\f
+# Prepare the scratch disk for gets and puts.
+sub prepare_scratch_disk {
+ if (@puts) {
+ # Write ustar header and data for each file.
+ put_scratch_file ($_->[0],
+ defined $_->[1] ? $_->[1] : $_->[0])
+ foreach @puts;
+
+ # Write end-of-archive marker.
+ write_fully ($disks{SCRATCH}{HANDLE}, $disks{SCRATCH}{FILE_NAME},
+ "\0" x 1024);
+ }
+
+ # Make sure the scratch disk is big enough to get big files.
+ extend_disk ($disks{SCRATCH}, @gets * 1024 * 1024) if @gets;
+}
+
+# Read "get" files from the scratch disk.
+sub finish_scratch_disk {
+ # We need to start reading the scratch disk from the beginning again.
+ if (@gets) {
+ close ($disks{SCRATCH}{HANDLE});
+ undef ($disks{SCRATCH}{HANDLE});
+ }
- for (my ($i) = 0; $i < 4; $i++) {
- my ($dsk) = $disks[$i];
- next if !defined $dsk;
-
- my ($pln) = $dsk;
- $pln =~ s/\.dsk//;
- $pln .= ".pln";
-
- my ($device) = "ide" . int ($i / 2) . ":" . ($i % 2);
- print VMX "\n$device.present = TRUE\n";
- print VMX "$device.deviceType = \"plainDisk\"\n";
- print VMX "$device.fileName = \"$pln\"\n";
-
- my (%geom) = disk_geometry ($dsk);
- open (PLN, ">$pln") or die "$pln: create: $!\n";
- print PLN "DRIVETYPE ide\n";
- print PLN "#vm|VERSION 2\n";
- print PLN "#vm|TOOLSVERSION 2\n";
- print PLN "CYLINDERS $geom{C}\n";
- print PLN "HEADS $geom{H}\n";
- print PLN "SECTORS $geom{S}\n";
- print PLN "#vm|CAPACITY $geom{CAPACITY}\n";
- print PLN "ACCESS \"$dsk\" 0 $geom{CAPACITY}\n";
- close (PLN);
+ # Read each file.
+ # If reading fails, delete that file and all subsequent files.
+ my ($ok) = 1;
+ foreach my $get (@gets) {
+ my ($name) = defined ($get->[1]) ? $get->[1] : $get->[0];
+ my ($error) = get_scratch_file ($name);
+ if ($error) {
+ print STDERR "getting $name failed ($error)\n";
+ die "$name: unlink: $!\n" if !unlink ($name) && !$!{ENOENT};
+ $ok = 0;
}
- close (VMX);
-
- use Cwd;
- my ($vmx) = getcwd () . "/pintos.vmx";
- system ("vmware-cmd -s register $vmx >&/dev/null");
- system ("vmware-cmd $vmx stop hard >&/dev/null");
- system ("vmware -l -G -x -q $vmx");
- system ("vmware-cmd $vmx stop hard >&/dev/null");
}
}
+# mk_ustar_field($number, $size)
+#
+# Returns $number in a $size-byte numeric field in the format used by
+# the standard ustar archive header.
+sub mk_ustar_field {
+ my ($number, $size) = @_;
+ my ($len) = $size - 1;
+ my ($out) = sprintf ("%0${len}o", $number) . "\0";
+ die "$number: too large for $size-byte octal ustar field\n"
+ if length ($out) != $size;
+ return $out;
+}
+
+# calc_ustar_chksum($s)
+#
+# Calculates and returns the ustar checksum of 512-byte ustar archive
+# header $s.
+sub calc_ustar_chksum {
+ my ($s) = @_;
+ die if length ($s) != 512;
+ substr ($s, 148, 8, ' ' x 8);
+ return unpack ("%32a*", $s);
+}
+
+# put_scratch_file($src_file_name, $dst_file_name).
+#
+# Copies $src_file_name into the scratch disk for extraction as
+# $dst_file_name.
+sub put_scratch_file {
+ my ($src_file_name, $dst_file_name) = @_;
+ my ($disk_handle, $disk_file_name) = open_disk ($disks{SCRATCH});
+
+ print "Copying $src_file_name to scratch partition...\n";
+
+ # ustar format supports up to 100 characters for a file name, and
+ # even longer names given some common properties, but our code in
+ # the Pintos kernel only supports at most 99 characters.
+ die "$dst_file_name: name too long (max 99 characters)\n"
+ if length ($dst_file_name) > 99;
+
+ # Compose and write ustar header.
+ stat $src_file_name or die "$src_file_name: stat: $!\n";
+ my ($size) = -s _;
+ my ($header) = (pack ("a100", $dst_file_name) # name
+ . mk_ustar_field (0644, 8) # mode
+ . mk_ustar_field (0, 8) # uid
+ . mk_ustar_field (0, 8) # gid
+ . mk_ustar_field ($size, 12) # size
+ . mk_ustar_field (1136102400, 12) # mtime
+ . (' ' x 8) # chksum
+ . '0' # typeflag
+ . ("\0" x 100) # linkname
+ . "ustar\0" # magic
+ . "00" # version
+ . "root" . ("\0" x 28) # uname
+ . "root" . ("\0" x 28) # gname
+ . "\0" x 8 # devmajor
+ . "\0" x 8 # devminor
+ . ("\0" x 155)) # prefix
+ . "\0" x 12; # pad to 512 bytes
+ substr ($header, 148, 8) = mk_ustar_field (calc_ustar_chksum ($header), 8);
+ write_fully ($disk_handle, $disk_file_name, $header);
+
+ # Copy file data.
+ my ($put_handle);
+ sysopen ($put_handle, $src_file_name, O_RDONLY)
+ or die "$src_file_name: open: $!\n";
+ copy_file ($put_handle, $src_file_name, $disk_handle, $disk_file_name,
+ $size);
+ die "$src_file_name: changed size while being read\n"
+ if $size != -s $put_handle;
+ close ($put_handle);
+
+ # Round up disk data to beginning of next sector.
+ write_fully ($disk_handle, $disk_file_name, "\0" x (512 - $size % 512))
+ if $size % 512;
+}
+
+# get_scratch_file($file).
+#
+# Copies from the scratch disk to $file.
+# Returns 1 if successful, 0 on failure.
+sub get_scratch_file {
+ my ($get_file_name) = @_;
+ my ($disk_handle, $disk_file_name) = open_disk ($disks{SCRATCH});
+
+ print "Copying $get_file_name out of $disk_file_name...\n";
+
+ # Read ustar header sector.
+ my ($header) = read_fully ($disk_handle, $disk_file_name, 512);
+ return "scratch disk tar archive ends unexpectedly"
+ if $header eq ("\0" x 512);
+
+ # Verify magic numbers.
+ return "corrupt ustar signature" if substr ($header, 257, 6) ne "ustar\0";
+ return "invalid ustar version" if substr ($header, 263, 2) ne '00';
+
+ # Verify checksum.
+ my ($chksum) = oct (unpack ("Z*", substr ($header, 148, 8)));
+ my ($correct_chksum) = calc_ustar_chksum ($header);
+ return "checksum mismatch" if $chksum != $correct_chksum;
+
+ # Get type.
+ my ($typeflag) = substr ($header, 156, 1);
+ return "not a regular file" if $typeflag ne '0' && $typeflag ne "\0";
+
+ # Get size.
+ my ($size) = oct (unpack ("Z*", substr ($header, 124, 12)));
+ return "bad size $size\n" if $size < 0;
+
+ # Copy file data.
+ my ($get_handle);
+ sysopen ($get_handle, $get_file_name, O_WRONLY | O_CREAT, 0666)
+ or die "$get_file_name: create: $!\n";
+ copy_file ($disk_handle, $disk_file_name, $get_handle, $get_file_name,
+ $size);
+ close ($get_handle);
+
+ # Skip forward in disk up to beginning of next sector.
+ read_fully ($disk_handle, $disk_file_name, 512 - $size % 512)
+ if $size % 512;
+
+ return 0;
+}
+\f
+# Prepares the arguments to pass to the Pintos kernel,
+# and then write them into Pintos bootloader.
+sub prepare_arguments {
+ my (@args);
+ push (@args, shift (@kernel_args))
+ while @kernel_args && $kernel_args[0] =~ /^-/;
+ push (@args, 'extract') if @puts;
+ push (@args, @kernel_args);
+ push (@args, 'append', $_->[0]) foreach @gets;
+ write_cmd_line ($disks{OS}, @args);
+}
+
+# Writes @args into the Pintos bootloader at the beginning of $disk.
sub write_cmd_line {
my ($disk, @args) = @_;
- die "command line includes empty string" if grep (/^$/, @args);
- my ($args) = join ("\0", @args) . "\0\0";
+ # Figure out command line to write.
+ my ($arg_cnt) = pack ("V", scalar (@args));
+ my ($args) = join ('', map ("$_\0", @args));
die "command line exceeds 128 bytes" if length ($args) > 128;
$args .= "\0" x (128 - length ($args));
- print "writing command line to $disk...\n";
- open (DISK, "+<$disk") or die "$disk: open: $!\n";
- seek (DISK, 0x17e, 0) or die "$disk: seek: $!\n";
- syswrite (DISK, $args) or die "$disk: write: $!\n";
- close (DISK) or die "$disk: close: $!\n";
+ # Write command line.
+ my ($handle, $file_name) = open_disk_copy ($disk);
+ print "Writing command line to $file_name...\n";
+ sysseek ($handle, 0x17a, 0) == 0x17a or die "$file_name: seek: $!\n";
+ syswrite ($handle, "$arg_cnt$args") or die "$file_name: write: $!\n";
}
+\f
+# Running simulators.
-sub run_command {
- print join (' ', @_), "\n";
- die "command failed\n" if system (@_);
+# Runs the selected simulator.
+sub run_vm {
+ if ($sim eq 'bochs') {
+ run_bochs ();
+ } elsif ($sim eq 'qemu') {
+ run_qemu ();
+ } elsif ($sim eq 'player') {
+ run_player ();
+ } else {
+ die "unknown simulator `$sim'\n";
+ }
}
-sub run_command_no_die {
- print join (' ', @_), "\n";
- system (@_);
+# Runs Bochs.
+sub run_bochs {
+ # Select Bochs binary based on the chosen debugger.
+ my ($bin) = $debug eq 'monitor' ? 'bochs-dbg' : 'bochs';
+
+ my ($squish_pty);
+ if ($serial) {
+ $squish_pty = find_in_path ("squish-pty");
+ print "warning: can't find squish-pty, so terminal input will fail\n"
+ if !defined $squish_pty;
+ }
+
+ # Write bochsrc.txt configuration file.
+ open (BOCHSRC, ">", "bochsrc.txt") or die "bochsrc.txt: create: $!\n";
+ print BOCHSRC <<EOF;
+romimage: file=\$BXSHARE/BIOS-bochs-latest
+vgaromimage: file=\$BXSHARE/VGABIOS-lgpl-latest
+boot: disk
+cpu: ips=1000000
+megs: $mem
+log: bochsout.txt
+panic: action=fatal
+EOF
+ print BOCHSRC "gdbstub: enabled=1\n" if $debug eq 'gdb';
+ if ($realtime) {
+ print BOCHSRC "clock: sync=realtime\n";
+ } else {
+ print BOCHSRC "clock: sync=none, time0=0\n";
+ }
+ print_bochs_disk_line ("ata0-master", 0);
+ print_bochs_disk_line ("ata0-slave", 1);
+ if (defined ($disks_by_iface[2]{FILE_NAME})
+ || defined ($disks_by_iface[3]{FILE_NAME})) {
+ print BOCHSRC "ata1: enabled=1, ioaddr1=0x170, ",
+ "ioaddr2=0x370, irq=15\n";
+ print_bochs_disk_line ("ata1-master", 2);
+ print_bochs_disk_line ("ata1-slave", 3);
+ }
+ if ($vga ne 'terminal') {
+ if ($serial) {
+ my $mode = defined ($squish_pty) ? "term" : "file";
+ print BOCHSRC "com1: enabled=1, mode=$mode, dev=/dev/stdout\n";
+ }
+ print BOCHSRC "display_library: nogui\n" if $vga eq 'none';
+ } else {
+ print BOCHSRC "display_library: term\n";
+ }
+ close (BOCHSRC);
+
+ # Compose Bochs command line.
+ my (@cmd) = ($bin, '-q');
+ unshift (@cmd, $squish_pty) if defined $squish_pty;
+ push (@cmd, '-j', $jitter) if defined $jitter;
+
+ # Run Bochs.
+ print join (' ', @cmd), "\n";
+ my ($exit) = xsystem (@cmd);
+ if (WIFEXITED ($exit)) {
+ # Bochs exited normally.
+ # Ignore the exit code; Bochs normally exits with status 1,
+ # which is weird.
+ } elsif (WIFSIGNALED ($exit)) {
+ die "Bochs died with signal ", WTERMSIG ($exit), "\n";
+ } else {
+ die "Bochs died: code $exit\n";
+ }
+}
+
+# print_bochs_disk_line($device, $iface)
+#
+# If IDE interface $iface has a disk attached, prints a bochsrc.txt
+# line for attaching it to $device.
+sub print_bochs_disk_line {
+ my ($device, $iface) = @_;
+ my ($disk) = $disks_by_iface[$iface];
+ my ($file) = $disk->{FILE_NAME};
+ if (defined $file) {
+ my (%geom) = disk_geometry ($disk);
+ print BOCHSRC "$device: type=disk, path=$file, mode=flat, ";
+ print BOCHSRC "cylinders=$geom{C}, heads=$geom{H}, spt=$geom{S}, ";
+ print BOCHSRC "translation=none\n";
+ }
}
-sub search_path {
- my ($target) = @_;
- for my $dir (split (':', $ENV{PATH})) {
- return $dir if -e "$dir/$target";
+# Runs QEMU.
+sub run_qemu {
+ print "warning: qemu doesn't support --terminal\n"
+ if $vga eq 'terminal';
+ print "warning: qemu doesn't support jitter\n"
+ if defined $jitter;
+ my (@cmd) = ('qemu');
+ for my $iface (0...3) {
+ my ($option) = ('-hda', '-hdb', '-hdc', '-hdd')[$iface];
+ push (@cmd, $option, $disks_by_iface[$iface]{FILE_NAME})
+ if defined $disks_by_iface[$iface]{FILE_NAME};
+ }
+ push (@cmd, '-m', $mem);
+ push (@cmd, '-net', 'none');
+ push (@cmd, '-nographic') if $vga eq 'none';
+ push (@cmd, '-serial', 'stdio') if $serial && $vga ne 'none';
+ push (@cmd, '-S') if $debug eq 'monitor';
+ push (@cmd, '-s', '-S') if $debug eq 'gdb';
+ push (@cmd, '-monitor', 'null') if $vga eq 'none' && $debug eq 'none';
+ run_command (@cmd);
+}
+
+# player_unsup($flag)
+#
+# Prints a message that $flag is unsupported by VMware Player.
+sub player_unsup {
+ my ($flag) = @_;
+ print "warning: no support for $flag with VMware Player\n";
+}
+
+# Runs VMware Player.
+sub run_player {
+ player_unsup ("--$debug") if $debug ne 'none';
+ player_unsup ("--no-vga") if $vga eq 'none';
+ player_unsup ("--terminal") if $vga eq 'terminal';
+ player_unsup ("--jitter") if defined $jitter;
+ player_unsup ("--timeout"), undef $timeout if defined $timeout;
+ player_unsup ("--kill-on-failure"), undef $kill_on_failure
+ if defined $kill_on_failure;
+
+ # Memory size must be multiple of 4.
+ $mem = int (($mem + 3) / 4) * 4;
+
+ open (VMX, ">", "pintos.vmx") or die "pintos.vmx: create: $!\n";
+ chmod 0777 & ~umask, "pintos.vmx";
+ print VMX <<EOF;
+#! /usr/bin/vmware -G
+config.version = 8
+guestOS = "linux"
+memsize = $mem
+floppy0.present = FALSE
+usb.present = FALSE
+sound.present = FALSE
+gui.exitAtPowerOff = TRUE
+gui.exitOnCLIHLT = TRUE
+gui.powerOnAtStartUp = TRUE
+EOF
+
+
+
+ print VMX <<EOF if $serial;
+serial0.present = TRUE
+serial0.fileType = "pipe"
+serial0.fileName = "pintos.socket"
+serial0.pipe.endPoint = "client"
+serial0.tryNoRxLoss = "TRUE"
+EOF
+
+ for (my ($i) = 0; $i < 4; $i++) {
+ my ($disk) = $disks_by_iface[$i];
+ my ($dsk) = $disk->{FILE_NAME};
+ next if !defined $dsk;
+
+ my ($device) = "ide" . int ($i / 2) . ":" . ($i % 2);
+ my ($pln) = "$device.pln";
+ print VMX <<EOF;
+
+$device.present = TRUE
+$device.deviceType = "plainDisk"
+$device.fileName = "$pln"
+EOF
+
+ open (URANDOM, '<', '/dev/urandom') or die "/dev/urandom: open: $!\n";
+ my ($bytes);
+ sysread (URANDOM, $bytes, 4) == 4 or die "/dev/urandom: read: $!\n";
+ close (URANDOM);
+ my ($cid) = unpack ("L", $bytes);
+
+ my (%geom) = disk_geometry ($disk);
+ open (PLN, ">", $pln) or die "$pln: create: $!\n";
+ print PLN <<EOF;
+version=1
+CID=$cid
+parentCID=ffffffff
+createType="monolithicFlat"
+
+RW $geom{CAPACITY} FLAT "$dsk" 0
+
+# The Disk Data Base
+#DDB
+
+ddb.adapterType = "ide"
+ddb.virtualHWVersion = "4"
+ddb.toolsVersion = "2"
+ddb.geometry.cylinders = "$geom{C}"
+ddb.geometry.heads = "$geom{H}"
+ddb.geometry.sectors = "$geom{S}"
+EOF
+ close (PLN);
+ }
+ close (VMX);
+
+ my ($squish_unix);
+ if ($serial) {
+ $squish_unix = find_in_path ("squish-unix");
+ print "warning: can't find squish-unix, so terminal input ",
+ "and output will fail\n" if !defined $squish_unix;
+ }
+
+ my ($vmx) = getcwd () . "/pintos.vmx";
+ my (@cmd) = ("vmplayer", $vmx);
+ unshift (@cmd, $squish_unix, "pintos.socket") if $squish_unix;
+ print join (' ', @cmd), "\n";
+ xsystem (@cmd);
+}
+\f
+# Disk utilities.
+
+# open_disk($disk)
+#
+# Opens $disk, if it is not already open, and returns its file handle
+# and file name.
+sub open_disk {
+ my ($disk) = @_;
+ if (!defined ($disk->{HANDLE})) {
+ if ($disk->{FILE_NAME}) {
+ sysopen ($disk->{HANDLE}, $disk->{FILE_NAME}, O_RDWR)
+ or die "$disk->{FILE_NAME}: open: $!\n";
+ } else {
+ ($disk->{HANDLE}, $disk->{FILE_NAME}) = tempfile (UNLINK => 1,
+ SUFFIX => '.dsk');
+ }
}
- die "$target not in PATH\n";
+ return ($disk->{HANDLE}, $disk->{FILE_NAME});
}
-sub bochs_disk_line {
- my ($device, $file) = @_;
- return "" if !defined $file;
- my (%geom) = disk_geometry ($file);
- return "$device: type=disk, path=$file, mode=flat, "
- . "cylinders=$geom{C}, heads=$geom{H}, spt=$geom{S}, "
- . "translation=none\n";
+# open_disk_copy($disk)
+#
+# Makes a temporary copy of $disk and returns its file handle and file name.
+sub open_disk_copy {
+ my ($disk) = @_;
+ die if !$disk->{FILE_NAME};
+
+ my ($orig_handle, $orig_file_name) = open_disk ($disk);
+ my ($cp_handle, $cp_file_name) = tempfile (UNLINK => 1, SUFFIX => '.dsk');
+ copy_file ($orig_handle, $orig_file_name, $cp_handle, $cp_file_name,
+ -s $orig_handle);
+ return ($disk->{HANDLE}, $disk->{FILE_NAME}) = ($cp_handle, $cp_file_name);
}
+# extend_disk($disk, $size)
+#
+# Extends $disk, if necessary, so that it is at least $size bytes
+# long.
+sub extend_disk {
+ my ($disk, $size) = @_;
+ my ($handle, $file_name) = open_disk ($disk);
+ if (-s ($handle) < $size) {
+ sysseek ($handle, $size - 1, 0) == $size - 1
+ or die "$file_name: seek: $!\n";
+ syswrite ($handle, "\0") == 1
+ or die "$file_name: write: $!\n";
+ }
+}
+
+# disk_geometry($file)
+#
+# Examines $file and returns a valid IDE disk geometry for it, as a
+# hash.
sub disk_geometry {
- my ($file) = @_;
+ my ($disk) = @_;
+ my ($file) = $disk->{FILE_NAME};
my ($size) = -s $file;
die "$file: stat: $!\n" if !defined $size;
die "$file: size not a multiple of 512 bytes\n" if $size % 512;
- my ($cylinders) = int ($size / (512 * 16 * 63));
- $cylinders++ if $size % (512 * 16 * 63);
+ my ($cyl_size) = 512 * 16 * 63;
+ my ($cylinders) = ceil ($size / $cyl_size);
+ extend_disk ($disk, $cylinders * $cyl_size) if $size % $cyl_size;
return (CAPACITY => $size / 512,
C => $cylinders,
H => 16,
S => 63);
}
+
+# copy_file($from_handle, $from_file_name, $to_handle, $to_file_name, $size)
+#
+# Copies $size bytes from $from_handle to $to_handle.
+# $from_file_name and $to_file_name are used in error messages.
+sub copy_file {
+ my ($from_handle, $from_file_name, $to_handle, $to_file_name, $size) = @_;
+
+ while ($size > 0) {
+ my ($chunk_size) = 4096;
+ $chunk_size = $size if $chunk_size > $size;
+ $size -= $chunk_size;
+
+ my ($data) = read_fully ($from_handle, $from_file_name, $chunk_size);
+ write_fully ($to_handle, $to_file_name, $data);
+ }
+}
+
+# read_fully($handle, $file_name, $bytes)
+#
+# Reads exactly $bytes bytes from $handle and returns the data read.
+# $file_name is used in error messages.
+sub read_fully {
+ my ($handle, $file_name, $bytes) = @_;
+ my ($data);
+ my ($read_bytes) = sysread ($handle, $data, $bytes);
+ die "$file_name: read: $!\n" if !defined $read_bytes;
+ die "$file_name: unexpected end of file\n" if $read_bytes != $bytes;
+ return $data;
+}
+
+# write_fully($handle, $file_name, $data)
+#
+# Write $data to $handle.
+# $file_name is used in error messages.
+sub write_fully {
+ my ($handle, $file_name, $data) = @_;
+ my ($written_bytes) = syswrite ($handle, $data);
+ die "$file_name: write: $!\n" if !defined $written_bytes;
+ die "$file_name: short write\n" if $written_bytes != length $data;
+}
+\f
+# Subprocess utilities.
+
+# run_command(@args)
+#
+# Runs xsystem(@args).
+# Also prints the command it's running and checks that it succeeded.
+sub run_command {
+ print join (' ', @_), "\n";
+ die "command failed\n" if xsystem (@_);
+}
+
+# xsystem(@args)
+#
+# Creates a subprocess via exec(@args) and waits for it to complete.
+# Relays common signals to the subprocess.
+# If $timeout is set then the subprocess will be killed after that long.
+sub xsystem {
+ # QEMU turns off local echo and does not restore it if killed by a signal.
+ # We compensate by restoring it ourselves.
+ my $cleanup = sub {};
+ if (isatty (0)) {
+ my $termios = POSIX::Termios->new;
+ $termios->getattr (0);
+ $cleanup = sub { $termios->setattr (0, &POSIX::TCSANOW); }
+ }
+
+ # Create pipe for filtering output.
+ pipe (my $in, my $out) or die "pipe: $!\n" if $kill_on_failure;
+
+ my ($pid) = fork;
+ if (!defined ($pid)) {
+ # Fork failed.
+ die "fork: $!\n";
+ } elsif (!$pid) {
+ # Running in child process.
+ dup2 (fileno ($out), STDOUT_FILENO) or die "dup2: $!\n"
+ if $kill_on_failure;
+ exec_setitimer (@_);
+ } else {
+ # Running in parent process.
+ close $out if $kill_on_failure;
+
+ my ($cause);
+ local $SIG{ALRM} = sub { timeout ($pid, $cause, $cleanup); };
+ local $SIG{INT} = sub { relay_signal ($pid, "INT", $cleanup); };
+ local $SIG{TERM} = sub { relay_signal ($pid, "TERM", $cleanup); };
+ alarm ($timeout * get_load_average () + 1) if defined ($timeout);
+
+ if ($kill_on_failure) {
+ # Filter output.
+ my ($buf) = "";
+ my ($boots) = 0;
+ local ($|) = 1;
+ for (;;) {
+ if (waitpid ($pid, WNOHANG) != 0) {
+ # Subprocess died. Pass through any remaining data.
+ print $buf while sysread ($in, $buf, 4096) > 0;
+ last;
+ }
+
+ # Read and print out pipe data.
+ my ($len) = length ($buf);
+ waitpid ($pid, 0), last
+ if sysread ($in, $buf, 4096, $len) <= 0;
+ print substr ($buf, $len);
+
+ # Remove full lines from $buf and scan them for keywords.
+ while ((my $idx = index ($buf, "\n")) >= 0) {
+ local $_ = substr ($buf, 0, $idx + 1, '');
+ next if defined ($cause);
+ if (/(Kernel PANIC|User process ABORT)/ ) {
+ $cause = "\L$1\E";
+ alarm (5);
+ } elsif (/Pintos booting/ && ++$boots > 1) {
+ $cause = "triple fault";
+ alarm (5);
+ } elsif (/FAILED/) {
+ $cause = "test failure";
+ alarm (5);
+ }
+ }
+ }
+ } else {
+ waitpid ($pid, 0);
+ }
+ alarm (0);
+ &$cleanup ();
+
+ if (WIFSIGNALED ($?) && WTERMSIG ($?) == SIGVTALRM ()) {
+ seek (STDOUT, 0, 2);
+ print "\nTIMEOUT after $timeout seconds of host CPU time\n";
+ exit 0;
+ }
+
+ return $?;
+ }
+}
+
+# relay_signal($pid, $signal, &$cleanup)
+#
+# Relays $signal to $pid and then reinvokes it for us with the default
+# handler. Also cleans up temporary files and invokes $cleanup.
+sub relay_signal {
+ my ($pid, $signal, $cleanup) = @_;
+ kill $signal, $pid;
+ eval { File::Temp::cleanup() }; # Not defined in old File::Temp.
+ &$cleanup ();
+ $SIG{$signal} = 'DEFAULT';
+ kill $signal, getpid ();
+}
+
+# timeout($pid, $cause, &$cleanup)
+#
+# Interrupts $pid and dies with a timeout error message,
+# after invoking $cleanup.
+sub timeout {
+ my ($pid, $cause, $cleanup) = @_;
+ kill "INT", $pid;
+ waitpid ($pid, 0);
+ &$cleanup ();
+ seek (STDOUT, 0, 2);
+ if (!defined ($cause)) {
+ my ($load_avg) = `uptime` =~ /(load average:.*)$/i;
+ print "\nTIMEOUT after ", time () - $start_time,
+ " seconds of wall-clock time";
+ print " - $load_avg" if defined $load_avg;
+ print "\n";
+ } else {
+ print "Simulation terminated due to $cause.\n";
+ }
+ exit 0;
+}
+
+# Returns the system load average over the last minute.
+# If the load average is less than 1.0 or cannot be determined, returns 1.0.
+sub get_load_average {
+ my ($avg) = `uptime` =~ /load average:\s*([^,]+),/;
+ return $avg >= 1.0 ? $avg : 1.0;
+}
+
+# Calls setitimer to set a timeout, then execs what was passed to us.
+sub exec_setitimer {
+ if (defined $timeout) {
+ if ($\16 ge 5.8.0) {
+ eval "
+ use Time::HiRes qw(setitimer ITIMER_VIRTUAL);
+ setitimer (ITIMER_VIRTUAL, $timeout, 0);
+ ";
+ } else {
+ { exec ("setitimer-helper", $timeout, @_); };
+ exit 1 if !$!{ENOENT};
+ print STDERR "warning: setitimer-helper is not installed, so ",
+ "CPU time limit will not be enforced\n";
+ }
+ }
+ exec (@_);
+ exit (1);
+}
+
+sub SIGVTALRM {
+ use Config;
+ my $i = 0;
+ foreach my $name (split(' ', $Config{sig_name})) {
+ return $i if $name eq 'VTALRM';
+ $i++;
+ }
+ return 0;
+}
+
+# find_in_path ($program)
+#
+# Searches for $program in $ENV{PATH}.
+# Returns $program if found, otherwise undef.
+sub find_in_path {
+ my ($program) = @_;
+ -x "$_/$program" and return $program foreach split (':', $ENV{PATH});
+ return;
+}
projects / pintos-anon / blobdiff