--- /dev/null
+# Pintos helper subroutines.
+
+# Number of bytes available for the loader at the beginning of the MBR.
+# Kernel command-line arguments follow the loader.
+our $LOADER_SIZE = 314;
+
+# Partition types.
+my (%role2type) = (KERNEL => 0x20,
+ FILESYS => 0x21,
+ SCRATCH => 0x22,
+ SWAP => 0x23);
+my (%type2role) = reverse %role2type;
+
+# Order of roles within a given disk.
+our (@role_order) = qw (KERNEL FILESYS SCRATCH SWAP);
+
+# Partitions.
+#
+# Valid keys are KERNEL, FILESYS, SCRATCH, SWAP. Only those
+# partitions which are in use are included.
+#
+# Each value is a reference to a hash. If the partition's contents
+# are to be obtained from a file (that will be copied into a new
+# virtual disk), then the hash contains:
+#
+# FILE => name of file from which the partition's contents are copied
+# (perhaps "/dev/zero"),
+# OFFSET => offset in bytes in FILE,
+# BYTES => size in bytes of contents from FILE,
+#
+# If the partition is taken from a virtual disk directly, then it
+# contains the following. The same keys are also filled in once a
+# file-based partition has been copied into a new virtual disk:
+#
+# DISK => name of virtual disk file,
+# START => sector offset of start of partition within DISK,
+# SECTORS => number of sectors of partition within DISK, which is usually
+# greater than round_up (BYTES, 512) due to padding.
+our (%parts);
+
+# set_part($opt, $arg)
+#
+# For use as a helper function for Getopt::Long::GetOptions to set
+# disk sources.
+sub set_part {
+ my ($opt, $arg) = @_;
+ my ($role, $source) = $opt =~ /^([a-z]+)(?:-([a-z]+))?/ or die;
+
+ $role = uc $role;
+ $source = 'FILE' if $source eq '';
+
+ die "can't have two sources for \L$role\E partition"
+ if exists $parts{$role};
+
+ do_set_part ($role, $source, $arg);
+}
+
+# do_set_part($role, $source, $arg)
+#
+# Sets partition $role as coming from $source (one of 'file', 'from',
+# or 'size'). $arg is a file name for 'file' or 'from', a size in
+# megabytes for 'size'.
+sub do_set_part {
+ my ($role, $source, $arg) = @_;
+
+ my ($p) = $parts{$role} = {};
+ if ($source eq 'file') {
+ if (read_mbr ($arg)) {
+ print STDERR "warning: $arg looks like a partitioned disk ";
+ print STDERR "(did you want --$role-from=$arg or --disk=$arg?)\n"
+ }
+
+ $p->{FILE} = $arg;
+ $p->{OFFSET} = 0;
+ $p->{BYTES} = -s $arg;
+ } elsif ($source eq 'from') {
+ my (%pt) = read_partition_table ($arg);
+ my ($sp) = $pt{$role};
+ die "$arg: does not contain \L$role\E partition\n" if !defined $sp;
+
+ $p->{FILE} = $arg;
+ $p->{OFFSET} = $sp->{START} * 512;
+ $p->{BYTES} = $sp->{SECTORS} * 512;
+ } elsif ($source eq 'size') {
+ $arg =~ /^\d+(\.\d+)?|\.\d+$/ or die "$arg: not a valid size in MB\n";
+
+ $p->{FILE} = "/dev/zero";
+ $p->{OFFSET} = 0;
+ $p->{BYTES} = ceil ($arg * 1024 * 1024);
+ } else {
+ die;
+ }
+}
+
+# set_geometry('HEADS,SPT')
+# set_geometry('zip')
+#
+# For use as a helper function for Getopt::Long::GetOptions to set
+# disk geometry.
+sub set_geometry {
+ local ($_) = $_[1];
+ if ($_ eq 'zip') {
+ @geometry{'H', 'S'} = (64, 32);
+ } else {
+ @geometry{'H', 'S'} = /^(\d+)[,\s]+(\d+)$/
+ or die "bad syntax for geometry\n";
+ $geometry{H} <= 255 or die "heads limited to 255\n";
+ $geometry{S} <= 63 or die "sectors per track limited to 63\n";
+ }
+}
+
+# set_align('bochs|full|none')
+#
+# For use as a helper function for Getopt::Long::GetOptions to set
+# partition alignment.
+sub set_align {
+ $align = $_[1];
+ die "unknown alignment type \"$align\"\n"
+ if $align ne 'bochs' && $align ne 'full' && $align ne 'none';
+}
+
+# assemble_disk(%args)
+#
+# Creates a virtual disk $args{DISK} containing the partitions
+# described by @args{KERNEL, FILESYS, SCRATCH, SWAP}.
+#
+# Required arguments:
+# DISK => output disk file name
+# HANDLE => output file handle (will be closed)
+#
+# Normally at least one of the following is included:
+# KERNEL, FILESYS, SCRATCH, SWAP => {input:
+# FILE => file to read,
+# OFFSET => byte offset in file,
+# BYTES => byte count from file,
+#
+# output:
+# DISK => output disk file name,
+# START => sector offset in DISK,
+# SECTORS => sector count in DISK},
+#
+# Optional arguments:
+# ALIGN => 'bochs' (default), 'full', or 'none'
+# GEOMETRY => {H => heads, S => sectors per track} (default 16, 63)
+# FORMAT => 'partitioned' (default) or 'raw'
+# LOADER => $LOADER_SIZE-byte string containing the loader binary
+# ARGS => ['arg 1', 'arg 2', ...]
+sub assemble_disk {
+ my (%args) = @_;
+
+ my (%geometry) = $args{GEOMETRY} || (H => 16, S => 63);
+
+ my ($align); # Align partition start, end to cylinder boundary?
+ my ($pad); # Pad end of disk out to cylinder boundary?
+ if (!defined ($args{ALIGN}) || $args{ALIGN} eq 'bochs') {
+ $align = 0;
+ $pad = 1;
+ } elsif ($args{ALIGN} eq 'full') {
+ $align = 1;
+ $pad = 0;
+ } elsif ($args{ALIGN} eq 'none') {
+ $align = $pad = 0;
+ } else {
+ die;
+ }
+
+ my ($format) = $args{FORMAT} || 'partitioned';
+ die if $format ne 'partitioned' && $format ne 'raw';
+
+ # Check that we have apartitions to copy in.
+ my $part_cnt = grep (defined ($args{$_}), keys %role2type);
+ die "must have exactly one partition for raw output\n"
+ if $format eq 'raw' && $part_cnt != 1;
+
+ # Calculate the disk size.
+ my ($total_sectors) = 0;
+ if ($format eq 'partitioned') {
+ $total_sectors += $align ? $geometry{S} : 1;
+ }
+ for my $role (@role_order) {
+ my ($p) = $args{$role};
+ next if !defined $p;
+
+ die if $p->{DISK};
+
+ my ($bytes) = $p->{BYTES};
+ my ($start) = $total_sectors;
+ my ($end) = $start + div_round_up ($bytes, 512);
+ $end = round_up ($end, cyl_sectors (%geometry)) if $align;
+
+ $p->{DISK} = $args{DISK};
+ $p->{START} = $start;
+ $p->{SECTORS} = $end - $start;
+ $total_sectors = $end;
+ }
+
+ # Write the disk.
+ my ($disk_fn) = $args{DISK};
+ my ($disk) = $args{HANDLE};
+ if ($format eq 'partitioned') {
+ # Pack loader into MBR.
+ my ($loader) = $args{LOADER} || "\xcd\x18";
+ my ($mbr) = pack ("a$LOADER_SIZE", $loader);
+
+ $mbr .= make_kernel_command_line (@{$args{ARGS}});
+
+ # Pack partition table into MBR.
+ $mbr .= make_partition_table (\%geometry, \%args);
+
+ # Add signature to MBR.
+ $mbr .= pack ("v", 0xaa55);
+
+ die if length ($mbr) != 512;
+ write_fully ($disk, $disk_fn, $mbr);
+ write_zeros ($disk, $disk_fn, 512 * ($geometry{S} - 1)) if $align;
+ }
+ for my $role (@role_order) {
+ my ($p) = $args{$role};
+ next if !defined $p;
+
+ my ($source);
+ my ($fn) = $p->{FILE};
+ open ($source, '<', $fn) or die "$fn: open: $!\n";
+ if ($p->{OFFSET}) {
+ sysseek ($source, $p->{OFFSET}, 0) == $p->{OFFSET}
+ or die "$fn: seek: $!\n";
+ }
+ copy_file ($source, $fn, $disk, $disk_fn, $p->{BYTES});
+ close ($source) or die "$fn: close: $!\n";
+
+ write_zeros ($disk, $disk_fn, $p->{SECTORS} * 512 - $p->{BYTES});
+ }
+ if ($pad) {
+ my ($pad_sectors) = round_up ($total_sectors, cyl_sectors (%geometry));
+ write_zeros ($disk, $disk_fn, ($pad_sectors - $total_sectors) * 512);
+ }
+ close ($disk) or die "$disk: close: $!\n";
+}
+
+# make_partition_table({H => heads, S => sectors}, {KERNEL => ..., ...})
+#
+# Creates and returns a partition table for the given partitions and
+# disk geometry.
+sub make_partition_table {
+ my ($geometry, $partitions) = @_;
+ my ($table) = '';
+ for my $role (@role_order) {
+ defined (my $p = $partitions->{$role}) or next;
+
+ my $end = $p->{START} + $p->{SECTORS} - 1;
+ my $bootable = $role eq 'KERNEL';
+
+ $table .= pack ("C", $bootable ? 0x80 : 0); # Bootable?
+ $table .= pack_chs ($p->{START}, $geometry); # CHS of partition start
+ $table .= pack ("C", $role2type{$role}); # Partition type
+ $table .= pack_chs($end, $geometry); # CHS of partition end
+ $table .= pack ("V", $p->{START}); # LBA of partition start
+ $table .= pack ("V", $p->{SECTORS}); # Length in sectors
+ die if length ($table) % 16;
+ }
+ return pack ("a64", $table);
+}
+
+# make_kernel_command_line(@args)
+#
+# Returns the raw bytes to write to an MBR at offset $LOADER_SIZE to
+# set a Pintos kernel command line.
+sub make_kernel_command_line {
+ my (@args) = @_;
+ my ($args) = join ('', map ("$_\0", @args));
+ die "command line exceeds 128 bytes" if length ($args) > 128;
+ return pack ("V a128", scalar (@args), $args);
+}
+
+# copy_file($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 $data;
+}
+
+sub write_zeros {
+ my ($handle, $file_name, $size) = @_;
+
+ while ($size > 0) {
+ my ($chunk_size) = 4096;
+ $chunk_size = $size if $chunk_size > $size;
+ $size -= $chunk_size;
+
+ write_fully ($handle, $file_name, "\0" x $chunk_size);
+ }
+}
+
+# div_round_up($x,$y)
+#
+# Returns $x / $y, rounded up to the nearest integer.
+# $y must be an integer.
+sub div_round_up {
+ my ($x, $y) = @_;
+ return int ((ceil ($x) + $y - 1) / $y);
+}
+
+# round_up($x, $y)
+#
+# Returns $x rounded up to the nearest multiple of $y.
+# $y must be an integer.
+sub round_up {
+ my ($x, $y) = @_;
+ return div_round_up ($x, $y) * $y;
+}
+
+# cyl_sectors(H => heads, S => sectors)
+#
+# Returns the number of sectors in a cylinder of a disk with the given
+# geometry.
+sub cyl_sectors {
+ my (%geometry) = @_;
+ return $geometry{H} * $geometry{S};
+}
+
+# read_loader($file_name)
+#
+# Reads and returns the first $LOADER_SIZE bytes in $file_name.
+# If $file_name is undefined, tries to find the default loader.
+# Makes sure that the loader is a reasonable size.
+sub read_loader {
+ my ($name) = @_;
+ $name = find_file ("loader.bin") if !defined $name;
+ die "Cannot find loader\n" if !defined $name;
+
+ my ($handle);
+ open ($handle, '<', $name) or die "$name: open: $!\n";
+ -s $handle == $LOADER_SIZE || -s $handle == 512
+ or die "$name: must be exactly $LOADER_SIZE or 512 bytes long\n";
+ $loader = read_fully ($handle, $name, $LOADER_SIZE);
+ close ($handle) or die "$name: close: $!\n";
+ return $loader;
+}
+
+# pack_chs($lba, {H => heads, S => sectors})
+#
+# Converts logical sector $lba to a 3-byte packed geometrical sector
+# in the format used in PC partition tables (see [Partitions]) and
+# returns the geometrical sector as a 3-byte string.
+sub pack_chs {
+ my ($lba, $geometry) = @_;
+ my ($cyl, $head, $sect) = lba_to_chs ($lba, $geometry);
+ return pack ("CCC", $head, $sect | (($cyl >> 2) & 0xc0), $cyl & 0xff);
+}
+
+# lba_to_chs($lba, {H => heads, S => sectors})
+#
+# Returns the geometrical sector corresponding to logical sector $lba
+# given the specified geometry.
+sub lba_to_chs {
+ my ($lba, $geometry) = @_;
+ my ($hpc) = $geometry->{H};
+ my ($spt) = $geometry->{S};
+
+ # Source:
+ # http://en.wikipedia.org/wiki/CHS_conversion
+ use integer;
+ my $cyl = $lba / ($hpc * $spt);
+ my $temp = $lba % ($hpc * $spt);
+ my $head = $temp / $spt;
+ my $sect = $temp % $spt + 1;
+
+ # Source:
+ # http://www.cgsecurity.org/wiki/Intel_Partition_Table
+ if ($cyl <= 1023) {
+ return ($cyl, $head, $sect);
+ } else {
+ return (1023, 254, 63); ## or should this be (1023, $hpc, $spt)?
+ }
+}
+
+# read_mbr($file)
+#
+# Tries to read an MBR from $file. Returns the 512-byte MBR if
+# successful, otherwise numeric 0.
+sub read_mbr {
+ my ($file) = @_;
+ my ($retval) = 0;
+ open (FILE, '<', $file) or die "$file: open: $!\n";
+ if (-s FILE == 0) {
+ die "$file: file has zero size\n";
+ } elsif (-s FILE >= 512) {
+ my ($mbr);
+ sysread (FILE, $mbr, 512) == 512 or die "$file: read: $!\n";
+ $retval = $mbr if unpack ("v", substr ($mbr, 510)) == 0xaa55;
+ }
+ close (FILE);
+ return $retval;
+}
+
+# interpret_partition_table($mbr, $disk)
+#
+# Parses the partition-table in the specified 512-byte $mbr and
+# returns the partitions. $disk is used for error messages.
+sub interpret_partition_table {
+ my ($mbr, $disk) = @_;
+ my (%parts);
+ for my $i (0...3) {
+ my ($bootable, $valid, $type, $lba_start, $lba_length)
+ = unpack ("C X V C x3 V V", substr ($mbr, 446 + 16 * $i, 16));
+ next if !$valid;
+
+ (print STDERR "warning: invalid partition entry $i in $disk\n"),
+ next if $bootable != 0 && $bootable != 0x80;
+
+ my ($role) = $type2role{$type};
+ (printf STDERR "warning: non-Pintos partition type 0x%02x in %s\n",
+ $type, $disk),
+ next if !defined $role;
+
+ (print STDERR "warning: duplicate \L$role\E partition in $disk\n"),
+ next if exists $parts{$role};
+
+ $parts{$role} = {START => $lba_start,
+ SECTORS => $lba_length};
+ }
+ return %parts;
+}
+
+# find_file($base_name)
+#
+# Looks for a file named $base_name in a couple of likely spots. If
+# found, returns the name; otherwise, returns undef.
+sub find_file {
+ my ($base_name) = @_;
+ -e && return $_ foreach $base_name, "build/$base_name";
+ return undef;
+}
+
+# read_partition_table($file)
+#
+# Reads a partition table from $file and returns the parsed
+# partitions. Dies if partitions can't be read.
+sub read_partition_table {
+ my ($file) = @_;
+ my ($mbr) = read_mbr ($file);
+ die "$file: not a partitioned disk\n" if !$mbr;
+ return interpret_partition_table ($mbr, $file);
+}
+
+# max(@args)
+#
+# Returns the numerically largest value in @args.
+sub max {
+ my ($max) = $_[0];
+ foreach (@_[1..$#_]) {
+ $max = $_ if $_ > $max;
+ }
+ return $max;
+}
+
+1;
projects / pintos-anon / blobdiff