package swap; use diagnostics; use strict; use common qw(:common :system :constant); use log; use devices; use c; my $pagesize = c::getpagesize(); my $signature_page = "\0" x $pagesize; # Maximum allowable number of pages in one swap. # From 2.2.0 onwards, this depends on how many offset bits # the architectures can actually store into the page tables # and on 32bit architectures it is limited to 2GB at the # same time. # Old swap format keeps the limit of 8*pagesize*(pagesize - 10) my $V0_MAX_PAGES = 8 * $pagesize - 10; my $V1_OLD_MAX_PAGES = int 0x7fffffff / $pagesize - 1; my $V1_MAX_PAGES = $V1_OLD_MAX_PAGES; #- (1 << 24) - 1; my $MAX_BADPAGES = int ($pagesize - 1024 - 128 * $common::sizeof_int - 10) / $common::sizeof_int; my $signature_format_v1 = "x1024 I I I I125"; #- bootbits, version, last_page, nr_badpages, padding 1; sub kernel_greater_or_equal($$$) { c::kernel_version() =~ /(\d*)\.(\d*)\.(\d*)/; ($1 <=> $_[0] || $2 <=> $_[1] || $3 <=> $_[2]) >= 0; } sub check_blocks { my ($fd, $version, $nbpages) = @_; my ($last_read_ok, $badpages) = (0, 0); my ($buffer); my $badpages_field_v1 = \substr($signature_page, psizeof($signature_format_v1)); for (my $i = 0; $i < $nbpages; $i++) { $last_read_ok || sysseek($fd, $i * $pagesize, 0) or die "seek failed"; unless ($last_read_ok = sysread($fd, $buffer, $pagesize)) { if ($version == 1) { $badpages == $MAX_BADPAGES and die "too many bad pages"; vec($$badpages_field_v1, $badpages, $bitof_int) = $i; } $badpages++; } vec($signature_page, $i, 1) = bool($last_read_ok) if $version == 0; } #- TODO: add interface $badpages and log::l("$badpages bad pages\n"); return $badpages; } sub make($;$) { my ($devicename, $checkBlocks) = @_; my $tmpdev = 0; my $badpages = 0; my ($version, $maxpages); $devicename = devices::make($devicename); my $nbpages = divide(devices::size($devicename), $pagesize); if ($nbpages <= $V0_MAX_PAGES || !kernel_greater_or_equal(2,1,117) || $pagesize < 2048) { $version = 0; } else { $version = 1; } $nbpages >= 10 or die "swap area needs to be at least " . (10 * $pagesize >> 10) . "kB"; -b $devicename or $checkBlocks = 0; my $rdev = (stat $devicename)[6];# or log::l("stat of $devicename failed: $!"); $rdev == 0x300 || $rdev == 0x340 and die "$devicename is not a good device for swap"; sysopen F, $devicename, 2 or die "opening $devicename for writing failed: $!"; if ($version == 0) { $maxpages = $V0_MAX_PAGES; } elsif (kernel_greater_or_equal(2,2,1)) { $maxpages = $V1_MAX_PAGES; } else { $maxpages = min($V1_OLD_MAX_PAGES, $V1_MAX_PAGES); } if ($nbpages > $maxpages) { $nbpages = $maxpages; log::l("warning: truncating swap area to " . ($nbpages * $pagesize >> 10) . "kB"); } if ($checkBlocks) { $badpages = check_blocks(*F, $version, $nbpages); } elsif ($version == 0) { for (my $i = 0; $i < $nbpages; $i++) { vec($signature_page, $i, 1) = 1; } } $version == 0 and !vec($signature_page, 0, 1) and die "bad block on first page"; vec($signature_page, 0, 1) = 0; $version == 1 and strcpy($signature_page, pack($signature_format_v1, $version, $nbpages - 1, $badpages)); my $goodpages = $nbpages - $badpages - 1; $goodpages > 0 or die "all blocks are bad"; log::l("Setting up swapspace on $devicename version $version, size = " . $goodpages * $pagesize . " bytes"); strcpy($signature_page, $version == 0 ? "SWAP-SPACE" : "SWAPSPACE2", $pagesize - 10); my $offset = ($version == 0) ? 0 : 1024; sysseek(F, $offset, 0) or die "unable to rewind swap-device: $!"; syswrite(F, substr($signature_page, $offset)) or die "unable to write signature page: $!"; #- A subsequent swapon() will fail if the signature is not actually on disk. (This is a kernel bug.) syscall_('fsync', fileno(F)) or die "fsync failed: $!"; close F; } sub enable($;$) { my ($devicename, $checkBlocks) = @_; make($devicename, $checkBlocks); swapon($devicename); } sub swapon($) { syscall_('swapon', devices::make($_[0]), 0) or die "swapon($_[0]) failed: $!"; } sub swapoff($) { syscall_('swapoff', devices::make($_[0])) or die "swapoff($_[0]) failed: $!"; } form for many utilitiesThierry Vignaud [tv]
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authorPablo Saratxaga <pablo@mandriva.com>2002-08-21 14:59:35 +0000
committerPablo Saratxaga <pablo@mandriva.com>2002-08-21 14:59:35 +0000
commitbf0c0181a9daa78515c6c6975142ba761e1e060c (patch)
tree785b9932488cf96b6a8dec9685271f224a8fb95f
parentfe3f4e3c2c8b30053eb817c7f4a47f8db17ea86e (diff)
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