package urpm::lock; # $Id: lock.pm 261997 2009-10-15 17:44:35Z cfergeau $ use strict; use urpm::msg; #- avoid putting a require on Fcntl ':flock' (which is perl and not perl-base). my ($LOCK_SH, $LOCK_EX, $LOCK_NB, $LOCK_UN) = (1, 2, 4, 8); ################################################################################ #- class functions #- lock policy concerning chroot : # - lock rpm db in chroot # - lock urpmi db in / # (options: nofatal, wait) sub rpm_db { my ($urpm, $b_exclusive, %options) = @_; my $f = ($urpm->{root} ? "$urpm->{root}/" : '') . "/var/lib/rpm/.RPMLOCK"; urpm::lock->new($urpm, $f, 'rpm', $b_exclusive, %options); } # (options: nofatal, wait) sub urpmi_db { my ($urpm, $b_exclusive, %options) = @_; urpm::lock->new($urpm, "$urpm->{statedir}/.LOCK", 'urpmi', $b_exclusive, %options); } ################################################################################ #- methods # (options: nofatal, wait) sub new { my ($_class, $urpm, $file, $db_name, $b_exclusive, %options) = @_; my $fh; #- we don't care what the mode is. ">" allow creating the file, but can't be done as user open($fh, '>', $file) or open($fh, '<', $file) or return; my $lock = bless { fh => $fh, db_name => $db_name, fatal => $options{nofatal} ? $urpm->{error} : sub { $urpm->{fatal}(7, $_[0]) }, info => $urpm->{info}, log => $urpm->{log}, }; _lock($lock, $b_exclusive, $options{wait}); $lock; } sub get_lock_pid { my ($fh) = @_; my ($dev,$ino,undef) = stat($fh); my $major = int($dev/256); my $minor = $dev % 256; my $fileid = sprintf("%02x:%02x:%d",$major,$minor,$ino); open(LOCKS, "/proc/locks") || return; my @locks = ; close(LOCKS); foreach (@locks) { /FLOCK.*WRITE\s*(\d+)\s*$fileid\s/ && return $1 }; } sub _lock { my ($lock, $b_exclusive, $b_wait) = @_; $b_exclusive ||= ''; if ($lock->{log}) { my $action = $lock->{exclusive} && !$b_exclusive ? 'releasing exclusive' : $b_exclusive ? 'getting exclusive' : 'getting'; $lock->{log}("$action lock on $lock->{db_name}"); } my $mode = $b_exclusive ? $LOCK_EX : $LOCK_SH; if (!flock($lock->{fh}, $mode | $LOCK_NB)) { if ($b_wait) { $lock->{info}(N("%s database is locked. Waiting...", $lock->{db_name})); flock($lock->{fh}, $mode) or $lock->{fatal}(N("aborting")); } else { my $pid = get_lock_pid($lock->{fh}); if($pid) { my $name = urpm::util::cat_("/proc/$pid/cmdline"); $name =~ tr/\0/ /; $name =~ s/ *$//; $lock->{fatal}(N("%s database is locked, process %d is already using it", $lock->{db_name}, $pid).($name?" ($name)":"")); } else { $lock->{fatal}(N("%s database is locked (another program is already using it)", $lock->{db_name})); } } } $lock->{locked} = 1; $lock->{exclusive} = $b_exclusive; } sub unlock { my ($lock) = @_; $lock->{fh} or warn "lock $lock->{db_name} already released\n", return; if ($lock->{locked}) { $lock->{log} and $lock->{log}("unlocking $lock->{db_name} database"); flock $lock->{fh}, $LOCK_UN; } close $lock->{fh}; delete $lock->{fh}; } sub DESTROY { my ($lock) = @_; unlock($lock) if $lock->{fh}; }