diff options
| -rw-r--r-- | lib/PublicInbox/Lock.pm | 52 |
1 files changed, 29 insertions, 23 deletions
diff --git a/lib/PublicInbox/Lock.pm b/lib/PublicInbox/Lock.pm index 0ee2a8bd..ddaf3312 100644 --- a/lib/PublicInbox/Lock.pm +++ b/lib/PublicInbox/Lock.pm @@ -1,36 +1,42 @@ -# Copyright (C) 2018-2021 all contributors <meta@public-inbox.org> +# Copyright (C) all contributors <meta@public-inbox.org> # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt> -# Base class for per-inbox locking +# Base class for per-inbox locking, subclassed by several +# only uses {lock_path} and {lockfh} fields package PublicInbox::Lock; -use strict; -use v5.10.1; -use Fcntl qw(:flock :DEFAULT); +use v5.12; +use Fcntl qw(LOCK_UN LOCK_EX O_RDWR O_CREAT); use Carp qw(croak); use PublicInbox::OnDestroy; +use Errno qw(EINTR); +use autodie qw(close sysopen syswrite); + +sub xflock ($$) { + until (flock($_[0], $_[1])) { return if $! != EINTR } + 1; +} + +sub new { bless { lock_path => $_[1] }, $_[0] } # we only acquire the flock if creating or reindexing; # PublicInbox::Import already has the lock on its own. sub lock_acquire { my ($self) = @_; - my $lock_path = $self->{lock_path}; - croak 'already locked '.($lock_path // '(undef)') if $self->{lockfh}; - return unless defined($lock_path); - sysopen(my $lockfh, $lock_path, O_RDWR|O_CREAT) or - croak "failed to open $lock_path: $!\n"; - flock($lockfh, LOCK_EX) or croak "lock $lock_path failed: $!\n"; - $self->{lockfh} = $lockfh; + my $fn = $self->{lock_path}; + croak 'already locked '.($fn // '(undef)') if $self->{lockfh}; + $fn // return; + sysopen(my $fh, $fn, O_RDWR|O_CREAT); + xflock($fh, LOCK_EX) or croak "LOCK_EX $fn: $!"; + $self->{lockfh} = $fh; } sub lock_release { my ($self, $wake) = @_; - defined(my $lock_path = $self->{lock_path}) or return; - my $lockfh = delete $self->{lockfh} or croak "not locked: $lock_path"; - - syswrite($lockfh, '.') if $wake; - - flock($lockfh, LOCK_UN) or croak "unlock $lock_path failed: $!\n"; - close $lockfh or croak "close $lock_path failed: $!\n"; + my $fn = $self->{lock_path} // return; + my $fh = delete $self->{lockfh} or croak "not locked: $fn"; + syswrite($fh, '.') if $wake; + xflock($fh, LOCK_UN) or croak "LOCK_UN $fn: $!"; + close $fh; # may detect errors } # caller must use return value @@ -41,13 +47,13 @@ sub lock_for_scope { } sub lock_acquire_fast { - $_[0]->{lockfh} or return lock_acquire($_[0]); - flock($_[0]->{lockfh}, LOCK_EX) or croak "lock (fast) failed: $!"; + my $fh = $_[0]->{lockfh} or return lock_acquire($_[0]); + xflock($fh, LOCK_EX) or croak "LOCK_EX $_[0]->{lock_path}: $!"; } sub lock_release_fast { - flock($_[0]->{lockfh} // return, LOCK_UN) or - croak "unlock (fast) $_[0]->{lock_path}: $!"; + xflock($_[0]->{lockfh} // return, LOCK_UN) or + croak "LOCK_UN $_[0]->{lock_path}: $!" } # caller must use return value |