use flock instead of fcntl locking

We do not need range locking of fcntl locks, so using flock removes
a dependency, hopefully making us easier-to-install.  Also keep in
mind Ruby (and perhaps other scripting language) supports flock
out-of-the-box as well, so it seems flock is easier to support
although fcntl locks offer superior functionality.

diff --git a/Documentation/ssoma_repository.txt b/Documentation/ssoma_repository.txt
index f7b24ada0665bf878fda027f33f3db2ebed6765d..6c6022fd13f5d225f0243283b0cd7bfa01feacaf 100644 (file)
--- a/Documentation/ssoma_repository.txt
+++ b/Documentation/ssoma_repository.txt
@@ -48,7 +48,7 @@ two).
 
 # LOCKING
 
-fcntl(2) locking exclusively locks the empty $GIT_DIR/ssoma.lock file
+flock(2) locking exclusively locks the empty $GIT_DIR/ssoma.lock file
 for all non-atomic operations.
 
 # EXAMPLE INPUT FLOW (SERVER-SIDE MDA)
@@ -61,7 +61,7 @@ ssoma-mda handles all steps once invoked.
 
 2. Mail transport agent invokes ssoma-mda
 3. reads message via stdin, extracting Message-ID
-4. acquires fcntl lock on $GIT_DIR/ssoma.lock
+4. acquires exclusive flock lock on $GIT_DIR/ssoma.lock
 5. creates or updates the blob of associated 2/38 SHA-1 path
 6. updates the index and commits
 7. releases $GIT_DIR/ssoma.lock
@@ -88,7 +88,7 @@ Special files in $GIT_DIR on the server:
 :  The normal git index (in $GIT_DIR/index) is not used at all as
    there is typically no working tree.
 
-* $GIT_DIR/ssoma.lock - empty file for fcntl(2) locking
+* $GIT_DIR/ssoma.lock - empty file for flock(2) locking
 :  This is necessary to ensure the index and commits are updated
    consistently and multiple processes running MDA do not step on
    each other.

diff --git a/INSTALL b/INSTALL
index d21a5c72c527387eb0f97478ba77cd031790f3c7..8f0e378b35fde11857617b716df9391b86ca6dee 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -19,7 +19,6 @@ convenience.
   - Digest::SHA                 perl
   - Email::LocalDelivery        libemail-localdelivery-perl
   - Email::Simple               libemail-simple-perl
-  - File::FcntlLock             libfile-fcntllock-perl
   - File::Path::Expand          libfile-path-expand-perl
   - Net::IMAP::Simple           libnet-imap-simple-perl
 

diff --git a/Makefile.PL b/Makefile.PL
index 7873a54e01720a38b8ad89c06b587c3e1e0c63fd..f500cc04a21101fa30edc5a11299f3903ac5467a 100644 (file)
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -17,7 +17,6 @@ WriteMakefile(
                'Digest::SHA' => 0,
                'Email::LocalDelivery' => 0,
                'Email::Simple' => 0,
-               'File::FcntlLock' => 0,
                'File::Path::Expand' => 0,
                'Net::IMAP::Simple' => 0,
        },

diff --git a/README b/README
index 3aec620b0523916c5f050ba4cb0372441a565211..9c8bfac4c7309c3e79a4a623782a8ab7d99864fa 100644 (file)
--- a/README
+++ b/README
@@ -31,7 +31,6 @@ Requirements (server MDA)
 * MTA - postfix is recommended
 * Perl and several modules:
     - Email::Simple
-    - File::FcntlLock
     - Digest::SHA
 
 Hacking

diff --git a/lib/Ssoma/Git.pm b/lib/Ssoma/Git.pm
index 9a9d82f340fbd40c831d9bcf6f6573c7890c2453..aa63e1db8a866bf6c46e6c736c9dfd4923e66c05 100644 (file)
--- a/lib/Ssoma/Git.pm
+++ b/lib/Ssoma/Git.pm
@@ -13,9 +13,8 @@ package Ssoma::Git;
 use strict;
 use warnings;
 use File::Path qw/mkpath/;
+use Fcntl qw/:DEFAULT :flock SEEK_END/;
 use IO::Handle;
-use Fcntl;
-use File::FcntlLock;
 use Email::Simple;
 use Digest::SHA qw/sha1_hex/;
 
@@ -50,12 +49,6 @@ sub lockfile { $_[0]->{git_dir} . "/ssoma.lock" }
 sub sync_do {
        my ($self, $sub) = @_;
 
-       my $fs = File::FcntlLock->new;
-       $fs->l_type(F_WRLCK);
-       $fs->l_type(SEEK_CUR);
-       $fs->l_start(0);
-       $fs->l_len(0);
-
        my $path = $self->lockfile;
        my $lock;
 
@@ -66,14 +59,14 @@ sub sync_do {
                die "failed to open lock $path: $!\n";
 
        # wait for other processes to be done
-       $fs->lock($lock, F_SETLKW) or die "lock failed: " . $fs->error . "\n";
+       flock($lock, LOCK_EX) or die "lock failed: $!\n";
 
        # run the sub!
        my @ret = eval { &$sub };
        my $err = $@;
 
        # these would happen anyways, but be explicit so we can detect errors
-       $fs->lock($lock, F_UNLCK) or die "unlock failed: " . $fs->error . "\n";
+       flock($lock, LOCK_UN) or die "unlock failed: $!\n";
        close $lock or die "close lockfile($path) failed: $!\n";
 
        die $err if $err;