Set FD_CLOEXEC flag on cache files when opened

Changes

@@ -1,5 +1,12 @@
 Revision history for Perl extension Cache::FastMmap.
 
+1.44 Wed Jun 1 21:45 2016
+  - Set FD_CLOEXEC flag on cache files when opened.
+     Particularly useful in Net::Server where
+     HUPing a process causes it to exec() itself.
+     Unless you undef the cache references, you'll
+     leak fd's after each HUP
+
 1.43 Fri Oct 23 14:00 2015
   - Update copyright + version correctly everywhere
 

META.yml

@@ -1,7 +1,7 @@
 # http://module-build.sourceforge.net/META-spec.html
 #XXXXXXX This is a prototype!!!  It will change in the future!!! XXXXX#
 name:         Cache-FastMmap
-version:      1.43
+version:      1.44
 version_from: FastMmap.pm
 installdirs:  site
 requires:

lib/Cache/FastMmap.pm

@@ -293,7 +293,7 @@ use strict;
 use warnings;
 use bytes;
 
-our $VERSION = '1.43';
+our $VERSION = '1.44';
 
 require XSLoader;
 XSLoader::load('Cache::FastMmap', $VERSION);

t/18.t

@@ -0,0 +1,63 @@
+
+#########################
+
+use Test::More;
+
+BEGIN {
+  if ($^O eq "MSWin32") {
+    plan skip_all => 'No FD_CLOEXEC tests, running on Windows';
+  }
+  if (!-d "/proc/$$") {
+    plan skip_all => 'No FD_CLOEXEC tests, no /proc filesystem';
+  }
+}
+
+
+use strict;
+use Fcntl;
+
+#########################
+
+# Test fd's are closed on exec
+
+if (@ARGV) {
+  my $PipeFd = shift @ARGV;
+  my $FdCount = scalar(() = glob "/proc/$$/fd/*");
+  open(my $PipeFh, ">&=$PipeFd")
+    || die "Could not reopen fd: $!";
+  print($PipeFh "$FdCount\n")
+    || die "Could not print to pipe: $!";
+  exit(0);
+}
+
+require Cache::FastMmap;
+my @Caches = map {
+  Cache::FastMmap->new(
+    page_size => 4096,
+    num_pages => 1,
+    init_file => 1,
+    raw_values => 1,
+  );
+} (1 .. 20);
+my $CacheCount = @Caches;
+
+my $FdCount = scalar(() = glob "/proc/$$/fd/*");
+ok($FdCount > $CacheCount, "More fd's than caches: $FdCount > $CacheCount");
+
+pipe(my $ReadPipeFh, my $WritePipeFh)
+  || die "pipe failed: $!";
+
+fcntl($ReadPipeFh, F_SETFD, 0);
+fcntl($WritePipeFh, F_SETFD, 0);
+
+if (!fork) {
+  exec $^X, $0, fileno($WritePipeFh)
+    || die "exec failed: $!";
+}
+
+my $ChildFdCount = <$ReadPipeFh>;
+chomp $ChildFdCount;
+ok($ChildFdCount < $CacheCount, "Less fd's in child than caches: $ChildFdCount < $CacheCount");
+
+done_testing(2);
+

unix.c

@@ -94,6 +94,9 @@ int mmc_open_cache_file(mmap_cache* cache, int * do_init) {
     return -1;
   }
 
+  /* Automatically close cache fd on exec */
+  fcntl(fh, F_SETFD, FD_CLOEXEC);
+
   cache->fh = fh;
 
   return 0;