Restore unlinked UNIX sockets on SIGHUP

Sockets may be unintentionally unlinked on the filesystem.
When reloading our config, ensure that the socket exists
on the filesystem.  If not, close the listener (since it's
unusable by outside apps) and reopen it.

1 files changed, 13 insertions, 4 deletions

diff --git a/lib/unicorn.rb b/lib/unicorn.rb
index 02419e7..2883bc2 100644
--- a/lib/unicorn.rb
+++ b/lib/unicorn.rb
@@ -105,16 +105,25 @@ module Unicorn
     # replaces current listener set with +listeners+.  This will
     # close the socket if it will not exist in the new listener set
     def listeners=(listeners)
-      cur_names = listener_names
+      cur_names, dead_names = [], []
+      listener_names.each do |name|
+        if "/" == name[0..0]
+          # mark unlinked sockets as dead so we can rebind them
+          (File.socket?(name) ? cur_names : dead_names) << name
+        else
+          cur_names << name
+        end
+      end
       set_names = listener_names(listeners)
-      dead_names = cur_names - set_names
+      dead_names += cur_names - set_names
+      dead_names.uniq!
 
       @listeners.delete_if do |io|
         if dead_names.include?(sock_name(io))
           @io_purgatory.delete_if do |pio|
-            pio.fileno == io.fileno && (pio.close rescue nil).nil?
+            pio.fileno == io.fileno && (pio.close rescue nil).nil? # true
           end
-          (io.close rescue nil).nil?
+          (io.close rescue nil).nil? # true
         else
           false
         end