From 3839498e720151ecc8d623ffc7f87906aa274a8b Mon Sep 17 00:00:00 2001
From: Ralph Boehme <rb@sernet.de>
Date: Thu, 12 Jun 2014 22:40:23 +0200
Subject: [PATCH] Delete 0 byte size resource fork ._ files

Signed-off-by: Ralph Boehme <rb@sernet.de>
Change-Id: ef5f88f5f2cefa75cf20d0ee447b4e20579a2f12
---
 NEWS                        |  1 +
 etc/afpd/ofork.c            | 33 +++++++++++++++++++++++++++++++++
 libatalk/adouble/ad_write.c | 23 ++++++++++++++---------
 3 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/NEWS b/NEWS
index f305674b..138ff03a 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,7 @@ Changes in 3.1.3
 * FIX: afpd: Unarchiving certain ZIP archives fails, bug #569
 * UPD: Update Unicode support to version 7.0.0
 * FIX: Memory overflow caused by 'basedir regex', bug #567
+* NEW: afpd: delete empty resource forks, from FR #94
 
 Changes in 3.1.2
 ================
diff --git a/etc/afpd/ofork.c b/etc/afpd/ofork.c
index 8a04efb9..9d389bb2 100644
--- a/etc/afpd/ofork.c
+++ b/etc/afpd/ofork.c
@@ -23,10 +23,12 @@
 #include <atalk/bstradd.h>
 #include <atalk/globals.h>
 #include <atalk/fce_api.h>
+#include <atalk/ea.h>
 
 #include "volume.h"
 #include "directory.h"
 #include "fork.h"
+#include "desktop.h"
 
 /* we need to have a hashed list of oforks (by dev inode) */
 #define OFORK_HASHSIZE  64
@@ -435,6 +437,37 @@ int of_closefork(const AFPObj *obj, struct ofork *ofork)
 #endif
 
     ret = 0;
+
+    /*
+     * Check for 0 byte size resource forks, delete them.
+     * Here's the deal:
+     * (1) the size must be 0
+     * (2) the fork must refer to a resource fork
+     * (3) the refcount must be 1 which means this fork has the last
+     *     reference to the adouble struct and the subsequent
+     *     ad_close() will close the assoiciated fd.
+     * (4) nobody else has the resource fork open
+     *
+     * We only do this for ._ AppleDouble resource forks, not for
+     * xattr resource forks, because the test-suite then fails several
+     * tests on Solaris, the reason for that still needs to be
+     * determined.
+     */
+    if ((ofork->of_ad->ad_rlen == 0)
+        && (ofork->of_flags & AFPFORK_RSRC)
+        && (ofork->of_ad->ad_rfp->adf_refcount == 1)
+        && (ad_openforks(ofork->of_ad, ATTRBIT_DOPEN) == 0)) {
+
+#ifndef HAVE_EAFD
+        (void)unlink(ofork->of_ad->ad_ops->ad_path(
+                         mtoupath(ofork->of_vol,
+                                  of_name(ofork),
+                                  ofork->of_did,
+                                  utf8_encoding(obj)),
+                         0));
+#endif
+    }
+
     if ( ad_close( ofork->of_ad, adflags | ADFLAGS_SETSHRMD) < 0 ) {
         ret = -1;
     }
diff --git a/libatalk/adouble/ad_write.c b/libatalk/adouble/ad_write.c
index 5cd3742d..4ae1cf60 100644
--- a/libatalk/adouble/ad_write.c
+++ b/libatalk/adouble/ad_write.c
@@ -161,17 +161,22 @@ int ad_rtruncate(struct adouble *ad, const char *uname, const off_t size)
 {
     EC_INIT;
 
-#ifndef HAVE_EAFD
-    if (ad->ad_vers == AD_VERSION_EA && size == 0)
-        EC_NEG1( unlink(ad->ad_ops->ad_path(uname, 0)) );
-    else
-#endif
-        EC_NEG1( sys_ftruncate(ad_reso_fileno(ad), size + ad->ad_eid[ ADEID_RFORK ].ade_off) );
+    /*
+     * We can't delete 0 byte size resource forks either, because a
+     * fork may reference the adouble handle with an open fd for the
+     * file, which means we would only delete the directory entry, not
+     * the file. Subsequently all code that works with fork handles
+     * finds the fork open, so eg flushing a fork (ad_flush()) will
+     * recreate ._ files.  The correct place to delete 0 byte sized
+     * resource forks is in of_closefork().
+     */
+
+    EC_NEG1( sys_ftruncate(ad_reso_fileno(ad), size + ad->ad_eid[ ADEID_RFORK ].ade_off) );
+
+    ad->ad_rlen = size;
 
 EC_CLEANUP:
-    if (ret == 0)
-        ad->ad_rlen = size;    
-    else
+    if (ret != 0)
         LOG(log_error, logtype_ad, "ad_rtruncate(\"%s\"): %s",
             fullpathname(uname), strerror(errno));
     EC_EXIT;
-- 
2.39.2