From: Timo Sirainen <tss@iki.fi>
Date: Tue, 13 Apr 2010 09:33:17 +0000 (+0300)
Subject: dbox: Use flock() for file locking if possible. If not, require client_limit=1.
X-Git-Tag: 2.0.beta5~142
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=bca919b207e27d0d08b431bdb0f2ac099ef8b512;p=thirdparty%2Fdovecot%2Fcore.git

dbox: Use flock() for file locking if possible. If not, require client_limit=1.
Maybe some day dbox code can be redesigned in a way that allows it to work
with fcntl() locking too.

--HG--
branch : HEAD
---

diff --git a/src/lib-storage/index/dbox-common/dbox-file.c b/src/lib-storage/index/dbox-common/dbox-file.c
index f474294a76..22eda6bda7 100644
--- a/src/lib-storage/index/dbox-common/dbox-file.c
+++ b/src/lib-storage/index/dbox-common/dbox-file.c
@@ -24,6 +24,14 @@
 
 #define DBOX_READ_BLOCK_SIZE 4096
 
+/* prefer flock(). fcntl() locking currently breaks if trying to access the
+   same file from multiple mail_storages within same process. */
+#ifdef HAVE_FLOCK
+#  define DBOX_FILE_LOCK_METHOD FILE_LOCK_METHOD_FLOCK
+#else
+#  define DBOX_FILE_LOCK_METHOD FILE_LOCK_METHOD_FCNTL
+#endif
+
 const char *dbox_generate_tmp_filename(void)
 {
 	static unsigned int create_count = 0;
@@ -291,7 +299,7 @@ int dbox_file_try_lock(struct dbox_file *file)
 	i_assert(file->fd != -1);
 
 	ret = file_try_lock(file->fd, file->cur_path, F_WRLCK,
-			    FILE_LOCK_METHOD_FCNTL, &file->lock);
+			    DBOX_FILE_LOCK_METHOD, &file->lock);
 	if (ret < 0) {
 		mail_storage_set_critical(&file->storage->storage,
 			"file_try_lock(%s) failed: %m", file->cur_path);
diff --git a/src/lib-storage/index/dbox-multi/Makefile.am b/src/lib-storage/index/dbox-multi/Makefile.am
index 89dcd34f8b..ccc5d67cb6 100644
--- a/src/lib-storage/index/dbox-multi/Makefile.am
+++ b/src/lib-storage/index/dbox-multi/Makefile.am
@@ -3,6 +3,7 @@ noinst_LTLIBRARIES = libstorage_dbox_multi.la
 AM_CPPFLAGS = \
 	-I$(top_srcdir)/src/lib \
 	-I$(top_srcdir)/src/lib-settings \
+	-I$(top_srcdir)/src/lib-master \
 	-I$(top_srcdir)/src/lib-mail \
 	-I$(top_srcdir)/src/lib-imap \
 	-I$(top_srcdir)/src/lib-index \
diff --git a/src/lib-storage/index/dbox-multi/mdbox-storage.c b/src/lib-storage/index/dbox-multi/mdbox-storage.c
index f4fcab0e23..99ce0c93b1 100644
--- a/src/lib-storage/index/dbox-multi/mdbox-storage.c
+++ b/src/lib-storage/index/dbox-multi/mdbox-storage.c
@@ -4,6 +4,7 @@
 #include "array.h"
 #include "ioloop.h"
 #include "mkdir-parents.h"
+#include "master-service.h"
 #include "mail-index-modseq.h"
 #include "mail-index-alloc-cache.h"
 #include "mailbox-log.h"
@@ -46,6 +47,14 @@ mdbox_storage_create(struct mail_storage *_storage, struct mail_namespace *ns,
 		return -1;
 	}
 
+#ifndef HAVE_FLOCK
+	if (master_service_get_client_limit(master_service) > 1) {
+		*error_r = "mdbox requires client_limit=1 for service "
+			"since your OS doesn't support flock()";
+		return -1;
+	}
+#endif
+
 	_storage->unique_root_dir =
 		p_strdup(_storage->pool, ns->list->set.root_dir);
 
diff --git a/src/lib-storage/index/dbox-single/Makefile.am b/src/lib-storage/index/dbox-single/Makefile.am
index e8f54ff663..d810f5b183 100644
--- a/src/lib-storage/index/dbox-single/Makefile.am
+++ b/src/lib-storage/index/dbox-single/Makefile.am
@@ -3,6 +3,7 @@ noinst_LTLIBRARIES = libstorage_dbox_single.la
 AM_CPPFLAGS = \
 	-I$(top_srcdir)/src/lib \
 	-I$(top_srcdir)/src/lib-settings \
+	-I$(top_srcdir)/src/lib-master \
 	-I$(top_srcdir)/src/lib-mail \
 	-I$(top_srcdir)/src/lib-imap \
 	-I$(top_srcdir)/src/lib-index \
diff --git a/src/lib-storage/index/dbox-single/sdbox-storage.c b/src/lib-storage/index/dbox-single/sdbox-storage.c
index f315e63180..953cca6550 100644
--- a/src/lib-storage/index/dbox-single/sdbox-storage.c
+++ b/src/lib-storage/index/dbox-single/sdbox-storage.c
@@ -1,6 +1,7 @@
 /* Copyright (c) 2007-2010 Dovecot authors, see the included COPYING file */
 
 #include "lib.h"
+#include "master-service.h"
 #include "mail-index-modseq.h"
 #include "dbox-mail.h"
 #include "dbox-save.h"
@@ -25,6 +26,21 @@ static struct mail_storage *sdbox_storage_alloc(void)
 	return &storage->storage.storage;
 }
 
+static int
+sdbox_storage_create(struct mail_storage *storage ATTR_UNUSED,
+		     struct mail_namespace *ns ATTR_UNUSED,
+		     const char **error_r ATTR_UNUSED)
+{
+#ifndef HAVE_FLOCK
+	if (master_service_get_client_limit(master_service) > 1) {
+		*error_r = "dbox requires client_limit=1 for service "
+			"since your OS doesn't support flock()";
+		return -1;
+	}
+#endif
+	return 0;
+}
+
 static struct mailbox *
 sdbox_mailbox_alloc(struct mail_storage *storage, struct mailbox_list *list,
 		    const char *name, enum mailbox_flags flags)
@@ -211,7 +227,7 @@ struct mail_storage dbox_storage = {
 	.v = {
                 NULL,
 		sdbox_storage_alloc,
-		NULL,
+		sdbox_storage_create,
 		NULL,
 		NULL,
 		dbox_storage_get_list_settings,