Generic bi-directional map, and related initialisation functions. At the moment

a single map is used to store mappings between sharing handles and disk blocks.
This is used to share pages which store data read of the same blocks on
(virtual) disk.
Note that the map is stored in a shared memory region, as it needs to be
accessed by multiple tapdisk processes. This complicates memory allocation
(malloc cannot be used), prevents poniters to be stored directly (as the shared
memory region might and is mapped at different base address) and finally pthread
locks need to be multi-process aware.

Signed-off-by: Grzegorz Milos <Grzegorz.Milos@citrix.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/tools/memshr/shm.h b/tools/memshr/shm.h
new file mode 100644
index 0000000000..0f6f665c6d
--- /dev/null
+++ b/tools/memshr/shm.h
@@ -0,0 +1,35 @@
+/******************************************************************************
+ *
+ * Copyright (c) 2009 Citrix (R&D) Inc. (Grzegorz Milos)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#ifndef __SHM_H__
+#define __SHM_H__
+
+#include <pthread.h>
+
+typedef struct shared_memshr_info {
+    unsigned long   magic;
+    pthread_mutex_t lock;
+    int             fgprtshr_hash_inited;
+    int             blockshr_hash_inited;
+} shared_memshr_info_t;
+
+shared_memshr_info_t * shm_shared_info_open(int unlink);
+struct fgprtshr_hash * shm_fgprtshr_hash_open(int unlink);
+struct blockshr_hash * shm_blockshr_hash_open(int unlink);
+
+#endif /* __SHM_H__ */