From: Stefan Metzmacher <metze@samba.org>
Date: Thu, 14 Jun 2012 08:32:43 +0000 (+0200)
Subject: s3:smbd: add a fsp_persistent_id() function
X-Git-Url: http://git.samba.org/?p=ddiss%2Fsamba.git;a=commitdiff_plain;h=cb5a0b1bc311667818ab45bb1837dc67a241a379

s3:smbd: add a fsp_persistent_id() function

This calculates a 64-bit value that most likely uniquely identifies
the files_struct globally to the server.

* 32-bit random gen_id
* 16-bit truncated open_time
* 16-bit fnum (valatile_id)

Based on code from Ira Cooper. Use fsp->fh->gen_id as the persistent
fileid in SMB2.

Pair-Programmed-With: Michael Adam <obnox@samba.org>

metze

Signed-off-by: Jeremy Allison <jra@samba.org>
---

diff --git a/source3/smbd/files.c b/source3/smbd/files.c
index 0018ceed5e5..1031ccfecba 100644
--- a/source3/smbd/files.c
+++ b/source3/smbd/files.c
@@ -566,6 +566,30 @@ files_struct *file_fsp(struct smb_request *req, uint16 fid)
 	return fsp;
 }
 
+uint64_t fsp_persistent_id(const struct files_struct *fsp)
+{
+	uint64_t persistent_id;
+
+	/*
+	 * This calculates a number that is most likely
+	 * globally unique. In future we will have a database
+	 * to make it completely unique.
+	 *
+	 * 32-bit random gen_id
+	 * 16-bit truncated open_time
+	 * 16-bit fnum (valatile_id)
+	 */
+	persistent_id = fsp->fh->gen_id & UINT32_MAX;
+	persistent_id <<= 16;
+	persistent_id &= 0x0000FFFFFFFF0000LLU;
+	persistent_id |= fsp->open_time.tv_usec & UINT16_MAX;
+	persistent_id <<= 16;
+	persistent_id &= 0xFFFFFFFFFFFF0000LLU;
+	persistent_id |= fsp->fnum & UINT16_MAX;
+
+	return persistent_id;
+}
+
 struct files_struct *file_fsp_smb2(struct smbd_smb2_request *smb2req,
 				   uint64_t persistent_id,
 				   uint64_t volatile_id)
diff --git a/source3/smbd/proto.h b/source3/smbd/proto.h
index 929387b2193..d75138b117b 100644
--- a/source3/smbd/proto.h
+++ b/source3/smbd/proto.h
@@ -373,6 +373,7 @@ bool file_find_subpath(files_struct *dir_fsp);
 void file_sync_all(connection_struct *conn);
 void file_free(struct smb_request *req, files_struct *fsp);
 files_struct *file_fsp(struct smb_request *req, uint16 fid);
+uint64_t fsp_persistent_id(const struct files_struct *fsp);
 struct files_struct *file_fsp_smb2(struct smbd_smb2_request *smb2req,
 				   uint64_t persistent_id,
 				   uint64_t volatile_id);