[Xen-devel] [PATCH 6 of 9 RFC v2] blktap3/libblktapctl: Introduce block device control information retrieval functionality

[Thanos Makatos <thanos.makatos@xxxxxxxxxx>]

This patch introduces function tap_ctl_info. It is used by the tapback daemon
to retrieve the size of the block device, as well as the sector size,  in order
to communicate it to blkfront so that it can create the virtual block device.

diff --git a/tools/blktap3/control/tap-ctl-info.c 
b/tools/blktap3/control/tap-ctl-info.c
new file mode 100644
--- /dev/null
+++ b/tools/blktap3/control/tap-ctl-info.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2012      Citrix Ltd.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA.
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include "tap-ctl.h"
+#include "tap-ctl-info.h"
+
+int tap_ctl_info(pid_t pid, int minor, unsigned long long *sectors,
+        unsigned int *sector_size, unsigned int *info)
+{
+    tapdisk_message_t message;
+    int err;
+
+    memset(&message, 0, sizeof(message));
+    message.type = TAPDISK_MESSAGE_DISK_INFO;
+    message.cookie = minor;
+
+    err = tap_ctl_connect_send_and_receive(pid, &message, NULL);
+    if (err)
+        return err;
+
+    if (message.type != TAPDISK_MESSAGE_DISK_INFO_RSP)
+        return -EINVAL;
+
+    *sectors = message.u.image.sectors;
+    *sector_size = message.u.image.sector_size;
+    *info = message.u.image.info;
+    return err;
+}
diff --git a/tools/blktap3/control/tap-ctl-info.h 
b/tools/blktap3/control/tap-ctl-info.h
new file mode 100644
--- /dev/null
+++ b/tools/blktap3/control/tap-ctl-info.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2012      Citrix Ltd.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA.
+ */
+
+#ifndef __TAP_CTL_INFO_H__
+#define __TAP_CTL_INFO_H__
+
+/**
+ * Retrieves virtual disk information from a tapdisk.
+ *
+ * @pid the process ID of the tapdisk process
+ * @minor the minor device number
+ * @sectors output parameter that receives the number of sectors
+ * @sector_size output parameter that receives the size of the sector
+ * @info TODO ?
+ * 
+ */
+int tap_ctl_info(pid_t pid, int minor, unsigned long long *sectors,
+        unsigned int *sector_size, unsigned int *info);
+
+#endif /* __TAP_CTL_INFO_H__ */

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel