[Libguestfs] [PATCH] New API: vfs_type - get the Linux VFS driver for a mounted device

[Richard W.M. Jones]

After much discussion on IRC we thought it's better not to make this
so specific to 'blkid', but to make it a general call to return the
VFS type.  Here is an updated patch.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v
-------------- next part --------------
>From d609130cb65fe7795b168a796426e39d64ceda97 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones at redhat.com>
Date: Mon, 26 Oct 2009 14:26:36 +0000
Subject: [PATCH] New API: vfs_type - get the Linux VFS driver for a mounted device.

---
 daemon/Makefile.am |    1 +
 daemon/blkid.c     |   53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 po/POTFILES.in     |    1 +
 src/MAX_PROC_NR    |    2 +-
 src/generator.ml   |   12 +++++++++++
 5 files changed, 68 insertions(+), 1 deletions(-)
 create mode 100644 daemon/blkid.c

diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index ae74699..dce868a 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -23,6 +23,7 @@ noinst_PROGRAMS = guestfsd
 guestfsd_SOURCES = \
 	actions.h \
 	augeas.c \
+	blkid.c \
 	blockdev.c \
 	checksum.c \
 	cmp.c \
diff --git a/daemon/blkid.c b/daemon/blkid.c
new file mode 100644
index 0000000..4e14881
--- /dev/null
+++ b/daemon/blkid.c
@@ -0,0 +1,53 @@
+/* libguestfs - the guestfsd daemon
+ * Copyright (C) 2009 Red Hat Inc.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "daemon.h"
+#include "actions.h"
+
+char *
+do_vfs_type (const char *device)
+{
+  char *out, *err;
+  int r;
+
+  r = command (&out, &err,
+               "/sbin/blkid", "-o", "value", "-s", "TYPE", device, NULL);
+  if (r == -1) {
+    reply_with_error ("vfs_type: %s: %s", device, err);
+    free (out);
+    free (err);
+    return NULL;
+  }
+
+  free (err);
+
+  /* Trim trailing \n if present. */
+  size_t len = strlen (out);
+  if (len > 0 && out[len-1] == '\n')
+    out[len-1] = '\0';
+
+  return out;                   /* caller frees */
+}
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 57cce91..a70072b 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -1,4 +1,5 @@
 daemon/augeas.c
+daemon/blkid.c
 daemon/blockdev.c
 daemon/checksum.c
 daemon/cmp.c
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index 5381652..ca55a6c 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-197
+198
diff --git a/src/generator.ml b/src/generator.ml
index f634cc8..4e056e2 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -3703,6 +3703,18 @@ This function does not handle drive names, backslashes etc.
 
 See also C<guestfs_realpath>.");
 
+  ("vfs_type", (RString "fstype", [Device "device"]), 198, [],
+   [InitBasicFS, Always, TestOutput (
+      [["vfs_type"; "/dev/sda1"]], "ext2")],
+   "get the Linux VFS type corresponding to a mounted device",
+   "\
+This command gets the block device type corresponding to
+a mounted device called C<device>.
+
+Usually the result is the name of the Linux VFS module that
+is used to mount this device (probably determined automatically
+if you used the C<guestfs_mount> call).");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
-- 
1.6.5.rc2