New API: set_uuid_random

Signed-off-by: Chen Hanxiao <chenhanxiao@cn.fujitsu.com>

daemon/btrfs.c

@@ -872,6 +872,25 @@ btrfs_set_uuid (const char *device, const char *uuid)
   return 0;
 }
 
+int
+btrfs_set_uuid_random (const char *device)
+{
+  CLEANUP_FREE char *err = NULL;
+  int r;
+  int has_uuid_opts = test_btrfstune_uuid_opt();
+
+  if (has_uuid_opts <= 0)
+    NOT_SUPPORTED(-1, "btrfs filesystems' UUID cannot be changed");
+
+  r = commandr (NULL, &err, str_btrfstune, "-f", "-u", device, NULL);
+  if (r == -1) {
+    reply_with_error ("%s: %s", device, err);
+    return -1;
+  }
+
+  return 0;
+}
+
 /* Takes optional arguments, consult optargs_bitmask. */
 int
 do_btrfs_fsck (const char *device, int64_t superblock, int repair)

daemon/daemon.h

@@ -223,6 +223,7 @@ extern int sync_disks (void);
 /* Confirmed this is true up to ext4 from the Linux sources. */
 #define EXT2_LABEL_MAX 16
 extern int fstype_is_extfs (const char *fstype);
+extern int ext_set_uuid_random (const char *device);
 
 /*-- in blkid.c --*/
 extern char *get_blkid_tag (const char *device, const char *tag);
@@ -265,6 +266,7 @@ extern int copy_xattrs (const char *src, const char *dest);
 /* Documented in xfs_admin(8). */
 #define XFS_LABEL_MAX 12
 extern int xfs_set_uuid (const char *device, const char *uuid);
+extern int xfs_set_uuid_random (const char *device);
 
 /*-- debug-bmap.c --*/
 extern char *debug_bmap (const char *subcmd, size_t argc, char *const *const argv);
@@ -274,6 +276,7 @@ extern char *debug_bmap_device (const char *subcmd, size_t argc, char *const *co
 /*-- in btrfs.c --*/
 extern char *btrfs_get_label (const char *device);
 extern int btrfs_set_uuid (const char *device, const char *uuid);
+extern int btrfs_set_uuid_random (const char *device);
 
 /*-- in ntfs.c --*/
 extern char *ntfs_get_label (const char *device);

daemon/ext2.c

@@ -159,6 +159,12 @@ do_set_e2uuid (const char *device, const char *uuid)
   return 0;
 }
 
+int
+ext_set_uuid_random (const char *device)
+{
+  return do_set_e2uuid (device, "random");
+}
+
 char *
 do_get_e2uuid (const char *device)
 {

daemon/uuids.c

@@ -85,3 +85,35 @@ do_set_uuid (const char *device, const char *uuid)
 
   return r;
 }
+
+int
+do_set_uuid_random (const char *device)
+{
+  int r;
+
+  /* How we set the UUID depends on the filesystem type. */
+  CLEANUP_FREE char *vfs_type = get_blkid_tag (device, "TYPE");
+  if (vfs_type == NULL)
+    return -1;
+
+  CLEANUP_FREE char *uuid_random = get_random_uuid ();
+  if (uuid_random == NULL)
+    return -1;
+
+  if (fstype_is_extfs (vfs_type))
+    r = ext_set_uuid_random (device);
+
+  else if (STREQ (vfs_type, "xfs"))
+    r = xfs_set_uuid_random (device);
+
+  else if (STREQ (vfs_type, "swap"))
+    r = swap_set_uuid (device, uuid_random);
+
+  else if (STREQ (vfs_type, "btrfs"))
+    r = btrfs_set_uuid_random (device);
+
+  else
+    NOT_SUPPORTED(-1, "don't know how to set the random UUID for '%s' filesystems",
+                      vfs_type);
+  return r;
+}

daemon/xfs.c

@@ -462,6 +462,13 @@ xfs_set_uuid (const char *device, const char *uuid)
   return do_xfs_admin (device, 0, 0, 0, 0, 0, NULL, uuid);
 }
 
+int
+xfs_set_uuid_random (const char *device)
+{
+  optargs_bitmask = GUESTFS_XFS_ADMIN_UUID_BITMASK;
+  return do_xfs_admin (device, 0, 0, 0, 0, 0, NULL, "generate");
+}
+
 int
 do_xfs_admin (const char *device,
               int extunwritten, int imgfile, int v2log,

generator/actions.ml

@@ -12636,6 +12636,25 @@ removed from the filesystem.
 The C<targetdev> needs to be same size or larger than the C<srcdev>. Devices
 which are currently mounted are never allowed to be used as the C<targetdev>." };
 
+  { defaults with
+    name = "set_uuid_random"; added = (1, 29, 50);
+    style = RErr, [Device "device"], [];
+    proc_nr = Some 456;
+    tests = [
+        InitBasicFS, Always, TestRun (
+            [["set_uuid_random"; "/dev/sda1"]]), [];
+      ];
+    shortdesc = "set a random UUID for the filesystem";
+    longdesc = "\
+Set the filesystem UUID on C<device> to a random UUID.
+If this fails and the errno is ENOTSUP,
+means that there is no support for changing the UUID
+for the type of the specified filesystem.
+
+Only some filesystem types support setting UUIDs.
+
+To read the UUID on a filesystem, call C<guestfs_vfs_uuid>." };
+
 ]
 
 (* Non-API meta-commands available only in guestfish.

src/MAX_PROC_NR

@@ -1 +1 @@
-455
+456

tests/btrfs/test-btrfs-misc.pl

@@ -67,5 +67,19 @@ if ($@) {
     unless $uuid eq "12345678-1234-1234-1234-123456789012";
 }
 
+# Setting btrfs random UUID.
+eval {
+    $g->set_uuid_random ("/dev/sda1")
+};
+
+if ($@) {
+    my $err = $g->last_errno ();
+    if ($err == Errno::ENOTSUP()) {
+        warn "$0: skipping test for btrfs UUID change feature is not available";
+    } else {
+        die $@;
+    }
+}
+
 $g->shutdown ();
 $g->close ();