New APIs: is-zero and is-zero-device, to test if file or device is all zeroes.

[libguestfs.git] / generator / generator_actions.ml

diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 9c5aefd..d0aac87 100644 (file)
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -2268,15 +2268,12 @@ The exact command which runs is C<file -zb path>.  Note in
 particular that the filename is not prepended to the output
 (the I<-b> option).
 
 particular that the filename is not prepended to the output
 (the I<-b> option).
 

-This command can also be used on C</dev/> devices
-(and partitions, LV names).  You can for example use this
-to determine if a device contains a filesystem, although
-it's usually better to use C<guestfs_vfs_type>.
+The output depends on the output of the underlying L<file(1)>
+command and it can change in future in ways beyond our control.
+In other words, the output is not guaranteed by the ABI.

 
 

-If the C<path> does not begin with C</dev/> then
-this command only works for the content of regular files.
-For other file types (directory, symbolic link etc) it
-will just return the string C<directory> etc.");
+See also: L<file(1)>, C<guestfs_vfs_type>, C<guestfs_lstat>,
+C<guestfs_is_file>, C<guestfs_is_blockdev> (etc), C<guestfs_is_zero>.");

 
   ("command", (RString "output", [StringList "arguments"], []), 50, [ProtocolLimitWarning],
    [InitScratchFS, Always, TestOutput (
 
   ("command", (RString "output", [StringList "arguments"], []), 50, [ProtocolLimitWarning],
    [InitScratchFS, Always, TestOutput (


@@ -2982,7 +2979,8 @@ How many blocks are zeroed isn't specified (but it's I<not> enough
 to securely wipe the device).  It should be sufficient to remove
 any partition tables, filesystem superblocks and so on.
 
 to securely wipe the device).  It should be sufficient to remove
 any partition tables, filesystem superblocks and so on.
 

-See also: C<guestfs_zero_device>, C<guestfs_scrub_device>.");
+See also: C<guestfs_zero_device>, C<guestfs_scrub_device>,
+C<guestfs_is_zero_device>");

 
   ("grub_install", (RErr, [Pathname "root"; Device "device"], []), 86, [],
    (* See:
 
   ("grub_install", (RErr, [Pathname "root"; Device "device"], []), 86, [],
    (* See:


@@ -5940,6 +5938,29 @@ Instead, use the autosync flag (C<guestfs_set_autosync>) to
 control whether or not this operation is performed when the
 handle is closed.");
 
 control whether or not this operation is performed when the
 handle is closed.");
 

+  ("is_zero", (RBool "zeroflag", [Pathname "path"], []), 283, [],
+   [InitISOFS, Always, TestOutputTrue (
+      [["is_zero"; "/100kallzeroes"]]);
+    InitISOFS, Always, TestOutputFalse (
+      [["is_zero"; "/100kallspaces"]])],
+   "test if a file contains all zero bytes",
+   "\
+This returns true iff the file exists and the file is empty or
+it contains all zero bytes.");
+
+  ("is_zero_device", (RBool "zeroflag", [Device "device"], []), 284, [],
+   [InitBasicFS, Always, TestOutputTrue (
+      [["umount"; "/dev/sda1"];
+       ["zero_device"; "/dev/sda1"];
+       ["is_zero_device"; "/dev/sda1"]]);
+    InitBasicFS, Always, TestOutputFalse (
+      [["is_zero_device"; "/dev/sda1"]])],
+   "test if a device contains all zero bytes",
+   "\
+This returns true iff the device exists and contains all zero bytes.
+
+Note that for large devices this can take a long time to run.");
+

 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions