Added notes to the 'fsck' command documentation.

[libguestfs.git] / src / generator.ml

diff --git a/src/generator.ml b/src/generator.ml
index d680d42..04445ee 100755 (executable)
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -339,8 +339,12 @@ return the default path.");
    "set autosync mode",
    "\
 If C<autosync> is true, this enables autosync.  Libguestfs will make a
-best effort attempt to run C<guestfs_sync> when the handle is closed
-(also if the program exits without closing handles).");
+best effort attempt to run C<guestfs_umount_all> followed by
+C<guestfs_sync> when the handle is closed
+(also if the program exits without closing handles).
+
+This is disabled by default (except in guestfish where it is
+enabled by default).");
 
   ("get_autosync", (RBool "autosync", []), -1, [],
    [],
@@ -1074,6 +1078,20 @@ Some internal mounts are not shown.");
   ("umount_all", (RErr, []), 47, [FishAlias "unmount-all"],
    [InitBasicFS, TestOutputList (
       [["umount_all"];
+       ["mounts"]], []);
+    (* check that umount_all can unmount nested mounts correctly: *)
+    InitEmpty, TestOutputList (
+      [["sfdisk"; "/dev/sda"; "0"; "0"; "0"; ",10 ,20 ,"];
+       ["mkfs"; "ext2"; "/dev/sda1"];
+       ["mkfs"; "ext2"; "/dev/sda2"];
+       ["mkfs"; "ext2"; "/dev/sda3"];
+       ["mount"; "/dev/sda1"; "/"];
+       ["mkdir"; "/mp1"];
+       ["mount"; "/dev/sda2"; "/mp1"];
+       ["mkdir"; "/mp1/mp2"];
+       ["mount"; "/dev/sda3"; "/mp1/mp2"];
+       ["mkdir"; "/mp1/mp2/mp3"];
+       ["umount_all"];
        ["mounts"]], [])],
    "unmount all filesystems",
    "\
@@ -1614,6 +1632,58 @@ to return the existing UUID of a filesystem.");
 This returns the ext2/3/4 filesystem UUID of the filesystem on
 C<device>.");
 
+  ("fsck", (RInt "status", [String "fstype"; String "device"]), 84, [],
+   [InitBasicFS, TestOutputInt (
+      [["umount"; "/dev/sda1"];
+       ["fsck"; "ext2"; "/dev/sda1"]], 0);
+    InitBasicFS, TestOutputInt (
+      [["umount"; "/dev/sda1"];
+       ["zero"; "/dev/sda1"];
+       ["fsck"; "ext2"; "/dev/sda1"]], 8)],
+   "run the filesystem checker",
+   "\
+This runs the filesystem checker (fsck) on C<device> which
+should have filesystem type C<fstype>.
+
+The returned integer is the status.  See L<fsck(8)> for the
+list of status codes from C<fsck>.
+
+Notes:
+
+=over 4
+
+=item *
+
+Multiple status codes can be summed together.
+
+=item *
+
+A non-zero return code can mean \"success\", for example if
+errors have been corrected on the filesystem.
+
+=item *
+
+Checking or repairing NTFS volumes is not supported
+(by linux-ntfs).
+
+=back
+
+This command is entirely equivalent to running C<fsck -a -t fstype device>.");
+
+  ("zero", (RErr, [String "device"]), 85, [],
+   [InitBasicFS, TestOutput (
+      [["umount"; "/dev/sda1"];
+       ["zero"; "/dev/sda1"];
+       ["file"; "/dev/sda1"]], "data")],
+   "write zeroes to the device",
+   "\
+This command writes zeroes over the first few blocks of C<device>.
+
+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.");
+
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
@@ -1804,6 +1874,13 @@ let rec string_split sep str =
     s' :: string_split sep s''
   )
 
+let files_equal n1 n2 =
+  let cmd = sprintf "cmp -s %s %s" (Filename.quote n1) (Filename.quote n2) in
+  match Sys.command cmd with
+  | 0 -> true
+  | 1 -> false
+  | i -> failwithf "%s: failed with error code %d" cmd i
+
 let rec find_map f = function
   | [] -> raise Not_found
   | x :: xs ->
@@ -6227,8 +6304,17 @@ let output_to filename =
   let close () =
     close_out !chan;
     chan := stdout;
-    Unix.rename filename_new filename;
-    printf "written %s\n%!" filename;
+
+    (* Is the new file different from the current file? *)
+    if Sys.file_exists filename && files_equal filename filename_new then
+      Unix.unlink filename_new         (* same, so skip it *)
+    else (
+      (* different, overwrite old one *)
+      (try Unix.chmod filename 0o644 with Unix.Unix_error _ -> ());
+      Unix.rename filename_new filename;
+      Unix.chmod filename 0o444;
+      printf "written %s\n%!" filename;
+    )
   in
   close