New API: guestfs_copy_size to copy a fixed number of bytes.

This is similar to 'guestfs_dd', but it copies just a fixed
number of bytes from the source to the destination.  It's an
error if the source is too short or if the destination is too
small.

2 files changed, 15 insertions, 2 deletions

diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index f4146713..2c36bbda 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-226
+227
diff --git a/src/generator.ml b/src/generator.ml
index 551b6bc6..5f5b4370 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -4240,7 +4240,7 @@ example to duplicate a filesystem.
 
 If the destination is a device, it must be as large or larger
 than the source file or device, otherwise the copy will fail.
-This command cannot do partial copies.");
+This command cannot do partial copies (see C<guestfs_copy_size>).");
 
   ("filesize", (RInt64 "size", [Pathname "file"]), 218, [],
    [InitBasicFS, Always, TestOutputInt (
@@ -4333,6 +4333,19 @@ calls to associate logical volumes and volume groups.
 
 See also C<guestfs_vgpvuuids>.");
 
+  ("copy_size", (RErr, [Dev_or_Path "src"; Dev_or_Path "dest"; Int64 "size"]), 227, [],
+   [InitBasicFS, Always, TestOutputBuffer (
+      [["write_file"; "/src"; "hello, world"; "0"];
+       ["copy_size"; "/src"; "/dest"; "5"];
+       ["read_file"; "/dest"]], "hello")],
+   "copy size bytes from source to destination using dd",
+   "\
+This command copies exactly C<size> bytes from one source device
+or file C<src> to another destination device or file C<dest>.
+
+Note this will fail if the source is too short or if the destination
+is not large enough.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions