From 22e531bc459309d9a871a845cfacd1396ff5b7e4 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones@redhat.com>
Date: Sun, 22 Nov 2009 19:15:56 +0000
Subject: [PATCH] Implement 'dd' command.

---
 TODO               |  1 -
 daemon/Makefile.am |  1 +
 daemon/dd.c        | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 guestfs.pod        | 35 +++++++++++++++++++++++++++
 po/POTFILES.in     |  1 +
 src/MAX_PROC_NR    |  2 +-
 src/generator.ml   | 16 ++++++++++++
 7 files changed, 125 insertions(+), 2 deletions(-)
 create mode 100644 daemon/dd.c

diff --git a/TODO b/TODO
index 24c0171..661c137 100644
--- a/TODO
+++ b/TODO
@@ -127,7 +127,6 @@ Ideas for extra commands
 
   General glibc / core programs:
     chgrp
-    dd (?)
     more mk*temp calls
 
   ext2 properties:
diff --git a/daemon/Makefile.am b/daemon/Makefile.am
index 7034bbf..75867cb 100644
--- a/daemon/Makefile.am
+++ b/daemon/Makefile.am
@@ -51,6 +51,7 @@ guestfsd_SOURCES = \
 	command.c \
 	cpmv.c \
 	daemon.h \
+	dd.c \
 	debug.c \
 	devsparts.c \
 	df.c \
diff --git a/daemon/dd.c b/daemon/dd.c
new file mode 100644
index 0000000..2402e13
--- /dev/null
+++ b/daemon/dd.c
@@ -0,0 +1,71 @@
+/* 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 "../src/guestfs_protocol.h"
+#include "daemon.h"
+#include "actions.h"
+
+int
+do_dd (const char *src, const char *dest)
+{
+  int src_is_dev, dest_is_dev;
+  char *if_arg, *of_arg;
+  char *err;
+  int r;
+
+  src_is_dev = STRPREFIX (src, "/dev/");
+
+  if (src_is_dev)
+    r = asprintf (&if_arg, "if=%s", src);
+  else
+    r = asprintf (&if_arg, "if=%s%s", sysroot, src);
+  if (r == -1) {
+    reply_with_perror ("asprintf");
+    return -1;
+  }
+
+  dest_is_dev = STRPREFIX (dest, "/dev/");
+
+  if (dest_is_dev)
+    r = asprintf (&of_arg, "of=%s", dest);
+  else
+    r = asprintf (&of_arg, "of=%s%s", sysroot, dest);
+  if (r == -1) {
+    reply_with_perror ("asprintf");
+    free (if_arg);
+    return -1;
+  }
+
+  r = command (NULL, &err, "dd", "bs=1024K", if_arg, of_arg, NULL);
+  free (if_arg);
+  free (of_arg);
+
+  if (r == -1) {
+    reply_with_error ("dd: %s: %s: %s", src, dest, err);
+    free (err);
+    return -1;
+  }
+  free (err);
+
+  return 0;
+}
diff --git a/guestfs.pod b/guestfs.pod
index 4a47733..7b6a34e 100644
--- a/guestfs.pod
+++ b/guestfs.pod
@@ -274,6 +274,41 @@ non-portable between kernel versions, and they don't support labels or
 UUIDs.  If you want to pre-build an image or you need to mount it
 using a label or UUID, use an ISO image instead.
 
+=head2 COPYING
+
+There are various different commands for copying between files and
+devices and in and out of the guest filesystem.  These are summarised
+in the table below.
+
+=over 4
+
+=item B<file> to B<file>
+
+Use L</guestfs_cp> to copy a single file, or
+L</guestfs_cp_a> to copy directories recursively.
+
+=item B<file or device> to B<file or device>
+
+Use L</guestfs_dd> which efficiently uses L<dd(1)>
+to copy between files and devices in the guest.
+
+Example: duplicate the contents of an LV:
+
+ guestfs_dd (g, "/dev/VG/Original", "/dev/VG/Copy");
+
+The destination (C</dev/VG/Copy>) must be at least as large as the
+source (C</dev/VG/Original>).
+
+=item B<file on the host> to B<file or device>
+
+Use L</guestfs_upload>.  See L</UPLOADING> above.
+
+=item B<file or device> to B<file on the host>
+
+Use L</guestfs_download>.  See L</DOWNLOADING> above.
+
+=back
+
 =head2 LISTING FILES
 
 C<guestfs_ll> is just designed for humans to read (mainly when using
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 7707811..afaa33b 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -6,6 +6,7 @@ daemon/checksum.c
 daemon/cmp.c
 daemon/command.c
 daemon/cpmv.c
+daemon/dd.c
 daemon/debug.c
 daemon/devsparts.c
 daemon/df.c
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index a817176..0ddd619 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-216
+217
diff --git a/src/generator.ml b/src/generator.ml
index 1c533fa..a7135a7 100755
--- a/src/generator.ml
+++ b/src/generator.ml
@@ -4162,6 +4162,22 @@ See also C<guestfs_version>.
 
 =back");
 
+  ("dd", (RErr, [Dev_or_Path "src"; Dev_or_Path "dest"]), 217, [],
+   [InitBasicFS, Always, TestOutputBuffer (
+      [["write_file"; "/src"; "hello, world"; "0"];
+       ["dd"; "/src"; "/dest"];
+       ["read_file"; "/dest"]], "hello, world")],
+   "copy from source to destination using dd",
+   "\
+This command copies from one source device or file C<src>
+to another destination device or file C<dest>.  Normally you
+would use this to copy to or from a device or partition, for
+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.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
-- 
1.8.3.1