[Libguestfs] [PATCH] added ntfscat_i api

[Richard W.M. Jones]

On Mon, Feb 22, 2016 at 07:23:45PM +0200, noxdafox wrote:
> On 22/02/16 17:26, Richard W.M. Jones wrote:
> >On Sun, Feb 21, 2016 at 11:22:23PM +0200, Matteo Cafasso wrote:
> >>Adding ntfscat_i command for downloading files based on their inode number.
> >>
> >>This allows the dowload of files unaccessible otherwise from a NTFS guest disk image.
> >The patch seems fine, but it really needs a test otherwise this
> >feature could silently break.
> I was thinking the same but I stumbled over an issue which prevented
> me from running the tests.
> I'm not sure this is the right place where to discuss the problem
> but here's few lines about it.
> 
> make  blank-disk.img blank-part.img blank-fs.img blank-bootroot.img
> blank-bootrootlv.img debian.img fedora.img fedora-md1.img
> fedora-md2.img fedora-btrfs.img ubuntu.img archlinux.img coreos.img
> windows.img guests-all-good.xml
> make[3]: Entering directory
> '/home/noxdafox/development/libguestfs/test-data/phony-guests'
> make[3]: 'blank-disk.img' is up to date.
> make[3]: 'blank-part.img' is up to date.
> make[3]: 'blank-fs.img' is up to date.
> make[3]: 'blank-bootroot.img' is up to date.
> make[3]: 'blank-bootrootlv.img' is up to date.
> make[3]: 'debian.img' is up to date.
> rm -f fedora-name.db fedora-name.db-t
> no fedora-name.db-t < fedora-name.db.txt
> /bin/bash: no: command not found

What happens here is it's trying to run ``$(DB_LOAD) fedora-name.db-t''
but the db_load program wasn't found by your configure.  I think you
need to install whatever is the db4-utils (Berkeley DB 4) on your OS.

Alternately you can grab the pre-built databases from a recent
tarball, since we distribute this stuff in the tarball so it doesn't
need to be rebuilt for most end users.

Rich.

> Makefile:1793: recipe for target 'fedora-name.db' failed
> make[3]: *** [fedora-name.db] Error 127
> 
> Searching around it seems some dependency is missing but ./configure
> is not helping me to find which one.
> 
> >
> >Have a look at the tests/ntfsclone/ subdirectory for the general idea.
> This was also another issue, I was not sure ntfs was supported by
> the test suite and I didn't find any documentation about it. I'll
> take a look at these ones.
> >
> >One problem with writing the test (indeed, with the general idea) is
> >how do you discover which inode numbers can be downloaded?  Does NTFS
> >have some standard inode numbers for things like the MFT?
> The $MFT file has alway 0 as index number.
> >
> >Rich.
> >
> >>---
> >>  daemon/ntfs.c        | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
> >>  generator/actions.ml | 15 +++++++++++++
> >>  2 files changed, 77 insertions(+)
> >>
> >>diff --git a/daemon/ntfs.c b/daemon/ntfs.c
> >>index 568899e..58f62fa 100644
> >>--- a/daemon/ntfs.c
> >>+++ b/daemon/ntfs.c
> >>@@ -266,3 +266,65 @@ do_ntfsfix (const char *device, int clearbadsectors)
> >>
> >>    return 0;
> >>  }
> >>+
> >>+int
> >>+do_ntfscat_i (const mountable_t *mountable, int64_t inode)
> >>+{
> >>+  int r;
> >>+  FILE *fp;
> >>+  CLEANUP_FREE char *cmd = NULL;
> >>+  char buffer[GUESTFS_MAX_CHUNK_SIZE];
> >>+
> >>+  /* Inode must be greater than 0 */
> >>+  if (inode < 0) {
> >>+    reply_with_error("Inode must be greater than 0");
> >>+    return -1;
> >>+  }
> >>+
> >>+  /* Construct the command. */
> >>+  if (asprintf_nowarn (&cmd, "ntfscat -i %ld %s",
> >>+                       inode, mountable->device) == -1) {
> >>+    reply_with_perror ("asprintf");
> >>+    return -1;
> >>+  }
> >>+
> >>+  if (verbose)
> >>+    fprintf (stderr, "%s\n", cmd);
> >>+
> >>+  fp = popen (cmd, "r");
> >>+  if (fp == NULL) {
> >>+    reply_with_perror ("%s", cmd);
> >>+    return -1;
> >>+  }
> >>+
> >>+  /* Now we must send the reply message, before the file contents.  After
> >>+   * this there is no opportunity in the protocol to send any error
> >>+   * message back.  Instead we can only cancel the transfer.
> >>+   */
> >>+  reply (NULL, NULL);
> >>+
> >>+  while ((r = fread (buffer, 1, sizeof buffer, fp)) > 0) {
> >>+    if (send_file_write (buffer, r) < 0) {
> >>+      pclose (fp);
> >>+      return -1;
> >>+    }
> >>+  }
> >>+
> >>+  if (ferror (fp)) {
> >>+    fprintf (stderr, "fread: %ld: %m\n", inode);
> >>+    send_file_end (1);		/* Cancel. */
> >>+    pclose (fp);
> >>+    return -1;
> >>+  }
> >>+
> >>+  if (pclose (fp) != 0) {
> >>+    fprintf (stderr, "pclose: %ld: %m\n", inode);
> >>+    send_file_end (1);		/* Cancel. */
> >>+    return -1;
> >>+  }
> >>+
> >>+  if (send_file_end (0))	/* Normal end of file. */
> >>+    return -1;
> >>+
> >>+  return 0;
> >>+}
> >>diff --git a/generator/actions.ml b/generator/actions.ml
> >>index eb45392..18418aa 100644
> >>--- a/generator/actions.ml
> >>+++ b/generator/actions.ml
> >>@@ -12891,6 +12891,21 @@ This is equivalent to C<sgdisk -e>.
> >>
> >>  See also L<sgdisk(8)>." };
> >>
> >>+  { defaults with
> >>+    name = "ntfscat_i"; added = (1, 33, 12);
> >>+    style = RErr, [Mountable "device"; Int64 "inode"; FileOut "filename"], [];
> >>+    proc_nr = Some 463;
> >>+    progress = true; cancellable = true;
> >>+    shortdesc = "download a file to the local machine given its inode";
> >>+    longdesc = "\
> >>+Download a file given its inode from a NTFS filesystem and save it as F<filename>
> >>+on the local machine.
> >>+
> >>+This allows to download some otherwise unaccessible files such as the ones
> >>+within the $Extend folder.
> >>+
> >>+F<filename> can also be a named pipe." };
> >>+
> >>  ]
> >>
> >>  (* Non-API meta-commands available only in guestfish.
> >>--
> >>2.7.0

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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