[Libguestfs] [PATCH 2/4] New API: find_block

[Matteo Cafasso]

Library's counterpart of the daemon's internal_find_block command.

It writes the daemon's command output on a temporary file and parses it,
deserialising the XDR formatted tsk_dirent structs.

It returns to the caller the list of tsk_dirent structs generated by the
internal_find_block command.

Signed-off-by: Matteo Cafasso <noxdafox at gmail.com>
---
 generator/actions.ml | 16 ++++++++++++++++
 src/tsk.c            | 26 ++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/generator/actions.ml b/generator/actions.ml
index b38a30f..8947551 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -3729,6 +3729,22 @@ Searches all the entries associated with the given inode.
 For each entry, a C<tsk_dirent> structure is returned.
 See C<filesystem_walk> for more information about C<tsk_dirent> structures." };

+  { defaults with
+    name = "find_block"; added = (1, 35, 6);
+    style = RStructList ("dirents", "tsk_dirent"), [Mountable "device"; Int64 "block";], [];
+    optional = Some "libtsk";
+    progress = true; cancellable = true;
+    shortdesc = "search the entries referring to the given data block";
+    longdesc = "\
+Searches all the entries referring to the given data block.
+
+Certain filesystems preserve the block mapping when deleting a file.
+Therefore, it is possible to see multiple deleted files referring
+to the same block.
+
+For each entry, a C<tsk_dirent> structure is returned.
+See C<filesystem_walk> for more information about C<tsk_dirent> structures." };
+
 ]

 (* daemon_functions are any functions which cause some action
diff --git a/src/tsk.c b/src/tsk.c
index d3da834..6b1b29c 100644
--- a/src/tsk.c
+++ b/src/tsk.c
@@ -89,6 +89,32 @@ guestfs_impl_find_inode (guestfs_h *g, const char *mountable, int64_t inode)
   return parse_dirent_file (g, fp);  /* caller frees */
 }

+struct guestfs_tsk_dirent_list *
+guestfs_impl_find_block (guestfs_h *g, const char *mountable, int64_t block)
+{
+  int ret = 0;
+  CLEANUP_FCLOSE FILE *fp = NULL;
+  CLEANUP_UNLINK_FREE char *tmpfile = NULL;
+
+  ret = guestfs_int_lazy_make_tmpdir (g);
+  if (ret < 0)
+    return NULL;
+
+  tmpfile = safe_asprintf (g, "%s/find_block%d", g->tmpdir, ++g->unique);
+
+  ret = guestfs_internal_find_block (g, mountable, block, tmpfile);
+  if (ret < 0)
+    return NULL;
+
+  fp = fopen (tmpfile, "r");
+  if (fp == NULL) {
+    perrorf (g, "fopen: %s", tmpfile);
+    return NULL;
+  }
+
+  return parse_dirent_file (g, fp);  /* caller frees */
+}
+
 /* Parse the file content and return dirents list.
  * Return a list of tsk_dirent on success, NULL on error.
  */
--
2.9.3