[Libguestfs] [PATCH v2 4/5] appliance: Added filesystem_walk command

Matteo Cafasso
2016-04-03T13:30:49Z

The filesystem_walk command is the appliance's
counterpart of the daemon's
internal_filesystem_walk 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_filesystem_walk command.

Signed-off-by: Matteo Cafasso <noxdafox at gmail.com>
---
 generator/actions.ml |  69 ++++++++++++++++++++++
 src/Makefile.am      |   1 +
 src/tsk.c            | 162 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+)
 create mode 100644 src/tsk.c

diff --git a/generator/actions.ml b/generator/actions.ml
index 449ffa0..9457c3f 100644
--- a/generator/actions.ml
+++ b/generator/actions.ml
@@ -3546,6 +3546,75 @@ The environment variable C<XDG_RUNTIME_DIR>
controls the default
 value: If C<XDG_RUNTIME_DIR> is set, then that is the default.
 Else F</tmp> is the default." };

+  { defaults with
+    name = "filesystem_walk"; added = (1, 33, 17);
+    style = RStructList ("dirents", "tsk_dirent"),
[Mountable "device";], [];
+    optional = Some "libtsk";
+    progress = true; cancellable = true;
+    shortdesc = "walk through the filesystem content";
+    longdesc = "\
+Walk through the internal structures of a disk partition
+(eg. F</dev/sda1>) in order to return a list of all the files
+and directories stored within.
+
+It is not necessary to mount the disk partition to run this command.
+
+All entries in the filesystem are returned, excluding C<.> and
+C<..>. This function can list deleted or unaccessible files.
+The entries are I<not> sorted.
+
+If the entry is not allocated (ex: it has been deleted),
+its inode, type or size might not be recovered correctly.
+In such case, the inode and the size will be 0 while the type
+will be unidentified 'u'.
+
+This call returns as well basic file type information about each
+file.  The C<tsk_type> field will contain one of the following
characters:
+
+=over 4
+
+=item 'b'
+
+Block special
+
+=item 'c'
+
+Char special
+
+=item 'd'
+
+Directory
+
+=item 'f'
+
+FIFO (named pipe)
+
+=item 'l'
+
+Symbolic link
+
+=item 'r'
+
+Regular file
+
+=item 's'
+
+Socket
+
+=item 'h'
+
+Shadow inode (Solaris)
+
+=item 'w'
+
+Whiteout inode (BSD)
+
+=item 'u'
+
+Unknown file type
+
+=back" };
+
 ]

 (* daemon_functions are any functions which cause some action
diff --git a/src/Makefile.am b/src/Makefile.am
index 3b4cd10..9f8af4c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -130,6 +130,7 @@ libguestfs_la_SOURCES = \
 	structs-copy.c \
 	structs-free.c \
 	tmpdirs.c \
+	tsk.c \
 	whole-file.c \
 	libguestfs.syms

diff --git a/src/tsk.c b/src/tsk.c
new file mode 100644
index 0000000..d77bc0a
--- /dev/null
+++ b/src/tsk.c
@@ -0,0 +1,162 @@
+/* libguestfs
+ * Copyright (C) 2016 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <string.h>
+#include <rpc/xdr.h>
+#include <rpc/types.h>
+
+#include "full-read.h"
+
+#include "guestfs.h"
+#include "guestfs_protocol.h"
+#include "guestfs-internal.h"
+#include "guestfs-internal-all.h"
+#include "guestfs-internal-actions.h"
+
+static struct guestfs_tsk_dirent_list *parse_filesystem_walk
+(guestfs_h *g, char *buf, size_t bufsize);
+int deserialise_dirent_list (guestfs_h *g, char *buf, size_t bufsize,
+                             struct guestfs_tsk_dirent_list **dirents);
+static int deserialise_dirent (guestfs_h *g, XDR *xdrs,
+                               struct guestfs_tsk_dirent *dirent);
+
+struct guestfs_tsk_dirent_list *
+guestfs_impl_filesystem_walk (guestfs_h *g, const char *mountable)
+{
+  int ret = 0;
+  size_t size = 0;
+  CLEANUP_FREE char *buf = NULL;
+  CLEANUP_UNLINK_FREE char *tmpfile = NULL;
+
+  ret = guestfs_int_lazy_make_tmpdir (g);
+  if (ret < 0)
+    return NULL;
+
+  tmpfile = safe_asprintf (g, "%s/filesystem_walk%d", g->tmpdir,
++g->unique);
+
+  ret = guestfs_internal_filesystem_walk (g, mountable, tmpfile);
+  if (ret < 0)
+    return NULL;
+
+  ret = guestfs_int_read_whole_file (g, tmpfile, &buf, &size);
+  if (ret < 0)
+    return NULL;
+
+  return parse_filesystem_walk (g, buf, size);  /* caller frees */
+}
+
+/* Parse buf content and return dirents list.
+ * Return a list of tsk_dirent on success, NULL on error.
+ */
+static struct guestfs_tsk_dirent_list *
+parse_filesystem_walk (guestfs_h *g, char *buf, size_t bufsize)
+{
+  int ret = 0;
+  struct guestfs_tsk_dirent_list *dirents = NULL;
+
+  /* Initialise results array. */
+  dirents = safe_malloc (g, sizeof (struct guestfs_tsk_dirent_list));
+  dirents->len = 8;
+  dirents->val = safe_malloc (g, dirents->len *
+                              sizeof (struct guestfs_tsk_dirent));
+
+  /* Deserialise buffer into dirent list. */
+  ret = deserialise_dirent_list (g, buf, bufsize, &dirents);
+  if (ret < 0) {
+    guestfs_free_tsk_dirent_list (dirents);
+    return NULL;
+  }
+
+  /* Resize the array to correct number of entries. */
+  dirents->len = ret;
+  dirents->val = safe_realloc (g, dirents->val,
+                               dirents->len *
+                               sizeof (struct guestfs_tsk_dirent));
+
+  return dirents;
+}
+
+/* Deserialise buf content and populate the dirent list.
+ * Return the number of deserialised dirents, -1 on error.
+ */
+int
+deserialise_dirent_list (guestfs_h *g, char *buf, size_t bufsize,
+                         struct guestfs_tsk_dirent_list **dirents)
+{
+  XDR xdr;
+  int ret = 0;
+  uint32_t index = 0;
+
+  xdrmem_create (&xdr, buf, bufsize, XDR_DECODE);
+
+  for (index = 0; xdr_getpos (&xdr) < bufsize; index++) {
+    if (index == (*dirents)->len) {
+      (*dirents)->len = 2 * (*dirents)->len;
+      (*dirents)->val = safe_realloc (g, (*dirents)->val,
+                                      (*dirents)->len *
+                                      sizeof (struct guestfs_tsk_dirent));
+    }
+
+    ret = deserialise_dirent (g, &xdr, &(*dirents)->val[index]);
+    if (ret < 0)
+      break;
+  }
+
+  xdr_destroy (&xdr);
+
+  return index;
+}
+
+/* Parse a single XDR encoded tsk_dirent.
+ * Return 0 on success, -1 on error.
+ */
+static int
+deserialise_dirent (guestfs_h *g, XDR *xdrs, struct guestfs_tsk_dirent *dirent)
+{
+  size_t len = 0;
+  CLEANUP_FREE char *buf = NULL;
+
+  /* Deserialise tsk_dirent struct. */
+  if (!xdr_uint64_t (xdrs, &dirent->tsk_inode))
+    return -1;
+  if (!xdr_char (xdrs, &dirent->tsk_type))
+    return -1;
+  if (!xdr_int64_t (xdrs, &dirent->tsk_size))
+    return -1;
+
+  /* Deserialise filename. */
+  if (!xdr_u_long (xdrs, &len))
+    return -1;
+  buf = safe_malloc (g, len);
+  if (!xdr_string (xdrs, &buf, len))
+    return -1;
+  dirent->tsk_name = safe_strndup(g, buf, len);
+
+  if (!xdr_uint32_t (xdrs, &dirent->tsk_allocated))
+    return -1;
+
+  return 0;
+}
--
2.8.0.rc3