[Libguestfs] [PATCH v2 4/5] appliance: Added filesystem_walk command
Pino Toscano
ptoscano at redhat.com
Mon Apr 4 12:04:42 UTC 2016
On Monday 04 April 2016 15:00:26 NoxDaFox wrote:
> 2016-04-04 13:09 GMT+03:00 Pino Toscano <ptoscano at redhat.com>:
>
> > Hi,
> >
> > some of the comments for patch #3 apply also for this one, namely:
> > - wrapping of commit message
> > - indentation of forward declarations
> > - usage of XDR deserialization from guestfs_protocol.h
> > -
> >
> > On Sunday 03 April 2016 16:30:49 Matteo Cafasso wrote:
> > > 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'.
> >
> > As said for patch #3, unknown sizes should be -1 and not 0.
> >
> > > +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));
> >
> > sizeof (*dirents->val) (and below too) can make the code slightly
> > shorter (just an hint).
> >
> > > +
> > > + /* 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));
> >
> > You don't need to shrink the array with values -- users knows already
> > they don't have to access it past 'len' values.
> >
>
> If I then run the command in guestfish I get plenty of empty structs.
Right, that's why setting the right size is the important bit.
I was referring to the realloc which shrinks (or not) the memory of the
array.
--
Pino Toscano
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