[Libguestfs] [PATCH 1/2] added filesystem_walk API
Pino Toscano
ptoscano at redhat.com
Wed Mar 30 09:29:21 UTC 2016
On Tuesday 29 March 2016 20:42:48 Matteo Cafasso wrote:
> Signed-off-by: Matteo Cafasso <noxdafox at gmail.com>
> ---
See general notes sent as
https://www.redhat.com/archives/libguestfs/2016-March/msg00269.html
> generator/actions.ml | 13 ++++
> src/Makefile.am | 1 +
> src/tsk.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 208 insertions(+)
> create mode 100644 src/tsk.c
>
> diff --git a/generator/actions.ml b/generator/actions.ml
> index e33655a..f795721 100644
> --- a/generator/actions.ml
> +++ b/generator/actions.ml
> @@ -3546,6 +3546,19 @@ 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, 16);
1.33.17 now.
> + style = RStructList ("nodeinfos", "tsk_node"), [Mountable "device";], [];
This patch lacks the addition of tsk_node to generator/structs.ml.
> + 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.
> +
> +For each file or directory found, the function reports its path, its inode and whether
> +it is allocated or not." };
> +
> ]
>
> (* 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..551b615
> --- /dev/null
> +++ b/src/tsk.c
> @@ -0,0 +1,194 @@
> +/* 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 "full-write.h"
full-write.h is not needed.
> +
> +#include "guestfs.h"
> +#include "guestfs_protocol.h"
> +#include "guestfs-internal.h"
> +#include "guestfs-internal-all.h"
> +#include "guestfs-internal-actions.h"
> +
> +#ifdef HAVE_LIBTSK
Considering this file does not really need libtsk, just always compile
the whole content of it; otherwise, building libguestfs without libtsk
will result in undefined references to guestfs_impl_filesystem_walk
when linking libguestfs.so (since it wouldn't be defined at all).
> +static int deserialise_inode_info
> +(guestfs_h *g, XDR *xdrs, struct guestfs_tsk_node *node_info);
> +static size_t read_file(guestfs_h *g, const char *path, char **dest);
> +static struct guestfs_tsk_node_list *
> +parse_filesystem_walk0 (guestfs_h *g, char *buf, size_t bufsize);
> +static void free_nodes(struct guestfs_tsk_node_list *nodes);
> +
> +struct guestfs_tsk_node_list *
> +guestfs_impl_filesystem_walk(guestfs_h *g, const char *mountable)
> +{
> + size_t size = 0;
> +
> + CLEANUP_FREE char *buf = NULL;
> + CLEANUP_UNLINK_FREE char *tmpfile = NULL;
> +
> + if (guestfs_int_lazy_make_tmpdir (g) == -1)
> + return NULL;
> +
> + tmpfile = safe_asprintf(g, "%s/filesystem_walk%d", g->tmpdir, ++g->unique);
> +
> + if (guestfs_filesystem_walk0(g, mountable, tmpfile) < 0)
> + return NULL;
> +
> + if (!(size = read_file(g, tmpfile, &buf)))
> + return NULL;
> +
> + return parse_filesystem_walk0(g, buf, size); /* caller frees */
> +}
> +
> +/* Read the whole file at path into dest.
> + * Return the size of the file, 0 on error.
> + */
> +static size_t read_file(guestfs_h *g, const char *path, char **dest)
We have already guestfs_int_read_whole_file for this, see whole-file.c.
> +{
> + int fd = 0;
> + size_t size;
> + struct stat statbuf;
> +
> + if ((fd = open(path, O_RDONLY|O_CLOEXEC)) == -1) {
> + perrorf(g, "open: %s", path);
> + return 0;
> + }
> +
> + if (fstat(fd, &statbuf) == -1) {
> + perrorf(g, "stat: %s", path);
> + close(fd);
> + return 0;
> + }
> +
> + size = statbuf.st_size;
> + if (!(*dest = malloc(size))) {
> + perrorf(g, "malloc: %zu bytes", size);
> + close(fd);
> + return 0;
> + }
> +
> + if (full_read(fd, *dest, size) != size) {
> + perrorf(g, "full-read: %s: %zu bytes", path, size);
> + close(fd);
> + return 0;
> + }
> +
> + if (close(fd) == -1) {
> + perrorf(g, "close: %s", path);
> + close(fd);
> + return 0;
> + }
> +
> + return size;
> +}
> +
> +/* Parse buf content and populate nodes list.
> + * Return a list of tsk_nodes on success, NULL on error.
> + */
> +static struct guestfs_tsk_node_list *
> +parse_filesystem_walk0 (guestfs_h *g, char *buf, size_t bufsize)
> +{
> + XDR xdr;
> + uint32_t index = 0;
> + struct guestfs_tsk_node_list *nodes = NULL;
> +
> + nodes = safe_malloc(g, sizeof *nodes);
> + nodes->len = 0;
> + nodes->val = NULL;
> +
> + xdrmem_create(&xdr, buf, bufsize, XDR_DECODE);
> +
> + for (index = 0; xdr_getpos(&xdr) < bufsize; index++) {
> + if (index == nodes->len) {
> + nodes->len = 2 * (nodes->len + 1);
Why +1 here?
> + nodes->val = safe_realloc(g, nodes->val,
> + nodes->len * sizeof (struct guestfs_tsk_node));
> + }
> +
> + if (deserialise_inode_info(g, &xdr, &nodes->val[index]) < 0)
> + {
> + xdr_destroy(&xdr);
> + free_nodes(nodes);
> +
> + return NULL;
> + }
> + }
> +
> + xdr_destroy(&xdr);
> +
> + nodes->len = index;
> + nodes->val = safe_realloc(g, nodes->val,
> + nodes->len * sizeof (struct guestfs_tsk_node));
What is this for?
> +
> + return nodes;
> +}
> +
> +/* Parse a single XDR encoded node_info.
> + * Return 0 on success, -1 on error.
> + */
> +static int
> +deserialise_inode_info
> +(guestfs_h *g, XDR *xdrs, struct guestfs_tsk_node *node_info)
> +{
> + size_t len = 0;
> + CLEANUP_FREE char *buf = NULL;
> +
> + if (!xdr_u_long(xdrs, &len))
> + return -1;
> +
> + buf = safe_malloc(g, len);
> +
> + if (!xdr_string(xdrs, &buf, len))
> + return -1;
> + if (!xdr_uint64_t(xdrs, &node_info->tsk_inode))
> + return -1;
> + if (!xdr_uint32_t(xdrs, &node_info->tsk_allocated))
> + return -1;
> +
> + node_info->tsk_name = safe_strndup(g, buf, len);
> +
> + return 0;
> +}
> +
> +/* Free the nodes list. */
> +static void
> +free_nodes(struct guestfs_tsk_node_list *nodes)
Having the right definition for the tsk_node struct makes the generator
add compare/free functions for each struct and list of structs, so this
function would be automatically generated already as
guestfs_free_tsk_node_list.
> +{
> + uint32_t index = 0;
> +
> + for (index = 0; index < nodes->len; index++)
> + if (nodes->val[index].tsk_name != NULL)
> + free(nodes->val[index].tsk_name);
Note that free(NULL) works (it is defined by POSIX), so you don't need
the null checks.
Thanks,
--
Pino Toscano
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