[Libguestfs] [PATCH] lib: update inspect_list_applications to return app_arch (RHBZ#859949)
Richard W.M. Jones
rjones at redhat.com
Mon Oct 15 21:00:15 UTC 2012
On Mon, Oct 15, 2012 at 04:30:24PM -0400, John Eckersberg wrote:
> (Work in progress)
>
> For now this only works for RPM, the others just return an empty string.
> ---
> generator/structs.ml | 1 +
> src/inspect-apps.c | 88 +++++++++++++++++++++++++++++-----------------------
> 2 files changed, 51 insertions(+), 38 deletions(-)
>
> diff --git a/generator/structs.ml b/generator/structs.ml
> index d62fcc5..8ac9fc5 100644
> --- a/generator/structs.ml
> +++ b/generator/structs.ml
> @@ -183,6 +183,7 @@ let structs = [
> "app_epoch", FInt32;
> "app_version", FString;
> "app_release", FString;
> + "app_arch", FString;
> "app_install_path", FString;
> "app_trans_path", FString;
> "app_publisher", FString;
Unfortunately (and this a rather serious shortcoming of the generator)
you cannot add fields to an existing struct and maintain backwards
binary compatibility. Let's not worry about this bit right now
though, I need to think about what to do a bit more.
> diff --git a/src/inspect-apps.c b/src/inspect-apps.c
> index f65c70a..3dbfb5b 100644
> --- a/src/inspect-apps.c
> +++ b/src/inspect-apps.c
> @@ -31,6 +31,7 @@
> #ifdef HAVE_ENDIAN_H
> #include <endian.h>
> #endif
> +#include <arpa/inet.h>
Don't need this -- see below.
> #include <pcre.h>
>
> @@ -46,7 +47,7 @@ static struct guestfs_application_list *list_applications_rpm (guestfs_h *g, str
> #endif
> static struct guestfs_application_list *list_applications_deb (guestfs_h *g, struct inspect_fs *fs);
> static struct guestfs_application_list *list_applications_windows (guestfs_h *g, struct inspect_fs *fs);
> -static void add_application (guestfs_h *g, struct guestfs_application_list *, const char *name, const char *display_name, int32_t epoch, const char *version, const char *release, const char *install_path, const char *publisher, const char *url, const char *description);
> +static void add_application (guestfs_h *g, struct guestfs_application_list *, const char *name, const char *display_name, int32_t epoch, const char *version, const char *release, const char *arch, const char *install_path, const char *publisher, const char *url, const char *description);
> static void sort_applications (struct guestfs_application_list *);
>
> /* Unlike the simple inspect-get-* calls, this one assumes that the
> @@ -181,6 +182,37 @@ read_rpm_name (guestfs_h *g,
> return 0;
> }
>
> +/* tag constants, see rpmtag.h in RPM for complete list */
> +#define RPMTAG_VERSION 1001
> +#define RPMTAG_RELEASE 1002
> +#define RPMTAG_ARCH 1022
> +
> +static char *
> +get_rpm_header_tag (guestfs_h *g, const void *header_start, size_t header_len, uint32_t tag)
> +{
> + uint32_t num_fields, offset;
> + const void *cursor = header_start + 8, *store;
> +
> + /* This function parses the RPM header structure to pull out various
> + * tag strings (version, release, arch, etc.). For more detail on the
> + * header format, see:
> + * http://www.rpm.org/max-rpm/s1-rpm-file-format-rpm-file-format.html#S2-RPM-FILE-FORMAT-HEADER
> + */
> +
> + num_fields = ntohl (*(uint32_t *) header_start);
It's probably better to use the functions from <endian.h> like
'be32toh', 'le32toh' etc. We already use them, eg. in
src/inspect-fs-windows.c.
> + store = header_start + 8 + (16 * num_fields);
> +
> + while (cursor < store ){
> + if (ntohl (*(uint32_t *) cursor) == tag){
> + offset = ntohl(*(uint32_t *) (cursor + 8));
> + return safe_strdup(g, store + offset);
> + }
> + cursor += 16;
Can a malicious RPM in the guest cause an infinite loop in the host?
> + }
> +
> + return NULL;
> +}
> +
> struct read_package_data {
> struct rpm_names_list *list;
> struct guestfs_application_list *apps;
> @@ -194,16 +226,13 @@ read_package (guestfs_h *g,
> {
> struct read_package_data *data = datav;
> struct rpm_name nkey, *entry;
> - char *p;
> - size_t len;
> - ssize_t max;
> - char *nul_name_nul, *version, *release;
> + char *version, *release, *arch;
>
> /* This function reads one (key, value) pair from the Packages
> * database. The key is the link field (see struct rpm_name). The
> - * value is a long binary string, but we can extract the version
> - * number from it as below. First we have to look up the link field
> - * in the list of links (which is sorted by link field).
> + * value is a long binary string, but we can extract the header data
> + * from it as below. First we have to look up the link field in the
> + * list of links (which is sorted by link field).
> */
>
> /* Ignore bogus entries. */
> @@ -219,41 +248,23 @@ read_package (guestfs_h *g,
>
> /* We found a matching link entry, so that gives us the application
> * name (entry->name). Now we can get other data for this
> - * application out of the binary value string. XXX This is a real
> - * hack.
> + * application out of the binary value string.
> */
>
> - /* Look for \0<name>\0 */
> - len = strlen (entry->name);
> - nul_name_nul = safe_malloc (g, len + 2);
> - nul_name_nul[0] = '\0';
> - memcpy (&nul_name_nul[1], entry->name, len);
> - nul_name_nul[len+1] = '\0';
> - p = memmem (value, valuelen, nul_name_nul, len+2);
> - free (nul_name_nul);
> - if (!p)
> - return 0;
> -
> - /* Following that are \0-delimited version and release fields. */
> - p += len + 2; /* Note we have to skip \0 + name + \0. */
> - max = valuelen - (p - (char *) value);
> - if (max < 0)
> - max = 0;
> - version = safe_strndup (g, p, max);
> -
> - len = strlen (version);
> - p += len + 1;
> - max = valuelen - (p - (char *) value);
> - if (max < 0)
> - max = 0;
> - release = safe_strndup (g, p, max);
> + version = get_rpm_header_tag(g, value, valuelen, RPMTAG_VERSION);
> + release = get_rpm_header_tag(g, value, valuelen, RPMTAG_RELEASE);
> + arch = get_rpm_header_tag(g, value, valuelen, RPMTAG_ARCH);
Good, this seems like a considerable improvement.
> /* Add the application and what we know. */
> add_application (g, data->apps, entry->name, "", 0, version, release,
> - "", "", "", "");
> + arch ? arch : "(none)", "", "", "", "");
Don't use "(none)". If you need a special value, use either "" or
"unknown" (I suspect in this case empty string), and document it in
the API (generator/actions.ml).
> free (version);
> free (release);
> + if (arch)
> + /* arch will occasionally be NULL, because some packages
> + * (e.g. "gpgkeys") do not have an arch */
> + free (arch);
>
> return 0;
> }
> @@ -378,7 +389,7 @@ list_applications_deb (guestfs_h *g, struct inspect_fs *fs)
> else if (STREQ (line, "")) {
> if (installed_flag && name && version)
> add_application (g, apps, name, "", 0, version, release ? : "",
> - "", "", "", "");
> + "", "", "", "", "");
> free (name);
> free (version);
> free (release);
> @@ -519,7 +530,7 @@ list_applications_windows_from_path (guestfs_h *g,
>
> add_application (g, apps, name, display_name, 0,
> version ? : "",
> - "",
> + "", "",
> install_path ? : "",
> publisher ? : "",
> url ? : "",
> @@ -542,7 +553,7 @@ list_applications_windows_from_path (guestfs_h *g,
> static void
> add_application (guestfs_h *g, struct guestfs_application_list *apps,
> const char *name, const char *display_name, int32_t epoch,
> - const char *version, const char *release,
> + const char *version, const char *release, const char *arch,
> const char *install_path,
> const char *publisher, const char *url,
> const char *description)
> @@ -555,6 +566,7 @@ add_application (guestfs_h *g, struct guestfs_application_list *apps,
> apps->val[apps->len-1].app_epoch = epoch;
> apps->val[apps->len-1].app_version = safe_strdup (g, version);
> apps->val[apps->len-1].app_release = safe_strdup (g, release);
> + apps->val[apps->len-1].app_arch = safe_strdup (g, arch);
> apps->val[apps->len-1].app_install_path = safe_strdup (g, install_path);
> /* XXX Translated path is not implemented yet. */
> apps->val[apps->len-1].app_trans_path = safe_strdup (g, "");
> --
> 1.7.11.4
Does it work?
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines. Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v
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