Re: [Libguestfs] [PATCH] inspect: get windows drive letters for GPT disks.

On Fri, Feb 05, 2016 at 12:15:32PM -0500, Dawid Zamirski wrote: > This patch updates the guestfs_inspect_get_drive_mappings API call > to > also return drive letters for GPT paritions. Previously this worked > only for MBR partitions. This is achieved by matching the GPT > partition > GUID with the info stored in the blob from > HKLM\SYSTEM\MountedDevices\DosDevices keys. For GPT partions this > blob > contains a "DMIO:ID:" prefix followed by a 16 byte binary GUID. > --- >  src/inspect-fs-windows.c | 98 > +++++++++++++++++++++++++++++++++++++++++++++++- >  1 file changed, 96 insertions(+), 2 deletions(-) Attached is a patch with some stylistic updates.  Please combine it with your patch.  More comments below. > diff --git a/src/inspect-fs-windows.c b/src/inspect-fs-windows.c > index ccf5cba..6571d37 100644 > --- a/src/inspect-fs-windows.c > +++ b/src/inspect-fs-windows.c > @@ -25,6 +25,7 @@ >  #include <string.h> >  #include <errno.h> >  #include <iconv.h> > +#include <inttypes.h> >   >  #ifdef HAVE_ENDIAN_H >  #include <endian.h> > @@ -57,6 +58,8 @@ static int check_windows_arch (guestfs_h *g, > struct inspect_fs *fs); >  static int check_windows_software_registry (guestfs_h *g, struct > inspect_fs *fs); >  static int check_windows_system_registry (guestfs_h *g, struct > inspect_fs *fs); >  static char *map_registry_disk_blob (guestfs_h *g, const void > *blob); > +static char *map_registry_disk_blob_gpt(guestfs_h *g, const void > *blob); > +static char *extract_guid_from_registry_blob(guestfs_h *g, const > void *blob); >   >  /* XXX Handling of boot.ini in the Perl version was pretty > broken.  It >   * essentially didn't do anything for modern Windows guests. > @@ -386,6 +389,7 @@ check_windows_system_registry (guestfs_h *g, > struct inspect_fs *fs) >    int r; >    size_t len = strlen (fs->windows_systemroot) + 64; >    char system[len]; > +  char gpt_prefix[] = "DMIO:ID:"; >    snprintf (system, len, "%s/system32/config/system", >              fs->windows_systemroot); >   > @@ -493,9 +497,14 @@ check_windows_system_registry (guestfs_h *g, > struct inspect_fs *fs) >   >        type = guestfs_hivex_value_type (g, v); >        blob = guestfs_hivex_value_value (g, v, &len); > -      if (blob != NULL && type == 3 && len == 12) { > +      bool is_gpt = memcmp(blob, gpt_prefix, 8) == 0; > +      if (blob != NULL && type == 3 && (len == 12 || is_gpt)) { >          /* Try to map the blob to a known disk and partition. */ > -        device = map_registry_disk_blob (g, blob); > +        if (is_gpt) > +          device = map_registry_disk_blob_gpt (g, blob); > +        else > +          device = map_registry_disk_blob (g, blob); > + >          if (device != NULL) { >            fs->drive_mappings[count++] = safe_strndup (g, &key[12], > 1); >            fs->drive_mappings[count++] = device; > @@ -605,6 +614,91 @@ map_registry_disk_blob (guestfs_h *g, const > void *blob) >    return safe_asprintf (g, "%s%d", devices[i], partitions- > >val[j].part_num); >  } >   > +/* Matches Windows registry HKLM\SYSYTEM\MountedDevices\DosDevices > blob to > + * to libguestfs GPT partition device. For GPT disks, the blob is > made of > + * "DMIO:ID:" prefix followed by the GPT parition GUID. > + */ > +static char * > +map_registry_disk_blob_gpt (guestfs_h *g, const void *blob) > +{ > +  CLEANUP_FREE_STRING_LIST char **fses = NULL; > +  size_t i; > + > +  fses = guestfs_list_filesystems (g); > +  if (fses == NULL) > +    return NULL; Did you really mean to call guestfs_list_filesystems here?  If you're trying to get the list of partitions, then guestfs_list_partitions is what you should be calling.

> +  for (i = 0; fses[i] != NULL; i += 2) { > +    CLEANUP_FREE char *fs_guid = NULL; > +    CLEANUP_FREE char *blob_guid = NULL; > +    CLEANUP_FREE char *fs_dev  = NULL; > + > +    fs_dev = guestfs_canonical_device_name (g, fses[i]); > + > +    if (fs_dev == NULL) > +        continue; > + > +    int partnum = guestfs_part_to_partnum (g, fs_dev); Need to check that partnum != -1 and do something. > +    CLEANUP_FREE char *device = guestfs_part_to_dev (g, fs_dev); > +    CLEANUP_FREE char *type = guestfs_part_get_parttype (g, > device); > + > +    if (STRCASENEQ(type, "gpt")) > +        continue; > + > +    /* get the GPT parition GUID from the partition block device > */ > +    fs_guid = guestfs_part_get_gpt_guid (g, device, partnum); > +     > +    if (fs_guid == NULL) > +      continue; > + > +    /* extract the GUID from the Windows registry blob */ > +    blob_guid = extract_guid_from_registry_blob (g, blob); > + > +    /* if both GUIDs match, we have found mapping for out device > */ > +    if (STRCASEEQ (fs_guid, blob_guid)) > +        return safe_strdup (g, fs_dev); > +  } > + > +  return NULL; > +} > + > +/* Extracts the binary GUID stored in blob from Windows registry  > + * HKLM\SYSTYEM\MountedDevices\DosDevices value and converts it to > a GUID string > + * so that it can be matched against libguestfs partition device > GPT GUID. > + */ > +static char * > +extract_guid_from_registry_blob (guestfs_h *g, const void *blob) > +{ > +  char guid_bytes[16]; > +  size_t len = 37; > +  uint32_t data1; > +  uint16_t data2, data3; > +  uint64_t data4; > + > +  char *guid = (char *) safe_calloc(g, len, sizeof (char * )); > + > +  /* get the GUID bytes from blob (skip 8 byte "DMIO:ID:" prefix) > */ > +  memcpy (&guid_bytes, (char *) blob + 8, sizeof (guid_bytes)); > + > +  /* copy relevant sections from blob to respective ints */ > +  memcpy (&data1, guid_bytes, sizeof (data1)); > +  memcpy (&data2, guid_bytes + 4, sizeof (data2)); > +  memcpy (&data3, guid_bytes + 6, sizeof (data3)); > +  memcpy (&data4, guid_bytes + 8, sizeof (data4)); > + > +  /* ensure proper endianness */ > +  data1 = htole32 (data1); Did you mean to use htole32?  Surely it should be le32toh?

> +  data2 = htole16 (data2); > +  data3  = htole16 (data3); > +  data4 = htobe64 (data4); And is this really big endian?

Rich.