[Libguestfs] [PATCH 1/2] filesystem_walk: more information into tsk_dirent

Pino Toscano ptoscano at redhat.com
Mon Jul 4 13:25:56 UTC 2016


On Monday 04 July 2016 00:00:59 Matteo Cafasso wrote:
> Access, modification, last status change and creation time in
> Unix format as for statns.
> 
> Number of links pointing to a given entry.
> 
> If the entry is a symbolic link, report its target path.
> 
> A new flag (DIRENT_COMPRESSED 0x04) indicating whether the file is
> compressed using native filesystem compression support.
> 
> Signed-off-by: Matteo Cafasso <noxdafox at gmail.com>
> ---
>  daemon/tsk.c         | 39 +++++++++++++++++++++++++++++++--------
>  generator/actions.ml | 34 ++++++++++++++++++++++++++++++++++
>  generator/structs.ml | 20 ++++++++++----------
>  3 files changed, 75 insertions(+), 18 deletions(-)
> 
> diff --git a/daemon/tsk.c b/daemon/tsk.c
> index 446213e..8657bf3 100644
> --- a/daemon/tsk.c
> +++ b/daemon/tsk.c
> @@ -38,7 +38,8 @@
>  enum tsk_dirent_flags {
>    DIRENT_UNALLOC = 0x00,
>    DIRENT_ALLOC = 0x01,
> -  DIRENT_REALLOC = 0x02
> +  DIRENT_REALLOC = 0x02,
> +  DIRENT_COMPRESSED = 0x04
>  };
> 
>  static int open_filesystem (const char *, TSK_IMG_INFO **, TSK_FS_INFO **);
> @@ -108,6 +109,7 @@ fswalk_callback (TSK_FS_FILE *fsfile, const char *path, void *data)
>  {
>    int ret = 0;
>    CLEANUP_FREE char *fname = NULL;
> +  CLEANUP_FREE char *flink = NULL;
>    struct guestfs_int_tsk_dirent dirent;
> 
>    /* Ignore ./ and ../ */
> @@ -122,20 +124,38 @@ fswalk_callback (TSK_FS_FILE *fsfile, const char *path, void *data)
>      return TSK_WALK_ERROR;
>    }
> 
> +  /* Set dirent fields */
> +  memset (&dirent, 0, sizeof dirent);
> +
>    dirent.tsk_inode = fsfile->name->meta_addr;
>    dirent.tsk_type = file_type (fsfile);
>    dirent.tsk_size = (fsfile->meta != NULL) ? fsfile->meta->size : -1;
>    dirent.tsk_name = fname;
>    dirent.tsk_flags = file_flags (fsfile);
> -  dirent.tsk_spare1 = dirent.tsk_spare2 = dirent.tsk_spare3 =
> -    dirent.tsk_spare4 = dirent.tsk_spare5 = dirent.tsk_spare6 =
> -    dirent.tsk_spare7 = dirent.tsk_spare8 = dirent.tsk_spare9 =
> -    dirent.tsk_spare10 = dirent.tsk_spare11 = 0;
> +
> +  if (fsfile->meta != NULL) {
> +    dirent.tsk_nlink = fsfile->meta->nlink;
> +    dirent.tsk_atime_sec = fsfile->meta->atime;
> +    dirent.tsk_atime_nsec = fsfile->meta->atime_nano;
> +    dirent.tsk_mtime_sec = fsfile->meta->mtime;
> +    dirent.tsk_mtime_nsec = fsfile->meta->mtime_nano;
> +    dirent.tsk_ctime_sec = fsfile->meta->ctime;
> +    dirent.tsk_ctime_nsec = fsfile->meta->ctime_nano;
> +    dirent.tsk_crtime_sec = fsfile->meta->crtime;
> +    dirent.tsk_crtime_nsec = fsfile->meta->crtime_nano;
> +
> +    ret = asprintf (&flink, "%s", fsfile->meta->link);
> +    if (ret < 0) {
> +      perror ("asprintf");
> +      return TSK_WALK_ERROR;
> +    }

The asprintf is simply duplicating the string, so strdup can be a
better (and faster) alternative.
OTOH, why do you need to duplicate fsfile->meta->link at all, given
that the copy will be free'd at the end of the function?

> +
> +    dirent.tsk_link = flink;
> +  }

Also note that NULL values for FString in structs cannot be returned
in daemon calls, you need to have empty strings for the unset values.

> 
>    ret = send_dirent_info (&dirent);
> -  ret = (ret == 0) ? TSK_WALK_CONT : TSK_WALK_ERROR;
> 
> -  return ret;
> +  return (ret == 0) ? TSK_WALK_CONT : TSK_WALK_ERROR;

Unrelated change.

>  }
> 
>  /* Inspect fsfile to identify its type. */
> @@ -175,7 +195,7 @@ file_type (TSK_FS_FILE *fsfile)
>    return 'u';
>  }
> 
> -/* Inspect fsfile to retrieve the file allocation state. */
> +/* Inspect fsfile to retrieve file allocation and compression status. */
>  static int
>  file_flags (TSK_FS_FILE *fsfile)
>  {
> @@ -188,6 +208,9 @@ file_flags (TSK_FS_FILE *fsfile)
>    else
>      flags |= DIRENT_ALLOC;
> 
> +  if (fsfile->meta && fsfile->meta->flags & TSK_FS_META_FLAG_COMP)
> +    flags |= DIRENT_COMPRESSED;
> +
>    return flags;
>  }
> 
> diff --git a/generator/actions.ml b/generator/actions.ml
> index e0931b8..1591863 100644
> --- a/generator/actions.ml
> +++ b/generator/actions.ml
> @@ -3615,8 +3615,42 @@ This generally implies the metadata has been reallocated to a new file.
>  Therefore, information such as file type and file size
>  might not correspond with the ones of the original deleted entry.
> 
> +=item 0x0004
> +
> +The bit is set to C<1> when the file is compressed using filesystem
> +native compression support (NTFS). The API is not able to detect
> +application level compression.
> +
>  =back
> 
> +=item 'tsk_atime_sec'
> +
> +=item 'tsk_atime_nsec'
> +
> +=item 'tsk_mtime_sec'
> +
> +=item 'tsk_mtime_nsec'
> +
> +=item 'tsk_ctime_sec'
> +
> +=item 'tsk_ctime_nsec'
> +
> +=item 'tsk_crtime_sec'
> +
> +=item 'tsk_crtime_nsec'
> +
> +Respectively, access, modification, last status change and creation
> +time in Unix format in seconds and nanoseconds.
> +
> +=item 'tsk_nlink'
> +
> +Number of file names pointing to this entry.
> +
> +=item 'tsk_link'
> +
> +If the entry is a symbolic link, this field will contain the path
> +to the target file.
> +
>  =back
> 
>  The C<tsk_type> field will contain one of the following characters:
> diff --git a/generator/structs.ml b/generator/structs.ml
> index eb8931f..029bc3a 100644
> --- a/generator/structs.ml
> +++ b/generator/structs.ml
> @@ -454,17 +454,17 @@ let structs = [
>      "tsk_size", FInt64;
>      "tsk_name", FString;
>      "tsk_flags", FUInt32;
> +    "tsk_atime_sec", FInt64;
> +    "tsk_atime_nsec", FInt64;
> +    "tsk_mtime_sec", FInt64;
> +    "tsk_mtime_nsec", FInt64;
> +    "tsk_ctime_sec", FInt64;
> +    "tsk_ctime_nsec", FInt64;
> +    "tsk_crtime_sec", FInt64;
> +    "tsk_crtime_nsec", FInt64;
> +    "tsk_nlink", FInt64;
> +    "tsk_link", FString;
>      "tsk_spare1", FInt64;
> -    "tsk_spare2", FInt64;
> -    "tsk_spare3", FInt64;
> -    "tsk_spare4", FInt64;
> -    "tsk_spare5", FInt64;
> -    "tsk_spare6", FInt64;
> -    "tsk_spare7", FInt64;
> -    "tsk_spare8", FInt64;
> -    "tsk_spare9", FInt64;
> -    "tsk_spare10", FInt64;
> -    "tsk_spare11", FInt64;
>      ];
>      s_camel_name = "TSKDirent" };
> 
> --
> 2.8.1
> 
> _______________________________________________
> Libguestfs mailing list
> Libguestfs at redhat.com
> https://www.redhat.com/mailman/listinfo/libguestfs

-- 
Pino Toscano
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