[Libguestfs] [PATCH v2 3/5] daemon: Added internal_filesystem_walk command

[Pino Toscano]

On Monday 04 April 2016 23:07:05 noxdafox wrote:
> On 04/04/16 15:15, Pino Toscano wrote:
> > On Monday 04 April 2016 14:58:35 NoxDaFox wrote:
> >>>> +
> >>>> +static int open_filesystem (const char *device,
> >>>> +                            TSK_IMG_INFO **img, TSK_FS_INFO **fs);
> >>>> +static TSK_WALK_RET_ENUM fswalk_callback (TSK_FS_FILE *fsfile,
> >>>> +                                          const char *path, void *data);
> >>> Single line for forward declarations.
> >>>
> >> Even if they are longer than 80 chars?
> > Yep.
> >
> >>>> +static char file_type (TSK_FS_FILE *fsfile);
> >>>> +static int send_dirent_info (guestfs_int_tsk_dirent *dirent);
> >>>> +static void reply_with_tsk_error (const char *funcname);
> >>>> +
> >>>> +int
> >>>> +do_internal_filesystem_walk (const mountable_t *mountable)
> >>>> +{
> >>>> +  int ret = -1;
> >>>> +  TSK_FS_INFO *fs = NULL;
> >>>> +  TSK_IMG_INFO *img = NULL;  /* Used internally by tsk_fs_dir_walk */
> >>>> +  int flags = TSK_FS_DIR_WALK_FLAG_ALLOC | TSK_FS_DIR_WALK_FLAG_UNALLOC
> >>> |
> >>>> +    TSK_FS_DIR_WALK_FLAG_RECURSE | TSK_FS_DIR_WALK_FLAG_NOORPHAN;
> >>>> +
> >>>> +  ret = open_filesystem (mountable->device, &img, &fs);
> >>>> +  if (ret < 0)
> >>>> +    return ret;
> >>>> +
> >>>> +  reply (NULL, NULL);  /* Reply message. */
> >>>> +
> >>>> +  ret = tsk_fs_dir_walk (fs, fs->root_inum, flags, fswalk_callback,
> >>> NULL);
> >>>> +  if (ret == 0)
> >>>> +    ret = send_file_end (0);  /* File transfer end. */
> >>>> +  else
> >>>> +    send_file_end (1);  /* Cancel file transfer. */
> >>>> +
> >>>> +  fs->close (fs);
> >>>> +  img->close (img);
> >>>> +
> >>>> +  return ret;
> >>>> +}
> >>>> +
> >>>> +/* Inspect the device and initialises the img and fs structures.
> >>>> + * Return 0 on success, -1 on error.
> >>>> + */
> >>>> +static int
> >>>> +open_filesystem (const char *device, TSK_IMG_INFO **img, TSK_FS_INFO
> >>> **fs)
> >>>> +{
> >>>> +  const char *images[] = { device };
> >>>> +
> >>>> +  *img = tsk_img_open (1, images, TSK_IMG_TYPE_DETECT , 0);
> >>>> +  if (*img == NULL) {
> >>>> +    reply_with_tsk_error ("tsk_image_open");
> >>>> +    return -1;
> >>>> +  }
> >>>> +
> >>>> +  *fs = tsk_fs_open_img (*img, 0, TSK_FS_TYPE_DETECT);
> >>>> +  if (*fs == NULL) {
> >>>> +    reply_with_tsk_error ("tsk_fs_open_img");
> >>>> +    (*img)->close (*img);
> >>>> +    return -1;
> >>>> +  }
> >>>> +
> >>>> +  return 0;
> >>>> +}
> >>>> +
> >>>> +/* Filesystem walk callback, it gets called on every FS node.
> >>>> + * Parse the node, encode it into an XDR structure and send it to the
> >>> appliance.
> >>>> + * Return TSK_WALK_CONT on success, TSK_WALK_ERROR on error.
> >>>> + */
> >>>> +static TSK_WALK_RET_ENUM
> >>>> +fswalk_callback (TSK_FS_FILE *fsfile, const char *path, void *data)
> >>>> +{
> >>>> +  int ret = 0;
> >>>> +  CLEANUP_FREE char *fname = NULL;
> >>>> +  struct guestfs_int_tsk_dirent dirent;
> >>>> +
> >>>> +  /* Ignore ./ and ../ */
> >>>> +  ret = TSK_FS_ISDOT (fsfile->name->name);
> >>>> +  if (ret != 0)
> >>>> +    return TSK_WALK_CONT;
> >>>> +
> >>>> +  /* Build the full relative path of the entry */
> >>>> +  ret = asprintf_nowarn (&fname, "%Q%Q", path, fsfile->name->name);
> >>> Why the quoting?  We don't quote results in similar APIs (e.g. readdir).
> >>>
> >> I didn't understand this one. I checked daemon/readdir.c and I found no
> >> asprintf examples there.
> > $ ./run guestfish -N fs -m /dev/sda1 touch "/file with spaces" : readdir /
> > [0] = {
> >    ino: 12
> >    ftyp: r
> >    name: file with spaces
> > }
> > [1] = {
> >    ino: 2
> >    ftyp: d
> >    name: .
> > }
> > [2] = {
> >    ino: 11
> >    ftyp: d
> >    name: lost+found
> > }
> > [3] = {
> >    ino: 2
> >    ftyp: d
> >    name: ..
> > }
> >
> > You can see the file names are not quoted.
> 
> As long as I'm not missing something, the double quote there is not 
> adding quotes to the names but passing the string formatting parameter 
> to 'asprintf'.
> int asprintf(char **strp, const char *fmt, ...);
> 
> If I remove it, I get this error.
> 
> tsk.c: In function 'fswalk_callback':
> tsk.c:112:34: error: expected expression before '%' token
>     ret = asprintf_nowarn (&fname, %Q%Q, path, fsfile->name->name);
> 
> If I keep it, I get this output.
> 
> ./run guestfish --ro -a ubuntu.qcow2 run : filesystem_walk /dev/sda1 | less
> [0] = {
>    tsk_inode: 11
>    tsk_type: d
>    tsk_size: 16384
>    tsk_name: lost\+found
>    tsk_allocated: 1
> }
> [1] = {
>    tsk_inode: 12
>    tsk_type: l
>    tsk_size: 33
>    tsk_name: initrd.img
>    tsk_allocated: 1
> }
> 
> As you can see names are not quoted.

Sorry, I said "quoted" because of %Q -- they are escaped.  Just join
path and filename without escaping them.

-- 
Pino Toscano
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