[Libguestfs] [PATCH] daemon: xattr: factorize do_getxattr and do_lgetxattr

[Richard W.M. Jones]

On Wed, Apr 30, 2014 at 04:00:20PM +0200, Pino Toscano wrote:
> Move all the common code to a new _getxattr function, much like done for
> other xattrs operations.
> 
> Mostly code motion, no functional changes.
> ---
>  daemon/xattr.c | 54 +++++++++++-------------------------------------------
>  1 file changed, 11 insertions(+), 43 deletions(-)
> 
> diff --git a/daemon/xattr.c b/daemon/xattr.c
> index abed5ff..d8ad59a 100644
> --- a/daemon/xattr.c
> +++ b/daemon/xattr.c
> @@ -55,6 +55,7 @@ static guestfs_int_xattr_list *getxattrs (const char *path, ssize_t (*listxattr)
>  static int _setxattr (const char *xattr, const char *val, int vallen, const char *path, int (*setxattr) (const char *path, const char *name, const void *value, size_t size, int flags));
>  static int _removexattr (const char *xattr, const char *path, int (*removexattr) (const char *path, const char *name));
>  static char *_listxattrs (const char *path, ssize_t (*listxattr) (const char *path, char *list, size_t size), ssize_t *size);
> +static char *_getxattr (const char *name, const char *path, ssize_t (*getxattr) (const char *path, const char *name, void *value, size_t size), size_t *size_r);
>  
>  guestfs_int_xattr_list *
>  do_getxattrs (const char *path)
> @@ -448,6 +449,15 @@ do_internal_lxattrlist (const char *path, char *const *names)
>  char *
>  do_getxattr (const char *path, const char *name, size_t *size_r)
>  {
> +  return _getxattr (name, path, getxattr, size_r);
> +}
> +
> +static char *
> +_getxattr (const char *name, const char *path,
> +           ssize_t (*getxattr) (const char *path, const char *name,
> +                                void *value, size_t size),
> +           size_t *size_r)
> +{
>    ssize_t r;
>    char *buf;
>    size_t len;
> @@ -496,49 +506,7 @@ do_getxattr (const char *path, const char *name, size_t *size_r)
>  char *
>  do_lgetxattr (const char *path, const char *name, size_t *size_r)
>  {
> -  ssize_t r;
> -  char *buf;
> -  size_t len;
> -
> -  CHROOT_IN;
> -  r = lgetxattr (path, name, NULL, 0);
> -  CHROOT_OUT;
> -  if (r == -1) {
> -    reply_with_perror ("lgetxattr");
> -    return NULL;
> -  }
> -
> -  len = r;
> -
> -  if (len > XATTR_SIZE_MAX) {
> -    reply_with_error ("extended attribute is too large");
> -    return NULL;
> -  }
> -
> -  buf = malloc (len);
> -  if (buf == NULL) {
> -    reply_with_perror ("malloc");
> -    return NULL;
> -  }
> -
> -  CHROOT_IN;
> -  r = lgetxattr (path, name, buf, len);
> -  CHROOT_OUT;
> -  if (r == -1) {
> -    reply_with_perror ("lgetxattr");
> -    free (buf);
> -    return NULL;
> -  }
> -
> -  if (len != (size_t) r) {
> -    reply_with_error ("lgetxattr: unexpected size (%zu/%zd)", len, r);
> -    free (buf);
> -    return NULL;
> -  }
> -
> -  /* Must set size_r last thing before returning. */
> -  *size_r = len;
> -  return buf; /* caller frees */
> +  return _getxattr (name, path, lgetxattr, size_r);
>  }

It's a minor thing, but this changes the error messages, so that they
will say things like "getxattr: <errno string>" instead of "lgetxattr: ...".

It would be good to pass in the name of the function as a string to
_getxattr so that it can print the name correctly in error messages.

ACK with that change.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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