Re: [Xen-devel] [PATCH] tools/xenstore: Document failure for xs_{read, directory, read_watch}

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Anthony PERARD [mailto:anthony.perard@xxxxxxxxxx]
> Sent: 05 December 2018 16:26
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Paul Durrant <Paul.Durrant@xxxxxxxxxx>; Anthony Perard
> <anthony.perard@xxxxxxxxxx>; Ian Jackson <Ian.Jackson@xxxxxxxxxx>; Wei Liu
> <wei.liu2@xxxxxxxxxx>
> Subject: [PATCH] tools/xenstore: Document failure for
> xs_{read,directory,read_watch}
> 
> Those functions can return NULL on failure, document it in the public
> header.
> 
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>

Reviewed-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

> ---
>  tools/xenstore/include/xenstore.h | 7 +++++--
>  tools/xenstore/xs.c               | 1 +
>  2 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/xenstore/include/xenstore.h
> b/tools/xenstore/include/xenstore.h
> index 889dc23863..42b2866462 100644
> --- a/tools/xenstore/include/xenstore.h
> +++ b/tools/xenstore/include/xenstore.h
> @@ -103,6 +103,7 @@ void xs_daemon_destroy_postfork(struct xs_handle *);
>  /* Get contents of a directory.
>   * Returns a malloced array: call free() on it after use.
>   * Num indicates size.
> + * Returns NULL on failure.
>   */
>  char **xs_directory(struct xs_handle *h, xs_transaction_t t,
>                   const char *path, unsigned int *num);
> @@ -110,6 +111,7 @@ char **xs_directory(struct xs_handle *h,
> xs_transaction_t t,
>  /* Get the value of a single file, nul terminated.
>   * Returns a malloced value: call free() on it after use.
>   * len indicates length in bytes, not including terminator.
> + * Returns NULL on failure.
>   */
>  void *xs_read(struct xs_handle *h, xs_transaction_t t,
>             const char *path, unsigned int *len);
> @@ -196,8 +198,9 @@ int xs_fileno(struct xs_handle *h);
>  char **xs_check_watch(struct xs_handle *h);
> 
>  /* Find out what node change was on (will block if nothing pending).
> - * Returns array containing the path and token. Use XS_WATCH_* to access
> these
> - * elements. Call free() after use.
> + * Returns array containing the path and token, or NULL.
> + * Use XS_WATCH_* to access these elements.
> + * Call free() after use.
>   */
>  char **xs_read_watch(struct xs_handle *h, unsigned int *num);
> 
> diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
> index 77700bff2b..87e43bfe87 100644
> --- a/tools/xenstore/xs.c
> +++ b/tools/xenstore/xs.c
> @@ -680,6 +680,7 @@ char **xs_directory(struct xs_handle *h,
> xs_transaction_t t,
>  /* Get the value of a single file, nul terminated.
>   * Returns a malloced value: call free() on it after use.
>   * len indicates length in bytes, not including the nul.
> + * Returns NULL on failure.
>   */
>  void *xs_read(struct xs_handle *h, xs_transaction_t t,
>             const char *path, unsigned int *len)
> --
> Anthony PERARD


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