Re: [Xen-devel] [PATCH 14/14] livepatch: Add python bindings for livepatch operations

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

On Wed, Aug 21, 2019 at 08:19:31AM +0000, Pawel Wieczorkiewicz wrote:
> Extend the XC python bindings library to support also all common
> livepatch operations and actions.
> 
> Add the python bindings for the following operations:
> - status (pyxc_livepatch_status):
>   Requires a payload name as an input.
>   Returns a status dict containing a state string and a return code
>   integer.
> - action (pyxc_livepatch_action):
>   Requires a payload name and an action id as an input. Timeout and
>   flags are optional parameters.
>   Returns a return code integer.
> - upload (pyxc_livepatch_upload):
>   Requires a payload name and a module's filename as an input.
>   Returns a return code integer.
> - list (pyxc_livepatch_list):
>   Takes no parameters.
>   Returns a list of dicts containing each payload's:
>   * name as a string
>   * state as a string
>   * return code as an integer
>   * list of metadata key=value strings
> 
> Each functions throws an exception error based on the errno value
> received from its corresponding libxc function call.
> 
> Signed-off-by: Pawel Wieczorkiewicz <wipawel@xxxxxxxxx>
> Reviewed-by: Martin Mazein <amazein@xxxxxxxxx>
> Reviewed-by: Andra-Irina Paraschiv <andraprs@xxxxxxxxxx>
> Reviewed-by: Leonard Foerster <foersleo@xxxxxxxxx>
> Reviewed-by: Norbert Manthey <nmanthey@xxxxxxxxx>
> ---
>  tools/python/xen/lowlevel/xc/xc.c | 273 
> ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 273 insertions(+)
> 
> diff --git a/tools/python/xen/lowlevel/xc/xc.c 
> b/tools/python/xen/lowlevel/xc/xc.c
> index 7f0358ba9c..368739b996 100644
> --- a/tools/python/xen/lowlevel/xc/xc.c
> +++ b/tools/python/xen/lowlevel/xc/xc.c

(...)
> +static PyObject *pyxc_livepatch_list(XcObject *self)
> +{
> +    PyObject *list;
> +    unsigned int nr, done, left, i;
> +    xen_livepatch_status_t *info = NULL;
> +    char *name = NULL;
> +    char *metadata = NULL;
> +    uint32_t *len = NULL;
> +    uint32_t *metadata_len = NULL;
> +    uint64_t name_total_size, metadata_total_size;
> +    off_t name_off, metadata_off;
> +    int rc;
> +
> +    rc = xc_livepatch_list_get_sizes(self->xc_handle, &nr,
> +                                     &name_total_size, &metadata_total_size);
> +    if ( rc )
> +        goto error;
> +
> +    if ( nr == 0 )
> +        return PyList_New(0);
> +
> +    rc = ENOMEM;
> +    info = malloc(nr * sizeof(*info));
> +    if ( !info )
> +        goto error;
> +
> +    name = malloc(name_total_size * sizeof(*name));
> +    if ( !name )
> +        goto error;
> +
> +    len = malloc(nr * sizeof(*len));
> +    if ( !len )
> +        goto error;
> +
> +    metadata = malloc(metadata_total_size * sizeof(*metadata));
> +    if ( !metadata )
> +        goto error;
> +
> +    metadata_len = malloc(nr * sizeof(*metadata_len));
> +    if ( !metadata_len )
> +        goto error;
> +
> +    rc = xc_livepatch_list(self->xc_handle, nr, 0, info,
> +                           name, len, name_total_size,
> +                           metadata, metadata_len, metadata_total_size,
> +                           &done, &left);
> +    if ( rc )
> +        goto error;
> +
> +    list = PyList_New(0);

Previous remark stays:
Better use PyList_New(done) and later PyList_SetItem() instead of 
PyList_Append().

> +    name_off = metadata_off = 0;
> +    for ( i = 0; i < done; i++ )
> +    {
> +        PyObject *info_dict, *metadata_list;
> +        char *name_str, *metadata_str;
> +
> +        name_str = name + name_off;
> +        metadata_str = metadata + metadata_off;
> +
> +        metadata_list = PyList_New(0);
> +        for ( char *s = metadata_str; s < metadata_str + metadata_len[i]; s 
> += strlen(s) + 1 )
> +        {
> +            PyObject *field = Py_BuildValue("s", s);
> +            if ( field == NULL )
> +            {
> +                Py_DECREF(list);
> +                Py_DECREF(metadata_list);
> +                rc = EFAULT;
> +                goto error;
> +            }
> +
> +            PyList_Append(metadata_list, field);
> +            Py_DECREF(field);
> +        }
> +
> +        info_dict = Py_BuildValue(
> +            "{s:s,s:i,s:i,s:N}",
> +            "name",     name_str,
> +            "state",    info[i].state,
> +            "rc",       info[i].rc,
> +            "metadata", metadata_list);
> +
> +        if ( info_dict == NULL )
> +        {
> +            Py_DECREF(list);
> +            Py_DECREF(metadata_list);
> +            rc = EFAULT;
> +            goto error;
> +        }
> +        PyList_Append(list, info_dict);
> +        Py_DECREF(info_dict);
> +
> +        name_off += len[i];
> +        metadata_off += metadata_len[i];
> +    }
> +
> +error:
> +    free(info);
> +    free(name);
> +    free(len);
> +    free(metadata);
> +    free(metadata_len);
> +    return rc ? pyxc_error_to_exception(self->xc_handle) : list;
> +}
> +
>  static PyMethodDef pyxc_methods[] = {
>      { "domain_create", 
>        (PyCFunction)pyxc_domain_create, 

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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