[PATCH 02/10] ch_monitor: Update virCHMonitorGet to handle accept a response

[Michal Prívozník]

On 6/30/21 1:05 AM, William Douglas wrote:
> The virCHMonitorGet function needed to be able to return data from the
> hypervisor. This functionality is needed in order for the driver to
> support PTY enablement and getting details about the VM state.
> 
> Signed-off-by: William Douglas <william.douglas at intel.com>
> ---
>  src/ch/ch_monitor.c | 37 +++++++++++++++++++++++++++++++++++--
>  1 file changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/src/ch/ch_monitor.c b/src/ch/ch_monitor.c
> index f76bc2b423..93a5f8fdb4 100644
> --- a/src/ch/ch_monitor.c
> +++ b/src/ch/ch_monitor.c
> @@ -612,12 +612,33 @@ virCHMonitorPutNoContent(virCHMonitor *mon, const char *endpoint)
>      return ret;
>  }
>  
> +struct curl_data {
> +    char *content;
> +    size_t size;
> +};
> +
> +static size_t
> +curl_callback(void *contents, size_t size, size_t nmemb, void *userp)
> +{
> +    size_t content_size = size * nmemb;
> +    struct curl_data *data = (struct curl_data *)userp;
> +
> +    data->content = g_malloc0(content_size + 1);

We prefer g_new(char, ...), but ...

> +    memcpy(data->content, contents, content_size);
> +    data->content[content_size] = 0;
> +    data->size = content_size;
> +
> +    return content_size;

.. are we sure that the incoming data is split into small enough hunks
that this function is called just once? I mean, the other WRITEFUNCTION
callbacks we have in our code are aware of this and pick up where the
previous run dropped.

> +}
> +
>  static int
> -virCHMonitorGet(virCHMonitor *mon, const char *endpoint)
> +virCHMonitorGet(virCHMonitor *mon, const char *endpoint, virJSONValue **response)
>  {
>      g_autofree char *url = NULL;
>      int responseCode = 0;
>      int ret = -1;
> +    struct curl_slist *headers = NULL;
> +    struct curl_data data;
>  
>      url = g_strdup_printf("%s/%s", URL_ROOT, endpoint);
>  
> @@ -629,12 +650,24 @@ virCHMonitorGet(virCHMonitor *mon, const char *endpoint)
>      curl_easy_setopt(mon->handle, CURLOPT_UNIX_SOCKET_PATH, mon->socketpath);
>      curl_easy_setopt(mon->handle, CURLOPT_URL, url);
>  
> +    if (response) {
> +        headers = curl_slist_append(headers, "Accept: application/json");
> +        headers = curl_slist_append(headers, "Content-Type: application/json");
> +        curl_easy_setopt(mon->handle, CURLOPT_HTTPHEADER, headers);
> +        curl_easy_setopt(mon->handle, CURLOPT_WRITEFUNCTION, curl_callback);
> +        curl_easy_setopt(mon->handle, CURLOPT_WRITEDATA, (void *)&data);
> +    }
> +
>      responseCode = virCHMonitorCurlPerform(mon->handle);
>  
>      virObjectUnlock(mon);
>  
> -    if (responseCode == 200 || responseCode == 204)
> +    if (responseCode == 200 || responseCode == 204) {
>          ret = 0;
> +        if (response) {
> +            *response = virJSONValueFromString(data.content);

data.content is not eaten by virJSONValueFromString(). You need to free
it explicitly.

> +        }
> +    }
>  
>      return ret;
>  }
> 

Michal