Re: [Qemu-devel] [PATCH V3] net/colo-compare.c: Fix memory leak and code style issue.

[Philippe Mathieu-Daudé]

On 7/18/19 11:22 AM, Zhang Chen wrote:
> From: Zhang Chen <address@hidden>
> 
> This patch to fix the origin "char *data" menory leak, code style issue

"memory"

> and add necessary check here.
> Reported-by: Coverity (CID 1402785)
> 
> Signed-off-by: Zhang Chen <address@hidden>
> ---
>  net/colo-compare.c | 28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/net/colo-compare.c b/net/colo-compare.c
> index 909dd6c6eb..fcccb4c6f6 100644
> --- a/net/colo-compare.c
> +++ b/net/colo-compare.c
> @@ -127,6 +127,17 @@ static int compare_chr_send(CompareState *s,
>                              uint32_t vnet_hdr_len,
>                              bool notify_remote_frame);
>  
> +static bool packet_matches_str(const char *str,
> +                               uint8_t *buf,

You can use 'uint8_t *buf'.

> +                               uint32_t packet_len)
> +{
> +    if (packet_len != strlen(str)) {
> +        return false;
> +    }
> +
> +    return !memcmp(str, buf, strlen(str));

If you don't want to use a local variable to hold strlen(str), you can
reuse packet_len since it is the same value:

       return !memcmp(str, buf, packet_len);

However it makes the review harder, so I'd prefer using a str_len local var.

> +}
> +
>  static void notify_remote_frame(CompareState *s)
>  {
>      char msg[] = "DO_CHECKPOINT";
> @@ -1008,21 +1019,24 @@ static void 
> compare_notify_rs_finalize(SocketReadState *notify_rs)
>  {
>      CompareState *s = container_of(notify_rs, CompareState, notify_rs);
>  
> -    /* Get Xen colo-frame's notify and handle the message */
> -    char *data = g_memdup(notify_rs->buf, notify_rs->packet_len);
> -    char msg[] = "COLO_COMPARE_GET_XEN_INIT";
> +    const char msg[] = "COLO_COMPARE_GET_XEN_INIT";
>      int ret;
>  
> -    if (!strcmp(data, "COLO_USERSPACE_PROXY_INIT")) {
> +    if (packet_matches_str("COLO_USERSPACE_PROXY_INIT",
> +                           notify_rs->buf,
> +                           notify_rs->packet_len)) {
>          ret = compare_chr_send(s, (uint8_t *)msg, strlen(msg), 0, true);
>          if (ret < 0) {
>              error_report("Notify Xen COLO-frame INIT failed");
>          }
> -    }
> -
> -    if (!strcmp(data, "COLO_CHECKPOINT")) {
> +    } else if (packet_matches_str("COLO_CHECKPOINT",
> +                                  notify_rs->buf,
> +                                  notify_rs->packet_len)) {
>          /* colo-compare do checkpoint, flush pri packet and remove sec 
> packet */
>          g_queue_foreach(&s->conn_list, colo_flush_packets, s);
> +    } else {
> +        error_report("COLO compare got unsupported instruction '%s'",
> +                     (char *)notify_rs->buf);
>      }
>  }
>  
>