Re: [Xen-devel] [PATCH] Fix random segfaults in with xm top

[Anthony Liguori <aliguori@xxxxxxxxxx>]

Unfortunately, this patch introduces another potential segfault from an 
unterminated string.  See below for how to fix.
Jerone Young wrote:

> # HG changeset patch
> # User root@leaf1
> # Node ID 7ce2dfd820e39c7764f276a785415014a7954861
> # Parent  14d733e5e1d014e302d72fb78df1428ee08e3ce3
> * fix random segfaults in xentop by never returning null
> * remove xenstore transcations (not needed).
>
> diff -r 14d733e5e1d0 -r 7ce2dfd820e3 tools/xenstat/libxenstat/src/xenstat.c
> --- a/tools/xenstat/libxenstat/src/xenstat.c    Wed Nov 23 13:15:35 2005
> +++ b/tools/xenstat/libxenstat/src/xenstat.c    Wed Nov 23 19:17:11 2005
> @@ -702,19 +702,16 @@
> {
>         char path[80];
>         char *name;
> -       struct xs_transaction_handle *xstranshandle;
>
>         snprintf(path, sizeof(path),"/local/domain/%i/name", domain_id);
>         
> -       xstranshandle = xs_transaction_start(handle->xshandle);
> -       if (xstranshandle == NULL) {
> -               perror("Unable to get transcation handle from xenstore\n");
> -               exit(1); /* Change this */
> -       }
> -
> -       name = (char *) xs_read(handle->xshandle, xstranshandle, path, NULL);
> +       name = (char *) xs_read(handle->xshandle, NULL, path, NULL);
>         
> -       xs_transaction_end(handle->xshandle, xstranshandle, false);
> +       if (name == NULL)
> +       {
> +               name = (char *)malloc((size_t)sizeof(char));
> +               name[0] = ' ';
> +	}	 
>  
-               name = (char *)malloc((size_t)sizeof(char));
-               name[0] = ' ';
+               name = malloc(2);
+               name[0] = ' ';
+               name[1] = 0;

Or better yet:

-               name = (char *)malloc((size_t)sizeof(char));
-               name[0] = ' ';
+               name = strdup(" ");

Regards,

Anthony Liguori

>  
>
>         return name;
> }       
>  
>
> ------------------------------------------------------------------------
>
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