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

[Jerone Young <jyoung5@xxxxxxxxxx>]

On Wed, 2005-11-23 at 17:40 -0600, Anthony Liguori wrote:
> Unfortunately, this patch introduces another potential segfault from an 
> unterminated string.  See below for how to fix.

Actually I believe this is not true as I am assigning a character and
not a character string. You do not need to null terminate a character.
Doesn't really matter both accomplish the same thing. Using the function
is better anyway.

> 
> 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;
> > }   
> >  
> >
> >------------------------------------------------------------------------
> >
> >_______________________________________________
> >Xen-devel mailing list
> >Xen-devel@xxxxxxxxxxxxxxxxxxx
> >http://lists.xensource.com/xen-devel
> >  
> >
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
> 


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel