issue with devstat_buildmatch(3) and certain strings

[Sergey Kandaurov]

On 1 April 2011 01:03, Alexander Best <arundel at freebsd.org> wrote:
> hi there,
>
> devstat_buildmatch(3) crashes with certain strings. you can test this by
> doing one of:
>
> iostat -t ","
> iostat -t ",,"
> iostat -t "da,"
> iostat -t ",da,"
> iostat -t ",da"
> iostat -t "da,scsi,"
> iostat -t ",da,scsi"
> iostat -t "da,,scsi"

[Someone told me, -hackers isn't appropriate for patches, Cc: -current.]

The problem is devstat(3) increments num_args regardless if strsep
returned NULL.
I think that should work (all your tests pass):

Index: lib/libdevstat/devstat.c
===================================================================
--- lib/libdevstat/devstat.c    (revision 220102)
+++ lib/libdevstat/devstat.c    (working copy)
@@ -1014,11 +1014,12 @@
         * Break the (comma delimited) input string out into separate strings.
         */
        for (tempstr = tstr, num_args  = 0;
-            (*tempstr = strsep(&match_str, ",")) != NULL && (num_args < 5);
-            num_args++)
-               if (**tempstr != '\0')
+            (*tempstr = strsep(&match_str, ",")) != NULL && (num_args < 5); )
+               if (**tempstr != '\0') {
+                       num_args++;
                        if (++tempstr >= &tstr[5])
                                break;
+               }

        /* The user gave us too many type arguments */
        if (num_args > 3) {

Please review, and I will commit the patch.

-- 
wbr,
pluknet