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Re: [Libvir] PATCH 1/4: QEMU driver char device support



On Thu, Apr 24, 2008 at 10:01:29PM +0200, Jim Meyering wrote:
> "Daniel P. Berrange" <berrange redhat com> wrote:
> >      static const char needle[] = "char device redirected to";
> >      char *tmp;
> >
> > -    if (!(tmp = strstr(haystack, needle)))
> > +    /* First look for our magic string */
> > +    if (!(tmp = strstr(haystack + *offset, needle)))
> >          return -1;
> >
> > +    /* Grab all the trailing data */
> >      strncpy(path, tmp+sizeof(needle), pathmax-1);
> 
> That should be sizeof(needle)-1.
> Otherwise, if someone nasty gave you input ending with
> "char device redirected to", the strncpy above would start
> reading just past the NUL at the end of "haystack".

Fixed this.

> >      path[pathmax-1] = '\0';
> >
> > -    while (*path) {
> > -        /*
> > -         * The monitor path ends at first whitespace char
> > -         * so lets search for it & NULL terminate it there
> > -         */
> > -        if (isspace(*path)) {
> > -            *path = '\0';
> > +    /*
> > +     * And look for first whitespace character and nul terminate
> > +     * to mark end of the pty path
> > +     */
> > +    tmp = path;
> > +    while (*tmp) {
> > +        if (isspace(*tmp)) {
> 
> Since "tmp" has type "char", this causes trouble in an environment
> where "char" is a signed type.  When *tmp is larger than 127, it gets
> sign-extended, and isspace can misbehave on the large negative number
> (isspace is not defined for such values).  Instead, do it like this:
> 
>       if (isspace(*(unsigned char *)tmp)) {
> 
> or better, using the to_uchar function (from coreutils):
> 
>       if (isspace(to_uchar(tmp))) {

Fixed this when merging with your to_uchar() changes.

Dan.
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