Re: [PATCH] hw/core/qdev-properties-system: Rewrite set_pci_host_devaddr using GLib

[Philippe Mathieu-Daudé]

On 10/13/20 12:07 PM, Daniel P. Berrangé wrote:
> On Tue, Oct 13, 2020 at 12:03:15PM +0200, Philippe Mathieu-Daudé wrote:
> > set_pci_host_devaddr() is hard to follow, thus bug-prone.
> > We indeed introduced a bug in commit bccb20c49df, as the
> > same line might be used to parse a bus (up to 0xff) or a
> > slot (up to 0x1f). Instead of making things worst, rewrite
> > using g_strsplit().
> >
> > Fixes: bccb20c49df ("Use qemu_strtoul() in set_pci_host_devaddr()")
> > Reported-by: Klaus Herman <kherman@inbox.lv>
> > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> > ---
> >   hw/core/qdev-properties-system.c | 61 ++++++++++++++------------------
> >   1 file changed, 27 insertions(+), 34 deletions(-)
> >
> > diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
> > index 49bdd125814..e6e081efd58 100644
> > --- a/hw/core/qdev-properties-system.c
> > +++ b/hw/core/qdev-properties-system.c
> > @@ -878,11 +878,11 @@ static void set_pci_host_devaddr(Object *obj, Visitor *v, 
> > const char *name,
> >       DeviceState *dev = DEVICE(obj);
> >       Property *prop = opaque;
> >       PCIHostDeviceAddress *addr = qdev_get_prop_ptr(dev, prop);
> > -    char *str, *p;
> > -    const char *e;
> > +    g_autofree char *str = NULL;
> > +    g_autofree char **col_s0 = NULL;
> > +    g_autofree char **dot_s = NULL;
>
> These free the array, but not the array elements.
>
> You need to use
>
>     g_auto(GStrv) col_s0 = NULL
>
> GStrv is a typedef for char **, that exists solely so that there is
> a typename against which g_auto can be used.

Ah I have been wondering how that part works.

Thanks, I'll fix.

> > +    char **col_s;
> >       unsigned long val;
> > -    unsigned long dom = 0, bus = 0;
> > -    unsigned int slot = 0, func = 0;
> >   
> >       if (dev->realized) {
> >           qdev_prop_set_after_realize(dev, name, errp);
> > @@ -893,57 +893,50 @@ static void set_pci_host_devaddr(Object *obj, Visitor *v, 
> > const char *name,
> >           return;
> >       }
> >   
> > -    p = str;
> > -    if (qemu_strtoul(p, &e, 16, &val) < 0 || val > 0xffff || e == p) {
> > +    col_s = col_s0 = g_strsplit(str, ":", 3);
> > +    if (!col_s || !col_s[0] || !col_s[1]) {
> >           goto inval;
> >       }
> > -    if (*e != ':') {
> > -        goto inval;
> > -    }
> > -    bus = val;
> >   
> > -    p = (char *)e + 1;
> > -    if (qemu_strtoul(p, &e, 16, &val) < 0 || val > 0x1f || e == p) {
> > -        goto inval;
> > -    }
> > -    if (*e == ':') {
> > -        dom = bus;
> > -        bus = val;
> > -        p = (char *)e + 1;
> > -        if (qemu_strtoul(p, &e, 16, &val) < 0 || val > 0x1f || e == p) {
> > +    /* domain */
> > +    if (col_s[2]) {
> > +        if (qemu_strtoul(col_s[0], NULL, 16, &val) < 0 || val > 0xffff) {
> >               goto inval;
> >           }
> > +        addr->domain = val;
> > +        col_s++;
> > +    } else {
> > +        addr->domain = 0;
> >       }
> > -    slot = val;
> >   
> > -    if (*e != '.') {
> > +    /* bus */
> > +    if (qemu_strtoul(col_s[0], NULL, 16, &val) < 0 || val > 0xff) {
> >           goto inval;
> >       }
> > -    p = (char *)e + 1;
> > -    if (qemu_strtoul(p, &e, 10, &val) < 0 || val > 7 || e == p) {
> > -        goto inval;
> > -    }
> > -    func = val;
> > +    addr->bus = val;
> >   
> > -    if (bus > 0xff) {
> > +    /* <slot>.<func> */
> > +    dot_s = g_strsplit(col_s[1], ".", 2);
> > +    if (!dot_s || !dot_s[0] || !dot_s[1]) {
> >           goto inval;
> >       }
> >   
> > -    if (*e) {
> > +    /* slot */
> > +    if (qemu_strtoul(dot_s[0], NULL, 16, &val) < 0 || val > 0x1f) {
> >           goto inval;
> >       }
> > +    addr->slot = val;
> >   
> > -    addr->domain = dom;
> > -    addr->bus = bus;
> > -    addr->slot = slot;
> > -    addr->function = func;
> > +    /* func */
> > +    if (qemu_strtoul(dot_s[1], NULL, 10, &val) < 0 || val > 7) {
> > +        goto inval;
> > +    }
> > +    addr->function = val;
> >   
> > -    g_free(str);
> >       return;
> >   
> >   inval:
> >       error_set_from_qdev_prop_error(errp, EINVAL, dev, prop, str);
> > -    g_free(str);
> >   }
> >   
> >   const PropertyInfo qdev_prop_pci_host_devaddr = {
> > --
> > 2.26.2
>
> Regards,
> Daniel