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

[Daniel P . Berrangé]

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.

> +    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
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