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

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

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
>