Looks correct to me. The value returned by get_ucomnames() is only
passed to find_ucom() where it is checked against NULL.
aphekz, if you can confirm this works for you I can commit.
.... Ken
"Theo de Raadt" <dera...@openbsd.org> writes:
> Yes, this code should not fail in that circumstance. It should silently
> carry on.
>
> Note the code:
>
> #if NUCOM > 0
> case HW_UCOMNAMES: {
>
> If the kernel has no USB com, the sysctl code is disabled. That is why
> it MUST silently carry on.
>
> But your bug report is incomplete. Where is the full dmesg for the machine
> where this happened?
>
> Probably this diff.
>
> Index: cu.c
> ===================================================================
> RCS file: /cvs/src/usr.bin/cu/cu.c,v
> diff -u -p -u -r1.30 cu.c
> --- cu.c 21 Dec 2023 11:25:38 -0000 1.30
> +++ cu.c 10 Feb 2024 02:37:32 -0000
> @@ -488,13 +488,13 @@ get_ucomnames(void)
> size = 0;
> for (;;) {
> if (sysctl(mib, 2, NULL, &size, NULL, 0) == -1 || size == 0)
> - err(1, "hw.ucomnames");
> + return NULL;
> if ((names = realloc(names, size)) == NULL)
> err(1, NULL);
> if (sysctl(mib, 2, names, &size, NULL, 0) != -1)
> break;
> if (errno != ENOMEM)
> - err(1, "hw.ucomnames");
> + return NULL;
> }
> return names;
> }
>
> The code that uses the return value from get_ucomnames() may be safe.
> I'm rushed, don't want to burn dinner.
>
>
> aphekz <aph...@kroczynski.net> wrote:
>
>> hi
>>
>> ~ > cu -l cua00 -s 115200
>> (on -stable) quits with an error
>> cu: hw.ucomnames: Operation not supported
>>
>> as there is only
>> com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
>> and no any ucom devices on that machine
>>
>> so as below there is no hw.ucomnames value
>> ~ > sysctl hw.ucomnames
>> sysctl: hw.ucomnames: value is not available
>>
>> seems one of last changes
>> src/usr.bin/cu/cu.c 2023/10/02 1.29
>>
>> in
>> char *
>> get_ucomnames(void)
>> ...
>> if (sysctl(mib, 2, NULL, &size, NULL, 0) == -1 || size == 0)
>> err(1, "hw.ucomnames");
>>
>> makes problem in my case.
>>
>> shouldn't we have
>> - err(1, "hw.ucomnames");
>> + break;
>>
>> as i'm not experienced enough to suggest diff (i might be missing sth)
>> so.. verify that please.
>>
>> aphekz
>>
--
.... Ken
