Re: [PATCH] x86,boot: standardize strcmp()

From: Arjun Sreedharan
Date: Tue Mar 17 2015 - 10:13:41 EST


On 17 March 2015 at 13:16, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
>
> * Arjun Sreedharan <arjun024@xxxxxxxxx> wrote:
>
>> strcmp() is always expected to return 0 when args are
>> same, <0 when arg1 is lesser and >0 otherwise.
>> Previously strcmp("a","b") returned 1. Now it gives -1.
>
> I'd also add the following to the changelog:
>
> Until now this bug never triggered, because all uses for strcmp() in
> the boot code tested for nonzero:

On a related note, IMO strcmp() should return {-1,0,1} since many
programmers just expect this behavior. just my opinion.

Arjun Sreedharan

>
> triton:~/tip> git grep strcmp arch/x86/boot/
> arch/x86/boot/boot.h:int strcmp(const char *str1, const char *str2);
> arch/x86/boot/edd.c: if (!strcmp(eddarg, "skipmbr") || !strcmp(eddarg, "skip")) {
> arch/x86/boot/edd.c: else if (!strcmp(eddarg, "off"))
> arch/x86/boot/edd.c: else if (!strcmp(eddarg, "on"))
>
> should in the future strcmp() be used in a comparative way in the boot
> code, it might have led to (not so subtle) bugs.
>
> Thanks,
>
> Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/