Re: [PATCH] lib/string: sysfs_streq works case insensitively
From: Gioh Kim
Date: Wed Apr 28 2021 - 03:32:42 EST
On Wed, Apr 28, 2021 at 8:42 AM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
>
>
>
> On Wednesday, April 28, 2021, Gioh Kim <gi-oh.kim@xxxxxxxxx> wrote:
>>
>> On Mon, Apr 12, 2021 at 1:33 PM Gioh Kim <gi-oh.kim@xxxxxxxxx> wrote:
>> >
>> > As the name shows, it checks the strings inputed from sysfs.
>> > It should work for both case-sensitive filesystem and
>> > case-insensitive filesystem. Therefore sysfs_streq should work
>> > case-insensitively.
>> >
>> > Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxx>
>> > ---
>> > lib/string.c | 6 ++++--
>> > 1 file changed, 4 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/lib/string.c b/lib/string.c
>> > index 7548eb715ddb..d0914dffdaae 100644
>> > --- a/lib/string.c
>> > +++ b/lib/string.c
>> > @@ -688,7 +688,8 @@ EXPORT_SYMBOL(strsep);
>> > #endif
>> >
>> > /**
>> > - * sysfs_streq - return true if strings are equal, modulo trailing newline
>> > + * sysfs_streq - return true if strings are equal case-insentively,
>> > + * modulo trailing newline
>> > * @s1: one string
>> > * @s2: another string
>> > *
>> > @@ -696,10 +697,11 @@ EXPORT_SYMBOL(strsep);
>> > * NUL and newline-then-NUL as equivalent string terminations. It's
>> > * geared for use with sysfs input strings, which generally terminate
>> > * with newlines but are compared against values without newlines.
>> > + * And case does not matter for the sysfs input strings comparison.
>> > */
>> > bool sysfs_streq(const char *s1, const char *s2)
>> > {
>> > - while (*s1 && *s1 == *s2) {
>> > + while (*s1 && tolower(*s1) == tolower(*s2)) {
>> > s1++;
>> > s2++;
>> > }
>> > --
>> > 2.25.1
>> >
>>
>> Hi Andrew,
>>
>
> Are you sure it’s good change? Sysfs is used for an ABI and you are opening a can of worms. From me NAK to this change without a very good background description that tells why it is safe to do.
https://www.spinics.net/lists/kernel/msg3898123.html
My initial idea was making a new function: sysfs_streqcase.
Andrew and Greg suggested making sysfs_streq to be case-insensitive.
I would like to have a discussion about it.
>
>
>>
>> I changed sysfs_streq to be case-insensitive as you requested.
>> Is there any progress?
>
>
>
> --
> With Best Regards,
> Andy Shevchenko
>
>