On 9/2/25 08:17, Rong Tao wrote:
> From: Rong Tao <[email protected]>
>
> bpf_strcasecmp() function performs same like bpf_strcmp() except ignoring
> the case of the characters.
>
> Signed-off-by: Rong Tao <[email protected]>
> ---
> kernel/bpf/helpers.c | 56 +++++++++++++++++++++++++++++++++-----------
> 1 file changed, 42 insertions(+), 14 deletions(-)
>
> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> index 401b4932cc49..e807a708e5fc 100644
> --- a/kernel/bpf/helpers.c
> +++ b/kernel/bpf/helpers.c
> @@ -3349,20 +3349,7 @@ __bpf_kfunc void __bpf_trap(void)
> * __get_kernel_nofault instead of plain dereference to make them safe.
> */
>
> -/**
> - * bpf_strcmp - Compare two strings
> - * @s1__ign: One string
> - * @s2__ign: Another string
> - *
> - * Return:
> - * * %0 - Strings are equal
> - * * %-1 - @s1__ign is smaller
> - * * %1 - @s2__ign is smaller
> - * * %-EFAULT - Cannot read one of the strings
> - * * %-E2BIG - One of strings is too large
> - * * %-ERANGE - One of strings is outside of kernel address space
> - */
> -__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign)
> +int __bpf_strcasecmp(const char *s1__ign, const char *s2__ign, bool
> ignore_case)
No need to use the `__ign` suffix here.
Otherwise LGTM. I guess that it could be useful in some applications.
Viktor
> {
> char c1, c2;
> int i;
> @@ -3376,6 +3363,10 @@ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const
> char *s2__ign)
> for (i = 0; i < XATTR_SIZE_MAX; i++) {
> __get_kernel_nofault(&c1, s1__ign, char, err_out);
> __get_kernel_nofault(&c2, s2__ign, char, err_out);
> + if (ignore_case) {
> + c1 = tolower(c1);
> + c2 = tolower(c2);
> + }
> if (c1 != c2)
> return c1 < c2 ? -1 : 1;
> if (c1 == '\0')
> @@ -3388,6 +3379,42 @@ __bpf_kfunc int bpf_strcmp(const char *s1__ign, const
> char *s2__ign)
> return -EFAULT;
> }
>
> +/**
> + * bpf_strcmp - Compare two strings
> + * @s1__ign: One string
> + * @s2__ign: Another string
> + *
> + * Return:
> + * * %0 - Strings are equal
> + * * %-1 - @s1__ign is smaller
> + * * %1 - @s2__ign is smaller
> + * * %-EFAULT - Cannot read one of the strings
> + * * %-E2BIG - One of strings is too large
> + * * %-ERANGE - One of strings is outside of kernel address space
> + */
> +__bpf_kfunc int bpf_strcmp(const char *s1__ign, const char *s2__ign)
> +{
> + return __bpf_strcasecmp(s1__ign, s2__ign, false);
> +}
> +
> +/**
> + * bpf_strcasecmp - Compare two strings, ignoring the case of the characters
> + * @s1__ign: One string
> + * @s2__ign: Another string
> + *
> + * Return:
> + * * %0 - Strings are equal
> + * * %-1 - @s1__ign is smaller
> + * * %1 - @s2__ign is smaller
> + * * %-EFAULT - Cannot read one of the strings
> + * * %-E2BIG - One of strings is too large
> + * * %-ERANGE - One of strings is outside of kernel address space
> + */
> +__bpf_kfunc int bpf_strcasecmp(const char *s1__ign, const char *s2__ign)
> +{
> + return __bpf_strcasecmp(s1__ign, s2__ign, true);
> +}
> +
> /**
> * bpf_strnchr - Find a character in a length limited string
> * @s__ign: The string to be searched
> @@ -3832,6 +3859,7 @@ BTF_ID_FLAGS(func, bpf_iter_dmabuf_destroy,
> KF_ITER_DESTROY | KF_SLEEPABLE)
> #endif
> BTF_ID_FLAGS(func, __bpf_trap)
> BTF_ID_FLAGS(func, bpf_strcmp);
> +BTF_ID_FLAGS(func, bpf_strcasecmp);
> BTF_ID_FLAGS(func, bpf_strchr);
> BTF_ID_FLAGS(func, bpf_strchrnul);
> BTF_ID_FLAGS(func, bpf_strnchr);
