On 9/3/25 00:54, Yonghong Song wrote:

On 9/2/25 2:19 AM, Rong Tao wrote:

...

From: Rong Tao rongtao@cestc.cn

bpf_strcasecmp() function performs same like bpf_strcmp() except ignoring the case of the characters.

Signed-off-by: Rong Tao rongtao@cestc.cn

kernel/bpf/helpers.c | 68 +++++++++++++++++++++++++++++++-------------   1 file changed, 48 insertions(+), 20 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 401b4932cc49..238fd992c786 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3349,45 +3349,72 @@ __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, const char *s2, bool ignore_case)

The function __bpf_strcasecmp should be a static function.

Thanks a lot, I just add 'static' and tested it, submit V4, please review.

Rong Tao

...

{       char c1, c2;       int i;   -    if (!copy_from_kernel_nofault_allowed(s1__ign, 1) || -        !copy_from_kernel_nofault_allowed(s2__ign, 1)) { +    if (!copy_from_kernel_nofault_allowed(s1, 1) || +        !copy_from_kernel_nofault_allowed(s2, 1)) {           return -ERANGE;       }         guard(pagefault)();       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); +        __get_kernel_nofault(&c1, s1, char, err_out); +        __get_kernel_nofault(&c2, s2, char, err_out); +        if (ignore_case) { +            c1 = tolower(c1); +            c2 = tolower(c2); +        }           if (c1 != c2)               return c1 < c2 ? -1 : 1;           if (c1 == '\0')               return 0; -        s1__ign++; -        s2__ign++; +        s1++; +        s2++;       }       return -E2BIG;   err_out:       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);