[PATCH bpf-next v3 1/2] bpf: add bpf_strcasecmp kfunc

[PATCH bpf-next v3 1/2] bpf: add bpf_strcasecmp kfunc

[Rong Tao]

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)
 {
 	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);
-- 
2.51.0

[PATCH bpf-next v3 2/2] selftests/bpf: Test kfunc bpf_strcasecmp

[Rong Tao]

From: Rong Tao <rongtao@cestc.cn>

Add testsuites for kfunc bpf_strcasecmp.

Signed-off-by: Rong Tao <rongtao@cestc.cn>
---
 tools/testing/selftests/bpf/prog_tests/string_kfuncs.c     | 1 +
 tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c | 6 ++++++
 tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c | 1 +
 tools/testing/selftests/bpf/progs/string_kfuncs_success.c  | 5 +++++
 4 files changed, 13 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c b/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
index 35af8044d059..4d66fad3c8bd 100644
--- a/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
+++ b/tools/testing/selftests/bpf/prog_tests/string_kfuncs.c
@@ -8,6 +8,7 @@
 
 static const char * const test_cases[] = {
 	"strcmp",
+	"strcasecmp",
 	"strchr",
 	"strchrnul",
 	"strnchr",
diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
index 53af438bd998..99d72c68f76a 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure1.c
@@ -31,6 +31,8 @@ char *invalid_kern_ptr = (char *)-1;
 /* Passing NULL to string kfuncs (treated as a userspace ptr) */
 SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_null1(void *ctx) { return bpf_strcmp(NULL, "hello"); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strcmp_null2(void *ctx) { return bpf_strcmp("hello", NULL); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_null1(void *ctx) { return bpf_strcasecmp(NULL, "HELLO"); }
+SEC("syscall")  __retval(USER_PTR_ERR)int test_strcasecmp_null2(void *ctx) { return bpf_strcasecmp("HELLO", NULL); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strchr_null(void *ctx) { return bpf_strchr(NULL, 'a'); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strchrnul_null(void *ctx) { return bpf_strchrnul(NULL, 'a'); }
 SEC("syscall")  __retval(USER_PTR_ERR)int test_strnchr_null(void *ctx) { return bpf_strnchr(NULL, 1, 'a'); }
@@ -49,6 +51,8 @@ SEC("syscall")  __retval(USER_PTR_ERR)int test_strnstr_null2(void *ctx) { return
 /* Passing userspace ptr to string kfuncs */
 SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr1(void *ctx) { return bpf_strcmp(user_ptr, "hello"); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strcmp_user_ptr2(void *ctx) { return bpf_strcmp("hello", user_ptr); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr1(void *ctx) { return bpf_strcasecmp(user_ptr, "HELLO"); }
+SEC("syscall") __retval(USER_PTR_ERR) int test_strcasecmp_user_ptr2(void *ctx) { return bpf_strcasecmp("HELLO", user_ptr); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strchr_user_ptr(void *ctx) { return bpf_strchr(user_ptr, 'a'); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strchrnul_user_ptr(void *ctx) { return bpf_strchrnul(user_ptr, 'a'); }
 SEC("syscall") __retval(USER_PTR_ERR) int test_strnchr_user_ptr(void *ctx) { return bpf_strnchr(user_ptr, 1, 'a'); }
@@ -69,6 +73,8 @@ SEC("syscall") __retval(USER_PTR_ERR) int test_strnstr_user_ptr2(void *ctx) { re
 /* Passing invalid kernel ptr to string kfuncs should always return -EFAULT */
 SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault1(void *ctx) { return bpf_strcmp(invalid_kern_ptr, "hello"); }
 SEC("syscall") __retval(-EFAULT) int test_strcmp_pagefault2(void *ctx) { return bpf_strcmp("hello", invalid_kern_ptr); }
+SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault1(void *ctx) { return bpf_strcasecmp(invalid_kern_ptr, "HELLO"); }
+SEC("syscall") __retval(-EFAULT) int test_strcasecmp_pagefault2(void *ctx) { return bpf_strcasecmp("HELLO", invalid_kern_ptr); }
 SEC("syscall") __retval(-EFAULT) int test_strchr_pagefault(void *ctx) { return bpf_strchr(invalid_kern_ptr, 'a'); }
 SEC("syscall") __retval(-EFAULT) int test_strchrnul_pagefault(void *ctx) { return bpf_strchrnul(invalid_kern_ptr, 'a'); }
 SEC("syscall") __retval(-EFAULT) int test_strnchr_pagefault(void *ctx) { return bpf_strnchr(invalid_kern_ptr, 1, 'a'); }
diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c b/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
index 89fb4669b0e9..e41cc5601994 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_failure2.c
@@ -7,6 +7,7 @@
 char long_str[XATTR_SIZE_MAX + 1];
 
 SEC("syscall") int test_strcmp_too_long(void *ctx) { return bpf_strcmp(long_str, long_str); }
+SEC("syscall") int test_strcasecmp_too_long(void *ctx) { return bpf_strcasecmp(long_str, long_str); }
 SEC("syscall") int test_strchr_too_long(void *ctx) { return bpf_strchr(long_str, 'b'); }
 SEC("syscall") int test_strchrnul_too_long(void *ctx) { return bpf_strchrnul(long_str, 'b'); }
 SEC("syscall") int test_strnchr_too_long(void *ctx) { return bpf_strnchr(long_str, sizeof(long_str), 'b'); }
diff --git a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
index 46697f381878..67830456637b 100644
--- a/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
+++ b/tools/testing/selftests/bpf/progs/string_kfuncs_success.c
@@ -12,6 +12,11 @@ char str[] = "hello world";
 /* Functional tests */
 __test(0) int test_strcmp_eq(void *ctx) { return bpf_strcmp(str, "hello world"); }
 __test(1) int test_strcmp_neq(void *ctx) { return bpf_strcmp(str, "hello"); }
+__test(0) int test_strcasecmp_eq1(void *ctx) { return bpf_strcasecmp(str, "hello world"); }
+__test(0) int test_strcasecmp_eq2(void *ctx) { return bpf_strcasecmp(str, "HELLO WORLD"); }
+__test(0) int test_strcasecmp_eq3(void *ctx) { return bpf_strcasecmp(str, "HELLO world"); }
+__test(1) int test_strcasecmp_neq1(void *ctx) { return bpf_strcasecmp(str, "hello"); }
+__test(1) int test_strcasecmp_neq2(void *ctx) { return bpf_strcasecmp(str, "HELLO"); }
 __test(1) int test_strchr_found(void *ctx) { return bpf_strchr(str, 'e'); }
 __test(11) int test_strchr_null(void *ctx) { return bpf_strchr(str, '\0'); }
 __test(-ENOENT) int test_strchr_notfound(void *ctx) { return bpf_strchr(str, 'x'); }
-- 
2.51.0

Re: [PATCH bpf-next v3 1/2] bpf: add bpf_strcasecmp kfunc

[Viktor Malik]

On 9/2/25 11:19, 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>

For the series:

Acked-by: Viktor Malik <vmalik@redhat.com>

> ---
>  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)
>  {
>  	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);

Re: [PATCH bpf-next v3 1/2] bpf: add bpf_strcasecmp kfunc

[Yonghong Song]

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.

>   {
>   	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);

Re: [PATCH bpf-next v3 1/2] bpf: add bpf_strcasecmp kfunc

[Rong Tao]

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);
>