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Wed, 03 Sep 2025 07:49:09 +0800 X-QQ-mid: xmsmtpt1756856949tpmm49ws0 Message-ID: X-QQ-XMAILINFO: MmpliBmRb3iCQR1bTXfLR1W02/D0qL61NJCdby35Lb/mvilCAmZEgHPfeIw1G8 pQ478bblMfWiK1MgML23lts38Y7fgTHwh8b6F0SEyaiEfDPiZX4i8BWpj4TpnDErSOB4gxmX5H1N 5kiIPCQwLYJ+YYJYgilHKkK09UAHC7BcLprxNNHVdwis58CCgNv0TKAJdcpkNuxDVyg0KmD8Oiey pqbBLCAXMNhWzlexB8fEe+RxKaD27ZYu2t+J7ZQeJ7b+EHErnZoT+PjFxSnAgFRXhaG/w+p5GEwd OhUB5F0FTLUDgtvu23+oej+6noLGPVeeQo3yHDRQWFEEhOH0TQxb7mgGWvQK7P0IX5eCbyO4aC0O 587V2aKvOthYgjYHhjttBLj6ZKYEBZovgm8InTNbpVrcmBp8h68ehqmbtKxIkmK5WBi4zwtFAEQc pkBbIiOenGAKi+cmW8RTqXDxztd1giNdz21kAJ90SdoLNYUZHYTf4/vtxEVJLpc5+PxhL+ZUPssJ gxAmO0tzaButi458PCfbCLuURgaMWOmKf7BSaPEKijngrhIecMATxwj6F//ZcHP8Tak4I6fU2y4n OofezAGaDwPlX+sNV+Sv2s7lH9ivUjpzXFGvrfAWPlyEWGle+ICtNt1QD0N9DauaIjCnFZQZRPmc d19CLhRDOKKevqWb3WBb72dBOmyvy4hLQCY3bYllGDWMjrYz6uFLnGA1mBOEfRmAsTQvJR3T2lIU n5qBTXFGkMpUXBVNaEFlYmNnY8gwsCZqN5koiujbZ8bglFxFCPKT4M7MZJyhO4b2AfmJV2fkyis7 EpJwN3mA5x+Zzw8PiIaDpx/QTXvr0otsPXrEFN0O8qMDlzC2vHaaqf5poaPQk/r2QJmnzTL1+waC 05G9SLcAIjQ4EQfBRchn0DrAeuYiWCZfMVTuj14JxM5tOvV6HGPCfCC9p5mbhBsocOppf9kwa9fn GtyTOHiny0V/y+oSXTnilA/A0GrAW2qo+aYWSf6dJvliQjpsM9wUfAiF6ElcbbALSr13HzZxs3u0 h1cpmXkzfmisz26mTO582A/tPDm1I= X-QQ-XMRINFO: Nq+8W0+stu50PRdwbJxPCL0= X-OQ-MSGID: <9322fc15-794d-42e2-89f6-9dba9f5068b4@foxmail.com> Date: Wed, 3 Sep 2025 07:49:09 +0800 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH bpf-next v3 1/2] bpf: add bpf_strcasecmp kfunc To: Yonghong Song , andrii@kernel.org, ast@kernel.org, vmalik@redhat.com Cc: Rong Tao , Daniel Borkmann , Martin KaFai Lau , Eduard Zingerman , Song Liu , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan , "open list:BPF [GENERAL] (Safe Dynamic Programs and Tools)" , open list , "open list:KERNEL SELFTEST FRAMEWORK" References: Content-Language: en-US From: Rong Tao In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 9/3/25 00:54, Yonghong Song wrote: > > > On 9/2/25 2:19 AM, Rong Tao wrote: >> From: Rong Tao >> >> bpf_strcasecmp() function performs same like bpf_strcmp() except >> ignoring >> the case of the characters. >> >> Signed-off-by: Rong Tao >> --- >>   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); >