On 6/23/25 18:42, Alexei Starovoitov wrote: > On Mon, Jun 23, 2025 at 6:48 AM Viktor Malik <vmalik@xxxxxxxxxx> wrote: >> >> +/* Kfuncs for string operations. > > Pls use normal kernel style comments instead of old networking. > That's what we prefer for all new code. > >> + * >> + * Since strings are not necessarily %NUL-terminated, we cannot directly call >> + * in-kernel implementations. Instead, we open-code the implementations using >> + * __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 > > Here -1 and 1 return values are probably ok, since they match > traditional strcmp. > >> + * * %-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_strnchr - Find a character in a length limited string >> + * @s__ign: The string to be searched >> + * @count: The number of characters to be searched >> + * @c: The character to search for >> + * >> + * Note that the %NUL-terminator is considered part of the string, and can >> + * be searched for. >> + * >> + * Return: >> + * * >=0 - Index of the first occurrence of @c within @s__ign >> + * * %-1 - @c not found in the first @count characters of @s__ign >> + * * %-EFAULT - Cannot read @s__ign >> + * * %-E2BIG - @s__ign is too large >> + * * %-ERANGE - @s__ign is outside of kernel address space >> + */ > > but here and in a few other places returning -1 is effectively > returning -EPERM for "not found". > Which is odd. > Maybe let's return -ENOENT instead ? Yes, that was my other alternative, I'll change it. Thanks.
