On Fri, Apr 8, 2016 at 11:04 PM, Andrew Kelley <[email protected]> wrote: > The open syscall looks like this: > > SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, > mode) > > filename is a null terminated byte array. Null termination is one way > to handle lengths of byte arrays, but arguably a better way is to keep > track of the length in a separate field. Many programming languages > use pointer + length instead of null termination for various reasons. > > When it's time to make a syscall such as open, software which does not > have a null character at the end of byte arrays are forced to allocate > memory, do a memcpy, insert a null byte, perform the open syscall, > then deallocate the memory.
In many cases, it's possible to just add the NUL byte instead. > What are the chances that in the future, Linux will have alternate > syscalls which accept byte array parameters where one can pass the > length of the byte array explicitly instead of using a null byte? 0% chances. Amount of PITA to make that happen far outweighs possible benefits.
