On Wed, Jan 30, 2019 at 01:41:56PM +0100, Petr Mladek wrote: > Hmm, the error code is passed to the syscall, for example: > > + SYSCALL_DEFINE3(init_module > + load_module() > + do_init_module() > + do_one_initcall(mod->init); > > I am not sure if we are allowed to return -ENOTSUPP (-524). > It is defined in the internal include/linux/errno.h. There > is the following commnent: > > /* > * These should never be seen by user programs... > > > > I tried to find a better alternative and found: > > #define EOPNOTSUPP 95 /* Operation not supported on transport > endpoint */ > > > There is the following note in man errno: > > ENOTSUP Operation not supported (POSIX.1) > > EOPNOTSUPP Operation not supported on socket (POSIX.1) > (ENOTSUP and EOPNOTSUPP have the same value > on Linux, but according to POSIX.1 these error > values should be distinct.) > > And it looks that -EOPNOTSUPP is used widely in many subsystes (not > only network).
Yes, you are right. It's confusing that ENOTSUPP and ENOTSUP are not the same thing. EOPNOTSUPP sounds good. -- Josh
