On Wed, Dec 8, 2021 at 12:04 PM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> > > > +static const char *reg_type_str(enum bpf_reg_type type)
> > > > +{
> > > > + static const char * const str[] = {
> > > > + [NOT_INIT] = "?",
> > > > + [SCALAR_VALUE] = "inv",
> > > > + [PTR_TO_CTX] = "ctx",
> > > > + [CONST_PTR_TO_MAP] = "map_ptr",
> > > > + [PTR_TO_MAP_VALUE] = "map_value",
> > > > + [PTR_TO_STACK] = "fp",
> > > > + [PTR_TO_PACKET] = "pkt",
> > > > + [PTR_TO_PACKET_META] = "pkt_meta",
> > > > + [PTR_TO_PACKET_END] = "pkt_end",
> > > > + [PTR_TO_FLOW_KEYS] = "flow_keys",
> > > > + [PTR_TO_SOCKET] = "sock",
> > > > + [PTR_TO_SOCK_COMMON] = "sock_common",
> > > > + [PTR_TO_TCP_SOCK] = "tcp_sock",
> > > > + [PTR_TO_TP_BUFFER] = "tp_buffer",
> > > > + [PTR_TO_XDP_SOCK] = "xdp_sock",
> > > > + [PTR_TO_BTF_ID] = "ptr_",
> > > > + [PTR_TO_PERCPU_BTF_ID] = "percpu_ptr_",
> > > > + [PTR_TO_MEM] = "mem",
> > > > + [PTR_TO_RDONLY_BUF] = "rdonly_buf",
> > > > + [PTR_TO_RDWR_BUF] = "rdwr_buf",
> > > > + [PTR_TO_FUNC] = "func",
> > > > + [PTR_TO_MAP_KEY] = "map_key",
> > > > + };
> > > > +
> > > > + return str[base_type(type)];
> > >
> > > well... now we lose the "_or_null" part, that can be pretty important.
> > > Same will happen with RDONLY flag, right?
> > >
> > > What can we do about that?
> > >
> >
> > We can format the string into a global buffer and return the buffer to
> > the caller. A little overhead on string formatting.
>
> Can't use global buffer, because multiple BPF verifications can
> proceed at the same time.
I think reg_type_str() can still return a const char string
with flags.
It's not going to be a direct str[base_type(type)]; of course.
The str[] would be different.
If that doesn't work out we can try:
s/verbose(,"%s", reg_type_str[])
/verbose(, "%s%s", reg_type_str(), reg_type_flags_str())
