Compile-time safety for referencing maps from user-space

[thomaseizinger]

It would be nice if there were a way of referencing a map by name in a way that is compile-time safe from user-space. For example, if I declare a map like this:

#[map]
static INT_ADDR_V4: PerCpuArray<[u8; 4]> = PerCpuArray::with_max_entries(1, 0);

I currently have to refer to this map from user-space as "INT_ADDR_V4". Nothing stops me from making a typo there. Arrays in particular are problematic here because they are 0-initialized, so the eBPF code can always access the data but it will just all be zeros.

Maybe the map macro could also export a const with the map name as a string? That would require the map to be defined a shared crate referenced from both user-space & the eBPF kernel. Not sure if that is possible?

[Brskt]

Do u mean like this ?

#[map(name = "ipv4_addr")]
static INT_ADDR_V4: PerCpuArray<[u8; 4]> = PerCpuArray::with_max_entries(1, 0);

If yes, u can already do it

[thomaseizinger]

I am aware of the name argument, unfortunately it doesn't accept consts but only string literals so the string is still duplicated in the userspace code that populates the map.