It's necessary to call `bpf_probe_read` not only for pointers retrieved
from `PtRegs`, but also from BTF arguments.
`bpf_probe_read` might return an error, so the return type of `.arg()`
methods in contexts handling BTF arguments changes from `T` to
`Option<T>`. `None` is returned when `bpf_probe_read` call is not
successful.
Fixes: #542
Provide an `arg()` method in `RawTracepointArgs` wrapper of
`bpf_raw_tracepoint_args` and also in `RawTracepointContext`, so
it's directly available in raw tracepoint programs.
The methods and traits implemented here are unsafe. There is no
way to reliably check the number of available arguments, so
requesting a non-existing one leads to undefined behavior.
The const-assert crate doesn't even compile with stable rust, so we
shouldn't depend on it. Instead we replicate its functionality behind
cfg(unstable) which is set at build time based on the toolchain in use.
This API doesn't make sense as the max_entries needs to be set to the
number of online CPUs by the loader.
Signed-off-by: Dave Tucker <dave@dtucker.co.uk>
Michal Rostecki
Tamir Duberstein
dependabot[bot]
tamird
Zero King
Dave Tucker
Wouter Dullaert
tyrone-wu