The log level implementation in b36cbc3eb8
was incomplete as the verifier could reject programs which exceeded
their instruction limits within logging statements. This commit
addresses this issue by making the log level static variable immutable
(s.t. the compiler puts it in a read-only section) and adds an
additional test which the verifier will reject as an infinite loop iff
it is unable to detect that the static variable would otherwise allow
the logging.
Change FromRawTracepointArgs::arg to return T rather than *const T which
seems to have been returning a dangling pointer.
Arguably this is not strictly necessary; edition 2024 seems to be
focused on increased strictness around unsafe code which doesn't unlock
new functionality for our users. That said, this work revealed an
apparent bug (see above) that we wouldn't otherwise catch due to
allow-by-default lints.
Fixes#1132.
Note that this change does not add support in the public API for kprobes
or tracepoints, but it's a trivial matter of plumbing.
Along the way, the Uprobe::attach API is cleaned up to make the
attachment location more coherent. The logic being: if we're going to be
breaking the API anyway, may as well clean it up a bit.
Furthermore, the aya::sys::bpf_link_attach function is cleaned up by
properly modeling the the union in the final field with a rust enum.
IP address types are available in `core`, so they can be used also in
eBPF programs. This change adds support of these types in aya-log.
* Add implementation of `WriteTuBuf` to these types.
* Support these types in `Ipv4Formatter` and `Ipv6Formatter`.
* Support them with `DisplayHint::Ip`.
* Add support for formatting `[u8; 4]`, to be able to handle
`Ipv4Addr::octets`.
And BpfLoader to EbpfLoader.
This also adds type aliases to preserve the use of the old names, making
updating to a new Aya release less of a burden. These aliases are marked
as deprecated since we'll likely remove them in a later release.
Signed-off-by: Dave Tucker <dave@dtucker.co.uk>
Some of these functions fail to compile when not inlined, so we should
be explicit.
Before deciding on this approach I tried various ways of making all
these functions #[inline(never)] to save instructions but I ran into
blockers:
- These functions currently return Result, which is a structure. This is
not permitted in BPF.
- I tried inventing a newtype that is a #[repr(transparent)] wrapper of
u16, and having these functions return that; however it seems that
even if the object code is legal, the verifier will reject such
functions because the BTF (if present, and it was in my local
experiments) would indicate that the return is a structure.
- I tried having these functions return a plain u16 where 0 means error,
but the verifier still rejected the BTF because the receiver (even if
made into &self) is considered a structure, and forbidden.
We can eventually overcome these problems by "lying" in our BTF once
support for it matures in the bpf-linker repo (e.g. Option<NonZeroU16>
should be perfectly legal as it is guaranteed to be word-sized), but we
aren't there yet, and this is the safest thing we can do for now.
In release, the trigger functions were being optimized out and the
tests did not work. Use core::hint::black_box to ensure that the
functions are not optimized out. Also, run these integration tests
in CI to ensure that we don't regress.
"integration tests" as defined by Cargo produce a binary per file in the
tests directory. This is really not what we want and has a number of
downsides, but the main one is binary size.
Before:
tamird@pc:~/src/aya$ cargo xtask build-integration-test | xargs ls -lah
Finished dev [unoptimized + debuginfo] target(s) in 0.05s
Running `target/debug/xtask build-integration-test`
Compiling integration-test v0.1.0 (/home/tamird/src/aya/test/integration-test)
Finished dev [unoptimized + debuginfo] target(s) in 0.68s
-rwxrwxr-x 1 tamird tamird 34M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/bpf_probe_read-e03eb905a5e6209c
-rwxrwxr-x 1 tamird tamird 35M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/btf_relocations-57a4fbb38bf06064
-rwxrwxr-x 1 tamird tamird 31M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/elf-98b7a32d6d04effb
-rwxrwxr-x 1 tamird tamird 6.9M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/integration_test-0dd55ce96bfdad77
-rwxrwxr-x 1 tamird tamird 34M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/load-0718562e85b86d03
-rwxrwxr-x 1 tamird tamird 40M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/log-dbf355f9ea34068a
-rwxrwxr-x 1 tamird tamird 36M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/rbpf-89a1bb848fa5cc3c
-rwxrwxr-x 1 tamird tamird 34M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/relocations-cfe655c3bb413d8b
-rwxrwxr-x 1 tamird tamird 34M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/smoke-ccd3974180a3fd29
After:
tamird@pc:~/src/aya$ cargo xtask build-integration-test | xargs ls -lah
Finished dev [unoptimized + debuginfo] target(s) in 0.05s
Running `target/debug/xtask build-integration-test`
Compiling integration-test v0.1.0 (/home/tamird/src/aya/test/integration-test)
Finished dev [unoptimized + debuginfo] target(s) in 0.90s
-rwxrwxr-x 1 tamird tamird 47M Jul 12 15:21 /home/tamird/src/aya/target/debug/deps/integration_test-0dd55ce96bfdad77
Since we plan to run these tests in a VM, copying 10x fewer bytes seems
like a win.
This doesn't add any value; use `cargo build --tests` with
`--message-format=json` instead; parse the output using `cargo_metadata`
to discover the location of the test binary.
Move test/integration-test/src/tests -> test/integration-test/tests to
conform to
https://doc.rust-lang.org/book/ch11-03-test-organization.html#integration-tests.
Tamir Duberstein
Addison Crump
Andrew Werner
Michal Rostecki
Dave Tucker
Alessandro Decina