On Mon, May 24, 2021 at 1:35 PM Stanislav Fomichev <sdf@xxxxxxxxxx> wrote: > > On Mon, May 24, 2021 at 12:19 PM Andrii Nakryiko > <andrii.nakryiko@xxxxxxxxx> wrote: > > > > On Sun, May 23, 2021 at 11:36 PM John Fastabend > > <john.fastabend@xxxxxxxxx> wrote: > > > > > > Andrii Nakryiko wrote: > > > > Implement error reporting changes discussed in "Libbpf: the road to v1.0" > > > > ([0]) document. > > > > > > > > Libbpf gets a new API, libbpf_set_strict_mode() which accepts a set of flags > > > > that turn on a set of libbpf 1.0 changes, that might be potentially breaking. > > > > It's possible to opt-in into all current and future 1.0 features by specifying > > > > LIBBPF_STRICT_ALL flag. > > > > > > > > When some of the 1.0 "features" are requested, libbpf APIs might behave > > > > differently. In this patch set a first set of changes are implemented, all > > > > related to the way libbpf returns errors. See individual patches for details. > > > > > > > > Patch #1 adds a no-op libbpf_set_strict_mode() functionality to enable > > > > updating selftests. > > > > > > > > Patch #2 gets rid of all the bad code patterns that will break in libbpf 1.0 > > > > (exact -1 comparison for low-level APIs, direct IS_ERR() macro usage to check > > > > pointer-returning APIs for error, etc). These changes make selftest work in > > > > both legacy and 1.0 libbpf modes. Selftests also opt-in into 100% libbpf 1.0 > > > > mode to automatically gain all the subsequent changes, which will come in > > > > follow up patches. > > > > > > > > Patch #3 streamlines error reporting for low-level APIs wrapping bpf() syscall. > > > > > > > > Patch #4 streamlines errors for all the rest APIs. > > > > > > > > Patch #5 ensures that BPF skeletons propagate errors properly as well, as > > > > currently on error some APIs will return NULL with no way of checking exact > > > > error code. > > > > > > > > [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY > > > > > > > > Andrii Nakryiko (5): > > > > libbpf: add libbpf_set_strict_mode() API to turn on libbpf 1.0 > > > > behaviors > > > > selftests/bpf: turn on libbpf 1.0 mode and fix all IS_ERR checks > > > > libbpf: streamline error reporting for low-level APIs > > > > libbpf: streamline error reporting for high-level APIs > > > > bpftool: set errno on skeleton failures and propagate errors > > > > > > > > > > LGTM for the series, > > > > > > Acked-by: John Fastabend <john.fastabend@xxxxxxxxx> > > > > Thanks, John! > > > > Toke, Stanislav, you cared about these aspects of libbpf 1.0 (by > > commenting on the doc itself), do you mind also taking a brief look > > and letting me know if this works for your use cases? Thanks! > > I took a quick look earlier today and everything looks good, thanks! Great, thanks for looking. > I'll try to enable strict mode in our codebase in the coming weeks to > see how it goes. Keep in mind, if you do libbpf_set_strict_mode(LIBBPF_STRICT_ALL) you are automatically opting in for all the future "features", so for production you might want to go conservative and start with specifying explicitly LIBBPF_STRICT_DIRECT_ERRS | LIBBPF_STRICT_CLEAN_PTRS, and then add more as you check that your code will handle new changes.
