On Tue, Nov 28, 2023 at 10:47 PM Alexei Starovoitov
[off-list ref] wrote:

On Tue, Nov 28, 2023 at 4:37 PM Song Liu [off-list ref] wrote:

quoted

+char digest[MAGIC_SIZE + sizeof(struct fsverity_digest) + SHA256_DIGEST_SIZE];

when vmlinux is built without CONFIG_FS_VERITY the above fails
in a weird way:
  CLNG-BPF [test_maps] test_sig_in_xattr.bpf.o
progs/test_sig_in_xattr.c:36:26: error: invalid application of
'sizeof' to an incomplete type 'struct fsverity_digest'
   36 | char digest[MAGIC_SIZE + sizeof(struct fsverity_digest) +
SHA256_DIGEST_SIZE];
      |                          ^     ~~~~~~~~~~~~~~~~~~~~~~~~

Is there a way to somehow print a hint during the build what
configs users need to enable to pass the build ?

Patch 5/6 added CONFIG_FS_VERITY to tools/testing/selftests/bpf/config.
This is a more general question for all required CONFIG_* specified in the
file (and the config files for other selftests).

In selftests/bpf/Makefile, we have logic to find vmlinux. We can add similar
logic to find .config used to build the vmlinux, and grep for each required
CONFIG_* from the .config file. Does this sound like a viable solution?

Thanks,
Song