tree f8591cde74a9e6c302fa400b5bc734814d2b2736
parent cb974884b68b7b2001dfcd8f46c446c0ff8c6336
author David Benjamin <davidben@google.com> 1689366643 -0400
committer Boringssl LUCI CQ <boringssl-scoped@luci-project-accounts.iam.gserviceaccount.com> 1689709610 +0000

Support Android's "baremetal" target

This corresponds to the libcrypto_baremetal build target in Android,
which is an embedded-style platform that uses a subset of the bionic
libc. It will also, eventually, use getentropy for its PRNG.

As part of this, generalize the OPENSSL_TRUSTY exclusion for file BIOs
to OPENSSL_NO_FILESYSTEM. Upstream OpenSSL uses OPENSSL_NO_STDIO, but
that excludes all of FILE entirely. We already require FILE in quite a
few places (urandom.c, self_test.c) for writing to stderr, and FILE is
part of C standard library. So, let's tentatively say that we require
you have FILE and stderr.

Instead, OPENSSL_NO_FILESYSTEM is saying you don't have fopen. You're
still required to have the three std{in,out,err} FILEs, and given a
FILE, you need to allow the standard operations on it. (Possibly in
forms that always fail.)

To keep us honest, whenever a function is excluded, I've dropped it from
the header too, and followed callers up the chain. I have not attempted
to make the tests work when these are excluded. Later CLs in this series
will do the same for NO_SOCK and NO_POSIX_IO. This was a little tedious,
but not too bad.

(I assume we'll end up changing our minds on this a lot. For now, let's
try this.)

I haven't yet restored OPENSSL_RAND_TRUSTY or removed the OPENSSL_TRUSTY
ifdef on file.c. Having a separate CL makes it a bit easier to revert if
something goes wrong.

This depends on
https://android-review.googlesource.com/c/platform/bionic/+/2659335,
which fixes the header bionic uses for getentropy.

Bug: 629, b:291102972
Change-Id: Idd839cd3fa4253128de54bd1be7da261dbcdeb7c
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/61726
Auto-Submit: David Benjamin <davidben@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
Commit-Queue: Bob Beck <bbe@google.com>