freebsd-dev/tests
Andrew Turner b3c0d957a2 Add support for the Clang Coverage Sanitizer in the kernel (KCOV).
When building with KCOV enabled the compiler will insert function calls
to probes allowing us to trace the execution of the kernel from userspace.
These probes are on function entry (trace-pc) and on comparison operations
(trace-cmp).

Userspace can enable the use of these probes on a single kernel thread with
an ioctl interface. It can allocate space for the probe with KIOSETBUFSIZE,
then mmap the allocated buffer and enable tracing with KIOENABLE, with the
trace mode being passed in as the int argument. When complete KIODISABLE
is used to disable tracing.

The first item in the buffer is the number of trace event that have
happened. Userspace can write 0 to this to reset the tracing, and is
expected to do so on first use.

The format of the buffer depends on the trace mode. When in PC tracing just
the return address of the probe is stored. Under comparison tracing the
comparison type, the two arguments, and the return address are traced. The
former method uses on entry per trace event, while the later uses 4. As
such they are incompatible so only a single mode may be enabled.

KCOV is expected to help fuzzing the kernel, and while in development has
already found a number of issues. It is required for the syzkaller system
call fuzzer [1]. Other kernel fuzzers could also make use of it, either
with the current interface, or by extending it with new modes.

A man page is currently being worked on and is expected to be committed
soon, however having the code in the kernel now is useful for other
developers to use.

[1] https://github.com/google/syzkaller

Submitted by:	Mitchell Horne <mhorne063@gmail.com> (Earlier version)
Reviewed by:	kib
Testing by:	tuexen
Sponsored by:	DARPA, AFRL
Sponsored by:	The FreeBSD Foundation (Mitchell Horne)
Differential Revision:	https://reviews.freebsd.org/D14599
2019-01-12 11:21:28 +00:00
..
etc Add supporting changes for Add limited sandbox capability to "make check" 2017-08-14 19:21:37 +00:00
freebsd_test_suite Fix sys/opencrypto/blake2_test when kern.cryptodevallowsoft=0 2018-08-16 23:49:56 +00:00
sys Add support for the Clang Coverage Sanitizer in the kernel (KCOV). 2019-01-12 11:21:28 +00:00
Kyuafile
Makefile Use MK_CHECK_USE_SANDBOX in tests/..., to deal with the fact that 2017-08-02 22:24:08 +00:00
Makefile.depend DIRDEPS_BUILD: Connect MK_TESTS. 2016-03-09 22:46:01 +00:00
Makefile.inc0 Use bsd.opts.mk, not src.opts.mk 2017-08-03 00:35:35 +00:00
README Copy README into /usr/tests 2015-11-20 03:24:04 +00:00

src/tests: The FreeBSD test suite
=================================

To run the FreeBSD test suite:
(1)  Make sure that kyua is installed:
       pkg install kyua
(2)  To run the tests:
       kyua test -k /usr/tests/Kyuafile
(3)  To see the test results:
       kyua report  

For further information on using the test suite, read tests(7):
       man tests

Description of FreeBSD test suite
=================================
The build of the test suite is organized in the following manner:

* The build of all test artifacts is protected by the MK_TESTS knob.
  The user can disable these with the WITHOUT_TESTS setting in
  src.conf(5).

* The goal for /usr/tests/ (the installed test programs) is to follow
  the same hierarchy as /usr/src/ wherever possible, which in turn drives
  several of the design decisions described below.  This simplifies the
  discoverability of tests.  We want a mapping such as:

    /usr/src/bin/cp/      -> /usr/tests/bin/cp/
    /usr/src/lib/libc/    -> /usr/tests/lib/libc/
    /usr/src/usr.bin/cut/ -> /usr/tests/usr.bin/cut/
    ... and many more ...

* Test programs for specific utilities and libraries are located next
  to the source code of such programs.  For example, the tests for the
  src/lib/libcrypt/ library live in src/lib/libcrypt/tests/.  The tests/
  subdirectory is optional and should, in general, be avoided.

* The src/tests/ hierarchy (this directory) provides generic test
  infrastructure and glue code to join all test programs together into
  a single test suite definition.

* The src/tests/ hierarchy also includes cross-functional test programs:
  i.e. test programs that cover more than a single utility or library
  and thus don't fit anywhere else in the tree.  Consider this to follow
  the same rationale as src/share/man/: this directory contains generic
  manual pages while the manual pages that are specific to individual
  tools or libraries live next to the source code.

In order to keep the src/tests/ hierarchy decoupled from the actual test
programs being installed --which is a worthy goal because it simplifies
the addition of new test programs and simplifies the maintenance of the
tree-- the top-level Kyuafile does not know which subdirectories may
exist upfront.  Instead, such Kyuafile automatically detects, at
run-time, which */Kyuafile files exist and uses those directly.

Similarly, every directory in src/ that wants to install a Kyuafile to
just recurse into other subdirectories reuses this Kyuafile with
auto-discovery features.  As an example, take a look at src/lib/tests/
whose sole purpose is to install a Kyuafile into /usr/tests/lib/.
The goal in this specific case is for /usr/tests/lib/ to be generated
entirely from src/lib/.

-- 
$FreeBSD$