executor, fuzzer: change the way Syzkaller opens the KCOV device

We have implemented a new version of KCOV, which is able to dump
comparison operands' data, obtained from Clang's instrumentation hooks
__sanitizer_cov_trace_cmp[1248], __sanitizer_cov_trace_const_cmp[1248]
and __sanitizer_cov_trace_switch.

Current KCOV implementation can work in two modes: "Dump only the PCs"
or "Dump only comparisons' data". Mode selection is done by the
following series of calls:

fd = open(KCOV_PATH, ...); // works as previous
ioctl(fd, KCOV_INIT_TRACE, ...); // works as previous
mmap(fd, ...); // works as previous
ioctl(fd, KCOV_ENABLE, mode);
// mode = KCOV_MODE_TRACE_CMP or mode = KCOV_MODE_TRACE_PC

Note that this new interface is backwards compatible, as old KCOV
devices will just return -EINVAL for the last ioctl. This way we can
distinguish if the KCOV device is able to dump the comparisons.

Main changes in this commit:
    1. Fuzzer now checks at startup which type (new/old) of KCOV device
is running.
    2. Executor now receives an additional flag, which indicates if
executor should read the comparisons data from KCOV. The flag works on
per-call basis, so executor can collect PCs or Comps for each
individual syscall.

0 files changed, 0 insertions, 0 deletions