[sanitizer][esan] Add internal_sigaction_syscall

Summary:
Adds a version of sigaction that uses a raw system call, to avoid circular
dependencies and support calling sigaction prior to setting up
interceptors.  The new sigaction relies on an assembly sigreturn routine
for its restorer, which is Linux x86_64-only for now.

Uses the new sigaction to initialize the working set tool's shadow fault
handler prior to libc interceptor being set up.  This is required to
support instrumentation invoked during interceptor setup, which happens
with an instrumented tcmalloc or other allocator compiled with esan.

Adds a test that emulates an instrumented allocator.

Reviewers: aizatsky

Subscribers: vitalybuka, tberghammer, zhaoqin, danalbert, kcc, srhines, eugenis, llvm-commits, kubabrecka

Differential Revision: http://reviews.llvm.org/D21083

llvm-svn: 272676

1 files changed, 4 insertions, 0 deletions

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.h b/compiler-rt/lib/sanitizer_common/sanitizer_linux.h
index beb43568ad0..526fa4426e3 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.h
@@ -42,6 +42,10 @@ uptr internal_prctl(int option, uptr arg2, uptr arg3, uptr arg4, uptr arg5);
 // (like the process-wide error reporting SEGV handler) must use
 // internal_sigaction instead.
 int internal_sigaction_norestorer(int signum, const void *act, void *oldact);
+#if defined(__x86_64__) && !SANITIZER_GO
+// Uses a raw system call to avoid interceptors.
+int internal_sigaction_syscall(int signum, const void *act, void *oldact);
+#endif
 void internal_sigdelset(__sanitizer_sigset_t *set, int signum);
 #if defined(__x86_64__) || defined(__mips__) || defined(__aarch64__) \
   || defined(__powerpc64__) || defined(__s390__)