[libFuzzer] Don't replace custom signal handlers.
Summary:
This allows to keep handlers installed by sanitizers.
In other cases third-party code can replace handlers after libFuzzer
initialization anyway.
Reviewers: kcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33522
llvm-svn: 303828
diff --git a/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp b/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp
index 0161309..bc85264 100644
--- a/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp
+++ b/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp
@@ -47,8 +47,21 @@
static void SetSigaction(int signum,
void (*callback)(int, siginfo_t *, void *)) {
- struct sigaction sigact;
- memset(&sigact, 0, sizeof(sigact));
+ struct sigaction sigact = {};
+ if (sigaction(signum, nullptr, &sigact)) {
+ Printf("libFuzzer: sigaction failed with %d\n", errno);
+ exit(1);
+ }
+ if (sigact.sa_flags & SA_SIGINFO) {
+ if (sigact.sa_sigaction)
+ return;
+ } else {
+ if (sigact.sa_handler != SIG_DFL && sigact.sa_handler != SIG_IGN &&
+ sigact.sa_handler != SIG_ERR)
+ return;
+ }
+
+ sigact = {};
sigact.sa_sigaction = callback;
if (sigaction(signum, &sigact, 0)) {
Printf("libFuzzer: sigaction failed with %d\n", errno);