[libFuzzer] add a flag close_fd_mask so that we can silence spammy targets by closing stderr/stdout

llvm-svn: 263831

1 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/Fuzzer/test/SpamyTest.cpp b/llvm/lib/Fuzzer/test/SpamyTest.cpp
new file mode 100644
index 00000000000..63776d6dfb9
--- /dev/null
+++ b/llvm/lib/Fuzzer/test/SpamyTest.cpp
@@ -0,0 +1,18 @@
+// The test spams to stderr and stdout.
+#include <assert.h>
+#include <cstdint>
+#include <cstdio>
+#include <cstddef>
+#include <iostream>
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
+  assert(Data);
+  printf("PRINTF_STDOUT\n");
+  fflush(stdout);
+  fprintf(stderr, "PRINTF_STDERR\n");
+  std::cout << "STREAM_COUT\n";
+  std::cout.flush();
+  std::cerr << "STREAM_CERR\n";
+  return 0;
+}
+