Fix fuzzers to actually run.

test/core/compression/message_compress_corpus/dummy

@@ -0,0 +1 @@
+x

test/core/compression/message_decompress_corpus/dummy

@@ -0,0 +1 @@
+x

test/core/compression/stream_compression_corpus/dummy

@@ -0,0 +1 @@
+x

test/core/compression/stream_decompression_corpus/dummy

@@ -0,0 +1 @@
+x

test/core/slice/b64_decode_fuzzer.cc

@@ -19,6 +19,8 @@
 #include <stdbool.h>
 #include <stdint.h>
 
+#include <grpc/grpc.h>
+
 #include "src/core/lib/slice/b64.h"
 
 bool squelch = true;
@@ -26,9 +28,11 @@ bool leak_check = true;
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   if (size < 1) return 0;
+  grpc_init();
   const bool url_safe = static_cast<uint8_t>(0x100) < data[0];
   grpc_slice res = grpc_base64_decode_with_len(
       reinterpret_cast<const char*>(data + 1), size - 1, url_safe);
   grpc_slice_unref(res);
+  grpc_shutdown_blocking();
   return 0;
 }

test/core/util/fuzzer_corpus_test.cc

@@ -26,6 +26,8 @@
 #include <stdio.h>
 #include <sys/types.h>
 
+#include <grpc/grpc.h>
+
 #include "src/core/lib/gpr/env.h"
 #include "src/core/lib/iomgr/load_file.h"
 #include "test/core/util/test_config.h"
@@ -48,15 +50,24 @@ DEFINE_string(directory, "", "Use this directory as test data");
 class FuzzerCorpusTest : public ::testing::TestWithParam<std::string> {};
 
 TEST_P(FuzzerCorpusTest, RunOneExample) {
+  // Need to call grpc_init() here to use a slice, but need to shut it
+  // down before calling LLVMFuzzerTestOneInput(), because most
+  // implementations of that function will initialize and shutdown gRPC
+  // internally.
+  grpc_init();
   gpr_log(GPR_DEBUG, "Example file: %s", GetParam().c_str());
   grpc_slice buffer;
   squelch = false;
   leak_check = false;
   GPR_ASSERT(GRPC_LOG_IF_ERROR("load_file",
                                grpc_load_file(GetParam().c_str(), 0, &buffer)));
-  LLVMFuzzerTestOneInput(GRPC_SLICE_START_PTR(buffer),
-                         GRPC_SLICE_LENGTH(buffer));
+  size_t length = GRPC_SLICE_LENGTH(buffer);
+  void* data = gpr_malloc(length);
+  memcpy(data, GPR_SLICE_START_PTR(buffer), length);
   grpc_slice_unref(buffer);
+  grpc_shutdown_blocking();
+  LLVMFuzzerTestOneInput(static_cast<uint8_t*>(data), length);
+  gpr_free(data);
 }
 
 class ExampleGenerator
@@ -72,19 +83,21 @@ class ExampleGenerator
       if (!FLAGS_file.empty()) examples_.push_back(FLAGS_file);
       if (!FLAGS_directory.empty()) {
         char* test_srcdir = gpr_getenv("TEST_SRCDIR");
+        gpr_log(GPR_DEBUG, "test_srcdir=\"%s\"", test_srcdir);
+        std::string directory = FLAGS_directory;
         if (test_srcdir != nullptr) {
-          FLAGS_directory = test_srcdir +
-                            std::string("/com_github_grpc_grpc/") +
-                            FLAGS_directory;
+          directory =
+              test_srcdir + std::string("/com_github_grpc_grpc/") + directory;
         }
+        gpr_log(GPR_DEBUG, "Using corpus directory: %s", directory.c_str());
         DIR* dp;
         struct dirent* ep;
-        dp = opendir(FLAGS_directory.c_str());
+        dp = opendir(directory.c_str());
 
         if (dp != nullptr) {
           while ((ep = readdir(dp)) != nullptr) {
-            if (ep->d_type == DT_REG) {
-              examples_.push_back(FLAGS_directory + "/" + ep->d_name);
+            if (strcmp(ep->d_name, ".") != 0 && strcmp(ep->d_name, "..") != 0) {
+              examples_.push_back(directory + "/" + ep->d_name);
             }
           }
 
@@ -96,6 +109,9 @@ class ExampleGenerator
         gpr_free(test_srcdir);
       }
     }
+    // Make sure we don't succeed without doing anything, which caused
+    // us to be blind to our fuzzers not running for 9 months.
+    GPR_ASSERT(!examples_.empty());
   }
 
   mutable std::vector<std::string> examples_;
@@ -146,8 +162,8 @@ INSTANTIATE_TEST_SUITE_P(
 
 int main(int argc, char** argv) {
   grpc::testing::TestEnvironment env(argc, argv);
-  ::testing::InitGoogleTest(&argc, argv);
   grpc::testing::InitTest(&argc, &argv, true);
+  ::testing::InitGoogleTest(&argc, argv);
 
   return RUN_ALL_TESTS();
 }