9 files changed, 32 insertions, 0 deletions
diff --git a/llvm/lib/Fuzzer/FuzzerDriver.cpp b/llvm/lib/Fuzzer/FuzzerDriver.cpp
index e6c9764f113..2bbcb25275e 100644
--- a/llvm/lib/Fuzzer/FuzzerDriver.cpp
+++ b/llvm/lib/Fuzzer/FuzzerDriver.cpp
@@ -468,6 +468,7 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
   Options.HandleInt = Flags.handle_int;
   Options.HandleSegv = Flags.handle_segv;
   Options.HandleTerm = Flags.handle_term;
+  Options.HandleXfsz = Flags.handle_xfsz;
   SetSignalHandler(Options);
 
   if (Flags.minimize_crash_internal_step)
diff --git a/llvm/lib/Fuzzer/FuzzerFlags.def b/llvm/lib/Fuzzer/FuzzerFlags.def
index 08eaad9856b..22aad353ace 100644
--- a/llvm/lib/Fuzzer/FuzzerFlags.def
+++ b/llvm/lib/Fuzzer/FuzzerFlags.def
@@ -91,6 +91,7 @@ FUZZER_FLAG_INT(handle_ill, 1, "If 1, try to intercept SIGILL.")
 FUZZER_FLAG_INT(handle_fpe, 1, "If 1, try to intercept SIGFPE.")
 FUZZER_FLAG_INT(handle_int, 1, "If 1, try to intercept SIGINT.")
 FUZZER_FLAG_INT(handle_term, 1, "If 1, try to intercept SIGTERM.")
+FUZZER_FLAG_INT(handle_xfsz, 1, "If 1, try to intercept SIGXFSZ.")
 FUZZER_FLAG_INT(close_fd_mask, 0, "If 1, close stdout at startup; "
     "if 2, close stderr; if 3, close both. "
     "Be careful, this will also close e.g. asan's stderr/stdout.")
diff --git a/llvm/lib/Fuzzer/FuzzerInternal.h b/llvm/lib/Fuzzer/FuzzerInternal.h
index c041706092d..0d2c7a78aca 100644
--- a/llvm/lib/Fuzzer/FuzzerInternal.h
+++ b/llvm/lib/Fuzzer/FuzzerInternal.h
@@ -82,6 +82,7 @@ public:
   static void StaticAlarmCallback();
   static void StaticCrashSignalCallback();
   static void StaticInterruptCallback();
+  static void StaticFileSizeExceedCallback();
 
   void ExecuteCallback(const uint8_t *Data, size_t Size);
   size_t RunOne(const uint8_t *Data, size_t Size);
diff --git a/llvm/lib/Fuzzer/FuzzerLoop.cpp b/llvm/lib/Fuzzer/FuzzerLoop.cpp
index 1336f5e4aee..9f49d155799 100644
--- a/llvm/lib/Fuzzer/FuzzerLoop.cpp
+++ b/llvm/lib/Fuzzer/FuzzerLoop.cpp
@@ -266,6 +266,11 @@ void Fuzzer::StaticInterruptCallback() {
   F->InterruptCallback();
 }
 
+void Fuzzer::StaticFileSizeExceedCallback() {
+  Printf("==%lu== ERROR: libFuzzer: file size exceeded\n", GetPid());
+  exit(1);
+}
+
 void Fuzzer::CrashCallback() {
   Printf("==%lu== ERROR: libFuzzer: deadly signal\n", GetPid());
   if (EF->__sanitizer_print_stack_trace)
diff --git a/llvm/lib/Fuzzer/FuzzerMerge.cpp b/llvm/lib/Fuzzer/FuzzerMerge.cpp
index b3d46435fcd..9e559115680 100644
--- a/llvm/lib/Fuzzer/FuzzerMerge.cpp
+++ b/llvm/lib/Fuzzer/FuzzerMerge.cpp
@@ -229,6 +229,11 @@ void Fuzzer::CrashResistantMerge(const std::vector<std::string> &Args,
   ControlFile << NumFilesInFirstCorpus << "\n";
   for (auto &Path: AllFiles)
     ControlFile << Path << "\n";
+  if (!ControlFile) {
+    Printf("MERGE-OUTER: failed to write to the control file: %s\n",
+           CFPath.c_str());
+    exit(1);
+  }
   ControlFile.close();
 
   // Execute the inner process untill it passes.
@@ -246,6 +251,9 @@ void Fuzzer::CrashResistantMerge(const std::vector<std::string> &Args,
   // Read the control file and do the merge.
   Merger M;
   std::ifstream IF(CFPath);
+  IF.seekg(0, IF.end);
+  Printf("MERGE-OUTER: the control file has %zd bytes\n", (size_t)IF.tellg());
+  IF.seekg(0, IF.beg);
   M.ParseOrExit(IF, true);
   IF.close();
   std::vector<std::string> NewFiles;
diff --git a/llvm/lib/Fuzzer/FuzzerOptions.h b/llvm/lib/Fuzzer/FuzzerOptions.h
index cb702d28520..6f72205600b 100644
--- a/llvm/lib/Fuzzer/FuzzerOptions.h
+++ b/llvm/lib/Fuzzer/FuzzerOptions.h
@@ -62,6 +62,7 @@ struct FuzzingOptions {
   bool HandleInt = false;
   bool HandleSegv = false;
   bool HandleTerm = false;
+  bool HandleXfsz = false;
 };
 
 }  // namespace fuzzer
diff --git a/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp b/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp
index 8b484b8effa..e8d48dc81a3 100644
--- a/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp
+++ b/llvm/lib/Fuzzer/FuzzerUtilPosix.cpp
@@ -41,6 +41,10 @@ static void InterruptHandler(int, siginfo_t *, void *) {
   Fuzzer::StaticInterruptCallback();
 }
 
+static void FileSizeExceedHandler(int, siginfo_t *, void *) {
+  Fuzzer::StaticFileSizeExceedCallback();
+}
+
 static void SetSigaction(int signum,
                          void (*callback)(int, siginfo_t *, void *)) {
   struct sigaction sigact;
@@ -80,6 +84,8 @@ void SetSignalHandler(const FuzzingOptions& Options) {
     SetSigaction(SIGILL, CrashHandler);
   if (Options.HandleFpe)
     SetSigaction(SIGFPE, CrashHandler);
+  if (Options.HandleXfsz)
+    SetSigaction(SIGXFSZ, FileSizeExceedHandler);
 }
 
 void SleepSeconds(int Seconds) {
diff --git a/llvm/lib/Fuzzer/FuzzerUtilWindows.cpp b/llvm/lib/Fuzzer/FuzzerUtilWindows.cpp
index 64adb7cd138..3ca1f2c8f56 100644
--- a/llvm/lib/Fuzzer/FuzzerUtilWindows.cpp
+++ b/llvm/lib/Fuzzer/FuzzerUtilWindows.cpp
@@ -58,6 +58,7 @@ LONG CALLBACK ExceptionHandler(PEXCEPTION_POINTERS ExceptionInfo) {
       if (HandlerOpt->HandleFpe)
         Fuzzer::StaticCrashSignalCallback();
       break;
+    // TODO: handle (Options.HandleXfsz)
   }
   return EXCEPTION_CONTINUE_SEARCH;
 }
diff --git a/llvm/lib/Fuzzer/test/merge.test b/llvm/lib/Fuzzer/test/merge.test
index 1f1810eb019..5c7d30e41ca 100644
--- a/llvm/lib/Fuzzer/test/merge.test
+++ b/llvm/lib/Fuzzer/test/merge.test
@@ -44,3 +44,11 @@ MERGE_WITH_CRASH: MERGE-OUTER: 3 new files
 # Check that we actually limit the size with max_len
 RUN: LLVMFuzzer-FullCoverageSetTest -merge=1 %tmp/T1 %tmp/T2  -max_len=5 2>&1 | FileCheck %s --check-prefix=MERGE_LEN5
 MERGE_LEN5: MERGE-OUTER: succesfull in 1 attempt(s)
+
+# Check that we honor TMPDIR
+RUN: TMPDIR=DIR_DOES_NOT_EXIST not LLVMFuzzer-FullCoverageSetTest -merge=1 %tmp/T1 %tmp/T2 2>&1 | FileCheck %s --check-prefix=TMPDIR
+TMPDIR: MERGE-OUTER: failed to write to the control file: DIR_DOES_NOT_EXIST/libFuzzerTemp
+
+# Check that we can report an error if file size exceeded
+RUN: (ulimit -f 1; not LLVMFuzzer-FullCoverageSetTest -merge=1 %tmp/T1 %tmp/T2 2>&1 | FileCheck %s --check-prefix=SIGXFSZ)
+SIGXFSZ: ERROR: libFuzzer: file size exceeded