[libFuzzer] use raw C IO to reduce the risk of a deadlock in a signal handler.

[oota-llvm.git] / lib / Fuzzer / FuzzerIO.cpp

diff --git a/lib/Fuzzer/FuzzerIO.cpp b/lib/Fuzzer/FuzzerIO.cpp
index c6636c8681832fc318877871e089fc77fb5ba936..f0295e9a730875aa545c50fb361bf6879631d554 100644 (file)
--- a/lib/Fuzzer/FuzzerIO.cpp
+++ b/lib/Fuzzer/FuzzerIO.cpp
@@ -9,19 +9,22 @@
 // IO functions.
 //===----------------------------------------------------------------------===//
 #include "FuzzerInternal.h"
-#include <iostream>
 #include <iterator>
 #include <fstream>
 #include <dirent.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <unistd.h>
+#include <cstdio>
 
 namespace fuzzer {
 
 static long GetEpoch(const std::string &Path) {
   struct stat St;
-  if (stat(Path.c_str(), &St)) return 0;
+  if (stat(Path.c_str(), &St)) {
+    Printf("Can not stat: %s; exiting\n", Path.c_str());
+    exit(1);
+  }
   return St.st_mtime;
 }
 
@@ -34,7 +37,10 @@ static std::vector<std::string> ListFilesInDir(const std::string &Dir,
     *Epoch = E;
   }
   DIR *D = opendir(Dir.c_str());
-  if (!D) return V;
+  if (!D) {
+    Printf("No such directory: %s; exiting\n", Dir.c_str());
+    exit(1);
+  }
   while (auto E = readdir(D)) {
     if (E->d_type == DT_REG || E->d_type == DT_LNK)
       V.push_back(E->d_name);
@@ -56,14 +62,15 @@ std::string FileToString(const std::string &Path) {
 }
 
 void CopyFileToErr(const std::string &Path) {
-  std::ifstream T(Path);
-  std::copy(std::istreambuf_iterator<char>(T), std::istreambuf_iterator<char>(),
-            std::ostream_iterator<char>(std::cerr, ""));
+  Printf("%s", FileToString(Path).c_str());
 }
 
 void WriteToFile(const Unit &U, const std::string &Path) {
-  std::ofstream OF(Path);
-  OF.write((const char*)U.data(), U.size());
+  // Use raw C interface because this function may be called from a sig handler.
+  FILE *Out = fopen(Path.c_str(), "w");
+  if (!Out) return;
+  fwrite(U.data(), sizeof(U[0]), U.size(), Out);
+  fclose(Out);
 }
 
 void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
@@ -86,4 +93,11 @@ void PrintFileAsBase64(const std::string &Path) {
   ExecuteCommand(Cmd);
 }
 
+void Printf(const char *Fmt, ...) {
+  va_list ap;
+  va_start(ap, Fmt);
+  vfprintf(stderr, Fmt, ap);
+  va_end(ap);
+}
+
 }  // namespace fuzzer