[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 81f37aa3c0137b2e73959f22d4b555b16384e785..f0295e9a730875aa545c50fb361bf6879631d554 100644 (file)
--- a/lib/Fuzzer/FuzzerIO.cpp
+++ b/lib/Fuzzer/FuzzerIO.cpp
@@ -9,16 +9,38 @@
 // 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 std::vector<std::string> ListFilesInDir(const std::string &Dir) {
+static long GetEpoch(const std::string &Path) {
+  struct stat St;
+  if (stat(Path.c_str(), &St)) {
+    Printf("Can not stat: %s; exiting\n", Path.c_str());
+    exit(1);
+  }
+  return St.st_mtime;
+}
+
+static std::vector<std::string> ListFilesInDir(const std::string &Dir,
+                                               long *Epoch) {
   std::vector<std::string> V;
+  if (Epoch) {
+    auto E = GetEpoch(Dir.c_str());
+    if (*Epoch >= E) return V;
+    *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);
@@ -40,19 +62,25 @@ 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) {
-  for (auto &X : ListFilesInDir(Path))
-    V->push_back(FileToVector(DirPlusFile(Path, X)));
+void ReadDirToVectorOfUnits(const char *Path, std::vector<Unit> *V,
+                            long *Epoch) {
+  long E = Epoch ? *Epoch : 0;
+  for (auto &X : ListFilesInDir(Path, Epoch)) {
+    auto FilePath = DirPlusFile(Path, X);
+    if (Epoch && GetEpoch(FilePath) < E) continue;
+    V->push_back(FileToVector(FilePath));
+  }
 }
 
 std::string DirPlusFile(const std::string &DirPath,
@@ -62,7 +90,14 @@ std::string DirPlusFile(const std::string &DirPath,
 
 void PrintFileAsBase64(const std::string &Path) {
   std::string Cmd = "base64 -w 0 < " + Path + "; echo";
-  system(Cmd.c_str());
+  ExecuteCommand(Cmd);
+}
+
+void Printf(const char *Fmt, ...) {
+  va_list ap;
+  va_start(ap, Fmt);
+  vfprintf(stderr, Fmt, ap);
+  va_end(ap);
 }
 
 }  // namespace fuzzer