1 //===- FuzzerIO.cpp - IO utils. -------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 // IO functions.
9 //===----------------------------------------------------------------------===//
10 
11 #include "FuzzerDefs.h"
12 #include "FuzzerExtFunctions.h"
13 #include "FuzzerIO.h"
14 #include "FuzzerUtil.h"
15 #include <algorithm>
16 #include <cstdarg>
17 #include <fstream>
18 #include <iterator>
19 #include <sys/stat.h>
20 #include <sys/types.h>
21 
22 namespace fuzzer {
23 
24 static FILE *OutputFile = stderr;
25 
26 long GetEpoch(const std::string &Path) {
27   struct stat St;
28   if (stat(Path.c_str(), &St))
29     return 0;  // Can't stat, be conservative.
30   return St.st_mtime;
31 }
32 
33 Unit FileToVector(const std::string &Path, size_t MaxSize, bool ExitOnError) {
34   std::ifstream T(Path, std::ios::binary);
35   if (ExitOnError && !T) {
36     Printf("No such directory: %s; exiting\n", Path.c_str());
37     exit(1);
38   }
39 
40   T.seekg(0, T.end);
41   auto EndPos = T.tellg();
42   if (EndPos < 0) return {};
43   size_t FileLen = EndPos;
44   if (MaxSize)
45     FileLen = std::min(FileLen, MaxSize);
46 
47   T.seekg(0, T.beg);
48   Unit Res(FileLen);
49   T.read(reinterpret_cast<char *>(Res.data()), FileLen);
50   return Res;
51 }
52 
53 std::string FileToString(const std::string &Path) {
54   std::ifstream T(Path, std::ios::binary);
55   return std::string((std::istreambuf_iterator<char>(T)),
56                      std::istreambuf_iterator<char>());
57 }
58 
59 void CopyFileToErr(const std::string &Path) {
60   Printf("%s", FileToString(Path).c_str());
61 }
62 
63 void WriteToFile(const Unit &U, const std::string &Path) {
64   WriteToFile(U.data(), U.size(), Path);
65 }
66 
67 void WriteToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
68   // Use raw C interface because this function may be called from a sig handler.
69   FILE *Out = fopen(Path.c_str(), "wb");
70   if (!Out) return;
71   fwrite(Data, sizeof(Data[0]), Size, Out);
72   fclose(Out);
73 }
74 
75 void ReadDirToVectorOfUnits(const char *Path, Vector<Unit> *V,
76                             long *Epoch, size_t MaxSize, bool ExitOnError) {
77   long E = Epoch ? *Epoch : 0;
78   Vector<std::string> Files;
79   ListFilesInDirRecursive(Path, Epoch, &Files, /*TopDir*/true);
80   size_t NumLoaded = 0;
81   for (size_t i = 0; i < Files.size(); i++) {
82     auto &X = Files[i];
83     if (Epoch && GetEpoch(X) < E) continue;
84     NumLoaded++;
85     if ((NumLoaded & (NumLoaded - 1)) == 0 && NumLoaded >= 1024)
86       Printf("Loaded %zd/%zd files from %s\n", NumLoaded, Files.size(), Path);
87     auto S = FileToVector(X, MaxSize, ExitOnError);
88     if (!S.empty())
89       V->push_back(S);
90   }
91 }
92 
93 
94 void GetSizedFilesFromDir(const std::string &Dir, Vector<SizedFile> *V) {
95   Vector<std::string> Files;
96   ListFilesInDirRecursive(Dir, 0, &Files, /*TopDir*/true);
97   for (auto &File : Files)
98     if (size_t Size = FileSize(File))
99       V->push_back({File, Size});
100 }
101 
102 std::string DirPlusFile(const std::string &DirPath,
103                         const std::string &FileName) {
104   return DirPath + GetSeparator() + FileName;
105 }
106 
107 void DupAndCloseStderr() {
108   int OutputFd = DuplicateFile(2);
109   if (OutputFd > 0) {
110     FILE *NewOutputFile = OpenFile(OutputFd, "w");
111     if (NewOutputFile) {
112       OutputFile = NewOutputFile;
113       if (EF->__sanitizer_set_report_fd)
114         EF->__sanitizer_set_report_fd(
115             reinterpret_cast<void *>(GetHandleFromFd(OutputFd)));
116       DiscardOutput(2);
117     }
118   }
119 }
120 
121 void CloseStdout() {
122   DiscardOutput(1);
123 }
124 
125 void Printf(const char *Fmt, ...) {
126   va_list ap;
127   va_start(ap, Fmt);
128   vfprintf(OutputFile, Fmt, ap);
129   va_end(ap);
130   fflush(OutputFile);
131 }
132 
133 void VPrintf(bool Verbose, const char *Fmt, ...) {
134   if (!Verbose) return;
135   va_list ap;
136   va_start(ap, Fmt);
137   vfprintf(OutputFile, Fmt, ap);
138   va_end(ap);
139   fflush(OutputFile);
140 }
141 
142 void RmDirRecursive(const std::string &Dir) {
143   IterateDirRecursive(
144       Dir, [](const std::string &Path) {},
145       [](const std::string &Path) { RmDir(Path); },
146       [](const std::string &Path) { RemoveFile(Path); });
147 }
148 
149 std::string TempPath(const char *Extension) {
150   return DirPlusFile(TmpDir(),
151                      "libFuzzerTemp." + std::to_string(GetPid()) + Extension);
152 }
153 
154 }  // namespace fuzzer
155