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 std::string &Data, const std::string &Path) {
68   WriteToFile(reinterpret_cast<const uint8_t *>(Data.c_str()), Data.size(),
69               Path);
70 }
71 
72 void WriteToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
73   // Use raw C interface because this function may be called from a sig handler.
74   FILE *Out = fopen(Path.c_str(), "wb");
75   if (!Out) return;
76   fwrite(Data, sizeof(Data[0]), Size, Out);
77   fclose(Out);
78 }
79 
80 void AppendToFile(const std::string &Data, const std::string &Path) {
81   AppendToFile(reinterpret_cast<const uint8_t *>(Data.data()), Data.size(),
82                Path);
83 }
84 
85 void AppendToFile(const uint8_t *Data, size_t Size, const std::string &Path) {
86   FILE *Out = fopen(Path.c_str(), "a");
87   if (!Out)
88     return;
89   fwrite(Data, sizeof(Data[0]), Size, Out);
90   fclose(Out);
91 }
92 
93 void ReadDirToVectorOfUnits(const char *Path, Vector<Unit> *V, long *Epoch,
94                             size_t MaxSize, bool ExitOnError,
95                             Vector<std::string> *VPaths) {
96   long E = Epoch ? *Epoch : 0;
97   Vector<std::string> Files;
98   ListFilesInDirRecursive(Path, Epoch, &Files, /*TopDir*/true);
99   size_t NumLoaded = 0;
100   for (size_t i = 0; i < Files.size(); i++) {
101     auto &X = Files[i];
102     if (Epoch && GetEpoch(X) < E) continue;
103     NumLoaded++;
104     if ((NumLoaded & (NumLoaded - 1)) == 0 && NumLoaded >= 1024)
105       Printf("Loaded %zd/%zd files from %s\n", NumLoaded, Files.size(), Path);
106     auto S = FileToVector(X, MaxSize, ExitOnError);
107     if (!S.empty()) {
108       V->push_back(S);
109       if (VPaths)
110         VPaths->push_back(X);
111     }
112   }
113 }
114 
115 void GetSizedFilesFromDir(const std::string &Dir, Vector<SizedFile> *V) {
116   Vector<std::string> Files;
117   ListFilesInDirRecursive(Dir, 0, &Files, /*TopDir*/true);
118   for (auto &File : Files)
119     if (size_t Size = FileSize(File))
120       V->push_back({File, Size});
121 }
122 
123 std::string DirPlusFile(const std::string &DirPath,
124                         const std::string &FileName) {
125   return DirPath + GetSeparator() + FileName;
126 }
127 
128 void DupAndCloseStderr() {
129   int OutputFd = DuplicateFile(2);
130   if (OutputFd >= 0) {
131     FILE *NewOutputFile = OpenFile(OutputFd, "w");
132     if (NewOutputFile) {
133       OutputFile = NewOutputFile;
134       if (EF->__sanitizer_set_report_fd)
135         EF->__sanitizer_set_report_fd(
136             reinterpret_cast<void *>(GetHandleFromFd(OutputFd)));
137       DiscardOutput(2);
138     }
139   }
140 }
141 
142 void CloseStdout() {
143   DiscardOutput(1);
144 }
145 
146 void Printf(const char *Fmt, ...) {
147   va_list ap;
148   va_start(ap, Fmt);
149   vfprintf(OutputFile, Fmt, ap);
150   va_end(ap);
151   fflush(OutputFile);
152 }
153 
154 void VPrintf(bool Verbose, const char *Fmt, ...) {
155   if (!Verbose) return;
156   va_list ap;
157   va_start(ap, Fmt);
158   vfprintf(OutputFile, Fmt, ap);
159   va_end(ap);
160   fflush(OutputFile);
161 }
162 
163 static bool MkDirRecursiveInner(const std::string &Leaf) {
164   // Prevent chance of potential infinite recursion
165   if (Leaf == ".")
166     return true;
167 
168   const std::string &Dir = DirName(Leaf);
169 
170   if (IsDirectory(Dir)) {
171     MkDir(Leaf);
172     return IsDirectory(Leaf);
173   }
174 
175   bool ret = MkDirRecursiveInner(Dir);
176   if (!ret) {
177     // Give up early if a previous MkDir failed
178     return ret;
179   }
180 
181   MkDir(Leaf);
182   return IsDirectory(Leaf);
183 }
184 
185 bool MkDirRecursive(const std::string &Dir) {
186   if (Dir.empty())
187     return false;
188 
189   if (IsDirectory(Dir))
190     return true;
191 
192   return MkDirRecursiveInner(Dir);
193 }
194 
195 void RmDirRecursive(const std::string &Dir) {
196   IterateDirRecursive(
197       Dir, [](const std::string &Path) {},
198       [](const std::string &Path) { RmDir(Path); },
199       [](const std::string &Path) { RemoveFile(Path); });
200 }
201 
202 std::string TempPath(const char *Prefix, const char *Extension) {
203   return DirPlusFile(TmpDir(), std::string("libFuzzerTemp.") + Prefix +
204                                    std::to_string(GetPid()) + Extension);
205 }
206 
207 }  // namespace fuzzer
208