1 //===- Support/FileUtilities.cpp - File System Utilities ------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements a family of utility functions which are useful for doing
11 // various things with files.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/Support/FileUtilities.h"
16 #include "llvm/Support/DataTypes.h"
17 #include "llvm/System/Path.h"
18 #include "llvm/Config/unistd.h"
19 #include "llvm/Config/fcntl.h"
20 #include "llvm/Config/sys/types.h"
21 #include "llvm/Config/sys/stat.h"
22 #include "llvm/Config/sys/mman.h"
23 #include "llvm/Config/alloca.h"
30 /// DiffFiles - Compare the two files specified, returning true if they are
31 /// different or if there is a file error. If you specify a string to fill in
32 /// for the error option, it will set the string to an error message if an error
33 /// occurs, allowing the caller to distinguish between a failed diff and a file
36 bool llvm::DiffFiles(const std::string &FileA, const std::string &FileB,
38 std::ifstream FileAStream(FileA.c_str());
40 if (Error) *Error = "Couldn't open file '" + FileA + "'";
44 std::ifstream FileBStream(FileB.c_str());
46 if (Error) *Error = "Couldn't open file '" + FileB + "'";
50 // Compare the two files...
53 C1 = FileAStream.get();
54 C2 = FileBStream.get();
55 if (C1 != C2) return true;
62 /// CopyFile - Copy the specified source file to the specified destination,
63 /// overwriting destination if it exists. This returns true on failure.
65 bool llvm::CopyFile(const std::string &Dest, const std::string &Src) {
66 FDHandle InFD(open(Src.c_str(), O_RDONLY));
67 if (InFD == -1) return true;
71 FDHandle OutFD(open(Dest.c_str(), O_WRONLY|O_CREAT, 0666));
72 if (OutFD == -1) return true;
75 while (ssize_t Amt = read(InFD, Buffer, 16*1024)) {
77 if (errno != EINTR) return true; // Error reading the file.
79 char *BufPtr = Buffer;
81 ssize_t AmtWritten = write(OutFD, BufPtr, Amt);
82 if (AmtWritten == -1) {
83 if (errno != EINTR) return true; // Error writing the file.
92 FR.releaseFile(); // Success!
97 /// MoveFileOverIfUpdated - If the file specified by New is different than Old,
98 /// or if Old does not exist, move the New file over the Old file. Otherwise,
99 /// remove the New file.
101 void llvm::MoveFileOverIfUpdated(const std::string &New,
102 const std::string &Old) {
103 if (DiffFiles(New, Old)) {
104 if (std::rename(New.c_str(), Old.c_str()))
105 std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
107 std::remove(New.c_str());
111 /// removeFile - Delete the specified file
113 void llvm::removeFile(const std::string &Filename) {
114 std::remove(Filename.c_str());
117 /// getUniqueFilename - Return a filename with the specified prefix. If the
118 /// file does not exist yet, return it, otherwise add a suffix to make it
121 std::string llvm::getUniqueFilename(const std::string &FilenameBase) {
122 if (!std::ifstream(FilenameBase.c_str()))
123 return FilenameBase; // Couldn't open the file? Use it!
125 // Create a pattern for mkstemp...
126 char *FNBuffer = new char[FilenameBase.size()+8];
127 strcpy(FNBuffer, FilenameBase.c_str());
128 strcpy(FNBuffer+FilenameBase.size(), "-XXXXXX");
130 // Agree on a temporary file name to use....
131 #if defined(HAVE_MKSTEMP) && !defined(_MSC_VER)
133 if ((TempFD = mkstemp(FNBuffer)) == -1) {
134 // FIXME: this should return an emtpy string or something and allow the
135 // caller to deal with the error!
136 std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
141 // We don't need to hold the temp file descriptor... we will trust that no one
142 // will overwrite/delete the file while we are working on it...
145 // If we don't have mkstemp, use the old and obsolete mktemp function.
146 if (mktemp(FNBuffer) == 0) {
147 // FIXME: this should return an emtpy string or something and allow the
148 // caller to deal with the error!
149 std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
155 std::string Result(FNBuffer);
160 static bool AddPermissionsBits (const std::string &Filename, int bits) {
161 // Get the umask value from the operating system. We want to use it
162 // when changing the file's permissions. Since calling umask() sets
163 // the umask and returns its old value, we must call it a second
164 // time to reset it to the user's preference.
165 int mask = umask(0777); // The arg. to umask is arbitrary.
166 umask(mask); // Restore the umask.
168 // Get the file's current mode.
170 if ((stat(Filename.c_str(), &st)) == -1)
173 // Change the file to have whichever permissions bits from 'bits'
174 // that the umask would not disable.
175 if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
181 /// MakeFileExecutable - Make the file named Filename executable by
182 /// setting whichever execute permissions bits the process's current
183 /// umask would allow. Filename must name an existing file or
184 /// directory. Returns true on success, false on error.
186 bool llvm::MakeFileExecutable(const std::string &Filename) {
187 return AddPermissionsBits(Filename, 0111);
190 /// MakeFileReadable - Make the file named Filename readable by
191 /// setting whichever read permissions bits the process's current
192 /// umask would allow. Filename must name an existing file or
193 /// directory. Returns true on success, false on error.
195 bool llvm::MakeFileReadable(const std::string &Filename) {
196 return AddPermissionsBits(Filename, 0444);
199 /// ReadFileIntoAddressSpace - Attempt to map the specific file into the
200 /// address space of the current process for reading. If this succeeds,
201 /// return the address of the buffer and the length of the file mapped. On
202 /// failure, return null.
203 void *llvm::ReadFileIntoAddressSpace(const std::string &Filename,
205 #if defined(HAVE_MMAP_FILE) && !defined(_MSC_VER)
206 sys::Path File(Filename);
207 Length = (unsigned)File.getSize();
208 if ((int)Length == -1) return 0;
210 FDHandle FD(open(Filename.c_str(), O_RDONLY));
211 if (FD == -1) return 0;
213 // If the file has a length of zero, mmap might return a null pointer. In
214 // this case, allocate a single byte of memory and return it instead.
218 // mmap in the file all at once...
219 void *Buffer = (void*)mmap(0, Length, PROT_READ, MAP_PRIVATE, FD, 0);
221 if (Buffer == (void*)MAP_FAILED)
226 // FIXME: implement with read/write
227 #error Unimplemented ReadFileIntoAddressSpace - need to use read/write.
232 /// UnmapFileFromAddressSpace - Remove the specified file from the current
234 void llvm::UnmapFileFromAddressSpace(void *Buffer, unsigned Length) {
235 #if defined(HAVE_MMAP_FILE) && !defined(_MSC_VER)
237 munmap((char*)Buffer, Length);
239 free(Buffer); // Zero byte files are malloc(1)'s.
245 //===----------------------------------------------------------------------===//
246 // FDHandle class implementation
249 FDHandle::~FDHandle() throw() {
250 if (FD != -1) close(FD);
253 FDHandle &FDHandle::operator=(int fd) throw() {
254 if (FD != -1) close(FD);