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 "Support/FileUtilities.h"
16 #include "Config/unistd.h"
17 #include "Config/fcntl.h"
18 #include "Config/sys/stat.h"
19 #include "Config/sys/types.h"
20 #include "Config/sys/mman.h"
27 /// CheckMagic - Returns true IFF the file named FN begins with Magic. FN must
28 /// name a readable file.
30 bool llvm::CheckMagic(const std::string &FN, const std::string &Magic) {
31 char buf[1 + Magic.size ()];
32 std::ifstream f (FN.c_str ());
33 f.read (buf, Magic.size ());
34 buf[Magic.size ()] = '\0';
38 /// IsArchive - Returns true IFF the file named FN appears to be a "ar" library
39 /// archive. The file named FN must exist.
41 bool llvm::IsArchive(const std::string &FN) {
42 // Inspect the beginning of the file to see if it contains the "ar"
43 // library archive format magic string.
44 return CheckMagic (FN, "!<arch>\012");
47 /// IsBytecode - Returns true IFF the file named FN appears to be an LLVM
48 /// bytecode file. The file named FN must exist.
50 bool llvm::IsBytecode(const std::string &FN) {
51 // Inspect the beginning of the file to see if it contains the LLVM
52 // bytecode format magic string.
53 return CheckMagic (FN, "llvm");
56 /// IsSharedObject - Returns trus IFF the file named FN appears to be a shared
57 /// object with an ELF header. The file named FN must exist.
59 bool llvm::IsSharedObject(const std::string &FN) {
60 // Inspect the beginning of the file to see if it contains the ELF shared
61 // object magic string.
62 static const char elfMagic[] = { 0x7f, 'E', 'L', 'F', '\0' };
63 return CheckMagic(FN, elfMagic);
66 /// FileOpenable - Returns true IFF Filename names an existing regular
67 /// file which we can successfully open.
69 bool llvm::FileOpenable(const std::string &Filename) {
71 if (stat (Filename.c_str (), &s) == -1)
72 return false; // Cannot stat file
73 if (!S_ISREG (s.st_mode))
74 return false; // File is not a regular file
75 std::ifstream FileStream (Filename.c_str ());
77 return false; // File is not openable
81 /// DiffFiles - Compare the two files specified, returning true if they are
82 /// different or if there is a file error. If you specify a string to fill in
83 /// for the error option, it will set the string to an error message if an error
84 /// occurs, allowing the caller to distinguish between a failed diff and a file
87 bool llvm::DiffFiles(const std::string &FileA, const std::string &FileB,
89 std::ifstream FileAStream(FileA.c_str());
91 if (Error) *Error = "Couldn't open file '" + FileA + "'";
95 std::ifstream FileBStream(FileB.c_str());
97 if (Error) *Error = "Couldn't open file '" + FileB + "'";
101 // Compare the two files...
104 C1 = FileAStream.get();
105 C2 = FileBStream.get();
106 if (C1 != C2) return true;
113 /// CopyFile - Copy the specified source file to the specified destination,
114 /// overwriting destination if it exists. This returns true on failure.
116 bool llvm::CopyFile(const std::string &Dest, const std::string &Src) {
117 FDHandle InFD(open(Src.c_str(), O_RDONLY));
118 if (InFD == -1) return true;
120 FileRemover FR(Dest);
122 FDHandle OutFD(open(Dest.c_str(), O_WRONLY|O_CREAT, 0666));
123 if (OutFD == -1) return true;
125 char Buffer[16*1024];
126 while (ssize_t Amt = read(InFD, Buffer, 16*1024)) {
128 if (errno != EINTR) return true; // Error reading the file.
130 char *BufPtr = Buffer;
132 ssize_t AmtWritten = write(OutFD, BufPtr, Amt);
133 if (AmtWritten == -1) {
134 if (errno != EINTR) return true; // Error writing the file.
137 BufPtr += AmtWritten;
143 FR.releaseFile(); // Success!
148 /// MoveFileOverIfUpdated - If the file specified by New is different than Old,
149 /// or if Old does not exist, move the New file over the Old file. Otherwise,
150 /// remove the New file.
152 void llvm::MoveFileOverIfUpdated(const std::string &New,
153 const std::string &Old) {
154 if (DiffFiles(New, Old)) {
155 if (std::rename(New.c_str(), Old.c_str()))
156 std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
158 std::remove(New.c_str());
162 /// removeFile - Delete the specified file
164 void llvm::removeFile(const std::string &Filename) {
165 std::remove(Filename.c_str());
168 /// getUniqueFilename - Return a filename with the specified prefix. If the
169 /// file does not exist yet, return it, otherwise add a suffix to make it
172 std::string llvm::getUniqueFilename(const std::string &FilenameBase) {
173 if (!std::ifstream(FilenameBase.c_str()))
174 return FilenameBase; // Couldn't open the file? Use it!
176 // Create a pattern for mkstemp...
177 char *FNBuffer = new char[FilenameBase.size()+8];
178 strcpy(FNBuffer, FilenameBase.c_str());
179 strcpy(FNBuffer+FilenameBase.size(), "-XXXXXX");
181 // Agree on a temporary file name to use....
183 if ((TempFD = mkstemp(FNBuffer)) == -1) {
184 std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
189 // We don't need to hold the temp file descriptor... we will trust that no one
190 // will overwrite/delete the file while we are working on it...
192 std::string Result(FNBuffer);
197 static bool AddPermissionsBits (const std::string &Filename, mode_t bits) {
198 // Get the umask value from the operating system. We want to use it
199 // when changing the file's permissions. Since calling umask() sets
200 // the umask and returns its old value, we must call it a second
201 // time to reset it to the user's preference.
202 mode_t mask = umask (0777); // The arg. to umask is arbitrary...
205 // Get the file's current mode.
207 if ((stat (Filename.c_str(), &st)) == -1)
210 // Change the file to have whichever permissions bits from 'bits'
211 // that the umask would not disable.
212 if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
218 /// MakeFileExecutable - Make the file named Filename executable by
219 /// setting whichever execute permissions bits the process's current
220 /// umask would allow. Filename must name an existing file or
221 /// directory. Returns true on success, false on error.
223 bool llvm::MakeFileExecutable(const std::string &Filename) {
224 return AddPermissionsBits(Filename, 0111);
227 /// MakeFileReadable - Make the file named Filename readable by
228 /// setting whichever read permissions bits the process's current
229 /// umask would allow. Filename must name an existing file or
230 /// directory. Returns true on success, false on error.
232 bool llvm::MakeFileReadable(const std::string &Filename) {
233 return AddPermissionsBits(Filename, 0444);
236 /// getFileSize - Return the size of the specified file in bytes, or -1 if the
237 /// file cannot be read or does not exist.
238 long long llvm::getFileSize(const std::string &Filename) {
240 if (stat(Filename.c_str(), &StatBuf) == -1)
242 return StatBuf.st_size;
245 /// getFileTimestamp - Get the last modified time for the specified file in an
246 /// unspecified format. This is useful to allow checking to see if a file was
247 /// updated since that last time the timestampt was aquired. If the file does
248 /// not exist or there is an error getting the time-stamp, zero is returned.
249 unsigned long long llvm::getFileTimestamp(const std::string &Filename) {
251 if (stat(Filename.c_str(), &StatBuf) == -1)
253 return StatBuf.st_mtime;
256 /// ReadFileIntoAddressSpace - Attempt to map the specific file into the
257 /// address space of the current process for reading. If this succeeds,
258 /// return the address of the buffer and the length of the file mapped. On
259 /// failure, return null.
260 void *llvm::ReadFileIntoAddressSpace(const std::string &Filename,
262 #ifdef HAVE_MMAP_FILE
263 Length = getFileSize(Filename);
264 if ((int)Length == -1) return 0;
266 FDHandle FD(open(Filename.c_str(), O_RDONLY));
267 if (FD == -1) return 0;
269 // If the file has a length of zero, mmap might return a null pointer. In
270 // this case, allocate a single byte of memory and return it instead.
274 // mmap in the file all at once...
275 void *Buffer = (void*)mmap(0, Length, PROT_READ, MAP_PRIVATE, FD, 0);
277 if (Buffer == (void*)MAP_FAILED)
282 // FIXME: implement with read/write
287 /// UnmapFileFromAddressSpace - Remove the specified file from the current
289 void llvm::UnmapFileFromAddressSpace(void *Buffer, unsigned Length) {
290 #ifdef HAVE_MMAP_FILE
292 munmap((char*)Buffer, Length);
294 free(Buffer); // Zero byte files are malloc(1)'s.
300 //===----------------------------------------------------------------------===//
301 // FDHandle class implementation
304 FDHandle::~FDHandle() throw() {
305 if (FD != -1) close(FD);
308 FDHandle &FDHandle::operator=(int fd) throw() {
309 if (FD != -1) close(FD);