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/Config/unistd.h"
18 #include "llvm/Config/fcntl.h"
19 #include "llvm/Config/sys/types.h"
20 #include "llvm/Config/sys/stat.h"
21 #include "llvm/Config/sys/mman.h"
22 #include "llvm/Config/alloca.h"
29 /// CheckMagic - Returns true IFF the file named FN begins with Magic. FN must
30 /// name a readable file.
32 bool llvm::CheckMagic(const std::string &FN, const std::string &Magic) {
33 char *buf = (char*)alloca(1 + Magic.size());
34 std::ifstream f(FN.c_str());
35 f.read(buf, Magic.size());
36 buf[Magic.size()] = '\0';
40 /// IsArchive - Returns true IFF the file named FN appears to be a "ar" library
41 /// archive. The file named FN must exist.
43 bool llvm::IsArchive(const std::string &FN) {
44 // Inspect the beginning of the file to see if it contains the "ar"
45 // library archive format magic string.
46 return CheckMagic(FN, "!<arch>\012");
49 /// IsBytecode - Returns true IFF the file named FN appears to be an LLVM
50 /// bytecode file. The file named FN must exist.
52 bool llvm::IsBytecode(const std::string &FN) {
53 // Inspect the beginning of the file to see if it contains the LLVM
54 // bytecode format magic string.
55 return CheckMagic (FN, "llvm");
58 /// IsSharedObject - Returns trus IFF the file named FN appears to be a shared
59 /// object with an ELF header. The file named FN must exist.
61 bool llvm::IsSharedObject(const std::string &FN) {
62 // Inspect the beginning of the file to see if it contains the ELF shared
63 // object magic string.
64 static const char elfMagic[] = { 0x7f, 'E', 'L', 'F', '\0' };
65 return CheckMagic(FN, elfMagic);
68 /// FileOpenable - Returns true IFF Filename names an existing regular
69 /// file which we can successfully open.
71 bool llvm::FileOpenable(const std::string &Filename) {
73 if (stat (Filename.c_str (), &s) == -1)
74 return false; // Cannot stat file
75 if (!S_ISREG (s.st_mode))
76 return false; // File is not a regular file
77 std::ifstream FileStream (Filename.c_str ());
79 return false; // File is not openable
83 /// DiffFiles - Compare the two files specified, returning true if they are
84 /// different or if there is a file error. If you specify a string to fill in
85 /// for the error option, it will set the string to an error message if an error
86 /// occurs, allowing the caller to distinguish between a failed diff and a file
89 bool llvm::DiffFiles(const std::string &FileA, const std::string &FileB,
91 std::ifstream FileAStream(FileA.c_str());
93 if (Error) *Error = "Couldn't open file '" + FileA + "'";
97 std::ifstream FileBStream(FileB.c_str());
99 if (Error) *Error = "Couldn't open file '" + FileB + "'";
103 // Compare the two files...
106 C1 = FileAStream.get();
107 C2 = FileBStream.get();
108 if (C1 != C2) return true;
115 /// CopyFile - Copy the specified source file to the specified destination,
116 /// overwriting destination if it exists. This returns true on failure.
118 bool llvm::CopyFile(const std::string &Dest, const std::string &Src) {
119 FDHandle InFD(open(Src.c_str(), O_RDONLY));
120 if (InFD == -1) return true;
122 FileRemover FR(Dest);
124 FDHandle OutFD(open(Dest.c_str(), O_WRONLY|O_CREAT, 0666));
125 if (OutFD == -1) return true;
127 char Buffer[16*1024];
128 while (ssize_t Amt = read(InFD, Buffer, 16*1024)) {
130 if (errno != EINTR) return true; // Error reading the file.
132 char *BufPtr = Buffer;
134 ssize_t AmtWritten = write(OutFD, BufPtr, Amt);
135 if (AmtWritten == -1) {
136 if (errno != EINTR) return true; // Error writing the file.
139 BufPtr += AmtWritten;
145 FR.releaseFile(); // Success!
150 /// MoveFileOverIfUpdated - If the file specified by New is different than Old,
151 /// or if Old does not exist, move the New file over the Old file. Otherwise,
152 /// remove the New file.
154 void llvm::MoveFileOverIfUpdated(const std::string &New,
155 const std::string &Old) {
156 if (DiffFiles(New, Old)) {
157 if (std::rename(New.c_str(), Old.c_str()))
158 std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
160 std::remove(New.c_str());
164 /// removeFile - Delete the specified file
166 void llvm::removeFile(const std::string &Filename) {
167 std::remove(Filename.c_str());
170 /// getUniqueFilename - Return a filename with the specified prefix. If the
171 /// file does not exist yet, return it, otherwise add a suffix to make it
174 std::string llvm::getUniqueFilename(const std::string &FilenameBase) {
175 if (!std::ifstream(FilenameBase.c_str()))
176 return FilenameBase; // Couldn't open the file? Use it!
178 // Create a pattern for mkstemp...
179 char *FNBuffer = new char[FilenameBase.size()+8];
180 strcpy(FNBuffer, FilenameBase.c_str());
181 strcpy(FNBuffer+FilenameBase.size(), "-XXXXXX");
183 // Agree on a temporary file name to use....
184 #if defined(HAVE_MKSTEMP) && !defined(_MSC_VER)
186 if ((TempFD = mkstemp(FNBuffer)) == -1) {
187 // FIXME: this should return an emtpy string or something and allow the
188 // caller to deal with the error!
189 std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
194 // We don't need to hold the temp file descriptor... we will trust that no one
195 // will overwrite/delete the file while we are working on it...
198 // If we don't have mkstemp, use the old and obsolete mktemp function.
199 if (mktemp(FNBuffer) == 0) {
200 // FIXME: this should return an emtpy string or something and allow the
201 // caller to deal with the error!
202 std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
208 std::string Result(FNBuffer);
213 static bool AddPermissionsBits (const std::string &Filename, int bits) {
214 // Get the umask value from the operating system. We want to use it
215 // when changing the file's permissions. Since calling umask() sets
216 // the umask and returns its old value, we must call it a second
217 // time to reset it to the user's preference.
218 int mask = umask(0777); // The arg. to umask is arbitrary.
219 umask(mask); // Restore the umask.
221 // Get the file's current mode.
223 if ((stat(Filename.c_str(), &st)) == -1)
226 // Change the file to have whichever permissions bits from 'bits'
227 // that the umask would not disable.
228 if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
234 /// MakeFileExecutable - Make the file named Filename executable by
235 /// setting whichever execute permissions bits the process's current
236 /// umask would allow. Filename must name an existing file or
237 /// directory. Returns true on success, false on error.
239 bool llvm::MakeFileExecutable(const std::string &Filename) {
240 return AddPermissionsBits(Filename, 0111);
243 /// MakeFileReadable - Make the file named Filename readable by
244 /// setting whichever read permissions bits the process's current
245 /// umask would allow. Filename must name an existing file or
246 /// directory. Returns true on success, false on error.
248 bool llvm::MakeFileReadable(const std::string &Filename) {
249 return AddPermissionsBits(Filename, 0444);
252 /// getFileSize - Return the size of the specified file in bytes, or -1 if the
253 /// file cannot be read or does not exist.
254 long long llvm::getFileSize(const std::string &Filename) {
256 if (stat(Filename.c_str(), &StatBuf) == -1)
258 return StatBuf.st_size;
261 /// getFileTimestamp - Get the last modified time for the specified file in an
262 /// unspecified format. This is useful to allow checking to see if a file was
263 /// updated since that last time the timestampt was aquired. If the file does
264 /// not exist or there is an error getting the time-stamp, zero is returned.
265 unsigned long long llvm::getFileTimestamp(const std::string &Filename) {
267 if (stat(Filename.c_str(), &StatBuf) == -1)
269 return StatBuf.st_mtime;
272 /// ReadFileIntoAddressSpace - Attempt to map the specific file into the
273 /// address space of the current process for reading. If this succeeds,
274 /// return the address of the buffer and the length of the file mapped. On
275 /// failure, return null.
276 void *llvm::ReadFileIntoAddressSpace(const std::string &Filename,
278 #if defined(HAVE_MMAP_FILE) && !defined(_MSC_VER)
279 Length = (unsigned)getFileSize(Filename);
280 if ((int)Length == -1) return 0;
282 FDHandle FD(open(Filename.c_str(), O_RDONLY));
283 if (FD == -1) return 0;
285 // If the file has a length of zero, mmap might return a null pointer. In
286 // this case, allocate a single byte of memory and return it instead.
290 // mmap in the file all at once...
291 void *Buffer = (void*)mmap(0, Length, PROT_READ, MAP_PRIVATE, FD, 0);
293 if (Buffer == (void*)MAP_FAILED)
298 // FIXME: implement with read/write
303 /// UnmapFileFromAddressSpace - Remove the specified file from the current
305 void llvm::UnmapFileFromAddressSpace(void *Buffer, unsigned Length) {
306 #if defined(HAVE_MMAP_FILE) && !defined(_MSC_VER)
308 munmap((char*)Buffer, Length);
310 free(Buffer); // Zero byte files are malloc(1)'s.
316 //===----------------------------------------------------------------------===//
317 // FDHandle class implementation
320 FDHandle::~FDHandle() throw() {
321 if (FD != -1) close(FD);
324 FDHandle &FDHandle::operator=(int fd) throw() {
325 if (FD != -1) close(FD);