llvm-6502/lib/Support/FileUtilities.cpp

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//===- Support/FileUtilities.cpp - File System Utilities ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a family of utility functions which are useful for doing
// various things with files.
//
//===----------------------------------------------------------------------===//
#include "Support/FileUtilities.h"
#include "Support/DataTypes.h"
#include "Config/unistd.h"
#include "Config/fcntl.h"
#include "Config/sys/types.h"
#include "Config/sys/stat.h"
#include "Config/sys/mman.h"
#include "Config/alloca.h"
#include <cerrno>
#include <cstdio>
#include <fstream>
#include <iostream>
using namespace llvm;
/// CheckMagic - Returns true IFF the file named FN begins with Magic. FN must
/// name a readable file.
///
bool llvm::CheckMagic(const std::string &FN, const std::string &Magic) {
char *buf = (char*)alloca(1 + Magic.size());
std::ifstream f(FN.c_str());
f.read(buf, Magic.size());
buf[Magic.size()] = '\0';
return Magic == buf;
}
/// IsArchive - Returns true IFF the file named FN appears to be a "ar" library
/// archive. The file named FN must exist.
///
bool llvm::IsArchive(const std::string &FN) {
// Inspect the beginning of the file to see if it contains the "ar"
// library archive format magic string.
return CheckMagic(FN, "!<arch>\012");
}
/// IsBytecode - Returns true IFF the file named FN appears to be an LLVM
/// bytecode file. The file named FN must exist.
///
bool llvm::IsBytecode(const std::string &FN) {
// Inspect the beginning of the file to see if it contains the LLVM
// bytecode format magic string.
return CheckMagic (FN, "llvm");
}
/// IsSharedObject - Returns trus IFF the file named FN appears to be a shared
/// object with an ELF header. The file named FN must exist.
///
bool llvm::IsSharedObject(const std::string &FN) {
// Inspect the beginning of the file to see if it contains the ELF shared
// object magic string.
static const char elfMagic[] = { 0x7f, 'E', 'L', 'F', '\0' };
return CheckMagic(FN, elfMagic);
}
/// FileOpenable - Returns true IFF Filename names an existing regular
/// file which we can successfully open.
///
bool llvm::FileOpenable(const std::string &Filename) {
struct stat s;
if (stat (Filename.c_str (), &s) == -1)
return false; // Cannot stat file
if (!S_ISREG (s.st_mode))
return false; // File is not a regular file
std::ifstream FileStream (Filename.c_str ());
if (!FileStream)
return false; // File is not openable
return true;
}
/// DiffFiles - Compare the two files specified, returning true if they are
/// different or if there is a file error. If you specify a string to fill in
/// for the error option, it will set the string to an error message if an error
/// occurs, allowing the caller to distinguish between a failed diff and a file
/// system error.
///
bool llvm::DiffFiles(const std::string &FileA, const std::string &FileB,
std::string *Error) {
std::ifstream FileAStream(FileA.c_str());
if (!FileAStream) {
if (Error) *Error = "Couldn't open file '" + FileA + "'";
return true;
}
std::ifstream FileBStream(FileB.c_str());
if (!FileBStream) {
if (Error) *Error = "Couldn't open file '" + FileB + "'";
return true;
}
// Compare the two files...
int C1, C2;
do {
C1 = FileAStream.get();
C2 = FileBStream.get();
if (C1 != C2) return true;
} while (C1 != EOF);
return false;
}
/// CopyFile - Copy the specified source file to the specified destination,
/// overwriting destination if it exists. This returns true on failure.
///
bool llvm::CopyFile(const std::string &Dest, const std::string &Src) {
FDHandle InFD(open(Src.c_str(), O_RDONLY));
if (InFD == -1) return true;
FileRemover FR(Dest);
FDHandle OutFD(open(Dest.c_str(), O_WRONLY|O_CREAT, 0666));
if (OutFD == -1) return true;
char Buffer[16*1024];
while (ssize_t Amt = read(InFD, Buffer, 16*1024)) {
if (Amt == -1) {
if (errno != EINTR) return true; // Error reading the file.
} else {
char *BufPtr = Buffer;
while (Amt) {
ssize_t AmtWritten = write(OutFD, BufPtr, Amt);
if (AmtWritten == -1) {
if (errno != EINTR) return true; // Error writing the file.
} else {
Amt -= AmtWritten;
BufPtr += AmtWritten;
}
}
}
}
FR.releaseFile(); // Success!
return false;
}
/// MoveFileOverIfUpdated - If the file specified by New is different than Old,
/// or if Old does not exist, move the New file over the Old file. Otherwise,
/// remove the New file.
///
void llvm::MoveFileOverIfUpdated(const std::string &New,
const std::string &Old) {
if (DiffFiles(New, Old)) {
if (std::rename(New.c_str(), Old.c_str()))
std::cerr << "Error renaming '" << New << "' to '" << Old << "'!\n";
} else {
std::remove(New.c_str());
}
}
/// removeFile - Delete the specified file
///
void llvm::removeFile(const std::string &Filename) {
std::remove(Filename.c_str());
}
/// getUniqueFilename - Return a filename with the specified prefix. If the
/// file does not exist yet, return it, otherwise add a suffix to make it
/// unique.
///
std::string llvm::getUniqueFilename(const std::string &FilenameBase) {
if (!std::ifstream(FilenameBase.c_str()))
return FilenameBase; // Couldn't open the file? Use it!
// Create a pattern for mkstemp...
char *FNBuffer = new char[FilenameBase.size()+8];
strcpy(FNBuffer, FilenameBase.c_str());
strcpy(FNBuffer+FilenameBase.size(), "-XXXXXX");
// Agree on a temporary file name to use....
#if defined(HAVE_MKSTEMP) && !defined(_MSC_VER)
int TempFD;
if ((TempFD = mkstemp(FNBuffer)) == -1) {
// FIXME: this should return an emtpy string or something and allow the
// caller to deal with the error!
std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
<< " directory!\n";
exit(1);
}
// We don't need to hold the temp file descriptor... we will trust that no one
// will overwrite/delete the file while we are working on it...
close(TempFD);
#else
// If we don't have mkstemp, use the old and obsolete mktemp function.
if (mktemp(FNBuffer) == 0) {
// FIXME: this should return an emtpy string or something and allow the
// caller to deal with the error!
std::cerr << "bugpoint: ERROR: Cannot create temporary file in the current "
<< " directory!\n";
exit(1);
}
#endif
std::string Result(FNBuffer);
delete[] FNBuffer;
return Result;
}
static bool AddPermissionsBits (const std::string &Filename, int bits) {
// Get the umask value from the operating system. We want to use it
// when changing the file's permissions. Since calling umask() sets
// the umask and returns its old value, we must call it a second
// time to reset it to the user's preference.
int mask = umask(0777); // The arg. to umask is arbitrary.
umask(mask); // Restore the umask.
// Get the file's current mode.
struct stat st;
if ((stat(Filename.c_str(), &st)) == -1)
return false;
// Change the file to have whichever permissions bits from 'bits'
// that the umask would not disable.
if ((chmod(Filename.c_str(), (st.st_mode | (bits & ~mask)))) == -1)
return false;
return true;
}
/// MakeFileExecutable - Make the file named Filename executable by
/// setting whichever execute permissions bits the process's current
/// umask would allow. Filename must name an existing file or
/// directory. Returns true on success, false on error.
///
bool llvm::MakeFileExecutable(const std::string &Filename) {
return AddPermissionsBits(Filename, 0111);
}
/// MakeFileReadable - Make the file named Filename readable by
/// setting whichever read permissions bits the process's current
/// umask would allow. Filename must name an existing file or
/// directory. Returns true on success, false on error.
///
bool llvm::MakeFileReadable(const std::string &Filename) {
return AddPermissionsBits(Filename, 0444);
}
/// getFileSize - Return the size of the specified file in bytes, or -1 if the
/// file cannot be read or does not exist.
long long llvm::getFileSize(const std::string &Filename) {
struct stat StatBuf;
if (stat(Filename.c_str(), &StatBuf) == -1)
return -1;
return StatBuf.st_size;
}
/// getFileTimestamp - Get the last modified time for the specified file in an
/// unspecified format. This is useful to allow checking to see if a file was
/// updated since that last time the timestampt was aquired. If the file does
/// not exist or there is an error getting the time-stamp, zero is returned.
unsigned long long llvm::getFileTimestamp(const std::string &Filename) {
struct stat StatBuf;
if (stat(Filename.c_str(), &StatBuf) == -1)
return 0;
return StatBuf.st_mtime;
}
/// ReadFileIntoAddressSpace - Attempt to map the specific file into the
/// address space of the current process for reading. If this succeeds,
/// return the address of the buffer and the length of the file mapped. On
/// failure, return null.
void *llvm::ReadFileIntoAddressSpace(const std::string &Filename,
unsigned &Length) {
#if defined(HAVE_MMAP_FILE) && !defined(_MSC_VER)
Length = (unsigned)getFileSize(Filename);
if ((int)Length == -1) return 0;
FDHandle FD(open(Filename.c_str(), O_RDONLY));
if (FD == -1) return 0;
// If the file has a length of zero, mmap might return a null pointer. In
// this case, allocate a single byte of memory and return it instead.
if (Length == 0)
return malloc(1);
// mmap in the file all at once...
void *Buffer = (void*)mmap(0, Length, PROT_READ, MAP_PRIVATE, FD, 0);
if (Buffer == (void*)MAP_FAILED)
return 0;
return Buffer;
#else
// FIXME: implement with read/write
return 0;
#endif
}
/// UnmapFileFromAddressSpace - Remove the specified file from the current
/// address space.
void llvm::UnmapFileFromAddressSpace(void *Buffer, unsigned Length) {
#if defined(HAVE_MMAP_FILE) && !defined(_MSC_VER)
if (Length)
munmap((char*)Buffer, Length);
else
free(Buffer); // Zero byte files are malloc(1)'s.
#else
free(Buffer);
#endif
}
//===----------------------------------------------------------------------===//
// FDHandle class implementation
//
FDHandle::~FDHandle() throw() {
if (FD != -1) close(FD);
}
FDHandle &FDHandle::operator=(int fd) throw() {
if (FD != -1) close(FD);
FD = fd;
return *this;
}