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//===- Support/FileUtilities.cpp - File System Utilities ------------------===//
//
// This file implements a family of utility functions which are useful for doing
// various things with files.
//
//===----------------------------------------------------------------------===//
#include "Support/FileUtilities.h"
#include "Config/unistd.h"
#include "Config/sys/stat.h"
#include "Config/sys/types.h"
#include <fstream>
#include <iostream>
#include <cstdio>
/// 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 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;
}
/// 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 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 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 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....
int TempFD;
if ((TempFD = mkstemp(FNBuffer)) == -1) {
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);
std::string Result(FNBuffer);
delete[] FNBuffer;
return Result;
}
///
/// Method: MakeFileExecutable ()
///
/// Description:
/// This method makes the specified filename executable by giving it
/// execute permission. It respects the umask value of the process, and it
/// does not enable any unnecessary access bits.
///
/// Algorithm:
/// o Get file's current permissions.
/// o Get the process's current umask.
/// o Take the set of all execute bits and disable those found in the umask.
/// o Add the remaining permissions to the file's permissions.
///
bool
MakeFileExecutable (const std::string & Filename)
{
// Permissions masking value of the user
mode_t mask;
// Permissions currently enabled on the file
struct stat fstat;
//
// Grab the umask value from the operating system. We want to use it when
// changing the file's permissions.
//
// Note:
// Umask() is one of those annoying system calls. You have to call it
// to get the current value and then set it back.
//
mask = umask (0x777);
umask (mask);
//
// Go fetch the file's current permission bits. We want to *add* execute
// access to the file.
//
if ((stat (Filename.c_str(), &fstat)) == -1)
{
return false;
}
//
// Make the file executable...
//
if ((chmod(Filename.c_str(), (fstat.st_mode | (0111 & ~mask)))) == -1)
{
return false;
}
return true;
}
///
/// Method: MakeFileReadable ()
///
/// Description:
/// This method makes the specified filename readable by giving it
/// read permission. It respects the umask value of the process, and it
/// does not enable any unnecessary access bits.
///
/// Algorithm:
/// o Get file's current permissions.
/// o Get the process's current umask.
/// o Take the set of all read bits and disable those found in the umask.
/// o Add the remaining permissions to the file's permissions.
///
bool
MakeFileReadable (const std::string & Filename)
{
// Permissions masking value of the user
mode_t mask;
// Permissions currently enabled on the file
struct stat fstat;
//
// Grab the umask value from the operating system. We want to use it when
// changing the file's permissions.
//
// Note:
// Umask() is one of those annoying system calls. You have to call it
// to get the current value and then set it back.
//
mask = umask (0x777);
umask (mask);
//
// Go fetch the file's current permission bits. We want to *add* execute
// access to the file.
//
if ((stat (Filename.c_str(), &fstat)) == -1)
{
return false;
}
//
// Make the file executable...
//
if ((chmod(Filename.c_str(), (fstat.st_mode | (0444 & ~mask)))) == -1)
{
return false;
}
return true;
}
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