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//===- Unix/MappedFile.cpp - Unix MappedFile Implementation -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file provides the generic Unix implementation of the MappedFile concept.
//
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only generic UNIX code that
//=== is guaranteed to work on *all* UNIX variants.
//===----------------------------------------------------------------------===//
#include "Unix.h"
#include "llvm/System/Process.h"
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
namespace llvm {
using namespace sys;
struct sys::MappedFileInfo {
int FD;
off_t Size;
};
bool MappedFile::initialize(std::string* ErrMsg) {
int mode = 0;
if (options_ & READ_ACCESS)
if (options_ & WRITE_ACCESS)
mode = O_RDWR;
else
mode = O_RDONLY;
else if (options_ & WRITE_ACCESS)
mode = O_WRONLY;
int FD = ::open(path_.c_str(), mode);
if (FD < 0) {
MakeErrMsg(ErrMsg, "can't open file '" + path_.toString() + "'");
return true;
}
const FileStatus *Status = path_.getFileStatus(false, ErrMsg);
if (!Status) {
::close(FD);
return true;
}
info_ = new MappedFileInfo;
info_->FD = FD;
info_->Size = Status->getSize();
return false;
}
void MappedFile::terminate() {
assert(info_ && "MappedFile not initialized");
::close(info_->FD);
delete info_;
info_ = 0;
}
void MappedFile::unmap() {
assert(info_ && "MappedFile not initialized");
if (isMapped()) {
if (options_ & WRITE_ACCESS)
::msync(base_, info_->Size, MS_SYNC);
::munmap(base_, info_->Size);
base_ = 0; // Mark this as non-mapped.
}
}
void* MappedFile::map(std::string* ErrMsg) {
assert(info_ && "MappedFile not initialized");
if (!isMapped()) {
int prot = PROT_NONE;
int flags = 0;
#ifdef MAP_FILE
flags |= MAP_FILE;
#endif
if (options_ == 0) {
prot = PROT_READ;
flags = MAP_PRIVATE;
} else {
if (options_ & READ_ACCESS)
prot |= PROT_READ;
if (options_ & WRITE_ACCESS)
prot |= PROT_WRITE;
if (options_ & EXEC_ACCESS)
prot |= PROT_EXEC;
if (options_ & SHARED_MAPPING)
flags |= MAP_SHARED;
else
flags |= MAP_PRIVATE;
}
size_t map_size = ((info_->Size / Process::GetPageSize())+1) *
Process::GetPageSize();
base_ = ::mmap(0, map_size, prot, flags, info_->FD, 0);
if (base_ == MAP_FAILED) {
MakeErrMsg(ErrMsg, "Can't map file:" + path_.toString());
return 0;
}
}
return base_;
}
size_t MappedFile::size() const {
assert(info_ && "MappedFile not initialized");
return info_->Size;
}
bool MappedFile::size(size_t new_size, std::string* ErrMsg) {
assert(info_ && "MappedFile not initialized");
// Take the mapping out of memory
this->unmap();
// Adjust the current size to a page boundary
size_t cur_size = ((info_->Size / Process::GetPageSize())+1) *
Process::GetPageSize();
// Adjust the new_size to a page boundary
new_size = ((new_size / Process::GetPageSize())+1) *
Process::GetPageSize();
// If the file needs to be extended
if (new_size > cur_size) {
// Ensure we can allocate at least the idodes necessary to handle the
// file size requested.
if ((off_t)-1 == ::lseek(info_->FD, new_size, SEEK_SET))
return MakeErrMsg(ErrMsg, "Can't lseek: ");
if (-1 == ::write(info_->FD, "\0", 1))
return MakeErrMsg(ErrMsg, "Can't write: ");
}
// Put the mapping back into memory.
return this->map(ErrMsg);
}
}
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