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//===- Unix/MappedFile.cpp - Unix MappedFile Implementation -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and 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 "llvm/System/Process.h"
#include "Unix.h"
#include <fcntl.h>
#include <sys/mman.h>
namespace llvm {
using namespace sys;
struct sys::MappedFileInfo {
int fd_;
struct stat sbuf_;
};
void MappedFile::initialize() {
if (path_.exists()) {
info_ = new MappedFileInfo;
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;
info_->fd_ = ::open(path_.c_str(),mode);
if (info_->fd_ < 0) {
delete info_;
info_ = 0;
ThrowErrno(std::string("Can't open file: ") + path_.toString());
}
struct stat sbuf;
if(::fstat(info_->fd_, &info_->sbuf_) < 0) {
::close(info_->fd_);
delete info_;
info_ = 0;
ThrowErrno(std::string("Can't stat file: ") + path_.toString());
}
} else {
throw std::string("Can't open file: ") + path_.toString();
}
}
void MappedFile::terminate() {
assert(info_ && "MappedFile not initialized");
if (info_->fd_ >= 0)
::close(info_->fd_);
delete info_;
info_ = 0;
}
void MappedFile::unmap() {
assert(info_ && "MappedFile not initialized");
if (isMapped()) {
if (options_ & WRITE_ACCESS)
::msync(base_, info_->sbuf_.st_size, MS_SYNC);
::munmap(base_, info_->sbuf_.st_size);
}
}
void* MappedFile::map() {
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_->sbuf_.st_size / Process::GetPageSize())+1) *
Process::GetPageSize();
base_ = ::mmap(0, map_size, prot, flags, info_->fd_, 0);
if (base_ == MAP_FAILED)
ThrowErrno(std::string("Can't map file:") + path_.toString());
}
return base_;
}
size_t MappedFile::size() {
assert(info_ && "MappedFile not initialized");
return info_->sbuf_.st_size;
}
void MappedFile::size(size_t new_size) {
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_->sbuf_.st_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.
::lseek(info_->fd_, new_size, SEEK_SET);
::write(info_->fd_, "\0", 1);
}
// Seek to current end of file.
this->map();
}
}
// vim: sw=2 smartindent smarttab tw=80 autoindent expandtab
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