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9737492204
mapping of files. This first version uses mmap where its available. The class needs to implement an alternate mechanism based on malloc'd memory and file reading/writing for platforms without virtual memory. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16649 91177308-0d34-0410-b5e6-96231b3b80d8
139 lines
3.7 KiB
C++
139 lines
3.7 KiB
C++
//===- Unix/MappedFile.cpp - Unix MappedFile Implementation -----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Reid Spencer and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides the generic Unix implementation of the MappedFile concept.
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//
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//===----------------------------------------------------------------------===//
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//===----------------------------------------------------------------------===//
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//=== WARNING: Implementation here must contain only generic UNIX code that
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//=== is guaranteed to work on *all* UNIX variants.
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//===----------------------------------------------------------------------===//
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#include "llvm/System/Process.h"
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#include "Unix.h"
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#include <sys/fcntl.h>
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#include <sys/mman.h>
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namespace llvm {
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using namespace sys;
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struct sys::MappedFileInfo {
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int fd_;
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struct stat sbuf_;
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};
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void MappedFile::initialize() {
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if (path_.exists()) {
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info_ = new MappedFileInfo;
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int mode = 0;
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if (options_&READ_ACCESS)
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if (options_&WRITE_ACCESS)
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mode = O_RDWR;
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else
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mode = O_RDONLY;
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else if (options_&WRITE_ACCESS)
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mode = O_WRONLY;
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info_->fd_ = ::open(path_.c_str(),mode);
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if (info_->fd_ < 0) {
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delete info_;
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info_ = 0;
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ThrowErrno(std::string("Can't open file: ") + path_.get());
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}
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struct stat sbuf;
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if(::fstat(info_->fd_, &info_->sbuf_) < 0) {
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::close(info_->fd_);
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delete info_;
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info_ = 0;
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ThrowErrno(std::string("Can't stat file: ") + path_.get());
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}
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}
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}
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void MappedFile::terminate() {
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assert(info_ && "MappedFile not initialized");
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if (info_->fd_ >= 0)
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::close(info_->fd_);
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delete info_;
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info_ = 0;
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}
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void MappedFile::unmap() {
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assert(info_ && "MappedFile not initialized");
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if (isMapped()) {
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if (options_ & WRITE_ACCESS)
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::msync(base_, info_->sbuf_.st_size, MS_SYNC);
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::munmap(base_, info_->sbuf_.st_size);
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}
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}
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void* MappedFile::map() {
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if (!isMapped()) {
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int prot = PROT_NONE;
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int flags = MAP_FILE;
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if (options_ == 0) {
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prot = PROT_READ;
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flags = MAP_PRIVATE;
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} else {
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if (options_ & READ_ACCESS)
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prot |= PROT_READ;
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if (options_ & WRITE_ACCESS)
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prot |= PROT_WRITE;
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if (options_ & EXEC_ACCESS)
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prot |= PROT_EXEC;
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if (options_ & SHARED_MAPPING)
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flags |= MAP_SHARED;
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else
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flags |= MAP_PRIVATE;
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}
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size_t map_size = ((info_->sbuf_.st_size / Process::GetPageSize())+1) *
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Process::GetPageSize();
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base_ = ::mmap(0, map_size, prot, flags, info_->fd_, 0);
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if (base_ == MAP_FAILED)
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ThrowErrno(std::string("Can't map file:") + path_.get());
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}
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return base_;
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}
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size_t MappedFile::size() {
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assert(info_ && "MappedFile not initialized");
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return info_->sbuf_.st_size;
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}
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void MappedFile::size(size_t new_size) {
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assert(info_ && "MappedFile not initialized");
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// Take the mapping out of memory
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this->unmap();
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// Adjust the current size to a page boundary
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size_t cur_size = ((info_->sbuf_.st_size / Process::GetPageSize())+1) *
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Process::GetPageSize();
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// Adjust the new_size to a page boundary
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new_size = ((new_size / Process::GetPageSize())+1) *
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Process::GetPageSize();
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// If the file needs to be extended
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if (new_size > cur_size) {
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// Ensure we can allocate at least the idodes necessary to handle the
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// file size requested.
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::lseek(info_->fd_, new_size, SEEK_SET);
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::write(info_->fd_, "\0", 1);
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}
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// Seek to current end of file.
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this->map();
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}
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}
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// vim: sw=2 smartindent smarttab tw=80 autoindent expandtab
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