fd_array.cc

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/*
 * Copyright (c) 2016 Advanced Micro Devices, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 * this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the copyright holder nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
 
#include "sim/fd_array.hh"
 
#include <fcntl.h>
#include <unistd.h>
 
#include <array>
#include <memory>
#include <string>
 
#include "base/logging.hh"
#include "base/output.hh"
#include "params/Process.hh"
#include "sim/fd_entry.hh"
 
namespace gem5
{
 
FDArray::FDArray(std::string const& input, std::string const& output,
                 std::string const& errout)
    :  _fdArray(), _input(input), _output(output), _errout(errout),
      _imap {{"",       -1},
             {"cin",    STDIN_FILENO},
             {"stdin",  STDIN_FILENO}},
      _oemap{{"",       -1},
             {"cout",   STDOUT_FILENO},
             {"stdout", STDOUT_FILENO},
             {"cerr",   STDERR_FILENO},
             {"stderr", STDERR_FILENO}}
{
    int sim_fd;
    std::map<std::string, int>::iterator it;
 
    if ((it = _imap.find(input)) != _imap.end())
        sim_fd = it->second;
    else
        sim_fd = openInputFile(input);
 
    auto ffd = std::make_shared<FileFDEntry>(sim_fd, O_RDONLY, input, false);
    _fdArray[STDIN_FILENO] = ffd;
 
    if ((it = _oemap.find(output)) != _oemap.end())
        sim_fd = it->second;
    else
        sim_fd = openOutputFile(output);
 
    ffd = std::make_shared<FileFDEntry>(sim_fd, O_WRONLY | O_CREAT | O_TRUNC,
                                        output, false);
    _fdArray[STDOUT_FILENO] = ffd;
 
    if (output == errout)
        ; /* Reuse the same file descriptor if these match. */
    else if ((it = _oemap.find(errout)) != _oemap.end())
        sim_fd = it->second;
    else
        sim_fd = openOutputFile(errout);
 
    ffd = std::make_shared<FileFDEntry>(sim_fd, O_WRONLY | O_CREAT | O_TRUNC,
                                        errout, false);
    _fdArray[STDERR_FILENO] = ffd;
}
 
void
FDArray::updateFileOffsets()
{
    for (auto& fdp : _fdArray) {
        auto ffd = std::dynamic_pointer_cast<FileFDEntry>(fdp);
 
        if (!ffd)
            continue;
 
        int sim_fd = ffd->getSimFD();
        ffd->setFileOffset(lseek(sim_fd, 0, SEEK_CUR));
    }
}
 
void
FDArray::restoreFileOffsets()
{
    auto seek = [] (std::shared_ptr<FileFDEntry> ffd)
    {
        if (lseek(ffd->getSimFD(), ffd->getFileOffset(), SEEK_SET) < 0)
            fatal("Unable to seek to location in %s", ffd->getFileName());
    };
 
    std::map<std::string, int>::iterator it;
 
    std::shared_ptr<FDEntry> stdin_fde = _fdArray[STDIN_FILENO];
    auto stdin_ffd = std::dynamic_pointer_cast<FileFDEntry>(stdin_fde);
 
    if (_input != stdin_ffd->getFileName()) {
        warn("Using new input file (%s) rather than checkpointed (%s)\n",
             _input, stdin_ffd->getFileName());
        stdin_ffd->setFileName(_input);
        stdin_ffd->setFileOffset(0);
    }
 
    if ((it = _imap.find(stdin_ffd->getFileName())) != _imap.end()) {
        stdin_ffd->setSimFD(it->second);
    } else {
        stdin_ffd->setSimFD(openInputFile(stdin_ffd->getFileName()));
        seek(stdin_ffd);
    }
 
    std::shared_ptr<FDEntry> stdout_fde = _fdArray[STDOUT_FILENO];
    auto stdout_ffd = std::dynamic_pointer_cast<FileFDEntry>(stdout_fde);
 
    if (_output != stdout_ffd->getFileName()) {
        warn("Using new output file (%s) rather than checkpointed (%s)\n",
             _output, stdout_ffd->getFileName());
        stdout_ffd->setFileName(_output);
        stdout_ffd->setFileOffset(0);
    }
 
    if ((it = _oemap.find(stdout_ffd->getFileName())) != _oemap.end()) {
        stdout_ffd->setSimFD(it->second);
    } else {
        stdout_ffd->setSimFD(openOutputFile(stdout_ffd->getFileName()));
        seek(stdout_ffd);
    }
 
    std::shared_ptr<FDEntry> stderr_fde = _fdArray[STDERR_FILENO];
    auto stderr_ffd = std::dynamic_pointer_cast<FileFDEntry>(stderr_fde);
 
    if (_errout != stderr_ffd->getFileName()) {
        warn("Using new error file (%s) rather than checkpointed (%s)\n",
             _errout, stderr_ffd->getFileName());
        stderr_ffd->setFileName(_errout);
        stderr_ffd->setFileOffset(0);
    }
 
    if (stdout_ffd->getFileName() == stderr_ffd->getFileName()) {
        /* Reuse the same sim_fd file descriptor if these match. */
        stderr_ffd->setSimFD(stdout_ffd->getSimFD());
    } else if ((it = _oemap.find(stderr_ffd->getFileName())) != _oemap.end()) {
        stderr_ffd->setSimFD(it->second);
    } else {
        stderr_ffd->setSimFD(openOutputFile(stderr_ffd->getFileName()));
        seek(stderr_ffd);
    }
 
    for (int tgt_fd = 3; tgt_fd < _fdArray.size(); tgt_fd++) {
        std::shared_ptr<FDEntry> fdp = _fdArray[tgt_fd];
        if (!fdp)
            continue;
 
        /* Need to reconnect pipe ends. */
        if (auto pfd = std::dynamic_pointer_cast<PipeFDEntry>(fdp)) {
            if (pfd->getEndType() == PipeFDEntry::EndType::write)
                continue;
 
            /* Setup the pipe or fatal out of the simulation. */
            int fd_pair[2];
            if (pipe(fd_pair) < 0)
                fatal("Unable to create new pipe");
 
            pfd->setSimFD(fd_pair[0]);
 
            int prs = pfd->getPipeReadSource();
            std::shared_ptr<FDEntry> write_fdp = _fdArray[prs];
 
            /* Now cast it and make sure that we are still sane. */
            auto write_pfd = std::dynamic_pointer_cast<PipeFDEntry>(write_fdp);
 
            /* Hook up the write end back to the right side of the pipe. */
            write_pfd->setSimFD(fd_pair[1]);
        }
 
        /* Need to reassign 'driver'. */
        if (auto dfd = std::dynamic_pointer_cast<DeviceFDEntry>(fdp)) {
            fatal("Unable to restore checkpoints with emulated drivers");
        }
 
        /* Need to open files and seek. */
        if (auto ffd = std::dynamic_pointer_cast<FileFDEntry>(fdp)) {
            int sim_fd = openFile(ffd->getFileName(), ffd->getFlags(), 0664);
            ffd->setSimFD(sim_fd);
            seek(ffd);
        }
    }
}
 
int
FDArray::allocFD(std::shared_ptr<FDEntry> in)
{
    for (int i = 0; i < _fdArray.size(); i++) {
        std::shared_ptr<FDEntry> fdp = _fdArray[i];
        if (!fdp) {
            _fdArray[i] = in;
            return i;
        }
    }
    fatal("Out of target file descriptors");
}
 
int
FDArray::openFile(std::string const& filename, int flags, mode_t mode) const
{
    int sim_fd = open(filename.c_str(), flags, mode);
    if (sim_fd != -1)
        return sim_fd;
    fatal("Unable to open %s with mode %d", filename, mode);
}
 
int
FDArray::openInputFile(std::string const& filename) const
{
    return openFile(filename, O_RDONLY, 00);
}
 
int
FDArray::openOutputFile(std::string const& filename) const
{
    return openFile(simout.resolve(filename),
                    O_WRONLY | O_CREAT | O_TRUNC, 0664);
}
 
std::shared_ptr<FDEntry>
FDArray::getFDEntry(int tgt_fd)
{
    assert(0 <= tgt_fd && tgt_fd < _fdArray.size());
    return _fdArray[tgt_fd];
}
 
void
FDArray::setFDEntry(int tgt_fd, std::shared_ptr<FDEntry> fdep)
{
    assert(0 <= tgt_fd && tgt_fd < _fdArray.size());
    _fdArray[tgt_fd] = fdep;
}
 
int
FDArray::closeFDEntry(int tgt_fd)
{
    if (tgt_fd >= _fdArray.size() || tgt_fd < 0)
        return -EBADF;
 
    int sim_fd = -1;
    auto hbfdp = std::dynamic_pointer_cast<HBFDEntry>(_fdArray[tgt_fd]);
    if (hbfdp)
        sim_fd = hbfdp->getSimFD();
 
    int status = 0;
    if (sim_fd > 2)
        status = close(sim_fd);
 
    if (status == 0)
        _fdArray[tgt_fd] = nullptr;
 
    return status;
}
 
void
FDArray::serialize(CheckpointOut &cp) const {
    ScopedCheckpointSection sec(cp, "fdarray");
    paramOut(cp, "size", _fdArray.size());
    for (int tgt_fd = 0; tgt_fd < _fdArray.size(); tgt_fd++) {
        auto fd = _fdArray[tgt_fd];
        ScopedCheckpointSection sec(cp, csprintf("Entry%d", tgt_fd));
        if (!fd) {
            paramOut(cp, "class", FDEntry::FDClass::fd_null);
            continue;
        }
        paramOut(cp, "class", fd->getClass());
        fd->serialize(cp);
    }
}
 
void
FDArray::unserialize(CheckpointIn &cp) {
    ScopedCheckpointSection sec(cp, "fdarray");
    uint64_t size;
    paramIn(cp, "size", size);
    assert(_fdArray.size() == size &&
            "FDArray sizes do not match at unserialize!");
 
    for (int tgt_fd = 0; tgt_fd < _fdArray.size(); tgt_fd++) {
        if (tgt_fd == STDIN_FILENO || tgt_fd == STDOUT_FILENO ||
                tgt_fd == STDERR_FILENO)
            continue;
        ScopedCheckpointSection sec(cp, csprintf("Entry%d", tgt_fd));
        FDEntry::FDClass fd_class;
        paramIn(cp, "class", fd_class);
        std::shared_ptr<FDEntry> fdep;
 
        switch (fd_class) {
            case FDEntry::FDClass::fd_base:
                panic("Abstract fd entry was serialized");
                break;
            case FDEntry::FDClass::fd_hb:
                fdep = std::make_shared<HBFDEntry>(0, 0);
                break;
            case FDEntry::FDClass::fd_file:
                fdep = std::make_shared<FileFDEntry>(0, 0, "", 0, 00);
                break;
            case FDEntry::FDClass::fd_device:
                fdep = std::make_shared<DeviceFDEntry>(nullptr, "");
                break;
            case FDEntry::FDClass::fd_pipe:
                fdep = std::make_shared<PipeFDEntry>(
                        0, 0, PipeFDEntry::EndType::read);
                break;
            case FDEntry::FDClass::fd_socket:
                fdep = std::make_shared<SocketFDEntry>(0, 0, 0, 0);
                break;
            case FDEntry::FDClass::fd_null:
                continue;
            default:
                panic("Unrecognized fd class");
                break;
        }
 
        fdep->unserialize(cp);
 
        auto this_ffd = std::dynamic_pointer_cast<FileFDEntry>(fdep);
        if (!this_ffd)
            continue;
        setFDEntry(tgt_fd, fdep);
 
        mode_t mode = this_ffd->getFileMode();
        std::string const& path = this_ffd->getFileName();
        int flags = this_ffd->getFlags();
 
        // Re-open the file and assign a new sim_fd
        int sim_fd = openFile(path, flags, mode);
        this_ffd->setSimFD(sim_fd);
 
        // Restore the file offset to the proper value
        uint64_t file_offset = this_ffd->getFileOffset();
        lseek(sim_fd, file_offset, SEEK_SET);
    }
}
 
} // namespace gem5