xref: /gem5/src/sim/process.cc

/*
 * Copyright (c) 2014 Advanced Micro Devices, Inc.
 * Copyright (c) 2012 ARM Limited
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * Copyright (c) 2001-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * 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;
 * neither the name of the copyright holders 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
 * OWNER 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.
 *
 * Authors: Nathan Binkert
 *          Steve Reinhardt
 *          Ali Saidi
 */

#include <fcntl.h>
#include <unistd.h>

#include <cstdio>
#include <string>

#include "base/loader/object_file.hh"
#include "base/loader/symtab.hh"
#include "base/intmath.hh"
#include "base/statistics.hh"
#include "config/the_isa.hh"
#include "cpu/thread_context.hh"
#include "mem/page_table.hh"
#include "mem/multi_level_page_table.hh"
#include "mem/se_translating_port_proxy.hh"
#include "params/LiveProcess.hh"
#include "params/Process.hh"
#include "sim/debug.hh"
#include "sim/process.hh"
#include "sim/process_impl.hh"
#include "sim/stats.hh"
#include "sim/syscall_emul.hh"
#include "sim/system.hh"

#if THE_ISA == ALPHA_ISA
#include "arch/alpha/linux/process.hh"
#include "arch/alpha/tru64/process.hh"
#elif THE_ISA == SPARC_ISA
#include "arch/sparc/linux/process.hh"
#include "arch/sparc/solaris/process.hh"
#elif THE_ISA == MIPS_ISA
#include "arch/mips/linux/process.hh"
#elif THE_ISA == ARM_ISA
#include "arch/arm/linux/process.hh"
#include "arch/arm/freebsd/process.hh"
#elif THE_ISA == X86_ISA
#include "arch/x86/linux/process.hh"
#elif THE_ISA == POWER_ISA
#include "arch/power/linux/process.hh"
#else
#error "THE_ISA not set"
#endif


using namespace std;
using namespace TheISA;

// current number of allocated processes
int num_processes = 0;

template<class IntType>
AuxVector<IntType>::AuxVector(IntType type, IntType val)
{
    a_type = TheISA::htog(type);
    a_val = TheISA::htog(val);
}

template struct AuxVector<uint32_t>;
template struct AuxVector<uint64_t>;

Process::Process(ProcessParams * params)
    : SimObject(params), system(params->system),
      brk_point(0), stack_base(0), stack_size(0), stack_min(0),
      max_stack_size(params->max_stack_size),
      next_thread_stack_base(0),
      M5_pid(system->allocatePID()),
      useArchPT(params->useArchPT),
      kvmInSE(params->kvmInSE),
      pTable(useArchPT ?
        static_cast<PageTableBase *>(new ArchPageTable(name(), M5_pid, system)) :
        static_cast<PageTableBase *>(new FuncPageTable(name(), M5_pid)) ),
      initVirtMem(system->getSystemPort(), this,
                  SETranslatingPortProxy::Always),
      fd_map(new FdMap[NUM_FDS])
{
    string in = params->input;
    string out = params->output;
    string err = params->errout;

    // initialize file descriptors to default: same as simulator
    int stdin_fd, stdout_fd, stderr_fd;

    if (in == "stdin" || in == "cin")
        stdin_fd = STDIN_FILENO;
    else if (in == "None")
        stdin_fd = -1;
    else
        stdin_fd = Process::openInputFile(in);

    if (out == "stdout" || out == "cout")
        stdout_fd = STDOUT_FILENO;
    else if (out == "stderr" || out == "cerr")
        stdout_fd = STDERR_FILENO;
    else if (out == "None")
        stdout_fd = -1;
    else
        stdout_fd = Process::openOutputFile(out);

    if (err == "stdout" || err == "cout")
        stderr_fd = STDOUT_FILENO;
    else if (err == "stderr" || err == "cerr")
        stderr_fd = STDERR_FILENO;
    else if (err == "None")
        stderr_fd = -1;
    else if (err == out)
        stderr_fd = stdout_fd;
    else
        stderr_fd = Process::openOutputFile(err);

    // initialize first 3 fds (stdin, stdout, stderr)
    Process::FdMap *fdo = &fd_map[STDIN_FILENO];
    fdo->fd = stdin_fd;
    fdo->filename = in;
    fdo->flags = O_RDONLY;
    fdo->mode = -1;
    fdo->fileOffset = 0;

    fdo =  &fd_map[STDOUT_FILENO];
    fdo->fd = stdout_fd;
    fdo->filename = out;
    fdo->flags =  O_WRONLY | O_CREAT | O_TRUNC;
    fdo->mode = 0774;
    fdo->fileOffset = 0;

    fdo = &fd_map[STDERR_FILENO];
    fdo->fd = stderr_fd;
    fdo->filename = err;
    fdo->flags = O_WRONLY;
    fdo->mode = -1;
    fdo->fileOffset = 0;


    // mark remaining fds as free
    for (int i = 3; i < NUM_FDS; ++i) {
        fdo = &fd_map[i];
        fdo->fd = -1;
    }

    mmap_start = mmap_end = 0;
    nxm_start = nxm_end = 0;
    // other parameters will be initialized when the program is loaded
}


void
Process::regStats()
{
    using namespace Stats;

    num_syscalls
        .name(name() + ".num_syscalls")
        .desc("Number of system calls")
        ;
}

//
// static helper functions
//

int
Process::openInputFile(const string &filename)
{
    int fd = open(filename.c_str(), O_RDONLY);

    if (fd == -1) {
        perror(NULL);
        cerr << "unable to open \"" << filename << "\" for reading\n";
        fatal("can't open input file");
    }

    return fd;
}


int
Process::openOutputFile(const string &filename)
{
    int fd = open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC, 0664);

    if (fd == -1) {
        perror(NULL);
        cerr << "unable to open \"" << filename << "\" for writing\n";
        fatal("can't open output file");
    }

    return fd;
}

ThreadContext *
Process::findFreeContext()
{
    for (int id : contextIds) {
        ThreadContext *tc = system->getThreadContext(id);
        if (tc->status() == ThreadContext::Halted)
            return tc;
    }
    return NULL;
}

void
Process::initState()
{
    if (contextIds.empty())
        fatal("Process %s is not associated with any HW contexts!\n", name());

    // first thread context for this process... initialize & enable
    ThreadContext *tc = system->getThreadContext(contextIds[0]);

    // mark this context as active so it will start ticking.
    tc->activate();

    pTable->initState(tc);
}

DrainState
Process::drain()
{
    find_file_offsets();
    return DrainState::Drained;
}

int
Process::alloc_fd(int sim_fd, const string& filename, int flags, int mode,
                  bool pipe)
{
    // in case open() returns an error, don't allocate a new fd
    if (sim_fd == -1)
        return -1;

    // find first free target fd
    for (int free_fd = 0; free_fd < NUM_FDS; ++free_fd) {
        Process::FdMap *fdo = &fd_map[free_fd];
        if (fdo->fd == -1 && fdo->driver == NULL) {
            fdo->fd = sim_fd;
            fdo->filename = filename;
            fdo->mode = mode;
            fdo->fileOffset = 0;
            fdo->flags = flags;
            fdo->isPipe = pipe;
            fdo->readPipeSource = 0;
            return free_fd;
        }
    }

    panic("Process::alloc_fd: out of file descriptors!");
}

void
Process::free_fdmap_entry(int tgt_fd)
{
    Process::FdMap *fdo = &fd_map[tgt_fd];
    assert(fd_map[tgt_fd].fd > -1);

    fdo->fd = -1;
    fdo->filename = "NULL";
    fdo->mode = 0;
    fdo->fileOffset = 0;
    fdo->flags = 0;
    fdo->isPipe = false;
    fdo->readPipeSource = 0;
    fdo->driver = NULL;
}

int
Process::sim_fd(int tgt_fd)
{
    FdMap *obj = sim_fd_obj(tgt_fd);
    return obj ? obj->fd : -1;
}

Process::FdMap *
Process::sim_fd_obj(int tgt_fd)
{
    if (tgt_fd < 0 || tgt_fd >= NUM_FDS)
        return NULL;
    return &fd_map[tgt_fd];
}

int
Process::tgt_fd(int sim_fd)
{
    for (int index = 0; index < NUM_FDS; ++index)
        if (fd_map[index].fd == sim_fd)
            return index;
    return -1;
}

void
Process::allocateMem(Addr vaddr, int64_t size, bool clobber)
{
    int npages = divCeil(size, (int64_t)PageBytes);
    Addr paddr = system->allocPhysPages(npages);
    pTable->map(vaddr, paddr, size, clobber ? PageTableBase::Clobber : 0);
}

bool
Process::fixupStackFault(Addr vaddr)
{
    // Check if this is already on the stack and there's just no page there
    // yet.
    if (vaddr >= stack_min && vaddr < stack_base) {
        allocateMem(roundDown(vaddr, PageBytes), PageBytes);
        return true;
    }

    // We've accessed the next page of the stack, so extend it to include
    // this address.
    if (vaddr < stack_min && vaddr >= stack_base - max_stack_size) {
        while (vaddr < stack_min) {
            stack_min -= TheISA::PageBytes;
            if (stack_base - stack_min > max_stack_size)
                fatal("Maximum stack size exceeded\n");
            allocateMem(stack_min, TheISA::PageBytes);
            inform("Increasing stack size by one page.");
        };
        return true;
    }
    return false;
}

// find all offsets for currently open files and save them
void
Process::fix_file_offsets()
{
    Process::FdMap *fdo_stdin = &fd_map[STDIN_FILENO];
    Process::FdMap *fdo_stdout = &fd_map[STDOUT_FILENO];
    Process::FdMap *fdo_stderr = &fd_map[STDERR_FILENO];
    string in = fdo_stdin->filename;
    string out = fdo_stdout->filename;
    string err = fdo_stderr->filename;

    // initialize file descriptors to default: same as simulator
    int stdin_fd, stdout_fd, stderr_fd;

    if (in == "stdin" || in == "cin")
        stdin_fd = STDIN_FILENO;
    else if (in == "NULL")
        stdin_fd = -1;
    else {
        // open standard in and seek to the right location
        stdin_fd = Process::openInputFile(in);
        if (lseek(stdin_fd, fdo_stdin->fileOffset, SEEK_SET) < 0)
            panic("Unable to seek to correct location in file: %s", in);
    }

    if (out == "stdout" || out == "cout")
        stdout_fd = STDOUT_FILENO;
    else if (out == "stderr" || out == "cerr")
        stdout_fd = STDERR_FILENO;
    else if (out == "NULL")
        stdout_fd = -1;
    else {
        stdout_fd = Process::openOutputFile(out);
        if (lseek(stdout_fd, fdo_stdout->fileOffset, SEEK_SET) < 0)
            panic("Unable to seek to correct location in file: %s", out);
    }

    if (err == "stdout" || err == "cout")
        stderr_fd = STDOUT_FILENO;
    else if (err == "stderr" || err == "cerr")
        stderr_fd = STDERR_FILENO;
    else if (err == "NULL")
        stderr_fd = -1;
    else if (err == out)
        stderr_fd = stdout_fd;
    else {
        stderr_fd = Process::openOutputFile(err);
        if (lseek(stderr_fd, fdo_stderr->fileOffset, SEEK_SET) < 0)
            panic("Unable to seek to correct location in file: %s", err);
    }

    fdo_stdin->fd = stdin_fd;
    fdo_stdout->fd = stdout_fd;
    fdo_stderr->fd = stderr_fd;


    for (int free_fd = 3; free_fd < NUM_FDS; ++free_fd) {
        Process::FdMap *fdo = &fd_map[free_fd];
        if (fdo->fd != -1) {
            if (fdo->isPipe){
                if (fdo->filename == "PIPE-WRITE")
                    continue;
                else {
                    assert (fdo->filename == "PIPE-READ");
                    //create a new pipe
                    int fds[2];
                    int pipe_retval = pipe(fds);

                    if (pipe_retval < 0) {
                        // error
                        panic("Unable to create new pipe.");
                    }
                    fdo->fd = fds[0]; //set read pipe
                    Process::FdMap *fdo_write = &fd_map[fdo->readPipeSource];
                    if (fdo_write->filename != "PIPE-WRITE")
                        panic ("Couldn't find write end of the pipe");

                    fdo_write->fd = fds[1];//set write pipe
               }
            } else {
                //Open file
                int fd = open(fdo->filename.c_str(), fdo->flags, fdo->mode);

                if (fd == -1)
                    panic("Unable to open file: %s", fdo->filename);
                fdo->fd = fd;

                //Seek to correct location before checkpoint
                if (lseek(fd, fdo->fileOffset, SEEK_SET) < 0)
                    panic("Unable to seek to correct location in file: %s",
                          fdo->filename);
            }
        }
    }
}

void
Process::find_file_offsets()
{
    for (int free_fd = 0; free_fd < NUM_FDS; ++free_fd) {
        Process::FdMap *fdo = &fd_map[free_fd];
        if (fdo->fd != -1) {
            fdo->fileOffset = lseek(fdo->fd, 0, SEEK_CUR);
        } else {
            fdo->filename = "NULL";
            fdo->fileOffset = 0;
        }
    }
}

void
Process::setReadPipeSource(int read_pipe_fd, int source_fd)
{
    Process::FdMap *fdo = &fd_map[read_pipe_fd];
    fdo->readPipeSource = source_fd;
}

void
Process::FdMap::serialize(CheckpointOut &cp) const
{
    SERIALIZE_SCALAR(fd);
    SERIALIZE_SCALAR(isPipe);
    SERIALIZE_SCALAR(filename);
    SERIALIZE_SCALAR(flags);
    SERIALIZE_SCALAR(readPipeSource);
    SERIALIZE_SCALAR(fileOffset);
}

void
Process::FdMap::unserialize(CheckpointIn &cp)
{
    UNSERIALIZE_SCALAR(fd);
    UNSERIALIZE_SCALAR(isPipe);
    UNSERIALIZE_SCALAR(filename);
    UNSERIALIZE_SCALAR(flags);
    UNSERIALIZE_SCALAR(readPipeSource);
    UNSERIALIZE_SCALAR(fileOffset);
}

void
Process::serialize(CheckpointOut &cp) const
{
    SERIALIZE_SCALAR(brk_point);
    SERIALIZE_SCALAR(stack_base);
    SERIALIZE_SCALAR(stack_size);
    SERIALIZE_SCALAR(stack_min);
    SERIALIZE_SCALAR(next_thread_stack_base);
    SERIALIZE_SCALAR(mmap_start);
    SERIALIZE_SCALAR(mmap_end);
    SERIALIZE_SCALAR(nxm_start);
    SERIALIZE_SCALAR(nxm_end);
    pTable->serialize(cp);
    for (int x = 0; x < NUM_FDS; x++) {
        fd_map[x].serializeSection(cp, csprintf("FdMap%d", x));
    }
    SERIALIZE_SCALAR(M5_pid);

}

void
Process::unserialize(CheckpointIn &cp)
{
    UNSERIALIZE_SCALAR(brk_point);
    UNSERIALIZE_SCALAR(stack_base);
    UNSERIALIZE_SCALAR(stack_size);
    UNSERIALIZE_SCALAR(stack_min);
    UNSERIALIZE_SCALAR(next_thread_stack_base);
    UNSERIALIZE_SCALAR(mmap_start);
    UNSERIALIZE_SCALAR(mmap_end);
    UNSERIALIZE_SCALAR(nxm_start);
    UNSERIALIZE_SCALAR(nxm_end);
    pTable->unserialize(cp);
    for (int x = 0; x < NUM_FDS; x++) {
        fd_map[x].unserializeSection(cp, csprintf("FdMap%d", x));
    }
    fix_file_offsets();
    UNSERIALIZE_OPT_SCALAR(M5_pid);
    // The above returns a bool so that you could do something if you don't
    // find the param in the checkpoint if you wanted to, like set a default
    // but in this case we'll just stick with the instantianted value if not
    // found.
}


bool
Process::map(Addr vaddr, Addr paddr, int size, bool cacheable)
{
    pTable->map(vaddr, paddr, size,
                cacheable ? 0 : PageTableBase::Uncacheable);
    return true;
}


////////////////////////////////////////////////////////////////////////
//
// LiveProcess member definitions
//
////////////////////////////////////////////////////////////////////////


LiveProcess::LiveProcess(LiveProcessParams *params, ObjectFile *_objFile)
    : Process(params), objFile(_objFile),
      argv(params->cmd), envp(params->env), cwd(params->cwd),
      __uid(params->uid), __euid(params->euid),
      __gid(params->gid), __egid(params->egid),
      __pid(params->pid), __ppid(params->ppid),
      drivers(params->drivers)
{

    // load up symbols, if any... these may be used for debugging or
    // profiling.
    if (!debugSymbolTable) {
        debugSymbolTable = new SymbolTable();
        if (!objFile->loadGlobalSymbols(debugSymbolTable) ||
            !objFile->loadLocalSymbols(debugSymbolTable) ||
            !objFile->loadWeakSymbols(debugSymbolTable)) {
            // didn't load any symbols
            delete debugSymbolTable;
            debugSymbolTable = NULL;
        }
    }
}

void
LiveProcess::syscall(int64_t callnum, ThreadContext *tc)
{
    num_syscalls++;

    SyscallDesc *desc = getDesc(callnum);
    if (desc == NULL)
        fatal("Syscall %d out of range", callnum);

    desc->doSyscall(callnum, this, tc);
}

IntReg
LiveProcess::getSyscallArg(ThreadContext *tc, int &i, int width)
{
    return getSyscallArg(tc, i);
}


EmulatedDriver *
LiveProcess::findDriver(std::string filename)
{
    for (EmulatedDriver *d : drivers) {
        if (d->match(filename))
            return d;
    }

    return NULL;
}


LiveProcess *
LiveProcess::create(LiveProcessParams * params)
{
    LiveProcess *process = NULL;

    string executable =
        params->executable == "" ? params->cmd[0] : params->executable;
    ObjectFile *objFile = createObjectFile(executable);
    if (objFile == NULL) {
        fatal("Can't load object file %s", executable);
    }

    if (objFile->isDynamic())
       fatal("Object file is a dynamic executable however only static "
             "executables are supported!\n       Please recompile your "
             "executable as a static binary and try again.\n");

#if THE_ISA == ALPHA_ISA
    if (objFile->getArch() != ObjectFile::Alpha)
        fatal("Object file architecture does not match compiled ISA (Alpha).");

    switch (objFile->getOpSys()) {
      case ObjectFile::Tru64:
        process = new AlphaTru64Process(params, objFile);
        break;

      case ObjectFile::UnknownOpSys:
        warn("Unknown operating system; assuming Linux.");
        // fall through
      case ObjectFile::Linux:
        process = new AlphaLinuxProcess(params, objFile);
        break;

      default:
        fatal("Unknown/unsupported operating system.");
    }
#elif THE_ISA == SPARC_ISA
    if (objFile->getArch() != ObjectFile::SPARC64 &&
        objFile->getArch() != ObjectFile::SPARC32)
        fatal("Object file architecture does not match compiled ISA (SPARC).");
    switch (objFile->getOpSys()) {
      case ObjectFile::UnknownOpSys:
        warn("Unknown operating system; assuming Linux.");
        // fall through
      case ObjectFile::Linux:
        if (objFile->getArch() == ObjectFile::SPARC64) {
            process = new Sparc64LinuxProcess(params, objFile);
        } else {
            process = new Sparc32LinuxProcess(params, objFile);
        }
        break;


      case ObjectFile::Solaris:
        process = new SparcSolarisProcess(params, objFile);
        break;

      default:
        fatal("Unknown/unsupported operating system.");
    }
#elif THE_ISA == X86_ISA
    if (objFile->getArch() != ObjectFile::X86_64 &&
        objFile->getArch() != ObjectFile::I386)
        fatal("Object file architecture does not match compiled ISA (x86).");
    switch (objFile->getOpSys()) {
      case ObjectFile::UnknownOpSys:
        warn("Unknown operating system; assuming Linux.");
        // fall through
      case ObjectFile::Linux:
        if (objFile->getArch() == ObjectFile::X86_64) {
            process = new X86_64LinuxProcess(params, objFile);
        } else {
            process = new I386LinuxProcess(params, objFile);
        }
        break;

      default:
        fatal("Unknown/unsupported operating system.");
    }
#elif THE_ISA == MIPS_ISA
    if (objFile->getArch() != ObjectFile::Mips)
        fatal("Object file architecture does not match compiled ISA (MIPS).");
    switch (objFile->getOpSys()) {
      case ObjectFile::UnknownOpSys:
        warn("Unknown operating system; assuming Linux.");
        // fall through
      case ObjectFile::Linux:
        process = new MipsLinuxProcess(params, objFile);
        break;

      default:
        fatal("Unknown/unsupported operating system.");
    }
#elif THE_ISA == ARM_ISA
    ObjectFile::Arch arch = objFile->getArch();
    if (arch != ObjectFile::Arm && arch != ObjectFile::Thumb &&
        arch != ObjectFile::Arm64)
        fatal("Object file architecture does not match compiled ISA (ARM).");
    switch (objFile->getOpSys()) {
      case ObjectFile::UnknownOpSys:
        warn("Unknown operating system; assuming Linux.");
        // fall through
      case ObjectFile::Linux:
        if (arch == ObjectFile::Arm64) {
            process = new ArmLinuxProcess64(params, objFile,
                                            objFile->getArch());
        } else {
            process = new ArmLinuxProcess32(params, objFile,
                                            objFile->getArch());
        }
        break;
      case ObjectFile::FreeBSD:
        if (arch == ObjectFile::Arm64) {
            process = new ArmFreebsdProcess64(params, objFile,
                                              objFile->getArch());
        } else {
            process = new ArmFreebsdProcess32(params, objFile,
                                              objFile->getArch());
        }
        break;
      case ObjectFile::LinuxArmOABI:
        fatal("M5 does not support ARM OABI binaries. Please recompile with an"
              " EABI compiler.");
      default:
        fatal("Unknown/unsupported operating system.");
    }
#elif THE_ISA == POWER_ISA
    if (objFile->getArch() != ObjectFile::Power)
        fatal("Object file architecture does not match compiled ISA (Power).");
    switch (objFile->getOpSys()) {
      case ObjectFile::UnknownOpSys:
        warn("Unknown operating system; assuming Linux.");
        // fall through
      case ObjectFile::Linux:
        process = new PowerLinuxProcess(params, objFile);
        break;

      default:
        fatal("Unknown/unsupported operating system.");
    }
#else
#error "THE_ISA not set"
#endif

    if (process == NULL)
        fatal("Unknown error creating process object.");
    return process;
}

LiveProcess *
LiveProcessParams::create()
{
    return LiveProcess::create(this);
}