/*
 * 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.
 */

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

#include <cstdio>
#include <string>

#include "base/intmath.hh"
#include "base/loader/object_file.hh"
#include "base/loader/symtab.hh"
#include "base/statistics.hh"
#include "config/full_system.hh"
#include "cpu/exec_context.hh"
#include "cpu/smt.hh"
#include "encumbered/cpu/full/thread.hh"
#include "encumbered/eio/eio.hh"
#include "encumbered/mem/functional/main.hh"
#include "sim/builder.hh"
#include "sim/fake_syscall.hh"
#include "sim/process.hh"
#include "sim/stats.hh"
#include "sim/syscall_emul.hh"

#include "arch/alpha_tru64_process.hh"
#include "arch/alpha_linux_process.hh"

using namespace std;
using namespace TheISA;

//
// The purpose of this code is to fake the loader & syscall mechanism
// when there's no OS: thus there's no resone to use it in FULL_SYSTEM
// mode when we do have an OS
//
#if FULL_SYSTEM
#error "process.cc not compatible with FULL_SYSTEM"
#endif

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

Process::Process(const string &nm,
                 int stdin_fd, 	// initial I/O descriptors
                 int stdout_fd,
                 int stderr_fd)
    : SimObject(nm)
{
    // allocate memory space
    memory = new MainMemory(nm + ".MainMem");

    // allocate initial register file
    init_regs = new RegFile;
    memset(init_regs, 0, sizeof(RegFile));

    // initialize first 3 fds (stdin, stdout, stderr)
    fd_map[STDIN_FILENO] = stdin_fd;
    fd_map[STDOUT_FILENO] = stdout_fd;
    fd_map[STDERR_FILENO] = stderr_fd;

    // mark remaining fds as free
    for (int i = 3; i <= MAX_FD; ++i) {
        fd_map[i] = -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() + ".PROG: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, 0774);

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

    return fd;
}


int
Process::registerExecContext(ExecContext *xc)
{
    // add to list
    int myIndex = execContexts.size();
    execContexts.push_back(xc);

    if (myIndex == 0) {
        // copy process's initial regs struct
        xc->regs = *init_regs;
    }

    // return CPU number to caller and increment available CPU count
    return myIndex;
}

void
Process::startup()
{
    if (execContexts.empty())
        return;

    // first exec context for this process... initialize & enable
    ExecContext *xc = execContexts[0];

    // mark this context as active so it will start ticking.
    xc->activate(0);
}

void
Process::replaceExecContext(ExecContext *xc, int xcIndex)
{
    if (xcIndex >= execContexts.size()) {
        panic("replaceExecContext: bad xcIndex, %d >= %d\n",
              xcIndex, execContexts.size());
    }

    execContexts[xcIndex] = xc;
}

// map simulator fd sim_fd to target fd tgt_fd
void
Process::dup_fd(int sim_fd, int tgt_fd)
{
    if (tgt_fd < 0 || tgt_fd > MAX_FD)
        panic("Process::dup_fd tried to dup past MAX_FD (%d)", tgt_fd);

    fd_map[tgt_fd] = sim_fd;
}


// generate new target fd for sim_fd
int
Process::alloc_fd(int sim_fd)
{
    // 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 < MAX_FD; ++free_fd) {
        if (fd_map[free_fd] == -1) {
            fd_map[free_fd] = sim_fd;
            return free_fd;
        }
    }

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


// free target fd (e.g., after close)
void
Process::free_fd(int tgt_fd)
{
    if (fd_map[tgt_fd] == -1)
        warn("Process::free_fd: request to free unused fd %d", tgt_fd);

    fd_map[tgt_fd] = -1;
}


// look up simulator fd for given target fd
int
Process::sim_fd(int tgt_fd)
{
    if (tgt_fd > MAX_FD)
        return -1;

    return fd_map[tgt_fd];
}



//
// need to declare these here since there is no concrete Process type
// that can be constructed (i.e., no REGISTER_SIM_OBJECT() macro call,
// which is where these get declared for concrete types).
//
DEFINE_SIM_OBJECT_CLASS_NAME("Process", Process)


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


static void
copyStringArray(vector<string> &strings, Addr array_ptr, Addr data_ptr,
                FunctionalMemory *memory)
{
    Addr data_ptr_swap;
    for (int i = 0; i < strings.size(); ++i) {
        data_ptr_swap = htog(data_ptr);
        memory->access(Write, array_ptr, &data_ptr_swap, sizeof(Addr));
        memory->writeString(data_ptr, strings[i].c_str());
        array_ptr += sizeof(Addr);
        data_ptr += strings[i].size() + 1;
    }
    // add NULL terminator
    data_ptr = 0;
    memory->access(Write, array_ptr, &data_ptr, sizeof(Addr));
}

LiveProcess::LiveProcess(const string &nm, ObjectFile *objFile,
                         int stdin_fd, int stdout_fd, int stderr_fd,
                         vector<string> &argv, vector<string> &envp)
    : Process(nm, stdin_fd, stdout_fd, stderr_fd)
{
    prog_fname = argv[0];

    prog_entry = objFile->entryPoint();
    text_base = objFile->textBase();
    text_size = objFile->textSize();
    data_base = objFile->dataBase();
    data_size = objFile->dataSize() + objFile->bssSize();
    brk_point = roundUp(data_base + data_size, VMPageSize);

    // load object file into target memory
    objFile->loadSections(memory);

    // 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)) {
            // didn't load any symbols
            delete debugSymbolTable;
            debugSymbolTable = NULL;
        }
    }

    // Set up stack.  On Alpha, stack goes below text section.  This
    // code should get moved to some architecture-specific spot.
    stack_base = text_base - (409600+4096);

    // Set up region for mmaps.  Tru64 seems to start just above 0 and
    // grow up from there.
    mmap_start = mmap_end = 0x10000;

    // Set pointer for next thread stack.  Reserve 8M for main stack.
    next_thread_stack_base = stack_base - (8 * 1024 * 1024);

    // Calculate how much space we need for arg & env arrays.
    int argv_array_size = sizeof(Addr) * (argv.size() + 1);
    int envp_array_size = sizeof(Addr) * (envp.size() + 1);
    int arg_data_size = 0;
    for (int i = 0; i < argv.size(); ++i) {
        arg_data_size += argv[i].size() + 1;
    }
    int env_data_size = 0;
    for (int i = 0; i < envp.size(); ++i) {
        env_data_size += envp[i].size() + 1;
    }

    int space_needed =
        argv_array_size + envp_array_size + arg_data_size + env_data_size;
    // for SimpleScalar compatibility
    if (space_needed < 16384)
        space_needed = 16384;

    // set bottom of stack
    stack_min = stack_base - space_needed;
    // align it
    stack_min &= ~7;
    stack_size = stack_base - stack_min;

    // map out initial stack contents
    Addr argv_array_base = stack_min + sizeof(uint64_t); // room for argc
    Addr envp_array_base = argv_array_base + argv_array_size;
    Addr arg_data_base = envp_array_base + envp_array_size;
    Addr env_data_base = arg_data_base + arg_data_size;

    // write contents to stack
    uint64_t argc = argv.size();
    argc = htog(argc);
    memory->access(Write, stack_min, &argc, sizeof(uint64_t));

    copyStringArray(argv, argv_array_base, arg_data_base, memory);
    copyStringArray(envp, envp_array_base, env_data_base, memory);

    init_regs->intRegFile[ArgumentReg0] = argc;
    init_regs->intRegFile[ArgumentReg1] = argv_array_base;
    init_regs->intRegFile[StackPointerReg] = stack_min;
    init_regs->intRegFile[GlobalPointerReg] = objFile->globalPointer();
    init_regs->pc = prog_entry;
    init_regs->npc = prog_entry + sizeof(MachInst);
}

void
LiveProcess::syscall(ExecContext *xc)
{
    num_syscalls++;

    int64_t callnum = xc->regs.intRegFile[ReturnValueReg];

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

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

LiveProcess *
LiveProcess::create(const string &nm,
                    int stdin_fd, int stdout_fd, int stderr_fd,
                    string executable,
                    vector<string> &argv, vector<string> &envp)
{
    LiveProcess *process = NULL;
    ObjectFile *objFile = createObjectFile(executable);
    if (objFile == NULL) {
        fatal("Can't load object file %s", executable);
    }

    // check object type & set up syscall emulation pointer
    if (objFile->getArch() == ObjectFile::Alpha) {
        switch (objFile->getOpSys()) {
          case ObjectFile::Tru64:
            process = new AlphaTru64Process(nm, objFile,
                                            stdin_fd, stdout_fd, stderr_fd,
                                            argv, envp);
            break;

          case ObjectFile::Linux:
            process = new AlphaLinuxProcess(nm, objFile,
                                            stdin_fd, stdout_fd, stderr_fd,
                                            argv, envp);
            break;

          default:
            fatal("Unknown/unsupported operating system.");
        }
    } else {
        fatal("Unknown object file architecture.");
    }

    delete objFile;

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

    return process;
}



BEGIN_DECLARE_SIM_OBJECT_PARAMS(LiveProcess)

    VectorParam<string> cmd;
    Param<string> executable;
    Param<string> input;
    Param<string> output;
    VectorParam<string> env;

END_DECLARE_SIM_OBJECT_PARAMS(LiveProcess)


BEGIN_INIT_SIM_OBJECT_PARAMS(LiveProcess)

    INIT_PARAM(cmd, "command line (executable plus arguments)"),
    INIT_PARAM(executable, "executable (overrides cmd[0] if set)"),
    INIT_PARAM(input, "filename for stdin (dflt: use sim stdin)"),
    INIT_PARAM(output, "filename for stdout/stderr (dflt: use sim stdout)"),
    INIT_PARAM(env, "environment settings")

END_INIT_SIM_OBJECT_PARAMS(LiveProcess)


CREATE_SIM_OBJECT(LiveProcess)
{
    string in = input;
    string out = output;

    // 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
        stdin_fd = Process::openInputFile(input);

    if (out == "stdout" || out == "cout")
        stdout_fd = STDOUT_FILENO;
    else if (out == "stderr" || out == "cerr")
        stdout_fd = STDERR_FILENO;
    else
        stdout_fd = Process::openOutputFile(out);

    stderr_fd = (stdout_fd != STDOUT_FILENO) ? stdout_fd : STDERR_FILENO;

    return LiveProcess::create(getInstanceName(),
                               stdin_fd, stdout_fd, stderr_fd,
                               (string)executable == "" ? cmd[0] : executable,
                               cmd, env);
}

REGISTER_SIM_OBJECT("LiveProcess", LiveProcess)