/*

 * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include "PosixPlatform.h"

#ifdef POSIX

#include "PlatformString.h"

#include "FilePath.h"

#include "Helpers.h"

#include <assert.h>

#include <stdbool.h>

#include <sys/types.h>

#include <unistd.h>

#include <sys/sysctl.h>

#include <sys/file.h>

#include <sys/stat.h>

#ifdef LINUX

#include <sys/wait.h>

#endif

#include <errno.h>

#include <limits.h>

#include <pwd.h>

#include <iostream>

#include <algorithm>

#include <dlfcn.h>

#include <signal.h>

PosixPlatform::PosixPlatform(void) {

}

PosixPlatform::~PosixPlatform(void) {

    if (!SingleInstanceFile.empty()) {

        unlink(SingleInstanceFile.c_str());

    }

}

TString PosixPlatform::GetTempDirectory() {

    struct passwd* pw = getpwuid(getuid());

    TString homedir(pw->pw_dir);

    homedir += getTmpDirString();

    if (!FilePath::DirectoryExists(homedir)) {

        if (!FilePath::CreateDirectory(homedir, false)) {

            homedir.clear();

        }

    }

    return homedir;

}

TString PosixPlatform::fixName(const TString& name) {

    TString fixedName(name);

    const TString chars("?:*<>/\\");

    for (TString::const_iterator it = chars.begin(); it != chars.end(); it++) {

        fixedName.erase(std::remove(fixedName.begin(),

                fixedName.end(), *it), fixedName.end());

    }

    return fixedName;

}

// returns true if another instance is already running.

// if false, we need to continue regular launch.

bool PosixPlatform::CheckForSingleInstance(TString appName) {

    TString tmpDir = GetTempDirectory();

    if (tmpDir.empty()) {

        printf("Unable to check for single instance.\n");

        return false;

    }

    TString lockFile = tmpDir + "/" + fixName(appName);

    SingleInstanceFile = lockFile;

    int pid_file = open(lockFile.c_str(), O_CREAT | O_RDWR, 0666);

    int rc = flock(pid_file, LOCK_EX | LOCK_NB);

    if (rc) {

        if (EWOULDBLOCK == errno) {

            // another instance is running

            pid_t pid = 0;

            read(pid_file, (void*)&pid, sizeof(pid_t));

            printf("Another instance is running PID: %d\n", pid);

            if (pid != 0) {

                singleInstanceProcessId = pid;

                SingleInstanceFile.clear();

                return true;

            }

        } else {

            printf("Unable to check for single instance.\n");

        }

    } else {

        // It is the first instance.

        pid_t pid = getpid();

        write(pid_file, (void*)&pid, sizeof(pid_t));

    }

    return false;

}

MessageResponse PosixPlatform::ShowResponseMessage(TString title,

        TString description) {

    MessageResponse result = mrCancel;

    printf("%s %s (Y/N)\n", PlatformString(title).toPlatformString(),

            PlatformString(description).toPlatformString());

    fflush(stdout);

    std::string input;

    std::cin >> input;

    if (input == "Y") {

        result = mrOK;

    }

    return result;

}

void PosixPlatform::SetCurrentDirectory(TString Value) {

    chdir(StringToFileSystemString(Value));

}

Module PosixPlatform::LoadLibrary(TString FileName) {

    return dlopen(StringToFileSystemString(FileName), RTLD_LAZY);

}

void PosixPlatform::FreeLibrary(Module AModule) {

    dlclose(AModule);

}

Procedure PosixPlatform::GetProcAddress(Module AModule,

        std::string MethodName) {

    return dlsym(AModule, PlatformString(MethodName));

}

std::vector<std::string> PosixPlatform::GetLibraryImports(

       const TString FileName) {

 std::vector<TString> result;

 return result;

}

std::vector<TString> PosixPlatform::FilterOutRuntimeDependenciesForPlatform(

       std::vector<TString> Imports) {

 std::vector<TString> result;

 return result;

}

Process* PosixPlatform::CreateProcess() {

    return new PosixProcess();

}

PosixProcess::PosixProcess() : Process() {

    FChildPID = 0;

    FRunning = false;

    FOutputHandle = 0;

    FInputHandle = 0;

}

PosixProcess::~PosixProcess() {

    Terminate();

}

void PosixProcess::Cleanup() {

    if (FOutputHandle != 0) {

        close(FOutputHandle);

        FOutputHandle = 0;

    }

    if (FInputHandle != 0) {

        close(FInputHandle);

        FInputHandle = 0;

    }

#ifdef MAC

    sigaction(SIGINT, &savintr, (struct sigaction *)0);

    sigaction(SIGQUIT, &savequit, (struct sigaction *)0);

    sigprocmask(SIG_SETMASK, &saveblock, (sigset_t *)0);

#endif //MAC

}

bool PosixProcess::ReadOutput() {

    bool result = false;

    if (FOutputHandle != 0 && IsRunning() == true) {

        char buffer[4096] = {0};

        ssize_t count = read(FOutputHandle, buffer, sizeof(buffer));

        if (count == -1) {

            if (errno == EINTR) {

                // continue;

            } else {

                perror("read");

                exit(1);

            }

        } else if (count == 0) {

            // break;

        } else {

            if (buffer[count - 1] == EOF) {

                buffer[count - 1] = '\0';

            }

            std::list<TString> output = Helpers::StringToArray(buffer);

            FOutput.splice(FOutput.end(), output, output.begin(), output.end());

            result = true;

        }

    }

    return false;

}

bool PosixProcess::IsRunning() {

    bool result = false;

    if (kill(FChildPID, 0) == 0) {

        result = true;

    }

    return result;

}

bool PosixProcess::Terminate() {

    bool result = false;

    if (IsRunning() == true && FRunning == true) {

        FRunning = false;

        Cleanup();

        int status = kill(FChildPID, SIGTERM);

        if (status == 0) {

            result = true;

        } else {

#ifdef DEBUG

            if (errno == EINVAL) {

                printf("Kill error: The value of the sig argument is an invalid or unsupported signal number.");

            } else if (errno == EPERM) {

                printf("Kill error: The process does not have permission to send the signal to any receiving process.");

            } else if (errno == ESRCH) {

                printf("Kill error: No process or process group can be found corresponding to that specified by pid.");

            }

#endif // DEBUG

            if (IsRunning() == true) {

                status = kill(FChildPID, SIGKILL);

                if (status == 0) {

                    result = true;

                }

            }

        }

    }

    return result;

}

#define PIPE_READ 0

#define PIPE_WRITE 1

bool PosixProcess::Execute(const TString Application,

        const std::vector<TString> Arguments, bool AWait) {

    bool result = false;

    if (FRunning == false) {

        FRunning = true;

        int handles[2];

        if (pipe(handles) == -1) {

            return false;

        }

        struct sigaction sa;

        sa.sa_handler = SIG_IGN;

        sigemptyset(&sa.sa_mask);

        sa.sa_flags = 0;

#ifdef MAC

        sigemptyset(&savintr.sa_mask);

        sigemptyset(&savequit.sa_mask);

        sigaction(SIGINT, &sa, &savintr);

        sigaction(SIGQUIT, &sa, &savequit);

        sigaddset(&sa.sa_mask, SIGCHLD);

        sigprocmask(SIG_BLOCK, &sa.sa_mask, &saveblock);

#endif // MAC

        FChildPID = fork();

        // PID returned by vfork is 0 for the child process and the

        // PID of the child process for the parent.

        if (FChildPID == -1) {

            // Error

            TString message = PlatformString::Format(

                    _T("Error: Unable to create process %s"),

                    Application.data());

            throw Exception(message);

        }

        else if (FChildPID == 0) {

            Cleanup();

            TString command = Application;

            for (std::vector<TString>::const_iterator iterator =

                    Arguments.begin(); iterator != Arguments.end();

                    iterator++) {

                command += TString(_T(" ")) + *iterator;

            }

#ifdef DEBUG

            printf("%s\n", command.data());

#endif // DEBUG

            dup2(handles[PIPE_READ], STDIN_FILENO);

            dup2(handles[PIPE_WRITE], STDOUT_FILENO);

            close(handles[PIPE_READ]);

            close(handles[PIPE_WRITE]);

            execl("/bin/sh", "sh", "-c", command.data(), (char *)0);

            _exit(127);

        } else {

            FOutputHandle = handles[PIPE_READ];

            FInputHandle = handles[PIPE_WRITE];

            if (AWait == true) {

                ReadOutput();

                Wait();

                Cleanup();

                FRunning = false;

                result = true;

            }

            else {

                result = true;

            }

        }

    }

    return result;

}

bool PosixProcess::Wait() {

    bool result = false;

    int status = 0;

    pid_t wpid = 0;

#ifdef LINUX

    wpid = wait(&status);

#endif

#ifdef MAC

    wpid = wait(&status);

#endif

    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {

        if (errno != EINTR){

            status = -1;

        }

    }

#ifdef DEBUG

    if (WIFEXITED(status)) {

        printf("child exited, status=%d\n", WEXITSTATUS(status));

    } else if (WIFSIGNALED(status)) {

        printf("child killed (signal %d)\n", WTERMSIG(status));

    } else if (WIFSTOPPED(status)) {

        printf("child stopped (signal %d)\n", WSTOPSIG(status));

#ifdef WIFCONTINUED // Not all implementations support this

    } else if (WIFCONTINUED(status)) {

        printf("child continued\n");

#endif // WIFCONTINUED

    } else { // Non-standard case -- may never happen

        printf("Unexpected status (0x%x)\n", status);

    }

#endif // DEBUG

    if (wpid != -1) {

        result = true;

    }

    return result;

}

TProcessID PosixProcess::GetProcessID() {

    return FChildPID;

}

void PosixProcess::SetInput(TString Value) {

    if (FInputHandle != 0) {

        write(FInputHandle, Value.data(), Value.size());

    }

}

std::list<TString> PosixProcess::GetOutput() {

    ReadOutput();

    return Process::GetOutput();

}

#endif // POSIX