// The contents of this file are subject to the BOINC Public License
// Version 1.0 (the "License"); you may not use this file except in
// compliance with the License. You may obtain a copy of the License at
// http://boinc.berkeley.edu/license_1.0.txt
// 
// Software distributed under the License is distributed on an "AS IS"
// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
// License for the specific language governing rights and limitations
// under the License. 
// 
// The Original Code is the Berkeley Open Infrastructure for Network Computing. 
// 
// The Initial Developer of the Original Code is the SETI@home project.
// Portions created by the SETI@home project are Copyright (C) 2002
// University of California at Berkeley. All Rights Reserved. 
// 
// Contributor(s):
//

// initialization and starting of applications

#include "cpp.h"

#ifdef _WIN32
#include "boinc_win.h"
#else
#if HAVE_SYS_IPC_H
#include <sys/ipc.h>
#endif
#if HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#if HAVE_SYS_WAIT_H
#include <sys/wait.h>
#endif
#include <unistd.h>
#include <cerrno>
#endif

using std::vector;

#include "filesys.h"
#include "error_numbers.h"
#include "util.h"
#include "shmem.h"
#include "client_msgs.h"
#include "client_state.h"
#include "file_names.h"

#include "app.h"

// ways an active task can be started by the client
//
#define TASK_RESUME     0   // process suspended; call unsuspend()
#define TASK_RESTART    1   // process initialized; call start(false)
#define TASK_START      2   // process uninitialized; call start(true)

// value for setpriority(2)
static const int PROCESS_IDLE_PRIORITY = 19;

// Goes through an array of strings, and prints each string
//
static int debug_print_argv(char** argv) {
    int i;

    log_messages.printf(CLIENT_MSG_LOG::DEBUG_TASK, "Arguments:");
    ++log_messages;
    for (i=0; argv[i]; i++) {
        log_messages.printf(
            CLIENT_MSG_LOG::DEBUG_TASK,
            "argv[%d]: %s\n", i, argv[i]
        );
    }
    --log_messages;

    return 0;
}

int ACTIVE_TASK::link_user_files() {
    PROJECT* project = wup->project;
    unsigned int i;
    FILE_REF fref;
    FILE_INFO* fip;
    char link_path[256], buf[256], file_path[256];
    int retval;

    for (i=0; i<project->user_files.size(); i++) {
        fref = project->user_files[i];
        fip = fref.file_info;
        if (fip->status != FILE_PRESENT) continue;
        get_pathname(fip, file_path);
        sprintf(link_path, "%s%s%s", slot_dir, PATH_SEPARATOR, strlen(fref.open_name)?fref.open_name:fip->name);
        sprintf(buf, "..%s..%s%s", PATH_SEPARATOR, PATH_SEPARATOR, file_path);
        retval = boinc_link(buf, link_path);
        if (retval) return retval;
    }
    return 0;
}

// write the app init file.
// This is done before starting the app,
// and when project prefs have changed during app execution
//
int ACTIVE_TASK::write_app_init_file(APP_INIT_DATA& aid) {
    FILE *f;
    char init_data_path[256], project_dir[256], project_path[256];
    int retval;

    memset(&aid, 0, sizeof(aid));

    aid.core_version = gstate.core_client_major_version*100 + gstate.core_client_minor_version;
    safe_strcpy(aid.app_name, wup->app->name);
    safe_strcpy(aid.user_name, wup->project->user_name);
    safe_strcpy(aid.team_name, wup->project->team_name);
    if (wup->project->project_specific_prefs.length()) {
        strcpy(aid.project_preferences, wup->project->project_specific_prefs.c_str());
    }
    get_project_dir(wup->project, project_dir);
    relative_to_absolute(project_dir, project_path);
    strcpy(aid.project_dir, project_path);
    relative_to_absolute("", aid.boinc_dir);
    strcpy(aid.authenticator, wup->project->authenticator);
    aid.slot = slot;
    strcpy(aid.wu_name, wup->name);
    aid.user_total_credit = wup->project->user_total_credit;
    aid.user_expavg_credit = wup->project->user_expavg_credit;
    aid.host_total_credit = wup->project->host_total_credit;
    aid.host_expavg_credit = wup->project->host_expavg_credit;
    aid.checkpoint_period = gstate.global_prefs.disk_interval;
    aid.fraction_done_update_period = DEFAULT_FRACTION_DONE_UPDATE_PERIOD;
    aid.fraction_done_start = 0;
    aid.fraction_done_end = 1;
#ifndef _WIN32
    aid.shm_key = 0;
#endif
    // wu_cpu_time is the CPU time at start of session,
    // not the checkpoint CPU time
    // At the start of an episode these are equal, but not in the middle!
    //
    aid.wu_cpu_time = episode_start_cpu_time;

    sprintf(init_data_path, "%s%s%s", slot_dir, PATH_SEPARATOR, INIT_DATA_FILE);
    f = boinc_fopen(init_data_path, "w");
    if (!f) {
        msg_printf(wup->project, MSG_ERROR,
            "Failed to open core-to-app prefs file %s",
            init_data_path
        );
        return ERR_FOPEN;
    }

    // make a unique key for core/app shared memory segment
    //
#ifdef _WIN32
    int     i = 0;
    char    szSharedMemoryName[256];
    HANDLE  hSharedMemoryHandle;

    do {
        memset(szSharedMemoryName, '\0', sizeof(szSharedMemoryName));
        sprintf(szSharedMemoryName, "boinc_%d", slot);
        i++;
    } while((!(hSharedMemoryHandle = create_shmem(szSharedMemoryName, 1024, NULL))) || (1024 < i));

    if (hSharedMemoryHandle)
        CloseHandle(hSharedMemoryHandle);

    if (1024 < i)
        return ERR_SEMOP;

    strcpy(aid.comm_obj_name, szSharedMemoryName);
#elif HAVE_SYS_IPC_H
    aid.shm_key = ftok(init_data_path, slot);
#else
#error shared memory key generation unimplemented
#endif

    aid.host_info = gstate.host_info;
    retval = write_init_data_file(f, aid);
    fclose(f);
    return retval;
}

// set up a 'symbolic link' in the slot dir to the given file
// (or copy the file to slot dir)
//
static int setup_file(
    WORKUNIT* wup, FILE_INFO* fip, FILE_REF& fref,
    char* file_path, char* slot_dir
) {
    char link_path[256], buf[256];
    int retval;

    sprintf(link_path,
        "%s%s%s", slot_dir, PATH_SEPARATOR,
        strlen(fref.open_name)?fref.open_name:fip->name
    );
    sprintf(buf, "..%s..%s%s", PATH_SEPARATOR, PATH_SEPARATOR, file_path );
    if (fref.copy_file) {
        retval = boinc_copy(file_path, link_path);
        if (retval) {
            msg_printf(wup->project, MSG_ERROR, "Can't copy %s to %s", file_path, link_path);
            return retval;
        }
    } else {
        retval = boinc_link(buf, link_path);
        if (retval) {
            msg_printf(wup->project, MSG_ERROR, "Can't link %s to %s", file_path, link_path);
            return retval;
        }
    }
    return 0;
}

// Start a task in a slot directory.
// This includes setting up soft links,
// passing preferences, and starting the process
//
// Current dir is top-level BOINC dir
//
int ACTIVE_TASK::start(bool first_time) {
    char exec_name[256], file_path[256], buf[256], exec_path[256];
    unsigned int i;
    FILE_REF fref;
    FILE_INFO* fip;
    int retval;
    char graphics_data_path[256];
    GRAPHICS_INFO gi;
    APP_INIT_DATA aid;

    SCOPE_MSG_LOG scope_messages(log_messages, CLIENT_MSG_LOG::DEBUG_TASK);
    scope_messages.printf("ACTIVE_TASK::start(first_time=%d)\n", first_time);

    if (first_time) {
        checkpoint_cpu_time = 0;
    }
    current_cpu_time = checkpoint_cpu_time;
    episode_start_cpu_time = checkpoint_cpu_time;
    cpu_time_at_last_sched = checkpoint_cpu_time;
    fraction_done = 0;

    gi.xsize = 800;
    gi.ysize = 600;
    gi.refresh_period = 0.1;

    retval = write_app_init_file(aid);
    if (retval) return retval;

    sprintf(graphics_data_path, "%s%s%s", slot_dir, PATH_SEPARATOR, GRAPHICS_DATA_FILE);
    FILE* gf = boinc_fopen(graphics_data_path, "w");
    if (!gf) {
        msg_printf(wup->project, MSG_ERROR,
            "Failed to open core-to-app graphics prefs file %s",
            graphics_data_path
        );
        return ERR_FOPEN;
    }
    retval = write_graphics_file(gf, &gi);
    fclose(gf);

    // set up applications files
    //
    for (i=0; i<app_version->app_files.size(); i++) {
        FILE_REF fref = app_version->app_files[i];
        fip = fref.file_info;
        get_pathname(fip, file_path);
        if (fref.main_program) {
            safe_strcpy(exec_name, fip->name);
            safe_strcpy(exec_path, file_path);
        }
        if (first_time) {
            retval = setup_file(wup, fip, fref, file_path, slot_dir);
            if (retval) return retval;
        }
    }

    // set up input files
    //
    for (i=0; i<wup->input_files.size(); i++) {
        fref = wup->input_files[i];
        fip = fref.file_info;
        get_pathname(fref.file_info, file_path);
        if (first_time) {
            retval = setup_file(wup, fip, fref, file_path, slot_dir);
            if (retval) return retval;
        }
    }

    // set up output files
    //
    for (i=0; i<result->output_files.size(); i++) {
        fref = result->output_files[i];
        fip = fref.file_info;
        get_pathname(fref.file_info, file_path);
        if (first_time) {
            retval = setup_file(wup, fip, fref, file_path, slot_dir);
            if (retval) return retval;
        }
    }

    link_user_files();

#ifdef _WIN32
    PROCESS_INFORMATION process_info;
    STARTUPINFO startup_info;
    char slotdirpath[256];
    char cmd_line[512];

    memset(&process_info, 0, sizeof(process_info));
    memset(&startup_info, 0, sizeof(startup_info));
    startup_info.cb = sizeof(startup_info);
    startup_info.lpReserved = NULL;
    startup_info.lpDesktop = "";

    sprintf(buf, "%s%s", QUIT_PREFIX, aid.comm_obj_name);
    quitRequestEvent = CreateEvent(0, FALSE, FALSE, buf);

    // create core/app share mem segment
    //
    sprintf(buf, "%s%s", SHM_PREFIX, aid.comm_obj_name);
    shm_handle = create_shmem(buf, sizeof(SHARED_MEM),
        (void **)&app_client_shm.shm
    );
    if (shm_handle == NULL) return ERR_SHMGET;
    app_client_shm.reset_msgs();

    // NOTE: in Windows, stderr is redirected within boinc_init();

    sprintf(cmd_line, "%s %s", exec_path, wup->command_line);
    relative_to_absolute(slot_dir, slotdirpath);
    if (!CreateProcess(exec_path,
        cmd_line,
        NULL,
        NULL,
        FALSE,
        CREATE_NEW_PROCESS_GROUP|CREATE_NO_WINDOW|IDLE_PRIORITY_CLASS,
        NULL,
        slotdirpath,
        &startup_info,
        &process_info
    )) {
        char szError[1024];
        windows_error_string(szError, sizeof(szError));

        state = PROCESS_COULDNT_START;
        result->active_task_state = PROCESS_COULDNT_START;
        gstate.report_result_error(*result, ERR_EXEC, "CreateProcess() failed - %s", szError);
        msg_printf(wup->project, MSG_ERROR, "CreateProcess() failed - %s", szError);
        return ERR_EXEC;
    }
    pid = process_info.dwProcessId;
    pid_handle = process_info.hProcess;
    thread_handle = process_info.hThread;
#else
    char* argv[100];

    // Set up core/app shared memory seg
    //
    shm_key = aid.shm_key;
    retval = create_shmem(
        shm_key, sizeof(SHARED_MEM), (void**)&app_client_shm.shm
    );
    if (retval) {
        msg_printf(
            wup->project, MSG_ERROR, "Can't create shared mem: %d", retval
        );
        return retval;
    }
    app_client_shm.reset_msgs();

    pid = fork();
    if (pid == -1) {
        state = PROCESS_COULDNT_START;
        result->active_task_state = PROCESS_COULDNT_START;
        gstate.report_result_error(*result, -1, "fork(): %s", strerror(errno));
        msg_printf(wup->project, MSG_ERROR, "fork(): %s", strerror(errno));
        return ERR_FORK;
    }
    if (pid == 0) {
        // from here on we're running in a new process.
        // If an error happens, exit nonzero so that the core client
        // knows there was a problem.

        // chdir() into the slot directory
        //
        retval = chdir(slot_dir);
        if (retval) {
            perror("chdir");
            _exit(retval);
        }

        // hook up stderr to a specially-named file
        //
        freopen(STDERR_FILE, "a", stderr);

        argv[0] = exec_name;
        parse_command_line(wup->command_line, argv+1);
        debug_print_argv(argv);
        sprintf(buf, "..%s..%s%s", PATH_SEPARATOR, PATH_SEPARATOR, exec_path );
        retval = execv(buf, argv);
        msg_printf(wup->project, MSG_ERROR,
            "execv(%s) failed: %d\n", buf, retval
        );
        perror("execv");
        _exit(errno);
    }

    scope_messages.printf("ACTIVE_TASK::start(): forked process: pid %d\n", pid);

    // set idle process priority
#ifdef HAVE_SETPRIORITY
    if (setpriority(PRIO_PROCESS, pid, PROCESS_IDLE_PRIORITY)) {
        perror("setpriority");
    }
#endif

#endif
    state = PROCESS_RUNNING;
    result->active_task_state = PROCESS_RUNNING;
    scheduler_state = CPU_SCHED_RUNNING;
    return 0;
}

// Resume the task if it was previously running
// Otherwise, start it
//
int ACTIVE_TASK::resume_or_start() {
    static const char process_start_types[3][15] = {
        "Resuming",
        "Restarting",
        "Starting"
    };
    int retval;
    int task_start_type;

    if (state == PROCESS_RUNNING) {
#if _WIN32
        unsigned long exit_code;
        GetExitCodeProcess(pid_handle, &exit_code);
        if (exit_code != STILL_ACTIVE) {
            handle_exited_app(exit_code);
        }
#else
        int exited_pid;
        int stat;
        struct rusage rs;

        if ((exited_pid = wait4(0, &stat, WNOHANG, &rs)) == pid) {
            handle_exited_app(stat, rs);
        }
#endif
    }
    if (state == PROCESS_UNINITIALIZED) {
        if (scheduler_state == CPU_SCHED_UNINITIALIZED) {
            if (!boinc_file_exists(slot_dir)) {
                make_slot_dir(slot);
            }
            retval = clean_out_dir(slot_dir);
            retval = start(true);
            task_start_type = TASK_START;
        } else {
            retval = start(false);
            task_start_type = TASK_RESTART;
        }
        if (retval) return retval;
    } else {
        retval = unsuspend();
        if (retval) {
            msg_printf(
                wup->project,
                MSG_ERROR,
                "ACTIVE_TASK::resume_or_start(): could not unsuspend active_task"
            );
            return retval;
        }
        scheduler_state = CPU_SCHED_RUNNING;
        task_start_type = TASK_RESUME;
    }
    msg_printf(result->project, MSG_INFO,
        "%s computation for result %s using %s version %.2f",
        process_start_types[task_start_type],
        result->name,
        app_version->app->name,
        app_version->version_num/100.
    );
    return 0;
}

// Restart active tasks without wiping and reinitializing slot directories
// Called at init, with max_tasks = ncpus
//
int ACTIVE_TASK_SET::restart_tasks(int max_tasks) {
    vector<ACTIVE_TASK*>::iterator iter;
    ACTIVE_TASK* atp;
    RESULT* result;
    int retval, num_tasks_started;

    SCOPE_MSG_LOG scope_messages(log_messages, CLIENT_MSG_LOG::DEBUG_TASK);

    num_tasks_started = 0;
    iter = active_tasks.begin();
    while (iter != active_tasks.end()) {
        atp = *iter;
        result = atp->result;
        atp->init(atp->result);
        get_slot_dir(atp->slot, atp->slot_dir);
        if (!gstate.input_files_available(result)) {
            msg_printf(atp->wup->project, MSG_ERROR, "ACTIVE_TASKS::restart_tasks(); missing files\n");
            atp->result->active_task_state = PROCESS_COULDNT_START;
            gstate.report_result_error(
                *(atp->result), ERR_FILE_MISSING,
                "One or more missing files"
            );
            iter = active_tasks.erase(iter);
            delete atp;
            continue;
        }

        if (atp->scheduler_state != CPU_SCHED_RUNNING
            || num_tasks_started >= max_tasks
        ) {
            msg_printf(atp->wup->project, MSG_INFO,
                "Deferring computation for result %s",
                atp->result->name
            );

            atp->scheduler_state = CPU_SCHED_PREEMPTED;
            iter++;
            continue;
        }

        result->is_active = true;

        msg_printf(atp->wup->project, MSG_INFO,
            "Resuming computation for result %s using %s version %.2f",
            atp->result->name,
            atp->app_version->app->name,
            atp->app_version->version_num/100.
        );
        retval = atp->start(false);

        if (retval) {
            msg_printf(atp->wup->project, MSG_ERROR, "ACTIVE_TASKS::restart_tasks(); restart failed: %d\n", retval);
            atp->result->active_task_state = PROCESS_COULDNT_START;
            gstate.report_result_error(
                *(atp->result), retval,
                "Couldn't restart the app for this result: %d", retval
            );
            iter = active_tasks.erase(iter);
            delete atp;
        } else {
            ++num_tasks_started;
            iter++;
        }
    }
    return 0;
}