boinc/api/boinc_api.C

// Berkeley Open Infrastructure for Network Computing
// http://boinc.berkeley.edu
// Copyright (C) 2005 University of California
//
// This is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation;
// either version 2.1 of the License, or (at your option) any later version.
//
// This software 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 Lesser General Public License for more details.
//
// To view the GNU Lesser General Public License visit
// http://www.gnu.org/copyleft/lesser.html
// or write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

#if defined(_WIN32) && !defined(__STDWX_H__) && !defined(_BOINC_WIN_) && !defined(_AFX_STDAFX_H_)
#include "boinc_win.h"
#endif

#ifdef _WIN32
#include "version.h"
#else
#include "config.h"
#include <cstdlib>
#include <cstdio>
#include <cstdarg>
#include <sys/types.h>
#include <errno.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <pthread.h>
#ifndef __EMX__
#include <sched.h>
#endif
using namespace std;
#endif

#include "diagnostics.h"
#include "parse.h"
#include "shmem.h"
#include "util.h"
#include "str_util.h"
#include "filesys.h"
#include "mem_usage.h"
#include "error_numbers.h"
#include "common_defs.h"
#include "app_ipc.h"

#include "boinc_api.h"

#ifdef __APPLE__
#include "mac_backtrace.h"
#define GETRUSAGE_IN_TIMER_THREAD
    // call getrusage() in the timer thread,
    // rather than in the worker thread's signal handler
    // (which can cause crashes on Mac)
    // If you want, you can set this for Linux too:
    // CPPFLAGS=-DGETRUSAGE_IN_TIMER_THREAD
#endif

// Implementation notes:
// 1) Thread structure, Unix:
//  getting CPU time and suspend/resume have to be done
//  in the worker thread, so we use a SIGALRM signal handler.
//  However, many library functions and system calls
//  are not "asynch signal safe": see, e.g.
//  http://www.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html#tag_02_04_03
//  (e.g. sprintf() in a signal handler hangs Mac OS X)
//  so we do as little as possible in the signal handler,
//  and do the rest in a separate "timer thread".
// 2) All variables that are accessed by two threads (i.e. worker and timer)
//  MUST be declared volatile.
// 3) For compatibility with C, we use int instead of bool various places

// Terminology:
// The processing of a result can be divided
// into multiple "episodes" (executions of the app),
// each of which resumes from the checkpointed state of the previous episode.
// Unless otherwise noted, "CPU time" refers to the sum over all episodes
// (not counting the part after the last checkpoint in an episode).

const char* api_version="API_VERSION_"PACKAGE_VERSION;
static APP_INIT_DATA aid;
static FILE_LOCK file_lock;
APP_CLIENT_SHM* app_client_shm = 0;
static volatile int time_until_checkpoint;
    // time until enable checkpoint
static volatile int time_until_fraction_done_update;
    // time until report fraction done to core client
static volatile double fraction_done;
static volatile double last_checkpoint_cpu_time;
static volatile bool ready_to_checkpoint = false;
static volatile int in_critical_section=0;
static volatile double last_wu_cpu_time;
static volatile bool standalone          = false;
static volatile double initial_wu_cpu_time;
static volatile bool have_new_trickle_up = false;
static volatile bool have_trickle_down = true;
    // on first call, scan slot dir for msgs
static volatile int heartbeat_giveup_time;
    // interrupt count value at which to give up on core client
#ifdef _WIN32
static volatile int nrunning_ticks = 0;
#endif
static volatile int interrupt_count = 0;
    // number of timer interrupts
    // used to measure elapsed time in a way that's
    // not affected by user changing system clock,
    // and doesn't have big jump after hibernation
static double fpops_per_cpu_sec = 0;
static double fpops_cumulative = 0;
static double intops_per_cpu_sec = 0;
static double intops_cumulative = 0;
static int want_network = 0;
static int have_network = 1;
static int ncpus_available;
static int nthreads;
bool g_sleep = false;
    // simulate unresponsive app by setting to true (debugging)
static FUNC_PTR timer_callback = 0;

#define TIMER_PERIOD 0.1
    // period of worker-thread timer interrupts.
    // Determines rate of handlling messages from client.
#define TIMERS_PER_SEC 10
    // This determines the resolution of fraction done and CPU time reporting
    // to the core client, and of checkpoint enabling.
    // It doesn't influence graphics, so 1 sec is enough.
#define HEARTBEAT_GIVEUP_COUNT ((int)(30/TIMER_PERIOD))
    // quit if no heartbeat from core in this #interrupts
#define LOCKFILE_TIMEOUT_PERIOD 35
    // quit if we cannot aquire slot lock file in this #secs after startup

#ifdef _WIN32
static HANDLE hSharedMem;
HANDLE worker_thread_handle;
    // used to suspend worker thread, and to measure its CPU time
#else
static volatile bool worker_thread_exit_flag = false;
static volatile int worker_thread_exit_status;
    // the above are used by the timer thread to tell
    // the worker thread to exit
static pthread_t timer_thread_handle;
#ifndef GETRUSAGE_IN_TIMER_THREAD
static struct rusage worker_thread_ru;
#endif
#endif

static BOINC_OPTIONS options;
static volatile BOINC_STATUS boinc_status;

// vars related to intermediate file upload
struct UPLOAD_FILE_STATUS {
    std::string name;
    int status;
};
static bool have_new_upload_file;
static std::vector<UPLOAD_FILE_STATUS> upload_file_status;

static void graphics_cleanup();
//static int suspend_activities();
//static int resume_activities();
//static void boinc_exit(int);
static void block_sigalrm();
static int start_worker_signals();

static int setup_shared_mem() {
    if (standalone) {
        fprintf(stderr, "Standalone mode, so not using shared memory.\n");
        return 0;
    }
    app_client_shm = new APP_CLIENT_SHM;

#ifdef _WIN32
    char buf[256];
    sprintf(buf, "%s%s", SHM_PREFIX, aid.shmem_seg_name);
    hSharedMem = attach_shmem(buf, (void**)&app_client_shm->shm);
    if (hSharedMem == NULL) {
        delete app_client_shm;
        app_client_shm = NULL;
    }
#else
    if (aid.shmem_seg_name == -1) {
        // Version 6 Unix/Linux/Mac client 
        if (attach_shmem_mmap( MMAPPED_FILE_NAME, (void**)&app_client_shm->shm)) {
            delete app_client_shm;
            app_client_shm = NULL;
        }
    } else {
        // EMX or version 5 Unix/Linux/Mac client
        if (attach_shmem(aid.shmem_seg_name, (void**)&app_client_shm->shm)) {
            delete app_client_shm;
            app_client_shm = NULL;
        }
    }
#endif  // ! _WIN32
    if (app_client_shm == NULL) return -1;
    return 0;
}

// Return CPU time of worker thread (and optionally others)
// This may be called from any thread
//
double boinc_worker_thread_cpu_time() {
    double cpu;
#ifdef _WIN32
    int retval;
    if (options.all_threads_cpu_time) {
        retval = boinc_process_cpu_time(cpu);
    } else {
        retval = boinc_thread_cpu_time(worker_thread_handle, cpu);
    }
    if (retval) {
        cpu = nrunning_ticks * TIMER_PERIOD;   // for Win9x
    }
#else
#ifdef GETRUSAGE_IN_TIMER_THREAD
    struct rusage worker_thread_ru;
    getrusage(RUSAGE_SELF, &worker_thread_ru);
#endif
    cpu = (double)worker_thread_ru.ru_utime.tv_sec
      + (((double)worker_thread_ru.ru_utime.tv_usec)/1000000.0);
    cpu += (double)worker_thread_ru.ru_stime.tv_sec
      + (((double)worker_thread_ru.ru_stime.tv_usec)/1000000.0);
#endif

#if 0
    // The following paranoia is (I hope) not needed anymore.
    // In any case, the check for CPU incrementing faster than real time
    // is misguided - it assumes no multi-threading.
    //
    static double last_cpu=0;
        // last value returned by this func
    static time_t last_time=0;
        // when it was returned
    time_t now = time(0);
    double time_diff = (double)(now - last_time);
    if (!finite(cpu)) {
        fprintf(stderr, "CPU time infinite or NaN\n");
        last_time = now;
        return last_cpu;
    }
    double cpu_diff = cpu - last_cpu;
    if (cpu_diff < 0) {
        fprintf(stderr, "Negative CPU time change\n");
        last_time = now;
        return last_cpu;
    }
    if (cpu_diff>(time_diff + 1)) {
        fprintf(stderr, "CPU time incrementing faster than real time.  Correcting.\n");
        cpu = last_cpu + time_diff + 1;         // allow catch-up
    }
    last_cpu = cpu;
    last_time = now;
#endif
    return cpu;
}

// Communicate to the core client (via shared mem)
// the current CPU time and fraction done.
// NOTE: various bugs could cause some of these FP numbers to be enormous,
// possibly overflowing the buffer.
// So use strlcat() instead of strcat()
//
// This is called only from the timer thread (so no need for synch)
//
static bool update_app_progress(double cpu_t, double cp_cpu_t) {
    char msg_buf[MSG_CHANNEL_SIZE], buf[256];

    if (standalone) return true;

    sprintf(msg_buf,
        "<current_cpu_time>%e</current_cpu_time>\n"
        "<checkpoint_cpu_time>%e</checkpoint_cpu_time>\n",
        cpu_t, cp_cpu_t
    );
    if (want_network) {
        strlcat(msg_buf, "<want_network>1</want_network>\n", MSG_CHANNEL_SIZE);
    }
    if (fraction_done >= 0) {
        double range = aid.fraction_done_end - aid.fraction_done_start;
        double fdone = aid.fraction_done_start + fraction_done*range;
        sprintf(buf, "<fraction_done>%e</fraction_done>\n", fdone);
        strlcat(msg_buf, buf, MSG_CHANNEL_SIZE);
    }
    if (fpops_per_cpu_sec) {
        sprintf(buf, "<fpops_per_cpu_sec>%e</fpops_per_cpu_sec>\n", fpops_per_cpu_sec);
        strlcat(msg_buf, buf, MSG_CHANNEL_SIZE);
    }
    if (fpops_cumulative) {
        sprintf(buf, "<fpops_cumulative>%e</fpops_cumulative>\n", fpops_cumulative);
        strlcat(msg_buf, buf, MSG_CHANNEL_SIZE);
    }
    if (intops_per_cpu_sec) {
        sprintf(buf, "<intops_per_cpu_sec>%e</intops_per_cpu_sec>\n", intops_per_cpu_sec);
        strlcat(msg_buf, buf, MSG_CHANNEL_SIZE);
    }
    if (intops_cumulative) {
        sprintf(buf, "<intops_cumulative>%e</intops_cumulative>\n", intops_cumulative);
        strlcat(msg_buf, buf, MSG_CHANNEL_SIZE);
    }
    return app_client_shm->shm->app_status.send_msg(msg_buf);
}

int boinc_init() {
    int retval;
    if (!diagnostics_is_initialized()) {
        retval = boinc_init_diagnostics(BOINC_DIAG_DEFAULTS);
        if (retval) return retval;
    }
    boinc_options_defaults(options);
    return boinc_init_options(&options);
}

int boinc_init_options(BOINC_OPTIONS* opt) {
    int retval;
    if (!diagnostics_is_initialized()) {
        retval = boinc_init_diagnostics(BOINC_DIAG_DEFAULTS);
        if (retval) return retval;
    }
    retval = boinc_init_options_general(*opt);
    if (retval) return retval;
    retval = start_timer_thread();
    if (retval) return retval;
#ifndef _WIN32
    retval = start_worker_signals();
    if (retval) return retval;
#endif
    return 0;
}

int boinc_init_options_general(BOINC_OPTIONS& opt) {
    int retval;
    options = opt;

    boinc_status.no_heartbeat = false;
    boinc_status.suspended = false;
    boinc_status.quit_request = false;
    boinc_status.abort_request = false;

    if (options.main_program) {
        // make sure we're the only app running in this slot
        //
        retval = file_lock.lock(LOCKFILE);
        if (retval) {
            // give any previous occupant a chance to timeout and exit
            //
            boinc_sleep(LOCKFILE_TIMEOUT_PERIOD);
            retval = file_lock.lock(LOCKFILE);
        }
        if (retval) {
            fprintf(stderr, "Can't acquire lockfile - exiting\n");
            boinc_exit(0);           // not un-recoverable ==> status=0
        }
    }

    retval = boinc_parse_init_data_file();
    if (retval) {
        standalone = true;
    } else {
        retval = setup_shared_mem();
        if (retval) {
            fprintf(stderr,
                "Can't set up shared mem: %d\n"
                "Will run in standalone mode.\n",
                retval
            );
            standalone = true;
        }
    }

    // copy the WU CPU time to a separate var,
    // since we may reread the structure again later.
    //
    initial_wu_cpu_time = aid.wu_cpu_time;

    fraction_done = -1;
    time_until_checkpoint = (int)aid.checkpoint_period;
    last_checkpoint_cpu_time = aid.wu_cpu_time;
    time_until_fraction_done_update = (int)aid.fraction_done_update_period;
    last_wu_cpu_time = aid.wu_cpu_time;

    if (standalone) {
        options.check_heartbeat = false;
    }
    heartbeat_giveup_time = interrupt_count + HEARTBEAT_GIVEUP_COUNT;

    return 0;
}

int boinc_get_status(BOINC_STATUS *s) {
    s->no_heartbeat = boinc_status.no_heartbeat;
    s->suspended = boinc_status.suspended;
    s->quit_request = boinc_status.quit_request;
    s->reread_init_data_file = boinc_status.reread_init_data_file;
    s->abort_request = boinc_status.abort_request;
    s->working_set_size = boinc_status.working_set_size;
    s->max_working_set_size = boinc_status.max_working_set_size;
    return 0;
}

// if we have any new trickle-ups or file upload requests,
// send a message describing them
//
static void send_trickle_up_msg() {
    char buf[MSG_CHANNEL_SIZE];
    BOINCINFO("Sending Trickle Up Message");
    strcpy(buf, "");
    if (have_new_trickle_up) {
        strcat(buf, "<have_new_trickle_up/>\n");
    }
    if (have_new_upload_file) {
        strcat(buf, "<have_new_upload_file/>\n");
    }
    if (strlen(buf)) {
        if (app_client_shm->shm->trickle_up.send_msg(buf)) {
            have_new_trickle_up = false;
            have_new_upload_file = false;
        }
    }
}

// NOTE: a non-zero status tells the core client that we're exiting with 
// an "unrecoverable error", which will be reported back to server. 
// A zero exit-status tells the client we've successfully finished the result.
//
int boinc_finish(int status) {
    fraction_done = 1;
    fprintf(stderr, "called boinc_finish\n");
    boinc_sleep(2.0);   // let the timer thread send final messages
    g_sleep = true;     // then disable it

    if (options.main_program && status==0) {
        FILE* f = fopen(BOINC_FINISH_CALLED_FILE, "w");
        if (f) fclose(f);
    }
    if (options.send_status_msgs) {
        aid.wu_cpu_time = last_checkpoint_cpu_time;
        boinc_write_init_data_file(aid);
    }

    boinc_exit(status);

    return 0;   // never reached
}

// unlock the lockfile and call the appropriate exit function
// Unix: called only from the worker thread.
// Win: called from the worker or timer thread.
//
// make static eventually
void boinc_exit(int status) {
    if (options.backwards_compatible_graphics) {
        graphics_cleanup();
    }
    
    file_lock.unlock(LOCKFILE);

    fflush(NULL);

    boinc_finish_diag();

    // various platforms have problems shutting down a process
    // while other threads are still executing,
    // or triggering endless exit()/atexit() loops.
    //
    BOINCINFO("Exit Status: %d", status);
#if   defined(_WIN32)
    // Halts all the threads and then cleans up.
    TerminateProcess(GetCurrentProcess(), status);
#elif defined(__APPLE_CC__)
    // stops endless exit()/atexit() loops.
    _exit(status);
#else
    // POSIX exit call.
    exit(status);
#endif
}

int boinc_is_standalone() {
    if (standalone) return 1;
    return 0;
}

static void exit_from_timer_thread(int status) {
#ifdef _WIN32
    // this seems to work OK on Windows
    //
    boinc_exit(status);
#else
    // but on Unix there are synchronization problems;
    // set a flag telling the worker thread to exit
    //
    worker_thread_exit_status = status;
    worker_thread_exit_flag = true;
    pthread_exit(NULL);
#endif
}

// parse the init data file.
// This is done at startup, and also if a "reread prefs" message is received
//
int boinc_parse_init_data_file() {
    FILE* f;
    int retval;

    // in principle should free project_preferences here if it's nonzero

    memset(&aid, 0, sizeof(aid));
    strcpy(aid.user_name, "");
    strcpy(aid.team_name, "");
    aid.wu_cpu_time = 0;
    aid.user_total_credit = 0;
    aid.user_expavg_credit = 0;
    aid.host_total_credit = 0;
    aid.host_expavg_credit = 0;
    aid.checkpoint_period = DEFAULT_CHECKPOINT_PERIOD;
    aid.fraction_done_update_period = DEFAULT_FRACTION_DONE_UPDATE_PERIOD;

    if (!boinc_file_exists(INIT_DATA_FILE)) {
        fprintf(stderr,
            "Can't open init data file - running in standalone mode\n"
        );
        return ERR_FOPEN;
    }
    f = boinc_fopen(INIT_DATA_FILE, "r");
    retval = parse_init_data_file(f, aid);
    fclose(f);
    if (retval) {
        fprintf(stderr,
            "Can't parse init data file - running in standalone mode\n"
        );
        return retval;
    }
    return 0;
}

int boinc_write_init_data_file(APP_INIT_DATA& x) {
    FILE* f = boinc_fopen(INIT_DATA_FILE, "w");
    if (!f) return ERR_FOPEN;
    int retval = write_init_data_file(f, x);
    fclose(f);
    return retval;
}

int boinc_report_app_status(
    double cpu_time,
    double checkpoint_cpu_time,
    double _fraction_done
) {
    char msg_buf[MSG_CHANNEL_SIZE];
    if (standalone) return 0;

    sprintf(msg_buf,
        "<current_cpu_time>%10.4f</current_cpu_time>\n"
        "<checkpoint_cpu_time>%.15e</checkpoint_cpu_time>\n"
        "<fraction_done>%2.8f</fraction_done>\n",
        cpu_time,
        checkpoint_cpu_time,
        _fraction_done
    );
    app_client_shm->shm->app_status.send_msg(msg_buf);
    return 0;
}

int boinc_get_init_data_p(APP_INIT_DATA* app_init_data) {
    *app_init_data = aid;
    return 0;
}

int boinc_get_init_data(APP_INIT_DATA& app_init_data) {
    app_init_data = aid;
    return 0;
}

int boinc_wu_cpu_time(double& cpu_t) {
    cpu_t = last_wu_cpu_time;
    return 0;
}

// make static eventually
int suspend_activities() {
    BOINCINFO("Received Suspend Message");
#ifdef _WIN32
    if (options.direct_process_action) {
        SuspendThread(worker_thread_handle);
    }
#endif
    return 0;
}

// make static eventually
int resume_activities() {
    BOINCINFO("Received Resume Message");
#ifdef _WIN32
    if (options.direct_process_action) {
        ResumeThread(worker_thread_handle);
    }
#endif
    return 0;
}
int restore_activities() {
 int retval;
    if (boinc_status.suspended) {
	    retval = suspend_activities();
	    } else {
	        retval = resume_activities();
	    }
    return retval;
}

static void handle_heartbeat_msg() {
    char buf[MSG_CHANNEL_SIZE];
    double dtemp;

    if (app_client_shm->shm->heartbeat.get_msg(buf)) {
        if (match_tag(buf, "<heartbeat/>")) {
            heartbeat_giveup_time = interrupt_count + HEARTBEAT_GIVEUP_COUNT;
        }
        if (parse_double(buf, "<wss>", dtemp)) {
            boinc_status.working_set_size = dtemp;
        }
        if (parse_double(buf, "<max_wss>", dtemp)) {
            boinc_status.max_working_set_size = dtemp;
        }
    }
}

static void handle_upload_file_status() {
    char path[256], buf[256], log_name[256], *p;
    std::string filename;
    int status;

    relative_to_absolute("", path);
    DirScanner dirscan(path);
    while (dirscan.scan(filename)) {
        strcpy(buf, filename.c_str());
        if (strstr(buf, UPLOAD_FILE_STATUS_PREFIX) != buf) continue;
        strcpy(log_name, buf+strlen(UPLOAD_FILE_STATUS_PREFIX));
        FILE* f = boinc_fopen(filename.c_str(), "r");
        if (!f) {
            fprintf(stderr, "handle_file_upload_status: can't open %s\n", filename.c_str());
            continue;
        }
        p = fgets(buf, 256, f);
        fclose(f);
        if (p && parse_int(buf, "<status>", status)) {
            UPLOAD_FILE_STATUS uf;
            uf.name = std::string(log_name);
            uf.status = status;
            upload_file_status.push_back(uf);
        } else {
            fprintf(stderr, "handle_upload_file_status: can't parse %s\n", buf);
        }
    }
}

// handle trickle and file upload messages
//
static void handle_trickle_down_msg() {
    char buf[MSG_CHANNEL_SIZE];
    if (app_client_shm->shm->trickle_down.get_msg(buf)) {
        BOINCINFO("Received Trickle Down Message");
        if (match_tag(buf, "<have_trickle_down/>")) {
            have_trickle_down = true;
        }
        if (match_tag(buf, "<upload_file_status/>")) {
            handle_upload_file_status();
        }
    }
}

// runs in timer thread
//
static void handle_process_control_msg() {
    char buf[MSG_CHANNEL_SIZE];
    if (app_client_shm->shm->process_control_request.get_msg(buf)) {
        //fprintf(stderr, "%f: got %s\n", dtime(), buf);
        if (match_tag(buf, "<suspend/>")) {
            boinc_status.suspended = true;
            suspend_activities();
        }

        if (match_tag(buf, "<resume/>")) {
            boinc_status.suspended = false;
            resume_activities();
        }

        if (match_tag(buf, "<quit/>")) {
            BOINCINFO("Received quit message");
            boinc_status.quit_request = true;
            if (options.direct_process_action) {
                exit_from_timer_thread(0);
            }
        }
        if (match_tag(buf, "<abort/>")) {
            BOINCINFO("Received abort message");
            boinc_status.abort_request = true;
            if (options.direct_process_action) {
                diagnostics_set_aborted_via_gui();
#if   defined(_WIN32)
                // Cause a controlled assert and dump the callstacks.
                DebugBreak();
#elif defined(__APPLE__)
                PrintBacktrace();
#endif
                exit_from_timer_thread(EXIT_ABORTED_VIA_GUI);
            }
        }
        if (match_tag(buf, "<reread_app_info/>")) {
            boinc_status.reread_init_data_file = true;
        }
        if (match_tag(buf, "<network_available/>")) {
            have_network = 1;
        }
        parse_int(buf, "<ncpus_available>", ncpus_available);
    }
}

// The following is used by V6 apps so that graphics
// will work with pre-V6 clients.
// If we get a graphics message, run/kill the (separate) graphics app
//
//
struct GRAPHICS_APP {
    bool fullscreen;
#ifdef _WIN32
    HANDLE pid;
#else
    int pid;
#endif
    GRAPHICS_APP(bool f) {fullscreen=f;}
    void run(char* path) {
        int argc;
        char* argv[4];
        char abspath[1024];
#ifdef _WIN32
        _fullpath(abspath, path, 1024);
#else
        strcpy(abspath, path);
#endif
        argv[0] = GRAPHICS_APP_FILENAME;
        if (fullscreen) {
            argv[1] = "--fullscreen";
            argv[2] = 0;
            argc = 2;
        } else {
            argv[1] = 0;
            argc = 1;
        }
        int retval = run_program(0, abspath, argc, argv, 0, pid);
        if (retval) {
            pid = 0;
        }
    }
    bool is_running() {
        if (pid && process_exists(pid)) return true;
        pid = 0;
        return false;
    }
    void kill() {
        if (pid) {
            kill_program(pid);
            pid = 0;
        }
    }
};

static GRAPHICS_APP ga_win(false), ga_full(true);
static bool have_graphics_app;

// The following is for backwards compatibility with version 5 clients.
//
static inline void handle_graphics_messages() {
    static char graphics_app_path[1024];
    char buf[MSG_CHANNEL_SIZE];
    GRAPHICS_MSG m;
    static bool first=true;
    if (first) {
        first = false;
        boinc_resolve_filename(
            GRAPHICS_APP_FILENAME, graphics_app_path,
            sizeof(graphics_app_path)
        );
        // if the above returns "graphics_app", there was no link file,
        // so there's no graphics app
        //
        if (!strcmp(graphics_app_path, GRAPHICS_APP_FILENAME)) {
            have_graphics_app = false;
        } else {
            have_graphics_app = true;
            app_client_shm->shm->graphics_reply.send_msg(
                xml_graphics_modes[MODE_HIDE_GRAPHICS]
            );
        }
    }

    if (!have_graphics_app) return;

    if (app_client_shm->shm->graphics_request.get_msg(buf)) {
        app_client_shm->decode_graphics_msg(buf, m);
        switch (m.mode) {
        case MODE_HIDE_GRAPHICS:
            if (ga_full.is_running()) {
                ga_full.kill();
            } else if (ga_win.is_running()) {
                ga_win.kill();
            }
            break;
        case MODE_WINDOW:
            if (!ga_win.is_running()) ga_win.run(graphics_app_path);
            break;
        case MODE_FULLSCREEN:
            if (!ga_full.is_running()) ga_full.run(graphics_app_path);
            break;
        case MODE_BLANKSCREEN:
            // we can't actually blank the screen; just kill the app
            //
            if (ga_full.is_running()) {
                ga_full.kill();
            }
            break;
        }
        app_client_shm->shm->graphics_reply.send_msg(
            xml_graphics_modes[m.mode]
        );
    }
}

static void graphics_cleanup() {
    if (!have_graphics_app) return;
    if (ga_full.is_running()) ga_full.kill();
    if (ga_win.is_running()) ga_win.kill();
}

// timer handler; runs in the timer thread
//
static void timer_handler() {
    if (g_sleep) return;
    interrupt_count++;

    // handle messages from the core client
    //
    if (app_client_shm) {
        handle_heartbeat_msg();
        if (options.handle_trickle_downs) {
            handle_trickle_down_msg();
        }
        if (in_critical_section==0 && options.handle_process_control) {
            handle_process_control_msg();
        }
        if (options.backwards_compatible_graphics) {
            handle_graphics_messages();
        }
    }

    if (interrupt_count % TIMERS_PER_SEC) return;

    // here it we're at a one-second boundary; do slow stuff
    //

    if (!ready_to_checkpoint) {
        time_until_checkpoint -= 1;
        if (time_until_checkpoint <= 0) {
            ready_to_checkpoint = true;
        }
    }

    // see if the core client has died, which means we need to die too
    // (unless we're in a critical section)
    //
    if (in_critical_section==0 && options.check_heartbeat) {
        if (heartbeat_giveup_time < interrupt_count) {
            fprintf(stderr,
                "No heartbeat from core client for 30 sec - exiting\n"
            );
            if (options.direct_process_action) {
                exit_from_timer_thread(0);
            } else {
                boinc_status.no_heartbeat = true;
            }
        }
    }

    // don't bother reporting CPU time etc. if we're suspended
    //
    if (options.send_status_msgs && !boinc_status.suspended) {
        time_until_fraction_done_update -= 1;
        if (time_until_fraction_done_update <= 0) {
            double cur_cpu;
            cur_cpu = boinc_worker_thread_cpu_time();
            last_wu_cpu_time = cur_cpu + initial_wu_cpu_time;
            update_app_progress(last_wu_cpu_time, last_checkpoint_cpu_time);
            time_until_fraction_done_update = (int)aid.fraction_done_update_period;
        }
    }
    if (options.handle_trickle_ups) {
        send_trickle_up_msg();
    }
    if (timer_callback) {
        timer_callback();
    }
}

#ifdef _WIN32

UINT WINAPI timer_thread(void *) {
     
    while (1) {
        Sleep(TIMER_PERIOD*1000);
        timer_handler();

        // poor man's CPU time accounting for Win9x
        //
        if (!boinc_status.suspended) {
            nrunning_ticks++;
        }
    }
    return 0;
}

#else

static void* timer_thread(void*) {
    block_sigalrm();
    while(1) {
        boinc_sleep(TIMER_PERIOD);
        timer_handler();
    }
    return 0;
}

// This SIGALRM handler gets handled only by the worker thread.
// It gets CPU time and implements sleeping.
// It must call only signal-safe functions, and must not do FP math
//
static void worker_signal_handler(int) {
#ifndef GETRUSAGE_IN_TIMER_THREAD
    getrusage(RUSAGE_SELF, &worker_thread_ru);
#endif
    if (worker_thread_exit_flag) {
        boinc_exit(worker_thread_exit_status);
    }
    if (options.direct_process_action) {
        while (boinc_status.suspended && in_critical_section==0) {
            sleep(1);   // don't use boinc_sleep() because it does FP math
        }
    }
}

#endif


// Called from the worker thread; create the timer thread
//
int start_timer_thread() {
    int retval=0;

#ifdef _WIN32

    // get the worker thread handle
    //
    DuplicateHandle(
        GetCurrentProcess(),
        GetCurrentThread(),
        GetCurrentProcess(),
        &worker_thread_handle,
        0,
        FALSE,
        DUPLICATE_SAME_ACCESS
    );

    // Create the timer thread
    //
    uintptr_t thread;
    UINT      uiThreadId;
    thread = _beginthreadex(
        NULL,
        16384,       // stack size
        timer_thread,
        0,
        0,
        &uiThreadId
    );

    if (!thread) {
        fprintf(stderr, "start_timer_thread(): _beginthreadex() failed, errno %d\n", errno);
        return errno;
    }
    
    // lower our (worker thread) priority
    //
    SetThreadPriority(worker_thread_handle, THREAD_PRIORITY_IDLE);
#else
    pthread_attr_t thread_attrs;
    pthread_attr_init(&thread_attrs);
    pthread_attr_setstacksize(&thread_attrs, 16384);
    retval = pthread_create(&timer_thread_handle, &thread_attrs, timer_thread, NULL);
    if (retval) {
        fprintf(stderr, "start_timer_thread(): pthread_create(): %d", retval);
        return retval;
    }
#endif
    return 0;
}

#ifndef _WIN32
// set up a periodic SIGALRM, to be handled by the worker thread
//
static int start_worker_signals() {
    int retval;
    struct sigaction sa;
    itimerval value;
    sa.sa_handler = worker_signal_handler;
    sa.sa_flags = SA_RESTART;
    sigemptyset(&sa.sa_mask);
    retval = sigaction(SIGALRM, &sa, NULL);
    if (retval) {
        perror("boinc start_timer_thread() sigaction");
        return retval;
    }
    value.it_value.tv_sec = 0;
    value.it_value.tv_usec = (int)(TIMER_PERIOD*1e6);
    value.it_interval = value.it_value;
    retval = setitimer(ITIMER_REAL, &value, NULL);
    if (retval) {
        perror("boinc start_timer_thread() setitimer");
        return retval;
    }
    return 0;
}
#endif

int boinc_send_trickle_up(char* variety, char* p) {
    if (!options.handle_trickle_ups) return ERR_NO_OPTION;
    FILE* f = boinc_fopen(TRICKLE_UP_FILENAME, "wb");
    if (!f) return ERR_FOPEN;
    fprintf(f, "<variety>%s</variety>\n", variety);
    size_t n = fwrite(p, strlen(p), 1, f);
    fclose(f);
    if (n != 1) return ERR_WRITE;
    have_new_trickle_up = true;
    return 0;
}

int boinc_time_to_checkpoint() {
    if (ready_to_checkpoint) {
        boinc_begin_critical_section();
        return 1;
    }
    return 0;
}

int boinc_checkpoint_completed() {
    double cur_cpu;
    cur_cpu = boinc_worker_thread_cpu_time();
    last_wu_cpu_time = cur_cpu + aid.wu_cpu_time;
    last_checkpoint_cpu_time = last_wu_cpu_time;
    time_until_checkpoint = (int)aid.checkpoint_period;
    boinc_end_critical_section();
    ready_to_checkpoint = false;

    return 0;
}

void boinc_begin_critical_section() {
    in_critical_section++;
}

void boinc_end_critical_section() {
    in_critical_section--;
    if (in_critical_section < 0) {
        in_critical_section = 0;        // just in case
    }
}

int boinc_fraction_done(double x) {
    fraction_done = x;
    return 0;
}

int boinc_receive_trickle_down(char* buf, int len) {
    std::string filename;
    char path[256];

    if (!options.handle_trickle_downs) return false;

    if (have_trickle_down) {
        relative_to_absolute("", path);
        DirScanner dirscan(path);
        while (dirscan.scan(filename)) {
            fprintf(stderr, "scan: %s\n", filename.c_str());
            if (strstr(filename.c_str(), "trickle_down")) {
                strncpy(buf, filename.c_str(), len);
                return true;
            }
        }
        have_trickle_down = false;
    }
    return false;
}

int boinc_upload_file(std::string& name) {
    char buf[256];
    std::string pname;
    int retval;

    retval = boinc_resolve_filename_s(name.c_str(), pname);
    if (retval) return retval;
    sprintf(buf, "%s%s", UPLOAD_FILE_REQ_PREFIX, name.c_str());
    FILE* f = boinc_fopen(buf, "w");
    if (!f) return ERR_FOPEN;
    have_new_upload_file = true;
    fclose(f);
    return 0;
}


int boinc_upload_status(std::string& name) {
    for (unsigned int i=0; i<upload_file_status.size(); i++) {
        UPLOAD_FILE_STATUS& ufs = upload_file_status[i];
        if (ufs.name == name) {
            return ufs.status;
        }
    }
    return ERR_NOT_FOUND;
}

void boinc_ops_per_cpu_sec(double fp, double i) {
    fpops_per_cpu_sec = fp;
    intops_per_cpu_sec = i;
}

void boinc_ops_cumulative(double fp, double i) {
    fpops_cumulative = fp;
    intops_cumulative = i;
}

void boinc_need_network() {
    want_network = 1;
    have_network = 0;
}

int boinc_network_poll() {
    return have_network?0:1;
}

void boinc_network_done() {
    want_network = 0;
}

#ifndef _WIN32
// block SIGALRM, so that the worker thread will be forced to handle it
//
static void block_sigalrm() {
    sigset_t mask;
    sigemptyset(&mask);
    sigaddset(&mask, SIGALRM);
    pthread_sigmask(SIG_BLOCK, &mask, NULL);
}
#endif

void boinc_register_timer_callback(FUNC_PTR p) {
    timer_callback = p;
}

double boinc_get_fraction_done() {
    return fraction_done;
}

int boinc_ncpus_available() {
    return ncpus_available;
}

void boinc_nthreads(int n) {
    char msg_buf[MSG_CHANNEL_SIZE];

    nthreads = n;
    if (standalone) return;
    sprintf(msg_buf, "<nthreads>%d</nthreads>", n);
    return app_client_shm->shm->process_control_reply.send_msg_overwrite(msg_buf);
}

const char *BOINC_RCSID_0fa0410386 = "$Id$";