trick/trick_source/sim_services/MasterSlave/MSSharedMem.cpp

#include <iostream>
#include <sstream>
#include <cstring> // for memcpy
#include <unistd.h>

#include "trick/MSSharedMem.hh"
#include "trick/tsm_proto.h"
#include "trick/command_line_protos.h"

Trick::MSSharedMem::MSSharedMem() : tsm_dev() {
    tsm_dev.default_val = -1;

    // default is a non-zero sync wait limit; helpful when slave reading initial data from master
    sync_wait_limit = 5.0 ;
}

Trick::MSSharedMem::~MSSharedMem() {
    // detach shared memory
    tsm_disconnect(&tsm_dev);
}

int Trick::MSSharedMem::set_sync_wait_limit(double in_limit) {
    /** @par Detailed Design */
    if ( in_limit > 0.0 ) {
        /** @li if the incoming limit time is greater than zero, we will use it 
                as the timeout value during read and write */
        sync_wait_limit = in_limit ;
    } else {
        /** @li if the incoming limit time is less than or equal to zero, wait forever */
        sync_wait_limit = TSM_MAX_TIMEOUT_LIMIT;
    }
    return(0) ;
}

std::string Trick::MSSharedMem::add_sim_args(std::string slave_type __attribute__((unused))) {

    /** @par Detailed Design */

    /** @li nothing to do here for shared memory. */
    return("");
}

int Trick::MSSharedMem::process_sim_args() {

    //int ii ;
    //int argc ;
    //char ** argv ;

    //argc = command_line_args_get_argc() ;
    //argv = command_line_args_get_argv() ;

    /** @par Detailed Design */

    /** @li no shared memory arguments to search for, return 1 to enable slave */
    //for (ii = 2; ii < argc; ii++) {
    //}
    return(1) ;
}

int Trick::MSSharedMem::accept() {

    int ret ; 
    /** @par Detailed Design */
    /** @li Call tsm_init to create shared memory for master. */
    tsm_dev.size = sizeof(MSSharedMemData);
    ret = tsm_init(&tsm_dev);
    shm_addr = (MSSharedMemData*) tsm_dev.addr;
    /** @li Save master process id so we can keep master and slave data seperate. */
    // (the master calls accept)
    if (ret==TSM_SUCCESS) {
        shm_addr->master_pid = getpid();
//fprintf(stderr, "====accept master=%d\n", getpid());
        MSQ_INIT(shm_addr->master_time);
        MSQ_INIT(shm_addr->master_command);
        MSQ_INIT(shm_addr->slave_command);
        shm_addr->slave_port = MS_ERROR_PORT;
        shm_addr->chkpnt_name[0] = MS_ERROR_NAME;
    } else {
//fprintf(stderr, "====accept SHARED MEMORY ERROR\n");
    }
    return(ret) ;
}

int Trick::MSSharedMem::connect() {
    int ret ; 
    /** @par Detailed Design */
    /** @li Call tsm_init to create shared memory for slave. */
    if (tsm_dev.size == 0) {
        tsm_dev.size = sizeof(MSSharedMemData);
        ret = tsm_init(&tsm_dev);
    } else {
    // handle reconnecting for dmtcp restart
        ret = tsm_reconnect(&tsm_dev);
    }
    shm_addr = (MSSharedMemData*) tsm_dev.addr;
    return(ret) ;
}

int Trick::MSSharedMem::disconnect() {
    return(0) ;
}


double Trick::MSSharedMem::read_wait(struct timespec *in_start) {
    struct timespec ts_Current, ts_Difference;

    RELEASE();
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts_Current);
    if ((ts_Current.tv_nsec - in_start->tv_nsec) < 0) {
        ts_Difference.tv_sec = ts_Current.tv_sec - in_start->tv_sec - 1;
        ts_Difference.tv_nsec = 1000000000 + ts_Current.tv_nsec - in_start->tv_nsec;
    } else {
        ts_Difference.tv_sec = ts_Current.tv_sec - in_start->tv_sec;
        ts_Difference.tv_nsec = ts_Current.tv_nsec - in_start->tv_nsec;
    }
    // return the total elapsed time we've waited since in_start
    return ((double)ts_Difference.tv_nsec / 1000000000.0) + ts_Difference.tv_sec;
}

long long Trick::MSSharedMem::read_time() {

    long long in_time;
    double readtry_time = 0.0;
    struct timespec ts_Start;

    /** @par Detailed Design */
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts_Start);    

    /** @li Get time from shared memory */
    while (MSQ_ISEMPTY(shm_addr->master_time)) {
        if (readtry_time >= sync_wait_limit) {
            break;
        }
        readtry_time = read_wait(&ts_Start);
    }
    if (!MSQ_ISEMPTY(shm_addr->master_time)) {
        in_time = MSQ_FRONT(shm_addr->master_time);
//fprintf(stderr, "+++++read_time pid=%d time=%lld readtry=%f\n", getpid(), in_time, readtry_time);
        MSQ_POP(shm_addr->master_time);
        return (in_time) ;
    /** @li If no new data before timeout limit, return "error" time */
    } else {
//fprintf(stderr, "+++++read_time pid=%d time=%lld ERROR readtry=%f\n", getpid(), in_time, readtry_time,); fflush(stderr);
        return (MS_ERROR_TIME) ;
    }
}

MS_SIM_COMMAND Trick::MSSharedMem::read_command() {

    MS_SIM_COMMAND command;
    double readtry_time = 0.0;
    struct timespec ts_Start;

    /** @par Detailed Design */
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts_Start);    

    if (getpid() == shm_addr->master_pid) {
    /** @li Get slave command from shared memory */
    // I am master, so read slave command
        while (MSQ_ISEMPTY(shm_addr->slave_command)) {
            if (readtry_time >= sync_wait_limit) {
                break;
            }
            readtry_time = read_wait(&ts_Start);
        }
        if (!MSQ_ISEMPTY(shm_addr->slave_command)) {
            command = MSQ_FRONT(shm_addr->slave_command);
//fprintf(stderr, "+++++read_command pid=%d command=%d (from slave)\n", getpid(), command);
            MSQ_POP(shm_addr->slave_command);
            return (command) ;
        /** @li If no new data before timeout limit, return "error" command */
        } else {
//fprintf(stderr, "+++++read_command pid=%d command=%d (from slave) ERROR readtry=%f\n", getpid(), command, readtry_time);
            return (MS_ErrorCmd) ;
        }
    } else {
    /** @li Get master command from shared memory */
    // I am slave, so read master command
        while (MSQ_ISEMPTY(shm_addr->master_command)) {
            if (readtry_time >= sync_wait_limit) {
                break;
            }
            readtry_time = read_wait(&ts_Start);
        }
        if (!MSQ_ISEMPTY(shm_addr->master_command)) {
            command = MSQ_FRONT(shm_addr->master_command);
//fprintf(stderr, "+++++read_command pid=%d command=%d (from master)\n", getpid(), command);
            MSQ_POP(shm_addr->master_command);
            return (command) ;
        /** @li If no new data before timeout limit, return "error" command */
        } else {
//fprintf(stderr, "+++++read_command pid=%d command=%d (from master) ERROR readtry=%f\n", getpid(), command, readtry_time);
            return (MS_ErrorCmd) ;
        }
    }
}

int Trick::MSSharedMem::read_port() {

    int in_port;
    double readtry_time = 0.0;
    struct timespec ts_Start;

    /** @par Detailed Design */
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts_Start);    

    /** @li Get port number from shared memory */
    while (shm_addr->slave_port == MS_ERROR_PORT) {
        if (readtry_time >= sync_wait_limit) {
            break;
        }
        readtry_time = read_wait(&ts_Start);
    }
    if (shm_addr->slave_port != MS_ERROR_PORT) {
        in_port = shm_addr->slave_port;
        shm_addr->slave_port = MS_ERROR_PORT; // default value
        return (in_port) ;
    /** @li If no new data before timeout limit, return "error" port */
    } else {
        return (MS_ERROR_PORT) ;
    }
}

char Trick::MSSharedMem::read_name(char * read_data, size_t size) {

    double readtry_time = 0.0;
    struct timespec ts_Start;

    /** @par Detailed Design */
    clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts_Start);    

    /** @li Get name (character array) from shared memory */
    while (shm_addr->chkpnt_name[0] == MS_ERROR_NAME) {
        if (readtry_time >= sync_wait_limit) {
            break;
        }
        readtry_time = read_wait(&ts_Start);
    }
    if (shm_addr->chkpnt_name[0] != MS_ERROR_NAME) {
        memcpy(read_data, shm_addr->chkpnt_name, size);
        shm_addr->chkpnt_name[0] = MS_ERROR_NAME; // default value
        return (0) ;
    /** @li If no new data before timeout limit, return "error" name */
    } else {
        return (MS_ERROR_NAME) ;
    }
}

int Trick::MSSharedMem::write_time(long long in_time) {

    /** @par Detailed Design */
    /** @li Write time to shared memory */
//fprintf(stderr, "====write_time pid=%d time=%lld\n", getpid(), in_time);
    MSQ_PUSH(shm_addr->master_time, in_time);

    /** @li Return the number of bytes written */
    return(sizeof(long long)) ;
}

int Trick::MSSharedMem::write_command(MS_SIM_COMMAND command) {

    /** @par Detailed Design */
    /** @li Write command to shared memory */
    if (getpid() == shm_addr->master_pid) {
//fprintf(stderr, "====write_command pid=%d command=%d (master)\n", getpid(), command);
        MSQ_PUSH(shm_addr->master_command, command);
    } else {
//fprintf(stderr, "====write_command pid=%d command=%d (slave)\n", getpid(), command);
        MSQ_PUSH(shm_addr->slave_command, command);
    }

    /** @li Return the number of bytes written */
    return(sizeof(MS_SIM_COMMAND)) ;
}

int Trick::MSSharedMem::write_port(int in_port) {

    /** @par Detailed Design */
    /** @li Write port number to shared memory */
    shm_addr->slave_port = in_port;

    /** @li Return the number of bytes written */
    return(sizeof(int)) ;
}

int Trick::MSSharedMem::write_name(char * in_data, size_t size) {

    /** @par Detailed Design */
    /** @li Write name (character array) to shared memory */
    memcpy(shm_addr->chkpnt_name, in_data, size);

    /** @li Return the number of bytes written */
    return(size);
}