stopsmoking.c

#include <errno.h>
#include <fcntl.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <syslog.h>
#include <time.h>
#include <unistd.h>

int fifod;
char sharr[128];

void logErrorMsg(char *msg) {
    char completeMsg[512] = "";

    time_t t = time(NULL);
    struct tm *tm = localtime(&t);

    sprintf(completeMsg, "[%02d-%02d-%04d %02d:%02d:%02d] %s\n", tm->tm_mday, tm->tm_mon + 1, tm->tm_year + 1900, tm->tm_hour, tm->tm_min, tm->tm_sec, msg);

    syslog(LOG_ALERT, "%s", completeMsg);

    if (write(STDERR_FILENO, completeMsg, strlen(completeMsg)) < 0) {
        exit(EXIT_FAILURE);
    }
}

void logOutputMsg(char *msg) {
    char completeMsg[512] = "";

    time_t t = time(NULL);
    struct tm *tm = localtime(&t);

    sprintf(completeMsg, "[%02d-%02d-%04d %02d:%02d:%02d] %s\n", tm->tm_mday, tm->tm_mon + 1, tm->tm_year + 1900, tm->tm_hour, tm->tm_min, tm->tm_sec, msg);

    syslog(LOG_NOTICE, "%s", completeMsg);

    if (write(STDOUT_FILENO, completeMsg, strlen(completeMsg)) < 0) {
        exit(EXIT_FAILURE);
    }
}

void readConfigData(unsigned *cigarettes, unsigned *starthour, unsigned *finishhour, unsigned *today, time_t *dateadded, time_t *dateupdated, time_t *datelastquit) {
    /* Files */
    FILE *confFile;
    char home[64] = "/home/";
    strcat(home, getenv("USER"));
    char configFilePath[256] = "";

    /* Open config file */
    strcat(configFilePath, home);
    strcat(configFilePath, "/.config/stopsmoking/config");

    if ((confFile = fopen(configFilePath, "r")) == NULL) {
        logErrorMsg("Can't open config file. EXIT");
        exit(EXIT_FAILURE);
    }

    /* Read into variables */
    char tmp[256] = "";
    if (feof(confFile) || fscanf(confFile, "%[^=]=%u\n", tmp, cigarettes) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }
    if (feof(confFile) || fscanf(confFile, "%[^=]=%u", tmp, starthour) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }
    if (feof(confFile) || fscanf(confFile, "%[^=]=%u", tmp, finishhour) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }
    if (feof(confFile) || fscanf(confFile, "%[^=]=%u", tmp, today) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }
    if (feof(confFile) || fscanf(confFile, "%[^=]=%lu", tmp, dateadded) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }
    if (feof(confFile) || fscanf(confFile, "%[^=]=%lu", tmp, dateupdated) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }
    if (feof(confFile) || fscanf(confFile, "%[^=]=%lu", tmp, datelastquit) != 2) {
        logErrorMsg("Illegal config file. EXIT");
        fclose(confFile);
        exit(EXIT_FAILURE);
    }

    fclose(confFile);
}

void updateInConfig(unsigned cigarettes, unsigned starthour, unsigned finishhour, unsigned today, time_t dateadded, time_t *dateupdated, time_t datelastquit) {
    /* Files */
    FILE *confFile;
    char home[64] = "/home/";
    strcat(home, getenv("USER"));
    char configFilePath[256] = "";

    /* Open config file */
    strcat(configFilePath, home);
    strcat(configFilePath, "/.config/stopsmoking/config");

    if ((confFile = fopen(configFilePath, "w")) == NULL) {
        logErrorMsg("Could not open config file. EXIT");
        exit(EXIT_FAILURE);
    }

    fprintf(confFile, "Cigarettes=%d\n", cigarettes);
    fprintf(confFile, "Starthour=%d\n", starthour);
    fprintf(confFile, "Finishhour=%d\n", finishhour);
    fprintf(confFile, "Today=%d\n", today);
    fprintf(confFile, "DateAdded=%lu\n", dateadded);

    time_t t = time(NULL);
    *dateupdated = t;
    fprintf(confFile, "DateUpdated=%lu\n", *dateupdated);
    fprintf(confFile, "DateLastQuit=%lu\n", datelastquit);

    fclose(confFile);
}

void updateToday(unsigned cigarettes, unsigned starthour, unsigned finishhour, unsigned *today, time_t dateadded, time_t *dateupdated, time_t datelastquit) {
    *today = cigarettes;

    updateInConfig(cigarettes, starthour, finishhour, *today, dateadded, dateupdated, datelastquit);
}

void computeSleepTime(unsigned *sleepTime, unsigned *probabilityToSmoke, unsigned cigarettes, unsigned starthour, unsigned finishhour, unsigned today, time_t dateadded, time_t *dateupdated, time_t datelastquit) {
    unsigned short remaining;

    /* Current time */
    time_t t = time(NULL);
    struct tm tm = *localtime(&t);

    /* Date added */
    time_t t2 = dateadded;
    // struct tm tm2 = *localtime(&t2);

    /* Date updated */
    time_t t3 = *dateupdated;
    struct tm tm3 = *localtime(&t3);

    if (t < t2) {  // Future => Exception
        logErrorMsg("Starts in the future!");
        exit(EXIT_FAILURE);
    } else if (tm3.tm_yday == tm.tm_yday && tm3.tm_year == tm.tm_year) {  // Today
        updateInConfig(cigarettes, starthour, finishhour, today, dateadded, dateupdated, datelastquit);
        if (tm.tm_hour >= starthour && tm.tm_hour <= finishhour) {
            remaining = finishhour - tm.tm_hour;
        } else {
            remaining = 0;
        }
    } else {  // Older
        updateToday(cigarettes, starthour, finishhour, &today, dateadded, dateupdated, datelastquit);
        if (tm.tm_hour >= starthour && tm.tm_hour <= finishhour) {
            remaining = finishhour - tm.tm_hour;
        } else {
            remaining = 0;
        }
    }

    if (remaining > 0) {
        *probabilityToSmoke = 25;
        *sleepTime = (unsigned)(60 * today / (remaining)) * 60 / 4;
    } else {
        *probabilityToSmoke = 0;
        *sleepTime = 30 * 60;
    }

    char msg[512];
    sprintf(msg, "Started with the probability of: %d", *probabilityToSmoke);
    logOutputMsg(msg);
}

void tellToSmoke(unsigned today) {
    if (strlen(sharr) == 128) {
        memset(sharr, '\0', sizeof(sharr));
    }
    sharr[strlen(sharr)] = (char)today;
    write(fifod, sharr, sizeof(sharr));
    logOutputMsg("Smoke!!!");
}

void tryToSmoke(unsigned probabilityToSmoke, unsigned cigarettes, unsigned starthour, unsigned finishhour, unsigned *today, time_t dateadded, time_t *dateupdated, time_t datelastquit) {
    srand(time(NULL));
    int smoke = (rand() % 100) < probabilityToSmoke;

    if (smoke && *today) {
        tellToSmoke(*today);
        --(*today);
        updateInConfig(cigarettes, starthour, finishhour, *today, dateadded, dateupdated, datelastquit);
    }
}

void tryToQuit(unsigned probabilityToSmoke, time_t *datelastquit, unsigned *cigarettes, unsigned *starthour, unsigned *finishhour, unsigned *today, time_t *dateadded, time_t *dateupdated) {
    /* Current time */
    time_t t = time(NULL);
    // struct tm tm = *localtime(&t);

    /* Date last quit */
    time_t t2 = *datelastquit;
    // struct tm tm2 = *localtime(&t2);

    int diff = difftime(t, t2) / (60 * 60 * 24);

    if (diff >= 2) {
        srand(time(NULL));
        int quit = (rand() % 100) < (double)probabilityToSmoke / 2;
        if (quit && *cigarettes) {
            logOutputMsg("Quitted 1 cigarette!!!");
            --(*cigarettes);
            *datelastquit = t;
            updateInConfig(*cigarettes, *starthour, *finishhour, *today, *dateadded, dateupdated, *datelastquit);
        }
    }
}

void createFifo() {
    char *pipeName = "/tmp/fifostopsmoking";

    /* Make pipe */
    mkfifo(pipeName, 0666);

    fifod = open(pipeName, O_CREAT | O_WRONLY);
    if (fifod < 0) {
        logErrorMsg("Can't create fifo pipe");
        exit(EXIT_FAILURE);
    }

    /* Reset shared array */
    memset(sharr, '\0', sizeof(sharr));
}

void resetpipe(){
    if (strlen(sharr) == 128) {
        memset(sharr, '\0', sizeof(sharr));
    }
    sharr[strlen(sharr)] = (char)255;
    write(fifod, sharr, sizeof(sharr));
    logOutputMsg("Reseted pipe");
    
}

int canTry(unsigned today, unsigned starthour, unsigned finishhour) {
    if (today == 0)
        return 0;

    /* Current time */
    time_t t = time(NULL);
    struct tm tm = *localtime(&t);

    if (tm.tm_hour < starthour || tm.tm_hour > finishhour)
        return 0;

    return 1;
}

void checkDayChange(unsigned *sleepTime, unsigned *probabilityToSmoke, unsigned cigarettes, unsigned starthour, unsigned finishhour, unsigned *today, time_t dateadded, time_t *dateupdated, time_t datelastquit) {
    /* Current time */
    time_t t = time(NULL);
    struct tm tm = *localtime(&t);

    /* Date updated */
    time_t t2 = *dateupdated;
    struct tm tm2 = *localtime(&t2);

    if (tm.tm_hour > finishhour && *today) {
        while (*today) {
            tellToSmoke(*today);
            --(*today);
        }
        updateInConfig(cigarettes, starthour, finishhour, *today, dateadded, dateupdated, datelastquit);
    }

    if (*probabilityToSmoke != 0 && tm.tm_yday == tm2.tm_yday && tm.tm_year == tm2.tm_year)
        return;

    *today = cigarettes;
    resetpipe();
    computeSleepTime(sleepTime, probabilityToSmoke, cigarettes, starthour, finishhour, *today, dateadded, dateupdated, datelastquit);

    
}

int main(void) {
    /* Our process ID and Session ID */
    pid_t pid, sid;

    /* Smoking variables */
    unsigned cigarettes;
    unsigned starthour;
    unsigned finishhour;
    unsigned today;
    time_t dateadded;
    time_t dateupdated;
    time_t datelastquit;
    unsigned probabilityToSmoke;

    /* Sleep time */
    unsigned sleepTime = 2;

    /* Fork off the parent process */
    pid = fork();
    if (pid < 0) {
        exit(EXIT_FAILURE);
    }
    /* If we got a good PID, then
       we can exit the parent process. */
    if (pid > 0) {
        logOutputMsg("Parent exited successfully");
        exit(EXIT_SUCCESS);
    }

    /* Change the file mode mask */
    umask(0);

    /* Open any logs here */
    // struct stat st = {0};
    // if (stat("/var/log/stopsmoking", &st) == -1) {
    //     mkdir("/var/log/stopsmoking", 0755);
    // }

    /* Create a new SID for the child process */
    sid = setsid();
    if (sid < 0) {
        /* Log the failure */
        logErrorMsg("Can't allocate SID. EXIT");
        exit(EXIT_FAILURE);
    }

    /* Change the current working directory */
    if ((chdir("/")) < 0) {
        /* Log the failure */
        logErrorMsg("Can't change cwd. EXIT");
        exit(EXIT_FAILURE);
    }

    /* Daemon-specific initialization goes here */
    readConfigData(&cigarettes, &starthour, &finishhour, &today, &dateadded, &dateupdated, &datelastquit);
    createFifo();
    computeSleepTime(&sleepTime, &probabilityToSmoke, cigarettes, starthour, finishhour, today, dateadded, &dateupdated, datelastquit);

    logOutputMsg("Service started successfully");

    /* The Big Loop */
    while (1) {
        /* Check for configuration changes*/
        unsigned starthourbak = starthour, finishhourbak = finishhour, todaybak = today, dateaddedbak = dateadded;
        readConfigData(&cigarettes, &starthour, &finishhour, &today, &dateadded, &dateupdated, &datelastquit);
        if (starthourbak != starthour || finishhourbak != finishhour || todaybak != today || dateaddedbak != dateadded){
            computeSleepTime(&sleepTime, &probabilityToSmoke, cigarettes, starthour, finishhour, today, dateadded, &dateupdated, datelastquit);
            resetpipe();
        }

        /* Check if it can try */
        if (canTry(today, starthour, finishhour)) {
            checkDayChange(&sleepTime, &probabilityToSmoke, cigarettes, starthour, finishhour, &today, dateadded, &dateupdated, datelastquit);
            logOutputMsg("Another try");
            tryToSmoke(probabilityToSmoke, cigarettes, starthour, finishhour, &today, dateadded, &dateupdated, datelastquit);
            tryToQuit(probabilityToSmoke, &datelastquit, &cigarettes, &starthour, &finishhour, &today, &dateadded, &dateupdated);
        } else {
            /* If it can't try, check for date change */
            checkDayChange(&sleepTime, &probabilityToSmoke, cigarettes, starthour, finishhour, &today, dateadded, &dateupdated, datelastquit);
        }
        // exit(EXIT_SUCCESS);

        sleep(sleepTime); /* wait sleepTime seconds */
    }

    /* Close out the standard file descriptors */
    close(STDIN_FILENO);
    close(STDOUT_FILENO);
    close(STDERR_FILENO);

    exit(EXIT_SUCCESS);
}