lovec.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>

char sign;
int energy;

void timestamp() {
    time_t ltime = time(NULL);
    char *timeStr = asctime(localtime(&ltime));
    timeStr[strlen(timeStr) - 1] = 0;
    printf("[%s]: ", timeStr);
}

void changeSign() {
    sign = sign == '.' ? '*' : '.';
}

void moreEnergy() {
    energy += 10;
    timestamp();
    printf("Juhu! Nova energija! (%d).\n", energy);
}

void newProcess() {
    int child = fork();
    timestamp();
    if(child == 0) {
        sleep((energy % 7) + 1);
        int status = (42 * energy) % 128;
        printf("Izhodni status childa: %d\n", status);
        exit(status);
    }
    else if(child > 0)
        printf("PID fork childa: %d\n", child);
}

void killZombie() {
    int status;
    wait(&status);
    if(WIFEXITED(status)) {
        status = WEXITSTATUS(status);
        timestamp();
        printf("Status zombija: %d\n", status);
    }
}

int main(int argc, char* argv[]) {
    int demon = fork();
    if(demon < 0) {
        timestamp();
        perror("Napaka pri forkanju! Demon se ni zagnal!");
        return 0;
    }
    else if(demon > 0)
        return 0;

    dup2(1, 2);
    freopen("lovec.log", "w", stdout);

    signal(SIGTERM, moreEnergy);
    signal(SIGUSR1, changeSign);
    signal(SIGUSR2, newProcess);
    signal(SIGCHLD, killZombie);

    timestamp();
    printf("PID: %d\n", getpid());

    energy = argc == 1 ? 42 : atoi(argv[1]);
    sign = '.';

    while(energy > 0) {
        printf("%c", sign);
        fflush(0);
        sleep(1);
        energy--;
    }
    printf("\n");

    timestamp();
    printf("Out of energy!\n");

    return 0;
}