A C application that logs some received signals to a file

signal_logger_test.c

//name: signal_logger_test.c
//how to comiple:
//${CC} signal_logger_test.c -o signal_logger_test

#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <time.h>

FILE *mylog;
time_t mytime;

int go_on = 1;
char signal_table[][12] ={
"NO 0 SIG",
" 1) HUP",
" 2) INT",
" 3) QUIT",
" 4) ILL",
" 5) TRAP",
" 6) ABRT",
" 7) BUS",
" 8) FPE",
" 9) KILL",
"10) USR1",
"11) SEGV",
"12) USR2",
"13) PIPE",
"14) ALRM",
"15) TERM",
"16) STKFLT",
"17) CHLD",
"18) CONT",
"19) STOP",
"20) TSTP",
"21) TTIN",
"22) TTOU",
"23) URG",
"24) XCPU",
"25) XFSZ",
"26) VTALRM",
"27) PROF",
"28) WINCH",
"29) POLL",
"30) PWR",
"31) SYS",
"32) RTMIN"
};

int counter = 1;

void signal_handler (int signum) {
    struct tm tm = *localtime(&mytime);

    fprintf(mylog, "[%d-%02d-%02d %02d:%02d:%02d] %s ( counter = %d )\n",  tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec, signal_table[signum], counter);
    fflush(mylog);
    printf("signal \"%s\" called!.\n", signal_table[signum]);

    if ( signum == SIGINT || signum == SIGTERM ) {
        go_on = 0;
    }
}

int main () {
    
    mytime = time(NULL);

    mylog = fopen("signal.log", "w");

    for (int mysig = 1; mysig < 33; mysig++) {
        if (signal(mysig, signal_handler) == SIG_ERR)
        {
            fprintf(mylog, "signal \"%s\" not installed.\n", signal_table[mysig]);
            printf("signal \"%s\" not installed.\n", signal_table[mysig]);
        }
        else
        {
            fprintf(mylog, "signal \"%s\" installed correctly.\n", signal_table[mysig]);
            printf("signal \"%s\" installed correctly.\n", signal_table[mysig]);
        }
    }

    fprintf(mylog, "\n-------------------------\n");
    fflush(mylog);

    while(go_on) {
        printf("counter: %d\n", counter++);
        sleep(1);
    }

    fclose(mylog);

    return 0;
}