ex_signals.c

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/*
 * Nilorea Library
 * Copyright (C) 2005-2026 Castagnier Mickael
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <stdbool.h>
#include <errno.h>
#include <signal.h>
#include <assert.h>
 
#include "nilorea/n_signals.h"
#include "nilorea/n_log.h"
 
#include <libgen.h>
 
int divide_by_zero(void);
void cause_segfault(void);
int stack_overflow(void);
void infinite_loop(void);
void illegal_instruction(void);
void cause_calamity(void);
 
char* progname = NULL;
 
int main(int argc, char* argv[]) {
    (void)argc;
    progname = argv[0];
 
    // set_log_file( "ex_signals.log" );
    set_log_level(LOG_DEBUG);
    set_log_level(LOG_STDERR);
    // set_log_level( LOG_FILE );
 
    n_log(LOG_DEBUG, "set_signal_handler");
    set_signal_handler(basename(progname));
 
    n_log(LOG_DEBUG, "cause_calamity");
    cause_calamity();
 
    return 0;
}
 
void cause_calamity(void) {
    /* uncomment one of the following error conditions to cause a calamity of
       your choosing! */
    stack_overflow();
    (void)divide_by_zero();
    cause_segfault();
    assert(false);
    infinite_loop();
    illegal_instruction();
}
 
int divide_by_zero(void) {
    int a = 1;
    int b = 0;
    return a / b;
}
 
void cause_segfault(void) {
    int* p = (int*)0x12345678;
    *p = 0;
}
 
// that function was made to generate an error. Temporary disabling infinite recursion detection
#pragma GCC diagnostic push
#if defined(__GNUC__) && (__GNUC__ >= 12)
#pragma GCC diagnostic ignored "-Winfinite-recursion"
#endif
int stack_overflow(void) {
    int foo = 0;
    (void)foo;
    foo = stack_overflow();
    return rand() % 1000;
}
#pragma GCC diagnostic pop
 
/* break out with ctrl+c to test SIGINT handling */
void infinite_loop(void) {
    int a = 1;
    int b = 1;
    int c = 1;
    while (a == 1) {
        b = c;
        c = a;
        a = b;
    }
}
 
void illegal_instruction(void) {
    /* I couldn't find an easy way to cause this one, so I'm cheating */
    raise(SIGILL);
}