panic.c

#include <defs.h>
#include <stdio.h>
#include <intr.h>
#include <kmonitor.h>

static bool is_panic = 0;

/* *
 * __panic - __panic is called on unresolvable fatal errors. it prints
 * "panic: 'message'", and then enters the kernel monitor.
 * */
void
__panic(const char *file, int line, const char *fmt, ...) {
    if (is_panic) {
        goto panic_dead;
    }
    is_panic = 1;

    // print the 'message'
    va_list ap;
    va_start(ap, fmt);
    cprintf("kernel panic at %s:%d:\n    ", file, line);
    vcprintf(fmt, ap);
    cprintf("\n");

    cprintf("stack trackback:\n");
    print_stackframe();

    va_end(ap);

panic_dead:
    intr_disable();
    while (1) {
        kmonitor(NULL);
    }
}

/* __warn - like panic, but don't */
void
__warn(const char *file, int line, const char *fmt, ...) {
    va_list ap;
    va_start(ap, fmt);
    cprintf("kernel warning at %s:%d:\n    ", file, line);
    vcprintf(fmt, ap);
    cprintf("\n");
    va_end(ap);
}

bool
is_kernel_panic(void) {
    return is_panic;
}