ポインタの正体チェック

なんとなく heap と stack くらいは加えておきました。何か調べたわけでもないので適当。

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

extern char __executable_start;
extern char etext;
extern char __bss_start;
extern char end;

void print_where(void *p) {
    printf("%p: ", p);
    if (&__executable_start > p) {
        printf("i guess it's not pointer\n");
    }
    else if (&etext > p) {
        printf("it's in .text\n");
    }
    else if (&__bss_start > p) {
        printf("i guess it's data\n");
    }
    else if (&end > p) {
        printf("it's in .bss\n");
    }
    else if (sbrk(0) > p) {
        printf("it's heap\n");
    }
    else if (p > &p) {
        printf("it's stack\n");
    }
    else {
        printf("i guess it's ...\n");
    }
}

int global_variable;

int main(int argc, char *argv[]) {
    static int static_variable;

    print_where(&main);
    print_where(&print_where);
    print_where(&global_variable);
    print_where(&static_variable);
    print_where(&argc);
    print_where(malloc(1));
    print_where("hello");
    print_where(NULL);

    return 0;
}