memsearch.c

/*
  ∂ [src]: cc memmaps.c && ./a.out

Address of myVar: 0x7fff808cb864
Address of pointer: 0x7fff808cb878
Looks like 0x7fff808cb3b0->0x7fff808cb864 is a pointer to 0x7fff808cb864!
Looks like 0x7fff808cb770->0x7fff808cb864 is a pointer to 0x7fff808cb864!
Looks like 0x7fff808cb778->0x7fff808cb864 is a pointer to 0x7fff808cb864!
Looks like 0x7fff808cb828->0x7fff808cb864 is a pointer to 0x7fff808cb864!
Looks like 0x7fff808cb878->0x7fff808cb864 is a pointer to 0x7fff808cb864!

*/

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

void*
look_for_pointer(void* start, void* end, void* address) {
	void* i;

	for(i = start; i != end; i+=8) {
		if( *(void**)i == address ) {
			printf("Looks like %p->%p is a pointer to %p!\n", i, *(void**)i, address);
		}
	}

	return NULL;
}

int
main(void) {
	FILE* fp;
	char* line = NULL;
	size_t len = 0;
	ssize_t read;

	fp = fopen("/proc/self/maps", "r");
	if (fp == NULL)
	 exit(EXIT_FAILURE);

	int myVar = 100;
	int* pointer = &myVar;
	printf("Address of myVar: %p\n", &myVar);
	printf("Address of pointer: %p\n", &pointer);

	while ((read = getline(&line, &len, fp)) != -1) {
		long start, stop;
		char read, write;
		sscanf(line, "%16lx-%16lx %c%c", &start, &stop, &read, &write);
		if (read == 'r' && write == 'w') {
			look_for_pointer((void*)start, (void*)stop, &myVar);
		}
	}

	if (line)
		free(line);

	exit(EXIT_SUCCESS);
}