example of how to use readlink

xreadlink.c

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

#define xreadlink(f) _xreadlink(f, NULL, 128)

char *_xreadlink(const char *path, char *chunk, size_t len)
{
	char *ptr;
	ssize_t n = 0;

loop:
	if ((ptr = realloc(chunk, len)) == NULL) {
                if(chunk) chunk[n] = 0x0;
                return chunk;
        }

	n = readlink(path, ptr, len);

	if (n == -1) { free(ptr); ptr = NULL; }
	else if (n == len) { len <<= 1; goto loop; }
	else ptr[n] = 0x0;

	return ptr;
}

int main(int argc, char **argv)
{
	char *exe, buf[128];

	if (argv && argv[1]) {
		snprintf(buf, sizeof(buf), "/proc/%s/exe", argv[1]);
		exe = xreadlink(buf);
		printf("(%s) %s\n", argv[1], exe);
		free(exe);
	}

	return 0;
}