#include <stddef.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <err.h>

#define vectorof(T, m) offsetof(T, m), (offsetof(T, m) + sizeof (*(T *)0).m)
#define ss_vectorof(m) vectorof(struct sockaddr_storage, m)
#define sin_vectorof(m) vectorof(struct sockaddr_in, m)

#if !defined MUSL_PATCH
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>

#if !__APPLE__
#error exected Darwin
#endif

static void
ss_layout(void)
{
	printf(".ss_len:     %zu,%zu\n", ss_vectorof(ss_len));
	printf(".ss_family:  %zu,%zu\n", ss_vectorof(ss_family));
	printf(".__ss_pad1:  %zu,%zu\n", ss_vectorof(__ss_pad1));
	printf(".__ss_align: %zu,%zu\n", ss_vectorof(__ss_align));
	printf(".__ss_pad2:  %zu,%zu\n", ss_vectorof(__ss_pad2));
}
#else

typedef unsigned socklen_t;
typedef unsigned short sa_family_t;

#if MUSL_PATCH == 2
struct sockaddr_storage {
	sa_family_t ss_family;
	char __ss_padding[128-sizeof(long)-sizeof(sa_family_t)];
	unsigned long __ss_align;
};

static void
ss_layout(void)
{
	printf(".ss_family:    %zu,%zu\n", ss_vectorof(ss_family));
	printf(".__ss_padding: %zu,%zu\n", ss_vectorof(__ss_padding));
	printf(".__ss_align:   %zu,%zu\n", ss_vectorof(__ss_align));
}
#elif MUSL_PATCH == 1
struct sockaddr_storage {
	sa_family_t ss_family;
	char __ss_family_pad[sizeof(long)-sizeof(sa_family_t)];
	unsigned long __ss_align;
	char __ss_padding[128-2*sizeof(unsigned long)];
};

static void
ss_layout(void)
{
	printf(".ss_family:       %zu,%zu\n", ss_vectorof(ss_family));
	printf(".__ss_family_pad: %zu,%zu\n", ss_vectorof(__ss_family_pad));
	printf(".__ss_align:      %zu,%zu\n", ss_vectorof(__ss_align));
	printf(".__ss_padding:    %zu,%zu\n", ss_vectorof(__ss_padding));
}
#else
struct sockaddr_storage {
	sa_family_t ss_family;
	unsigned long __ss_align;
	char __ss_padding[128-2*sizeof(unsigned long)];
};

static void
ss_layout(void)
{
	printf(".ss_family:    %zu,%zu\n", ss_vectorof(ss_family));
	printf(".__ss_align:   %zu,%zu\n", ss_vectorof(__ss_align));
	printf(".__ss_padding: %zu,%zu\n", ss_vectorof(__ss_padding));
}
#endif
                                        
typedef uint16_t in_port_t;
typedef uint32_t in_addr_t;
struct in_addr { in_addr_t s_addr; };
struct sockaddr_in {
	sa_family_t sin_family;
	in_port_t sin_port;
	struct in_addr sin_addr;
	uint8_t sin_zero[8];
};
#define INADDR_LOOPBACK UINT32_C(0x7f000001)
#define AF_INET 2
#undef htonl
#undef htons
#undef ntohl
#undef ntohs

uint32_t htonl(uint32_t);
uint16_t htons(uint16_t);
uint32_t ntohl(uint32_t);
uint16_t ntohs(uint16_t);
#endif

static void
sin_layout(void)
{
	printf(".sin_family: %zu,%zu\n", sin_vectorof(sin_family));
	printf(".sin_port:   %zu,%zu\n", sin_vectorof(sin_port));
	printf(".sin_addr:   %zu,%zu\n", sin_vectorof(sin_addr));
}

struct dbg_listener {
	struct sockaddr_storage addr;
};

int
main(void)
{
	struct dbg_listener *l;
	struct sockaddr_storage ss, *ss2, ss3;

	ss_layout();
	sin_layout();

	memset(&ss3, 0, sizeof ss3);
	ss3.ss_family = AF_INET;
	((struct sockaddr_in *)&ss3)->sin_addr.s_addr = htonl(INADDR_LOOPBACK);

	ss2 = &ss3;
	ss = *ss2;

	l = calloc(1, sizeof *l);
	l->addr = ss;

	printf("0x%.8x (%s)\n",
	    ntohl(((struct sockaddr_in *)(&l->addr))->sin_addr.s_addr),
	    (ntohl(((struct sockaddr_in *)(&l->addr))->sin_addr.s_addr) == INADDR_LOOPBACK)?
	        "OKAY" : "FAIL");

	return 0;
}