#define _GNU_SOURCE

#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <error.h>
#include <errno.h>
#include <dlfcn.h>

#include "vers.h"

static void *
get_func (const char *symbol, const char *version)
{
	void   *addr;

	addr = dlvsym (RTLD_NEXT, symbol, version);
#ifdef DEBUG
	fprintf (stderr, "dlvsym (RTLD_NEXT, %s, %s) = %p\n",
		symbol, version, addr);
#endif
	if (!addr)
		error (1, errno, "dlvsym: %s@@%s", symbol, version);
	return addr;
}

typedef int (*chown_fptr) (const char *, uid_t, gid_t);

int
chown (const char *path, uid_t owner, gid_t group)
{
	if (getuid ())
	{
		static chown_fptr func = 0;

		if (!func)
			func = get_func ("chown", chown_vers);
		return func (path, owner, group);
	}
	return 0;
}

typedef int (*lchown_fptr) (const char *, uid_t, gid_t);

int
lchown (const char *path, uid_t owner, gid_t group)
{
	if (getuid ())
	{
		static lchown_fptr func = 0;

		if (!func)
			func = get_func ("lchown", lchown_vers);
		return func (path, owner, group);
	}
	return 0;
}

typedef int (*fchown_fptr) (int, uid_t, gid_t);

int
fchown (int fd, uid_t owner, gid_t group)
{
	if (getuid ())
	{
		static fchown_fptr func = 0;

		if (!func)
			func = get_func ("fchown", fchown_vers);
		return func (fd, owner, group);
	}
	return 0;
}

typedef int (*chmod_fptr) (const char *, mode_t);

int
chmod (const char *path, mode_t mode)
{
	if (getuid ())
	{
		static chmod_fptr func = 0;

		if (!func)
			func = get_func ("chmod", chmod_vers);
		return func (path, mode);
	}
	return 0;
}

typedef int (*fchmod_fptr) (int, mode_t);

int
fchmod (int fildes, mode_t mode)
{
	if (getuid ())
	{
		static fchmod_fptr func = 0;

		if (!func)
			func = get_func ("fchmod", chmod_vers);
		return func (fildes, mode);
	}
	return 0;
}