#ifndef __sun__
#include <err.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#ifdef __APPLE__
#define u_int	unsigned int
#endif

#define	MFLAG	0x01
#define	NFLAG	0x02
#define	PFLAG	0x04
#define	RFLAG	0x08
#define	SFLAG	0x10
#define	VFLAG	0x20
#define	IFLAG	0x40
#define	UFLAG	0x80

static void print_uname(u_int);
static void usage(void);

static const char *sysname  = "@OPSYS@";
static const char *arch     = "@ARCH@";
static const char *platform = "@PLATFORM@";
static const char *release  = "@RELEASE@";
static const char *uservers = "@USERVER@";
static const char *ident    = "GENERIC";
static const char *version  = "@OPSYS@ @RELEASE@ #0 Sat Jul 29 09:00:00 CDT 2017 root@octavia.unreal.systems:/usr/obj/usr/src/sys/GENERIC";
static const char *hostname = "octavia.unreal.systems";
static int space;

int
main(int argc, char *argv[])
{
	u_int flags;
	int ch;

	flags = 0;

	while ((ch = getopt(argc, argv, "aimnoprsUv")) != -1)
		switch(ch) {
		case 'a':
			flags |= (MFLAG | NFLAG | RFLAG | SFLAG | VFLAG);
			break;
		case 'i':
			flags |= IFLAG;
			break;
		case 'm':
			flags |= MFLAG;
			break;
		case 'n':
			flags |= NFLAG;
			break;
		case 'p':
			flags |= PFLAG;
			break;
		case 'r':
			flags |= RFLAG;
			break;
		case 's':
		case 'o':
			flags |= SFLAG;
			break;
		case 'U':
			flags |= UFLAG;
			break;
		case 'v':
			flags |= VFLAG;
			break;
		case '?':
		default:
			usage();
		}

	argc -= optind;
	argv += optind;

	if (argc)
		usage();

	if (!flags)
		flags |= SFLAG;

	print_uname(flags);
	exit(0);
}

#define	PRINT_FLAG(flags,flag,var)		\
	if ((flags & flag) == flag) {		\
		if (space)			\
			printf(" ");		\
		else				\
			space++;		\
		printf("%s", var);		\
	}

static void
print_uname(u_int flags)
{
	PRINT_FLAG(flags, SFLAG, sysname);
	PRINT_FLAG(flags, NFLAG, hostname);
	PRINT_FLAG(flags, RFLAG, release);
	PRINT_FLAG(flags, VFLAG, version);
	PRINT_FLAG(flags, MFLAG, platform);
	PRINT_FLAG(flags, PFLAG, arch);
	PRINT_FLAG(flags, IFLAG, ident);
	PRINT_FLAG(flags, UFLAG, uservers);
	printf("\n");
}

static void
usage(void)
{
	fprintf(stderr, "usage: uname [-aimnoprsUv]\n");
	exit(1);
}