xref: /freebsd-11.0-release/usr.sbin/tzsetup/tzsetup.c

/*
 * Copyright 1996 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Second attempt at a `tzmenu' program, using the separate description
 * files provided in newer tzdata releases.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: head/usr.sbin/tzsetup/tzsetup.c 198267 2009-10-20 06:54:31Z edwin $");

#include <dialog.h>
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <sys/fcntl.h>
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/stat.h>

#define	_PATH_ZONETAB		"/usr/share/zoneinfo/zone.tab"
#define	_PATH_ISO3166		"/usr/share/misc/iso3166"
#define	_PATH_ZONEINFO		"/usr/share/zoneinfo"
#define	_PATH_LOCALTIME		"/etc/localtime"
#define	_PATH_DB		"/var/db/zoneinfo"
#define	_PATH_WALL_CMOS_CLOCK	"/etc/wall_cmos_clock"

static int reallydoit = 1;
static int reinstall = 0;

static void	usage(void);
static int	continent_country_menu(dialogMenuItem *);
static int	set_zone_multi(dialogMenuItem *);
static int	set_zone_whole_country(dialogMenuItem *);
static int	set_zone_menu(dialogMenuItem *);

struct continent {
	dialogMenuItem *menu;
	int		nitems;
	int		ch;
	int		sc;
};

static struct continent	africa, america, antarctica, arctic, asia, atlantic;
static struct continent	australia, europe, indian, pacific;

static struct continent_names {
	const char	*name;
	struct continent *continent;
} continent_names[] = {
	{ "Africa",	&africa },
	{ "America",	&america },
	{ "Antarctica",	&antarctica },
	{ "Arctic",	&arctic },
	{ "Asia",	&asia },
	{ "Atlantic",	&atlantic },
	{ "Australia",	&australia },
	{ "Europe",	&europe },
	{ "Indian",	&indian },
	{ "Pacific",	&pacific }
};

static struct continent_items {
	char		prompt[2];
	char		title[30];
} continent_items[] = {
	{ "1",	"Africa" },
	{ "2",	"America -- North and South" },
	{ "3",	"Antarctica" },
	{ "4",	"Arctic Ocean" },
	{ "5",	"Asia" },
	{ "6",	"Atlantic Ocean" },
	{ "7",	"Australia" },
	{ "8",	"Europe" },
	{ "9",	"Indian Ocean" },
	{ "0",	"Pacific Ocean" }
};

#define	NCONTINENTS	\
    (int)((sizeof(continent_items)) / (sizeof(continent_items[0])))
static dialogMenuItem continents[NCONTINENTS];

#define	OCEANP(x)	((x) == 3 || (x) == 5 || (x) == 8 || (x) == 9)

static int
continent_country_menu(dialogMenuItem *continent)
{
	char		title[64], prompt[64];
	struct continent *contp = continent->data;
	int		isocean = OCEANP(continent - continents);
	int		menulen;
	int		rv;

	/* Short cut -- if there's only one country, don't post a menu. */
	if (contp->nitems == 1)
		return (contp->menu[0].fire(&contp->menu[0]));

	/* It's amazing how much good grammar really matters... */
	if (!isocean) {
		snprintf(title, sizeof(title), "Countries in %s",
		    continent->title);
		snprintf(prompt, sizeof(prompt), "Select a country or region");
	} else {
		snprintf(title, sizeof(title), "Islands and groups in the %s",
		    continent->title);
		snprintf(prompt, sizeof(prompt), "Select an island or group");
	}

	menulen = contp->nitems < 16 ? contp->nitems : 16;
	rv = dialog_menu(title, prompt, -1, -1, menulen, -contp->nitems,
	    contp->menu, 0, &contp->ch, &contp->sc);
	if (rv == 0)
		return (DITEM_LEAVE_MENU);
	return (DITEM_RECREATE);
}

static struct continent *
find_continent(const char *name)
{
	int		i;

	for (i = 0; i < NCONTINENTS; i++)
		if (strcmp(name, continent_names[i].name) == 0)
			return (continent_names[i].continent);
	return (0);
}

struct country {
	char		*name;
	char		*tlc;
	int		nzones;
	char		*filename;	/* use iff nzones < 0 */
	struct continent *continent;	/* use iff nzones < 0 */
	TAILQ_HEAD(, zone) zones;	/* use iff nzones > 0 */
	dialogMenuItem	*submenu;	/* use iff nzones > 0 */
};

struct zone {
	TAILQ_ENTRY(zone) link;
	char		*descr;
	char		*filename;
	struct continent *continent;
};

/*
 * This is the easiest organization... we use ISO 3166 country codes,
 * of the two-letter variety, so we just size this array to suit.
 * Beats worrying about dynamic allocation.
 */
#define	NCOUNTRIES	(26 * 26)
static struct country countries[NCOUNTRIES];

#define	CODE2INT(s)	((s[0] - 'A') * 26 + (s[1] - 'A'))

/*
 * Read the ISO 3166 country code database in _PATH_ISO3166
 * (/usr/share/misc/iso3166).  On error, exit via err(3).
 */
static void
read_iso3166_table(void)
{
	FILE		*fp;
	struct country	*cp;
	size_t		len;
	char		*s, *t, *name;
	int		lineno;

	fp = fopen(_PATH_ISO3166, "r");
	if (!fp)
		err(1, _PATH_ISO3166);
	lineno = 0;

	while ((s = fgetln(fp, &len)) != 0) {
		lineno++;
		if (s[len - 1] != '\n')
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);
		s[len - 1] = '\0';
		if (s[0] == '#' || strspn(s, " \t") == len - 1)
			continue;

		/* Isolate the two-letter code. */
		t = strsep(&s, "\t");
		if (t == 0 || strlen(t) != 2)
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);
		if (t[0] < 'A' || t[0] > 'Z' || t[1] < 'A' || t[1] > 'Z')
			errx(1, _PATH_ISO3166 ":%d: invalid code `%s'",
			    lineno, t);

		/* Now skip past the three-letter and numeric codes. */
		name = strsep(&s, "\t");	/* 3-let */
		if (name == 0 || strlen(name) != 3)
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);
		name = strsep(&s, "\t");	/* numeric */
		if (name == 0 || strlen(name) != 3)
			errx(1, _PATH_ISO3166 ":%d: invalid format", lineno);

		name = s;

		cp = &countries[CODE2INT(t)];
		if (cp->name)
			errx(1, _PATH_ISO3166
			    ":%d: country code `%s' multiply defined: %s",
			    lineno, t, cp->name);
		cp->name = strdup(name);
		if (cp->name == NULL)
			errx(1, "malloc failed");
		cp->tlc = strdup(t);
		if (cp->tlc == NULL)
			errx(1, "malloc failed");
	}

	fclose(fp);
}

static void
add_zone_to_country(int lineno, const char *tlc, const char *descr,
    const char *file, struct continent *cont)
{
	struct zone	*zp;
	struct country	*cp;

	if (tlc[0] < 'A' || tlc[0] > 'Z' || tlc[1] < 'A' || tlc[1] > 'Z')
		errx(1, _PATH_ZONETAB ":%d: country code `%s' invalid",
		    lineno, tlc);

	cp = &countries[CODE2INT(tlc)];
	if (cp->name == 0)
		errx(1, _PATH_ZONETAB ":%d: country code `%s' unknown",
		    lineno, tlc);

	if (descr) {
		if (cp->nzones < 0)
			errx(1, _PATH_ZONETAB
			    ":%d: conflicting zone definition", lineno);

		zp = malloc(sizeof(*zp));
		if (zp == 0)
			errx(1, "malloc(%zu)", sizeof(*zp));

		if (cp->nzones == 0)
			TAILQ_INIT(&cp->zones);

		zp->descr = strdup(descr);
		if (zp->descr == NULL)
			errx(1, "malloc failed");
		zp->filename = strdup(file);
		if (zp->filename == NULL)
			errx(1, "malloc failed");
		zp->continent = cont;
		TAILQ_INSERT_TAIL(&cp->zones, zp, link);
		cp->nzones++;
	} else {
		if (cp->nzones > 0)
			errx(1, _PATH_ZONETAB
			    ":%d: zone must have description", lineno);
		if (cp->nzones < 0)
			errx(1, _PATH_ZONETAB
			    ":%d: zone multiply defined", lineno);
		cp->nzones = -1;
		cp->filename = strdup(file);
		if (cp->filename == NULL)
			errx(1, "malloc failed");
		cp->continent = cont;
	}
}

/*
 * This comparison function intentionally sorts all of the null-named
 * ``countries''---i.e., the codes that don't correspond to a real
 * country---to the end.  Everything else is lexical by country name.
 */
static int
compare_countries(const void *xa, const void *xb)
{
	const struct country *a = xa, *b = xb;

	if (a->name == 0 && b->name == 0)
		return (0);
	if (a->name == 0 && b->name != 0)
		return (1);
	if (b->name == 0)
		return (-1);

	return (strcmp(a->name, b->name));
}

/*
 * This must be done AFTER all zone descriptions are read, since it breaks
 * CODE2INT().
 */
static void
sort_countries(void)
{

	qsort(countries, NCOUNTRIES, sizeof(countries[0]), compare_countries);
}

static void
read_zones(void)
{
	char		contbuf[16];
	FILE		*fp;
	struct continent *cont;
	size_t		len;
	char		*line, *tlc, *coord, *file, *descr, *p;
	int		lineno;

	fp = fopen(_PATH_ZONETAB, "r");
	if (!fp)
		err(1, _PATH_ZONETAB);
	lineno = 0;

	while ((line = fgetln(fp, &len)) != 0) {
		lineno++;
		if (line[len - 1] != '\n')
			errx(1, _PATH_ZONETAB ":%d: invalid format", lineno);
		line[len - 1] = '\0';
		if (line[0] == '#')
			continue;

		tlc = strsep(&line, "\t");
		if (strlen(tlc) != 2)
			errx(1, _PATH_ZONETAB ":%d: invalid country code `%s'",
			    lineno, tlc);
		coord = strsep(&line, "\t");
		file = strsep(&line, "\t");
		p = strchr(file, '/');
		if (p == 0)
			errx(1, _PATH_ZONETAB ":%d: invalid zone name `%s'",
			    lineno, file);
		contbuf[0] = '\0';
		strncat(contbuf, file, p - file);
		cont = find_continent(contbuf);
		if (!cont)
			errx(1, _PATH_ZONETAB ":%d: invalid region `%s'",
			    lineno, contbuf);

		descr = (line != NULL && *line != '\0') ? line : NULL;

		add_zone_to_country(lineno, tlc, descr, file, cont);
	}
	fclose(fp);
}

static void
make_menus(void)
{
	struct country	*cp;
	struct zone	*zp, *zp2;
	struct continent *cont;
	dialogMenuItem	*dmi;
	int		i;

	/*
	 * First, count up all the countries in each continent/ocean.
	 * Be careful to count those countries which have multiple zones
	 * only once for each.  NB: some countries are in multiple
	 * continents/oceans.
	 */
	for (cp = countries; cp->name; cp++) {
		if (cp->nzones == 0)
			continue;
		if (cp->nzones < 0) {
			cp->continent->nitems++;
		} else {
			TAILQ_FOREACH(zp, &cp->zones, link) {
				cont = zp->continent;
				for (zp2 = TAILQ_FIRST(&cp->zones);
				    zp2->continent != cont;
				    zp2 = TAILQ_NEXT(zp2, link))
					;
				if (zp2 == zp)
					zp->continent->nitems++;
			}
		}
	}

	/*
	 * Now allocate memory for the country menus and initialize
	 * continent menus.  We set nitems back to zero so that we can
	 * use it for counting again when we actually build the menus.
	 */
	memset(continents, 0, sizeof(continents));
	for (i = 0; i < NCONTINENTS; i++) {
		continent_names[i].continent->menu =
		    malloc(sizeof(dialogMenuItem) *
		    continent_names[i].continent->nitems);
		if (continent_names[i].continent->menu == 0)
			errx(1, "malloc for continent menu");
		continent_names[i].continent->nitems = 0;
		continents[i].prompt = continent_items[i].prompt;
		continents[i].title = continent_items[i].title;
		continents[i].fire = continent_country_menu;
		continents[i].data = continent_names[i].continent;
	}

	/*
	 * Now that memory is allocated, create the menu items for
	 * each continent.  For multiple-zone countries, also create
	 * the country's zone submenu.
	 */
	for (cp = countries; cp->name; cp++) {
		if (cp->nzones == 0)
			continue;
		if (cp->nzones < 0) {
			dmi = &cp->continent->menu[cp->continent->nitems];
			memset(dmi, 0, sizeof(*dmi));
			asprintf(&dmi->prompt, "%d", ++cp->continent->nitems);
			dmi->title = cp->name;
			dmi->checked = 0;
			dmi->fire = set_zone_whole_country;
			dmi->selected = 0;
			dmi->data = cp;
		} else {
			cp->submenu = malloc(cp->nzones * sizeof(*dmi));
			if (cp->submenu == 0)
				errx(1, "malloc for submenu");
			cp->nzones = 0;
			TAILQ_FOREACH(zp, &cp->zones, link) {
				cont = zp->continent;
				dmi = &cp->submenu[cp->nzones];
				memset(dmi, 0, sizeof(*dmi));
				asprintf(&dmi->prompt, "%d", ++cp->nzones);
				dmi->title = zp->descr;
				dmi->checked = 0;
				dmi->fire = set_zone_multi;
				dmi->selected = 0;
				dmi->data = zp;

				for (zp2 = TAILQ_FIRST(&cp->zones);
				    zp2->continent != cont;
				    zp2 = TAILQ_NEXT(zp2, link))
					;
				if (zp2 != zp)
					continue;

				dmi = &cont->menu[cont->nitems];
				memset(dmi, 0, sizeof(*dmi));
				asprintf(&dmi->prompt, "%d", ++cont->nitems);
				dmi->title = cp->name;
				dmi->checked = 0;
				dmi->fire = set_zone_menu;
				dmi->selected = 0;
				dmi->data = cp;
			}
		}
	}
}

static int
set_zone_menu(dialogMenuItem *dmi)
{
	char		title[64], prompt[64];
	struct country	*cp = dmi->data;
	int		menulen;
	int		rv;

	snprintf(title, sizeof(title), "%s Time Zones", cp->name);
	snprintf(prompt, sizeof(prompt),
	    "Select a zone which observes the same time as your locality.");
	menulen = cp->nzones < 16 ? cp->nzones : 16;
	rv = dialog_menu(title, prompt, -1, -1, menulen, -cp->nzones,
	    cp->submenu, 0, 0, 0);
	if (rv != 0)
		return (DITEM_RECREATE);
	return (DITEM_LEAVE_MENU);
}

static int
install_zone_file(const char *filename, int usedialog)
{
	char		buf[1024];
	char		title[64], prompt[64];
	struct stat	sb;
	ssize_t		len;
	int		fd1, fd2, copymode;
	FILE		*f;

	if (lstat(_PATH_LOCALTIME, &sb) < 0) {
		/* Nothing there yet... */
		copymode = 1;
	} else if (S_ISLNK(sb.st_mode))
		copymode = 0;
	else
		copymode = 1;

#ifdef VERBOSE
	if (copymode)
		snprintf(prompt, sizeof(prompt),
		    "Copying %s to " _PATH_LOCALTIME, filename);
	else
		snprintf(prompt, sizeof(prompt),
		    "Creating symbolic link " _PATH_LOCALTIME " to %s",
		    filename);
	if (usedialog)
		dialog_notify(prompt);
	else
		fprintf(stderr, "%s\n", prompt);
#endif

	if (reallydoit) {
		if (copymode) {
			fd1 = open(filename, O_RDONLY, 0);
			if (fd1 < 0) {
				snprintf(title, sizeof(title), "Error");
				snprintf(prompt, sizeof(prompt),
				    "Could not open %s: %s", filename,
				    strerror(errno));
				if (usedialog)
					dialog_mesgbox(title, prompt, 8, 72);
				else
					fprintf(stderr, "%s\n", prompt);
				return (DITEM_FAILURE | DITEM_RECREATE);
			}

			unlink(_PATH_LOCALTIME);
			fd2 = open(_PATH_LOCALTIME, O_CREAT | O_EXCL | O_WRONLY,
			    S_IRUSR | S_IRGRP | S_IROTH);
			if (fd2 < 0) {
				snprintf(title, sizeof(title), "Error");
				snprintf(prompt, sizeof(prompt),
				    "Could not open " _PATH_LOCALTIME ": %s",
				    strerror(errno));
				if (usedialog)
					dialog_mesgbox(title, prompt, 8, 72);
				else
					fprintf(stderr, "%s\n", prompt);
				return (DITEM_FAILURE | DITEM_RECREATE);
			}

			while ((len = read(fd1, buf, sizeof(buf))) > 0)
				len = write(fd2, buf, len);

			if (len == -1) {
				snprintf(title, sizeof(title), "Error");
				snprintf(prompt, sizeof(prompt),
				    "Error copying %s to " _PATH_LOCALTIME
				    ": %s", filename, strerror(errno));
				if (usedialog)
					dialog_mesgbox(title, prompt, 8, 72);
				else
					fprintf(stderr, "%s\n", prompt);
				/* Better to leave none than a corrupt one. */
				unlink(_PATH_LOCALTIME);
				return (DITEM_FAILURE | DITEM_RECREATE);
			}
			close(fd1);
			close(fd2);
		} else {
			if (access(filename, R_OK) != 0) {
				snprintf(title, sizeof(title), "Error");
				snprintf(prompt, sizeof(prompt),
				    "Cannot access %s: %s", filename,
				    strerror(errno));
				if (usedialog)
					dialog_mesgbox(title, prompt, 8, 72);
				else
					fprintf(stderr, "%s\n", prompt);
				return (DITEM_FAILURE | DITEM_RECREATE);
			}
			unlink(_PATH_LOCALTIME);
			if (symlink(filename, _PATH_LOCALTIME) < 0) {
				snprintf(title, sizeof(title), "Error");
				snprintf(prompt, sizeof(prompt),
				    "Cannot create symbolic link "
				    _PATH_LOCALTIME " to %s: %s", filename,
				    strerror(errno));
				if (usedialog)
					dialog_mesgbox(title, prompt, 8, 72);
				else
					fprintf(stderr, "%s\n", prompt);
				return (DITEM_FAILURE | DITEM_RECREATE);
			}
		}
	}

#ifdef VERBOSE
	snprintf(title, sizeof(title), "Done");
	if (copymode)
		snprintf(prompt, sizeof(prompt),
		    "Copied timezone file from %s to " _PATH_LOCALTIME,
		    filename);
	else
		snprintf(prompt, sizeof(prompt), "Created symbolic link from "
		    _PATH_LOCALTIME " to %s", filename);
	if (usedialog)
		dialog_mesgbox(title, prompt, 8, 72);
	else
		fprintf(stderr, "%s\n", prompt);
#endif

	/* Save knowledge for later */
	if ((f = fopen(_PATH_DB, "w")) != NULL) {
		fprintf(f, "%s\n", filename + strlen(_PATH_ZONEINFO) + 1);
		fclose(f);
	}

	return (DITEM_LEAVE_MENU);
}

static int
confirm_zone(const char *filename)
{
	char		title[64], prompt[64];
	time_t		t = time(0);
	struct tm	*tm;
	int		rv;

	setenv("TZ", filename, 1);
	tzset();
	tm = localtime(&t);

	snprintf(title, sizeof(title), "Confirmation");
	snprintf(prompt, sizeof(prompt),
	    "Does the abbreviation `%s' look reasonable?", tm->tm_zone);
	rv = !dialog_yesno(title, prompt, 5, 72);
	return (rv);
}

static int
set_zone_multi(dialogMenuItem *dmi)
{
	struct zone	*zp = dmi->data;
	char		*fn;
	int		rv;

	if (!confirm_zone(zp->filename))
		return (DITEM_FAILURE | DITEM_RECREATE);

	asprintf(&fn, "%s/%s", _PATH_ZONEINFO, zp->filename);
	rv = install_zone_file(fn, 1);
	free(fn);
	return (rv);
}

static int
set_zone_whole_country(dialogMenuItem *dmi)
{
	struct country	*cp = dmi->data;
	char		*fn;
	int		rv;

	if (!confirm_zone(cp->filename))
		return (DITEM_FAILURE | DITEM_RECREATE);

	asprintf(&fn, "%s/%s", _PATH_ZONEINFO, cp->filename);
	rv = install_zone_file(fn, 1);
	free(fn);
	return (rv);
}

static void
usage(void)
{

	fprintf(stderr, "usage: tzsetup [-nrs] [zoneinfo file]\n");
	exit(1);
}

#if defined(__sparc64__)
#define	DIALOG_UTC	dialog_yesno
#else
#define	DIALOG_UTC	dialog_noyes
#endif

int
main(int argc, char **argv)
{
	char		title[64], prompt[128];
	int		c, fd, rv, skiputc;

	skiputc = 0;
	while ((c = getopt(argc, argv, "nrs")) != -1) {
		switch(c) {
		case 'n':
			reallydoit = 0;
			break;
		case 'r':
			reinstall = 1;
			break;
		case 's':
			skiputc = 1;
			break;
		default:
			usage();
		}
	}

	if (argc - optind > 1)
		usage();

	/* Override the user-supplied umask. */
	(void)umask(S_IWGRP | S_IWOTH);

	read_iso3166_table();
	read_zones();
	sort_countries();
	make_menus();

	if (reinstall == 1) {
		FILE *f;
		char zonefile[MAXPATHLEN];

		sprintf(zonefile, "%s/", _PATH_ZONEINFO);
		if ((f = fopen(_PATH_DB, "r")) != NULL) {
			if (fgets(zonefile + strlen(zonefile),
			    sizeof(zonefile) - strlen(zonefile), f) != NULL) {
				zonefile[sizeof(zonefile) - 1] = 0;
				if (strlen(zonefile) > 0) {
					zonefile[strlen(zonefile) - 1] = 0;
					rv = install_zone_file(zonefile, 0);
					exit(rv & ~DITEM_LEAVE_MENU);
				}
				errx(1, "Error reading %s.\n", _PATH_DB);
			}
			fclose(f);
			errx(1,
			    "Unable to determine earlier installed zoneinfo "
			    "file. Check %s", _PATH_DB);
		}
		errx(1, "Cannot open %s for reading. Does it exist?", _PATH_DB);
	}

	init_dialog();
	if (skiputc == 0) {
		snprintf(title, sizeof(title),
		    "Select local or UTC (Greenwich Mean Time) clock");
		snprintf(prompt, sizeof(prompt),
		    "Is this machine's CMOS clock set to UTC?  "
		    "If it is set to local time,\n"
		    "or you don't know, please choose NO here!");
		if (!DIALOG_UTC(title, prompt, 7, 72)) {
			if (reallydoit)
				unlink(_PATH_WALL_CMOS_CLOCK);
		} else {
			if (reallydoit) {
				fd = open(_PATH_WALL_CMOS_CLOCK,
				    O_WRONLY | O_CREAT | O_TRUNC,
				    S_IRUSR | S_IRGRP | S_IROTH);
				if (fd < 0) {
					end_dialog();
					err(1, "create %s",
					    _PATH_WALL_CMOS_CLOCK);
				}
				close(fd);
			}
		}
		dialog_clear_norefresh();
	}
	if (optind == argc - 1) {
		snprintf(title, sizeof(title), "Default timezone provided");
		snprintf(prompt, sizeof(prompt),
		    "\nUse the default `%s' zone?", argv[optind]);
		if (!dialog_yesno(title, prompt, 7, 72)) {
			rv = install_zone_file(argv[optind], 1);
			dialog_clear();
			end_dialog();
			exit(rv & ~DITEM_LEAVE_MENU);
		}
		dialog_clear_norefresh();
	}
	snprintf(title, sizeof(title), "Time Zone Selector");
	snprintf(prompt, sizeof(prompt), "Select a region");
	dialog_menu(title, prompt, -1, -1, NCONTINENTS, -NCONTINENTS,
	    continents, 0, NULL, NULL);

	dialog_clear();
	end_dialog();
	return (0);
}