tor-browser

tzselect.ksh (6880B)

---

#! /bin/ksh

# '@(#)tzselect.ksh	8.1'

# Ask the user about the time zone, and output the resulting TZ value to stdout.
# Interact with the user via stderr and stdin.

# Contributed by Paul Eggert.

# Porting notes:
#
# This script requires several features of the Korn shell.
# If your host lacks the Korn shell,
# you can use either of the following free programs instead:
#
#	<a href=ftp://ftp.gnu.org/pub/gnu/>
#	Bourne-Again shell (bash)
#	</a>
#
#	<a href=ftp://ftp.cs.mun.ca/pub/pdksh/pdksh.tar.gz>
#	Public domain ksh
#	</a>
#
# This script also uses several features of modern awk programs.
# If your host lacks awk, or has an old awk that does not conform to Posix.2,
# you can use either of the following free programs instead:
#
#	<a href=ftp://ftp.gnu.org/pub/gnu/>
#	GNU awk (gawk)
#	</a>
#
#	<a href=ftp://ftp.whidbey.net/pub/brennan/>
#	mawk
#	</a>


# Specify default values for environment variables if they are unset.
: ${AWK=awk}
: ${TZDIR=$(pwd)}

# Check for awk Posix compliance.
($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
[ $? = 123 ] || {
echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
exit 1
}

# Make sure the tables are readable.
TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
TZ_ZONE_TABLE=$TZDIR/zone.tab
for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
do
<$f || {
	echo >&2 "$0: time zone files are not set up correctly"
	exit 1
}
done

newline='
'
IFS=$newline


# Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
?*) PS3=
esac


# Begin the main loop.  We come back here if the user wants to retry.
while

echo >&2 'Please identify a location' \
	'so that time zone rules can be set correctly.'

continent=
country=
region=


# Ask the user for continent or ocean.

echo >&2 'Please select a continent or ocean.'

select continent in \
    Africa \
    Americas \
    Antarctica \
    'Arctic Ocean' \
    Asia \
    'Atlantic Ocean' \
    Australia \
    Europe \
    'Indian Ocean' \
    'Pacific Ocean' \
    'none - I want to specify the time zone using the Posix TZ format.'
do
    case $continent in
    '')
	echo >&2 'Please enter a number in range.';;
    ?*)
	case $continent in
	Americas) continent=America;;
	*' '*) continent=$(expr "$continent" : '\([^ ]*\)')
	esac
	break
    esac
done
case $continent in
'')
	exit 1;;
none)
	# Ask the user for a Posix TZ string.  Check that it conforms.
	while
		echo >&2 'Please enter the desired value' \
			'of the TZ environment variable.'
		echo >&2 'For example, GST-10 is a zone named GST' \
			'that is 10 hours ahead (east) of UTC.'
		read TZ
		$AWK -v TZ="$TZ" 'BEGIN {
			tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
			time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
			offset = "[-+]?" time
			date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
			datetime = "," date "(/" time ")?"
			tzpattern = "^(:.*|" tzname offset "(" tzname \
			  "(" offset ")?(" datetime datetime ")?)?)$"
			if (TZ ~ tzpattern) exit 1
			exit 0
		}'
	do
		echo >&2 "\`$TZ' is not a conforming" \
			'Posix time zone string.'
	done
	TZ_for_date=$TZ;;
*)
	# Get list of names of countries in the continent or ocean.
	countries=$($AWK -F'\t' \
		-v continent="$continent" \
		-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
	'
		/^#/ { next }
		$3 ~ ("^" continent "/") {
			if (!cc_seen[$1]++) cc_list[++ccs] = $1
		}
		END {
			while (getline <TZ_COUNTRY_TABLE) {
				if ($0 !~ /^#/) cc_name[$1] = $2
			}
			for (i = 1; i <= ccs; i++) {
				country = cc_list[i]
				if (cc_name[country]) {
				  country = cc_name[country]
				}
				print country
			}
		}
	' <$TZ_ZONE_TABLE | sort -f)


	# If there's more than one country, ask the user which one.
	case $countries in
	*"$newline"*)
		echo >&2 'Please select a country.'
		select country in $countries
		do
		    case $country in
		    '') echo >&2 'Please enter a number in range.';;
		    ?*) break
		    esac
		done

		case $country in
		'') exit 1
		esac;;
	*)
		country=$countries
	esac


	# Get list of names of time zone rule regions in the country.
	regions=$($AWK -F'\t' \
		-v country="$country" \
		-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
	'
		BEGIN {
			cc = country
			while (getline <TZ_COUNTRY_TABLE) {
				if ($0 !~ /^#/  &&  country == $2) {
					cc = $1
					break
				}
			}
		}
		$1 == cc { print $4 }
	' <$TZ_ZONE_TABLE)


	# If there's more than one region, ask the user which one.
	case $regions in
	*"$newline"*)
		echo >&2 'Please select one of the following' \
			'time zone regions.'
		select region in $regions
		do
			case $region in
			'') echo >&2 'Please enter a number in range.';;
			?*) break
			esac
		done
		case $region in
		'') exit 1
		esac;;
	*)
		region=$regions
	esac

	# Determine TZ from country and region.
	TZ=$($AWK -F'\t' \
		-v country="$country" \
		-v region="$region" \
		-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
	'
		BEGIN {
			cc = country
			while (getline <TZ_COUNTRY_TABLE) {
				if ($0 !~ /^#/  &&  country == $2) {
					cc = $1
					break
				}
			}
		}
		$1 == cc && $4 == region { print $3 }
	' <$TZ_ZONE_TABLE)

	# Make sure the corresponding zoneinfo file exists.
	TZ_for_date=$TZDIR/$TZ
	<$TZ_for_date || {
		echo >&2 "$0: time zone files are not set up correctly"
		exit 1
	}
esac


# Use the proposed TZ to output the current date relative to UTC.
# Loop until they agree in seconds.
# Give up after 8 unsuccessful tries.

extra_info=
for i in 1 2 3 4 5 6 7 8
do
	TZdate=$(LANG=C TZ="$TZ_for_date" date)
	UTdate=$(LANG=C TZ=UTC0 date)
	TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
	UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
	case $TZsec in
	$UTsec)
		extra_info="
Local time is now:	$TZdate.
Universal Time is now:	$UTdate."
		break
	esac
done


# Output TZ info and ask the user to confirm.

echo >&2 ""
echo >&2 "The following information has been given:"
echo >&2 ""
case $country+$region in
?*+?*)	echo >&2 "	$country$newline	$region";;
?*+)	echo >&2 "	$country";;
+)	echo >&2 "	TZ='$TZ'"
esac
echo >&2 ""
echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
echo >&2 "Is the above information OK?"

ok=
select ok in Yes No
do
    case $ok in
    '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
    ?*) break
    esac
done
case $ok in
'') exit 1;;
Yes) break
esac
do :
done

case $SHELL in
*csh) file=.login line="setenv TZ '$TZ'";;
*) file=.profile line="TZ='$TZ'; export TZ"
esac

echo >&2 "
You can make this change permanent for yourself by appending the line
$line
to the file '$file' in your home directory; then log out and log in again.

Here is that TZ value again, this time on standard output so that you
can use the $0 command in shell scripts:"

echo "$TZ"