lib/libc/time/tzselect.ksh

   1 #! /bin/ksh
   2 #
   3 #       $NetBSD: tzselect.ksh,v 1.7 2012/08/09 12:38:26 christos Exp $
   4 #
   5 VERSION=see_Makefile
   6
   7 # Ask the user about the time zone, and output the resulting TZ value to stdout.
   8 # Interact with the user via stderr and stdin.
   9
  10 # Contributed by Paul Eggert.
  11
  12 # Porting notes:
  13 #
  14 # This script requires several features of the Korn shell.
  15 # If your host lacks the Korn shell,
  16 # you can use either of the following free programs instead:
  17 #
  18 #       <a href=ftp://ftp.gnu.org/pub/gnu/>
  19 #       Bourne-Again shell (bash)
  20 #       </a>
  21 #
  22 #       <a href=ftp://ftp.cs.mun.ca/pub/pdksh/pdksh.tar.gz>
  23 #       Public domain ksh
  24 #       </a>
  25 #
  26 # This script also uses several features of modern awk programs.
  27 # If your host lacks awk, or has an old awk that does not conform to Posix.2,
  28 # you can use either of the following free programs instead:
  29 #
  30 #       <a href=ftp://ftp.gnu.org/pub/gnu/>
  31 #       GNU awk (gawk)
  32 #       </a>
  33 #
  34 #       <a href=ftp://ftp.whidbey.net/pub/brennan/>
  35 #       mawk
  36 #       </a>
  37
  38
  39 # Specify default values for environment variables if they are unset.
  40 : ${AWK=awk}
  41 : ${TZDIR=$(pwd)}
  42
  43 # Check for awk Posix compliance.
  44 ($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
  45 [ $? = 123 ] || {
  46         echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
  47         exit 1
  48 }
  49
  50 if [ "$1" = "--help" ]; then
  51     cat <<EOF
  52 Usage: tzselect
  53 Select a time zone interactively.
  54
  55 Report bugs to tz@elsie.nci.nih.gov.
  56 EOF
  57     exit 0
  58 elif [ "$1" = "--version" ]; then
  59     cat <<EOF
  60 tzselect $TZVERSION
  61 EOF
  62     exit 0
  63 fi
  64
  65 # Make sure the tables are readable.
  66 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
  67 TZ_ZONE_TABLE=$TZDIR/zone.tab
  68 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
  69 do
  70         <$f || {
  71                 echo >&2 "$0: time zone files are not set up correctly"
  72                 exit 1
  73         }
  74 done
  75
  76 newline='
  77 '
  78 IFS=$newline
  79
  80
  81 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
  82 case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
  83 ?*) PS3=
  84 esac
  85
  86
  87 # Begin the main loop.  We come back here if the user wants to retry.
  88 while
  89
  90         echo >&2 'Please identify a location' \
  91                 'so that time zone rules can be set correctly.'
  92
  93         continent=
  94         country=
  95         region=
  96
  97
  98         # Ask the user for continent or ocean.
  99
 100         echo >&2 'Please select a continent or ocean.'
 101
 102         select continent in \
 103             Africa \
 104             Americas \
 105             Antarctica \
 106             'Arctic Ocean' \
 107             Asia \
 108             'Atlantic Ocean' \
 109             Australia \
 110             Europe \
 111             'Indian Ocean' \
 112             'Pacific Ocean' \
 113             'none - I want to specify the time zone using the Posix TZ format.'
 114         do
 115             case $continent in
 116             '')
 117                 echo >&2 'Please enter a number in range.';;
 118             ?*)
 119                 case $continent in
 120                 Americas) continent=America;;
 121                 *' '*) continent=$(expr "$continent" : '\([^ ]*\)')
 122                 esac
 123                 break
 124             esac
 125         done
 126         case $continent in
 127         '')
 128                 exit 1;;
 129         none)
 130                 # Ask the user for a Posix TZ string.  Check that it conforms.
 131                 while
 132                         echo >&2 'Please enter the desired value' \
 133                                 'of the TZ environment variable.'
 134                         echo >&2 'For example, GST-10 is a zone named GST' \
 135                                 'that is 10 hours ahead (east) of UTC.'
 136                         read TZ
 137                         $AWK -v TZ="$TZ" 'BEGIN {
 138                                 tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
 139                                 time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
 140                                 offset = "[-+]?" time
 141                                 date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
 142                                 datetime = "," date "(/" time ")?"
 143                                 tzpattern = "^(:.*|" tzname offset "(" tzname \
 144                                   "(" offset ")?(" datetime datetime ")?)?)$"
 145                                 if (TZ ~ tzpattern) exit 1
 146                                 exit 0
 147                         }'
 148                 do
 149                         echo >&2 "\`$TZ' is not a conforming" \
 150                                 'Posix time zone string.'
 151                 done
 152                 TZ_for_date=$TZ;;
 153         *)
 154                 # Get list of names of countries in the continent or ocean.
 155                 countries=$($AWK -F'\t' \
 156                         -v continent="$continent" \
 157                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 158                 '
 159                         /^#/ { next }
 160                         $3 ~ ("^" continent "/") {
 161                                 if (!cc_seen[$1]++) cc_list[++ccs] = $1
 162                         }
 163                         END {
 164                                 while (getline <TZ_COUNTRY_TABLE) {
 165                                         if ($0 !~ /^#/) cc_name[$1] = $2
 166                                 }
 167                                 for (i = 1; i <= ccs; i++) {
 168                                         country = cc_list[i]
 169                                         if (cc_name[country]) {
 170                                           country = cc_name[country]
 171                                         }
 172                                         print country
 173                                 }
 174                         }
 175                 ' <$TZ_ZONE_TABLE | sort -f)
 176
 177
 178                 # If there's more than one country, ask the user which one.
 179                 case $countries in
 180                 *"$newline"*)
 181                         echo >&2 'Please select a country.'
 182                         select country in $countries
 183                         do
 184                             case $country in
 185                             '') echo >&2 'Please enter a number in range.';;
 186                             ?*) break
 187                             esac
 188                         done
 189
 190                         case $country in
 191                         '') exit 1
 192                         esac;;
 193                 *)
 194                         country=$countries
 195                 esac
 196
 197
 198                 # Get list of names of time zone rule regions in the country.
 199                 regions=$($AWK -F'\t' \
 200                         -v country="$country" \
 201                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 202                 '
 203                         BEGIN {
 204                                 cc = country
 205                                 while (getline <TZ_COUNTRY_TABLE) {
 206                                         if ($0 !~ /^#/  &&  country == $2) {
 207                                                 cc = $1
 208                                                 break
 209                                         }
 210                                 }
 211                         }
 212                         $1 == cc { print $4 }
 213                 ' <$TZ_ZONE_TABLE)
 214
 215
 216                 # If there's more than one region, ask the user which one.
 217                 case $regions in
 218                 *"$newline"*)
 219                         echo >&2 'Please select one of the following' \
 220                                 'time zone regions.'
 221                         select region in $regions
 222                         do
 223                                 case $region in
 224                                 '') echo >&2 'Please enter a number in range.';;
 225                                 ?*) break
 226                                 esac
 227                         done
 228                         case $region in
 229                         '') exit 1
 230                         esac;;
 231                 *)
 232                         region=$regions
 233                 esac
 234
 235                 # Determine TZ from country and region.
 236                 TZ=$($AWK -F'\t' \
 237                         -v country="$country" \
 238                         -v region="$region" \
 239                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 240                 '
 241                         BEGIN {
 242                                 cc = country
 243                                 while (getline <TZ_COUNTRY_TABLE) {
 244                                         if ($0 !~ /^#/  &&  country == $2) {
 245                                                 cc = $1
 246                                                 break
 247                                         }
 248                                 }
 249                         }
 250                         $1 == cc && $4 == region { print $3 }
 251                 ' <$TZ_ZONE_TABLE)
 252
 253                 # Make sure the corresponding zoneinfo file exists.
 254                 TZ_for_date=$TZDIR/$TZ
 255                 <$TZ_for_date || {
 256                         echo >&2 "$0: time zone files are not set up correctly"
 257                         exit 1
 258                 }
 259         esac
 260
 261
 262         # Use the proposed TZ to output the current date relative to UTC.
 263         # Loop until they agree in seconds.
 264         # Give up after 8 unsuccessful tries.
 265
 266         extra_info=
 267         for i in 1 2 3 4 5 6 7 8
 268         do
 269                 TZdate=$(LANG=C TZ="$TZ_for_date" date)
 270                 UTdate=$(LANG=C TZ=UTC0 date)
 271                 TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
 272                 UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
 273                 case $TZsec in
 274                 $UTsec)
 275                         extra_info="
 276 Local time is now:      $TZdate.
 277 Universal Time is now:  $UTdate."
 278                         break
 279                 esac
 280         done
 281
 282
 283         # Output TZ info and ask the user to confirm.
 284
 285         echo >&2 ""
 286         echo >&2 "The following information has been given:"
 287         echo >&2 ""
 288         case $country+$region in
 289         ?*+?*)  echo >&2 "      $country$newline        $region";;
 290         ?*+)    echo >&2 "      $country";;
 291         +)      echo >&2 "      TZ='$TZ'"
 292         esac
 293         echo >&2 ""
 294         echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
 295         echo >&2 "Is the above information OK?"
 296
 297         ok=
 298         select ok in Yes No
 299         do
 300             case $ok in
 301             '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
 302             ?*) break
 303             esac
 304         done
 305         case $ok in
 306         '') exit 1;;
 307         Yes) break
 308         esac
 309 do :
 310 done
 311
 312 case $SHELL in
 313 *csh) file=.login line="setenv TZ '$TZ'";;
 314 *) file=.profile line="TZ='$TZ'; export TZ"
 315 esac
 316
 317 echo >&2 "
 318 You can make this change permanent for yourself by appending the line
 319         $line
 320 to the file '$file' in your home directory; then log out and log in again.
 321
 322 Here is that TZ value again, this time on standard output so that you
 323 can use the $0 command in shell scripts:"
 324
 325 echo "$TZ"