lib/libc/time/tzselect.ksh

   1 #! /bin/bash
   2 #
   3 #       $NetBSD: tzselect.ksh,v 1.9 2013/09/20 19:06:54 christos Exp $
   4 #
   5 PKGVERSION='(tzcode) '
   6 TZVERSION=see_Makefile
   7 REPORT_BUGS_TO=tz@iana.org
   8
   9 # Ask the user about the time zone, and output the resulting TZ value to stdout.
  10 # Interact with the user via stderr and stdin.
  11
  12 # Contributed by Paul Eggert.
  13
  14 # Porting notes:
  15 #
  16 # This script requires a Posix-like shell with the extension of a
  17 # 'select' statement.  The 'select' statement was introduced in the
  18 # Korn shell and is available in Bash and other shell implementations.
  19 # If your host lacks both Bash and the Korn shell, you can get their
  20 # source from one of these locations:
  21 #
  22 #       Bash <http://www.gnu.org/software/bash/bash.html>
  23 #       Korn Shell <http://www.kornshell.com/>
  24 #       Public Domain Korn Shell <http://www.cs.mun.ca/~michael/pdksh/>
  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,
  28 # you can use either of the following free programs instead:
  29 #
  30 #       Gawk (GNU awk) <http://www.gnu.org/software/gawk/>
  31 #       mawk <http://invisible-island.net/mawk/>
  32
  33
  34 # Specify default values for environment variables if they are unset.
  35 : ${AWK=awk}
  36 : ${TZDIR=$(pwd)}
  37
  38 # Check for awk Posix compliance.
  39 ($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
  40 [ $? = 123 ] || {
  41         echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
  42         exit 1
  43 }
  44
  45 coord=
  46 location_limit=10
  47
  48 usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT]
  49 Select a time zone interactively.
  50
  51 Options:
  52
  53   -c COORD
  54     Instead of asking for continent and then country and then city,
  55     ask for selection from time zones whose largest cities
  56     are closest to the location with geographical coordinates COORD.
  57     COORD should use ISO 6709 notation, for example, '-c +4852+00220'
  58     for Paris (in degrees and minutes, North and East), or
  59     '-c -35-058' for Buenos Aires (in degrees, South and West).
  60
  61   -n LIMIT
  62     Display at most LIMIT locations when -c is used (default $location_limit).
  63
  64   --version
  65     Output version information.
  66
  67   --help
  68     Output this help.
  69
  70 Report bugs to $REPORT_BUGS_TO."
  71
  72 while getopts c:n:-: opt
  73 do
  74     case $opt$OPTARG in
  75     c*)
  76         coord=$OPTARG ;;
  77     n*)
  78         location_limit=$OPTARG ;;
  79     -help)
  80         exec echo "$usage" ;;
  81     -version)
  82         exec echo "tzselect $PKGVERSION$TZVERSION" ;;
  83     -*)
  84         echo >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1 ;;
  85     *)
  86         echo >&2 "$0: try '$0 --help'"; exit 1 ;;
  87     esac
  88 done
  89
  90 shift $((OPTIND-1))
  91 case $# in
  92 0) ;;
  93 *) echo >&2 "$0: $1: unknown argument"; exit 1 ;;
  94 esac
  95
  96 # Make sure the tables are readable.
  97 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
  98 TZ_ZONE_TABLE=$TZDIR/zone.tab
  99 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
 100 do
 101         <$f || {
 102                 echo >&2 "$0: time zone files are not set up correctly"
 103                 exit 1
 104         }
 105 done
 106
 107 newline='
 108 '
 109 IFS=$newline
 110
 111
 112 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
 113 case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
 114 ?*) PS3=
 115 esac
 116
 117 # Awk script to read a time zone table and output the same table,
 118 # with each column preceded by its distance from 'here'.
 119 output_distances='
 120   BEGIN {
 121     FS = "\t"
 122     while (getline <TZ_COUNTRY_TABLE)
 123       if ($0 ~ /^[^#]/)
 124         country[$1] = $2
 125     country["US"] = "US" # Otherwise the strings get too long.
 126   }
 127   function convert_coord(coord, deg, min, ilen, sign, sec) {
 128     if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9][0-9][0-9]([^0-9]|$)/) {
 129       degminsec = coord
 130       intdeg = degminsec < 0 ? -int(-degminsec / 10000) : int(degminsec / 10000)
 131       minsec = degminsec - intdeg * 10000
 132       intmin = minsec < 0 ? -int(-minsec / 100) : int(minsec / 100)
 133       sec = minsec - intmin * 100
 134       deg = (intdeg * 3600 + intmin * 60 + sec) / 3600
 135     } else if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9]([^0-9]|$)/) {
 136       degmin = coord
 137       intdeg = degmin < 0 ? -int(-degmin / 100) : int(degmin / 100)
 138       min = degmin - intdeg * 100
 139       deg = (intdeg * 60 + min) / 60
 140     } else
 141       deg = coord
 142     return deg * 0.017453292519943296
 143   }
 144   function convert_latitude(coord) {
 145     match(coord, /..*[-+]/)
 146     return convert_coord(substr(coord, 1, RLENGTH - 1))
 147   }
 148   function convert_longitude(coord) {
 149     match(coord, /..*[-+]/)
 150     return convert_coord(substr(coord, RLENGTH))
 151   }
 152   # Great-circle distance between points with given latitude and longitude.
 153   # Inputs and output are in radians.  This uses the great-circle special
 154   # case of the Vicenty formula for distances on ellipsoids.
 155   function dist(lat1, long1, lat2, long2, dlong, x, y, num, denom) {
 156     dlong = long2 - long1
 157     x = cos (lat2) * sin (dlong)
 158     y = cos (lat1) * sin (lat2) - sin (lat1) * cos (lat2) * cos (dlong)
 159     num = sqrt (x * x + y * y)
 160     denom = sin (lat1) * sin (lat2) + cos (lat1) * cos (lat2) * cos (dlong)
 161     return atan2(num, denom)
 162   }
 163   BEGIN {
 164     coord_lat = convert_latitude(coord)
 165     coord_long = convert_longitude(coord)
 166   }
 167   /^[^#]/ {
 168     here_lat = convert_latitude($2)
 169     here_long = convert_longitude($2)
 170     line = $1 "\t" $2 "\t" $3 "\t" country[$1]
 171     if (NF == 4)
 172       line = line " - " $4
 173     printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), line
 174   }
 175 '
 176
 177 # Begin the main loop.  We come back here if the user wants to retry.
 178 while
 179
 180         echo >&2 'Please identify a location' \
 181                 'so that time zone rules can be set correctly.'
 182
 183         continent=
 184         country=
 185         region=
 186
 187         case $coord in
 188         ?*)
 189                 continent=coord;;
 190         '')
 191
 192         # Ask the user for continent or ocean.
 193
 194         echo >&2 'Please select a continent, ocean, "coord", or "TZ".'
 195
 196         quoted_continents=$(
 197           $AWK -F'\t' '
 198             /^[^#]/ {
 199               entry = substr($3, 1, index($3, "/") - 1)
 200               if (entry == "America")
 201                 entry = entry "s"
 202               if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/)
 203                 entry = entry " Ocean"
 204               printf "'\''%s'\''\n", entry
 205             }
 206           ' $TZ_ZONE_TABLE |
 207           sort -u |
 208           tr '\n' ' '
 209           echo ''
 210         )
 211
 212         eval '
 213             select continent in '"$quoted_continents"' \
 214                 "coord - I want to use geographical coordinates." \
 215                 "TZ - I want to specify the time zone using the Posix TZ format."
 216             do
 217                 case $continent in
 218                 "")
 219                     echo >&2 "Please enter a number in range.";;
 220                 ?*)
 221                     case $continent in
 222                     Americas) continent=America;;
 223                     *" "*) continent=$(expr "$continent" : '\''\([^ ]*\)'\'')
 224                     esac
 225                     break
 226                 esac
 227             done
 228         '
 229         esac
 230
 231         case $continent in
 232         '')
 233                 exit 1;;
 234         TZ)
 235                 # Ask the user for a Posix TZ string.  Check that it conforms.
 236                 while
 237                         echo >&2 'Please enter the desired value' \
 238                                 'of the TZ environment variable.'
 239                         echo >&2 'For example, GST-10 is a zone named GST' \
 240                                 'that is 10 hours ahead (east) of UTC.'
 241                         read TZ
 242                         $AWK -v TZ="$TZ" 'BEGIN {
 243                                 tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
 244                                 time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
 245                                 offset = "[-+]?" time
 246                                 date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
 247                                 datetime = "," date "(/" time ")?"
 248                                 tzpattern = "^(:.*|" tzname offset "(" tzname \
 249                                   "(" offset ")?(" datetime datetime ")?)?)$"
 250                                 if (TZ ~ tzpattern) exit 1
 251                                 exit 0
 252                         }'
 253                 do
 254                         echo >&2 "\`$TZ' is not a conforming" \
 255                                 'Posix time zone string.'
 256                 done
 257                 TZ_for_date=$TZ;;
 258         *)
 259                 case $continent in
 260                 coord)
 261                     case $coord in
 262                     '')
 263                         echo >&2 'Please enter coordinates' \
 264                                 'in ISO 6709 notation.'
 265                         echo >&2 'For example, +4042-07403 stands for'
 266                         echo >&2 '40 degrees 42 minutes north,' \
 267                                 '74 degrees 3 minutes west.'
 268                         read coord;;
 269                     esac
 270                     distance_table=$($AWK \
 271                             -v coord="$coord" \
 272                             -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 273                             "$output_distances" <$TZ_ZONE_TABLE |
 274                       sort -n |
 275                       sed "${location_limit}q"
 276                     )
 277                     regions=$(echo "$distance_table" | $AWK '
 278                       BEGIN { FS = "\t" }
 279                       { print $NF }
 280                     ')
 281                     echo >&2 'Please select one of the following' \
 282                             'time zone regions,'
 283                     echo >&2 'listed roughly in increasing order' \
 284                             "of distance from $coord".
 285                     select region in $regions
 286                     do
 287                         case $region in
 288                         '') echo >&2 'Please enter a number in range.';;
 289                         ?*) break;;
 290                         esac
 291                     done
 292                     TZ=$(echo "$distance_table" | $AWK -v region="$region" '
 293                       BEGIN { FS="\t" }
 294                       $NF == region { print $4 }
 295                     ')
 296                     ;;
 297                 *)
 298                 # Get list of names of countries in the continent or ocean.
 299                 countries=$($AWK -F'\t' \
 300                         -v continent="$continent" \
 301                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 302                 '
 303                         /^#/ { next }
 304                         $3 ~ ("^" continent "/") {
 305                                 if (!cc_seen[$1]++) cc_list[++ccs] = $1
 306                         }
 307                         END {
 308                                 while (getline <TZ_COUNTRY_TABLE) {
 309                                         if ($0 !~ /^#/) cc_name[$1] = $2
 310                                 }
 311                                 for (i = 1; i <= ccs; i++) {
 312                                         country = cc_list[i]
 313                                         if (cc_name[country]) {
 314                                           country = cc_name[country]
 315                                         }
 316                                         print country
 317                                 }
 318                         }
 319                 ' <$TZ_ZONE_TABLE | sort -f)
 320
 321
 322                 # If there's more than one country, ask the user which one.
 323                 case $countries in
 324                 *"$newline"*)
 325                         echo >&2 'Please select a country' \
 326                                 'whose clocks agree with yours.'
 327                         select country in $countries
 328                         do
 329                             case $country in
 330                             '') echo >&2 'Please enter a number in range.';;
 331                             ?*) break
 332                             esac
 333                         done
 334
 335                         case $country in
 336                         '') exit 1
 337                         esac;;
 338                 *)
 339                         country=$countries
 340                 esac
 341
 342
 343                 # Get list of names of time zone rule regions in the country.
 344                 regions=$($AWK -F'\t' \
 345                         -v country="$country" \
 346                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 347                 '
 348                         BEGIN {
 349                                 cc = country
 350                                 while (getline <TZ_COUNTRY_TABLE) {
 351                                         if ($0 !~ /^#/  &&  country == $2) {
 352                                                 cc = $1
 353                                                 break
 354                                         }
 355                                 }
 356                         }
 357                         $1 == cc { print $4 }
 358                 ' <$TZ_ZONE_TABLE)
 359
 360
 361                 # If there's more than one region, ask the user which one.
 362                 case $regions in
 363                 *"$newline"*)
 364                         echo >&2 'Please select one of the following' \
 365                                 'time zone regions.'
 366                         select region in $regions
 367                         do
 368                                 case $region in
 369                                 '') echo >&2 'Please enter a number in range.';;
 370                                 ?*) break
 371                                 esac
 372                         done
 373                         case $region in
 374                         '') exit 1
 375                         esac;;
 376                 *)
 377                         region=$regions
 378                 esac
 379
 380                 # Determine TZ from country and region.
 381                 TZ=$($AWK -F'\t' \
 382                         -v country="$country" \
 383                         -v region="$region" \
 384                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 385                 '
 386                         BEGIN {
 387                                 cc = country
 388                                 while (getline <TZ_COUNTRY_TABLE) {
 389                                         if ($0 !~ /^#/  &&  country == $2) {
 390                                                 cc = $1
 391                                                 break
 392                                         }
 393                                 }
 394                         }
 395                         $1 == cc && $4 == region { print $3 }
 396                 ' <$TZ_ZONE_TABLE)
 397                 esac
 398
 399                 # Make sure the corresponding zoneinfo file exists.
 400                 TZ_for_date=$TZDIR/$TZ
 401                 <$TZ_for_date || {
 402                         echo >&2 "$0: time zone files are not set up correctly"
 403                         exit 1
 404                 }
 405         esac
 406
 407
 408         # Use the proposed TZ to output the current date relative to UTC.
 409         # Loop until they agree in seconds.
 410         # Give up after 8 unsuccessful tries.
 411
 412         extra_info=
 413         for i in 1 2 3 4 5 6 7 8
 414         do
 415                 TZdate=$(LANG=C TZ="$TZ_for_date" date)
 416                 UTdate=$(LANG=C TZ=UTC0 date)
 417                 TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
 418                 UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
 419                 case $TZsec in
 420                 $UTsec)
 421                         extra_info="
 422 Local time is now:      $TZdate.
 423 Universal Time is now:  $UTdate."
 424                         break
 425                 esac
 426         done
 427
 428
 429         # Output TZ info and ask the user to confirm.
 430
 431         echo >&2 ""
 432         echo >&2 "The following information has been given:"
 433         echo >&2 ""
 434         case $country%$region%$coord in
 435         ?*%?*%) echo >&2 "      $country$newline        $region";;
 436         ?*%%)   echo >&2 "      $country";;
 437         %?*%?*) echo >&2 "      coord $coord$newline    $region";;
 438         %%?*)   echo >&2 "      coord $coord";;
 439         +)      echo >&2 "      TZ='$TZ'"
 440         esac
 441         echo >&2 ""
 442         echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
 443         echo >&2 "Is the above information OK?"
 444
 445         ok=
 446         select ok in Yes No
 447         do
 448             case $ok in
 449             '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
 450             ?*) break
 451             esac
 452         done
 453         case $ok in
 454         '') exit 1;;
 455         Yes) break
 456         esac
 457 do coord=
 458 done
 459
 460 case $SHELL in
 461 *csh) file=.login line="setenv TZ '$TZ'";;
 462 *) file=.profile line="TZ='$TZ'; export TZ"
 463 esac
 464
 465 echo >&2 "
 466 You can make this change permanent for yourself by appending the line
 467         $line
 468 to the file '$file' in your home directory; then log out and log in again.
 469
 470 Here is that TZ value again, this time on standard output so that you
 471 can use the $0 command in shell scripts:"
 472
 473 echo "$TZ"