checklinks.awk

# Check links in tz tables.

# Contributed by Paul Eggert.

BEGIN {
    # Special marker indicating that the name is defined as a Zone.
    # It is a newline so that it cannot match a valid name.
    # It is not null so that its slot does not appear unset.
    Zone = "\n"
}

/^Zone/ {
    if (defined[$2]) {
	if (defined[$2] == Zone) {
	    printf "%s: Zone has duplicate definition\n", $2
	} else {
	    printf "%s: Link with same name as Zone\n", $2
	}
	status = 1
    }
    defined[$2] = Zone
}

/^Link/ {
    if (defined[$3]) {
	if (defined[$3] == Zone) {
	    printf "%s: Link with same name as Zone\n", $3
	} else if (defined[$3] == $2) {
	    printf "%s: Link has duplicate definition\n", $3
	} else {
	    printf "%s: Link to both %s and %s\n", $3, defined[$3], $2
	}
	status = 1
    }
    used[$2] = 1
    defined[$3] = $2
}

END {
    for (tz in used) {
	if (defined[tz] != Zone) {
	    printf "%s: Link to non-zone\n", tz
	    status = 1
	}
    }

    exit status
}