#!/usr/bin/tclsh
# \
exec expectk -f "$0" ${1+"$@"}
# tkpasswd - Change passwords using Expectk
# Author: Don Libes, NIST, October 1, 1993
# Version: 1.8 - Added support for Tk 4.1

# There is no man page.  However, there is some on-line help when you run
# the program.  Technical details and insights are described in the
# O'Reilly book "Exploring Expect".

proc prog_exists {prog} {
    global env

    foreach dir [split $env(PATH) :] {
	if {[file executable $dir/$prog]} {
	    return 1
	}
    }
    return 0
}

frame .type -relief raised -bd 1

radiobutton .passwd -text passwd -variable passwd_cmd \
	-value {passwd {cat /etc/passwd}} \
	-anchor w -command get_users -relief flat
pack .passwd -in .type -fill x

if {[prog_exists yppasswd]} {
    radiobutton .yppasswd -text yppasswd -variable passwd_cmd \
	    -value {yppasswd {ypcat passwd}} \
	    -anchor w -command get_users -relief flat
    pack .yppasswd -in .type -fill x
}

if {[prog_exists nispasswd]} {
    radiobutton .nispasswd -text nispasswd -variable passwd_cmd \
	    -value {nispasswd {niscat passwd}} \
	    -anchor w -command get_users -relief flat
    pack .nispasswd -in .type -fill x 
}
pack .type -fill x

frame .sort -relief raised -bd 1
radiobutton .unsorted -text unsorted -variable sort_cmd -value " " \
	-anchor w -relief flat -command get_users
radiobutton .name -text name -variable sort_cmd -value "| sort" \
	-anchor w -relief flat -command get_users
radiobutton .uid -text uid -variable sort_cmd -value "| sort -t: -n +2" \
	-anchor w -relief flat -command get_users
pack .unsorted .name .uid -in .sort -fill x
pack .sort -fill x

frame .users -relief raised -bd 1
# has to be wide enough for 8+1+5=14
text .names -yscrollcommand ".scroll set" -width 14 -height 1 \
	-font "*-bold-o-normal-*-120-*-m-*" -setgrid 1
.names tag configure nopassword -relief raised
.names tag configure selection -relief raised

set iscolor 0
if {[winfo depth .] > 1} {
    set iscolor 1
}

if {$iscolor} {
    .names tag configure nopassword -background red
    .names tag configure selection -background green
} else {
    .names tag configure nopassword -background  black -foreground white
    .names tag configure selection -background white -foreground black
}
scrollbar .scroll -command ".names yview" -relief raised
pack .scroll -in .users -side left -fill y
pack .names  -in .users -side left -fill y
pack .users -expand 1 -fill y

wm minsize . 14 1
wm maxsize . 14 999
wm geometry . 14x10

frame .password_frame -relief raised -bd 1
entry .password -textvar password -relief sunken -width 1
focus .password
bind .password <Return> password_set
label .prompt -text "Password:" -bd 0
button .password_set -text "set" -command password_set
button .generate_button -text "generate" -command password_generate
pack .prompt .password -in .password_frame -fill x -padx 2 -pady 2
pack .password_set .generate_button -in .password_frame -side left -expand 1 -fill x -padx 2 -pady 2
pack .password_frame -fill x

set dict_loaded 0
checkbutton .dict -text "test dictionary" -variable dict_check \
	-command {if {!$dict_loaded} load_dict} \
	-anchor w
pack .dict -fill x -padx 2 -pady 2


button .quit -text quit -command exit
button .help_button -text help -command help
pack .quit .help_button -side left -expand 1 -fill x -padx 2 -pady 2

proc help {} {
    if {[catch {toplevel .help}]} return
    message .help.text -text \
"tkpasswd - written by Don Libes, NIST, 10/1/93.

Click on passwd (local users) or yppasswd (NIS users).\
Select user using mouse (or keys - see below).\
Enter password or press ^G to generate a random password.\
(Press ^A to adjust the generation parameters.)\
Press return to set the password.\
If the dictionary is enabled and the password is in it,\
the password is rejected.

You must be root to set local passwords besides your own.\
If you are not root, you must also enter an old password\
when requested.

You do not have to move mouse into password field(s) to enter password.\
^U clears password field.\
^N and ^P select next/previous user.\
M-n and M-p select next/previous user with no password.\
(Users with no passwords are highlighted.)"

    button .help.ok -text "ok" -command {destroy .help}
    pack .help.text
    pack .help.ok -fill x -padx 2 -pady 2
}

# get list of local users
proc get_users {} {
    global sort_cmd passwd_cmd
    global nopasswords	;# line numbers of entries with no passwords
    global last_line	;# last line of text box
    global selection_line

    .names delete 1.0 end

    set file [open "|[lindex $passwd_cmd 1] $sort_cmd"]
    set last_line 1
    set nopasswords {}
    while {[gets $file buf] != -1} {
	set buf [split $buf :]
	if {[llength $buf]>2} {
	    # normal password entry
	    .names insert end "[format "%-8.8s %5d" [lindex $buf 0] [lindex $buf 2]]\n"
	    if {0==[string compare [lindex $buf 1] ""]} {
		.names tag add nopassword \
			{end - 2 line linestart} \
			{end - 2 line lineend}
		lappend nopasswords $last_line
	    }
	} else {
	    # +name style entry
	    .names insert end "$buf\n"
	}
	incr last_line
    }
    incr last_line -1
    close $file
    set selection_line 0
}

proc feedback {msg} {
    global password

    set password $msg
    .password select from 0
    .password select to end
    update
}

proc load_dict {} {
    global dict dict_loaded

    feedback "loading dictionary..."

    if {0==[catch {open /usr/dict/words} file]} {
	foreach w [split [read $file] "\n"] {set dict($w) ""}
	close $file
	set dict_loaded 1
	feedback "dictionary loaded"
    } else {
	feedback "dictionary missing"
	.dict deselect
    }
}

# put whatever security checks you like in here
proc weak_password {password} {
    global dict dict_check

    if {$dict_check} {
	feedback "checking password"

	if {[info exists dict($password)]} {
	    feedback "sorry - in dictionary"
	    return 1
	}
    }
    return 0
}

proc password_set {} {
    global password passwd_cmd selection_line

    set new_password $password

    if {$selection_line==0} {
	feedback "select a user first"
	return
    }
    set user [lindex [.names get selection.first selection.last] 0]

    if {[weak_password $password]} return

    feedback "setting password . . ."

    set cmd [lindex $passwd_cmd 0]
    spawn -noecho $cmd $user
    log_user 0
    set last_msg "error in $cmd"
    while {1} {
	expect {
	    -nocase "old password:" {
		exp_send "[get_old_password]\r"
	    } "assword*:" {
		exp_send "$new_password\r"
	    } -re "(.*)\r\n" {
		set last_msg $expect_out(1,string)
	    } eof break
	}
    }
    set status [wait]
    if {[lindex $status 3]==0} {
	feedback "set successfully"
    } else {
	feedback $last_msg
    }
}

# defaults for generating passwords
set length 9
set minnum 2
set minlower 5
set minupper 2
set distribute 0

proc parameter_filename {} {
    set file .tkpasswd.rc
    if {[info exists env(DOTDIR)]} {
	set file "$env(DOTDIR)/$file"
    }
    return ~/$file
}

catch {source [parameter_filename]}

# save parameters in a file
proc save_parameters {} {
    global minnum minlower minupper length

    if {[catch {open [parameter_filename] w} f]} {
	# should never happen, so don't bother with window code
	puts "tkpasswd: could not write [parameter_filename]"
	return
    }
    puts $f "# This is the .tkpasswd.rc file.  Do not edit it by hand as"
    puts $f "# it is automatically maintained by tkpasswd.  Any manual"
    puts $f "# modifications will be lost."
    puts $f ""
    puts $f "set length $length"
    puts $f "set minnum $minnum"
    puts $f "set minupper $minupper"
    puts $f "set minlower $minlower"
    close $f
}

# insert char into password at a random position
proc insert {pvar char} {
    upvar $pvar p

    set p [linsert $p [rand [expr 1+[llength $p]]] $char]
}

# given a size, distribute between left and right hands
# taking into account where we left off
proc psplit {max lvar rvar} {
    upvar $lvar left $rvar right
    global isleft

    if {$isleft} {
	set right [expr $max/2]
	set left [expr $max-$right]
	set isleft [expr !($max%2)]
    } else {
	set left [expr $max/2]
	set right [expr $max-$left]
	set isleft [expr $max%2]
    }
}

proc password_generate {} {
    global password length minnum minlower minupper
    global lpass rpass initially_left isleft
    global distribute

    if {$distribute} {
	set lkeys {q w e r t a s d f g z x c v b}
	set rkeys {y u i o p h j k l n m}
	set lnums {1 2 3 4 5 6}
	set rnums {7 8 9 0}
    } else {
	set lkeys {a b c d e f g h i j k l m n o p q r s t u v w x y z}
	set rkeys {a b c d e f g h i j k l m n o p q r s t u v w x y z}
	set lnums {0 1 2 3 4 5 6 7 8 9}
	set rnums {0 1 2 3 4 5 6 7 8 9}
    }
    set lkeys_length [llength $lkeys]
    set rkeys_length [llength $rkeys]
    set lnums_length [llength $lnums]
    set rnums_length [llength $rnums]

    # if there is any underspecification, use additional lowercase letters
    set minlower [expr $length - ($minnum + $minupper)]


    set lpass ""		;# password chars typed by left hand
    set rpass ""		;# password chars typed by right hand
    set password ""		;# merged password

    # choose left or right starting hand
    set initially_left [set isleft [rand 2]]

    psplit $minnum left right
    for {set i 0} {$i<$left} {incr i} {
	insert lpass [lindex $lnums [rand $lnums_length]]
    }
    for {set i 0} {$i<$right} {incr i} {
	insert rpass [lindex $rnums [rand $rnums_length]]
    }

    psplit $minlower left right
    for {set i 0} {$i<$left} {incr i} {
	insert lpass [lindex $lkeys [rand $lkeys_length]]
    }
    for {set i 0} {$i<$right} {incr i} {
	insert rpass [lindex $rkeys [rand $rkeys_length]]
    }

    psplit $minupper left right
    for {set i 0} {$i<$left} {incr i} {
	insert lpass [string toupper [lindex $lkeys [rand $lkeys_length]]]
    }
    for {set i 0} {$i<$right} {incr i} {
	insert rpass [string toupper [lindex $rkeys [rand $rkeys_length]]]
    }

    # merge results together
    if {$initially_left} {
	regexp "(\[^ ]*) *(.*)" "$lpass" x password lpass
	while {[llength $lpass]} {
	    regexp "(\[^ ]*) *(.*)" "$password$rpass" x password rpass
	    regexp "(\[^ ]*) *(.*)" "$password$lpass" x password lpass
	}
	if {[llength $rpass]} {
	    append password $rpass
	}		
    } else {
	regexp "(\[^ ]*) *(.*)" "$rpass" x password rpass
	while {[llength $rpass]} {
	    regexp "(\[^ ]*) *(.*)" "$password$lpass" x password lpass
	    regexp "(\[^ ]*) *(.*)" "$password$rpass" x password rpass
	}
	if {[llength $lpass]} {
	    append password $lpass
	}		
    }
}

proc rand {m} {
    expr {int($m*rand())}
}

proc gen_bad_args {msg} {
    if {![llength [info commands .parameters.errmsg]]} {
	message .parameters.errmsg -aspect 300
	pack .parameters.errmsg
    }
    .parameters.errmsg configure -text "$msg\
	    Please adjust the password generation arguments."
}


# tell tab what window to move between
set parm_tabList {}

# The procedure below is invoked in response to tabs in the entry
# windows.  It moves the focus to the next window in the tab list.
# Arguments:
#
# list -	Ordered list of windows to receive focus

proc Tab {list} {
    set i [lsearch $list [focus]]
    if {$i < 0} {
	set i 0
    } else {
	incr i
	if {$i >= [llength $list]} {
	    set i 0
	}
    }
    focus [lindex $list $i]
}

# adjust args used in password generation
proc adjust_parameters {} {
    global parm_tabList
    set parm_tabList {}

    toplevel [set w .parameters]

    message $w.text -aspect 300 -text \
"These parameters control generation of random passwords.

It is not necessary to move the mouse into this window to operate it.\
Press <tab> to move to the next entry.\
Press <return> or click the <ok> button when you are done."

    foreach desc {
	{length {total length}}
	{minnum {minimum number of digits}}
	{minupper {minimum number of uppercase letters}}
	{minlower {minimum number of lowercase letters}}} {
	    set name [lindex $desc 0]
	    set text [lindex $desc 1]
	    frame $w.$name -bd 1
	    entry $w.$name.entry -relief sunken -width 2 -textvar $name
	    bind $w.$name.entry <Tab> "Tab \$parm_tabList"
	    bind $w.$name.entry <Return> "destroy_parm_window"
	    label $w.$name.text -text $text
	    pack $w.$name.entry -side left
	    pack $w.$name.text -side left
	    lappend parm_tabList $w.$name.entry
    }
    frame $w.2 -bd 1
    checkbutton $w.2.cb -text "alternate characters across hands" \
	    -relief flat -variable distribute
    pack $w.2.cb -side left

    button $w.ok -text "ok" -command "destroy_parm_window"
    pack $w.text -expand 1 -fill x
    pack $w.length $w.minnum $w.minupper $w.minlower $w.2 -expand 1 -fill x
    pack $w.ok -side left -fill x -expand 1 -padx 2 -pady 2

    set oldfocus [focus]
    tkwait visibility $w.length.entry
    focus $w.length.entry
    tkwait window $w
    focus $oldfocus
    save_parameters	
}

proc isnumber {n} {
    regexp "^\[0-9\]+$" $n
}

# destroy parm window IF all values are legal
proc destroy_parm_window {} {
    global minnum minlower minupper length

    set mustbe "must be a number greater than or equal to zero."

    # check all variables
    if {![isnumber $length]} {
	gen_bad_args "The total length $mustbe"
	return
    }
    if {![isnumber $minlower]} {
	gen_bad_args "The minimum number of lowercase characters $mustbe"
	return
    }
    if {![isnumber $minupper]} {
	gen_bad_args "The minimum number of uppercase characters $mustbe"
	return
    }
    if {![isnumber $minnum]} {
	gen_bad_args "The minimum number of digits $mustbe"
	return
    }

    # check constraints
    if {$minnum + $minlower + $minupper > $length} {
	gen_bad_args \
		"It is impossible to generate a $length-character password with\
		$minnum number[pluralize $minnum],\
		$minlower lowercase letter[pluralize $minlower], and\
		$minupper uppercase letter[pluralize $minupper]."
	return
    }

    destroy .parameters
}

# return appropriate ending for a count of "n" nouns
proc pluralize {n} {
    expr $n!=1?"s":""
}


proc get_old_password {} {
    global old

    toplevel .old
    label .old.label -text "Old password:"
    catch {unset old}
    entry .old.entry -textvar old -relief sunken -width 1

    pack .old.label
    pack .old.entry -fill x -padx 2 -pady 2

    bind .old.entry <Return> {destroy .old}
    set oldfocus [focus]
    focus .old.entry
    tkwait visibility .old
    grab .old
    tkwait window .old
    focus $oldfocus
    return $old
}

.unsorted select
.passwd invoke

proc make_selection {} {
    global selection_line last_line

    .names tag remove selection 0.0 end

    # don't let selection go off top of screen
    if {$selection_line < 1} {
	set selection_line $last_line
    } elseif {$selection_line > $last_line} {
	set selection_line 1
    }
    .names yview -pickplace [expr $selection_line-1]
    .names tag add selection $selection_line.0 [expr 1+$selection_line].0
}

proc select_next_nopassword {direction} {
    global selection_line last_line
    global nopasswords
    
    if {0==[llength $nopasswords]} {
	feedback "no null passwords"
	return
    }

    if {$direction==1} {
	# is there a better way to get last element of list?
	if {$selection_line>=[lindex $nopasswords [expr [llength $nopasswords]-1]]} {
	    set selection_line 0
	}
	foreach i $nopasswords {
	    if {$selection_line<$i} break
	}
    } else {
	if {$selection_line<=[lindex $nopasswords 0]} {
	    set selection_line $last_line
	}
	set j [expr [llength $nopasswords]-1]
	for {} {$j>=0} {incr j -1} {
	    set i [lindex $nopasswords $j]
	    if {$selection_line>$i} break
	}
    }
    set selection_line $i
    make_selection
}

proc select {w coords} {
    global selection_line

    $w mark set insert "@$coords linestart"
    $w mark set anchor insert
    set first [$w index "anchor linestart"]
    set last [$w index "insert lineend + 1c"]
    scan $first %d selection_line

    $w tag remove selection 0.0 end
    $w tag add selection $first $last
}

bind Text <1> {select %W %x,%y}
bind Text <Double-1> {select %W %x,%y}
bind Text <Triple-1> {select %W %x,%y}
bind Text <2> {select %W %x,%y}
bind Text <3> {select %W %x,%y}
bind Text <B1-Motion> {}
bind Text <Shift-1> {}
bind Text <Shift-B1-Motion> {}
bind Text <B2-Motion> {}

bind .password <Control-n>	{incr selection_line 1;	make_selection}
bind .password <Control-p>	{incr selection_line -1;make_selection}
bind .password <Meta-n>	{select_next_nopassword 1}
bind .password <Meta-p>	{select_next_nopassword -1}
bind .password <Control-g>	{password_generate}
bind .password <Control-a>	{adjust_parameters}
bind .password <Control-u>	{set password ""}
bind Entry <Control-c>		{exit}
