This file is indexed.

/usr/share/tcltk/tcllib1.16/nns/server.tcl is in tcllib 1.16-dfsg-2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
# -*- tcl -*-
# ### ### ### ######### ######### #########
## Name Service - Server (Singleton)

# ### ### ### ######### ######### #########
## Requirements

package require Tcl 8.4
package require comm             ; # Generic message transport
package require interp           ; # Interpreter helpers.
package require logger           ; # Tracing internal activity
package require nameserv::common ; # Common/shared utilities

namespace eval ::nameserv::server {}

# ### ### ### ######### ######### #########
## API: Start, Stop

proc ::nameserv::server::start {} {
    variable comm
    variable port
    variable localonly

    log::debug "start"
    if {$comm ne ""} return

    log::debug "start /granted"

    set     interp [interp::createEmpty]
    foreach msg {
	Bind
	Release
	Search
	Search/Continuous/Start
	Search/Continuous/Stop
	ProtocolVersion
	ProtocolFeatures
    } {
	interp alias $interp $msg {} ::nameserv::server::$msg
    }

    set comm [comm::comm new ::nameserv::server::COMM \
		  -interp $interp \
		  -port   $port \
		  -listen 1 \
		  -local  $localonly]

    $comm hook lost ::nameserv::server::LOST

    log::debug "UP @$port local-only $localonly"
    return
}

proc ::nameserv::server::stop {} {
    variable comm
    variable names
    variable data

    log::debug "stop"
    if {$comm eq ""} return

    log::debug "stop /granted"

    # This kills all existing connection and destroys the configured
    # -interp as well.

    $comm destroy
    set comm ""

    array unset names *
    array unset data  *

    log::debug "DOWN"
    return
}

proc ::nameserv::server::active? {} {
    variable comm
    return [expr {$comm ne ""}]
}

# ### ### ### ######### ######### #########
## INT: Protocol operations

proc ::nameserv::server::ProtocolVersion  {} {return 1}
proc ::nameserv::server::ProtocolFeatures {} {return {Core Search/Continuous}}

proc ::nameserv::server::Bind {name cdata} {
    variable comm
    variable names
    variable data

    set id [$comm remoteid]

    log::debug "bind ([list $name -> $cdata]), for $id"

    if {[info exists data($name)]} {
	log::debug "bind failed, \"$name\" is already bound"
	return -code error "Name \"$name\" is already bound"
    }

    lappend names($id)  $name
    set     data($name) $cdata

    Search/Continuous/NotifyAdd $name $cdata
    return
}

proc ::nameserv::server::Release {} {
    variable comm
    ReleaseId [$comm remoteid]
    return
}

proc ::nameserv::server::Search {pattern} {
    variable data
    return [array get data $pattern]
}

proc ::nameserv::server::ReleaseId {id} {
    variable names
    variable data
    variable searchi

    log::debug "release id $id"

    # Two steps. Release all searches the client may have open, then
    # all names it may have bound. That last step may trigger
    # notifications for searches by other clients. It must not trigger
    # searches from the client just going away, hence their release
    # first.

    foreach k [array names searchi [list $id *]] {
	Search/Release $k
    }

    if {[info exists names($id)]} {
	set gone {}
	foreach n $names($id) {
	    lappend gone $n $data($n)
	    catch {unset data($n)}

	    log::debug "release name <$n>"
	}
	unset names($id)

	Search/Continuous/NotifyRelease $gone
    }
    return
}

# ### ### ### ######### ######### #########
## Support for continuous and async searches

proc ::nameserv::server::Search/Continuous/Start {tag pattern} {
    variable data
    variable searchi
    variable searchp
    variable comm

    set id [$comm remoteid]

    # Register the search, then generate the initial response.
    # Non-unique tags are silently discarded. Clients will wait
    # forever.

    set k [list $id $tag]

    log::debug "search <$k>"

    if {[info exists searchi($k)]} {
	log::debug "search already known"
	return
    }

    log::debug "search added"

    set searchi($k) $pattern
    lappend searchp($pattern) $k

    $comm send -async $id [list Search/Continuous/Change \
			       $tag add [array get data $pattern]]
    return
}

proc ::nameserv::server::Search/Continuous/Stop {tag} {
    Search/Release [list [$comm remoteid] $tag]
    return
}

proc ::nameserv::server::Search/Release {k} {
    variable searchi
    variable searchp

    # Remove search information from the data store

    if {![info exists searchi($k)]} return

    log::debug "release search <$k>"

    set pattern $searchi($k)
    unset searchi($k)

    set pos [lsearch -exact $searchp($pattern) $k]
    if {$pos < 0} return
    set new [lreplace $searchp($pattern) $pos $pos]
    if {[llength $new]} {
	# Shorten the callback list.
	set searchp($pattern) $new
    } else {
	# Nothing monitors that pattern anymore, remove it completely.
	unset searchp($pattern)
    }
    return
}

proc ::nameserv::server::Search/Continuous/NotifyAdd {name val} {
    variable searchp

    # Abort quickly if there are no searches waiting.
    if {![array size searchp]} return

    foreach p [array names searchp] {
	if {![string match $p $name]} continue
	Notify $p add [list $name $val]
    }
    return
}

proc ::nameserv::server::Search/Continuous/NotifyRelease {gone} {
    variable searchp

    # Abort quickly if there are no searches waiting.
    if {![array size searchp]} return

    array set m $gone
    foreach p [array names searchp] {
	set response [array get m $p]
	if {![llength $response]} continue
	Notify $p remove $response
    }
    return
}

proc ::nameserv::server::Notify {p type response} {
    variable searchp
    variable comm

    foreach item $searchp($p) {
	foreach {id tag} $item break
	$comm send -async $id \
	    [list Search/Continuous/Change $tag $type $response]
    }
    return
}

# ### ### ### ######### ######### #########
## Initialization - In-memory database

namespace eval ::nameserv::server {
    # Database
    # search = list (id tag) : Searches are identified by client and a tag.
    #
    # array (id   -> list (name))      : Names under which a connection is known.
    # array (name -> data)             : Data associated with a name.
    #
    # array (pattern -> list (search)) : Per pattern the list of searches using it.
    # array (search -> pattern)        : Pattern per active search.
    #
    # searchp <~~> names
    # searchi <~~> data

    variable names   ; array set names {}
    variable data    ; array set data  {}
    variable searchp ; array set searchp {}
    variable searchi ; array set searchi {}
}

# ### ### ### ######### ######### #########
## INT: Connection management

proc ::nameserv::server::LOST {args} {
    # Currently just to see when a client goes away.

    upvar 1 id id chan chan reason reason
    ReleaseId $id
    return
}

# ### ### ### ######### ######### #########
## Initialization - System state

namespace eval ::nameserv::server {
    # Object command of the communication channel of the server.
    # If present re-configuration is not possible.

    variable comm {}
}

# ### ### ### ######### ######### #########
## API: Configuration management (host, port)

proc ::nameserv::server::cget {option} {
    return [configure $option]
}

proc ::nameserv::server::configure {args} {
    variable localonly
    variable port
    variable comm

    if {![llength $args]} {
	return [list -localonly $localonly -port $port]
    }
    if {[llength $args] == 1} {
	# cget
	set opt [lindex $args 0]
	switch -exact -- $opt {
	    -localonly { return $localonly }
	    -port      { return $port }
	    default {
		return -code error "bad option \"$opt\", expected -localonly, or -port"
	    }
	}
    }

    # Note: Should -port be made configurable after communication has
    # started it might be necessary to provide code to re-initialize
    # the connections to all known clients using the new
    # configuration.

    while {[llength $args]} {
	set opt [lindex $args 0]
	switch -exact -- $opt {
	    -localonly {
		if {[llength $args] < 2} {
		    return -code error "value for \"$opt\" is missing"
		}
		# Todo: Check boolean 
		set new  [lindex $args 1]
		set args [lrange $args 2 end]

		if {$new == $localonly} continue
		set localonly $new
		if {$comm eq ""} continue
		$comm configure -local $localonly
	    }
	    -port {
		if {$comm ne ""} {
		    return -code error "Unable to configure an active server"
		}
		if {[llength $args] < 2} {
		    return -code error "value for \"$opt\" is missing"
		}
		# Todo: Check non-zero unsigned short integer
		set port [lindex $args 1]
		set args [lrange $args 2 end]
	    }
	    default {
		return -code error "bad option \"$opt\", expected -localonly, or -port"
	    }
	}
    }
    return
}

# ### ### ### ######### ######### #########
## Initialization - Tracing, Configuration

logger::initNamespace ::nameserv::server
namespace eval        ::nameserv::server {
    # Port the server will listen on, and boolean flag determining
    # acceptance of non-local connections.

    variable port      [nameserv::common::port]
    variable localonly 1
}

# ### ### ### ######### ######### #########
## Ready

package provide nameserv::server 0.3.2

##
# ### ### ### ######### ######### #########