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safe.tcl @ 5076

Last change on this file since 5076 was 5049, checked in by landauf, 17 years ago
added tcl files
File size: 26.3 KB

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1	# safe.tcl --
2	#
3	# This file provide a safe loading/sourcing mechanism for safe interpreters.
4	# It implements a virtual path mecanism to hide the real pathnames from the
5	# slave. It runs in a master interpreter and sets up data structure and
6	# aliases that will be invoked when used from a slave interpreter.
7	#
8	# See the safe.n man page for details.
9	#
10	# Copyright (c) 1996-1997 Sun Microsystems, Inc.
11	#
12	# See the file "license.terms" for information on usage and redistribution
13	# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
14	#
15	# RCS: @(#) $Id: safe.tcl,v 1.16 2006/11/03 00:34:52 hobbs Exp $
16
17	#
18	# The implementation is based on namespaces. These naming conventions
19	# are followed:
20	# Private procs starts with uppercase.
21	# Public procs are exported and starts with lowercase
22	#
23
24	# Needed utilities package
25	package require opt 0.4.1;
26
27	# Create the safe namespace
28	namespace eval ::safe {
29
30	# Exported API:
31	namespace export interpCreate interpInit interpConfigure interpDelete \
32	interpAddToAccessPath interpFindInAccessPath setLogCmd
33
34	####
35	#
36	# Setup the arguments parsing
37	#
38	####
39
40	# Make sure that our temporary variable is local to this
41	# namespace. [Bug 981733]
42	variable temp
43
44	# Share the descriptions
45	set temp [::tcl::OptKeyRegister {
46	{-accessPath -list {} "access path for the slave"}
47	{-noStatics "prevent loading of statically linked pkgs"}
48	{-statics true "loading of statically linked pkgs"}
49	{-nestedLoadOk "allow nested loading"}
50	{-nested false "nested loading"}
51	{-deleteHook -script {} "delete hook"}
52	}]
53
54	# create case (slave is optional)
55	::tcl::OptKeyRegister {
56	{?slave? -name {} "name of the slave (optional)"}
57	} ::safe::interpCreate
58	# adding the flags sub programs to the command program
59	# (relying on Opt's internal implementation details)
60	lappend ::tcl::OptDesc(::safe::interpCreate) $::tcl::OptDesc($temp)
61
62	# init and configure (slave is needed)
63	::tcl::OptKeyRegister {
64	{slave -name {} "name of the slave"}
65	} ::safe::interpIC
66	# adding the flags sub programs to the command program
67	# (relying on Opt's internal implementation details)
68	lappend ::tcl::OptDesc(::safe::interpIC) $::tcl::OptDesc($temp)
69	# temp not needed anymore
70	::tcl::OptKeyDelete $temp
71
72
73	# Helper function to resolve the dual way of specifying staticsok
74	# (either by -noStatics or -statics 0)
75	proc InterpStatics {} {
76	foreach v {Args statics noStatics} {
77	upvar $v $v
78	}
79	set flag [::tcl::OptProcArgGiven -noStatics];
80	if {$flag && (!$noStatics == !$statics)
81	&& ([::tcl::OptProcArgGiven -statics])} {
82	return -code error\
83	"conflicting values given for -statics and -noStatics"
84	}
85	if {$flag} {
86	return [expr {!$noStatics}]
87	} else {
88	return $statics
89	}
90	}
91
92	# Helper function to resolve the dual way of specifying nested loading
93	# (either by -nestedLoadOk or -nested 1)
94	proc InterpNested {} {
95	foreach v {Args nested nestedLoadOk} {
96	upvar $v $v
97	}
98	set flag [::tcl::OptProcArgGiven -nestedLoadOk];
99	# note that the test here is the opposite of the "InterpStatics"
100	# one (it is not -noNested... because of the wanted default value)
101	if {$flag && (!$nestedLoadOk != !$nested)
102	&& ([::tcl::OptProcArgGiven -nested])} {
103	return -code error\
104	"conflicting values given for -nested and -nestedLoadOk"
105	}
106	if {$flag} {
107	# another difference with "InterpStatics"
108	return $nestedLoadOk
109	} else {
110	return $nested
111	}
112	}
113
114	####
115	#
116	# API entry points that needs argument parsing :
117	#
118	####
119
120
121	# Interface/entry point function and front end for "Create"
122	proc interpCreate {args} {
123	set Args [::tcl::OptKeyParse ::safe::interpCreate $args]
124	InterpCreate $slave $accessPath \
125	[InterpStatics] [InterpNested] $deleteHook
126	}
127
128	proc interpInit {args} {
129	set Args [::tcl::OptKeyParse ::safe::interpIC $args]
130	if {![::interp exists $slave]} {
131	return -code error "\"$slave\" is not an interpreter"
132	}
133	InterpInit $slave $accessPath \
134	[InterpStatics] [InterpNested] $deleteHook;
135	}
136
137	proc CheckInterp {slave} {
138	if {![IsInterp $slave]} {
139	return -code error \
140	"\"$slave\" is not an interpreter managed by ::safe::"
141	}
142	}
143
144	# Interface/entry point function and front end for "Configure"
145	# This code is awfully pedestrian because it would need
146	# more coupling and support between the way we store the
147	# configuration values in safe::interp's and the Opt package
148	# Obviously we would like an OptConfigure
149	# to avoid duplicating all this code everywhere. -> TODO
150	# (the app should share or access easily the program/value
151	# stored by opt)
152	# This is even more complicated by the boolean flags with no values
153	# that we had the bad idea to support for the sake of user simplicity
154	# in create/init but which makes life hard in configure...
155	# So this will be hopefully written and some integrated with opt1.0
156	# (hopefully for tcl8.1 ?)
157	proc interpConfigure {args} {
158	switch [llength $args] {
159	1 {
160	# If we have exactly 1 argument
161	# the semantic is to return all the current configuration
162	# We still call OptKeyParse though we know that "slave"
163	# is our given argument because it also checks
164	# for the "-help" option.
165	set Args [::tcl::OptKeyParse ::safe::interpIC $args]
166	CheckInterp $slave
167	set res {}
168	lappend res [list -accessPath [Set [PathListName $slave]]]
169	lappend res [list -statics [Set [StaticsOkName $slave]]]
170	lappend res [list -nested [Set [NestedOkName $slave]]]
171	lappend res [list -deleteHook [Set [DeleteHookName $slave]]]
172	join $res
173	}
174	2 {
175	# If we have exactly 2 arguments
176	# the semantic is a "configure get"
177	::tcl::Lassign $args slave arg
178	# get the flag sub program (we 'know' about Opt's internal
179	# representation of data)
180	set desc [lindex [::tcl::OptKeyGetDesc ::safe::interpIC] 2]
181	set hits [::tcl::OptHits desc $arg]
182	if {$hits > 1} {
183	return -code error [::tcl::OptAmbigous $desc $arg]
184	} elseif {$hits == 0} {
185	return -code error [::tcl::OptFlagUsage $desc $arg]
186	}
187	CheckInterp $slave
188	set item [::tcl::OptCurDesc $desc]
189	set name [::tcl::OptName $item]
190	switch -exact -- $name {
191	-accessPath {
192	return [list -accessPath [Set [PathListName $slave]]]
193	}
194	-statics {
195	return [list -statics [Set [StaticsOkName $slave]]]
196	}
197	-nested {
198	return [list -nested [Set [NestedOkName $slave]]]
199	}
200	-deleteHook {
201	return [list -deleteHook [Set [DeleteHookName $slave]]]
202	}
203	-noStatics {
204	# it is most probably a set in fact
205	# but we would need then to jump to the set part
206	# and it is not sure that it is a set action
207	# that the user want, so force it to use the
208	# unambigous -statics ?value? instead:
209	return -code error\
210	"ambigous query (get or set -noStatics ?)\
211	use -statics instead"
212	}
213	-nestedLoadOk {
214	return -code error\
215	"ambigous query (get or set -nestedLoadOk ?)\
216	use -nested instead"
217	}
218	default {
219	return -code error "unknown flag $name (bug)"
220	}
221	}
222	}
223	default {
224	# Otherwise we want to parse the arguments like init and create
225	# did
226	set Args [::tcl::OptKeyParse ::safe::interpIC $args]
227	CheckInterp $slave
228	# Get the current (and not the default) values of
229	# whatever has not been given:
230	if {![::tcl::OptProcArgGiven -accessPath]} {
231	set doreset 1
232	set accessPath [Set [PathListName $slave]]
233	} else {
234	set doreset 0
235	}
236	if {(![::tcl::OptProcArgGiven -statics]) \
237	&& (![::tcl::OptProcArgGiven -noStatics]) } {
238	set statics [Set [StaticsOkName $slave]]
239	} else {
240	set statics [InterpStatics]
241	}
242	if {([::tcl::OptProcArgGiven -nested]) \
243	\|\| ([::tcl::OptProcArgGiven -nestedLoadOk]) } {
244	set nested [InterpNested]
245	} else {
246	set nested [Set [NestedOkName $slave]]
247	}
248	if {![::tcl::OptProcArgGiven -deleteHook]} {
249	set deleteHook [Set [DeleteHookName $slave]]
250	}
251	# we can now reconfigure :
252	InterpSetConfig $slave $accessPath $statics $nested $deleteHook
253	# auto_reset the slave (to completly synch the new access_path)
254	if {$doreset} {
255	if {[catch {::interp eval $slave {auto_reset}} msg]} {
256	Log $slave "auto_reset failed: $msg"
257	} else {
258	Log $slave "successful auto_reset" NOTICE
259	}
260	}
261	}
262	}
263	}
264
265
266	####
267	#
268	# Functions that actually implements the exported APIs
269	#
270	####
271
272
273	#
274	# safe::InterpCreate : doing the real job
275	#
276	# This procedure creates a safe slave and initializes it with the
277	# safe base aliases.
278	# NB: slave name must be simple alphanumeric string, no spaces,
279	# no (), no {},... {because the state array is stored as part of the name}
280	#
281	# Returns the slave name.
282	#
283	# Optional Arguments :
284	# + slave name : if empty, generated name will be used
285	# + access_path: path list controlling where load/source can occur,
286	# if empty: the master auto_path will be used.
287	# + staticsok : flag, if 0 :no static package can be loaded (load {} Xxx)
288	# if 1 :static packages are ok.
289	# + nestedok: flag, if 0 :no loading to sub-sub interps (load xx xx sub)
290	# if 1 : multiple levels are ok.
291
292	# use the full name and no indent so auto_mkIndex can find us
293	proc ::safe::InterpCreate {
294	slave
295	access_path
296	staticsok
297	nestedok
298	deletehook
299	} {
300	# Create the slave.
301	if {$slave ne ""} {
302	::interp create -safe $slave
303	} else {
304	# empty argument: generate slave name
305	set slave [::interp create -safe]
306	}
307	Log $slave "Created" NOTICE
308
309	# Initialize it. (returns slave name)
310	InterpInit $slave $access_path $staticsok $nestedok $deletehook
311	}
312
313
314	#
315	# InterpSetConfig (was setAccessPath) :
316	# Sets up slave virtual auto_path and corresponding structure
317	# within the master. Also sets the tcl_library in the slave
318	# to be the first directory in the path.
319	# Nb: If you change the path after the slave has been initialized
320	# you probably need to call "auto_reset" in the slave in order that it
321	# gets the right auto_index() array values.
322
323	proc ::safe::InterpSetConfig {slave access_path staticsok\
324	nestedok deletehook} {
325
326	# determine and store the access path if empty
327	if {$access_path eq ""} {
328	set access_path [uplevel \#0 set auto_path]
329	# Make sure that tcl_library is in auto_path
330	# and at the first position (needed by setAccessPath)
331	set where [lsearch -exact $access_path [info library]]
332	if {$where == -1} {
333	# not found, add it.
334	set access_path [concat [list [info library]] $access_path]
335	Log $slave "tcl_library was not in auto_path,\
336	added it to slave's access_path" NOTICE
337	} elseif {$where != 0} {
338	# not first, move it first
339	set access_path [concat [list [info library]]\
340	[lreplace $access_path $where $where]]
341	Log $slave "tcl_libray was not in first in auto_path,\
342	moved it to front of slave's access_path" NOTICE
343
344	}
345
346	# Add 1st level sub dirs (will searched by auto loading from tcl
347	# code in the slave using glob and thus fail, so we add them
348	# here so by default it works the same).
349	set access_path [AddSubDirs $access_path]
350	}
351
352	Log $slave "Setting accessPath=($access_path) staticsok=$staticsok\
353	nestedok=$nestedok deletehook=($deletehook)" NOTICE
354
355	# clear old autopath if it existed
356	set nname [PathNumberName $slave]
357	if {[Exists $nname]} {
358	set n [Set $nname]
359	for {set i 0} {$i<$n} {incr i} {
360	Unset [PathToken $i $slave]
361	}
362	}
363
364	# build new one
365	set slave_auto_path {}
366	set i 0
367	foreach dir $access_path {
368	Set [PathToken $i $slave] $dir
369	lappend slave_auto_path "\$[PathToken $i]"
370	incr i
371	}
372	Set $nname $i
373	Set [PathListName $slave] $access_path
374	Set [VirtualPathListName $slave] $slave_auto_path
375
376	Set [StaticsOkName $slave] $staticsok
377	Set [NestedOkName $slave] $nestedok
378	Set [DeleteHookName $slave] $deletehook
379
380	SyncAccessPath $slave
381	}
382
383	#
384	#
385	# FindInAccessPath:
386	# Search for a real directory and returns its virtual Id
387	# (including the "$")
388	proc ::safe::interpFindInAccessPath {slave path} {
389	set access_path [GetAccessPath $slave]
390	set where [lsearch -exact $access_path $path]
391	if {$where == -1} {
392	return -code error "$path not found in access path $access_path"
393	}
394	return "\$[PathToken $where]"
395	}
396
397	#
398	# addToAccessPath:
399	# add (if needed) a real directory to access path
400	# and return its virtual token (including the "$").
401	proc ::safe::interpAddToAccessPath {slave path} {
402	# first check if the directory is already in there
403	if {![catch {interpFindInAccessPath $slave $path} res]} {
404	return $res
405	}
406	# new one, add it:
407	set nname [PathNumberName $slave]
408	set n [Set $nname]
409	Set [PathToken $n $slave] $path
410
411	set token "\$[PathToken $n]"
412
413	Lappend [VirtualPathListName $slave] $token
414	Lappend [PathListName $slave] $path
415	Set $nname [expr {$n+1}]
416
417	SyncAccessPath $slave
418
419	return $token
420	}
421
422	# This procedure applies the initializations to an already existing
423	# interpreter. It is useful when you want to install the safe base
424	# aliases into a preexisting safe interpreter.
425	proc ::safe::InterpInit {
426	slave
427	access_path
428	staticsok
429	nestedok
430	deletehook
431	} {
432
433	# Configure will generate an access_path when access_path is
434	# empty.
435	InterpSetConfig $slave $access_path $staticsok $nestedok $deletehook
436
437	# These aliases let the slave load files to define new commands
438
439	# NB we need to add [namespace current], aliases are always
440	# absolute paths.
441	::interp alias $slave source {} [namespace current]::AliasSource $slave
442	::interp alias $slave load {} [namespace current]::AliasLoad $slave
443
444	# This alias lets the slave use the encoding names, convertfrom,
445	# convertto, and system, but not "encoding system <name>" to set
446	# the system encoding.
447
448	::interp alias $slave encoding {} [namespace current]::AliasEncoding \
449	$slave
450
451	# This alias lets the slave have access to a subset of the 'file'
452	# command functionality.
453
454	AliasSubset $slave file file dir.* join root.* ext.* tail \
455	path.* split
456
457	# This alias interposes on the 'exit' command and cleanly terminates
458	# the slave.
459
460	::interp alias $slave exit {} [namespace current]::interpDelete $slave
461
462	# The allowed slave variables already have been set
463	# by Tcl_MakeSafe(3)
464
465
466	# Source init.tcl into the slave, to get auto_load and other
467	# procedures defined:
468
469	if {[catch {::interp eval $slave\
470	{source [file join $tcl_library init.tcl]}} msg]} {
471	Log $slave "can't source init.tcl ($msg)"
472	error "can't source init.tcl into slave $slave ($msg)"
473	}
474
475	return $slave
476	}
477
478
479	# Add (only if needed, avoid duplicates) 1 level of
480	# sub directories to an existing path list.
481	# Also removes non directories from the returned list.
482	proc AddSubDirs {pathList} {
483	set res {}
484	foreach dir $pathList {
485	if {[file isdirectory $dir]} {
486	# check that we don't have it yet as a children
487	# of a previous dir
488	if {[lsearch -exact $res $dir]<0} {
489	lappend res $dir
490	}
491	foreach sub [glob -directory $dir -nocomplain *] {
492	if {([file isdirectory $sub]) \
493	&& ([lsearch -exact $res $sub]<0) } {
494	# new sub dir, add it !
495	lappend res $sub
496	}
497	}
498	}
499	}
500	return $res
501	}
502
503	# This procedure deletes a safe slave managed by Safe Tcl and
504	# cleans up associated state:
505
506	proc ::safe::interpDelete {slave} {
507
508	Log $slave "About to delete" NOTICE
509
510	# If the slave has a cleanup hook registered, call it.
511	# check the existance because we might be called to delete an interp
512	# which has not been registered with us at all
513	set hookname [DeleteHookName $slave]
514	if {[Exists $hookname]} {
515	set hook [Set $hookname]
516	if {![::tcl::Lempty $hook]} {
517	# remove the hook now, otherwise if the hook
518	# calls us somehow, we'll loop
519	Unset $hookname
520	if {[catch {{*}$hook $slave} err]} {
521	Log $slave "Delete hook error ($err)"
522	}
523	}
524	}
525
526	# Discard the global array of state associated with the slave, and
527	# delete the interpreter.
528
529	set statename [InterpStateName $slave]
530	if {[Exists $statename]} {
531	Unset $statename
532	}
533
534	# if we have been called twice, the interp might have been deleted
535	# already
536	if {[::interp exists $slave]} {
537	::interp delete $slave
538	Log $slave "Deleted" NOTICE
539	}
540
541	return
542	}
543
544	# Set (or get) the loging mecanism
545
546	proc ::safe::setLogCmd {args} {
547	variable Log
548	if {[llength $args] == 0} {
549	return $Log
550	} else {
551	if {[llength $args] == 1} {
552	set Log [lindex $args 0]
553	} else {
554	set Log $args
555	}
556	}
557	}
558
559	# internal variable
560	variable Log {}
561
562	# ------------------- END OF PUBLIC METHODS ------------
563
564
565	#
566	# sets the slave auto_path to the master recorded value.
567	# also sets tcl_library to the first token of the virtual path.
568	#
569	proc SyncAccessPath {slave} {
570	set slave_auto_path [Set [VirtualPathListName $slave]]
571	::interp eval $slave [list set auto_path $slave_auto_path]
572	Log $slave "auto_path in $slave has been set to $slave_auto_path"\
573	NOTICE
574	::interp eval $slave [list set tcl_library [lindex $slave_auto_path 0]]
575	}
576
577	# base name for storing all the slave states
578	# the array variable name for slave foo is thus "Sfoo"
579	# and for sub slave {foo bar} "Sfoo bar" (spaces are handled
580	# ok everywhere (or should))
581	# We add the S prefix to avoid that a slave interp called "Log"
582	# would smash our "Log" variable.
583	proc InterpStateName {slave} {
584	return "S$slave"
585	}
586
587	# Check that the given slave is "one of us"
588	proc IsInterp {slave} {
589	expr {[Exists [InterpStateName $slave]] && [::interp exists $slave]}
590	}
591
592	# returns the virtual token for directory number N
593	# if the slave argument is given,
594	# it will return the corresponding master global variable name
595	proc PathToken {n {slave ""}} {
596	if {$slave ne ""} {
597	return "[InterpStateName $slave](access_path,$n)"
598	} else {
599	# We need to have a ":" in the token string so
600	# [file join] on the mac won't turn it into a relative
601	# path.
602	return "p(:$n:)"
603	}
604	}
605	# returns the variable name of the complete path list
606	proc PathListName {slave} {
607	return "[InterpStateName $slave](access_path)"
608	}
609	# returns the variable name of the complete path list
610	proc VirtualPathListName {slave} {
611	return "[InterpStateName $slave](access_path_slave)"
612	}
613	# returns the variable name of the number of items
614	proc PathNumberName {slave} {
615	return "[InterpStateName $slave](access_path,n)"
616	}
617	# returns the staticsok flag var name
618	proc StaticsOkName {slave} {
619	return "[InterpStateName $slave](staticsok)"
620	}
621	# returns the nestedok flag var name
622	proc NestedOkName {slave} {
623	return "[InterpStateName $slave](nestedok)"
624	}
625	# Run some code at the namespace toplevel
626	proc Toplevel {args} {
627	namespace eval [namespace current] $args
628	}
629	# set/get values
630	proc Set {args} {
631	Toplevel set {*}$args
632	}
633	# lappend on toplevel vars
634	proc Lappend {args} {
635	Toplevel lappend {*}$args
636	}
637	# unset a var/token (currently just an global level eval)
638	proc Unset {args} {
639	Toplevel unset {*}$args
640	}
641	# test existance
642	proc Exists {varname} {
643	Toplevel info exists $varname
644	}
645	# short cut for access path getting
646	proc GetAccessPath {slave} {
647	Set [PathListName $slave]
648	}
649	# short cut for statics ok flag getting
650	proc StaticsOk {slave} {
651	Set [StaticsOkName $slave]
652	}
653	# short cut for getting the multiples interps sub loading ok flag
654	proc NestedOk {slave} {
655	Set [NestedOkName $slave]
656	}
657	# interp deletion storing hook name
658	proc DeleteHookName {slave} {
659	return [InterpStateName $slave](cleanupHook)
660	}
661
662	#
663	# translate virtual path into real path
664	#
665	proc TranslatePath {slave path} {
666	# somehow strip the namespaces 'functionality' out (the danger
667	# is that we would strip valid macintosh "../" queries... :
668	if {[string match "::" $path] \|\| [string match ".." $path]} {
669	error "invalid characters in path $path"
670	}
671	set n [expr {[Set [PathNumberName $slave]]-1}]
672	for {} {$n>=0} {incr n -1} {
673	# fill the token virtual names with their real value
674	set [PathToken $n] [Set [PathToken $n $slave]]
675	}
676	# replaces the token by their value
677	subst -nobackslashes -nocommands $path
678	}
679
680
681	# Log eventually log an error
682	# to enable error logging, set Log to {puts stderr} for instance
683	proc Log {slave msg {type ERROR}} {
684	variable Log
685	if {[info exists Log] && [llength $Log]} {
686	{*}$Log "$type for slave $slave : $msg"
687	}
688	}
689
690
691	# file name control (limit access to files/ressources that should be
692	# a valid tcl source file)
693	proc CheckFileName {slave file} {
694	# This used to limit what can be sourced to ".tcl" and forbid files
695	# with more than 1 dot and longer than 14 chars, but I changed that
696	# for 8.4 as a safe interp has enough internal protection already
697	# to allow sourcing anything. - hobbs
698
699	if {![file exists $file]} {
700	# don't tell the file path
701	error "no such file or directory"
702	}
703
704	if {![file readable $file]} {
705	# don't tell the file path
706	error "not readable"
707	}
708	}
709
710
711	# AliasSource is the target of the "source" alias in safe interpreters.
712
713	proc AliasSource {slave args} {
714
715	set argc [llength $args]
716	# Allow only "source filename"
717	if {$argc != 1} {
718	set msg "wrong # args: should be \"source fileName\""
719	Log $slave "$msg ($args)"
720	return -code error $msg
721	}
722	set file [lindex $args 0]
723
724	# get the real path from the virtual one.
725	if {[catch {set file [TranslatePath $slave $file]} msg]} {
726	Log $slave $msg
727	return -code error "permission denied"
728	}
729
730	# check that the path is in the access path of that slave
731	if {[catch {FileInAccessPath $slave $file} msg]} {
732	Log $slave $msg
733	return -code error "permission denied"
734	}
735
736	# do the checks on the filename :
737	if {[catch {CheckFileName $slave $file} msg]} {
738	Log $slave "$file:$msg"
739	return -code error $msg
740	}
741
742	# passed all the tests , lets source it:
743	if {[catch {::interp invokehidden $slave source $file} msg]} {
744	Log $slave $msg
745	return -code error "script error"
746	}
747	return $msg
748	}
749
750	# AliasLoad is the target of the "load" alias in safe interpreters.
751
752	proc AliasLoad {slave file args} {
753
754	set argc [llength $args]
755	if {$argc > 2} {
756	set msg "load error: too many arguments"
757	Log $slave "$msg ($argc) {$file $args}"
758	return -code error $msg
759	}
760
761	# package name (can be empty if file is not).
762	set package [lindex $args 0]
763
764	# Determine where to load. load use a relative interp path
765	# and {} means self, so we can directly and safely use passed arg.
766	set target [lindex $args 1]
767	if {$target ne ""} {
768	# we will try to load into a sub sub interp
769	# check that we want to authorize that.
770	if {![NestedOk $slave]} {
771	Log $slave "loading to a sub interp (nestedok)\
772	disabled (trying to load $package to $target)"
773	return -code error "permission denied (nested load)"
774	}
775
776	}
777
778	# Determine what kind of load is requested
779	if {$file eq ""} {
780	# static package loading
781	if {$package eq ""} {
782	set msg "load error: empty filename and no package name"
783	Log $slave $msg
784	return -code error $msg
785	}
786	if {![StaticsOk $slave]} {
787	Log $slave "static packages loading disabled\
788	(trying to load $package to $target)"
789	return -code error "permission denied (static package)"
790	}
791	} else {
792	# file loading
793
794	# get the real path from the virtual one.
795	if {[catch {set file [TranslatePath $slave $file]} msg]} {
796	Log $slave $msg
797	return -code error "permission denied"
798	}
799
800	# check the translated path
801	if {[catch {FileInAccessPath $slave $file} msg]} {
802	Log $slave $msg
803	return -code error "permission denied (path)"
804	}
805	}
806
807	if {[catch {::interp invokehidden\
808	$slave load $file $package $target} msg]} {
809	Log $slave $msg
810	return -code error $msg
811	}
812
813	return $msg
814	}
815
816	# FileInAccessPath raises an error if the file is not found in
817	# the list of directories contained in the (master side recorded) slave's
818	# access path.
819
820	# the security here relies on "file dirname" answering the proper
821	# result.... needs checking ?
822	proc FileInAccessPath {slave file} {
823
824	set access_path [GetAccessPath $slave]
825
826	if {[file isdirectory $file]} {
827	error "\"$file\": is a directory"
828	}
829	set parent [file dirname $file]
830
831	# Normalize paths for comparison since lsearch knows nothing of
832	# potential pathname anomalies.
833	set norm_parent [file normalize $parent]
834	foreach path $access_path {
835	lappend norm_access_path [file normalize $path]
836	}
837
838	if {[lsearch -exact $norm_access_path $norm_parent] == -1} {
839	error "\"$file\": not in access_path"
840	}
841	}
842
843	# This procedure enables access from a safe interpreter to only a subset of
844	# the subcommands of a command:
845
846	proc Subset {slave command okpat args} {
847	set subcommand [lindex $args 0]
848	if {[regexp $okpat $subcommand]} {
849	return [$command {*}$args]
850	}
851	set msg "not allowed to invoke subcommand $subcommand of $command"
852	Log $slave $msg
853	error $msg
854	}
855
856	# This procedure installs an alias in a slave that invokes "safesubset"
857	# in the master to execute allowed subcommands. It precomputes the pattern
858	# of allowed subcommands; you can use wildcards in the pattern if you wish
859	# to allow subcommand abbreviation.
860	#
861	# Syntax is: AliasSubset slave alias target subcommand1 subcommand2...
862
863	proc AliasSubset {slave alias target args} {
864	set pat ^(; set sep ""
865	foreach sub $args {
866	append pat $sep$sub
867	set sep \|
868	}
869	append pat )\$
870	::interp alias $slave $alias {}\
871	[namespace current]::Subset $slave $target $pat
872	}
873
874	# AliasEncoding is the target of the "encoding" alias in safe interpreters.
875
876	proc AliasEncoding {slave args} {
877
878	set argc [llength $args]
879
880	set okpat "^(name.\|convert.)\$"
881	set subcommand [lindex $args 0]
882
883	if {[regexp $okpat $subcommand]} {
884	return [::interp invokehidden $slave encoding {*}$args]
885	}
886
887	if {[string first $subcommand system] == 0} {
888	if {$argc == 1} {
889	# passed all the tests , lets source it:
890	if {[catch {::interp invokehidden \
891	$slave encoding system} msg]} {
892	Log $slave $msg
893	return -code error "script error"
894	}
895	} else {
896	set msg "wrong # args: should be \"encoding system\""
897	Log $slave $msg
898	error $msg
899	}
900	} else {
901	set msg "wrong # args: should be \"encoding option ?arg ...?\""
902	Log $slave $msg
903	error $msg
904	}
905
906	return $msg
907	}
908
909	}

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source: data/Media/tcl/safe.tcl @ 5076

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