# safe.tcl --

#

# This file provide a safe loading/sourcing mechanism for safe interpreters.

# It implements a virtual path mecanism to hide the real pathnames from the

# slave. It runs in a master interpreter and sets up data structure and

# aliases that will be invoked when used from a slave interpreter.

# 

# See the safe.n man page for details.

#

# Copyright (c) 1996-1997 Sun Microsystems, Inc.

#

# See the file "license.terms" for information on usage and redistribution

# of this file, and for a DISCLAIMER OF ALL WARRANTIES.

#

# RCS: @(#) $Id: safe.tcl,v 1.9.2.3 2005/07/22 21:59:41 dgp Exp $

#

# The implementation is based on namespaces. These naming conventions

# are followed:

# Private procs starts with uppercase.

# Public  procs are exported and starts with lowercase

#

# Needed utilities package

package require opt 0.4.1;

# Create the safe namespace

namespace eval ::safe {

    # Exported API:

    namespace export interpCreate interpInit interpConfigure interpDelete \

	    interpAddToAccessPath interpFindInAccessPath setLogCmd

    ####

    #

    # Setup the arguments parsing

    #

    ####

    # Make sure that our temporary variable is local to this

    # namespace.  [Bug 981733]

    variable temp

    # Share the descriptions

    set temp [::tcl::OptKeyRegister {

	{-accessPath -list {} "access path for the slave"}

	{-noStatics "prevent loading of statically linked pkgs"}

	{-statics true "loading of statically linked pkgs"}

	{-nestedLoadOk "allow nested loading"}

	{-nested false "nested loading"}

	{-deleteHook -script {} "delete hook"}

    }]

    # create case (slave is optional)

    ::tcl::OptKeyRegister {

	{?slave? -name {} "name of the slave (optional)"}

    } ::safe::interpCreate

    # adding the flags sub programs to the command program

    # (relying on Opt's internal implementation details)

    lappend ::tcl::OptDesc(::safe::interpCreate) $::tcl::OptDesc($temp)

    # init and configure (slave is needed)

    ::tcl::OptKeyRegister {

	{slave -name {} "name of the slave"}

    } ::safe::interpIC

    # adding the flags sub programs to the command program

    # (relying on Opt's internal implementation details)

    lappend ::tcl::OptDesc(::safe::interpIC) $::tcl::OptDesc($temp)

    # temp not needed anymore

    ::tcl::OptKeyDelete $temp

    # Helper function to resolve the dual way of specifying staticsok

    # (either by -noStatics or -statics 0)

    proc InterpStatics {} {

	foreach v {Args statics noStatics} {

	    upvar $v $v

	}

	set flag [::tcl::OptProcArgGiven -noStatics];

	if {$flag && (!$noStatics == !$statics) 

	          && ([::tcl::OptProcArgGiven -statics])} {

	    return -code error\

		    "conflicting values given for -statics and -noStatics"

	}

	if {$flag} {

	    return [expr {!$noStatics}]

	} else {

	    return $statics

	}

    }

    # Helper function to resolve the dual way of specifying nested loading

    # (either by -nestedLoadOk or -nested 1)

    proc InterpNested {} {

	foreach v {Args nested nestedLoadOk} {

	    upvar $v $v

	}

	set flag [::tcl::OptProcArgGiven -nestedLoadOk];

	# note that the test here is the opposite of the "InterpStatics"

	# one (it is not -noNested... because of the wanted default value)

	if {$flag && (!$nestedLoadOk != !$nested) 

	          && ([::tcl::OptProcArgGiven -nested])} {

	    return -code error\

		    "conflicting values given for -nested and -nestedLoadOk"

	}

	if {$flag} {

	    # another difference with "InterpStatics"

	    return $nestedLoadOk

	} else {

	    return $nested

	}

    }

    ####

    #

    #  API entry points that needs argument parsing :

    #

    ####

    # Interface/entry point function and front end for "Create"

    proc interpCreate {args} {

	set Args [::tcl::OptKeyParse ::safe::interpCreate $args]

	InterpCreate $slave $accessPath \

		[InterpStatics] [InterpNested] $deleteHook

    }

    proc interpInit {args} {

	set Args [::tcl::OptKeyParse ::safe::interpIC $args]

	if {![::interp exists $slave]} {

	    return -code error "\"$slave\" is not an interpreter"

	}

	InterpInit $slave $accessPath \

		[InterpStatics] [InterpNested] $deleteHook;

    }

    proc CheckInterp {slave} {

	if {![IsInterp $slave]} {

	    return -code error \

		    "\"$slave\" is not an interpreter managed by ::safe::"

	}

    }

    # Interface/entry point function and front end for "Configure"

    # This code is awfully pedestrian because it would need

    # more coupling and support between the way we store the

    # configuration values in safe::interp's and the Opt package

    # Obviously we would like an OptConfigure

    # to avoid duplicating all this code everywhere. -> TODO

    # (the app should share or access easily the program/value

    #  stored by opt)

    # This is even more complicated by the boolean flags with no values

    # that we had the bad idea to support for the sake of user simplicity

    # in create/init but which makes life hard in configure...

    # So this will be hopefully written and some integrated with opt1.0

    # (hopefully for tcl8.1 ?)

    proc interpConfigure {args} {

	switch [llength $args] {

	    1 {

		# If we have exactly 1 argument

		# the semantic is to return all the current configuration

		# We still call OptKeyParse though we know that "slave"

		# is our given argument because it also checks

		# for the "-help" option.

		set Args [::tcl::OptKeyParse ::safe::interpIC $args]

		CheckInterp $slave

		set res {}

		lappend res [list -accessPath [Set [PathListName $slave]]]

		lappend res [list -statics    [Set [StaticsOkName $slave]]]

		lappend res [list -nested     [Set [NestedOkName $slave]]]

		lappend res [list -deleteHook [Set [DeleteHookName $slave]]]

		join $res

	    }

	    2 {

		# If we have exactly 2 arguments

		# the semantic is a "configure get"

		::tcl::Lassign $args slave arg

		# get the flag sub program (we 'know' about Opt's internal

		# representation of data)

		set desc [lindex [::tcl::OptKeyGetDesc ::safe::interpIC] 2]

		set hits [::tcl::OptHits desc $arg]

                if {$hits > 1} {

                    return -code error [::tcl::OptAmbigous $desc $arg]

                } elseif {$hits == 0} {

                    return -code error [::tcl::OptFlagUsage $desc $arg]

                }

		CheckInterp $slave

		set item [::tcl::OptCurDesc $desc]

		set name [::tcl::OptName $item]

		switch -exact -- $name {

		    -accessPath {

			return [list -accessPath [Set [PathListName $slave]]]

		    }

		    -statics {

			return [list -statics    [Set [StaticsOkName $slave]]]

		    }

		    -nested {

			return [list -nested     [Set [NestedOkName $slave]]]

		    }

		    -deleteHook {

			return [list -deleteHook [Set [DeleteHookName $slave]]]

		    }

		    -noStatics {

			# it is most probably a set in fact

			# but we would need then to jump to the set part

			# and it is not *sure* that it is a set action

			# that the user want, so force it to use the

			# unambigous -statics ?value? instead:

			return -code error\

				"ambigous query (get or set -noStatics ?)\

				use -statics instead"

		    }

		    -nestedLoadOk {

			return -code error\

				"ambigous query (get or set -nestedLoadOk ?)\

				use -nested instead"

		    }

		    default {

			return -code error "unknown flag $name (bug)"

		    }

		}

	    }

	    default {

		# Otherwise we want to parse the arguments like init and create

		# did

		set Args [::tcl::OptKeyParse ::safe::interpIC $args]

		CheckInterp $slave

		# Get the current (and not the default) values of

		# whatever has not been given:

		if {![::tcl::OptProcArgGiven -accessPath]} {

		    set doreset 1

		    set accessPath [Set [PathListName $slave]]

		} else {

		    set doreset 0

		}

		if {(![::tcl::OptProcArgGiven -statics]) \

			&& (![::tcl::OptProcArgGiven -noStatics]) } {

		    set statics    [Set [StaticsOkName $slave]]

		} else {

		    set statics    [InterpStatics]

		}

		if {([::tcl::OptProcArgGiven -nested]) \

			|| ([::tcl::OptProcArgGiven -nestedLoadOk]) } {

		    set nested     [InterpNested]

		} else {

		    set nested     [Set [NestedOkName $slave]]

		}

		if {![::tcl::OptProcArgGiven -deleteHook]} {

		    set deleteHook [Set [DeleteHookName $slave]]

		}

		# we can now reconfigure :

		InterpSetConfig $slave $accessPath $statics $nested $deleteHook

		# auto_reset the slave (to completly synch the new access_path)

		if {$doreset} {

		    if {[catch {::interp eval $slave {auto_reset}} msg]} {

			Log $slave "auto_reset failed: $msg"

		    } else {

			Log $slave "successful auto_reset" NOTICE

		    }

		}

	    }

	}

    }

    ####

    #

    #  Functions that actually implements the exported APIs

    #

    ####

    #

    # safe::InterpCreate : doing the real job

    #

    # This procedure creates a safe slave and initializes it with the

    # safe base aliases.

    # NB: slave name must be simple alphanumeric string, no spaces,

    # no (), no {},...  {because the state array is stored as part of the name}

    #

    # Returns the slave name.

    #

    # Optional Arguments : 

    # + slave name : if empty, generated name will be used

    # + access_path: path list controlling where load/source can occur,

    #                if empty: the master auto_path will be used.

    # + staticsok  : flag, if 0 :no static package can be loaded (load {} Xxx)

    #                      if 1 :static packages are ok.

    # + nestedok: flag, if 0 :no loading to sub-sub interps (load xx xx sub)

    #                      if 1 : multiple levels are ok.

    # use the full name and no indent so auto_mkIndex can find us

    proc ::safe::InterpCreate {

	slave 

	access_path

	staticsok

	nestedok

	deletehook

    } {

	# Create the slave.

	if {$slave ne ""} {

	    ::interp create -safe $slave

	} else {

	    # empty argument: generate slave name

	    set slave [::interp create -safe]

	}

	Log $slave "Created" NOTICE

	# Initialize it. (returns slave name)

	InterpInit $slave $access_path $staticsok $nestedok $deletehook

    }

    #

    # InterpSetConfig (was setAccessPath) :

    #    Sets up slave virtual auto_path and corresponding structure

    #    within the master. Also sets the tcl_library in the slave

    #    to be the first directory in the path.

    #    Nb: If you change the path after the slave has been initialized

    #    you probably need to call "auto_reset" in the slave in order that it

    #    gets the right auto_index() array values.

    proc ::safe::InterpSetConfig {slave access_path staticsok\

	    nestedok deletehook} {

	# determine and store the access path if empty

	if {$access_path eq ""} {

	    set access_path [uplevel \#0 set auto_path]

	    # Make sure that tcl_library is in auto_path

	    # and at the first position (needed by setAccessPath)

	    set where [lsearch -exact $access_path [info library]]

	    if {$where == -1} {

		# not found, add it.

		set access_path [concat [list [info library]] $access_path]

		Log $slave "tcl_library was not in auto_path,\

			added it to slave's access_path" NOTICE

	    } elseif {$where != 0} {

		# not first, move it first

		set access_path [concat [list [info library]]\

			[lreplace $access_path $where $where]]

		Log $slave "tcl_libray was not in first in auto_path,\

			moved it to front of slave's access_path" NOTICE

	    }

	    # Add 1st level sub dirs (will searched by auto loading from tcl

	    # code in the slave using glob and thus fail, so we add them

	    # here so by default it works the same).

	    set access_path [AddSubDirs $access_path]

	}

	Log $slave "Setting accessPath=($access_path) staticsok=$staticsok\

		nestedok=$nestedok deletehook=($deletehook)" NOTICE

	# clear old autopath if it existed

	set nname [PathNumberName $slave]

	if {[Exists $nname]} {

	    set n [Set $nname]

	    for {set i 0} {$i<$n} {incr i} {

		Unset [PathToken $i $slave]

	    }

	}

	# build new one

	set slave_auto_path {}

	set i 0

	foreach dir $access_path {

	    Set [PathToken $i $slave] $dir

	    lappend slave_auto_path "\$[PathToken $i]"

	    incr i

	}

	Set $nname $i

	Set [PathListName $slave] $access_path

	Set [VirtualPathListName $slave] $slave_auto_path

	Set [StaticsOkName $slave] $staticsok

	Set [NestedOkName $slave] $nestedok

	Set [DeleteHookName $slave] $deletehook

	SyncAccessPath $slave

    }

    #

    #

    # FindInAccessPath:

    #    Search for a real directory and returns its virtual Id

    #    (including the "$")

proc ::safe::interpFindInAccessPath {slave path} {

	set access_path [GetAccessPath $slave]

	set where [lsearch -exact $access_path $path]

	if {$where == -1} {

	    return -code error "$path not found in access path $access_path"

	}

	return "\$[PathToken $where]"

    }

    #

    # addToAccessPath:

    #    add (if needed) a real directory to access path

    #    and return its virtual token (including the "$").

proc ::safe::interpAddToAccessPath {slave path} {

	# first check if the directory is already in there

	if {![catch {interpFindInAccessPath $slave $path} res]} {

	    return $res

	}

	# new one, add it:

	set nname [PathNumberName $slave]

	set n [Set $nname]

	Set [PathToken $n $slave] $path

	set token "\$[PathToken $n]"

	Lappend [VirtualPathListName $slave] $token

	Lappend [PathListName $slave] $path

	Set $nname [expr {$n+1}]

	SyncAccessPath $slave

	return $token

    }

    # This procedure applies the initializations to an already existing

    # interpreter. It is useful when you want to install the safe base

    # aliases into a preexisting safe interpreter.

    proc ::safe::InterpInit {

	slave 

	access_path

	staticsok

	nestedok

	deletehook

    } {

	# Configure will generate an access_path when access_path is

	# empty.

	InterpSetConfig $slave $access_path $staticsok $nestedok $deletehook

	# These aliases let the slave load files to define new commands

	# NB we need to add [namespace current], aliases are always

	# absolute paths.

	::interp alias $slave source {} [namespace current]::AliasSource $slave

	::interp alias $slave load {} [namespace current]::AliasLoad $slave

	# This alias lets the slave use the encoding names, convertfrom,

	# convertto, and system, but not "encoding system <name>" to set

	# the system encoding.

	::interp alias $slave encoding {} [namespace current]::AliasEncoding \

		$slave

	# This alias lets the slave have access to a subset of the 'file'

	# command functionality.

	AliasSubset $slave file file dir.* join root.* ext.* tail \

		path.* split

	# This alias interposes on the 'exit' command and cleanly terminates

	# the slave.

	::interp alias $slave exit {} [namespace current]::interpDelete $slave

	# The allowed slave variables already have been set

	# by Tcl_MakeSafe(3)

	# Source init.tcl into the slave, to get auto_load and other

	# procedures defined:

	# We don't try to use the -rsrc on the mac because it would get

	# confusing if you would want to customize init.tcl

	# for a given set of safe slaves, on all the platforms

	# you just need to give a specific access_path and

	# the mac should be no exception. As there is no

	# obvious full "safe ressources" design nor implementation

	# for the mac, safe interps there will just don't

	# have that ability. (A specific app can still reenable

	# that using custom aliases if they want to).

	# It would also make the security analysis and the Safe Tcl security

	# model platform dependant and thus more error prone.

	if {[catch {::interp eval $slave\

		{source [file join $tcl_library init.tcl]}} msg]} {

	    Log $slave "can't source init.tcl ($msg)"

	    error "can't source init.tcl into slave $slave ($msg)"

	}

	return $slave

    }

    # Add (only if needed, avoid duplicates) 1 level of

    # sub directories to an existing path list.

    # Also removes non directories from the returned list.

    proc AddSubDirs {pathList} {

	set res {}

	foreach dir $pathList {

	    if {[file isdirectory $dir]} {

		# check that we don't have it yet as a children

		# of a previous dir

		if {[lsearch -exact $res $dir]<0} {

		    lappend res $dir

		}

		foreach sub [glob -directory $dir -nocomplain *] {

		    if {([file isdirectory $sub]) \

			    && ([lsearch -exact $res $sub]<0) } {

			# new sub dir, add it !

	                lappend res $sub

	            }

		}

	    }

	}

	return $res

    }

    # This procedure deletes a safe slave managed by Safe Tcl and

    # cleans up associated state:

proc ::safe::interpDelete {slave} {

        Log $slave "About to delete" NOTICE

	# If the slave has a cleanup hook registered, call it.

	# check the existance because we might be called to delete an interp

	# which has not been registered with us at all

	set hookname [DeleteHookName $slave]

	if {[Exists $hookname]} {

	    set hook [Set $hookname]

	    if {![::tcl::Lempty $hook]} {