1 files changed, 148 insertions, 0 deletions
diff --git a/tex/context/base/luat-iop.lua b/tex/context/base/luat-iop.lua
new file mode 100644
index 000000000..e5722d2bd
--- /dev/null
+++ b/tex/context/base/luat-iop.lua
@@ -0,0 +1,148 @@
+if not modules then modules = { } end modules ['luat-iop'] = {
+    version   = 1.001,
+    comment   = "companion to luat-lib.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- this paranoid stuff in web2c ... we cannot hook checks into the
+-- input functions because one can always change the callback but
+-- we can feed back specific patterns and paths into the next
+-- mechanism
+
+local lower, find, sub = string.lower, string.find, string.sub
+
+local ioinp = io.inp if not ioinp then ioinp = { } io.inp = ioinp end
+local ioout = io.out if not ioout then ioout = { } io.out = ioout end
+
+ioinp.modes, ioout.modes = { }, { }  -- functions
+
+local inp_blocked, inp_permitted = { }, { }
+local out_blocked, out_permitted = { }, { }
+
+local function i_inhibit(name) inp_blocked  [#inp_blocked  +1] = name end
+local function o_inhibit(name) out_blocked  [#out_blocked  +1] = name end
+local function i_permit (name) inp_permitted[#inp_permitted+1] = name end
+local function o_permit (name) out_permitted[#out_permitted+1] = name end
+
+ioinp.inhibit, ioinp.permit = i_inhibit, o_permit
+ioout.inhibit, ioout.permit = o_inhibit, o_permit
+
+local blocked_openers = { } -- *.open(name,method)
+
+function io.register_opener(func)
+    blocked_openers[#blocked_openers+1] = func
+end
+
+local function checked(name,blocked,permitted)
+    local n = lower(name)
+    for _,b in next, blocked do
+        if find(n,b) then
+            for _,p in next, permitted do
+                if find(n,p) then
+                    return true
+                end
+            end
+            return false
+        end
+    end
+    return true
+end
+
+function io.finalize_openers(func)
+    if #out_blocked > 0 or #inp_blocked > 0 then
+        local open = func -- why not directly?
+        return function(name,method)
+            if method and find(method,'[wa]') then
+                if #out_blocked > 0 and not checked(name,out_blocked,out_permitted) then
+                    -- print("writing to " .. name .. " is not permitted")
+                    return nil
+                end
+            else
+                if #inp_blocked > 0 and not checked(name,inp_blocked,inp_permitted) then
+                    -- print("reading from " .. name .. " is not permitted")
+                    return nil
+                end
+            end
+            return open(name,method)
+        end
+    else
+        return func
+    end
+end
+
+--~ io.inp.inhibit('^%.')
+--~ io.inp.inhibit('^/etc')
+--~ io.inp.inhibit('/windows/')
+--~ io.inp.inhibit('/winnt/')
+--~ io.inp.permit('c:/windows/wmsetup.log')
+
+--~ io.open = io.finalize_openers(io.open)
+
+--~ f = io.open('.tex')                   print(f)
+--~ f = io.open('tufte.tex')              print(f)
+--~ f = io.open('t:/sources/tufte.tex')   print(f)
+--~ f = io.open('/etc/passwd')            print(f)
+--~ f = io.open('c:/windows/crap.log')    print(f)
+--~ f = io.open('c:/windows/wmsetup.log') print(f)
+
+local inpout = { 'inp', 'out' }
+
+function io.set_opener_modes(i,o)
+    local first = sub(i,1,1)
+    for k=1,#inpout do
+        local iov = io[inpout[k]]
+        local f = iov[i] or iov[first]
+        if f then f() end
+    end
+    io.open = io.finalize_openers(io.open)
+end
+
+-- restricted
+
+function ioinp.modes.restricted()
+    i_inhibit('^%.[%a]')
+end
+
+function ioout.modes.restricted()
+    o_inhibit('^%.[%a]')
+end
+
+-- paranoid
+
+function ioinp.modes.paranoid()
+    i_inhibit('.*')
+    i_inhibit('%.%.')
+    i_permit('^%./')
+    i_permit('[^/]')
+    resolvers.do_with_path('TEXMF',i_permit)
+end
+
+function ioout.modes.paranoid()
+    o_inhibit('.*')
+    resolvers.do_with_path('TEXMFOUTPUT',o_permit)
+end
+
+-- handy
+
+function ioinp.modes.handy()
+    i_inhibit('%.%.')
+    if os.type == 'windows' then
+        i_inhibit('/windows/')
+        i_inhibit('/winnt/')
+    else
+        i_inhibit('^/etc')
+    end
+end
+
+function ioout.modes.handy()
+    o_inhibit('.*')
+    o_permit('%./')
+    o_permit('^%./')
+    o_permit('[^/]')
+end
+
+--~ io.set_opener_modes('p','p')
+--~ io.set_opener_modes('r','r')
+--~ io.set_opener_modes('h','h')