added a basic outline of the MTFS protocol

MTFS/OpenOS/usr/bin/exportfs.lua

@@ -0,0 +1,17 @@
+local fsproxy = require "fsproxy"
+local rpc = require "rpc"
+local fs = require "filesystem"
+
+local tA = {...}
+if #tA < 1 then
+ print("Usage: exportfs <directory> [directory] ...")
+ return
+end
+
+for k,v in pairs(tA) do
+ local px = fsproxy.new(v)
+ for l,m in pairs(px) do
+  rpc.register("fs_"..v.."_"..l,m)
+ end
+ print(v)
+end

MTFS/OpenOS/usr/bin/importfs.lua

@@ -0,0 +1,60 @@
+local computer = require "computer"
+local fs = require "filesystem"
+local rpc = require "rpc"
+local tA = {...}
+local rpath, lpath = tA[1], tA[2], tA[3]
+
+if #tA < 2 then
+ print("Usage: importfs <remote path> <local path>")
+ return
+end
+
+local function parsePath(path)
+ return path:match("(.+):(.+)")
+end
+
+local host, saddr = parsePath(rpath)
+local px = rpc.proxy(host,"fs_"..saddr.."_")
+local mc = 0
+for k,v in pairs(px) do
+ mc = mc + 1
+end
+if mc < 1 then
+ error("no such remote filesystem: "..rpath)
+end
+local statcache = {}
+px.address = rpath
+if px.dirstat then -- use single call for file info
+ function px.list(path)
+  local t,e = px.dirstat(path)
+  if not t then return nil,e end
+  local rt = {}
+  for k,v in pairs(t) do
+   rt[#rt+1] = k
+   statcache[fs.canonical("/"..path.."/"..k)] = {computer.uptime(),v[1],v[2],v[3]}
+  end
+  return rt
+ end
+ local oid, osize, olm = px.isDirectory, px.size, px.lastModified
+ local function gce(p,n)
+  for k,v in pairs(statcache) do
+   if computer.uptime() > v[1] + 1 then
+    statcache[k] = nil
+   end
+  end
+  local ci = statcache["/"..fs.canonical(p)]
+  if ci then
+   return ci[3]
+  end
+ end
+ function px.isDirectory(path)
+  return gce(path, 2) or oid(path)
+ end
+ function px.size(path)
+  return gce(path, 3) or osize(path)
+ end
+ function px.lastModified(path)
+  return gce(path, 4) or olm(path)
+ end
+end
+fs.mount(px, lpath)

MTFS/OpenOS/usr/lib/fsproxy.lua

@@ -0,0 +1,111 @@
+local fs = require "filesystem"
+local fsproxy = {}
+local fsfunc = {}
+
+local function sanitisePath(path)
+ local pt = {}
+ for s in path:gmatch("([^/]+)") do
+  if s == ".." then
+   pt[#pt] = nil
+  elseif s == "." then
+  else
+   pt[#pt+1] = s
+  end
+ end
+ return table.concat(pt,"/")
+end
+
+
+function fsproxy.new(path,wp) -- string boolean -- table -- Returns a proxy object for a given path that acts like a filesystem.
+ local cpath = fs.canonical(path).."/"
+ if not fs.exists(path) or not fs.isDirectory(path) then
+  error("invalid directory")
+ end
+ local originalProxy = fs.get(path)
+ local proxy = {}
+ for k,v in pairs(originalProxy) do
+  if type(v) ~= "table" then
+   proxy[k] = v
+  end
+ end
+ local handles = {}
+ function proxy.isReadOnly()
+  return originalProxy.isReadOnly()
+ end
+ function proxy.getLabel()
+  return originalProxy.getLabel()
+ end
+ function proxy.spaceUsed()
+  return originalProxy.spaceUsed()
+ end
+ function proxy.spaceTotal()
+  return originalProxy.spaceTotal()
+ end
+ function proxy.exists(path)
+  return fs.exists(cpath..sanitisePath(path))
+ end
+ function proxy.isDirectory(path)
+  return fs.isDirectory(cpath..sanitisePath(path))
+ end
+ function proxy.makeDirectory(path)
+  if wp then return false, "read-only filesystem" end
+  return fs.makeDirectory(cpath..sanitisePath(path))
+ end
+ function proxy.rename(from, to)
+  if wp then return false, "read-only filesystem" end
+  return fs.rename(cpath..sanitisePath(from),cpath..sanitisePath(to))
+ end
+ function proxy.list(path)
+  local rt = {}
+  local iter, err = fs.list(cpath..sanitisePath(path))
+  if not iter then return nil, err end
+  for name in iter do
+   rt[#rt+1] = name
+  end
+  return rt
+ end
+ function proxy.lastModified(path)
+  return fs.lastModified(cpath..sanitisePath(path))
+ end
+ function proxy.remove(path)
+  if wp then return false, "read-only filesystem" end
+  return fs.remove(cpath..sanitisePath(path))
+ end
+ function proxy.size(path)
+  return fs.size(cpath..sanitisePath(path))
+ end
+
+ function proxy.dirstat(path) -- bundle the metadata about files into the listing to reduce round trips
+  local rt = {}
+  local dp = cpath..sanitisePath(path).."/"
+  local iter, err = fs.list(dp)
+  if not iter then return nil, err end
+  for name in iter do
+   rt[name] = {fs.isDirectory(dp..name), fs.size(dp..name), fs.lastModified(dp..name)}
+  end
+  return rt
+ end
+ 
+ function proxy.open(path,mode)
+  if wp and mode:find("[wa]") then return false, "read-only filesystem" end
+  local h, e = fs.open(cpath..sanitisePath(path),mode)
+  if not h then return h, e end
+  handles[#handles+1] = h
+  return #handles
+ end
+ function proxy.seek(handle, whence, offset)
+  return handles[handle]:seek(whence,offset)
+ end
+ function proxy.write(handle, data)
+  return handles[handle]:write(data)
+ end
+ function proxy.read(handle, count)
+  return handles[handle]:read(count)
+ end
+ function proxy.close(handle)
+  return handles[handle]:close()
+ end
+ return proxy
+end
+
+return fsproxy

MTFS/README.md

@@ -0,0 +1,44 @@
+# MTFS
+
+MTFS is, in effect, a standardised set of names for function endpoints implementing the [API of an OpenComputers filesystem component](https://ocdoc.cil.li/component:filesystem), over Minitel RPC.
+
+## Function names
+
+Names for filesystem "component" functions should follow the form `fs_<identifier>_<function>`, so, for example, `fs_/usr_isDirectory`.
+
+## Functions
+
+Unless otherwise specified, functions should be inherited from, or implemented to emulate, an [OpenComputers filesystem component](https://ocdoc.cil.li/component:filesystem). More specifically:
+
+- spaceUsed
+- seek
+- makeDirectory
+- exists
+- isReadOnly
+- write
+- spaceTotal
+- isDirectory
+- rename
+- list
+- lastModified
+- getLabel
+- setLabel
+- remove
+- size
+- open
+- read
+- write
+- close
+
+### Optional extensions
+
+#### dirstat
+
+An optional extra function, `dirstat`, may be implemented on the server side to allow clients to access directory listings with less RPC calls; it should return data in a Lua table of the following structure:
+
+```
+{
+ [filename: string] = {isDirectory: boolean, size: boolean, lastModified: number},
+ ...
+}
+```

programs.cfg

@@ -203,4 +203,18 @@
   authors = "Izaya",
   repo = "tree/master/"
  },
+ ["mtfs"] = {
+  files = {
+   ["master/MTFS/OpenOS/usr/bin/importfs.lua"] = "/bin",
+   ["master/MTFS/OpenOS/usr/bin/exportfs.lua"] = "/bin",
+   ["master/MTFS/OpenOS/usr/lib/fsproxy.lua"] = "/lib",
+  },
+  dependencies = {
+   ["mtrpc"] = ""
+  },
+  name = "Minitel Remote Filesystem",
+  description = "Utilities for accessing filesystems over Minitel RPC",
+  authors = "Izaya",
+  repo = "tree/master/"
+ },
 }