Data connection is now passive. Even minimum FTP servers are usable.

1 files changed, 73 insertions, 62 deletions

diff --git a/src/ftp.lua b/src/ftp.lua
index b817356..a9dac71 100644
--- a/src/ftp.lua
+++ b/src/ftp.lua
@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------------
--- Simple FTP support for the Lua language using the LuaSocket toolkit.
+-- Simple FTP support for the Lua language using the LuaSocket 1.2 toolkit.
 -- Author: Diego Nehab
 -- Date: 26/12/2000
 -- Conforming to: RFC 959
@@ -170,20 +170,22 @@ end
 -- Input
 --   file: abolute path to file
 -- Returns
---   file: filename
---   path: table with directories to reach filename
---   isdir: is it a directory or a file
+--   a table with the following fields
+--     name: filename
+--     path: directory to file
+--     isdir: is it a directory?
 -----------------------------------------------------------------------------
 local split_path  = function(file)
-        local path = {}
-        local isdir
-        file = file or "/"
-        -- directory ends with a '/'
-        _,_, isdir = strfind(file, "([/])$")
-        gsub(file, "([^/]+)", function (dir) tinsert(%path, dir) end)
-        if not isdir then file = tremove(path)
-        else file = nil end
-        return file, path, isdir
+    local parsed = {}
+    file = gsub(file, "(/)$", function(i) %parsed.isdir = i end)
+    if not parsed.isdir then
+        file = gsub(file, "([^/]+)$", function(n) %parsed.name = n end)
+    end
+    file = gsub(file, "/$", "")
+    file = gsub(file, "^/", "")
+    if file == "" then file = nil end
+    parsed.path = file
+    if parsed.path or parsed.name or parsed.isdir then return parsed end
 end
 
 -----------------------------------------------------------------------------
@@ -226,40 +228,44 @@ end
 -- Change to target directory
 -- Input
 --   control: socket for control connection with server
---   path: array with directories in order
+--   path: directory to change to
 -- Returns
 --   code: nil if error
 --   answer: server answer or error message
 -----------------------------------------------------------------------------
 local cwd = function(control, path)
         local code, answer = 250, "Home directory used"
-        for i = 1, getn(path) do
-                code, answer = %try_command(control, "cwd", path[i], {250})
-                if not code then return nil, answer end
+        if path then
+                code, answer = %try_command(control, "cwd", path, {250})
         end
         return code, answer
 end
 
 -----------------------------------------------------------------------------
--- Start data connection with server
+-- Change to target directory
 -- Input
---   control: control connection with server
+--   control: socket for control connection with server
 -- Returns
---   data: socket for data connection with server, nil if error
---   answer: server answer or error message
------------------------------------------------------------------------------
-local start_dataconnection = function(control)
-        -- ask for passive data connection
-        local code, answer = %try_command(control, "pasv", nil, {227})
-        if not code then return nil, answer end
-        -- get data connection parameters from server reply
-        local host, port = %get_pasv(answer)
-        if not host or not port then return nil, answer end
-        -- start data connection with given parameters
-        local data, err = connect(host, port)
-        if not data then return nil, err end
-        data:timeout(%TIMEOUT)
-        return data
+--   server: server socket bound to local address, nil if error
+--   answer: error message if any
+-----------------------------------------------------------------------------
+local port = function(control)
+        local code, answer
+        local server, ctl_ip
+        ctl_ip, answer = control:getsockname()
+        server, answer = bind(ctl_ip, 0)
+        server:timeout(%TIMEOUT)
+        local ip, p, ph, pl
+        ip, p = server:getsockname()
+        pl = mod(p, 256)
+        ph = (p - pl)/256
+    local arg = gsub(format("%s,%d,%d", ip, ph, pl), "%.", ",")
+        code, answer = %try_command(control, "port", arg, {200})
+        if not code then 
+                control:close()
+                server:close()
+                return nil, answer
+        else return server end
 end
 
 -----------------------------------------------------------------------------
@@ -281,22 +287,21 @@ end
 -- Retrieves file or directory listing
 -- Input
 --   control: control connection with server
---   data: data connection with server
+--   server: server socket bound to local address
 --   file: file name under current directory
 --   isdir: is file a directory name?
 -- Returns
 --   file: string with file contents, nil if error
 --   answer: server answer or error message
 -----------------------------------------------------------------------------
-local retrieve_file = function(control, data, file, isdir)
+local retrieve_file = function(control, server, file, isdir)
+        local data
         -- ask server for file or directory listing accordingly
         if isdir then code, answer = %try_command(control, "nlst", file, {150, 125})
         else code, answer = %try_command(control, "retr", file, {150, 125}) end
-        if not code then 
-                control:close()
-                data:close()
-                return nil, answer 
-        end
+        data, answer = server:accept()
+        server:close()
+        if not data then return nil, answer end
         -- download whole file
         file, err = data:receive("*a")
         data:close()
@@ -314,19 +319,23 @@ end
 -- Stores a file
 -- Input
 --   control: control connection with server
---   data: data connection with server
+--   server: server socket bound to local address
 --   file: file name under current directory
 --   bytes: file contents in string 
 -- Returns
---   file: string with file contents, nil if error
+--   code: return code, nil if error
 --   answer: server answer or error message
 -----------------------------------------------------------------------------
-local store_file = function (control, data, file, bytes)
+local store_file = function (control, server, file, bytes)
+        local data
         local code, answer = %try_command(control, "stor", file, {150, 125})
         if not code then 
                 data:close()
                 return nil, answer 
         end
+        data, answer = server:accept()
+        server:close()
+        if not data then return nil, answer end
         -- send whole file and close connection to mark file end
         answer = data:send(bytes)
         data:close()
@@ -362,8 +371,8 @@ end
 --   err: error message if any
 -----------------------------------------------------------------------------
 function ftp_get(url, type)
-        local control, data, err
-        local answer, code, server, file, path
+        local control, server, data, err
+        local answer, code, server, pfile, file
         parsed = %split_url(url, {user = "anonymous", port = 21, pass = %EMAIL})
         -- start control connection
         control, err = connect(parsed.host, parsed.port)
@@ -376,21 +385,22 @@ function ftp_get(url, type)
         code, answer = %login(control, parsed.user, parsed.pass)
         if not code then return nil, answer end
         -- go to directory
-        file, path, isdir = %split_path(parsed.path)
-        code, answer = %cwd(control, path)
+        pfile = %split_path(parsed.path)
+        if not pfile then return nil, "invalid path" end
+        code, answer = %cwd(control, pfile.path)
         if not code then return nil, answer end
         -- change to binary type?
         code, answer = %change_type(control, type)
         if not code then return nil, answer end
-        -- start data connection
-        data, answer = %start_dataconnection(control)
-        if not data then return nil, answer end
+        -- setup passive connection
+        server, answer = %port(control)
+        if not server then return nil, answer end
         -- ask server to send file or directory listing
-        file, answer = %retrieve_file(control, data, file, isdir)
+        file, answer = %retrieve_file(control, server, pfile.name, pfile.isdir)
         if not file then return nil, answer end
         -- disconnect
         %logout(control)
-        -- return whatever file we received plus a possible error
+        -- return whatever file we received plus a possible error message
         return file, answer
 end
 
@@ -405,7 +415,7 @@ end
 -----------------------------------------------------------------------------
 function ftp_put(url, bytes, type)
         local control, data
-        local answer, code, server, file, path
+        local answer, code, server, file, pfile
         parsed = %split_url(url, {user = "anonymous", port = 21, pass = %EMAIL})
         -- start control connection
         control, answer = connect(parsed.host, parsed.port)
@@ -418,20 +428,21 @@ function ftp_put(url, bytes, type)
         code, answer = %login(control, parsed.user, parsed.pass)
         if not code then return answer end
         -- go to directory
-        file, path, isdir = %split_path(parsed.path)
-        code, answer = %cwd(control, path)
+        pfile = %split_path(parsed.path)
+        if not pfile or pfile.isdir then return "invalid path" end
+        code, answer = %cwd(control, pfile.path)
         if not code then return answer end
         -- change to binary type?
         code, answer = %change_type(control, type)
         if not code then return answer end
-        -- start data connection
-        data, answer = %start_dataconnection(control)
-        if not data then return answer end
-        -- ask server to send file or directory listing
-        code, answer = %store_file(control, data, file, bytes)
+        -- setup passive connection
+        server, answer = %port(control)
+        if not server then return answer end
+        -- ask server to send file
+        code, answer = %store_file(control, server, pfile.name, bytes)
         if not code then return answer end
         -- disconnect
         %logout(control)
-        -- return whatever file we received plus a possible error
+        -- no errors
         return nil
 end