Add a PTY module sample. Its not exactly a full implementation yet.

git-svn-id: http://svn.codehaus.org/jruby/trunk/jruby@7604 961051c9-f516-0410-bf72-c9f7e237a7b7

lib/ruby/site_ruby/1.8/ffi/ffi.rb

@@ -181,6 +181,9 @@ def self.find_type(name)
     4 => :int,
     8 => :long_long,
   }
+  def self.type_size(t)
+    JRuby::FFI.type_size(t)
+  end
 end
 
 module JRuby::FFI
@@ -289,6 +292,7 @@ class Config
     NativeType::FLOAT64 => 8,
     NativeType::LONG => JRuby::FFI::Platform::LONG_SIZE / 8,
     NativeType::ULONG => JRuby::FFI::Platform::LONG_SIZE / 8,
+    NativeType::POINTER => JRuby::FFI::Platform::ADDRESS_SIZE / 8,
   }
 
   def self.size_to_type(size)

lib/ruby/site_ruby/1.8/ffi/memorypointer.rb

@@ -40,6 +40,11 @@ def self.new(type, count=nil, clear=true)
           ptr
         end
       end
+      def self.from_string(s)
+        ptr = self.new(s.length + 1, 1, false)
+        ptr.put_string(0, s)
+        ptr
+      end
       # Indicates how many bytes the type that the pointer is cast as uses.
       attr_accessor :type_size
 

samples/ffi/pty.rb

@@ -0,0 +1,109 @@
+require 'ffi'
+
+
+module PTY
+  private
+  module LibC
+    extend JRuby::FFI::Library
+    attach_function :forkpty, [ :buffer_out, :buffer_out, :buffer_in, :buffer_in ], :pid_t
+    attach_function :openpty, [ :buffer_out, :buffer_out, :buffer_out, :buffer_in, :buffer_in ], :int
+    attach_function :login_tty, [ :int ], :int
+    attach_function :close, [ :int ], :int
+    attach_function :strerror, [ :int ], :string
+    attach_function :fork, [], :pid_t
+    attach_function :execv, [ :string, :buffer_in ], :int
+    attach_function :execvp, [ :string, :buffer_in ], :int
+    attach_function :dup2, [ :int, :int ], :int
+  end
+  Buffer = JRuby::FFI::Buffer
+  def self.build_args(args)
+    cmd = args.shift
+    cmd_args = args.map do |arg|
+      MemoryPointer.from_string(arg)
+    end
+    exec_args = MemoryPointer.new(:pointer, 1 + cmd_args.length + 1)
+    exec_cmd = MemoryPointer.from_string(cmd)
+    exec_args[0].put_pointer(0, exec_cmd)
+    cmd_args.each_with_index do |arg, i|
+      exec_args[i + 1].put_pointer(0, arg)
+    end
+    [ cmd, exec_args ]
+  end
+  public
+  def self.getpty(*args, &block)
+    mfdp = Buffer.new :int
+    name = Buffer.new 1024
+    #
+    # All the execv setup is done in the parent, since doing anything other than
+    # execv in the child after fork is really flakey
+    #
+    exec_cmd, exec_args = build_args(args)
+    pid = LibC.forkpty(mfdp, name, nil, nil)
+    raise "forkpty failed: #{LibC.strerror(FFI.errno)}" if pid < 0    
+    if pid == 0
+      LibC.execvp(exec_cmd, exec_args)
+      exit 1
+    end
+    masterfd = mfdp.get_int(0)
+    if block_given?
+      yield masterfd, masterfd, pid
+      LibC.close(masterfd)
+    else
+      [ masterfd, masterfd, pid ]
+    end
+  end
+  def self.getpty2(*args, &block)
+    mfdp = Buffer.alloc_out :int
+    sfdp = Buffer.alloc_out :int
+    name = Buffer.alloc_out 1024
+    #
+    # All the execv setup is done in the parent, since doing anything other than
+    # execv in the child after fork is really flakey
+    #
+    exec_cmd, exec_args = build_args(args)
+    retval = LibC.openpty(mfdp, sfdp, name, nil, nil)
+    raise "openpty failed: #{LibC.strerror(FFI.errno)}" unless retval == 0
+    pid = LibC.fork()
+    if pid < 0
+      error = FFI.errno
+      LibC.close(mfdp.get_int(0))
+      LibC.close(sfdp.get_int(0))
+      raise "fork failed: #{LibC.strerror(error)}"
+    end
+    if pid == 0
+      LibC.close(mfdp.get_int(0))
+      # Make the slave fd the new stdin/out/err
+      fd = sfdp.get_int(0)
+      LibC.dup2(fd, 0)
+      LibC.dup2(fd, 1)
+      LibC.dup2(fd, 2)
+      LibC.close(fd)
+      LibC.login_tty(0)
+      LibC.execvp(exec_cmd, exec_args)
+      exit 1
+    end
+    slavefd = sfdp.get_int(0)
+    LibC.close(slavefd) # not needed in the parent
+    masterfd = mfdp.get_int(0)
+    if block_given?
+      yield masterfd, masterfd, pid
+      LibC.close(masterfd)
+    else
+      [ masterfd, masterfd, pid ]
+    end
+  end
+
+
+end
+module LibC
+  extend JRuby::FFI::Library
+  attach_function :close, [ :int ], :int
+  attach_function :write, [ :int, :buffer_in, :size_t ], :ssize_t
+  attach_function :read, [ :int, :buffer_out, :size_t ], :ssize_t
+end
+PTY.getpty("/bin/ls", "-alR", "/") { |rfd, wfd, pid|
+  puts "child pid=#{pid}"
+  while LibC.read(rfd, buf = 0.chr * 256, 256) > 0
+    puts "Received from child='#{buf.strip}'"
+  end
+}