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|
require 'ffi'
module PTY
private
module LibC
extend FFI::Library
# forkpty(3) is in libutil on linux, libc on MacOS/BSD
if FFI::Platform.linux?
ffi_lib 'libutil'
else
ffi_lib FFI::Library::LIBC
end
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
attach_function :dup, [ :int ], :int
end
Buffer = FFI::Buffer
def self.build_args(args)
cmd = args.shift
cmd_args = args.map do |arg|
FFI::MemoryPointer.from_string(arg)
end
exec_args = FFI::MemoryPointer.new(:pointer, 1 + cmd_args.length + 1)
exec_cmd = FFI::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)
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)
rfp = FFI::IO.for_fd(masterfd, "r")
wfp = FFI::IO.for_fd(LibC.dup(masterfd), "w")
if block_given?
yield rfp, wfp, pid
rfp.close unless rfp.closed?
wfp.close unless wfp.closed?
else
[ rfp, wfp, pid ]
end
end
def self.spawn(*args, &block)
self.getpty("/bin/sh", "-c", args[0], &block)
end
end
module LibC
extend FFI::Library
ffi_lib FFI::Library::LIBC
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|
#PTY.spawn("ls -laR /") { |rfd, wfd, pid|
puts "child pid=#{pid}"
while !rfd.eof? && (buf = rfd.gets)
puts "child: '#{buf.strip}'"
end
}
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