- read: improve error handling -> raise exception when device fails (e.g. unplugged USB serial convertors)

- write: raise SerialExceptions, not other exceptions from the system

1 files changed, 9 insertions, 4 deletions

diff --git a/pyserial/serial/serialposix.py b/pyserial/serial/serialposix.py
index 20f6347..53b6040 100644
--- a/pyserial/serial/serialposix.py
+++ b/pyserial/serial/serialposix.py
@@ -445,13 +445,18 @@ class PosixSerial(SerialBase):
            until the requested number of bytes is read."""
         if self.fd is None: raise portNotOpenError
         read = bytearray()
+        poll = select.poll()
+        poll.register(self.fd, select.POLLIN|select.POLLERR|select.POLLHUP|select.POLLNVAL)
         inp = None
         if size > 0:
             while len(read) < size:
                 # print "\tread(): size",size, "have", len(read)    #debug
-                ready,_,_ = select.select([self.fd], [], [], self._timeout)
-                if not ready:
-                    break   # timeout
+                # wait until device becomes ready to read (or something fails)
+                for fd, event in poll.poll(self._timeout):
+                    if event & (select.POLLERR|select.POLLHUP|select.POLLNVAL):
+                        raise SerialException('device reports error (poll)')
+                    #  we don't care if it is select.POLLIN or timeout, that's
+                    #  handled below
                 buf = os.read(self.fd, size - len(read))
                 read.extend(buf)
                 if ((self._timeout is not None and self._timeout >= 0) or 
@@ -484,7 +489,7 @@ class PosixSerial(SerialBase):
                 t = t - n
             except OSError, v:
                 if v.errno != errno.EAGAIN:
-                    raise
+                    raise SerialException('write failed: %s' % (v,))
         return len(data)
 
     def flush(self):