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Patch #630829: Don't block on IAC, process suboptions.

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This commit is contained in:
Martin v. Löwis 2002-11-04 09:56:00 +00:00
parent a178cff979
commit 1da9c57c74
4 changed files with 93 additions and 32 deletions
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8
Doc/lib/libtelnetlib.tex
View File

@ -96,6 +96,14 @@ Return \code{''} if no cooked data available otherwise. This method
never blocks.
\end{methoddesc}
\begin{methoddesc}{read_sb_data}{}
Return the data collected between a SB/SE pair (suboption begin/end).
The callback should access these data when it was invoked with a
\code{SE} command. This method never blocks.
\versionadded{2.3}
\end{methoddesc}
\begin{methoddesc}{open}{host\optional{, port}}
Connect to a host.
The optional second argument is the port number, which

89
Lib/telnetlib.py
View File

@ -25,9 +25,6 @@ EOFError is needed in some cases to distinguish between "no data" and
"connection closed" (since the socket also appears ready for reading
when it is closed).
Bugs:
- may hang when connection is slow in the middle of an IAC sequence
To do:
- option negotiation
- timeout should be intrinsic to the connection object instead of an
@ -56,6 +53,8 @@ DO = chr(253)
WONT = chr(252)
WILL = chr(251)
theNULL = chr(0)
SB = chr(250)
SE = chr(240)
# Telnet protocol options code (don't change)
# These ones all come from arpa/telnet.h
@ -117,6 +116,7 @@ PRAGMA_LOGON = chr(138) # TELOPT PRAGMA LOGON
SSPI_LOGON = chr(139) # TELOPT SSPI LOGON
PRAGMA_HEARTBEAT = chr(140) # TELOPT PRAGMA HEARTBEAT
EXOPL = chr(255) # Extended-Options-List
NOOPT = chr(0)
class Telnet:
@ -161,10 +161,14 @@ class Telnet:
Reads all data in the cooked queue, without doing any socket
I/O.
read_sb_data()
Reads available data between SB ... SE sequence. Don't block.
set_option_negotiation_callback(callback)
Each time a telnet option is read on the input flow, this callback
(if set) is called with the following parameters :
callback(telnet socket, command (DO/DONT/WILL/WONT), option)
callback(telnet socket, command, option)
option will be chr(0) when there is no option.
No other action is done afterwards by telnetlib.
"""
@ -185,6 +189,9 @@ class Telnet:
self.irawq = 0
self.cookedq = ''
self.eof = 0
self.iacseq = '' # Buffer for IAC sequence.
self.sb = 0 # flag for SB and SE sequence.
self.sbdataq = ''
self.option_callback = None
if host is not None:
self.open(host, port)
@ -250,6 +257,8 @@ class Telnet:
self.sock.close()
self.sock = 0
self.eof = 1
self.iacseq = ''
self.sb = 0
def get_socket(self):
"""Return the socket object used internally."""
@ -380,6 +389,18 @@ class Telnet:
raise EOFError, 'telnet connection closed'
return buf
def read_sb_data(self):
"""Return any data available in the SB ... SE queue.
Return '' if no SB ... SE available. Should only be called
after seeing a SB or SE command. When a new SB command is
found, old unread SB data will be discarded. Don't block.
"""
buf = self.sbdataq
self.sbdataq = ''
return buf
def set_option_negotiation_callback(self, callback):
"""Provide a callback function called after each receipt of a telnet option."""
self.option_callback = callback
@ -391,40 +412,70 @@ class Telnet:
the midst of an IAC sequence.
"""
buf = ''
buf = ['', '']
try:
while self.rawq:
c = self.rawq_getchar()
if not self.iacseq:
if c == theNULL:
continue
if c == "\021":
continue
if c != IAC:
buf = buf + c
buf[self.sb] = buf[self.sb] + c
continue
c = self.rawq_getchar()
else:
self.iacseq += c
elif len(self.iacseq) == 1:
'IAC: IAC CMD [OPTION only for WILL/WONT/DO/DONT]'
if c in (DO, DONT, WILL, WONT):
self.iacseq += c
continue
self.iacseq = ''
if c == IAC:
buf = buf + c
elif c in (DO, DONT):
opt = self.rawq_getchar()
self.msg('IAC %s %d', c == DO and 'DO' or 'DONT', ord(opt))
buf[self.sb] = buf[self.sb] + c
else:
if c == SB: # SB ... SE start.
self.sb = 1
self.sbdataq = ''
elif c == SE:
self.sb = 0
self.sbdataq = self.sbdataq + buf[1]
buf[1] = ''
if self.option_callback:
self.option_callback(self.sock, c, opt)
# Callback is supposed to look into
# the sbdataq
self.option_callback(self.sock, c, NOOPT)
else:
# We can't offer automatic processing of
# suboptions. Alas, we should not get any
# unless we did a WILL/DO before.
self.msg('IAC %d not recognized' % ord(c))
elif len(self.iacseq) == 2:
cmd = self.iacseq[1]
self.iacseq = ''
opt = c
if cmd in (DO, DONT):
self.msg('IAC %s %d',
cmd == DO and 'DO' or 'DONT', ord(opt))
if self.option_callback:
self.option_callback(self.sock, cmd, opt)
else:
self.sock.sendall(IAC + WONT + opt)
elif c in (WILL, WONT):
opt = self.rawq_getchar()
elif cmd in (WILL, WONT):
self.msg('IAC %s %d',
c == WILL and 'WILL' or 'WONT', ord(opt))
cmd == WILL and 'WILL' or 'WONT', ord(opt))
if self.option_callback:
self.option_callback(self.sock, c, opt)
self.option_callback(self.sock, cmd, opt)
else:
self.sock.sendall(IAC + DONT + opt)
else:
self.msg('IAC %d not recognized' % ord(c))
except EOFError: # raised by self.rawq_getchar()
self.iacseq = '' # Reset on EOF
self.sb = 0
pass
self.cookedq = self.cookedq + buf
self.cookedq = self.cookedq + buf[0]
self.sbdataq = self.sbdataq + buf[1]
def rawq_getchar(self):
"""Get next char from raw queue.

1
Misc/ACKS
View File

@ -465,6 +465,7 @@ Steven Scott
Nick Seidenman
Fred Sells
Denis Severson
Ha Shao
Bruce Sherwood
Pete Shinners
Michael Shiplett

3
Misc/NEWS
View File

@ -1707,7 +1707,8 @@ Library
-------
- telnetlib includes symbolic names for the options, and support for
setting an option negotiation callback.
setting an option negotiation callback. It also supports processing
of suboptions.
- The new C standard no longer requires that math libraries set errno to
ERANGE on overflow. For platform libraries that exploit this new