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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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# Author: Matt Giuca, Tom Conway
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# Author: Matt Giuca, Tom Conway, Will Grant
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'''Python console RPC service.
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Provides an HTTP RPC interface to a Python console process.
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from common import (util, studpath)
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trampoline_path = os.path.join(conf.ivle_install_dir, "bin/trampoline")
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python_path = "/usr/bin/python" # Within jail
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console_dir = "/opt/ivle/console" # Within jail
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console_path = "/opt/ivle/console/python-console" # Within jail
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"""Handler for the Console Service AJAX backend application."""
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if len(req.path) > 0 and req.path[-1] == os.sep:
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# The path determines which "command" we are receiving
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if req.path == "start":
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elif req.path == "chat":
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req.throw_error(req.HTTP_BAD_REQUEST)
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def handle_start(req):
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jail_path = os.path.join(conf.jail_base, req.username)
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working_dir = os.path.join("/home", req.username) # Within jail
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# Get the UID of the logged-in user
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(_,_,uid,_,_,_,_) = pwd.getpwnam(req.username)
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# The user does not exist. This should have already failed the
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req.throw_error(req.HTTP_INTERNAL_SERVER_ERROR)
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# Set request attributes
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req.content_type = "text/plain"
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req.write_html_head_foot = False
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# TODO: Figure out the host name the console server is running on.
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# Find an available port on the server.
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# Start the console server (port, magic)
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# trampoline usage: tramp uid jail_dir working_dir script_path args
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# console usage: python-console port magic
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# TODO: Cleanup (don't use os.system)
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# TODO: Pass working_dir as argument, let console cd to it
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# Use "&" to run as a background process
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cmd = ' '.join([trampoline_path, str(uid), jail_path, console_dir,
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python_path, console_path, str(port), str(magic), "&"])
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#req.write(cmd + '\n')
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req.write(cjson.encode({"host": host, "port": port, "magic": magic}))
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req.throw_error(req.HTTP_NOT_IMPLEMENTED)
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from ivle.webapp.base.rest import JSONRESTView, named_operation
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from ivle.webapp.errors import BadRequest
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# XXX: Should be RPC view, with actions in URL?
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class ConsoleServiceRESTView(JSONRESTView):
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'''An RPC interface to a Python console.'''
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def get_permissions(self, user):
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@named_operation('use')
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def start(self, req, cwd=''):
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working_dir = os.path.join("/home", req.user.login, cwd)
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jail_path = os.path.join(req.config['paths']['jails']['mounts'],
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cons = ivle.console.Console(req.config, uid, jail_path, working_dir)
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# Assemble the key and return it. Yes, it is double-encoded.
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return {'key': cjson.encode({"host": cons.host,
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"magic": cons.magic}).encode('hex')}
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@named_operation('use')
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def chat(self, req, key, text='', kind="chat"):
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# The request *should* have the following four fields:
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# key: Hex JSON dict of host and port where the console server lives,
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# and the secret to use to digitally sign the communication with the
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# text: Fields to pass along to the console server
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# It simply acts as a proxy to the console server
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keydict = cjson.decode(key.decode('hex'))
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host = keydict['host']
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port = keydict['port']
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magic = keydict['magic']
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raise BadRequest("Invalid console key.")
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jail_path = os.path.join(req.config['paths']['jails']['mounts'],
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working_dir = os.path.join("/home", req.user.login) # Within jail
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# XXX: JSONRESTView should do this for us.
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text = text.decode('utf-8')
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msg = {'cmd':kind, 'text':text}
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json_response = ivle.chat.chat(host, port, msg, magic,decode=False)
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# Snoop the response from python-console to check that it's valid
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response = cjson.decode(json_response)
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except cjson.DecodeError:
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# Could not decode the reply from the python-console server
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response = {"terminate":
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"Communication to console process lost"}
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if "terminate" in response:
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response = restart_console(req.config, uid, jail_path,
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working_dir, response["terminate"])
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except socket.error, (enumber, estring):
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if enumber == errno.ECONNREFUSED:
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# Timeout: Restart the session
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response = restart_console(req.config, uid, jail_path,
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"The IVLE console has timed out due to inactivity")
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elif enumber == errno.ECONNRESET:
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# Communication issue: Restart the session
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response = restart_console(req.config, uid, jail_path,
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"Connection with the console has been reset")
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# Some other error - probably serious
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raise socket.error, (enumber, estring)
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def restart_console(config, uid, jail_path, working_dir, reason):
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"""Tells the client that it must be issued a new console since the old
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console is no longer availible. The client must accept the new key.
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Returns the JSON response to be given to the client.
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# Start a new console server console
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cons = ivle.console.Console(config, uid, jail_path, working_dir)
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# Make a JSON object to tell the browser to restart its console client
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new_key = cjson.encode(
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{"host": cons.host, "port": cons.port, "magic": cons.magic})
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return {"restart": reason, "key": new_key.encode("hex")}