#! /usr/bin/env python # -*- coding: ISO-8859-15 -*- # Tea4CUPS : Tee for CUPS # # (c) 2005 Jerome Alet # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 2 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. # # $Id$ # # import sys import os import popen2 import errno import md5 import cStringIO import shlex import tempfile import ConfigParser import select import signal import time from struct import unpack version = "2.00" class TeeError(Exception): """Base exception for Tea4CUPS related stuff.""" def __init__(self, message = ""): self.message = message Exception.__init__(self, message) def __repr__(self): return self.message __str__ = __repr__ class ConfigError(TeeError) : """Configuration related exceptions.""" pass class IPPError(TeeError) : """IPP related exceptions.""" pass class Popen4ForCUPS(popen2.Popen4) : """Our own class to execute real backends. Their first argument is different from their path so using native popen2.Popen3 would not be feasible. """ def __init__(self, cmd, bufsize=-1, arg0=None) : self.arg0 = arg0 popen2.Popen4.__init__(self, cmd, bufsize) def _run_child(self, cmd): try : MAXFD = os.sysconf("SC_OPEN_MAX") except (AttributeError, ValueError) : MAXFD = 256 for i in range(3, MAXFD) : try: os.close(i) except OSError: pass try: os.execvpe(cmd[0], [self.arg0 or cmd[0]] + cmd[1:], os.environ) finally: os._exit(1) # Some IPP constants OPERATION_ATTRIBUTES_TAG = 0x01 JOB_ATTRIBUTES_TAG = 0x02 END_OF_ATTRIBUTES_TAG = 0x03 PRINTER_ATTRIBUTES_TAG = 0x04 UNSUPPORTED_ATTRIBUTES_TAG = 0x05 class IPPMessage : """A class for IPP message files.""" def __init__(self, data) : """Initializes an IPP Message object.""" self.data = data self._attributes = {} self.curname = None self.tags = [ None ] * 256 # by default all tags reserved # Delimiter tags self.tags[0x01] = "operation-attributes-tag" self.tags[0x02] = "job-attributes-tag" self.tags[0x03] = "end-of-attributes-tag" self.tags[0x04] = "printer-attributes-tag" self.tags[0x05] = "unsupported-attributes-tag" # out of band values self.tags[0x10] = "unsupported" self.tags[0x11] = "reserved-for-future-default" self.tags[0x12] = "unknown" self.tags[0x13] = "no-value" # integer values self.tags[0x20] = "generic-integer" self.tags[0x21] = "integer" self.tags[0x22] = "boolean" self.tags[0x23] = "enum" # octetString self.tags[0x30] = "octetString-with-an-unspecified-format" self.tags[0x31] = "dateTime" self.tags[0x32] = "resolution" self.tags[0x33] = "rangeOfInteger" self.tags[0x34] = "reserved-for-collection" self.tags[0x35] = "textWithLanguage" self.tags[0x36] = "nameWithLanguage" # character strings self.tags[0x20] = "generic-character-string" self.tags[0x41] = "textWithoutLanguage" self.tags[0x42] = "nameWithoutLanguage" # self.tags[0x43] = "reserved" self.tags[0x44] = "keyword" self.tags[0x45] = "uri" self.tags[0x46] = "uriScheme" self.tags[0x47] = "charset" self.tags[0x48] = "naturalLanguage" self.tags[0x49] = "mimeMediaType" # now parses the IPP message self.parse() def __getattr__(self, attrname) : """Allows self.attributes to return the attributes names.""" if attrname == "attributes" : keys = self._attributes.keys() keys.sort() return keys raise AttributeError, attrname def __getitem__(self, ippattrname) : """Fakes a dictionnary d['key'] notation.""" value = self._attributes.get(ippattrname) if value is not None : if len(value) == 1 : value = value[0] return value get = __getitem__ def parseTag(self) : """Extracts information from an IPP tag.""" pos = self.position valuetag = self.tags[ord(self.data[pos])] # print valuetag.get("name") pos += 1 posend = pos2 = pos + 2 namelength = unpack(">H", self.data[pos:pos2])[0] if not namelength : name = self.curname else : posend += namelength self.curname = name = self.data[pos2:posend] pos2 = posend + 2 valuelength = unpack(">H", self.data[posend:pos2])[0] posend = pos2 + valuelength value = self.data[pos2:posend] oldval = self._attributes.setdefault(name, []) oldval.append(value) return posend - self.position def operation_attributes_tag(self) : """Indicates that the parser enters into an operation-attributes-tag group.""" return self.parseTag() def job_attributes_tag(self) : """Indicates that the parser enters into an operation-attributes-tag group.""" return self.parseTag() def printer_attributes_tag(self) : """Indicates that the parser enters into an operation-attributes-tag group.""" return self.parseTag() def parse(self) : """Parses an IPP Message. NB : Only a subset of RFC2910 is implemented. We are only interested in textual informations for now anyway. """ self.version = "%s.%s" % (ord(self.data[0]), ord(self.data[1])) self.operation_id = "0x%04x" % unpack(">H", self.data[2:4])[0] self.request_id = "0x%08x" % unpack(">I", self.data[4:8])[0] self.position = 8 try : tag = ord(self.data[self.position]) while tag != END_OF_ATTRIBUTES_TAG : self.position += 1 name = self.tags[tag] if name is not None : func = getattr(self, name.replace("-", "_"), None) if func is not None : self.position += func() if ord(self.data[self.position]) > UNSUPPORTED_ATTRIBUTES_TAG : self.position -= 1 continue tag = ord(self.data[self.position]) except IndexError : raise IPPError, "Unexpected end of IPP message." class FakeConfig : """Fakes a configuration file parser.""" def get(self, section, option, raw=0) : """Fakes the retrieval of a global option.""" raise ConfigError, "Invalid configuration file : no option %s in section [%s]" % (option, section) class CupsBackend : """Base class for tools with no database access.""" def __init__(self) : """Initializes the CUPS backend wrapper.""" signal.signal(signal.SIGTERM, signal.SIG_IGN) signal.signal(signal.SIGPIPE, signal.SIG_IGN) self.MyName = "Tea4CUPS" self.myname = "tea4cups" self.pid = os.getpid() confdir = os.environ.get("CUPS_SERVERROOT", ".") self.conffile = os.path.join(confdir, "%s.conf" % self.myname) if os.path.isfile(self.conffile) : self.config = ConfigParser.ConfigParser() self.config.read([self.conffile]) self.debug = self.isTrue(self.getGlobalOption("debug", ignore=1)) else : self.config = FakeConfig() self.debug = 1 # no config, so force debug mode ! def logInfo(self, message, level="info") : """Logs a message to CUPS' error_log file.""" sys.stderr.write("%s: %s v%s (PID %i) : %s\n" % (level.upper(), self.MyName, version, os.getpid(), message)) sys.stderr.flush() def logDebug(self, message) : """Logs something to debug output if debug is enabled.""" if self.debug : self.logInfo(message, level="debug") def isTrue(self, option) : """Returns 1 if option is set to true, else 0.""" if (option is not None) and (option.upper().strip() in ['Y', 'YES', '1', 'ON', 'T', 'TRUE']) : return 1 else : return 0 def getGlobalOption(self, option, ignore=0) : """Returns an option from the global section, or raises a ConfigError if ignore is not set, else returns None.""" try : return self.config.get("global", option, raw=1) except (ConfigParser.NoSectionError, ConfigParser.NoOptionError) : if not ignore : raise ConfigError, "Option %s not found in section global of %s" % (option, self.conffile) def getPrintQueueOption(self, printqueuename, option, ignore=0) : """Returns an option from the printer section, or the global section, or raises a ConfigError.""" globaloption = self.getGlobalOption(option, ignore=1) try : return self.config.get(printqueuename, option, raw=1) except (ConfigParser.NoSectionError, ConfigParser.NoOptionError) : if globaloption is not None : return globaloption elif not ignore : raise ConfigError, "Option %s not found in section [%s] of %s" % (option, printqueuename, self.conffile) def enumBranches(self, printqueuename, branchtype="tee") : """Returns the list of branchtypes branches for a particular section's.""" branchbasename = "%s_" % branchtype.lower() try : globalbranches = [ (k, v) for (k, v) in self.config.items("global") if k.startswith(branchbasename) ] except ConfigParser.NoSectionError, msg : raise ConfigError, "Invalid configuration file : %s" % msg try : sectionbranches = [ (k, v) for (k, v) in self.config.items(printqueuename) if k.startswith(branchbasename) ] except ConfigParser.NoSectionError, msg : self.logInfo("No section for print queue %s : %s" % (printqueuename, msg)) sectionbranches = [] branches = {} for (k, v) in globalbranches : value = v.strip() if value : branches[k] = value for (k, v) in sectionbranches : value = v.strip() if value : branches[k] = value # overwrite any global option or set a new value else : del branches[k] # empty value disables a global option return branches def discoverOtherBackends(self) : """Discovers the other CUPS backends. Executes each existing backend in turn in device enumeration mode. Returns the list of available backends. """ # Unfortunately this method can't output any debug information # to stdout or stderr, else CUPS considers that the device is # not available. available = [] (directory, myname) = os.path.split(sys.argv[0]) if not directory : directory = "./" tmpdir = tempfile.gettempdir() lockfilename = os.path.join(tmpdir, "%s..LCK" % myname) if os.path.exists(lockfilename) : lockfile = open(lockfilename, "r") pid = int(lockfile.read()) lockfile.close() try : # see if the pid contained in the lock file is still running os.kill(pid, 0) except OSError, e : if e.errno != errno.EPERM : # process doesn't exist anymore os.remove(lockfilename) if not os.path.exists(lockfilename) : lockfile = open(lockfilename, "w") lockfile.write("%i" % self.pid) lockfile.close() allbackends = [ os.path.join(directory, b) \ for b in os.listdir(directory) if os.access(os.path.join(directory, b), os.X_OK) \ and (b != myname)] for backend in allbackends : answer = os.popen(backend, "r") try : devices = [line.strip() for line in answer.readlines()] except : devices = [] status = answer.close() if status is None : for d in devices : # each line is of the form : # 'xxxx xxxx "xxxx xxx" "xxxx xxx"' # so we have to decompose it carefully fdevice = cStringIO.StringIO(d) tokenizer = shlex.shlex(fdevice) tokenizer.wordchars = tokenizer.wordchars + \ r".:,?!~/\_$*-+={}[]()#" arguments = [] while 1 : token = tokenizer.get_token() if token : arguments.append(token) else : break fdevice.close() try : (devicetype, device, name, fullname) = arguments except ValueError : pass # ignore this 'bizarre' device else : if name.startswith('"') and name.endswith('"') : name = name[1:-1] if fullname.startswith('"') and fullname.endswith('"') : fullname = fullname[1:-1] available.append('%s %s:%s "%s+%s" "%s managed %s"' \ % (devicetype, self.myname, device, self.MyName, name, self.MyName, fullname)) os.remove(lockfilename) available.append('direct %s:// "%s+Nothing" "%s managed Virtual Printer"' \ % (self.myname, self.MyName, self.MyName)) return available def initBackend(self) : """Initializes the backend's attributes.""" # check that the DEVICE_URI environment variable's value is # prefixed with self.myname otherwise don't touch it. # If this is the case, we have to remove the prefix from # the environment before launching the real backend muststartwith = "%s:" % self.myname device_uri = os.environ.get("DEVICE_URI", "") if device_uri.startswith(muststartwith) : fulldevice_uri = device_uri[:] device_uri = fulldevice_uri[len(muststartwith):] for i in range(2) : if device_uri.startswith("/") : device_uri = device_uri[1:] try : (backend, destination) = device_uri.split(":", 1) except ValueError : if not device_uri : self.logDebug("Not attached to an existing print queue.") backend = "" else : raise TeeError, "Invalid DEVICE_URI : %s\n" % device_uri self.JobId = sys.argv[1].strip() self.UserName = sys.argv[2].strip() self.Title = sys.argv[3].strip() self.Copies = int(sys.argv[4].strip()) self.Options = sys.argv[5].strip() if len(sys.argv) == 7 : self.InputFile = sys.argv[6] # read job's datas from file else : self.InputFile = None # read job's datas from stdin self.RealBackend = backend self.DeviceURI = device_uri self.PrinterName = os.environ.get("PRINTER", "") self.Directory = self.getPrintQueueOption(self.PrinterName, "directory") self.DataFile = os.path.join(self.Directory, "%s-%s-%s-%s" % (self.myname, self.PrinterName, self.UserName, self.JobId)) self.ClientHost = self.extractJobOriginatingHostName() def getCupsConfigDirectives(self, directives=[]) : """Retrieves some CUPS directives from its configuration file. Returns a mapping with lowercased directives as keys and their setting as values. """ dirvalues = {} cupsroot = os.environ.get("CUPS_SERVERROOT", "/etc/cups") cupsdconf = os.path.join(cupsroot, "cupsd.conf") try : conffile = open(cupsdconf, "r") except IOError : raise TeeError, "Unable to open %s" % cupsdconf else : for line in conffile.readlines() : linecopy = line.strip().lower() for di in [d.lower() for d in directives] : if linecopy.startswith("%s " % di) : try : val = line.split()[1] except : pass # ignore errors, we take the last value in any case. else : dirvalues[di] = val conffile.close() return dirvalues def extractJobOriginatingHostName(self) : """Extracts the client's hostname or IP address from the CUPS message file for current job.""" cupsdconf = self.getCupsConfigDirectives(["RequestRoot"]) requestroot = cupsdconf.get("requestroot", "/var/spool/cups") if (len(self.JobId) < 5) and self.JobId.isdigit() : ippmessagefile = "c%05i" % int(self.JobId) else : ippmessagefile = "c%s" % self.JobId ippmessagefile = os.path.join(requestroot, ippmessagefile) ippmessage = {} try : ippdatafile = open(ippmessagefile) except : self.logInfo("Unable to open IPP message file %s" % ippmessagefile, "warn") else : self.logDebug("Parsing of IPP message file %s begins." % ippmessagefile) try : ippmessage = IPPMessage(ippdatafile.read()) except IPPError, msg : self.logInfo("Error while parsing %s : %s" % (ippmessagefile, msg), "warn") else : self.logDebug("Parsing of IPP message file %s ends." % ippmessagefile) ippdatafile.close() return ippmessage.get("job-originating-host-name") def exportAttributes(self) : """Exports our backend's attributes to the environment.""" os.environ["DEVICE_URI"] = self.DeviceURI # WARNING ! os.environ["TEAPRINTERNAME"] = self.PrinterName os.environ["TEADIRECTORY"] = self.Directory os.environ["TEADATAFILE"] = self.DataFile os.environ["TEAJOBSIZE"] = str(self.JobSize) os.environ["TEAMD5SUM"] = self.JobMD5Sum os.environ["TEACLIENTHOST"] = self.ClientHost or "" os.environ["TEAJOBID"] = self.JobId os.environ["TEAUSERNAME"] = self.UserName os.environ["TEATITLE"] = self.Title os.environ["TEACOPIES"] = str(self.Copies) os.environ["TEAOPTIONS"] = self.Options os.environ["TEAINPUTFILE"] = self.InputFile or "" def saveDatasAndCheckSum(self) : """Saves the input datas into a static file.""" self.logDebug("Duplicating data stream into %s" % self.DataFile) mustclose = 0 if self.InputFile is not None : infile = open(self.InputFile, "rb") mustclose = 1 else : infile = sys.stdin CHUNK = 64*1024 # read 64 Kb at a time dummy = 0 sizeread = 0 checksum = md5.new() outfile = open(self.DataFile, "wb") while 1 : data = infile.read(CHUNK) if not data : break sizeread += len(data) outfile.write(data) checksum.update(data) if not (dummy % 32) : # Only display every 2 Mb self.logDebug("%s bytes saved..." % sizeread) dummy += 1 outfile.close() if mustclose : infile.close() self.JobSize = sizeread self.JobMD5Sum = checksum.hexdigest() self.logDebug("Job %s is %s bytes long." % (self.JobId, self.JobSize)) self.logDebug("Job %s MD5 sum is %s" % (self.JobId, self.JobMD5Sum)) def cleanUp(self) : """Cleans up the place.""" if not self.isTrue(self.getPrintQueueOption(self.PrinterName, "keepfiles", ignore=1)) : os.remove(self.DataFile) def sigtermHandler(self, signum, frame) : """Sets an attribute whenever SIGTERM is received.""" self.gotSigTerm = 1 self.logInfo("SIGTERM received for Job %s." % self.JobId) def runBranches(self) : """Launches each hook or tee defined for the current print queue.""" exitcode = 0 self.isCancelled = 0 # did a prehook cancel the print job ? self.gotSigTerm = 0 signal.signal(signal.SIGTERM, self.sigtermHandler) serialize = self.isTrue(self.getPrintQueueOption(self.PrinterName, "serialize", ignore=1)) for branchtype in ["prehook", "tee", "posthook"] : branches = self.enumBranches(self.PrinterName, branchtype) status = self.runCommands(branchtype, branches, serialize) if status : exitcode = status if (branchtype == "prehook") and self.isCancelled : break # We don't want to execute tees or posthooks in this case signal.signal(signal.SIGTERM, signal.SIG_IGN) if not exitcode : self.logInfo("OK") else : self.logInfo("An error occured, please check CUPS' error_log file.") return exitcode def runCommands(self, btype, branches, serialize) : """Runs the commands for a particular branch type.""" exitcode = 0 btype = btype.lower() btypetitle = btype.title() branchlist = branches.keys() branchlist.sort() if serialize : self.logDebug("Begin serialized %ss" % btypetitle) if (btype == "tee") and self.RealBackend : self.logDebug("Launching original backend %s for printer %s" % (self.RealBackend, self.PrinterName)) retcode = self.runOriginalBackend() if os.WIFEXITED(retcode) : retcode = os.WEXITSTATUS(retcode) os.environ["TEASTATUS"] = str(retcode) exitcode = retcode for branch in branchlist : command = branches[branch] if self.gotSigTerm : break self.logDebug("Launching %s : %s" % (branch, command)) retcode = os.system(command) self.logDebug("Exit code for %s %s on printer %s is %s" % (btype, branch, self.PrinterName, retcode)) if os.WIFEXITED(retcode) : retcode = os.WEXITSTATUS(retcode) if retcode : if (btype == "prehook") and (retcode == 255) : # -1 self.logInfo("Job %s cancelled by prehook %s" % (self.JobId, branch)) self.isCancelled = 1 else : self.logInfo("%s %s on printer %s didn't exit successfully." % (btypetitle, branch, self.PrinterName), "error") exitcode = 1 self.logDebug("End serialized %ss" % btypetitle) else : self.logDebug("Begin forked %ss" % btypetitle) pids = {} if (btype == "tee") and self.RealBackend : branches["Original backend"] = None # Fakes a tee to launch one more child branchlist = ["Original backend"] + branchlist for branch in branchlist : command = branches[branch] if self.gotSigTerm : break pid = os.fork() if pid : pids[branch] = pid else : if branch == "Original backend" : self.logDebug("Launching original backend %s for printer %s" % (self.RealBackend, self.PrinterName)) sys.exit(self.runOriginalBackend()) else : self.logDebug("Launching %s : %s" % (branch, command)) retcode = os.system(command) if os.WIFEXITED(retcode) : retcode = os.WEXITSTATUS(retcode) else : retcode = -1 sys.exit(retcode) for (branch, pid) in pids.items() : (childpid, retcode) = os.waitpid(pid, 0) self.logDebug("Exit code for %s %s (PID %s) on printer %s is %s" % (btype, branch, childpid, self.PrinterName, retcode)) if os.WIFEXITED(retcode) : retcode = os.WEXITSTATUS(retcode) if retcode : if (btype == "prehook") and (retcode == 255) : # -1 self.logInfo("Job %s cancelled by prehook %s" % (self.JobId, branch)) self.isCancelled = 1 else : self.logInfo("%s %s (PID %s) on printer %s didn't exit successfully." % (btypetitle, branch, childpid, self.PrinterName), "error") exitcode = 1 if branch == "Original backend" : os.environ["TEASTATUS"] = str(retcode) self.logDebug("End forked %ss" % btypetitle) return exitcode def unregisterFileNo(self, pollobj, fileno) : """Removes a file handle from the polling object.""" try : pollobj.unregister(fileno) except KeyError : self.logInfo("File number %s unregistered twice from polling object, ignored." % fileno, "warn") except : self.logDebug("Error while unregistering file number %s from polling object." % fileno) else : self.logDebug("File number %s unregistered from polling object." % fileno) def formatFileEvent(self, fd, mask) : """Formats file debug info.""" maskval = [] if mask & select.POLLIN : maskval.append("POLLIN") if mask & select.POLLOUT : maskval.append("POLLOUT") if mask & select.POLLPRI : maskval.append("POLLPRI") if mask & select.POLLERR : maskval.append("POLLERR") if mask & select.POLLHUP : maskval.append("POLLHUP") if mask & select.POLLNVAL : maskval.append("POLLNVAL") return "%s (%s)" % (fd, " | ".join(maskval)) def runOriginalBackend(self) : """Launches the original backend.""" originalbackend = os.path.join(os.path.split(sys.argv[0])[0], self.RealBackend) arguments = sys.argv self.logDebug("Starting original backend %s with args %s" % (originalbackend, " ".join(['"%s"' % a for a in ([os.environ["DEVICE_URI"]] + arguments[1:])]))) subprocess = Popen4ForCUPS([originalbackend] + arguments[1:], bufsize=0, arg0=os.environ["DEVICE_URI"]) # Save file descriptors, we will need them later. stderrfno = sys.stderr.fileno() fromcfno = subprocess.fromchild.fileno() tocfno = subprocess.tochild.fileno() # We will have to be careful when dealing with I/O # So we use a poll object to know when to read or write pollster = select.poll() pollster.register(fromcfno, select.POLLIN | select.POLLPRI) pollster.register(stderrfno, select.POLLOUT) pollster.register(tocfno, select.POLLOUT) # Initialize our buffers indata = "" outdata = "" endinput = endoutput = 0 inputclosed = outputclosed = 0 totaltochild = totalfromcups = 0 totalfromchild = totaltocups = 0 if self.InputFile is None : # this is not a real file, we read the job's data # from our temporary file which is a copy of stdin inf = open(self.DataFile, "rb") infno = inf.fileno() pollster.register(infno, select.POLLIN | select.POLLPRI) else : # job's data is in a file, no need to pass the data # to the original backend self.logDebug("Job's data is in %s" % self.InputFile) infno = None endinput = 1 self.logDebug("Entering streams polling loop...") MEGABYTE = 1024*1024 killed = 0 status = -1 while (status == -1) and (not killed) and not (inputclosed and outputclosed) : # First check if original backend is still alive status = subprocess.poll() # Now if we got SIGTERM, we have # to kill -TERM the original backend if self.gotSigTerm and not killed : try : os.kill(subprocess.pid, signal.SIGTERM) except OSError, msg : # ignore but logs if process was already killed. self.logDebug("Error while sending signal to pid %s : %s" % (subprocess.pid, msg)) else : self.logInfo(_("SIGTERM was sent to original backend %s (PID %s)") % (originalbackend, subprocess.pid)) killed = 1 # In any case, deal with any remaining I/O try : availablefds = pollster.poll(5000) except select.error, msg : self.logDebug("Interrupted poll : %s" % msg) availablefds = [] if not availablefds : self.logDebug("Nothing to do, sleeping a bit...") time.sleep(0.01) # give some time to the system else : for (fd, mask) in availablefds : try : if mask & select.POLLOUT : # We can write if fd == tocfno : if indata : try : nbwritten = os.write(fd, indata) except (OSError, IOError), msg : self.logDebug("Error while writing to original backend's stdin %s : %s" % (fd, msg)) else : if len(indata) != nbwritten : self.logDebug("Short write to original backend's input !") totaltochild += nbwritten self.logDebug("%s bytes sent to original backend so far..." % totaltochild) indata = indata[nbwritten:] else : self.logDebug("No data to send to original backend yet, sleeping a bit...") time.sleep(0.01) if endinput : self.unregisterFileNo(pollster, tocfno) self.logDebug("Closing original backend's stdin.") os.close(tocfno) inputclosed = 1 elif fd == stderrfno : if outdata : try : nbwritten = os.write(fd, outdata) except (OSError, IOError), msg : self.logDebug("Error while writing to CUPS back channel (stderr) %s : %s" % (fd, msg)) else : if len(outdata) != nbwritten : self.logDebug("Short write to stderr (CUPS) !") totaltocups += nbwritten self.logDebug("%s bytes sent back to CUPS so far..." % totaltocups) outdata = outdata[nbwritten:] else : # self.logDebug("No data to send back to CUPS yet, sleeping a bit...") # Uncommenting this fills your logs time.sleep(0.01) # Give some time to the system, stderr is ALWAYS writeable it seems. if endoutput : self.unregisterFileNo(pollster, stderrfno) outputclosed = 1 else : self.logDebug("Unexpected : %s - Sleeping a bit..." % self.formatFileEvent(fd, mask)) time.sleep(0.01) if mask & (select.POLLIN | select.POLLPRI) : # We have something to read try : data = os.read(fd, MEGABYTE) except (IOError, OSError), msg : self.logDebug("Error while reading file %s : %s" % (fd, msg)) else : if fd == infno : if not data : # If yes, then no more input data self.unregisterFileNo(pollster, infno) self.logDebug("Input data ends.") endinput = 1 # this happens with real files. else : indata += data totalfromcups += len(data) self.logDebug("%s bytes read from CUPS so far..." % totalfromcups) elif fd == fromcfno : if not data : self.logDebug("No back channel data to read from original backend yet, sleeping a bit...") time.sleep(0.01) else : outdata += data totalfromchild += len(data) self.logDebug("%s bytes read from original backend so far..." % totalfromchild) else : self.logDebug("Unexpected : %s - Sleeping a bit..." % self.formatFileEvent(fd, mask)) time.sleep(0.01) if mask & (select.POLLHUP | select.POLLERR) : # Treat POLLERR as an EOF. # Some standard I/O stream has no more datas self.unregisterFileNo(pollster, fd) if fd == infno : # Here we are in the case where the input file is stdin. # which has no more data to be read. self.logDebug("Input data ends.") endinput = 1 elif fd == fromcfno : # We are no more interested in this file descriptor self.logDebug("Closing original backend's stdout+stderr.") os.close(fromcfno) endoutput = 1 else : self.logDebug("Unexpected : %s - Sleeping a bit..." % self.formatFileEvent(fd, mask)) time.sleep(0.01) if mask & select.POLLNVAL : self.logDebug("File %s was closed. Unregistering from polling object." % fd) self.unregisterFileNo(pollster, fd) except IOError, msg : self.logDebug("Got an IOError : %s" % msg) # we got signalled during an I/O # We must close the original backend's input stream if killed and not inputclosed : self.logDebug("Forcing close of original backend's stdin.") os.close(tocfno) self.logDebug("Exiting streams polling loop...") self.logDebug("input data's final length : %s" % len(indata)) self.logDebug("back-channel data's final length : %s" % len(outdata)) self.logDebug("Total bytes read from CUPS (job's datas) : %s" % totalfromcups) self.logDebug("Total bytes sent to original backend (job's datas) : %s" % totaltochild) self.logDebug("Total bytes read from original backend (back-channel datas) : %s" % totalfromchild) self.logDebug("Total bytes sent back to CUPS (back-channel datas) : %s" % totaltocups) # Check exit code of original CUPS backend. if status == -1 : # we exited the loop before the original backend exited # now we have to wait for it to finish and get its status self.logDebug("Waiting for original backend to exit...") try : status = subprocess.wait() except OSError : # already dead : TODO : detect when abnormal status = 0 if os.WIFEXITED(status) : return os.WEXITSTATUS(status) elif not killed : self.logInfo("CUPS backend %s died abnormally." % originalbackend, "error") return -1 else : return 1 if __name__ == "__main__" : # This is a CUPS backend, we should act and die like a CUPS backend wrapper = CupsBackend() if len(sys.argv) == 1 : print "\n".join(wrapper.discoverOtherBackends()) sys.exit(0) elif len(sys.argv) not in (6, 7) : sys.stderr.write("ERROR: %s job-id user title copies options [file]\n"\ % sys.argv[0]) sys.exit(1) else : try : wrapper.initBackend() wrapper.saveDatasAndCheckSum() wrapper.exportAttributes() retcode = wrapper.runBranches() wrapper.cleanUp() except SystemExit, e : retcode = e.code except : import traceback lines = [] for line in traceback.format_exception(*sys.exc_info()) : lines.extend([l for l in line.split("\n") if l]) msg = "ERROR: ".join(["%s (PID %s) : %s\n" % (wrapper.MyName, wrapper.pid, l) for l in (["ERROR: Tea4CUPS v%s" % version] + lines)]) sys.stderr.write(msg) sys.stderr.flush() retcode = 1 sys.exit(retcode)