def process(self):
assert not self.closed
assert self.queue
conn = self.queue[0]
if len(self.queue) > 1:
self.log('queued request, qlen=%s' % len(self.queue))
# Try to read the single byte written by the child.
# This can fail if the child died or the pipe really
# wasn't ready (select returns a hint only). The fd has
# been made non-blocking by spawn_child.
try:
ready_byte = os.read(self.fd, 1)
if not ready_byte:
raise IOError('null read from child')
assert ready_byte == b'1', repr(ready_byte)
except (OSError, IOError) as exc:
if exc.errno == errno.EWOULDBLOCK:
# select was wrong and fd not ready. Child might
# still be busy so keep it alive (don't close).
return
self.log('error while getting child status: %s' % exc)
else:
try:
passfd.sendfd(self.fd, conn.fileno())
except IOError as exc:
if exc.errno == errno.EPIPE:
# broken pipe, child died?
self.log('EPIPE passing fd to child')
else:
# some other error that we don't expect
self.log('IOError passing fd to child: %s' % exc.errno)
else:
# fd was apparently passed okay to the child.
# The child could die before completing the
# request but that's not our problem anymore.
self.last_used = time.time()
conn.close()
del self.queue[0]
return
# We have failed to pass the fd to the child. Since the
# child is not behaving how we expect, we close 'fd'. That
# will cause the child to die (if it hasn't already). We will
# reap the exit status in reap_children() and remove the Child()
# object from the 'children' list.
self.close()
def process(self, conn):
# Try to read the single byte written by the child.
# This can fail if the child died or the socket really
# wasn't ready (select returns a hint only). The fd has
# been made non-blocking by spawn_child.
try:
ready_byte = os.read(self.fd, 1)
if not ready_byte:
raise IOError('null read from child')
assert ready_byte == b"1", repr(ready_byte)
except (OSError, IOError) as exc:
if exc.errno == errno.EWOULDBLOCK:
# select was wrong and fd not ready. Child might
# still be busy so keep it alive (don't close).
return False
else:
self.log('error while getting child status: %s' % exc)
else:
# The byte was read okay, now we need to pass the fd
# of the request to the child. This can also fail
# if the child died. Again, if this fails we fall
# through to the "reap_children" logic and will
# retry the select call.
try:
passfd.sendfd(self.fd, conn.fileno())
except IOError as exc:
if exc.errno == errno.EPIPE:
# broken pipe, child died?
self.log('EPIPE passing fd to child')
else:
# some other error that we don't expect
self.log('IOError passing fd to child: %s' % exc.errno)
else:
# fd was apparently passed okay to the child.
# The child could die before completing the
# request but that's not our problem anymore.
return True
# We have failed to pass the fd to the child. Since the
# child is not behaving how we expect, we close 'fd'. That
# will cause the child to die (if it hasn't already). We will
# reap the exit status in reap_children() and remove the Child()
# object from the 'children' list.
self.close()
return False # did not pass fd successfully
assert ready_byte == "1", repr(ready_byte)
except socket.error, exc:
if exc[0] == errno.EWOULDBLOCK:
pass # select was wrong
else:
raise
except (OSError, IOError):
pass # child died?
else:
# The byte was read okay, now we need to pass the fd
# of the request to the child. This can also fail
# if the child died. Again, if this fails we fall
# through to the "reap_children" logic and will
# retry the select call.
try:
passfd.sendfd(child.fd, conn.fileno())
except IOError, exc:
if exc.errno == errno.EPIPE:
pass # broken pipe, child died?
else:
raise
else:
# fd was apparently passed okay to the child.
# The child could die before completing the
# request but that's not our problem anymore.
return
# didn't find any child, check if any died
self.reap_children()
# start more children if we haven't met max_children limit
assert ready_byte == "1", repr(ready_byte)
except socket.error, exc:
if exc[0] == errno.EWOULDBLOCK:
pass # select was wrong
else:
raise
except (OSError, IOError):
pass # child died?
else:
# The byte was read okay, now we need to pass the fd
# of the request to the child. This can also fail
# if the child died. Again, if this fails we fall
# through to the "reap_children" logic and will
# retry the select call.
try:
passfd.sendfd(child.fd, conn.fileno())
except IOError, exc:
if exc.errno == errno.EPIPE:
pass # broken pipe, child died?
else:
raise
else:
# fd was apparently passed okay to the child.
# The child could die before completing the
# request but that's not our problem anymore.
return
# didn't find any child, check if any died
self.reap_children()
# start more children if we haven't met max_children limit
#
# fork() off!
#
pid = os.fork()
if pid != 0:
# We're in the parent.
# ioctl() will only pass raw filedescriptors. Find fd of fileObj.
fd = fileObj.fileno()
# Send to the child
os.write(wfd, b'x')
passfd.sendfd(wfd, fd)
# Wait for child to terminate, then exit.
os.waitpid(pid, 0)
fileObj.close()
sys.exit(0)
else:
# We're in the child.
fileObj.close()
print(os.read(rfd, 1))
fd = passfd.recvfd(rfd)
# Reopen the filedescriptor as a Python File-object.