In my laptop, socket.gethostname() returned my username, and causing one
of python's "make test" regression test to error (test_socket):
======================================================================
ERROR: testSockName (test.test_socket.GeneralModuleTests)
----------------------------------------------------------------------
Traceback (most recent call last):
File
"/var/tmp/portage/dev-lang/python-2.5.4-r3/work/Python-2.5.4/Lib/test/test_socket.py",
line 456, in testSockName
my_ip_addr = socket.gethostbyname(socket.gethostname())
gaierror: (-2, 'Name or service not known')
----------
since on my system socket.gethostname() returns 'lieryan', and since
socket.gethostbyname('lieryan') does not resolve to anything; the test
becomes an error.
My system is Gentoo, but I think this also happened on Ubuntu (still on
this laptop). The trunk failed in similar manner.
Do I have a misconfigured system or is the test faulty?
For convenience, the relevant test code (taken from trunk):
=======================
def testSockName(self):
# Testing getsockname()
port = self._get_unused_port()
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind(("0.0.0.0", port))
name = sock.getsockname()
# XXX(nnorwitz): http://tinyurl.com/os5jz seems to indicate
# it reasonable to get the host's addr in addition to 0.0.0.0.
# At least for eCos. This is required for the S/390 to pass.
my_ip_addr = socket.gethostbyname(socket.gethostname())
self.assertTrue(name[0] in ("0.0.0.0", my_ip_addr), '%s invalid' %
name[0])
self.assertEqual(name[1], port)
=======================
lier...@lieryan ~/Desktop/pythontrunk/trunk $ ./python -m test.regrtest
test_socket
Could not find '/home/lieryan/Desktop/pythontrunk/trunk/Lib/test' in
sys.path to remove it
test_socket
test test_socket failed -- Traceback (most recent call last):
File
"/home/lieryan/Desktop/pythontrunk/trunk/Lib/test/test_socket.py", line
493, in testSockName
my_ip_addr = socket.gethostbyname(socket.gethostname())
gaierror: [Errno -2] Name or service not known
1 test failed:
test_socket
I tracked the code for socket.gethostname() and socket.gethostbyname()
and found that they are simply a wrapper for gethostname() from #import
<unistd.h> (http://linux.die.net/man/2/gethostname) and gethostbyname()
from #import <netdb.h> (http://linux.die.net/man/3/gethostbyname). A
simple test in C found that the C's equivalent to
gethostbyname(gethostname()) returns a null pointer (used to indicate
error, per documentation).
So, the question is: what is socket.gethostname() is supposed to return
that will be a valid argument for socket.gethostbyname()?
PS: I found an MSDN article by Microsoft stating that
gethostbyname(gethostname) is guaranteed to always succeed
(http://msdn.microsoft.com/en-us/library/ms738527(VS.85).aspx); is this
guarantee also true in linux?
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