worker: rewrite error handling so os._exit covers all cases
Previously the worker error handling is like:
pid = os.fork() --+
if pid == 0: |
.... | problematic
.... --+
try: --+
.... | worker error handling
--+
If a signal arrives when Python is executing the "problematic" lines, an
external error handling (dispatch.py) will take over the control flow and
it's no longer guaranteed "os._exit" is called (see
86cd09bc13ba for why it
is necessary).
This patch rewrites the error handling so it covers all possible code paths
for a worker even during fork.
Note: "os.getpid() == parentpid" is used to test if the process is parent or
not intentionally, instead of checking "pid", because "pid = os.fork()" may
be not atomic - it's possible that that a signal hits the worker before the
assignment completes [1]. The newly added test replaces "os.fork" to
exercise that extreme case.
[1]: CPython compiles "pid = os.fork()" to 2 byte codes: "CALL_FUNCTION" and
"STORE_FAST", so it's probably not atomic:
def f():
pid = os.fork()
dis.dis(f)
2 0 LOAD_GLOBAL 0 (os)
3 LOAD_ATTR 1 (fork)
6 CALL_FUNCTION 0
9 STORE_FAST 0 (pid)
12 LOAD_CONST 0 (None)
15 RETURN_VALUE
from __future__ import absolute_import, print_function
from mercurial import demandimport; demandimport.enable()
from mercurial import (
error,
ui as uimod,
url,
util,
)
urlerr = util.urlerr
urlreq = util.urlreq
class myui(uimod.ui):
def interactive(self):
return False
origui = myui.load()
def writeauth(items):
ui = origui.copy()
for name, value in items.iteritems():
ui.setconfig('auth', name, value)
return ui
def dumpdict(dict):
return '{' + ', '.join(['%s: %s' % (k, dict[k])
for k in sorted(dict.iterkeys())]) + '}'
def test(auth, urls=None):
print('CFG:', dumpdict(auth))
prefixes = set()
for k in auth:
prefixes.add(k.split('.', 1)[0])
for p in prefixes:
for name in ('.username', '.password'):
if (p + name) not in auth:
auth[p + name] = p
auth = dict((k, v) for k, v in auth.iteritems() if v is not None)
ui = writeauth(auth)
def _test(uri):
print('URI:', uri)
try:
pm = url.passwordmgr(ui, urlreq.httppasswordmgrwithdefaultrealm())
u, authinfo = util.url(uri).authinfo()
if authinfo is not None:
pm.add_password(*authinfo)
print(' ', pm.find_user_password('test', u))
except error.Abort:
print(' ','abort')
if not urls:
urls = [
'http://example.org/foo',
'http://example.org/foo/bar',
'http://example.org/bar',
'https://example.org/foo',
'https://example.org/foo/bar',
'https://example.org/bar',
'https://x@example.org/bar',
'https://y@example.org/bar',
]
for u in urls:
_test(u)
print('\n*** Test in-uri schemes\n')
test({'x.prefix': 'http://example.org'})
test({'x.prefix': 'https://example.org'})
test({'x.prefix': 'http://example.org', 'x.schemes': 'https'})
test({'x.prefix': 'https://example.org', 'x.schemes': 'http'})
print('\n*** Test separately configured schemes\n')
test({'x.prefix': 'example.org', 'x.schemes': 'http'})
test({'x.prefix': 'example.org', 'x.schemes': 'https'})
test({'x.prefix': 'example.org', 'x.schemes': 'http https'})
print('\n*** Test prefix matching\n')
test({'x.prefix': 'http://example.org/foo',
'y.prefix': 'http://example.org/bar'})
test({'x.prefix': 'http://example.org/foo',
'y.prefix': 'http://example.org/foo/bar'})
test({'x.prefix': '*', 'y.prefix': 'https://example.org/bar'})
print('\n*** Test user matching\n')
test({'x.prefix': 'http://example.org/foo',
'x.username': None,
'x.password': 'xpassword'},
urls=['http://y@example.org/foo'])
test({'x.prefix': 'http://example.org/foo',
'x.username': None,
'x.password': 'xpassword',
'y.prefix': 'http://example.org/foo',
'y.username': 'y',
'y.password': 'ypassword'},
urls=['http://y@example.org/foo'])
test({'x.prefix': 'http://example.org/foo/bar',
'x.username': None,
'x.password': 'xpassword',
'y.prefix': 'http://example.org/foo',
'y.username': 'y',
'y.password': 'ypassword'},
urls=['http://y@example.org/foo/bar'])
def testauthinfo(fullurl, authurl):
print('URIs:', fullurl, authurl)
pm = urlreq.httppasswordmgrwithdefaultrealm()
pm.add_password(*util.url(fullurl).authinfo()[1])
print(pm.find_user_password('test', authurl))
print('\n*** Test urllib2 and util.url\n')
testauthinfo('http://user@example.com:8080/foo', 'http://example.com:8080/foo')