procutil: make stream detection in make_line_buffered more correct and strict
In make_line_buffered(), we don’t want to wrap the stream if we know that lines
get flushed to the underlying raw stream already.
Previously, the heuristic was too optimistic. It assumed that any stream which
is not an instance of io.BufferedIOBase doesn’t need wrapping. However, there
are buffered streams that aren’t instances of io.BufferedIOBase, like
Mercurial’s own winstdout.
The new logic is different in two ways:
First, only for the check, if unwraps any combination of WriteAllWrapper and
winstdout.
Second, it skips wrapping the stream only if it is an instance of io.RawIOBase
(or already wrapped). If it is an instance of io.BufferedIOBase, it gets
wrapped. In any other case, the function raises an exception. This ensures
that, if an unknown stream is passed or we add another wrapper in the future,
we don’t wrap the stream if it’s already line buffered or not wrap the stream
if it’s not line buffered. In fact, this was already helpful during development
of this change. Without it, I possibly would have forgot that WriteAllWrapper
needs to be ignored for the check, leading to unnecessary wrapping if stdout is
unbuffered.
The alternative would have been to always wrap unknown streams. However, I
don’t think that anyone would benefit from being less strict. We can expect
streams from the standard library to be subclassing either io.RawIOBase or
io.BufferedIOBase, so running Mercurial in the standard way should not regress
by this change. Py2exe might replace sys.stdout and sys.stderr, but that
currently breaks Mercurial anyway and also these streams don’t claim to be
interactive, so this function is not called for them.
# server.py - utility and factory of server
#
# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import os
from .i18n import _
from .pycompat import open
from . import (
chgserver,
cmdutil,
commandserver,
error,
hgweb,
pycompat,
util,
)
from .utils import (
procutil,
urlutil,
)
def runservice(
opts,
parentfn=None,
initfn=None,
runfn=None,
logfile=None,
runargs=None,
appendpid=False,
):
'''Run a command as a service.'''
postexecargs = {}
if opts[b'daemon_postexec']:
for inst in opts[b'daemon_postexec']:
if inst.startswith(b'unlink:'):
postexecargs[b'unlink'] = inst[7:]
elif inst.startswith(b'chdir:'):
postexecargs[b'chdir'] = inst[6:]
elif inst != b'none':
raise error.Abort(
_(b'invalid value for --daemon-postexec: %s') % inst
)
# When daemonized on Windows, redirect stdout/stderr to the lockfile (which
# gets cleaned up after the child is up and running), so that the parent can
# read and print the error if this child dies early. See 594dd384803c. On
# other platforms, the child can write to the parent's stdio directly, until
# it is redirected prior to runfn().
if pycompat.iswindows and opts[b'daemon_postexec']:
if b'unlink' in postexecargs and os.path.exists(
postexecargs[b'unlink']
):
procutil.stdout.flush()
procutil.stderr.flush()
fd = os.open(
postexecargs[b'unlink'], os.O_WRONLY | os.O_APPEND | os.O_BINARY
)
try:
os.dup2(fd, procutil.stdout.fileno())
os.dup2(fd, procutil.stderr.fileno())
finally:
os.close(fd)
def writepid(pid):
if opts[b'pid_file']:
if appendpid:
mode = b'ab'
else:
mode = b'wb'
fp = open(opts[b'pid_file'], mode)
fp.write(b'%d\n' % pid)
fp.close()
if opts[b'daemon'] and not opts[b'daemon_postexec']:
# Signal child process startup with file removal
lockfd, lockpath = pycompat.mkstemp(prefix=b'hg-service-')
os.close(lockfd)
try:
if not runargs:
runargs = procutil.hgcmd() + pycompat.sysargv[1:]
runargs.append(b'--daemon-postexec=unlink:%s' % lockpath)
# Don't pass --cwd to the child process, because we've already
# changed directory.
for i in range(1, len(runargs)):
if runargs[i].startswith(b'--cwd='):
del runargs[i]
break
elif runargs[i].startswith(b'--cwd'):
del runargs[i : i + 2]
break
def condfn():
return not os.path.exists(lockpath)
pid = procutil.rundetached(runargs, condfn)
if pid < 0:
# If the daemonized process managed to write out an error msg,
# report it.
if pycompat.iswindows and os.path.exists(lockpath):
with open(lockpath, b'rb') as log:
for line in log:
procutil.stderr.write(line)
raise error.Abort(_(b'child process failed to start'))
writepid(pid)
finally:
util.tryunlink(lockpath)
if parentfn:
return parentfn(pid)
else:
return
if initfn:
initfn()
if not opts[b'daemon']:
writepid(procutil.getpid())
if opts[b'daemon_postexec']:
try:
os.setsid()
except AttributeError:
pass
if b'chdir' in postexecargs:
os.chdir(postexecargs[b'chdir'])
procutil.hidewindow()
procutil.stdout.flush()
procutil.stderr.flush()
nullfd = os.open(os.devnull, os.O_RDWR)
logfilefd = nullfd
if logfile:
logfilefd = os.open(
logfile, os.O_RDWR | os.O_CREAT | os.O_APPEND, 0o666
)
os.dup2(nullfd, procutil.stdin.fileno())
os.dup2(logfilefd, procutil.stdout.fileno())
os.dup2(logfilefd, procutil.stderr.fileno())
stdio = (
procutil.stdin.fileno(),
procutil.stdout.fileno(),
procutil.stderr.fileno(),
)
if nullfd not in stdio:
os.close(nullfd)
if logfile and logfilefd not in stdio:
os.close(logfilefd)
# Only unlink after redirecting stdout/stderr, so Windows doesn't
# complain about a sharing violation.
if b'unlink' in postexecargs:
os.unlink(postexecargs[b'unlink'])
if runfn:
return runfn()
_cmdservicemap = {
b'chgunix': chgserver.chgunixservice,
b'pipe': commandserver.pipeservice,
b'unix': commandserver.unixforkingservice,
}
def _createcmdservice(ui, repo, opts):
mode = opts[b'cmdserver']
try:
servicefn = _cmdservicemap[mode]
except KeyError:
raise error.Abort(_(b'unknown mode %s') % mode)
commandserver.setuplogging(ui, repo)
return servicefn(ui, repo, opts)
def _createhgwebservice(ui, repo, opts):
# this way we can check if something was given in the command-line
if opts.get(b'port'):
opts[b'port'] = urlutil.getport(opts.get(b'port'))
alluis = {ui}
if repo:
baseui = repo.baseui
alluis.update([repo.baseui, repo.ui])
else:
baseui = ui
webconf = opts.get(b'web_conf') or opts.get(b'webdir_conf')
if webconf:
if opts.get(b'subrepos'):
raise error.Abort(_(b'--web-conf cannot be used with --subrepos'))
# load server settings (e.g. web.port) to "copied" ui, which allows
# hgwebdir to reload webconf cleanly
servui = ui.copy()
servui.readconfig(webconf, sections=[b'web'])
alluis.add(servui)
elif opts.get(b'subrepos'):
servui = ui
# If repo is None, hgweb.createapp() already raises a proper abort
# message as long as webconf is None.
if repo:
webconf = dict()
cmdutil.addwebdirpath(repo, b"", webconf)
else:
servui = ui
optlist = (
b"name templates style address port prefix ipv6"
b" accesslog errorlog certificate encoding"
)
for o in optlist.split():
val = opts.get(o, b'')
if val in (None, b''): # should check against default options instead
continue
for u in alluis:
u.setconfig(b"web", o, val, b'serve')
app = hgweb.createapp(baseui, repo, webconf)
return hgweb.httpservice(servui, app, opts)
def createservice(ui, repo, opts):
if opts[b"cmdserver"]:
return _createcmdservice(ui, repo, opts)
else:
return _createhgwebservice(ui, repo, opts)