annotate contrib/showstack.py @ 29258:6315c1e14f75

sslutil: introduce a function for determining host-specific settings

This patch marks the beginning of a series that introduces a new,
more configurable, per-host security settings mechanism. Currently,
we have global settings (like web.cacerts and the --insecure argument).
We also have per-host settings via [hostfingerprints].

Global security settings are good for defaults, but they don't
provide the amount of control often wanted. For example, an
organization may want to require a particular CA is used for a
particular hostname.

[hostfingerprints] is nice. But it currently assumes SHA-1.
Furthermore, there is no obvious place to put additional per-host
settings.

Subsequent patches will be introducing new mechanisms for defining
security settings, some on a per-host basis. This commits starts
the transition to that world by introducing the _hostsettings
function. It takes a ui and hostname and returns a dict of security
settings. Currently, it limits itself to returning host fingerprint
info.

We foreshadow the future support of non-SHA1 hashing algorithms
for verifying the host fingerprint by making the "certfingerprints"
key a list of tuples instead of a list of hashes.

We add this dict to the hgstate property on the socket and use it
during socket validation for checking fingerprints. There should be
no change in behavior.

# showstack.py - extension to dump a Python stack trace on signal
#
# binds to both SIGQUIT (Ctrl-\) and SIGINFO (Ctrl-T on BSDs)

from __future__ import absolute_import
import signal
import sys
import traceback

def sigshow(*args):
    sys.stderr.write("\n")
    traceback.print_stack(args[1], limit=10, file=sys.stderr)
    sys.stderr.write("----\n")

def extsetup(ui):
    signal.signal(signal.SIGQUIT, sigshow)
    try:
        signal.signal(signal.SIGINFO, sigshow)
    except AttributeError:
        pass