libvirt/run.in
Daniel P. Berrangé a870801ae1 run: gracefully handle SIGHUP, SIGQUIT, SIGTERM
When using thue 'run' script to launch a daemon, it is intended to
temporarily stop the systemd units and re-start them again after.

When using this script over an SSH connection, it will get SIGHUP
if the connection goes away, and in this case it fails to re-start
the systemd units. We need to catch SIGHUP and turn it into a
normal python exception. For good measure we do the same for
SIGQUIT and SIGTERM too.  SIGINT already gets turned into an
exception by default which we handle.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2022-03-10 08:06:12 +00:00

187 lines
5.3 KiB
Python

#!/usr/bin/env python3
# libvirt 'run' programs locally script
# Copyright (C) 2012-2021 Red Hat, Inc.
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; If not, see
# <http://www.gnu.org/licenses/>.
# ----------------------------------------------------------------------
#
# With this script you can run libvirt programs without needing to
# install them first. You just have to do for example:
#
# ./run virsh [args ...]
#
# Note that this runs the locally compiled copy of virsh which
# is usually want you want.
#
# You can also run the C programs under valgrind like this:
#
# ./run valgrind [valgrind opts...] ./program
#
# or under gdb:
#
# ./run gdb --args ./program
#
# This also works with sudo (eg. if you need root access for libvirt):
#
# sudo ./run virsh list --all
#
# ----------------------------------------------------------------------
import os
import os.path
import random
import signal
import sys
import subprocess
# Function to intelligently prepend a path to an environment variable.
# See https://stackoverflow.com/a/9631350
def prepend(env, varname, extradir):
if varname in os.environ:
env[varname] = extradir + ":" + env[varname]
else:
env[varname] = extradir
here = "@abs_builddir@"
if len(sys.argv) < 2:
print("syntax: %s BINARY [ARGS...]" % sys.argv[0], file=sys.stderr)
sys.exit(1)
prog = sys.argv[1]
args = sys.argv[1:]
env = os.environ
prepend(env, "LD_LIBRARY_PATH", os.path.join(here, "src"))
prepend(env, "PKG_CONFIG_PATH", os.path.join(here, "src"))
prepend(env, "PATH", os.path.join(here, "tools"))
prepend(env, "PATH", os.path.join(here, "src"))
# Ensure that any 3rd party apps using libvirt.so from the build tree get
# files resolved to the build/source tree too. Typically useful for language
# bindings running tests against non-installed libvirt.
env["LIBVIRT_DIR_OVERRIDE"] = "1"
# This is a cheap way to find some use-after-free and uninitialized
# read problems when using glibc.
env["MALLOC_PERTURB_"] = "%d" % random.randint(1, 255)
env["abs_builddir"] = "@abs_builddir@"
env["abs_top_builddir"] = "@abs_top_builddir@"
modular_daemons = [
"virtinterfaced",
"virtlxcd",
"virtnetworkd",
"virtnodedevd",
"virtnwfilterd",
"virtproxyd",
"virtqemud",
"virtsecretd",
"virtstoraged",
"virtvboxd",
"virtvzd",
"virtxend",
]
def is_modular_daemon(name):
return name in modular_daemons
def is_monolithic_daemon(name):
return name == "libvirtd"
def is_systemd_host():
if os.getuid() != 0:
return False
return os.path.exists("/run/systemd/system")
def daemon_units(name):
return [name + suffix for suffix in [
".service", ".socket", "-ro.socket", "-admin.socket"]]
def is_unit_active(name):
ret = subprocess.call(["systemctl", "is-active", "-q", name])
return ret == 0
def change_unit(name, action):
ret = subprocess.call(["systemctl", action, "-q", name])
return ret == 0
try_stop_units = []
if is_systemd_host():
maybe_stopped_units = []
for arg in sys.argv:
name = os.path.basename(arg)
if is_modular_daemon(name):
# Only need to stop libvirtd or this specific modular unit
maybe_stopped_units += daemon_units("libvirtd")
maybe_stopped_units += daemon_units(name)
elif is_monolithic_daemon(name):
# Need to stop libvirtd and/or all modular units
maybe_stopped_units += daemon_units("libvirtd")
for entry in modular_daemons:
maybe_stopped_units += daemon_units(entry)
for unit in maybe_stopped_units:
if is_unit_active(unit):
try_stop_units.append(unit)
if len(try_stop_units) == 0:
# Run the program directly, replacing ourselves
os.execvpe(prog, args, env)
else:
print("Temporarily stopping systemd units...")
stopped_units = []
def sighandler(signum, frame):
raise OSError("Signal %d received, terminating" % signum)
signal.signal(signal.SIGHUP, sighandler)
signal.signal(signal.SIGTERM, sighandler)
signal.signal(signal.SIGQUIT, sighandler)
try:
for unit in try_stop_units:
print(" > %s" % unit)
if not change_unit(unit, "stop"):
raise Exception("Unable to stop '%s'" % unit)
stopped_units.append(unit)
print("Running '%s'..." % str(" ".join(args)))
ret = subprocess.call(args, env=env)
except KeyboardInterrupt:
pass
except Exception as e:
print("%s" % e, file=sys.stderr)
finally:
print("Re-starting original systemd units...")
stopped_units.reverse()
for unit in stopped_units:
print(" > %s" % unit)
if not change_unit(unit, "start"):
print(" ! unable to restart %s" % unit, file=sys.stderr)