Hi Guru! Thanks for applying the patches so far. I cannot see the call to ovs.daemon_windows in this patch; the calls to daemon_windows were added in next patch (13/17) where the porting to windows was added. Also daemon_unix.py has only some minor changes (comments and alignment) but I will include them in the commit description.
I will resend this patch after I add [diff] renames = copies Thanks, Paul From: Guru Shetty [mailto:g...@ovn.org] Sent: Wednesday, August 3, 2016 7:07 PM To: Paul Boca Cc: dev@openvswitch.org Subject: Re: [ovs-dev] [PATCH V11 12/17] python tests: Prepare porting Python daemon on Windows On 2 August 2016 at 10:45, Paul Boca <pb...@cloudbasesolutions.com<mailto:pb...@cloudbasesolutions.com>> wrote: Renamed daemon.py to daemon_unix.py and implemented a wrapper over it. Signed-off-by: Paul-Daniel Boca <pb...@cloudbasesolutions.com<mailto:pb...@cloudbasesolutions.com>> Acked-by: Alin Gabriel Serdean <aserd...@cloudbasesolutions.com<mailto:aserd...@cloudbasesolutions.com>> As a standalone commit, this likely fails because it calls ovs.daemon_windows which does not exist. I also notice that you have made additional changes in daemon_unix.py. Please do that as a separate commit with proper commit message. Also, to be sure, please add the following to your .gitconfig [diff] renames = copies --- V8: Initial commit. V9: No changes V10: Fixed exception on Unix V11: No changes --- python/automake.mk<http://automake.mk> | 1 + python/ovs/daemon.py | 489 ++---------------------------------------- python/ovs/daemon_unix.py | 530 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 551 insertions(+), 469 deletions(-) create mode 100644 python/ovs/daemon_unix.py diff --git a/python/automake.mk<http://automake.mk> b/python/automake.mk<http://automake.mk> index 1c8fa38..4d3fcb6 100644 --- a/python/automake.mk<http://automake.mk> +++ b/python/automake.mk<http://automake.mk> @@ -11,6 +11,7 @@ ovstest_pyfiles = \ ovs_pyfiles = \ python/ovs/__init__.py \ python/ovs/daemon.py \ + python/ovs/daemon_unix.py \ python/ovs/fcntl_win.py \ python/ovs/db/__init__.py \ python/ovs/db/data.py \ diff --git a/python/ovs/daemon.py b/python/ovs/daemon.py index bd06195..b1d6c36 100644 --- a/python/ovs/daemon.py +++ b/python/ovs/daemon.py @@ -1,4 +1,4 @@ -# Copyright (c) 2010, 2011, 2012 Nicira, Inc. +# Copyright (c) 2016 Cloudbase Solutions Srl # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. @@ -12,515 +12,66 @@ # See the License for the specific language governing permissions and # limitations under the License. -import errno -import fcntl -import os -import resource -import signal import sys -import time -import ovs.dirs -import ovs.fatal_signal -import ovs.process -import ovs.socket_util -import ovs.timeval -import ovs.util -import ovs.vlog +# This is only a wrapper over Linux implementations +if sys.platform != "win32": + import ovs.daemon_unix as daemon_util -vlog = ovs.vlog.Vlog("daemon") - -# --detach: Should we run in the background? -_detach = False - -# --pidfile: Name of pidfile (null if none). -_pidfile = None - -# Our pidfile's inode and device, if we have created one. -_pidfile_dev = None -_pidfile_ino = None - -# --overwrite-pidfile: Create pidfile even if one already exists and is locked? -_overwrite_pidfile = False - -# --no-chdir: Should we chdir to "/"? -_chdir = True - -# --monitor: Should a supervisory process monitor the daemon and restart it if -# it dies due to an error signal? -_monitor = False - -# File descriptor used by daemonize_start() and daemonize_complete(). -_daemonize_fd = None - -RESTART_EXIT_CODE = 5 +RESTART_EXIT_CODE = daemon_util.RESTART_EXIT_CODE def make_pidfile_name(name): - """Returns the file name that would be used for a pidfile if 'name' were - provided to set_pidfile().""" - if name is None or name == "": - return "%s/%s.pid" % (ovs.dirs.RUNDIR, ovs.util.PROGRAM_NAME) - else: - return ovs.util.abs_file_name(ovs.dirs.RUNDIR, name) + return daemon_util.make_pidfile_name(name) def set_pidfile(name): - """Sets up a following call to daemonize() to create a pidfile named - 'name'. If 'name' begins with '/', then it is treated as an absolute path. - Otherwise, it is taken relative to ovs.util.RUNDIR, which is - $(prefix)/var/run by default. - - If 'name' is null, then ovs.util.PROGRAM_NAME followed by ".pid" is - used.""" - global _pidfile - _pidfile = make_pidfile_name(name) + daemon_util.set_pidfile(name) def set_no_chdir(): - """Sets that we do not chdir to "/".""" - global _chdir - _chdir = False + daemon_util.set_no_chdir() def ignore_existing_pidfile(): - """Normally, daemonize() or daemonize_start() will terminate the program - with a message if a locked pidfile already exists. If this function is - called, an existing pidfile will be replaced, with a warning.""" - global _overwrite_pidfile - _overwrite_pidfile = True + daemon_util.ignore_existing_pidfile() def set_detach(): - """Sets up a following call to daemonize() to detach from the foreground - session, running this process in the background.""" - global _detach - _detach = True + daemon_util.set_detach() def get_detach(): - """Will daemonize() really detach?""" - return _detach + return daemon_util.get_detach() def set_monitor(): - """Sets up a following call to daemonize() to fork a supervisory process to - monitor the daemon and restart it if it dies due to an error signal.""" - global _monitor - _monitor = True - - -def _fatal(msg): - vlog.err(msg) - sys.stderr.write("%s\n" % msg) - sys.exit(1) - - -def _make_pidfile(): - """If a pidfile has been configured, creates it and stores the running - process's pid in it. Ensures that the pidfile will be deleted when the - process exits.""" - pid = os.getpid() - - # Create a temporary pidfile. - tmpfile = "%s.tmp%d" % (_pidfile, pid) - ovs.fatal_signal.add_file_to_unlink(tmpfile) - try: - # This is global to keep Python from garbage-collecting and - # therefore closing our file after this function exits. That would - # unlock the lock for us, and we don't want that. - global file_handle - - file_handle = open(tmpfile, "w") - except IOError as e: - _fatal("%s: create failed (%s)" % (tmpfile, e.strerror)) - - try: - s = os.fstat(file_handle.fileno()) - except IOError as e: - _fatal("%s: fstat failed (%s)" % (tmpfile, e.strerror)) - - try: - file_handle.write("%s\n" % pid) - file_handle.flush() - except OSError as e: - _fatal("%s: write failed: %s" % (tmpfile, e.strerror)) - - try: - fcntl.lockf(file_handle, fcntl.LOCK_EX | fcntl.LOCK_NB) - except IOError as e: - _fatal("%s: fcntl failed: %s" % (tmpfile, e.strerror)) - - # Rename or link it to the correct name. - if _overwrite_pidfile: - try: - os.rename(tmpfile, _pidfile) - except OSError as e: - _fatal("failed to rename \"%s\" to \"%s\" (%s)" - % (tmpfile, _pidfile, e.strerror)) - else: - while True: - try: - os.link(tmpfile, _pidfile) - error = 0 - except OSError as e: - error = e.errno - if error == errno.EEXIST: - _check_already_running() - elif error != errno.EINTR: - break - if error: - _fatal("failed to link \"%s\" as \"%s\" (%s)" - % (tmpfile, _pidfile, os.strerror(error))) - - # Ensure that the pidfile will get deleted on exit. - ovs.fatal_signal.add_file_to_unlink(_pidfile) - - # Delete the temporary pidfile if it still exists. - if not _overwrite_pidfile: - error = ovs.fatal_signal.unlink_file_now(tmpfile) - if error: - _fatal("%s: unlink failed (%s)" % (tmpfile, os.strerror(error))) - - global _pidfile_dev - global _pidfile_ino - _pidfile_dev = s.st_dev - _pidfile_ino = s.st_ino + daemon_util.set_monitor() def daemonize(): - """If configured with set_pidfile() or set_detach(), creates the pid file - and detaches from the foreground session.""" - daemonize_start() - daemonize_complete() - - -def _waitpid(pid, options): - while True: - try: - return os.waitpid(pid, options) - except OSError as e: - if e.errno == errno.EINTR: - pass - return -e.errno, 0 - - -def _fork_and_wait_for_startup(): - try: - rfd, wfd = os.pipe() - except OSError as e: - sys.stderr.write("pipe failed: %s\n" % os.strerror(e.errno)) - sys.exit(1) - - try: - pid = os.fork() - except OSError as e: - sys.stderr.write("could not fork: %s\n" % os.strerror(e.errno)) - sys.exit(1) - - if pid > 0: - # Running in parent process. - os.close(wfd) - ovs.fatal_signal.fork() - while True: - try: - s = os.read(rfd, 1) - error = 0 - except OSError as e: - s = "" - error = e.errno - if error != errno.EINTR: - break - if len(s) != 1: - retval, status = _waitpid(pid, 0) - if retval == pid: - if os.WIFEXITED(status) and os.WEXITSTATUS(status): - # Child exited with an error. Convey the same error to - # our parent process as a courtesy. - sys.exit(os.WEXITSTATUS(status)) - else: - sys.stderr.write("fork child failed to signal " - "startup (%s)\n" - % ovs.process.status_msg(status)) - else: - assert retval < 0 - sys.stderr.write("waitpid failed (%s)\n" - % os.strerror(-retval)) - sys.exit(1) - - os.close(rfd) - else: - # Running in parent process. - os.close(rfd) - ovs.timeval.postfork() - - global _daemonize_fd - _daemonize_fd = wfd - return pid - - -def _fork_notify_startup(fd): - if fd is not None: - error, bytes_written = ovs.socket_util.write_fully(fd, "0") - if error: - sys.stderr.write("could not write to pipe\n") - sys.exit(1) - os.close(fd) - - -def _should_restart(status): - global RESTART_EXIT_CODE - - if os.WIFEXITED(status) and os.WEXITSTATUS(status) == RESTART_EXIT_CODE: - return True - - if os.WIFSIGNALED(status): - for signame in ("SIGABRT", "SIGALRM", "SIGBUS", "SIGFPE", "SIGILL", - "SIGPIPE", "SIGSEGV", "SIGXCPU", "SIGXFSZ"): - if os.WTERMSIG(status) == getattr(signal, signame, None): - return True - return False - - -def _monitor_daemon(daemon_pid): - # XXX should log daemon's stderr output at startup time - # XXX should use setproctitle module if available - last_restart = None - while True: - retval, status = _waitpid(daemon_pid, 0) - if retval < 0: - sys.stderr.write("waitpid failed\n") - sys.exit(1) - elif retval == daemon_pid: - status_msg = ("pid %d died, %s" - % (daemon_pid, ovs.process.status_msg(status))) - - if _should_restart(status): - if os.WCOREDUMP(status): - # Disable further core dumps to save disk space. - try: - resource.setrlimit(resource.RLIMIT_CORE, (0, 0)) - except resource.error: - vlog.warn("failed to disable core dumps") - - # Throttle restarts to no more than once every 10 seconds. - if (last_restart is not None and - ovs.timeval.msec() < last_restart + 10000): - vlog.warn("%s, waiting until 10 seconds since last " - "restart" % status_msg) - while True: - now = ovs.timeval.msec() - wakeup = last_restart + 10000 - if now > wakeup: - break - sys.stdout.write("sleep %f\n" % ( - (wakeup - now) / 1000.0)) - time.sleep((wakeup - now) / 1000.0) - last_restart = ovs.timeval.msec() - - vlog.err("%s, restarting" % status_msg) - daemon_pid = _fork_and_wait_for_startup() - if not daemon_pid: - break - else: - vlog.info<http://vlog.info>("%s, exiting" % status_msg) - sys.exit(0) - - # Running in new daemon process. - - -def _close_standard_fds(): - """Close stdin, stdout, stderr. If we're started from e.g. an SSH session, - then this keeps us from holding that session open artificially.""" - null_fd = ovs.socket_util.get_null_fd() - if null_fd >= 0: - os.dup2(null_fd, 0) - os.dup2(null_fd, 1) - os.dup2(null_fd, 2) + daemon_util.daemonize() def daemonize_start(): - """If daemonization is configured, then starts daemonization, by forking - and returning in the child process. The parent process hangs around until - the child lets it know either that it completed startup successfully (by - calling daemon_complete()) or that it failed to start up (by exiting with a - nonzero exit code).""" - - if _detach: - if _fork_and_wait_for_startup() > 0: - # Running in parent process. - sys.exit(0) - - # Running in daemon or monitor process. - os.setsid() - - if _monitor: - saved_daemonize_fd = _daemonize_fd - daemon_pid = _fork_and_wait_for_startup() - if daemon_pid > 0: - # Running in monitor process. - _fork_notify_startup(saved_daemonize_fd) - _close_standard_fds() - _monitor_daemon(daemon_pid) - # Running in daemon process - - if _pidfile: - _make_pidfile() + daemon_util.daemonize_start() def daemonize_complete(): - """If daemonization is configured, then this function notifies the parent - process that the child process has completed startup successfully.""" - _fork_notify_startup(_daemonize_fd) - - if _detach: - if _chdir: - os.chdir("/") - _close_standard_fds() + daemon_util.daemonize_complete() def usage(): - sys.stdout.write(""" -Daemon options: - --detach run in background as daemon - --no-chdir do not chdir to '/' - --pidfile[=FILE] create pidfile (default: %s/%s.pid) - --overwrite-pidfile with --pidfile, start even if already running -""" % (ovs.dirs.RUNDIR, ovs.util.PROGRAM_NAME)) - - -def __read_pidfile(pidfile, delete_if_stale): - if _pidfile_dev is not None: - try: - s = os.stat(pidfile) - if s.st_ino == _pidfile_ino and s.st_dev == _pidfile_dev: - # It's our own pidfile. We can't afford to open it, - # because closing *any* fd for a file that a process - # has locked also releases all the locks on that file. - # - # Fortunately, we know the associated pid anyhow. - return os.getpid() - except OSError: - pass + daemon_util.usage() - try: - file_handle = open(pidfile, "r+") - except IOError as e: - if e.errno == errno.ENOENT and delete_if_stale: - return 0 - vlog.warn("%s: open: %s" % (pidfile, e.strerror)) - return -e.errno - # Python fcntl doesn't directly support F_GETLK so we have to just try - # to lock it. - try: - fcntl.lockf(file_handle, fcntl.LOCK_EX | fcntl.LOCK_NB) - - # pidfile exists but wasn't locked by anyone. Now we have the lock. - if not delete_if_stale: - file_handle.close() - vlog.warn("%s: pid file is stale" % pidfile) - return -errno.ESRCH - - # Is the file we have locked still named 'pidfile'? - try: - raced = False - s = os.stat(pidfile) - s2 = os.fstat(file_handle.fileno()) - if s.st_ino != s2.st_ino or s.st_dev != s2.st_dev: - raced = True - except IOError: - raced = True - if raced: - vlog.warn("%s: lost race to delete pidfile" % pidfile) - return -errno.EALREADY - - # We won the right to delete the stale pidfile. - try: - os.unlink(pidfile) - except IOError as e: - vlog.warn("%s: failed to delete stale pidfile (%s)" - % (pidfile, e.strerror)) - return -e.errno - else: - vlog.dbg("%s: deleted stale pidfile" % pidfile) - file_handle.close() - return 0 - except IOError as e: - if e.errno not in [errno.EACCES, errno.EAGAIN]: - vlog.warn("%s: fcntl: %s" % (pidfile, e.strerror)) - return -e.errno - - # Someone else has the pidfile locked. - try: - try: - error = int(file_handle.readline()) - except IOError as e: - vlog.warn("%s: read: %s" % (pidfile, e.strerror)) - error = -e.errno - except ValueError: - vlog.warn("%s does not contain a pid" % pidfile) - error = -errno.EINVAL - - return error - finally: - try: - file_handle.close() - except IOError: - pass - - -def read_pidfile(pidfile): - """Opens and reads a PID from 'pidfile'. Returns the positive PID if - successful, otherwise a negative errno value.""" - return __read_pidfile(pidfile, False) - - -def _check_already_running(): - pid = __read_pidfile(_pidfile, True) - if pid > 0: - _fatal("%s: already running as pid %d, aborting" % (_pidfile, pid)) - elif pid < 0: - _fatal("%s: pidfile check failed (%s), aborting" - % (_pidfile, os.strerror(pid))) +def read_pidfile(pidfile_name): + return daemon_util.read_pidfile(pidfile_name) def add_args(parser): - """Populates 'parser', an ArgumentParser allocated using the argparse - module, with the command line arguments required by the daemon module.""" - - pidfile = make_pidfile_name(None) - - group = parser.add_argument_group(title="Daemon Options") - group.add_argument("--detach", action="store_true", - help="Run in background as a daemon.") - group.add_argument("--no-chdir", action="store_true", - help="Do not chdir to '/'.") - group.add_argument("--monitor", action="store_true", - help="Monitor %s process." % ovs.util.PROGRAM_NAME) - group.add_argument("--pidfile", nargs="?", const=pidfile, - help="Create pidfile (default %s)." % pidfile) - group.add_argument("--overwrite-pidfile", action="store_true", - help="With --pidfile, start even if already running.") + daemon_util.add_args(parser) def handle_args(args): - """Handles daemon module settings in 'args'. 'args' is an object - containing values parsed by the parse_args() method of ArgumentParser. The - parent ArgumentParser should have been prepared by add_args() before - calling parse_args().""" - - if args.detach: - set_detach() - - if args.no_chdir: - set_no_chdir() - - if args.pidfile: - set_pidfile(args.pidfile) - - if args.overwrite_pidfile: - ignore_existing_pidfile() - - if args.monitor: - set_monitor() + daemon_util.handle_args(args) diff --git a/python/ovs/daemon_unix.py b/python/ovs/daemon_unix.py new file mode 100644 index 0000000..3bd56af --- /dev/null +++ b/python/ovs/daemon_unix.py @@ -0,0 +1,530 @@ +# Copyright (c) 2010, 2011, 2012, 2016 Nicira, Inc. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at: +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +import errno +import os +import signal +import sys +import time + +import ovs.dirs +import ovs.fatal_signal +import ovs.process +import ovs.socket_util +import ovs.timeval +import ovs.util +import ovs.vlog + +import fcntl +import resource + +vlog = ovs.vlog.Vlog("daemon") + +# --detach: Should we run in the background? +_detach = False + +# --pidfile: Name of pidfile (null if none). +_pidfile = None + +# Our pidfile's inode and device, if we have created one. +_pidfile_dev = None +_pidfile_ino = None + +# --overwrite-pidfile: Create pidfile even if one already exists and is locked? +_overwrite_pidfile = False + +# --no-chdir: Should we chdir to "/"? +_chdir = True + +# --monitor: Should a supervisory process monitor the daemon and restart it if +# it dies due to an error signal? +_monitor = False + +# File descriptor used by daemonize_start() and daemonize_complete(). +_daemonize_fd = None + + +RESTART_EXIT_CODE = 5 + + +def make_pidfile_name(name): + """Returns the file name that would be used for a pidfile if 'name' were + provided to set_pidfile().""" + if name is None or name == "": + return "%s/%s.pid" % (ovs.dirs.RUNDIR, ovs.util.PROGRAM_NAME) + else: + return ovs.util.abs_file_name(ovs.dirs.RUNDIR, name) + + +def set_pidfile(name): + """Sets up a following call to daemonize() to create a pidfile named + 'name'. If 'name' begins with '/', then it is treated as an absolute path. + Otherwise, it is taken relative to ovs.util.RUNDIR, which is + $(prefix)/var/run by default. + + If 'name' is null, then ovs.util.PROGRAM_NAME followed by ".pid" is + used.""" + global _pidfile + _pidfile = make_pidfile_name(name) + + +def set_no_chdir(): + """Sets that we do not chdir to "/".""" + global _chdir + _chdir = False + + +def ignore_existing_pidfile(): + """Normally, daemonize() or daemonize_start() will terminate the program + with a message if a locked pidfile already exists. If this function is + called, an existing pidfile will be replaced, with a warning.""" + global _overwrite_pidfile + _overwrite_pidfile = True + + +def set_detach(): + """Sets up a following call to daemonize() to detach from the foreground + session, running this process in the background.""" + global _detach + _detach = True + + +def get_detach(): + """Will daemonize() really detach?""" + return _detach + + +def set_monitor(): + """Sets up a following call to daemonize() to fork a supervisory process to + monitor the daemon and restart it if it dies due to an error signal.""" + global _monitor + _monitor = True + + +def _fatal(msg): + vlog.err(msg) + sys.stderr.write("%s\n" % msg) + sys.exit(1) + + +def _make_pidfile(): + """If a pidfile has been configured, creates it and stores the running + process's pid in it. Ensures that the pidfile will be deleted when the + process exits.""" + pid = os.getpid() + + # Create a temporary pidfile. + tmpfile = "%s.tmp%d" % (_pidfile, pid) + ovs.fatal_signal.add_file_to_unlink(tmpfile) + + try: + # This is global to keep Python from garbage-collecting and + # therefore closing our file after this function exits. That would + # unlock the lock for us, and we don't want that. + global file_handle + + file_handle = open(tmpfile, "w") + except IOError as e: + _fatal("%s: create failed (%s)" % (tmpfile, e.strerror)) + + try: + s = os.fstat(file_handle.fileno()) + except IOError as e: + _fatal("%s: fstat failed (%s)" % (tmpfile, e.strerror)) + + try: + file_handle.write("%s\n" % pid) + file_handle.flush() + except OSError as e: + _fatal("%s: write failed: %s" % (tmpfile, e.strerror)) + + try: + fcntl.lockf(file_handle, fcntl.LOCK_EX | fcntl.LOCK_NB) + except IOError as e: + _fatal("%s: fcntl failed: %s" % (tmpfile, e.strerror)) + + # Rename or link it to the correct name. + if _overwrite_pidfile: + try: + os.rename(tmpfile, _pidfile) + except OSError as e: + _fatal("failed to rename \"%s\" to \"%s\" (%s)" + % (tmpfile, _pidfile, e.strerror)) + else: + while True: + try: + os.link(tmpfile, _pidfile) + error = 0 + except OSError as e: + error = e.errno + if error == errno.EEXIST: + _check_already_running() + elif error != errno.EINTR: + break + if error: + _fatal("failed to link \"%s\" as \"%s\" (%s)" + % (tmpfile, _pidfile, os.strerror(error))) + + # Ensure that the pidfile will get deleted on exit. + ovs.fatal_signal.add_file_to_unlink(_pidfile) + + # Delete the temporary pidfile if it still exists. + if not _overwrite_pidfile: + error = ovs.fatal_signal.unlink_file_now(tmpfile) + if error: + _fatal("%s: unlink failed (%s)" + % (tmpfile, os.strerror(error))) + + global _pidfile_dev + global _pidfile_ino + _pidfile_dev = s.st_dev + _pidfile_ino = s.st_ino + + +def daemonize(): + """If configured with set_pidfile() or set_detach(), creates the pid file + and detaches from the foreground session.""" + daemonize_start() + daemonize_complete() + + +def _waitpid(pid, options): + while True: + try: + return os.waitpid(pid, options) + except OSError as e: + if e.errno == errno.EINTR: + pass + return -e.errno, 0 + + +def _fork_and_wait_for_startup(): + try: + rfd, wfd = os.pipe() + except OSError as e: + sys.stderr.write("pipe failed: %s\n" % os.strerror(e.errno)) + sys.exit(1) + + try: + pid = os.fork() + except OSError as e: + sys.stderr.write("could not fork: %s\n" % os.strerror(e.errno)) + sys.exit(1) + + if pid > 0: + # Running in parent process. + os.close(wfd) + ovs.fatal_signal.fork() + while True: + try: + s = os.read(rfd, 1) + error = 0 + except OSError as e: + s = "" + error = e.errno + if error != errno.EINTR: + break + if len(s) != 1: + retval, status = _waitpid(pid, 0) + if retval == pid: + if os.WIFEXITED(status) and os.WEXITSTATUS(status): + # Child exited with an error. Convey the same error to + # our parent process as a courtesy. + sys.exit(os.WEXITSTATUS(status)) + else: + sys.stderr.write("fork child failed to signal " + "startup (%s)\n" + % ovs.process.status_msg(status)) + else: + assert retval < 0 + sys.stderr.write("waitpid failed (%s)\n" + % os.strerror(-retval)) + sys.exit(1) + + os.close(rfd) + else: + # Running in child process. + os.close(rfd) + ovs.timeval.postfork() + + global _daemonize_fd + _daemonize_fd = wfd + return pid + + +def _fork_notify_startup(fd): + if fd is not None: + error, bytes_written = ovs.socket_util.write_fully(fd, "0") + if error: + sys.stderr.write("could not write to pipe\n") + sys.exit(1) + os.close(fd) + + +def _should_restart(status): + global RESTART_EXIT_CODE + + if os.WIFEXITED(status) and os.WEXITSTATUS(status) == RESTART_EXIT_CODE: + return True + + if os.WIFSIGNALED(status): + for signame in ("SIGABRT", "SIGALRM", "SIGBUS", "SIGFPE", "SIGILL", + "SIGPIPE", "SIGSEGV", "SIGXCPU", "SIGXFSZ"): + if os.WTERMSIG(status) == getattr(signal, signame, None): + return True + return False + + +def _monitor_daemon(daemon_pid): + # XXX should log daemon's stderr output at startup time + # XXX should use setproctitle module if available + last_restart = None + while True: + retval, status = _waitpid(daemon_pid, 0) + if retval < 0: + sys.stderr.write("waitpid failed\n") + sys.exit(1) + elif retval == daemon_pid: + status_msg = ("pid %d died, %s" + % (daemon_pid, ovs.process.status_msg(status))) + + if _should_restart(status): + if os.WCOREDUMP(status): + # Disable further core dumps to save disk space. + try: + resource.setrlimit(resource.RLIMIT_CORE, (0, 0)) + except resource.error: + vlog.warn("failed to disable core dumps") + + # Throttle restarts to no more than once every 10 seconds. + if (last_restart is not None and + ovs.timeval.msec() < last_restart + 10000): + vlog.warn("%s, waiting until 10 seconds since last " + "restart" % status_msg) + while True: + now = ovs.timeval.msec() + wakeup = last_restart + 10000 + if now > wakeup: + break + sys.stdout.write("sleep %f\n" % ( + (wakeup - now) / 1000.0)) + time.sleep((wakeup - now) / 1000.0) + last_restart = ovs.timeval.msec() + + vlog.err("%s, restarting" % status_msg) + daemon_pid = _fork_and_wait_for_startup() + if not daemon_pid: + break + else: + vlog.info<http://vlog.info>("%s, exiting" % status_msg) + sys.exit(0) + + # Running in new daemon process. + + +def _close_standard_fds(): + """Close stdin, stdout, stderr. If we're started from e.g. an SSH session, + then this keeps us from holding that session open artificially.""" + null_fd = ovs.socket_util.get_null_fd() + if null_fd >= 0: + os.dup2(null_fd, 0) + os.dup2(null_fd, 1) + os.dup2(null_fd, 2) + + +def daemonize_start(): + """If daemonization is configured, then starts daemonization, by forking + and returning in the child process. The parent process hangs around until + the child lets it know either that it completed startup successfully (by + calling daemon_complete()) or that it failed to start up (by exiting with a + nonzero exit code).""" + + if _detach: + if _fork_and_wait_for_startup() > 0: + # Running in parent process. + sys.exit(0) + + # Running in daemon or monitor process. + os.setsid() + + if _monitor: + saved_daemonize_fd = _daemonize_fd + daemon_pid = _fork_and_wait_for_startup() + if daemon_pid > 0: + # Running in monitor process. + _fork_notify_startup(saved_daemonize_fd) + _close_standard_fds() + _monitor_daemon(daemon_pid) + # Running in daemon process + + if _pidfile: + _make_pidfile() + + +def daemonize_complete(): + """If daemonization is configured, then this function notifies the parent + process that the child process has completed startup successfully.""" + _fork_notify_startup(_daemonize_fd) + + if _detach: + if _chdir: + os.chdir("/") + _close_standard_fds() + + +def usage(): + sys.stdout.write(""" +Daemon options: + --detach run in background as daemon + --no-chdir do not chdir to '/' + --pidfile[=FILE] create pidfile (default: %s/%s.pid) + --overwrite-pidfile with --pidfile, start even if already running +""" % (ovs.dirs.RUNDIR, ovs.util.PROGRAM_NAME)) + + +def __read_pidfile(pidfile, delete_if_stale): + if _pidfile_dev is not None: + try: + s = os.stat(pidfile) + if s.st_ino == _pidfile_ino and s.st_dev == _pidfile_dev: + # It's our own pidfile. We can't afford to open it, + # because closing *any* fd for a file that a process + # has locked also releases all the locks on that file. + # + # Fortunately, we know the associated pid anyhow. + return os.getpid() + except OSError: + pass + + try: + file_handle = open(pidfile, "r+") + except IOError as e: + if e.errno == errno.ENOENT and delete_if_stale: + return 0 + vlog.warn("%s: open: %s" % (pidfile, e.strerror)) + return -e.errno + + # Python fcntl doesn't directly support F_GETLK so we have to just try + # to lock it. + try: + fcntl.lockf(file_handle, fcntl.LOCK_EX | fcntl.LOCK_NB) + + # pidfile exists but wasn't locked by anyone. Now we have the lock. + if not delete_if_stale: + file_handle.close() + vlog.warn("%s: pid file is stale" % pidfile) + return -errno.ESRCH + + # Is the file we have locked still named 'pidfile'? + try: + raced = False + s = os.stat(pidfile) + s2 = os.fstat(file_handle.fileno()) + if s.st_ino != s2.st_ino or s.st_dev != s2.st_dev: + raced = True + except IOError: + raced = True + if raced: + vlog.warn("%s: lost race to delete pidfile" % pidfile) + return -errno.EALREADY + + # We won the right to delete the stale pidfile. + try: + os.unlink(pidfile) + except IOError as e: + vlog.warn("%s: failed to delete stale pidfile (%s)" + % (pidfile, e.strerror)) + return -e.errno + else: + vlog.dbg("%s: deleted stale pidfile" % pidfile) + file_handle.close() + return 0 + except IOError as e: + if e.errno not in [errno.EACCES, errno.EAGAIN]: + vlog.warn("%s: fcntl: %s" % (pidfile, e.strerror)) + return -e.errno + + # Someone else has the pidfile locked. + try: + try: + error = int(file_handle.readline()) + except IOError as e: + vlog.warn("%s: read: %s" % (pidfile, e.strerror)) + error = -e.errno + except ValueError: + vlog.warn("%s does not contain a pid" % pidfile) + error = -errno.EINVAL + + return error + finally: + try: + file_handle.close() + except IOError: + pass + + +def read_pidfile(pidfile): + """Opens and reads a PID from 'pidfile'. Returns the positive PID if + successful, otherwise a negative errno value.""" + return __read_pidfile(pidfile, False) + + +def _check_already_running(): + pid = __read_pidfile(_pidfile, True) + if pid > 0: + _fatal("%s: already running as pid %d, aborting" % (_pidfile, pid)) + elif pid < 0: + _fatal("%s: pidfile check failed (%s), aborting" + % (_pidfile, os.strerror(pid))) + + +def add_args(parser): + """Populates 'parser', an ArgumentParser allocated using the argparse + module, with the command line arguments required by the daemon module.""" + + pidfile = make_pidfile_name(None) + + group = parser.add_argument_group(title="Daemon Options") + group.add_argument("--detach", action="store_true", + help="Run in background as a daemon.") + group.add_argument("--no-chdir", action="store_true", + help="Do not chdir to '/'.") + group.add_argument("--monitor", action="store_true", + help="Monitor %s process." % ovs.util.PROGRAM_NAME) + group.add_argument("--pidfile", nargs="?", const=pidfile, + help="Create pidfile (default %s)." % pidfile) + group.add_argument("--overwrite-pidfile", action="store_true", + help="With --pidfile, start even if already running.") + + +def handle_args(args): + """Handles daemon module settings in 'args'. 'args' is an object + containing values parsed by the parse_args() method of ArgumentParser. The + parent ArgumentParser should have been prepared by add_args() before + calling parse_args().""" + + if args.detach: + set_detach() + + if args.no_chdir: + set_no_chdir() + + if args.pidfile: + set_pidfile(args.pidfile) + + if args.overwrite_pidfile: + ignore_existing_pidfile() + + if args.monitor: + set_monitor() -- 2.7.2.windows.1 _______________________________________________ dev mailing list dev@openvswitch.org<mailto:dev@openvswitch.org> http://openvswitch.org/mailman/listinfo/dev _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
