diff options
Diffstat (limited to 'import-layers/yocto-poky/bitbake/lib/bb/daemonize.py')
| -rw-r--r-- | import-layers/yocto-poky/bitbake/lib/bb/daemonize.py | 175 |
1 files changed, 32 insertions, 143 deletions
diff --git a/import-layers/yocto-poky/bitbake/lib/bb/daemonize.py b/import-layers/yocto-poky/bitbake/lib/bb/daemonize.py index ab4a95462..8300d1d0f 100644 --- a/import-layers/yocto-poky/bitbake/lib/bb/daemonize.py +++ b/import-layers/yocto-poky/bitbake/lib/bb/daemonize.py @@ -1,48 +1,14 @@ """ Python Daemonizing helper -Configurable daemon behaviors: - - 1.) The current working directory set to the "/" directory. - 2.) The current file creation mode mask set to 0. - 3.) Close all open files (1024). - 4.) Redirect standard I/O streams to "/dev/null". - -A failed call to fork() now raises an exception. - -References: - 1) Advanced Programming in the Unix Environment: W. Richard Stevens - http://www.apuebook.com/apue3e.html - 2) The Linux Programming Interface: Michael Kerrisk - http://man7.org/tlpi/index.html - 3) Unix Programming Frequently Asked Questions: - http://www.faqs.org/faqs/unix-faq/programmer/faq/ - -Modified to allow a function to be daemonized and return for -bitbake use by Richard Purdie +Originally based on code Copyright (C) 2005 Chad J. Schroeder but now heavily modified +to allow a function to be daemonized and return for bitbake use by Richard Purdie """ -__author__ = "Chad J. Schroeder" -__copyright__ = "Copyright (C) 2005 Chad J. Schroeder" -__version__ = "0.2" - -# Standard Python modules. -import os # Miscellaneous OS interfaces. -import sys # System-specific parameters and functions. - -# Default daemon parameters. -# File mode creation mask of the daemon. -# For BitBake's children, we do want to inherit the parent umask. -UMASK = None - -# Default maximum for the number of available file descriptors. -MAXFD = 1024 - -# The standard I/O file descriptors are redirected to /dev/null by default. -if (hasattr(os, "devnull")): - REDIRECT_TO = os.devnull -else: - REDIRECT_TO = "/dev/null" +import os +import sys +import io +import traceback def createDaemon(function, logfile): """ @@ -65,36 +31,6 @@ def createDaemon(function, logfile): # leader of the new process group, we call os.setsid(). The process is # also guaranteed not to have a controlling terminal. os.setsid() - - # Is ignoring SIGHUP necessary? - # - # It's often suggested that the SIGHUP signal should be ignored before - # the second fork to avoid premature termination of the process. The - # reason is that when the first child terminates, all processes, e.g. - # the second child, in the orphaned group will be sent a SIGHUP. - # - # "However, as part of the session management system, there are exactly - # two cases where SIGHUP is sent on the death of a process: - # - # 1) When the process that dies is the session leader of a session that - # is attached to a terminal device, SIGHUP is sent to all processes - # in the foreground process group of that terminal device. - # 2) When the death of a process causes a process group to become - # orphaned, and one or more processes in the orphaned group are - # stopped, then SIGHUP and SIGCONT are sent to all members of the - # orphaned group." [2] - # - # The first case can be ignored since the child is guaranteed not to have - # a controlling terminal. The second case isn't so easy to dismiss. - # The process group is orphaned when the first child terminates and - # POSIX.1 requires that every STOPPED process in an orphaned process - # group be sent a SIGHUP signal followed by a SIGCONT signal. Since the - # second child is not STOPPED though, we can safely forego ignoring the - # SIGHUP signal. In any case, there are no ill-effects if it is ignored. - # - # import signal # Set handlers for asynchronous events. - # signal.signal(signal.SIGHUP, signal.SIG_IGN) - try: # Fork a second child and exit immediately to prevent zombies. This # causes the second child process to be orphaned, making the init @@ -108,86 +44,39 @@ def createDaemon(function, logfile): except OSError as e: raise Exception("%s [%d]" % (e.strerror, e.errno)) - if (pid == 0): # The second child. - # We probably don't want the file mode creation mask inherited from - # the parent, so we give the child complete control over permissions. - if UMASK is not None: - os.umask(UMASK) - else: + if (pid != 0): # Parent (the first child) of the second child. + # exit() or _exit()? + # _exit is like exit(), but it doesn't call any functions registered + # with atexit (and on_exit) or any registered signal handlers. It also + # closes any open file descriptors. Using exit() may cause all stdio + # streams to be flushed twice and any temporary files may be unexpectedly + # removed. It's therefore recommended that child branches of a fork() + # and the parent branch(es) of a daemon use _exit(). os._exit(0) else: - # exit() or _exit()? - # _exit is like exit(), but it doesn't call any functions registered - # with atexit (and on_exit) or any registered signal handlers. It also - # closes any open file descriptors. Using exit() may cause all stdio - # streams to be flushed twice and any temporary files may be unexpectedly - # removed. It's therefore recommended that child branches of a fork() - # and the parent branch(es) of a daemon use _exit(). + os.waitpid(pid, 0) return - # Close all open file descriptors. This prevents the child from keeping - # open any file descriptors inherited from the parent. There is a variety - # of methods to accomplish this task. Three are listed below. - # - # Try the system configuration variable, SC_OPEN_MAX, to obtain the maximum - # number of open file descriptors to close. If it doesn't exist, use - # the default value (configurable). - # - # try: - # maxfd = os.sysconf("SC_OPEN_MAX") - # except (AttributeError, ValueError): - # maxfd = MAXFD - # - # OR - # - # if (os.sysconf_names.has_key("SC_OPEN_MAX")): - # maxfd = os.sysconf("SC_OPEN_MAX") - # else: - # maxfd = MAXFD - # - # OR - # - # Use the getrlimit method to retrieve the maximum file descriptor number - # that can be opened by this process. If there is no limit on the - # resource, use the default value. - # - import resource # Resource usage information. - maxfd = resource.getrlimit(resource.RLIMIT_NOFILE)[1] - if (maxfd == resource.RLIM_INFINITY): - maxfd = MAXFD - - # Iterate through and close all file descriptors. -# for fd in range(0, maxfd): -# try: -# os.close(fd) -# except OSError: # ERROR, fd wasn't open to begin with (ignored) -# pass - - # Redirect the standard I/O file descriptors to the specified file. Since - # the daemon has no controlling terminal, most daemons redirect stdin, - # stdout, and stderr to /dev/null. This is done to prevent side-effects - # from reads and writes to the standard I/O file descriptors. - - # This call to open is guaranteed to return the lowest file descriptor, - # which will be 0 (stdin), since it was closed above. -# os.open(REDIRECT_TO, os.O_RDWR) # standard input (0) - - # Duplicate standard input to standard output and standard error. -# os.dup2(0, 1) # standard output (1) -# os.dup2(0, 2) # standard error (2) - + # The second child. + # Replace standard fds with our own si = open('/dev/null', 'r') - so = open(logfile, 'w') - se = so - - - # Replace those fds with our own os.dup2(si.fileno(), sys.stdin.fileno()) - os.dup2(so.fileno(), sys.stdout.fileno()) - os.dup2(se.fileno(), sys.stderr.fileno()) - function() + try: + so = open(logfile, 'a+') + se = so + os.dup2(so.fileno(), sys.stdout.fileno()) + os.dup2(se.fileno(), sys.stderr.fileno()) + except io.UnsupportedOperation: + sys.stdout = open(logfile, 'a+') + sys.stderr = sys.stdout - os._exit(0) + try: + function() + except Exception as e: + traceback.print_exc() + finally: + bb.event.print_ui_queue() + os._exit(0) |
