| import os |
| import sys |
| |
| if os.name == 'posix': |
| def become_daemon(our_home_dir='.', out_log='/dev/null', |
| err_log='/dev/null', umask=022): |
| "Robustly turn into a UNIX daemon, running in our_home_dir." |
| # First fork |
| try: |
| if os.fork() > 0: |
| sys.exit(0) # kill off parent |
| except OSError, e: |
| sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror)) |
| sys.exit(1) |
| os.setsid() |
| os.chdir(our_home_dir) |
| os.umask(umask) |
| |
| # Second fork |
| try: |
| if os.fork() > 0: |
| os._exit(0) |
| except OSError, e: |
| sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror)) |
| os._exit(1) |
| |
| si = open('/dev/null', 'r') |
| so = open(out_log, 'a+', 0) |
| se = open(err_log, 'a+', 0) |
| os.dup2(si.fileno(), sys.stdin.fileno()) |
| os.dup2(so.fileno(), sys.stdout.fileno()) |
| os.dup2(se.fileno(), sys.stderr.fileno()) |
| # Set custom file descriptors so that they get proper buffering. |
| sys.stdout, sys.stderr = so, se |
| else: |
| def become_daemon(our_home_dir='.', out_log=None, err_log=None, umask=022): |
| """ |
| If we're not running under a POSIX system, just simulate the daemon |
| mode by doing redirections and directory changing. |
| """ |
| os.chdir(our_home_dir) |
| os.umask(umask) |
| sys.stdin.close() |
| sys.stdout.close() |
| sys.stderr.close() |
| if err_log: |
| sys.stderr = open(err_log, 'a', 0) |
| else: |
| sys.stderr = NullDevice() |
| if out_log: |
| sys.stdout = open(out_log, 'a', 0) |
| else: |
| sys.stdout = NullDevice() |
| |
| class NullDevice: |
| "A writeable object that writes to nowhere -- like /dev/null." |
| def write(self, s): |
| pass |
