On 12/11/2012 08:47 AM, andrea crotti wrote:
Yes I wanted to avoid to do something too complex, anyway I'll just
comment it well and add a link to the original code..
But this is now failing to me:
def daemonize(stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
# Perform first fork.
try:
pid = os.fork()
if pid > 0:
sys.exit(0) # Exit first parent.
except OSError as e:
sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno, e.strerror))
sys.exit(1)
# Decouple from parent environment.
os.chdir("/")
os.umask(0)
os.setsid()
# Perform second fork.
try:
pid = os.fork()
if pid > 0:
sys.exit(0) # Exit second parent.
except OSError, e:
sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno, e.strerror))
sys.exit(1)
# The process is now daemonized, redirect standard file descriptors.
sys.stdout.flush()
sys.stderr.flush()
si = file(stdin, 'r')
so = file(stdout, 'a+')
se = file(stderr, 'a+', 0)
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
if __name__ == '__main__':
daemonize(stdout='sample_file', stderr='sample')
print("hello world, now should be the child!")
[andrea@andreacrotti experiments]$ python2 daemon.py
Traceback (most recent call last):
File "daemon.py", line 49, in <module>
daemonize(stdout='sample_file', stderr='sample')
File "daemon.py", line 41, in daemonize
so = file(stdout, 'a+')
IOError: [Errno 13] Permission denied: 'sample_file'
The parent process can write to that file easily, but the child can't,
why is it working for you and not for me though?
(Running this on Linux with a non-root user)
In the time when you fork the proccess you can't use relative path, is
dangerous. You need to use absolute path's like this.
import os, sys
def daemonize(stdin='/dev/null', stdout='/dev/null', stderr='/dev/null'):
# Perform first fork.
try:
pid = os.fork()
if pid > 0:
sys.exit(0) # Exit first parent.
except OSError as e:
sys.stderr.write("fork #1 failed: (%d) %s\n" % (e.errno,
e.strerror))
sys.exit(1)
# Decouple from parent environment.
os.chdir("/")
os.umask(0)
os.setsid()
# Perform second fork.
try:
pid = os.fork()
if pid > 0:
sys.exit(0) # Exit second parent.
except OSError, e:
sys.stderr.write("fork #2 failed: (%d) %s\n" % (e.errno,
e.strerror))
sys.exit(1)
# The process is now daemonized, redirect standard file descriptors.
sys.stdout.flush()
sys.stderr.flush()
si = file(stdin, 'r')
so = file(stdout, 'a+')
se = file(stderr, 'a+', 0)
os.dup2(si.fileno(), sys.stdin.fileno())
os.dup2(so.fileno(), sys.stdout.fileno())
os.dup2(se.fileno(), sys.stderr.fileno())
if __name__ == '__main__':
daemonize(stdout='/tmp/sample_file.log', stderr='/tmp/sample.log')
print("hello world, now should be the child!")
--
http://mail.python.org/mailman/listinfo/python-list
