07-18-2008
I would build in a logic context so that you can be sure. For example, SIGHUP is a non-zero vector when a process is started. It is good practice to null the vector after one's fork/exec (in the child, of course), obviously to avoid the humiliation of having one's nice daemon code quit when the starter-upper terminates. So, then, your test could be "is my SIGHUP vector NULL?" and process accordingly. Use your OS facilities to good purpose, and let them help identify your context, too.
Last edited by fsahog; 07-18-2008 at 09:25 PM..
Reason: To make it better
10 More Discussions You Might Find Interesting
1. Programming
Hi,
I have to write a daemon process, which performs certain operations in the background.
Now since it performs operations in the background, it should not display anything to the standard output.
The problem is that it still displays, text on standard output.
Can anyone tell me (it is... (2 Replies)
Discussion started by: s_chordia
2 Replies
2. Programming
This is gonna seem really silly to almost evryone here - but I need to know :
what is a daemon process?
Thanks (6 Replies)
Discussion started by: Kanu77
6 Replies
3. UNIX for Advanced & Expert Users
My daemon process is the child of init and init has the responsibility to remove it, once it turns zombie. But I want to ask why the daemon process which is child of init turns zombie in the first place. What measures I have to take to avoid this?
rish (1 Reply)
Discussion started by: rish2005
1 Replies
4. Linux
how i will write the daemon process,if any body have sample daemon process send me. (1 Reply)
Discussion started by: suresh_rupineni
1 Replies
5. Shell Programming and Scripting
Hello,
I need to run a command on remote Linux using the ssh command from my local machine. I am able to execute the command on remote machine using ssh but it's behaving strangely.
The command is supposed to start a daemon process on remote linux box and the control should return back to me... (5 Replies)
Discussion started by: nitinshukla
5 Replies
6. UNIX for Dummies Questions & Answers
Hello,
I am new to this forum and this is my first post here...
I have never worked on either Pro*C or Multithreading..Now, i have to write a Pro*C, Multithreading daemon process.. I dont know where to start.. Can anybody help me with examples?
1. need to write a Pro*C multithreading... (0 Replies)
Discussion started by: kachiraju
0 Replies
7. Shell Programming and Scripting
Dear Unix Gurus,
Plz provide major diff between background process and daemon process.
Is it control available for daemon process?. (3 Replies)
Discussion started by: kkl
3 Replies
8. Shell Programming and Scripting
Hi,
HI ,
I have a simple script that moves files from one folder to another folder, I have already done the open-ssh server settings and the script is working fine and is able to transfer the files from one folder to another but right now I myself execute this script by using my creditianls to... (3 Replies)
Discussion started by: nks342
3 Replies
9. UNIX for Dummies Questions & Answers
Hi,
When process listing, I came across a process running as user daemon.
daemon 23576 23574 0 07:32:04 ? 0:07 oracle (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))
root 27526 27444 1 07:38:43 ttyp5 0:00 grep 23574
why a process runs as user daemon, when it should be... (3 Replies)
Discussion started by: wilsonee
3 Replies
10. Programming
I wish to make a process run in the background, but only one instance of it, and not many,
so when the program is loaded, it has to check whether another instance of the same
program is running and if so to exit. How do I do this ? (4 Replies)
Discussion started by: sundaresh
4 Replies
LEARN ABOUT FREEBSD
daemon
DAEMON(8) BSD System Manager's Manual DAEMON(8)
NAME
daemon -- run detached from the controlling terminal
SYNOPSIS
daemon [-cfr] [-p child_pidfile] [-P supervisor_pidfile] [-u user] command arguments ...
DESCRIPTION
The daemon utility detaches itself from the controlling terminal and executes the program specified by its arguments. Privileges may be low-
ered to the specified user.
The options are as follows:
-c Change the current working directory to the root (``/'').
-f Redirect standard input, standard output and standard error to /dev/null.
-p child_pidfile
Write the ID of the created process into the child_pidfile using the pidfile(3) functionality. The program is executed in a spawned
child process while the daemon waits until it terminates to keep the child_pidfile locked and removes it after the process exits.
The child_pidfile owner is the user who runs the daemon regardless of whether the -u option is used or not.
-P supervisor_pidfile
Write the ID of the daemon process into the supervisor_pidfile using the pidfile(3) functionality. The program is executed in a
spawned child process while the daemon waits until it terminates to keep the supervisor_pidfile locked and removes it after the
process exits. The supervisor_pidfile owner is the user who runs the daemon regardless of whether the -u option is used or not.
-r Supervise and restart the program if it has been terminated.
-u user
Login name of the user to execute the program under. Requires adequate superuser privileges.
If the -p, -P or -r option is specified the program is executed in a spawned child process. The daemon waits until it terminates to keep the
pid file(s) locked and removes them after the process exits or restarts the program. In this case if the monitoring daemon receives software
termination signal (SIGTERM) it forwards it to the spawned process. Normally it will cause the child to exit, remove the pidfile(s) and then
terminate.
The -P option is useful combined with the -r option as supervisor_pidfile contains the ID of the supervisor not the child. This is especially
important if you use -r in an rc script as the -p option will give you the child's ID to signal when you attempt to stop the service, causing
daemon to restart the child.
EXIT STATUS
The daemon utility exits 1 if an error is returned by the daemon(3) library routine, 2 if child_pidfile or supervisor_pidfile is requested,
but cannot be opened, 3 if process is already running (pidfile exists and is locked), otherwise 0.
DIAGNOSTICS
If the command cannot be executed, an error message is displayed on standard error unless the -f flag is specified.
SEE ALSO
setregid(2), setreuid(2), daemon(3), exec(3), pidfile(3), termios(4), tty(4)
HISTORY
The daemon utility first appeared in FreeBSD 4.7.
BSD
September 13, 2013 BSD