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 ?
If your system supports the semget() and semop() calls that are included in one of the optional features in the POSIX standards, you can use semget() to get access to a semaphore with a key that is known to your daemon. After getting the semaphore ID you can use semop() with an array of two operations at the start of your program. These operations are:
If the semop() call fails with EAGAIN, another daemon is already running and owns the semaphore. If the semop() call succeeds, this daemon owns the semaphore until it terminates. (It doesn't matter if this daemon terminates due to receipt of an uncaught signal or terminates normally by calling exit, the SEM_UNDO flag will release ownership of the semaphore when the daemon terminates.)
If you don't have access to a similar set of semaphore operations, a common approach is to atomically create (with open flags O_CREAT | O_EXCL) a lock file and write the PID of the daemon that created the lock into the lock file. The daemon should then remove the lock file before it exits. (If the daemon is killed before it can remove the lock file, another daemon won't be able to start until you manually remove the lock file.)
This User Gave Thanks to Don Cragun For This Post:
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)
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)
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)
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)
I have a scenario where I need to find if a process is a daemon process or not. This check needs to be done from within the process. I know there are no direct API's to do so. I have explored these options.
1. ctermid() - this can be unsuccessful as per the man pages
2. int devtty; if ((devtty... (7 Replies)
Hi All,
I am facing problem in launching a application with the help of a daemon process. Actually the application is based on command line that reads various commands for controlling the application from the console and accordingly executes those commands. The application always interact with... (3 Replies)
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
LEARN ABOUT XFREE86
asadmin-restart-instance
asadmin-restart-instance(1AS) User Commands asadmin-restart-instance(1AS)NAME
asadmin-restart-instance, restart-instance - restarts the specified server instance and all the services associated with it
SYNOPSIS
restart-instance [--user admin_user] [--password admin_password] [--host localhost] [--port 4848] [--local=false] [--domain domain_name]
[--passwordfile filename] [--secure|-s]instance_name
Use the restart-instance to restart the instance with the instance name specified. The restart-instance command can be run both locally and
remotely. To restart remotely, the administration server must be running on the hostname and port number specified. The user authenticates
using the password identified for the administration server. Additionally, the instance must already exist within the domain served by the
administration server, and the instance must be running. The restart-instance command is not supported on Windows.
OPTIONS --user administrative user associated for the instance.
--password administrative password corresponding to the administrative user.
--host host name of the machine hosting the administrative instance.
--port administrative port number associated with the administrative host.
--local determines if the command should delegate the request to administrative instance or run locally.
--domain name of the domain.
--passwordfile file containing passwords appropriate for the command (e.g., administrative instance).
--secure if true, uses SSL/TLS to communicate with the administrative instance.
OPERANDS
instance_name name of the instance to be restarted.
Example 1: Using restart-instance in local mode
asadmin> restart-instance --local --domain domain1 server1
Instance server1 started
Where: server1 is the name of the instance restarted on the domain1 domain.
Example 2: Using restart-instance in remote mode
asadmin> restart-instance --user admin --password adminadmin --host bluestar --port 4848 server1
Instance server1 started
Where: server1 is the name of the instance restarted. The restarted instance is associated with the user, password, host, and port number
specified.
EXIT STATUS
0 command executed successfully
1 error in executing the command
INTERFACE EQUIVALENT
Server Instance page
asadmin-delete-instance(1AS), asadmin-start-instance(1AS), asadmin-create-instance(1AS), asadmin-stop-instance(1AS), asadmin-start-
appserv(1AS), asadmin-stop-appserv(1AS), asadmin-start-domain(1AS), asadmin-stop-domain(1AS)J2EE 1.4 SDK March 2004 asadmin-restart-instance(1AS)