Sponsored Content
Top Forums Programming How to implement SIGKILL and SIGTERM and print a message? Post 302144795 by porter on Friday 9th of November 2007 08:01:14 PM
Old 11-09-2007
1. Both sigaction and signal install signal handlers,

(a) don't use both in the same program,
(b) sigaction is the posix one, use that.
(c) With sigaction you don't need to reinstall the signal handler.

2. atexit installs another callback function, so when the program exits politely, through a call to exit you code will get called so you can tidy up.

3. only set flags in the signal handlers, don't do 'work'.

4. you have done sigfillset but done nothing with the sigset_t, you need to call sigprocmask to block or unblock those signals.

5. to ignore a signal, you can

(a) either use SIG_IGN as the callback
(b) or simply block it so it is never delivered to your program.
(c) or get it to call an empty signal handler function

6. compile with maximum warnings, if you are using gcc use "-Wall -Werror", that would have caught your "atexit".

7. And as mentioned, you can't catch SIGKILL, the kernel will just evaporate your process.
 

10 More Discussions You Might Find Interesting

1. Programming

signals - SIGTERM

Hi all, I need some urgent help. we are using Dynix/ptx V4.5 on i386, have several processes and instances are running on the box round the clock.we increased the processes recently. We have coded to handle the signals in our programs. Recently, we noticed most of our processes are... (2 Replies)
Discussion started by: reddyb
2 Replies

2. Shell Programming and Scripting

Why SIGKILL will occur?

Hi Gurus, I am executing my Datastage jobs on UNIX operating System. While running the jobs i am getting the following error: main_program: Unexpected termination by Unix signal 9(SIGKILL) Can any one please let me know what are the possible situations where this SIGKILL will arrise? ... (9 Replies)
Discussion started by: choppas
9 Replies

3. Solaris

To print Coloured Prelogin Message on SOLARIS--9................

Hiiii..... Every one...... I am using /etc/issue file to display Pre-login Message on my system, installed with SOLARIS-9. I am getting this Message in White fonts having Black background ( Colour of the Screen)..... So, is there ... (2 Replies)
Discussion started by: prashantshukla
2 Replies

4. Shell Programming and Scripting

Error while trying to print message

Hi all Geting this error while trying to print message as : ./logfunc: print: bad file unit number heres what i m trying to do : log_date="$(date '+%d/%m/%Y %H:%M:%S')" log_type="Message" print "${log_date}: ${log_type}" print -u3 "${log_date}: ${log_type}" this error is due to... (3 Replies)
Discussion started by: Navatha
3 Replies

5. Shell Programming and Scripting

Print a message at specific line on prompt

Hi Friends, I am using HP-UNIX(ksh). I want to print a message at specific line on the prompt screen. For Example: for num in 1 10 3 145 do echo $num // need to print this on the same line for each number sleep 2 done Actual Output: ========== 1 10 3 145 Expected Output:... (5 Replies)
Discussion started by: Niroj
5 Replies

6. Solaris

SIGQUIT and SIGKILL message

Dear All, I have machine with SunOS 5.10 Generic_138888-01 sun4v sparc SUNW,SPARC-Enterprise-T5120. Yesterday there is something at dmesg command : May 25 18:09:02 cacao_launcher: Timeout occured on heartbeat channel, cleanup engaged May 25 18:09:07 cacao_launcher: watchdog : warning,... (0 Replies)
Discussion started by: mbah_jiman
0 Replies

7. Shell Programming and Scripting

How to detect SIGTERM,SIGKILL signal in UNIX

Dear All We have JBOSS server running on Linux we need to track Graceful Shutdown(SIGTERM) and Forceful Shutdown(SIGKILL) timestamp and write it into one file, I am new to UNIX Signal processing if is it possible how to detect it? We generally do $kill PID For Graceful... (5 Replies)
Discussion started by: mnmonu
5 Replies

8. Shell Programming and Scripting

SIGSTOP and SIGKILL

Which is sent to a terminal when it closes? SIGKILL? Reason I ask is I have a script I want to run in the background, but want it to run even if the terminal window is closed. Or, I'd like it to background itself if the terminal is closed but not if its running in an open window. I will learn how... (5 Replies)
Discussion started by: DC Slick
5 Replies

9. UNIX for Advanced & Expert Users

Print message while using sqlplus

I want to connect to oracle database from solaris... After that i will drop and create a no.of tables.One of the table example is as below. sqlplus -s usrname/password@dbname << SQL >> $logfile 2>&1 echo " dropping the table1" | tee logfile DROP TABLE Table1 echo "creating the table1" |... (1 Reply)
Discussion started by: millan
1 Replies

10. Shell Programming and Scripting

Script to check the string in a file and print an attribute in the message

Hi, I am new to shell scripting and got a task to complete. Task is : we have a log file where in i need to traverse through the whole file to check the string "Person Type missing in message" and after that i need to get EMPLID=xxxxxx from the file and print details in a different file. ... (1 Reply)
Discussion started by: suren424
1 Replies
RAISE_DEFAULT_SIGNAL(3) 				   BSD Library Functions Manual 				   RAISE_DEFAULT_SIGNAL(3)

NAME
raise_default_signal -- raise the default signal handler LIBRARY
System Utilities Library (libutil, -lutil) SYNOPSIS
#include <util.h> int raise_default_signal(int sig); DESCRIPTION
The raise_default_signal() function raises the default signal handler for the signal sig. This function may be used by a user-defined signal handler router to ensure that a parent process receives the correct notification of a process termination by a signal. This can be used to avoid a common programming mistake when terminating a process from a custom SIGINT or SIGQUIT signal handler. The operations performed are: 1. Block all signals, using sigprocmask(2). 2. Set the signal handler for signal sig to the default signal handler (SIG_DFL). 3. raise(3) signal sig. 4. Unblock signal sig to deliver it. 5. Restore the original signal mask and handler, even if there was a failure. See signal(7) for a table of signals and default actions. The raise_default_signal() function should be async-signal-safe. RETURN VALUES
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and the global variable errno is set to indicate the error. ERRORS
The raise_default_signal() function may fail and set errno for any of the errors specified for the functions sigemptyset(3), sigfillset(3), sigaddset(3), sigprocmask(2), sigaction(2), or raise(3). SEE ALSO
sigaction(2), sigprocmask(2), raise(3), signal(7) HISTORY
The raise_default_signal() function first appeared in NetBSD 5.0. BSD
September 25, 2007 BSD
All times are GMT -4. The time now is 09:09 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy