Deleting ALL message queue


 
Thread Tools Search this Thread
Top Forums Programming Deleting ALL message queue
# 1  
Old 06-01-2005
Question Deleting ALL message queue

hi all,
I'm working on this problem for 2 days. Can somebody tell me that how to delete all message queues from the system ?
Since "ipcs -q" gives the list of all existing message queue, then there must be a system call and data stucture where from I can fetch the data about all existing message queues.
I just want to know, how i can delete ALL message queues from the system thruogh a C program.
# 2  
Old 06-01-2005
The best way to get a systemwide list of the message queues is via popen("ipcs -q", "r") but that's not what you want to hear. Programs like ps, sar, vmstat, etc cannot be portably written. You must not realize this, or you would have broken with tradition and mentioned your specific OS as you posed the question.

With standard System V release 4, you would run namelist(3) on the kernel to obtain the address of msginfo. You would then open(2) /dev/kmem, lseek(2), to that address, and read(2) the data structure. You would know the the layout of the data structure because it is somewhere in /usr/include/sys.

This exact sequence of operations is not likely to work on modern OS's, even those based on System V, release 4. Some vendors do not want to support stuff like this and worked hard to render it impossible with a little bit of success. Others have fiddled greatly with the OS and different techniques must now be employed. In general, you need to obtain the source code for your OS, view ipcs.c and copy what it does.
# 3  
Old 06-02-2005
Sir,thank you for your valuable suggestion. I'll surely try this thing out and tell you the results.
You wrote that i need to obtain the source code for my OS in order to know how "ipcs.c" works. Can you tell me how i can get the source code of my OS?? i'm using Red Hat 9.
One more request, can i add you in my buddy list??
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Ubuntu

Message Queue in Linux

Hello How can I see the created message queues in the system? (4 Replies)
Discussion started by: xyzt
4 Replies

2. Programming

UNIX Message Queue

Hello !!!!! I have a simple question but i can't find the answer anywhere hope to meet it here. Why it is a bad idea to pass pointers through message queues ? Most structs i see all of their char types are arrays... Is it becase having pointers means we could possibily send wrong bytes ? For... (2 Replies)
Discussion started by: qlyine
2 Replies

3. Programming

Message Queue Problem

Hi all, I need help about message queues, i have a server-client program that communicates each other via msg queue, firstly server opens its msg queue and waits for msg then client opens server msg queue and its own msg queue(for receiving msg from server,clients sends msg to server msg... (7 Replies)
Discussion started by: SaTYR
7 Replies

4. Programming

How to limit max no of message in a posix message queue

Hii can anyone pls tell how to limit the max no of message in a posix message queue. I have made changes in proc/sys/fs/mqueue/msg_max But still whenever i try to read the value of max. message in the queue using attr.mq_curmsgs (where struct mq_attr attr) its giving the default value as 10.... (0 Replies)
Discussion started by: mohit3884
0 Replies

5. Programming

message queue

Hello, i need to write a message queue "chat server", that should work only localy. Can anyone please help me with some ideas and peshaps code. I'm studying the UNIX IPC mechanisms right now. So far, i understand how it works but i still cannot get an idea how to write a chat programm... ... (2 Replies)
Discussion started by: etenv
2 Replies

6. Programming

Message Queue with fork() help

hi all... ive been trying this program where i spawn 4 threads... and i am trying to use message queue to send msgs from 3 of the threads to the parent thread... but it doent seem to be working... ive almost pulled out my hair tryin to fix the prob :confused: another wierd thing... (1 Reply)
Discussion started by: strider
1 Replies

7. IP Networking

message queue problem

I am sending and retriving the message to the queue the problem is after retrieving the message can i see what is there in my message queue. (actually in my application i am encountring some garbage value) so i want to retieve this garbage value and also want to know its size how... (0 Replies)
Discussion started by: ramneek
0 Replies

8. Programming

Message Queue Problem Again..

Is there any way one can delete , say , a particular message from a message queue on system V? (2 Replies)
Discussion started by: satansfury
2 Replies

9. Programming

a message queue question..

Hi there: Thanks first. When I use a message queue amony severl processes, will I have to synchronize the queue? I don't think I would have to because a message queue is implemented in a link listed. Correct me If I am wrong... (0 Replies)
Discussion started by: yanhu
0 Replies

10. UNIX for Advanced & Expert Users

Unix message Queue

Hi, I am working closly with unix message queues i have encountered the following - after creating the Q and start working with it (pushing & pulling) i receive the following stange parameters on the q's - STIME=no_entry Qnum=0 CBYTES=4140 when this happens, the Q is disabled (meaning i... (3 Replies)
Discussion started by: kel
3 Replies
Login or Register to Ask a Question