Inter Process Communication usually refers to kernel services that allow processes on the same machine to communicate with each other.

learn more… | top users | synonyms

1
vote
1answer
20 views

where does go data written to file descriptor that was never opened

I have output captured by following command: $ strace -f -e trace=process,socketpair,open,close,dup,dup2,read,write -o rsync.log rsync -avcz --progress src/ dst/ it is a bit long so I've uploaded ...
1
vote
0answers
17 views

strace for troubleshooting inter process communication

I have output captured by following command: strace -f -e trace=process,socketpair,open,close,dup,dup2,read,write -o rsync.log rsync -avcz --progress src/ dst/ it is a bit long so I've uploaded it ...
-3
votes
1answer
49 views

How to do inter process communication using single bidirectional pipe in linux?

How do 2 processes communicate by using single bidirectional pipe, such that both the ends of the pipe could read and write. I have an assignment to do, kindly help me with this.
2
votes
2answers
47 views

What core kernel-level IPC mechanisms exist in Linux?

Off the top of my head, I know there are: pipes FIFO files / named pipes message queues shared memory semaphores signals Is that the complete list? Doing a bit of research, I think it may be, but ...
1
vote
0answers
27 views

Why are there no LSM hooks in the POSIX IPC APIs?

As I understand it, the Linux Security Module (LSM) framework has many hooks which are callbacks for security modules to register functions performing additional security checks before security-...
10
votes
3answers
651 views

How to implement “generators” like $RANDOM?

The special variable $RANDOM has a new value every time it's accessed. In this respect, it is reminiscent of the "generator" objects found in some languages. Is there a way to implement something ...
-1
votes
1answer
100 views

are named pipes (mkfifo) the predecessor of RabbitMQ? [closed]

Is RabbitMQ, for inter process communication, like pipes and named pipes? How does RabbitMQ compare to named pipes? Except distributed systems. (RabbitMQ, for those who haven't encountered it, is an ...
0
votes
1answer
31 views

Server port doenst go back to listen and is in closed_wait state , because of starting an daemon application from client

Below is the basic client and server code . While iam trying to start an appliaction(which has to keep running in the machine once we send a msg to server) during connect call. using system(/bin/...
2
votes
1answer
212 views

Differences between Unix Domain Sockets and Network Sockets?

Am I right that When two processes communicate by network sockets, each process create a socket (each socket belongs to one process), and the processes communicate by their sockets. When two ...
0
votes
0answers
49 views

What kinds of IPC are used in ssh port forwarding?

SSH local forwarding is specified by: -L [bind_address:]port:host:hostport on the local host, a process called P1 attaches to port, so that P1 and the ssh client SC can communicate. What type of ...
-1
votes
1answer
289 views

Communicating derived C++ types through a named pipe impossible? [closed]

I found that communicating a derived C++ type such as an opencv Mat or other derived types do go through the pipe if I send the derived type as a reference through a pipe: //Measurement FIFO ...
1
vote
1answer
48 views

Which process group does my program belong to when started from bash?

If I run a program from bash, then does my program belong to the same process group as the shell, or does it belong to a new process group? As I am making a shell in C, I need to handle the SIGINT ...
-1
votes
1answer
107 views

Why does grep goes into blocking stage? [closed]

I am making a test My task will be one child pipelining the output to the input of another another child. I am using ps -ef as the first command(by using execlp()) and grep root as the second command(...
1
vote
1answer
189 views

Deadlock on read/wait [closed]

My process deadlocks. master looks like this: p=Popen(cmd, stdin=PIPE, stdout=PIPE) for ....: # a few million p.stdin.write(...) p.stdin.close() out = p.stdout.read() p.stdout.close() exitcode = ...
0
votes
1answer
186 views

Why signal function is not able to call my signal Handler? [closed]

Here I have written a signal handler function named as handler Correspondingly this handler is registered to kernel using the signal function that will be invoked when SIGCHLD signal is generated by ...
2
votes
1answer
71 views

ipcs(1) POSIX equivalent to System V

I know that with ipcs(1) command, one can monitor System V message queues, shared memory and semaphores, but how do I monitor POSIX message queues, shared memory and semaphores. For POSIX message ...
1
vote
1answer
254 views

Linux - check processes using IPC channels

This is related to my previous question. Given that I can find the statistics of IPC channels in my Linux system (e.g. sys V IPC), how can I find which processes are using certain IPC channel (...
2
votes
1answer
120 views

Linux - check IPC stats

What is the best way of checking current status of different types of IPC in Linux (including uids) ? I want to inspect named pipes, half duplex pipes, unix domain sockets, signals. I know for sys V ...
10
votes
4answers
2k views

How to list all object paths under a dbus service?

This is a follow-up question to A list of available DBus services. The following python code will list all available DBus services. import dbus for service in dbus.SystemBus().list_names(): ...
2
votes
0answers
229 views

UNIX sockets vs AF_NETLINK vs Kdbus vs Binder

What are essential differences between those IPCs? Which are main use cases? Is there some consolidated comparison table between them somewhere? Something like: Protocol: AF_UNIX | ...
2
votes
0answers
65 views

Reasons for IPC control in Linux [closed]

Linux OS has several IPC mechanisms like named pipes, sys V, d-bus etc. Each of these mechanisms always has senders and receivers of IPC; each mechanism uses some way to control IPC between senders ...
0
votes
1answer
413 views

Porting Binder IPC to Linux

Android provides a device driver based IPC mechanism called Binder. I see it as one of the staging drivers in Linux. Although I can have a linux kernel running with this device driver, if I want to ...
2
votes
0answers
72 views

process waiting for a semaphore

If I have a process that is in sleep state and i can see in ps' column WCHAN that is waiting to obtain a semaphore, is there any way to find the adress of that semaphore?
1
vote
0answers
83 views

process blocked in msgrcv

I have a process that is blocked in msgrcv as shown by ps -eo pid,tid,wchan. Is there any way to find the PID of the process that my process is expecting to receive a message from? The communication ...
2
votes
1answer
257 views

Why does the clock need a shared memory segment?

This is a combination of programming and Linux question but I think it suits better here. I am writing an application that works with ipcs (shared memory segments) and after each running I am ...
2
votes
1answer
500 views

Advantages of using named pipes and sockets rather than temporary files

I have two cooperating programs. One program just writes its output to a file and the other one then reads from the file and spits the data out for the front end to work with. I have been reading ...
0
votes
0answers
202 views

Stopping syslogd also closes /dev/log UNIX domain socket

I am working on a project and from some testing I found out that stopping syslogd daemon also closes /dev/log socket. Is there some other way so that even if syslogd is down, /dev/log socket still ...
1
vote
1answer
49 views

What are the files in /tmp that start with “qipc”?

There are empty files like this in my /tmp directory: qipc_sharedmemory_soliddiskinfomemac5ffa537fd8798875c98e190df289da7e047c05 ...
1
vote
0answers
1k views

Can a process running in a linux container communicate with another process running on the host OS via IPC?

I have 2 processes A and B. Currently, both A and B are running on the same OS (RHEL6.2) and the processes can intercommunicate via TCP sockets. My objective is to run process B in a Linux Container ...
7
votes
3answers
611 views

`/proc/$PID/cwd` : is there a POSIX equivalent?

Linux has a /proc directory and file‑system, which as far as I can tell, is not part of POSIX. In each /proc/$PID subdirectories, is a symbolic link, cwd, pointing to the actual working directory of ...
2
votes
1answer
292 views

Whats the sense of dbus objects?

Despite reading through tons of Dbus - tutorials, I still struggle to understand the whole concept. In my opinion this was one of the best explanations so far: http://telepathy.freedesktop.org/doc/...
1
vote
0answers
271 views

Find and close/unlink message queues in the system

I have a SLES-11 machine on which I am not the root where I am building software code that makes extensive use of message queues. Due to some bugs, Now have an error: mq_open: Too many open files I ...
0
votes
1answer
2k views

Which IPC is supported in Ubuntu 12.04: POSIX or System V

How do I know which type of IPC is supported in Ubuntu 12.04: System V or POSIX Is there any command to get this ?
1
vote
1answer
1k views

Creating a terminal device for interprocess communication

I'd like to know how to create a terminal device to simulate a piece of hardware connected through a serial port. Basically, tty device with a certain baud rate that can be read from and written to ...
13
votes
4answers
12k views

Are FIFO, pipe & Unix domain socket the same thing in Linux kernel?

I heard that FIFOs are named pipes. And they have exactly the same semantics. On the other hand, I think Unix domain socket is quite similar to pipe (although I've never made use of it). So I wonder ...
2
votes
0answers
222 views

So the design of client-server separation is not the bottleneck of X Window?

In the answer of this, it mentioned: People also hear that X uses the "network" and think this is going to be a performance bottleneck. "Network" here means local UNIX domain socket, which has ...
4
votes
3answers
15k views

linux command to check POSIX message queue

We can check the details of system V message queue with the help of ipcscommand. Is there any command to check POSIX message queue in Linux?
4
votes
3answers
2k views

Does one end of a pipe have both read and write fd?

As far as I understood one end of a pipe has both read and write fd's and the other end also has read and write fd's. Thats why when we are writing using fd[1], we are closing the read end e.g. fd[0]...
3
votes
3answers
4k views

What after exec() in ls command. Is the parent process printing the output to the console or the child?

I have a simple doubt on execution of the command ls. As per my understanding from the research I have done on the internet, I understood the below points. When we type ls command shell interprets ...
0
votes
2answers
4k views

Sending SIGUSR1 to parent

When I do a kill -SIGUSR1 $PPID I get kill: (1) - Operation not permitted . How can I overcome this?
3
votes
0answers
245 views

Why message queues are not being used for any system level applications in Ubuntu OS?

In my Linux machine, when i run 'ipcs' command, I have the below information listed srinivas@srinivas-G41MT-S2:~$ ipcs -a ------ Shared Memory Segments -------- key shmid owner ...
8
votes
2answers
3k views

Why there are only two user defined signals?

In the list of signals defined in a linux system, there are two signals stated as User Defined signals (SIGUSR1 and SIGUSR2). Other signals will be raised or caught in specific situations, but SIGUSRs ...
41
votes
3answers
19k views

A list of available DBus services

Is there such a thing as list of available DBus services? I've stumbled upon a few (like those provided by NetworkManager, Rhythmbox, Skype, HAL). I wonder if I can find a rather complete list of ...
2
votes
1answer
756 views

Preventing ChromeOS from blanking the screen when working on a different tty

I am running Archlinux in a chroot alongside Chrome OS on a chromebook. The original project is there, my fork of it is here (mostly similar). The issue is that the display power management of Chrome ...
6
votes
1answer
4k views

How can I determine the connection method used by a MySQL client?

When using a MySQL client (e.g. mysql) how can I determine whether it connected to the server using a Unix socket file or by using TCP/IP?
3
votes
2answers
876 views

IPC: Shared memory killed process notification

In shared memory system, when two processes share a shared memory segment, after one process is killed, how will the other running process be notified of the killed process by the shared memory system ...
4
votes
1answer
13k views

How do I increase the number of semaphore arrays in Linux?

In a Debian lenny server running postgresql, I noticed that a lack of semaphore arrays is preventing Apache from starting up. Looking at the limits, I see 128 arrays used out of 128 arrays maximum, ...
13
votes
2answers
3k views

Is there a way to intercept interprocess communication in Unix/Linux?

For intercepting/analyzing network traffic, we have a utility called Wireshark. Do we have a similar utility for intercepting all the interprocess communication between any two processes in Unix/...