How to Exchange Data Between Processes in Linux?

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In Linux, there are several ways to exchange data between processes (Inter Process Communication IPC). Here are some of the commonly used methods:

Process Sharing/Exchanging Data using Pipes

Pipes are a simple way to exchange data between processes. A pipe is a unidirectional communication channel that allows one process to send data to another process. Pipes are created using the pipe system call and can be used for inter-process communication (IPC) between related processes, such as a parent process and its child process.

The Advantages of using Pipes to Exchange Data Between Processes under Linux are:

• Simple and easy to use.
• Good for communication between related processes.
• Can be used for both standard output and error channels.
• Efficient for small amounts of data.

And the Cons of using Pipes as IPC are:

• Unidirectional, can only be used for one-way communication.
• Limited capacity, can only hold a finite amount of data.
• Only suitable for communication between related processes.

Using Message Queues to Exchange Data Between Processes

Message queues (MQ) are another way to exchange data between processes. A message queue is a mechanism that allows processes to send and receive messages. Each message has a type and a data payload. Processes can send messages to a queue using the msgsnd system call, and receive messages from the queue using the msgrcv system call.

The Pros of using Message Queues to Share Data Between Processes are:

• Simple and easy to use.
• Can be used for inter-process communication between unrelated processes.
• Supports priority messages.
• Multiple processes can read from the same message queue.

And there are disadvantages of using Message Queues, which are:

• Slower than pipes or shared memory.
• Limited message size.
• Can be complex to manage multiple queues and messages.

Data Sharing Between Processes using Shared Memory

Shared memory is a mechanism that allows processes to share a portion of their memory. This can be used to exchange large amounts of data between processes without the overhead of copying data between processes. Shared memory is created using the shmget system call and accessed using the shmat and shmdt system calls.

The advantages of using Shared Memory between Processes are:

• Efficient for large amounts of data.
• Fastest method of inter-process communication.
• Allows multiple processes to access the same data simultaneously.

And the Cons of using Share Memory are:

• Complex to use and manage.
• Requires careful synchronization to avoid race conditions.
• Vulnerable to shared memory leaks and other security issues.

Using Sockets to Exchange Data Between Processes

Sockets are a mechanism for communication between processes over a network. They can also be used for communication between processes on the same system. Sockets provide a bidirectional communication channel, and can be used with various protocols such as TCP/IP, UDP, and Unix domain sockets.

There are several benefits of using sockets to share and exchange data between processes under Linux:

• Can be used for communication between unrelated processes.
• Supports various protocols for network communication.
• Provides bidirectional communication.

It also comes with some disadvantages:

• Requires complex setup and management.
• Slower than pipes and shared memory for inter-process communication on the same machine.
• Overhead of protocol handling

Process Data Sharing via Signals

Signals are a way for processes to send notifications to each other. A process can send a signal to another process using the kill system call. Signals can be used to notify a process of an event or to interrupt a process.

Pros of using signals to exchange data between processes in Linux:

• Simplicity: Signals are easy to use and implement. They provide a simple mechanism for inter-process communication. Signals are relatively simple to use and can be implemented quickly and easily.
• Efficiency: Signals are a lightweight mechanism for communication between processes.
• Standard: Signals are a standard feature of Linux and are supported by most programming languages.
• Asynchronous: Signals are an asynchronous method of IPC, which means that a process can send a signal to another process at any time without waiting for a response.
• Lightweight: Signals are a lightweight mechanism for inter-process communication (IPC) because they involve only a small amount of data and require no shared memory or other IPC mechanisms.

Cons of using signals as a main method to exchange data between processes are:

• Limited Data Size: Signals are limited in the amount of data that can be exchanged, as they can only pass a small amount of information in the signal handler.
• Unreliable: Signals are not a reliable method of IPC because they can be lost or blocked, and there is no guarantee that the receiving process will handle the signal immediately.
• Overhead: Signal handling can introduce additional overhead and complexity to the code, as the signal handler must be designed to handle the signal correctly and efficiently.
• Non-deterministic: Signal handling can also introduce non-deterministic behavior into the code, as the order in which signals are handled is not guaranteed.

Signals can be a useful and lightweight method of IPC in Linux, but they have limitations and drawbacks that must be carefully considered before implementing them.

You can view a list of supported Signals at Linux OS via the following command:

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$ kill -l

$ kill -l

Here is a list:

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 1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL       5) SIGTRAP
 6) SIGABRT      7) SIGBUS       8) SIGFPE       9) SIGKILL     10) SIGUSR1
11) SIGSEGV     12) SIGUSR2     13) SIGPIPE     14) SIGALRM     15) SIGTERM
16) SIGSTKFLT   17) SIGCHLD     18) SIGCONT     19) SIGSTOP     20) SIGTSTP
21) SIGTTIN     22) SIGTTOU     23) SIGURG      24) SIGXCPU     25) SIGXFSZ
26) SIGVTALRM   27) SIGPROF     28) SIGWINCH    29) SIGIO       30) SIGPWR
31) SIGSYS      34) SIGRTMIN    35) SIGRTMIN+1  36) SIGRTMIN+2  37) SIGRTMIN+3
38) SIGRTMIN+4  39) SIGRTMIN+5  40) SIGRTMIN+6  41) SIGRTMIN+7  42) SIGRTMIN+8
43) SIGRTMIN+9  44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12 47) SIGRTMIN+13
48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14 51) SIGRTMAX-13 52) SIGRTMAX-12
53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9  56) SIGRTMAX-8  57) SIGRTMAX-7
58) SIGRTMAX-6  59) SIGRTMAX-5  60) SIGRTMAX-4  61) SIGRTMAX-3  62) SIGRTMAX-2
63) SIGRTMAX-1  64) SIGRTMAX

 1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL       5) SIGTRAP
 6) SIGABRT      7) SIGBUS       8) SIGFPE       9) SIGKILL     10) SIGUSR1
11) SIGSEGV     12) SIGUSR2     13) SIGPIPE     14) SIGALRM     15) SIGTERM
16) SIGSTKFLT   17) SIGCHLD     18) SIGCONT     19) SIGSTOP     20) SIGTSTP
21) SIGTTIN     22) SIGTTOU     23) SIGURG      24) SIGXCPU     25) SIGXFSZ
26) SIGVTALRM   27) SIGPROF     28) SIGWINCH    29) SIGIO       30) SIGPWR
31) SIGSYS      34) SIGRTMIN    35) SIGRTMIN+1  36) SIGRTMIN+2  37) SIGRTMIN+3
38) SIGRTMIN+4  39) SIGRTMIN+5  40) SIGRTMIN+6  41) SIGRTMIN+7  42) SIGRTMIN+8
43) SIGRTMIN+9  44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+12 47) SIGRTMIN+13
48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-14 51) SIGRTMAX-13 52) SIGRTMAX-12
53) SIGRTMAX-11 54) SIGRTMAX-10 55) SIGRTMAX-9  56) SIGRTMAX-8  57) SIGRTMAX-7
58) SIGRTMAX-6  59) SIGRTMAX-5  60) SIGRTMAX-4  61) SIGRTMAX-3  62) SIGRTMAX-2
63) SIGRTMAX-1  64) SIGRTMAX

Conclusion of Sharing and Exchanging Data Between Processes in Linux

Each of these methods has its advantages and disadvantages, and the choice of method depends on the specific requirements of the application.

–EOF (The Ultimate Computing & Technology Blog) —