What is kernel space programming?

What is kernel space programming?

User program or applications runs in a memory area called “user space”. The kernel program runs in another memory area called “kernel space”. Kernel program always runs in a supper access mode. So from programming point of view, kernel programming means power to access anything and everything in a system.

What is a kernel socket?

Kernel Connection Multiplexor (KCM) is a mechanism that provides a message based interface over TCP for generic application protocols. With KCM an application can efficiently send and receive application protocol messages over TCP using datagram sockets.

How do I run a program in kernel space?

If you want to execute code in kernel space you have two options: build it in to the kernel, or load it with a kernel module. By user program I mean a program compiled to run in user space i.e by exec* system calls or any other way.

How do I transfer data from kernel space to user space?

The function copy_to_user is used to copy data from the kernel address space to the address space of the user program. For example, to copy a buffer which has been allocated with kmalloc to the buffer provided by the user.

Why do we need kernel space?

kernel space and user space is about the system protection, to make the system more robust. kernel space is privileged mode and can do things (like directly interacting with hardware/system resources) which user space cannot. All the user space interaction with the hardware has to go through kernel space only.

Is kernel a programming language?

The kernel is written in the C programming language [c-language]. More precisely, the kernel is typically compiled with gcc [gcc] under -std=gnu11 [gcc-c-dialect-options]: the GNU dialect of ISO C11.

Why socket is used in Linux?

Sockets are a way to enable inter-process communication between programs running on a server, or between programs running on separate servers. Communication between servers relies on network sockets, which use the Internet Protocol (IP) to encapsulate and handle sending and receiving data.

What is a kernel coded in?

Linux kernel

Tux the penguin, mascot of Linux
Linux kernel 3.0.0 booting
Repository git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Written in C (most in C89, switch to C11 planned), Assembly language
Available in English

How do I run a Linux kernel program?

The basic way is to add the code to the kernel source tree and recompile the kernel. A more efficient way is to do this is by adding code to the kernel while it is running. This process is called loading the module, where module refers to the code that we want to add to the kernel.

What is the difference between user space and kernel space?

Kernel space is strictly reserved for running a privileged operating system kernel, kernel extensions, and most device drivers. In contrast, user space is the memory area where application software and some drivers execute.

Which programming language is used in Linux kernel?

standard C programming language
Most of the Linux kernel code is written using the GNU extensions of GCC to the standard C programming language and with the use of architecture-specific instructions (ISA). This produces a highly optimized executable (vmlinux) with respect to utilization of memory space and task execution times.

Why do we need user space and kernel space?

Kernel space and user space is the separation of the privileged operating system functions and the restricted user applications. The separation is necessary to prevent user applications from ransacking your computer.

What are sockets in network programming?

Network programming is usually done with sockets. A socket serves as a communication end point between two processes. In this article, we describe network programming with TCP/IP sockets. Server programs create sockets, bind to well-known ports, listen and accept connections from clients.

What is SYS_socket () function in Linux kernel?

Eventually, the sys_socket () function in the kernel is responsible for creating the socket of specified address and family type, finding an unused file descriptor and returning this number back to user space. Browsing through the kernel’s code we can trace the path followed by this function (Figure 3). Figure 3.

What is kernel-space Netlink?

Kernel-Space Netlink APIs The kernel-space netlink API is supported by the netlink core in the kernel, net/core/af_netlink.c. From the kernel side, the API is different from the user-space API. The API can be used by kernel modules to access the netlink socket and to communicate with user-space applications.

What are the various IPC methods between kernel and user space?

The answer is the various IPC methods that exist between kernel and user space, such as system call, ioctl, proc filesystem or netlink socket. This article discusses netlink socket and reveals its advantages as a network feature-friendly IPC. Netlink socket is a special IPC used for transferring information between kernel and user-space processes.