How does user space and kernel space communicate?
Communication between user-space and kernel space using Netlink sockets. As mentioned in Linux kernel souce code net/netlink/af_netlink. c, netlink is a Kernel-user communication protocol which allows user to send and receive data to Linux kernel using sockets as we do for other socket communication.
What is user space and kernel space program?
Kernel space is that area of virtual memory where kernel processes will run and user space is that area of virtual memory where user processes will be running. This division is required for memory access protections.
How do you send a signal from kernel space to user space?
Using the following steps easily we can send the signals.
- Decide the signal that you want to send.
- Register the user space application with the driver.
- Once something happened (in our example we used interrupts) send signals to userspace.
- Unregister the user space application when you have done with it.
How is kernel space and user space interface?
3.2 Kernel and user space The kernel provides certain services, and user space, that is, everything outside the kernel, both libraries and application programs, uses these. Programs in user space contain system calls that ask the kernel to do something, and the kernel does so, or returns an error code.
What is netlink socket?
Netlink socket is a special IPC used for transferring information between kernel and user-space processes. It provides a full-duplex communication link between the two by way of standard socket APIs for user-space processes and a special kernel API for kernel modules.
What is a user space program?
User space refers to all of the code in an operating system that lives outside of the kernel. Most Unix-like operating systems (including Linux) come pre-packaged with all kinds of utilities, programming languages, and graphical tools – these are user space applications. We often refer to this as “userland.”
What is kernel space?
Kernel space is where the kernel (i.e., the core of the operating system) executes (i.e., runs) and provides its services. User space is that set of memory locations in which user processes (i.e., everything other than the kernel) run. A process is an executing instance of a program.
What is stored in kernel space?
What is Af_inet and Pf_inet?
Meaning, AF_INET refers to addresses from the internet, IP addresses specifically. PF_INET refers to anything in the protocol, usually sockets/ports.
How is communication between Linux kernel and user space program?
The kernel processing returns the result upon completion. Instead of using normal sockets, proc fs and implementing a new system call, Use netlink sockets which offers full duplex communication between user space programs and kernel modules. Thanks for contributing an answer to Stack Overflow!
How does kernel read data from user space?
When the data is ready, kernel will set that variable. In user space, the application can poll the variable. When set, an ioctl can be done to read the data from the kernel. The drawback is that you will have to poll the variable in user space in every defined time but the upside is that you can avoid the locking mechanisms.
How to share status of a kernel module?
For sharing status information of your kernel module, I suggest using any one of the virtual filesystems available (eg: /proc, /sys or if you’re debugging debugfs ).