c - cross memory attach. How do I get the remote address from a child process to a parent process

Question

Linux Kernel version 3.2 and further have a capability called cross memory attach.

Here is the link to it. I was not able to get a lot of help in that regard. http://man7.org/linux/man-pages/man2/process_vm_readv.2.html

In the syntax we need the address of the remote memory where we want to write to or read from. My question is how do I get the address of this remote memory if I am using fork().

Suppose I am sending something from parent process to child process using cross memory attach. How do I send the address of the remote memory to the parent process from the child process?

Answer 1

The system calls process_vm_readv and process_vm_writev are meant for fast data transfer between processes. They are supposed to be used in addition to some traditional way of interprocess communication.

For example, you may use a regular pipe or fifo to transfer the required addresses between your processes. Then you may use those addresses to establish faster process_vm_ communication. The simpliest way to transfer something between forked processes should be the pipe() function (man 2 pipe has a good example of its usage). There are many other ways to do so of course, like using sockets or messages. You can even write an address to a file and let the other process read it.