The Art of Linux Kernel Design

3 Creation and Execution of Process 1

3.1 Creation of Process 1

Now, process 0 is at privilege level 3, which is a process state. As a parent process, its first task is to call fork() to create the first child process—process 1, which is the first implementation of the parent–child process-creating mechanism. On the basis of this mechanism, all processes are created by the parent process later.

3.1.1 Preparation for Creating Process 1

In Linux, any new process is created by calling fork(). The procedure is shown in Figure 3.1.

The code is as follows:

//code path:init/main.c:       ......static inline _syscall0(int,fork)//correspond to forkstatic ...