Linux start with start_kernel function in main.c. It has lots of function, such mm_init for kernel memory allocators. Let’s start with some very basic components firstly.<\/p>\n
task_struct is an basic and important struct for process.
\nIt is defined in “include\/linux\/sched.h”<\/p>\n
One process will be linked with others, for example, parent process and child process are linked together.<\/p>\n
each member of task_struct is very critical and it is better to go though all of them to understand its better.<\/p>\n
Check the definition of task_struct, you could print more information you want,<\/p>\n
\r\n#include \r\n#include \/* printk() *\/\r\n#include \/* error codes *\/\r\n#include \r\n \r\n \r\nMODULE_LICENSE(\"Dual BSD\/GPL\");\r\n \r\n\/* Declaration of functions *\/\r\nvoid device_exit(void);\r\nint device_init(void);\r\n \r\n\/* Declaration of the init and exit routines *\/\r\nmodule_init(device_init);\r\nmodule_exit(device_exit);\r\n \r\nint device_init(void)\r\n{\r\n struct task_struct *task = current; \/\/ getting global current pointer\r\n printk(KERN_NOTICE \"assignment: current process: %s, PID: %d\", task->comm, task->pid);\r\n do\r\n {\r\n task = task->parent;\r\n printk(KERN_NOTICE \"assignment: parent process: %s, PID: %d\", task->comm, task->pid);\r\n } while (task->pid != 0);\r\n return 0;\r\n}\r\n \r\nvoid device_exit(void) {\r\n printk(KERN_NOTICE \"assignment: exiting module\");\r\n}\r\n<\/pre>\n ![\"Screenshot](\"http:\/\/emacslisp.com\/wp-content\/uploads\/2016\/02\/Screenshot-from-2016-02-12-013943.png\")
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