Print some information of all the processes pointed by init_task, something similiar to "ps -ef", including UID, PID, PPID, thread name, etc.
Create five kernel threads using the following methods:
Create 2 threads using kernel_thread()
Create 3 threads using kthread_create()
Print some information of all the processes including the five threads. The output will be part of dmesg or messages. Try to follow the "ps -ef" format when printing all the processes including your own threads.
See the sample output below that shows the process list and the boot time messages.
Example: process list ("$ps -ef")
UID PID PPID C STIME TTY TIME CMD
root 1 0 0 09:36 ? 00:00:00 /sbin/init
root 2 0 0 09:36 ? 00:00:00 [kthreadd]
root 3 2 0 09:36 ? 00:00:00 [ksoftirqd/0]
root 4 2 0 09:36 ? 00:00:00 [migration/0]
root 5 2 0 09:36 ? 00:00:00 [watchdog/0]
root 6 2 0 09:36 ? 00:00:00 [events/0]
root 7 2 0 09:36 ? 00:00:00 [khelper]
root 10 2 0 09:36 ? 00:00:00 [kstop/0]
root 145 2 0 09:36 ? 00:00:00 [kintegrityd/0]
root 147 2 0 09:36 ? 00:00:00 [kblockd/0]
...
root 579 2 0 09:36 ? 00:00:00 [hid_compat]
root 612 1 0 09:36 ? 00:00:00 [My name:my_d]
root 613 1 0 09:36 ? 00:00:00 [My name:my_d]
root 614 2 0 09:36 ? 00:00:00 [my_kernel_threa]
root 615 2 0 09:36 ? 00:00:00 [my_kernel_threa]
root 616 2 0 09:36 ? 00:00:00 [my_kernel_threa]
root 632 2 0 09:37 ? 00:00:00 [kjournald]
root 681 1 0 09:37 ? 00:00:00 /sbin/udevd -d
...
For creating the first 2 threads try the following procedure:
Declare the functions that will create threads and those threads that will actually do something:
static void my_kernel_thread_create_1(void);
static void my_kernel_thread_create_2(void);
...
static void my_kernel_thread_create_1(void){
int mypid;
printk(KERN_NOTICE "My name: Calling kernel_thread(m_k_t_do_something_1)n");
mypid = kernel_thread(m_k_t_do_something_1, NULL, CLONE_KERNEL);
printk(KERN_NOTICE "My name: m_k_t_do_something_1 = %dn", mypid);
}
static void my_kernel_thread_create_2(void){
int mypid;
printk(KERN_NOTICE "My name: Calling kernel_thread(m_k_t_do_something_2)n");
mypid = kernel_thread(m_k_t_do_something_2, NULL, CLONE_KERNEL);
printk(KERN_NOTICE "My name: m_k_t_do_something_2 = %dn", mypid);
}
...
static void m_k_t_do_something_1(void){
struct task_struct *curtask = current;
strcpy(curtask->comm, "My name: m_k_t_do_something_1");
set_task_state(curtask, TASK_RUNNING);
printk(KERN_NOTICE "My name: m_k_t_do_something_1 is about to be scheduled.n");
schedule();
printk(KERN_NOTICE "My name: m_k_t_do_something_1 is now scheduled.n");
}
static void m_k_t_do_something_2(void){
struct task_struct *curtask = current;
strcpy(curtask->comm, "My name: m_k_t_do_something_2");
set_task_state(curtask, TASK_RUNNING);
printk(KERN_NOTICE "My name: m_k_t_do_something_2 is about to be scheduled.n");
schedule();
printk(KERN_NOTICE "My name: m_k_t_do_something_2 is now scheduled.n");
}
...
Call those functions that will create these threads.
...
print some info on all the processes on runqueue;
...
printk(KERN_NOTICE "My name: m_k_t_do_something threads are about to be created.n");
my_kernel_thread_create_1();
my_kernel_thread_create_2();
...
printk(KERN_NOTICE "My name: m_k_t_do_something threads are created.n");
...
print some info on all the processes on runqueue;
...
run_init_process("/sbin/init");
...
Remember to print process info before you call these functions, after you calll the functions, and after terminate
For creating the last 3 threads try the following procedure:
Declare the functions that create threads and those threads that actually do something like the above.
Use kthread_create() to create kernel threads. kthread_create() adds the newly created kernel thread to the global list kthread_create_list, as we discussed in class.
See apm_init() as an example.
static int __init apm_init(void){
...
kapmd_task = kthread_create(apm, NULL, "kapmd");
...
}
For printing some info on processes, try the following:
...
struct task_struct *tmp_tsk;
...
tmp_tsk = current;
for_each_process(tmp_tsk) {
...
print some info on all the processes on runqueue;
...
}
Now, remove all the threads you created and print all the processes, something similiar to "ps -ef".