【kernel新手培训之进阶练习2】 查找进程的pid

【kernel进阶练习2】 查找进程的pid

注意2.4和2.6 kernel的struct task_struct 已经发生变化了。 原来2.4里面的struct task_struct *task_next 已经没有了， 变成了现在的struct list_head tasks 了。
所以编程时候要注意。

    /*
By process name , you can get task_struct for which wake up ,bob added
*/
int self_find_task_by_name(char *ps_name)
{
    pid_t pid = -1;
    // int counter = 0;


    //2.4

    //struct task_struct *p = current->next_task;

    //struct task_struct *p_query_head = current ;


    //2.6

    struct list_head *p = NULL;
    struct list_head *head = &current->tasks;

    //loop times depends on the number of the process in current system

    //2.4

    //while(p != NULL && p->pid != p_query_head->pid)

    //2.6 kernel

    list_for_each(p,head)
    {
        
#define this_task(p)    list_entry(p,struct task_struct, tasks) //我自己定义的一个宏 ，可以直接把list_head 指针的宿主指针找出来。


        struct task_struct *task = NULL;
        task = this_task(p);
        
        if( ! memcmp(task->comm,ps_name,strlen(ps_name)))
        {
            pid = task->pid;
            goto p_find;
        }
    }
    dbg("Can't find the process named %s,you should run it in advance\n",ps_name);
    return -1;

p_find:
    return pid;

}