exit-wait.c

用于汇编领域的,运用于OS的MAIN函数.基于硬件基础的源代码

// exit and wait system call
#include "hos.h"
void release_body(struct task_struct *p){
//free the body of p
   unsigned long *dir=(unsigned long *)(mloc(p->mm.pgdir[0]));
   free_pgframe(mloc(dir[USER_PAGE])); // free the loaded program frame
   free_pgframe(p->mm.pgdir); // free the directory table
   free_pgframe(dir);  // free the directory 0 frame
   printk("frame freeed: %x %x %x\n", mloc(dir[USER_PAGE]), p->mm.pgdir, dir);
}

void do_exit(){
   printk("in do_exit\n");
   remove_from_run_q(current);
   release_body(current);
   // wake up parent
   wake_up(current->parent);
   current->need_reschedule=1; // parent will kill this process later
}

void do_wait(){ // for now, we assume parent always wait() bef child
   struct task_struct *child;
   printk("in do_wait\n");
   remove_from_run_q(current);
   current->need_reschedule=1; // to activate schedule() 
   schedule(); // schedule next process
   // if we are here, our child is dead. clean him
   child=find_child(current);
   remove_from_process_q(child);
   child->pid=-1; // kill it permanently
}