169     if (current_pcb->fds[fd_num] == NULL)  in sys_read()
175     struct vfs_file_t *file_ptr = current_pcb->fds[fd_num];  in sys_read()
208     if (current_pcb->fds[fd_num] == NULL)  in sys_write()
214     struct vfs_file_t *file_ptr = current_pcb->fds[fd_num];  in sys_write()
244     if (current_pcb->fds[fd_num] == NULL)  in sys_lseek()
247     struct vfs_file_t *file_ptr = current_pcb->fds[fd_num];  in sys_lseek()
282         return current_pcb->mm->brk_start;  in sys_brk()
287         return current_pcb->mm->brk_end;  in sys_brk()
289     if (new_brk > current_pcb->addr_limit) // 堆地址空间超过限制  in sys_brk()
293     if (new_brk >= current_pcb->mm->brk_end)  in sys_brk()
294         offset = (int64_t)(new_brk - current_pcb->mm->brk_end);  in sys_brk()
296         offset = -(int64_t)(current_pcb->mm->brk_end - new_brk);  in sys_brk()
298     new_brk = mm_do_brk(current_pcb->mm->brk_end, offset); // 扩展堆内存空间  in sys_brk()
300     current_pcb->mm->brk_end = new_brk;  in sys_brk()
312     uint64_t retval = current_pcb->mm->brk_end;  in sys_sbrk()
317         if (new_brk > current_pcb->addr_limit) // 堆地址空间超过限制  in sys_sbrk()
325 …      if ((__int128_t)current_pcb->mm->brk_end + (__int128_t)regs->r8 < current_pcb->mm->brk_start)  in sys_sbrk()
329     uint64_t new_brk = mm_do_brk(current_pcb->mm->brk_end, (int64_t)regs->r8); // 调整堆内存空间  in sys_sbrk()
331     current_pcb->mm->brk_end = new_brk;  in sys_sbrk()
437     struct vfs_file_t *filp = current_pcb->fds[fd];  in sys_getdents()
522         wait_queue_sleep_on_interriptible(&current_pcb->wait_child_proc_exit);  in sys_wait4()