code:closef - ikarishinjieva/unixV6-code-analyze-chs GitHub Wiki

6634

6635 /*

6636 * Internal form of close.

6637 * Decrement reference count on

6638 * file structure and call closei

6639 * on last closef.

6640 * Also make sure the pipe protocol

6641 * does not constipate.

6642 */

6643 closef(fp)

6644 int *fp;

6645 {

6646 register *rfp, *ip;

6647

6648 rfp = fp;

6649 if(rfp->f_flag&FPIPE) {

6650 ip = rfp->f_inode;

6651 ip->i_mode =& ~(IREAD|IWRITE);

6652 wakeup(ip+1);

6653 wakeup(ip+2);

6654 }

若fp是管道文件，ip是fp对应的inode

释放ip的读写标志

唤醒等待读/写 ip的进程

参看睡眠原因#(struct inode)+1

参看睡眠原因#(struct inode)+2

6655 if(rfp->f_count <= 1)

6656 closei(rfp->f_inode, rfp->f_flag&FWRITE);

若释放的是fp的最后一个引用，则释放fp对应inode

关于为什么标志位赋 &FWRITE ，并不清楚，列入遗留问题

6657 rfp->f_count--;

6658 }

6659 /* ------------------------- */