1 files changed, 12 insertions, 13 deletions

diff --git a/zh_CN.GB2312/books/arch-handbook/driverbasics/chapter.sgml b/zh_CN.GB2312/books/arch-handbook/driverbasics/chapter.sgml
index 299382ca32..15d27e76d6 100644
--- a/zh_CN.GB2312/books/arch-handbook/driverbasics/chapter.sgml
+++ b/zh_CN.GB2312/books/arch-handbook/driverbasics/chapter.sgml
@@ -2,7 +2,7 @@
      The FreeBSD Documentation Project
      The FreeBSD Simplified Chinese Project
 
-     Original Revision: 1.34
+     Original Revision: 1.36
      $FreeBSD$
 -->
 
@@ -240,14 +240,13 @@ static struct cdevsw echo_cdevsw = {
 	-1
 };
 
-struct s_echo {
+typedef struct s_echo {
 	char msg[BUFFERSIZE];
 	int len;
 } t_echo;
 
 /* 变量 */
 static dev_t sdev;
-static int len;
 static int count;
 static t_echo *echomsg;
 
@@ -337,13 +336,13 @@ echo_write(dev_t dev, struct uio *uio, int ioflag)
 {
 	int err = 0;
 
-	/* 将字符串从用户空间的内存拷贝到内核空间 */
+	/* 将字符串从用户空间的内存复制到内核空间 */
 	err = copyin(uio->uio_iov->iov_base, echomsg->msg,
-	    MIN(uio->uio_iov->iov_len,BUFFERSIZE - 1));
+	    MIN(uio->uio_iov->iov_len, BUFFERSIZE - 1));
 
 	/* 现在需要以null结束字符串，并记录长度 */
-	*(echomsg->msg + MIN(uio->uio_iov->iov_len,BUFFERSIZE - 1)) = 0;
-	echomsg->len = MIN(uio->uio_iov->iov_len,BUFFERSIZE);
+	*(echomsg->msg + MIN(uio->uio_iov->iov_len, BUFFERSIZE - 1)) = 0;
+	echomsg->len = MIN(uio->uio_iov->iov_len, BUFFERSIZE);
 
 	if (err != 0) {
 		uprintf("Write failed: bad address!\n");
@@ -474,9 +473,9 @@ echo_read(struct cdev *dev, struct uio *uio, int ioflag)
 	 * 这个读操作有多大？
 	 * 等于用户请求的大小，或者等于剩余数据的大小。
 	 */
-	 amt = MIN(uio->uio_resid, (echomsg->len - uio->uio_offset > 0) ?
+	amt = MIN(uio->uio_resid, (echomsg->len - uio->uio_offset > 0) ?
 	     echomsg->len - uio->uio_offset : 0);
-	if ((err = uiomove(echomsg->msg + uio->uio_offset,amt,uio)) != 0) {
+	if ((err = uiomove(echomsg->msg + uio->uio_offset, amt, uio)) != 0) {
 		uprintf("uiomove failed!\n");
 	}
 	return(err);
@@ -491,13 +490,13 @@ echo_write(struct cdev *dev, struct uio *uio, int ioflag)
 {
 	int err = 0;
 
-	/* 将字符串从用户空间的内存拷贝到内核空间 */
+	/* 将字符串从用户空间的内存复制到内核空间 */
 	err = copyin(uio->uio_iov->iov_base, echomsg->msg,
-	    MIN(uio->uio_iov->iov_len,BUFFERSIZE));
+	    MIN(uio->uio_iov->iov_len, BUFFERSIZE - 1));
 
 	/* 现在需要以null结束字符串，并记录长度 */
-	*(echomsg->msg + MIN(uio->uio_iov->iov_len,BUFFERSIZE)) = 0;
-	echomsg->len = MIN(uio->uio_iov->iov_len,BUFFERSIZE);
+	*(echomsg->msg + MIN(uio->uio_iov->iov_len, BUFFERSIZE - 1)) = 0;
+	echomsg->len = MIN(uio->uio_iov->iov_len, BUFFERSIZE);
 
 	if (err != 0) {
 		uprintf("Write failed: bad address!\n");