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

6611

6612 /*

6613  * Convert a user supplied

6614  * file descriptor into a pointer

6615  * to a file structure.

6616  * Only task is to check range

6617  * of the descriptor.

6618  */

6619 getf(f)

6620 {

6621     register *fp, rf;

6622

6623     rf = f;

6624     if(rf<0 || rf>=NOFILE)

6625          goto bad;

6626     fp = u.u_ofile[rf];

6627     if(fp != NULL)

6628          return(fp);

6629 bad:

6630     u.u_error = EBADF;

• 抛出错误，错误代码:EBADF

6631     return(NULL);

6632 }

6633 /* ------------------------- */

• 文件系统
• 内存打开文件结构

• code:rdwr
• code:close
• code:seek
• code:fstat
• code:dup
• code:sgtty