ioperm - 设置端口输入/输出权限

内容简介

#include <unistd.h> /* for libc5 */ 
#include <sys/io.h> /* for glibc */

int ioperm(unsigned long from, unsigned long num, int turn_on);

描述

Ioperm sets the port access permission bits for the process for num bytes starting from port address from to the value turn_on. The use of ioperm() requires root privileges.

Only the first 0x3ff I/O ports can be specified in this manner. For more ports, the iopl() function must be used. Permissions are not inherited on fork(), but on exec() they are. This is useful for giving port access permissions to non-privileged tasks.

这个调用主要是为i386体系结构。在许多其它体系结构不存在或将总是返回一个错误。

返回值

On success, zero is returned. On error, -1 is returned, and errno is set appropriately.

错误

标签	描述
EINVAL	Invalid values for from or num.
EIO	(on ppc) This call is not supported.
EPERM	The calling process has insufficient privilege to call ioperm(); theCAP_SYS_RAWIO capability is required.

遵循于

ioperm() 是Linux特有的，应在拟移植的程序不能使用。

注意

Libc5 treats it as a system call and has a prototype in <unistd.h>. Glibc1 does not have a prototype. Glibc2 has a prototype both in <sys/io.h> and in <sys/perm.h>. Avoid the latter, it is available on i386 only.

另请参阅

• iopl (2)