ioperm - 設置端口輸入/輸出權限

內容簡介

#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.

這個調用主要是為i386體係結構。在許多其它體係結構不存在或將總是返回一個錯誤。

返回值

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

錯誤

標簽	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.

遵循於

ioperm() 是Linux特有的，應在擬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.

另請參閱

• iopl (2)