Originální popis anglicky:
ioperm - set port input/output permissions
Návod, kniha: Linux Programmer's Manual
#include <unistd.h> /* for libc5 */
#include <sys/io.h> /* for glibc */
int ioperm(unsigned long from, unsigned long num,
int turn_on);
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.
This call is mostly for the i386 architecture. On many other architectures it
does not exist or will always return an error.
On success, zero is returned. On error, -1 is returned, and
errno is set
appropriately.
- 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; the CAP_SYS_RAWIO capability is required.
ioperm is Linux specific and should not be used in programs intended to
be portable.
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.
iopl(2),
capabilities(7)
