i386_set_ioperm(2) - NetBSD Manual Pages

I386_GET_IOPERM(2)     NetBSD/i386  Programmer's Manual     I386_GET_IOPERM(2)


NAME
i386_get_ioperm, i386_set_ioperm - manage i386 per-process I/O permission bitmap
LIBRARY
i386 Architecture Library (libi386, -li386)
SYNOPSIS
#include <sys/types.h> #include <machine/sysarch.h> int i386_get_ioperm(u_long *iomap); int i386_set_ioperm(u_long *iomap);
DESCRIPTION
i386_get_ioperm() copies the current I/O permission bitmap into the memo- ry referenced by iomap. i386_set_ioperm() sets the I/O permission bitmap from the data pointed to by iomap. This call is restricted to the super-user. The permission bitmap contains 1024 bits in 32 longwords. If bit n is clear in the bitmap, then access is granted to I/O port n. If bit n is set in the bitmap, then an attempt to access I/O port n results in deliv- ery of a SIGBUS signal unless the process's I/O permission level would grant I/O access. Bit #0 is the LSB of the first longword in the array.
RETURN VALUES
Upon successful completion, i386_get_ioperm() and i386_set_ioperm() re- turn 0. Otherwise, a value of -1 is returned and the global variable errno is set to indicate the error.
ERRORS
i386_get_ioperm() and i386_set_ioperm() will fail if: [EFAULT] Iomap points outside the process's allocated address space. [EPERM] The caller was not the super-user, or the operation was not permitted at the current security level.
SEE ALSO
i386_iopl(2)
REFERENCES
i386 Microprocessor Programmer's Reference Manual, Intel
WARNING
You can really hose your machine if you enable user-level I/O and write to hardware ports without care.
BUGS
The bitmap should really cover 65536 bits, but that's just too big for allocation in a kernel structure. If you need access to ports beyond 1024, use i386_iopl(2). NetBSD 1.6.2 October 14, 1995 1

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