NAME
i386_get_ldt,
i386_set_ldt —
manage i386 per-process Local Descriptor Table entries
LIBRARY
i386 Architecture Library (libi386, -li386)
SYNOPSIS
#include <sys/types.h>
#include <machine/segments.h>
#include <machine/sysarch.h>
int
i386_get_ldt(
int
start_sel,
union descriptor
*descs,
int
num_sels);
int
i386_set_ldt(
int
start_sel,
union descriptor
*descs,
int
num_sels);
DESCRIPTION
i386_get_ldt() will return the list of i386 descriptors that
the process has in its LDT.
i386_set_ldt() will set a list
of i386 descriptors for the current process in its LDT. Both routines accept a
starting selector number
start_sel , an array of memory
that will contain the descriptors to be set or returned
descs , and the number of entries to set or return
num_sels.
The argument
descs can be either segment_descriptor or
gate_descriptor and are defined in
<i386/segments.h> .
These structures are defined by the architecture as disjoint bit-fields, so
care must be taken in constructing them.
RETURN VALUES
Upon successful completion,
i386_get_ldt() returns the number
of descriptors currently in the LDT.
i386_set_ldt() returns
the first selector set. Otherwise, a value of -1 is returned and the global
variable
errno is set to indicate the error.
ERRORS
i386_get_ldt() and
i386_set_ldt() will fail
if:
-
-
- [
EINVAL
]
- An inappropriate parameter was used for
start_sel or num_sels.
-
-
- [
EACCES
]
- The caller attempted to use a descriptor that would
circumvent protection or cause a failure.
REFERENCES
i386 Microprocessor Programmer's Reference Manual, Intel
WARNING
You can really hose your process using this.