I386_GET_LDT(2) |
System Calls Manual (i386) |
I386_GET_LDT(2) |
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.