i386_get_ldt, i386_set_ldt - manage i386 per-process Local
i386_get_ldt(int start_sel, union descriptor *descs, int
i386_set_ldt(int start_sel, union descriptor *descs, int
i386_get_ldt() will return the list of i386 descriptors that
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
number start_sel, an array of memory that will contain the
be set or returned descs, and the number of entries to set
The argument descs can be either segment_descriptor or
as defined in <i386/segments.h>. These structures are defined by the architecture
as disjoint bit-fields, so care must be taken in
Before this API can be used the functionality has to be enabled using the
machdep.userldt sysctl(8) variable.
Note: Code using the i386_get_ldt() and i386_set_ldt() functions must be
compiled using -li386.
Upon successful completion, i386_get_ldt() returns the number of descriptors
currently in the LDT. i386_set_ldt() returns the first
set. Otherwise, a value of -1 is returned and the global
is set to indicate the error.
i386_get_ldt() and i386_set_ldt() will fail if:
[EINVAL] An inappropriate parameter was used for start_sel
[EACCES] The caller attempted to use a descriptor that
protection or cause a failure.
Intel, i386 Microprocessor Programmer's Reference Manual.
You can really hose your process using this.
OpenBSD 3.6 September 20, 1993
[ Back ]