NAME    [Toc]    [Back]

     ksyms - kernel symbol table device

SYNOPSIS    [Toc]    [Back]

     pseudo-device ksyms [count]

DESCRIPTION    [Toc]    [Back]

     The /dev/ksyms device masquerades as an OpenBSD native  executable (a.out
     or ELF, depending on the platform) with the symbols from the
running kernel
 as its symbol segment.  Use of /dev/ksyms requires  that
the boot
     loader preserve the kernel symbols and place them at the end
of the kernel's
 address space.

     The /dev/ksyms device is used to look up  the  symbol  table
name list from
     the  running kernel.  Because it represents the running kernel it is guaranteed
 to always be up to date even if the kernel  file  has
been changed
     (or  is  even non-existent).  It is most useful when used in
conjunction
     with nlist(3) or the kvm(3) routines (note that  kvm_open(3)
and
     kvm_openfiles(3)  will  try  /dev/ksyms automatically if the
first parameter
     to them is the NULL pointer).

FILES    [Toc]    [Back]

     /dev/ksyms

ERRORS    [Toc]    [Back]

     An open of /dev/ksyms will fail if:

     [EPERM]       An open was attempted with write  permissions.

     [ENXIO]       No kernel symbols were saved by the boot loader (usually
                   because they were removed with  strip(1)),  or
the kernel has
                   been   compiled   without   a  ``pseudo-device
ksyms'' line.

SEE ALSO    [Toc]    [Back]

     kvm(3), nlist(3)

HISTORY    [Toc]    [Back]

     The /dev/ksyms device appeared in OpenBSD 2.4.

BUGS    [Toc]    [Back]

     It is not possible to mmap(2) /dev/ksyms  because  the  boot
loader does not
     load  the  symbol  table  onto a page boundary (so it is not
page aligned).
     If all the boot loaders were fixed, mmap(2) support would be
trivial.

OpenBSD      3.6                          August     24,     1998