KSYMS(4) BSD Programmer's Manual KSYMS(4)NAMEksyms - kernel symbol table device
SYNOPSIS
pseudo-device ksyms [count]
DESCRIPTION
The /dev/ksyms device masquerades as an OpenBSD native executable
(a.out or ELF, depending on the platform) with the symbols from the run-
ning 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 con-
junction 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
/dev/ksyms
ERRORS
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 ALSOkvm(3), nlist(3)HISTORY
The /dev/ksyms device appeared in OpenBSD 2.4.
BUGS
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.
MirOS BSD #10-current August 24, 1998 1
