KSYMS(4) BSD Kernel Interfaces Manual KSYMS(4)NAMEksyms — kernel symbol table interface
SYNOPSIS
pseudo-device ksymsDESCRIPTION
The /dev/ksyms character device provides a read-only interface to the
current kernel symbol table. It can be accessed either as a sequential
file, where it looks like an executable file but with zero-sized text and
data segments, or via ioctl(2).
/dev/ksyms represents the symbol table at the time when the device is
opened, and may not change until it is closed.
The in-kernel symbol manager is designed to be able to handle any type of
symbol table. However, only elf(5) symbol tables are currently dealt
with.
IOCTLS
The ioctl(2) command codes below are defined in <sys/ksyms.h>.
The (third) argument to the ioctl(2) should be a pointer to the type
indicated.
KIOCGSIZE (int)
Returns the total size of the current symbol table. This
should be used when allocating a buffer to read in the
whole symbol table to memory.
KIOCGVALUE (struct ksyms_gsymbol)
Returns the value for the given symbol name in a symtab-
independent fashion.
struct ksyms_gsymbol {
const char *kg_name;
unsigned long *kg_value;
};
The struct element kg_name should be set to the name of the
requested value, and the address that kg_value points to
will receive the symbol value.
KIOCGSYMBOL (struct ksyms_gsymbol)
Returns the complete symbol for the given symbol name.
struct ksyms_gsymbol {
const char *kg_name;
void *kg_sym;
};
The struct element kg_name should be set to the name of the
requested symbol, and the found symbol will be written to
the kg_sym address. It is the callers responsibility to
ensure that enough space for the symbol is allocated.
FILES
/dev/ksyms
SEE ALSOioctl(2), nlist(3), elf(5)HISTORY
A ksyms device exists in many different operating systems. This imple‐
mentation is modelled in function after Solaris ksyms. This ksyms driver
was written by Anders Magnusson for NetBSD.
The ksyms driver first appeared in NetBSD 2.0.
BSD November 12, 2008 BSD
