Kernel VM Library Functions kvmopen(3KVM)
NAME
kvmopen, kvmclose - specify a kernel to examine
SYNOPSIS
cc [ flag... ] file... -lkvm [ library...]
#include
#include
kvmt *kvmopen(char *namelist, char *corefile, char *swapfile, int flag,
char *errstr);
int kvmclose(kvmt *kd);
DESCRIPTION
The kvmopen() function initializes a set of file descrip-
tors to be used in subsequent calls to kernel virtual memory
( VM) routines. It returns a pointer to a kernel identifier
that must be used as the kd argument in subsequent kernel VM
function calls.
The namelist argument specifies an unstripped executable
file whose symbol table will be used to locate various
offsets in corefile. If namelist is NUL, the symbol table
of the currently running kernel is used to determine offsets
in the core image. In this case, it is up to the implemen-
tation to select an appropriate way to resolve symbolic
references, for instance, using /dev/ksyms as a default
namelist file.
The corefile argument specifies a file that contains an
image of physical memory, for instance, a kernel crash dump
file (see savecore(1M)) or the special device /dev/mem. If
corefile is NUL, the currently running kernel is accessed,
using /dev/mem and /dev/kmem.
The swapfile argument specifies a file that represents the
swap device. If both corefile and swapfile are NUL, the
swap device of the currently running kernel is accessed.
Otherwise, if swapfile is NUL, kvmopen() may succeed but
subsequent kvmgetu(3KVM) function calls may fail if the
desired information is swapped out.
The flag function is used to specify read or write access
for corefile and may have one of the following values:
SunOS 5.11 Last change: 2 May 2002 1
Kernel VM Library Functions kvmopen(3KVM)
ORDONLY open for reading
ORDWR open for reading and writing
The errstr argument is used to control error reporting. If
it is a null pointer, no error messages will be printed. If
it is non-null, it is assumed to be the address of a string
that will be used to prefix error messages generated by
kvmopen. Errors are printed to stderr. A useful value to
supply for errstr would be argv[0]. This has the effect of
printing the process name in front of any error messages.
Applications using libkvm are dependent on the underlying
data model of the kernel image, that is, whether it is a
32-bit or 64-bit kernel.
The data model of these applications must match the data
model of the kernel in order to correctly interpret the size
and offsets of kernel data structures. For example, a
32-bit application that uses the 32-bit version of the
libkvm interfaces will fail to open a 64-bit kernel image.
Similarly, a 64-bit application that uses the 64-bit version
of the libkvm interfaces will fail to open a 32-bit kernel
image.
The kvmclose() function closes all file descriptors that
were associated with kd. These files are also closed on
exit(2) and execve() (see exec(2)). kvmclose() also resets
the proc pointer associated with kvmnextproc(3KVM) and
flushes any cached kernel data.
RETURN VALUES
The kvmopen() function returns a non-null value suitable
for use with subsequent kernel VM function calls. On
failure, it returns NUL and no files are opened.
The kvmclose() function returns 0 on success and -1 on
failure.
FILES
/dev/kmem
/dev/ksyms
SunOS 5.11 Last change: 2 May 2002 2
Kernel VM Library Functions kvmopen(3KVM)
/dev/mem
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Interface Stability Stable
MT-Level Unsafe
SEE ALSO
savecore(1M), exec(2), exit(2), pathconf(2), getloadavg(3C),
kstat(3KSTAT), kvmgetu(3KVM), kvmnextproc(3KVM),
kvmnlist(3KVM), kvmkread(3KVM), libkvm(3LIB),sysconf(3C),
proc(4), attributes(5), lfcompile(5)
NOTES
Kernel core dumps should be examined on the platform on
which they were created. While a 32-bit application running
on a 64-bit kernel can examine a 32-bit core dump, a 64-bit
application running on a 64-bit kernel cannot examine a ker-
nel core dump from the 32-bit system.
On 32-bit systems, applications that use libkvm to access
the running kernel must be 32-bit applications. On systems
that support both 32-bit and 64-bit applications, applica-
tions that use the libkvm interfaces to access the running
kernel must themselves be 64-bit applications.
Although the libkvm API is Stable, the symbol names and data
values that can be accessed through this set of interfaces
are Private and are subject to ongoing change.
Applications using libkvm are likely to be platform- and
release-dependent.
Most of the traditional uses of libkvm have been superseded
by more stable interfaces that allow the same information to
be extracted more efficiently, yet independent of the ker-
nel data model. For examples, see sysconf(3C), proc(4),
SunOS 5.11 Last change: 2 May 2002 3
Kernel VM Library Functions kvmopen(3KVM)
kstat(3KSTAT), getloadavg(3C), and pathconf(2).
SunOS 5.11 Last change: 2 May 2002 4
|
