kextutil(8) BSD System Manager's Manual kextutil(8)
NAME
kextutil -- load, diagnose problems with, and generate symbols for kernel
extensions (kexts)
SYNOPSIS
kextutil [options] [--] [kext] ...
DESCRIPTION
The kextutil program is used to explicitly load kernel extensions
(kexts), diagnose problems with kexts, and to generate symbol files for
debugging kexts. In order to load a kext into the kernel kextutil must
run as the superuser; for all other uses it can run as any user.
kextutil is the developer utility for kext loading in the Darwin OS and
in Mac OS X. Software and installers should use kextload(8) instead of
this program.
The arguments and options available are these:
kext The pathname of a kext bundle to load or otherwise use. Kexts
can also be specified by CFBundleIdentifier with the -bundle-id
option.
-a identifier@address, -address identifier@address
Treat the kext whose CFBundleIdenfier is identifier as being
loaded at address when generating symbol files and not loading.
When generating symbols, any dependencies with unspecified
addresses are skipped. Use this option repeatedly to name every
nonkernel dependency for which you want symbols. This option
implies the use of the -no-load option. See also
-use-load-addresses and -no-load.
-arch Use the specified architecture for generating symbols and per-
forming tests. If loading into the kernel or getting load
addresses from the kernel, the specified arch must match that of
the running kernel.
-A, -use-load-addresses
When generating symbol files and not loading, look up all depen-
dency kext addresses within the running kernel. This option
implies the use of the -no-load option. See also -address and
-no-load.
-b identifier, -bundle-id identifier
Look up the kext whose CFBundleIdentifier is identifier within
the set of known kexts and load it. The kext of the highest
CFBundleVersion with the given identifier is used; in the case
of version ties, the last such kext specified on the command
line is used. See the -dependency, -no-system-extensions, and
-repository options for more information.
-c, -no-caches
Ignore any repository cache files and scan all kext bundles to
gather information. If this option is not given, kextutil
attempts to use cache files and (when running as root) to create
them if they are out of date or don't exist.
-d kext, -dependency kext
Add kext and its plugins to the set of known kexts for resolving
dependencies. This is useful for adding a single kext from a
directory. See ``Explicitly Specifying Dependencies'' for more
information, as well as the -no-system-extensions and
-repository options.
-e, -no-system-extensions
Don't use the contents of /System/Library/Extensions/ or
/Library/Extensions/ as the default repository of kexts. If you
use this option you will have to explicitly specify all depen-
dencies of the kext being loaded or otherwise worked on using
the -dependency and -repository options. See ``Explicitly
Specifying Dependencies'' for more information.
-h, -help
Print a help message describing each option flag and exit with a
success result, regardless of any other options on the command
line.
-i, -interactive
Interactive mode; pause after loading each specified kext and
wait for user input to start the kext and send its personalities
to the kernel. This allows for debugger setup when the kext
needs to be debugged during its earliest stages of running.
-I, -interactive-all
Interactive mode, as described above, for each specified kext
and all of their dependencies.
-k kernel_file, -kernel kernel_file
Link against the given kernel_file. Allowed only with the
-no-load option to generate debug symbols. By default kextutil
attempts to get link symbols from the kernel at /mach_kernel.
-l, -load-only
Load and start the kext only; don't send I/O Kit personalities
to the kernel to begin matching. Matching may still occur if
the personalities are present from an earlier load operation.
You may want to use kextunload(8) before loading a kext with
this option.
-m, -match-only
Don't load the kext, but do send its personalities to the kernel
to begin matching. Use this option after you have loaded a
driver with -load-only and after setting up the debugger.
-n, -no-load
Neither load the kext nor send personalities to the kernel.
This option is for use when generating debug symbols only with
the -symbols option, or when diagnosing kexts with the
-print-diagnostics option. For convenience in development, this
option implies the -no-authenticate option. See also the
-address and -use-load-addresses options.
-p personality, -personality personality
Send only the named personalities from the kext to the kernel.
Repeat for each personality desired, or use the -interactive
option to have kextutil ask for each personality.
-q, -quiet
Quiet mode; print no informational or error messages. If
kextutil is run with -quiet in a way that might require user
interaction, as with the -interactive and -interactive-all
options, and some uses of -no-load, the program silently exits
with an error status.
-r directory, -repository directory
Use directory as a repository of kexts. This adds to the set of
known kexts for resolving dependencies or looking up by
CFBundleIdentifier when using the -bundle-id option. This is
not recursive; only the directory's immediate contents (and
their plugins) are scanned. See ``Explicitly Specifying
Dependencies'' for more information, as well as the -dependency
and -no-system-extensions options.
-s directory, -symbols directory
Write all generated symbol files into directory. The directory
must already exist. Symbol files are named after the CFBundleI-
dentifier of each kext with a .sym suffix appended.
-t, -print-diagnostics
Perform all possible tests on the specified kexts, even with
options that implicitly disable some tests, and indicate whether
the kext is loadable, or if not, what problems it has. Note
that tests are performed in three stages, validation, authenti-
cation, and dependency resolution; a failure at any stage can
make tests in further stages impossible. Thus, a kext with val-
idation failures may have unreported authentication problems or
missing dependencies.
-v [0-6 | 0x####], -verbose [0-6 | 0x####]
Verbose mode; print information about program operation. Higher
levels of verbosity include all lower levels. By default
kextutil prints only warnings and errors. You can specify a
level from 0-6, or a hexadecimal log specification (as described
in kext_logging(8)). The levels of verbose output are:
0 Print only errors (that is, suppress warnings); see
also -quiet.
1 (or none) Print basic information about program operation.
2 Print basic information about the link/load opera-
tion.
3 Print more information about user-kernel interac-
tion, link/load operation, and processing of I/O
Kit Personalities.
4 Print detailed information about module start and
C++ class construction.
5 Print internal debug information, including checks
for loaded kexts.
6 Identical to level 5 but for all kexts read by the
program.
To ease debug loading of kexts, the verbose levels 1-6 in
kextutil implicitly set the OSBundleEnableKextLogging property
for each kext specified on the command line to true. See
kext_logging(8) for more information on verbose logging.
-x, -safe-boot
Run kextutil as if in safe boot mode (indicating startup with
the Shift key held down). Kexts that don't specify a proper
value for the OSBundleRequired info dictionary property will not
load. This option implies the use of the -no-caches option.
Note that if the system has actually started up in safe boot
mode, this option is redundant. There is no way to simulate
non-safe boot mode for a system running in safe boot mode.
-z, -no-authenticate
Don't authenticate kexts. This option is for convenience during
development, and is allowed only for operations that don't actu-
ally load a kext into the kernel (such as when generating sym-
bols).
-Z, -no-resolve-dependencies
Don't try to resolve dependencies. This option is allowed only
when using the -no-load and -print-diagnostics options to test a
kext for problems. It is not allowed with the -symbols option
as generating symbols requires dependencies to be resolved.
-- End of all options. Only kext names follow.
EXAMPLES
Here are the common uses and usage patterns for kextutil.
Basic Loading
To load a kext you must run kextutil as the superuser and supply a kext
bundle name; no options are required:
kextutil TabletDriver.kext
Alternatively, you can use the -bundle-id (-b) option to specify a kext
by its CFBundleIdentifier:
kextutil -b com.mycompany.driver.TabletDriver
With no additional options kextutil looks in /System/Library/Extensions/
and /Library/Extensions/ for a kext with the given CFBundleIdentifier.
Adding repository directories with the -repository (-r) option or indi-
vidual kexts with the -dependency (-d) option expands the set of kexts
that kextutil looks among:
kextutil -r ${USER}/Library/Extensions TabletDriver.kext
Diagnosing Kexts
kextutil prints diagnostic information about kexts by default, but some
options cause certain tests to be skipped. The ensure that all tests are
performed, use the -print-diagnostics (-t) option.
The -print-diagnostics option is typically used with -no-load (-n) after
a load failure to pinpoint a problem. It can be used with any other set
of options, however.
If you want to validate a kext in isolation, as in a build environment
where dependencies may not be available, you can use the
-no-system-extensions (-e) and -no-resolve-dependencies (-Z) options to
omit the /System/Library/Extensions/ and /Library/Extensions/ reposito-
ries and to suppress dependency resolution, respectively:
kextutil -entZ PacketSniffer.kext
Only validation and authentication checks are performed.
Generating Debug Symbols When Loading
To generate a symbol file for use with gdb when loading a kext, use the
-symbols (-s) option to specify a directory where symbol files will be
written for the kext being loaded and all its dependencies.
kextutil -s ~/ksyms PacketSniffer.kext
Generating Debug Symbols For an Already-Loaded Kext
If you want to generate symbols for a kext that's already loaded, whether
on the same system or on another, use the -symbols (-s) option along with
the -no-load (-n) option. Since in this case addresses must be known for
the kext and all its dependencies, though, you must specify them. If you
don't indicate them on the command line, kextutil asks for the load
address of each kext needed. To get these addresses you can use
kextstat(8) on the machine you're generating symbols for, the
showallkmods gdb(1) macro defined by the kgmacros file in the Kernel
Development Kit, or consult a panic backtrace.
kextutil -n -s ~/ksyms GrobbleEthernet.kext
enter the hexadecimal load addresses for these modules:
com.apple.iokit.IONetworkingFamily: 0x1001000
...
Alternatively, if you know the CFBundleIdentifiers of all the kexts, you
can use the -address (-a) option for each kext (you needn't specify
-no-load when using the -address option):
kextutil -s ~/ksyms \
-a com.apple.iokit.IONetworkingFamily@0x1001000 \
-a com.apple.iokit.IOPCIFamily@0x1004000 \
-a com.mycompany.driver.GrobbleEthernet@0x1007000 \
GrobbleEthernet.kext
Simplest of all, however, provided you can run kextutil on the same
machine as the loaded kext, is to use the -use-load-addresses (-A)
option, which checks with the kernel for all loaded kexts and automati-
cally gets their load addresses.
kextutil -s ~/ksyms -A GrobbleEthernet.kext
Explicitly Specifying Dependencies
Because kextutil resolves dependencies automatically, it's possible that
a kext other than the one you intend might get used as a dependency (as
when there are multiple copies of the same version, or if you're working
with a different version of a kext that's already in
/System/Library/Extensions/). By default, when loading a kext into the
kernel, kextutil checks which versions of possible dependencies are
already loaded in order to assure a successful load. When not loading
and not using -use-load-addresses, however, it always chooses the highest
versions of any dependencies, and in the case of a tie it chooses from
kexts specified on the command line using the -dependency or -repository
options, or as command line arguments (in decreasing order of priority).
For precise control over the set of extensions used to resolve dependen-
cies, use the -no-system-extensions (-e) option along with the
-dependency (-d), and -repository (-r) options. The
-no-system-extensions option excludes the standard
/System/Library/Extensions/ and /Library/Extensions/ directories, leaving
the set of candidate extensions for dependency resolution entirely up to
you. To specify candidate dependencies you use either -dependency (-d),
which names a single kext as a candidate, or -repository (-r), which adds
an entire directory of extensions.
kextutil -n -s ~/ksyms -e \
-d /System/Library/Extensions/System.kext \
-r ~/TestKexts -d JoystickSupport.kext JoystickDriver.kext
Note also that if you use -no-system-extensions (-e), you must supply at
least some version of System.kext in order to supply information about
the kernel. This should always match the kernel you're linking against,
which is by default the installed kernel on the machine you're using
kextutil on; you can use the -kernel (-k) option to specify a different
kernel file. You may also need to explicitly specify other library or
family kexts.
Debug Loading an I/O Kit Driver
Pure I/O Kit driver kexts have empty module-start routines, but trigger
matching and driver instance creation on load. If you need to debug an
I/O Kit driver's early startup code, you can load the driver on the tar-
get machine without starting matching by using the -load-only (-l)
option:
kextutil -l DiskController.kext
Once you have done this, you can use the generated symbol file in your
debug session to set breakpoints and then trigger matching by running
kextutil again on the target machine with the -match-only (-m) option:
kextutil -m DiskController.kext
You may wish to use the -personality (-p) option as well in order to send
selected personalities to the kernel. Alternatively, you can use the
-interactive (-i) option for the whole process, which causes kextutil to
pause just before loading any personalities and then to ask you for each
personality whether that one should be sent to the kernel:
kextutil -i DiskController.kext
DiskController.kext appears to be loadable (not including linkage
for on-disk libraries).
Load DiskController.kext and its dependencies into the kernel [Y/n]? y
Loading DiskController.kext.
DiskController.kext successfully loaded (or already loaded).
DiskController.kext and its dependencies are now loaded,
but not started (unless they were already running).
You may now set breakpoints in the debugger before starting them.
start DiskController.kext [Y/n]? y
DiskController.kext started.
send personalities for DiskController.kext [Y/n]? y
send personality Test Match Personality [Y/n]? y
Debug Loading a Kext with a Module-Start Routine
In order to debug a kext's module-start routine, you must use the
-interactive (-i) or -interactive-all (-I) option, which pause after
loading and before calling the module-start function, so that you can set
up your debugging session as needed before proceeding.
FILES
/System/Library/Extensions/ The standard system repository of kernel
extensions.
/Library/Extensions/ The standard repository of non Apple kernel
extensions.
/System/Library/Caches/com.apple.kext.caches/*
Contains all kext caches for a Mac OS X 10.6
(Snow Leopard) system: prelinked kernel,
mkext, and system kext info caches.
/mach_kernel The default kernel file.
DIAGNOSTICS
kextutil exits with a zero status upon success. Upon failure, it prints
an error message and continues processing remaining kexts if possible,
then exits with a nonzero status.
For a kext to be loadable, it must be valid, authentic, have all depen-
dencies met (that is, all dependencies must be found and loadable). A
valid kext has a well formed bundle, info dictionary, and executable. An
authentic kext's component files are owned by root:wheel, with permis-
sions nonwritable by group and other. If your kext fails to load, try
using the -print-diagnostics (-t) option to print diagnostics related to
validation and authentication.
BUGS
Many single-letter options are inconsistent in meaning with (or directly
contradictory to) the same letter options in other kext tools.
SEE ALSO
kextcache(8), kextd(8), kextload(8), kextstat(8), kextunload(8),
kext_logging(8)
Darwin November 14, 2012 Darwin
Mac OS X 10.9 - Generated Fri Oct 18 05:36:22 CDT 2013