TNFCTL_PROBE_STATE_GET(3TNF) TNF Library Functions TNFCTL_PROBE_STATE_GET(3TNF)


NAME


tnfctl_probe_state_get, tnfctl_probe_enable, tnfctl_probe_disable,
tnfctl_probe_trace, tnfctl_probe_untrace, tnfctl_probe_connect,
tnfctl_probe_disconnect_all - interfaces to query and to change the state
of a probe

SYNOPSIS


cc [ flag ... ] file ... -ltnfctl [ library ... ]
#include <tnf/tnfctl.h>

tnfctl_errcode_t tnfctl_probe_state_get(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, tnfctl_probe_state_t *state);


tnfctl_errcode_t tnfctl_probe_enable(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, void *ignored);


tnfctl_errcode_t tnfctl_probe_disable(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, void *ignored);


tnfctl_errcode_t tnfctl_probe_trace(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, void *ignored);


tnfctl_errcode_t tnfctl_probe_untrace(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, void *ignored);


tnfctl_errcode_t tnfctl_probe_disconnect_all(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, void *ignored);


tnfctl_errcode_t tnfctl_probe_connect(tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl, const char *lib_base_name,
const char *func_name);


DESCRIPTION


tnfctl_probe_state_get() returns the state of the probe specified by
probe_hndl in the process or kernel specified by hndl. The user will pass
these in to an apply iterator. The caller must also allocate state and
pass in a pointer to it. The semantics of the individual members of
state are:

id
The unique integer assigned to this probe. This
number does not change over the lifetime of
this probe. A probe_hndl can be obtained by
using the calls tnfctl_apply(),
tanfctl_apply_ids(), or
tnfctl_register_funcs().


attr_string
A string that consists of attribute value
pairs separated by semicolons. For the syntax
of this string, see the syntax of the detail
argument of the TNF_PROBE(3TNF) macro. The
attributes name, slots, keys, file, and line
are defined for every probe. Additional user-
defined attributes can be added by using the
detail argument of the TNF_PROBE(3TNF) macro.
An example of attr_string follows:

"name pageout;slots vnode pages_pageout ;
keys vm pageio io;file vm.c;line 25;"


enabled
B_TRUE if the probe is enabled, or B_FALSE if
the probe is disabled. Probes are disabled by
default. Use tnfctl_probe_enable() or
tnfctl_probe_disable() to change this state.


traced
B_TRUE if the probe is traced, or B_FALSE if
the probe is not traced. Probes in user
processes are traced by default. Kernel probes
are untraced by default. Use
tnfctl_probe_trace() or tnfctl_probe_untrace()
to change this state.


new_probe
B_TRUE if this is a new probe brought in since
the last change in libraries. See dlopen(3C)
or dlclose(3C). Otherwise, the value of
new_probe will be B_FALSE. This field is not
meaningful for kernel probe control.


obj_name
The name of the shared object or executable in
which the probe is located. This string can
be freed, so the client should make a copy of
the string if it needs to be saved for use by
other libtnfctl interfaces. In kernel mode,
this string is always NULL.


func_names
A null-terminated array of pointers to strings
that contain the names of functions connected
to this probe. Whenever an enabled probe is
encountered at runtime, these functions are
executed. This array also will be freed by the
library when the state of the probe changes.
Use tnfctl_probe_connect() or
tnfctl_probe_disconnect_all() to change this
state.


func_addrs
A null-terminated array of pointers to
addresses of functions in the target image
connected to this probe. This array also will
be freed by the library when the state of the
probe changes.


client_registered_data
Data that was registered by the client for this
probe by the creator function in
tnfctl_register_funcs(3TNF).


tnfctl_probe_enable(), tnfctl_probe_disable(), tnfctl_probe_trace(),
tnfctl_probe_untrace(), and tnfctl_probe_disconnect_all() ignore the last
argument. This convenient feature permits these functions to be used in
the probe_op field of tnfctl_probe_apply(3TNF) and
tnfctl_probe_apply_ids(3TNF). tnfctl_probe_enable() enables the probe
specified by probe_hndl. This is the master switch on a probe. A probe
does not perform any action until it is enabled.


tnfctl_probe_disable() disables the probe specified by probe_hndl.


tnfctl_probe_trace() turns on tracing for the probe specified by
probe_hndl. Probes emit a trace record only if the probe is traced.


tnfctl_probe_untrace() turns off tracing for the probe specified by
probe_hndl. This is useful if you want to connect probe functions to a
probe without tracing it.


tnfctl_probe_connect() connects the function func_name which exists in
the library lib_base_name, to the probe specified by probe_hndl.
tnfctl_probe_connect() returns an error code if used on a kernel tnfctl
handle. lib_base_name is the base name (not a path) of the library. If
it is NULL, and multiple functions in the target process match
func_name, one of the matching functions is chosen arbitrarily. A probe
function is a function that is in the target's address space and is
written to a certain specification. The specification is not currently
published.


tnf_probe_debug() is one function exported by libtnfprobe.so.1 and is the
debug function that prex(1) uses. When the debug function is executed,
it prints out the probe arguments and the value of the sunw%debug
attribute of the probe to stderr.


tnfctl_probe_disconnect_all() disconnects all probe functions from the
probe specified by probe_hndl.


Note that no libtnfctl call returns a probe handle (tnfctl_probe_t), yet
each of the routines described here takes a probe_hndl as an argument.
These routines may be used by passing them to one of the
tnfctl_probe_apply(3TNF) iterators as the "op" argument. Alternatively,
probe handles may be obtained and saved by a user's "op" function, and
they can be passed later as the probe_hndl argument when using any of the
functions described here.

RETURN VALUES


tnfctl_probe_state_get(), tnfctl_probe_enable(), tnfctl_probe_disable(),
tnfctl_probe_trace(), tnfctl_probe_untrace(),
tnfctl_probe_disconnect_all() and tnfctl_probe_connect() return
TNFCTL_ERR_NONE upon success.

ERRORS


The following error codes apply to tnfctl_probe_state_get():

TNFCTL_ERR_INVALIDPROBE
probe_hndl is no longer valid. The library
that the probe was in could have been
dynamically closed by dlclose(3C).


The following error codes apply to tnfctl_probe_enable(),
tnfctl_probe_disable(), tnfctl_probe_trace(), tnfctl_probe_untrace(), and
tnfctl_probe_disconnect_all()

TNFCTL_ERR_INVALIDPROBE
probe_hndl is no longer valid. The library
that the probe was in could have been
dynamically closed by dlclose(3C).


TNFCTL_ERR_BUFBROKEN
Cannot do probe operations because tracing is
broken in the target.


TNFCTL_ERR_NOBUF
Cannot do probe operations until a buffer is
allocated. See tnfctl_buffer_alloc(3TNF). This
error code does not apply to kernel probe
control.


The following error codes apply to tnfctl_probe_connect():

TNFCTL_ERR_INVALIDPROBE
probe_hndl is no longer valid. The library
that the probe was in could have been
dynamically closed by dlclose(3C).


TNFCTL_ERR_BADARG
The handle is a kernel handle, or func_name
could not be found.


TNFCTL_ERR_BUFBROKEN
Cannot do probe operations because tracing is
broken in the target.


TNFCTL_ERR_NOBUF
Cannot do probe operations until a buffer is
allocated. See tnfctl_buffer_alloc(3TNF).


ATTRIBUTES


See attributes(5) for description of the following attributes:


+---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|MT Level | MT-Safe |
+---------------+-----------------+

SEE ALSO


prex(1), TNF_PROBE(3TNF), libtnfctl(3TNF), tnfctl_check_libs(3TNF),
tnfctl_continue(3TNF), tnfctl_probe_apply(3TNF),
tnfctl_probe_apply_ids(3TNF), tracing(3TNF), tnf_kernel_probes(4),
attributes(5)


March 1, 2004 TNFCTL_PROBE_STATE_GET(3TNF)