TNFCTL_PROBE_APPLY(3TNF) TNF Library Functions TNFCTL_PROBE_APPLY(3TNF)


NAME


tnfctl_probe_apply, tnfctl_probe_apply_ids - iterate over probes

SYNOPSIS


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

tnfctl_errcode_t tnfctl_probe_apply(tnfctl_handle_t *hndl,
tnfctl_probe_op_t probe_op, void *clientdata);


tnfctl_errcode_t tnfctl_probe_apply_ids(tnfctl_handle_t *hndl,
ulong_t probe_count, ulong_t *probe_ids,
tnfctl_probe_op_t probe_op, void *clientdata);


DESCRIPTION


tnfctl_probe_apply() is used to iterate over the probes controlled by
hndl. For every probe, the probe_op function is called:

typedef tnfctl_errcode_t (*tnfctl_probe_op_t)(
tnfctl_handle_t *hndl,
tnfctl_probe_t *probe_hndl,
void *clientdata);


Several predefined functions are available for use as probe_op. These
functions are described in tnfctl_probe_state_get(3TNF).


The clientdata supplied in tnfctl_probe_apply() is passed in as the last
argument of probe_op. The probe_hndl in the probe operation function can
be used to query or change the state of the probe. See
tnfctl_probe_state_get(3TNF). The probe_op function should return
TNFCTL_ERR_NONE upon success. It can also return an error code, which
will cause tnfctl_probe_apply() to stop processing the rest of the probes
and return with the same error code. Note that there are five (5) error
codes reserved that the client can use for its own semantics. See
ERRORS.


The lifetime of probe_hndl is the same as the lifetime of hndl. It is
good until hndl is closed by tnfctl_close(3TNF). Do not confuse a
probe_hndl with hndl. The probe_hndl refers to a particular probe, while
hndl refers to a process or the kernel. If probe_hndl is used in another
libtnfctl(3TNF) interface, and it references a probe in a library that
has been dynamically closed (see dlclose(3C)), then the error code
TNFCTL_ERR_INVALIDPROBE will be returned by that interface.


tnfctl_probe_apply_ids() is very similar to tnfctl_probe_apply(). The
difference is that probe_op is called only for probes that match a probe
id specified in the array of integers referenced by probe_ids. The number
of probe ids in the array should be specified in probe_count. Use
tnfctl_probe_state_get() to get the probe_id that corresponds to the
probe_handl.

RETURN VALUES


tnfctl_probe_apply() and tnfctl_probe_apply_ids() return TNFCTL_ERR_NONE
upon success.

ERRORS


The following errors apply to both tnfctl_probe_apply() and
tnfctl_probe_apply_ids():

TNFCTL_ERR_INTERNAL
An internal error occurred.


TNFCTL_ERR_USR1
Error code reserved for user.


TNFCTL_ERR_USR2
Error code reserved for user.


TNFCTL_ERR_USR3
Error code reserved for user.


TNFCTL_ERR_USR4
Error code reserved for user.


TNFCTL_ERR_USR5
Error code reserved for user.


tnfctl_probe_apply() and tnfctl_probe_apply_ids() also return any error
returned by the callback function probe_op.


The following errors apply only to tnfctl_probe_apply_ids():

TNFCTL_ERR_INVALIDPROBE
The probe handle is no longer valid. For
example, the probe is in a library that has
been closed by dlclose(3C).


EXAMPLES


Example 1: Enabling Probes




To enable all probes:


tnfctl_probe_apply(hndl, tnfctl_probe_enable, NULL);


Example 2: Disabling Probes




To disable the probes that match a certain pattern in the probe attribute
string:


/* To disable all probes that contain the string "vm" */
tnfctl_probe_apply(hndl, select_disable, "vm");
static tnfctl_errcode_t
select_disable(tnfctl_handle_t *hndl, tnfctl_probe_t *probe_hndl,
void *client_data)
{
char *pattern = client_data;
tnfctl_probe_state_t probe_state;
tnfctl_probe_state_get(hndl, probe_hndl, &probe_state);
if (strstr(probe_state.attr_string, pattern)) {
tnfctl_probe_disable(hndl, probe_hndl, NULL);
}
}


Note that these examples do not have any error handling code.


ATTRIBUTES


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


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

SEE ALSO


prex(1), TNF_PROBE(3TNF), dlclose(3C), dlopen(3C), libtnfctl(3TNF),
tnfctl_close(3TNF), tnfctl_probe_state_get(3TNF), tracing(3TNF),
tnf_kernel_probes(4), attributes(5)


Linker and Libraries Guide


March 1, 2004 TNFCTL_PROBE_APPLY(3TNF)