5572901b33
This is BSD licensed code written specifically for FreeBSD. It initialises using SYSINIT so that the SDT provider, probe and argument description linkage is done whenever a module is loaded, regardless of whether the DTrace modules are loaded or not. This file is optionally compiled into the kernel if the KDTRACE_HOOKS option is defined.
274 lines
6.1 KiB
C
274 lines
6.1 KiB
C
/*-
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* Copyright 2006-2008 John Birrell <jb@FreeBSD.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*
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* Backend for the Statically Defined Tracing (SDT) kernel support. This is
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* required to allow a module to load even though DTrace kernel support may
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* not be present. A module may be built with SDT probes in it which are
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* registered and deregistered via SYSINIT/SYSUNINIT.
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*
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*/
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#include "opt_kdtrace.h"
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#include <sys/cdefs.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/linker.h>
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#include <sys/lock.h>
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#include <sys/proc.h>
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#include <sys/sx.h>
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#include <sys/sdt.h>
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/*
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* This is the list of statically defined tracing providers.
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*/
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static TAILQ_HEAD(sdt_provider_list_head, sdt_provider) sdt_provider_list;
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/*
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* Mutex to serialise access to the SDT provider list.
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*/
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static struct sx sdt_sx;
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/*
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* Hook for the DTrace probe function. The 'sdt' provider will set this
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* to dtrace_probe when it loads.
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*/
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sdt_probe_func_t sdt_probe_func = sdt_probe_stub;
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/*
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* This is a stub for probe calls in case kernel DTrace support isn't
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* compiled in. It should never get called because there is no DTrace
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* support to enable it.
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*/
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void
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sdt_probe_stub(u_int32_t id, uintptr_t arg0, uintptr_t arg1,
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uintptr_t arg2, uintptr_t arg3, uintptr_t arg4)
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{
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printf("sdt_probe_stub: Why did this get called?\n");
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}
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/*
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* Called from SYSINIT to register a provider.
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*/
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void
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sdt_provider_register(void *arg)
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{
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struct sdt_provider *prov = arg;
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sx_xlock(&sdt_sx);
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TAILQ_INSERT_TAIL(&sdt_provider_list, prov, prov_entry);
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TAILQ_INIT(&prov->probe_list);
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sx_xunlock(&sdt_sx);
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}
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/*
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* Called from SYSUNINIT to de-register a provider.
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*/
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void
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sdt_provider_deregister(void *arg)
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{
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struct sdt_provider *prov = arg;
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sx_xlock(&sdt_sx);
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TAILQ_REMOVE(&sdt_provider_list, prov, prov_entry);
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sx_xunlock(&sdt_sx);
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}
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/*
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* Called from SYSINIT to register a statically defined trace probe.
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*/
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void
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sdt_probe_register(void *arg)
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{
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struct sdt_probe *probe = arg;
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/*
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* Check the reference structure version. Only version 1 is
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* supported at the moment.
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*/
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if (probe->version != sizeof(struct sdt_probe)) {
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printf("%s:%s:%s has version %d when %d required\n", probe->mod, probe->func, probe->name, probe->version, (int) sizeof(struct sdt_probe));
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return;
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}
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sx_xlock(&sdt_sx);
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TAILQ_INSERT_TAIL(&probe->prov->probe_list, probe, probe_entry);
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TAILQ_INIT(&probe->argtype_list);
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probe->state = SDT_INIT;
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sx_xunlock(&sdt_sx);
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}
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/*
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* Called from SYSUNINIT to de-register a statically defined trace probe.
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*/
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void
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sdt_probe_deregister(void *arg)
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{
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struct sdt_probe *probe = arg;
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sx_xlock(&sdt_sx);
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if (probe->state == SDT_INIT) {
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TAILQ_REMOVE(&probe->prov->probe_list, probe, probe_entry);
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probe->state = SDT_UNINIT;
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}
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sx_xunlock(&sdt_sx);
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}
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/*
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* Called from SYSINIT to register a statically defined trace probe argument.
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*/
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void
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sdt_argtype_register(void *arg)
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{
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struct sdt_argtype *argtype = arg;
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sx_xlock(&sdt_sx);
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TAILQ_INSERT_TAIL(&argtype->probe->argtype_list, argtype, argtype_entry);
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argtype->probe->n_args++;
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sx_xunlock(&sdt_sx);
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}
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/*
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* Called from SYSUNINIT to de-register a statically defined trace probe argument.
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*/
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void
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sdt_argtype_deregister(void *arg)
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{
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struct sdt_argtype *argtype = arg;
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sx_xlock(&sdt_sx);
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TAILQ_REMOVE(&argtype->probe->argtype_list, argtype, argtype_entry);
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sx_xunlock(&sdt_sx);
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}
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static void
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sdt_init(void *arg)
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{
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sx_init_flags(&sdt_sx, "Statically Defined Tracing", SX_NOWITNESS);
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TAILQ_INIT(&sdt_provider_list);
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}
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SYSINIT(sdt, SI_SUB_KDTRACE, SI_ORDER_FIRST, sdt_init, NULL);
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static void
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sdt_uninit(void *arg)
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{
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sx_destroy(&sdt_sx);
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}
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SYSUNINIT(sdt, SI_SUB_KDTRACE, SI_ORDER_FIRST, sdt_uninit, NULL);
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/*
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* List statically defined tracing providers.
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*/
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int
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sdt_provider_listall(sdt_provider_listall_func_t callback_func,void *arg)
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{
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int error = 0;
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struct sdt_provider *prov;
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sx_xlock(&sdt_sx);
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TAILQ_FOREACH(prov, &sdt_provider_list, prov_entry) {
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if ((error = callback_func(prov, arg)) != 0)
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break;
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}
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sx_xunlock(&sdt_sx);
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return (error);
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}
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/*
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* List statically defined tracing probes.
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*/
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int
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sdt_probe_listall(struct sdt_provider *prov,
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sdt_probe_listall_func_t callback_func,void *arg)
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{
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int error = 0;
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int locked;
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struct sdt_probe *probe;
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locked = sx_xlocked(&sdt_sx);
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if (!locked)
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sx_xlock(&sdt_sx);
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TAILQ_FOREACH(probe, &prov->probe_list, probe_entry) {
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if ((error = callback_func(probe, arg)) != 0)
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break;
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}
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if (!locked)
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sx_xunlock(&sdt_sx);
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return (error);
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}
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/*
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* List statically defined tracing probe arguments.
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*/
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int
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sdt_argtype_listall(struct sdt_probe *probe,
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sdt_argtype_listall_func_t callback_func,void *arg)
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{
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int error = 0;
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int locked;
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struct sdt_argtype *argtype;
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locked = sx_xlocked(&sdt_sx);
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if (!locked)
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sx_xlock(&sdt_sx);
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TAILQ_FOREACH(argtype, &probe->argtype_list, argtype_entry) {
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if ((error = callback_func(argtype, arg)) != 0)
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break;
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}
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if (!locked)
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sx_xunlock(&sdt_sx);
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return (error);
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}
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