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| Current File : //sys/amd64/compile/hs32/modules/usr/src/sys/modules/re/@/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c |
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
* Portions Copyright 2010 The FreeBSD Foundation
*
* $FreeBSD: release/9.1.0/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c 212494 2010-09-12 14:12:16Z rpaulo $
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#if defined(sun)
#pragma ident "%Z%%M% %I% %E% SMI"
#endif
#include <sys/atomic.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <sys/modctl.h>
#include <sys/conf.h>
#include <sys/systm.h>
#if defined(sun)
#include <sys/ddi.h>
#endif
#include <sys/sunddi.h>
#include <sys/cpuvar.h>
#include <sys/kmem.h>
#if defined(sun)
#include <sys/strsubr.h>
#endif
#include <sys/fasttrap.h>
#include <sys/fasttrap_impl.h>
#include <sys/fasttrap_isa.h>
#include <sys/dtrace.h>
#include <sys/dtrace_impl.h>
#include <sys/sysmacros.h>
#include <sys/proc.h>
#include <sys/policy.h>
#if defined(sun)
#include <util/qsort.h>
#endif
#include <sys/mutex.h>
#include <sys/kernel.h>
#if !defined(sun)
#include <sys/user.h>
#include <sys/dtrace_bsd.h>
#include <cddl/dev/dtrace/dtrace_cddl.h>
#endif
/*
* User-Land Trap-Based Tracing
* ----------------------------
*
* The fasttrap provider allows DTrace consumers to instrument any user-level
* instruction to gather data; this includes probes with semantic
* signifigance like entry and return as well as simple offsets into the
* function. While the specific techniques used are very ISA specific, the
* methodology is generalizable to any architecture.
*
*
* The General Methodology
* -----------------------
*
* With the primary goal of tracing every user-land instruction and the
* limitation that we can't trust user space so don't want to rely on much
* information there, we begin by replacing the instructions we want to trace
* with trap instructions. Each instruction we overwrite is saved into a hash
* table keyed by process ID and pc address. When we enter the kernel due to
* this trap instruction, we need the effects of the replaced instruction to
* appear to have occurred before we proceed with the user thread's
* execution.
*
* Each user level thread is represented by a ulwp_t structure which is
* always easily accessible through a register. The most basic way to produce
* the effects of the instruction we replaced is to copy that instruction out
* to a bit of scratch space reserved in the user thread's ulwp_t structure
* (a sort of kernel-private thread local storage), set the PC to that
* scratch space and single step. When we reenter the kernel after single
* stepping the instruction we must then adjust the PC to point to what would
* normally be the next instruction. Of course, special care must be taken
* for branches and jumps, but these represent such a small fraction of any
* instruction set that writing the code to emulate these in the kernel is
* not too difficult.
*
* Return probes may require several tracepoints to trace every return site,
* and, conversely, each tracepoint may activate several probes (the entry
* and offset 0 probes, for example). To solve this muliplexing problem,
* tracepoints contain lists of probes to activate and probes contain lists
* of tracepoints to enable. If a probe is activated, it adds its ID to
* existing tracepoints or creates new ones as necessary.
*
* Most probes are activated _before_ the instruction is executed, but return
* probes are activated _after_ the effects of the last instruction of the
* function are visible. Return probes must be fired _after_ we have
* single-stepped the instruction whereas all other probes are fired
* beforehand.
*
*
* Lock Ordering
* -------------
*
* The lock ordering below -- both internally and with respect to the DTrace
* framework -- is a little tricky and bears some explanation. Each provider
* has a lock (ftp_mtx) that protects its members including reference counts
* for enabled probes (ftp_rcount), consumers actively creating probes
* (ftp_ccount) and USDT consumers (ftp_mcount); all three prevent a provider
* from being freed. A provider is looked up by taking the bucket lock for the
* provider hash table, and is returned with its lock held. The provider lock
* may be taken in functions invoked by the DTrace framework, but may not be
* held while calling functions in the DTrace framework.
*
* To ensure consistency over multiple calls to the DTrace framework, the
* creation lock (ftp_cmtx) should be held. Naturally, the creation lock may
* not be taken when holding the provider lock as that would create a cyclic
* lock ordering. In situations where one would naturally take the provider
* lock and then the creation lock, we instead up a reference count to prevent
* the provider from disappearing, drop the provider lock, and acquire the
* creation lock.
*
* Briefly:
* bucket lock before provider lock
* DTrace before provider lock
* creation lock before DTrace
* never hold the provider lock and creation lock simultaneously
*/
static d_open_t fasttrap_open;
static d_ioctl_t fasttrap_ioctl;
static struct cdevsw fasttrap_cdevsw = {
.d_version = D_VERSION,
.d_open = fasttrap_open,
.d_ioctl = fasttrap_ioctl,
.d_name = "fasttrap",
};
static struct cdev *fasttrap_cdev;
static dtrace_meta_provider_id_t fasttrap_meta_id;
static struct callout fasttrap_timeout;
static struct mtx fasttrap_cleanup_mtx;
static uint_t fasttrap_cleanup_work;
/*
* Generation count on modifications to the global tracepoint lookup table.
*/
static volatile uint64_t fasttrap_mod_gen;
/*
* When the fasttrap provider is loaded, fasttrap_max is set to either
* FASTTRAP_MAX_DEFAULT or the value for fasttrap-max-probes in the
* fasttrap.conf file. Each time a probe is created, fasttrap_total is
* incremented by the number of tracepoints that may be associated with that
* probe; fasttrap_total is capped at fasttrap_max.
*/
#define FASTTRAP_MAX_DEFAULT 250000
static uint32_t fasttrap_max;
static uint32_t fasttrap_total;
#define FASTTRAP_TPOINTS_DEFAULT_SIZE 0x4000
#define FASTTRAP_PROVIDERS_DEFAULT_SIZE 0x100
#define FASTTRAP_PROCS_DEFAULT_SIZE 0x100
#define FASTTRAP_PID_NAME "pid"
fasttrap_hash_t fasttrap_tpoints;
static fasttrap_hash_t fasttrap_provs;
static fasttrap_hash_t fasttrap_procs;
static uint64_t fasttrap_pid_count; /* pid ref count */
static kmutex_t fasttrap_count_mtx; /* lock on ref count */
#define FASTTRAP_ENABLE_FAIL 1
#define FASTTRAP_ENABLE_PARTIAL 2
static int fasttrap_tracepoint_enable(proc_t *, fasttrap_probe_t *, uint_t);
static void fasttrap_tracepoint_disable(proc_t *, fasttrap_probe_t *, uint_t);
static fasttrap_provider_t *fasttrap_provider_lookup(pid_t, const char *,
const dtrace_pattr_t *);
static void fasttrap_provider_retire(pid_t, const char *, int);
static void fasttrap_provider_free(fasttrap_provider_t *);
static fasttrap_proc_t *fasttrap_proc_lookup(pid_t);
static void fasttrap_proc_release(fasttrap_proc_t *);
#define FASTTRAP_PROVS_INDEX(pid, name) \
((fasttrap_hash_str(name) + (pid)) & fasttrap_provs.fth_mask)
#define FASTTRAP_PROCS_INDEX(pid) ((pid) & fasttrap_procs.fth_mask)
#if !defined(sun)
static kmutex_t fasttrap_cpuc_pid_lock[MAXCPU];
#endif
static int
fasttrap_highbit(ulong_t i)
{
int h = 1;
if (i == 0)
return (0);
#ifdef _LP64
if (i & 0xffffffff00000000ul) {
h += 32; i >>= 32;
}
#endif
if (i & 0xffff0000) {
h += 16; i >>= 16;
}
if (i & 0xff00) {
h += 8; i >>= 8;
}
if (i & 0xf0) {
h += 4; i >>= 4;
}
if (i & 0xc) {
h += 2; i >>= 2;
}
if (i & 0x2) {
h += 1;
}
return (h);
}
static uint_t
fasttrap_hash_str(const char *p)
{
unsigned int g;
uint_t hval = 0;
while (*p) {
hval = (hval << 4) + *p++;
if ((g = (hval & 0xf0000000)) != 0)
hval ^= g >> 24;
hval &= ~g;
}
return (hval);
}
void
fasttrap_sigtrap(proc_t *p, kthread_t *t, uintptr_t pc)
{
#if defined(sun)
sigqueue_t *sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP);
sqp->sq_info.si_signo = SIGTRAP;
sqp->sq_info.si_code = TRAP_DTRACE;
sqp->sq_info.si_addr = (caddr_t)pc;
mutex_enter(&p->p_lock);
sigaddqa(p, t, sqp);
mutex_exit(&p->p_lock);
if (t != NULL)
aston(t);
#else
ksiginfo_t *ksi = kmem_zalloc(sizeof (ksiginfo_t), KM_SLEEP);
ksiginfo_init(ksi);
ksi->ksi_signo = SIGTRAP;
ksi->ksi_code = TRAP_DTRACE;
ksi->ksi_addr = (caddr_t)pc;
PROC_LOCK(p);
(void) tdksignal(t, SIGTRAP, ksi);
PROC_UNLOCK(p);
#endif
}
/*
* This function ensures that no threads are actively using the memory
* associated with probes that were formerly live.
*/
static void
fasttrap_mod_barrier(uint64_t gen)
{
int i;
if (gen < fasttrap_mod_gen)
return;
fasttrap_mod_gen++;
CPU_FOREACH(i) {
mutex_enter(&fasttrap_cpuc_pid_lock[i]);
mutex_exit(&fasttrap_cpuc_pid_lock[i]);
}
}
/*
* This is the timeout's callback for cleaning up the providers and their
* probes.
*/
/*ARGSUSED*/
static void
fasttrap_pid_cleanup_cb(void *data)
{
fasttrap_provider_t **fpp, *fp;
fasttrap_bucket_t *bucket;
dtrace_provider_id_t provid;
int i, later = 0;
static volatile int in = 0;
ASSERT(in == 0);
in = 1;
while (fasttrap_cleanup_work) {
fasttrap_cleanup_work = 0;
mtx_unlock(&fasttrap_cleanup_mtx);
later = 0;
/*
* Iterate over all the providers trying to remove the marked
* ones. If a provider is marked but not retired, we just
* have to take a crack at removing it -- it's no big deal if
* we can't.
*/
for (i = 0; i < fasttrap_provs.fth_nent; i++) {
bucket = &fasttrap_provs.fth_table[i];
mutex_enter(&bucket->ftb_mtx);
fpp = (fasttrap_provider_t **)&bucket->ftb_data;
while ((fp = *fpp) != NULL) {
if (!fp->ftp_marked) {
fpp = &fp->ftp_next;
continue;
}
mutex_enter(&fp->ftp_mtx);
/*
* If this provider has consumers actively
* creating probes (ftp_ccount) or is a USDT
* provider (ftp_mcount), we can't unregister
* or even condense.
*/
if (fp->ftp_ccount != 0 ||
fp->ftp_mcount != 0) {
mutex_exit(&fp->ftp_mtx);
fp->ftp_marked = 0;
continue;
}
if (!fp->ftp_retired || fp->ftp_rcount != 0)
fp->ftp_marked = 0;
mutex_exit(&fp->ftp_mtx);
/*
* If we successfully unregister this
* provider we can remove it from the hash
* chain and free the memory. If our attempt
* to unregister fails and this is a retired
* provider, increment our flag to try again
* pretty soon. If we've consumed more than
* half of our total permitted number of
* probes call dtrace_condense() to try to
* clean out the unenabled probes.
*/
provid = fp->ftp_provid;
if (dtrace_unregister(provid) != 0) {
if (fasttrap_total > fasttrap_max / 2)
(void) dtrace_condense(provid);
later += fp->ftp_marked;
fpp = &fp->ftp_next;
} else {
*fpp = fp->ftp_next;
fasttrap_provider_free(fp);
}
}
mutex_exit(&bucket->ftb_mtx);
}
mtx_lock(&fasttrap_cleanup_mtx);
}
#if 0
ASSERT(fasttrap_timeout != 0);
#endif
/*
* If we were unable to remove a retired provider, try again after
* a second. This situation can occur in certain circumstances where
* providers cannot be unregistered even though they have no probes
* enabled because of an execution of dtrace -l or something similar.
* If the timeout has been disabled (set to 1 because we're trying
* to detach), we set fasttrap_cleanup_work to ensure that we'll
* get a chance to do that work if and when the timeout is reenabled
* (if detach fails).
*/
if (later > 0 && callout_active(&fasttrap_timeout))
callout_reset(&fasttrap_timeout, hz, &fasttrap_pid_cleanup_cb,
NULL);
else if (later > 0)
fasttrap_cleanup_work = 1;
else {
#if !defined(sun)
/* Nothing to be done for FreeBSD */
#endif
}
in = 0;
}
/*
* Activates the asynchronous cleanup mechanism.
*/
static void
fasttrap_pid_cleanup(void)
{
mtx_lock(&fasttrap_cleanup_mtx);
fasttrap_cleanup_work = 1;
callout_reset(&fasttrap_timeout, 1, &fasttrap_pid_cleanup_cb, NULL);
mtx_unlock(&fasttrap_cleanup_mtx);
}
/*
* This is called from cfork() via dtrace_fasttrap_fork(). The child
* process's address space is (roughly) a copy of the parent process's so
* we have to remove all the instrumentation we had previously enabled in the
* parent.
*/
static void
fasttrap_fork(proc_t *p, proc_t *cp)
{
pid_t ppid = p->p_pid;
int i;
#if defined(sun)
ASSERT(curproc == p);
ASSERT(p->p_proc_flag & P_PR_LOCK);
#else
PROC_LOCK_ASSERT(p, MA_OWNED);
#endif
#if defined(sun)
ASSERT(p->p_dtrace_count > 0);
#else
if (p->p_dtrace_helpers) {
/*
* dtrace_helpers_duplicate() allocates memory.
*/
_PHOLD(cp);
PROC_UNLOCK(p);
PROC_UNLOCK(cp);
dtrace_helpers_duplicate(p, cp);
PROC_LOCK(cp);
PROC_LOCK(p);
_PRELE(cp);
}
/*
* This check is purposely here instead of in kern_fork.c because,
* for legal resons, we cannot include the dtrace_cddl.h header
* inside kern_fork.c and insert if-clause there.
*/
if (p->p_dtrace_count == 0)
return;
#endif
ASSERT(cp->p_dtrace_count == 0);
/*
* This would be simpler and faster if we maintained per-process
* hash tables of enabled tracepoints. It could, however, potentially
* slow down execution of a tracepoint since we'd need to go
* through two levels of indirection. In the future, we should
* consider either maintaining per-process ancillary lists of
* enabled tracepoints or hanging a pointer to a per-process hash
* table of enabled tracepoints off the proc structure.
*/
/*
* We don't have to worry about the child process disappearing
* because we're in fork().
*/
#if defined(sun)
mtx_lock_spin(&cp->p_slock);
sprlock_proc(cp);
mtx_unlock_spin(&cp->p_slock);
#else
_PHOLD(cp);
#endif
/*
* Iterate over every tracepoint looking for ones that belong to the
* parent process, and remove each from the child process.
*/
for (i = 0; i < fasttrap_tpoints.fth_nent; i++) {
fasttrap_tracepoint_t *tp;
fasttrap_bucket_t *bucket = &fasttrap_tpoints.fth_table[i];
mutex_enter(&bucket->ftb_mtx);
for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
if (tp->ftt_pid == ppid &&
tp->ftt_proc->ftpc_acount != 0) {
int ret = fasttrap_tracepoint_remove(cp, tp);
ASSERT(ret == 0);
/*
* The count of active providers can only be
* decremented (i.e. to zero) during exec,
* exit, and removal of a meta provider so it
* should be impossible to drop the count
* mid-fork.
*/
ASSERT(tp->ftt_proc->ftpc_acount != 0);
}
}
mutex_exit(&bucket->ftb_mtx);
}
#if defined(sun)
mutex_enter(&cp->p_lock);
sprunlock(cp);
#else
_PRELE(cp);
#endif
}
/*
* This is called from proc_exit() or from exec_common() if p_dtrace_probes
* is set on the proc structure to indicate that there is a pid provider
* associated with this process.
*/
static void
fasttrap_exec_exit(proc_t *p)
{
#if defined(sun)
ASSERT(p == curproc);
#endif
PROC_LOCK_ASSERT(p, MA_OWNED);
_PHOLD(p);
PROC_UNLOCK(p);
/*
* We clean up the pid provider for this process here; user-land
* static probes are handled by the meta-provider remove entry point.
*/
fasttrap_provider_retire(p->p_pid, FASTTRAP_PID_NAME, 0);
#if !defined(sun)
if (p->p_dtrace_helpers)
dtrace_helpers_destroy(p);
#endif
PROC_LOCK(p);
_PRELE(p);
}
/*ARGSUSED*/
static void
fasttrap_pid_provide(void *arg, dtrace_probedesc_t *desc)
{
/*
* There are no "default" pid probes.
*/
}
static int
fasttrap_tracepoint_enable(proc_t *p, fasttrap_probe_t *probe, uint_t index)
{
fasttrap_tracepoint_t *tp, *new_tp = NULL;
fasttrap_bucket_t *bucket;
fasttrap_id_t *id;
pid_t pid;
uintptr_t pc;
ASSERT(index < probe->ftp_ntps);
pid = probe->ftp_pid;
pc = probe->ftp_tps[index].fit_tp->ftt_pc;
id = &probe->ftp_tps[index].fit_id;
ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid);
#if defined(sun)
ASSERT(!(p->p_flag & SVFORK));
#endif
/*
* Before we make any modifications, make sure we've imposed a barrier
* on the generation in which this probe was last modified.
*/
fasttrap_mod_barrier(probe->ftp_gen);
bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
/*
* If the tracepoint has already been enabled, just add our id to the
* list of interested probes. This may be our second time through
* this path in which case we'll have constructed the tracepoint we'd
* like to install. If we can't find a match, and have an allocated
* tracepoint ready to go, enable that one now.
*
* A tracepoint whose process is defunct is also considered defunct.
*/
again:
mutex_enter(&bucket->ftb_mtx);
for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
/*
* Note that it's safe to access the active count on the
* associated proc structure because we know that at least one
* provider (this one) will still be around throughout this
* operation.
*/
if (tp->ftt_pid != pid || tp->ftt_pc != pc ||
tp->ftt_proc->ftpc_acount == 0)
continue;
/*
* Now that we've found a matching tracepoint, it would be
* a decent idea to confirm that the tracepoint is still
* enabled and the trap instruction hasn't been overwritten.
* Since this is a little hairy, we'll punt for now.
*/
/*
* This can't be the first interested probe. We don't have
* to worry about another thread being in the midst of
* deleting this tracepoint (which would be the only valid
* reason for a tracepoint to have no interested probes)
* since we're holding P_PR_LOCK for this process.
*/
ASSERT(tp->ftt_ids != NULL || tp->ftt_retids != NULL);
switch (id->fti_ptype) {
case DTFTP_ENTRY:
case DTFTP_OFFSETS:
case DTFTP_IS_ENABLED:
id->fti_next = tp->ftt_ids;
membar_producer();
tp->ftt_ids = id;
membar_producer();
break;
case DTFTP_RETURN:
case DTFTP_POST_OFFSETS:
id->fti_next = tp->ftt_retids;
membar_producer();
tp->ftt_retids = id;
membar_producer();
break;
default:
ASSERT(0);
}
mutex_exit(&bucket->ftb_mtx);
if (new_tp != NULL) {
new_tp->ftt_ids = NULL;
new_tp->ftt_retids = NULL;
}
return (0);
}
/*
* If we have a good tracepoint ready to go, install it now while
* we have the lock held and no one can screw with us.
*/
if (new_tp != NULL) {
int rc = 0;
new_tp->ftt_next = bucket->ftb_data;
membar_producer();
bucket->ftb_data = new_tp;
membar_producer();
mutex_exit(&bucket->ftb_mtx);
/*
* Activate the tracepoint in the ISA-specific manner.
* If this fails, we need to report the failure, but
* indicate that this tracepoint must still be disabled
* by calling fasttrap_tracepoint_disable().
*/
if (fasttrap_tracepoint_install(p, new_tp) != 0)
rc = FASTTRAP_ENABLE_PARTIAL;
/*
* Increment the count of the number of tracepoints active in
* the victim process.
*/
#if defined(sun)
ASSERT(p->p_proc_flag & P_PR_LOCK);
#endif
p->p_dtrace_count++;
return (rc);
}
mutex_exit(&bucket->ftb_mtx);
/*
* Initialize the tracepoint that's been preallocated with the probe.
*/
new_tp = probe->ftp_tps[index].fit_tp;
ASSERT(new_tp->ftt_pid == pid);
ASSERT(new_tp->ftt_pc == pc);
ASSERT(new_tp->ftt_proc == probe->ftp_prov->ftp_proc);
ASSERT(new_tp->ftt_ids == NULL);
ASSERT(new_tp->ftt_retids == NULL);
switch (id->fti_ptype) {
case DTFTP_ENTRY:
case DTFTP_OFFSETS:
case DTFTP_IS_ENABLED:
id->fti_next = NULL;
new_tp->ftt_ids = id;
break;
case DTFTP_RETURN:
case DTFTP_POST_OFFSETS:
id->fti_next = NULL;
new_tp->ftt_retids = id;
break;
default:
ASSERT(0);
}
/*
* If the ISA-dependent initialization goes to plan, go back to the
* beginning and try to install this freshly made tracepoint.
*/
if (fasttrap_tracepoint_init(p, new_tp, pc, id->fti_ptype) == 0)
goto again;
new_tp->ftt_ids = NULL;
new_tp->ftt_retids = NULL;
return (FASTTRAP_ENABLE_FAIL);
}
static void
fasttrap_tracepoint_disable(proc_t *p, fasttrap_probe_t *probe, uint_t index)
{
fasttrap_bucket_t *bucket;
fasttrap_provider_t *provider = probe->ftp_prov;
fasttrap_tracepoint_t **pp, *tp;
fasttrap_id_t *id, **idp = NULL;
pid_t pid;
uintptr_t pc;
ASSERT(index < probe->ftp_ntps);
pid = probe->ftp_pid;
pc = probe->ftp_tps[index].fit_tp->ftt_pc;
id = &probe->ftp_tps[index].fit_id;
ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid);
/*
* Find the tracepoint and make sure that our id is one of the
* ones registered with it.
*/
bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
mutex_enter(&bucket->ftb_mtx);
for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
if (tp->ftt_pid == pid && tp->ftt_pc == pc &&
tp->ftt_proc == provider->ftp_proc)
break;
}
/*
* If we somehow lost this tracepoint, we're in a world of hurt.
*/
ASSERT(tp != NULL);
switch (id->fti_ptype) {
case DTFTP_ENTRY:
case DTFTP_OFFSETS:
case DTFTP_IS_ENABLED:
ASSERT(tp->ftt_ids != NULL);
idp = &tp->ftt_ids;
break;
case DTFTP_RETURN:
case DTFTP_POST_OFFSETS:
ASSERT(tp->ftt_retids != NULL);
idp = &tp->ftt_retids;
break;
default:
ASSERT(0);
}
while ((*idp)->fti_probe != probe) {
idp = &(*idp)->fti_next;
ASSERT(*idp != NULL);
}
id = *idp;
*idp = id->fti_next;
membar_producer();
ASSERT(id->fti_probe == probe);
/*
* If there are other registered enablings of this tracepoint, we're
* all done, but if this was the last probe assocated with this
* this tracepoint, we need to remove and free it.
*/
if (tp->ftt_ids != NULL || tp->ftt_retids != NULL) {
/*
* If the current probe's tracepoint is in use, swap it
* for an unused tracepoint.
*/
if (tp == probe->ftp_tps[index].fit_tp) {
fasttrap_probe_t *tmp_probe;
fasttrap_tracepoint_t **tmp_tp;
uint_t tmp_index;
if (tp->ftt_ids != NULL) {
tmp_probe = tp->ftt_ids->fti_probe;
/* LINTED - alignment */
tmp_index = FASTTRAP_ID_INDEX(tp->ftt_ids);
tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp;
} else {
tmp_probe = tp->ftt_retids->fti_probe;
/* LINTED - alignment */
tmp_index = FASTTRAP_ID_INDEX(tp->ftt_retids);
tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp;
}
ASSERT(*tmp_tp != NULL);
ASSERT(*tmp_tp != probe->ftp_tps[index].fit_tp);
ASSERT((*tmp_tp)->ftt_ids == NULL);
ASSERT((*tmp_tp)->ftt_retids == NULL);
probe->ftp_tps[index].fit_tp = *tmp_tp;
*tmp_tp = tp;
}
mutex_exit(&bucket->ftb_mtx);
/*
* Tag the modified probe with the generation in which it was
* changed.
*/
probe->ftp_gen = fasttrap_mod_gen;
return;
}
mutex_exit(&bucket->ftb_mtx);
/*
* We can't safely remove the tracepoint from the set of active
* tracepoints until we've actually removed the fasttrap instruction
* from the process's text. We can, however, operate on this
* tracepoint secure in the knowledge that no other thread is going to
* be looking at it since we hold P_PR_LOCK on the process if it's
* live or we hold the provider lock on the process if it's dead and
* gone.
*/
/*
* We only need to remove the actual instruction if we're looking
* at an existing process
*/
if (p != NULL) {
/*
* If we fail to restore the instruction we need to kill
* this process since it's in a completely unrecoverable
* state.
*/
if (fasttrap_tracepoint_remove(p, tp) != 0)
fasttrap_sigtrap(p, NULL, pc);
/*
* Decrement the count of the number of tracepoints active
* in the victim process.
*/
#if defined(sun)
ASSERT(p->p_proc_flag & P_PR_LOCK);
#endif
p->p_dtrace_count--;
}
/*
* Remove the probe from the hash table of active tracepoints.
*/
mutex_enter(&bucket->ftb_mtx);
pp = (fasttrap_tracepoint_t **)&bucket->ftb_data;
ASSERT(*pp != NULL);
while (*pp != tp) {
pp = &(*pp)->ftt_next;
ASSERT(*pp != NULL);
}
*pp = tp->ftt_next;
membar_producer();
mutex_exit(&bucket->ftb_mtx);
/*
* Tag the modified probe with the generation in which it was changed.
*/
probe->ftp_gen = fasttrap_mod_gen;
}
static void
fasttrap_enable_callbacks(void)
{
/*
* We don't have to play the rw lock game here because we're
* providing something rather than taking something away --
* we can be sure that no threads have tried to follow this
* function pointer yet.
*/
mutex_enter(&fasttrap_count_mtx);
if (fasttrap_pid_count == 0) {
ASSERT(dtrace_pid_probe_ptr == NULL);
ASSERT(dtrace_return_probe_ptr == NULL);
dtrace_pid_probe_ptr = &fasttrap_pid_probe;
dtrace_return_probe_ptr = &fasttrap_return_probe;
}
ASSERT(dtrace_pid_probe_ptr == &fasttrap_pid_probe);
ASSERT(dtrace_return_probe_ptr == &fasttrap_return_probe);
fasttrap_pid_count++;
mutex_exit(&fasttrap_count_mtx);
}
static void
fasttrap_disable_callbacks(void)
{
#if defined(sun)
ASSERT(MUTEX_HELD(&cpu_lock));
#endif
mutex_enter(&fasttrap_count_mtx);
ASSERT(fasttrap_pid_count > 0);
fasttrap_pid_count--;
if (fasttrap_pid_count == 0) {
#if defined(sun)
cpu_t *cur, *cpu = CPU;
for (cur = cpu->cpu_next_onln; cur != cpu;
cur = cur->cpu_next_onln) {
rw_enter(&cur->cpu_ft_lock, RW_WRITER);
}
#endif
dtrace_pid_probe_ptr = NULL;
dtrace_return_probe_ptr = NULL;
#if defined(sun)
for (cur = cpu->cpu_next_onln; cur != cpu;
cur = cur->cpu_next_onln) {
rw_exit(&cur->cpu_ft_lock);
}
#endif
}
mutex_exit(&fasttrap_count_mtx);
}
/*ARGSUSED*/
static void
fasttrap_pid_enable(void *arg, dtrace_id_t id, void *parg)
{
fasttrap_probe_t *probe = parg;
proc_t *p = NULL;
int i, rc;
ASSERT(probe != NULL);
ASSERT(!probe->ftp_enabled);
ASSERT(id == probe->ftp_id);
#if defined(sun)
ASSERT(MUTEX_HELD(&cpu_lock));
#endif
/*
* Increment the count of enabled probes on this probe's provider;
* the provider can't go away while the probe still exists. We
* must increment this even if we aren't able to properly enable
* this probe.
*/
mutex_enter(&probe->ftp_prov->ftp_mtx);
probe->ftp_prov->ftp_rcount++;
mutex_exit(&probe->ftp_prov->ftp_mtx);
/*
* If this probe's provider is retired (meaning it was valid in a
* previously exec'ed incarnation of this address space), bail out. The
* provider can't go away while we're in this code path.
*/
if (probe->ftp_prov->ftp_retired)
return;
/*
* If we can't find the process, it may be that we're in the context of
* a fork in which the traced process is being born and we're copying
* USDT probes. Otherwise, the process is gone so bail.
*/
#if defined(sun)
if ((p = sprlock(probe->ftp_pid)) == NULL) {
if ((curproc->p_flag & SFORKING) == 0)
return;
mutex_enter(&pidlock);
p = prfind(probe->ftp_pid);
/*
* Confirm that curproc is indeed forking the process in which
* we're trying to enable probes.
*/
ASSERT(p != NULL);
ASSERT(p->p_parent == curproc);
ASSERT(p->p_stat == SIDL);
mutex_enter(&p->p_lock);
mutex_exit(&pidlock);
sprlock_proc(p);
}
ASSERT(!(p->p_flag & SVFORK));
mutex_exit(&p->p_lock);
#else
if ((p = pfind(probe->ftp_pid)) == NULL)
return;
#endif
/*
* We have to enable the trap entry point before any user threads have
* the chance to execute the trap instruction we're about to place
* in their process's text.
*/
#ifdef __FreeBSD__
/*
* pfind() returns a locked process.
*/
_PHOLD(p);
PROC_UNLOCK(p);
#endif
fasttrap_enable_callbacks();
/*
* Enable all the tracepoints and add this probe's id to each
* tracepoint's list of active probes.
*/
for (i = 0; i < probe->ftp_ntps; i++) {
if ((rc = fasttrap_tracepoint_enable(p, probe, i)) != 0) {
/*
* If enabling the tracepoint failed completely,
* we don't have to disable it; if the failure
* was only partial we must disable it.
*/
if (rc == FASTTRAP_ENABLE_FAIL)
i--;
else
ASSERT(rc == FASTTRAP_ENABLE_PARTIAL);
/*
* Back up and pull out all the tracepoints we've
* created so far for this probe.
*/
while (i >= 0) {
fasttrap_tracepoint_disable(p, probe, i);
i--;
}
#if defined(sun)
mutex_enter(&p->p_lock);
sprunlock(p);
#else
PRELE(p);
#endif
/*
* Since we're not actually enabling this probe,
* drop our reference on the trap table entry.
*/
fasttrap_disable_callbacks();
return;
}
}
#if defined(sun)
mutex_enter(&p->p_lock);
sprunlock(p);
#else
PRELE(p);
#endif
probe->ftp_enabled = 1;
}
/*ARGSUSED*/
static void
fasttrap_pid_disable(void *arg, dtrace_id_t id, void *parg)
{
fasttrap_probe_t *probe = parg;
fasttrap_provider_t *provider = probe->ftp_prov;
proc_t *p;
int i, whack = 0;
ASSERT(id == probe->ftp_id);
mutex_enter(&provider->ftp_mtx);
/*
* We won't be able to acquire a /proc-esque lock on the process
* iff the process is dead and gone. In this case, we rely on the
* provider lock as a point of mutual exclusion to prevent other
* DTrace consumers from disabling this probe.
*/
if ((p = pfind(probe->ftp_pid)) == NULL) {
mutex_exit(&provider->ftp_mtx);
return;
}
#ifdef __FreeBSD__
_PHOLD(p);
PROC_UNLOCK(p);
#endif
/*
* Disable all the associated tracepoints (for fully enabled probes).
*/
if (probe->ftp_enabled) {
for (i = 0; i < probe->ftp_ntps; i++) {
fasttrap_tracepoint_disable(p, probe, i);
}
}
ASSERT(provider->ftp_rcount > 0);
provider->ftp_rcount--;
if (p != NULL) {
/*
* Even though we may not be able to remove it entirely, we
* mark this retired provider to get a chance to remove some
* of the associated probes.
*/
if (provider->ftp_retired && !provider->ftp_marked)
whack = provider->ftp_marked = 1;
mutex_exit(&provider->ftp_mtx);
} else {
/*
* If the process is dead, we're just waiting for the
* last probe to be disabled to be able to free it.
*/
if (provider->ftp_rcount == 0 && !provider->ftp_marked)
whack = provider->ftp_marked = 1;
mutex_exit(&provider->ftp_mtx);
}
if (whack)
fasttrap_pid_cleanup();
#ifdef __FreeBSD__
PRELE(p);
#endif
if (!probe->ftp_enabled)
return;
probe->ftp_enabled = 0;
#if defined(sun)
ASSERT(MUTEX_HELD(&cpu_lock));
#endif
fasttrap_disable_callbacks();
}
/*ARGSUSED*/
static void
fasttrap_pid_getargdesc(void *arg, dtrace_id_t id, void *parg,
dtrace_argdesc_t *desc)
{
fasttrap_probe_t *probe = parg;
char *str;
int i, ndx;
desc->dtargd_native[0] = '\0';
desc->dtargd_xlate[0] = '\0';
if (probe->ftp_prov->ftp_retired != 0 ||
desc->dtargd_ndx >= probe->ftp_nargs) {
desc->dtargd_ndx = DTRACE_ARGNONE;
return;
}
ndx = (probe->ftp_argmap != NULL) ?
probe->ftp_argmap[desc->dtargd_ndx] : desc->dtargd_ndx;
str = probe->ftp_ntypes;
for (i = 0; i < ndx; i++) {
str += strlen(str) + 1;
}
ASSERT(strlen(str + 1) < sizeof (desc->dtargd_native));
(void) strcpy(desc->dtargd_native, str);
if (probe->ftp_xtypes == NULL)
return;
str = probe->ftp_xtypes;
for (i = 0; i < desc->dtargd_ndx; i++) {
str += strlen(str) + 1;
}
ASSERT(strlen(str + 1) < sizeof (desc->dtargd_xlate));
(void) strcpy(desc->dtargd_xlate, str);
}
/*ARGSUSED*/
static void
fasttrap_pid_destroy(void *arg, dtrace_id_t id, void *parg)
{
fasttrap_probe_t *probe = parg;
int i;
size_t size;
ASSERT(probe != NULL);
ASSERT(!probe->ftp_enabled);
ASSERT(fasttrap_total >= probe->ftp_ntps);
atomic_add_32(&fasttrap_total, -probe->ftp_ntps);
size = offsetof(fasttrap_probe_t, ftp_tps[probe->ftp_ntps]);
if (probe->ftp_gen + 1 >= fasttrap_mod_gen)
fasttrap_mod_barrier(probe->ftp_gen);
for (i = 0; i < probe->ftp_ntps; i++) {
kmem_free(probe->ftp_tps[i].fit_tp,
sizeof (fasttrap_tracepoint_t));
}
kmem_free(probe, size);
}
static const dtrace_pattr_t pid_attr = {
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
};
static dtrace_pops_t pid_pops = {
fasttrap_pid_provide,
NULL,
fasttrap_pid_enable,
fasttrap_pid_disable,
NULL,
NULL,
fasttrap_pid_getargdesc,
fasttrap_pid_getarg,
NULL,
fasttrap_pid_destroy
};
static dtrace_pops_t usdt_pops = {
fasttrap_pid_provide,
NULL,
fasttrap_pid_enable,
fasttrap_pid_disable,
NULL,
NULL,
fasttrap_pid_getargdesc,
fasttrap_usdt_getarg,
NULL,
fasttrap_pid_destroy
};
static fasttrap_proc_t *
fasttrap_proc_lookup(pid_t pid)
{
fasttrap_bucket_t *bucket;
fasttrap_proc_t *fprc, *new_fprc;
bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
mutex_enter(&bucket->ftb_mtx);
for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) {
mutex_enter(&fprc->ftpc_mtx);
mutex_exit(&bucket->ftb_mtx);
fprc->ftpc_rcount++;
atomic_add_64(&fprc->ftpc_acount, 1);
ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount);
mutex_exit(&fprc->ftpc_mtx);
return (fprc);
}
}
/*
* Drop the bucket lock so we don't try to perform a sleeping
* allocation under it.
*/
mutex_exit(&bucket->ftb_mtx);
new_fprc = kmem_zalloc(sizeof (fasttrap_proc_t), KM_SLEEP);
new_fprc->ftpc_pid = pid;
new_fprc->ftpc_rcount = 1;
new_fprc->ftpc_acount = 1;
#if !defined(sun)
mutex_init(&new_fprc->ftpc_mtx, "fasttrap proc mtx", MUTEX_DEFAULT,
NULL);
#endif
mutex_enter(&bucket->ftb_mtx);
/*
* Take another lap through the list to make sure a proc hasn't
* been created for this pid while we weren't under the bucket lock.
*/
for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) {
mutex_enter(&fprc->ftpc_mtx);
mutex_exit(&bucket->ftb_mtx);
fprc->ftpc_rcount++;
atomic_add_64(&fprc->ftpc_acount, 1);
ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount);
mutex_exit(&fprc->ftpc_mtx);
kmem_free(new_fprc, sizeof (fasttrap_proc_t));
return (fprc);
}
}
new_fprc->ftpc_next = bucket->ftb_data;
bucket->ftb_data = new_fprc;
mutex_exit(&bucket->ftb_mtx);
return (new_fprc);
}
static void
fasttrap_proc_release(fasttrap_proc_t *proc)
{
fasttrap_bucket_t *bucket;
fasttrap_proc_t *fprc, **fprcp;
pid_t pid = proc->ftpc_pid;
mutex_enter(&proc->ftpc_mtx);
ASSERT(proc->ftpc_rcount != 0);
ASSERT(proc->ftpc_acount <= proc->ftpc_rcount);
if (--proc->ftpc_rcount != 0) {
mutex_exit(&proc->ftpc_mtx);
return;
}
mutex_exit(&proc->ftpc_mtx);
/*
* There should definitely be no live providers associated with this
* process at this point.
*/
ASSERT(proc->ftpc_acount == 0);
bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
mutex_enter(&bucket->ftb_mtx);
fprcp = (fasttrap_proc_t **)&bucket->ftb_data;
while ((fprc = *fprcp) != NULL) {
if (fprc == proc)
break;
fprcp = &fprc->ftpc_next;
}
/*
* Something strange has happened if we can't find the proc.
*/
ASSERT(fprc != NULL);
*fprcp = fprc->ftpc_next;
mutex_exit(&bucket->ftb_mtx);
kmem_free(fprc, sizeof (fasttrap_proc_t));
}
/*
* Lookup a fasttrap-managed provider based on its name and associated pid.
* If the pattr argument is non-NULL, this function instantiates the provider
* if it doesn't exist otherwise it returns NULL. The provider is returned
* with its lock held.
*/
static fasttrap_provider_t *
fasttrap_provider_lookup(pid_t pid, const char *name,
const dtrace_pattr_t *pattr)
{
fasttrap_provider_t *fp, *new_fp = NULL;
fasttrap_bucket_t *bucket;
char provname[DTRACE_PROVNAMELEN];
proc_t *p;
cred_t *cred;
ASSERT(strlen(name) < sizeof (fp->ftp_name));
ASSERT(pattr != NULL);
bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)];
mutex_enter(&bucket->ftb_mtx);
/*
* Take a lap through the list and return the match if we find it.
*/
for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
!fp->ftp_retired) {
mutex_enter(&fp->ftp_mtx);
mutex_exit(&bucket->ftb_mtx);
return (fp);
}
}
/*
* Drop the bucket lock so we don't try to perform a sleeping
* allocation under it.
*/
mutex_exit(&bucket->ftb_mtx);
/*
* Make sure the process exists, isn't a child created as the result
* of a vfork(2), and isn't a zombie (but may be in fork).
*/
if ((p = pfind(pid)) == NULL)
return (NULL);
/*
* Increment p_dtrace_probes so that the process knows to inform us
* when it exits or execs. fasttrap_provider_free() decrements this
* when we're done with this provider.
*/
p->p_dtrace_probes++;
/*
* Grab the credentials for this process so we have
* something to pass to dtrace_register().
*/
PROC_LOCK_ASSERT(p, MA_OWNED);
crhold(p->p_ucred);
cred = p->p_ucred;
PROC_UNLOCK(p);
new_fp = kmem_zalloc(sizeof (fasttrap_provider_t), KM_SLEEP);
new_fp->ftp_pid = pid;
new_fp->ftp_proc = fasttrap_proc_lookup(pid);
#if !defined(sun)
mutex_init(&new_fp->ftp_mtx, "provider mtx", MUTEX_DEFAULT, NULL);
mutex_init(&new_fp->ftp_cmtx, "lock on creating", MUTEX_DEFAULT, NULL);
#endif
ASSERT(new_fp->ftp_proc != NULL);
mutex_enter(&bucket->ftb_mtx);
/*
* Take another lap through the list to make sure a provider hasn't
* been created for this pid while we weren't under the bucket lock.
*/
for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
!fp->ftp_retired) {
mutex_enter(&fp->ftp_mtx);
mutex_exit(&bucket->ftb_mtx);
fasttrap_provider_free(new_fp);
crfree(cred);
return (fp);
}
}
(void) strcpy(new_fp->ftp_name, name);
/*
* Fail and return NULL if either the provider name is too long
* or we fail to register this new provider with the DTrace
* framework. Note that this is the only place we ever construct
* the full provider name -- we keep it in pieces in the provider
* structure.
*/
if (snprintf(provname, sizeof (provname), "%s%u", name, (uint_t)pid) >=
sizeof (provname) ||
dtrace_register(provname, pattr,
DTRACE_PRIV_PROC | DTRACE_PRIV_OWNER | DTRACE_PRIV_ZONEOWNER, cred,
pattr == &pid_attr ? &pid_pops : &usdt_pops, new_fp,
&new_fp->ftp_provid) != 0) {
mutex_exit(&bucket->ftb_mtx);
fasttrap_provider_free(new_fp);
crfree(cred);
return (NULL);
}
new_fp->ftp_next = bucket->ftb_data;
bucket->ftb_data = new_fp;
mutex_enter(&new_fp->ftp_mtx);
mutex_exit(&bucket->ftb_mtx);
crfree(cred);
return (new_fp);
}
static void
fasttrap_provider_free(fasttrap_provider_t *provider)
{
pid_t pid = provider->ftp_pid;
proc_t *p;
/*
* There need to be no associated enabled probes, no consumers
* creating probes, and no meta providers referencing this provider.
*/
ASSERT(provider->ftp_rcount == 0);
ASSERT(provider->ftp_ccount == 0);
ASSERT(provider->ftp_mcount == 0);
/*
* If this provider hasn't been retired, we need to explicitly drop the
* count of active providers on the associated process structure.
*/
if (!provider->ftp_retired) {
atomic_add_64(&provider->ftp_proc->ftpc_acount, -1);
ASSERT(provider->ftp_proc->ftpc_acount <
provider->ftp_proc->ftpc_rcount);
}
fasttrap_proc_release(provider->ftp_proc);
#if !defined(sun)
mutex_destroy(&provider->ftp_mtx);
mutex_destroy(&provider->ftp_cmtx);
#endif
kmem_free(provider, sizeof (fasttrap_provider_t));
/*
* Decrement p_dtrace_probes on the process whose provider we're
* freeing. We don't have to worry about clobbering somone else's
* modifications to it because we have locked the bucket that
* corresponds to this process's hash chain in the provider hash
* table. Don't sweat it if we can't find the process.
*/
if ((p = pfind(pid)) == NULL) {
return;
}
p->p_dtrace_probes--;
#if !defined(sun)
PROC_UNLOCK(p);
#endif
}
static void
fasttrap_provider_retire(pid_t pid, const char *name, int mprov)
{
fasttrap_provider_t *fp;
fasttrap_bucket_t *bucket;
dtrace_provider_id_t provid;
ASSERT(strlen(name) < sizeof (fp->ftp_name));
bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)];
mutex_enter(&bucket->ftb_mtx);
for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
!fp->ftp_retired)
break;
}
if (fp == NULL) {
mutex_exit(&bucket->ftb_mtx);
return;
}
mutex_enter(&fp->ftp_mtx);
ASSERT(!mprov || fp->ftp_mcount > 0);
if (mprov && --fp->ftp_mcount != 0) {
mutex_exit(&fp->ftp_mtx);
mutex_exit(&bucket->ftb_mtx);
return;
}
/*
* Mark the provider to be removed in our post-processing step, mark it
* retired, and drop the active count on its proc. Marking it indicates
* that we should try to remove it; setting the retired flag indicates
* that we're done with this provider; dropping the active the proc
* releases our hold, and when this reaches zero (as it will during
* exit or exec) the proc and associated providers become defunct.
*
* We obviously need to take the bucket lock before the provider lock
* to perform the lookup, but we need to drop the provider lock
* before calling into the DTrace framework since we acquire the
* provider lock in callbacks invoked from the DTrace framework. The
* bucket lock therefore protects the integrity of the provider hash
* table.
*/
atomic_add_64(&fp->ftp_proc->ftpc_acount, -1);
ASSERT(fp->ftp_proc->ftpc_acount < fp->ftp_proc->ftpc_rcount);
fp->ftp_retired = 1;
fp->ftp_marked = 1;
provid = fp->ftp_provid;
mutex_exit(&fp->ftp_mtx);
/*
* We don't have to worry about invalidating the same provider twice
* since fasttrap_provider_lookup() will ignore provider that have
* been marked as retired.
*/
dtrace_invalidate(provid);
mutex_exit(&bucket->ftb_mtx);
fasttrap_pid_cleanup();
}
static int
fasttrap_uint32_cmp(const void *ap, const void *bp)
{
return (*(const uint32_t *)ap - *(const uint32_t *)bp);
}
static int
fasttrap_uint64_cmp(const void *ap, const void *bp)
{
return (*(const uint64_t *)ap - *(const uint64_t *)bp);
}
static int
fasttrap_add_probe(fasttrap_probe_spec_t *pdata)
{
fasttrap_provider_t *provider;
fasttrap_probe_t *pp;
fasttrap_tracepoint_t *tp;
char *name;
int i, aframes = 0, whack;
/*
* There needs to be at least one desired trace point.
*/
if (pdata->ftps_noffs == 0)
return (EINVAL);
switch (pdata->ftps_type) {
case DTFTP_ENTRY:
name = "entry";
aframes = FASTTRAP_ENTRY_AFRAMES;
break;
case DTFTP_RETURN:
name = "return";
aframes = FASTTRAP_RETURN_AFRAMES;
break;
case DTFTP_OFFSETS:
name = NULL;
break;
default:
return (EINVAL);
}
if ((provider = fasttrap_provider_lookup(pdata->ftps_pid,
FASTTRAP_PID_NAME, &pid_attr)) == NULL)
return (ESRCH);
/*
* Increment this reference count to indicate that a consumer is
* actively adding a new probe associated with this provider. This
* prevents the provider from being deleted -- we'll need to check
* for pending deletions when we drop this reference count.
*/
provider->ftp_ccount++;
mutex_exit(&provider->ftp_mtx);
/*
* Grab the creation lock to ensure consistency between calls to
* dtrace_probe_lookup() and dtrace_probe_create() in the face of
* other threads creating probes. We must drop the provider lock
* before taking this lock to avoid a three-way deadlock with the
* DTrace framework.
*/
mutex_enter(&provider->ftp_cmtx);
if (name == NULL) {
for (i = 0; i < pdata->ftps_noffs; i++) {
char name_str[17];
(void) sprintf(name_str, "%llx",
(unsigned long long)pdata->ftps_offs[i]);
if (dtrace_probe_lookup(provider->ftp_provid,
pdata->ftps_mod, pdata->ftps_func, name_str) != 0)
continue;
atomic_add_32(&fasttrap_total, 1);
if (fasttrap_total > fasttrap_max) {
atomic_add_32(&fasttrap_total, -1);
goto no_mem;
}
pp = kmem_zalloc(sizeof (fasttrap_probe_t), KM_SLEEP);
pp->ftp_prov = provider;
pp->ftp_faddr = pdata->ftps_pc;
pp->ftp_fsize = pdata->ftps_size;
pp->ftp_pid = pdata->ftps_pid;
pp->ftp_ntps = 1;
tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t),
KM_SLEEP);
tp->ftt_proc = provider->ftp_proc;
tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc;
tp->ftt_pid = pdata->ftps_pid;
pp->ftp_tps[0].fit_tp = tp;
pp->ftp_tps[0].fit_id.fti_probe = pp;
pp->ftp_tps[0].fit_id.fti_ptype = pdata->ftps_type;
pp->ftp_id = dtrace_probe_create(provider->ftp_provid,
pdata->ftps_mod, pdata->ftps_func, name_str,
FASTTRAP_OFFSET_AFRAMES, pp);
}
} else if (dtrace_probe_lookup(provider->ftp_provid, pdata->ftps_mod,
pdata->ftps_func, name) == 0) {
atomic_add_32(&fasttrap_total, pdata->ftps_noffs);
if (fasttrap_total > fasttrap_max) {
atomic_add_32(&fasttrap_total, -pdata->ftps_noffs);
goto no_mem;
}
/*
* Make sure all tracepoint program counter values are unique.
* We later assume that each probe has exactly one tracepoint
* for a given pc.
*/
qsort(pdata->ftps_offs, pdata->ftps_noffs,
sizeof (uint64_t), fasttrap_uint64_cmp);
for (i = 1; i < pdata->ftps_noffs; i++) {
if (pdata->ftps_offs[i] > pdata->ftps_offs[i - 1])
continue;
atomic_add_32(&fasttrap_total, -pdata->ftps_noffs);
goto no_mem;
}
ASSERT(pdata->ftps_noffs > 0);
pp = kmem_zalloc(offsetof(fasttrap_probe_t,
ftp_tps[pdata->ftps_noffs]), KM_SLEEP);
pp->ftp_prov = provider;
pp->ftp_faddr = pdata->ftps_pc;
pp->ftp_fsize = pdata->ftps_size;
pp->ftp_pid = pdata->ftps_pid;
pp->ftp_ntps = pdata->ftps_noffs;
for (i = 0; i < pdata->ftps_noffs; i++) {
tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t),
KM_SLEEP);
tp->ftt_proc = provider->ftp_proc;
tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc;
tp->ftt_pid = pdata->ftps_pid;
pp->ftp_tps[i].fit_tp = tp;
pp->ftp_tps[i].fit_id.fti_probe = pp;
pp->ftp_tps[i].fit_id.fti_ptype = pdata->ftps_type;
}
pp->ftp_id = dtrace_probe_create(provider->ftp_provid,
pdata->ftps_mod, pdata->ftps_func, name, aframes, pp);
}
mutex_exit(&provider->ftp_cmtx);
/*
* We know that the provider is still valid since we incremented the
* creation reference count. If someone tried to clean up this provider
* while we were using it (e.g. because the process called exec(2) or
* exit(2)), take note of that and try to clean it up now.
*/
mutex_enter(&provider->ftp_mtx);
provider->ftp_ccount--;
whack = provider->ftp_retired;
mutex_exit(&provider->ftp_mtx);
if (whack)
fasttrap_pid_cleanup();
return (0);
no_mem:
/*
* If we've exhausted the allowable resources, we'll try to remove
* this provider to free some up. This is to cover the case where
* the user has accidentally created many more probes than was
* intended (e.g. pid123:::).
*/
mutex_exit(&provider->ftp_cmtx);
mutex_enter(&provider->ftp_mtx);
provider->ftp_ccount--;
provider->ftp_marked = 1;
mutex_exit(&provider->ftp_mtx);
fasttrap_pid_cleanup();
return (ENOMEM);
}
/*ARGSUSED*/
static void *
fasttrap_meta_provide(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
{
fasttrap_provider_t *provider;
/*
* A 32-bit unsigned integer (like a pid for example) can be
* expressed in 10 or fewer decimal digits. Make sure that we'll
* have enough space for the provider name.
*/
if (strlen(dhpv->dthpv_provname) + 10 >=
sizeof (provider->ftp_name)) {
printf("failed to instantiate provider %s: "
"name too long to accomodate pid", dhpv->dthpv_provname);
return (NULL);
}
/*
* Don't let folks spoof the true pid provider.
*/
if (strcmp(dhpv->dthpv_provname, FASTTRAP_PID_NAME) == 0) {
printf("failed to instantiate provider %s: "
"%s is an invalid name", dhpv->dthpv_provname,
FASTTRAP_PID_NAME);
return (NULL);
}
/*
* The highest stability class that fasttrap supports is ISA; cap
* the stability of the new provider accordingly.
*/
if (dhpv->dthpv_pattr.dtpa_provider.dtat_class > DTRACE_CLASS_ISA)
dhpv->dthpv_pattr.dtpa_provider.dtat_class = DTRACE_CLASS_ISA;
if (dhpv->dthpv_pattr.dtpa_mod.dtat_class > DTRACE_CLASS_ISA)
dhpv->dthpv_pattr.dtpa_mod.dtat_class = DTRACE_CLASS_ISA;
if (dhpv->dthpv_pattr.dtpa_func.dtat_class > DTRACE_CLASS_ISA)
dhpv->dthpv_pattr.dtpa_func.dtat_class = DTRACE_CLASS_ISA;
if (dhpv->dthpv_pattr.dtpa_name.dtat_class > DTRACE_CLASS_ISA)
dhpv->dthpv_pattr.dtpa_name.dtat_class = DTRACE_CLASS_ISA;
if (dhpv->dthpv_pattr.dtpa_args.dtat_class > DTRACE_CLASS_ISA)
dhpv->dthpv_pattr.dtpa_args.dtat_class = DTRACE_CLASS_ISA;
if ((provider = fasttrap_provider_lookup(pid, dhpv->dthpv_provname,
&dhpv->dthpv_pattr)) == NULL) {
printf("failed to instantiate provider %s for "
"process %u", dhpv->dthpv_provname, (uint_t)pid);
return (NULL);
}
/*
* Up the meta provider count so this provider isn't removed until
* the meta provider has been told to remove it.
*/
provider->ftp_mcount++;
mutex_exit(&provider->ftp_mtx);
return (provider);
}
/*ARGSUSED*/
static void
fasttrap_meta_create_probe(void *arg, void *parg,
dtrace_helper_probedesc_t *dhpb)
{
fasttrap_provider_t *provider = parg;
fasttrap_probe_t *pp;
fasttrap_tracepoint_t *tp;
int i, j;
uint32_t ntps;
/*
* Since the meta provider count is non-zero we don't have to worry
* about this provider disappearing.
*/
ASSERT(provider->ftp_mcount > 0);
/*
* The offsets must be unique.
*/
qsort(dhpb->dthpb_offs, dhpb->dthpb_noffs, sizeof (uint32_t),
fasttrap_uint32_cmp);
for (i = 1; i < dhpb->dthpb_noffs; i++) {
if (dhpb->dthpb_base + dhpb->dthpb_offs[i] <=
dhpb->dthpb_base + dhpb->dthpb_offs[i - 1])
return;
}
qsort(dhpb->dthpb_enoffs, dhpb->dthpb_nenoffs, sizeof (uint32_t),
fasttrap_uint32_cmp);
for (i = 1; i < dhpb->dthpb_nenoffs; i++) {
if (dhpb->dthpb_base + dhpb->dthpb_enoffs[i] <=
dhpb->dthpb_base + dhpb->dthpb_enoffs[i - 1])
return;
}
/*
* Grab the creation lock to ensure consistency between calls to
* dtrace_probe_lookup() and dtrace_probe_create() in the face of
* other threads creating probes.
*/
mutex_enter(&provider->ftp_cmtx);
if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod,
dhpb->dthpb_func, dhpb->dthpb_name) != 0) {
mutex_exit(&provider->ftp_cmtx);
return;
}
ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs;
ASSERT(ntps > 0);
atomic_add_32(&fasttrap_total, ntps);
if (fasttrap_total > fasttrap_max) {
atomic_add_32(&fasttrap_total, -ntps);
mutex_exit(&provider->ftp_cmtx);
return;
}
pp = kmem_zalloc(offsetof(fasttrap_probe_t, ftp_tps[ntps]), KM_SLEEP);
pp->ftp_prov = provider;
pp->ftp_pid = provider->ftp_pid;
pp->ftp_ntps = ntps;
pp->ftp_nargs = dhpb->dthpb_xargc;
pp->ftp_xtypes = dhpb->dthpb_xtypes;
pp->ftp_ntypes = dhpb->dthpb_ntypes;
/*
* First create a tracepoint for each actual point of interest.
*/
for (i = 0; i < dhpb->dthpb_noffs; i++) {
tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP);
tp->ftt_proc = provider->ftp_proc;
tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_offs[i];
tp->ftt_pid = provider->ftp_pid;
pp->ftp_tps[i].fit_tp = tp;
pp->ftp_tps[i].fit_id.fti_probe = pp;
#ifdef __sparc
pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_POST_OFFSETS;
#else
pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_OFFSETS;
#endif
}
/*
* Then create a tracepoint for each is-enabled point.
*/
for (j = 0; i < ntps; i++, j++) {
tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP);
tp->ftt_proc = provider->ftp_proc;
tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_enoffs[j];
tp->ftt_pid = provider->ftp_pid;
pp->ftp_tps[i].fit_tp = tp;
pp->ftp_tps[i].fit_id.fti_probe = pp;
pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_IS_ENABLED;
}
/*
* If the arguments are shuffled around we set the argument remapping
* table. Later, when the probe fires, we only remap the arguments
* if the table is non-NULL.
*/
for (i = 0; i < dhpb->dthpb_xargc; i++) {
if (dhpb->dthpb_args[i] != i) {
pp->ftp_argmap = dhpb->dthpb_args;
break;
}
}
/*
* The probe is fully constructed -- register it with DTrace.
*/
pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod,
dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp);
mutex_exit(&provider->ftp_cmtx);
}
/*ARGSUSED*/
static void
fasttrap_meta_remove(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
{
/*
* Clean up the USDT provider. There may be active consumers of the
* provider busy adding probes, no damage will actually befall the
* provider until that count has dropped to zero. This just puts
* the provider on death row.
*/
fasttrap_provider_retire(pid, dhpv->dthpv_provname, 1);
}
static dtrace_mops_t fasttrap_mops = {
fasttrap_meta_create_probe,
fasttrap_meta_provide,
fasttrap_meta_remove
};
/*ARGSUSED*/
static int
fasttrap_open(struct cdev *dev __unused, int oflags __unused,
int devtype __unused, struct thread *td __unused)
{
return (0);
}
/*ARGSUSED*/
static int
fasttrap_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int fflag,
struct thread *td)
{
#ifdef notyet
struct kinfo_proc kp;
const cred_t *cr = td->td_ucred;
#endif
if (!dtrace_attached())
return (EAGAIN);
if (cmd == FASTTRAPIOC_MAKEPROBE) {
fasttrap_probe_spec_t *uprobe = (void *)arg;
fasttrap_probe_spec_t *probe;
uint64_t noffs;
size_t size;
int ret;
char *c;
#if defined(sun)
if (copyin(&uprobe->ftps_noffs, &noffs,
sizeof (uprobe->ftps_noffs)))
return (EFAULT);
#else
noffs = uprobe->ftps_noffs;
#endif
/*
* Probes must have at least one tracepoint.
*/
if (noffs == 0)
return (EINVAL);
size = sizeof (fasttrap_probe_spec_t) +
sizeof (probe->ftps_offs[0]) * (noffs - 1);
if (size > 1024 * 1024)
return (ENOMEM);
probe = kmem_alloc(size, KM_SLEEP);
#if defined(sun)
if (copyin(uprobe, probe, size) != 0) {
kmem_free(probe, size);
return (EFAULT);
}
#else
memcpy(probe, uprobe, sizeof(*probe));
if (noffs > 1 && copyin(uprobe + 1, probe + 1, size) != 0) {
kmem_free(probe, size);
return (EFAULT);
}
#endif
/*
* Verify that the function and module strings contain no
* funny characters.
*/
for (c = &probe->ftps_func[0]; *c != '\0'; c++) {
if (*c < 0x20 || 0x7f <= *c) {
ret = EINVAL;
goto err;
}
}
for (c = &probe->ftps_mod[0]; *c != '\0'; c++) {
if (*c < 0x20 || 0x7f <= *c) {
ret = EINVAL;
goto err;
}
}
#ifdef notyet
if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {
proc_t *p;
pid_t pid = probe->ftps_pid;
#if defined(sun)
mutex_enter(&pidlock);
#endif
/*
* Report an error if the process doesn't exist
* or is actively being birthed.
*/
p = pfind(pid);
if (p)
fill_kinfo_proc(p, &kp);
if (p == NULL || kp.ki_stat == SIDL) {
#if defined(sun)
mutex_exit(&pidlock);
#endif
return (ESRCH);
}
#if defined(sun)
mutex_enter(&p->p_lock);
mutex_exit(&pidlock);
#else
PROC_LOCK_ASSERT(p, MA_OWNED);
#endif
#ifdef notyet
if ((ret = priv_proc_cred_perm(cr, p, NULL,
VREAD | VWRITE)) != 0) {
#if defined(sun)
mutex_exit(&p->p_lock);
#else
PROC_UNLOCK(p);
#endif
return (ret);
}
#endif /* notyet */
#if defined(sun)
mutex_exit(&p->p_lock);
#else
PROC_UNLOCK(p);
#endif
}
#endif /* notyet */
ret = fasttrap_add_probe(probe);
err:
kmem_free(probe, size);
return (ret);
} else if (cmd == FASTTRAPIOC_GETINSTR) {
fasttrap_instr_query_t instr;
fasttrap_tracepoint_t *tp;
uint_t index;
#if defined(sun)
int ret;
#endif
#if defined(sun)
if (copyin((void *)arg, &instr, sizeof (instr)) != 0)
return (EFAULT);
#endif
#ifdef notyet
if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {
proc_t *p;
pid_t pid = instr.ftiq_pid;
#if defined(sun)
mutex_enter(&pidlock);
#endif
/*
* Report an error if the process doesn't exist
* or is actively being birthed.
*/
p = pfind(pid);
if (p)
fill_kinfo_proc(p, &kp);
if (p == NULL || kp.ki_stat == SIDL) {
#if defined(sun)
mutex_exit(&pidlock);
#endif
return (ESRCH);
}
#if defined(sun)
mutex_enter(&p->p_lock);
mutex_exit(&pidlock);
#else
PROC_LOCK_ASSERT(p, MA_OWNED);
#endif
#ifdef notyet
if ((ret = priv_proc_cred_perm(cr, p, NULL,
VREAD)) != 0) {
#if defined(sun)
mutex_exit(&p->p_lock);
#else
PROC_UNLOCK(p);
#endif
return (ret);
}
#endif /* notyet */
#if defined(sun)
mutex_exit(&p->p_lock);
#else
PROC_UNLOCK(p);
#endif
}
#endif /* notyet */
index = FASTTRAP_TPOINTS_INDEX(instr.ftiq_pid, instr.ftiq_pc);
mutex_enter(&fasttrap_tpoints.fth_table[index].ftb_mtx);
tp = fasttrap_tpoints.fth_table[index].ftb_data;
while (tp != NULL) {
if (instr.ftiq_pid == tp->ftt_pid &&
instr.ftiq_pc == tp->ftt_pc &&
tp->ftt_proc->ftpc_acount != 0)
break;
tp = tp->ftt_next;
}
if (tp == NULL) {
mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx);
return (ENOENT);
}
bcopy(&tp->ftt_instr, &instr.ftiq_instr,
sizeof (instr.ftiq_instr));
mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx);
if (copyout(&instr, (void *)arg, sizeof (instr)) != 0)
return (EFAULT);
return (0);
}
return (EINVAL);
}
static int
fasttrap_load(void)
{
ulong_t nent;
int i;
/* Create the /dev/dtrace/fasttrap entry. */
fasttrap_cdev = make_dev(&fasttrap_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
"dtrace/fasttrap");
mtx_init(&fasttrap_cleanup_mtx, "fasttrap clean", "dtrace", MTX_DEF);
callout_init_mtx(&fasttrap_timeout, &fasttrap_cleanup_mtx, 0);
mutex_init(&fasttrap_count_mtx, "fasttrap count mtx", MUTEX_DEFAULT,
NULL);
/*
* Install our hooks into fork(2), exec(2), and exit(2).
*/
dtrace_fasttrap_fork = &fasttrap_fork;
dtrace_fasttrap_exit = &fasttrap_exec_exit;
dtrace_fasttrap_exec = &fasttrap_exec_exit;
#if defined(sun)
fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
"fasttrap-max-probes", FASTTRAP_MAX_DEFAULT);
#else
fasttrap_max = FASTTRAP_MAX_DEFAULT;
#endif
fasttrap_total = 0;
/*
* Conjure up the tracepoints hashtable...
*/
#if defined(sun)
nent = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
"fasttrap-hash-size", FASTTRAP_TPOINTS_DEFAULT_SIZE);
#else
nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
#endif
if (nent == 0 || nent > 0x1000000)
nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
if ((nent & (nent - 1)) == 0)
fasttrap_tpoints.fth_nent = nent;
else
fasttrap_tpoints.fth_nent = 1 << fasttrap_highbit(nent);
ASSERT(fasttrap_tpoints.fth_nent > 0);
fasttrap_tpoints.fth_mask = fasttrap_tpoints.fth_nent - 1;
fasttrap_tpoints.fth_table = kmem_zalloc(fasttrap_tpoints.fth_nent *
sizeof (fasttrap_bucket_t), KM_SLEEP);
#if !defined(sun)
for (i = 0; i < fasttrap_tpoints.fth_nent; i++)
mutex_init(&fasttrap_tpoints.fth_table[i].ftb_mtx,
"tracepoints bucket mtx", MUTEX_DEFAULT, NULL);
#endif
/*
* ... and the providers hash table...
*/
nent = FASTTRAP_PROVIDERS_DEFAULT_SIZE;
if ((nent & (nent - 1)) == 0)
fasttrap_provs.fth_nent = nent;
else
fasttrap_provs.fth_nent = 1 << fasttrap_highbit(nent);
ASSERT(fasttrap_provs.fth_nent > 0);
fasttrap_provs.fth_mask = fasttrap_provs.fth_nent - 1;
fasttrap_provs.fth_table = kmem_zalloc(fasttrap_provs.fth_nent *
sizeof (fasttrap_bucket_t), KM_SLEEP);
#if !defined(sun)
for (i = 0; i < fasttrap_provs.fth_nent; i++)
mutex_init(&fasttrap_provs.fth_table[i].ftb_mtx,
"providers bucket mtx", MUTEX_DEFAULT, NULL);
#endif
/*
* ... and the procs hash table.
*/
nent = FASTTRAP_PROCS_DEFAULT_SIZE;
if ((nent & (nent - 1)) == 0)
fasttrap_procs.fth_nent = nent;
else
fasttrap_procs.fth_nent = 1 << fasttrap_highbit(nent);
ASSERT(fasttrap_procs.fth_nent > 0);
fasttrap_procs.fth_mask = fasttrap_procs.fth_nent - 1;
fasttrap_procs.fth_table = kmem_zalloc(fasttrap_procs.fth_nent *
sizeof (fasttrap_bucket_t), KM_SLEEP);
#if !defined(sun)
for (i = 0; i < fasttrap_procs.fth_nent; i++)
mutex_init(&fasttrap_procs.fth_table[i].ftb_mtx,
"processes bucket mtx", MUTEX_DEFAULT, NULL);
CPU_FOREACH(i) {
mutex_init(&fasttrap_cpuc_pid_lock[i], "fasttrap barrier",
MUTEX_DEFAULT, NULL);
}
#endif
(void) dtrace_meta_register("fasttrap", &fasttrap_mops, NULL,
&fasttrap_meta_id);
return (0);
}
static int
fasttrap_unload(void)
{
int i, fail = 0;
/*
* Unregister the meta-provider to make sure no new fasttrap-
* managed providers come along while we're trying to close up
* shop. If we fail to detach, we'll need to re-register as a
* meta-provider. We can fail to unregister as a meta-provider
* if providers we manage still exist.
*/
if (fasttrap_meta_id != DTRACE_METAPROVNONE &&
dtrace_meta_unregister(fasttrap_meta_id) != 0)
return (-1);
/*
* Prevent any new timeouts from running by setting fasttrap_timeout
* to a non-zero value, and wait for the current timeout to complete.
*/
mtx_lock(&fasttrap_cleanup_mtx);
fasttrap_cleanup_work = 0;
callout_drain(&fasttrap_timeout);
mtx_unlock(&fasttrap_cleanup_mtx);
/*
* Iterate over all of our providers. If there's still a process
* that corresponds to that pid, fail to detach.
*/
for (i = 0; i < fasttrap_provs.fth_nent; i++) {
fasttrap_provider_t **fpp, *fp;
fasttrap_bucket_t *bucket = &fasttrap_provs.fth_table[i];
mutex_enter(&bucket->ftb_mtx);
fpp = (fasttrap_provider_t **)&bucket->ftb_data;
while ((fp = *fpp) != NULL) {
/*
* Acquire and release the lock as a simple way of
* waiting for any other consumer to finish with
* this provider. A thread must first acquire the
* bucket lock so there's no chance of another thread
* blocking on the provider's lock.
*/
mutex_enter(&fp->ftp_mtx);
mutex_exit(&fp->ftp_mtx);
if (dtrace_unregister(fp->ftp_provid) != 0) {
fail = 1;
fpp = &fp->ftp_next;
} else {
*fpp = fp->ftp_next;
fasttrap_provider_free(fp);
}
}
mutex_exit(&bucket->ftb_mtx);
}
if (fail) {
uint_t work;
/*
* If we're failing to detach, we need to unblock timeouts
* and start a new timeout if any work has accumulated while
* we've been unsuccessfully trying to detach.
*/
mtx_lock(&fasttrap_cleanup_mtx);
work = fasttrap_cleanup_work;
callout_drain(&fasttrap_timeout);
mtx_unlock(&fasttrap_cleanup_mtx);
if (work)
fasttrap_pid_cleanup();
(void) dtrace_meta_register("fasttrap", &fasttrap_mops, NULL,
&fasttrap_meta_id);
return (-1);
}
#ifdef DEBUG
mutex_enter(&fasttrap_count_mtx);
ASSERT(fasttrap_pid_count == 0);
mutex_exit(&fasttrap_count_mtx);
#endif
kmem_free(fasttrap_tpoints.fth_table,
fasttrap_tpoints.fth_nent * sizeof (fasttrap_bucket_t));
fasttrap_tpoints.fth_nent = 0;
kmem_free(fasttrap_provs.fth_table,
fasttrap_provs.fth_nent * sizeof (fasttrap_bucket_t));
fasttrap_provs.fth_nent = 0;
kmem_free(fasttrap_procs.fth_table,
fasttrap_procs.fth_nent * sizeof (fasttrap_bucket_t));
fasttrap_procs.fth_nent = 0;
/*
* We know there are no tracepoints in any process anywhere in
* the system so there is no process which has its p_dtrace_count
* greater than zero, therefore we know that no thread can actively
* be executing code in fasttrap_fork(). Similarly for p_dtrace_probes
* and fasttrap_exec() and fasttrap_exit().
*/
ASSERT(dtrace_fasttrap_fork == &fasttrap_fork);
dtrace_fasttrap_fork = NULL;
ASSERT(dtrace_fasttrap_exec == &fasttrap_exec_exit);
dtrace_fasttrap_exec = NULL;
ASSERT(dtrace_fasttrap_exit == &fasttrap_exec_exit);
dtrace_fasttrap_exit = NULL;
#if !defined(sun)
destroy_dev(fasttrap_cdev);
mutex_destroy(&fasttrap_count_mtx);
CPU_FOREACH(i) {
mutex_destroy(&fasttrap_cpuc_pid_lock[i]);
}
#endif
return (0);
}
/* ARGSUSED */
static int
fasttrap_modevent(module_t mod __unused, int type, void *data __unused)
{
int error = 0;
switch (type) {
case MOD_LOAD:
break;
case MOD_UNLOAD:
break;
case MOD_SHUTDOWN:
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
SYSINIT(fasttrap_load, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY, fasttrap_load,
NULL);
SYSUNINIT(fasttrap_unload, SI_SUB_DTRACE_PROVIDER, SI_ORDER_ANY,
fasttrap_unload, NULL);
DEV_MODULE(fasttrap, fasttrap_modevent, NULL);
MODULE_VERSION(fasttrap, 1);
MODULE_DEPEND(fasttrap, dtrace, 1, 1, 1);
MODULE_DEPEND(fasttrap, opensolaris, 1, 1, 1);