24 */
25
26/*
27 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
28 * Use is subject to license terms.
29 */
30
31/*
32 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
33 */
34
35#include <sys/atomic.h>
36#include <sys/errno.h>
37#include <sys/stat.h>
38#include <sys/modctl.h>
39#include <sys/conf.h>
40#include <sys/systm.h>
41#if defined(sun)
42#include <sys/ddi.h>
43#endif
44#include <sys/sunddi.h>
45#include <sys/cpuvar.h>
46#include <sys/kmem.h>
47#if defined(sun)
48#include <sys/strsubr.h>
49#endif
50#include <sys/fasttrap.h>
51#include <sys/fasttrap_impl.h>
52#include <sys/fasttrap_isa.h>
53#include <sys/dtrace.h>
54#include <sys/dtrace_impl.h>
55#include <sys/sysmacros.h>
56#include <sys/proc.h>
57#include <sys/policy.h>
58#if defined(sun)
59#include <util/qsort.h>
60#endif
61#include <sys/mutex.h>
62#include <sys/kernel.h>
63#if !defined(sun)
64#include <sys/dtrace_bsd.h>
65#include <sys/eventhandler.h>
66#include <sys/u8_textprep.h>
67#include <sys/user.h>
68#include <vm/vm.h>
69#include <vm/pmap.h>
70#include <vm/vm_map.h>
71#include <vm/vm_param.h>
72#include <cddl/dev/dtrace/dtrace_cddl.h>
73#endif
74
75/*
76 * User-Land Trap-Based Tracing
77 * ----------------------------
78 *
79 * The fasttrap provider allows DTrace consumers to instrument any user-level
80 * instruction to gather data; this includes probes with semantic
81 * signifigance like entry and return as well as simple offsets into the
82 * function. While the specific techniques used are very ISA specific, the
83 * methodology is generalizable to any architecture.
84 *
85 *
86 * The General Methodology
87 * -----------------------
88 *
89 * With the primary goal of tracing every user-land instruction and the
90 * limitation that we can't trust user space so don't want to rely on much
91 * information there, we begin by replacing the instructions we want to trace
92 * with trap instructions. Each instruction we overwrite is saved into a hash
93 * table keyed by process ID and pc address. When we enter the kernel due to
94 * this trap instruction, we need the effects of the replaced instruction to
95 * appear to have occurred before we proceed with the user thread's
96 * execution.
97 *
98 * Each user level thread is represented by a ulwp_t structure which is
99 * always easily accessible through a register. The most basic way to produce
100 * the effects of the instruction we replaced is to copy that instruction out
101 * to a bit of scratch space reserved in the user thread's ulwp_t structure
102 * (a sort of kernel-private thread local storage), set the PC to that
103 * scratch space and single step. When we reenter the kernel after single
104 * stepping the instruction we must then adjust the PC to point to what would
105 * normally be the next instruction. Of course, special care must be taken
106 * for branches and jumps, but these represent such a small fraction of any
107 * instruction set that writing the code to emulate these in the kernel is
108 * not too difficult.
109 *
110 * Return probes may require several tracepoints to trace every return site,
111 * and, conversely, each tracepoint may activate several probes (the entry
112 * and offset 0 probes, for example). To solve this muliplexing problem,
113 * tracepoints contain lists of probes to activate and probes contain lists
114 * of tracepoints to enable. If a probe is activated, it adds its ID to
115 * existing tracepoints or creates new ones as necessary.
116 *
117 * Most probes are activated _before_ the instruction is executed, but return
118 * probes are activated _after_ the effects of the last instruction of the
119 * function are visible. Return probes must be fired _after_ we have
120 * single-stepped the instruction whereas all other probes are fired
121 * beforehand.
122 *
123 *
124 * Lock Ordering
125 * -------------
126 *
127 * The lock ordering below -- both internally and with respect to the DTrace
128 * framework -- is a little tricky and bears some explanation. Each provider
129 * has a lock (ftp_mtx) that protects its members including reference counts
130 * for enabled probes (ftp_rcount), consumers actively creating probes
131 * (ftp_ccount) and USDT consumers (ftp_mcount); all three prevent a provider
132 * from being freed. A provider is looked up by taking the bucket lock for the
133 * provider hash table, and is returned with its lock held. The provider lock
134 * may be taken in functions invoked by the DTrace framework, but may not be
135 * held while calling functions in the DTrace framework.
136 *
137 * To ensure consistency over multiple calls to the DTrace framework, the
138 * creation lock (ftp_cmtx) should be held. Naturally, the creation lock may
139 * not be taken when holding the provider lock as that would create a cyclic
140 * lock ordering. In situations where one would naturally take the provider
141 * lock and then the creation lock, we instead up a reference count to prevent
142 * the provider from disappearing, drop the provider lock, and acquire the
143 * creation lock.
144 *
145 * Briefly:
146 * bucket lock before provider lock
147 * DTrace before provider lock
148 * creation lock before DTrace
149 * never hold the provider lock and creation lock simultaneously
150 */
151
152static d_open_t fasttrap_open;
153static d_ioctl_t fasttrap_ioctl;
154
155static struct cdevsw fasttrap_cdevsw = {
156 .d_version = D_VERSION,
157 .d_open = fasttrap_open,
158 .d_ioctl = fasttrap_ioctl,
159 .d_name = "fasttrap",
160};
161static struct cdev *fasttrap_cdev;
162static dtrace_meta_provider_id_t fasttrap_meta_id;
163
164static struct proc *fasttrap_cleanup_proc;
165static struct mtx fasttrap_cleanup_mtx;
166static uint_t fasttrap_cleanup_work, fasttrap_cleanup_drain, fasttrap_cleanup_cv;
167
168/*
169 * Generation count on modifications to the global tracepoint lookup table.
170 */
171static volatile uint64_t fasttrap_mod_gen;
172
173/*
174 * When the fasttrap provider is loaded, fasttrap_max is set to either
175 * FASTTRAP_MAX_DEFAULT or the value for fasttrap-max-probes in the
176 * fasttrap.conf file. Each time a probe is created, fasttrap_total is
177 * incremented by the number of tracepoints that may be associated with that
178 * probe; fasttrap_total is capped at fasttrap_max.
179 */
180#define FASTTRAP_MAX_DEFAULT 250000
181static uint32_t fasttrap_max;
182static uint32_t fasttrap_total;
183
184/*
185 * Copyright (c) 2011, Joyent, Inc. All rights reserved.
186 */
187
188#define FASTTRAP_TPOINTS_DEFAULT_SIZE 0x4000
189#define FASTTRAP_PROVIDERS_DEFAULT_SIZE 0x100
190#define FASTTRAP_PROCS_DEFAULT_SIZE 0x100
191
192#define FASTTRAP_PID_NAME "pid"
193
194fasttrap_hash_t fasttrap_tpoints;
195static fasttrap_hash_t fasttrap_provs;
196static fasttrap_hash_t fasttrap_procs;
197
198static uint64_t fasttrap_pid_count; /* pid ref count */
199static kmutex_t fasttrap_count_mtx; /* lock on ref count */
200
201#define FASTTRAP_ENABLE_FAIL 1
202#define FASTTRAP_ENABLE_PARTIAL 2
203
204static int fasttrap_tracepoint_enable(proc_t *, fasttrap_probe_t *, uint_t);
205static void fasttrap_tracepoint_disable(proc_t *, fasttrap_probe_t *, uint_t);
206
207static fasttrap_provider_t *fasttrap_provider_lookup(pid_t, const char *,
208 const dtrace_pattr_t *);
209static void fasttrap_provider_retire(pid_t, const char *, int);
210static void fasttrap_provider_free(fasttrap_provider_t *);
211
212static fasttrap_proc_t *fasttrap_proc_lookup(pid_t);
213static void fasttrap_proc_release(fasttrap_proc_t *);
214
215#if !defined(sun)
216static void fasttrap_thread_dtor(void *, struct thread *);
217#endif
218
219#define FASTTRAP_PROVS_INDEX(pid, name) \
220 ((fasttrap_hash_str(name) + (pid)) & fasttrap_provs.fth_mask)
221
222#define FASTTRAP_PROCS_INDEX(pid) ((pid) & fasttrap_procs.fth_mask)
223
224#if !defined(sun)
225static kmutex_t fasttrap_cpuc_pid_lock[MAXCPU];
226static eventhandler_tag fasttrap_thread_dtor_tag;
227#endif
228
229static int
230fasttrap_highbit(ulong_t i)
231{
232 int h = 1;
233
234 if (i == 0)
235 return (0);
236#ifdef _LP64
237 if (i & 0xffffffff00000000ul) {
238 h += 32; i >>= 32;
239 }
240#endif
241 if (i & 0xffff0000) {
242 h += 16; i >>= 16;
243 }
244 if (i & 0xff00) {
245 h += 8; i >>= 8;
246 }
247 if (i & 0xf0) {
248 h += 4; i >>= 4;
249 }
250 if (i & 0xc) {
251 h += 2; i >>= 2;
252 }
253 if (i & 0x2) {
254 h += 1;
255 }
256 return (h);
257}
258
259static uint_t
260fasttrap_hash_str(const char *p)
261{
262 unsigned int g;
263 uint_t hval = 0;
264
265 while (*p) {
266 hval = (hval << 4) + *p++;
267 if ((g = (hval & 0xf0000000)) != 0)
268 hval ^= g >> 24;
269 hval &= ~g;
270 }
271 return (hval);
272}
273
274void
275fasttrap_sigtrap(proc_t *p, kthread_t *t, uintptr_t pc)
276{
277#if defined(sun)
278 sigqueue_t *sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP);
279
280 sqp->sq_info.si_signo = SIGTRAP;
281 sqp->sq_info.si_code = TRAP_DTRACE;
282 sqp->sq_info.si_addr = (caddr_t)pc;
283
284 mutex_enter(&p->p_lock);
285 sigaddqa(p, t, sqp);
286 mutex_exit(&p->p_lock);
287
288 if (t != NULL)
289 aston(t);
290#else
291 ksiginfo_t *ksi = kmem_zalloc(sizeof (ksiginfo_t), KM_SLEEP);
292
293 ksiginfo_init(ksi);
294 ksi->ksi_signo = SIGTRAP;
295 ksi->ksi_code = TRAP_DTRACE;
296 ksi->ksi_addr = (caddr_t)pc;
297 PROC_LOCK(p);
298 (void) tdksignal(t, SIGTRAP, ksi);
299 PROC_UNLOCK(p);
300#endif
301}
302
303#if !defined(sun)
304/*
305 * Obtain a chunk of scratch space in the address space of the target process.
306 */
307fasttrap_scrspace_t *
308fasttrap_scraddr(struct thread *td, fasttrap_proc_t *fprc)
309{
310 fasttrap_scrblock_t *scrblk;
311 fasttrap_scrspace_t *scrspc;
312 struct proc *p;
313 vm_offset_t addr;
314 int error, i;
315
316 scrspc = NULL;
317 if (td->t_dtrace_sscr != NULL) {
318 /* If the thread already has scratch space, we're done. */
319 scrspc = (fasttrap_scrspace_t *)td->t_dtrace_sscr;
320 return (scrspc);
321 }
322
323 p = td->td_proc;
324
325 mutex_enter(&fprc->ftpc_mtx);
326 if (LIST_EMPTY(&fprc->ftpc_fscr)) {
327 /*
328 * No scratch space is available, so we'll map a new scratch
329 * space block into the traced process' address space.
330 */
331 addr = 0;
332 error = vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr,
333 FASTTRAP_SCRBLOCK_SIZE, 0, VMFS_ANY_SPACE, VM_PROT_ALL,
334 VM_PROT_ALL, 0);
335 if (error != KERN_SUCCESS)
336 goto done;
337
338 scrblk = malloc(sizeof(*scrblk), M_SOLARIS, M_WAITOK);
339 scrblk->ftsb_addr = addr;
340 LIST_INSERT_HEAD(&fprc->ftpc_scrblks, scrblk, ftsb_next);
341
342 /*
343 * Carve the block up into chunks and put them on the free list.
344 */
345 for (i = 0;
346 i < FASTTRAP_SCRBLOCK_SIZE / FASTTRAP_SCRSPACE_SIZE; i++) {
347 scrspc = malloc(sizeof(*scrspc), M_SOLARIS, M_WAITOK);
348 scrspc->ftss_addr = addr +
349 i * FASTTRAP_SCRSPACE_SIZE;
350 LIST_INSERT_HEAD(&fprc->ftpc_fscr, scrspc,
351 ftss_next);
352 }
353 }
354
355 /*
356 * Take the first scratch chunk off the free list, put it on the
357 * allocated list, and return its address.
358 */
359 scrspc = LIST_FIRST(&fprc->ftpc_fscr);
360 LIST_REMOVE(scrspc, ftss_next);
361 LIST_INSERT_HEAD(&fprc->ftpc_ascr, scrspc, ftss_next);
362
363 /*
364 * This scratch space is reserved for use by td until the thread exits.
365 */
366 td->t_dtrace_sscr = scrspc;
367
368done:
369 mutex_exit(&fprc->ftpc_mtx);
370
371 return (scrspc);
372}
373
374/*
375 * Return any allocated per-thread scratch space chunks back to the process'
376 * free list.
377 */
378static void
379fasttrap_thread_dtor(void *arg __unused, struct thread *td)
380{
381 fasttrap_bucket_t *bucket;
382 fasttrap_proc_t *fprc;
383 fasttrap_scrspace_t *scrspc;
384 pid_t pid;
385
386 if (td->t_dtrace_sscr == NULL)
387 return;
388
389 pid = td->td_proc->p_pid;
390 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
391 fprc = NULL;
392
393 /* Look up the fasttrap process handle for this process. */
394 mutex_enter(&bucket->ftb_mtx);
395 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
396 if (fprc->ftpc_pid == pid) {
397 mutex_enter(&fprc->ftpc_mtx);
398 mutex_exit(&bucket->ftb_mtx);
399 break;
400 }
401 }
402 if (fprc == NULL) {
403 mutex_exit(&bucket->ftb_mtx);
404 return;
405 }
406
407 scrspc = (fasttrap_scrspace_t *)td->t_dtrace_sscr;
408 LIST_REMOVE(scrspc, ftss_next);
409 LIST_INSERT_HEAD(&fprc->ftpc_fscr, scrspc, ftss_next);
410
411 mutex_exit(&fprc->ftpc_mtx);
412}
413#endif
414
415/*
416 * This function ensures that no threads are actively using the memory
417 * associated with probes that were formerly live.
418 */
419static void
420fasttrap_mod_barrier(uint64_t gen)
421{
422 int i;
423
424 if (gen < fasttrap_mod_gen)
425 return;
426
427 fasttrap_mod_gen++;
428
429 CPU_FOREACH(i) {
430 mutex_enter(&fasttrap_cpuc_pid_lock[i]);
431 mutex_exit(&fasttrap_cpuc_pid_lock[i]);
432 }
433}
434
435/*
436 * This function performs asynchronous cleanup of fasttrap providers. The
437 * Solaris implementation of this mechanism use a timeout that's activated in
438 * fasttrap_pid_cleanup(), but this doesn't work in FreeBSD: one may sleep while
439 * holding the DTrace mutexes, but it is unsafe to sleep in a callout handler.
440 * Thus we use a dedicated process to perform the cleanup when requested.
441 */
442/*ARGSUSED*/
443static void
444fasttrap_pid_cleanup_cb(void *data)
445{
446 fasttrap_provider_t **fpp, *fp;
447 fasttrap_bucket_t *bucket;
448 dtrace_provider_id_t provid;
449 int i, later = 0, rval;
450
451 mtx_lock(&fasttrap_cleanup_mtx);
452 while (!fasttrap_cleanup_drain || later > 0) {
453 fasttrap_cleanup_work = 0;
454 mtx_unlock(&fasttrap_cleanup_mtx);
455
456 later = 0;
457
458 /*
459 * Iterate over all the providers trying to remove the marked
460 * ones. If a provider is marked but not retired, we just
461 * have to take a crack at removing it -- it's no big deal if
462 * we can't.
463 */
464 for (i = 0; i < fasttrap_provs.fth_nent; i++) {
465 bucket = &fasttrap_provs.fth_table[i];
466 mutex_enter(&bucket->ftb_mtx);
467 fpp = (fasttrap_provider_t **)&bucket->ftb_data;
468
469 while ((fp = *fpp) != NULL) {
470 if (!fp->ftp_marked) {
471 fpp = &fp->ftp_next;
472 continue;
473 }
474
475 mutex_enter(&fp->ftp_mtx);
476
477 /*
478 * If this provider has consumers actively
479 * creating probes (ftp_ccount) or is a USDT
480 * provider (ftp_mcount), we can't unregister
481 * or even condense.
482 */
483 if (fp->ftp_ccount != 0 ||
484 fp->ftp_mcount != 0) {
485 mutex_exit(&fp->ftp_mtx);
486 fp->ftp_marked = 0;
487 continue;
488 }
489
490 if (!fp->ftp_retired || fp->ftp_rcount != 0)
491 fp->ftp_marked = 0;
492
493 mutex_exit(&fp->ftp_mtx);
494
495 /*
496 * If we successfully unregister this
497 * provider we can remove it from the hash
498 * chain and free the memory. If our attempt
499 * to unregister fails and this is a retired
500 * provider, increment our flag to try again
501 * pretty soon. If we've consumed more than
502 * half of our total permitted number of
503 * probes call dtrace_condense() to try to
504 * clean out the unenabled probes.
505 */
506 provid = fp->ftp_provid;
507 if ((rval = dtrace_unregister(provid)) != 0) {
508 if (fasttrap_total > fasttrap_max / 2)
509 (void) dtrace_condense(provid);
510
511 if (rval == EAGAIN)
512 fp->ftp_marked = 1;
513
514 later += fp->ftp_marked;
515 fpp = &fp->ftp_next;
516 } else {
517 *fpp = fp->ftp_next;
518 fasttrap_provider_free(fp);
519 }
520 }
521 mutex_exit(&bucket->ftb_mtx);
522 }
523 mtx_lock(&fasttrap_cleanup_mtx);
524
525 /*
526 * If we were unable to retire a provider, try again after a
527 * second. This situation can occur in certain circumstances
528 * where providers cannot be unregistered even though they have
529 * no probes enabled because of an execution of dtrace -l or
530 * something similar.
531 */
532 if (later > 0 || fasttrap_cleanup_work ||
533 fasttrap_cleanup_drain) {
534 mtx_unlock(&fasttrap_cleanup_mtx);
535 pause("ftclean", hz);
536 mtx_lock(&fasttrap_cleanup_mtx);
537 } else
538 mtx_sleep(&fasttrap_cleanup_cv, &fasttrap_cleanup_mtx,
539 0, "ftcl", 0);
540 }
541
542 /*
543 * Wake up the thread in fasttrap_unload() now that we're done.
544 */
545 wakeup(&fasttrap_cleanup_drain);
546 mtx_unlock(&fasttrap_cleanup_mtx);
547
548 kthread_exit();
549}
550
551/*
552 * Activates the asynchronous cleanup mechanism.
553 */
554static void
555fasttrap_pid_cleanup(void)
556{
557
558 mtx_lock(&fasttrap_cleanup_mtx);
559 if (!fasttrap_cleanup_work) {
560 fasttrap_cleanup_work = 1;
561 wakeup(&fasttrap_cleanup_cv);
562 }
563 mtx_unlock(&fasttrap_cleanup_mtx);
564}
565
566/*
567 * This is called from cfork() via dtrace_fasttrap_fork(). The child
568 * process's address space is (roughly) a copy of the parent process's so
569 * we have to remove all the instrumentation we had previously enabled in the
570 * parent.
571 */
572static void
573fasttrap_fork(proc_t *p, proc_t *cp)
574{
575#if !defined(sun)
576 fasttrap_scrblock_t *scrblk;
577 fasttrap_proc_t *fprc = NULL;
578#endif
579 pid_t ppid = p->p_pid;
580 int i;
581
582#if defined(sun)
583 ASSERT(curproc == p);
584 ASSERT(p->p_proc_flag & P_PR_LOCK);
585#else
586 PROC_LOCK_ASSERT(p, MA_OWNED);
587#endif
588#if defined(sun)
589 ASSERT(p->p_dtrace_count > 0);
590#else
591 if (p->p_dtrace_helpers) {
592 /*
593 * dtrace_helpers_duplicate() allocates memory.
594 */
595 _PHOLD(cp);
596 PROC_UNLOCK(p);
597 PROC_UNLOCK(cp);
598 dtrace_helpers_duplicate(p, cp);
599 PROC_LOCK(cp);
600 PROC_LOCK(p);
601 _PRELE(cp);
602 }
603 /*
604 * This check is purposely here instead of in kern_fork.c because,
605 * for legal resons, we cannot include the dtrace_cddl.h header
606 * inside kern_fork.c and insert if-clause there.
607 */
608 if (p->p_dtrace_count == 0)
609 return;
610#endif
611 ASSERT(cp->p_dtrace_count == 0);
612
613 /*
614 * This would be simpler and faster if we maintained per-process
615 * hash tables of enabled tracepoints. It could, however, potentially
616 * slow down execution of a tracepoint since we'd need to go
617 * through two levels of indirection. In the future, we should
618 * consider either maintaining per-process ancillary lists of
619 * enabled tracepoints or hanging a pointer to a per-process hash
620 * table of enabled tracepoints off the proc structure.
621 */
622
623 /*
624 * We don't have to worry about the child process disappearing
625 * because we're in fork().
626 */
627#if defined(sun)
628 mtx_lock_spin(&cp->p_slock);
629 sprlock_proc(cp);
630 mtx_unlock_spin(&cp->p_slock);
631#else
632 /*
633 * fasttrap_tracepoint_remove() expects the child process to be
634 * unlocked and the VM then expects curproc to be unlocked.
635 */
636 _PHOLD(cp);
637 PROC_UNLOCK(cp);
638 PROC_UNLOCK(p);
639#endif
640
641 /*
642 * Iterate over every tracepoint looking for ones that belong to the
643 * parent process, and remove each from the child process.
644 */
645 for (i = 0; i < fasttrap_tpoints.fth_nent; i++) {
646 fasttrap_tracepoint_t *tp;
647 fasttrap_bucket_t *bucket = &fasttrap_tpoints.fth_table[i];
648
649 mutex_enter(&bucket->ftb_mtx);
650 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
651 if (tp->ftt_pid == ppid &&
652 tp->ftt_proc->ftpc_acount != 0) {
653 int ret = fasttrap_tracepoint_remove(cp, tp);
654 ASSERT(ret == 0);
655
656 /*
657 * The count of active providers can only be
658 * decremented (i.e. to zero) during exec,
659 * exit, and removal of a meta provider so it
660 * should be impossible to drop the count
661 * mid-fork.
662 */
663 ASSERT(tp->ftt_proc->ftpc_acount != 0);
664#if !defined(sun)
665 fprc = tp->ftt_proc;
666#endif
667 }
668 }
669 mutex_exit(&bucket->ftb_mtx);
670
671#if !defined(sun)
672 /*
673 * Unmap any scratch space inherited from the parent's address
674 * space.
675 */
676 if (fprc != NULL) {
677 mutex_enter(&fprc->ftpc_mtx);
678 LIST_FOREACH(scrblk, &fprc->ftpc_scrblks, ftsb_next) {
679 vm_map_remove(&cp->p_vmspace->vm_map,
680 scrblk->ftsb_addr,
681 scrblk->ftsb_addr + FASTTRAP_SCRBLOCK_SIZE);
682 }
683 mutex_exit(&fprc->ftpc_mtx);
684 }
685#endif
686 }
687
688#if defined(sun)
689 mutex_enter(&cp->p_lock);
690 sprunlock(cp);
691#else
692 PROC_LOCK(p);
693 PROC_LOCK(cp);
694 _PRELE(cp);
695#endif
696}
697
698/*
699 * This is called from proc_exit() or from exec_common() if p_dtrace_probes
700 * is set on the proc structure to indicate that there is a pid provider
701 * associated with this process.
702 */
703static void
704fasttrap_exec_exit(proc_t *p)
705{
706#if !defined(sun)
707 struct thread *td;
708#endif
709
710#if defined(sun)
711 ASSERT(p == curproc);
712#else
713 PROC_LOCK_ASSERT(p, MA_OWNED);
714 _PHOLD(p);
715 /*
716 * Since struct threads may be recycled, we cannot rely on t_dtrace_sscr
717 * fields to be zeroed by kdtrace_thread_ctor. Thus we must zero it
718 * ourselves when a process exits.
719 */
720 FOREACH_THREAD_IN_PROC(p, td)
721 td->t_dtrace_sscr = NULL;
722 PROC_UNLOCK(p);
723#endif
724
725 /*
726 * We clean up the pid provider for this process here; user-land
727 * static probes are handled by the meta-provider remove entry point.
728 */
729 fasttrap_provider_retire(p->p_pid, FASTTRAP_PID_NAME, 0);
730#if !defined(sun)
731 if (p->p_dtrace_helpers)
732 dtrace_helpers_destroy(p);
733 PROC_LOCK(p);
734 _PRELE(p);
735#endif
736}
737
738
739/*ARGSUSED*/
740static void
741fasttrap_pid_provide(void *arg, dtrace_probedesc_t *desc)
742{
743 /*
744 * There are no "default" pid probes.
745 */
746}
747
748static int
749fasttrap_tracepoint_enable(proc_t *p, fasttrap_probe_t *probe, uint_t index)
750{
751 fasttrap_tracepoint_t *tp, *new_tp = NULL;
752 fasttrap_bucket_t *bucket;
753 fasttrap_id_t *id;
754 pid_t pid;
755 uintptr_t pc;
756
757 ASSERT(index < probe->ftp_ntps);
758
759 pid = probe->ftp_pid;
760 pc = probe->ftp_tps[index].fit_tp->ftt_pc;
761 id = &probe->ftp_tps[index].fit_id;
762
763 ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid);
764
765#if defined(sun)
766 ASSERT(!(p->p_flag & SVFORK));
767#endif
768
769 /*
770 * Before we make any modifications, make sure we've imposed a barrier
771 * on the generation in which this probe was last modified.
772 */
773 fasttrap_mod_barrier(probe->ftp_gen);
774
775 bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
776
777 /*
778 * If the tracepoint has already been enabled, just add our id to the
779 * list of interested probes. This may be our second time through
780 * this path in which case we'll have constructed the tracepoint we'd
781 * like to install. If we can't find a match, and have an allocated
782 * tracepoint ready to go, enable that one now.
783 *
784 * A tracepoint whose process is defunct is also considered defunct.
785 */
786again:
787 mutex_enter(&bucket->ftb_mtx);
788 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
789 /*
790 * Note that it's safe to access the active count on the
791 * associated proc structure because we know that at least one
792 * provider (this one) will still be around throughout this
793 * operation.
794 */
795 if (tp->ftt_pid != pid || tp->ftt_pc != pc ||
796 tp->ftt_proc->ftpc_acount == 0)
797 continue;
798
799 /*
800 * Now that we've found a matching tracepoint, it would be
801 * a decent idea to confirm that the tracepoint is still
802 * enabled and the trap instruction hasn't been overwritten.
803 * Since this is a little hairy, we'll punt for now.
804 */
805
806 /*
807 * This can't be the first interested probe. We don't have
808 * to worry about another thread being in the midst of
809 * deleting this tracepoint (which would be the only valid
810 * reason for a tracepoint to have no interested probes)
811 * since we're holding P_PR_LOCK for this process.
812 */
813 ASSERT(tp->ftt_ids != NULL || tp->ftt_retids != NULL);
814
815 switch (id->fti_ptype) {
816 case DTFTP_ENTRY:
817 case DTFTP_OFFSETS:
818 case DTFTP_IS_ENABLED:
819 id->fti_next = tp->ftt_ids;
820 membar_producer();
821 tp->ftt_ids = id;
822 membar_producer();
823 break;
824
825 case DTFTP_RETURN:
826 case DTFTP_POST_OFFSETS:
827 id->fti_next = tp->ftt_retids;
828 membar_producer();
829 tp->ftt_retids = id;
830 membar_producer();
831 break;
832
833 default:
834 ASSERT(0);
835 }
836
837 mutex_exit(&bucket->ftb_mtx);
838
839 if (new_tp != NULL) {
840 new_tp->ftt_ids = NULL;
841 new_tp->ftt_retids = NULL;
842 }
843
844 return (0);
845 }
846
847 /*
848 * If we have a good tracepoint ready to go, install it now while
849 * we have the lock held and no one can screw with us.
850 */
851 if (new_tp != NULL) {
852 int rc = 0;
853
854 new_tp->ftt_next = bucket->ftb_data;
855 membar_producer();
856 bucket->ftb_data = new_tp;
857 membar_producer();
858 mutex_exit(&bucket->ftb_mtx);
859
860 /*
861 * Activate the tracepoint in the ISA-specific manner.
862 * If this fails, we need to report the failure, but
863 * indicate that this tracepoint must still be disabled
864 * by calling fasttrap_tracepoint_disable().
865 */
866 if (fasttrap_tracepoint_install(p, new_tp) != 0)
867 rc = FASTTRAP_ENABLE_PARTIAL;
868
869 /*
870 * Increment the count of the number of tracepoints active in
871 * the victim process.
872 */
873#if defined(sun)
874 ASSERT(p->p_proc_flag & P_PR_LOCK);
875#endif
876 p->p_dtrace_count++;
877
878 return (rc);
879 }
880
881 mutex_exit(&bucket->ftb_mtx);
882
883 /*
884 * Initialize the tracepoint that's been preallocated with the probe.
885 */
886 new_tp = probe->ftp_tps[index].fit_tp;
887
888 ASSERT(new_tp->ftt_pid == pid);
889 ASSERT(new_tp->ftt_pc == pc);
890 ASSERT(new_tp->ftt_proc == probe->ftp_prov->ftp_proc);
891 ASSERT(new_tp->ftt_ids == NULL);
892 ASSERT(new_tp->ftt_retids == NULL);
893
894 switch (id->fti_ptype) {
895 case DTFTP_ENTRY:
896 case DTFTP_OFFSETS:
897 case DTFTP_IS_ENABLED:
898 id->fti_next = NULL;
899 new_tp->ftt_ids = id;
900 break;
901
902 case DTFTP_RETURN:
903 case DTFTP_POST_OFFSETS:
904 id->fti_next = NULL;
905 new_tp->ftt_retids = id;
906 break;
907
908 default:
909 ASSERT(0);
910 }
911
912 /*
913 * If the ISA-dependent initialization goes to plan, go back to the
914 * beginning and try to install this freshly made tracepoint.
915 */
916 if (fasttrap_tracepoint_init(p, new_tp, pc, id->fti_ptype) == 0)
917 goto again;
918
919 new_tp->ftt_ids = NULL;
920 new_tp->ftt_retids = NULL;
921
922 return (FASTTRAP_ENABLE_FAIL);
923}
924
925static void
926fasttrap_tracepoint_disable(proc_t *p, fasttrap_probe_t *probe, uint_t index)
927{
928 fasttrap_bucket_t *bucket;
929 fasttrap_provider_t *provider = probe->ftp_prov;
930 fasttrap_tracepoint_t **pp, *tp;
931 fasttrap_id_t *id, **idp = NULL;
932 pid_t pid;
933 uintptr_t pc;
934
935 ASSERT(index < probe->ftp_ntps);
936
937 pid = probe->ftp_pid;
938 pc = probe->ftp_tps[index].fit_tp->ftt_pc;
939 id = &probe->ftp_tps[index].fit_id;
940
941 ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid);
942
943 /*
944 * Find the tracepoint and make sure that our id is one of the
945 * ones registered with it.
946 */
947 bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
948 mutex_enter(&bucket->ftb_mtx);
949 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
950 if (tp->ftt_pid == pid && tp->ftt_pc == pc &&
951 tp->ftt_proc == provider->ftp_proc)
952 break;
953 }
954
955 /*
956 * If we somehow lost this tracepoint, we're in a world of hurt.
957 */
958 ASSERT(tp != NULL);
959
960 switch (id->fti_ptype) {
961 case DTFTP_ENTRY:
962 case DTFTP_OFFSETS:
963 case DTFTP_IS_ENABLED:
964 ASSERT(tp->ftt_ids != NULL);
965 idp = &tp->ftt_ids;
966 break;
967
968 case DTFTP_RETURN:
969 case DTFTP_POST_OFFSETS:
970 ASSERT(tp->ftt_retids != NULL);
971 idp = &tp->ftt_retids;
972 break;
973
974 default:
975 ASSERT(0);
976 }
977
978 while ((*idp)->fti_probe != probe) {
979 idp = &(*idp)->fti_next;
980 ASSERT(*idp != NULL);
981 }
982
983 id = *idp;
984 *idp = id->fti_next;
985 membar_producer();
986
987 ASSERT(id->fti_probe == probe);
988
989 /*
990 * If there are other registered enablings of this tracepoint, we're
991 * all done, but if this was the last probe assocated with this
992 * this tracepoint, we need to remove and free it.
993 */
994 if (tp->ftt_ids != NULL || tp->ftt_retids != NULL) {
995
996 /*
997 * If the current probe's tracepoint is in use, swap it
998 * for an unused tracepoint.
999 */
1000 if (tp == probe->ftp_tps[index].fit_tp) {
1001 fasttrap_probe_t *tmp_probe;
1002 fasttrap_tracepoint_t **tmp_tp;
1003 uint_t tmp_index;
1004
1005 if (tp->ftt_ids != NULL) {
1006 tmp_probe = tp->ftt_ids->fti_probe;
1007 /* LINTED - alignment */
1008 tmp_index = FASTTRAP_ID_INDEX(tp->ftt_ids);
1009 tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp;
1010 } else {
1011 tmp_probe = tp->ftt_retids->fti_probe;
1012 /* LINTED - alignment */
1013 tmp_index = FASTTRAP_ID_INDEX(tp->ftt_retids);
1014 tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp;
1015 }
1016
1017 ASSERT(*tmp_tp != NULL);
1018 ASSERT(*tmp_tp != probe->ftp_tps[index].fit_tp);
1019 ASSERT((*tmp_tp)->ftt_ids == NULL);
1020 ASSERT((*tmp_tp)->ftt_retids == NULL);
1021
1022 probe->ftp_tps[index].fit_tp = *tmp_tp;
1023 *tmp_tp = tp;
1024 }
1025
1026 mutex_exit(&bucket->ftb_mtx);
1027
1028 /*
1029 * Tag the modified probe with the generation in which it was
1030 * changed.
1031 */
1032 probe->ftp_gen = fasttrap_mod_gen;
1033 return;
1034 }
1035
1036 mutex_exit(&bucket->ftb_mtx);
1037
1038 /*
1039 * We can't safely remove the tracepoint from the set of active
1040 * tracepoints until we've actually removed the fasttrap instruction
1041 * from the process's text. We can, however, operate on this
1042 * tracepoint secure in the knowledge that no other thread is going to
1043 * be looking at it since we hold P_PR_LOCK on the process if it's
1044 * live or we hold the provider lock on the process if it's dead and
1045 * gone.
1046 */
1047
1048 /*
1049 * We only need to remove the actual instruction if we're looking
1050 * at an existing process
1051 */
1052 if (p != NULL) {
1053 /*
1054 * If we fail to restore the instruction we need to kill
1055 * this process since it's in a completely unrecoverable
1056 * state.
1057 */
1058 if (fasttrap_tracepoint_remove(p, tp) != 0)
1059 fasttrap_sigtrap(p, NULL, pc);
1060
1061 /*
1062 * Decrement the count of the number of tracepoints active
1063 * in the victim process.
1064 */
1065#if defined(sun)
1066 ASSERT(p->p_proc_flag & P_PR_LOCK);
1067#endif
1068 p->p_dtrace_count--;
1069 }
1070
1071 /*
1072 * Remove the probe from the hash table of active tracepoints.
1073 */
1074 mutex_enter(&bucket->ftb_mtx);
1075 pp = (fasttrap_tracepoint_t **)&bucket->ftb_data;
1076 ASSERT(*pp != NULL);
1077 while (*pp != tp) {
1078 pp = &(*pp)->ftt_next;
1079 ASSERT(*pp != NULL);
1080 }
1081
1082 *pp = tp->ftt_next;
1083 membar_producer();
1084
1085 mutex_exit(&bucket->ftb_mtx);
1086
1087 /*
1088 * Tag the modified probe with the generation in which it was changed.
1089 */
1090 probe->ftp_gen = fasttrap_mod_gen;
1091}
1092
1093static void
1094fasttrap_enable_callbacks(void)
1095{
1096 /*
1097 * We don't have to play the rw lock game here because we're
1098 * providing something rather than taking something away --
1099 * we can be sure that no threads have tried to follow this
1100 * function pointer yet.
1101 */
1102 mutex_enter(&fasttrap_count_mtx);
1103 if (fasttrap_pid_count == 0) {
1104 ASSERT(dtrace_pid_probe_ptr == NULL);
1105 ASSERT(dtrace_return_probe_ptr == NULL);
1106 dtrace_pid_probe_ptr = &fasttrap_pid_probe;
1107 dtrace_return_probe_ptr = &fasttrap_return_probe;
1108 }
1109 ASSERT(dtrace_pid_probe_ptr == &fasttrap_pid_probe);
1110 ASSERT(dtrace_return_probe_ptr == &fasttrap_return_probe);
1111 fasttrap_pid_count++;
1112 mutex_exit(&fasttrap_count_mtx);
1113}
1114
1115static void
1116fasttrap_disable_callbacks(void)
1117{
1118#if defined(sun)
1119 ASSERT(MUTEX_HELD(&cpu_lock));
1120#endif
1121
1122
1123 mutex_enter(&fasttrap_count_mtx);
1124 ASSERT(fasttrap_pid_count > 0);
1125 fasttrap_pid_count--;
1126 if (fasttrap_pid_count == 0) {
1127#if defined(sun)
1128 cpu_t *cur, *cpu = CPU;
1129
1130 for (cur = cpu->cpu_next_onln; cur != cpu;
1131 cur = cur->cpu_next_onln) {
1132 rw_enter(&cur->cpu_ft_lock, RW_WRITER);
1133 }
1134#endif
1135 dtrace_pid_probe_ptr = NULL;
1136 dtrace_return_probe_ptr = NULL;
1137#if defined(sun)
1138 for (cur = cpu->cpu_next_onln; cur != cpu;
1139 cur = cur->cpu_next_onln) {
1140 rw_exit(&cur->cpu_ft_lock);
1141 }
1142#endif
1143 }
1144 mutex_exit(&fasttrap_count_mtx);
1145}
1146
1147/*ARGSUSED*/
1148static void
1149fasttrap_pid_enable(void *arg, dtrace_id_t id, void *parg)
1150{
1151 fasttrap_probe_t *probe = parg;
1152 proc_t *p = NULL;
1153 int i, rc;
1154
1155 ASSERT(probe != NULL);
1156 ASSERT(!probe->ftp_enabled);
1157 ASSERT(id == probe->ftp_id);
1158#if defined(sun)
1159 ASSERT(MUTEX_HELD(&cpu_lock));
1160#endif
1161
1162 /*
1163 * Increment the count of enabled probes on this probe's provider;
1164 * the provider can't go away while the probe still exists. We
1165 * must increment this even if we aren't able to properly enable
1166 * this probe.
1167 */
1168 mutex_enter(&probe->ftp_prov->ftp_mtx);
1169 probe->ftp_prov->ftp_rcount++;
1170 mutex_exit(&probe->ftp_prov->ftp_mtx);
1171
1172 /*
1173 * If this probe's provider is retired (meaning it was valid in a
1174 * previously exec'ed incarnation of this address space), bail out. The
1175 * provider can't go away while we're in this code path.
1176 */
1177 if (probe->ftp_prov->ftp_retired)
1178 return;
1179
1180 /*
1181 * If we can't find the process, it may be that we're in the context of
1182 * a fork in which the traced process is being born and we're copying
1183 * USDT probes. Otherwise, the process is gone so bail.
1184 */
1185#if defined(sun)
1186 if ((p = sprlock(probe->ftp_pid)) == NULL) {
1187 if ((curproc->p_flag & SFORKING) == 0)
1188 return;
1189
1190 mutex_enter(&pidlock);
1191 p = prfind(probe->ftp_pid);
1192
1193 /*
1194 * Confirm that curproc is indeed forking the process in which
1195 * we're trying to enable probes.
1196 */
1197 ASSERT(p != NULL);
1198 ASSERT(p->p_parent == curproc);
1199 ASSERT(p->p_stat == SIDL);
1200
1201 mutex_enter(&p->p_lock);
1202 mutex_exit(&pidlock);
1203
1204 sprlock_proc(p);
1205 }
1206
1207 ASSERT(!(p->p_flag & SVFORK));
1208 mutex_exit(&p->p_lock);
1209#else
1210 if ((p = pfind(probe->ftp_pid)) == NULL)
1211 return;
1212#endif
1213
1214 /*
1215 * We have to enable the trap entry point before any user threads have
1216 * the chance to execute the trap instruction we're about to place
1217 * in their process's text.
1218 */
1219#ifdef __FreeBSD__
1220 /*
1221 * pfind() returns a locked process.
1222 */
1223 _PHOLD(p);
1224 PROC_UNLOCK(p);
1225#endif
1226 fasttrap_enable_callbacks();
1227
1228 /*
1229 * Enable all the tracepoints and add this probe's id to each
1230 * tracepoint's list of active probes.
1231 */
1232 for (i = 0; i < probe->ftp_ntps; i++) {
1233 if ((rc = fasttrap_tracepoint_enable(p, probe, i)) != 0) {
1234 /*
1235 * If enabling the tracepoint failed completely,
1236 * we don't have to disable it; if the failure
1237 * was only partial we must disable it.
1238 */
1239 if (rc == FASTTRAP_ENABLE_FAIL)
1240 i--;
1241 else
1242 ASSERT(rc == FASTTRAP_ENABLE_PARTIAL);
1243
1244 /*
1245 * Back up and pull out all the tracepoints we've
1246 * created so far for this probe.
1247 */
1248 while (i >= 0) {
1249 fasttrap_tracepoint_disable(p, probe, i);
1250 i--;
1251 }
1252
1253#if defined(sun)
1254 mutex_enter(&p->p_lock);
1255 sprunlock(p);
1256#else
1257 PRELE(p);
1258#endif
1259
1260 /*
1261 * Since we're not actually enabling this probe,
1262 * drop our reference on the trap table entry.
1263 */
1264 fasttrap_disable_callbacks();
1265 return;
1266 }
1267 }
1268#if defined(sun)
1269 mutex_enter(&p->p_lock);
1270 sprunlock(p);
1271#else
1272 PRELE(p);
1273#endif
1274
1275 probe->ftp_enabled = 1;
1276}
1277
1278/*ARGSUSED*/
1279static void
1280fasttrap_pid_disable(void *arg, dtrace_id_t id, void *parg)
1281{
1282 fasttrap_probe_t *probe = parg;
1283 fasttrap_provider_t *provider = probe->ftp_prov;
1284 proc_t *p;
1285 int i, whack = 0;
1286
1287 ASSERT(id == probe->ftp_id);
1288
1289 mutex_enter(&provider->ftp_mtx);
1290
1291 /*
1292 * We won't be able to acquire a /proc-esque lock on the process
1293 * iff the process is dead and gone. In this case, we rely on the
1294 * provider lock as a point of mutual exclusion to prevent other
1295 * DTrace consumers from disabling this probe.
1296 */
1297 if ((p = pfind(probe->ftp_pid)) != NULL) {
1298#ifdef __FreeBSD__
1299 _PHOLD(p);
1300 PROC_UNLOCK(p);
1301#endif
1302 }
1303
1304 /*
1305 * Disable all the associated tracepoints (for fully enabled probes).
1306 */
1307 if (probe->ftp_enabled) {
1308 for (i = 0; i < probe->ftp_ntps; i++) {
1309 fasttrap_tracepoint_disable(p, probe, i);
1310 }
1311 }
1312
1313 ASSERT(provider->ftp_rcount > 0);
1314 provider->ftp_rcount--;
1315
1316 if (p != NULL) {
1317 /*
1318 * Even though we may not be able to remove it entirely, we
1319 * mark this retired provider to get a chance to remove some
1320 * of the associated probes.
1321 */
1322 if (provider->ftp_retired && !provider->ftp_marked)
1323 whack = provider->ftp_marked = 1;
1324 mutex_exit(&provider->ftp_mtx);
1325 } else {
1326 /*
1327 * If the process is dead, we're just waiting for the
1328 * last probe to be disabled to be able to free it.
1329 */
1330 if (provider->ftp_rcount == 0 && !provider->ftp_marked)
1331 whack = provider->ftp_marked = 1;
1332 mutex_exit(&provider->ftp_mtx);
1333 }
1334
1335 if (whack)
1336 fasttrap_pid_cleanup();
1337
1338#ifdef __FreeBSD__
1339 if (p != NULL)
1340 PRELE(p);
1341#endif
1342 if (!probe->ftp_enabled)
1343 return;
1344
1345 probe->ftp_enabled = 0;
1346
1347#if defined(sun)
1348 ASSERT(MUTEX_HELD(&cpu_lock));
1349#endif
1350 fasttrap_disable_callbacks();
1351}
1352
1353/*ARGSUSED*/
1354static void
1355fasttrap_pid_getargdesc(void *arg, dtrace_id_t id, void *parg,
1356 dtrace_argdesc_t *desc)
1357{
1358 fasttrap_probe_t *probe = parg;
1359 char *str;
1360 int i, ndx;
1361
1362 desc->dtargd_native[0] = '\0';
1363 desc->dtargd_xlate[0] = '\0';
1364
1365 if (probe->ftp_prov->ftp_retired != 0 ||
1366 desc->dtargd_ndx >= probe->ftp_nargs) {
1367 desc->dtargd_ndx = DTRACE_ARGNONE;
1368 return;
1369 }
1370
1371 ndx = (probe->ftp_argmap != NULL) ?
1372 probe->ftp_argmap[desc->dtargd_ndx] : desc->dtargd_ndx;
1373
1374 str = probe->ftp_ntypes;
1375 for (i = 0; i < ndx; i++) {
1376 str += strlen(str) + 1;
1377 }
1378
1379 ASSERT(strlen(str + 1) < sizeof (desc->dtargd_native));
1380 (void) strcpy(desc->dtargd_native, str);
1381
1382 if (probe->ftp_xtypes == NULL)
1383 return;
1384
1385 str = probe->ftp_xtypes;
1386 for (i = 0; i < desc->dtargd_ndx; i++) {
1387 str += strlen(str) + 1;
1388 }
1389
1390 ASSERT(strlen(str + 1) < sizeof (desc->dtargd_xlate));
1391 (void) strcpy(desc->dtargd_xlate, str);
1392}
1393
1394/*ARGSUSED*/
1395static void
1396fasttrap_pid_destroy(void *arg, dtrace_id_t id, void *parg)
1397{
1398 fasttrap_probe_t *probe = parg;
1399 int i;
1400 size_t size;
1401
1402 ASSERT(probe != NULL);
1403 ASSERT(!probe->ftp_enabled);
1404 ASSERT(fasttrap_total >= probe->ftp_ntps);
1405
1406 atomic_add_32(&fasttrap_total, -probe->ftp_ntps);
1407 size = offsetof(fasttrap_probe_t, ftp_tps[probe->ftp_ntps]);
1408
1409 if (probe->ftp_gen + 1 >= fasttrap_mod_gen)
1410 fasttrap_mod_barrier(probe->ftp_gen);
1411
1412 for (i = 0; i < probe->ftp_ntps; i++) {
1413 kmem_free(probe->ftp_tps[i].fit_tp,
1414 sizeof (fasttrap_tracepoint_t));
1415 }
1416
1417 kmem_free(probe, size);
1418}
1419
1420
1421static const dtrace_pattr_t pid_attr = {
1422{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
1423{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
1424{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
1425{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
1426{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
1427};
1428
1429static dtrace_pops_t pid_pops = {
1430 fasttrap_pid_provide,
1431 NULL,
1432 fasttrap_pid_enable,
1433 fasttrap_pid_disable,
1434 NULL,
1435 NULL,
1436 fasttrap_pid_getargdesc,
1437 fasttrap_pid_getarg,
1438 NULL,
1439 fasttrap_pid_destroy
1440};
1441
1442static dtrace_pops_t usdt_pops = {
1443 fasttrap_pid_provide,
1444 NULL,
1445 fasttrap_pid_enable,
1446 fasttrap_pid_disable,
1447 NULL,
1448 NULL,
1449 fasttrap_pid_getargdesc,
1450 fasttrap_usdt_getarg,
1451 NULL,
1452 fasttrap_pid_destroy
1453};
1454
1455static fasttrap_proc_t *
1456fasttrap_proc_lookup(pid_t pid)
1457{
1458 fasttrap_bucket_t *bucket;
1459 fasttrap_proc_t *fprc, *new_fprc;
1460
1461
1462 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
1463 mutex_enter(&bucket->ftb_mtx);
1464
1465 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
1466 if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) {
1467 mutex_enter(&fprc->ftpc_mtx);
1468 mutex_exit(&bucket->ftb_mtx);
1469 fprc->ftpc_rcount++;
1470 atomic_inc_64(&fprc->ftpc_acount);
1471 ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount);
1472 mutex_exit(&fprc->ftpc_mtx);
1473
1474 return (fprc);
1475 }
1476 }
1477
1478 /*
1479 * Drop the bucket lock so we don't try to perform a sleeping
1480 * allocation under it.
1481 */
1482 mutex_exit(&bucket->ftb_mtx);
1483
1484 new_fprc = kmem_zalloc(sizeof (fasttrap_proc_t), KM_SLEEP);
1485 new_fprc->ftpc_pid = pid;
1486 new_fprc->ftpc_rcount = 1;
1487 new_fprc->ftpc_acount = 1;
1488#if !defined(sun)
1489 mutex_init(&new_fprc->ftpc_mtx, "fasttrap proc mtx", MUTEX_DEFAULT,
1490 NULL);
1491#endif
1492
1493 mutex_enter(&bucket->ftb_mtx);
1494
1495 /*
1496 * Take another lap through the list to make sure a proc hasn't
1497 * been created for this pid while we weren't under the bucket lock.
1498 */
1499 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
1500 if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) {
1501 mutex_enter(&fprc->ftpc_mtx);
1502 mutex_exit(&bucket->ftb_mtx);
1503 fprc->ftpc_rcount++;
1504 atomic_inc_64(&fprc->ftpc_acount);
1505 ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount);
1506 mutex_exit(&fprc->ftpc_mtx);
1507
1508 kmem_free(new_fprc, sizeof (fasttrap_proc_t));
1509
1510 return (fprc);
1511 }
1512 }
1513
1514 new_fprc->ftpc_next = bucket->ftb_data;
1515 bucket->ftb_data = new_fprc;
1516
1517 mutex_exit(&bucket->ftb_mtx);
1518
1519 return (new_fprc);
1520}
1521
1522static void
1523fasttrap_proc_release(fasttrap_proc_t *proc)
1524{
1525 fasttrap_bucket_t *bucket;
1526 fasttrap_proc_t *fprc, **fprcp;
1527 pid_t pid = proc->ftpc_pid;
1528#if !defined(sun)
1529 fasttrap_scrblock_t *scrblk, *scrblktmp;
1530 fasttrap_scrspace_t *scrspc, *scrspctmp;
1531 struct proc *p;
1532 struct thread *td;
1533#endif
1534
1535 mutex_enter(&proc->ftpc_mtx);
1536
1537 ASSERT(proc->ftpc_rcount != 0);
1538 ASSERT(proc->ftpc_acount <= proc->ftpc_rcount);
1539
1540 if (--proc->ftpc_rcount != 0) {
1541 mutex_exit(&proc->ftpc_mtx);
1542 return;
1543 }
1544
1545#if !defined(sun)
1546 /*
1547 * Free all structures used to manage per-thread scratch space.
1548 */
1549 LIST_FOREACH_SAFE(scrblk, &proc->ftpc_scrblks, ftsb_next,
1550 scrblktmp) {
1551 LIST_REMOVE(scrblk, ftsb_next);
1552 free(scrblk, M_SOLARIS);
1553 }
1554 LIST_FOREACH_SAFE(scrspc, &proc->ftpc_fscr, ftss_next, scrspctmp) {
1555 LIST_REMOVE(scrspc, ftss_next);
1556 free(scrspc, M_SOLARIS);
1557 }
1558 LIST_FOREACH_SAFE(scrspc, &proc->ftpc_ascr, ftss_next, scrspctmp) {
1559 LIST_REMOVE(scrspc, ftss_next);
1560 free(scrspc, M_SOLARIS);
1561 }
1562
1563 if ((p = pfind(pid)) != NULL) {
1564 FOREACH_THREAD_IN_PROC(p, td)
1565 td->t_dtrace_sscr = NULL;
1566 PROC_UNLOCK(p);
1567 }
1568#endif
1569
1570 mutex_exit(&proc->ftpc_mtx);
1571
1572 /*
1573 * There should definitely be no live providers associated with this
1574 * process at this point.
1575 */
1576 ASSERT(proc->ftpc_acount == 0);
1577
1578 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
1579 mutex_enter(&bucket->ftb_mtx);
1580
1581 fprcp = (fasttrap_proc_t **)&bucket->ftb_data;
1582 while ((fprc = *fprcp) != NULL) {
1583 if (fprc == proc)
1584 break;
1585
1586 fprcp = &fprc->ftpc_next;
1587 }
1588
1589 /*
1590 * Something strange has happened if we can't find the proc.
1591 */
1592 ASSERT(fprc != NULL);
1593
1594 *fprcp = fprc->ftpc_next;
1595
1596 mutex_exit(&bucket->ftb_mtx);
1597
1598 kmem_free(fprc, sizeof (fasttrap_proc_t));
1599}
1600
1601/*
1602 * Lookup a fasttrap-managed provider based on its name and associated pid.
1603 * If the pattr argument is non-NULL, this function instantiates the provider
1604 * if it doesn't exist otherwise it returns NULL. The provider is returned
1605 * with its lock held.
1606 */
1607static fasttrap_provider_t *
1608fasttrap_provider_lookup(pid_t pid, const char *name,
1609 const dtrace_pattr_t *pattr)
1610{
1611 fasttrap_provider_t *fp, *new_fp = NULL;
1612 fasttrap_bucket_t *bucket;
1613 char provname[DTRACE_PROVNAMELEN];
1614 proc_t *p;
1615 cred_t *cred;
1616
1617 ASSERT(strlen(name) < sizeof (fp->ftp_name));
1618 ASSERT(pattr != NULL);
1619
1620 bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)];
1621 mutex_enter(&bucket->ftb_mtx);
1622
1623 /*
1624 * Take a lap through the list and return the match if we find it.
1625 */
1626 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
1627 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
1628 !fp->ftp_retired) {
1629 mutex_enter(&fp->ftp_mtx);
1630 mutex_exit(&bucket->ftb_mtx);
1631 return (fp);
1632 }
1633 }
1634
1635 /*
1636 * Drop the bucket lock so we don't try to perform a sleeping
1637 * allocation under it.
1638 */
1639 mutex_exit(&bucket->ftb_mtx);
1640
1641 /*
1642 * Make sure the process exists, isn't a child created as the result
1643 * of a vfork(2), and isn't a zombie (but may be in fork).
1644 */
1645 if ((p = pfind(pid)) == NULL)
1646 return (NULL);
1647
1648 /*
1649 * Increment p_dtrace_probes so that the process knows to inform us
1650 * when it exits or execs. fasttrap_provider_free() decrements this
1651 * when we're done with this provider.
1652 */
1653 p->p_dtrace_probes++;
1654
1655 /*
1656 * Grab the credentials for this process so we have
1657 * something to pass to dtrace_register().
1658 */
1659 PROC_LOCK_ASSERT(p, MA_OWNED);
1660 crhold(p->p_ucred);
1661 cred = p->p_ucred;
1662 PROC_UNLOCK(p);
1663
1664 new_fp = kmem_zalloc(sizeof (fasttrap_provider_t), KM_SLEEP);
1665 new_fp->ftp_pid = pid;
1666 new_fp->ftp_proc = fasttrap_proc_lookup(pid);
1667#if !defined(sun)
1668 mutex_init(&new_fp->ftp_mtx, "provider mtx", MUTEX_DEFAULT, NULL);
1669 mutex_init(&new_fp->ftp_cmtx, "lock on creating", MUTEX_DEFAULT, NULL);
1670#endif
1671
1672 ASSERT(new_fp->ftp_proc != NULL);
1673
1674 mutex_enter(&bucket->ftb_mtx);
1675
1676 /*
1677 * Take another lap through the list to make sure a provider hasn't
1678 * been created for this pid while we weren't under the bucket lock.
1679 */
1680 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
1681 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
1682 !fp->ftp_retired) {
1683 mutex_enter(&fp->ftp_mtx);
1684 mutex_exit(&bucket->ftb_mtx);
1685 fasttrap_provider_free(new_fp);
1686 crfree(cred);
1687 return (fp);
1688 }
1689 }
1690
1691 (void) strcpy(new_fp->ftp_name, name);
1692
1693 /*
1694 * Fail and return NULL if either the provider name is too long
1695 * or we fail to register this new provider with the DTrace
1696 * framework. Note that this is the only place we ever construct
1697 * the full provider name -- we keep it in pieces in the provider
1698 * structure.
1699 */
1700 if (snprintf(provname, sizeof (provname), "%s%u", name, (uint_t)pid) >=
1701 sizeof (provname) ||
1702 dtrace_register(provname, pattr,
1703 DTRACE_PRIV_PROC | DTRACE_PRIV_OWNER | DTRACE_PRIV_ZONEOWNER, cred,
1704 pattr == &pid_attr ? &pid_pops : &usdt_pops, new_fp,
1705 &new_fp->ftp_provid) != 0) {
1706 mutex_exit(&bucket->ftb_mtx);
1707 fasttrap_provider_free(new_fp);
1708 crfree(cred);
1709 return (NULL);
1710 }
1711
1712 new_fp->ftp_next = bucket->ftb_data;
1713 bucket->ftb_data = new_fp;
1714
1715 mutex_enter(&new_fp->ftp_mtx);
1716 mutex_exit(&bucket->ftb_mtx);
1717
1718 crfree(cred);
1719 return (new_fp);
1720}
1721
1722static void
1723fasttrap_provider_free(fasttrap_provider_t *provider)
1724{
1725 pid_t pid = provider->ftp_pid;
1726 proc_t *p;
1727
1728 /*
1729 * There need to be no associated enabled probes, no consumers
1730 * creating probes, and no meta providers referencing this provider.
1731 */
1732 ASSERT(provider->ftp_rcount == 0);
1733 ASSERT(provider->ftp_ccount == 0);
1734 ASSERT(provider->ftp_mcount == 0);
1735
1736 /*
1737 * If this provider hasn't been retired, we need to explicitly drop the
1738 * count of active providers on the associated process structure.
1739 */
1740 if (!provider->ftp_retired) {
1741 atomic_dec_64(&provider->ftp_proc->ftpc_acount);
1742 ASSERT(provider->ftp_proc->ftpc_acount <
1743 provider->ftp_proc->ftpc_rcount);
1744 }
1745
1746 fasttrap_proc_release(provider->ftp_proc);
1747
1748#if !defined(sun)
1749 mutex_destroy(&provider->ftp_mtx);
1750 mutex_destroy(&provider->ftp_cmtx);
1751#endif
1752 kmem_free(provider, sizeof (fasttrap_provider_t));
1753
1754 /*
1755 * Decrement p_dtrace_probes on the process whose provider we're
1756 * freeing. We don't have to worry about clobbering somone else's
1757 * modifications to it because we have locked the bucket that
1758 * corresponds to this process's hash chain in the provider hash
1759 * table. Don't sweat it if we can't find the process.
1760 */
1761 if ((p = pfind(pid)) == NULL) {
1762 return;
1763 }
1764
1765 p->p_dtrace_probes--;
1766#if !defined(sun)
1767 PROC_UNLOCK(p);
1768#endif
1769}
1770
1771static void
1772fasttrap_provider_retire(pid_t pid, const char *name, int mprov)
1773{
1774 fasttrap_provider_t *fp;
1775 fasttrap_bucket_t *bucket;
1776 dtrace_provider_id_t provid;
1777
1778 ASSERT(strlen(name) < sizeof (fp->ftp_name));
1779
1780 bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)];
1781 mutex_enter(&bucket->ftb_mtx);
1782
1783 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
1784 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
1785 !fp->ftp_retired)
1786 break;
1787 }
1788
1789 if (fp == NULL) {
1790 mutex_exit(&bucket->ftb_mtx);
1791 return;
1792 }
1793
1794 mutex_enter(&fp->ftp_mtx);
1795 ASSERT(!mprov || fp->ftp_mcount > 0);
1796 if (mprov && --fp->ftp_mcount != 0) {
1797 mutex_exit(&fp->ftp_mtx);
1798 mutex_exit(&bucket->ftb_mtx);
1799 return;
1800 }
1801
1802 /*
1803 * Mark the provider to be removed in our post-processing step, mark it
1804 * retired, and drop the active count on its proc. Marking it indicates
1805 * that we should try to remove it; setting the retired flag indicates
1806 * that we're done with this provider; dropping the active the proc
1807 * releases our hold, and when this reaches zero (as it will during
1808 * exit or exec) the proc and associated providers become defunct.
1809 *
1810 * We obviously need to take the bucket lock before the provider lock
1811 * to perform the lookup, but we need to drop the provider lock
1812 * before calling into the DTrace framework since we acquire the
1813 * provider lock in callbacks invoked from the DTrace framework. The
1814 * bucket lock therefore protects the integrity of the provider hash
1815 * table.
1816 */
1817 atomic_dec_64(&fp->ftp_proc->ftpc_acount);
1818 ASSERT(fp->ftp_proc->ftpc_acount < fp->ftp_proc->ftpc_rcount);
1819
1820 fp->ftp_retired = 1;
1821 fp->ftp_marked = 1;
1822 provid = fp->ftp_provid;
1823 mutex_exit(&fp->ftp_mtx);
1824
1825 /*
1826 * We don't have to worry about invalidating the same provider twice
1827 * since fasttrap_provider_lookup() will ignore provider that have
1828 * been marked as retired.
1829 */
1830 dtrace_invalidate(provid);
1831
1832 mutex_exit(&bucket->ftb_mtx);
1833
1834 fasttrap_pid_cleanup();
1835}
1836
1837static int
1838fasttrap_uint32_cmp(const void *ap, const void *bp)
1839{
1840 return (*(const uint32_t *)ap - *(const uint32_t *)bp);
1841}
1842
1843static int
1844fasttrap_uint64_cmp(const void *ap, const void *bp)
1845{
1846 return (*(const uint64_t *)ap - *(const uint64_t *)bp);
1847}
1848
1849static int
1850fasttrap_add_probe(fasttrap_probe_spec_t *pdata)
1851{
1852 fasttrap_provider_t *provider;
1853 fasttrap_probe_t *pp;
1854 fasttrap_tracepoint_t *tp;
1855 char *name;
1856 int i, aframes = 0, whack;
1857
1858 /*
1859 * There needs to be at least one desired trace point.
1860 */
1861 if (pdata->ftps_noffs == 0)
1862 return (EINVAL);
1863
1864 switch (pdata->ftps_type) {
1865 case DTFTP_ENTRY:
1866 name = "entry";
1867 aframes = FASTTRAP_ENTRY_AFRAMES;
1868 break;
1869 case DTFTP_RETURN:
1870 name = "return";
1871 aframes = FASTTRAP_RETURN_AFRAMES;
1872 break;
1873 case DTFTP_OFFSETS:
1874 name = NULL;
1875 break;
1876 default:
1877 return (EINVAL);
1878 }
1879
1880 if ((provider = fasttrap_provider_lookup(pdata->ftps_pid,
1881 FASTTRAP_PID_NAME, &pid_attr)) == NULL)
1882 return (ESRCH);
1883
1884 /*
1885 * Increment this reference count to indicate that a consumer is
1886 * actively adding a new probe associated with this provider. This
1887 * prevents the provider from being deleted -- we'll need to check
1888 * for pending deletions when we drop this reference count.
1889 */
1890 provider->ftp_ccount++;
1891 mutex_exit(&provider->ftp_mtx);
1892
1893 /*
1894 * Grab the creation lock to ensure consistency between calls to
1895 * dtrace_probe_lookup() and dtrace_probe_create() in the face of
1896 * other threads creating probes. We must drop the provider lock
1897 * before taking this lock to avoid a three-way deadlock with the
1898 * DTrace framework.
1899 */
1900 mutex_enter(&provider->ftp_cmtx);
1901
1902 if (name == NULL) {
1903 for (i = 0; i < pdata->ftps_noffs; i++) {
1904 char name_str[17];
1905
1906 (void) sprintf(name_str, "%llx",
1907 (unsigned long long)pdata->ftps_offs[i]);
1908
1909 if (dtrace_probe_lookup(provider->ftp_provid,
1910 pdata->ftps_mod, pdata->ftps_func, name_str) != 0)
1911 continue;
1912
1913 atomic_inc_32(&fasttrap_total);
1914
1915 if (fasttrap_total > fasttrap_max) {
1916 atomic_dec_32(&fasttrap_total);
1917 goto no_mem;
1918 }
1919
1920 pp = kmem_zalloc(sizeof (fasttrap_probe_t), KM_SLEEP);
1921
1922 pp->ftp_prov = provider;
1923 pp->ftp_faddr = pdata->ftps_pc;
1924 pp->ftp_fsize = pdata->ftps_size;
1925 pp->ftp_pid = pdata->ftps_pid;
1926 pp->ftp_ntps = 1;
1927
1928 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t),
1929 KM_SLEEP);
1930
1931 tp->ftt_proc = provider->ftp_proc;
1932 tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc;
1933 tp->ftt_pid = pdata->ftps_pid;
1934
1935 pp->ftp_tps[0].fit_tp = tp;
1936 pp->ftp_tps[0].fit_id.fti_probe = pp;
1937 pp->ftp_tps[0].fit_id.fti_ptype = pdata->ftps_type;
1938
1939 pp->ftp_id = dtrace_probe_create(provider->ftp_provid,
1940 pdata->ftps_mod, pdata->ftps_func, name_str,
1941 FASTTRAP_OFFSET_AFRAMES, pp);
1942 }
1943
1944 } else if (dtrace_probe_lookup(provider->ftp_provid, pdata->ftps_mod,
1945 pdata->ftps_func, name) == 0) {
1946 atomic_add_32(&fasttrap_total, pdata->ftps_noffs);
1947
1948 if (fasttrap_total > fasttrap_max) {
1949 atomic_add_32(&fasttrap_total, -pdata->ftps_noffs);
1950 goto no_mem;
1951 }
1952
1953 /*
1954 * Make sure all tracepoint program counter values are unique.
1955 * We later assume that each probe has exactly one tracepoint
1956 * for a given pc.
1957 */
1958 qsort(pdata->ftps_offs, pdata->ftps_noffs,
1959 sizeof (uint64_t), fasttrap_uint64_cmp);
1960 for (i = 1; i < pdata->ftps_noffs; i++) {
1961 if (pdata->ftps_offs[i] > pdata->ftps_offs[i - 1])
1962 continue;
1963
1964 atomic_add_32(&fasttrap_total, -pdata->ftps_noffs);
1965 goto no_mem;
1966 }
1967
1968 ASSERT(pdata->ftps_noffs > 0);
1969 pp = kmem_zalloc(offsetof(fasttrap_probe_t,
1970 ftp_tps[pdata->ftps_noffs]), KM_SLEEP);
1971
1972 pp->ftp_prov = provider;
1973 pp->ftp_faddr = pdata->ftps_pc;
1974 pp->ftp_fsize = pdata->ftps_size;
1975 pp->ftp_pid = pdata->ftps_pid;
1976 pp->ftp_ntps = pdata->ftps_noffs;
1977
1978 for (i = 0; i < pdata->ftps_noffs; i++) {
1979 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t),
1980 KM_SLEEP);
1981
1982 tp->ftt_proc = provider->ftp_proc;
1983 tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc;
1984 tp->ftt_pid = pdata->ftps_pid;
1985
1986 pp->ftp_tps[i].fit_tp = tp;
1987 pp->ftp_tps[i].fit_id.fti_probe = pp;
1988 pp->ftp_tps[i].fit_id.fti_ptype = pdata->ftps_type;
1989 }
1990
1991 pp->ftp_id = dtrace_probe_create(provider->ftp_provid,
1992 pdata->ftps_mod, pdata->ftps_func, name, aframes, pp);
1993 }
1994
1995 mutex_exit(&provider->ftp_cmtx);
1996
1997 /*
1998 * We know that the provider is still valid since we incremented the
1999 * creation reference count. If someone tried to clean up this provider
2000 * while we were using it (e.g. because the process called exec(2) or
2001 * exit(2)), take note of that and try to clean it up now.
2002 */
2003 mutex_enter(&provider->ftp_mtx);
2004 provider->ftp_ccount--;
2005 whack = provider->ftp_retired;
2006 mutex_exit(&provider->ftp_mtx);
2007
2008 if (whack)
2009 fasttrap_pid_cleanup();
2010
2011 return (0);
2012
2013no_mem:
2014 /*
2015 * If we've exhausted the allowable resources, we'll try to remove
2016 * this provider to free some up. This is to cover the case where
2017 * the user has accidentally created many more probes than was
2018 * intended (e.g. pid123:::).
2019 */
2020 mutex_exit(&provider->ftp_cmtx);
2021 mutex_enter(&provider->ftp_mtx);
2022 provider->ftp_ccount--;
2023 provider->ftp_marked = 1;
2024 mutex_exit(&provider->ftp_mtx);
2025
2026 fasttrap_pid_cleanup();
2027
2028 return (ENOMEM);
2029}
2030
2031/*ARGSUSED*/
2032static void *
2033fasttrap_meta_provide(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
2034{
2035 fasttrap_provider_t *provider;
2036
2037 /*
2038 * A 32-bit unsigned integer (like a pid for example) can be
2039 * expressed in 10 or fewer decimal digits. Make sure that we'll
2040 * have enough space for the provider name.
2041 */
2042 if (strlen(dhpv->dthpv_provname) + 10 >=
2043 sizeof (provider->ftp_name)) {
2044 printf("failed to instantiate provider %s: "
2045 "name too long to accomodate pid", dhpv->dthpv_provname);
2046 return (NULL);
2047 }
2048
2049 /*
2050 * Don't let folks spoof the true pid provider.
2051 */
2052 if (strcmp(dhpv->dthpv_provname, FASTTRAP_PID_NAME) == 0) {
2053 printf("failed to instantiate provider %s: "
2054 "%s is an invalid name", dhpv->dthpv_provname,
2055 FASTTRAP_PID_NAME);
2056 return (NULL);
2057 }
2058
2059 /*
2060 * The highest stability class that fasttrap supports is ISA; cap
2061 * the stability of the new provider accordingly.
2062 */
2063 if (dhpv->dthpv_pattr.dtpa_provider.dtat_class > DTRACE_CLASS_ISA)
2064 dhpv->dthpv_pattr.dtpa_provider.dtat_class = DTRACE_CLASS_ISA;
2065 if (dhpv->dthpv_pattr.dtpa_mod.dtat_class > DTRACE_CLASS_ISA)
2066 dhpv->dthpv_pattr.dtpa_mod.dtat_class = DTRACE_CLASS_ISA;
2067 if (dhpv->dthpv_pattr.dtpa_func.dtat_class > DTRACE_CLASS_ISA)
2068 dhpv->dthpv_pattr.dtpa_func.dtat_class = DTRACE_CLASS_ISA;
2069 if (dhpv->dthpv_pattr.dtpa_name.dtat_class > DTRACE_CLASS_ISA)
2070 dhpv->dthpv_pattr.dtpa_name.dtat_class = DTRACE_CLASS_ISA;
2071 if (dhpv->dthpv_pattr.dtpa_args.dtat_class > DTRACE_CLASS_ISA)
2072 dhpv->dthpv_pattr.dtpa_args.dtat_class = DTRACE_CLASS_ISA;
2073
2074 if ((provider = fasttrap_provider_lookup(pid, dhpv->dthpv_provname,
2075 &dhpv->dthpv_pattr)) == NULL) {
2076 printf("failed to instantiate provider %s for "
2077 "process %u", dhpv->dthpv_provname, (uint_t)pid);
2078 return (NULL);
2079 }
2080
2081 /*
2082 * Up the meta provider count so this provider isn't removed until
2083 * the meta provider has been told to remove it.
2084 */
2085 provider->ftp_mcount++;
2086
2087 mutex_exit(&provider->ftp_mtx);
2088
2089 return (provider);
2090}
2091
2092/*ARGSUSED*/
2093static void
2094fasttrap_meta_create_probe(void *arg, void *parg,
2095 dtrace_helper_probedesc_t *dhpb)
2096{
2097 fasttrap_provider_t *provider = parg;
2098 fasttrap_probe_t *pp;
2099 fasttrap_tracepoint_t *tp;
2100 int i, j;
2101 uint32_t ntps;
2102
2103 /*
2104 * Since the meta provider count is non-zero we don't have to worry
2105 * about this provider disappearing.
2106 */
2107 ASSERT(provider->ftp_mcount > 0);
2108
2109 /*
2110 * The offsets must be unique.
2111 */
2112 qsort(dhpb->dthpb_offs, dhpb->dthpb_noffs, sizeof (uint32_t),
2113 fasttrap_uint32_cmp);
2114 for (i = 1; i < dhpb->dthpb_noffs; i++) {
2115 if (dhpb->dthpb_base + dhpb->dthpb_offs[i] <=
2116 dhpb->dthpb_base + dhpb->dthpb_offs[i - 1])
2117 return;
2118 }
2119
2120 qsort(dhpb->dthpb_enoffs, dhpb->dthpb_nenoffs, sizeof (uint32_t),
2121 fasttrap_uint32_cmp);
2122 for (i = 1; i < dhpb->dthpb_nenoffs; i++) {
2123 if (dhpb->dthpb_base + dhpb->dthpb_enoffs[i] <=
2124 dhpb->dthpb_base + dhpb->dthpb_enoffs[i - 1])
2125 return;
2126 }
2127
2128 /*
2129 * Grab the creation lock to ensure consistency between calls to
2130 * dtrace_probe_lookup() and dtrace_probe_create() in the face of
2131 * other threads creating probes.
2132 */
2133 mutex_enter(&provider->ftp_cmtx);
2134
2135 if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod,
2136 dhpb->dthpb_func, dhpb->dthpb_name) != 0) {
2137 mutex_exit(&provider->ftp_cmtx);
2138 return;
2139 }
2140
2141 ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs;
2142 ASSERT(ntps > 0);
2143
2144 atomic_add_32(&fasttrap_total, ntps);
2145
2146 if (fasttrap_total > fasttrap_max) {
2147 atomic_add_32(&fasttrap_total, -ntps);
2148 mutex_exit(&provider->ftp_cmtx);
2149 return;
2150 }
2151
2152 pp = kmem_zalloc(offsetof(fasttrap_probe_t, ftp_tps[ntps]), KM_SLEEP);
2153
2154 pp->ftp_prov = provider;
2155 pp->ftp_pid = provider->ftp_pid;
2156 pp->ftp_ntps = ntps;
2157 pp->ftp_nargs = dhpb->dthpb_xargc;
2158 pp->ftp_xtypes = dhpb->dthpb_xtypes;
2159 pp->ftp_ntypes = dhpb->dthpb_ntypes;
2160
2161 /*
2162 * First create a tracepoint for each actual point of interest.
2163 */
2164 for (i = 0; i < dhpb->dthpb_noffs; i++) {
2165 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP);
2166
2167 tp->ftt_proc = provider->ftp_proc;
2168 tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_offs[i];
2169 tp->ftt_pid = provider->ftp_pid;
2170
2171 pp->ftp_tps[i].fit_tp = tp;
2172 pp->ftp_tps[i].fit_id.fti_probe = pp;
2173#ifdef __sparc
2174 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_POST_OFFSETS;
2175#else
2176 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_OFFSETS;
2177#endif
2178 }
2179
2180 /*
2181 * Then create a tracepoint for each is-enabled point.
2182 */
2183 for (j = 0; i < ntps; i++, j++) {
2184 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP);
2185
2186 tp->ftt_proc = provider->ftp_proc;
2187 tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_enoffs[j];
2188 tp->ftt_pid = provider->ftp_pid;
2189
2190 pp->ftp_tps[i].fit_tp = tp;
2191 pp->ftp_tps[i].fit_id.fti_probe = pp;
2192 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_IS_ENABLED;
2193 }
2194
2195 /*
2196 * If the arguments are shuffled around we set the argument remapping
2197 * table. Later, when the probe fires, we only remap the arguments
2198 * if the table is non-NULL.
2199 */
2200 for (i = 0; i < dhpb->dthpb_xargc; i++) {
2201 if (dhpb->dthpb_args[i] != i) {
2202 pp->ftp_argmap = dhpb->dthpb_args;
2203 break;
2204 }
2205 }
2206
2207 /*
2208 * The probe is fully constructed -- register it with DTrace.
2209 */
2210 pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod,
2211 dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp);
2212
2213 mutex_exit(&provider->ftp_cmtx);
2214}
2215
2216/*ARGSUSED*/
2217static void
2218fasttrap_meta_remove(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
2219{
2220 /*
2221 * Clean up the USDT provider. There may be active consumers of the
2222 * provider busy adding probes, no damage will actually befall the
2223 * provider until that count has dropped to zero. This just puts
2224 * the provider on death row.
2225 */
2226 fasttrap_provider_retire(pid, dhpv->dthpv_provname, 1);
2227}
2228
2229static dtrace_mops_t fasttrap_mops = {
2230 fasttrap_meta_create_probe,
2231 fasttrap_meta_provide,
2232 fasttrap_meta_remove
2233};
2234
2235/*ARGSUSED*/
2236static int
2237fasttrap_open(struct cdev *dev __unused, int oflags __unused,
2238 int devtype __unused, struct thread *td __unused)
2239{
2240 return (0);
2241}
2242
2243/*ARGSUSED*/
2244static int
2245fasttrap_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int fflag,
2246 struct thread *td)
2247{
2248#ifdef notyet
2249 struct kinfo_proc kp;
2250 const cred_t *cr = td->td_ucred;
2251#endif
2252 if (!dtrace_attached())
2253 return (EAGAIN);
2254
2255 if (cmd == FASTTRAPIOC_MAKEPROBE) {
2256 fasttrap_probe_spec_t *uprobe = *(fasttrap_probe_spec_t **)arg;
2257 fasttrap_probe_spec_t *probe;
2258 uint64_t noffs;
2259 size_t size;
2260 int ret, err;
2261
2262 if (copyin(&uprobe->ftps_noffs, &noffs,
2263 sizeof (uprobe->ftps_noffs)))
2264 return (EFAULT);
2265
2266 /*
2267 * Probes must have at least one tracepoint.
2268 */
2269 if (noffs == 0)
2270 return (EINVAL);
2271
2272 size = sizeof (fasttrap_probe_spec_t) +
2273 sizeof (probe->ftps_offs[0]) * (noffs - 1);
2274
2275 if (size > 1024 * 1024)
2276 return (ENOMEM);
2277
2278 probe = kmem_alloc(size, KM_SLEEP);
2279
2280 if (copyin(uprobe, probe, size) != 0 ||
2281 probe->ftps_noffs != noffs) {
2282 kmem_free(probe, size);
2283 return (EFAULT);
2284 }
2285
2286 /*
2287 * Verify that the function and module strings contain no
2288 * funny characters.
2289 */
2290 if (u8_validate(probe->ftps_func, strlen(probe->ftps_func),
2291 NULL, U8_VALIDATE_ENTIRE, &err) < 0) {
2292 ret = EINVAL;
2293 goto err;
2294 }
2295
2296 if (u8_validate(probe->ftps_mod, strlen(probe->ftps_mod),
2297 NULL, U8_VALIDATE_ENTIRE, &err) < 0) {
2298 ret = EINVAL;
2299 goto err;
2300 }
2301
2302#ifdef notyet
2303 if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {
2304 proc_t *p;
2305 pid_t pid = probe->ftps_pid;
2306
2307#if defined(sun)
2308 mutex_enter(&pidlock);
2309#endif
2310 /*
2311 * Report an error if the process doesn't exist
2312 * or is actively being birthed.
2313 */
2314 sx_slock(&proctree_lock);
2315 p = pfind(pid);
2316 if (p)
2317 fill_kinfo_proc(p, &kp);
2318 sx_sunlock(&proctree_lock);
2319 if (p == NULL || kp.ki_stat == SIDL) {
2320#if defined(sun)
2321 mutex_exit(&pidlock);
2322#endif
2323 return (ESRCH);
2324 }
2325#if defined(sun)
2326 mutex_enter(&p->p_lock);
2327 mutex_exit(&pidlock);
2328#else
2329 PROC_LOCK_ASSERT(p, MA_OWNED);
2330#endif
2331
2332#ifdef notyet
2333 if ((ret = priv_proc_cred_perm(cr, p, NULL,
2334 VREAD | VWRITE)) != 0) {
2335#if defined(sun)
2336 mutex_exit(&p->p_lock);
2337#else
2338 PROC_UNLOCK(p);
2339#endif
2340 return (ret);
2341 }
2342#endif /* notyet */
2343#if defined(sun)
2344 mutex_exit(&p->p_lock);
2345#else
2346 PROC_UNLOCK(p);
2347#endif
2348 }
2349#endif /* notyet */
2350
2351 ret = fasttrap_add_probe(probe);
2352err:
2353 kmem_free(probe, size);
2354
2355 return (ret);
2356
2357 } else if (cmd == FASTTRAPIOC_GETINSTR) {
2358 fasttrap_instr_query_t instr;
2359 fasttrap_tracepoint_t *tp;
2360 uint_t index;
2361#if defined(sun)
2362 int ret;
2363#endif
2364
2365#if defined(sun)
2366 if (copyin((void *)arg, &instr, sizeof (instr)) != 0)
2367 return (EFAULT);
2368#endif
2369
2370#ifdef notyet
2371 if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {
2372 proc_t *p;
2373 pid_t pid = instr.ftiq_pid;
2374
2375#if defined(sun)
2376 mutex_enter(&pidlock);
2377#endif
2378 /*
2379 * Report an error if the process doesn't exist
2380 * or is actively being birthed.
2381 */
2382 sx_slock(&proctree_lock);
2383 p = pfind(pid);
2384 if (p)
2385 fill_kinfo_proc(p, &kp);
2386 sx_sunlock(&proctree_lock);
2387 if (p == NULL || kp.ki_stat == SIDL) {
2388#if defined(sun)
2389 mutex_exit(&pidlock);
2390#endif
2391 return (ESRCH);
2392 }
2393#if defined(sun)
2394 mutex_enter(&p->p_lock);
2395 mutex_exit(&pidlock);
2396#else
2397 PROC_LOCK_ASSERT(p, MA_OWNED);
2398#endif
2399
2400#ifdef notyet
2401 if ((ret = priv_proc_cred_perm(cr, p, NULL,
2402 VREAD)) != 0) {
2403#if defined(sun)
2404 mutex_exit(&p->p_lock);
2405#else
2406 PROC_UNLOCK(p);
2407#endif
2408 return (ret);
2409 }
2410#endif /* notyet */
2411
2412#if defined(sun)
2413 mutex_exit(&p->p_lock);
2414#else
2415 PROC_UNLOCK(p);
2416#endif
2417 }
2418#endif /* notyet */
2419
2420 index = FASTTRAP_TPOINTS_INDEX(instr.ftiq_pid, instr.ftiq_pc);
2421
2422 mutex_enter(&fasttrap_tpoints.fth_table[index].ftb_mtx);
2423 tp = fasttrap_tpoints.fth_table[index].ftb_data;
2424 while (tp != NULL) {
2425 if (instr.ftiq_pid == tp->ftt_pid &&
2426 instr.ftiq_pc == tp->ftt_pc &&
2427 tp->ftt_proc->ftpc_acount != 0)
2428 break;
2429
2430 tp = tp->ftt_next;
2431 }
2432
2433 if (tp == NULL) {
2434 mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx);
2435 return (ENOENT);
2436 }
2437
2438 bcopy(&tp->ftt_instr, &instr.ftiq_instr,
2439 sizeof (instr.ftiq_instr));
2440 mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx);
2441
2442 if (copyout(&instr, (void *)arg, sizeof (instr)) != 0)
2443 return (EFAULT);
2444
2445 return (0);
2446 }
2447
2448 return (EINVAL);
2449}
2450
2451static int
2452fasttrap_load(void)
2453{
2454 ulong_t nent;
2455 int i, ret;
2456
2457 /* Create the /dev/dtrace/fasttrap entry. */
2458 fasttrap_cdev = make_dev(&fasttrap_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
2459 "dtrace/fasttrap");
2460
2461 mtx_init(&fasttrap_cleanup_mtx, "fasttrap clean", "dtrace", MTX_DEF);
2462 mutex_init(&fasttrap_count_mtx, "fasttrap count mtx", MUTEX_DEFAULT,
2463 NULL);
2464
2465#if defined(sun)
2466 fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
2467 "fasttrap-max-probes", FASTTRAP_MAX_DEFAULT);
2468#else
2469 fasttrap_max = FASTTRAP_MAX_DEFAULT;
2470#endif
2471 fasttrap_total = 0;
2472
2473 /*
2474 * Conjure up the tracepoints hashtable...
2475 */
2476#if defined(sun)
2477 nent = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
2478 "fasttrap-hash-size", FASTTRAP_TPOINTS_DEFAULT_SIZE);
2479#else
2480 nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
2481#endif
2482
2483 if (nent == 0 || nent > 0x1000000)
2484 nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
2485
| 24 */
25
26/*
27 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
28 * Use is subject to license terms.
29 */
30
31/*
32 * Copyright (c) 2013, Joyent, Inc. All rights reserved.
33 */
34
35#include <sys/atomic.h>
36#include <sys/errno.h>
37#include <sys/stat.h>
38#include <sys/modctl.h>
39#include <sys/conf.h>
40#include <sys/systm.h>
41#if defined(sun)
42#include <sys/ddi.h>
43#endif
44#include <sys/sunddi.h>
45#include <sys/cpuvar.h>
46#include <sys/kmem.h>
47#if defined(sun)
48#include <sys/strsubr.h>
49#endif
50#include <sys/fasttrap.h>
51#include <sys/fasttrap_impl.h>
52#include <sys/fasttrap_isa.h>
53#include <sys/dtrace.h>
54#include <sys/dtrace_impl.h>
55#include <sys/sysmacros.h>
56#include <sys/proc.h>
57#include <sys/policy.h>
58#if defined(sun)
59#include <util/qsort.h>
60#endif
61#include <sys/mutex.h>
62#include <sys/kernel.h>
63#if !defined(sun)
64#include <sys/dtrace_bsd.h>
65#include <sys/eventhandler.h>
66#include <sys/u8_textprep.h>
67#include <sys/user.h>
68#include <vm/vm.h>
69#include <vm/pmap.h>
70#include <vm/vm_map.h>
71#include <vm/vm_param.h>
72#include <cddl/dev/dtrace/dtrace_cddl.h>
73#endif
74
75/*
76 * User-Land Trap-Based Tracing
77 * ----------------------------
78 *
79 * The fasttrap provider allows DTrace consumers to instrument any user-level
80 * instruction to gather data; this includes probes with semantic
81 * signifigance like entry and return as well as simple offsets into the
82 * function. While the specific techniques used are very ISA specific, the
83 * methodology is generalizable to any architecture.
84 *
85 *
86 * The General Methodology
87 * -----------------------
88 *
89 * With the primary goal of tracing every user-land instruction and the
90 * limitation that we can't trust user space so don't want to rely on much
91 * information there, we begin by replacing the instructions we want to trace
92 * with trap instructions. Each instruction we overwrite is saved into a hash
93 * table keyed by process ID and pc address. When we enter the kernel due to
94 * this trap instruction, we need the effects of the replaced instruction to
95 * appear to have occurred before we proceed with the user thread's
96 * execution.
97 *
98 * Each user level thread is represented by a ulwp_t structure which is
99 * always easily accessible through a register. The most basic way to produce
100 * the effects of the instruction we replaced is to copy that instruction out
101 * to a bit of scratch space reserved in the user thread's ulwp_t structure
102 * (a sort of kernel-private thread local storage), set the PC to that
103 * scratch space and single step. When we reenter the kernel after single
104 * stepping the instruction we must then adjust the PC to point to what would
105 * normally be the next instruction. Of course, special care must be taken
106 * for branches and jumps, but these represent such a small fraction of any
107 * instruction set that writing the code to emulate these in the kernel is
108 * not too difficult.
109 *
110 * Return probes may require several tracepoints to trace every return site,
111 * and, conversely, each tracepoint may activate several probes (the entry
112 * and offset 0 probes, for example). To solve this muliplexing problem,
113 * tracepoints contain lists of probes to activate and probes contain lists
114 * of tracepoints to enable. If a probe is activated, it adds its ID to
115 * existing tracepoints or creates new ones as necessary.
116 *
117 * Most probes are activated _before_ the instruction is executed, but return
118 * probes are activated _after_ the effects of the last instruction of the
119 * function are visible. Return probes must be fired _after_ we have
120 * single-stepped the instruction whereas all other probes are fired
121 * beforehand.
122 *
123 *
124 * Lock Ordering
125 * -------------
126 *
127 * The lock ordering below -- both internally and with respect to the DTrace
128 * framework -- is a little tricky and bears some explanation. Each provider
129 * has a lock (ftp_mtx) that protects its members including reference counts
130 * for enabled probes (ftp_rcount), consumers actively creating probes
131 * (ftp_ccount) and USDT consumers (ftp_mcount); all three prevent a provider
132 * from being freed. A provider is looked up by taking the bucket lock for the
133 * provider hash table, and is returned with its lock held. The provider lock
134 * may be taken in functions invoked by the DTrace framework, but may not be
135 * held while calling functions in the DTrace framework.
136 *
137 * To ensure consistency over multiple calls to the DTrace framework, the
138 * creation lock (ftp_cmtx) should be held. Naturally, the creation lock may
139 * not be taken when holding the provider lock as that would create a cyclic
140 * lock ordering. In situations where one would naturally take the provider
141 * lock and then the creation lock, we instead up a reference count to prevent
142 * the provider from disappearing, drop the provider lock, and acquire the
143 * creation lock.
144 *
145 * Briefly:
146 * bucket lock before provider lock
147 * DTrace before provider lock
148 * creation lock before DTrace
149 * never hold the provider lock and creation lock simultaneously
150 */
151
152static d_open_t fasttrap_open;
153static d_ioctl_t fasttrap_ioctl;
154
155static struct cdevsw fasttrap_cdevsw = {
156 .d_version = D_VERSION,
157 .d_open = fasttrap_open,
158 .d_ioctl = fasttrap_ioctl,
159 .d_name = "fasttrap",
160};
161static struct cdev *fasttrap_cdev;
162static dtrace_meta_provider_id_t fasttrap_meta_id;
163
164static struct proc *fasttrap_cleanup_proc;
165static struct mtx fasttrap_cleanup_mtx;
166static uint_t fasttrap_cleanup_work, fasttrap_cleanup_drain, fasttrap_cleanup_cv;
167
168/*
169 * Generation count on modifications to the global tracepoint lookup table.
170 */
171static volatile uint64_t fasttrap_mod_gen;
172
173/*
174 * When the fasttrap provider is loaded, fasttrap_max is set to either
175 * FASTTRAP_MAX_DEFAULT or the value for fasttrap-max-probes in the
176 * fasttrap.conf file. Each time a probe is created, fasttrap_total is
177 * incremented by the number of tracepoints that may be associated with that
178 * probe; fasttrap_total is capped at fasttrap_max.
179 */
180#define FASTTRAP_MAX_DEFAULT 250000
181static uint32_t fasttrap_max;
182static uint32_t fasttrap_total;
183
184/*
185 * Copyright (c) 2011, Joyent, Inc. All rights reserved.
186 */
187
188#define FASTTRAP_TPOINTS_DEFAULT_SIZE 0x4000
189#define FASTTRAP_PROVIDERS_DEFAULT_SIZE 0x100
190#define FASTTRAP_PROCS_DEFAULT_SIZE 0x100
191
192#define FASTTRAP_PID_NAME "pid"
193
194fasttrap_hash_t fasttrap_tpoints;
195static fasttrap_hash_t fasttrap_provs;
196static fasttrap_hash_t fasttrap_procs;
197
198static uint64_t fasttrap_pid_count; /* pid ref count */
199static kmutex_t fasttrap_count_mtx; /* lock on ref count */
200
201#define FASTTRAP_ENABLE_FAIL 1
202#define FASTTRAP_ENABLE_PARTIAL 2
203
204static int fasttrap_tracepoint_enable(proc_t *, fasttrap_probe_t *, uint_t);
205static void fasttrap_tracepoint_disable(proc_t *, fasttrap_probe_t *, uint_t);
206
207static fasttrap_provider_t *fasttrap_provider_lookup(pid_t, const char *,
208 const dtrace_pattr_t *);
209static void fasttrap_provider_retire(pid_t, const char *, int);
210static void fasttrap_provider_free(fasttrap_provider_t *);
211
212static fasttrap_proc_t *fasttrap_proc_lookup(pid_t);
213static void fasttrap_proc_release(fasttrap_proc_t *);
214
215#if !defined(sun)
216static void fasttrap_thread_dtor(void *, struct thread *);
217#endif
218
219#define FASTTRAP_PROVS_INDEX(pid, name) \
220 ((fasttrap_hash_str(name) + (pid)) & fasttrap_provs.fth_mask)
221
222#define FASTTRAP_PROCS_INDEX(pid) ((pid) & fasttrap_procs.fth_mask)
223
224#if !defined(sun)
225static kmutex_t fasttrap_cpuc_pid_lock[MAXCPU];
226static eventhandler_tag fasttrap_thread_dtor_tag;
227#endif
228
229static int
230fasttrap_highbit(ulong_t i)
231{
232 int h = 1;
233
234 if (i == 0)
235 return (0);
236#ifdef _LP64
237 if (i & 0xffffffff00000000ul) {
238 h += 32; i >>= 32;
239 }
240#endif
241 if (i & 0xffff0000) {
242 h += 16; i >>= 16;
243 }
244 if (i & 0xff00) {
245 h += 8; i >>= 8;
246 }
247 if (i & 0xf0) {
248 h += 4; i >>= 4;
249 }
250 if (i & 0xc) {
251 h += 2; i >>= 2;
252 }
253 if (i & 0x2) {
254 h += 1;
255 }
256 return (h);
257}
258
259static uint_t
260fasttrap_hash_str(const char *p)
261{
262 unsigned int g;
263 uint_t hval = 0;
264
265 while (*p) {
266 hval = (hval << 4) + *p++;
267 if ((g = (hval & 0xf0000000)) != 0)
268 hval ^= g >> 24;
269 hval &= ~g;
270 }
271 return (hval);
272}
273
274void
275fasttrap_sigtrap(proc_t *p, kthread_t *t, uintptr_t pc)
276{
277#if defined(sun)
278 sigqueue_t *sqp = kmem_zalloc(sizeof (sigqueue_t), KM_SLEEP);
279
280 sqp->sq_info.si_signo = SIGTRAP;
281 sqp->sq_info.si_code = TRAP_DTRACE;
282 sqp->sq_info.si_addr = (caddr_t)pc;
283
284 mutex_enter(&p->p_lock);
285 sigaddqa(p, t, sqp);
286 mutex_exit(&p->p_lock);
287
288 if (t != NULL)
289 aston(t);
290#else
291 ksiginfo_t *ksi = kmem_zalloc(sizeof (ksiginfo_t), KM_SLEEP);
292
293 ksiginfo_init(ksi);
294 ksi->ksi_signo = SIGTRAP;
295 ksi->ksi_code = TRAP_DTRACE;
296 ksi->ksi_addr = (caddr_t)pc;
297 PROC_LOCK(p);
298 (void) tdksignal(t, SIGTRAP, ksi);
299 PROC_UNLOCK(p);
300#endif
301}
302
303#if !defined(sun)
304/*
305 * Obtain a chunk of scratch space in the address space of the target process.
306 */
307fasttrap_scrspace_t *
308fasttrap_scraddr(struct thread *td, fasttrap_proc_t *fprc)
309{
310 fasttrap_scrblock_t *scrblk;
311 fasttrap_scrspace_t *scrspc;
312 struct proc *p;
313 vm_offset_t addr;
314 int error, i;
315
316 scrspc = NULL;
317 if (td->t_dtrace_sscr != NULL) {
318 /* If the thread already has scratch space, we're done. */
319 scrspc = (fasttrap_scrspace_t *)td->t_dtrace_sscr;
320 return (scrspc);
321 }
322
323 p = td->td_proc;
324
325 mutex_enter(&fprc->ftpc_mtx);
326 if (LIST_EMPTY(&fprc->ftpc_fscr)) {
327 /*
328 * No scratch space is available, so we'll map a new scratch
329 * space block into the traced process' address space.
330 */
331 addr = 0;
332 error = vm_map_find(&p->p_vmspace->vm_map, NULL, 0, &addr,
333 FASTTRAP_SCRBLOCK_SIZE, 0, VMFS_ANY_SPACE, VM_PROT_ALL,
334 VM_PROT_ALL, 0);
335 if (error != KERN_SUCCESS)
336 goto done;
337
338 scrblk = malloc(sizeof(*scrblk), M_SOLARIS, M_WAITOK);
339 scrblk->ftsb_addr = addr;
340 LIST_INSERT_HEAD(&fprc->ftpc_scrblks, scrblk, ftsb_next);
341
342 /*
343 * Carve the block up into chunks and put them on the free list.
344 */
345 for (i = 0;
346 i < FASTTRAP_SCRBLOCK_SIZE / FASTTRAP_SCRSPACE_SIZE; i++) {
347 scrspc = malloc(sizeof(*scrspc), M_SOLARIS, M_WAITOK);
348 scrspc->ftss_addr = addr +
349 i * FASTTRAP_SCRSPACE_SIZE;
350 LIST_INSERT_HEAD(&fprc->ftpc_fscr, scrspc,
351 ftss_next);
352 }
353 }
354
355 /*
356 * Take the first scratch chunk off the free list, put it on the
357 * allocated list, and return its address.
358 */
359 scrspc = LIST_FIRST(&fprc->ftpc_fscr);
360 LIST_REMOVE(scrspc, ftss_next);
361 LIST_INSERT_HEAD(&fprc->ftpc_ascr, scrspc, ftss_next);
362
363 /*
364 * This scratch space is reserved for use by td until the thread exits.
365 */
366 td->t_dtrace_sscr = scrspc;
367
368done:
369 mutex_exit(&fprc->ftpc_mtx);
370
371 return (scrspc);
372}
373
374/*
375 * Return any allocated per-thread scratch space chunks back to the process'
376 * free list.
377 */
378static void
379fasttrap_thread_dtor(void *arg __unused, struct thread *td)
380{
381 fasttrap_bucket_t *bucket;
382 fasttrap_proc_t *fprc;
383 fasttrap_scrspace_t *scrspc;
384 pid_t pid;
385
386 if (td->t_dtrace_sscr == NULL)
387 return;
388
389 pid = td->td_proc->p_pid;
390 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
391 fprc = NULL;
392
393 /* Look up the fasttrap process handle for this process. */
394 mutex_enter(&bucket->ftb_mtx);
395 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
396 if (fprc->ftpc_pid == pid) {
397 mutex_enter(&fprc->ftpc_mtx);
398 mutex_exit(&bucket->ftb_mtx);
399 break;
400 }
401 }
402 if (fprc == NULL) {
403 mutex_exit(&bucket->ftb_mtx);
404 return;
405 }
406
407 scrspc = (fasttrap_scrspace_t *)td->t_dtrace_sscr;
408 LIST_REMOVE(scrspc, ftss_next);
409 LIST_INSERT_HEAD(&fprc->ftpc_fscr, scrspc, ftss_next);
410
411 mutex_exit(&fprc->ftpc_mtx);
412}
413#endif
414
415/*
416 * This function ensures that no threads are actively using the memory
417 * associated with probes that were formerly live.
418 */
419static void
420fasttrap_mod_barrier(uint64_t gen)
421{
422 int i;
423
424 if (gen < fasttrap_mod_gen)
425 return;
426
427 fasttrap_mod_gen++;
428
429 CPU_FOREACH(i) {
430 mutex_enter(&fasttrap_cpuc_pid_lock[i]);
431 mutex_exit(&fasttrap_cpuc_pid_lock[i]);
432 }
433}
434
435/*
436 * This function performs asynchronous cleanup of fasttrap providers. The
437 * Solaris implementation of this mechanism use a timeout that's activated in
438 * fasttrap_pid_cleanup(), but this doesn't work in FreeBSD: one may sleep while
439 * holding the DTrace mutexes, but it is unsafe to sleep in a callout handler.
440 * Thus we use a dedicated process to perform the cleanup when requested.
441 */
442/*ARGSUSED*/
443static void
444fasttrap_pid_cleanup_cb(void *data)
445{
446 fasttrap_provider_t **fpp, *fp;
447 fasttrap_bucket_t *bucket;
448 dtrace_provider_id_t provid;
449 int i, later = 0, rval;
450
451 mtx_lock(&fasttrap_cleanup_mtx);
452 while (!fasttrap_cleanup_drain || later > 0) {
453 fasttrap_cleanup_work = 0;
454 mtx_unlock(&fasttrap_cleanup_mtx);
455
456 later = 0;
457
458 /*
459 * Iterate over all the providers trying to remove the marked
460 * ones. If a provider is marked but not retired, we just
461 * have to take a crack at removing it -- it's no big deal if
462 * we can't.
463 */
464 for (i = 0; i < fasttrap_provs.fth_nent; i++) {
465 bucket = &fasttrap_provs.fth_table[i];
466 mutex_enter(&bucket->ftb_mtx);
467 fpp = (fasttrap_provider_t **)&bucket->ftb_data;
468
469 while ((fp = *fpp) != NULL) {
470 if (!fp->ftp_marked) {
471 fpp = &fp->ftp_next;
472 continue;
473 }
474
475 mutex_enter(&fp->ftp_mtx);
476
477 /*
478 * If this provider has consumers actively
479 * creating probes (ftp_ccount) or is a USDT
480 * provider (ftp_mcount), we can't unregister
481 * or even condense.
482 */
483 if (fp->ftp_ccount != 0 ||
484 fp->ftp_mcount != 0) {
485 mutex_exit(&fp->ftp_mtx);
486 fp->ftp_marked = 0;
487 continue;
488 }
489
490 if (!fp->ftp_retired || fp->ftp_rcount != 0)
491 fp->ftp_marked = 0;
492
493 mutex_exit(&fp->ftp_mtx);
494
495 /*
496 * If we successfully unregister this
497 * provider we can remove it from the hash
498 * chain and free the memory. If our attempt
499 * to unregister fails and this is a retired
500 * provider, increment our flag to try again
501 * pretty soon. If we've consumed more than
502 * half of our total permitted number of
503 * probes call dtrace_condense() to try to
504 * clean out the unenabled probes.
505 */
506 provid = fp->ftp_provid;
507 if ((rval = dtrace_unregister(provid)) != 0) {
508 if (fasttrap_total > fasttrap_max / 2)
509 (void) dtrace_condense(provid);
510
511 if (rval == EAGAIN)
512 fp->ftp_marked = 1;
513
514 later += fp->ftp_marked;
515 fpp = &fp->ftp_next;
516 } else {
517 *fpp = fp->ftp_next;
518 fasttrap_provider_free(fp);
519 }
520 }
521 mutex_exit(&bucket->ftb_mtx);
522 }
523 mtx_lock(&fasttrap_cleanup_mtx);
524
525 /*
526 * If we were unable to retire a provider, try again after a
527 * second. This situation can occur in certain circumstances
528 * where providers cannot be unregistered even though they have
529 * no probes enabled because of an execution of dtrace -l or
530 * something similar.
531 */
532 if (later > 0 || fasttrap_cleanup_work ||
533 fasttrap_cleanup_drain) {
534 mtx_unlock(&fasttrap_cleanup_mtx);
535 pause("ftclean", hz);
536 mtx_lock(&fasttrap_cleanup_mtx);
537 } else
538 mtx_sleep(&fasttrap_cleanup_cv, &fasttrap_cleanup_mtx,
539 0, "ftcl", 0);
540 }
541
542 /*
543 * Wake up the thread in fasttrap_unload() now that we're done.
544 */
545 wakeup(&fasttrap_cleanup_drain);
546 mtx_unlock(&fasttrap_cleanup_mtx);
547
548 kthread_exit();
549}
550
551/*
552 * Activates the asynchronous cleanup mechanism.
553 */
554static void
555fasttrap_pid_cleanup(void)
556{
557
558 mtx_lock(&fasttrap_cleanup_mtx);
559 if (!fasttrap_cleanup_work) {
560 fasttrap_cleanup_work = 1;
561 wakeup(&fasttrap_cleanup_cv);
562 }
563 mtx_unlock(&fasttrap_cleanup_mtx);
564}
565
566/*
567 * This is called from cfork() via dtrace_fasttrap_fork(). The child
568 * process's address space is (roughly) a copy of the parent process's so
569 * we have to remove all the instrumentation we had previously enabled in the
570 * parent.
571 */
572static void
573fasttrap_fork(proc_t *p, proc_t *cp)
574{
575#if !defined(sun)
576 fasttrap_scrblock_t *scrblk;
577 fasttrap_proc_t *fprc = NULL;
578#endif
579 pid_t ppid = p->p_pid;
580 int i;
581
582#if defined(sun)
583 ASSERT(curproc == p);
584 ASSERT(p->p_proc_flag & P_PR_LOCK);
585#else
586 PROC_LOCK_ASSERT(p, MA_OWNED);
587#endif
588#if defined(sun)
589 ASSERT(p->p_dtrace_count > 0);
590#else
591 if (p->p_dtrace_helpers) {
592 /*
593 * dtrace_helpers_duplicate() allocates memory.
594 */
595 _PHOLD(cp);
596 PROC_UNLOCK(p);
597 PROC_UNLOCK(cp);
598 dtrace_helpers_duplicate(p, cp);
599 PROC_LOCK(cp);
600 PROC_LOCK(p);
601 _PRELE(cp);
602 }
603 /*
604 * This check is purposely here instead of in kern_fork.c because,
605 * for legal resons, we cannot include the dtrace_cddl.h header
606 * inside kern_fork.c and insert if-clause there.
607 */
608 if (p->p_dtrace_count == 0)
609 return;
610#endif
611 ASSERT(cp->p_dtrace_count == 0);
612
613 /*
614 * This would be simpler and faster if we maintained per-process
615 * hash tables of enabled tracepoints. It could, however, potentially
616 * slow down execution of a tracepoint since we'd need to go
617 * through two levels of indirection. In the future, we should
618 * consider either maintaining per-process ancillary lists of
619 * enabled tracepoints or hanging a pointer to a per-process hash
620 * table of enabled tracepoints off the proc structure.
621 */
622
623 /*
624 * We don't have to worry about the child process disappearing
625 * because we're in fork().
626 */
627#if defined(sun)
628 mtx_lock_spin(&cp->p_slock);
629 sprlock_proc(cp);
630 mtx_unlock_spin(&cp->p_slock);
631#else
632 /*
633 * fasttrap_tracepoint_remove() expects the child process to be
634 * unlocked and the VM then expects curproc to be unlocked.
635 */
636 _PHOLD(cp);
637 PROC_UNLOCK(cp);
638 PROC_UNLOCK(p);
639#endif
640
641 /*
642 * Iterate over every tracepoint looking for ones that belong to the
643 * parent process, and remove each from the child process.
644 */
645 for (i = 0; i < fasttrap_tpoints.fth_nent; i++) {
646 fasttrap_tracepoint_t *tp;
647 fasttrap_bucket_t *bucket = &fasttrap_tpoints.fth_table[i];
648
649 mutex_enter(&bucket->ftb_mtx);
650 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
651 if (tp->ftt_pid == ppid &&
652 tp->ftt_proc->ftpc_acount != 0) {
653 int ret = fasttrap_tracepoint_remove(cp, tp);
654 ASSERT(ret == 0);
655
656 /*
657 * The count of active providers can only be
658 * decremented (i.e. to zero) during exec,
659 * exit, and removal of a meta provider so it
660 * should be impossible to drop the count
661 * mid-fork.
662 */
663 ASSERT(tp->ftt_proc->ftpc_acount != 0);
664#if !defined(sun)
665 fprc = tp->ftt_proc;
666#endif
667 }
668 }
669 mutex_exit(&bucket->ftb_mtx);
670
671#if !defined(sun)
672 /*
673 * Unmap any scratch space inherited from the parent's address
674 * space.
675 */
676 if (fprc != NULL) {
677 mutex_enter(&fprc->ftpc_mtx);
678 LIST_FOREACH(scrblk, &fprc->ftpc_scrblks, ftsb_next) {
679 vm_map_remove(&cp->p_vmspace->vm_map,
680 scrblk->ftsb_addr,
681 scrblk->ftsb_addr + FASTTRAP_SCRBLOCK_SIZE);
682 }
683 mutex_exit(&fprc->ftpc_mtx);
684 }
685#endif
686 }
687
688#if defined(sun)
689 mutex_enter(&cp->p_lock);
690 sprunlock(cp);
691#else
692 PROC_LOCK(p);
693 PROC_LOCK(cp);
694 _PRELE(cp);
695#endif
696}
697
698/*
699 * This is called from proc_exit() or from exec_common() if p_dtrace_probes
700 * is set on the proc structure to indicate that there is a pid provider
701 * associated with this process.
702 */
703static void
704fasttrap_exec_exit(proc_t *p)
705{
706#if !defined(sun)
707 struct thread *td;
708#endif
709
710#if defined(sun)
711 ASSERT(p == curproc);
712#else
713 PROC_LOCK_ASSERT(p, MA_OWNED);
714 _PHOLD(p);
715 /*
716 * Since struct threads may be recycled, we cannot rely on t_dtrace_sscr
717 * fields to be zeroed by kdtrace_thread_ctor. Thus we must zero it
718 * ourselves when a process exits.
719 */
720 FOREACH_THREAD_IN_PROC(p, td)
721 td->t_dtrace_sscr = NULL;
722 PROC_UNLOCK(p);
723#endif
724
725 /*
726 * We clean up the pid provider for this process here; user-land
727 * static probes are handled by the meta-provider remove entry point.
728 */
729 fasttrap_provider_retire(p->p_pid, FASTTRAP_PID_NAME, 0);
730#if !defined(sun)
731 if (p->p_dtrace_helpers)
732 dtrace_helpers_destroy(p);
733 PROC_LOCK(p);
734 _PRELE(p);
735#endif
736}
737
738
739/*ARGSUSED*/
740static void
741fasttrap_pid_provide(void *arg, dtrace_probedesc_t *desc)
742{
743 /*
744 * There are no "default" pid probes.
745 */
746}
747
748static int
749fasttrap_tracepoint_enable(proc_t *p, fasttrap_probe_t *probe, uint_t index)
750{
751 fasttrap_tracepoint_t *tp, *new_tp = NULL;
752 fasttrap_bucket_t *bucket;
753 fasttrap_id_t *id;
754 pid_t pid;
755 uintptr_t pc;
756
757 ASSERT(index < probe->ftp_ntps);
758
759 pid = probe->ftp_pid;
760 pc = probe->ftp_tps[index].fit_tp->ftt_pc;
761 id = &probe->ftp_tps[index].fit_id;
762
763 ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid);
764
765#if defined(sun)
766 ASSERT(!(p->p_flag & SVFORK));
767#endif
768
769 /*
770 * Before we make any modifications, make sure we've imposed a barrier
771 * on the generation in which this probe was last modified.
772 */
773 fasttrap_mod_barrier(probe->ftp_gen);
774
775 bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
776
777 /*
778 * If the tracepoint has already been enabled, just add our id to the
779 * list of interested probes. This may be our second time through
780 * this path in which case we'll have constructed the tracepoint we'd
781 * like to install. If we can't find a match, and have an allocated
782 * tracepoint ready to go, enable that one now.
783 *
784 * A tracepoint whose process is defunct is also considered defunct.
785 */
786again:
787 mutex_enter(&bucket->ftb_mtx);
788 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
789 /*
790 * Note that it's safe to access the active count on the
791 * associated proc structure because we know that at least one
792 * provider (this one) will still be around throughout this
793 * operation.
794 */
795 if (tp->ftt_pid != pid || tp->ftt_pc != pc ||
796 tp->ftt_proc->ftpc_acount == 0)
797 continue;
798
799 /*
800 * Now that we've found a matching tracepoint, it would be
801 * a decent idea to confirm that the tracepoint is still
802 * enabled and the trap instruction hasn't been overwritten.
803 * Since this is a little hairy, we'll punt for now.
804 */
805
806 /*
807 * This can't be the first interested probe. We don't have
808 * to worry about another thread being in the midst of
809 * deleting this tracepoint (which would be the only valid
810 * reason for a tracepoint to have no interested probes)
811 * since we're holding P_PR_LOCK for this process.
812 */
813 ASSERT(tp->ftt_ids != NULL || tp->ftt_retids != NULL);
814
815 switch (id->fti_ptype) {
816 case DTFTP_ENTRY:
817 case DTFTP_OFFSETS:
818 case DTFTP_IS_ENABLED:
819 id->fti_next = tp->ftt_ids;
820 membar_producer();
821 tp->ftt_ids = id;
822 membar_producer();
823 break;
824
825 case DTFTP_RETURN:
826 case DTFTP_POST_OFFSETS:
827 id->fti_next = tp->ftt_retids;
828 membar_producer();
829 tp->ftt_retids = id;
830 membar_producer();
831 break;
832
833 default:
834 ASSERT(0);
835 }
836
837 mutex_exit(&bucket->ftb_mtx);
838
839 if (new_tp != NULL) {
840 new_tp->ftt_ids = NULL;
841 new_tp->ftt_retids = NULL;
842 }
843
844 return (0);
845 }
846
847 /*
848 * If we have a good tracepoint ready to go, install it now while
849 * we have the lock held and no one can screw with us.
850 */
851 if (new_tp != NULL) {
852 int rc = 0;
853
854 new_tp->ftt_next = bucket->ftb_data;
855 membar_producer();
856 bucket->ftb_data = new_tp;
857 membar_producer();
858 mutex_exit(&bucket->ftb_mtx);
859
860 /*
861 * Activate the tracepoint in the ISA-specific manner.
862 * If this fails, we need to report the failure, but
863 * indicate that this tracepoint must still be disabled
864 * by calling fasttrap_tracepoint_disable().
865 */
866 if (fasttrap_tracepoint_install(p, new_tp) != 0)
867 rc = FASTTRAP_ENABLE_PARTIAL;
868
869 /*
870 * Increment the count of the number of tracepoints active in
871 * the victim process.
872 */
873#if defined(sun)
874 ASSERT(p->p_proc_flag & P_PR_LOCK);
875#endif
876 p->p_dtrace_count++;
877
878 return (rc);
879 }
880
881 mutex_exit(&bucket->ftb_mtx);
882
883 /*
884 * Initialize the tracepoint that's been preallocated with the probe.
885 */
886 new_tp = probe->ftp_tps[index].fit_tp;
887
888 ASSERT(new_tp->ftt_pid == pid);
889 ASSERT(new_tp->ftt_pc == pc);
890 ASSERT(new_tp->ftt_proc == probe->ftp_prov->ftp_proc);
891 ASSERT(new_tp->ftt_ids == NULL);
892 ASSERT(new_tp->ftt_retids == NULL);
893
894 switch (id->fti_ptype) {
895 case DTFTP_ENTRY:
896 case DTFTP_OFFSETS:
897 case DTFTP_IS_ENABLED:
898 id->fti_next = NULL;
899 new_tp->ftt_ids = id;
900 break;
901
902 case DTFTP_RETURN:
903 case DTFTP_POST_OFFSETS:
904 id->fti_next = NULL;
905 new_tp->ftt_retids = id;
906 break;
907
908 default:
909 ASSERT(0);
910 }
911
912 /*
913 * If the ISA-dependent initialization goes to plan, go back to the
914 * beginning and try to install this freshly made tracepoint.
915 */
916 if (fasttrap_tracepoint_init(p, new_tp, pc, id->fti_ptype) == 0)
917 goto again;
918
919 new_tp->ftt_ids = NULL;
920 new_tp->ftt_retids = NULL;
921
922 return (FASTTRAP_ENABLE_FAIL);
923}
924
925static void
926fasttrap_tracepoint_disable(proc_t *p, fasttrap_probe_t *probe, uint_t index)
927{
928 fasttrap_bucket_t *bucket;
929 fasttrap_provider_t *provider = probe->ftp_prov;
930 fasttrap_tracepoint_t **pp, *tp;
931 fasttrap_id_t *id, **idp = NULL;
932 pid_t pid;
933 uintptr_t pc;
934
935 ASSERT(index < probe->ftp_ntps);
936
937 pid = probe->ftp_pid;
938 pc = probe->ftp_tps[index].fit_tp->ftt_pc;
939 id = &probe->ftp_tps[index].fit_id;
940
941 ASSERT(probe->ftp_tps[index].fit_tp->ftt_pid == pid);
942
943 /*
944 * Find the tracepoint and make sure that our id is one of the
945 * ones registered with it.
946 */
947 bucket = &fasttrap_tpoints.fth_table[FASTTRAP_TPOINTS_INDEX(pid, pc)];
948 mutex_enter(&bucket->ftb_mtx);
949 for (tp = bucket->ftb_data; tp != NULL; tp = tp->ftt_next) {
950 if (tp->ftt_pid == pid && tp->ftt_pc == pc &&
951 tp->ftt_proc == provider->ftp_proc)
952 break;
953 }
954
955 /*
956 * If we somehow lost this tracepoint, we're in a world of hurt.
957 */
958 ASSERT(tp != NULL);
959
960 switch (id->fti_ptype) {
961 case DTFTP_ENTRY:
962 case DTFTP_OFFSETS:
963 case DTFTP_IS_ENABLED:
964 ASSERT(tp->ftt_ids != NULL);
965 idp = &tp->ftt_ids;
966 break;
967
968 case DTFTP_RETURN:
969 case DTFTP_POST_OFFSETS:
970 ASSERT(tp->ftt_retids != NULL);
971 idp = &tp->ftt_retids;
972 break;
973
974 default:
975 ASSERT(0);
976 }
977
978 while ((*idp)->fti_probe != probe) {
979 idp = &(*idp)->fti_next;
980 ASSERT(*idp != NULL);
981 }
982
983 id = *idp;
984 *idp = id->fti_next;
985 membar_producer();
986
987 ASSERT(id->fti_probe == probe);
988
989 /*
990 * If there are other registered enablings of this tracepoint, we're
991 * all done, but if this was the last probe assocated with this
992 * this tracepoint, we need to remove and free it.
993 */
994 if (tp->ftt_ids != NULL || tp->ftt_retids != NULL) {
995
996 /*
997 * If the current probe's tracepoint is in use, swap it
998 * for an unused tracepoint.
999 */
1000 if (tp == probe->ftp_tps[index].fit_tp) {
1001 fasttrap_probe_t *tmp_probe;
1002 fasttrap_tracepoint_t **tmp_tp;
1003 uint_t tmp_index;
1004
1005 if (tp->ftt_ids != NULL) {
1006 tmp_probe = tp->ftt_ids->fti_probe;
1007 /* LINTED - alignment */
1008 tmp_index = FASTTRAP_ID_INDEX(tp->ftt_ids);
1009 tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp;
1010 } else {
1011 tmp_probe = tp->ftt_retids->fti_probe;
1012 /* LINTED - alignment */
1013 tmp_index = FASTTRAP_ID_INDEX(tp->ftt_retids);
1014 tmp_tp = &tmp_probe->ftp_tps[tmp_index].fit_tp;
1015 }
1016
1017 ASSERT(*tmp_tp != NULL);
1018 ASSERT(*tmp_tp != probe->ftp_tps[index].fit_tp);
1019 ASSERT((*tmp_tp)->ftt_ids == NULL);
1020 ASSERT((*tmp_tp)->ftt_retids == NULL);
1021
1022 probe->ftp_tps[index].fit_tp = *tmp_tp;
1023 *tmp_tp = tp;
1024 }
1025
1026 mutex_exit(&bucket->ftb_mtx);
1027
1028 /*
1029 * Tag the modified probe with the generation in which it was
1030 * changed.
1031 */
1032 probe->ftp_gen = fasttrap_mod_gen;
1033 return;
1034 }
1035
1036 mutex_exit(&bucket->ftb_mtx);
1037
1038 /*
1039 * We can't safely remove the tracepoint from the set of active
1040 * tracepoints until we've actually removed the fasttrap instruction
1041 * from the process's text. We can, however, operate on this
1042 * tracepoint secure in the knowledge that no other thread is going to
1043 * be looking at it since we hold P_PR_LOCK on the process if it's
1044 * live or we hold the provider lock on the process if it's dead and
1045 * gone.
1046 */
1047
1048 /*
1049 * We only need to remove the actual instruction if we're looking
1050 * at an existing process
1051 */
1052 if (p != NULL) {
1053 /*
1054 * If we fail to restore the instruction we need to kill
1055 * this process since it's in a completely unrecoverable
1056 * state.
1057 */
1058 if (fasttrap_tracepoint_remove(p, tp) != 0)
1059 fasttrap_sigtrap(p, NULL, pc);
1060
1061 /*
1062 * Decrement the count of the number of tracepoints active
1063 * in the victim process.
1064 */
1065#if defined(sun)
1066 ASSERT(p->p_proc_flag & P_PR_LOCK);
1067#endif
1068 p->p_dtrace_count--;
1069 }
1070
1071 /*
1072 * Remove the probe from the hash table of active tracepoints.
1073 */
1074 mutex_enter(&bucket->ftb_mtx);
1075 pp = (fasttrap_tracepoint_t **)&bucket->ftb_data;
1076 ASSERT(*pp != NULL);
1077 while (*pp != tp) {
1078 pp = &(*pp)->ftt_next;
1079 ASSERT(*pp != NULL);
1080 }
1081
1082 *pp = tp->ftt_next;
1083 membar_producer();
1084
1085 mutex_exit(&bucket->ftb_mtx);
1086
1087 /*
1088 * Tag the modified probe with the generation in which it was changed.
1089 */
1090 probe->ftp_gen = fasttrap_mod_gen;
1091}
1092
1093static void
1094fasttrap_enable_callbacks(void)
1095{
1096 /*
1097 * We don't have to play the rw lock game here because we're
1098 * providing something rather than taking something away --
1099 * we can be sure that no threads have tried to follow this
1100 * function pointer yet.
1101 */
1102 mutex_enter(&fasttrap_count_mtx);
1103 if (fasttrap_pid_count == 0) {
1104 ASSERT(dtrace_pid_probe_ptr == NULL);
1105 ASSERT(dtrace_return_probe_ptr == NULL);
1106 dtrace_pid_probe_ptr = &fasttrap_pid_probe;
1107 dtrace_return_probe_ptr = &fasttrap_return_probe;
1108 }
1109 ASSERT(dtrace_pid_probe_ptr == &fasttrap_pid_probe);
1110 ASSERT(dtrace_return_probe_ptr == &fasttrap_return_probe);
1111 fasttrap_pid_count++;
1112 mutex_exit(&fasttrap_count_mtx);
1113}
1114
1115static void
1116fasttrap_disable_callbacks(void)
1117{
1118#if defined(sun)
1119 ASSERT(MUTEX_HELD(&cpu_lock));
1120#endif
1121
1122
1123 mutex_enter(&fasttrap_count_mtx);
1124 ASSERT(fasttrap_pid_count > 0);
1125 fasttrap_pid_count--;
1126 if (fasttrap_pid_count == 0) {
1127#if defined(sun)
1128 cpu_t *cur, *cpu = CPU;
1129
1130 for (cur = cpu->cpu_next_onln; cur != cpu;
1131 cur = cur->cpu_next_onln) {
1132 rw_enter(&cur->cpu_ft_lock, RW_WRITER);
1133 }
1134#endif
1135 dtrace_pid_probe_ptr = NULL;
1136 dtrace_return_probe_ptr = NULL;
1137#if defined(sun)
1138 for (cur = cpu->cpu_next_onln; cur != cpu;
1139 cur = cur->cpu_next_onln) {
1140 rw_exit(&cur->cpu_ft_lock);
1141 }
1142#endif
1143 }
1144 mutex_exit(&fasttrap_count_mtx);
1145}
1146
1147/*ARGSUSED*/
1148static void
1149fasttrap_pid_enable(void *arg, dtrace_id_t id, void *parg)
1150{
1151 fasttrap_probe_t *probe = parg;
1152 proc_t *p = NULL;
1153 int i, rc;
1154
1155 ASSERT(probe != NULL);
1156 ASSERT(!probe->ftp_enabled);
1157 ASSERT(id == probe->ftp_id);
1158#if defined(sun)
1159 ASSERT(MUTEX_HELD(&cpu_lock));
1160#endif
1161
1162 /*
1163 * Increment the count of enabled probes on this probe's provider;
1164 * the provider can't go away while the probe still exists. We
1165 * must increment this even if we aren't able to properly enable
1166 * this probe.
1167 */
1168 mutex_enter(&probe->ftp_prov->ftp_mtx);
1169 probe->ftp_prov->ftp_rcount++;
1170 mutex_exit(&probe->ftp_prov->ftp_mtx);
1171
1172 /*
1173 * If this probe's provider is retired (meaning it was valid in a
1174 * previously exec'ed incarnation of this address space), bail out. The
1175 * provider can't go away while we're in this code path.
1176 */
1177 if (probe->ftp_prov->ftp_retired)
1178 return;
1179
1180 /*
1181 * If we can't find the process, it may be that we're in the context of
1182 * a fork in which the traced process is being born and we're copying
1183 * USDT probes. Otherwise, the process is gone so bail.
1184 */
1185#if defined(sun)
1186 if ((p = sprlock(probe->ftp_pid)) == NULL) {
1187 if ((curproc->p_flag & SFORKING) == 0)
1188 return;
1189
1190 mutex_enter(&pidlock);
1191 p = prfind(probe->ftp_pid);
1192
1193 /*
1194 * Confirm that curproc is indeed forking the process in which
1195 * we're trying to enable probes.
1196 */
1197 ASSERT(p != NULL);
1198 ASSERT(p->p_parent == curproc);
1199 ASSERT(p->p_stat == SIDL);
1200
1201 mutex_enter(&p->p_lock);
1202 mutex_exit(&pidlock);
1203
1204 sprlock_proc(p);
1205 }
1206
1207 ASSERT(!(p->p_flag & SVFORK));
1208 mutex_exit(&p->p_lock);
1209#else
1210 if ((p = pfind(probe->ftp_pid)) == NULL)
1211 return;
1212#endif
1213
1214 /*
1215 * We have to enable the trap entry point before any user threads have
1216 * the chance to execute the trap instruction we're about to place
1217 * in their process's text.
1218 */
1219#ifdef __FreeBSD__
1220 /*
1221 * pfind() returns a locked process.
1222 */
1223 _PHOLD(p);
1224 PROC_UNLOCK(p);
1225#endif
1226 fasttrap_enable_callbacks();
1227
1228 /*
1229 * Enable all the tracepoints and add this probe's id to each
1230 * tracepoint's list of active probes.
1231 */
1232 for (i = 0; i < probe->ftp_ntps; i++) {
1233 if ((rc = fasttrap_tracepoint_enable(p, probe, i)) != 0) {
1234 /*
1235 * If enabling the tracepoint failed completely,
1236 * we don't have to disable it; if the failure
1237 * was only partial we must disable it.
1238 */
1239 if (rc == FASTTRAP_ENABLE_FAIL)
1240 i--;
1241 else
1242 ASSERT(rc == FASTTRAP_ENABLE_PARTIAL);
1243
1244 /*
1245 * Back up and pull out all the tracepoints we've
1246 * created so far for this probe.
1247 */
1248 while (i >= 0) {
1249 fasttrap_tracepoint_disable(p, probe, i);
1250 i--;
1251 }
1252
1253#if defined(sun)
1254 mutex_enter(&p->p_lock);
1255 sprunlock(p);
1256#else
1257 PRELE(p);
1258#endif
1259
1260 /*
1261 * Since we're not actually enabling this probe,
1262 * drop our reference on the trap table entry.
1263 */
1264 fasttrap_disable_callbacks();
1265 return;
1266 }
1267 }
1268#if defined(sun)
1269 mutex_enter(&p->p_lock);
1270 sprunlock(p);
1271#else
1272 PRELE(p);
1273#endif
1274
1275 probe->ftp_enabled = 1;
1276}
1277
1278/*ARGSUSED*/
1279static void
1280fasttrap_pid_disable(void *arg, dtrace_id_t id, void *parg)
1281{
1282 fasttrap_probe_t *probe = parg;
1283 fasttrap_provider_t *provider = probe->ftp_prov;
1284 proc_t *p;
1285 int i, whack = 0;
1286
1287 ASSERT(id == probe->ftp_id);
1288
1289 mutex_enter(&provider->ftp_mtx);
1290
1291 /*
1292 * We won't be able to acquire a /proc-esque lock on the process
1293 * iff the process is dead and gone. In this case, we rely on the
1294 * provider lock as a point of mutual exclusion to prevent other
1295 * DTrace consumers from disabling this probe.
1296 */
1297 if ((p = pfind(probe->ftp_pid)) != NULL) {
1298#ifdef __FreeBSD__
1299 _PHOLD(p);
1300 PROC_UNLOCK(p);
1301#endif
1302 }
1303
1304 /*
1305 * Disable all the associated tracepoints (for fully enabled probes).
1306 */
1307 if (probe->ftp_enabled) {
1308 for (i = 0; i < probe->ftp_ntps; i++) {
1309 fasttrap_tracepoint_disable(p, probe, i);
1310 }
1311 }
1312
1313 ASSERT(provider->ftp_rcount > 0);
1314 provider->ftp_rcount--;
1315
1316 if (p != NULL) {
1317 /*
1318 * Even though we may not be able to remove it entirely, we
1319 * mark this retired provider to get a chance to remove some
1320 * of the associated probes.
1321 */
1322 if (provider->ftp_retired && !provider->ftp_marked)
1323 whack = provider->ftp_marked = 1;
1324 mutex_exit(&provider->ftp_mtx);
1325 } else {
1326 /*
1327 * If the process is dead, we're just waiting for the
1328 * last probe to be disabled to be able to free it.
1329 */
1330 if (provider->ftp_rcount == 0 && !provider->ftp_marked)
1331 whack = provider->ftp_marked = 1;
1332 mutex_exit(&provider->ftp_mtx);
1333 }
1334
1335 if (whack)
1336 fasttrap_pid_cleanup();
1337
1338#ifdef __FreeBSD__
1339 if (p != NULL)
1340 PRELE(p);
1341#endif
1342 if (!probe->ftp_enabled)
1343 return;
1344
1345 probe->ftp_enabled = 0;
1346
1347#if defined(sun)
1348 ASSERT(MUTEX_HELD(&cpu_lock));
1349#endif
1350 fasttrap_disable_callbacks();
1351}
1352
1353/*ARGSUSED*/
1354static void
1355fasttrap_pid_getargdesc(void *arg, dtrace_id_t id, void *parg,
1356 dtrace_argdesc_t *desc)
1357{
1358 fasttrap_probe_t *probe = parg;
1359 char *str;
1360 int i, ndx;
1361
1362 desc->dtargd_native[0] = '\0';
1363 desc->dtargd_xlate[0] = '\0';
1364
1365 if (probe->ftp_prov->ftp_retired != 0 ||
1366 desc->dtargd_ndx >= probe->ftp_nargs) {
1367 desc->dtargd_ndx = DTRACE_ARGNONE;
1368 return;
1369 }
1370
1371 ndx = (probe->ftp_argmap != NULL) ?
1372 probe->ftp_argmap[desc->dtargd_ndx] : desc->dtargd_ndx;
1373
1374 str = probe->ftp_ntypes;
1375 for (i = 0; i < ndx; i++) {
1376 str += strlen(str) + 1;
1377 }
1378
1379 ASSERT(strlen(str + 1) < sizeof (desc->dtargd_native));
1380 (void) strcpy(desc->dtargd_native, str);
1381
1382 if (probe->ftp_xtypes == NULL)
1383 return;
1384
1385 str = probe->ftp_xtypes;
1386 for (i = 0; i < desc->dtargd_ndx; i++) {
1387 str += strlen(str) + 1;
1388 }
1389
1390 ASSERT(strlen(str + 1) < sizeof (desc->dtargd_xlate));
1391 (void) strcpy(desc->dtargd_xlate, str);
1392}
1393
1394/*ARGSUSED*/
1395static void
1396fasttrap_pid_destroy(void *arg, dtrace_id_t id, void *parg)
1397{
1398 fasttrap_probe_t *probe = parg;
1399 int i;
1400 size_t size;
1401
1402 ASSERT(probe != NULL);
1403 ASSERT(!probe->ftp_enabled);
1404 ASSERT(fasttrap_total >= probe->ftp_ntps);
1405
1406 atomic_add_32(&fasttrap_total, -probe->ftp_ntps);
1407 size = offsetof(fasttrap_probe_t, ftp_tps[probe->ftp_ntps]);
1408
1409 if (probe->ftp_gen + 1 >= fasttrap_mod_gen)
1410 fasttrap_mod_barrier(probe->ftp_gen);
1411
1412 for (i = 0; i < probe->ftp_ntps; i++) {
1413 kmem_free(probe->ftp_tps[i].fit_tp,
1414 sizeof (fasttrap_tracepoint_t));
1415 }
1416
1417 kmem_free(probe, size);
1418}
1419
1420
1421static const dtrace_pattr_t pid_attr = {
1422{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
1423{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
1424{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
1425{ DTRACE_STABILITY_EVOLVING, DTRACE_STABILITY_EVOLVING, DTRACE_CLASS_ISA },
1426{ DTRACE_STABILITY_PRIVATE, DTRACE_STABILITY_PRIVATE, DTRACE_CLASS_UNKNOWN },
1427};
1428
1429static dtrace_pops_t pid_pops = {
1430 fasttrap_pid_provide,
1431 NULL,
1432 fasttrap_pid_enable,
1433 fasttrap_pid_disable,
1434 NULL,
1435 NULL,
1436 fasttrap_pid_getargdesc,
1437 fasttrap_pid_getarg,
1438 NULL,
1439 fasttrap_pid_destroy
1440};
1441
1442static dtrace_pops_t usdt_pops = {
1443 fasttrap_pid_provide,
1444 NULL,
1445 fasttrap_pid_enable,
1446 fasttrap_pid_disable,
1447 NULL,
1448 NULL,
1449 fasttrap_pid_getargdesc,
1450 fasttrap_usdt_getarg,
1451 NULL,
1452 fasttrap_pid_destroy
1453};
1454
1455static fasttrap_proc_t *
1456fasttrap_proc_lookup(pid_t pid)
1457{
1458 fasttrap_bucket_t *bucket;
1459 fasttrap_proc_t *fprc, *new_fprc;
1460
1461
1462 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
1463 mutex_enter(&bucket->ftb_mtx);
1464
1465 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
1466 if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) {
1467 mutex_enter(&fprc->ftpc_mtx);
1468 mutex_exit(&bucket->ftb_mtx);
1469 fprc->ftpc_rcount++;
1470 atomic_inc_64(&fprc->ftpc_acount);
1471 ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount);
1472 mutex_exit(&fprc->ftpc_mtx);
1473
1474 return (fprc);
1475 }
1476 }
1477
1478 /*
1479 * Drop the bucket lock so we don't try to perform a sleeping
1480 * allocation under it.
1481 */
1482 mutex_exit(&bucket->ftb_mtx);
1483
1484 new_fprc = kmem_zalloc(sizeof (fasttrap_proc_t), KM_SLEEP);
1485 new_fprc->ftpc_pid = pid;
1486 new_fprc->ftpc_rcount = 1;
1487 new_fprc->ftpc_acount = 1;
1488#if !defined(sun)
1489 mutex_init(&new_fprc->ftpc_mtx, "fasttrap proc mtx", MUTEX_DEFAULT,
1490 NULL);
1491#endif
1492
1493 mutex_enter(&bucket->ftb_mtx);
1494
1495 /*
1496 * Take another lap through the list to make sure a proc hasn't
1497 * been created for this pid while we weren't under the bucket lock.
1498 */
1499 for (fprc = bucket->ftb_data; fprc != NULL; fprc = fprc->ftpc_next) {
1500 if (fprc->ftpc_pid == pid && fprc->ftpc_acount != 0) {
1501 mutex_enter(&fprc->ftpc_mtx);
1502 mutex_exit(&bucket->ftb_mtx);
1503 fprc->ftpc_rcount++;
1504 atomic_inc_64(&fprc->ftpc_acount);
1505 ASSERT(fprc->ftpc_acount <= fprc->ftpc_rcount);
1506 mutex_exit(&fprc->ftpc_mtx);
1507
1508 kmem_free(new_fprc, sizeof (fasttrap_proc_t));
1509
1510 return (fprc);
1511 }
1512 }
1513
1514 new_fprc->ftpc_next = bucket->ftb_data;
1515 bucket->ftb_data = new_fprc;
1516
1517 mutex_exit(&bucket->ftb_mtx);
1518
1519 return (new_fprc);
1520}
1521
1522static void
1523fasttrap_proc_release(fasttrap_proc_t *proc)
1524{
1525 fasttrap_bucket_t *bucket;
1526 fasttrap_proc_t *fprc, **fprcp;
1527 pid_t pid = proc->ftpc_pid;
1528#if !defined(sun)
1529 fasttrap_scrblock_t *scrblk, *scrblktmp;
1530 fasttrap_scrspace_t *scrspc, *scrspctmp;
1531 struct proc *p;
1532 struct thread *td;
1533#endif
1534
1535 mutex_enter(&proc->ftpc_mtx);
1536
1537 ASSERT(proc->ftpc_rcount != 0);
1538 ASSERT(proc->ftpc_acount <= proc->ftpc_rcount);
1539
1540 if (--proc->ftpc_rcount != 0) {
1541 mutex_exit(&proc->ftpc_mtx);
1542 return;
1543 }
1544
1545#if !defined(sun)
1546 /*
1547 * Free all structures used to manage per-thread scratch space.
1548 */
1549 LIST_FOREACH_SAFE(scrblk, &proc->ftpc_scrblks, ftsb_next,
1550 scrblktmp) {
1551 LIST_REMOVE(scrblk, ftsb_next);
1552 free(scrblk, M_SOLARIS);
1553 }
1554 LIST_FOREACH_SAFE(scrspc, &proc->ftpc_fscr, ftss_next, scrspctmp) {
1555 LIST_REMOVE(scrspc, ftss_next);
1556 free(scrspc, M_SOLARIS);
1557 }
1558 LIST_FOREACH_SAFE(scrspc, &proc->ftpc_ascr, ftss_next, scrspctmp) {
1559 LIST_REMOVE(scrspc, ftss_next);
1560 free(scrspc, M_SOLARIS);
1561 }
1562
1563 if ((p = pfind(pid)) != NULL) {
1564 FOREACH_THREAD_IN_PROC(p, td)
1565 td->t_dtrace_sscr = NULL;
1566 PROC_UNLOCK(p);
1567 }
1568#endif
1569
1570 mutex_exit(&proc->ftpc_mtx);
1571
1572 /*
1573 * There should definitely be no live providers associated with this
1574 * process at this point.
1575 */
1576 ASSERT(proc->ftpc_acount == 0);
1577
1578 bucket = &fasttrap_procs.fth_table[FASTTRAP_PROCS_INDEX(pid)];
1579 mutex_enter(&bucket->ftb_mtx);
1580
1581 fprcp = (fasttrap_proc_t **)&bucket->ftb_data;
1582 while ((fprc = *fprcp) != NULL) {
1583 if (fprc == proc)
1584 break;
1585
1586 fprcp = &fprc->ftpc_next;
1587 }
1588
1589 /*
1590 * Something strange has happened if we can't find the proc.
1591 */
1592 ASSERT(fprc != NULL);
1593
1594 *fprcp = fprc->ftpc_next;
1595
1596 mutex_exit(&bucket->ftb_mtx);
1597
1598 kmem_free(fprc, sizeof (fasttrap_proc_t));
1599}
1600
1601/*
1602 * Lookup a fasttrap-managed provider based on its name and associated pid.
1603 * If the pattr argument is non-NULL, this function instantiates the provider
1604 * if it doesn't exist otherwise it returns NULL. The provider is returned
1605 * with its lock held.
1606 */
1607static fasttrap_provider_t *
1608fasttrap_provider_lookup(pid_t pid, const char *name,
1609 const dtrace_pattr_t *pattr)
1610{
1611 fasttrap_provider_t *fp, *new_fp = NULL;
1612 fasttrap_bucket_t *bucket;
1613 char provname[DTRACE_PROVNAMELEN];
1614 proc_t *p;
1615 cred_t *cred;
1616
1617 ASSERT(strlen(name) < sizeof (fp->ftp_name));
1618 ASSERT(pattr != NULL);
1619
1620 bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)];
1621 mutex_enter(&bucket->ftb_mtx);
1622
1623 /*
1624 * Take a lap through the list and return the match if we find it.
1625 */
1626 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
1627 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
1628 !fp->ftp_retired) {
1629 mutex_enter(&fp->ftp_mtx);
1630 mutex_exit(&bucket->ftb_mtx);
1631 return (fp);
1632 }
1633 }
1634
1635 /*
1636 * Drop the bucket lock so we don't try to perform a sleeping
1637 * allocation under it.
1638 */
1639 mutex_exit(&bucket->ftb_mtx);
1640
1641 /*
1642 * Make sure the process exists, isn't a child created as the result
1643 * of a vfork(2), and isn't a zombie (but may be in fork).
1644 */
1645 if ((p = pfind(pid)) == NULL)
1646 return (NULL);
1647
1648 /*
1649 * Increment p_dtrace_probes so that the process knows to inform us
1650 * when it exits or execs. fasttrap_provider_free() decrements this
1651 * when we're done with this provider.
1652 */
1653 p->p_dtrace_probes++;
1654
1655 /*
1656 * Grab the credentials for this process so we have
1657 * something to pass to dtrace_register().
1658 */
1659 PROC_LOCK_ASSERT(p, MA_OWNED);
1660 crhold(p->p_ucred);
1661 cred = p->p_ucred;
1662 PROC_UNLOCK(p);
1663
1664 new_fp = kmem_zalloc(sizeof (fasttrap_provider_t), KM_SLEEP);
1665 new_fp->ftp_pid = pid;
1666 new_fp->ftp_proc = fasttrap_proc_lookup(pid);
1667#if !defined(sun)
1668 mutex_init(&new_fp->ftp_mtx, "provider mtx", MUTEX_DEFAULT, NULL);
1669 mutex_init(&new_fp->ftp_cmtx, "lock on creating", MUTEX_DEFAULT, NULL);
1670#endif
1671
1672 ASSERT(new_fp->ftp_proc != NULL);
1673
1674 mutex_enter(&bucket->ftb_mtx);
1675
1676 /*
1677 * Take another lap through the list to make sure a provider hasn't
1678 * been created for this pid while we weren't under the bucket lock.
1679 */
1680 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
1681 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
1682 !fp->ftp_retired) {
1683 mutex_enter(&fp->ftp_mtx);
1684 mutex_exit(&bucket->ftb_mtx);
1685 fasttrap_provider_free(new_fp);
1686 crfree(cred);
1687 return (fp);
1688 }
1689 }
1690
1691 (void) strcpy(new_fp->ftp_name, name);
1692
1693 /*
1694 * Fail and return NULL if either the provider name is too long
1695 * or we fail to register this new provider with the DTrace
1696 * framework. Note that this is the only place we ever construct
1697 * the full provider name -- we keep it in pieces in the provider
1698 * structure.
1699 */
1700 if (snprintf(provname, sizeof (provname), "%s%u", name, (uint_t)pid) >=
1701 sizeof (provname) ||
1702 dtrace_register(provname, pattr,
1703 DTRACE_PRIV_PROC | DTRACE_PRIV_OWNER | DTRACE_PRIV_ZONEOWNER, cred,
1704 pattr == &pid_attr ? &pid_pops : &usdt_pops, new_fp,
1705 &new_fp->ftp_provid) != 0) {
1706 mutex_exit(&bucket->ftb_mtx);
1707 fasttrap_provider_free(new_fp);
1708 crfree(cred);
1709 return (NULL);
1710 }
1711
1712 new_fp->ftp_next = bucket->ftb_data;
1713 bucket->ftb_data = new_fp;
1714
1715 mutex_enter(&new_fp->ftp_mtx);
1716 mutex_exit(&bucket->ftb_mtx);
1717
1718 crfree(cred);
1719 return (new_fp);
1720}
1721
1722static void
1723fasttrap_provider_free(fasttrap_provider_t *provider)
1724{
1725 pid_t pid = provider->ftp_pid;
1726 proc_t *p;
1727
1728 /*
1729 * There need to be no associated enabled probes, no consumers
1730 * creating probes, and no meta providers referencing this provider.
1731 */
1732 ASSERT(provider->ftp_rcount == 0);
1733 ASSERT(provider->ftp_ccount == 0);
1734 ASSERT(provider->ftp_mcount == 0);
1735
1736 /*
1737 * If this provider hasn't been retired, we need to explicitly drop the
1738 * count of active providers on the associated process structure.
1739 */
1740 if (!provider->ftp_retired) {
1741 atomic_dec_64(&provider->ftp_proc->ftpc_acount);
1742 ASSERT(provider->ftp_proc->ftpc_acount <
1743 provider->ftp_proc->ftpc_rcount);
1744 }
1745
1746 fasttrap_proc_release(provider->ftp_proc);
1747
1748#if !defined(sun)
1749 mutex_destroy(&provider->ftp_mtx);
1750 mutex_destroy(&provider->ftp_cmtx);
1751#endif
1752 kmem_free(provider, sizeof (fasttrap_provider_t));
1753
1754 /*
1755 * Decrement p_dtrace_probes on the process whose provider we're
1756 * freeing. We don't have to worry about clobbering somone else's
1757 * modifications to it because we have locked the bucket that
1758 * corresponds to this process's hash chain in the provider hash
1759 * table. Don't sweat it if we can't find the process.
1760 */
1761 if ((p = pfind(pid)) == NULL) {
1762 return;
1763 }
1764
1765 p->p_dtrace_probes--;
1766#if !defined(sun)
1767 PROC_UNLOCK(p);
1768#endif
1769}
1770
1771static void
1772fasttrap_provider_retire(pid_t pid, const char *name, int mprov)
1773{
1774 fasttrap_provider_t *fp;
1775 fasttrap_bucket_t *bucket;
1776 dtrace_provider_id_t provid;
1777
1778 ASSERT(strlen(name) < sizeof (fp->ftp_name));
1779
1780 bucket = &fasttrap_provs.fth_table[FASTTRAP_PROVS_INDEX(pid, name)];
1781 mutex_enter(&bucket->ftb_mtx);
1782
1783 for (fp = bucket->ftb_data; fp != NULL; fp = fp->ftp_next) {
1784 if (fp->ftp_pid == pid && strcmp(fp->ftp_name, name) == 0 &&
1785 !fp->ftp_retired)
1786 break;
1787 }
1788
1789 if (fp == NULL) {
1790 mutex_exit(&bucket->ftb_mtx);
1791 return;
1792 }
1793
1794 mutex_enter(&fp->ftp_mtx);
1795 ASSERT(!mprov || fp->ftp_mcount > 0);
1796 if (mprov && --fp->ftp_mcount != 0) {
1797 mutex_exit(&fp->ftp_mtx);
1798 mutex_exit(&bucket->ftb_mtx);
1799 return;
1800 }
1801
1802 /*
1803 * Mark the provider to be removed in our post-processing step, mark it
1804 * retired, and drop the active count on its proc. Marking it indicates
1805 * that we should try to remove it; setting the retired flag indicates
1806 * that we're done with this provider; dropping the active the proc
1807 * releases our hold, and when this reaches zero (as it will during
1808 * exit or exec) the proc and associated providers become defunct.
1809 *
1810 * We obviously need to take the bucket lock before the provider lock
1811 * to perform the lookup, but we need to drop the provider lock
1812 * before calling into the DTrace framework since we acquire the
1813 * provider lock in callbacks invoked from the DTrace framework. The
1814 * bucket lock therefore protects the integrity of the provider hash
1815 * table.
1816 */
1817 atomic_dec_64(&fp->ftp_proc->ftpc_acount);
1818 ASSERT(fp->ftp_proc->ftpc_acount < fp->ftp_proc->ftpc_rcount);
1819
1820 fp->ftp_retired = 1;
1821 fp->ftp_marked = 1;
1822 provid = fp->ftp_provid;
1823 mutex_exit(&fp->ftp_mtx);
1824
1825 /*
1826 * We don't have to worry about invalidating the same provider twice
1827 * since fasttrap_provider_lookup() will ignore provider that have
1828 * been marked as retired.
1829 */
1830 dtrace_invalidate(provid);
1831
1832 mutex_exit(&bucket->ftb_mtx);
1833
1834 fasttrap_pid_cleanup();
1835}
1836
1837static int
1838fasttrap_uint32_cmp(const void *ap, const void *bp)
1839{
1840 return (*(const uint32_t *)ap - *(const uint32_t *)bp);
1841}
1842
1843static int
1844fasttrap_uint64_cmp(const void *ap, const void *bp)
1845{
1846 return (*(const uint64_t *)ap - *(const uint64_t *)bp);
1847}
1848
1849static int
1850fasttrap_add_probe(fasttrap_probe_spec_t *pdata)
1851{
1852 fasttrap_provider_t *provider;
1853 fasttrap_probe_t *pp;
1854 fasttrap_tracepoint_t *tp;
1855 char *name;
1856 int i, aframes = 0, whack;
1857
1858 /*
1859 * There needs to be at least one desired trace point.
1860 */
1861 if (pdata->ftps_noffs == 0)
1862 return (EINVAL);
1863
1864 switch (pdata->ftps_type) {
1865 case DTFTP_ENTRY:
1866 name = "entry";
1867 aframes = FASTTRAP_ENTRY_AFRAMES;
1868 break;
1869 case DTFTP_RETURN:
1870 name = "return";
1871 aframes = FASTTRAP_RETURN_AFRAMES;
1872 break;
1873 case DTFTP_OFFSETS:
1874 name = NULL;
1875 break;
1876 default:
1877 return (EINVAL);
1878 }
1879
1880 if ((provider = fasttrap_provider_lookup(pdata->ftps_pid,
1881 FASTTRAP_PID_NAME, &pid_attr)) == NULL)
1882 return (ESRCH);
1883
1884 /*
1885 * Increment this reference count to indicate that a consumer is
1886 * actively adding a new probe associated with this provider. This
1887 * prevents the provider from being deleted -- we'll need to check
1888 * for pending deletions when we drop this reference count.
1889 */
1890 provider->ftp_ccount++;
1891 mutex_exit(&provider->ftp_mtx);
1892
1893 /*
1894 * Grab the creation lock to ensure consistency between calls to
1895 * dtrace_probe_lookup() and dtrace_probe_create() in the face of
1896 * other threads creating probes. We must drop the provider lock
1897 * before taking this lock to avoid a three-way deadlock with the
1898 * DTrace framework.
1899 */
1900 mutex_enter(&provider->ftp_cmtx);
1901
1902 if (name == NULL) {
1903 for (i = 0; i < pdata->ftps_noffs; i++) {
1904 char name_str[17];
1905
1906 (void) sprintf(name_str, "%llx",
1907 (unsigned long long)pdata->ftps_offs[i]);
1908
1909 if (dtrace_probe_lookup(provider->ftp_provid,
1910 pdata->ftps_mod, pdata->ftps_func, name_str) != 0)
1911 continue;
1912
1913 atomic_inc_32(&fasttrap_total);
1914
1915 if (fasttrap_total > fasttrap_max) {
1916 atomic_dec_32(&fasttrap_total);
1917 goto no_mem;
1918 }
1919
1920 pp = kmem_zalloc(sizeof (fasttrap_probe_t), KM_SLEEP);
1921
1922 pp->ftp_prov = provider;
1923 pp->ftp_faddr = pdata->ftps_pc;
1924 pp->ftp_fsize = pdata->ftps_size;
1925 pp->ftp_pid = pdata->ftps_pid;
1926 pp->ftp_ntps = 1;
1927
1928 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t),
1929 KM_SLEEP);
1930
1931 tp->ftt_proc = provider->ftp_proc;
1932 tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc;
1933 tp->ftt_pid = pdata->ftps_pid;
1934
1935 pp->ftp_tps[0].fit_tp = tp;
1936 pp->ftp_tps[0].fit_id.fti_probe = pp;
1937 pp->ftp_tps[0].fit_id.fti_ptype = pdata->ftps_type;
1938
1939 pp->ftp_id = dtrace_probe_create(provider->ftp_provid,
1940 pdata->ftps_mod, pdata->ftps_func, name_str,
1941 FASTTRAP_OFFSET_AFRAMES, pp);
1942 }
1943
1944 } else if (dtrace_probe_lookup(provider->ftp_provid, pdata->ftps_mod,
1945 pdata->ftps_func, name) == 0) {
1946 atomic_add_32(&fasttrap_total, pdata->ftps_noffs);
1947
1948 if (fasttrap_total > fasttrap_max) {
1949 atomic_add_32(&fasttrap_total, -pdata->ftps_noffs);
1950 goto no_mem;
1951 }
1952
1953 /*
1954 * Make sure all tracepoint program counter values are unique.
1955 * We later assume that each probe has exactly one tracepoint
1956 * for a given pc.
1957 */
1958 qsort(pdata->ftps_offs, pdata->ftps_noffs,
1959 sizeof (uint64_t), fasttrap_uint64_cmp);
1960 for (i = 1; i < pdata->ftps_noffs; i++) {
1961 if (pdata->ftps_offs[i] > pdata->ftps_offs[i - 1])
1962 continue;
1963
1964 atomic_add_32(&fasttrap_total, -pdata->ftps_noffs);
1965 goto no_mem;
1966 }
1967
1968 ASSERT(pdata->ftps_noffs > 0);
1969 pp = kmem_zalloc(offsetof(fasttrap_probe_t,
1970 ftp_tps[pdata->ftps_noffs]), KM_SLEEP);
1971
1972 pp->ftp_prov = provider;
1973 pp->ftp_faddr = pdata->ftps_pc;
1974 pp->ftp_fsize = pdata->ftps_size;
1975 pp->ftp_pid = pdata->ftps_pid;
1976 pp->ftp_ntps = pdata->ftps_noffs;
1977
1978 for (i = 0; i < pdata->ftps_noffs; i++) {
1979 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t),
1980 KM_SLEEP);
1981
1982 tp->ftt_proc = provider->ftp_proc;
1983 tp->ftt_pc = pdata->ftps_offs[i] + pdata->ftps_pc;
1984 tp->ftt_pid = pdata->ftps_pid;
1985
1986 pp->ftp_tps[i].fit_tp = tp;
1987 pp->ftp_tps[i].fit_id.fti_probe = pp;
1988 pp->ftp_tps[i].fit_id.fti_ptype = pdata->ftps_type;
1989 }
1990
1991 pp->ftp_id = dtrace_probe_create(provider->ftp_provid,
1992 pdata->ftps_mod, pdata->ftps_func, name, aframes, pp);
1993 }
1994
1995 mutex_exit(&provider->ftp_cmtx);
1996
1997 /*
1998 * We know that the provider is still valid since we incremented the
1999 * creation reference count. If someone tried to clean up this provider
2000 * while we were using it (e.g. because the process called exec(2) or
2001 * exit(2)), take note of that and try to clean it up now.
2002 */
2003 mutex_enter(&provider->ftp_mtx);
2004 provider->ftp_ccount--;
2005 whack = provider->ftp_retired;
2006 mutex_exit(&provider->ftp_mtx);
2007
2008 if (whack)
2009 fasttrap_pid_cleanup();
2010
2011 return (0);
2012
2013no_mem:
2014 /*
2015 * If we've exhausted the allowable resources, we'll try to remove
2016 * this provider to free some up. This is to cover the case where
2017 * the user has accidentally created many more probes than was
2018 * intended (e.g. pid123:::).
2019 */
2020 mutex_exit(&provider->ftp_cmtx);
2021 mutex_enter(&provider->ftp_mtx);
2022 provider->ftp_ccount--;
2023 provider->ftp_marked = 1;
2024 mutex_exit(&provider->ftp_mtx);
2025
2026 fasttrap_pid_cleanup();
2027
2028 return (ENOMEM);
2029}
2030
2031/*ARGSUSED*/
2032static void *
2033fasttrap_meta_provide(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
2034{
2035 fasttrap_provider_t *provider;
2036
2037 /*
2038 * A 32-bit unsigned integer (like a pid for example) can be
2039 * expressed in 10 or fewer decimal digits. Make sure that we'll
2040 * have enough space for the provider name.
2041 */
2042 if (strlen(dhpv->dthpv_provname) + 10 >=
2043 sizeof (provider->ftp_name)) {
2044 printf("failed to instantiate provider %s: "
2045 "name too long to accomodate pid", dhpv->dthpv_provname);
2046 return (NULL);
2047 }
2048
2049 /*
2050 * Don't let folks spoof the true pid provider.
2051 */
2052 if (strcmp(dhpv->dthpv_provname, FASTTRAP_PID_NAME) == 0) {
2053 printf("failed to instantiate provider %s: "
2054 "%s is an invalid name", dhpv->dthpv_provname,
2055 FASTTRAP_PID_NAME);
2056 return (NULL);
2057 }
2058
2059 /*
2060 * The highest stability class that fasttrap supports is ISA; cap
2061 * the stability of the new provider accordingly.
2062 */
2063 if (dhpv->dthpv_pattr.dtpa_provider.dtat_class > DTRACE_CLASS_ISA)
2064 dhpv->dthpv_pattr.dtpa_provider.dtat_class = DTRACE_CLASS_ISA;
2065 if (dhpv->dthpv_pattr.dtpa_mod.dtat_class > DTRACE_CLASS_ISA)
2066 dhpv->dthpv_pattr.dtpa_mod.dtat_class = DTRACE_CLASS_ISA;
2067 if (dhpv->dthpv_pattr.dtpa_func.dtat_class > DTRACE_CLASS_ISA)
2068 dhpv->dthpv_pattr.dtpa_func.dtat_class = DTRACE_CLASS_ISA;
2069 if (dhpv->dthpv_pattr.dtpa_name.dtat_class > DTRACE_CLASS_ISA)
2070 dhpv->dthpv_pattr.dtpa_name.dtat_class = DTRACE_CLASS_ISA;
2071 if (dhpv->dthpv_pattr.dtpa_args.dtat_class > DTRACE_CLASS_ISA)
2072 dhpv->dthpv_pattr.dtpa_args.dtat_class = DTRACE_CLASS_ISA;
2073
2074 if ((provider = fasttrap_provider_lookup(pid, dhpv->dthpv_provname,
2075 &dhpv->dthpv_pattr)) == NULL) {
2076 printf("failed to instantiate provider %s for "
2077 "process %u", dhpv->dthpv_provname, (uint_t)pid);
2078 return (NULL);
2079 }
2080
2081 /*
2082 * Up the meta provider count so this provider isn't removed until
2083 * the meta provider has been told to remove it.
2084 */
2085 provider->ftp_mcount++;
2086
2087 mutex_exit(&provider->ftp_mtx);
2088
2089 return (provider);
2090}
2091
2092/*ARGSUSED*/
2093static void
2094fasttrap_meta_create_probe(void *arg, void *parg,
2095 dtrace_helper_probedesc_t *dhpb)
2096{
2097 fasttrap_provider_t *provider = parg;
2098 fasttrap_probe_t *pp;
2099 fasttrap_tracepoint_t *tp;
2100 int i, j;
2101 uint32_t ntps;
2102
2103 /*
2104 * Since the meta provider count is non-zero we don't have to worry
2105 * about this provider disappearing.
2106 */
2107 ASSERT(provider->ftp_mcount > 0);
2108
2109 /*
2110 * The offsets must be unique.
2111 */
2112 qsort(dhpb->dthpb_offs, dhpb->dthpb_noffs, sizeof (uint32_t),
2113 fasttrap_uint32_cmp);
2114 for (i = 1; i < dhpb->dthpb_noffs; i++) {
2115 if (dhpb->dthpb_base + dhpb->dthpb_offs[i] <=
2116 dhpb->dthpb_base + dhpb->dthpb_offs[i - 1])
2117 return;
2118 }
2119
2120 qsort(dhpb->dthpb_enoffs, dhpb->dthpb_nenoffs, sizeof (uint32_t),
2121 fasttrap_uint32_cmp);
2122 for (i = 1; i < dhpb->dthpb_nenoffs; i++) {
2123 if (dhpb->dthpb_base + dhpb->dthpb_enoffs[i] <=
2124 dhpb->dthpb_base + dhpb->dthpb_enoffs[i - 1])
2125 return;
2126 }
2127
2128 /*
2129 * Grab the creation lock to ensure consistency between calls to
2130 * dtrace_probe_lookup() and dtrace_probe_create() in the face of
2131 * other threads creating probes.
2132 */
2133 mutex_enter(&provider->ftp_cmtx);
2134
2135 if (dtrace_probe_lookup(provider->ftp_provid, dhpb->dthpb_mod,
2136 dhpb->dthpb_func, dhpb->dthpb_name) != 0) {
2137 mutex_exit(&provider->ftp_cmtx);
2138 return;
2139 }
2140
2141 ntps = dhpb->dthpb_noffs + dhpb->dthpb_nenoffs;
2142 ASSERT(ntps > 0);
2143
2144 atomic_add_32(&fasttrap_total, ntps);
2145
2146 if (fasttrap_total > fasttrap_max) {
2147 atomic_add_32(&fasttrap_total, -ntps);
2148 mutex_exit(&provider->ftp_cmtx);
2149 return;
2150 }
2151
2152 pp = kmem_zalloc(offsetof(fasttrap_probe_t, ftp_tps[ntps]), KM_SLEEP);
2153
2154 pp->ftp_prov = provider;
2155 pp->ftp_pid = provider->ftp_pid;
2156 pp->ftp_ntps = ntps;
2157 pp->ftp_nargs = dhpb->dthpb_xargc;
2158 pp->ftp_xtypes = dhpb->dthpb_xtypes;
2159 pp->ftp_ntypes = dhpb->dthpb_ntypes;
2160
2161 /*
2162 * First create a tracepoint for each actual point of interest.
2163 */
2164 for (i = 0; i < dhpb->dthpb_noffs; i++) {
2165 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP);
2166
2167 tp->ftt_proc = provider->ftp_proc;
2168 tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_offs[i];
2169 tp->ftt_pid = provider->ftp_pid;
2170
2171 pp->ftp_tps[i].fit_tp = tp;
2172 pp->ftp_tps[i].fit_id.fti_probe = pp;
2173#ifdef __sparc
2174 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_POST_OFFSETS;
2175#else
2176 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_OFFSETS;
2177#endif
2178 }
2179
2180 /*
2181 * Then create a tracepoint for each is-enabled point.
2182 */
2183 for (j = 0; i < ntps; i++, j++) {
2184 tp = kmem_zalloc(sizeof (fasttrap_tracepoint_t), KM_SLEEP);
2185
2186 tp->ftt_proc = provider->ftp_proc;
2187 tp->ftt_pc = dhpb->dthpb_base + dhpb->dthpb_enoffs[j];
2188 tp->ftt_pid = provider->ftp_pid;
2189
2190 pp->ftp_tps[i].fit_tp = tp;
2191 pp->ftp_tps[i].fit_id.fti_probe = pp;
2192 pp->ftp_tps[i].fit_id.fti_ptype = DTFTP_IS_ENABLED;
2193 }
2194
2195 /*
2196 * If the arguments are shuffled around we set the argument remapping
2197 * table. Later, when the probe fires, we only remap the arguments
2198 * if the table is non-NULL.
2199 */
2200 for (i = 0; i < dhpb->dthpb_xargc; i++) {
2201 if (dhpb->dthpb_args[i] != i) {
2202 pp->ftp_argmap = dhpb->dthpb_args;
2203 break;
2204 }
2205 }
2206
2207 /*
2208 * The probe is fully constructed -- register it with DTrace.
2209 */
2210 pp->ftp_id = dtrace_probe_create(provider->ftp_provid, dhpb->dthpb_mod,
2211 dhpb->dthpb_func, dhpb->dthpb_name, FASTTRAP_OFFSET_AFRAMES, pp);
2212
2213 mutex_exit(&provider->ftp_cmtx);
2214}
2215
2216/*ARGSUSED*/
2217static void
2218fasttrap_meta_remove(void *arg, dtrace_helper_provdesc_t *dhpv, pid_t pid)
2219{
2220 /*
2221 * Clean up the USDT provider. There may be active consumers of the
2222 * provider busy adding probes, no damage will actually befall the
2223 * provider until that count has dropped to zero. This just puts
2224 * the provider on death row.
2225 */
2226 fasttrap_provider_retire(pid, dhpv->dthpv_provname, 1);
2227}
2228
2229static dtrace_mops_t fasttrap_mops = {
2230 fasttrap_meta_create_probe,
2231 fasttrap_meta_provide,
2232 fasttrap_meta_remove
2233};
2234
2235/*ARGSUSED*/
2236static int
2237fasttrap_open(struct cdev *dev __unused, int oflags __unused,
2238 int devtype __unused, struct thread *td __unused)
2239{
2240 return (0);
2241}
2242
2243/*ARGSUSED*/
2244static int
2245fasttrap_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int fflag,
2246 struct thread *td)
2247{
2248#ifdef notyet
2249 struct kinfo_proc kp;
2250 const cred_t *cr = td->td_ucred;
2251#endif
2252 if (!dtrace_attached())
2253 return (EAGAIN);
2254
2255 if (cmd == FASTTRAPIOC_MAKEPROBE) {
2256 fasttrap_probe_spec_t *uprobe = *(fasttrap_probe_spec_t **)arg;
2257 fasttrap_probe_spec_t *probe;
2258 uint64_t noffs;
2259 size_t size;
2260 int ret, err;
2261
2262 if (copyin(&uprobe->ftps_noffs, &noffs,
2263 sizeof (uprobe->ftps_noffs)))
2264 return (EFAULT);
2265
2266 /*
2267 * Probes must have at least one tracepoint.
2268 */
2269 if (noffs == 0)
2270 return (EINVAL);
2271
2272 size = sizeof (fasttrap_probe_spec_t) +
2273 sizeof (probe->ftps_offs[0]) * (noffs - 1);
2274
2275 if (size > 1024 * 1024)
2276 return (ENOMEM);
2277
2278 probe = kmem_alloc(size, KM_SLEEP);
2279
2280 if (copyin(uprobe, probe, size) != 0 ||
2281 probe->ftps_noffs != noffs) {
2282 kmem_free(probe, size);
2283 return (EFAULT);
2284 }
2285
2286 /*
2287 * Verify that the function and module strings contain no
2288 * funny characters.
2289 */
2290 if (u8_validate(probe->ftps_func, strlen(probe->ftps_func),
2291 NULL, U8_VALIDATE_ENTIRE, &err) < 0) {
2292 ret = EINVAL;
2293 goto err;
2294 }
2295
2296 if (u8_validate(probe->ftps_mod, strlen(probe->ftps_mod),
2297 NULL, U8_VALIDATE_ENTIRE, &err) < 0) {
2298 ret = EINVAL;
2299 goto err;
2300 }
2301
2302#ifdef notyet
2303 if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {
2304 proc_t *p;
2305 pid_t pid = probe->ftps_pid;
2306
2307#if defined(sun)
2308 mutex_enter(&pidlock);
2309#endif
2310 /*
2311 * Report an error if the process doesn't exist
2312 * or is actively being birthed.
2313 */
2314 sx_slock(&proctree_lock);
2315 p = pfind(pid);
2316 if (p)
2317 fill_kinfo_proc(p, &kp);
2318 sx_sunlock(&proctree_lock);
2319 if (p == NULL || kp.ki_stat == SIDL) {
2320#if defined(sun)
2321 mutex_exit(&pidlock);
2322#endif
2323 return (ESRCH);
2324 }
2325#if defined(sun)
2326 mutex_enter(&p->p_lock);
2327 mutex_exit(&pidlock);
2328#else
2329 PROC_LOCK_ASSERT(p, MA_OWNED);
2330#endif
2331
2332#ifdef notyet
2333 if ((ret = priv_proc_cred_perm(cr, p, NULL,
2334 VREAD | VWRITE)) != 0) {
2335#if defined(sun)
2336 mutex_exit(&p->p_lock);
2337#else
2338 PROC_UNLOCK(p);
2339#endif
2340 return (ret);
2341 }
2342#endif /* notyet */
2343#if defined(sun)
2344 mutex_exit(&p->p_lock);
2345#else
2346 PROC_UNLOCK(p);
2347#endif
2348 }
2349#endif /* notyet */
2350
2351 ret = fasttrap_add_probe(probe);
2352err:
2353 kmem_free(probe, size);
2354
2355 return (ret);
2356
2357 } else if (cmd == FASTTRAPIOC_GETINSTR) {
2358 fasttrap_instr_query_t instr;
2359 fasttrap_tracepoint_t *tp;
2360 uint_t index;
2361#if defined(sun)
2362 int ret;
2363#endif
2364
2365#if defined(sun)
2366 if (copyin((void *)arg, &instr, sizeof (instr)) != 0)
2367 return (EFAULT);
2368#endif
2369
2370#ifdef notyet
2371 if (!PRIV_POLICY_CHOICE(cr, PRIV_ALL, B_FALSE)) {
2372 proc_t *p;
2373 pid_t pid = instr.ftiq_pid;
2374
2375#if defined(sun)
2376 mutex_enter(&pidlock);
2377#endif
2378 /*
2379 * Report an error if the process doesn't exist
2380 * or is actively being birthed.
2381 */
2382 sx_slock(&proctree_lock);
2383 p = pfind(pid);
2384 if (p)
2385 fill_kinfo_proc(p, &kp);
2386 sx_sunlock(&proctree_lock);
2387 if (p == NULL || kp.ki_stat == SIDL) {
2388#if defined(sun)
2389 mutex_exit(&pidlock);
2390#endif
2391 return (ESRCH);
2392 }
2393#if defined(sun)
2394 mutex_enter(&p->p_lock);
2395 mutex_exit(&pidlock);
2396#else
2397 PROC_LOCK_ASSERT(p, MA_OWNED);
2398#endif
2399
2400#ifdef notyet
2401 if ((ret = priv_proc_cred_perm(cr, p, NULL,
2402 VREAD)) != 0) {
2403#if defined(sun)
2404 mutex_exit(&p->p_lock);
2405#else
2406 PROC_UNLOCK(p);
2407#endif
2408 return (ret);
2409 }
2410#endif /* notyet */
2411
2412#if defined(sun)
2413 mutex_exit(&p->p_lock);
2414#else
2415 PROC_UNLOCK(p);
2416#endif
2417 }
2418#endif /* notyet */
2419
2420 index = FASTTRAP_TPOINTS_INDEX(instr.ftiq_pid, instr.ftiq_pc);
2421
2422 mutex_enter(&fasttrap_tpoints.fth_table[index].ftb_mtx);
2423 tp = fasttrap_tpoints.fth_table[index].ftb_data;
2424 while (tp != NULL) {
2425 if (instr.ftiq_pid == tp->ftt_pid &&
2426 instr.ftiq_pc == tp->ftt_pc &&
2427 tp->ftt_proc->ftpc_acount != 0)
2428 break;
2429
2430 tp = tp->ftt_next;
2431 }
2432
2433 if (tp == NULL) {
2434 mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx);
2435 return (ENOENT);
2436 }
2437
2438 bcopy(&tp->ftt_instr, &instr.ftiq_instr,
2439 sizeof (instr.ftiq_instr));
2440 mutex_exit(&fasttrap_tpoints.fth_table[index].ftb_mtx);
2441
2442 if (copyout(&instr, (void *)arg, sizeof (instr)) != 0)
2443 return (EFAULT);
2444
2445 return (0);
2446 }
2447
2448 return (EINVAL);
2449}
2450
2451static int
2452fasttrap_load(void)
2453{
2454 ulong_t nent;
2455 int i, ret;
2456
2457 /* Create the /dev/dtrace/fasttrap entry. */
2458 fasttrap_cdev = make_dev(&fasttrap_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
2459 "dtrace/fasttrap");
2460
2461 mtx_init(&fasttrap_cleanup_mtx, "fasttrap clean", "dtrace", MTX_DEF);
2462 mutex_init(&fasttrap_count_mtx, "fasttrap count mtx", MUTEX_DEFAULT,
2463 NULL);
2464
2465#if defined(sun)
2466 fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
2467 "fasttrap-max-probes", FASTTRAP_MAX_DEFAULT);
2468#else
2469 fasttrap_max = FASTTRAP_MAX_DEFAULT;
2470#endif
2471 fasttrap_total = 0;
2472
2473 /*
2474 * Conjure up the tracepoints hashtable...
2475 */
2476#if defined(sun)
2477 nent = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
2478 "fasttrap-hash-size", FASTTRAP_TPOINTS_DEFAULT_SIZE);
2479#else
2480 nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
2481#endif
2482
2483 if (nent == 0 || nent > 0x1000000)
2484 nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
2485
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