Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_ktrace.c
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1 /*- 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. 4 * Copyright (c) 2005 Robert N. M. Watson 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 4. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93 32 */ 33 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD: releng/11.0/sys/kern/kern_ktrace.c 298310 2016-04-19 23:48:27Z pfg $"); 36 37 #include "opt_ktrace.h" 38 39 #include <sys/param.h> 40 #include <sys/capsicum.h> 41 #include <sys/systm.h> 42 #include <sys/fcntl.h> 43 #include <sys/kernel.h> 44 #include <sys/kthread.h> 45 #include <sys/lock.h> 46 #include <sys/mutex.h> 47 #include <sys/malloc.h> 48 #include <sys/mount.h> 49 #include <sys/namei.h> 50 #include <sys/priv.h> 51 #include <sys/proc.h> 52 #include <sys/unistd.h> 53 #include <sys/vnode.h> 54 #include <sys/socket.h> 55 #include <sys/stat.h> 56 #include <sys/ktrace.h> 57 #include <sys/sx.h> 58 #include <sys/sysctl.h> 59 #include <sys/sysent.h> 60 #include <sys/syslog.h> 61 #include <sys/sysproto.h> 62 63 #include <security/mac/mac_framework.h> 64 65 /* 66 * The ktrace facility allows the tracing of certain key events in user space 67 * processes, such as system calls, signal delivery, context switches, and 68 * user generated events using utrace(2). It works by streaming event 69 * records and data to a vnode associated with the process using the 70 * ktrace(2) system call. In general, records can be written directly from 71 * the context that generates the event. One important exception to this is 72 * during a context switch, where sleeping is not permitted. To handle this 73 * case, trace events are generated using in-kernel ktr_request records, and 74 * then delivered to disk at a convenient moment -- either immediately, the 75 * next traceable event, at system call return, or at process exit. 76 * 77 * When dealing with multiple threads or processes writing to the same event 78 * log, ordering guarantees are weak: specifically, if an event has multiple 79 * records (i.e., system call enter and return), they may be interlaced with 80 * records from another event. Process and thread ID information is provided 81 * in the record, and user applications can de-interlace events if required. 82 */ 83 84 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 85 86 #ifdef KTRACE 87 88 FEATURE(ktrace, "Kernel support for system-call tracing"); 89 90 #ifndef KTRACE_REQUEST_POOL 91 #define KTRACE_REQUEST_POOL 100 92 #endif 93 94 struct ktr_request { 95 struct ktr_header ktr_header; 96 void *ktr_buffer; 97 union { 98 struct ktr_proc_ctor ktr_proc_ctor; 99 struct ktr_cap_fail ktr_cap_fail; 100 struct ktr_syscall ktr_syscall; 101 struct ktr_sysret ktr_sysret; 102 struct ktr_genio ktr_genio; 103 struct ktr_psig ktr_psig; 104 struct ktr_csw ktr_csw; 105 struct ktr_fault ktr_fault; 106 struct ktr_faultend ktr_faultend; 107 } ktr_data; 108 STAILQ_ENTRY(ktr_request) ktr_list; 109 }; 110 111 static int data_lengths[] = { 112 [KTR_SYSCALL] = offsetof(struct ktr_syscall, ktr_args), 113 [KTR_SYSRET] = sizeof(struct ktr_sysret), 114 [KTR_NAMEI] = 0, 115 [KTR_GENIO] = sizeof(struct ktr_genio), 116 [KTR_PSIG] = sizeof(struct ktr_psig), 117 [KTR_CSW] = sizeof(struct ktr_csw), 118 [KTR_USER] = 0, 119 [KTR_STRUCT] = 0, 120 [KTR_SYSCTL] = 0, 121 [KTR_PROCCTOR] = sizeof(struct ktr_proc_ctor), 122 [KTR_PROCDTOR] = 0, 123 [KTR_CAPFAIL] = sizeof(struct ktr_cap_fail), 124 [KTR_FAULT] = sizeof(struct ktr_fault), 125 [KTR_FAULTEND] = sizeof(struct ktr_faultend), 126 }; 127 128 static STAILQ_HEAD(, ktr_request) ktr_free; 129 130 static SYSCTL_NODE(_kern, OID_AUTO, ktrace, CTLFLAG_RD, 0, "KTRACE options"); 131 132 static u_int ktr_requestpool = KTRACE_REQUEST_POOL; 133 TUNABLE_INT("kern.ktrace.request_pool", &ktr_requestpool); 134 135 static u_int ktr_geniosize = PAGE_SIZE; 136 SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RWTUN, &ktr_geniosize, 137 0, "Maximum size of genio event payload"); 138 139 static int print_message = 1; 140 static struct mtx ktrace_mtx; 141 static struct sx ktrace_sx; 142 143 static void ktrace_init(void *dummy); 144 static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS); 145 static u_int ktrace_resize_pool(u_int oldsize, u_int newsize); 146 static struct ktr_request *ktr_getrequest_entered(struct thread *td, int type); 147 static struct ktr_request *ktr_getrequest(int type); 148 static void ktr_submitrequest(struct thread *td, struct ktr_request *req); 149 static void ktr_freeproc(struct proc *p, struct ucred **uc, 150 struct vnode **vp); 151 static void ktr_freerequest(struct ktr_request *req); 152 static void ktr_freerequest_locked(struct ktr_request *req); 153 static void ktr_writerequest(struct thread *td, struct ktr_request *req); 154 static int ktrcanset(struct thread *,struct proc *); 155 static int ktrsetchildren(struct thread *,struct proc *,int,int,struct vnode *); 156 static int ktrops(struct thread *,struct proc *,int,int,struct vnode *); 157 static void ktrprocctor_entered(struct thread *, struct proc *); 158 159 /* 160 * ktrace itself generates events, such as context switches, which we do not 161 * wish to trace. Maintain a flag, TDP_INKTRACE, on each thread to determine 162 * whether or not it is in a region where tracing of events should be 163 * suppressed. 164 */ 165 static void 166 ktrace_enter(struct thread *td) 167 { 168 169 KASSERT(!(td->td_pflags & TDP_INKTRACE), ("ktrace_enter: flag set")); 170 td->td_pflags |= TDP_INKTRACE; 171 } 172 173 static void 174 ktrace_exit(struct thread *td) 175 { 176 177 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_exit: flag not set")); 178 td->td_pflags &= ~TDP_INKTRACE; 179 } 180 181 static void 182 ktrace_assert(struct thread *td) 183 { 184 185 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_assert: flag not set")); 186 } 187 188 static void 189 ktrace_init(void *dummy) 190 { 191 struct ktr_request *req; 192 int i; 193 194 mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET); 195 sx_init(&ktrace_sx, "ktrace_sx"); 196 STAILQ_INIT(&ktr_free); 197 for (i = 0; i < ktr_requestpool; i++) { 198 req = malloc(sizeof(struct ktr_request), M_KTRACE, M_WAITOK); 199 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list); 200 } 201 } 202 SYSINIT(ktrace_init, SI_SUB_KTRACE, SI_ORDER_ANY, ktrace_init, NULL); 203 204 static int 205 sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS) 206 { 207 struct thread *td; 208 u_int newsize, oldsize, wantsize; 209 int error; 210 211 /* Handle easy read-only case first to avoid warnings from GCC. */ 212 if (!req->newptr) { 213 oldsize = ktr_requestpool; 214 return (SYSCTL_OUT(req, &oldsize, sizeof(u_int))); 215 } 216 217 error = SYSCTL_IN(req, &wantsize, sizeof(u_int)); 218 if (error) 219 return (error); 220 td = curthread; 221 ktrace_enter(td); 222 oldsize = ktr_requestpool; 223 newsize = ktrace_resize_pool(oldsize, wantsize); 224 ktrace_exit(td); 225 error = SYSCTL_OUT(req, &oldsize, sizeof(u_int)); 226 if (error) 227 return (error); 228 if (wantsize > oldsize && newsize < wantsize) 229 return (ENOSPC); 230 return (0); 231 } 232 SYSCTL_PROC(_kern_ktrace, OID_AUTO, request_pool, CTLTYPE_UINT|CTLFLAG_RW, 233 &ktr_requestpool, 0, sysctl_kern_ktrace_request_pool, "IU", 234 "Pool buffer size for ktrace(1)"); 235 236 static u_int 237 ktrace_resize_pool(u_int oldsize, u_int newsize) 238 { 239 STAILQ_HEAD(, ktr_request) ktr_new; 240 struct ktr_request *req; 241 int bound; 242 243 print_message = 1; 244 bound = newsize - oldsize; 245 if (bound == 0) 246 return (ktr_requestpool); 247 if (bound < 0) { 248 mtx_lock(&ktrace_mtx); 249 /* Shrink pool down to newsize if possible. */ 250 while (bound++ < 0) { 251 req = STAILQ_FIRST(&ktr_free); 252 if (req == NULL) 253 break; 254 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list); 255 ktr_requestpool--; 256 free(req, M_KTRACE); 257 } 258 } else { 259 /* Grow pool up to newsize. */ 260 STAILQ_INIT(&ktr_new); 261 while (bound-- > 0) { 262 req = malloc(sizeof(struct ktr_request), M_KTRACE, 263 M_WAITOK); 264 STAILQ_INSERT_HEAD(&ktr_new, req, ktr_list); 265 } 266 mtx_lock(&ktrace_mtx); 267 STAILQ_CONCAT(&ktr_free, &ktr_new); 268 ktr_requestpool += (newsize - oldsize); 269 } 270 mtx_unlock(&ktrace_mtx); 271 return (ktr_requestpool); 272 } 273 274 /* ktr_getrequest() assumes that ktr_comm[] is the same size as td_name[]. */ 275 CTASSERT(sizeof(((struct ktr_header *)NULL)->ktr_comm) == 276 (sizeof((struct thread *)NULL)->td_name)); 277 278 static struct ktr_request * 279 ktr_getrequest_entered(struct thread *td, int type) 280 { 281 struct ktr_request *req; 282 struct proc *p = td->td_proc; 283 int pm; 284 285 mtx_lock(&ktrace_mtx); 286 if (!KTRCHECK(td, type)) { 287 mtx_unlock(&ktrace_mtx); 288 return (NULL); 289 } 290 req = STAILQ_FIRST(&ktr_free); 291 if (req != NULL) { 292 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list); 293 req->ktr_header.ktr_type = type; 294 if (p->p_traceflag & KTRFAC_DROP) { 295 req->ktr_header.ktr_type |= KTR_DROP; 296 p->p_traceflag &= ~KTRFAC_DROP; 297 } 298 mtx_unlock(&ktrace_mtx); 299 microtime(&req->ktr_header.ktr_time); 300 req->ktr_header.ktr_pid = p->p_pid; 301 req->ktr_header.ktr_tid = td->td_tid; 302 bcopy(td->td_name, req->ktr_header.ktr_comm, 303 sizeof(req->ktr_header.ktr_comm)); 304 req->ktr_buffer = NULL; 305 req->ktr_header.ktr_len = 0; 306 } else { 307 p->p_traceflag |= KTRFAC_DROP; 308 pm = print_message; 309 print_message = 0; 310 mtx_unlock(&ktrace_mtx); 311 if (pm) 312 printf("Out of ktrace request objects.\n"); 313 } 314 return (req); 315 } 316 317 static struct ktr_request * 318 ktr_getrequest(int type) 319 { 320 struct thread *td = curthread; 321 struct ktr_request *req; 322 323 ktrace_enter(td); 324 req = ktr_getrequest_entered(td, type); 325 if (req == NULL) 326 ktrace_exit(td); 327 328 return (req); 329 } 330 331 /* 332 * Some trace generation environments don't permit direct access to VFS, 333 * such as during a context switch where sleeping is not allowed. Under these 334 * circumstances, queue a request to the thread to be written asynchronously 335 * later. 336 */ 337 static void 338 ktr_enqueuerequest(struct thread *td, struct ktr_request *req) 339 { 340 341 mtx_lock(&ktrace_mtx); 342 STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list); 343 mtx_unlock(&ktrace_mtx); 344 } 345 346 /* 347 * Drain any pending ktrace records from the per-thread queue to disk. This 348 * is used both internally before committing other records, and also on 349 * system call return. We drain all the ones we can find at the time when 350 * drain is requested, but don't keep draining after that as those events 351 * may be approximately "after" the current event. 352 */ 353 static void 354 ktr_drain(struct thread *td) 355 { 356 struct ktr_request *queued_req; 357 STAILQ_HEAD(, ktr_request) local_queue; 358 359 ktrace_assert(td); 360 sx_assert(&ktrace_sx, SX_XLOCKED); 361 362 STAILQ_INIT(&local_queue); 363 364 if (!STAILQ_EMPTY(&td->td_proc->p_ktr)) { 365 mtx_lock(&ktrace_mtx); 366 STAILQ_CONCAT(&local_queue, &td->td_proc->p_ktr); 367 mtx_unlock(&ktrace_mtx); 368 369 while ((queued_req = STAILQ_FIRST(&local_queue))) { 370 STAILQ_REMOVE_HEAD(&local_queue, ktr_list); 371 ktr_writerequest(td, queued_req); 372 ktr_freerequest(queued_req); 373 } 374 } 375 } 376 377 /* 378 * Submit a trace record for immediate commit to disk -- to be used only 379 * where entering VFS is OK. First drain any pending records that may have 380 * been cached in the thread. 381 */ 382 static void 383 ktr_submitrequest(struct thread *td, struct ktr_request *req) 384 { 385 386 ktrace_assert(td); 387 388 sx_xlock(&ktrace_sx); 389 ktr_drain(td); 390 ktr_writerequest(td, req); 391 ktr_freerequest(req); 392 sx_xunlock(&ktrace_sx); 393 ktrace_exit(td); 394 } 395 396 static void 397 ktr_freerequest(struct ktr_request *req) 398 { 399 400 mtx_lock(&ktrace_mtx); 401 ktr_freerequest_locked(req); 402 mtx_unlock(&ktrace_mtx); 403 } 404 405 static void 406 ktr_freerequest_locked(struct ktr_request *req) 407 { 408 409 mtx_assert(&ktrace_mtx, MA_OWNED); 410 if (req->ktr_buffer != NULL) 411 free(req->ktr_buffer, M_KTRACE); 412 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list); 413 } 414 415 /* 416 * Disable tracing for a process and release all associated resources. 417 * The caller is responsible for releasing a reference on the returned 418 * vnode and credentials. 419 */ 420 static void 421 ktr_freeproc(struct proc *p, struct ucred **uc, struct vnode **vp) 422 { 423 struct ktr_request *req; 424 425 PROC_LOCK_ASSERT(p, MA_OWNED); 426 mtx_assert(&ktrace_mtx, MA_OWNED); 427 *uc = p->p_tracecred; 428 p->p_tracecred = NULL; 429 if (vp != NULL) 430 *vp = p->p_tracevp; 431 p->p_tracevp = NULL; 432 p->p_traceflag = 0; 433 while ((req = STAILQ_FIRST(&p->p_ktr)) != NULL) { 434 STAILQ_REMOVE_HEAD(&p->p_ktr, ktr_list); 435 ktr_freerequest_locked(req); 436 } 437 } 438 439 void 440 ktrsyscall(code, narg, args) 441 int code, narg; 442 register_t args[]; 443 { 444 struct ktr_request *req; 445 struct ktr_syscall *ktp; 446 size_t buflen; 447 char *buf = NULL; 448 449 buflen = sizeof(register_t) * narg; 450 if (buflen > 0) { 451 buf = malloc(buflen, M_KTRACE, M_WAITOK); 452 bcopy(args, buf, buflen); 453 } 454 req = ktr_getrequest(KTR_SYSCALL); 455 if (req == NULL) { 456 if (buf != NULL) 457 free(buf, M_KTRACE); 458 return; 459 } 460 ktp = &req->ktr_data.ktr_syscall; 461 ktp->ktr_code = code; 462 ktp->ktr_narg = narg; 463 if (buflen > 0) { 464 req->ktr_header.ktr_len = buflen; 465 req->ktr_buffer = buf; 466 } 467 ktr_submitrequest(curthread, req); 468 } 469 470 void 471 ktrsysret(code, error, retval) 472 int code, error; 473 register_t retval; 474 { 475 struct ktr_request *req; 476 struct ktr_sysret *ktp; 477 478 req = ktr_getrequest(KTR_SYSRET); 479 if (req == NULL) 480 return; 481 ktp = &req->ktr_data.ktr_sysret; 482 ktp->ktr_code = code; 483 ktp->ktr_error = error; 484 ktp->ktr_retval = ((error == 0) ? retval: 0); /* what about val2 ? */ 485 ktr_submitrequest(curthread, req); 486 } 487 488 /* 489 * When a setuid process execs, disable tracing. 490 * 491 * XXX: We toss any pending asynchronous records. 492 */ 493 void 494 ktrprocexec(struct proc *p, struct ucred **uc, struct vnode **vp) 495 { 496 497 PROC_LOCK_ASSERT(p, MA_OWNED); 498 mtx_lock(&ktrace_mtx); 499 ktr_freeproc(p, uc, vp); 500 mtx_unlock(&ktrace_mtx); 501 } 502 503 /* 504 * When a process exits, drain per-process asynchronous trace records 505 * and disable tracing. 506 */ 507 void 508 ktrprocexit(struct thread *td) 509 { 510 struct ktr_request *req; 511 struct proc *p; 512 struct ucred *cred; 513 struct vnode *vp; 514 515 p = td->td_proc; 516 if (p->p_traceflag == 0) 517 return; 518 519 ktrace_enter(td); 520 req = ktr_getrequest_entered(td, KTR_PROCDTOR); 521 if (req != NULL) 522 ktr_enqueuerequest(td, req); 523 sx_xlock(&ktrace_sx); 524 ktr_drain(td); 525 sx_xunlock(&ktrace_sx); 526 PROC_LOCK(p); 527 mtx_lock(&ktrace_mtx); 528 ktr_freeproc(p, &cred, &vp); 529 mtx_unlock(&ktrace_mtx); 530 PROC_UNLOCK(p); 531 if (vp != NULL) 532 vrele(vp); 533 if (cred != NULL) 534 crfree(cred); 535 ktrace_exit(td); 536 } 537 538 static void 539 ktrprocctor_entered(struct thread *td, struct proc *p) 540 { 541 struct ktr_proc_ctor *ktp; 542 struct ktr_request *req; 543 struct thread *td2; 544 545 ktrace_assert(td); 546 td2 = FIRST_THREAD_IN_PROC(p); 547 req = ktr_getrequest_entered(td2, KTR_PROCCTOR); 548 if (req == NULL) 549 return; 550 ktp = &req->ktr_data.ktr_proc_ctor; 551 ktp->sv_flags = p->p_sysent->sv_flags; 552 ktr_enqueuerequest(td2, req); 553 } 554 555 void 556 ktrprocctor(struct proc *p) 557 { 558 struct thread *td = curthread; 559 560 if ((p->p_traceflag & KTRFAC_MASK) == 0) 561 return; 562 563 ktrace_enter(td); 564 ktrprocctor_entered(td, p); 565 ktrace_exit(td); 566 } 567 568 /* 569 * When a process forks, enable tracing in the new process if needed. 570 */ 571 void 572 ktrprocfork(struct proc *p1, struct proc *p2) 573 { 574 575 PROC_LOCK(p1); 576 mtx_lock(&ktrace_mtx); 577 KASSERT(p2->p_tracevp == NULL, ("new process has a ktrace vnode")); 578 if (p1->p_traceflag & KTRFAC_INHERIT) { 579 p2->p_traceflag = p1->p_traceflag; 580 if ((p2->p_tracevp = p1->p_tracevp) != NULL) { 581 VREF(p2->p_tracevp); 582 KASSERT(p1->p_tracecred != NULL, 583 ("ktrace vnode with no cred")); 584 p2->p_tracecred = crhold(p1->p_tracecred); 585 } 586 } 587 mtx_unlock(&ktrace_mtx); 588 PROC_UNLOCK(p1); 589 590 ktrprocctor(p2); 591 } 592 593 /* 594 * When a thread returns, drain any asynchronous records generated by the 595 * system call. 596 */ 597 void 598 ktruserret(struct thread *td) 599 { 600 601 ktrace_enter(td); 602 sx_xlock(&ktrace_sx); 603 ktr_drain(td); 604 sx_xunlock(&ktrace_sx); 605 ktrace_exit(td); 606 } 607 608 void 609 ktrnamei(path) 610 char *path; 611 { 612 struct ktr_request *req; 613 int namelen; 614 char *buf = NULL; 615 616 namelen = strlen(path); 617 if (namelen > 0) { 618 buf = malloc(namelen, M_KTRACE, M_WAITOK); 619 bcopy(path, buf, namelen); 620 } 621 req = ktr_getrequest(KTR_NAMEI); 622 if (req == NULL) { 623 if (buf != NULL) 624 free(buf, M_KTRACE); 625 return; 626 } 627 if (namelen > 0) { 628 req->ktr_header.ktr_len = namelen; 629 req->ktr_buffer = buf; 630 } 631 ktr_submitrequest(curthread, req); 632 } 633 634 void 635 ktrsysctl(name, namelen) 636 int *name; 637 u_int namelen; 638 { 639 struct ktr_request *req; 640 u_int mib[CTL_MAXNAME + 2]; 641 char *mibname; 642 size_t mibnamelen; 643 int error; 644 645 /* Lookup name of mib. */ 646 KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long")); 647 mib[0] = 0; 648 mib[1] = 1; 649 bcopy(name, mib + 2, namelen * sizeof(*name)); 650 mibnamelen = 128; 651 mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK); 652 error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen, 653 NULL, 0, &mibnamelen, 0); 654 if (error) { 655 free(mibname, M_KTRACE); 656 return; 657 } 658 req = ktr_getrequest(KTR_SYSCTL); 659 if (req == NULL) { 660 free(mibname, M_KTRACE); 661 return; 662 } 663 req->ktr_header.ktr_len = mibnamelen; 664 req->ktr_buffer = mibname; 665 ktr_submitrequest(curthread, req); 666 } 667 668 void 669 ktrgenio(fd, rw, uio, error) 670 int fd; 671 enum uio_rw rw; 672 struct uio *uio; 673 int error; 674 { 675 struct ktr_request *req; 676 struct ktr_genio *ktg; 677 int datalen; 678 char *buf; 679 680 if (error) { 681 free(uio, M_IOV); 682 return; 683 } 684 uio->uio_offset = 0; 685 uio->uio_rw = UIO_WRITE; 686 datalen = MIN(uio->uio_resid, ktr_geniosize); 687 buf = malloc(datalen, M_KTRACE, M_WAITOK); 688 error = uiomove(buf, datalen, uio); 689 free(uio, M_IOV); 690 if (error) { 691 free(buf, M_KTRACE); 692 return; 693 } 694 req = ktr_getrequest(KTR_GENIO); 695 if (req == NULL) { 696 free(buf, M_KTRACE); 697 return; 698 } 699 ktg = &req->ktr_data.ktr_genio; 700 ktg->ktr_fd = fd; 701 ktg->ktr_rw = rw; 702 req->ktr_header.ktr_len = datalen; 703 req->ktr_buffer = buf; 704 ktr_submitrequest(curthread, req); 705 } 706 707 void 708 ktrpsig(sig, action, mask, code) 709 int sig; 710 sig_t action; 711 sigset_t *mask; 712 int code; 713 { 714 struct thread *td = curthread; 715 struct ktr_request *req; 716 struct ktr_psig *kp; 717 718 req = ktr_getrequest(KTR_PSIG); 719 if (req == NULL) 720 return; 721 kp = &req->ktr_data.ktr_psig; 722 kp->signo = (char)sig; 723 kp->action = action; 724 kp->mask = *mask; 725 kp->code = code; 726 ktr_enqueuerequest(td, req); 727 ktrace_exit(td); 728 } 729 730 void 731 ktrcsw(out, user, wmesg) 732 int out, user; 733 const char *wmesg; 734 { 735 struct thread *td = curthread; 736 struct ktr_request *req; 737 struct ktr_csw *kc; 738 739 req = ktr_getrequest(KTR_CSW); 740 if (req == NULL) 741 return; 742 kc = &req->ktr_data.ktr_csw; 743 kc->out = out; 744 kc->user = user; 745 if (wmesg != NULL) 746 strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg)); 747 else 748 bzero(kc->wmesg, sizeof(kc->wmesg)); 749 ktr_enqueuerequest(td, req); 750 ktrace_exit(td); 751 } 752 753 void 754 ktrstruct(name, data, datalen) 755 const char *name; 756 void *data; 757 size_t datalen; 758 { 759 struct ktr_request *req; 760 char *buf; 761 size_t buflen, namelen; 762 763 if (data == NULL) 764 datalen = 0; 765 namelen = strlen(name) + 1; 766 buflen = namelen + datalen; 767 buf = malloc(buflen, M_KTRACE, M_WAITOK); 768 strcpy(buf, name); 769 bcopy(data, buf + namelen, datalen); 770 if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) { 771 free(buf, M_KTRACE); 772 return; 773 } 774 req->ktr_buffer = buf; 775 req->ktr_header.ktr_len = buflen; 776 ktr_submitrequest(curthread, req); 777 } 778 779 void 780 ktrcapfail(type, needed, held) 781 enum ktr_cap_fail_type type; 782 const cap_rights_t *needed; 783 const cap_rights_t *held; 784 { 785 struct thread *td = curthread; 786 struct ktr_request *req; 787 struct ktr_cap_fail *kcf; 788 789 req = ktr_getrequest(KTR_CAPFAIL); 790 if (req == NULL) 791 return; 792 kcf = &req->ktr_data.ktr_cap_fail; 793 kcf->cap_type = type; 794 if (needed != NULL) 795 kcf->cap_needed = *needed; 796 else 797 cap_rights_init(&kcf->cap_needed); 798 if (held != NULL) 799 kcf->cap_held = *held; 800 else 801 cap_rights_init(&kcf->cap_held); 802 ktr_enqueuerequest(td, req); 803 ktrace_exit(td); 804 } 805 806 void 807 ktrfault(vaddr, type) 808 vm_offset_t vaddr; 809 int type; 810 { 811 struct thread *td = curthread; 812 struct ktr_request *req; 813 struct ktr_fault *kf; 814 815 req = ktr_getrequest(KTR_FAULT); 816 if (req == NULL) 817 return; 818 kf = &req->ktr_data.ktr_fault; 819 kf->vaddr = vaddr; 820 kf->type = type; 821 ktr_enqueuerequest(td, req); 822 ktrace_exit(td); 823 } 824 825 void 826 ktrfaultend(result) 827 int result; 828 { 829 struct thread *td = curthread; 830 struct ktr_request *req; 831 struct ktr_faultend *kf; 832 833 req = ktr_getrequest(KTR_FAULTEND); 834 if (req == NULL) 835 return; 836 kf = &req->ktr_data.ktr_faultend; 837 kf->result = result; 838 ktr_enqueuerequest(td, req); 839 ktrace_exit(td); 840 } 841 #endif /* KTRACE */ 842 843 /* Interface and common routines */ 844 845 #ifndef _SYS_SYSPROTO_H_ 846 struct ktrace_args { 847 char *fname; 848 int ops; 849 int facs; 850 int pid; 851 }; 852 #endif 853 /* ARGSUSED */ 854 int 855 sys_ktrace(td, uap) 856 struct thread *td; 857 register struct ktrace_args *uap; 858 { 859 #ifdef KTRACE 860 register struct vnode *vp = NULL; 861 register struct proc *p; 862 struct pgrp *pg; 863 int facs = uap->facs & ~KTRFAC_ROOT; 864 int ops = KTROP(uap->ops); 865 int descend = uap->ops & KTRFLAG_DESCEND; 866 int nfound, ret = 0; 867 int flags, error = 0; 868 struct nameidata nd; 869 struct ucred *cred; 870 871 /* 872 * Need something to (un)trace. 873 */ 874 if (ops != KTROP_CLEARFILE && facs == 0) 875 return (EINVAL); 876 877 ktrace_enter(td); 878 if (ops != KTROP_CLEAR) { 879 /* 880 * an operation which requires a file argument. 881 */ 882 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td); 883 flags = FREAD | FWRITE | O_NOFOLLOW; 884 error = vn_open(&nd, &flags, 0, NULL); 885 if (error) { 886 ktrace_exit(td); 887 return (error); 888 } 889 NDFREE(&nd, NDF_ONLY_PNBUF); 890 vp = nd.ni_vp; 891 VOP_UNLOCK(vp, 0); 892 if (vp->v_type != VREG) { 893 (void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td); 894 ktrace_exit(td); 895 return (EACCES); 896 } 897 } 898 /* 899 * Clear all uses of the tracefile. 900 */ 901 if (ops == KTROP_CLEARFILE) { 902 int vrele_count; 903 904 vrele_count = 0; 905 sx_slock(&allproc_lock); 906 FOREACH_PROC_IN_SYSTEM(p) { 907 PROC_LOCK(p); 908 if (p->p_tracevp == vp) { 909 if (ktrcanset(td, p)) { 910 mtx_lock(&ktrace_mtx); 911 ktr_freeproc(p, &cred, NULL); 912 mtx_unlock(&ktrace_mtx); 913 vrele_count++; 914 crfree(cred); 915 } else 916 error = EPERM; 917 } 918 PROC_UNLOCK(p); 919 } 920 sx_sunlock(&allproc_lock); 921 if (vrele_count > 0) { 922 while (vrele_count-- > 0) 923 vrele(vp); 924 } 925 goto done; 926 } 927 /* 928 * do it 929 */ 930 sx_slock(&proctree_lock); 931 if (uap->pid < 0) { 932 /* 933 * by process group 934 */ 935 pg = pgfind(-uap->pid); 936 if (pg == NULL) { 937 sx_sunlock(&proctree_lock); 938 error = ESRCH; 939 goto done; 940 } 941 /* 942 * ktrops() may call vrele(). Lock pg_members 943 * by the proctree_lock rather than pg_mtx. 944 */ 945 PGRP_UNLOCK(pg); 946 nfound = 0; 947 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 948 PROC_LOCK(p); 949 if (p->p_state == PRS_NEW || 950 p_cansee(td, p) != 0) { 951 PROC_UNLOCK(p); 952 continue; 953 } 954 nfound++; 955 if (descend) 956 ret |= ktrsetchildren(td, p, ops, facs, vp); 957 else 958 ret |= ktrops(td, p, ops, facs, vp); 959 } 960 if (nfound == 0) { 961 sx_sunlock(&proctree_lock); 962 error = ESRCH; 963 goto done; 964 } 965 } else { 966 /* 967 * by pid 968 */ 969 p = pfind(uap->pid); 970 if (p == NULL) 971 error = ESRCH; 972 else 973 error = p_cansee(td, p); 974 if (error) { 975 if (p != NULL) 976 PROC_UNLOCK(p); 977 sx_sunlock(&proctree_lock); 978 goto done; 979 } 980 if (descend) 981 ret |= ktrsetchildren(td, p, ops, facs, vp); 982 else 983 ret |= ktrops(td, p, ops, facs, vp); 984 } 985 sx_sunlock(&proctree_lock); 986 if (!ret) 987 error = EPERM; 988 done: 989 if (vp != NULL) 990 (void) vn_close(vp, FWRITE, td->td_ucred, td); 991 ktrace_exit(td); 992 return (error); 993 #else /* !KTRACE */ 994 return (ENOSYS); 995 #endif /* KTRACE */ 996 } 997 998 /* ARGSUSED */ 999 int 1000 sys_utrace(td, uap) 1001 struct thread *td; 1002 register struct utrace_args *uap; 1003 { 1004 1005 #ifdef KTRACE 1006 struct ktr_request *req; 1007 void *cp; 1008 int error; 1009 1010 if (!KTRPOINT(td, KTR_USER)) 1011 return (0); 1012 if (uap->len > KTR_USER_MAXLEN) 1013 return (EINVAL); 1014 cp = malloc(uap->len, M_KTRACE, M_WAITOK); 1015 error = copyin(uap->addr, cp, uap->len); 1016 if (error) { 1017 free(cp, M_KTRACE); 1018 return (error); 1019 } 1020 req = ktr_getrequest(KTR_USER); 1021 if (req == NULL) { 1022 free(cp, M_KTRACE); 1023 return (ENOMEM); 1024 } 1025 req->ktr_buffer = cp; 1026 req->ktr_header.ktr_len = uap->len; 1027 ktr_submitrequest(td, req); 1028 return (0); 1029 #else /* !KTRACE */ 1030 return (ENOSYS); 1031 #endif /* KTRACE */ 1032 } 1033 1034 #ifdef KTRACE 1035 static int 1036 ktrops(td, p, ops, facs, vp) 1037 struct thread *td; 1038 struct proc *p; 1039 int ops, facs; 1040 struct vnode *vp; 1041 { 1042 struct vnode *tracevp = NULL; 1043 struct ucred *tracecred = NULL; 1044 1045 PROC_LOCK_ASSERT(p, MA_OWNED); 1046 if (!ktrcanset(td, p)) { 1047 PROC_UNLOCK(p); 1048 return (0); 1049 } 1050 if (p->p_flag & P_WEXIT) { 1051 /* If the process is exiting, just ignore it. */ 1052 PROC_UNLOCK(p); 1053 return (1); 1054 } 1055 mtx_lock(&ktrace_mtx); 1056 if (ops == KTROP_SET) { 1057 if (p->p_tracevp != vp) { 1058 /* 1059 * if trace file already in use, relinquish below 1060 */ 1061 tracevp = p->p_tracevp; 1062 VREF(vp); 1063 p->p_tracevp = vp; 1064 } 1065 if (p->p_tracecred != td->td_ucred) { 1066 tracecred = p->p_tracecred; 1067 p->p_tracecred = crhold(td->td_ucred); 1068 } 1069 p->p_traceflag |= facs; 1070 if (priv_check(td, PRIV_KTRACE) == 0) 1071 p->p_traceflag |= KTRFAC_ROOT; 1072 } else { 1073 /* KTROP_CLEAR */ 1074 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) 1075 /* no more tracing */ 1076 ktr_freeproc(p, &tracecred, &tracevp); 1077 } 1078 mtx_unlock(&ktrace_mtx); 1079 if ((p->p_traceflag & KTRFAC_MASK) != 0) 1080 ktrprocctor_entered(td, p); 1081 PROC_UNLOCK(p); 1082 if (tracevp != NULL) 1083 vrele(tracevp); 1084 if (tracecred != NULL) 1085 crfree(tracecred); 1086 1087 return (1); 1088 } 1089 1090 static int 1091 ktrsetchildren(td, top, ops, facs, vp) 1092 struct thread *td; 1093 struct proc *top; 1094 int ops, facs; 1095 struct vnode *vp; 1096 { 1097 register struct proc *p; 1098 register int ret = 0; 1099 1100 p = top; 1101 PROC_LOCK_ASSERT(p, MA_OWNED); 1102 sx_assert(&proctree_lock, SX_LOCKED); 1103 for (;;) { 1104 ret |= ktrops(td, p, ops, facs, vp); 1105 /* 1106 * If this process has children, descend to them next, 1107 * otherwise do any siblings, and if done with this level, 1108 * follow back up the tree (but not past top). 1109 */ 1110 if (!LIST_EMPTY(&p->p_children)) 1111 p = LIST_FIRST(&p->p_children); 1112 else for (;;) { 1113 if (p == top) 1114 return (ret); 1115 if (LIST_NEXT(p, p_sibling)) { 1116 p = LIST_NEXT(p, p_sibling); 1117 break; 1118 } 1119 p = p->p_pptr; 1120 } 1121 PROC_LOCK(p); 1122 } 1123 /*NOTREACHED*/ 1124 } 1125 1126 static void 1127 ktr_writerequest(struct thread *td, struct ktr_request *req) 1128 { 1129 struct ktr_header *kth; 1130 struct vnode *vp; 1131 struct proc *p; 1132 struct ucred *cred; 1133 struct uio auio; 1134 struct iovec aiov[3]; 1135 struct mount *mp; 1136 int datalen, buflen, vrele_count; 1137 int error; 1138 1139 /* 1140 * We hold the vnode and credential for use in I/O in case ktrace is 1141 * disabled on the process as we write out the request. 1142 * 1143 * XXXRW: This is not ideal: we could end up performing a write after 1144 * the vnode has been closed. 1145 */ 1146 mtx_lock(&ktrace_mtx); 1147 vp = td->td_proc->p_tracevp; 1148 cred = td->td_proc->p_tracecred; 1149 1150 /* 1151 * If vp is NULL, the vp has been cleared out from under this 1152 * request, so just drop it. Make sure the credential and vnode are 1153 * in sync: we should have both or neither. 1154 */ 1155 if (vp == NULL) { 1156 KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL")); 1157 mtx_unlock(&ktrace_mtx); 1158 return; 1159 } 1160 VREF(vp); 1161 KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL")); 1162 crhold(cred); 1163 mtx_unlock(&ktrace_mtx); 1164 1165 kth = &req->ktr_header; 1166 KASSERT(((u_short)kth->ktr_type & ~KTR_DROP) < nitems(data_lengths), 1167 ("data_lengths array overflow")); 1168 datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_DROP]; 1169 buflen = kth->ktr_len; 1170 auio.uio_iov = &aiov[0]; 1171 auio.uio_offset = 0; 1172 auio.uio_segflg = UIO_SYSSPACE; 1173 auio.uio_rw = UIO_WRITE; 1174 aiov[0].iov_base = (caddr_t)kth; 1175 aiov[0].iov_len = sizeof(struct ktr_header); 1176 auio.uio_resid = sizeof(struct ktr_header); 1177 auio.uio_iovcnt = 1; 1178 auio.uio_td = td; 1179 if (datalen != 0) { 1180 aiov[1].iov_base = (caddr_t)&req->ktr_data; 1181 aiov[1].iov_len = datalen; 1182 auio.uio_resid += datalen; 1183 auio.uio_iovcnt++; 1184 kth->ktr_len += datalen; 1185 } 1186 if (buflen != 0) { 1187 KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write")); 1188 aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer; 1189 aiov[auio.uio_iovcnt].iov_len = buflen; 1190 auio.uio_resid += buflen; 1191 auio.uio_iovcnt++; 1192 } 1193 1194 vn_start_write(vp, &mp, V_WAIT); 1195 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1196 #ifdef MAC 1197 error = mac_vnode_check_write(cred, NOCRED, vp); 1198 if (error == 0) 1199 #endif 1200 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred); 1201 VOP_UNLOCK(vp, 0); 1202 vn_finished_write(mp); 1203 crfree(cred); 1204 if (!error) { 1205 vrele(vp); 1206 return; 1207 } 1208 1209 /* 1210 * If error encountered, give up tracing on this vnode. We defer 1211 * all the vrele()'s on the vnode until after we are finished walking 1212 * the various lists to avoid needlessly holding locks. 1213 * NB: at this point we still hold the vnode reference that must 1214 * not go away as we need the valid vnode to compare with. Thus let 1215 * vrele_count start at 1 and the reference will be freed 1216 * by the loop at the end after our last use of vp. 1217 */ 1218 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 1219 error); 1220 vrele_count = 1; 1221 /* 1222 * First, clear this vnode from being used by any processes in the 1223 * system. 1224 * XXX - If one process gets an EPERM writing to the vnode, should 1225 * we really do this? Other processes might have suitable 1226 * credentials for the operation. 1227 */ 1228 cred = NULL; 1229 sx_slock(&allproc_lock); 1230 FOREACH_PROC_IN_SYSTEM(p) { 1231 PROC_LOCK(p); 1232 if (p->p_tracevp == vp) { 1233 mtx_lock(&ktrace_mtx); 1234 ktr_freeproc(p, &cred, NULL); 1235 mtx_unlock(&ktrace_mtx); 1236 vrele_count++; 1237 } 1238 PROC_UNLOCK(p); 1239 if (cred != NULL) { 1240 crfree(cred); 1241 cred = NULL; 1242 } 1243 } 1244 sx_sunlock(&allproc_lock); 1245 1246 while (vrele_count-- > 0) 1247 vrele(vp); 1248 } 1249 1250 /* 1251 * Return true if caller has permission to set the ktracing state 1252 * of target. Essentially, the target can't possess any 1253 * more permissions than the caller. KTRFAC_ROOT signifies that 1254 * root previously set the tracing status on the target process, and 1255 * so, only root may further change it. 1256 */ 1257 static int 1258 ktrcanset(td, targetp) 1259 struct thread *td; 1260 struct proc *targetp; 1261 { 1262 1263 PROC_LOCK_ASSERT(targetp, MA_OWNED); 1264 if (targetp->p_traceflag & KTRFAC_ROOT && 1265 priv_check(td, PRIV_KTRACE)) 1266 return (0); 1267 1268 if (p_candebug(td, targetp) != 0) 1269 return (0); 1270 1271 return (1); 1272 } 1273 1274 #endif /* KTRACE */
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