1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. 6 * Copyright (c) 2005 Robert N. M. Watson 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#)kern_ktrace.c 8.2 (Berkeley) 9/23/93 34 */ 35 36 #include <sys/cdefs.h> 37 __FBSDID("$FreeBSD$"); 38 39 #include "opt_ktrace.h" 40 41 #include <sys/param.h> 42 #include <sys/capsicum.h> 43 #include <sys/systm.h> 44 #include <sys/fcntl.h> 45 #include <sys/kernel.h> 46 #include <sys/kthread.h> 47 #include <sys/lock.h> 48 #include <sys/mutex.h> 49 #include <sys/malloc.h> 50 #include <sys/mount.h> 51 #include <sys/namei.h> 52 #include <sys/priv.h> 53 #include <sys/proc.h> 54 #include <sys/unistd.h> 55 #include <sys/vnode.h> 56 #include <sys/socket.h> 57 #include <sys/stat.h> 58 #include <sys/ktrace.h> 59 #include <sys/sx.h> 60 #include <sys/sysctl.h> 61 #include <sys/sysent.h> 62 #include <sys/syslog.h> 63 #include <sys/sysproto.h> 64 65 #include <security/mac/mac_framework.h> 66 67 /* 68 * The ktrace facility allows the tracing of certain key events in user space 69 * processes, such as system calls, signal delivery, context switches, and 70 * user generated events using utrace(2). It works by streaming event 71 * records and data to a vnode associated with the process using the 72 * ktrace(2) system call. In general, records can be written directly from 73 * the context that generates the event. One important exception to this is 74 * during a context switch, where sleeping is not permitted. To handle this 75 * case, trace events are generated using in-kernel ktr_request records, and 76 * then delivered to disk at a convenient moment -- either immediately, the 77 * next traceable event, at system call return, or at process exit. 78 * 79 * When dealing with multiple threads or processes writing to the same event 80 * log, ordering guarantees are weak: specifically, if an event has multiple 81 * records (i.e., system call enter and return), they may be interlaced with 82 * records from another event. Process and thread ID information is provided 83 * in the record, and user applications can de-interlace events if required. 84 */ 85 86 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 87 88 #ifdef KTRACE 89 90 FEATURE(ktrace, "Kernel support for system-call tracing"); 91 92 #ifndef KTRACE_REQUEST_POOL 93 #define KTRACE_REQUEST_POOL 100 94 #endif 95 96 struct ktr_request { 97 struct ktr_header ktr_header; 98 void *ktr_buffer; 99 union { 100 struct ktr_proc_ctor ktr_proc_ctor; 101 struct ktr_cap_fail ktr_cap_fail; 102 struct ktr_syscall ktr_syscall; 103 struct ktr_sysret ktr_sysret; 104 struct ktr_genio ktr_genio; 105 struct ktr_psig ktr_psig; 106 struct ktr_csw ktr_csw; 107 struct ktr_fault ktr_fault; 108 struct ktr_faultend ktr_faultend; 109 struct ktr_struct_array ktr_struct_array; 110 } ktr_data; 111 STAILQ_ENTRY(ktr_request) ktr_list; 112 }; 113 114 static int data_lengths[] = { 115 [KTR_SYSCALL] = offsetof(struct ktr_syscall, ktr_args), 116 [KTR_SYSRET] = sizeof(struct ktr_sysret), 117 [KTR_NAMEI] = 0, 118 [KTR_GENIO] = sizeof(struct ktr_genio), 119 [KTR_PSIG] = sizeof(struct ktr_psig), 120 [KTR_CSW] = sizeof(struct ktr_csw), 121 [KTR_USER] = 0, 122 [KTR_STRUCT] = 0, 123 [KTR_SYSCTL] = 0, 124 [KTR_PROCCTOR] = sizeof(struct ktr_proc_ctor), 125 [KTR_PROCDTOR] = 0, 126 [KTR_CAPFAIL] = sizeof(struct ktr_cap_fail), 127 [KTR_FAULT] = sizeof(struct ktr_fault), 128 [KTR_FAULTEND] = sizeof(struct ktr_faultend), 129 [KTR_STRUCT_ARRAY] = sizeof(struct ktr_struct_array), 130 }; 131 132 static STAILQ_HEAD(, ktr_request) ktr_free; 133 134 static SYSCTL_NODE(_kern, OID_AUTO, ktrace, CTLFLAG_RD, 0, "KTRACE options"); 135 136 static u_int ktr_requestpool = KTRACE_REQUEST_POOL; 137 TUNABLE_INT("kern.ktrace.request_pool", &ktr_requestpool); 138 139 u_int ktr_geniosize = PAGE_SIZE; 140 SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RWTUN, &ktr_geniosize, 141 0, "Maximum size of genio event payload"); 142 143 static int print_message = 1; 144 static struct mtx ktrace_mtx; 145 static struct sx ktrace_sx; 146 147 static void ktrace_init(void *dummy); 148 static int sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS); 149 static u_int ktrace_resize_pool(u_int oldsize, u_int newsize); 150 static struct ktr_request *ktr_getrequest_entered(struct thread *td, int type); 151 static struct ktr_request *ktr_getrequest(int type); 152 static void ktr_submitrequest(struct thread *td, struct ktr_request *req); 153 static void ktr_freeproc(struct proc *p, struct ucred **uc, 154 struct vnode **vp); 155 static void ktr_freerequest(struct ktr_request *req); 156 static void ktr_freerequest_locked(struct ktr_request *req); 157 static void ktr_writerequest(struct thread *td, struct ktr_request *req); 158 static int ktrcanset(struct thread *,struct proc *); 159 static int ktrsetchildren(struct thread *,struct proc *,int,int,struct vnode *); 160 static int ktrops(struct thread *,struct proc *,int,int,struct vnode *); 161 static void ktrprocctor_entered(struct thread *, struct proc *); 162 163 /* 164 * ktrace itself generates events, such as context switches, which we do not 165 * wish to trace. Maintain a flag, TDP_INKTRACE, on each thread to determine 166 * whether or not it is in a region where tracing of events should be 167 * suppressed. 168 */ 169 static void 170 ktrace_enter(struct thread *td) 171 { 172 173 KASSERT(!(td->td_pflags & TDP_INKTRACE), ("ktrace_enter: flag set")); 174 td->td_pflags |= TDP_INKTRACE; 175 } 176 177 static void 178 ktrace_exit(struct thread *td) 179 { 180 181 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_exit: flag not set")); 182 td->td_pflags &= ~TDP_INKTRACE; 183 } 184 185 static void 186 ktrace_assert(struct thread *td) 187 { 188 189 KASSERT(td->td_pflags & TDP_INKTRACE, ("ktrace_assert: flag not set")); 190 } 191 192 static void 193 ktrace_init(void *dummy) 194 { 195 struct ktr_request *req; 196 int i; 197 198 mtx_init(&ktrace_mtx, "ktrace", NULL, MTX_DEF | MTX_QUIET); 199 sx_init(&ktrace_sx, "ktrace_sx"); 200 STAILQ_INIT(&ktr_free); 201 for (i = 0; i < ktr_requestpool; i++) { 202 req = malloc(sizeof(struct ktr_request), M_KTRACE, M_WAITOK); 203 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list); 204 } 205 } 206 SYSINIT(ktrace_init, SI_SUB_KTRACE, SI_ORDER_ANY, ktrace_init, NULL); 207 208 static int 209 sysctl_kern_ktrace_request_pool(SYSCTL_HANDLER_ARGS) 210 { 211 struct thread *td; 212 u_int newsize, oldsize, wantsize; 213 int error; 214 215 /* Handle easy read-only case first to avoid warnings from GCC. */ 216 if (!req->newptr) { 217 oldsize = ktr_requestpool; 218 return (SYSCTL_OUT(req, &oldsize, sizeof(u_int))); 219 } 220 221 error = SYSCTL_IN(req, &wantsize, sizeof(u_int)); 222 if (error) 223 return (error); 224 td = curthread; 225 ktrace_enter(td); 226 oldsize = ktr_requestpool; 227 newsize = ktrace_resize_pool(oldsize, wantsize); 228 ktrace_exit(td); 229 error = SYSCTL_OUT(req, &oldsize, sizeof(u_int)); 230 if (error) 231 return (error); 232 if (wantsize > oldsize && newsize < wantsize) 233 return (ENOSPC); 234 return (0); 235 } 236 SYSCTL_PROC(_kern_ktrace, OID_AUTO, request_pool, CTLTYPE_UINT|CTLFLAG_RW, 237 &ktr_requestpool, 0, sysctl_kern_ktrace_request_pool, "IU", 238 "Pool buffer size for ktrace(1)"); 239 240 static u_int 241 ktrace_resize_pool(u_int oldsize, u_int newsize) 242 { 243 STAILQ_HEAD(, ktr_request) ktr_new; 244 struct ktr_request *req; 245 int bound; 246 247 print_message = 1; 248 bound = newsize - oldsize; 249 if (bound == 0) 250 return (ktr_requestpool); 251 if (bound < 0) { 252 mtx_lock(&ktrace_mtx); 253 /* Shrink pool down to newsize if possible. */ 254 while (bound++ < 0) { 255 req = STAILQ_FIRST(&ktr_free); 256 if (req == NULL) 257 break; 258 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list); 259 ktr_requestpool--; 260 free(req, M_KTRACE); 261 } 262 } else { 263 /* Grow pool up to newsize. */ 264 STAILQ_INIT(&ktr_new); 265 while (bound-- > 0) { 266 req = malloc(sizeof(struct ktr_request), M_KTRACE, 267 M_WAITOK); 268 STAILQ_INSERT_HEAD(&ktr_new, req, ktr_list); 269 } 270 mtx_lock(&ktrace_mtx); 271 STAILQ_CONCAT(&ktr_free, &ktr_new); 272 ktr_requestpool += (newsize - oldsize); 273 } 274 mtx_unlock(&ktrace_mtx); 275 return (ktr_requestpool); 276 } 277 278 /* ktr_getrequest() assumes that ktr_comm[] is the same size as td_name[]. */ 279 CTASSERT(sizeof(((struct ktr_header *)NULL)->ktr_comm) == 280 (sizeof((struct thread *)NULL)->td_name)); 281 282 static struct ktr_request * 283 ktr_getrequest_entered(struct thread *td, int type) 284 { 285 struct ktr_request *req; 286 struct proc *p = td->td_proc; 287 int pm; 288 289 mtx_lock(&ktrace_mtx); 290 if (!KTRCHECK(td, type)) { 291 mtx_unlock(&ktrace_mtx); 292 return (NULL); 293 } 294 req = STAILQ_FIRST(&ktr_free); 295 if (req != NULL) { 296 STAILQ_REMOVE_HEAD(&ktr_free, ktr_list); 297 req->ktr_header.ktr_type = type; 298 if (p->p_traceflag & KTRFAC_DROP) { 299 req->ktr_header.ktr_type |= KTR_DROP; 300 p->p_traceflag &= ~KTRFAC_DROP; 301 } 302 mtx_unlock(&ktrace_mtx); 303 microtime(&req->ktr_header.ktr_time); 304 req->ktr_header.ktr_pid = p->p_pid; 305 req->ktr_header.ktr_tid = td->td_tid; 306 bcopy(td->td_name, req->ktr_header.ktr_comm, 307 sizeof(req->ktr_header.ktr_comm)); 308 req->ktr_buffer = NULL; 309 req->ktr_header.ktr_len = 0; 310 } else { 311 p->p_traceflag |= KTRFAC_DROP; 312 pm = print_message; 313 print_message = 0; 314 mtx_unlock(&ktrace_mtx); 315 if (pm) 316 printf("Out of ktrace request objects.\n"); 317 } 318 return (req); 319 } 320 321 static struct ktr_request * 322 ktr_getrequest(int type) 323 { 324 struct thread *td = curthread; 325 struct ktr_request *req; 326 327 ktrace_enter(td); 328 req = ktr_getrequest_entered(td, type); 329 if (req == NULL) 330 ktrace_exit(td); 331 332 return (req); 333 } 334 335 /* 336 * Some trace generation environments don't permit direct access to VFS, 337 * such as during a context switch where sleeping is not allowed. Under these 338 * circumstances, queue a request to the thread to be written asynchronously 339 * later. 340 */ 341 static void 342 ktr_enqueuerequest(struct thread *td, struct ktr_request *req) 343 { 344 345 mtx_lock(&ktrace_mtx); 346 STAILQ_INSERT_TAIL(&td->td_proc->p_ktr, req, ktr_list); 347 mtx_unlock(&ktrace_mtx); 348 } 349 350 /* 351 * Drain any pending ktrace records from the per-thread queue to disk. This 352 * is used both internally before committing other records, and also on 353 * system call return. We drain all the ones we can find at the time when 354 * drain is requested, but don't keep draining after that as those events 355 * may be approximately "after" the current event. 356 */ 357 static void 358 ktr_drain(struct thread *td) 359 { 360 struct ktr_request *queued_req; 361 STAILQ_HEAD(, ktr_request) local_queue; 362 363 ktrace_assert(td); 364 sx_assert(&ktrace_sx, SX_XLOCKED); 365 366 STAILQ_INIT(&local_queue); 367 368 if (!STAILQ_EMPTY(&td->td_proc->p_ktr)) { 369 mtx_lock(&ktrace_mtx); 370 STAILQ_CONCAT(&local_queue, &td->td_proc->p_ktr); 371 mtx_unlock(&ktrace_mtx); 372 373 while ((queued_req = STAILQ_FIRST(&local_queue))) { 374 STAILQ_REMOVE_HEAD(&local_queue, ktr_list); 375 ktr_writerequest(td, queued_req); 376 ktr_freerequest(queued_req); 377 } 378 } 379 } 380 381 /* 382 * Submit a trace record for immediate commit to disk -- to be used only 383 * where entering VFS is OK. First drain any pending records that may have 384 * been cached in the thread. 385 */ 386 static void 387 ktr_submitrequest(struct thread *td, struct ktr_request *req) 388 { 389 390 ktrace_assert(td); 391 392 sx_xlock(&ktrace_sx); 393 ktr_drain(td); 394 ktr_writerequest(td, req); 395 ktr_freerequest(req); 396 sx_xunlock(&ktrace_sx); 397 ktrace_exit(td); 398 } 399 400 static void 401 ktr_freerequest(struct ktr_request *req) 402 { 403 404 mtx_lock(&ktrace_mtx); 405 ktr_freerequest_locked(req); 406 mtx_unlock(&ktrace_mtx); 407 } 408 409 static void 410 ktr_freerequest_locked(struct ktr_request *req) 411 { 412 413 mtx_assert(&ktrace_mtx, MA_OWNED); 414 if (req->ktr_buffer != NULL) 415 free(req->ktr_buffer, M_KTRACE); 416 STAILQ_INSERT_HEAD(&ktr_free, req, ktr_list); 417 } 418 419 /* 420 * Disable tracing for a process and release all associated resources. 421 * The caller is responsible for releasing a reference on the returned 422 * vnode and credentials. 423 */ 424 static void 425 ktr_freeproc(struct proc *p, struct ucred **uc, struct vnode **vp) 426 { 427 struct ktr_request *req; 428 429 PROC_LOCK_ASSERT(p, MA_OWNED); 430 mtx_assert(&ktrace_mtx, MA_OWNED); 431 *uc = p->p_tracecred; 432 p->p_tracecred = NULL; 433 if (vp != NULL) 434 *vp = p->p_tracevp; 435 p->p_tracevp = NULL; 436 p->p_traceflag = 0; 437 while ((req = STAILQ_FIRST(&p->p_ktr)) != NULL) { 438 STAILQ_REMOVE_HEAD(&p->p_ktr, ktr_list); 439 ktr_freerequest_locked(req); 440 } 441 } 442 443 void 444 ktrsyscall(int code, int narg, register_t args[]) 445 { 446 struct ktr_request *req; 447 struct ktr_syscall *ktp; 448 size_t buflen; 449 char *buf = NULL; 450 451 buflen = sizeof(register_t) * narg; 452 if (buflen > 0) { 453 buf = malloc(buflen, M_KTRACE, M_WAITOK); 454 bcopy(args, buf, buflen); 455 } 456 req = ktr_getrequest(KTR_SYSCALL); 457 if (req == NULL) { 458 if (buf != NULL) 459 free(buf, M_KTRACE); 460 return; 461 } 462 ktp = &req->ktr_data.ktr_syscall; 463 ktp->ktr_code = code; 464 ktp->ktr_narg = narg; 465 if (buflen > 0) { 466 req->ktr_header.ktr_len = buflen; 467 req->ktr_buffer = buf; 468 } 469 ktr_submitrequest(curthread, req); 470 } 471 472 void 473 ktrsysret(int code, int error, 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 MPASS(p2->p_tracevp == NULL); 576 MPASS(p2->p_traceflag == 0); 577 578 if (p1->p_traceflag == 0) 579 return; 580 581 PROC_LOCK(p1); 582 mtx_lock(&ktrace_mtx); 583 if (p1->p_traceflag & KTRFAC_INHERIT) { 584 p2->p_traceflag = p1->p_traceflag; 585 if ((p2->p_tracevp = p1->p_tracevp) != NULL) { 586 VREF(p2->p_tracevp); 587 KASSERT(p1->p_tracecred != NULL, 588 ("ktrace vnode with no cred")); 589 p2->p_tracecred = crhold(p1->p_tracecred); 590 } 591 } 592 mtx_unlock(&ktrace_mtx); 593 PROC_UNLOCK(p1); 594 595 ktrprocctor(p2); 596 } 597 598 /* 599 * When a thread returns, drain any asynchronous records generated by the 600 * system call. 601 */ 602 void 603 ktruserret(struct thread *td) 604 { 605 606 ktrace_enter(td); 607 sx_xlock(&ktrace_sx); 608 ktr_drain(td); 609 sx_xunlock(&ktrace_sx); 610 ktrace_exit(td); 611 } 612 613 void 614 ktrnamei(path) 615 char *path; 616 { 617 struct ktr_request *req; 618 int namelen; 619 char *buf = NULL; 620 621 namelen = strlen(path); 622 if (namelen > 0) { 623 buf = malloc(namelen, M_KTRACE, M_WAITOK); 624 bcopy(path, buf, namelen); 625 } 626 req = ktr_getrequest(KTR_NAMEI); 627 if (req == NULL) { 628 if (buf != NULL) 629 free(buf, M_KTRACE); 630 return; 631 } 632 if (namelen > 0) { 633 req->ktr_header.ktr_len = namelen; 634 req->ktr_buffer = buf; 635 } 636 ktr_submitrequest(curthread, req); 637 } 638 639 void 640 ktrsysctl(int *name, u_int namelen) 641 { 642 struct ktr_request *req; 643 u_int mib[CTL_MAXNAME + 2]; 644 char *mibname; 645 size_t mibnamelen; 646 int error; 647 648 /* Lookup name of mib. */ 649 KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long")); 650 mib[0] = 0; 651 mib[1] = 1; 652 bcopy(name, mib + 2, namelen * sizeof(*name)); 653 mibnamelen = 128; 654 mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK); 655 error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen, 656 NULL, 0, &mibnamelen, 0); 657 if (error) { 658 free(mibname, M_KTRACE); 659 return; 660 } 661 req = ktr_getrequest(KTR_SYSCTL); 662 if (req == NULL) { 663 free(mibname, M_KTRACE); 664 return; 665 } 666 req->ktr_header.ktr_len = mibnamelen; 667 req->ktr_buffer = mibname; 668 ktr_submitrequest(curthread, req); 669 } 670 671 void 672 ktrgenio(int fd, enum uio_rw rw, struct uio *uio, int error) 673 { 674 struct ktr_request *req; 675 struct ktr_genio *ktg; 676 int datalen; 677 char *buf; 678 679 if (error) { 680 free(uio, M_IOV); 681 return; 682 } 683 uio->uio_offset = 0; 684 uio->uio_rw = UIO_WRITE; 685 datalen = MIN(uio->uio_resid, ktr_geniosize); 686 buf = malloc(datalen, M_KTRACE, M_WAITOK); 687 error = uiomove(buf, datalen, uio); 688 free(uio, M_IOV); 689 if (error) { 690 free(buf, M_KTRACE); 691 return; 692 } 693 req = ktr_getrequest(KTR_GENIO); 694 if (req == NULL) { 695 free(buf, M_KTRACE); 696 return; 697 } 698 ktg = &req->ktr_data.ktr_genio; 699 ktg->ktr_fd = fd; 700 ktg->ktr_rw = rw; 701 req->ktr_header.ktr_len = datalen; 702 req->ktr_buffer = buf; 703 ktr_submitrequest(curthread, req); 704 } 705 706 void 707 ktrpsig(int sig, sig_t action, sigset_t *mask, int code) 708 { 709 struct thread *td = curthread; 710 struct ktr_request *req; 711 struct ktr_psig *kp; 712 713 req = ktr_getrequest(KTR_PSIG); 714 if (req == NULL) 715 return; 716 kp = &req->ktr_data.ktr_psig; 717 kp->signo = (char)sig; 718 kp->action = action; 719 kp->mask = *mask; 720 kp->code = code; 721 ktr_enqueuerequest(td, req); 722 ktrace_exit(td); 723 } 724 725 void 726 ktrcsw(int out, int user, const char *wmesg) 727 { 728 struct thread *td = curthread; 729 struct ktr_request *req; 730 struct ktr_csw *kc; 731 732 req = ktr_getrequest(KTR_CSW); 733 if (req == NULL) 734 return; 735 kc = &req->ktr_data.ktr_csw; 736 kc->out = out; 737 kc->user = user; 738 if (wmesg != NULL) 739 strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg)); 740 else 741 bzero(kc->wmesg, sizeof(kc->wmesg)); 742 ktr_enqueuerequest(td, req); 743 ktrace_exit(td); 744 } 745 746 void 747 ktrstruct(const char *name, const void *data, size_t datalen) 748 { 749 struct ktr_request *req; 750 char *buf; 751 size_t buflen, namelen; 752 753 if (data == NULL) 754 datalen = 0; 755 namelen = strlen(name) + 1; 756 buflen = namelen + datalen; 757 buf = malloc(buflen, M_KTRACE, M_WAITOK); 758 strcpy(buf, name); 759 bcopy(data, buf + namelen, datalen); 760 if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) { 761 free(buf, M_KTRACE); 762 return; 763 } 764 req->ktr_buffer = buf; 765 req->ktr_header.ktr_len = buflen; 766 ktr_submitrequest(curthread, req); 767 } 768 769 void 770 ktrstructarray(const char *name, enum uio_seg seg, const void *data, 771 int num_items, size_t struct_size) 772 { 773 struct ktr_request *req; 774 struct ktr_struct_array *ksa; 775 char *buf; 776 size_t buflen, datalen, namelen; 777 int max_items; 778 779 /* Trim array length to genio size. */ 780 max_items = ktr_geniosize / struct_size; 781 if (num_items > max_items) { 782 if (max_items == 0) 783 num_items = 1; 784 else 785 num_items = max_items; 786 } 787 datalen = num_items * struct_size; 788 789 if (data == NULL) 790 datalen = 0; 791 792 namelen = strlen(name) + 1; 793 buflen = namelen + datalen; 794 buf = malloc(buflen, M_KTRACE, M_WAITOK); 795 strcpy(buf, name); 796 if (seg == UIO_SYSSPACE) 797 bcopy(data, buf + namelen, datalen); 798 else { 799 if (copyin(data, buf + namelen, datalen) != 0) { 800 free(buf, M_KTRACE); 801 return; 802 } 803 } 804 if ((req = ktr_getrequest(KTR_STRUCT_ARRAY)) == NULL) { 805 free(buf, M_KTRACE); 806 return; 807 } 808 ksa = &req->ktr_data.ktr_struct_array; 809 ksa->struct_size = struct_size; 810 req->ktr_buffer = buf; 811 req->ktr_header.ktr_len = buflen; 812 ktr_submitrequest(curthread, req); 813 } 814 815 void 816 ktrcapfail(enum ktr_cap_fail_type type, const cap_rights_t *needed, 817 const cap_rights_t *held) 818 { 819 struct thread *td = curthread; 820 struct ktr_request *req; 821 struct ktr_cap_fail *kcf; 822 823 req = ktr_getrequest(KTR_CAPFAIL); 824 if (req == NULL) 825 return; 826 kcf = &req->ktr_data.ktr_cap_fail; 827 kcf->cap_type = type; 828 if (needed != NULL) 829 kcf->cap_needed = *needed; 830 else 831 cap_rights_init(&kcf->cap_needed); 832 if (held != NULL) 833 kcf->cap_held = *held; 834 else 835 cap_rights_init(&kcf->cap_held); 836 ktr_enqueuerequest(td, req); 837 ktrace_exit(td); 838 } 839 840 void 841 ktrfault(vm_offset_t vaddr, int type) 842 { 843 struct thread *td = curthread; 844 struct ktr_request *req; 845 struct ktr_fault *kf; 846 847 req = ktr_getrequest(KTR_FAULT); 848 if (req == NULL) 849 return; 850 kf = &req->ktr_data.ktr_fault; 851 kf->vaddr = vaddr; 852 kf->type = type; 853 ktr_enqueuerequest(td, req); 854 ktrace_exit(td); 855 } 856 857 void 858 ktrfaultend(int result) 859 { 860 struct thread *td = curthread; 861 struct ktr_request *req; 862 struct ktr_faultend *kf; 863 864 req = ktr_getrequest(KTR_FAULTEND); 865 if (req == NULL) 866 return; 867 kf = &req->ktr_data.ktr_faultend; 868 kf->result = result; 869 ktr_enqueuerequest(td, req); 870 ktrace_exit(td); 871 } 872 #endif /* KTRACE */ 873 874 /* Interface and common routines */ 875 876 #ifndef _SYS_SYSPROTO_H_ 877 struct ktrace_args { 878 char *fname; 879 int ops; 880 int facs; 881 int pid; 882 }; 883 #endif 884 /* ARGSUSED */ 885 int 886 sys_ktrace(struct thread *td, struct ktrace_args *uap) 887 { 888 #ifdef KTRACE 889 struct vnode *vp = NULL; 890 struct proc *p; 891 struct pgrp *pg; 892 int facs = uap->facs & ~KTRFAC_ROOT; 893 int ops = KTROP(uap->ops); 894 int descend = uap->ops & KTRFLAG_DESCEND; 895 int nfound, ret = 0; 896 int flags, error = 0; 897 struct nameidata nd; 898 struct ucred *cred; 899 900 /* 901 * Need something to (un)trace. 902 */ 903 if (ops != KTROP_CLEARFILE && facs == 0) 904 return (EINVAL); 905 906 ktrace_enter(td); 907 if (ops != KTROP_CLEAR) { 908 /* 909 * an operation which requires a file argument. 910 */ 911 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td); 912 flags = FREAD | FWRITE | O_NOFOLLOW; 913 error = vn_open(&nd, &flags, 0, NULL); 914 if (error) { 915 ktrace_exit(td); 916 return (error); 917 } 918 NDFREE(&nd, NDF_ONLY_PNBUF); 919 vp = nd.ni_vp; 920 VOP_UNLOCK(vp, 0); 921 if (vp->v_type != VREG) { 922 (void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td); 923 ktrace_exit(td); 924 return (EACCES); 925 } 926 } 927 /* 928 * Clear all uses of the tracefile. 929 */ 930 if (ops == KTROP_CLEARFILE) { 931 int vrele_count; 932 933 vrele_count = 0; 934 sx_slock(&allproc_lock); 935 FOREACH_PROC_IN_SYSTEM(p) { 936 PROC_LOCK(p); 937 if (p->p_tracevp == vp) { 938 if (ktrcanset(td, p)) { 939 mtx_lock(&ktrace_mtx); 940 ktr_freeproc(p, &cred, NULL); 941 mtx_unlock(&ktrace_mtx); 942 vrele_count++; 943 crfree(cred); 944 } else 945 error = EPERM; 946 } 947 PROC_UNLOCK(p); 948 } 949 sx_sunlock(&allproc_lock); 950 if (vrele_count > 0) { 951 while (vrele_count-- > 0) 952 vrele(vp); 953 } 954 goto done; 955 } 956 /* 957 * do it 958 */ 959 sx_slock(&proctree_lock); 960 if (uap->pid < 0) { 961 /* 962 * by process group 963 */ 964 pg = pgfind(-uap->pid); 965 if (pg == NULL) { 966 sx_sunlock(&proctree_lock); 967 error = ESRCH; 968 goto done; 969 } 970 /* 971 * ktrops() may call vrele(). Lock pg_members 972 * by the proctree_lock rather than pg_mtx. 973 */ 974 PGRP_UNLOCK(pg); 975 nfound = 0; 976 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 977 PROC_LOCK(p); 978 if (p->p_state == PRS_NEW || 979 p_cansee(td, p) != 0) { 980 PROC_UNLOCK(p); 981 continue; 982 } 983 nfound++; 984 if (descend) 985 ret |= ktrsetchildren(td, p, ops, facs, vp); 986 else 987 ret |= ktrops(td, p, ops, facs, vp); 988 } 989 if (nfound == 0) { 990 sx_sunlock(&proctree_lock); 991 error = ESRCH; 992 goto done; 993 } 994 } else { 995 /* 996 * by pid 997 */ 998 p = pfind(uap->pid); 999 if (p == NULL) 1000 error = ESRCH; 1001 else 1002 error = p_cansee(td, p); 1003 if (error) { 1004 if (p != NULL) 1005 PROC_UNLOCK(p); 1006 sx_sunlock(&proctree_lock); 1007 goto done; 1008 } 1009 if (descend) 1010 ret |= ktrsetchildren(td, p, ops, facs, vp); 1011 else 1012 ret |= ktrops(td, p, ops, facs, vp); 1013 } 1014 sx_sunlock(&proctree_lock); 1015 if (!ret) 1016 error = EPERM; 1017 done: 1018 if (vp != NULL) 1019 (void) vn_close(vp, FWRITE, td->td_ucred, td); 1020 ktrace_exit(td); 1021 return (error); 1022 #else /* !KTRACE */ 1023 return (ENOSYS); 1024 #endif /* KTRACE */ 1025 } 1026 1027 /* ARGSUSED */ 1028 int 1029 sys_utrace(struct thread *td, struct utrace_args *uap) 1030 { 1031 1032 #ifdef KTRACE 1033 struct ktr_request *req; 1034 void *cp; 1035 int error; 1036 1037 if (!KTRPOINT(td, KTR_USER)) 1038 return (0); 1039 if (uap->len > KTR_USER_MAXLEN) 1040 return (EINVAL); 1041 cp = malloc(uap->len, M_KTRACE, M_WAITOK); 1042 error = copyin(uap->addr, cp, uap->len); 1043 if (error) { 1044 free(cp, M_KTRACE); 1045 return (error); 1046 } 1047 req = ktr_getrequest(KTR_USER); 1048 if (req == NULL) { 1049 free(cp, M_KTRACE); 1050 return (ENOMEM); 1051 } 1052 req->ktr_buffer = cp; 1053 req->ktr_header.ktr_len = uap->len; 1054 ktr_submitrequest(td, req); 1055 return (0); 1056 #else /* !KTRACE */ 1057 return (ENOSYS); 1058 #endif /* KTRACE */ 1059 } 1060 1061 #ifdef KTRACE 1062 static int 1063 ktrops(struct thread *td, struct proc *p, int ops, int facs, struct vnode *vp) 1064 { 1065 struct vnode *tracevp = NULL; 1066 struct ucred *tracecred = NULL; 1067 1068 PROC_LOCK_ASSERT(p, MA_OWNED); 1069 if (!ktrcanset(td, p)) { 1070 PROC_UNLOCK(p); 1071 return (0); 1072 } 1073 if (p->p_flag & P_WEXIT) { 1074 /* If the process is exiting, just ignore it. */ 1075 PROC_UNLOCK(p); 1076 return (1); 1077 } 1078 mtx_lock(&ktrace_mtx); 1079 if (ops == KTROP_SET) { 1080 if (p->p_tracevp != vp) { 1081 /* 1082 * if trace file already in use, relinquish below 1083 */ 1084 tracevp = p->p_tracevp; 1085 VREF(vp); 1086 p->p_tracevp = vp; 1087 } 1088 if (p->p_tracecred != td->td_ucred) { 1089 tracecred = p->p_tracecred; 1090 p->p_tracecred = crhold(td->td_ucred); 1091 } 1092 p->p_traceflag |= facs; 1093 if (priv_check(td, PRIV_KTRACE) == 0) 1094 p->p_traceflag |= KTRFAC_ROOT; 1095 } else { 1096 /* KTROP_CLEAR */ 1097 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) 1098 /* no more tracing */ 1099 ktr_freeproc(p, &tracecred, &tracevp); 1100 } 1101 mtx_unlock(&ktrace_mtx); 1102 if ((p->p_traceflag & KTRFAC_MASK) != 0) 1103 ktrprocctor_entered(td, p); 1104 PROC_UNLOCK(p); 1105 if (tracevp != NULL) 1106 vrele(tracevp); 1107 if (tracecred != NULL) 1108 crfree(tracecred); 1109 1110 return (1); 1111 } 1112 1113 static int 1114 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs, 1115 struct vnode *vp) 1116 { 1117 struct proc *p; 1118 int ret = 0; 1119 1120 p = top; 1121 PROC_LOCK_ASSERT(p, MA_OWNED); 1122 sx_assert(&proctree_lock, SX_LOCKED); 1123 for (;;) { 1124 ret |= ktrops(td, p, ops, facs, vp); 1125 /* 1126 * If this process has children, descend to them next, 1127 * otherwise do any siblings, and if done with this level, 1128 * follow back up the tree (but not past top). 1129 */ 1130 if (!LIST_EMPTY(&p->p_children)) 1131 p = LIST_FIRST(&p->p_children); 1132 else for (;;) { 1133 if (p == top) 1134 return (ret); 1135 if (LIST_NEXT(p, p_sibling)) { 1136 p = LIST_NEXT(p, p_sibling); 1137 break; 1138 } 1139 p = p->p_pptr; 1140 } 1141 PROC_LOCK(p); 1142 } 1143 /*NOTREACHED*/ 1144 } 1145 1146 static void 1147 ktr_writerequest(struct thread *td, struct ktr_request *req) 1148 { 1149 struct ktr_header *kth; 1150 struct vnode *vp; 1151 struct proc *p; 1152 struct ucred *cred; 1153 struct uio auio; 1154 struct iovec aiov[3]; 1155 struct mount *mp; 1156 int datalen, buflen, vrele_count; 1157 int error; 1158 1159 /* 1160 * We hold the vnode and credential for use in I/O in case ktrace is 1161 * disabled on the process as we write out the request. 1162 * 1163 * XXXRW: This is not ideal: we could end up performing a write after 1164 * the vnode has been closed. 1165 */ 1166 mtx_lock(&ktrace_mtx); 1167 vp = td->td_proc->p_tracevp; 1168 cred = td->td_proc->p_tracecred; 1169 1170 /* 1171 * If vp is NULL, the vp has been cleared out from under this 1172 * request, so just drop it. Make sure the credential and vnode are 1173 * in sync: we should have both or neither. 1174 */ 1175 if (vp == NULL) { 1176 KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL")); 1177 mtx_unlock(&ktrace_mtx); 1178 return; 1179 } 1180 VREF(vp); 1181 KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL")); 1182 crhold(cred); 1183 mtx_unlock(&ktrace_mtx); 1184 1185 kth = &req->ktr_header; 1186 KASSERT(((u_short)kth->ktr_type & ~KTR_DROP) < nitems(data_lengths), 1187 ("data_lengths array overflow")); 1188 datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_DROP]; 1189 buflen = kth->ktr_len; 1190 auio.uio_iov = &aiov[0]; 1191 auio.uio_offset = 0; 1192 auio.uio_segflg = UIO_SYSSPACE; 1193 auio.uio_rw = UIO_WRITE; 1194 aiov[0].iov_base = (caddr_t)kth; 1195 aiov[0].iov_len = sizeof(struct ktr_header); 1196 auio.uio_resid = sizeof(struct ktr_header); 1197 auio.uio_iovcnt = 1; 1198 auio.uio_td = td; 1199 if (datalen != 0) { 1200 aiov[1].iov_base = (caddr_t)&req->ktr_data; 1201 aiov[1].iov_len = datalen; 1202 auio.uio_resid += datalen; 1203 auio.uio_iovcnt++; 1204 kth->ktr_len += datalen; 1205 } 1206 if (buflen != 0) { 1207 KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write")); 1208 aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer; 1209 aiov[auio.uio_iovcnt].iov_len = buflen; 1210 auio.uio_resid += buflen; 1211 auio.uio_iovcnt++; 1212 } 1213 1214 vn_start_write(vp, &mp, V_WAIT); 1215 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1216 #ifdef MAC 1217 error = mac_vnode_check_write(cred, NOCRED, vp); 1218 if (error == 0) 1219 #endif 1220 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred); 1221 VOP_UNLOCK(vp, 0); 1222 vn_finished_write(mp); 1223 crfree(cred); 1224 if (!error) { 1225 vrele(vp); 1226 return; 1227 } 1228 1229 /* 1230 * If error encountered, give up tracing on this vnode. We defer 1231 * all the vrele()'s on the vnode until after we are finished walking 1232 * the various lists to avoid needlessly holding locks. 1233 * NB: at this point we still hold the vnode reference that must 1234 * not go away as we need the valid vnode to compare with. Thus let 1235 * vrele_count start at 1 and the reference will be freed 1236 * by the loop at the end after our last use of vp. 1237 */ 1238 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 1239 error); 1240 vrele_count = 1; 1241 /* 1242 * First, clear this vnode from being used by any processes in the 1243 * system. 1244 * XXX - If one process gets an EPERM writing to the vnode, should 1245 * we really do this? Other processes might have suitable 1246 * credentials for the operation. 1247 */ 1248 cred = NULL; 1249 sx_slock(&allproc_lock); 1250 FOREACH_PROC_IN_SYSTEM(p) { 1251 PROC_LOCK(p); 1252 if (p->p_tracevp == vp) { 1253 mtx_lock(&ktrace_mtx); 1254 ktr_freeproc(p, &cred, NULL); 1255 mtx_unlock(&ktrace_mtx); 1256 vrele_count++; 1257 } 1258 PROC_UNLOCK(p); 1259 if (cred != NULL) { 1260 crfree(cred); 1261 cred = NULL; 1262 } 1263 } 1264 sx_sunlock(&allproc_lock); 1265 1266 while (vrele_count-- > 0) 1267 vrele(vp); 1268 } 1269 1270 /* 1271 * Return true if caller has permission to set the ktracing state 1272 * of target. Essentially, the target can't possess any 1273 * more permissions than the caller. KTRFAC_ROOT signifies that 1274 * root previously set the tracing status on the target process, and 1275 * so, only root may further change it. 1276 */ 1277 static int 1278 ktrcanset(struct thread *td, struct proc *targetp) 1279 { 1280 1281 PROC_LOCK_ASSERT(targetp, MA_OWNED); 1282 if (targetp->p_traceflag & KTRFAC_ROOT && 1283 priv_check(td, PRIV_KTRACE)) 1284 return (0); 1285 1286 if (p_candebug(td, targetp) != 0) 1287 return (0); 1288 1289 return (1); 1290 } 1291 1292 #endif /* KTRACE */ 1293