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/9.2/sys/kern/kern_ktrace.c 267018 2014-06-03 19:03:11Z delphij $"); 36 37 #include "opt_ktrace.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/fcntl.h> 42 #include <sys/kernel.h> 43 #include <sys/kthread.h> 44 #include <sys/lock.h> 45 #include <sys/mutex.h> 46 #include <sys/malloc.h> 47 #include <sys/mount.h> 48 #include <sys/namei.h> 49 #include <sys/priv.h> 50 #include <sys/proc.h> 51 #include <sys/unistd.h> 52 #include <sys/vnode.h> 53 #include <sys/socket.h> 54 #include <sys/stat.h> 55 #include <sys/ktrace.h> 56 #include <sys/sx.h> 57 #include <sys/sysctl.h> 58 #include <sys/sysent.h> 59 #include <sys/syslog.h> 60 #include <sys/sysproto.h> 61 62 #include <security/mac/mac_framework.h> 63 64 /* 65 * The ktrace facility allows the tracing of certain key events in user space 66 * processes, such as system calls, signal delivery, context switches, and 67 * user generated events using utrace(2). It works by streaming event 68 * records and data to a vnode associated with the process using the 69 * ktrace(2) system call. In general, records can be written directly from 70 * the context that generates the event. One important exception to this is 71 * during a context switch, where sleeping is not permitted. To handle this 72 * case, trace events are generated using in-kernel ktr_request records, and 73 * then delivered to disk at a convenient moment -- either immediately, the 74 * next traceable event, at system call return, or at process exit. 75 * 76 * When dealing with multiple threads or processes writing to the same event 77 * log, ordering guarantees are weak: specifically, if an event has multiple 78 * records (i.e., system call enter and return), they may be interlaced with 79 * records from another event. Process and thread ID information is provided 80 * in the record, and user applications can de-interlace events if required. 81 */ 82 83 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 84 85 #ifdef KTRACE 86 87 FEATURE(ktrace, "Kernel support for system-call tracing"); 88 89 #ifndef KTRACE_REQUEST_POOL 90 #define KTRACE_REQUEST_POOL 100 91 #endif 92 93 struct ktr_request { 94 struct ktr_header ktr_header; 95 void *ktr_buffer; 96 union { 97 struct ktr_proc_ctor ktr_proc_ctor; 98 struct ktr_syscall ktr_syscall; 99 struct ktr_sysret ktr_sysret; 100 struct ktr_genio ktr_genio; 101 struct ktr_psig ktr_psig; 102 struct ktr_csw ktr_csw; 103 struct ktr_fault ktr_fault; 104 struct ktr_faultend ktr_faultend; 105 } ktr_data; 106 STAILQ_ENTRY(ktr_request) ktr_list; 107 }; 108 109 static int data_lengths[] = { 110 0, /* none */ 111 offsetof(struct ktr_syscall, ktr_args), /* KTR_SYSCALL */ 112 sizeof(struct ktr_sysret), /* KTR_SYSRET */ 113 0, /* KTR_NAMEI */ 114 sizeof(struct ktr_genio), /* KTR_GENIO */ 115 sizeof(struct ktr_psig), /* KTR_PSIG */ 116 sizeof(struct ktr_csw), /* KTR_CSW */ 117 0, /* KTR_USER */ 118 0, /* KTR_STRUCT */ 119 0, /* KTR_SYSCTL */ 120 sizeof(struct ktr_proc_ctor), /* KTR_PROCCTOR */ 121 0, /* KTR_PROCDTOR */ 122 0, /* unused */ 123 sizeof(struct ktr_fault), /* KTR_FAULT */ 124 sizeof(struct ktr_faultend), /* KTR_FAULTEND */ 125 }; 126 127 static STAILQ_HEAD(, ktr_request) ktr_free; 128 129 static SYSCTL_NODE(_kern, OID_AUTO, ktrace, CTLFLAG_RD, 0, "KTRACE options"); 130 131 static u_int ktr_requestpool = KTRACE_REQUEST_POOL; 132 TUNABLE_INT("kern.ktrace.request_pool", &ktr_requestpool); 133 134 static u_int ktr_geniosize = PAGE_SIZE; 135 TUNABLE_INT("kern.ktrace.genio_size", &ktr_geniosize); 136 SYSCTL_UINT(_kern_ktrace, OID_AUTO, genio_size, CTLFLAG_RW, &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 int vfslocked; 515 516 p = td->td_proc; 517 if (p->p_traceflag == 0) 518 return; 519 520 ktrace_enter(td); 521 req = ktr_getrequest_entered(td, KTR_PROCDTOR); 522 if (req != NULL) 523 ktr_enqueuerequest(td, req); 524 sx_xlock(&ktrace_sx); 525 ktr_drain(td); 526 sx_xunlock(&ktrace_sx); 527 PROC_LOCK(p); 528 mtx_lock(&ktrace_mtx); 529 ktr_freeproc(p, &cred, &vp); 530 mtx_unlock(&ktrace_mtx); 531 PROC_UNLOCK(p); 532 if (vp != NULL) { 533 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 534 vrele(vp); 535 VFS_UNLOCK_GIANT(vfslocked); 536 } 537 if (cred != NULL) 538 crfree(cred); 539 ktrace_exit(td); 540 } 541 542 static void 543 ktrprocctor_entered(struct thread *td, struct proc *p) 544 { 545 struct ktr_proc_ctor *ktp; 546 struct ktr_request *req; 547 struct thread *td2; 548 549 ktrace_assert(td); 550 td2 = FIRST_THREAD_IN_PROC(p); 551 req = ktr_getrequest_entered(td2, KTR_PROCCTOR); 552 if (req == NULL) 553 return; 554 ktp = &req->ktr_data.ktr_proc_ctor; 555 ktp->sv_flags = p->p_sysent->sv_flags; 556 ktr_enqueuerequest(td2, req); 557 } 558 559 void 560 ktrprocctor(struct proc *p) 561 { 562 struct thread *td = curthread; 563 564 if ((p->p_traceflag & KTRFAC_MASK) == 0) 565 return; 566 567 ktrace_enter(td); 568 ktrprocctor_entered(td, p); 569 ktrace_exit(td); 570 } 571 572 /* 573 * When a process forks, enable tracing in the new process if needed. 574 */ 575 void 576 ktrprocfork(struct proc *p1, struct proc *p2) 577 { 578 579 PROC_LOCK(p1); 580 mtx_lock(&ktrace_mtx); 581 KASSERT(p2->p_tracevp == NULL, ("new process has a ktrace vnode")); 582 if (p1->p_traceflag & KTRFAC_INHERIT) { 583 p2->p_traceflag = p1->p_traceflag; 584 if ((p2->p_tracevp = p1->p_tracevp) != NULL) { 585 VREF(p2->p_tracevp); 586 KASSERT(p1->p_tracecred != NULL, 587 ("ktrace vnode with no cred")); 588 p2->p_tracecred = crhold(p1->p_tracecred); 589 } 590 } 591 mtx_unlock(&ktrace_mtx); 592 PROC_UNLOCK(p1); 593 594 ktrprocctor(p2); 595 } 596 597 /* 598 * When a thread returns, drain any asynchronous records generated by the 599 * system call. 600 */ 601 void 602 ktruserret(struct thread *td) 603 { 604 605 ktrace_enter(td); 606 sx_xlock(&ktrace_sx); 607 ktr_drain(td); 608 sx_xunlock(&ktrace_sx); 609 ktrace_exit(td); 610 } 611 612 void 613 ktrnamei(path) 614 char *path; 615 { 616 struct ktr_request *req; 617 int namelen; 618 char *buf = NULL; 619 620 namelen = strlen(path); 621 if (namelen > 0) { 622 buf = malloc(namelen, M_KTRACE, M_WAITOK); 623 bcopy(path, buf, namelen); 624 } 625 req = ktr_getrequest(KTR_NAMEI); 626 if (req == NULL) { 627 if (buf != NULL) 628 free(buf, M_KTRACE); 629 return; 630 } 631 if (namelen > 0) { 632 req->ktr_header.ktr_len = namelen; 633 req->ktr_buffer = buf; 634 } 635 ktr_submitrequest(curthread, req); 636 } 637 638 void 639 ktrsysctl(name, namelen) 640 int *name; 641 u_int namelen; 642 { 643 struct ktr_request *req; 644 u_int mib[CTL_MAXNAME + 2]; 645 char *mibname; 646 size_t mibnamelen; 647 int error; 648 649 /* Lookup name of mib. */ 650 KASSERT(namelen <= CTL_MAXNAME, ("sysctl MIB too long")); 651 mib[0] = 0; 652 mib[1] = 1; 653 bcopy(name, mib + 2, namelen * sizeof(*name)); 654 mibnamelen = 128; 655 mibname = malloc(mibnamelen, M_KTRACE, M_WAITOK); 656 error = kernel_sysctl(curthread, mib, namelen + 2, mibname, &mibnamelen, 657 NULL, 0, &mibnamelen, 0); 658 if (error) { 659 free(mibname, M_KTRACE); 660 return; 661 } 662 req = ktr_getrequest(KTR_SYSCTL); 663 if (req == NULL) { 664 free(mibname, M_KTRACE); 665 return; 666 } 667 req->ktr_header.ktr_len = mibnamelen; 668 req->ktr_buffer = mibname; 669 ktr_submitrequest(curthread, req); 670 } 671 672 void 673 ktrgenio(fd, rw, uio, error) 674 int fd; 675 enum uio_rw rw; 676 struct uio *uio; 677 int error; 678 { 679 struct ktr_request *req; 680 struct ktr_genio *ktg; 681 int datalen; 682 char *buf; 683 684 if (error) { 685 free(uio, M_IOV); 686 return; 687 } 688 uio->uio_offset = 0; 689 uio->uio_rw = UIO_WRITE; 690 datalen = MIN(uio->uio_resid, ktr_geniosize); 691 buf = malloc(datalen, M_KTRACE, M_WAITOK); 692 error = uiomove(buf, datalen, uio); 693 free(uio, M_IOV); 694 if (error) { 695 free(buf, M_KTRACE); 696 return; 697 } 698 req = ktr_getrequest(KTR_GENIO); 699 if (req == NULL) { 700 free(buf, M_KTRACE); 701 return; 702 } 703 ktg = &req->ktr_data.ktr_genio; 704 ktg->ktr_fd = fd; 705 ktg->ktr_rw = rw; 706 req->ktr_header.ktr_len = datalen; 707 req->ktr_buffer = buf; 708 ktr_submitrequest(curthread, req); 709 } 710 711 void 712 ktrpsig(sig, action, mask, code) 713 int sig; 714 sig_t action; 715 sigset_t *mask; 716 int code; 717 { 718 struct thread *td = curthread; 719 struct ktr_request *req; 720 struct ktr_psig *kp; 721 722 req = ktr_getrequest(KTR_PSIG); 723 if (req == NULL) 724 return; 725 kp = &req->ktr_data.ktr_psig; 726 kp->signo = (char)sig; 727 kp->action = action; 728 kp->mask = *mask; 729 kp->code = code; 730 ktr_enqueuerequest(td, req); 731 ktrace_exit(td); 732 } 733 734 void 735 ktrcsw(out, user, wmesg) 736 int out, user; 737 const char *wmesg; 738 { 739 struct thread *td = curthread; 740 struct ktr_request *req; 741 struct ktr_csw *kc; 742 743 req = ktr_getrequest(KTR_CSW); 744 if (req == NULL) 745 return; 746 kc = &req->ktr_data.ktr_csw; 747 kc->out = out; 748 kc->user = user; 749 if (wmesg != NULL) 750 strlcpy(kc->wmesg, wmesg, sizeof(kc->wmesg)); 751 else 752 bzero(kc->wmesg, sizeof(kc->wmesg)); 753 ktr_enqueuerequest(td, req); 754 ktrace_exit(td); 755 } 756 757 void 758 ktrstruct(name, data, datalen) 759 const char *name; 760 void *data; 761 size_t datalen; 762 { 763 struct ktr_request *req; 764 char *buf = NULL; 765 size_t buflen; 766 767 if (!data) 768 datalen = 0; 769 buflen = strlen(name) + 1 + datalen; 770 buf = malloc(buflen, M_KTRACE, M_WAITOK); 771 strcpy(buf, name); 772 bcopy(data, buf + strlen(name) + 1, datalen); 773 if ((req = ktr_getrequest(KTR_STRUCT)) == NULL) { 774 free(buf, M_KTRACE); 775 return; 776 } 777 req->ktr_buffer = buf; 778 req->ktr_header.ktr_len = buflen; 779 ktr_submitrequest(curthread, req); 780 } 781 782 void 783 ktrfault(vaddr, type) 784 vm_offset_t vaddr; 785 int type; 786 { 787 struct thread *td = curthread; 788 struct ktr_request *req; 789 struct ktr_fault *kf; 790 791 req = ktr_getrequest(KTR_FAULT); 792 if (req == NULL) 793 return; 794 kf = &req->ktr_data.ktr_fault; 795 kf->vaddr = vaddr; 796 kf->type = type; 797 ktr_enqueuerequest(td, req); 798 ktrace_exit(td); 799 } 800 801 void 802 ktrfaultend(result) 803 int result; 804 { 805 struct thread *td = curthread; 806 struct ktr_request *req; 807 struct ktr_faultend *kf; 808 809 req = ktr_getrequest(KTR_FAULTEND); 810 if (req == NULL) 811 return; 812 kf = &req->ktr_data.ktr_faultend; 813 kf->result = result; 814 ktr_enqueuerequest(td, req); 815 ktrace_exit(td); 816 } 817 #endif /* KTRACE */ 818 819 /* Interface and common routines */ 820 821 #ifndef _SYS_SYSPROTO_H_ 822 struct ktrace_args { 823 char *fname; 824 int ops; 825 int facs; 826 int pid; 827 }; 828 #endif 829 /* ARGSUSED */ 830 int 831 sys_ktrace(td, uap) 832 struct thread *td; 833 register struct ktrace_args *uap; 834 { 835 #ifdef KTRACE 836 register struct vnode *vp = NULL; 837 register struct proc *p; 838 struct pgrp *pg; 839 int facs = uap->facs & ~KTRFAC_ROOT; 840 int ops = KTROP(uap->ops); 841 int descend = uap->ops & KTRFLAG_DESCEND; 842 int nfound, ret = 0; 843 int flags, error = 0, vfslocked; 844 struct nameidata nd; 845 struct ucred *cred; 846 847 /* 848 * Need something to (un)trace. 849 */ 850 if (ops != KTROP_CLEARFILE && facs == 0) 851 return (EINVAL); 852 853 ktrace_enter(td); 854 if (ops != KTROP_CLEAR) { 855 /* 856 * an operation which requires a file argument. 857 */ 858 NDINIT(&nd, LOOKUP, NOFOLLOW | MPSAFE, UIO_USERSPACE, 859 uap->fname, td); 860 flags = FREAD | FWRITE | O_NOFOLLOW; 861 error = vn_open(&nd, &flags, 0, NULL); 862 if (error) { 863 ktrace_exit(td); 864 return (error); 865 } 866 vfslocked = NDHASGIANT(&nd); 867 NDFREE(&nd, NDF_ONLY_PNBUF); 868 vp = nd.ni_vp; 869 VOP_UNLOCK(vp, 0); 870 if (vp->v_type != VREG) { 871 (void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td); 872 VFS_UNLOCK_GIANT(vfslocked); 873 ktrace_exit(td); 874 return (EACCES); 875 } 876 VFS_UNLOCK_GIANT(vfslocked); 877 } 878 /* 879 * Clear all uses of the tracefile. 880 */ 881 if (ops == KTROP_CLEARFILE) { 882 int vrele_count; 883 884 vrele_count = 0; 885 sx_slock(&allproc_lock); 886 FOREACH_PROC_IN_SYSTEM(p) { 887 PROC_LOCK(p); 888 if (p->p_tracevp == vp) { 889 if (ktrcanset(td, p)) { 890 mtx_lock(&ktrace_mtx); 891 ktr_freeproc(p, &cred, NULL); 892 mtx_unlock(&ktrace_mtx); 893 vrele_count++; 894 crfree(cred); 895 } else 896 error = EPERM; 897 } 898 PROC_UNLOCK(p); 899 } 900 sx_sunlock(&allproc_lock); 901 if (vrele_count > 0) { 902 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 903 while (vrele_count-- > 0) 904 vrele(vp); 905 VFS_UNLOCK_GIANT(vfslocked); 906 } 907 goto done; 908 } 909 /* 910 * do it 911 */ 912 sx_slock(&proctree_lock); 913 if (uap->pid < 0) { 914 /* 915 * by process group 916 */ 917 pg = pgfind(-uap->pid); 918 if (pg == NULL) { 919 sx_sunlock(&proctree_lock); 920 error = ESRCH; 921 goto done; 922 } 923 /* 924 * ktrops() may call vrele(). Lock pg_members 925 * by the proctree_lock rather than pg_mtx. 926 */ 927 PGRP_UNLOCK(pg); 928 nfound = 0; 929 LIST_FOREACH(p, &pg->pg_members, p_pglist) { 930 PROC_LOCK(p); 931 if (p->p_state == PRS_NEW || 932 p_cansee(td, p) != 0) { 933 PROC_UNLOCK(p); 934 continue; 935 } 936 nfound++; 937 if (descend) 938 ret |= ktrsetchildren(td, p, ops, facs, vp); 939 else 940 ret |= ktrops(td, p, ops, facs, vp); 941 } 942 if (nfound == 0) { 943 sx_sunlock(&proctree_lock); 944 error = ESRCH; 945 goto done; 946 } 947 } else { 948 /* 949 * by pid 950 */ 951 p = pfind(uap->pid); 952 if (p == NULL) 953 error = ESRCH; 954 else 955 error = p_cansee(td, p); 956 if (error) { 957 if (p != NULL) 958 PROC_UNLOCK(p); 959 sx_sunlock(&proctree_lock); 960 goto done; 961 } 962 if (descend) 963 ret |= ktrsetchildren(td, p, ops, facs, vp); 964 else 965 ret |= ktrops(td, p, ops, facs, vp); 966 } 967 sx_sunlock(&proctree_lock); 968 if (!ret) 969 error = EPERM; 970 done: 971 if (vp != NULL) { 972 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 973 (void) vn_close(vp, FWRITE, td->td_ucred, td); 974 VFS_UNLOCK_GIANT(vfslocked); 975 } 976 ktrace_exit(td); 977 return (error); 978 #else /* !KTRACE */ 979 return (ENOSYS); 980 #endif /* KTRACE */ 981 } 982 983 /* ARGSUSED */ 984 int 985 sys_utrace(td, uap) 986 struct thread *td; 987 register struct utrace_args *uap; 988 { 989 990 #ifdef KTRACE 991 struct ktr_request *req; 992 void *cp; 993 int error; 994 995 if (!KTRPOINT(td, KTR_USER)) 996 return (0); 997 if (uap->len > KTR_USER_MAXLEN) 998 return (EINVAL); 999 cp = malloc(uap->len, M_KTRACE, M_WAITOK); 1000 error = copyin(uap->addr, cp, uap->len); 1001 if (error) { 1002 free(cp, M_KTRACE); 1003 return (error); 1004 } 1005 req = ktr_getrequest(KTR_USER); 1006 if (req == NULL) { 1007 free(cp, M_KTRACE); 1008 return (ENOMEM); 1009 } 1010 req->ktr_buffer = cp; 1011 req->ktr_header.ktr_len = uap->len; 1012 ktr_submitrequest(td, req); 1013 return (0); 1014 #else /* !KTRACE */ 1015 return (ENOSYS); 1016 #endif /* KTRACE */ 1017 } 1018 1019 #ifdef KTRACE 1020 static int 1021 ktrops(td, p, ops, facs, vp) 1022 struct thread *td; 1023 struct proc *p; 1024 int ops, facs; 1025 struct vnode *vp; 1026 { 1027 struct vnode *tracevp = NULL; 1028 struct ucred *tracecred = NULL; 1029 1030 PROC_LOCK_ASSERT(p, MA_OWNED); 1031 if (!ktrcanset(td, p)) { 1032 PROC_UNLOCK(p); 1033 return (0); 1034 } 1035 if (p->p_flag & P_WEXIT) { 1036 /* If the process is exiting, just ignore it. */ 1037 PROC_UNLOCK(p); 1038 return (1); 1039 } 1040 mtx_lock(&ktrace_mtx); 1041 if (ops == KTROP_SET) { 1042 if (p->p_tracevp != vp) { 1043 /* 1044 * if trace file already in use, relinquish below 1045 */ 1046 tracevp = p->p_tracevp; 1047 VREF(vp); 1048 p->p_tracevp = vp; 1049 } 1050 if (p->p_tracecred != td->td_ucred) { 1051 tracecred = p->p_tracecred; 1052 p->p_tracecred = crhold(td->td_ucred); 1053 } 1054 p->p_traceflag |= facs; 1055 if (priv_check(td, PRIV_KTRACE) == 0) 1056 p->p_traceflag |= KTRFAC_ROOT; 1057 } else { 1058 /* KTROP_CLEAR */ 1059 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) 1060 /* no more tracing */ 1061 ktr_freeproc(p, &tracecred, &tracevp); 1062 } 1063 mtx_unlock(&ktrace_mtx); 1064 if ((p->p_traceflag & KTRFAC_MASK) != 0) 1065 ktrprocctor_entered(td, p); 1066 PROC_UNLOCK(p); 1067 if (tracevp != NULL) { 1068 int vfslocked; 1069 1070 vfslocked = VFS_LOCK_GIANT(tracevp->v_mount); 1071 vrele(tracevp); 1072 VFS_UNLOCK_GIANT(vfslocked); 1073 } 1074 if (tracecred != NULL) 1075 crfree(tracecred); 1076 1077 return (1); 1078 } 1079 1080 static int 1081 ktrsetchildren(td, top, ops, facs, vp) 1082 struct thread *td; 1083 struct proc *top; 1084 int ops, facs; 1085 struct vnode *vp; 1086 { 1087 register struct proc *p; 1088 register int ret = 0; 1089 1090 p = top; 1091 PROC_LOCK_ASSERT(p, MA_OWNED); 1092 sx_assert(&proctree_lock, SX_LOCKED); 1093 for (;;) { 1094 ret |= ktrops(td, p, ops, facs, vp); 1095 /* 1096 * If this process has children, descend to them next, 1097 * otherwise do any siblings, and if done with this level, 1098 * follow back up the tree (but not past top). 1099 */ 1100 if (!LIST_EMPTY(&p->p_children)) 1101 p = LIST_FIRST(&p->p_children); 1102 else for (;;) { 1103 if (p == top) 1104 return (ret); 1105 if (LIST_NEXT(p, p_sibling)) { 1106 p = LIST_NEXT(p, p_sibling); 1107 break; 1108 } 1109 p = p->p_pptr; 1110 } 1111 PROC_LOCK(p); 1112 } 1113 /*NOTREACHED*/ 1114 } 1115 1116 static void 1117 ktr_writerequest(struct thread *td, struct ktr_request *req) 1118 { 1119 struct ktr_header *kth; 1120 struct vnode *vp; 1121 struct proc *p; 1122 struct ucred *cred; 1123 struct uio auio; 1124 struct iovec aiov[3]; 1125 struct mount *mp; 1126 int datalen, buflen, vrele_count; 1127 int error, vfslocked; 1128 1129 /* 1130 * We hold the vnode and credential for use in I/O in case ktrace is 1131 * disabled on the process as we write out the request. 1132 * 1133 * XXXRW: This is not ideal: we could end up performing a write after 1134 * the vnode has been closed. 1135 */ 1136 mtx_lock(&ktrace_mtx); 1137 vp = td->td_proc->p_tracevp; 1138 cred = td->td_proc->p_tracecred; 1139 1140 /* 1141 * If vp is NULL, the vp has been cleared out from under this 1142 * request, so just drop it. Make sure the credential and vnode are 1143 * in sync: we should have both or neither. 1144 */ 1145 if (vp == NULL) { 1146 KASSERT(cred == NULL, ("ktr_writerequest: cred != NULL")); 1147 mtx_unlock(&ktrace_mtx); 1148 return; 1149 } 1150 VREF(vp); 1151 KASSERT(cred != NULL, ("ktr_writerequest: cred == NULL")); 1152 crhold(cred); 1153 mtx_unlock(&ktrace_mtx); 1154 1155 kth = &req->ktr_header; 1156 KASSERT(((u_short)kth->ktr_type & ~KTR_DROP) < 1157 sizeof(data_lengths) / sizeof(data_lengths[0]), 1158 ("data_lengths array overflow")); 1159 datalen = data_lengths[(u_short)kth->ktr_type & ~KTR_DROP]; 1160 buflen = kth->ktr_len; 1161 auio.uio_iov = &aiov[0]; 1162 auio.uio_offset = 0; 1163 auio.uio_segflg = UIO_SYSSPACE; 1164 auio.uio_rw = UIO_WRITE; 1165 aiov[0].iov_base = (caddr_t)kth; 1166 aiov[0].iov_len = sizeof(struct ktr_header); 1167 auio.uio_resid = sizeof(struct ktr_header); 1168 auio.uio_iovcnt = 1; 1169 auio.uio_td = td; 1170 if (datalen != 0) { 1171 aiov[1].iov_base = (caddr_t)&req->ktr_data; 1172 aiov[1].iov_len = datalen; 1173 auio.uio_resid += datalen; 1174 auio.uio_iovcnt++; 1175 kth->ktr_len += datalen; 1176 } 1177 if (buflen != 0) { 1178 KASSERT(req->ktr_buffer != NULL, ("ktrace: nothing to write")); 1179 aiov[auio.uio_iovcnt].iov_base = req->ktr_buffer; 1180 aiov[auio.uio_iovcnt].iov_len = buflen; 1181 auio.uio_resid += buflen; 1182 auio.uio_iovcnt++; 1183 } 1184 1185 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1186 vn_start_write(vp, &mp, V_WAIT); 1187 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1188 #ifdef MAC 1189 error = mac_vnode_check_write(cred, NOCRED, vp); 1190 if (error == 0) 1191 #endif 1192 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, cred); 1193 VOP_UNLOCK(vp, 0); 1194 vn_finished_write(mp); 1195 crfree(cred); 1196 if (!error) { 1197 vrele(vp); 1198 VFS_UNLOCK_GIANT(vfslocked); 1199 return; 1200 } 1201 VFS_UNLOCK_GIANT(vfslocked); 1202 1203 /* 1204 * If error encountered, give up tracing on this vnode. We defer 1205 * all the vrele()'s on the vnode until after we are finished walking 1206 * the various lists to avoid needlessly holding locks. 1207 * NB: at this point we still hold the vnode reference that must 1208 * not go away as we need the valid vnode to compare with. Thus let 1209 * vrele_count start at 1 and the reference will be freed 1210 * by the loop at the end after our last use of vp. 1211 */ 1212 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 1213 error); 1214 vrele_count = 1; 1215 /* 1216 * First, clear this vnode from being used by any processes in the 1217 * system. 1218 * XXX - If one process gets an EPERM writing to the vnode, should 1219 * we really do this? Other processes might have suitable 1220 * credentials for the operation. 1221 */ 1222 cred = NULL; 1223 sx_slock(&allproc_lock); 1224 FOREACH_PROC_IN_SYSTEM(p) { 1225 PROC_LOCK(p); 1226 if (p->p_tracevp == vp) { 1227 mtx_lock(&ktrace_mtx); 1228 ktr_freeproc(p, &cred, NULL); 1229 mtx_unlock(&ktrace_mtx); 1230 vrele_count++; 1231 } 1232 PROC_UNLOCK(p); 1233 if (cred != NULL) { 1234 crfree(cred); 1235 cred = NULL; 1236 } 1237 } 1238 sx_sunlock(&allproc_lock); 1239 1240 vfslocked = VFS_LOCK_GIANT(vp->v_mount); 1241 while (vrele_count-- > 0) 1242 vrele(vp); 1243 VFS_UNLOCK_GIANT(vfslocked); 1244 } 1245 1246 /* 1247 * Return true if caller has permission to set the ktracing state 1248 * of target. Essentially, the target can't possess any 1249 * more permissions than the caller. KTRFAC_ROOT signifies that 1250 * root previously set the tracing status on the target process, and 1251 * so, only root may further change it. 1252 */ 1253 static int 1254 ktrcanset(td, targetp) 1255 struct thread *td; 1256 struct proc *targetp; 1257 { 1258 1259 PROC_LOCK_ASSERT(targetp, MA_OWNED); 1260 if (targetp->p_traceflag & KTRFAC_ROOT && 1261 priv_check(td, PRIV_KTRACE)) 1262 return (0); 1263 1264 if (p_candebug(td, targetp) != 0) 1265 return (0); 1266 1267 return (1); 1268 } 1269 1270 #endif /* KTRACE */
Cache object: 032abec00efca38fb5f5fbdb63a03672
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