1 /* 2 * Copyright (c) 1989, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. 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 * $FreeBSD$ 35 */ 36 37 #include "opt_ktrace.h" 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/lock.h> 42 #include <sys/mutex.h> 43 #include <sys/sysproto.h> 44 #include <sys/kernel.h> 45 #include <sys/proc.h> 46 #include <sys/fcntl.h> 47 #include <sys/namei.h> 48 #include <sys/vnode.h> 49 #include <sys/ktrace.h> 50 #include <sys/malloc.h> 51 #include <sys/sx.h> 52 #include <sys/syslog.h> 53 #include <sys/jail.h> 54 55 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE"); 56 57 #ifdef KTRACE 58 static struct ktr_header *ktrgetheader(int type); 59 static void ktrwrite(struct vnode *, struct ktr_header *, struct uio *); 60 static int ktrcanset(struct proc *,struct proc *); 61 static int ktrsetchildren(struct proc *,struct proc *,int,int,struct vnode *); 62 static int ktrops(struct proc *,struct proc *,int,int,struct vnode *); 63 64 65 static struct ktr_header * 66 ktrgetheader(type) 67 int type; 68 { 69 register struct ktr_header *kth; 70 struct proc *p = curproc; /* XXX */ 71 72 MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header), 73 M_KTRACE, M_WAITOK); 74 kth->ktr_type = type; 75 microtime(&kth->ktr_time); 76 kth->ktr_pid = p->p_pid; 77 bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1); 78 return (kth); 79 } 80 81 /* 82 * MPSAFE 83 */ 84 void 85 ktrsyscall(vp, code, narg, args) 86 struct vnode *vp; 87 int code, narg; 88 register_t args[]; 89 { 90 struct ktr_header *kth; 91 struct ktr_syscall *ktp; 92 register int len = offsetof(struct ktr_syscall, ktr_args) + 93 (narg * sizeof(register_t)); 94 struct proc *p = curproc; /* XXX */ 95 register_t *argp; 96 int i; 97 98 mtx_lock(&Giant); 99 p->p_traceflag |= KTRFAC_ACTIVE; 100 kth = ktrgetheader(KTR_SYSCALL); 101 MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK); 102 ktp->ktr_code = code; 103 ktp->ktr_narg = narg; 104 argp = &ktp->ktr_args[0]; 105 for (i = 0; i < narg; i++) 106 *argp++ = args[i]; 107 kth->ktr_buffer = (caddr_t)ktp; 108 kth->ktr_len = len; 109 ktrwrite(vp, kth, NULL); 110 FREE(ktp, M_KTRACE); 111 FREE(kth, M_KTRACE); 112 p->p_traceflag &= ~KTRFAC_ACTIVE; 113 mtx_unlock(&Giant); 114 } 115 116 /* 117 * MPSAFE 118 */ 119 void 120 ktrsysret(vp, code, error, retval) 121 struct vnode *vp; 122 int code, error; 123 register_t retval; 124 { 125 struct ktr_header *kth; 126 struct ktr_sysret ktp; 127 struct proc *p = curproc; /* XXX */ 128 129 mtx_lock(&Giant); 130 p->p_traceflag |= KTRFAC_ACTIVE; 131 kth = ktrgetheader(KTR_SYSRET); 132 ktp.ktr_code = code; 133 ktp.ktr_error = error; 134 ktp.ktr_retval = retval; /* what about val2 ? */ 135 136 kth->ktr_buffer = (caddr_t)&ktp; 137 kth->ktr_len = sizeof(struct ktr_sysret); 138 139 ktrwrite(vp, kth, NULL); 140 FREE(kth, M_KTRACE); 141 p->p_traceflag &= ~KTRFAC_ACTIVE; 142 mtx_unlock(&Giant); 143 } 144 145 void 146 ktrnamei(vp, path) 147 struct vnode *vp; 148 char *path; 149 { 150 struct ktr_header *kth; 151 struct proc *p = curproc; /* XXX */ 152 153 /* 154 * don't let p_tracep get ripped out from under us 155 */ 156 if (vp) 157 VREF(vp); 158 p->p_traceflag |= KTRFAC_ACTIVE; 159 kth = ktrgetheader(KTR_NAMEI); 160 kth->ktr_len = strlen(path); 161 kth->ktr_buffer = path; 162 163 ktrwrite(vp, kth, NULL); 164 if (vp) 165 vrele(vp); 166 FREE(kth, M_KTRACE); 167 p->p_traceflag &= ~KTRFAC_ACTIVE; 168 } 169 170 void 171 ktrgenio(vp, fd, rw, uio, error) 172 struct vnode *vp; 173 int fd; 174 enum uio_rw rw; 175 struct uio *uio; 176 int error; 177 { 178 struct ktr_header *kth; 179 struct ktr_genio ktg; 180 struct proc *p = curproc; /* XXX */ 181 182 if (error) 183 return; 184 185 mtx_lock(&Giant); 186 /* 187 * don't let p_tracep get ripped out from under us 188 */ 189 if (vp) 190 VREF(vp); 191 p->p_traceflag |= KTRFAC_ACTIVE; 192 kth = ktrgetheader(KTR_GENIO); 193 ktg.ktr_fd = fd; 194 ktg.ktr_rw = rw; 195 kth->ktr_buffer = (caddr_t)&ktg; 196 kth->ktr_len = sizeof(struct ktr_genio); 197 uio->uio_offset = 0; 198 uio->uio_rw = UIO_WRITE; 199 200 ktrwrite(vp, kth, uio); 201 if (vp) 202 vrele(vp); 203 FREE(kth, M_KTRACE); 204 p->p_traceflag &= ~KTRFAC_ACTIVE; 205 mtx_unlock(&Giant); 206 } 207 208 void 209 ktrpsig(vp, sig, action, mask, code) 210 struct vnode *vp; 211 int sig; 212 sig_t action; 213 sigset_t *mask; 214 int code; 215 { 216 struct ktr_header *kth; 217 struct ktr_psig kp; 218 struct proc *p = curproc; /* XXX */ 219 220 /* 221 * don't let vp get ripped out from under us 222 */ 223 if (vp) 224 VREF(vp); 225 p->p_traceflag |= KTRFAC_ACTIVE; 226 kth = ktrgetheader(KTR_PSIG); 227 kp.signo = (char)sig; 228 kp.action = action; 229 kp.mask = *mask; 230 kp.code = code; 231 kth->ktr_buffer = (caddr_t)&kp; 232 kth->ktr_len = sizeof (struct ktr_psig); 233 234 ktrwrite(vp, kth, NULL); 235 if (vp) 236 vrele(vp); 237 FREE(kth, M_KTRACE); 238 p->p_traceflag &= ~KTRFAC_ACTIVE; 239 } 240 241 void 242 ktrcsw(vp, out, user) 243 struct vnode *vp; 244 int out, user; 245 { 246 struct ktr_header *kth; 247 struct ktr_csw kc; 248 struct proc *p = curproc; /* XXX */ 249 250 /* 251 * don't let vp get ripped out from under us 252 */ 253 if (vp) 254 VREF(vp); 255 p->p_traceflag |= KTRFAC_ACTIVE; 256 kth = ktrgetheader(KTR_CSW); 257 kc.out = out; 258 kc.user = user; 259 kth->ktr_buffer = (caddr_t)&kc; 260 kth->ktr_len = sizeof (struct ktr_csw); 261 262 ktrwrite(vp, kth, NULL); 263 if (vp) 264 vrele(vp); 265 FREE(kth, M_KTRACE); 266 p->p_traceflag &= ~KTRFAC_ACTIVE; 267 } 268 #endif 269 270 /* Interface and common routines */ 271 272 /* 273 * ktrace system call 274 */ 275 #ifndef _SYS_SYSPROTO_H_ 276 struct ktrace_args { 277 char *fname; 278 int ops; 279 int facs; 280 int pid; 281 }; 282 #endif 283 /* ARGSUSED */ 284 int 285 ktrace(td, uap) 286 struct thread *td; 287 register struct ktrace_args *uap; 288 { 289 #ifdef KTRACE 290 struct proc *curp = td->td_proc; 291 register struct vnode *vp = NULL; 292 register struct proc *p; 293 struct pgrp *pg; 294 int facs = uap->facs & ~KTRFAC_ROOT; 295 int ops = KTROP(uap->ops); 296 int descend = uap->ops & KTRFLAG_DESCEND; 297 int ret = 0; 298 int flags, error = 0; 299 struct nameidata nd; 300 301 curp->p_traceflag |= KTRFAC_ACTIVE; 302 if (ops != KTROP_CLEAR) { 303 /* 304 * an operation which requires a file argument. 305 */ 306 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, td); 307 flags = FREAD | FWRITE | O_NOFOLLOW; 308 error = vn_open(&nd, &flags, 0); 309 if (error) { 310 curp->p_traceflag &= ~KTRFAC_ACTIVE; 311 return (error); 312 } 313 NDFREE(&nd, NDF_ONLY_PNBUF); 314 vp = nd.ni_vp; 315 VOP_UNLOCK(vp, 0, td); 316 if (vp->v_type != VREG) { 317 (void) vn_close(vp, FREAD|FWRITE, td->td_ucred, td); 318 curp->p_traceflag &= ~KTRFAC_ACTIVE; 319 return (EACCES); 320 } 321 } 322 /* 323 * Clear all uses of the tracefile. 324 */ 325 if (ops == KTROP_CLEARFILE) { 326 sx_slock(&allproc_lock); 327 LIST_FOREACH(p, &allproc, p_list) { 328 if (p->p_tracep == vp) { 329 if (ktrcanset(curp, p) && p->p_tracep == vp) { 330 p->p_tracep = NULL; 331 p->p_traceflag = 0; 332 (void) vn_close(vp, FREAD|FWRITE, 333 td->td_ucred, td); 334 } else { 335 error = EPERM; 336 } 337 } 338 } 339 sx_sunlock(&allproc_lock); 340 goto done; 341 } 342 /* 343 * need something to (un)trace (XXX - why is this here?) 344 */ 345 if (!facs) { 346 error = EINVAL; 347 goto done; 348 } 349 /* 350 * do it 351 */ 352 if (uap->pid < 0) { 353 /* 354 * by process group 355 */ 356 PGRPSESS_SLOCK(); 357 pg = pgfind(-uap->pid); 358 if (pg == NULL) { 359 PGRPSESS_SUNLOCK(); 360 error = ESRCH; 361 goto done; 362 } 363 /* 364 * ktrops() may call vrele(). Lock pg_members 365 * by the pgrpsess_lock rather than pg_mtx. 366 */ 367 PGRP_UNLOCK(pg); 368 LIST_FOREACH(p, &pg->pg_members, p_pglist) 369 if (descend) 370 ret |= ktrsetchildren(curp, p, ops, facs, vp); 371 else 372 ret |= ktrops(curp, p, ops, facs, vp); 373 PGRPSESS_SUNLOCK(); 374 } else { 375 /* 376 * by pid 377 */ 378 p = pfind(uap->pid); 379 if (p == NULL) { 380 error = ESRCH; 381 goto done; 382 } 383 PROC_UNLOCK(p); 384 if (descend) 385 ret |= ktrsetchildren(curp, p, ops, facs, vp); 386 else 387 ret |= ktrops(curp, p, ops, facs, vp); 388 } 389 if (!ret) 390 error = EPERM; 391 done: 392 if (vp != NULL) 393 (void) vn_close(vp, FWRITE, td->td_ucred, td); 394 curp->p_traceflag &= ~KTRFAC_ACTIVE; 395 return (error); 396 #else 397 return ENOSYS; 398 #endif 399 } 400 401 /* 402 * utrace system call 403 */ 404 /* ARGSUSED */ 405 int 406 utrace(td, uap) 407 struct thread *td; 408 register struct utrace_args *uap; 409 { 410 411 #ifdef KTRACE 412 struct ktr_header *kth; 413 struct proc *p = curproc; /* XXX */ 414 struct vnode *vp; 415 register caddr_t cp; 416 417 if (!KTRPOINT(p, KTR_USER)) 418 return (0); 419 if (uap->len > KTR_USER_MAXLEN) 420 return (EINVAL); 421 p->p_traceflag |= KTRFAC_ACTIVE; 422 if ((vp = p->p_tracep) != NULL) 423 VREF(vp); 424 kth = ktrgetheader(KTR_USER); 425 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 426 if (!copyin(uap->addr, cp, uap->len)) { 427 kth->ktr_buffer = cp; 428 kth->ktr_len = uap->len; 429 ktrwrite(vp, kth, NULL); 430 } 431 if (vp) 432 vrele(vp); 433 FREE(kth, M_KTRACE); 434 FREE(cp, M_KTRACE); 435 p->p_traceflag &= ~KTRFAC_ACTIVE; 436 437 return (0); 438 #else 439 return (ENOSYS); 440 #endif 441 } 442 443 #ifdef KTRACE 444 static int 445 ktrops(curp, p, ops, facs, vp) 446 struct proc *p, *curp; 447 int ops, facs; 448 struct vnode *vp; 449 { 450 451 if (!ktrcanset(curp, p)) 452 return (0); 453 if (ops == KTROP_SET) { 454 if (p->p_tracep != vp) { 455 struct vnode *vtmp; 456 457 /* 458 * if trace file already in use, relinquish 459 */ 460 VREF(vp); 461 while ((vtmp = p->p_tracep) != NULL) { 462 p->p_tracep = NULL; 463 vrele(vtmp); 464 } 465 p->p_tracep = vp; 466 } 467 p->p_traceflag |= facs; 468 /* XXX: Not safe */ 469 if (curp->p_ucred->cr_uid == 0) 470 p->p_traceflag |= KTRFAC_ROOT; 471 } else { 472 /* KTROP_CLEAR */ 473 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) { 474 struct vnode *vtmp; 475 476 /* no more tracing */ 477 p->p_traceflag = 0; 478 if ((vtmp = p->p_tracep) != NULL) { 479 p->p_tracep = NULL; 480 vrele(vtmp); 481 } 482 } 483 } 484 485 return (1); 486 } 487 488 static int 489 ktrsetchildren(curp, top, ops, facs, vp) 490 struct proc *curp, *top; 491 int ops, facs; 492 struct vnode *vp; 493 { 494 register struct proc *p; 495 register int ret = 0; 496 497 p = top; 498 sx_slock(&proctree_lock); 499 for (;;) { 500 ret |= ktrops(curp, p, ops, facs, vp); 501 /* 502 * If this process has children, descend to them next, 503 * otherwise do any siblings, and if done with this level, 504 * follow back up the tree (but not past top). 505 */ 506 if (!LIST_EMPTY(&p->p_children)) 507 p = LIST_FIRST(&p->p_children); 508 else for (;;) { 509 if (p == top) { 510 sx_sunlock(&proctree_lock); 511 return (ret); 512 } 513 if (LIST_NEXT(p, p_sibling)) { 514 p = LIST_NEXT(p, p_sibling); 515 break; 516 } 517 p = p->p_pptr; 518 } 519 } 520 /*NOTREACHED*/ 521 } 522 523 static void 524 ktrwrite(vp, kth, uio) 525 struct vnode *vp; 526 register struct ktr_header *kth; 527 struct uio *uio; 528 { 529 struct uio auio; 530 struct iovec aiov[2]; 531 struct thread *td = curthread; /* XXX */ 532 struct proc *p = td->td_proc; /* XXX */ 533 struct mount *mp; 534 int error; 535 536 if (vp == NULL) 537 return; 538 auio.uio_iov = &aiov[0]; 539 auio.uio_offset = 0; 540 auio.uio_segflg = UIO_SYSSPACE; 541 auio.uio_rw = UIO_WRITE; 542 aiov[0].iov_base = (caddr_t)kth; 543 aiov[0].iov_len = sizeof(struct ktr_header); 544 auio.uio_resid = sizeof(struct ktr_header); 545 auio.uio_iovcnt = 1; 546 auio.uio_td = curthread; 547 if (kth->ktr_len > 0) { 548 auio.uio_iovcnt++; 549 aiov[1].iov_base = kth->ktr_buffer; 550 aiov[1].iov_len = kth->ktr_len; 551 auio.uio_resid += kth->ktr_len; 552 if (uio != NULL) 553 kth->ktr_len += uio->uio_resid; 554 } 555 vn_start_write(vp, &mp, V_WAIT); 556 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); 557 (void)VOP_LEASE(vp, td, td->td_ucred, LEASE_WRITE); 558 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, td->td_ucred); 559 if (error == 0 && uio != NULL) { 560 (void)VOP_LEASE(vp, td, td->td_ucred, LEASE_WRITE); 561 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, td->td_ucred); 562 } 563 VOP_UNLOCK(vp, 0, td); 564 vn_finished_write(mp); 565 if (!error) 566 return; 567 /* 568 * If error encountered, give up tracing on this vnode. XXX what 569 * happens to the loop if vrele() blocks? 570 */ 571 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 572 error); 573 sx_slock(&allproc_lock); 574 LIST_FOREACH(p, &allproc, p_list) { 575 if (p->p_tracep == vp) { 576 p->p_tracep = NULL; 577 p->p_traceflag = 0; 578 vrele(vp); 579 } 580 } 581 sx_sunlock(&allproc_lock); 582 } 583 584 /* 585 * Return true if caller has permission to set the ktracing state 586 * of target. Essentially, the target can't possess any 587 * more permissions than the caller. KTRFAC_ROOT signifies that 588 * root previously set the tracing status on the target process, and 589 * so, only root may further change it. 590 */ 591 static int 592 ktrcanset(callp, targetp) 593 struct proc *callp, *targetp; 594 { 595 596 if (targetp->p_traceflag & KTRFAC_ROOT && 597 suser_xxx(NULL, callp, PRISON_ROOT)) 598 return (0); 599 600 if (p_candebug(callp, targetp) != 0) 601 return (0); 602 603 return (1); 604 } 605 606 #endif /* KTRACE */ 607