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 __P((int type)); 59 static void ktrwrite __P((struct vnode *, struct ktr_header *, struct uio *)); 60 static int ktrcanset __P((struct proc *,struct proc *)); 61 static int ktrsetchildren __P((struct proc *,struct proc *,int,int,struct vnode *)); 62 static int ktrops __P((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 p->p_traceflag |= KTRFAC_ACTIVE; 154 kth = ktrgetheader(KTR_NAMEI); 155 kth->ktr_len = strlen(path); 156 kth->ktr_buffer = path; 157 158 ktrwrite(vp, kth, NULL); 159 FREE(kth, M_KTRACE); 160 p->p_traceflag &= ~KTRFAC_ACTIVE; 161 } 162 163 void 164 ktrgenio(vp, fd, rw, uio, error) 165 struct vnode *vp; 166 int fd; 167 enum uio_rw rw; 168 struct uio *uio; 169 int error; 170 { 171 struct ktr_header *kth; 172 struct ktr_genio ktg; 173 struct proc *p = curproc; /* XXX */ 174 175 if (error) 176 return; 177 p->p_traceflag |= KTRFAC_ACTIVE; 178 kth = ktrgetheader(KTR_GENIO); 179 ktg.ktr_fd = fd; 180 ktg.ktr_rw = rw; 181 kth->ktr_buffer = (caddr_t)&ktg; 182 kth->ktr_len = sizeof(struct ktr_genio); 183 uio->uio_offset = 0; 184 uio->uio_rw = UIO_WRITE; 185 186 ktrwrite(vp, kth, uio); 187 FREE(kth, M_KTRACE); 188 p->p_traceflag &= ~KTRFAC_ACTIVE; 189 } 190 191 void 192 ktrpsig(vp, sig, action, mask, code) 193 struct vnode *vp; 194 int sig; 195 sig_t action; 196 sigset_t *mask; 197 int code; 198 { 199 struct ktr_header *kth; 200 struct ktr_psig kp; 201 struct proc *p = curproc; /* XXX */ 202 203 p->p_traceflag |= KTRFAC_ACTIVE; 204 kth = ktrgetheader(KTR_PSIG); 205 kp.signo = (char)sig; 206 kp.action = action; 207 kp.mask = *mask; 208 kp.code = code; 209 kth->ktr_buffer = (caddr_t)&kp; 210 kth->ktr_len = sizeof (struct ktr_psig); 211 212 ktrwrite(vp, kth, NULL); 213 FREE(kth, M_KTRACE); 214 p->p_traceflag &= ~KTRFAC_ACTIVE; 215 } 216 217 void 218 ktrcsw(vp, out, user) 219 struct vnode *vp; 220 int out, user; 221 { 222 struct ktr_header *kth; 223 struct ktr_csw kc; 224 struct proc *p = curproc; /* XXX */ 225 226 p->p_traceflag |= KTRFAC_ACTIVE; 227 kth = ktrgetheader(KTR_CSW); 228 kc.out = out; 229 kc.user = user; 230 kth->ktr_buffer = (caddr_t)&kc; 231 kth->ktr_len = sizeof (struct ktr_csw); 232 233 ktrwrite(vp, kth, NULL); 234 FREE(kth, M_KTRACE); 235 p->p_traceflag &= ~KTRFAC_ACTIVE; 236 } 237 #endif 238 239 /* Interface and common routines */ 240 241 /* 242 * ktrace system call 243 */ 244 #ifndef _SYS_SYSPROTO_H_ 245 struct ktrace_args { 246 char *fname; 247 int ops; 248 int facs; 249 int pid; 250 }; 251 #endif 252 /* ARGSUSED */ 253 int 254 ktrace(curp, uap) 255 struct proc *curp; 256 register struct ktrace_args *uap; 257 { 258 #ifdef KTRACE 259 register struct vnode *vp = NULL; 260 register struct proc *p; 261 struct pgrp *pg; 262 int facs = uap->facs & ~KTRFAC_ROOT; 263 int ops = KTROP(uap->ops); 264 int descend = uap->ops & KTRFLAG_DESCEND; 265 int ret = 0; 266 int flags, error = 0; 267 struct nameidata nd; 268 269 curp->p_traceflag |= KTRFAC_ACTIVE; 270 if (ops != KTROP_CLEAR) { 271 /* 272 * an operation which requires a file argument. 273 */ 274 NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_USERSPACE, uap->fname, curp); 275 flags = FREAD | FWRITE | O_NOFOLLOW; 276 error = vn_open(&nd, &flags, 0); 277 if (error) { 278 curp->p_traceflag &= ~KTRFAC_ACTIVE; 279 return (error); 280 } 281 NDFREE(&nd, NDF_ONLY_PNBUF); 282 vp = nd.ni_vp; 283 VOP_UNLOCK(vp, 0, curp); 284 if (vp->v_type != VREG) { 285 (void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp); 286 curp->p_traceflag &= ~KTRFAC_ACTIVE; 287 return (EACCES); 288 } 289 } 290 /* 291 * Clear all uses of the tracefile 292 */ 293 if (ops == KTROP_CLEARFILE) { 294 sx_slock(&allproc_lock); 295 LIST_FOREACH(p, &allproc, p_list) { 296 if (p->p_tracep == vp) { 297 if (ktrcanset(curp, p)) { 298 p->p_tracep = NULL; 299 p->p_traceflag = 0; 300 (void) vn_close(vp, FREAD|FWRITE, 301 p->p_ucred, p); 302 } else 303 error = EPERM; 304 } 305 } 306 sx_sunlock(&allproc_lock); 307 goto done; 308 } 309 /* 310 * need something to (un)trace (XXX - why is this here?) 311 */ 312 if (!facs) { 313 error = EINVAL; 314 goto done; 315 } 316 /* 317 * do it 318 */ 319 if (uap->pid < 0) { 320 /* 321 * by process group 322 */ 323 pg = pgfind(-uap->pid); 324 if (pg == NULL) { 325 error = ESRCH; 326 goto done; 327 } 328 LIST_FOREACH(p, &pg->pg_members, p_pglist) 329 if (descend) 330 ret |= ktrsetchildren(curp, p, ops, facs, vp); 331 else 332 ret |= ktrops(curp, p, ops, facs, vp); 333 } else { 334 /* 335 * by pid 336 */ 337 p = pfind(uap->pid); 338 if (p == NULL) { 339 error = ESRCH; 340 goto done; 341 } 342 PROC_UNLOCK(p); 343 if (descend) 344 ret |= ktrsetchildren(curp, p, ops, facs, vp); 345 else 346 ret |= ktrops(curp, p, ops, facs, vp); 347 } 348 if (!ret) 349 error = EPERM; 350 done: 351 if (vp != NULL) 352 (void) vn_close(vp, FWRITE, curp->p_ucred, curp); 353 curp->p_traceflag &= ~KTRFAC_ACTIVE; 354 return (error); 355 #else 356 return ENOSYS; 357 #endif 358 } 359 360 /* 361 * utrace system call 362 */ 363 /* ARGSUSED */ 364 int 365 utrace(curp, uap) 366 struct proc *curp; 367 register struct utrace_args *uap; 368 { 369 #ifdef KTRACE 370 struct ktr_header *kth; 371 struct proc *p = curproc; /* XXX */ 372 register caddr_t cp; 373 374 if (!KTRPOINT(p, KTR_USER)) 375 return (0); 376 if (uap->len > KTR_USER_MAXLEN) 377 return (EINVAL); 378 p->p_traceflag |= KTRFAC_ACTIVE; 379 kth = ktrgetheader(KTR_USER); 380 MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK); 381 if (!copyin(uap->addr, cp, uap->len)) { 382 kth->ktr_buffer = cp; 383 kth->ktr_len = uap->len; 384 ktrwrite(p->p_tracep, kth, NULL); 385 } 386 FREE(kth, M_KTRACE); 387 FREE(cp, M_KTRACE); 388 p->p_traceflag &= ~KTRFAC_ACTIVE; 389 390 return (0); 391 #else 392 return (ENOSYS); 393 #endif 394 } 395 396 #ifdef KTRACE 397 static int 398 ktrops(curp, p, ops, facs, vp) 399 struct proc *p, *curp; 400 int ops, facs; 401 struct vnode *vp; 402 { 403 404 if (!ktrcanset(curp, p)) 405 return (0); 406 if (ops == KTROP_SET) { 407 if (p->p_tracep != vp) { 408 /* 409 * if trace file already in use, relinquish 410 */ 411 if (p->p_tracep != NULL) 412 vrele(p->p_tracep); 413 VREF(vp); 414 p->p_tracep = vp; 415 } 416 p->p_traceflag |= facs; 417 if (curp->p_ucred->cr_uid == 0) 418 p->p_traceflag |= KTRFAC_ROOT; 419 } else { 420 /* KTROP_CLEAR */ 421 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) { 422 /* no more tracing */ 423 p->p_traceflag = 0; 424 if (p->p_tracep != NULL) { 425 vrele(p->p_tracep); 426 p->p_tracep = NULL; 427 } 428 } 429 } 430 431 return (1); 432 } 433 434 static int 435 ktrsetchildren(curp, top, ops, facs, vp) 436 struct proc *curp, *top; 437 int ops, facs; 438 struct vnode *vp; 439 { 440 register struct proc *p; 441 register int ret = 0; 442 443 p = top; 444 sx_slock(&proctree_lock); 445 for (;;) { 446 ret |= ktrops(curp, p, ops, facs, vp); 447 /* 448 * If this process has children, descend to them next, 449 * otherwise do any siblings, and if done with this level, 450 * follow back up the tree (but not past top). 451 */ 452 if (!LIST_EMPTY(&p->p_children)) 453 p = LIST_FIRST(&p->p_children); 454 else for (;;) { 455 if (p == top) { 456 sx_sunlock(&proctree_lock); 457 return (ret); 458 } 459 if (LIST_NEXT(p, p_sibling)) { 460 p = LIST_NEXT(p, p_sibling); 461 break; 462 } 463 p = p->p_pptr; 464 } 465 } 466 /*NOTREACHED*/ 467 } 468 469 static void 470 ktrwrite(vp, kth, uio) 471 struct vnode *vp; 472 register struct ktr_header *kth; 473 struct uio *uio; 474 { 475 struct uio auio; 476 struct iovec aiov[2]; 477 struct proc *p = curproc; /* XXX */ 478 struct mount *mp; 479 int error; 480 481 if (vp == NULL) 482 return; 483 auio.uio_iov = &aiov[0]; 484 auio.uio_offset = 0; 485 auio.uio_segflg = UIO_SYSSPACE; 486 auio.uio_rw = UIO_WRITE; 487 aiov[0].iov_base = (caddr_t)kth; 488 aiov[0].iov_len = sizeof(struct ktr_header); 489 auio.uio_resid = sizeof(struct ktr_header); 490 auio.uio_iovcnt = 1; 491 auio.uio_procp = curproc; 492 if (kth->ktr_len > 0) { 493 auio.uio_iovcnt++; 494 aiov[1].iov_base = kth->ktr_buffer; 495 aiov[1].iov_len = kth->ktr_len; 496 auio.uio_resid += kth->ktr_len; 497 if (uio != NULL) 498 kth->ktr_len += uio->uio_resid; 499 } 500 vn_start_write(vp, &mp, V_WAIT); 501 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p); 502 (void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 503 error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred); 504 if (error == 0 && uio != NULL) { 505 (void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE); 506 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred); 507 } 508 VOP_UNLOCK(vp, 0, p); 509 vn_finished_write(mp); 510 if (!error) 511 return; 512 /* 513 * If error encountered, give up tracing on this vnode. 514 */ 515 log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n", 516 error); 517 sx_slock(&allproc_lock); 518 LIST_FOREACH(p, &allproc, p_list) { 519 if (p->p_tracep == vp) { 520 p->p_tracep = NULL; 521 p->p_traceflag = 0; 522 vrele(vp); 523 } 524 } 525 sx_sunlock(&allproc_lock); 526 } 527 528 /* 529 * Return true if caller has permission to set the ktracing state 530 * of target. Essentially, the target can't possess any 531 * more permissions than the caller. KTRFAC_ROOT signifies that 532 * root previously set the tracing status on the target process, and 533 * so, only root may further change it. 534 */ 535 static int 536 ktrcanset(callp, targetp) 537 struct proc *callp, *targetp; 538 { 539 540 if (targetp->p_traceflag & KTRFAC_ROOT && 541 suser_xxx(NULL, callp, PRISON_ROOT)) 542 return (0); 543 544 if (p_candebug(callp, targetp) != 0) 545 return (0); 546 547 return (1); 548 } 549 550 #endif /* KTRACE */ 551