sys/kern/kern_ktrace.c

   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: src/sys/kern/kern_ktrace.c,v 1.35.2.6 2002/07/05 22:36:38 darrenr Exp $
  35  */
  36
  37 #include "opt_ktrace.h"
  38
  39 #include <sys/param.h>
  40 #include <sys/systm.h>
  41 #include <sys/sysproto.h>
  42 #include <sys/kernel.h>
  43 #include <sys/proc.h>
  44 #include <sys/fcntl.h>
  45 #include <sys/lock.h>
  46 #include <sys/nlookup.h>
  47 #include <sys/vnode.h>
  48 #include <sys/ktrace.h>
  49 #include <sys/malloc.h>
  50 #include <sys/syslog.h>
  51 #include <sys/sysent.h>
  52
  53 #include <vm/vm_zone.h>
  54
  55 #include <sys/mplock2.h>
  56
  57 static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
  58
  59 #ifdef KTRACE
  60 static void ktrgetheader (struct ktr_header *kth, int type);
  61 static struct ktr_syscall *ktrgetsyscall(struct ktr_header *kth,
  62                                 struct ktr_syscall *ktp_cache, int narg);
  63 static void ktrputsyscall(struct ktr_syscall *ktp_cache,
  64                                 struct ktr_syscall *ktp);
  65 static void ktrwrite (struct lwp *, struct ktr_header *, struct uio *);
  66 static int ktrcanset (struct thread *,struct proc *);
  67 static int ktrsetchildren (struct thread *, struct proc *,
  68                                 int, int, ktrace_node_t);
  69 static int ktrops (struct thread *,struct proc *,int,int, ktrace_node_t);
  70
  71 /*
  72  * MPSAFE
  73  */
  74 static
  75 void
  76 ktrgetheader(struct ktr_header *kth, int type)
  77 {
  78         thread_t td = curthread;
  79         struct proc *p = td->td_proc;
  80         struct lwp *lp = td->td_lwp;
  81
  82         kth->ktr_type = type;
  83         /* XXX threaded flag is a hack at the moment */
  84         kth->ktr_flags = (p->p_nthreads > 1) ? KTRH_THREADED : 0;
  85         kth->ktr_flags |= KTRH_CPUID_ENCODE(td->td_gd->gd_cpuid);
  86         /*microtime(&kth->ktr_time); set in ktrwrite */
  87         kth->ktr_pid = p->p_pid;
  88         kth->ktr_tid = lp->lwp_tid;
  89         bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
  90 }
  91
  92 static
  93 struct ktr_syscall *
  94 ktrgetsyscall(struct ktr_header *kth, struct ktr_syscall *ktp_cache, int narg)
  95 {
  96         size_t len;
  97
  98         len = offsetof(struct ktr_syscall, ktr_args[narg]);
  99         if (len > sizeof(*ktp_cache))
 100                 ktp_cache = kmalloc(len, M_KTRACE, M_WAITOK);
 101         kth->ktr_buf = (caddr_t)ktp_cache;
 102         kth->ktr_len = (int)len;
 103         return (ktp_cache);
 104 }
 105
 106 static
 107 void
 108 ktrputsyscall(struct ktr_syscall *ktp_cache, struct ktr_syscall *ktp)
 109 {
 110         if (ktp != ktp_cache)
 111                 kfree(ktp, M_KTRACE);
 112 }
 113
 114 void
 115 ktrsyscall(struct lwp *lp, int code, int narg, register_t args[])
 116 {
 117         struct ktr_header kth;
 118         struct ktr_syscall ktp_cache;
 119         struct ktr_syscall *ktp;
 120         register_t *argp;
 121         int i;
 122
 123         /*
 124          * Setting the active bit prevents a ktrace recursion from the
 125          * ktracing op itself.
 126          */
 127         lp->lwp_traceflag |= KTRFAC_ACTIVE;
 128         ktrgetheader(&kth, KTR_SYSCALL);
 129
 130         ktp = ktrgetsyscall(&kth, &ktp_cache, narg);
 131         ktp->ktr_code = code;
 132         ktp->ktr_narg = narg;
 133         argp = &ktp->ktr_args[0];
 134         for (i = 0; i < narg; i++)
 135                 *argp++ = args[i];
 136         ktrwrite(lp, &kth, NULL);
 137
 138         ktrputsyscall(&ktp_cache, ktp);
 139         lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 140 }
 141
 142 void
 143 ktrsysret(struct lwp *lp, int code, int error, register_t retval)
 144 {
 145         struct ktr_header kth;
 146         struct ktr_sysret ktp;
 147
 148         lp->lwp_traceflag |= KTRFAC_ACTIVE;
 149         ktrgetheader(&kth, KTR_SYSRET);
 150
 151         ktp.ktr_code = code;
 152         ktp.ktr_error = error;
 153         if (error == 0)
 154                 ktp.ktr_retval = retval;                /* what about val2 ? */
 155         else
 156                 ktp.ktr_retval = 0;
 157
 158         kth.ktr_buf = (caddr_t)&ktp;
 159         kth.ktr_len = (int)sizeof(struct ktr_sysret);
 160
 161         ktrwrite(lp, &kth, NULL);
 162         lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 163 }
 164
 165 void
 166 ktrnamei(struct lwp *lp, char *path)
 167 {
 168         struct ktr_header kth;
 169
 170         lp->lwp_traceflag |= KTRFAC_ACTIVE;
 171         ktrgetheader(&kth, KTR_NAMEI);
 172
 173         kth.ktr_len = (int)strlen(path);
 174         kth.ktr_buf = path;
 175
 176         ktrwrite(lp, &kth, NULL);
 177         lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 178 }
 179
 180 void
 181 ktrgenio(struct lwp *lp, int fd, enum uio_rw rw, struct uio *uio, int error)
 182 {
 183         struct ktr_header kth;
 184         struct ktr_genio ktg;
 185
 186         if (error)
 187                 return;
 188         lp->lwp_traceflag |= KTRFAC_ACTIVE;
 189         ktrgetheader(&kth, KTR_GENIO);
 190
 191         ktg.ktr_fd = fd;
 192         ktg.ktr_rw = rw;
 193         kth.ktr_buf = (caddr_t)&ktg;
 194         kth.ktr_len = (int)sizeof(struct ktr_genio);
 195         uio->uio_offset = 0;
 196         uio->uio_rw = UIO_WRITE;
 197
 198         ktrwrite(lp, &kth, uio);
 199         lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 200 }
 201
 202 void
 203 ktrpsig(struct lwp *lp, int sig, sig_t action, sigset_t *mask, int code)
 204 {
 205         struct ktr_header kth;
 206         struct ktr_psig kp;
 207
 208         lp->lwp_traceflag |= KTRFAC_ACTIVE;
 209         ktrgetheader(&kth, KTR_PSIG);
 210
 211         kp.signo = (char)sig;
 212         kp.action = action;
 213         kp.mask = *mask;
 214         kp.code = code;
 215         kth.ktr_buf = (caddr_t)&kp;
 216         kth.ktr_len = (int)sizeof(struct ktr_psig);
 217
 218         ktrwrite(lp, &kth, NULL);
 219         lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 220 }
 221
 222 void
 223 ktrcsw(struct lwp *lp, int out, int user)
 224 {
 225         struct ktr_header kth;
 226         struct ktr_csw kc;
 227
 228         lp->lwp_traceflag |= KTRFAC_ACTIVE;
 229         ktrgetheader(&kth, KTR_CSW);
 230
 231         kc.out = out;
 232         kc.user = user;
 233         kth.ktr_buf = (caddr_t)&kc;
 234         kth.ktr_len = (int)sizeof(struct ktr_csw);
 235
 236         ktrwrite(lp, &kth, NULL);
 237         lp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 238 }
 239 #endif
 240
 241 /* Interface and common routines */
 242
 243 #ifdef KTRACE
 244 /*
 245  * ktrace system call
 246  */
 247 struct ktrace_clear_info {
 248         ktrace_node_t tracenode;
 249         int rootclear;
 250         int error;
 251 };
 252
 253 static int ktrace_clear_callback(struct proc *p, void *data);
 254
 255 #endif
 256
 257 /*
 258  * MPALMOSTSAFE
 259  */
 260 int
 261 sys_ktrace(struct ktrace_args *uap)
 262 {
 263 #ifdef KTRACE
 264         struct ktrace_clear_info info;
 265         struct thread *td = curthread;
 266         struct proc *curp = td->td_proc;
 267         struct proc *p;
 268         struct pgrp *pg;
 269         int facs = uap->facs & ~KTRFAC_ROOT;
 270         int ops = KTROP(uap->ops);
 271         int descend = uap->ops & KTRFLAG_DESCEND;
 272         int ret = 0;
 273         int error = 0;
 274         struct nlookupdata nd;
 275         ktrace_node_t tracenode = NULL;
 276
 277         get_mplock();
 278         curp->p_traceflag |= KTRFAC_ACTIVE;
 279         if (ops != KTROP_CLEAR) {
 280                 /*
 281                  * an operation which requires a file argument.
 282                  */
 283                 error = nlookup_init(&nd, uap->fname,
 284                                         UIO_USERSPACE, NLC_LOCKVP);
 285                 if (error == 0)
 286                         error = vn_open(&nd, NULL, FREAD|FWRITE|O_NOFOLLOW, 0);
 287                 if (error == 0 && nd.nl_open_vp->v_type != VREG)
 288                         error = EACCES;
 289                 if (error) {
 290                         curp->p_traceflag &= ~KTRFAC_ACTIVE;
 291                         nlookup_done(&nd);
 292                         goto done;
 293                 }
 294                 tracenode = kmalloc(sizeof(struct ktrace_node), M_KTRACE,
 295                                     M_WAITOK | M_ZERO);
 296                 tracenode->kn_vp = nd.nl_open_vp;
 297                 tracenode->kn_refs = 1;
 298                 nd.nl_open_vp = NULL;
 299                 nlookup_done(&nd);
 300                 vn_unlock(tracenode->kn_vp);
 301         }
 302         /*
 303          * Clear all uses of the tracefile.  Not the most efficient operation
 304          * in the world.
 305          */
 306         if (ops == KTROP_CLEARFILE) {
 307                 info.tracenode = tracenode;
 308                 info.error = 0;
 309                 info.rootclear = 0;
 310                 allproc_scan(ktrace_clear_callback, &info);
 311                 error = info.error;
 312                 goto done;
 313         }
 314         /*
 315          * need something to (un)trace (XXX - why is this here?)
 316          */
 317         if (!facs) {
 318                 error = EINVAL;
 319                 goto done;
 320         }
 321         /*
 322          * do it
 323          */
 324         if (uap->pid < 0) {
 325                 /*
 326                  * By process group.  Process group is referenced, preventing
 327                  * disposal.
 328                  */
 329                 pg = pgfind(-uap->pid);
 330                 if (pg == NULL) {
 331                         error = ESRCH;
 332                         goto done;
 333                 }
 334                 lwkt_gettoken(&pg->pg_token);
 335                 LIST_FOREACH(p, &pg->pg_members, p_pglist) {
 336                         PHOLD(p);
 337                         if (descend)
 338                                 ret |= ktrsetchildren(td, p, ops, facs, tracenode);
 339                         else
 340                                 ret |= ktrops(td, p, ops, facs, tracenode);
 341                         PRELE(p);
 342                 }
 343                 lwkt_reltoken(&pg->pg_token);
 344                 pgrel(pg);
 345         } else {
 346                 /*
 347                  * by pid
 348                  */
 349                 p = pfind(uap->pid);
 350                 if (p == NULL) {
 351                         error = ESRCH;
 352                         goto done;
 353                 }
 354                 if (descend)
 355                         ret |= ktrsetchildren(td, p, ops, facs, tracenode);
 356                 else
 357                         ret |= ktrops(td, p, ops, facs, tracenode);
 358                 PRELE(p);
 359         }
 360         if (!ret)
 361                 error = EPERM;
 362 done:
 363         if (tracenode)
 364                 ktrdestroy(&tracenode);
 365         curp->p_traceflag &= ~KTRFAC_ACTIVE;
 366         rel_mplock();
 367         return (error);
 368 #else
 369         return ENOSYS;
 370 #endif
 371 }
 372
 373 #ifdef KTRACE
 374
 375 /*
 376  * NOTE: NOT MPSAFE (yet)
 377  */
 378 static int
 379 ktrace_clear_callback(struct proc *p, void *data)
 380 {
 381         struct ktrace_clear_info *info = data;
 382
 383         if (p->p_tracenode) {
 384                 if (info->rootclear) {
 385                         if (p->p_tracenode == info->tracenode) {
 386                                 ktrdestroy(&p->p_tracenode);
 387                                 p->p_traceflag = 0;
 388                         }
 389                 } else {
 390                         if (p->p_tracenode->kn_vp == info->tracenode->kn_vp) {
 391                                 if (ktrcanset(curthread, p)) {
 392                                         ktrdestroy(&p->p_tracenode);
 393                                         p->p_traceflag = 0;
 394                                 } else {
 395                                         info->error = EPERM;
 396                                 }
 397                         }
 398                 }
 399         }
 400         return(0);
 401 }
 402
 403 #endif
 404
 405 /*
 406  * utrace system call
 407  *
 408  * MPALMOSTSAFE
 409  */
 410 int
 411 sys_utrace(struct utrace_args *uap)
 412 {
 413 #ifdef KTRACE
 414         struct ktr_header kth;
 415         struct thread *td = curthread;  /* XXX */
 416         char cp_cache[64];
 417         caddr_t cp;
 418
 419         if (!KTRPOINT(td, KTR_USER))
 420                 return (0);
 421         if (uap->len > KTR_USER_MAXLEN)
 422                 return (EINVAL);
 423         td->td_lwp->lwp_traceflag |= KTRFAC_ACTIVE;
 424         ktrgetheader(&kth, KTR_USER);
 425         if (uap->len <= sizeof(cp_cache))
 426                 cp = cp_cache;
 427         else
 428                 cp = kmalloc(uap->len, M_KTRACE, M_WAITOK);
 429
 430         if (!copyin(uap->addr, cp, uap->len)) {
 431                 kth.ktr_buf = cp;
 432                 kth.ktr_len = uap->len;
 433                 ktrwrite(td->td_lwp, &kth, NULL);
 434         }
 435         if (cp != cp_cache)
 436                 kfree(cp, M_KTRACE);
 437         td->td_lwp->lwp_traceflag &= ~KTRFAC_ACTIVE;
 438
 439         return (0);
 440 #else
 441         return (ENOSYS);
 442 #endif
 443 }
 444
 445 void
 446 ktrdestroy(struct ktrace_node **tracenodep)
 447 {
 448         ktrace_node_t tracenode;
 449
 450         if ((tracenode = *tracenodep) != NULL) {
 451                 *tracenodep = NULL;
 452                 KKASSERT(tracenode->kn_refs > 0);
 453                 if (atomic_fetchadd_int(&tracenode->kn_refs, -1) == 1) {
 454                         vn_close(tracenode->kn_vp, FREAD|FWRITE);
 455                         tracenode->kn_vp = NULL;
 456                         kfree(tracenode, M_KTRACE);
 457                 }
 458         }
 459 }
 460
 461 /*
 462  * This allows a process to inherit a ref on a tracenode and is also used
 463  * as a temporary ref to prevent a tracenode from being destroyed out from
 464  * under an active operation.
 465  */
 466 ktrace_node_t
 467 ktrinherit(ktrace_node_t tracenode)
 468 {
 469         if (tracenode) {
 470                 KKASSERT(tracenode->kn_refs > 0);
 471                 atomic_add_int(&tracenode->kn_refs, 1);
 472         }
 473         return(tracenode);
 474 }
 475
 476 #ifdef KTRACE
 477 static int
 478 ktrops(struct thread *td, struct proc *p, int ops, int facs,
 479        ktrace_node_t tracenode)
 480 {
 481         ktrace_node_t oldnode;
 482
 483         if (!ktrcanset(td, p))
 484                 return (0);
 485         if (ops == KTROP_SET) {
 486                 if ((oldnode = p->p_tracenode) != tracenode) {
 487                         p->p_tracenode = ktrinherit(tracenode);
 488                         ktrdestroy(&oldnode);
 489                 }
 490                 p->p_traceflag |= facs;
 491                 if (td->td_ucred->cr_uid == 0)
 492                         p->p_traceflag |= KTRFAC_ROOT;
 493         } else {
 494                 /* KTROP_CLEAR */
 495                 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
 496                         /* no more tracing */
 497                         p->p_traceflag = 0;
 498                         ktrdestroy(&p->p_tracenode);
 499                 }
 500         }
 501
 502         return (1);
 503 }
 504
 505 static int
 506 ktrsetchildren(struct thread *td, struct proc *top, int ops, int facs,
 507                ktrace_node_t tracenode)
 508 {
 509         struct proc *p;
 510         struct proc *np;
 511         int ret = 0;
 512
 513         p = top;
 514         PHOLD(p);
 515         lwkt_gettoken(&p->p_token);
 516
 517         for (;;) {
 518                 ret |= ktrops(td, p, ops, facs, tracenode);
 519
 520                 /*
 521                  * If this process has children, descend to them next,
 522                  * otherwise do any siblings, and if done with this level,
 523                  * follow back up the tree (but not past top).
 524                  */
 525                 if ((np = LIST_FIRST(&p->p_children)) != NULL) {
 526                         PHOLD(np);
 527                 }
 528                 while (np == NULL) {
 529                         if (p == top)
 530                                 break;
 531                         if ((np = LIST_NEXT(p, p_sibling)) != NULL) {
 532                                 PHOLD(np);
 533                                 break;
 534                         }
 535
 536                         /*
 537                          * recurse up to parent, set p in our inner
 538                          * loop when doing this.  np can be NULL if
 539                          * we race a reparenting to init (thus 'top'
 540                          * is skipped past and never encountered).
 541                          */
 542                         np = p->p_pptr;
 543                         if (np == NULL)
 544                                 break;
 545                         PHOLD(np);
 546                         lwkt_reltoken(&p->p_token);
 547                         PRELE(p);
 548                         p = np;
 549                         lwkt_gettoken(&p->p_token);
 550                         np = NULL;
 551                 }
 552                 lwkt_reltoken(&p->p_token);
 553                 PRELE(p);
 554                 p = np;
 555                 if (p == NULL)
 556                         break;
 557                 /* Already held, but we need the token too */
 558                 lwkt_gettoken(&p->p_token);
 559         }
 560         return (ret);
 561 }
 562
 563 static void
 564 ktrwrite(struct lwp *lp, struct ktr_header *kth, struct uio *uio)
 565 {
 566         struct ktrace_clear_info info;
 567         struct uio auio;
 568         struct iovec aiov[2];
 569         int error;
 570         ktrace_node_t tracenode;
 571
 572         /*
 573          * We have to ref our tracenode to prevent it from being ripped out
 574          * from under us while we are trying to use it.   p_tracenode can
 575          * go away at any time if another process gets a write error.
 576          *
 577          * XXX not MP safe
 578          */
 579         if (lp->lwp_proc->p_tracenode == NULL)
 580                 return;
 581         tracenode = ktrinherit(lp->lwp_proc->p_tracenode);
 582         auio.uio_iov = &aiov[0];
 583         auio.uio_offset = 0;
 584         auio.uio_segflg = UIO_SYSSPACE;
 585         auio.uio_rw = UIO_WRITE;
 586         aiov[0].iov_base = (caddr_t)kth;
 587         aiov[0].iov_len = sizeof(struct ktr_header);
 588         auio.uio_resid = sizeof(struct ktr_header);
 589         auio.uio_iovcnt = 1;
 590         auio.uio_td = curthread;
 591         if (kth->ktr_len > 0) {
 592                 auio.uio_iovcnt++;
 593                 aiov[1].iov_base = kth->ktr_buf;
 594                 aiov[1].iov_len = kth->ktr_len;
 595                 auio.uio_resid += kth->ktr_len;
 596                 if (uio != NULL)
 597                         kth->ktr_len += uio->uio_resid;
 598         }
 599
 600         /*
 601          * NOTE: Must set timestamp after obtaining lock to ensure no
 602          *       timestamp reversals in the output file.
 603          */
 604         vn_lock(tracenode->kn_vp, LK_EXCLUSIVE | LK_RETRY);
 605         microtime(&kth->ktr_time);
 606         error = VOP_WRITE(tracenode->kn_vp, &auio,
 607                           IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred);
 608         if (error == 0 && uio != NULL) {
 609                 error = VOP_WRITE(tracenode->kn_vp, uio,
 610                               IO_UNIT | IO_APPEND, lp->lwp_thread->td_ucred);
 611         }
 612         vn_unlock(tracenode->kn_vp);
 613         if (error) {
 614                 /*
 615                  * If an error occured, give up tracing on all processes
 616                  * using this tracenode.  This is not MP safe but is
 617                  * blocking-safe.
 618                  */
 619                 log(LOG_NOTICE,
 620                     "ktrace write failed, errno %d, tracing stopped\n", error);
 621                 info.tracenode = tracenode;
 622                 info.error = 0;
 623                 info.rootclear = 1;
 624                 allproc_scan(ktrace_clear_callback, &info);
 625         }
 626         ktrdestroy(&tracenode);
 627 }
 628
 629 /*
 630  * Return true if caller has permission to set the ktracing state
 631  * of target.  Essentially, the target can't possess any
 632  * more permissions than the caller.  KTRFAC_ROOT signifies that
 633  * root previously set the tracing status on the target process, and
 634  * so, only root may further change it.
 635  *
 636  * TODO: check groups.  use caller effective gid.
 637  */
 638 static int
 639 ktrcanset(struct thread *calltd, struct proc *targetp)
 640 {
 641         struct ucred *caller = calltd->td_ucred;
 642         struct ucred *target = targetp->p_ucred;
 643
 644         if (!PRISON_CHECK(caller, target))
 645                 return (0);
 646         if ((caller->cr_uid == target->cr_ruid &&
 647              target->cr_ruid == target->cr_svuid &&
 648              caller->cr_rgid == target->cr_rgid &&      /* XXX */
 649              target->cr_rgid == target->cr_svgid &&
 650              (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
 651              (targetp->p_flags & P_SUGID) == 0) ||
 652              caller->cr_uid == 0)
 653                 return (1);
 654
 655         return (0);
 656 }
 657
 658 #endif /* KTRACE */