bsd/kern/kern_ktrace.c

   1 /*
   2  * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
  23 /*
  24  * Copyright (c) 1989, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the above copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. All advertising materials mentioning features or use of this software
  36  *    must display the following acknowledgement:
  37  *      This product includes software developed by the University of
  38  *      California, Berkeley and its contributors.
  39  * 4. Neither the name of the University nor the names of its contributors
  40  *    may be used to endorse or promote products derived from this software
  41  *    without specific prior written permission.
  42  *
  43  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  44  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  45  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  46  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  47  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  48  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  49  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  50  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  51  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  52  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  53  * SUCH DAMAGE.
  54  *
  55  *      @(#)kern_ktrace.c       8.2 (Berkeley) 9/23/93
  56  * $FreeBSD: src/sys/kern/kern_ktrace.c,v 1.35.2.4 2001/03/05 13:09:01 obrien Exp $
  57  */
  58
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/types.h>
  63 #include <sys/proc.h>
  64 #include <sys/file.h>
  65 #include <sys/namei.h>
  66 #include <sys/vnode.h>
  67 #if KTRACE
  68 #include <sys/ktrace.h>
  69 #endif
  70 #include <sys/malloc.h>
  71 #include <sys/syslog.h>
  72 #include <sys/ubc.h>
  73
  74 #include <bsm/audit_kernel.h>
  75
  76 #if KTRACE
  77 static struct ktr_header *ktrgetheader __P((int type));
  78 static void ktrwrite __P((struct vnode *, struct ktr_header *,
  79         struct uio *, int));
  80 static int ktrcanset __P((struct proc *,struct proc *));
  81 static int ktrsetchildren __P((struct proc *,struct proc *,
  82         int, int, struct vnode *));
  83 static int ktrops __P((struct proc *,struct proc *,int,int,struct vnode *));
  84
  85
  86 static struct ktr_header *
  87 ktrgetheader(type)
  88         int type;
  89 {
  90         register struct ktr_header *kth;
  91         struct proc *p = current_proc();        /* XXX */
  92
  93         MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
  94                 M_KTRACE, M_WAITOK);
  95         kth->ktr_type = type;
  96         microtime(&kth->ktr_time);
  97         kth->ktr_pid = p->p_pid;
  98         bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN);
  99         return (kth);
 100 }
 101 #endif
 102
 103 void
 104 ktrsyscall(p, code, narg, args, funnel_type)
 105         struct proc *p;
 106         int code, narg;
 107         register_t args[];
 108         int funnel_type;
 109 {
 110 #if KTRACE
 111         struct vnode *vp;
 112         struct  ktr_header *kth;
 113         struct  ktr_syscall *ktp;
 114         register int len;
 115         register_t *argp;
 116         int i;
 117
 118         if (!KTRPOINT(p, KTR_SYSCALL))
 119                 return;
 120
 121         vp = p->p_tracep;
 122         len = __offsetof(struct ktr_syscall, ktr_args) +
 123             (narg * sizeof(register_t));
 124         p->p_traceflag |= KTRFAC_ACTIVE;
 125         kth = ktrgetheader(KTR_SYSCALL);
 126         MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
 127         ktp->ktr_code = code;
 128         ktp->ktr_narg = narg;
 129         argp = &ktp->ktr_args[0];
 130         for (i = 0; i < narg; i++)
 131                 *argp++ = args[i];
 132         kth->ktr_buf = (caddr_t)ktp;
 133         kth->ktr_len = len;
 134         ktrwrite(vp, kth, NULL, funnel_type);
 135         FREE(ktp, M_KTRACE);
 136         FREE(kth, M_KTRACE);
 137         p->p_traceflag &= ~KTRFAC_ACTIVE;
 138 #else
 139         return;
 140 #endif
 141 }
 142
 143 void
 144 ktrsysret(p, code, error, retval, funnel_type)
 145         struct proc *p;
 146         int code, error;
 147         register_t retval;
 148         int funnel_type;
 149 {
 150 #if KTRACE
 151         struct vnode *vp;
 152         struct ktr_header *kth;
 153         struct ktr_sysret ktp;
 154
 155         if (!KTRPOINT(p, KTR_SYSRET))
 156                 return;
 157
 158         vp = p->p_tracep;
 159         p->p_traceflag |= KTRFAC_ACTIVE;
 160         kth = ktrgetheader(KTR_SYSRET);
 161         ktp.ktr_code = code;
 162         ktp.ktr_error = error;
 163         ktp.ktr_retval = retval;                /* what about val2 ? */
 164
 165         kth->ktr_buf = (caddr_t)&ktp;
 166         kth->ktr_len = sizeof(struct ktr_sysret);
 167
 168         ktrwrite(vp, kth, NULL, funnel_type);
 169         FREE(kth, M_KTRACE);
 170         p->p_traceflag &= ~KTRFAC_ACTIVE;
 171 #else
 172         return;
 173 #endif
 174 }
 175
 176 #if KTRACE
 177 void
 178 ktrnamei(vp, path)
 179         struct vnode *vp;
 180         char *path;
 181 {
 182         struct ktr_header *kth;
 183         struct proc *p = current_proc();        /* XXX */
 184
 185         p->p_traceflag |= KTRFAC_ACTIVE;
 186         kth = ktrgetheader(KTR_NAMEI);
 187         kth->ktr_len = strlen(path);
 188         kth->ktr_buf = path;
 189
 190         ktrwrite(vp, kth, NULL, KERNEL_FUNNEL);
 191         FREE(kth, M_KTRACE);
 192         p->p_traceflag &= ~KTRFAC_ACTIVE;
 193 }
 194
 195 void
 196 ktrgenio(vp, fd, rw, uio, error, funnel_type)
 197         struct vnode *vp;
 198         int fd;
 199         enum uio_rw rw;
 200         struct uio *uio;
 201         int error;
 202         int funnel_type;
 203 {
 204         struct ktr_header *kth;
 205         struct ktr_genio ktg;
 206         struct proc *p = current_proc();        /* XXX */
 207
 208         if (error)
 209                 return;
 210
 211         p->p_traceflag |= KTRFAC_ACTIVE;
 212         kth = ktrgetheader(KTR_GENIO);
 213         ktg.ktr_fd = fd;
 214         ktg.ktr_rw = rw;
 215         kth->ktr_buf = (caddr_t)&ktg;
 216         kth->ktr_len = sizeof(struct ktr_genio);
 217         uio->uio_offset = 0;
 218         uio->uio_rw = UIO_WRITE;
 219
 220         ktrwrite(vp, kth, uio, funnel_type);
 221         FREE(kth, M_KTRACE);
 222         p->p_traceflag &= ~KTRFAC_ACTIVE;
 223 }
 224
 225 void
 226 ktrpsig(vp, sig, action, mask, code, funnel_type)
 227         struct vnode *vp;
 228         int sig;
 229         sig_t action;
 230         sigset_t *mask;
 231         int code;
 232         int funnel_type;
 233 {
 234         struct ktr_header *kth;
 235         struct ktr_psig kp;
 236         struct proc *p = current_proc();        /* XXX */
 237
 238         p->p_traceflag |= KTRFAC_ACTIVE;
 239         kth = ktrgetheader(KTR_PSIG);
 240         kp.signo = (char)sig;
 241         kp.action = action;
 242         kp.mask = *mask;
 243         kp.code = code;
 244         kth->ktr_buf = (caddr_t)&kp;
 245         kth->ktr_len = sizeof (struct ktr_psig);
 246
 247         ktrwrite(vp, kth, NULL, funnel_type);
 248         FREE(kth, M_KTRACE);
 249         p->p_traceflag &= ~KTRFAC_ACTIVE;
 250 }
 251
 252 void
 253 ktrcsw(vp, out, user, funnel_type)
 254         struct vnode *vp;
 255         int out, user;
 256         int funnel_type;
 257 {
 258         struct ktr_header *kth;
 259         struct  ktr_csw kc;
 260         struct proc *p = current_proc();        /* XXX */
 261
 262         p->p_traceflag |= KTRFAC_ACTIVE;
 263         kth = ktrgetheader(KTR_CSW);
 264         kc.out = out;
 265         kc.user = user;
 266         kth->ktr_buf = (caddr_t)&kc;
 267         kth->ktr_len = sizeof (struct ktr_csw);
 268
 269         ktrwrite(vp, kth, NULL, funnel_type);
 270         FREE(kth, M_KTRACE);
 271         p->p_traceflag &= ~KTRFAC_ACTIVE;
 272 }
 273 #endif /* KTRACE */
 274
 275 /* Interface and common routines */
 276
 277 /*
 278  * ktrace system call
 279  */
 280 struct ktrace_args {
 281         char    *fname;
 282         int     ops;
 283         int     facs;
 284         int     pid;
 285 };
 286 /* ARGSUSED */
 287 int
 288 ktrace(curp, uap, retval)
 289         struct proc *curp;
 290         register struct ktrace_args *uap;
 291         register_t *retval;
 292 {
 293 #if KTRACE
 294         register struct vnode *vp = NULL;
 295         register struct proc *p;
 296         struct pgrp *pg;
 297         int facs = uap->facs & ~KTRFAC_ROOT;
 298         int ops = KTROP(uap->ops);
 299         int descend = uap->ops & KTRFLAG_DESCEND;
 300         int ret = 0;
 301         int error = 0;
 302         struct nameidata nd;
 303
 304         AUDIT_ARG(cmd, uap->ops);
 305         AUDIT_ARG(pid, uap->pid);
 306         AUDIT_ARG(value, uap->facs);
 307         curp->p_traceflag |= KTRFAC_ACTIVE;
 308         if (ops != KTROP_CLEAR) {
 309                 /*
 310                  * an operation which requires a file argument.
 311                  */
 312                 NDINIT(&nd, LOOKUP, (NOFOLLOW|LOCKLEAF), UIO_USERSPACE, uap->fname, curp);
 313                 error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0);
 314                 if (error) {
 315                         curp->p_traceflag &= ~KTRFAC_ACTIVE;
 316                         return (error);
 317                 }
 318                 vp = nd.ni_vp;
 319                 VOP_UNLOCK(vp, 0, curp);
 320                 if (vp->v_type != VREG) {
 321                         (void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
 322                         curp->p_traceflag &= ~KTRFAC_ACTIVE;
 323                         return (EACCES);
 324                 }
 325         }
 326         /*
 327          * Clear all uses of the tracefile
 328          */
 329         if (ops == KTROP_CLEARFILE) {
 330                 LIST_FOREACH(p, &allproc, p_list) {
 331                         if (p->p_tracep == vp) {
 332                                 if (ktrcanset(curp, p)) {
 333                                         struct vnode *tvp = p->p_tracep;
 334                                         /* no more tracing */
 335                                         p->p_traceflag = 0;
 336                                         if (tvp != NULL) {
 337                                                 p->p_tracep = NULL;
 338
 339                                                 VOP_CLOSE(vp, FREAD|FWRITE, curp->p_ucred, curp);
 340                                                 ubc_rele(tvp);
 341                                                 vrele(tvp);
 342                                         }
 343                                 } else
 344                                         error = EPERM;
 345                         }
 346                 }
 347                 goto done;
 348         }
 349
 350         /*
 351          * need something to (un)trace (XXX - why is this here?)
 352          */
 353         if (!facs) {
 354                 error = EINVAL;
 355                 goto done;
 356         }
 357         /*
 358          * do it
 359          */
 360         if (uap->pid < 0) {
 361                 /*
 362                  * by process group
 363                  */
 364                 pg = pgfind(-uap->pid);
 365                 if (pg == NULL) {
 366                         error = ESRCH;
 367                         goto done;
 368                 }
 369                 LIST_FOREACH(p, &pg->pg_members, p_pglist)
 370                         if (descend)
 371                                 ret |= ktrsetchildren(curp, p, ops, facs, vp);
 372                         else
 373                                 ret |= ktrops(curp, p, ops, facs, vp);
 374
 375         } else {
 376                 /*
 377                  * by pid
 378                  */
 379                 p = pfind(uap->pid);
 380                 if (p == NULL) {
 381                         error = ESRCH;
 382                         goto done;
 383                 }
 384                 AUDIT_ARG(process, p);
 385                 if (descend)
 386                         ret |= ktrsetchildren(curp, p, ops, facs, vp);
 387                 else
 388                         ret |= ktrops(curp, p, ops, facs, vp);
 389         }
 390         if (!ret)
 391                 error = EPERM;
 392 done:
 393         if (vp != NULL)
 394                 (void) vn_close(vp, FWRITE, curp->p_ucred, curp);
 395         curp->p_traceflag &= ~KTRFAC_ACTIVE;
 396         return (error);
 397 #else
 398         return ENOSYS;
 399 #endif
 400 }
 401
 402 /*
 403  * utrace system call
 404  */
 405 struct  utrace_args {
 406         const void *    addr;
 407         size_t  len;
 408 };
 409
 410 /* ARGSUSED */
 411 int
 412 utrace(curp, uap, retval)
 413         struct proc *curp;
 414         register struct utrace_args *uap;
 415         register_t *retval;
 416 {
 417 #if KTRACE
 418         struct ktr_header *kth;
 419         struct proc *p = current_proc();        /* XXX */
 420         register caddr_t cp;
 421
 422         if (!KTRPOINT(p, KTR_USER))
 423                 return (0);
 424         if (uap->len > KTR_USER_MAXLEN)
 425                 return (EINVAL);
 426         p->p_traceflag |= KTRFAC_ACTIVE;
 427         kth = ktrgetheader(KTR_USER);
 428         MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
 429         if (!copyin((caddr_t)uap->addr, cp, uap->len)) {
 430                 kth->ktr_buf = cp;
 431                 kth->ktr_len = uap->len;
 432                 ktrwrite(p->p_tracep, kth, NULL, KERNEL_FUNNEL);
 433         }
 434         FREE(kth, M_KTRACE);
 435         FREE(cp, M_KTRACE);
 436         p->p_traceflag &= ~KTRFAC_ACTIVE;
 437
 438         return (0);
 439 #else
 440         return (ENOSYS);
 441 #endif
 442 }
 443
 444 #if KTRACE
 445 static int
 446 ktrops(curp, p, ops, facs, vp)
 447         struct proc *p, *curp;
 448         int ops, facs;
 449         struct vnode *vp;
 450 {
 451         struct vnode *tvp;
 452
 453         if (!ktrcanset(curp, p))
 454                 return (0);
 455         if (ops == KTROP_SET) {
 456                 if (p->p_tracep != vp) {
 457                         /*
 458                          * if trace file already in use, relinquish
 459                          */
 460                         tvp = p->p_tracep;
 461
 462                         if (UBCINFOEXISTS(vp))
 463                                 ubc_hold(vp);
 464                         VREF(vp);
 465
 466                         p->p_tracep = vp;
 467                         if (tvp != NULL) {
 468                                 VOP_CLOSE(tvp, FREAD|FWRITE, p->p_ucred, p);
 469                                 ubc_rele(tvp);
 470                                 vrele(tvp);
 471                         }
 472                 }
 473                 p->p_traceflag |= facs;
 474                 if (curp->p_ucred->cr_uid == 0)
 475                         p->p_traceflag |= KTRFAC_ROOT;
 476         } else {
 477                 /* KTROP_CLEAR */
 478                 if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
 479                         /* no more tracing */
 480                         tvp = p->p_tracep;
 481                         p->p_traceflag = 0;
 482                         if (tvp != NULL) {
 483                                 p->p_tracep = NULL;
 484
 485                                 VOP_CLOSE(tvp, FREAD|FWRITE, p->p_ucred, p);
 486                                 ubc_rele(tvp);
 487                                 vrele(tvp);
 488                         }
 489                 }
 490         }
 491
 492         return (1);
 493 }
 494
 495 static int
 496 ktrsetchildren(curp, top, ops, facs, vp)
 497         struct proc *curp, *top;
 498         int ops, facs;
 499         struct vnode *vp;
 500 {
 501         register struct proc *p;
 502         register int ret = 0;
 503
 504         p = top;
 505         for (;;) {
 506                 ret |= ktrops(curp, p, ops, facs, vp);
 507                 /*
 508                  * If this process has children, descend to them next,
 509                  * otherwise do any siblings, and if done with this level,
 510                  * follow back up the tree (but not past top).
 511                  */
 512                 if (!LIST_EMPTY(&p->p_children))
 513                         p = LIST_FIRST(&p->p_children);
 514                 else for (;;) {
 515                         if (p == top)
 516                                 return (ret);
 517                         if (LIST_NEXT(p, p_sibling)) {
 518                                 p = LIST_NEXT(p, p_sibling);
 519                                 break;
 520                         }
 521                         p = p->p_pptr;
 522                 }
 523         }
 524         /*NOTREACHED*/
 525 }
 526
 527 static void
 528 ktrwrite(vp, kth, uio, funnel_type)
 529         struct vnode *vp;
 530         register struct ktr_header *kth;
 531         struct uio *uio;
 532 {
 533         struct uio auio;
 534         struct iovec aiov[2];
 535         register struct proc *p = current_proc();       /* XXX */
 536         int error;
 537
 538         if (vp == NULL)
 539                 return;
 540
 541         if (funnel_type == -1) {
 542                 funnel_t *f = thread_funnel_get();
 543                 if(f == THR_FUNNEL_NULL)
 544                         funnel_type = NO_FUNNEL;
 545                 else if (f == (funnel_t *)network_flock)
 546                         funnel_type = NETWORK_FUNNEL;
 547                 else if (f == (funnel_t *)kernel_flock)
 548                         funnel_type = KERNEL_FUNNEL;
 549         }
 550
 551         switch (funnel_type) {
 552         case KERNEL_FUNNEL:
 553                 /* Nothing more to do */
 554                 break;
 555         case NETWORK_FUNNEL:
 556                 thread_funnel_switch(NETWORK_FUNNEL, KERNEL_FUNNEL);
 557                 break;
 558         case NO_FUNNEL:
 559                 (void) thread_funnel_set(kernel_flock, TRUE);
 560                 break;
 561         default:
 562                 panic("Invalid funnel (%)", funnel_type);
 563         }
 564         auio.uio_iov = &aiov[0];
 565         auio.uio_offset = 0;
 566         auio.uio_segflg = UIO_SYSSPACE;
 567         auio.uio_rw = UIO_WRITE;
 568         aiov[0].iov_base = (caddr_t)kth;
 569         aiov[0].iov_len = sizeof(struct ktr_header);
 570         auio.uio_resid = sizeof(struct ktr_header);
 571         auio.uio_iovcnt = 1;
 572         auio.uio_procp = current_proc();
 573         if (kth->ktr_len > 0) {
 574                 auio.uio_iovcnt++;
 575                 aiov[1].iov_base = kth->ktr_buf;
 576                 aiov[1].iov_len = kth->ktr_len;
 577                 auio.uio_resid += kth->ktr_len;
 578                 if (uio != NULL)
 579                         kth->ktr_len += uio->uio_resid;
 580         }
 581         error = vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
 582         if (error)
 583                 goto bad;
 584         (void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
 585         error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
 586         if (error == 0 && uio != NULL) {
 587                 (void)VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
 588                 error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
 589         }
 590         VOP_UNLOCK(vp, 0, p);
 591         if (!error) {
 592                 switch (funnel_type) {
 593                 case KERNEL_FUNNEL:
 594                         /* Nothing more to do */
 595                         break;
 596                 case NETWORK_FUNNEL:
 597                         thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
 598                         /* switch funnel to NETWORK_FUNNEL */
 599                         break;
 600                 case NO_FUNNEL:
 601                          (void) thread_funnel_set(kernel_flock, FALSE);
 602                         break;
 603                 default:
 604                         panic("Invalid funnel (%)", funnel_type);
 605                 }
 606                 return;
 607         }
 608
 609 bad:
 610         /*
 611          * If error encountered, give up tracing on this vnode.
 612          */
 613         log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
 614             error);
 615         LIST_FOREACH(p, &allproc, p_list) {
 616                 if (p->p_tracep == vp) {
 617                         p->p_tracep = NULL;
 618                         p->p_traceflag = 0;
 619
 620                         VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p);
 621                         ubc_rele(vp);
 622                         vrele(vp);
 623                 }
 624         }
 625
 626         switch (funnel_type) {
 627         case KERNEL_FUNNEL:
 628                 /* Nothing more to do */
 629                 break;
 630         case NETWORK_FUNNEL:
 631                 thread_funnel_switch(KERNEL_FUNNEL, NETWORK_FUNNEL);
 632                 /* switch funnel to NETWORK_FUNNEL */
 633                 break;
 634         case NO_FUNNEL:
 635                  (void) thread_funnel_set(kernel_flock, FALSE);
 636                 break;
 637         default:
 638                 panic("Invalid funnel (%)", funnel_type);
 639         }
 640 }
 641
 642 /*
 643  * Return true if caller has permission to set the ktracing state
 644  * of target.  Essentially, the target can't possess any
 645  * more permissions than the caller.  KTRFAC_ROOT signifies that
 646  * root previously set the tracing status on the target process, and
 647  * so, only root may further change it.
 648  *
 649  * TODO: check groups.  use caller effective gid.
 650  */
 651 static int
 652 ktrcanset(callp, targetp)
 653         struct proc *callp, *targetp;
 654 {
 655         register struct pcred *caller = callp->p_cred;
 656         register struct pcred *target = targetp->p_cred;
 657
 658         if (!PRISON_CHECK(callp, targetp))
 659                 return (0);
 660         if ((caller->pc_ucred->cr_uid == target->p_ruid &&
 661              target->p_ruid == target->p_svuid &&
 662              caller->p_rgid == target->p_rgid &&        /* XXX */
 663              target->p_rgid == target->p_svgid &&
 664              (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
 665              (targetp->p_flag & P_SUGID) == 0) ||
 666              caller->pc_ucred->cr_uid == 0)
 667                 return (1);
 668
 669         return (0);
 670 }
 671
 672 #endif /* KTRACE */