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Annotation of XNU/bsd/kern/kern_ktrace.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2000 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:  */
        !            57: 
        !            58: 
        !            59: #include <sys/param.h>
        !            60: #include <sys/systm.h>
        !            61: #include <sys/proc.h>
        !            62: #include <sys/file.h>
        !            63: #include <sys/namei.h>
        !            64: #include <sys/vnode.h>
        !            65: #include <sys/ktrace.h>
        !            66: #include <sys/malloc.h>
        !            67: #include <sys/syslog.h>
        !            68: 
        !            69: #include <sys/mount.h>
        !            70: 
        !            71: #if KTRACE
        !            72: 
        !            73: struct ktr_header *
        !            74: ktrgetheader(type)
        !            75:        int type;
        !            76: {
        !            77:        register struct ktr_header *kth;
        !            78:        struct proc *p = current_proc();        /* XXX */
        !            79: 
        !            80:        MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header), 
        !            81:                M_TEMP, M_WAITOK);
        !            82:        kth->ktr_type = type;
        !            83:        microtime(&kth->ktr_time);
        !            84:        kth->ktr_pid = p->p_pid;
        !            85:        bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN);
        !            86:        return (kth);
        !            87: }
        !            88: 
        !            89: void
        !            90: ktrsyscall(vp, code, argsize, args)
        !            91:        struct vnode *vp;
        !            92:        register_t code;
        !            93:        size_t argsize;
        !            94:        register_t args[];
        !            95: {
        !            96:        struct  ktr_header *kth;
        !            97:        struct  ktr_syscall *ktp;
        !            98:        register len = sizeof(struct ktr_syscall) + argsize;
        !            99:        struct proc *p = current_proc();        /* XXX */
        !           100:        register_t *argp;
        !           101:        int i;
        !           102: 
        !           103:        p->p_traceflag |= KTRFAC_ACTIVE;
        !           104:        kth = ktrgetheader(KTR_SYSCALL);
        !           105:        MALLOC(ktp, struct ktr_syscall *, len, M_TEMP, M_WAITOK);
        !           106:        ktp->ktr_code = code;
        !           107:        ktp->ktr_argsize = argsize;
        !           108:        argp = (register_t *)((char *)ktp + sizeof(struct ktr_syscall));
        !           109:        for (i = 0; i < (argsize / sizeof *argp); i++)
        !           110:                *argp++ = args[i];
        !           111:        kth->ktr_buf = (caddr_t)ktp;
        !           112:        kth->ktr_len = len;
        !           113:        ktrwrite(vp, kth);
        !           114:        FREE(ktp, M_TEMP);
        !           115:        FREE(kth, M_TEMP);
        !           116:        p->p_traceflag &= ~KTRFAC_ACTIVE;
        !           117: }
        !           118: 
        !           119: void
        !           120: ktrsysret(vp, code, error, retval)
        !           121:        struct vnode *vp;
        !           122:        register_t code;
        !           123:        int error;
        !           124:        register_t retval;
        !           125: {
        !           126:        struct ktr_header *kth;
        !           127:        struct ktr_sysret ktp;
        !           128:        struct proc *p = current_proc();        /* XXX */
        !           129: 
        !           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_buf = (caddr_t)&ktp;
        !           137:        kth->ktr_len = sizeof(struct ktr_sysret);
        !           138: 
        !           139:        ktrwrite(vp, kth);
        !           140:        FREE(kth, M_TEMP);
        !           141:        p->p_traceflag &= ~KTRFAC_ACTIVE;
        !           142: }
        !           143: 
        !           144: void
        !           145: ktrnamei(vp, path)
        !           146:        struct vnode *vp;
        !           147:        char *path;
        !           148: {
        !           149:        struct ktr_header *kth;
        !           150:        struct proc *p = current_proc();        /* XXX */
        !           151: 
        !           152:        p->p_traceflag |= KTRFAC_ACTIVE;
        !           153:        kth = ktrgetheader(KTR_NAMEI);
        !           154:        kth->ktr_len = strlen(path);
        !           155:        kth->ktr_buf = path;
        !           156: 
        !           157:        ktrwrite(vp, kth);
        !           158:        FREE(kth, M_TEMP);
        !           159:        p->p_traceflag &= ~KTRFAC_ACTIVE;
        !           160: }
        !           161: 
        !           162: void
        !           163: ktrgenio(vp, fd, rw, iov, len, error)
        !           164:        struct vnode *vp;
        !           165:        int fd;
        !           166:        enum uio_rw rw;
        !           167:        register struct iovec *iov;
        !           168:        int len, error;
        !           169: {
        !           170:        struct ktr_header *kth;
        !           171:        register struct ktr_genio *ktp;
        !           172:        register caddr_t cp;
        !           173:        register int resid = len, cnt;
        !           174:        struct proc *p = current_proc();        /* XXX */
        !           175:        
        !           176:        if (error)
        !           177:                return;
        !           178:        p->p_traceflag |= KTRFAC_ACTIVE;
        !           179:        kth = ktrgetheader(KTR_GENIO);
        !           180:        MALLOC(ktp, struct ktr_genio *, sizeof(struct ktr_genio) + len,
        !           181:                M_TEMP, M_WAITOK);
        !           182:        ktp->ktr_fd = fd;
        !           183:        ktp->ktr_rw = rw;
        !           184:        cp = (caddr_t)((char *)ktp + sizeof (struct ktr_genio));
        !           185:        while (resid > 0) {
        !           186:                if ((cnt = iov->iov_len) > resid)
        !           187:                        cnt = resid;
        !           188:                if (copyin(iov->iov_base, cp, (unsigned)cnt))
        !           189:                        goto done;
        !           190:                cp += cnt;
        !           191:                resid -= cnt;
        !           192:                iov++;
        !           193:        }
        !           194:        kth->ktr_buf = (caddr_t)ktp;
        !           195:        kth->ktr_len = sizeof (struct ktr_genio) + len;
        !           196: 
        !           197:        ktrwrite(vp, kth);
        !           198: done:
        !           199:        FREE(kth, M_TEMP);
        !           200:        FREE(ktp, M_TEMP);
        !           201:        p->p_traceflag &= ~KTRFAC_ACTIVE;
        !           202: }
        !           203: 
        !           204: void
        !           205: ktrpsig(vp, sig, action, mask, code)
        !           206:        struct vnode *vp;
        !           207:        int sig;
        !           208:        sig_t action;
        !           209:        int mask, code;
        !           210: {
        !           211:        struct ktr_header *kth;
        !           212:        struct ktr_psig kp;
        !           213:        struct proc *p = current_proc();        /* XXX */
        !           214: 
        !           215:        p->p_traceflag |= KTRFAC_ACTIVE;
        !           216:        kth = ktrgetheader(KTR_PSIG);
        !           217:        kp.signo = (char)sig;
        !           218:        kp.action = action;
        !           219:        kp.mask = mask;
        !           220:        kp.code = code;
        !           221:        kth->ktr_buf = (caddr_t)&kp;
        !           222:        kth->ktr_len = sizeof (struct ktr_psig);
        !           223: 
        !           224:        ktrwrite(vp, kth);
        !           225:        FREE(kth, M_TEMP);
        !           226:        p->p_traceflag &= ~KTRFAC_ACTIVE;
        !           227: }
        !           228: 
        !           229: void
        !           230: ktrcsw(vp, out, user)
        !           231:        struct vnode *vp;
        !           232:        int out, user;
        !           233: {
        !           234:        struct ktr_header *kth;
        !           235:        struct  ktr_csw kc;
        !           236:        struct proc *p = current_proc();        /* XXX */
        !           237: 
        !           238:        p->p_traceflag |= KTRFAC_ACTIVE;
        !           239:        kth = ktrgetheader(KTR_CSW);
        !           240:        kc.out = out;
        !           241:        kc.user = user;
        !           242:        kth->ktr_buf = (caddr_t)&kc;
        !           243:        kth->ktr_len = sizeof (struct ktr_csw);
        !           244: 
        !           245:        ktrwrite(vp, kth);
        !           246:        FREE(kth, M_TEMP);
        !           247:        p->p_traceflag &= ~KTRFAC_ACTIVE;
        !           248: }
        !           249: 
        !           250: /* Interface and common routines */
        !           251: 
        !           252: /*
        !           253:  * ktrace system call
        !           254:  */
        !           255: struct ktrace_args {
        !           256:        char *  fname;
        !           257:        int             ops;
        !           258:        int             facs;
        !           259:        int             pid;
        !           260: };
        !           261: /* ARGSUSED */
        !           262: int
        !           263: ktrace(curp, uap, retval)
        !           264:        struct proc *curp;
        !           265:        register struct ktrace_args *uap;
        !           266:        register_t *retval;
        !           267: {
        !           268:        register struct vnode *vp = NULL;
        !           269:        register struct proc *p;
        !           270:        struct pgrp *pg;
        !           271:        int facs = SCARG(uap, facs) & ~KTRFAC_ROOT;
        !           272:        int ops = KTROP(SCARG(uap, ops));
        !           273:        int descend = SCARG(uap, ops) & KTRFLAG_DESCEND;
        !           274:        int ret = 0;
        !           275:        int error = 0;
        !           276:        struct nameidata nd;
        !           277: 
        !           278:        curp->p_traceflag |= KTRFAC_ACTIVE;
        !           279:        if (ops != KTROP_CLEAR) {
        !           280:                /*
        !           281:                 * an operation which requires a file argument.
        !           282:                 */
        !           283:                NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, fname),
        !           284:                    curp);
        !           285:                if (error = vn_open(&nd, FREAD|FWRITE, 0)) {
        !           286:                        curp->p_traceflag &= ~KTRFAC_ACTIVE;
        !           287:                        return (error);
        !           288:                }
        !           289:                vp = nd.ni_vp;
        !           290:                VOP_UNLOCK(vp, 0, p);
        !           291:                if (vp->v_type != VREG) {
        !           292:                        (void) vn_close(vp, FREAD|FWRITE, curp->p_ucred, curp);
        !           293:                        curp->p_traceflag &= ~KTRFAC_ACTIVE;
        !           294:                        return (EACCES);
        !           295:                }
        !           296:        }
        !           297:        /*
        !           298:         * Clear all uses of the tracefile
        !           299:         */
        !           300:        if (ops == KTROP_CLEARFILE) {
        !           301:                for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
        !           302:                        if (p->p_tracep == vp) {
        !           303:                                if (ktrcanset(curp, p)) {
        !           304:                                        p->p_tracep = NULL;
        !           305:                                        p->p_traceflag = 0;
        !           306:                                        (void) vn_close(vp, FREAD|FWRITE,
        !           307:                                                p->p_ucred, p);
        !           308:                                } else
        !           309:                                        error = EPERM;
        !           310:                        }
        !           311:                }
        !           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 (SCARG(uap, pid) < 0) {
        !           325:                /*
        !           326:                 * by process group
        !           327:                 */
        !           328:                pg = pgfind(-SCARG(uap, pid));
        !           329:                if (pg == NULL) {
        !           330:                        error = ESRCH;
        !           331:                        goto done;
        !           332:                }
        !           333:                for (p = pg->pg_members.lh_first; p != 0; p = p->p_pglist.le_next)
        !           334:                        if (descend)
        !           335:                                ret |= ktrsetchildren(curp, p, ops, facs, vp);
        !           336:                        else 
        !           337:                                ret |= ktrops(curp, p, ops, facs, vp);
        !           338:                                        
        !           339:        } else {
        !           340:                /*
        !           341:                 * by pid
        !           342:                 */
        !           343:                p = pfind(SCARG(uap, pid));
        !           344:                if (p == NULL) {
        !           345:                        error = ESRCH;
        !           346:                        goto done;
        !           347:                }
        !           348:                if (descend)
        !           349:                        ret |= ktrsetchildren(curp, p, ops, facs, vp);
        !           350:                else
        !           351:                        ret |= ktrops(curp, p, ops, facs, vp);
        !           352:        }
        !           353:        if (!ret)
        !           354:                error = EPERM;
        !           355: done:
        !           356:        if (vp != NULL)
        !           357:                (void) vn_close(vp, FWRITE, curp->p_ucred, curp);
        !           358:        curp->p_traceflag &= ~KTRFAC_ACTIVE;
        !           359:        return (error);
        !           360: }
        !           361: 
        !           362: int
        !           363: ktrops(curp, p, ops, facs, vp)
        !           364:        struct proc *p, *curp;
        !           365:        int ops, facs;
        !           366:        struct vnode *vp;
        !           367: {
        !           368: 
        !           369:        if (!ktrcanset(curp, p))
        !           370:                return (0);
        !           371:        if (ops == KTROP_SET) {
        !           372:                if (p->p_tracep != vp) { 
        !           373:                        /*
        !           374:                         * if trace file already in use, relinquish
        !           375:                         */
        !           376:                        if (p->p_tracep != NULL)
        !           377:                                vrele(p->p_tracep);
        !           378:                        VREF(vp);
        !           379:                        p->p_tracep = vp;
        !           380:                }
        !           381:                p->p_traceflag |= facs;
        !           382:                if (curp->p_ucred->cr_uid == 0)
        !           383:                        p->p_traceflag |= KTRFAC_ROOT;
        !           384:        } else {        
        !           385:                /* KTROP_CLEAR */
        !           386:                if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
        !           387:                        /* no more tracing */
        !           388:                        p->p_traceflag = 0;
        !           389:                        if (p->p_tracep != NULL) {
        !           390:                                vrele(p->p_tracep);
        !           391:                                p->p_tracep = NULL;
        !           392:                        }
        !           393:                }
        !           394:        }
        !           395: 
        !           396:        return (1);
        !           397: }
        !           398: 
        !           399: ktrsetchildren(curp, top, ops, facs, vp)
        !           400:        struct proc *curp, *top;
        !           401:        int ops, facs;
        !           402:        struct vnode *vp;
        !           403: {
        !           404:        register struct proc *p;
        !           405:        register int ret = 0;
        !           406: 
        !           407:        p = top;
        !           408:        for (;;) {
        !           409:                ret |= ktrops(curp, p, ops, facs, vp);
        !           410:                /*
        !           411:                 * If this process has children, descend to them next,
        !           412:                 * otherwise do any siblings, and if done with this level,
        !           413:                 * follow back up the tree (but not past top).
        !           414:                 */
        !           415:                if (p->p_children.lh_first)
        !           416:                        p = p->p_children.lh_first;
        !           417:                else for (;;) {
        !           418:                        if (p == top)
        !           419:                                return (ret);
        !           420:                        if (p->p_sibling.le_next) {
        !           421:                                p = p->p_sibling.le_next;
        !           422:                                break;
        !           423:                        }
        !           424:                        p = p->p_pptr;
        !           425:                }
        !           426:        }
        !           427:        /*NOTREACHED*/
        !           428: }
        !           429: 
        !           430: ktrwrite(vp, kth)
        !           431:        struct vnode *vp;
        !           432:        register struct ktr_header *kth;
        !           433: {
        !           434:        struct uio auio;
        !           435:        struct iovec aiov[2];
        !           436:        register struct proc *p = current_proc();       /* XXX */
        !           437:        int error;
        !           438: 
        !           439:        if (vp == NULL)
        !           440:                return;
        !           441:        auio.uio_iov = &aiov[0];
        !           442:        auio.uio_offset = 0;
        !           443:        auio.uio_segflg = UIO_SYSSPACE;
        !           444:        auio.uio_rw = UIO_WRITE;
        !           445:        aiov[0].iov_base = (caddr_t)kth;
        !           446:        aiov[0].iov_len = sizeof(struct ktr_header);
        !           447:        auio.uio_resid = sizeof(struct ktr_header);
        !           448:        auio.uio_iovcnt = 1;
        !           449:        auio.uio_procp = (struct proc *)0;
        !           450:        if (kth->ktr_len > 0) {
        !           451:                auio.uio_iovcnt++;
        !           452:                aiov[1].iov_base = kth->ktr_buf;
        !           453:                aiov[1].iov_len = kth->ktr_len;
        !           454:                auio.uio_resid += kth->ktr_len;
        !           455:        }
        !           456:        vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
        !           457:        error = VOP_WRITE(vp, &auio, IO_UNIT|IO_APPEND, p->p_ucred);
        !           458:        VOP_UNLOCK(vp, 0, p);
        !           459:        if (!error)
        !           460:                return;
        !           461:        /*
        !           462:         * If error encountered, give up tracing on this vnode.
        !           463:         */
        !           464:        log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
        !           465:            error);
        !           466:        for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
        !           467:                if (p->p_tracep == vp) {
        !           468:                        p->p_tracep = NULL;
        !           469:                        p->p_traceflag = 0;
        !           470:                        vrele(vp);
        !           471:                }
        !           472:        }
        !           473: }
        !           474: 
        !           475: /*
        !           476:  * Return true if caller has permission to set the ktracing state
        !           477:  * of target.  Essentially, the target can't possess any
        !           478:  * more permissions than the caller.  KTRFAC_ROOT signifies that
        !           479:  * root previously set the tracing status on the target process, and 
        !           480:  * so, only root may further change it.
        !           481:  *
        !           482:  * TODO: check groups.  use caller effective gid.
        !           483:  */
        !           484: ktrcanset(callp, targetp)
        !           485:        struct proc *callp, *targetp;
        !           486: {
        !           487:        register struct pcred *caller = callp->p_cred;
        !           488:        register struct pcred *target = targetp->p_cred;
        !           489: 
        !           490:        if ((caller->pc_ucred->cr_uid == target->p_ruid &&
        !           491:             target->p_ruid == target->p_svuid &&
        !           492:             caller->p_rgid == target->p_rgid &&        /* XXX */
        !           493:             target->p_rgid == target->p_svgid &&
        !           494:             (targetp->p_traceflag & KTRFAC_ROOT) == 0) ||
        !           495:             caller->pc_ucred->cr_uid == 0)
        !           496:                return (1);
        !           497: 
        !           498:        return (0);
        !           499: }
        !           500: 
        !           501: #endif

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