File:  [DragonFly] / src / sys / kern / kern_ktrace.c
Revision 1.12: download - view: text, annotated - select for diffs
Sat Feb 14 12:14:30 2004 UTC (10 years, 7 months ago) by eirikn
Branches: MAIN
CVS tags: HEAD
Replace K&R style functions with ANSI C style functions.

    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:  * $DragonFly: src/sys/kern/kern_ktrace.c,v 1.12 2004/02/14 12:14:30 eirikn Exp $
   36:  */
   37: 
   38: #include "opt_ktrace.h"
   39: 
   40: #include <sys/param.h>
   41: #include <sys/systm.h>
   42: #include <sys/sysproto.h>
   43: #include <sys/kernel.h>
   44: #include <sys/proc.h>
   45: #include <sys/fcntl.h>
   46: #include <sys/lock.h>
   47: #include <sys/namei.h>
   48: #include <sys/vnode.h>
   49: #include <sys/ktrace.h>
   50: #include <sys/malloc.h>
   51: #include <sys/syslog.h>
   52: #include <sys/sysent.h>
   53: 
   54: #include <vm/vm_zone.h>
   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(int type)
   67: {
   68: 	struct ktr_header *kth;
   69: 	struct proc *p = curproc;	/* XXX */
   70: 
   71: 	MALLOC(kth, struct ktr_header *, sizeof (struct ktr_header),
   72: 		M_KTRACE, M_WAITOK);
   73: 	kth->ktr_type = type;
   74: 	microtime(&kth->ktr_time);
   75: 	kth->ktr_pid = p->p_pid;
   76: 	bcopy(p->p_comm, kth->ktr_comm, MAXCOMLEN + 1);
   77: 	return (kth);
   78: }
   79: 
   80: void
   81: ktrsyscall(struct vnode *vp, int code, int narg, register_t args[])
   82: {
   83: 	struct	ktr_header *kth;
   84: 	struct	ktr_syscall *ktp;
   85: 	int len = offsetof(struct ktr_syscall, ktr_args) +
   86: 	    (narg * sizeof(register_t));
   87: 	struct proc *p = curproc;	/* XXX */
   88: 	register_t *argp;
   89: 	int i;
   90: 
   91: 	p->p_traceflag |= KTRFAC_ACTIVE;
   92: 	kth = ktrgetheader(KTR_SYSCALL);
   93: 	MALLOC(ktp, struct ktr_syscall *, len, M_KTRACE, M_WAITOK);
   94: 	ktp->ktr_code = code;
   95: 	ktp->ktr_narg = narg;
   96: 	argp = &ktp->ktr_args[0];
   97: 	for (i = 0; i < narg; i++)
   98: 		*argp++ = args[i];
   99: 	kth->ktr_buf = (caddr_t)ktp;
  100: 	kth->ktr_len = len;
  101: 	ktrwrite(vp, kth, NULL);
  102: 	FREE(ktp, M_KTRACE);
  103: 	FREE(kth, M_KTRACE);
  104: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  105: }
  106: 
  107: void
  108: ktrsysret(struct vnode *vp, int code, int error, register_t retval)
  109: {
  110: 	struct ktr_header *kth;
  111: 	struct ktr_sysret ktp;
  112: 	struct proc *p = curproc;	/* XXX */
  113: 
  114: 	p->p_traceflag |= KTRFAC_ACTIVE;
  115: 	kth = ktrgetheader(KTR_SYSRET);
  116: 	ktp.ktr_code = code;
  117: 	ktp.ktr_error = error;
  118: 	ktp.ktr_retval = retval;		/* what about val2 ? */
  119: 
  120: 	kth->ktr_buf = (caddr_t)&ktp;
  121: 	kth->ktr_len = sizeof(struct ktr_sysret);
  122: 
  123: 	ktrwrite(vp, kth, NULL);
  124: 	FREE(kth, M_KTRACE);
  125: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  126: }
  127: 
  128: void
  129: ktrnamei(struct vnode *vp, char *path)
  130: {
  131: 	struct ktr_header *kth;
  132: 	struct proc *p = curproc;	/* XXX */
  133: 
  134: 	/*
  135: 	 * don't let vp get ripped out from under us
  136: 	 */
  137: 	if (vp)
  138: 		VREF(vp);
  139: 	p->p_traceflag |= KTRFAC_ACTIVE;
  140: 	kth = ktrgetheader(KTR_NAMEI);
  141: 	kth->ktr_len = strlen(path);
  142: 	kth->ktr_buf = path;
  143: 
  144: 	ktrwrite(vp, kth, NULL);
  145: 	if (vp)
  146: 		vrele(vp);
  147: 	FREE(kth, M_KTRACE);
  148: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  149: }
  150: 
  151: void
  152: ktrgenio(struct vnode *vp, int fd, enum uio_rw rw, struct uio *uio, int error)
  153: {
  154: 	struct ktr_header *kth;
  155: 	struct ktr_genio ktg;
  156: 	struct proc *p = curproc;	/* XXX */
  157: 
  158: 	if (error)
  159: 		return;
  160: 	/*
  161: 	 * don't let p_tracep get ripped out from under us
  162: 	 */
  163: 	if (vp)
  164: 		VREF(vp);
  165: 	p->p_traceflag |= KTRFAC_ACTIVE;
  166: 	kth = ktrgetheader(KTR_GENIO);
  167: 	ktg.ktr_fd = fd;
  168: 	ktg.ktr_rw = rw;
  169: 	kth->ktr_buf = (caddr_t)&ktg;
  170: 	kth->ktr_len = sizeof(struct ktr_genio);
  171: 	uio->uio_offset = 0;
  172: 	uio->uio_rw = UIO_WRITE;
  173: 
  174: 	ktrwrite(vp, kth, uio);
  175: 	if (vp)
  176: 		vrele(vp);
  177: 	FREE(kth, M_KTRACE);
  178: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  179: }
  180: 
  181: void
  182: ktrpsig(struct vnode *vp, int sig, sig_t action, sigset_t *mask, int code)
  183: {
  184: 	struct ktr_header *kth;
  185: 	struct ktr_psig	kp;
  186: 	struct proc *p = curproc;	/* XXX */
  187: 
  188: 	/*
  189: 	 * don't let vp get ripped out from under us
  190: 	 */
  191: 	if (vp)
  192: 		VREF(vp);
  193: 	p->p_traceflag |= KTRFAC_ACTIVE;
  194: 	kth = ktrgetheader(KTR_PSIG);
  195: 	kp.signo = (char)sig;
  196: 	kp.action = action;
  197: 	kp.mask = *mask;
  198: 	kp.code = code;
  199: 	kth->ktr_buf = (caddr_t)&kp;
  200: 	kth->ktr_len = sizeof (struct ktr_psig);
  201: 
  202: 	ktrwrite(vp, kth, NULL);
  203: 	if (vp)
  204: 		vrele(vp);
  205: 	FREE(kth, M_KTRACE);
  206: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  207: }
  208: 
  209: void
  210: ktrcsw(struct vnode *vp, int out, int user)
  211: {
  212: 	struct ktr_header *kth;
  213: 	struct	ktr_csw kc;
  214: 	struct proc *p = curproc;	/* XXX */
  215: 
  216: 	/*
  217: 	 * don't let vp get ripped out from under us
  218: 	 */
  219: 	if (vp)
  220: 		VREF(vp);
  221: 	p->p_traceflag |= KTRFAC_ACTIVE;
  222: 	kth = ktrgetheader(KTR_CSW);
  223: 	kc.out = out;
  224: 	kc.user = user;
  225: 	kth->ktr_buf = (caddr_t)&kc;
  226: 	kth->ktr_len = sizeof (struct ktr_csw);
  227: 
  228: 	ktrwrite(vp, kth, NULL);
  229: 	if (vp)
  230: 		vrele(vp);
  231: 	FREE(kth, M_KTRACE);
  232: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  233: }
  234: #endif
  235: 
  236: /* Interface and common routines */
  237: 
  238: /*
  239:  * ktrace system call
  240:  */
  241: /* ARGSUSED */
  242: int
  243: ktrace(struct ktrace_args *uap)
  244: {
  245: #ifdef KTRACE
  246: 	struct thread *td = curthread;
  247: 	struct proc *curp = td->td_proc;
  248: 	struct vnode *vp = NULL;
  249: 	struct proc *p;
  250: 	struct pgrp *pg;
  251: 	int facs = uap->facs & ~KTRFAC_ROOT;
  252: 	int ops = KTROP(uap->ops);
  253: 	int descend = uap->ops & KTRFLAG_DESCEND;
  254: 	int ret = 0;
  255: 	int error = 0;
  256: 	struct nameidata nd;
  257: 
  258: 	curp->p_traceflag |= KTRFAC_ACTIVE;
  259: 	if (ops != KTROP_CLEAR) {
  260: 		/*
  261: 		 * an operation which requires a file argument.
  262: 		 */
  263: 		NDINIT(&nd, NAMEI_LOOKUP, 0, UIO_USERSPACE, uap->fname, td);
  264: 		error = vn_open(&nd, FREAD|FWRITE|O_NOFOLLOW, 0);
  265: 		if (error) {
  266: 			curp->p_traceflag &= ~KTRFAC_ACTIVE;
  267: 			return (error);
  268: 		}
  269: 		NDFREE(&nd, NDF_ONLY_PNBUF);
  270: 		vp = nd.ni_vp;
  271: 		VOP_UNLOCK(vp, 0, td);
  272: 		if (vp->v_type != VREG) {
  273: 			(void) vn_close(vp, FREAD|FWRITE, td);
  274: 			curp->p_traceflag &= ~KTRFAC_ACTIVE;
  275: 			return (EACCES);
  276: 		}
  277: 	}
  278: 	/*
  279: 	 * Clear all uses of the tracefile.  XXX umm, what happens to the
  280: 	 * loop if vn_close() blocks?
  281: 	 */
  282: 	if (ops == KTROP_CLEARFILE) {
  283: 		FOREACH_PROC_IN_SYSTEM(p) {
  284: 			if (p->p_tracep == vp) {
  285: 				if (ktrcanset(curp, p) && p->p_tracep == vp) {
  286: 					p->p_tracep = NULL;
  287: 					p->p_traceflag = 0;
  288: 					(void) vn_close(vp, FREAD|FWRITE, td);
  289: 				} else {
  290: 					error = EPERM;
  291: 				}
  292: 			}
  293: 		}
  294: 		goto done;
  295: 	}
  296: 	/*
  297: 	 * need something to (un)trace (XXX - why is this here?)
  298: 	 */
  299: 	if (!facs) {
  300: 		error = EINVAL;
  301: 		goto done;
  302: 	}
  303: 	/*
  304: 	 * do it
  305: 	 */
  306: 	if (uap->pid < 0) {
  307: 		/*
  308: 		 * by process group
  309: 		 */
  310: 		pg = pgfind(-uap->pid);
  311: 		if (pg == NULL) {
  312: 			error = ESRCH;
  313: 			goto done;
  314: 		}
  315: 		LIST_FOREACH(p, &pg->pg_members, p_pglist)
  316: 			if (descend)
  317: 				ret |= ktrsetchildren(curp, p, ops, facs, vp);
  318: 			else
  319: 				ret |= ktrops(curp, p, ops, facs, vp);
  320: 
  321: 	} else {
  322: 		/*
  323: 		 * by pid
  324: 		 */
  325: 		p = pfind(uap->pid);
  326: 		if (p == NULL) {
  327: 			error = ESRCH;
  328: 			goto done;
  329: 		}
  330: 		if (descend)
  331: 			ret |= ktrsetchildren(curp, p, ops, facs, vp);
  332: 		else
  333: 			ret |= ktrops(curp, p, ops, facs, vp);
  334: 	}
  335: 	if (!ret)
  336: 		error = EPERM;
  337: done:
  338: 	if (vp != NULL)
  339: 		(void) vn_close(vp, FWRITE, td);
  340: 	curp->p_traceflag &= ~KTRFAC_ACTIVE;
  341: 	return (error);
  342: #else
  343: 	return ENOSYS;
  344: #endif
  345: }
  346: 
  347: /*
  348:  * utrace system call
  349:  */
  350: /* ARGSUSED */
  351: int
  352: utrace(struct utrace_args *uap)
  353: {
  354: #ifdef KTRACE
  355: 	struct ktr_header *kth;
  356: 	struct thread *td = curthread;	/* XXX */
  357: 	struct proc *p = td->td_proc;
  358: 	struct vnode *vp;
  359: 	caddr_t cp;
  360: 
  361: 	if (!KTRPOINT(td, KTR_USER))
  362: 		return (0);
  363: 	if (SCARG(uap, len) > KTR_USER_MAXLEN)
  364: 		return (EINVAL);
  365: 	p->p_traceflag |= KTRFAC_ACTIVE;
  366: 	/*
  367: 	 * don't let p_tracep get ripped out from under us while we are
  368: 	 * writing.
  369: 	 */
  370: 	if ((vp = p->p_tracep) != NULL)
  371: 		VREF(vp);
  372: 	kth = ktrgetheader(KTR_USER);
  373: 	MALLOC(cp, caddr_t, uap->len, M_KTRACE, M_WAITOK);
  374: 	if (!copyin(uap->addr, cp, uap->len)) {
  375: 		kth->ktr_buf = cp;
  376: 		kth->ktr_len = uap->len;
  377: 		ktrwrite(vp, kth, NULL);
  378: 	}
  379: 	if (vp)
  380: 		vrele(vp);
  381: 	FREE(kth, M_KTRACE);
  382: 	FREE(cp, M_KTRACE);
  383: 	p->p_traceflag &= ~KTRFAC_ACTIVE;
  384: 
  385: 	return (0);
  386: #else
  387: 	return (ENOSYS);
  388: #endif
  389: }
  390: 
  391: #ifdef KTRACE
  392: static int
  393: ktrops(struct proc *curp, struct proc *p, int ops, int facs, struct vnode *vp)
  394: {
  395: 
  396: 	if (!ktrcanset(curp, p))
  397: 		return (0);
  398: 	if (ops == KTROP_SET) {
  399: 		if (p->p_tracep != vp) {
  400: 			struct vnode *vtmp;
  401: 
  402: 			/*
  403: 			 * if trace file already in use, relinquish
  404: 			 */
  405: 			VREF(vp);
  406: 			while ((vtmp = p->p_tracep) != NULL) {
  407: 				p->p_tracep = NULL;
  408: 				vrele(vtmp);
  409: 			}
  410: 			p->p_tracep = vp;
  411: 		}
  412: 		p->p_traceflag |= facs;
  413: 		if (curp->p_ucred->cr_uid == 0)
  414: 			p->p_traceflag |= KTRFAC_ROOT;
  415: 	} else {
  416: 		/* KTROP_CLEAR */
  417: 		if (((p->p_traceflag &= ~facs) & KTRFAC_MASK) == 0) {
  418: 			struct vnode *vtmp;
  419: 
  420: 			/* no more tracing */
  421: 			p->p_traceflag = 0;
  422: 			if ((vtmp = p->p_tracep) != NULL) {
  423: 				p->p_tracep = NULL;
  424: 				vrele(vtmp);
  425: 			}
  426: 		}
  427: 	}
  428: 
  429: 	return (1);
  430: }
  431: 
  432: static int
  433: ktrsetchildren(struct proc *curp, struct proc *top, int ops, int facs,
  434:                struct vnode *vp)
  435: {
  436: 	struct proc *p;
  437: 	int ret = 0;
  438: 
  439: 	p = top;
  440: 	for (;;) {
  441: 		ret |= ktrops(curp, p, ops, facs, vp);
  442: 		/*
  443: 		 * If this process has children, descend to them next,
  444: 		 * otherwise do any siblings, and if done with this level,
  445: 		 * follow back up the tree (but not past top).
  446: 		 */
  447: 		if (!LIST_EMPTY(&p->p_children))
  448: 			p = LIST_FIRST(&p->p_children);
  449: 		else for (;;) {
  450: 			if (p == top)
  451: 				return (ret);
  452: 			if (LIST_NEXT(p, p_sibling)) {
  453: 				p = LIST_NEXT(p, p_sibling);
  454: 				break;
  455: 			}
  456: 			p = p->p_pptr;
  457: 		}
  458: 	}
  459: 	/*NOTREACHED*/
  460: }
  461: 
  462: static void
  463: ktrwrite(struct vnode *vp, struct ktr_header *kth, struct uio *uio)
  464: {
  465: 	struct uio auio;
  466: 	struct iovec aiov[2];
  467: 	struct thread *td = curthread;
  468: 	struct proc *p = td->td_proc;	/* XXX */
  469: 	int error;
  470: 
  471: 	if (vp == NULL)
  472: 		return;
  473: 	auio.uio_iov = &aiov[0];
  474: 	auio.uio_offset = 0;
  475: 	auio.uio_segflg = UIO_SYSSPACE;
  476: 	auio.uio_rw = UIO_WRITE;
  477: 	aiov[0].iov_base = (caddr_t)kth;
  478: 	aiov[0].iov_len = sizeof(struct ktr_header);
  479: 	auio.uio_resid = sizeof(struct ktr_header);
  480: 	auio.uio_iovcnt = 1;
  481: 	auio.uio_td = curthread;
  482: 	if (kth->ktr_len > 0) {
  483: 		auio.uio_iovcnt++;
  484: 		aiov[1].iov_base = kth->ktr_buf;
  485: 		aiov[1].iov_len = kth->ktr_len;
  486: 		auio.uio_resid += kth->ktr_len;
  487: 		if (uio != NULL)
  488: 			kth->ktr_len += uio->uio_resid;
  489: 	}
  490: 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
  491: 	(void)VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
  492: 	error = VOP_WRITE(vp, &auio, IO_UNIT | IO_APPEND, p->p_ucred);
  493: 	if (error == 0 && uio != NULL) {
  494: 		(void)VOP_LEASE(vp, td, p->p_ucred, LEASE_WRITE);
  495: 		error = VOP_WRITE(vp, uio, IO_UNIT | IO_APPEND, p->p_ucred);
  496: 	}
  497: 	VOP_UNLOCK(vp, 0, td);
  498: 	if (!error)
  499: 		return;
  500: 	/*
  501: 	 * If error encountered, give up tracing on this vnode.  XXX what
  502: 	 * happens to the loop if vrele() blocks?
  503: 	 */
  504: 	log(LOG_NOTICE, "ktrace write failed, errno %d, tracing stopped\n",
  505: 	    error);
  506: 	FOREACH_PROC_IN_SYSTEM(p) {
  507: 		if (p->p_tracep == vp) {
  508: 			p->p_tracep = NULL;
  509: 			p->p_traceflag = 0;
  510: 			vrele(vp);
  511: 		}
  512: 	}
  513: }
  514: 
  515: /*
  516:  * Return true if caller has permission to set the ktracing state
  517:  * of target.  Essentially, the target can't possess any
  518:  * more permissions than the caller.  KTRFAC_ROOT signifies that
  519:  * root previously set the tracing status on the target process, and
  520:  * so, only root may further change it.
  521:  *
  522:  * TODO: check groups.  use caller effective gid.
  523:  */
  524: static int
  525: ktrcanset(struct proc *callp, struct proc *targetp)
  526: {
  527: 	struct ucred *caller = callp->p_ucred;
  528: 	struct ucred *target = targetp->p_ucred;
  529: 
  530: 	if (!PRISON_CHECK(caller, target))
  531: 		return (0);
  532: 	if ((caller->cr_uid == target->cr_ruid &&
  533: 	     target->cr_ruid == target->cr_svuid &&
  534: 	     caller->cr_rgid == target->cr_rgid &&	/* XXX */
  535: 	     target->cr_rgid == target->cr_svgid &&
  536: 	     (targetp->p_traceflag & KTRFAC_ROOT) == 0 &&
  537: 	     (targetp->p_flag & P_SUGID) == 0) ||
  538: 	     caller->cr_uid == 0)
  539: 		return (1);
  540: 
  541: 	return (0);
  542: }
  543: 
  544: #endif /* KTRACE */