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      1 /*	$NetBSD: kern_ktrace_vfs.c,v 1.5 2026/01/04 01:35:33 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Andrew Doran.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * Copyright (c) 1989, 1993
     34  *	The Regents of the University of California.  All rights reserved.
     35  *
     36  * Redistribution and use in source and binary forms, with or without
     37  * modification, are permitted provided that the following conditions
     38  * are met:
     39  * 1. Redistributions of source code must retain the above copyright
     40  *    notice, this list of conditions and the following disclaimer.
     41  * 2. Redistributions in binary form must reproduce the above copyright
     42  *    notice, this list of conditions and the following disclaimer in the
     43  *    documentation and/or other materials provided with the distribution.
     44  * 3. Neither the name of the University nor the names of its contributors
     45  *    may be used to endorse or promote products derived from this software
     46  *    without specific prior written permission.
     47  *
     48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     58  * SUCH DAMAGE.
     59  *
     60  *	@(#)kern_ktrace.c	8.5 (Berkeley) 5/14/95
     61  */
     62 
     63 #include <sys/cdefs.h>
     64 __KERNEL_RCSID(0, "$NetBSD: kern_ktrace_vfs.c,v 1.5 2026/01/04 01:35:33 riastradh Exp $");
     65 
     66 #include <sys/param.h>
     67 
     68 #include <sys/file.h>
     69 #include <sys/filedesc.h>
     70 #include <sys/kauth.h>
     71 #include <sys/kernel.h>
     72 #include <sys/ktrace.h>
     73 #include <sys/mount.h>
     74 #include <sys/namei.h>
     75 #include <sys/sdt.h>
     76 #include <sys/syscallargs.h>
     77 #include <sys/systm.h>
     78 #include <sys/vnode.h>
     79 
     80 /*
     81  * ktrace system call, the part of the ktrace framework that
     82  * explicitly interacts with VFS
     83  */
     84 /* ARGSUSED */
     85 int
     86 sys_ktrace(struct lwp *l, const struct sys_ktrace_args *uap, register_t *retval)
     87 {
     88 	/* {
     89 		syscallarg(const char *) fname;
     90 		syscallarg(int) ops;
     91 		syscallarg(int) facs;
     92 		syscallarg(int) pid;
     93 	} */
     94 	struct vnode *vp = NULL;
     95 	file_t *fp = NULL;
     96 	struct pathbuf *pb;
     97 	int error = 0;
     98 	int fd;
     99 
    100 	if (ktrenter(l))
    101 		return SET_ERROR(EAGAIN);
    102 
    103 	if (KTROP(SCARG(uap, ops)) != KTROP_CLEAR) {
    104 		/*
    105 		 * an operation which requires a file argument.
    106 		 */
    107 		error = pathbuf_copyin(SCARG(uap, fname), &pb);
    108 		if (error) {
    109 			ktrexit(l);
    110 			return (error);
    111 		}
    112 		error = vn_open(NULL, pb, 0, FREAD|FWRITE, 0, &vp, NULL, NULL);
    113 		if (error != 0) {
    114 			pathbuf_destroy(pb);
    115 			ktrexit(l);
    116 			return (error);
    117 		}
    118 		pathbuf_destroy(pb);
    119 		VOP_UNLOCK(vp);
    120 		if (vp->v_type != VREG) {
    121 			vn_close(vp, FREAD|FWRITE, l->l_cred);
    122 			ktrexit(l);
    123 			return SET_ERROR(EACCES);
    124 		}
    125 		/*
    126 		 * This uses up a file descriptor slot in the
    127 		 * tracing process for the duration of this syscall.
    128 		 * This is not expected to be a problem.
    129 		 */
    130 		if ((error = fd_allocfile(&fp, &fd)) != 0) {
    131 			vn_close(vp, FWRITE, l->l_cred);
    132 			ktrexit(l);
    133 			return error;
    134 		}
    135 		fp->f_flag = FWRITE;
    136 		fp->f_type = DTYPE_VNODE;
    137 		fp->f_ops = &vnops;
    138 		fp->f_vnode = vp;
    139 		vp = NULL;
    140 	}
    141 	error = ktrace_common(l, SCARG(uap, ops), SCARG(uap, facs),
    142 	    SCARG(uap, pid), &fp);
    143 	if (KTROP(SCARG(uap, ops)) != KTROP_CLEAR)
    144 		fd_abort(curproc, fp, fd);
    145 	return (error);
    146 }
    147