1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  * Copyright (c) 2015, Joyent, Inc.  All rights reserved.
26  * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
27  */
28 
29 /*	Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T	*/
30 /*	  All Rights Reserved	*/
31 
32 /*
33  * Portions of this source code were derived from Berkeley 4.3 BSD
34  * under license from the Regents of the University of California.
35  */
36 
37 #include <sys/param.h>
38 #include <sys/types.h>
39 #include <sys/inttypes.h>
40 #include <sys/sysmacros.h>
41 #include <sys/cred.h>
42 #include <sys/user.h>
43 #include <sys/systm.h>
44 #include <sys/errno.h>
45 #include <sys/vnode.h>
46 #include <sys/file.h>
47 #include <sys/proc.h>
48 #include <sys/uio.h>
49 #include <sys/debug.h>
50 
51 #include <libfksmbfs.h>
52 
53 #define	set_errno(e) (-(e))
54 
55 ssize_t
56 fake_pread(vnode_t *vp, void *cbuf, size_t count, off_t offset)
57 {
58 	struct uio auio;
59 	struct iovec aiov;
60 	int fflag, ioflag, rwflag;
61 	ssize_t bcount;
62 	int error = 0;
63 	u_offset_t fileoff = (u_offset_t)(ulong_t)offset;
64 	const u_offset_t maxoff = MAXOFF32_T;
65 
66 	if ((bcount = (ssize_t)count) < 0)
67 		return (set_errno(EINVAL));
68 	fflag = FREAD;
69 
70 	rwflag = 0;
71 
72 	if (vp->v_type == VREG) {
73 
74 		if (bcount == 0)
75 			goto out;
76 
77 		/*
78 		 * Return EINVAL if an invalid offset comes to pread.
79 		 * Negative offset from user will cause this error.
80 		 */
81 
82 		if (fileoff > maxoff) {
83 			error = EINVAL;
84 			goto out;
85 		}
86 		/*
87 		 * Limit offset such that we don't read or write
88 		 * a file beyond the maximum offset representable in
89 		 * an off_t structure.
90 		 */
91 		if (fileoff + bcount > maxoff)
92 			bcount = (ssize_t)((offset_t)maxoff - fileoff);
93 	} else if (vp->v_type == VFIFO) {
94 		error = ESPIPE;
95 		goto out;
96 	}
97 
98 	aiov.iov_base = cbuf;
99 	aiov.iov_len = bcount;
100 	(void) VOP_RWLOCK(vp, rwflag, NULL);
101 	auio.uio_loffset = fileoff;
102 	auio.uio_iov = &aiov;
103 	auio.uio_iovcnt = 1;
104 	auio.uio_resid = bcount;
105 	auio.uio_segflg = UIO_USERSPACE;
106 	auio.uio_llimit = MAXOFFSET_T;
107 	auio.uio_fmode = fflag;
108 	auio.uio_extflg = UIO_COPY_CACHED;
109 
110 	ioflag = auio.uio_fmode & (FAPPEND|FSYNC|FDSYNC|FRSYNC);
111 
112 	/* If read sync is not asked for, filter sync flags */
113 	if ((ioflag & FRSYNC) == 0)
114 		ioflag &= ~(FSYNC|FDSYNC);
115 	error = VOP_READ(vp, &auio, ioflag, CRED(), NULL);
116 	bcount -= auio.uio_resid;
117 	VOP_RWUNLOCK(vp, rwflag, NULL);
118 
119 	if (error == EINTR && bcount != 0)
120 		error = 0;
121 out:
122 	if (error)
123 		return (set_errno(error));
124 	return (bcount);
125 }
126 
127 ssize_t
128 fake_pwrite(vnode_t *vp, void *cbuf, size_t count, off_t offset)
129 {
130 	struct uio auio;
131 	struct iovec aiov;
132 	int fflag, ioflag, rwflag;
133 	ssize_t bcount;
134 	int error = 0;
135 	u_offset_t fileoff = (u_offset_t)(ulong_t)offset;
136 	const u_offset_t maxoff = MAXOFF32_T;
137 
138 	if ((bcount = (ssize_t)count) < 0)
139 		return (set_errno(EINVAL));
140 	fflag = FREAD | FWRITE;
141 
142 	rwflag = 1;
143 
144 	if (vp->v_type == VREG) {
145 
146 		if (bcount == 0)
147 			goto out;
148 
149 		/*
150 		 * return EINVAL for offsets that cannot be
151 		 * represented in an off_t.
152 		 */
153 		if (fileoff > maxoff) {
154 			error = EINVAL;
155 			goto out;
156 		}
157 		/*
158 		 * Don't allow pwrite to cause file sizes to exceed
159 		 * maxoff.
160 		 */
161 		if (fileoff == maxoff) {
162 			error = EFBIG;
163 			goto out;
164 		}
165 		if (fileoff + count > maxoff)
166 			bcount = (ssize_t)((u_offset_t)maxoff - fileoff);
167 	} else if (vp->v_type == VFIFO) {
168 		error = ESPIPE;
169 		goto out;
170 	}
171 
172 	aiov.iov_base = cbuf;
173 	aiov.iov_len = bcount;
174 	(void) VOP_RWLOCK(vp, rwflag, NULL);
175 	auio.uio_loffset = fileoff;
176 	auio.uio_iov = &aiov;
177 	auio.uio_iovcnt = 1;
178 	auio.uio_resid = bcount;
179 	auio.uio_segflg = UIO_USERSPACE;
180 	auio.uio_llimit = MAXOFFSET_T;
181 	auio.uio_fmode = fflag;
182 	auio.uio_extflg = UIO_COPY_CACHED;
183 
184 	/*
185 	 * The SUSv4 POSIX specification states:
186 	 *	The pwrite() function shall be equivalent to write(), except
187 	 *	that it writes into a given position and does not change
188 	 *	the file offset (regardless of whether O_APPEND is set).
189 	 * To make this be true, we omit the FAPPEND flag from ioflag.
190 	 */
191 	ioflag = auio.uio_fmode & (FSYNC|FDSYNC|FRSYNC);
192 
193 	error = VOP_WRITE(vp, &auio, ioflag, CRED(), NULL);
194 	bcount -= auio.uio_resid;
195 	VOP_RWUNLOCK(vp, rwflag, NULL);
196 
197 	if (error == EINTR && bcount != 0)
198 		error = 0;
199 out:
200 	if (error)
201 		return (set_errno(error));
202 	return (bcount);
203 }
204