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 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
23 * Use is subject to license terms.
24 *
25 * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
26 */
27
28/*
29 * The seek message is sent to set the current file pointer for FID.
30 * This request should generally only be used by clients wishing to
31 * find the size of a file, since all read and write requests include
32 * the read or write file position as part of the SMB. This request
33 * is inappropriate for large files, as the offsets specified are only
34 * 32 bits.
35 *
36 * The CIFS/1.0 (1996) spec contains the following incomplete statement:
37 *
38 * "A seek which results in an Offset which can not be expressed
39 *  in 32 bits returns the least significant."
40 *
41 * It would probably be a mistake to make an assumption about what this
42 * statement means. So, for now, we return an error if the resultant
43 * file offset is beyond the 32-bit limit.
44 */
45
46#include <smbsrv/smb_kproto.h>
47
48
49/*
50 * smb_com_seek
51 *
52 * Client Request                     Description
53 * ================================== =================================
54 * UCHAR WordCount;                   Count of parameter words = 4
55 * USHORT Fid;                        File handle
56 * USHORT Mode;                       Seek mode: 0, 1 or 2
57 * LONG Offset;                       Relative offset
58 * USHORT ByteCount;                  Count of data bytes = 0
59 *
60 * The starting point of the seek is set by Mode:
61 *
62 *      0  seek from start of file
63 *      1  seek from current current position
64 *      2  seek from end of file
65 *
66 * The "current position" reflects the offset plus data length specified in
67 * the previous read, write or seek request, and the pointer set by this
68 * command will be replaced by the offset specified in the next read, write
69 * or seek command.
70 *
71 * Server Response                    Description
72 * ================================== =================================
73 * UCHAR WordCount;                   Count of parameter words = 2
74 * ULONG Offset;                      Offset from start of file
75 * USHORT ByteCount;                  Count of data bytes = 0
76 *
77 * The response returns the new file pointer in Offset, which is expressed
78 * as the offset from the start of the file, and may be beyond the current
79 * end of file. An attempt to seek before the start of the file sets the
80 * current file pointer to the start of the file.
81 */
82smb_sdrc_t
83smb_pre_seek(smb_request_t *sr)
84{
85	DTRACE_SMB_START(op__Seek, smb_request_t *, sr);
86	return (SDRC_SUCCESS);
87}
88
89void
90smb_post_seek(smb_request_t *sr)
91{
92	DTRACE_SMB_DONE(op__Seek, smb_request_t *, sr);
93}
94
95smb_sdrc_t
96smb_com_seek(smb_request_t *sr)
97{
98	ushort_t	mode;
99	int32_t		off;
100	uint32_t	off_ret;
101	int		rc;
102
103	if (smbsr_decode_vwv(sr, "wwl", &sr->smb_fid, &mode, &off) != 0)
104		return (SDRC_ERROR);
105
106	smbsr_lookup_file(sr);
107	if (sr->fid_ofile == NULL) {
108		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
109		return (SDRC_ERROR);
110	}
111
112	sr->user_cr = smb_ofile_getcred(sr->fid_ofile);
113
114	if ((rc = smb_ofile_seek(sr->fid_ofile, mode, off, &off_ret)) != 0) {
115		if (rc == EINVAL) {
116			smbsr_error(sr, 0, ERRDOS, ERRbadfunc);
117			return (SDRC_ERROR);
118		} else {
119			smbsr_error(sr, 0, ERRSRV, ERRerror);
120			return (SDRC_ERROR);
121		}
122	}
123
124	if (smbsr_encode_result(sr, 2, 0, "blw", 2, off_ret, 0))
125		return (SDRC_ERROR);
126
127	return (SDRC_SUCCESS);
128}
129