xref: /titanic_51/usr/src/uts/common/fs/smbsrv/smb_seek.c (revision b6c3f7863936abeae522e48a13887dddeb691a45)
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 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
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_incl.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  */
82 smb_sdrc_t
83 smb_com_seek(struct smb_request *sr)
84 {
85 	ushort_t	mode;
86 	int32_t		off;
87 	uint32_t	off_ret;
88 	int		rc;
89 
90 	if (smbsr_decode_vwv(sr, "wwl", &sr->smb_fid, &mode, &off) != 0)
91 		return (SDRC_ERROR_REPLY);
92 
93 	sr->fid_ofile = smb_ofile_lookup_by_fid(sr->tid_tree, sr->smb_fid);
94 	if (sr->fid_ofile == NULL) {
95 		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
96 		return (SDRC_ERROR_REPLY);
97 	}
98 
99 	if (mode == SMB_SEEK_END)
100 		(void) smb_set_file_size(sr);
101 
102 	if ((rc = smb_ofile_seek(sr->fid_ofile, mode, off, &off_ret)) != 0) {
103 		if (rc == EINVAL) {
104 			smbsr_error(sr, 0, ERRDOS, ERRbadfunc);
105 			return (SDRC_ERROR_REPLY);
106 		} else {
107 			smbsr_error(sr, 0, ERRSRV, ERRerror);
108 			return (SDRC_ERROR_REPLY);
109 		}
110 	}
111 
112 	if (smbsr_encode_result(sr, 2, 0, "blw", 2, off_ret, 0))
113 		return (SDRC_ERROR_REPLY);
114 
115 	return (SDRC_NORMAL_REPLY);
116 }
117