xref: /titanic_41/usr/src/uts/common/fs/smbsrv/smb_seek.c (revision e802abbda8c322f24d47835734f4a793ef15ddc8)
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 
26 /*
27  * The seek message is sent to set the current file pointer for FID.
28  * This request should generally only be used by clients wishing to
29  * find the size of a file, since all read and write requests include
30  * the read or write file position as part of the SMB. This request
31  * is inappropriate for large files, as the offsets specified are only
32  * 32 bits.
33  *
34  * The CIFS/1.0 (1996) spec contains the following incomplete statement:
35  *
36  * "A seek which results in an Offset which can not be expressed
37  *  in 32 bits returns the least significant."
38  *
39  * It would probably be a mistake to make an assumption about what this
40  * statement means. So, for now, we return an error if the resultant
41  * file offset is beyond the 32-bit limit.
42  */
43 
44 #include <smbsrv/smb_incl.h>
45 
46 
47 /*
48  * smb_com_seek
49  *
50  * Client Request                     Description
51  * ================================== =================================
52  * UCHAR WordCount;                   Count of parameter words = 4
53  * USHORT Fid;                        File handle
54  * USHORT Mode;                       Seek mode: 0, 1 or 2
55  * LONG Offset;                       Relative offset
56  * USHORT ByteCount;                  Count of data bytes = 0
57  *
58  * The starting point of the seek is set by Mode:
59  *
60  *      0  seek from start of file
61  *      1  seek from current current position
62  *      2  seek from end of file
63  *
64  * The "current position" reflects the offset plus data length specified in
65  * the previous read, write or seek request, and the pointer set by this
66  * command will be replaced by the offset specified in the next read, write
67  * or seek command.
68  *
69  * Server Response                    Description
70  * ================================== =================================
71  * UCHAR WordCount;                   Count of parameter words = 2
72  * ULONG Offset;                      Offset from start of file
73  * USHORT ByteCount;                  Count of data bytes = 0
74  *
75  * The response returns the new file pointer in Offset, which is expressed
76  * as the offset from the start of the file, and may be beyond the current
77  * end of file. An attempt to seek before the start of the file sets the
78  * current file pointer to the start of the file.
79  */
80 smb_sdrc_t
81 smb_pre_seek(smb_request_t *sr)
82 {
83 	DTRACE_SMB_1(op__Seek__start, smb_request_t *, sr);
84 	return (SDRC_SUCCESS);
85 }
86 
87 void
88 smb_post_seek(smb_request_t *sr)
89 {
90 	DTRACE_SMB_1(op__Seek__done, smb_request_t *, sr);
91 }
92 
93 smb_sdrc_t
94 smb_com_seek(smb_request_t *sr)
95 {
96 	ushort_t	mode;
97 	int32_t		off;
98 	uint32_t	off_ret;
99 	int		rc;
100 
101 	if (smbsr_decode_vwv(sr, "wwl", &sr->smb_fid, &mode, &off) != 0)
102 		return (SDRC_ERROR);
103 
104 	smbsr_lookup_file(sr);
105 	if (sr->fid_ofile == NULL) {
106 		smbsr_error(sr, NT_STATUS_INVALID_HANDLE, ERRDOS, ERRbadfid);
107 		return (SDRC_ERROR);
108 	}
109 
110 	sr->user_cr = smb_ofile_getcred(sr->fid_ofile);
111 
112 	if (mode == SMB_SEEK_END)
113 		(void) smb_set_file_size(sr, sr->fid_ofile->f_node);
114 
115 	if ((rc = smb_ofile_seek(sr->fid_ofile, mode, off, &off_ret)) != 0) {
116 		if (rc == EINVAL) {
117 			smbsr_error(sr, 0, ERRDOS, ERRbadfunc);
118 			return (SDRC_ERROR);
119 		} else {
120 			smbsr_error(sr, 0, ERRSRV, ERRerror);
121 			return (SDRC_ERROR);
122 		}
123 	}
124 
125 	if (smbsr_encode_result(sr, 2, 0, "blw", 2, off_ret, 0))
126 		return (SDRC_ERROR);
127 
128 	return (SDRC_SUCCESS);
129 }
130