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      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_kproto.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 ((rc = smb_ofile_seek(sr->fid_ofile, mode, off, &off_ret)) != 0) {
    113 		if (rc == EINVAL) {
    114 			smbsr_error(sr, 0, ERRDOS, ERRbadfunc);
    115 			return (SDRC_ERROR);
    116 		} else {
    117 			smbsr_error(sr, 0, ERRSRV, ERRerror);
    118 			return (SDRC_ERROR);
    119 		}
    120 	}
    121 
    122 	if (smbsr_encode_result(sr, 2, 0, "blw", 2, off_ret, 0))
    123 		return (SDRC_ERROR);
    124 
    125 	return (SDRC_SUCCESS);
    126 }
    127