xref: /illumos-gate/usr/src/uts/common/fs/smbsrv/smb2_read.c (revision 13b136d3061155363c62c9f6568d25b8b27da8f6)
1 /*
2  * This file and its contents are supplied under the terms of the
3  * Common Development and Distribution License ("CDDL"), version 1.0.
4  * You may only use this file in accordance with the terms of version
5  * 1.0 of the CDDL.
6  *
7  * A full copy of the text of the CDDL should have accompanied this
8  * source.  A copy of the CDDL is also available via the Internet at
9  * http://www.illumos.org/license/CDDL.
10  */
11 
12 /*
13  * Copyright 2019 Nexenta Systems, Inc.  All rights reserved.
14  */
15 
16 /*
17  * Dispatch function for SMB2_READ
18  */
19 
20 #include <smbsrv/smb2_kproto.h>
21 #include <smbsrv/smb_fsops.h>
22 
23 extern boolean_t smb_allow_unbuffered;
24 
25 smb_sdrc_t
26 smb2_read(smb_request_t *sr)
27 {
28 	smb_rw_param_t *param = NULL;
29 	smb_ofile_t *of = NULL;
30 	smb_vdb_t *vdb = NULL;
31 	struct mbuf *m = NULL;
32 	uint16_t StructSize;
33 	uint8_t Padding;
34 	uint8_t Flags;
35 	uint8_t DataOff;
36 	uint32_t Length;
37 	uint64_t Offset;
38 	smb2fid_t smb2fid;
39 	uint32_t MinCount;
40 	uint32_t Channel;
41 	uint32_t Remaining;
42 	uint16_t ChanInfoOffset;
43 	uint16_t ChanInfoLength;
44 	uint32_t XferCount;
45 	uint32_t status;
46 	int rc = 0;
47 	boolean_t unbuffered = B_FALSE;
48 	int ioflag = 0;
49 
50 	/*
51 	 * SMB2 Read request
52 	 */
53 	rc = smb_mbc_decodef(
54 	    &sr->smb_data,
55 	    "wbblqqqlllww",
56 	    &StructSize,		/* w */
57 	    &Padding,			/* b */
58 	    &Flags,			/* b */
59 	    &Length,			/* l */
60 	    &Offset,			/* q */
61 	    &smb2fid.persistent,	/* q */
62 	    &smb2fid.temporal,		/* q */
63 	    &MinCount,			/* l */
64 	    &Channel,			/* l */
65 	    &Remaining,			/* l */
66 	    &ChanInfoOffset,		/* w */
67 	    &ChanInfoLength);		/* w */
68 	if (rc)
69 		return (SDRC_ERROR);
70 	if (StructSize != 49)
71 		return (SDRC_ERROR);
72 
73 	/*
74 	 * Setup an smb_rw_param_t which contains the VDB we need.
75 	 * This is automatically free'd.
76 	 */
77 	param = smb_srm_zalloc(sr, sizeof (*param));
78 	param->rw_offset = Offset;
79 	param->rw_count = Length;
80 	/* Note that the dtrace provider uses sr->arg.rw */
81 	sr->arg.rw = param;
82 
83 	/*
84 	 * Want FID lookup before the start probe.
85 	 */
86 	status = smb2sr_lookup_fid(sr, &smb2fid);
87 	of = sr->fid_ofile;
88 
89 	DTRACE_SMB2_START(op__Read, smb_request_t *, sr); /* arg.rw */
90 
91 	if (status)
92 		goto errout; /* Bad FID */
93 
94 	if (Length > smb2_max_rwsize) {
95 		status = NT_STATUS_INVALID_PARAMETER;
96 		goto errout;
97 	}
98 	if (MinCount > Length)
99 		MinCount = Length;
100 
101 	vdb = &param->rw_vdb;
102 	vdb->vdb_tag = 0;
103 	vdb->vdb_uio.uio_iov = &vdb->vdb_iovec[0];
104 	vdb->vdb_uio.uio_iovcnt = MAX_IOVEC;
105 	vdb->vdb_uio.uio_resid = Length;
106 	vdb->vdb_uio.uio_loffset = (offset_t)Offset;
107 	vdb->vdb_uio.uio_segflg = UIO_SYSSPACE;
108 	vdb->vdb_uio.uio_extflg = UIO_COPY_DEFAULT;
109 
110 	sr->raw_data.max_bytes = Length;
111 	m = smb_mbuf_allocate(&vdb->vdb_uio);
112 
113 	/*
114 	 * Unbuffered refers to the MS-FSA Read argument by the same name.
115 	 * It indicates that the cache for this range should be flushed to disk,
116 	 * and data read directly from disk, bypassing the cache.
117 	 * We don't allow that degree of cache management.
118 	 * Translate this directly as FRSYNC,
119 	 * which should at least flush the cache first.
120 	 */
121 
122 	if (smb_allow_unbuffered &&
123 	    (Flags & SMB2_READFLAG_READ_UNBUFFERED) != 0) {
124 		unbuffered = B_TRUE;
125 		ioflag = FRSYNC;
126 	}
127 
128 	switch (of->f_tree->t_res_type & STYPE_MASK) {
129 	case STYPE_DISKTREE:
130 		if (!smb_node_is_dir(of->f_node)) {
131 			/* Check for conflicting locks. */
132 			rc = smb_lock_range_access(sr, of->f_node,
133 			    Offset, Length, B_FALSE);
134 			if (rc) {
135 				rc = ERANGE;
136 				break;
137 			}
138 		}
139 		rc = smb_fsop_read(sr, of->f_cr, of->f_node, of,
140 		    &vdb->vdb_uio, ioflag);
141 		break;
142 	case STYPE_IPC:
143 		if (unbuffered)
144 			rc = EINVAL;
145 		else
146 			rc = smb_opipe_read(sr, &vdb->vdb_uio);
147 		break;
148 	default:
149 	case STYPE_PRINTQ:
150 		rc = EACCES;
151 		break;
152 	}
153 	status = smb_errno2status(rc);
154 
155 	/* How much data we moved. */
156 	XferCount = Length - vdb->vdb_uio.uio_resid;
157 
158 	sr->raw_data.max_bytes = XferCount;
159 	smb_mbuf_trim(m, XferCount);
160 	MBC_ATTACH_MBUF(&sr->raw_data, m);
161 
162 	/*
163 	 * Checking the error return _after_ dealing with
164 	 * the returned data so that if m was allocated,
165 	 * it will be free'd via sr->raw_data cleanup.
166 	 */
167 errout:
168 	sr->smb2_status = status;
169 	DTRACE_SMB2_DONE(op__Read, smb_request_t *, sr); /* arg.rw */
170 	if (status) {
171 		smb2sr_put_error(sr, status);
172 		return (SDRC_SUCCESS);
173 	}
174 
175 	/*
176 	 * SMB2 Read reply
177 	 */
178 	DataOff = SMB2_HDR_SIZE + 16;
179 	rc = smb_mbc_encodef(
180 	    &sr->reply,
181 	    "wb.lllC",
182 	    17,	/* StructSize */	/* w */
183 	    DataOff,			/* b. */
184 	    XferCount,			/* l */
185 	    0, /* DataRemaining */	/* l */
186 	    0, /* reserved */		/* l */
187 	    &sr->raw_data);		/* C */
188 	if (rc) {
189 		sr->smb2_status = NT_STATUS_INTERNAL_ERROR;
190 		return (SDRC_ERROR);
191 	}
192 
193 	mutex_enter(&of->f_mutex);
194 	of->f_seek_pos = Offset + XferCount;
195 	mutex_exit(&of->f_mutex);
196 
197 	return (SDRC_SUCCESS);
198 }
199