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, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22 /*
23 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #pragma ident "%Z%%M% %I% %E% SMI"
28
29 #include <sys/types.h>
30 #include <sys/errno.h>
31 #include <sys/proc.h>
32 #include <sys/procfs.h>
33 #include <sys/sysmacros.h>
34 #include <sys/uio.h>
35 #include <sys/cmn_err.h>
36
37 #if defined(__sparc)
38 #include <sys/stack.h>
39 #endif
40
41 #define STACK_BUF_SIZE 64 /* power of 2 */
42
43 int
prusrio(proc_t * p,enum uio_rw rw,struct uio * uiop,int old)44 prusrio(proc_t *p, enum uio_rw rw, struct uio *uiop, int old)
45 {
46 /* longlong-aligned short buffer */
47 longlong_t buffer[STACK_BUF_SIZE / sizeof (longlong_t)];
48 int error = 0;
49 void *bp;
50 int allocated;
51 ssize_t total = uiop->uio_resid;
52 uintptr_t addr;
53 size_t len;
54
55 /* for short reads/writes, use the on-stack buffer */
56 if (uiop->uio_resid <= STACK_BUF_SIZE) {
57 bp = buffer;
58 allocated = 0;
59 } else {
60 bp = kmem_alloc(PAGESIZE, KM_SLEEP);
61 allocated = 1;
62 }
63
64 #if defined(__sparc)
65 if (p == curproc)
66 (void) flush_user_windows_to_stack(NULL);
67 #endif
68
69 switch (rw) {
70 case UIO_READ:
71 while (uiop->uio_resid != 0) {
72 addr = uiop->uio_offset;
73 len = MIN(uiop->uio_resid,
74 PAGESIZE - (addr & PAGEOFFSET));
75
76 if ((error = uread(p, bp, len, addr)) != 0 ||
77 (error = uiomove(bp, len, UIO_READ, uiop)) != 0)
78 break;
79 }
80
81 /*
82 * ENXIO indicates that a page didn't exist. If the I/O was
83 * truncated, return success; otherwise convert the error into
84 * EIO. When obeying new /proc semantics, we don't return an
85 * error for a read that begins at an invalid address.
86 */
87 if (error == ENXIO) {
88 if (total != uiop->uio_resid || !old)
89 error = 0;
90 else
91 error = EIO;
92 }
93 break;
94 case UIO_WRITE:
95 while (uiop->uio_resid != 0) {
96 addr = uiop->uio_offset;
97 len = MIN(uiop->uio_resid,
98 PAGESIZE - (addr & PAGEOFFSET));
99
100 if ((error = uiomove(bp, len, UIO_WRITE, uiop)) != 0)
101 break;
102 if ((error = uwrite(p, bp, len, addr)) != 0) {
103 uiop->uio_resid += len;
104 uiop->uio_loffset -= len;
105 break;
106 }
107 }
108
109 /*
110 * ENXIO indicates that a page didn't exist. If the I/O was
111 * truncated, return success; otherwise convert the error
112 * into EIO.
113 */
114 if (error == ENXIO) {
115 if (total != uiop->uio_resid)
116 error = 0;
117 else
118 error = EIO;
119 }
120 break;
121 default:
122 panic("prusrio: rw=%d neither UIO_READ not UIO_WRITE", rw);
123 /*NOTREACHED*/
124 }
125
126 if (allocated)
127 kmem_free(bp, PAGESIZE);
128
129 return (error);
130 }
131