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 /*
23 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */
28 /* All Rights Reserved */
29
30 /*
31 * Portions of this source code were derived from Berkeley 4.3 BSD
32 * under license from the Regents of the University of California.
33 */
34
35 #include <sys/param.h>
36 #include <sys/isa_defs.h>
37 #include <sys/types.h>
38 #include <sys/sysmacros.h>
39 #include <sys/cred.h>
40 #include <sys/systm.h>
41 #include <sys/errno.h>
42 #include <sys/pathname.h>
43 #include <sys/vnode.h>
44 #include <sys/vfs.h>
45 #include <sys/file.h>
46 #include <sys/uio.h>
47 #include <sys/debug.h>
48 #include <fs/fs_subr.h>
49
50 /*
51 * Common code for pathconf(), fpathconf() system calls
52 */
53 static long
cpathconf(register vnode_t * vp,int cmd,struct cred * cr)54 cpathconf(register vnode_t *vp, int cmd, struct cred *cr)
55 {
56 struct statvfs64 sb;
57 int error;
58 ulong_t val;
59
60 switch (cmd) {
61 case _PC_2_SYMLINKS:
62 if (error = VOP_PATHCONF(vp, _PC_SYMLINK_MAX, &val, cr, NULL))
63 return ((long)set_errno(error));
64 return ((long)(val > 0));
65
66 case _PC_ALLOC_SIZE_MIN:
67 case _PC_REC_INCR_XFER_SIZE:
68 case _PC_REC_MAX_XFER_SIZE:
69 case _PC_REC_MIN_XFER_SIZE:
70 case _PC_REC_XFER_ALIGN:
71 if ((error = VFS_STATVFS(vp->v_vfsp, &sb)) != 0)
72 return ((long)set_errno(error));
73
74 /*
75 * There is generally no harm in doing larger transfers, but
76 * there's a point of diminishing returns. With 1MB transfers,
77 * even if they're random, you get very close to platter speed.
78 * Se we return 1MB as the maximum transfer size.
79 */
80 if (cmd == _PC_REC_MAX_XFER_SIZE)
81 return ((long)MAX(sb.f_bsize, 1UL << 20));
82
83 /*
84 * By definition, f_frsize is the smallest filesystem block.
85 * However, _PC_ALLOC_SIZE_MIN is intended to define the
86 * threshold for direct I/O. This implies two requirements:
87 * the VM and I/O subsystems must be able to create mappings
88 * for DMA, which requires at least page alignment; and the
89 * filesystem must avoid read/modify/write, which generally
90 * requires multiples of its 'preferred' blocksize, f_bsize.
91 *
92 * PAGESIZE alignment is sufficient for DMA and block copy.
93 * Rounding up to the filesystem 'preferred' blocksize
94 * works just as well.
95 *
96 * All together, this means that the remaining parameters
97 * map into the same value.
98 */
99 return ((long)MAX(sb.f_bsize, PAGESIZE));
100
101 case _PC_ASYNC_IO:
102 return (1l);
103
104 case _PC_PRIO_IO:
105 return ((long)set_errno(EINVAL));
106
107 case _PC_SYNC_IO:
108 if (!(error = VOP_FSYNC(vp, FSYNC, cr, NULL)))
109 return (1l);
110 return ((long)set_errno(error));
111
112 case _PC_XATTR_ENABLED:
113 return ((vp->v_vfsp->vfs_flag & VFS_XATTR) ? 1 : 0);
114
115 default:
116 if (error = VOP_PATHCONF(vp, cmd, &val, cr, NULL))
117 return ((long)set_errno(error));
118 return (val);
119 }
120 /* NOTREACHED */
121 }
122
123 /* fpathconf/pathconf interfaces */
124
125 long
fpathconf(int fdes,int name)126 fpathconf(int fdes, int name)
127 {
128 file_t *fp;
129 long retval;
130
131 if ((fp = getf(fdes)) == NULL)
132 return (set_errno(EBADF));
133 retval = cpathconf(fp->f_vnode, name, fp->f_cred);
134 releasef(fdes);
135 return (retval);
136 }
137
138 long
pathconf(char * fname,int name)139 pathconf(char *fname, int name)
140 {
141 vnode_t *vp;
142 long retval;
143 int error;
144 int estale_retry = 0;
145
146 lookup:
147 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) {
148 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++))
149 goto lookup;
150 return ((long)set_errno(error));
151 }
152
153 retval = cpathconf(vp, name, CRED());
154 VN_RELE(vp);
155 return (retval);
156 }
157