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 #pragma ident "%Z%%M% %I% %E% SMI"
36
37 #include <sys/param.h>
38 #include <sys/isa_defs.h>
39 #include <sys/types.h>
40 #include <sys/sysmacros.h>
41 #include <sys/cred.h>
42 #include <sys/systm.h>
43 #include <sys/errno.h>
44 #include <sys/pathname.h>
45 #include <sys/vnode.h>
46 #include <sys/vfs.h>
47 #include <sys/file.h>
48 #include <sys/uio.h>
49 #include <sys/debug.h>
50 #include <fs/fs_subr.h>
51
52 /*
53 * Common code for pathconf(), fpathconf() system calls
54 */
55 static long
cpathconf(register vnode_t * vp,int cmd,struct cred * cr)56 cpathconf(register vnode_t *vp, int cmd, struct cred *cr)
57 {
58 struct statvfs64 sb;
59 int error;
60 ulong_t val;
61
62 switch (cmd) {
63 case _PC_2_SYMLINKS:
64 if (error = VOP_PATHCONF(vp, _PC_SYMLINK_MAX, &val, cr, NULL))
65 return ((long)set_errno(error));
66 return ((long)(val > 0));
67
68 case _PC_ALLOC_SIZE_MIN:
69 case _PC_REC_INCR_XFER_SIZE:
70 case _PC_REC_MAX_XFER_SIZE:
71 case _PC_REC_MIN_XFER_SIZE:
72 case _PC_REC_XFER_ALIGN:
73 if ((error = VFS_STATVFS(vp->v_vfsp, &sb)) != 0)
74 return ((long)set_errno(error));
75
76 /*
77 * There is generally no harm in doing larger transfers, but
78 * there's a point of diminishing returns. With 1MB transfers,
79 * even if they're random, you get very close to platter speed.
80 * Se we return 1MB as the maximum transfer size.
81 */
82 if (cmd == _PC_REC_MAX_XFER_SIZE)
83 return ((long)MAX(sb.f_bsize, 1UL << 20));
84
85 /*
86 * By definition, f_frsize is the smallest filesystem block.
87 * However, _PC_ALLOC_SIZE_MIN is intended to define the
88 * threshold for direct I/O. This implies two requirements:
89 * the VM and I/O subsystems must be able to create mappings
90 * for DMA, which requires at least page alignment; and the
91 * filesystem must avoid read/modify/write, which generally
92 * requires multiples of its 'preferred' blocksize, f_bsize.
93 *
94 * PAGESIZE alignment is sufficient for DMA and block copy.
95 * Rounding up to the filesystem 'preferred' blocksize
96 * works just as well.
97 *
98 * All together, this means that the remaining parameters
99 * map into the same value.
100 */
101 return ((long)MAX(sb.f_bsize, PAGESIZE));
102
103 case _PC_ASYNC_IO:
104 return (1l);
105
106 case _PC_PRIO_IO:
107 return ((long)set_errno(EINVAL));
108
109 case _PC_SYNC_IO:
110 if (!(error = VOP_FSYNC(vp, FSYNC, cr, NULL)))
111 return (1l);
112 return ((long)set_errno(error));
113
114 case _PC_XATTR_ENABLED:
115 return ((vp->v_vfsp->vfs_flag & VFS_XATTR) ? 1 : 0);
116
117 default:
118 if (error = VOP_PATHCONF(vp, cmd, &val, cr, NULL))
119 return ((long)set_errno(error));
120 return (val);
121 }
122 /* NOTREACHED */
123 }
124
125 /* fpathconf/pathconf interfaces */
126
127 long
fpathconf(int fdes,int name)128 fpathconf(int fdes, int name)
129 {
130 file_t *fp;
131 long retval;
132
133 if ((fp = getf(fdes)) == NULL)
134 return (set_errno(EBADF));
135 retval = cpathconf(fp->f_vnode, name, fp->f_cred);
136 releasef(fdes);
137 return (retval);
138 }
139
140 long
pathconf(char * fname,int name)141 pathconf(char *fname, int name)
142 {
143 vnode_t *vp;
144 long retval;
145 int error;
146 int estale_retry = 0;
147
148 lookup:
149 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) {
150 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++))
151 goto lookup;
152 return ((long)set_errno(error));
153 }
154
155 retval = cpathconf(vp, name, CRED());
156 VN_RELE(vp);
157 return (retval);
158 }
159