sysfs.h revision 253449 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice unmodified, this list of conditions, and the following
12 *    disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef	_LINUX_SYSFS_H_
30#define	_LINUX_SYSFS_H_
31
32#include <sys/sysctl.h>
33
34struct attribute {
35	const char 	*name;
36	struct module	*owner;
37	mode_t		mode;
38};
39
40struct sysfs_ops {
41	ssize_t (*show)(struct kobject *, struct attribute *, char *);
42	ssize_t (*store)(struct kobject *, struct attribute *, const char *,
43	    size_t);
44};
45
46struct attribute_group {
47	const char		*name;
48	mode_t                  (*is_visible)(struct kobject *,
49				    struct attribute *, int);
50	struct attribute	**attrs;
51};
52
53#define	__ATTR(_name, _mode, _show, _store) {				\
54	.attr = { .name = __stringify(_name), .mode = _mode },		\
55        .show = _show, .store  = _store,				\
56}
57
58#define	__ATTR_RO(_name) {						\
59	.attr = { .name = __stringify(_name), .mode = 0444 },		\
60	.show   = _name##_show,						\
61}
62
63#define	__ATTR_NULL	{ .attr = { .name = NULL } }
64
65/*
66 * Handle our generic '\0' terminated 'C' string.
67 * Two cases:
68 *      a variable string:  point arg1 at it, arg2 is max length.
69 *      a constant string:  point arg1 at it, arg2 is zero.
70 */
71
72static inline int
73sysctl_handle_attr(SYSCTL_HANDLER_ARGS)
74{
75	struct kobject *kobj;
76	struct attribute *attr;
77	const struct sysfs_ops *ops;
78	char *buf;
79	int error;
80	ssize_t len;
81
82	kobj = arg1;
83	attr = (struct attribute *)arg2;
84	if (kobj->ktype == NULL || kobj->ktype->sysfs_ops == NULL)
85		return (ENODEV);
86	buf = (char *)get_zeroed_page(GFP_KERNEL);
87	if (buf == NULL)
88		return (ENOMEM);
89	ops = kobj->ktype->sysfs_ops;
90	if (ops->show) {
91		len = ops->show(kobj, attr, buf);
92		/*
93		 * It's valid to not have a 'show' so just return an
94		 * empty string.
95	 	 */
96		if (len < 0) {
97			error = -len;
98			if (error != EIO)
99				goto out;
100		}
101
102		/* Trim trailing newline. */
103		len--;
104		buf[len] = '\0';
105	}
106
107	/* Leave one trailing byte to append a newline. */
108	error = sysctl_handle_string(oidp, buf, PAGE_SIZE - 1, req);
109	if (error != 0 || req->newptr == NULL || ops->store == NULL)
110		goto out;
111	len = strlcat(buf, "\n", PAGE_SIZE);
112	KASSERT(len < PAGE_SIZE, ("new attribute truncated"));
113	len = ops->store(kobj, attr, buf, len);
114	if (len < 0)
115		error = -len;
116out:
117	free_page((unsigned long)buf);
118
119	return (error);
120}
121
122static inline int
123sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
124{
125
126	sysctl_add_oid(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
127	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
128	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
129
130	return (0);
131}
132
133static inline void
134sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
135{
136
137	if (kobj->oidp)
138		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
139}
140
141static inline void
142sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
143{
144
145	if (kobj->oidp)
146		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
147}
148
149static inline int
150sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
151{
152	struct attribute **attr;
153	struct sysctl_oid *oidp;
154
155	oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
156	    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
157	for (attr = grp->attrs; *attr != NULL; attr++) {
158		sysctl_add_oid(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
159		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
160		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
161	}
162
163	return (0);
164}
165
166static inline int
167sysfs_create_dir(struct kobject *kobj)
168{
169
170	kobj->oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
171	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
172
173        return (0);
174}
175
176static inline void
177sysfs_remove_dir(struct kobject *kobj)
178{
179
180	if (kobj->oidp == NULL)
181		return;
182	sysctl_remove_oid(kobj->oidp, 1, 1);
183}
184
185#endif	/* _LINUX_SYSFS_H_ */
186