sysfs.h revision 290613 
1/*-
2 * Copyright (c) 2010 Isilon Systems, Inc.
3 * Copyright (c) 2010 iX Systems, Inc.
4 * Copyright (c) 2010 Panasas, Inc.
5 * Copyright (c) 2013, 2014 Mellanox Technologies, Ltd.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice unmodified, this list of conditions, and the following
13 *    disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * $FreeBSD: head/sys/compat/linuxkpi/common/include/linux/sysfs.h 290613 2015-11-09 16:50:42Z cem $
30 */
31#ifndef	_LINUX_SYSFS_H_
32#define	_LINUX_SYSFS_H_
33
34#include <sys/types.h>
35#include <sys/sysctl.h>
36#include <sys/errno.h>
37
38#include <linux/kobject.h>
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 *)(intptr_t)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			buf[0] = '\0';
101		} else if (len) {
102			len--;
103			if (len >= PAGE_SIZE)
104				len = PAGE_SIZE - 1;
105			/* Trim trailing newline. */
106			buf[len] = '\0';
107		}
108	}
109
110	/* Leave one trailing byte to append a newline. */
111	error = sysctl_handle_string(oidp, buf, PAGE_SIZE - 1, req);
112	if (error != 0 || req->newptr == NULL || ops->store == NULL)
113		goto out;
114	len = strlcat(buf, "\n", PAGE_SIZE);
115	KASSERT(len < PAGE_SIZE, ("new attribute truncated"));
116	len = ops->store(kobj, attr, buf, len);
117	if (len < 0)
118		error = -len;
119out:
120	free_page((unsigned long)buf);
121
122	return (error);
123}
124
125static inline int
126sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
127{
128
129	sysctl_add_oid(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
130	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
131	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
132
133	return (0);
134}
135
136static inline void
137sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
138{
139
140	if (kobj->oidp)
141		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
142}
143
144static inline void
145sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
146{
147
148	if (kobj->oidp)
149		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
150}
151
152static inline int
153sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
154{
155	struct attribute **attr;
156	struct sysctl_oid *oidp;
157
158	oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
159	    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
160	for (attr = grp->attrs; *attr != NULL; attr++) {
161		sysctl_add_oid(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
162		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
163		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
164	}
165
166	return (0);
167}
168
169static inline int
170sysfs_create_dir(struct kobject *kobj)
171{
172
173	kobj->oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
174	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
175
176        return (0);
177}
178
179static inline void
180sysfs_remove_dir(struct kobject *kobj)
181{
182
183	if (kobj->oidp == NULL)
184		return;
185	sysctl_remove_oid(kobj->oidp, 1, 1);
186}
187
188#define sysfs_attr_init(attr) do {} while(0)
189
190#endif	/* _LINUX_SYSFS_H_ */
191