sysfs.h revision 328653 
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: stable/11/sys/compat/linuxkpi/common/include/linux/sysfs.h 328653 2018-02-01 13:01:44Z hselasky $
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#define	__ATTR_RO(_name)	__ATTR(_name, 0444, _name##_show, NULL)
58#define	__ATTR_WO(_name)	__ATTR(_name, 0200, NULL, _name##_store)
59#define	__ATTR_RW(_name)	__ATTR(_name, 0644, _name##_show, _name##_store)
60
61#define	__ATTR_NULL	{ .attr = { .name = NULL } }
62
63#define	ATTRIBUTE_GROUPS(_name)						\
64	static struct attribute_group _name##_group = {			\
65		.attrs = _name##_attrs,					\
66	};								\
67	static struct attribute_group *_name##_groups[] = {		\
68		&_name##_group,						\
69		NULL,							\
70	};
71
72/*
73 * Handle our generic '\0' terminated 'C' string.
74 * Two cases:
75 *      a variable string:  point arg1 at it, arg2 is max length.
76 *      a constant string:  point arg1 at it, arg2 is zero.
77 */
78
79static inline int
80sysctl_handle_attr(SYSCTL_HANDLER_ARGS)
81{
82	struct kobject *kobj;
83	struct attribute *attr;
84	const struct sysfs_ops *ops;
85	char *buf;
86	int error;
87	ssize_t len;
88
89	kobj = arg1;
90	attr = (struct attribute *)(intptr_t)arg2;
91	if (kobj->ktype == NULL || kobj->ktype->sysfs_ops == NULL)
92		return (ENODEV);
93	buf = (char *)get_zeroed_page(GFP_KERNEL);
94	if (buf == NULL)
95		return (ENOMEM);
96	ops = kobj->ktype->sysfs_ops;
97	if (ops->show) {
98		len = ops->show(kobj, attr, buf);
99		/*
100		 * It's valid to not have a 'show' so just return an
101		 * empty string.
102	 	 */
103		if (len < 0) {
104			error = -len;
105			if (error != EIO)
106				goto out;
107			buf[0] = '\0';
108		} else if (len) {
109			len--;
110			if (len >= PAGE_SIZE)
111				len = PAGE_SIZE - 1;
112			/* Trim trailing newline. */
113			buf[len] = '\0';
114		}
115	}
116
117	/* Leave one trailing byte to append a newline. */
118	error = sysctl_handle_string(oidp, buf, PAGE_SIZE - 1, req);
119	if (error != 0 || req->newptr == NULL || ops->store == NULL)
120		goto out;
121	len = strlcat(buf, "\n", PAGE_SIZE);
122	KASSERT(len < PAGE_SIZE, ("new attribute truncated"));
123	len = ops->store(kobj, attr, buf, len);
124	if (len < 0)
125		error = -len;
126out:
127	free_page((unsigned long)buf);
128
129	return (error);
130}
131
132static inline int
133sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
134{
135
136	SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
137	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
138	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
139
140	return (0);
141}
142
143static inline void
144sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
145{
146
147	if (kobj->oidp)
148		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
149}
150
151static inline void
152sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
153{
154
155	if (kobj->oidp)
156		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
157}
158
159static inline int
160sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
161{
162	struct attribute **attr;
163	struct sysctl_oid *oidp;
164
165	oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
166	    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
167	for (attr = grp->attrs; *attr != NULL; attr++) {
168		SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
169		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
170		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
171	}
172
173	return (0);
174}
175
176static inline int
177sysfs_create_dir(struct kobject *kobj)
178{
179
180	kobj->oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
181	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
182
183        return (0);
184}
185
186static inline void
187sysfs_remove_dir(struct kobject *kobj)
188{
189
190	if (kobj->oidp == NULL)
191		return;
192	sysctl_remove_oid(kobj->oidp, 1, 1);
193}
194
195#define sysfs_attr_init(attr) do {} while(0)
196
197#endif	/* _LINUX_SYSFS_H_ */
198