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 354616 2019-11-11 15:28:27Z 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		.name = __stringify(_name),				\
66		.attrs = _name##_attrs,					\
67	};								\
68	static const struct attribute_group *_name##_groups[] = {	\
69		&_name##_group,						\
70		NULL,							\
71	}
72
73/*
74 * Handle our generic '\0' terminated 'C' string.
75 * Two cases:
76 *      a variable string:  point arg1 at it, arg2 is max length.
77 *      a constant string:  point arg1 at it, arg2 is zero.
78 */
79
80static inline int
81sysctl_handle_attr(SYSCTL_HANDLER_ARGS)
82{
83	struct kobject *kobj;
84	struct attribute *attr;
85	const struct sysfs_ops *ops;
86	char *buf;
87	int error;
88	ssize_t len;
89
90	kobj = arg1;
91	attr = (struct attribute *)(intptr_t)arg2;
92	if (kobj->ktype == NULL || kobj->ktype->sysfs_ops == NULL)
93		return (ENODEV);
94	buf = (char *)get_zeroed_page(GFP_KERNEL);
95	if (buf == NULL)
96		return (ENOMEM);
97	ops = kobj->ktype->sysfs_ops;
98	if (ops->show) {
99		len = ops->show(kobj, attr, buf);
100		/*
101		 * It's valid to not have a 'show' so just return an
102		 * empty string.
103		 */
104		if (len < 0) {
105			error = -len;
106			if (error != EIO)
107				goto out;
108			buf[0] = '\0';
109		} else if (len) {
110			len--;
111			if (len >= PAGE_SIZE)
112				len = PAGE_SIZE - 1;
113			/* Trim trailing newline. */
114			buf[len] = '\0';
115		}
116	}
117
118	/* Leave one trailing byte to append a newline. */
119	error = sysctl_handle_string(oidp, buf, PAGE_SIZE - 1, req);
120	if (error != 0 || req->newptr == NULL || ops->store == NULL)
121		goto out;
122	len = strlcat(buf, "\n", PAGE_SIZE);
123	KASSERT(len < PAGE_SIZE, ("new attribute truncated"));
124	len = ops->store(kobj, attr, buf, len);
125	if (len < 0)
126		error = -len;
127out:
128	free_page((unsigned long)buf);
129
130	return (error);
131}
132
133static inline int
134sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
135{
136	struct sysctl_oid *oid;
137
138	oid = SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
139	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
140	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
141	if (!oid) {
142		return (-ENOMEM);
143	}
144
145	return (0);
146}
147
148static inline void
149sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
150{
151
152	if (kobj->oidp)
153		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
154}
155
156static inline int
157sysfs_create_files(struct kobject *kobj, const struct attribute * const *attrs)
158{
159	int error = 0;
160	int i;
161
162	for (i = 0; attrs[i] && !error; i++)
163		error = sysfs_create_file(kobj, attrs[i]);
164	while (error && --i >= 0)
165		sysfs_remove_file(kobj, attrs[i]);
166
167	return (error);
168}
169
170static inline void
171sysfs_remove_files(struct kobject *kobj, const struct attribute * const *attrs)
172{
173	int i;
174
175	for (i = 0; attrs[i]; i++)
176		sysfs_remove_file(kobj, attrs[i]);
177}
178
179static inline int
180sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
181{
182	struct attribute **attr;
183	struct sysctl_oid *oidp;
184
185	/* Don't create the group node if grp->name is undefined. */
186	if (grp->name)
187		oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
188		    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
189	else
190		oidp = kobj->oidp;
191	for (attr = grp->attrs; *attr != NULL; attr++) {
192		SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
193		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
194		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
195	}
196
197	return (0);
198}
199
200static inline void
201sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
202{
203
204	if (kobj->oidp)
205		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
206}
207
208static inline int
209sysfs_create_groups(struct kobject *kobj, const struct attribute_group **grps)
210{
211	int error = 0;
212	int i;
213
214	if (grps == NULL)
215		goto done;
216	for (i = 0; grps[i] && !error; i++)
217		error = sysfs_create_group(kobj, grps[i]);
218	while (error && --i >= 0)
219		sysfs_remove_group(kobj, grps[i]);
220done:
221	return (error);
222}
223
224static inline void
225sysfs_remove_groups(struct kobject *kobj, const struct attribute_group **grps)
226{
227	int i;
228
229	if (grps == NULL)
230		return;
231	for (i = 0; grps[i]; i++)
232		sysfs_remove_group(kobj, grps[i]);
233}
234
235static inline int
236sysfs_merge_group(struct kobject *kobj, const struct attribute_group *grp)
237{
238
239	/* Really expected behavior is to return failure if group exists. */
240	return (sysfs_create_group(kobj, grp));
241}
242
243static inline void
244sysfs_unmerge_group(struct kobject *kobj, const struct attribute_group *grp)
245{
246	struct attribute **attr;
247	struct sysctl_oid *oidp;
248
249	SLIST_FOREACH(oidp, SYSCTL_CHILDREN(kobj->oidp), oid_link) {
250		if (strcmp(oidp->oid_name, grp->name) != 0)
251			continue;
252		for (attr = grp->attrs; *attr != NULL; attr++) {
253			sysctl_remove_name(oidp, (*attr)->name, 1, 1);
254		}
255	}
256}
257
258static inline int
259sysfs_create_dir(struct kobject *kobj)
260{
261	struct sysctl_oid *oid;
262
263	oid = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
264	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
265	if (!oid) {
266		return (-ENOMEM);
267	}
268	kobj->oidp = oid;
269
270	return (0);
271}
272
273static inline void
274sysfs_remove_dir(struct kobject *kobj)
275{
276
277	if (kobj->oidp == NULL)
278		return;
279	sysctl_remove_oid(kobj->oidp, 1, 1);
280}
281
282static inline bool
283sysfs_streq(const char *s1, const char *s2)
284{
285	int l1, l2;
286
287	l1 = strlen(s1);
288	l2 = strlen(s2);
289
290	if (l1 != 0 && s1[l1-1] == '\n')
291		l1--;
292	if (l2 != 0 && s2[l2-1] == '\n')
293		l2--;
294
295	return (l1 == l2 && strncmp(s1, s2, l1) == 0);
296}
297
298#define sysfs_attr_init(attr) do {} while(0)
299
300#endif	/* _LINUX_SYSFS_H_ */
301