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  * $FreeBSD$
30  */
31 #ifndef	_LINUXKPI_LINUX_SYSFS_H_
32 #define	_LINUXKPI_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 #include <linux/stringify.h>
40 #include <linux/mm.h>
41 
42 struct sysfs_ops {
43 	ssize_t (*show)(struct kobject *, struct attribute *, char *);
44 	ssize_t (*store)(struct kobject *, struct attribute *, const char *,
45 	    size_t);
46 };
47 
48 struct attribute_group {
49 	const char		*name;
50 	mode_t			(*is_visible)(struct kobject *,
51 				    struct attribute *, int);
52 	struct attribute	**attrs;
53 };
54 
55 #define	__ATTR(_name, _mode, _show, _store) {				\
56 	.attr = { .name = __stringify(_name), .mode = _mode },		\
57 	.show = _show, .store  = _store,				\
58 }
59 #define	__ATTR_RO(_name)	__ATTR(_name, 0444, _name##_show, NULL)
60 #define	__ATTR_WO(_name)	__ATTR(_name, 0200, NULL, _name##_store)
61 #define	__ATTR_RW(_name)	__ATTR(_name, 0644, _name##_show, _name##_store)
62 #define	__ATTR_NULL	{ .attr = { .name = NULL } }
63 
64 #define	ATTRIBUTE_GROUPS(_name)						\
65 	static struct attribute_group _name##_group = {			\
66 		.name = __stringify(_name),				\
67 		.attrs = _name##_attrs,					\
68 	};								\
69 	static const struct attribute_group *_name##_groups[] = {	\
70 		&_name##_group,						\
71 		NULL,							\
72 	}
73 
74 /*
75  * Handle our generic '\0' terminated 'C' string.
76  * Two cases:
77  *      a variable string:  point arg1 at it, arg2 is max length.
78  *      a constant string:  point arg1 at it, arg2 is zero.
79  */
80 
81 static inline int
82 sysctl_handle_attr(SYSCTL_HANDLER_ARGS)
83 {
84 	struct kobject *kobj;
85 	struct attribute *attr;
86 	const struct sysfs_ops *ops;
87 	char *buf;
88 	int error;
89 	ssize_t len;
90 
91 	kobj = arg1;
92 	attr = (struct attribute *)(intptr_t)arg2;
93 	if (kobj->ktype == NULL || kobj->ktype->sysfs_ops == NULL)
94 		return (ENODEV);
95 	buf = (char *)get_zeroed_page(GFP_KERNEL);
96 	if (buf == NULL)
97 		return (ENOMEM);
98 	ops = kobj->ktype->sysfs_ops;
99 	if (ops->show) {
100 		len = ops->show(kobj, attr, buf);
101 		/*
102 		 * It's valid to not have a 'show' so just return an
103 		 * empty string.
104 		 */
105 		if (len < 0) {
106 			error = -len;
107 			if (error != EIO)
108 				goto out;
109 			buf[0] = '\0';
110 		} else if (len) {
111 			len--;
112 			if (len >= PAGE_SIZE)
113 				len = PAGE_SIZE - 1;
114 			/* Trim trailing newline. */
115 			buf[len] = '\0';
116 		}
117 	}
118 
119 	/* Leave one trailing byte to append a newline. */
120 	error = sysctl_handle_string(oidp, buf, PAGE_SIZE - 1, req);
121 	if (error != 0 || req->newptr == NULL || ops->store == NULL)
122 		goto out;
123 	len = strlcat(buf, "\n", PAGE_SIZE);
124 	KASSERT(len < PAGE_SIZE, ("new attribute truncated"));
125 	len = ops->store(kobj, attr, buf, len);
126 	if (len < 0)
127 		error = -len;
128 out:
129 	free_page((unsigned long)buf);
130 
131 	return (error);
132 }
133 
134 static inline int
135 sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
136 {
137 	struct sysctl_oid *oid;
138 
139 	oid = SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
140 	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
141 	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
142 	if (!oid) {
143 		return (-ENOMEM);
144 	}
145 
146 	return (0);
147 }
148 
149 static inline void
150 sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
151 {
152 
153 	if (kobj->oidp)
154 		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
155 }
156 
157 static inline int
158 sysfs_create_files(struct kobject *kobj, const struct attribute * const *attrs)
159 {
160 	int error = 0;
161 	int i;
162 
163 	for (i = 0; attrs[i] && !error; i++)
164 		error = sysfs_create_file(kobj, attrs[i]);
165 	while (error && --i >= 0)
166 		sysfs_remove_file(kobj, attrs[i]);
167 
168 	return (error);
169 }
170 
171 static inline void
172 sysfs_remove_files(struct kobject *kobj, const struct attribute * const *attrs)
173 {
174 	int i;
175 
176 	for (i = 0; attrs[i]; i++)
177 		sysfs_remove_file(kobj, attrs[i]);
178 }
179 
180 static inline int
181 sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
182 {
183 	struct attribute **attr;
184 	struct sysctl_oid *oidp;
185 
186 	/* Don't create the group node if grp->name is undefined. */
187 	if (grp->name)
188 		oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
189 		    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
190 	else
191 		oidp = kobj->oidp;
192 	for (attr = grp->attrs; *attr != NULL; attr++) {
193 		SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
194 		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
195 		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
196 	}
197 
198 	return (0);
199 }
200 
201 static inline void
202 sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
203 {
204 
205 	if (kobj->oidp)
206 		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
207 }
208 
209 static inline int
210 sysfs_create_groups(struct kobject *kobj, const struct attribute_group **grps)
211 {
212 	int error = 0;
213 	int i;
214 
215 	if (grps == NULL)
216 		goto done;
217 	for (i = 0; grps[i] && !error; i++)
218 		error = sysfs_create_group(kobj, grps[i]);
219 	while (error && --i >= 0)
220 		sysfs_remove_group(kobj, grps[i]);
221 done:
222 	return (error);
223 }
224 
225 static inline void
226 sysfs_remove_groups(struct kobject *kobj, const struct attribute_group **grps)
227 {
228 	int i;
229 
230 	if (grps == NULL)
231 		return;
232 	for (i = 0; grps[i]; i++)
233 		sysfs_remove_group(kobj, grps[i]);
234 }
235 
236 static inline int
237 sysfs_merge_group(struct kobject *kobj, const struct attribute_group *grp)
238 {
239 
240 	/* Really expected behavior is to return failure if group exists. */
241 	return (sysfs_create_group(kobj, grp));
242 }
243 
244 static inline void
245 sysfs_unmerge_group(struct kobject *kobj, const struct attribute_group *grp)
246 {
247 	struct attribute **attr;
248 	struct sysctl_oid *oidp;
249 
250 	SYSCTL_FOREACH(oidp, SYSCTL_CHILDREN(kobj->oidp)) {
251 		if (strcmp(oidp->oid_name, grp->name) != 0)
252 			continue;
253 		for (attr = grp->attrs; *attr != NULL; attr++) {
254 			sysctl_remove_name(oidp, (*attr)->name, 1, 1);
255 		}
256 	}
257 }
258 
259 static inline int
260 sysfs_create_dir(struct kobject *kobj)
261 {
262 	struct sysctl_oid *oid;
263 
264 	oid = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
265 	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
266 	if (!oid) {
267 		return (-ENOMEM);
268 	}
269 	kobj->oidp = oid;
270 
271 	return (0);
272 }
273 
274 static inline void
275 sysfs_remove_dir(struct kobject *kobj)
276 {
277 
278 	if (kobj->oidp == NULL)
279 		return;
280 	sysctl_remove_oid(kobj->oidp, 1, 1);
281 }
282 
283 static inline bool
284 sysfs_streq(const char *s1, const char *s2)
285 {
286 	int l1, l2;
287 
288 	l1 = strlen(s1);
289 	l2 = strlen(s2);
290 
291 	if (l1 != 0 && s1[l1-1] == '\n')
292 		l1--;
293 	if (l2 != 0 && s2[l2-1] == '\n')
294 		l2--;
295 
296 	return (l1 == l2 && strncmp(s1, s2, l1) == 0);
297 }
298 
299 static inline int
300 sysfs_emit(char *buf, const char *fmt, ...)
301 {
302 	va_list args;
303 	int i;
304 
305 	if (!buf || offset_in_page(buf)) {
306 		pr_warn("invalid sysfs_emit: buf:%p\n", buf);
307 		return (0);
308 	}
309 
310 	va_start(args, fmt);
311 	i = vscnprintf(buf, PAGE_SIZE, fmt, args);
312 	va_end(args);
313 
314 	return (i);
315 }
316 
317 static inline int
318 sysfs_emit_at(char *buf, int at, const char *fmt, ...)
319 {
320 	va_list args;
321 	int i;
322 
323 	if (!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE) {
324 		pr_warn("invalid sysfs_emit: buf:%p at:%d\n", buf, at);
325 		return (0);
326 	}
327 
328 	va_start(args, fmt);
329 	i = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
330 	va_end(args);
331 
332 	return (i);
333 }
334 
335 #define sysfs_attr_init(attr) do {} while(0)
336 
337 #endif	/* _LINUXKPI_LINUX_SYSFS_H_ */
338