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 #ifndef	_LINUXKPI_LINUX_SYSFS_H_
30 #define	_LINUXKPI_LINUX_SYSFS_H_
31 
32 #include <sys/types.h>
33 #include <sys/sysctl.h>
34 #include <sys/errno.h>
35 
36 #include <linux/kobject.h>
37 #include <linux/stringify.h>
38 #include <linux/mm.h>
39 
40 struct 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 
46 struct 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 #define	__ATTR_NULL	{ .attr = { .name = NULL } }
61 
62 #define	ATTRIBUTE_GROUPS(_name)						\
63 	static struct attribute_group _name##_group = {			\
64 		.name = __stringify(_name),				\
65 		.attrs = _name##_attrs,					\
66 	};								\
67 	static const 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 
79 static inline int
80 sysctl_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;
126 out:
127 	free_page((unsigned long)buf);
128 
129 	return (error);
130 }
131 
132 static inline int
133 sysfs_create_file(struct kobject *kobj, const struct attribute *attr)
134 {
135 	struct sysctl_oid *oid;
136 
137 	oid = SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(kobj->oidp), OID_AUTO,
138 	    attr->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE, kobj,
139 	    (uintptr_t)attr, sysctl_handle_attr, "A", "");
140 	if (!oid) {
141 		return (-ENOMEM);
142 	}
143 
144 	return (0);
145 }
146 
147 static inline void
148 sysfs_remove_file(struct kobject *kobj, const struct attribute *attr)
149 {
150 
151 	if (kobj->oidp)
152 		sysctl_remove_name(kobj->oidp, attr->name, 1, 1);
153 }
154 
155 static inline int
156 sysfs_create_files(struct kobject *kobj, const struct attribute * const *attrs)
157 {
158 	int error = 0;
159 	int i;
160 
161 	for (i = 0; attrs[i] && !error; i++)
162 		error = sysfs_create_file(kobj, attrs[i]);
163 	while (error && --i >= 0)
164 		sysfs_remove_file(kobj, attrs[i]);
165 
166 	return (error);
167 }
168 
169 static inline void
170 sysfs_remove_files(struct kobject *kobj, const struct attribute * const *attrs)
171 {
172 	int i;
173 
174 	for (i = 0; attrs[i]; i++)
175 		sysfs_remove_file(kobj, attrs[i]);
176 }
177 
178 static inline int
179 sysfs_create_group(struct kobject *kobj, const struct attribute_group *grp)
180 {
181 	struct attribute **attr;
182 	struct sysctl_oid *oidp;
183 
184 	/* Don't create the group node if grp->name is undefined. */
185 	if (grp->name)
186 		oidp = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->oidp),
187 		    OID_AUTO, grp->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, grp->name);
188 	else
189 		oidp = kobj->oidp;
190 	for (attr = grp->attrs; *attr != NULL; attr++) {
191 		SYSCTL_ADD_OID(NULL, SYSCTL_CHILDREN(oidp), OID_AUTO,
192 		    (*attr)->name, CTLTYPE_STRING|CTLFLAG_RW|CTLFLAG_MPSAFE,
193 		    kobj, (uintptr_t)*attr, sysctl_handle_attr, "A", "");
194 	}
195 
196 	return (0);
197 }
198 
199 static inline void
200 sysfs_remove_group(struct kobject *kobj, const struct attribute_group *grp)
201 {
202 
203 	if (kobj->oidp)
204 		sysctl_remove_name(kobj->oidp, grp->name, 1, 1);
205 }
206 
207 static inline int
208 sysfs_create_groups(struct kobject *kobj, const struct attribute_group **grps)
209 {
210 	int error = 0;
211 	int i;
212 
213 	if (grps == NULL)
214 		goto done;
215 	for (i = 0; grps[i] && !error; i++)
216 		error = sysfs_create_group(kobj, grps[i]);
217 	while (error && --i >= 0)
218 		sysfs_remove_group(kobj, grps[i]);
219 done:
220 	return (error);
221 }
222 
223 static inline void
224 sysfs_remove_groups(struct kobject *kobj, const struct attribute_group **grps)
225 {
226 	int i;
227 
228 	if (grps == NULL)
229 		return;
230 	for (i = 0; grps[i]; i++)
231 		sysfs_remove_group(kobj, grps[i]);
232 }
233 
234 static inline int
235 sysfs_merge_group(struct kobject *kobj, const struct attribute_group *grp)
236 {
237 
238 	/* Really expected behavior is to return failure if group exists. */
239 	return (sysfs_create_group(kobj, grp));
240 }
241 
242 static inline void
243 sysfs_unmerge_group(struct kobject *kobj, const struct attribute_group *grp)
244 {
245 	struct attribute **attr;
246 	struct sysctl_oid *oidp;
247 
248 	SYSCTL_FOREACH(oidp, SYSCTL_CHILDREN(kobj->oidp)) {
249 		if (strcmp(oidp->oid_name, grp->name) != 0)
250 			continue;
251 		for (attr = grp->attrs; *attr != NULL; attr++) {
252 			sysctl_remove_name(oidp, (*attr)->name, 1, 1);
253 		}
254 	}
255 }
256 
257 static inline int
258 sysfs_create_dir(struct kobject *kobj)
259 {
260 	struct sysctl_oid *oid;
261 
262 	oid = SYSCTL_ADD_NODE(NULL, SYSCTL_CHILDREN(kobj->parent->oidp),
263 	    OID_AUTO, kobj->name, CTLFLAG_RD|CTLFLAG_MPSAFE, NULL, kobj->name);
264 	if (!oid) {
265 		return (-ENOMEM);
266 	}
267 	kobj->oidp = oid;
268 
269 	return (0);
270 }
271 
272 static inline void
273 sysfs_remove_dir(struct kobject *kobj)
274 {
275 
276 	if (kobj->oidp == NULL)
277 		return;
278 	sysctl_remove_oid(kobj->oidp, 1, 1);
279 }
280 
281 static inline bool
282 sysfs_streq(const char *s1, const char *s2)
283 {
284 	int l1, l2;
285 
286 	l1 = strlen(s1);
287 	l2 = strlen(s2);
288 
289 	if (l1 != 0 && s1[l1-1] == '\n')
290 		l1--;
291 	if (l2 != 0 && s2[l2-1] == '\n')
292 		l2--;
293 
294 	return (l1 == l2 && strncmp(s1, s2, l1) == 0);
295 }
296 
297 static inline int
298 sysfs_emit(char *buf, const char *fmt, ...)
299 {
300 	va_list args;
301 	int i;
302 
303 	if (!buf || offset_in_page(buf)) {
304 		pr_warn("invalid sysfs_emit: buf:%p\n", buf);
305 		return (0);
306 	}
307 
308 	va_start(args, fmt);
309 	i = vscnprintf(buf, PAGE_SIZE, fmt, args);
310 	va_end(args);
311 
312 	return (i);
313 }
314 
315 static inline int
316 sysfs_emit_at(char *buf, int at, const char *fmt, ...)
317 {
318 	va_list args;
319 	int i;
320 
321 	if (!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE) {
322 		pr_warn("invalid sysfs_emit: buf:%p at:%d\n", buf, at);
323 		return (0);
324 	}
325 
326 	va_start(args, fmt);
327 	i = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
328 	va_end(args);
329 
330 	return (i);
331 }
332 
333 #define sysfs_attr_init(attr) do {} while(0)
334 
335 #endif	/* _LINUXKPI_LINUX_SYSFS_H_ */
336