1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C), 2008-2021, OPPO Mobile Comm Corp., Ltd.
4 *             https://www.oppo.com/
5 */
6#include <linux/sysfs.h>
7#include <linux/kobject.h>
8
9#include "internal.h"
10
11enum {
12	attr_feature,
13	attr_pointer_ui,
14	attr_pointer_bool,
15};
16
17enum {
18	struct_erofs_sb_info,
19	struct_erofs_mount_opts,
20};
21
22struct erofs_attr {
23	struct attribute attr;
24	short attr_id;
25	int struct_type, offset;
26};
27
28#define EROFS_ATTR(_name, _mode, _id)					\
29static struct erofs_attr erofs_attr_##_name = {				\
30	.attr = {.name = __stringify(_name), .mode = _mode },		\
31	.attr_id = attr_##_id,						\
32}
33#define EROFS_ATTR_FUNC(_name, _mode)	EROFS_ATTR(_name, _mode, _name)
34#define EROFS_ATTR_FEATURE(_name)	EROFS_ATTR(_name, 0444, feature)
35
36#define EROFS_ATTR_OFFSET(_name, _mode, _id, _struct)	\
37static struct erofs_attr erofs_attr_##_name = {			\
38	.attr = {.name = __stringify(_name), .mode = _mode },	\
39	.attr_id = attr_##_id,					\
40	.struct_type = struct_##_struct,			\
41	.offset = offsetof(struct _struct, _name),\
42}
43
44#define EROFS_ATTR_RW(_name, _id, _struct)	\
45	EROFS_ATTR_OFFSET(_name, 0644, _id, _struct)
46
47#define EROFS_RO_ATTR(_name, _id, _struct)	\
48	EROFS_ATTR_OFFSET(_name, 0444, _id, _struct)
49
50#define EROFS_ATTR_RW_UI(_name, _struct)	\
51	EROFS_ATTR_RW(_name, pointer_ui, _struct)
52
53#define EROFS_ATTR_RW_BOOL(_name, _struct)	\
54	EROFS_ATTR_RW(_name, pointer_bool, _struct)
55
56#define ATTR_LIST(name) (&erofs_attr_##name.attr)
57
58#ifdef CONFIG_EROFS_FS_ZIP
59EROFS_ATTR_RW_UI(sync_decompress, erofs_mount_opts);
60#endif
61
62static struct attribute *erofs_attrs[] = {
63#ifdef CONFIG_EROFS_FS_ZIP
64	ATTR_LIST(sync_decompress),
65#endif
66	NULL,
67};
68ATTRIBUTE_GROUPS(erofs);
69
70/* Features this copy of erofs supports */
71EROFS_ATTR_FEATURE(zero_padding);
72EROFS_ATTR_FEATURE(compr_cfgs);
73EROFS_ATTR_FEATURE(big_pcluster);
74EROFS_ATTR_FEATURE(chunked_file);
75EROFS_ATTR_FEATURE(device_table);
76EROFS_ATTR_FEATURE(compr_head2);
77EROFS_ATTR_FEATURE(sb_chksum);
78EROFS_ATTR_FEATURE(ztailpacking);
79EROFS_ATTR_FEATURE(fragments);
80EROFS_ATTR_FEATURE(dedupe);
81
82static struct attribute *erofs_feat_attrs[] = {
83	ATTR_LIST(zero_padding),
84	ATTR_LIST(compr_cfgs),
85	ATTR_LIST(big_pcluster),
86	ATTR_LIST(chunked_file),
87	ATTR_LIST(device_table),
88	ATTR_LIST(compr_head2),
89	ATTR_LIST(sb_chksum),
90	ATTR_LIST(ztailpacking),
91	ATTR_LIST(fragments),
92	ATTR_LIST(dedupe),
93	NULL,
94};
95ATTRIBUTE_GROUPS(erofs_feat);
96
97static unsigned char *__struct_ptr(struct erofs_sb_info *sbi,
98					  int struct_type, int offset)
99{
100	if (struct_type == struct_erofs_sb_info)
101		return (unsigned char *)sbi + offset;
102	if (struct_type == struct_erofs_mount_opts)
103		return (unsigned char *)&sbi->opt + offset;
104	return NULL;
105}
106
107static ssize_t erofs_attr_show(struct kobject *kobj,
108				struct attribute *attr, char *buf)
109{
110	struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
111						s_kobj);
112	struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
113	unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
114
115	switch (a->attr_id) {
116	case attr_feature:
117		return sysfs_emit(buf, "supported\n");
118	case attr_pointer_ui:
119		if (!ptr)
120			return 0;
121		return sysfs_emit(buf, "%u\n", *(unsigned int *)ptr);
122	case attr_pointer_bool:
123		if (!ptr)
124			return 0;
125		return sysfs_emit(buf, "%d\n", *(bool *)ptr);
126	}
127	return 0;
128}
129
130static ssize_t erofs_attr_store(struct kobject *kobj, struct attribute *attr,
131						const char *buf, size_t len)
132{
133	struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
134						s_kobj);
135	struct erofs_attr *a = container_of(attr, struct erofs_attr, attr);
136	unsigned char *ptr = __struct_ptr(sbi, a->struct_type, a->offset);
137	unsigned long t;
138	int ret;
139
140	switch (a->attr_id) {
141	case attr_pointer_ui:
142		if (!ptr)
143			return 0;
144		ret = kstrtoul(skip_spaces(buf), 0, &t);
145		if (ret)
146			return ret;
147		if (t != (unsigned int)t)
148			return -ERANGE;
149#ifdef CONFIG_EROFS_FS_ZIP
150		if (!strcmp(a->attr.name, "sync_decompress") &&
151		    (t > EROFS_SYNC_DECOMPRESS_FORCE_OFF))
152			return -EINVAL;
153#endif
154		*(unsigned int *)ptr = t;
155		return len;
156	case attr_pointer_bool:
157		if (!ptr)
158			return 0;
159		ret = kstrtoul(skip_spaces(buf), 0, &t);
160		if (ret)
161			return ret;
162		if (t != 0 && t != 1)
163			return -EINVAL;
164		*(bool *)ptr = !!t;
165		return len;
166	}
167	return 0;
168}
169
170static void erofs_sb_release(struct kobject *kobj)
171{
172	struct erofs_sb_info *sbi = container_of(kobj, struct erofs_sb_info,
173						 s_kobj);
174	complete(&sbi->s_kobj_unregister);
175}
176
177static const struct sysfs_ops erofs_attr_ops = {
178	.show	= erofs_attr_show,
179	.store	= erofs_attr_store,
180};
181
182static const struct kobj_type erofs_sb_ktype = {
183	.default_groups = erofs_groups,
184	.sysfs_ops	= &erofs_attr_ops,
185	.release	= erofs_sb_release,
186};
187
188static const struct kobj_type erofs_ktype = {
189	.sysfs_ops	= &erofs_attr_ops,
190};
191
192static struct kset erofs_root = {
193	.kobj	= {.ktype = &erofs_ktype},
194};
195
196static const struct kobj_type erofs_feat_ktype = {
197	.default_groups = erofs_feat_groups,
198	.sysfs_ops	= &erofs_attr_ops,
199};
200
201static struct kobject erofs_feat = {
202	.kset	= &erofs_root,
203};
204
205int erofs_register_sysfs(struct super_block *sb)
206{
207	struct erofs_sb_info *sbi = EROFS_SB(sb);
208	char *name;
209	char *str = NULL;
210	int err;
211
212	if (erofs_is_fscache_mode(sb)) {
213		if (sbi->domain_id) {
214			str = kasprintf(GFP_KERNEL, "%s,%s", sbi->domain_id,
215					sbi->fsid);
216			if (!str)
217				return -ENOMEM;
218			name = str;
219		} else {
220			name = sbi->fsid;
221		}
222	} else {
223		name = sb->s_id;
224	}
225	sbi->s_kobj.kset = &erofs_root;
226	init_completion(&sbi->s_kobj_unregister);
227	err = kobject_init_and_add(&sbi->s_kobj, &erofs_sb_ktype, NULL, "%s", name);
228	kfree(str);
229	if (err)
230		goto put_sb_kobj;
231	return 0;
232
233put_sb_kobj:
234	kobject_put(&sbi->s_kobj);
235	wait_for_completion(&sbi->s_kobj_unregister);
236	return err;
237}
238
239void erofs_unregister_sysfs(struct super_block *sb)
240{
241	struct erofs_sb_info *sbi = EROFS_SB(sb);
242
243	if (sbi->s_kobj.state_in_sysfs) {
244		kobject_del(&sbi->s_kobj);
245		kobject_put(&sbi->s_kobj);
246		wait_for_completion(&sbi->s_kobj_unregister);
247	}
248}
249
250int __init erofs_init_sysfs(void)
251{
252	int ret;
253
254	kobject_set_name(&erofs_root.kobj, "erofs");
255	erofs_root.kobj.parent = fs_kobj;
256	ret = kset_register(&erofs_root);
257	if (ret)
258		goto root_err;
259
260	ret = kobject_init_and_add(&erofs_feat, &erofs_feat_ktype,
261				   NULL, "features");
262	if (ret)
263		goto feat_err;
264	return ret;
265
266feat_err:
267	kobject_put(&erofs_feat);
268	kset_unregister(&erofs_root);
269root_err:
270	return ret;
271}
272
273void erofs_exit_sysfs(void)
274{
275	kobject_put(&erofs_feat);
276	kset_unregister(&erofs_root);
277}
278