1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 1998-2022 Erez Zadok
4 * Copyright (c) 2009 Shrikar Archak
5 * Copyright (c) 2003-2022 Stony Brook University
6 * Copyright (c) 2003-2022 The Research Foundation of SUNY
7 * Copyright (c) 2023 Huawei Device Co., Ltd.
8 */
9
10 #ifndef _SHAREFS_H_
11 #define _SHAREFS_H_
12
13 #include <linux/dcache.h>
14 #include <linux/file.h>
15 #include <linux/fs.h>
16 #include <linux/mm.h>
17 #include <linux/mount.h>
18 #include <linux/namei.h>
19 #include <linux/seq_file.h>
20 #include <linux/statfs.h>
21 #include <linux/fs_stack.h>
22 #include <linux/magic.h>
23 #include <linux/uaccess.h>
24 #include <linux/slab.h>
25 #include <linux/sched.h>
26 #include <linux/xattr.h>
27 #include <linux/exportfs.h>
28
29 /* the file system name */
30 #define SHAREFS_NAME "sharefs"
31
32 /* sharefs root inode number */
33 #define SHAREFS_ROOT_INO 1
34 #define OID_ROOT 0
35 #define ROOT_UID KUIDT_INIT(OID_ROOT)
36 #define ROOT_GID KGIDT_INIT(OID_ROOT)
37 #define SHAREFS_SUPER_MAGIC 0x20230212
38
39 /* useful for tracking code reachability */
40 #define UDBG printk(KERN_DEFAULT "DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
41
42 /* file private data */
43 struct sharefs_file_info {
44 struct file *lower_file;
45 const struct vm_operations_struct *lower_vm_ops;
46 };
47
48 /* sharefs inode data in memory */
49 struct sharefs_inode_info {
50 struct inode *lower_inode;
51 struct inode vfs_inode;
52 __u16 perm;
53 };
54
55 /* sharefs dentry data in memory */
56 struct sharefs_dentry_info {
57 spinlock_t lock; /* protects lower_path */
58 struct path lower_path;
59 };
60
61 /* sharefs super-block data in memory */
62 struct sharefs_sb_info {
63 struct super_block *lower_sb;
64 /* multi user */
65 unsigned int user_id;
66 bool override;
67 bool override_support_delete;
68 };
69
70 /* operations vectors defined in specific files */
71 extern const struct file_operations sharefs_main_fops;
72 extern const struct file_operations sharefs_dir_fops;
73 extern const struct inode_operations sharefs_main_iops;
74 extern const struct inode_operations sharefs_dir_iops;
75 extern const struct inode_operations sharefs_symlink_iops;
76 extern const struct super_operations sharefs_sops;
77 extern const struct dentry_operations sharefs_dops;
78
79 extern int sharefs_init_inode_cache(void);
80 extern void sharefs_destroy_inode_cache(void);
81 extern int sharefs_init_dentry_cache(void);
82 extern void sharefs_destroy_dentry_cache(void);
83 extern int new_dentry_private_data(struct dentry *dentry);
84 extern void free_dentry_private_data(struct dentry *dentry);
85 extern struct dentry *sharefs_lookup(struct inode *dir, struct dentry *dentry,
86 unsigned int flags);
87 extern struct inode *sharefs_iget(struct super_block *sb,
88 struct inode *lower_inode);
89 extern int sharefs_interpose(struct dentry *dentry, struct super_block *sb,
90 struct path *lower_path);
91 extern int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt,
92 const char *name, unsigned int flags,
93 struct path *path);
94 extern int sharefs_parse_options(struct sharefs_sb_info *sbi,
95 const char *data);
96
97 /*
98 * inode to private data
99 *
100 * Since we use containers and the struct inode is _inside_ the
101 * sharefs_inode_info structure, SHAREFS_I will always (given a non-NULL
102 * inode pointer), return a valid non-NULL pointer.
103 */
SHAREFS_I(const struct inode * inode)104 static inline struct sharefs_inode_info *SHAREFS_I(const struct inode *inode)
105 {
106 return container_of(inode, struct sharefs_inode_info, vfs_inode);
107 }
108
109 /* dentry to private data */
110 #define SHAREFS_D(dent) ((struct sharefs_dentry_info *)(dent)->d_fsdata)
111
112 /* superblock to private data */
113 #define SHAREFS_SB(super) ((struct sharefs_sb_info *)(super)->s_fs_info)
114
115 /* file to private Data */
116 #define SHAREFS_F(file) ((struct sharefs_file_info *)((file)->private_data))
117
118 /* file to lower file */
sharefs_lower_file(const struct file * f)119 static inline struct file *sharefs_lower_file(const struct file *f)
120 {
121 return SHAREFS_F(f)->lower_file;
122 }
123
sharefs_set_lower_file(struct file * f,struct file * val)124 static inline void sharefs_set_lower_file(struct file *f, struct file *val)
125 {
126 SHAREFS_F(f)->lower_file = val;
127 }
128
129 /* inode to lower inode. */
sharefs_lower_inode(const struct inode * i)130 static inline struct inode *sharefs_lower_inode(const struct inode *i)
131 {
132 return SHAREFS_I(i)->lower_inode;
133 }
134
sharefs_set_lower_inode(struct inode * i,struct inode * val)135 static inline void sharefs_set_lower_inode(struct inode *i, struct inode *val)
136 {
137 SHAREFS_I(i)->lower_inode = val;
138 }
139
140 /* superblock to lower superblock */
sharefs_lower_super(const struct super_block * sb)141 static inline struct super_block *sharefs_lower_super(
142 const struct super_block *sb)
143 {
144 return SHAREFS_SB(sb)->lower_sb;
145 }
146
sharefs_set_lower_super(struct super_block * sb,struct super_block * val)147 static inline void sharefs_set_lower_super(struct super_block *sb,
148 struct super_block *val)
149 {
150 SHAREFS_SB(sb)->lower_sb = val;
151 }
152
153 /* path based (dentry/mnt) macros */
pathcpy(struct path * dst,const struct path * src)154 static inline void pathcpy(struct path *dst, const struct path *src)
155 {
156 dst->dentry = src->dentry;
157 dst->mnt = src->mnt;
158 }
159 /* Returns struct path. Caller must path_put it. */
sharefs_get_lower_path(const struct dentry * dent,struct path * lower_path)160 static inline void sharefs_get_lower_path(const struct dentry *dent,
161 struct path *lower_path)
162 {
163 spin_lock(&SHAREFS_D(dent)->lock);
164 pathcpy(lower_path, &SHAREFS_D(dent)->lower_path);
165 path_get(lower_path);
166 spin_unlock(&SHAREFS_D(dent)->lock);
167 return;
168 }
sharefs_put_lower_path(const struct dentry * dent,struct path * lower_path)169 static inline void sharefs_put_lower_path(const struct dentry *dent,
170 struct path *lower_path)
171 {
172 path_put(lower_path);
173 return;
174 }
sharefs_set_lower_path(const struct dentry * dent,struct path * lower_path)175 static inline void sharefs_set_lower_path(const struct dentry *dent,
176 struct path *lower_path)
177 {
178 spin_lock(&SHAREFS_D(dent)->lock);
179 pathcpy(&SHAREFS_D(dent)->lower_path, lower_path);
180 spin_unlock(&SHAREFS_D(dent)->lock);
181 return;
182 }
sharefs_reset_lower_path(const struct dentry * dent)183 static inline void sharefs_reset_lower_path(const struct dentry *dent)
184 {
185 spin_lock(&SHAREFS_D(dent)->lock);
186 SHAREFS_D(dent)->lower_path.dentry = NULL;
187 SHAREFS_D(dent)->lower_path.mnt = NULL;
188 spin_unlock(&SHAREFS_D(dent)->lock);
189 return;
190 }
sharefs_put_reset_lower_path(const struct dentry * dent)191 static inline void sharefs_put_reset_lower_path(const struct dentry *dent)
192 {
193 struct path lower_path;
194 spin_lock(&SHAREFS_D(dent)->lock);
195 pathcpy(&lower_path, &SHAREFS_D(dent)->lower_path);
196 SHAREFS_D(dent)->lower_path.dentry = NULL;
197 SHAREFS_D(dent)->lower_path.mnt = NULL;
198 spin_unlock(&SHAREFS_D(dent)->lock);
199 path_put(&lower_path);
200 return;
201 }
202
203 /* locking helpers */
lock_parent(struct dentry * dentry)204 static inline struct dentry *lock_parent(struct dentry *dentry)
205 {
206 struct dentry *dir = dget_parent(dentry);
207 inode_lock_nested(d_inode(dir), I_MUTEX_PARENT);
208 return dir;
209 }
210
unlock_dir(struct dentry * dir)211 static inline void unlock_dir(struct dentry *dir)
212 {
213 inode_unlock(d_inode(dir));
214 dput(dir);
215 }
216
str_n_case_eq(const char * s1,const char * s2,size_t len)217 static inline bool str_n_case_eq(const char *s1, const char *s2, size_t len)
218 {
219 return !strncasecmp(s1, s2, len);
220 }
221
qstr_case_eq(const struct qstr * q1,const struct qstr * q2)222 static inline bool qstr_case_eq(const struct qstr *q1, const struct qstr *q2)
223 {
224 return q1->len == q2->len && str_n_case_eq(q1->name, q2->name, q2->len);
225 }
226 /*****************************************************************************
227 * log print helpers
228 *****************************************************************************/
229 __printf(4, 5) void __sharefs_log(const char *level, const bool ratelimited,
230 const char *function, const char *fmt, ...);
231 #define sharefs_err(fmt, ...) \
232 __sharefs_log(KERN_ERR, false, __func__, fmt, ##__VA_ARGS__)
233 #define sharefs_warning(fmt, ...) \
234 __sharefs_log(KERN_WARNING, false, __func__, fmt, ##__VA_ARGS__)
235 #define sharefs_info(fmt, ...) \
236 __sharefs_log(KERN_INFO, false, __func__, fmt, ##__VA_ARGS__)
237 #define sharefs_err_ratelimited(fmt, ...) \
238 __sharefs_log(KERN_ERR, true, __func__, fmt, ##__VA_ARGS__)
239 #define sharefs_warning_ratelimited(fmt, ...) \
240 __sharefs_log(KERN_WARNING, true, __func__, fmt, ##__VA_ARGS__)
241 #define sharefs_info_ratelimited(fmt, ...) \
242 __sharefs_log(KERN_INFO, true, __func__, fmt, ##__VA_ARGS__)
243
244 #endif /* not _SHAREFS_H_ */
245