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9bc61ab1 DH |
1 | /* Filesystem superblock creation and reconfiguration context. |
2 | * | |
3 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public Licence | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the Licence, or (at your option) any later version. | |
10 | */ | |
11 | ||
12 | #ifndef _LINUX_FS_CONTEXT_H | |
13 | #define _LINUX_FS_CONTEXT_H | |
14 | ||
15 | #include <linux/kernel.h> | |
007ec26c | 16 | #include <linux/refcount.h> |
9bc61ab1 DH |
17 | #include <linux/errno.h> |
18 | #include <linux/security.h> | |
24dcb3d9 | 19 | #include <linux/mutex.h> |
9bc61ab1 DH |
20 | |
21 | struct cred; | |
22 | struct dentry; | |
23 | struct file_operations; | |
24 | struct file_system_type; | |
f3a09c92 | 25 | struct mnt_namespace; |
9bc61ab1 | 26 | struct net; |
f3a09c92 AV |
27 | struct pid_namespace; |
28 | struct super_block; | |
9bc61ab1 | 29 | struct user_namespace; |
f3a09c92 AV |
30 | struct vfsmount; |
31 | struct path; | |
9bc61ab1 DH |
32 | |
33 | enum fs_context_purpose { | |
34 | FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */ | |
e1a91586 | 35 | FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */ |
8d0347f6 | 36 | FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */ |
9bc61ab1 DH |
37 | }; |
38 | ||
24dcb3d9 DH |
39 | /* |
40 | * Userspace usage phase for fsopen/fspick. | |
41 | */ | |
42 | enum fs_context_phase { | |
43 | FS_CONTEXT_CREATE_PARAMS, /* Loading params for sb creation */ | |
44 | FS_CONTEXT_CREATING, /* A superblock is being created */ | |
45 | FS_CONTEXT_AWAITING_MOUNT, /* Superblock created, awaiting fsmount() */ | |
46 | FS_CONTEXT_AWAITING_RECONF, /* Awaiting initialisation for reconfiguration */ | |
47 | FS_CONTEXT_RECONF_PARAMS, /* Loading params for reconfiguration */ | |
48 | FS_CONTEXT_RECONFIGURING, /* Reconfiguring the superblock */ | |
49 | FS_CONTEXT_FAILED, /* Failed to correctly transition a context */ | |
50 | }; | |
51 | ||
31d921c7 DH |
52 | /* |
53 | * Type of parameter value. | |
54 | */ | |
55 | enum fs_value_type { | |
56 | fs_value_is_undefined, | |
57 | fs_value_is_flag, /* Value not given a value */ | |
58 | fs_value_is_string, /* Value is a string */ | |
59 | fs_value_is_blob, /* Value is a binary blob */ | |
60 | fs_value_is_filename, /* Value is a filename* + dirfd */ | |
61 | fs_value_is_filename_empty, /* Value is a filename* + dirfd + AT_EMPTY_PATH */ | |
62 | fs_value_is_file, /* Value is a file* */ | |
63 | }; | |
64 | ||
65 | /* | |
66 | * Configuration parameter. | |
67 | */ | |
68 | struct fs_parameter { | |
69 | const char *key; /* Parameter name */ | |
70 | enum fs_value_type type:8; /* The type of value here */ | |
71 | union { | |
72 | char *string; | |
73 | void *blob; | |
74 | struct filename *name; | |
75 | struct file *file; | |
76 | }; | |
77 | size_t size; | |
78 | int dirfd; | |
79 | }; | |
80 | ||
9bc61ab1 DH |
81 | /* |
82 | * Filesystem context for holding the parameters used in the creation or | |
83 | * reconfiguration of a superblock. | |
84 | * | |
85 | * Superblock creation fills in ->root whereas reconfiguration begins with this | |
86 | * already set. | |
87 | * | |
88 | * See Documentation/filesystems/mounting.txt | |
89 | */ | |
90 | struct fs_context { | |
f3a09c92 | 91 | const struct fs_context_operations *ops; |
24dcb3d9 | 92 | struct mutex uapi_mutex; /* Userspace access mutex */ |
9bc61ab1 DH |
93 | struct file_system_type *fs_type; |
94 | void *fs_private; /* The filesystem's context */ | |
95 | struct dentry *root; /* The root and superblock */ | |
96 | struct user_namespace *user_ns; /* The user namespace for this mount */ | |
97 | struct net *net_ns; /* The network namespace for this mount */ | |
98 | const struct cred *cred; /* The mounter's credentials */ | |
007ec26c | 99 | struct fc_log *log; /* Logging buffer */ |
9bc61ab1 DH |
100 | const char *source; /* The source name (eg. dev path) */ |
101 | const char *subtype; /* The subtype to set on the superblock */ | |
102 | void *security; /* Linux S&M options */ | |
cb50b348 | 103 | void *s_fs_info; /* Proposed s_fs_info */ |
9bc61ab1 DH |
104 | unsigned int sb_flags; /* Proposed superblock flags (SB_*) */ |
105 | unsigned int sb_flags_mask; /* Superblock flags that were changed */ | |
c80fa7c8 | 106 | unsigned int s_iflags; /* OR'd with sb->s_iflags */ |
846e5662 | 107 | unsigned int lsm_flags; /* Information flags from the fs to the LSM */ |
9bc61ab1 | 108 | enum fs_context_purpose purpose:8; |
24dcb3d9 | 109 | enum fs_context_phase phase:8; /* The phase the context is in */ |
9bc61ab1 | 110 | bool need_free:1; /* Need to call ops->free() */ |
cb50b348 | 111 | bool global:1; /* Goes into &init_user_ns */ |
9bc61ab1 DH |
112 | }; |
113 | ||
f3a09c92 AV |
114 | struct fs_context_operations { |
115 | void (*free)(struct fs_context *fc); | |
0b52075e | 116 | int (*dup)(struct fs_context *fc, struct fs_context *src_fc); |
3e1aeb00 | 117 | int (*parse_param)(struct fs_context *fc, struct fs_parameter *param); |
f3a09c92 AV |
118 | int (*parse_monolithic)(struct fs_context *fc, void *data); |
119 | int (*get_tree)(struct fs_context *fc); | |
120 | int (*reconfigure)(struct fs_context *fc); | |
121 | }; | |
122 | ||
9bc61ab1 DH |
123 | /* |
124 | * fs_context manipulation functions. | |
125 | */ | |
126 | extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type, | |
127 | unsigned int sb_flags); | |
8d0347f6 DH |
128 | extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry, |
129 | unsigned int sb_flags, | |
130 | unsigned int sb_flags_mask); | |
e1a91586 AV |
131 | extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type, |
132 | struct dentry *reference); | |
9bc61ab1 | 133 | |
0b52075e | 134 | extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc); |
3e1aeb00 DH |
135 | extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param); |
136 | extern int vfs_parse_fs_string(struct fs_context *fc, const char *key, | |
137 | const char *value, size_t v_size); | |
138 | extern int generic_parse_monolithic(struct fs_context *fc, void *data); | |
9bc61ab1 DH |
139 | extern int vfs_get_tree(struct fs_context *fc); |
140 | extern void put_fs_context(struct fs_context *fc); | |
141 | ||
cb50b348 AV |
142 | /* |
143 | * sget() wrapper to be called from the ->get_tree() op. | |
144 | */ | |
145 | enum vfs_get_super_keying { | |
146 | vfs_get_single_super, /* Only one such superblock may exist */ | |
147 | vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */ | |
148 | vfs_get_independent_super, /* Multiple independent superblocks may exist */ | |
149 | }; | |
150 | extern int vfs_get_super(struct fs_context *fc, | |
151 | enum vfs_get_super_keying keying, | |
152 | int (*fill_super)(struct super_block *sb, | |
153 | struct fs_context *fc)); | |
154 | ||
e7582e16 DH |
155 | extern const struct file_operations fscontext_fops; |
156 | ||
007ec26c DH |
157 | /* |
158 | * Mount error, warning and informational message logging. This structure is | |
159 | * shareable between a mount and a subordinate mount. | |
160 | */ | |
161 | struct fc_log { | |
162 | refcount_t usage; | |
163 | u8 head; /* Insertion index in buffer[] */ | |
164 | u8 tail; /* Removal index in buffer[] */ | |
165 | u8 need_free; /* Mask of kfree'able items in buffer[] */ | |
166 | struct module *owner; /* Owner module for strings that don't then need freeing */ | |
167 | char *buffer[8]; | |
168 | }; | |
169 | ||
e7582e16 DH |
170 | extern __attribute__((format(printf, 2, 3))) |
171 | void logfc(struct fs_context *fc, const char *fmt, ...); | |
c6b82263 DH |
172 | |
173 | /** | |
174 | * infof - Store supplementary informational message | |
175 | * @fc: The context in which to log the informational message | |
176 | * @fmt: The format string | |
177 | * | |
178 | * Store the supplementary informational message for the process if the process | |
179 | * has enabled the facility. | |
180 | */ | |
e7582e16 | 181 | #define infof(fc, fmt, ...) ({ logfc(fc, "i "fmt, ## __VA_ARGS__); }) |
c6b82263 DH |
182 | |
183 | /** | |
184 | * warnf - Store supplementary warning message | |
185 | * @fc: The context in which to log the error message | |
186 | * @fmt: The format string | |
187 | * | |
188 | * Store the supplementary warning message for the process if the process has | |
189 | * enabled the facility. | |
190 | */ | |
e7582e16 | 191 | #define warnf(fc, fmt, ...) ({ logfc(fc, "w "fmt, ## __VA_ARGS__); }) |
c6b82263 DH |
192 | |
193 | /** | |
194 | * errorf - Store supplementary error message | |
195 | * @fc: The context in which to log the error message | |
196 | * @fmt: The format string | |
197 | * | |
198 | * Store the supplementary error message for the process if the process has | |
199 | * enabled the facility. | |
200 | */ | |
e7582e16 | 201 | #define errorf(fc, fmt, ...) ({ logfc(fc, "e "fmt, ## __VA_ARGS__); }) |
c6b82263 DH |
202 | |
203 | /** | |
204 | * invalf - Store supplementary invalid argument error message | |
205 | * @fc: The context in which to log the error message | |
206 | * @fmt: The format string | |
207 | * | |
208 | * Store the supplementary error message for the process if the process has | |
209 | * enabled the facility and return -EINVAL. | |
210 | */ | |
211 | #define invalf(fc, fmt, ...) ({ errorf(fc, fmt, ## __VA_ARGS__); -EINVAL; }) | |
212 | ||
9bc61ab1 | 213 | #endif /* _LINUX_FS_CONTEXT_H */ |