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b4d0d230 | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
9bc61ab1 DH |
2 | /* Filesystem superblock creation and reconfiguration context. |
3 | * | |
4 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
9bc61ab1 DH |
6 | */ |
7 | ||
8 | #ifndef _LINUX_FS_CONTEXT_H | |
9 | #define _LINUX_FS_CONTEXT_H | |
10 | ||
11 | #include <linux/kernel.h> | |
007ec26c | 12 | #include <linux/refcount.h> |
9bc61ab1 DH |
13 | #include <linux/errno.h> |
14 | #include <linux/security.h> | |
24dcb3d9 | 15 | #include <linux/mutex.h> |
9bc61ab1 DH |
16 | |
17 | struct cred; | |
18 | struct dentry; | |
19 | struct file_operations; | |
20 | struct file_system_type; | |
f3a09c92 | 21 | struct mnt_namespace; |
9bc61ab1 | 22 | struct net; |
f3a09c92 AV |
23 | struct pid_namespace; |
24 | struct super_block; | |
9bc61ab1 | 25 | struct user_namespace; |
f3a09c92 AV |
26 | struct vfsmount; |
27 | struct path; | |
9bc61ab1 DH |
28 | |
29 | enum fs_context_purpose { | |
30 | FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */ | |
e1a91586 | 31 | FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */ |
8d0347f6 | 32 | FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */ |
9bc61ab1 DH |
33 | }; |
34 | ||
24dcb3d9 DH |
35 | /* |
36 | * Userspace usage phase for fsopen/fspick. | |
37 | */ | |
38 | enum fs_context_phase { | |
39 | FS_CONTEXT_CREATE_PARAMS, /* Loading params for sb creation */ | |
40 | FS_CONTEXT_CREATING, /* A superblock is being created */ | |
41 | FS_CONTEXT_AWAITING_MOUNT, /* Superblock created, awaiting fsmount() */ | |
42 | FS_CONTEXT_AWAITING_RECONF, /* Awaiting initialisation for reconfiguration */ | |
43 | FS_CONTEXT_RECONF_PARAMS, /* Loading params for reconfiguration */ | |
44 | FS_CONTEXT_RECONFIGURING, /* Reconfiguring the superblock */ | |
45 | FS_CONTEXT_FAILED, /* Failed to correctly transition a context */ | |
46 | }; | |
47 | ||
31d921c7 DH |
48 | /* |
49 | * Type of parameter value. | |
50 | */ | |
51 | enum fs_value_type { | |
52 | fs_value_is_undefined, | |
53 | fs_value_is_flag, /* Value not given a value */ | |
54 | fs_value_is_string, /* Value is a string */ | |
55 | fs_value_is_blob, /* Value is a binary blob */ | |
56 | fs_value_is_filename, /* Value is a filename* + dirfd */ | |
57 | fs_value_is_filename_empty, /* Value is a filename* + dirfd + AT_EMPTY_PATH */ | |
58 | fs_value_is_file, /* Value is a file* */ | |
59 | }; | |
60 | ||
61 | /* | |
62 | * Configuration parameter. | |
63 | */ | |
64 | struct fs_parameter { | |
65 | const char *key; /* Parameter name */ | |
66 | enum fs_value_type type:8; /* The type of value here */ | |
67 | union { | |
68 | char *string; | |
69 | void *blob; | |
70 | struct filename *name; | |
71 | struct file *file; | |
72 | }; | |
73 | size_t size; | |
74 | int dirfd; | |
75 | }; | |
76 | ||
9bc61ab1 DH |
77 | /* |
78 | * Filesystem context for holding the parameters used in the creation or | |
79 | * reconfiguration of a superblock. | |
80 | * | |
81 | * Superblock creation fills in ->root whereas reconfiguration begins with this | |
82 | * already set. | |
83 | * | |
cb1aaebe | 84 | * See Documentation/filesystems/mount_api.txt |
9bc61ab1 DH |
85 | */ |
86 | struct fs_context { | |
f3a09c92 | 87 | const struct fs_context_operations *ops; |
24dcb3d9 | 88 | struct mutex uapi_mutex; /* Userspace access mutex */ |
9bc61ab1 DH |
89 | struct file_system_type *fs_type; |
90 | void *fs_private; /* The filesystem's context */ | |
91 | struct dentry *root; /* The root and superblock */ | |
92 | struct user_namespace *user_ns; /* The user namespace for this mount */ | |
93 | struct net *net_ns; /* The network namespace for this mount */ | |
94 | const struct cred *cred; /* The mounter's credentials */ | |
007ec26c | 95 | struct fc_log *log; /* Logging buffer */ |
9bc61ab1 DH |
96 | const char *source; /* The source name (eg. dev path) */ |
97 | const char *subtype; /* The subtype to set on the superblock */ | |
98 | void *security; /* Linux S&M options */ | |
cb50b348 | 99 | void *s_fs_info; /* Proposed s_fs_info */ |
9bc61ab1 DH |
100 | unsigned int sb_flags; /* Proposed superblock flags (SB_*) */ |
101 | unsigned int sb_flags_mask; /* Superblock flags that were changed */ | |
c80fa7c8 | 102 | unsigned int s_iflags; /* OR'd with sb->s_iflags */ |
846e5662 | 103 | unsigned int lsm_flags; /* Information flags from the fs to the LSM */ |
9bc61ab1 | 104 | enum fs_context_purpose purpose:8; |
24dcb3d9 | 105 | enum fs_context_phase phase:8; /* The phase the context is in */ |
9bc61ab1 | 106 | bool need_free:1; /* Need to call ops->free() */ |
cb50b348 | 107 | bool global:1; /* Goes into &init_user_ns */ |
9bc61ab1 DH |
108 | }; |
109 | ||
f3a09c92 AV |
110 | struct fs_context_operations { |
111 | void (*free)(struct fs_context *fc); | |
0b52075e | 112 | int (*dup)(struct fs_context *fc, struct fs_context *src_fc); |
3e1aeb00 | 113 | int (*parse_param)(struct fs_context *fc, struct fs_parameter *param); |
f3a09c92 AV |
114 | int (*parse_monolithic)(struct fs_context *fc, void *data); |
115 | int (*get_tree)(struct fs_context *fc); | |
116 | int (*reconfigure)(struct fs_context *fc); | |
117 | }; | |
118 | ||
9bc61ab1 DH |
119 | /* |
120 | * fs_context manipulation functions. | |
121 | */ | |
122 | extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type, | |
123 | unsigned int sb_flags); | |
8d0347f6 DH |
124 | extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry, |
125 | unsigned int sb_flags, | |
126 | unsigned int sb_flags_mask); | |
e1a91586 AV |
127 | extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type, |
128 | struct dentry *reference); | |
9bc61ab1 | 129 | |
0b52075e | 130 | extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc); |
3e1aeb00 DH |
131 | extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param); |
132 | extern int vfs_parse_fs_string(struct fs_context *fc, const char *key, | |
133 | const char *value, size_t v_size); | |
134 | extern int generic_parse_monolithic(struct fs_context *fc, void *data); | |
9bc61ab1 DH |
135 | extern int vfs_get_tree(struct fs_context *fc); |
136 | extern void put_fs_context(struct fs_context *fc); | |
137 | ||
cb50b348 AV |
138 | /* |
139 | * sget() wrapper to be called from the ->get_tree() op. | |
140 | */ | |
141 | enum vfs_get_super_keying { | |
142 | vfs_get_single_super, /* Only one such superblock may exist */ | |
143 | vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */ | |
144 | vfs_get_independent_super, /* Multiple independent superblocks may exist */ | |
145 | }; | |
146 | extern int vfs_get_super(struct fs_context *fc, | |
147 | enum vfs_get_super_keying keying, | |
148 | int (*fill_super)(struct super_block *sb, | |
149 | struct fs_context *fc)); | |
2ac295d4 AV |
150 | extern int get_tree_nodev(struct fs_context *fc, |
151 | int (*fill_super)(struct super_block *sb, | |
152 | struct fs_context *fc)); | |
c23a0bba AV |
153 | extern int get_tree_single(struct fs_context *fc, |
154 | int (*fill_super)(struct super_block *sb, | |
155 | struct fs_context *fc)); | |
cb50b348 | 156 | |
e7582e16 DH |
157 | extern const struct file_operations fscontext_fops; |
158 | ||
007ec26c DH |
159 | /* |
160 | * Mount error, warning and informational message logging. This structure is | |
161 | * shareable between a mount and a subordinate mount. | |
162 | */ | |
163 | struct fc_log { | |
164 | refcount_t usage; | |
165 | u8 head; /* Insertion index in buffer[] */ | |
166 | u8 tail; /* Removal index in buffer[] */ | |
167 | u8 need_free; /* Mask of kfree'able items in buffer[] */ | |
168 | struct module *owner; /* Owner module for strings that don't then need freeing */ | |
169 | char *buffer[8]; | |
170 | }; | |
171 | ||
e7582e16 DH |
172 | extern __attribute__((format(printf, 2, 3))) |
173 | void logfc(struct fs_context *fc, const char *fmt, ...); | |
c6b82263 DH |
174 | |
175 | /** | |
176 | * infof - Store supplementary informational message | |
177 | * @fc: The context in which to log the informational message | |
178 | * @fmt: The format string | |
179 | * | |
180 | * Store the supplementary informational message for the process if the process | |
181 | * has enabled the facility. | |
182 | */ | |
e7582e16 | 183 | #define infof(fc, fmt, ...) ({ logfc(fc, "i "fmt, ## __VA_ARGS__); }) |
c6b82263 DH |
184 | |
185 | /** | |
186 | * warnf - Store supplementary warning message | |
187 | * @fc: The context in which to log the error message | |
188 | * @fmt: The format string | |
189 | * | |
190 | * Store the supplementary warning message for the process if the process has | |
191 | * enabled the facility. | |
192 | */ | |
e7582e16 | 193 | #define warnf(fc, fmt, ...) ({ logfc(fc, "w "fmt, ## __VA_ARGS__); }) |
c6b82263 DH |
194 | |
195 | /** | |
196 | * errorf - Store supplementary error message | |
197 | * @fc: The context in which to log the error message | |
198 | * @fmt: The format string | |
199 | * | |
200 | * Store the supplementary error message for the process if the process has | |
201 | * enabled the facility. | |
202 | */ | |
e7582e16 | 203 | #define errorf(fc, fmt, ...) ({ logfc(fc, "e "fmt, ## __VA_ARGS__); }) |
c6b82263 DH |
204 | |
205 | /** | |
206 | * invalf - Store supplementary invalid argument error message | |
207 | * @fc: The context in which to log the error message | |
208 | * @fmt: The format string | |
209 | * | |
210 | * Store the supplementary error message for the process if the process has | |
211 | * enabled the facility and return -EINVAL. | |
212 | */ | |
213 | #define invalf(fc, fmt, ...) ({ errorf(fc, fmt, ## __VA_ARGS__); -EINVAL; }) | |
214 | ||
9bc61ab1 | 215 | #endif /* _LINUX_FS_CONTEXT_H */ |