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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> | |
16 | #include <linux/errno.h> | |
17 | #include <linux/security.h> | |
18 | ||
19 | struct cred; | |
20 | struct dentry; | |
21 | struct file_operations; | |
22 | struct file_system_type; | |
f3a09c92 | 23 | struct mnt_namespace; |
9bc61ab1 | 24 | struct net; |
f3a09c92 AV |
25 | struct pid_namespace; |
26 | struct super_block; | |
9bc61ab1 | 27 | struct user_namespace; |
f3a09c92 AV |
28 | struct vfsmount; |
29 | struct path; | |
9bc61ab1 DH |
30 | |
31 | enum fs_context_purpose { | |
32 | FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */ | |
e1a91586 | 33 | FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */ |
8d0347f6 | 34 | FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */ |
9bc61ab1 DH |
35 | }; |
36 | ||
31d921c7 DH |
37 | /* |
38 | * Type of parameter value. | |
39 | */ | |
40 | enum fs_value_type { | |
41 | fs_value_is_undefined, | |
42 | fs_value_is_flag, /* Value not given a value */ | |
43 | fs_value_is_string, /* Value is a string */ | |
44 | fs_value_is_blob, /* Value is a binary blob */ | |
45 | fs_value_is_filename, /* Value is a filename* + dirfd */ | |
46 | fs_value_is_filename_empty, /* Value is a filename* + dirfd + AT_EMPTY_PATH */ | |
47 | fs_value_is_file, /* Value is a file* */ | |
48 | }; | |
49 | ||
50 | /* | |
51 | * Configuration parameter. | |
52 | */ | |
53 | struct fs_parameter { | |
54 | const char *key; /* Parameter name */ | |
55 | enum fs_value_type type:8; /* The type of value here */ | |
56 | union { | |
57 | char *string; | |
58 | void *blob; | |
59 | struct filename *name; | |
60 | struct file *file; | |
61 | }; | |
62 | size_t size; | |
63 | int dirfd; | |
64 | }; | |
65 | ||
9bc61ab1 DH |
66 | /* |
67 | * Filesystem context for holding the parameters used in the creation or | |
68 | * reconfiguration of a superblock. | |
69 | * | |
70 | * Superblock creation fills in ->root whereas reconfiguration begins with this | |
71 | * already set. | |
72 | * | |
73 | * See Documentation/filesystems/mounting.txt | |
74 | */ | |
75 | struct fs_context { | |
f3a09c92 | 76 | const struct fs_context_operations *ops; |
9bc61ab1 DH |
77 | struct file_system_type *fs_type; |
78 | void *fs_private; /* The filesystem's context */ | |
79 | struct dentry *root; /* The root and superblock */ | |
80 | struct user_namespace *user_ns; /* The user namespace for this mount */ | |
81 | struct net *net_ns; /* The network namespace for this mount */ | |
82 | const struct cred *cred; /* The mounter's credentials */ | |
83 | const char *source; /* The source name (eg. dev path) */ | |
84 | const char *subtype; /* The subtype to set on the superblock */ | |
85 | void *security; /* Linux S&M options */ | |
86 | unsigned int sb_flags; /* Proposed superblock flags (SB_*) */ | |
87 | unsigned int sb_flags_mask; /* Superblock flags that were changed */ | |
846e5662 | 88 | unsigned int lsm_flags; /* Information flags from the fs to the LSM */ |
9bc61ab1 DH |
89 | enum fs_context_purpose purpose:8; |
90 | bool need_free:1; /* Need to call ops->free() */ | |
91 | }; | |
92 | ||
f3a09c92 AV |
93 | struct fs_context_operations { |
94 | void (*free)(struct fs_context *fc); | |
3e1aeb00 | 95 | int (*parse_param)(struct fs_context *fc, struct fs_parameter *param); |
f3a09c92 AV |
96 | int (*parse_monolithic)(struct fs_context *fc, void *data); |
97 | int (*get_tree)(struct fs_context *fc); | |
98 | int (*reconfigure)(struct fs_context *fc); | |
99 | }; | |
100 | ||
9bc61ab1 DH |
101 | /* |
102 | * fs_context manipulation functions. | |
103 | */ | |
104 | extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type, | |
105 | unsigned int sb_flags); | |
8d0347f6 DH |
106 | extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry, |
107 | unsigned int sb_flags, | |
108 | unsigned int sb_flags_mask); | |
e1a91586 AV |
109 | extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type, |
110 | struct dentry *reference); | |
9bc61ab1 | 111 | |
3e1aeb00 DH |
112 | extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param); |
113 | extern int vfs_parse_fs_string(struct fs_context *fc, const char *key, | |
114 | const char *value, size_t v_size); | |
115 | extern int generic_parse_monolithic(struct fs_context *fc, void *data); | |
9bc61ab1 DH |
116 | extern int vfs_get_tree(struct fs_context *fc); |
117 | extern void put_fs_context(struct fs_context *fc); | |
118 | ||
c6b82263 DH |
119 | #define logfc(FC, FMT, ...) pr_notice(FMT, ## __VA_ARGS__) |
120 | ||
121 | /** | |
122 | * infof - Store supplementary informational message | |
123 | * @fc: The context in which to log the informational message | |
124 | * @fmt: The format string | |
125 | * | |
126 | * Store the supplementary informational message for the process if the process | |
127 | * has enabled the facility. | |
128 | */ | |
129 | #define infof(fc, fmt, ...) ({ logfc(fc, fmt, ## __VA_ARGS__); }) | |
130 | ||
131 | /** | |
132 | * warnf - Store supplementary warning message | |
133 | * @fc: The context in which to log the error message | |
134 | * @fmt: The format string | |
135 | * | |
136 | * Store the supplementary warning message for the process if the process has | |
137 | * enabled the facility. | |
138 | */ | |
139 | #define warnf(fc, fmt, ...) ({ logfc(fc, fmt, ## __VA_ARGS__); }) | |
140 | ||
141 | /** | |
142 | * errorf - Store supplementary error message | |
143 | * @fc: The context in which to log the error message | |
144 | * @fmt: The format string | |
145 | * | |
146 | * Store the supplementary error message for the process if the process has | |
147 | * enabled the facility. | |
148 | */ | |
149 | #define errorf(fc, fmt, ...) ({ logfc(fc, fmt, ## __VA_ARGS__); }) | |
150 | ||
151 | /** | |
152 | * invalf - Store supplementary invalid argument error message | |
153 | * @fc: The context in which to log the error message | |
154 | * @fmt: The format string | |
155 | * | |
156 | * Store the supplementary error message for the process if the process has | |
157 | * enabled the facility and return -EINVAL. | |
158 | */ | |
159 | #define invalf(fc, fmt, ...) ({ errorf(fc, fmt, ## __VA_ARGS__); -EINVAL; }) | |
160 | ||
9bc61ab1 | 161 | #endif /* _LINUX_FS_CONTEXT_H */ |