1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
|
/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Filesystem superblock creation and reconfiguration context.
*
* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#ifndef _LINUX_FS_CONTEXT_H
#define _LINUX_FS_CONTEXT_H
#include <linux/kernel.h>
#include <linux/refcount.h>
#include <linux/errno.h>
#include <linux/security.h>
#include <linux/mutex.h>
struct cred;
struct dentry;
struct file_operations;
struct file_system_type;
struct mnt_namespace;
struct net;
struct pid_namespace;
struct super_block;
struct user_namespace;
struct vfsmount;
struct path;
enum fs_context_purpose {
FS_CONTEXT_FOR_MOUNT, /* New superblock for explicit mount */
FS_CONTEXT_FOR_SUBMOUNT, /* New superblock for automatic submount */
FS_CONTEXT_FOR_RECONFIGURE, /* Superblock reconfiguration (remount) */
};
/*
* Userspace usage phase for fsopen/fspick.
*/
enum fs_context_phase {
FS_CONTEXT_CREATE_PARAMS, /* Loading params for sb creation */
FS_CONTEXT_CREATING, /* A superblock is being created */
FS_CONTEXT_AWAITING_MOUNT, /* Superblock created, awaiting fsmount() */
FS_CONTEXT_AWAITING_RECONF, /* Awaiting initialisation for reconfiguration */
FS_CONTEXT_RECONF_PARAMS, /* Loading params for reconfiguration */
FS_CONTEXT_RECONFIGURING, /* Reconfiguring the superblock */
FS_CONTEXT_FAILED, /* Failed to correctly transition a context */
};
/*
* Type of parameter value.
*/
enum fs_value_type {
fs_value_is_undefined,
fs_value_is_flag, /* Value not given a value */
fs_value_is_string, /* Value is a string */
fs_value_is_blob, /* Value is a binary blob */
fs_value_is_filename, /* Value is a filename* + dirfd */
fs_value_is_file, /* Value is a file* */
};
/*
* Configuration parameter.
*/
struct fs_parameter {
const char *key; /* Parameter name */
enum fs_value_type type:8; /* The type of value here */
union {
char *string;
void *blob;
struct filename *name;
struct file *file;
};
size_t size;
int dirfd;
};
struct p_log {
const char *prefix;
struct fc_log *log;
};
/*
* Filesystem context for holding the parameters used in the creation or
* reconfiguration of a superblock.
*
* Superblock creation fills in ->root whereas reconfiguration begins with this
* already set.
*
* See Documentation/filesystems/mount_api.rst
*/
struct fs_context {
const struct fs_context_operations *ops;
struct mutex uapi_mutex; /* Userspace access mutex */
struct file_system_type *fs_type;
void *fs_private; /* The filesystem's context */
void *sget_key;
struct dentry *root; /* The root and superblock */
struct user_namespace *user_ns; /* The user namespace for this mount */
struct net *net_ns; /* The network namespace for this mount */
const struct cred *cred; /* The mounter's credentials */
struct p_log log; /* Logging buffer */
const char *source; /* The source name (eg. dev path) */
void *security; /* Linux S&M options */
void *s_fs_info; /* Proposed s_fs_info */
unsigned int sb_flags; /* Proposed superblock flags (SB_*) */
unsigned int sb_flags_mask; /* Superblock flags that were changed */
unsigned int s_iflags; /* OR'd with sb->s_iflags */
unsigned int lsm_flags; /* Information flags from the fs to the LSM */
enum fs_context_purpose purpose:8;
enum fs_context_phase phase:8; /* The phase the context is in */
bool need_free:1; /* Need to call ops->free() */
bool global:1; /* Goes into &init_user_ns */
bool oldapi:1; /* Coming from mount(2) */
};
struct fs_context_operations {
void (*free)(struct fs_context *fc);
int (*dup)(struct fs_context *fc, struct fs_context *src_fc);
int (*parse_param)(struct fs_context *fc, struct fs_parameter *param);
int (*parse_monolithic)(struct fs_context *fc, void *data);
int (*get_tree)(struct fs_context *fc);
int (*reconfigure)(struct fs_context *fc);
};
/*
* fs_context manipulation functions.
*/
extern struct fs_context *fs_context_for_mount(struct file_system_type *fs_type,
unsigned int sb_flags);
extern struct fs_context *fs_context_for_reconfigure(struct dentry *dentry,
unsigned int sb_flags,
unsigned int sb_flags_mask);
extern struct fs_context *fs_context_for_submount(struct file_system_type *fs_type,
struct dentry *reference);
extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
const char *value, size_t v_size);
extern int generic_parse_monolithic(struct fs_context *fc, void *data);
extern int vfs_get_tree(struct fs_context *fc);
extern void put_fs_context(struct fs_context *fc);
extern int vfs_parse_fs_param_source(struct fs_context *fc,
struct fs_parameter *param);
/*
* sget() wrappers to be called from the ->get_tree() op.
*/
enum vfs_get_super_keying {
vfs_get_single_super, /* Only one such superblock may exist */
vfs_get_single_reconf_super, /* As above, but reconfigure if it exists */
vfs_get_keyed_super, /* Superblocks with different s_fs_info keys may exist */
vfs_get_independent_super, /* Multiple independent superblocks may exist */
};
extern int vfs_get_super(struct fs_context *fc,
enum vfs_get_super_keying keying,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
extern int get_tree_nodev(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
extern int get_tree_single(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
extern int get_tree_single_reconf(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
extern int get_tree_keyed(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc),
void *key);
extern int get_tree_bdev(struct fs_context *fc,
int (*fill_super)(struct super_block *sb,
struct fs_context *fc));
extern const struct file_operations fscontext_fops;
/*
* Mount error, warning and informational message logging. This structure is
* shareable between a mount and a subordinate mount.
*/
struct fc_log {
refcount_t usage;
u8 head; /* Insertion index in buffer[] */
u8 tail; /* Removal index in buffer[] */
u8 need_free; /* Mask of kfree'able items in buffer[] */
struct module *owner; /* Owner module for strings that don't then need freeing */
char *buffer[8];
};
extern __attribute__((format(printf, 4, 5)))
void logfc(struct fc_log *log, const char *prefix, char level, const char *fmt, ...);
#define __logfc(fc, l, fmt, ...) logfc((fc)->log.log, NULL, \
l, fmt, ## __VA_ARGS__)
#define __plog(p, l, fmt, ...) logfc((p)->log, (p)->prefix, \
l, fmt, ## __VA_ARGS__)
/**
* infof - Store supplementary informational message
* @fc: The context in which to log the informational message
* @fmt: The format string
*
* Store the supplementary informational message for the process if the process
* has enabled the facility.
*/
#define infof(fc, fmt, ...) __logfc(fc, 'i', fmt, ## __VA_ARGS__)
#define info_plog(p, fmt, ...) __plog(p, 'i', fmt, ## __VA_ARGS__)
#define infofc(p, fmt, ...) __plog((&(fc)->log), 'i', fmt, ## __VA_ARGS__)
/**
* warnf - Store supplementary warning message
* @fc: The context in which to log the error message
* @fmt: The format string
*
* Store the supplementary warning message for the process if the process has
* enabled the facility.
*/
#define warnf(fc, fmt, ...) __logfc(fc, 'w', fmt, ## __VA_ARGS__)
#define warn_plog(p, fmt, ...) __plog(p, 'w', fmt, ## __VA_ARGS__)
#define warnfc(fc, fmt, ...) __plog((&(fc)->log), 'w', fmt, ## __VA_ARGS__)
/**
* errorf - Store supplementary error message
* @fc: The context in which to log the error message
* @fmt: The format string
*
* Store the supplementary error message for the process if the process has
* enabled the facility.
*/
#define errorf(fc, fmt, ...) __logfc(fc, 'e', fmt, ## __VA_ARGS__)
#define error_plog(p, fmt, ...) __plog(p, 'e', fmt, ## __VA_ARGS__)
#define errorfc(fc, fmt, ...) __plog((&(fc)->log), 'e', fmt, ## __VA_ARGS__)
/**
* invalf - Store supplementary invalid argument error message
* @fc: The context in which to log the error message
* @fmt: The format string
*
* Store the supplementary error message for the process if the process has
* enabled the facility and return -EINVAL.
*/
#define invalf(fc, fmt, ...) (errorf(fc, fmt, ## __VA_ARGS__), -EINVAL)
#define inval_plog(p, fmt, ...) (error_plog(p, fmt, ## __VA_ARGS__), -EINVAL)
#define invalfc(fc, fmt, ...) (errorfc(fc, fmt, ## __VA_ARGS__), -EINVAL)
#endif /* _LINUX_FS_CONTEXT_H */
|
