[thirdparty/kernel/stable.git] / include / linux / fs_context.h

/* 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;	/* LSM 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 */
	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) */
	bool			exclusive:1;    /* create new superblock, reject existing one */
};

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);
int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
			     char *(*sep)(char **));
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);
extern void fc_drop_locked(struct fs_context *fc);
int reconfigure_single(struct super_block *s,
		       int flags, void *data);

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_keyed(struct fs_context *fc,
			 int (*fill_super)(struct super_block *sb,
					   struct fs_context *fc),
			 void *key);

int setup_bdev_super(struct super_block *sb, int sb_flags,
		struct fs_context *fc);
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 */
Commit	Line	Data
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>
9bc61ab1 DH	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;
f3a09c92 AV	24	struct super_block;
9bc61ab1	25	struct user_namespace;
f3a09c92 AV	26	struct vfsmount;
f3a09c92 AV	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	};
9bc61ab1 DH	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 */
31d921c7 DH	57	fs_value_is_file, /* Value is a file* */
	58	};
	59
	60	/*
	61	* Configuration parameter.
	62	*/
	63	struct fs_parameter {
	64	const char key; / Parameter name */
	65	enum fs_value_type type:8; /* The type of value here */
	66	union {
	67	char *string;
	68	void *blob;
	69	struct filename *name;
	70	struct file *file;
	71	};
	72	size_t size;
	73	int dirfd;
	74	};
	75
3fbb8d55 AV	76	struct p_log {
	77	const char *prefix;
	78	struct fc_log *log;
	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	*
791a17ee	88	* See Documentation/filesystems/mount_api.rst
9bc61ab1 DH	89	*/
9bc61ab1 DH	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;
9bc61ab1 DH	94	void fs_private; / The filesystem's context */
fe62c3a4	95	void *sget_key;
9bc61ab1 DH	96	struct dentry root; / The root and superblock */
	97	struct user_namespace user_ns; / The user namespace for this mount */
	98	struct net net_ns; / The network namespace for this mount */
	99	const struct cred cred; / The mounter's credentials */
cc3c0b53	100	struct p_log log; /* Logging buffer */
9bc61ab1	101	const char source; / The source name (eg. dev path) */
3b87d9f4	102	void security; / LSM options */
cb50b348	103	void s_fs_info; / Proposed s_fs_info */
9bc61ab1 DH	104	unsigned int sb_flags; /* Proposed superblock flags (SB_) /
9bc61ab1 DH	105	unsigned int sb_flags_mask; /* Superblock flags that were changed */
c80fa7c8	106	unsigned int s_iflags; /* OR'd with sb->s_iflags */
9bc61ab1	107	enum fs_context_purpose purpose:8;
24dcb3d9	108	enum fs_context_phase phase:8; /* The phase the context is in */
9bc61ab1	109	bool need_free:1; /* Need to call ops->free() */
cb50b348	110	bool global:1; /* Goes into &init_user_ns */
b330966f	111	bool oldapi:1; /* Coming from mount(2) */
22ed7ecd	112	bool exclusive:1; /* create new superblock, reject existing one */
9bc61ab1 DH	113	};
9bc61ab1 DH	114
f3a09c92 AV	115	struct fs_context_operations {
f3a09c92 AV	116	void (free)(struct fs_context fc);
0b52075e	117	int (dup)(struct fs_context fc, struct fs_context *src_fc);
3e1aeb00	118	int (parse_param)(struct fs_context fc, struct fs_parameter *param);
f3a09c92 AV	119	int (parse_monolithic)(struct fs_context fc, void *data);
	120	int (get_tree)(struct fs_context fc);
	121	int (reconfigure)(struct fs_context fc);
	122	};
	123
9bc61ab1 DH	124	/*
	125	* fs_context manipulation functions.
	126	*/
	127	extern struct fs_context fs_context_for_mount(struct file_system_type fs_type,
	128	unsigned int sb_flags);
8d0347f6 DH	129	extern struct fs_context fs_context_for_reconfigure(struct dentry dentry,
	130	unsigned int sb_flags,
	131	unsigned int sb_flags_mask);
e1a91586 AV	132	extern struct fs_context fs_context_for_submount(struct file_system_type fs_type,
e1a91586 AV	133	struct dentry *reference);
9bc61ab1	134
0b52075e	135	extern struct fs_context vfs_dup_fs_context(struct fs_context fc);
3e1aeb00 DH	136	extern int vfs_parse_fs_param(struct fs_context fc, struct fs_parameter param);
	137	extern int vfs_parse_fs_string(struct fs_context fc, const char key,
	138	const char *value, size_t v_size);
e001d144 AG	139	int vfs_parse_monolithic_sep(struct fs_context fc, void data,
e001d144 AG	140	char (sep)(char **));
3e1aeb00	141	extern int generic_parse_monolithic(struct fs_context fc, void data);
9bc61ab1 DH	142	extern int vfs_get_tree(struct fs_context *fc);
9bc61ab1 DH	143	extern void put_fs_context(struct fs_context *fc);
d1d488d8 CB	144	extern int vfs_parse_fs_param_source(struct fs_context *fc,
d1d488d8 CB	145	struct fs_parameter *param);
1e7107c5	146	extern void fc_drop_locked(struct fs_context *fc);
a6097180 N	147	int reconfigure_single(struct super_block *s,
a6097180 N	148	int flags, void *data);
9bc61ab1	149
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	153	extern int get_tree_single(struct fs_context *fc,
43ce4c1f DH	154	int (fill_super)(struct super_block sb,
43ce4c1f DH	155	struct fs_context *fc));
533770cc AV	156	extern int get_tree_keyed(struct fs_context *fc,
	157	int (fill_super)(struct super_block sb,
	158	struct fs_context *fc),
	159	void *key);
cb50b348	160
cf6da236 CH	161	int setup_bdev_super(struct super_block *sb, int sb_flags,
cf6da236 CH	162	struct fs_context *fc);
fe62c3a4 DH	163	extern int get_tree_bdev(struct fs_context *fc,
	164	int (fill_super)(struct super_block sb,
	165	struct fs_context *fc));
	166
e7582e16 DH	167	extern const struct file_operations fscontext_fops;
e7582e16 DH	168
007ec26c DH	169	/*
	170	* Mount error, warning and informational message logging. This structure is
	171	* shareable between a mount and a subordinate mount.
	172	*/
	173	struct fc_log {
	174	refcount_t usage;
	175	u8 head; /* Insertion index in buffer[] */
	176	u8 tail; /* Removal index in buffer[] */
	177	u8 need_free; /* Mask of kfree'able items in buffer[] */
	178	struct module owner; / Owner module for strings that don't then need freeing */
	179	char *buffer[8];
	180	};
	181
9f09f649 AV	182	extern __attribute__((format(printf, 4, 5)))
9f09f649 AV	183	void logfc(struct fc_log log, const char prefix, char level, const char *fmt, ...);
c6b82263	184
cc3c0b53	185	#define __logfc(fc, l, fmt, ...) logfc((fc)->log.log, NULL, \
7f5d3814	186	l, fmt, ## __VA_ARGS__)
3fbb8d55 AV	187	#define __plog(p, l, fmt, ...) logfc((p)->log, (p)->prefix, \
3fbb8d55 AV	188	l, fmt, ## __VA_ARGS__)
c6b82263 DH	189	/**
	190	* infof - Store supplementary informational message
	191	* @fc: The context in which to log the informational message
	192	* @fmt: The format string
	193	*
	194	* Store the supplementary informational message for the process if the process
	195	* has enabled the facility.
	196	*/
9f09f649	197	#define infof(fc, fmt, ...) __logfc(fc, 'i', fmt, ## __VA_ARGS__)
3fbb8d55	198	#define info_plog(p, fmt, ...) __plog(p, 'i', fmt, ## __VA_ARGS__)
a3ff937b	199	#define infofc(p, fmt, ...) __plog((&(fc)->log), 'i', fmt, ## __VA_ARGS__)
c6b82263 DH	200
	201	/**
	202	* warnf - Store supplementary warning message
	203	* @fc: The context in which to log the error message
	204	* @fmt: The format string
	205	*
	206	* Store the supplementary warning message for the process if the process has
	207	* enabled the facility.
	208	*/
9f09f649	209	#define warnf(fc, fmt, ...) __logfc(fc, 'w', fmt, ## __VA_ARGS__)
3fbb8d55	210	#define warn_plog(p, fmt, ...) __plog(p, 'w', fmt, ## __VA_ARGS__)
a3ff937b	211	#define warnfc(fc, fmt, ...) __plog((&(fc)->log), 'w', fmt, ## __VA_ARGS__)
c6b82263 DH	212
	213	/**
	214	* errorf - Store supplementary error message
	215	* @fc: The context in which to log the error message
	216	* @fmt: The format string
	217	*
	218	* Store the supplementary error message for the process if the process has
	219	* enabled the facility.
	220	*/
9f09f649	221	#define errorf(fc, fmt, ...) __logfc(fc, 'e', fmt, ## __VA_ARGS__)
3fbb8d55	222	#define error_plog(p, fmt, ...) __plog(p, 'e', fmt, ## __VA_ARGS__)
a3ff937b	223	#define errorfc(fc, fmt, ...) __plog((&(fc)->log), 'e', fmt, ## __VA_ARGS__)
c6b82263 DH	224
	225	/**
	226	* invalf - Store supplementary invalid argument error message
	227	* @fc: The context in which to log the error message
	228	* @fmt: The format string
	229	*
	230	* Store the supplementary error message for the process if the process has
	231	* enabled the facility and return -EINVAL.
	232	*/
9f09f649	233	#define invalf(fc, fmt, ...) (errorf(fc, fmt, ## __VA_ARGS__), -EINVAL)
3fbb8d55	234	#define inval_plog(p, fmt, ...) (error_plog(p, fmt, ## __VA_ARGS__), -EINVAL)
a3ff937b	235	#define invalfc(fc, fmt, ...) (errorfc(fc, fmt, ## __VA_ARGS__), -EINVAL)
c6b82263	236
9bc61ab1	237	#endif /* _LINUX_FS_CONTEXT_H */