| /* 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); |
| |
| /* |
| * 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 */ |