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![Eric W. Biederman](/assets/img/avatar_default.png)
The problem: proc_net files remember which network namespace the are against but do not remember hold a reference count (as that would pin the network namespace). So we currently have a small window where the reference count on a network namespace may be incremented when opening a /proc file when it has already gone to zero. To fix this introduce maybe_get_net and get_proc_net. maybe_get_net increments the network namespace reference count only if it is greater then zero, ensuring we don't increment a reference count after it has gone to zero. get_proc_net handles all of the magic to go from a proc inode to the network namespace instance and call maybe_get_net on it. PROC_NET the old accessor is removed so that we don't get confused and use the wrong helper function. Then I fix up the callers to use get_proc_net and handle the case case where get_proc_net returns NULL. In that case I return -ENXIO because effectively the network namespace has already gone away so the files we are trying to access don't exist anymore. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
283 lines
8.4 KiB
C
283 lines
8.4 KiB
C
#ifndef _LINUX_PROC_FS_H
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#define _LINUX_PROC_FS_H
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/spinlock.h>
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#include <linux/magic.h>
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#include <asm/atomic.h>
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struct net;
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struct completion;
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/*
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* The proc filesystem constants/structures
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*/
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/*
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* Offset of the first process in the /proc root directory..
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*/
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#define FIRST_PROCESS_ENTRY 256
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/*
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* We always define these enumerators
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*/
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enum {
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PROC_ROOT_INO = 1,
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};
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/*
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* This is not completely implemented yet. The idea is to
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* create an in-memory tree (like the actual /proc filesystem
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* tree) of these proc_dir_entries, so that we can dynamically
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* add new files to /proc.
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*
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* The "next" pointer creates a linked list of one /proc directory,
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* while parent/subdir create the directory structure (every
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* /proc file has a parent, but "subdir" is NULL for all
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* non-directory entries).
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*
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* "get_info" is called at "read", while "owner" is used to protect module
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* from unloading while proc_dir_entry is in use
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*/
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typedef int (read_proc_t)(char *page, char **start, off_t off,
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int count, int *eof, void *data);
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typedef int (write_proc_t)(struct file *file, const char __user *buffer,
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unsigned long count, void *data);
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typedef int (get_info_t)(char *, char **, off_t, int);
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struct proc_dir_entry {
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unsigned int low_ino;
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unsigned short namelen;
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const char *name;
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mode_t mode;
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nlink_t nlink;
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uid_t uid;
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gid_t gid;
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loff_t size;
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const struct inode_operations *proc_iops;
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/*
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* NULL ->proc_fops means "PDE is going away RSN" or
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* "PDE is just created". In either case, e.g. ->read_proc won't be
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* called because it's too late or too early, respectively.
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*
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* If you're allocating ->proc_fops dynamically, save a pointer
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* somewhere.
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*/
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const struct file_operations *proc_fops;
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get_info_t *get_info;
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struct module *owner;
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struct proc_dir_entry *next, *parent, *subdir;
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void *data;
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read_proc_t *read_proc;
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write_proc_t *write_proc;
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atomic_t count; /* use count */
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int deleted; /* delete flag */
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int pde_users; /* number of callers into module in progress */
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spinlock_t pde_unload_lock; /* proc_fops checks and pde_users bumps */
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struct completion *pde_unload_completion;
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};
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struct kcore_list {
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struct kcore_list *next;
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unsigned long addr;
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size_t size;
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};
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struct vmcore {
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struct list_head list;
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unsigned long long paddr;
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unsigned long long size;
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loff_t offset;
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};
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#ifdef CONFIG_PROC_FS
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extern struct proc_dir_entry proc_root;
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extern struct proc_dir_entry *proc_root_fs;
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extern struct proc_dir_entry *proc_bus;
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extern struct proc_dir_entry *proc_root_driver;
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extern struct proc_dir_entry *proc_root_kcore;
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extern spinlock_t proc_subdir_lock;
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extern void proc_root_init(void);
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extern void proc_misc_init(void);
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struct mm_struct;
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void proc_flush_task(struct task_struct *task);
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struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, struct nameidata *);
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int proc_pid_readdir(struct file * filp, void * dirent, filldir_t filldir);
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unsigned long task_vsize(struct mm_struct *);
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int task_statm(struct mm_struct *, int *, int *, int *, int *);
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char *task_mem(struct mm_struct *, char *);
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void clear_refs_smap(struct mm_struct *mm);
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struct proc_dir_entry *de_get(struct proc_dir_entry *de);
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void de_put(struct proc_dir_entry *de);
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extern struct proc_dir_entry *create_proc_entry(const char *name, mode_t mode,
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struct proc_dir_entry *parent);
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extern void remove_proc_entry(const char *name, struct proc_dir_entry *parent);
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extern struct vfsmount *proc_mnt;
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extern int proc_fill_super(struct super_block *,void *,int);
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extern struct inode *proc_get_inode(struct super_block *, unsigned int, struct proc_dir_entry *);
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/*
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* These are generic /proc routines that use the internal
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* "struct proc_dir_entry" tree to traverse the filesystem.
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*
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* The /proc root directory has extended versions to take care
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* of the /proc/<pid> subdirectories.
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*/
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extern int proc_readdir(struct file *, void *, filldir_t);
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extern struct dentry *proc_lookup(struct inode *, struct dentry *, struct nameidata *);
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extern const struct file_operations proc_kcore_operations;
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extern const struct file_operations proc_kmsg_operations;
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extern const struct file_operations ppc_htab_operations;
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/*
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* proc_tty.c
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*/
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struct tty_driver;
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extern void proc_tty_init(void);
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extern void proc_tty_register_driver(struct tty_driver *driver);
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extern void proc_tty_unregister_driver(struct tty_driver *driver);
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/*
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* proc_devtree.c
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*/
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#ifdef CONFIG_PROC_DEVICETREE
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struct device_node;
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struct property;
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extern void proc_device_tree_init(void);
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extern void proc_device_tree_add_node(struct device_node *, struct proc_dir_entry *);
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extern void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop);
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extern void proc_device_tree_remove_prop(struct proc_dir_entry *pde,
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struct property *prop);
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extern void proc_device_tree_update_prop(struct proc_dir_entry *pde,
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struct property *newprop,
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struct property *oldprop);
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#endif /* CONFIG_PROC_DEVICETREE */
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extern struct proc_dir_entry *proc_symlink(const char *,
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struct proc_dir_entry *, const char *);
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extern struct proc_dir_entry *proc_mkdir(const char *,struct proc_dir_entry *);
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extern struct proc_dir_entry *proc_mkdir_mode(const char *name, mode_t mode,
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struct proc_dir_entry *parent);
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static inline struct proc_dir_entry *create_proc_read_entry(const char *name,
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mode_t mode, struct proc_dir_entry *base,
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read_proc_t *read_proc, void * data)
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{
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struct proc_dir_entry *res=create_proc_entry(name,mode,base);
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if (res) {
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res->read_proc=read_proc;
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res->data=data;
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}
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return res;
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}
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static inline struct proc_dir_entry *create_proc_info_entry(const char *name,
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mode_t mode, struct proc_dir_entry *base, get_info_t *get_info)
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{
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struct proc_dir_entry *res=create_proc_entry(name,mode,base);
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if (res) res->get_info=get_info;
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return res;
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}
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extern struct proc_dir_entry *proc_net_create(struct net *net,
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const char *name, mode_t mode, get_info_t *get_info);
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extern struct proc_dir_entry *proc_net_fops_create(struct net *net,
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const char *name, mode_t mode, const struct file_operations *fops);
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extern void proc_net_remove(struct net *net, const char *name);
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#else
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#define proc_root_driver NULL
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#define proc_bus NULL
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#define proc_net_fops_create(net, name, mode, fops) ({ (void)(mode), NULL; })
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#define proc_net_create(net, name, mode, info) ({ (void)(mode), NULL; })
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static inline void proc_net_remove(struct net *net, const char *name) {}
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static inline void proc_flush_task(struct task_struct *task) { }
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static inline struct proc_dir_entry *create_proc_entry(const char *name,
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mode_t mode, struct proc_dir_entry *parent) { return NULL; }
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#define remove_proc_entry(name, parent) do {} while (0)
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static inline struct proc_dir_entry *proc_symlink(const char *name,
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struct proc_dir_entry *parent,const char *dest) {return NULL;}
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static inline struct proc_dir_entry *proc_mkdir(const char *name,
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struct proc_dir_entry *parent) {return NULL;}
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static inline struct proc_dir_entry *create_proc_read_entry(const char *name,
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mode_t mode, struct proc_dir_entry *base,
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read_proc_t *read_proc, void * data) { return NULL; }
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static inline struct proc_dir_entry *create_proc_info_entry(const char *name,
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mode_t mode, struct proc_dir_entry *base, get_info_t *get_info)
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{ return NULL; }
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struct tty_driver;
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static inline void proc_tty_register_driver(struct tty_driver *driver) {};
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static inline void proc_tty_unregister_driver(struct tty_driver *driver) {};
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extern struct proc_dir_entry proc_root;
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#endif /* CONFIG_PROC_FS */
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#if !defined(CONFIG_PROC_KCORE)
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static inline void kclist_add(struct kcore_list *new, void *addr, size_t size)
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{
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}
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#else
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extern void kclist_add(struct kcore_list *, void *, size_t);
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#endif
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union proc_op {
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int (*proc_get_link)(struct inode *, struct dentry **, struct vfsmount **);
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int (*proc_read)(struct task_struct *task, char *page);
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};
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struct proc_inode {
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struct pid *pid;
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int fd;
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union proc_op op;
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struct proc_dir_entry *pde;
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struct inode vfs_inode;
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};
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static inline struct proc_inode *PROC_I(const struct inode *inode)
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{
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return container_of(inode, struct proc_inode, vfs_inode);
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}
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static inline struct proc_dir_entry *PDE(const struct inode *inode)
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{
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return PROC_I(inode)->pde;
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}
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static inline struct net *PDE_NET(struct proc_dir_entry *pde)
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{
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return pde->parent->data;
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}
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struct net *get_proc_net(const struct inode *inode);
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struct proc_maps_private {
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struct pid *pid;
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struct task_struct *task;
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#ifdef CONFIG_MMU
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struct vm_area_struct *tail_vma;
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#endif
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};
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#endif /* _LINUX_PROC_FS_H */
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