925d1c401f
The kernel implements readlink of /proc/pid/exe by getting the file from the first executable VMA. Then the path to the file is reconstructed and reported as the result. Because of the VMA walk the code is slightly different on nommu systems. This patch avoids separate /proc/pid/exe code on nommu systems. Instead of walking the VMAs to find the first executable file-backed VMA we store a reference to the exec'd file in the mm_struct. That reference would prevent the filesystem holding the executable file from being unmounted even after unmapping the VMAs. So we track the number of VM_EXECUTABLE VMAs and drop the new reference when the last one is unmapped. This avoids pinning the mounted filesystem. [akpm@linux-foundation.org: improve comments] [yamamoto@valinux.co.jp: fix dup_mmap] Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: David Howells <dhowells@redhat.com> Cc:"Eric W. Biederman" <ebiederm@xmission.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
327 lines
9.7 KiB
C
327 lines
9.7 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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/* Worst case buffer size needed for holding an integer. */
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#define PROC_NUMBUF 13
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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 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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void task_mem(struct seq_file *, struct mm_struct *);
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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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struct proc_dir_entry *proc_create(const char *name, mode_t mode,
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struct proc_dir_entry *parent,
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const struct file_operations *proc_fops);
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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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struct pid_namespace;
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extern int proc_fill_super(struct super_block *);
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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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extern int pid_ns_prepare_proc(struct pid_namespace *ns);
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extern void pid_ns_release_proc(struct pid_namespace *ns);
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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_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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extern struct proc_dir_entry *proc_net_mkdir(struct net *net, const char *name,
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struct proc_dir_entry *parent);
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/* While the {get|set|dup}_mm_exe_file functions are for mm_structs, they are
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* only needed to implement /proc/<pid>|self/exe so we define them here. */
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extern void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file);
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extern struct file *get_mm_exe_file(struct mm_struct *mm);
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extern void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm);
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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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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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{
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}
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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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static inline struct proc_dir_entry *proc_create(const char *name,
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mode_t mode, struct proc_dir_entry *parent,
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const struct file_operations *proc_fops)
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{
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return NULL;
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}
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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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static inline int pid_ns_prepare_proc(struct pid_namespace *ns)
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{
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return 0;
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}
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static inline void pid_ns_release_proc(struct pid_namespace *ns)
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{
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}
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static inline void set_mm_exe_file(struct mm_struct *mm,
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struct file *new_exe_file)
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{}
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static inline struct file *get_mm_exe_file(struct mm_struct *mm)
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{
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return NULL;
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}
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static inline void dup_mm_exe_file(struct mm_struct *oldmm,
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struct mm_struct *newmm)
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{}
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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 path *);
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int (*proc_read)(struct task_struct *task, char *page);
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int (*proc_show)(struct seq_file *m,
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struct pid_namespace *ns, struct pid *pid,
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struct task_struct *task);
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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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