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616 lines
13 KiB
C
616 lines
13 KiB
C
/*
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* proc/fs/generic.c --- generic routines for the proc-fs
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*
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* This file contains generic proc-fs routines for handling
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* directories and files.
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*
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* Copyright (C) 1991, 1992 Linus Torvalds.
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* Copyright (C) 1997 Theodore Ts'o
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*/
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/proc_fs.h>
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#include <linux/stat.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/printk.h>
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#include <linux/mount.h>
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#include <linux/init.h>
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#include <linux/idr.h>
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#include <linux/namei.h>
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#include <linux/bitops.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <asm/uaccess.h>
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#include "internal.h"
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DEFINE_SPINLOCK(proc_subdir_lock);
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static int proc_match(unsigned int len, const char *name, struct proc_dir_entry *de)
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{
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if (de->namelen != len)
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return 0;
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return !memcmp(name, de->name, len);
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}
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static int proc_notify_change(struct dentry *dentry, struct iattr *iattr)
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{
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struct inode *inode = dentry->d_inode;
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struct proc_dir_entry *de = PDE(inode);
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int error;
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error = inode_change_ok(inode, iattr);
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if (error)
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return error;
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setattr_copy(inode, iattr);
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mark_inode_dirty(inode);
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de->uid = inode->i_uid;
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de->gid = inode->i_gid;
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de->mode = inode->i_mode;
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return 0;
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}
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static int proc_getattr(struct vfsmount *mnt, struct dentry *dentry,
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struct kstat *stat)
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{
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struct inode *inode = dentry->d_inode;
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struct proc_dir_entry *de = PROC_I(inode)->pde;
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if (de && de->nlink)
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set_nlink(inode, de->nlink);
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generic_fillattr(inode, stat);
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return 0;
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}
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static const struct inode_operations proc_file_inode_operations = {
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.setattr = proc_notify_change,
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};
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/*
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* This function parses a name such as "tty/driver/serial", and
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* returns the struct proc_dir_entry for "/proc/tty/driver", and
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* returns "serial" in residual.
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*/
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static int __xlate_proc_name(const char *name, struct proc_dir_entry **ret,
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const char **residual)
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{
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const char *cp = name, *next;
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struct proc_dir_entry *de;
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unsigned int len;
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de = *ret;
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if (!de)
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de = &proc_root;
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while (1) {
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next = strchr(cp, '/');
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if (!next)
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break;
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len = next - cp;
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for (de = de->subdir; de ; de = de->next) {
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if (proc_match(len, cp, de))
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break;
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}
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if (!de) {
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WARN(1, "name '%s'\n", name);
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return -ENOENT;
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}
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cp += len + 1;
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}
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*residual = cp;
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*ret = de;
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return 0;
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}
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static int xlate_proc_name(const char *name, struct proc_dir_entry **ret,
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const char **residual)
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{
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int rv;
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spin_lock(&proc_subdir_lock);
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rv = __xlate_proc_name(name, ret, residual);
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spin_unlock(&proc_subdir_lock);
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return rv;
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}
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static DEFINE_IDA(proc_inum_ida);
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static DEFINE_SPINLOCK(proc_inum_lock); /* protects the above */
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#define PROC_DYNAMIC_FIRST 0xF0000000U
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/*
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* Return an inode number between PROC_DYNAMIC_FIRST and
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* 0xffffffff, or zero on failure.
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*/
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int proc_alloc_inum(unsigned int *inum)
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{
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unsigned int i;
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int error;
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retry:
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if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL))
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return -ENOMEM;
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spin_lock_irq(&proc_inum_lock);
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error = ida_get_new(&proc_inum_ida, &i);
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spin_unlock_irq(&proc_inum_lock);
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if (error == -EAGAIN)
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goto retry;
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else if (error)
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return error;
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if (i > UINT_MAX - PROC_DYNAMIC_FIRST) {
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spin_lock_irq(&proc_inum_lock);
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ida_remove(&proc_inum_ida, i);
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spin_unlock_irq(&proc_inum_lock);
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return -ENOSPC;
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}
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*inum = PROC_DYNAMIC_FIRST + i;
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return 0;
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}
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void proc_free_inum(unsigned int inum)
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{
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unsigned long flags;
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spin_lock_irqsave(&proc_inum_lock, flags);
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ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
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spin_unlock_irqrestore(&proc_inum_lock, flags);
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}
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static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd)
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{
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nd_set_link(nd, __PDE_DATA(dentry->d_inode));
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return NULL;
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}
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static const struct inode_operations proc_link_inode_operations = {
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.readlink = generic_readlink,
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.follow_link = proc_follow_link,
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};
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/*
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* As some entries in /proc are volatile, we want to
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* get rid of unused dentries. This could be made
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* smarter: we could keep a "volatile" flag in the
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* inode to indicate which ones to keep.
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*/
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static int proc_delete_dentry(const struct dentry * dentry)
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{
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return 1;
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}
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static const struct dentry_operations proc_dentry_operations =
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{
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.d_delete = proc_delete_dentry,
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};
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/*
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* Don't create negative dentries here, return -ENOENT by hand
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* instead.
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*/
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struct dentry *proc_lookup_de(struct proc_dir_entry *de, struct inode *dir,
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struct dentry *dentry)
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{
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struct inode *inode;
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spin_lock(&proc_subdir_lock);
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for (de = de->subdir; de ; de = de->next) {
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if (de->namelen != dentry->d_name.len)
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continue;
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if (!memcmp(dentry->d_name.name, de->name, de->namelen)) {
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pde_get(de);
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spin_unlock(&proc_subdir_lock);
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inode = proc_get_inode(dir->i_sb, de);
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if (!inode)
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return ERR_PTR(-ENOMEM);
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d_set_d_op(dentry, &proc_dentry_operations);
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d_add(dentry, inode);
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return NULL;
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}
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}
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spin_unlock(&proc_subdir_lock);
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return ERR_PTR(-ENOENT);
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}
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struct dentry *proc_lookup(struct inode *dir, struct dentry *dentry,
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unsigned int flags)
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{
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return proc_lookup_de(PDE(dir), dir, dentry);
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}
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/*
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* This returns non-zero if at EOF, so that the /proc
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* root directory can use this and check if it should
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* continue with the <pid> entries..
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*
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* Note that the VFS-layer doesn't care about the return
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* value of the readdir() call, as long as it's non-negative
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* for success..
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*/
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int proc_readdir_de(struct proc_dir_entry *de, struct file *file,
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struct dir_context *ctx)
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{
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int i;
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if (!dir_emit_dots(file, ctx))
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return 0;
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spin_lock(&proc_subdir_lock);
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de = de->subdir;
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i = ctx->pos - 2;
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for (;;) {
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if (!de) {
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spin_unlock(&proc_subdir_lock);
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return 0;
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}
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if (!i)
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break;
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de = de->next;
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i--;
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}
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do {
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struct proc_dir_entry *next;
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pde_get(de);
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spin_unlock(&proc_subdir_lock);
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if (!dir_emit(ctx, de->name, de->namelen,
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de->low_ino, de->mode >> 12)) {
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pde_put(de);
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return 0;
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}
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spin_lock(&proc_subdir_lock);
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ctx->pos++;
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next = de->next;
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pde_put(de);
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de = next;
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} while (de);
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spin_unlock(&proc_subdir_lock);
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return 0;
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}
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int proc_readdir(struct file *file, struct dir_context *ctx)
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{
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struct inode *inode = file_inode(file);
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return proc_readdir_de(PDE(inode), file, ctx);
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}
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/*
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* These are the generic /proc directory operations. They
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* use the in-memory "struct proc_dir_entry" tree to parse
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* the /proc directory.
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*/
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static const struct file_operations proc_dir_operations = {
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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.iterate = proc_readdir,
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};
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/*
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* proc directories can do almost nothing..
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*/
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static const struct inode_operations proc_dir_inode_operations = {
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.lookup = proc_lookup,
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.getattr = proc_getattr,
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.setattr = proc_notify_change,
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};
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static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
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{
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struct proc_dir_entry *tmp;
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int ret;
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ret = proc_alloc_inum(&dp->low_ino);
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if (ret)
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return ret;
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if (S_ISDIR(dp->mode)) {
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dp->proc_fops = &proc_dir_operations;
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dp->proc_iops = &proc_dir_inode_operations;
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dir->nlink++;
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} else if (S_ISLNK(dp->mode)) {
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dp->proc_iops = &proc_link_inode_operations;
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} else if (S_ISREG(dp->mode)) {
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BUG_ON(dp->proc_fops == NULL);
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dp->proc_iops = &proc_file_inode_operations;
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} else {
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WARN_ON(1);
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return -EINVAL;
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}
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spin_lock(&proc_subdir_lock);
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for (tmp = dir->subdir; tmp; tmp = tmp->next)
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if (strcmp(tmp->name, dp->name) == 0) {
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WARN(1, "proc_dir_entry '%s/%s' already registered\n",
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dir->name, dp->name);
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break;
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}
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dp->next = dir->subdir;
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dp->parent = dir;
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dir->subdir = dp;
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spin_unlock(&proc_subdir_lock);
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return 0;
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}
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static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
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const char *name,
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umode_t mode,
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nlink_t nlink)
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{
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struct proc_dir_entry *ent = NULL;
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const char *fn = name;
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unsigned int len;
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/* make sure name is valid */
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if (!name || !strlen(name))
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goto out;
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if (xlate_proc_name(name, parent, &fn) != 0)
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goto out;
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/* At this point there must not be any '/' characters beyond *fn */
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if (strchr(fn, '/'))
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goto out;
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len = strlen(fn);
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ent = kzalloc(sizeof(struct proc_dir_entry) + len + 1, GFP_KERNEL);
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if (!ent)
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goto out;
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memcpy(ent->name, fn, len + 1);
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ent->namelen = len;
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ent->mode = mode;
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ent->nlink = nlink;
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atomic_set(&ent->count, 1);
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spin_lock_init(&ent->pde_unload_lock);
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INIT_LIST_HEAD(&ent->pde_openers);
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out:
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return ent;
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}
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struct proc_dir_entry *proc_symlink(const char *name,
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struct proc_dir_entry *parent, const char *dest)
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{
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struct proc_dir_entry *ent;
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ent = __proc_create(&parent, name,
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(S_IFLNK | S_IRUGO | S_IWUGO | S_IXUGO),1);
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if (ent) {
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ent->data = kmalloc((ent->size=strlen(dest))+1, GFP_KERNEL);
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if (ent->data) {
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strcpy((char*)ent->data,dest);
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if (proc_register(parent, ent) < 0) {
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kfree(ent->data);
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kfree(ent);
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ent = NULL;
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}
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} else {
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kfree(ent);
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ent = NULL;
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}
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}
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return ent;
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}
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EXPORT_SYMBOL(proc_symlink);
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struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
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struct proc_dir_entry *parent, void *data)
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{
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struct proc_dir_entry *ent;
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if (mode == 0)
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mode = S_IRUGO | S_IXUGO;
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ent = __proc_create(&parent, name, S_IFDIR | mode, 2);
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if (ent) {
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ent->data = data;
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if (proc_register(parent, ent) < 0) {
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kfree(ent);
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ent = NULL;
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}
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}
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return ent;
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}
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EXPORT_SYMBOL_GPL(proc_mkdir_data);
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struct proc_dir_entry *proc_mkdir_mode(const char *name, umode_t mode,
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struct proc_dir_entry *parent)
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{
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return proc_mkdir_data(name, mode, parent, NULL);
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}
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EXPORT_SYMBOL(proc_mkdir_mode);
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struct proc_dir_entry *proc_mkdir(const char *name,
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struct proc_dir_entry *parent)
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{
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return proc_mkdir_data(name, 0, parent, NULL);
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}
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EXPORT_SYMBOL(proc_mkdir);
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struct proc_dir_entry *proc_create_data(const char *name, umode_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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void *data)
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{
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struct proc_dir_entry *pde;
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if ((mode & S_IFMT) == 0)
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mode |= S_IFREG;
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if (!S_ISREG(mode)) {
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WARN_ON(1); /* use proc_mkdir() */
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return NULL;
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}
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if ((mode & S_IALLUGO) == 0)
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mode |= S_IRUGO;
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pde = __proc_create(&parent, name, mode, 1);
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if (!pde)
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goto out;
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pde->proc_fops = proc_fops;
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pde->data = data;
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if (proc_register(parent, pde) < 0)
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goto out_free;
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return pde;
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out_free:
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kfree(pde);
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out:
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return NULL;
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}
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EXPORT_SYMBOL(proc_create_data);
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void proc_set_size(struct proc_dir_entry *de, loff_t size)
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{
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de->size = size;
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}
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EXPORT_SYMBOL(proc_set_size);
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void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
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{
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de->uid = uid;
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de->gid = gid;
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}
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EXPORT_SYMBOL(proc_set_user);
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static void free_proc_entry(struct proc_dir_entry *de)
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{
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proc_free_inum(de->low_ino);
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if (S_ISLNK(de->mode))
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kfree(de->data);
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kfree(de);
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}
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void pde_put(struct proc_dir_entry *pde)
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{
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if (atomic_dec_and_test(&pde->count))
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free_proc_entry(pde);
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}
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/*
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* Remove a /proc entry and free it if it's not currently in use.
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*/
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void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
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{
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struct proc_dir_entry **p;
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struct proc_dir_entry *de = NULL;
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const char *fn = name;
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unsigned int len;
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spin_lock(&proc_subdir_lock);
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if (__xlate_proc_name(name, &parent, &fn) != 0) {
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spin_unlock(&proc_subdir_lock);
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return;
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}
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len = strlen(fn);
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for (p = &parent->subdir; *p; p=&(*p)->next ) {
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if (proc_match(len, fn, *p)) {
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de = *p;
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*p = de->next;
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de->next = NULL;
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break;
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}
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}
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spin_unlock(&proc_subdir_lock);
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if (!de) {
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WARN(1, "name '%s'\n", name);
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return;
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}
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proc_entry_rundown(de);
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if (S_ISDIR(de->mode))
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parent->nlink--;
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de->nlink = 0;
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WARN(de->subdir, "%s: removing non-empty directory "
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"'%s/%s', leaking at least '%s'\n", __func__,
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de->parent->name, de->name, de->subdir->name);
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pde_put(de);
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}
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EXPORT_SYMBOL(remove_proc_entry);
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int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
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{
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struct proc_dir_entry **p;
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struct proc_dir_entry *root = NULL, *de, *next;
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const char *fn = name;
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unsigned int len;
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|
|
spin_lock(&proc_subdir_lock);
|
|
if (__xlate_proc_name(name, &parent, &fn) != 0) {
|
|
spin_unlock(&proc_subdir_lock);
|
|
return -ENOENT;
|
|
}
|
|
len = strlen(fn);
|
|
|
|
for (p = &parent->subdir; *p; p=&(*p)->next ) {
|
|
if (proc_match(len, fn, *p)) {
|
|
root = *p;
|
|
*p = root->next;
|
|
root->next = NULL;
|
|
break;
|
|
}
|
|
}
|
|
if (!root) {
|
|
spin_unlock(&proc_subdir_lock);
|
|
return -ENOENT;
|
|
}
|
|
de = root;
|
|
while (1) {
|
|
next = de->subdir;
|
|
if (next) {
|
|
de->subdir = next->next;
|
|
next->next = NULL;
|
|
de = next;
|
|
continue;
|
|
}
|
|
spin_unlock(&proc_subdir_lock);
|
|
|
|
proc_entry_rundown(de);
|
|
next = de->parent;
|
|
if (S_ISDIR(de->mode))
|
|
next->nlink--;
|
|
de->nlink = 0;
|
|
if (de == root)
|
|
break;
|
|
pde_put(de);
|
|
|
|
spin_lock(&proc_subdir_lock);
|
|
de = next;
|
|
}
|
|
pde_put(root);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(remove_proc_subtree);
|
|
|
|
void *proc_get_parent_data(const struct inode *inode)
|
|
{
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
return de->parent->data;
|
|
}
|
|
EXPORT_SYMBOL_GPL(proc_get_parent_data);
|
|
|
|
void proc_remove(struct proc_dir_entry *de)
|
|
{
|
|
if (de)
|
|
remove_proc_subtree(de->name, de->parent);
|
|
}
|
|
EXPORT_SYMBOL(proc_remove);
|
|
|
|
void *PDE_DATA(const struct inode *inode)
|
|
{
|
|
return __PDE_DATA(inode);
|
|
}
|
|
EXPORT_SYMBOL(PDE_DATA);
|