801 lines
18 KiB
C
801 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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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/cache.h>
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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/namei.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/bitops.h>
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#include <linux/spinlock.h>
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#include <linux/completion.h>
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#include <linux/uaccess.h>
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#include <linux/seq_file.h>
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#include "internal.h"
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static DEFINE_RWLOCK(proc_subdir_lock);
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struct kmem_cache *proc_dir_entry_cache __ro_after_init;
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void pde_free(struct proc_dir_entry *pde)
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{
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if (S_ISLNK(pde->mode))
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kfree(pde->data);
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if (pde->name != pde->inline_name)
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kfree(pde->name);
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kmem_cache_free(proc_dir_entry_cache, pde);
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}
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static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
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{
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if (len < de->namelen)
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return -1;
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if (len > de->namelen)
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return 1;
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return memcmp(name, de->name, len);
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}
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static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
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{
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return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
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subdir_node);
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}
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static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
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{
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return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
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subdir_node);
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}
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static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
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const char *name,
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unsigned int len)
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{
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struct rb_node *node = dir->subdir.rb_node;
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while (node) {
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struct proc_dir_entry *de = rb_entry(node,
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struct proc_dir_entry,
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subdir_node);
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int result = proc_match(name, de, len);
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if (result < 0)
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node = node->rb_left;
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else if (result > 0)
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node = node->rb_right;
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else
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return de;
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}
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return NULL;
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}
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static bool pde_subdir_insert(struct proc_dir_entry *dir,
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struct proc_dir_entry *de)
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{
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struct rb_root *root = &dir->subdir;
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struct rb_node **new = &root->rb_node, *parent = NULL;
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/* Figure out where to put new node */
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while (*new) {
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struct proc_dir_entry *this = rb_entry(*new,
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struct proc_dir_entry,
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subdir_node);
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int result = proc_match(de->name, this, de->namelen);
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parent = *new;
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if (result < 0)
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new = &(*new)->rb_left;
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else if (result > 0)
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new = &(*new)->rb_right;
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else
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return false;
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}
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/* Add new node and rebalance tree. */
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rb_link_node(&de->subdir_node, parent, new);
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rb_insert_color(&de->subdir_node, root);
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return true;
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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 = d_inode(dentry);
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struct proc_dir_entry *de = PDE(inode);
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int error;
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error = setattr_prepare(dentry, 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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proc_set_user(de, inode->i_uid, 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(const struct path *path, struct kstat *stat,
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u32 request_mask, unsigned int query_flags)
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{
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struct inode *inode = d_inode(path->dentry);
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struct proc_dir_entry *de = PDE(inode);
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if (de) {
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nlink_t nlink = READ_ONCE(de->nlink);
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if (nlink > 0) {
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set_nlink(inode, nlink);
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}
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}
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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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de = pde_subdir_find(de, cp, len);
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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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read_lock(&proc_subdir_lock);
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rv = __xlate_proc_name(name, ret, residual);
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read_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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#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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int i;
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i = ida_simple_get(&proc_inum_ida, 0, UINT_MAX - PROC_DYNAMIC_FIRST + 1,
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GFP_KERNEL);
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if (i < 0)
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return i;
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*inum = PROC_DYNAMIC_FIRST + (unsigned int)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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ida_simple_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST);
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}
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static int proc_misc_d_revalidate(struct dentry *dentry, unsigned int flags)
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{
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if (flags & LOOKUP_RCU)
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return -ECHILD;
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if (atomic_read(&PDE(d_inode(dentry))->in_use) < 0)
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return 0; /* revalidate */
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return 1;
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}
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static int proc_misc_d_delete(const struct dentry *dentry)
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{
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return atomic_read(&PDE(d_inode(dentry))->in_use) < 0;
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}
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static const struct dentry_operations proc_misc_dentry_ops = {
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.d_revalidate = proc_misc_d_revalidate,
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.d_delete = proc_misc_d_delete,
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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 inode *dir, struct dentry *dentry,
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struct proc_dir_entry *de)
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{
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struct inode *inode;
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read_lock(&proc_subdir_lock);
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de = pde_subdir_find(de, dentry->d_name.name, dentry->d_name.len);
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if (de) {
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pde_get(de);
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read_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, de->proc_dops);
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return d_splice_alias(inode, dentry);
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}
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read_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(dir, dentry, PDE(dir));
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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 file *file, struct dir_context *ctx,
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struct proc_dir_entry *de)
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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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i = ctx->pos - 2;
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read_lock(&proc_subdir_lock);
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de = pde_subdir_first(de);
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for (;;) {
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if (!de) {
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read_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 = pde_subdir_next(de);
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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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read_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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ctx->pos++;
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read_lock(&proc_subdir_lock);
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next = pde_subdir_next(de);
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pde_put(de);
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de = next;
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} while (de);
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read_unlock(&proc_subdir_lock);
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return 1;
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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(file, ctx, PDE(inode));
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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_shared = proc_readdir,
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};
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static int proc_net_d_revalidate(struct dentry *dentry, unsigned int flags)
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{
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return 0;
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}
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const struct dentry_operations proc_net_dentry_ops = {
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.d_revalidate = proc_net_d_revalidate,
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.d_delete = always_delete_dentry,
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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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/* returns the registered entry, or frees dp and returns NULL on failure */
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struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
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struct proc_dir_entry *dp)
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{
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if (proc_alloc_inum(&dp->low_ino))
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goto out_free_entry;
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write_lock(&proc_subdir_lock);
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dp->parent = dir;
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if (pde_subdir_insert(dir, dp) == false) {
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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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write_unlock(&proc_subdir_lock);
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goto out_free_inum;
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}
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dir->nlink++;
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write_unlock(&proc_subdir_lock);
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return dp;
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out_free_inum:
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proc_free_inum(dp->low_ino);
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out_free_entry:
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pde_free(dp);
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return NULL;
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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;
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struct qstr qstr;
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if (xlate_proc_name(name, parent, &fn) != 0)
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goto out;
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qstr.name = fn;
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qstr.len = strlen(fn);
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if (qstr.len == 0 || qstr.len >= 256) {
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WARN(1, "name len %u\n", qstr.len);
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return NULL;
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}
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if (qstr.len == 1 && fn[0] == '.') {
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WARN(1, "name '.'\n");
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return NULL;
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}
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if (qstr.len == 2 && fn[0] == '.' && fn[1] == '.') {
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WARN(1, "name '..'\n");
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return NULL;
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}
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if (*parent == &proc_root && name_to_int(&qstr) != ~0U) {
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WARN(1, "create '/proc/%s' by hand\n", qstr.name);
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return NULL;
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}
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if (is_empty_pde(*parent)) {
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WARN(1, "attempt to add to permanently empty directory");
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return NULL;
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}
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ent = kmem_cache_zalloc(proc_dir_entry_cache, GFP_KERNEL);
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if (!ent)
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goto out;
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if (qstr.len + 1 <= SIZEOF_PDE_INLINE_NAME) {
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ent->name = ent->inline_name;
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} else {
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ent->name = kmalloc(qstr.len + 1, GFP_KERNEL);
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if (!ent->name) {
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pde_free(ent);
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return NULL;
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}
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}
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memcpy(ent->name, fn, qstr.len + 1);
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ent->namelen = qstr.len;
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ent->mode = mode;
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ent->nlink = nlink;
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ent->subdir = RB_ROOT;
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refcount_set(&ent->refcnt, 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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proc_set_user(ent, (*parent)->uid, (*parent)->gid);
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ent->proc_dops = &proc_misc_dentry_ops;
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/* Revalidate everything under /proc/${pid}/net */
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if ((*parent)->proc_dops == &proc_net_dentry_ops)
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pde_force_lookup(ent);
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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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ent->proc_iops = &proc_link_inode_operations;
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ent = proc_register(parent, ent);
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} else {
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pde_free(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(const char *name, umode_t mode,
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struct proc_dir_entry *parent, void *data, bool force_lookup)
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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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ent->proc_fops = &proc_dir_operations;
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ent->proc_iops = &proc_dir_inode_operations;
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if (force_lookup) {
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pde_force_lookup(ent);
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}
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ent = proc_register(parent, ent);
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}
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return ent;
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}
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EXPORT_SYMBOL_GPL(_proc_mkdir);
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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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return _proc_mkdir(name, mode, parent, data, false);
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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_mount_point(const char *name)
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{
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umode_t mode = S_IFDIR | S_IRUGO | S_IXUGO;
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struct proc_dir_entry *ent, *parent = NULL;
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ent = __proc_create(&parent, name, mode, 2);
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if (ent) {
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ent->data = NULL;
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ent->proc_fops = NULL;
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ent->proc_iops = NULL;
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ent = proc_register(parent, ent);
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}
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return ent;
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}
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EXPORT_SYMBOL(proc_create_mount_point);
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|
|
|
struct proc_dir_entry *proc_create_reg(const char *name, umode_t mode,
|
|
struct proc_dir_entry **parent, void *data)
|
|
{
|
|
struct proc_dir_entry *p;
|
|
|
|
if ((mode & S_IFMT) == 0)
|
|
mode |= S_IFREG;
|
|
if ((mode & S_IALLUGO) == 0)
|
|
mode |= S_IRUGO;
|
|
if (WARN_ON_ONCE(!S_ISREG(mode)))
|
|
return NULL;
|
|
|
|
p = __proc_create(parent, name, mode, 1);
|
|
if (p) {
|
|
p->proc_iops = &proc_file_inode_operations;
|
|
p->data = data;
|
|
}
|
|
return p;
|
|
}
|
|
|
|
struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
|
|
struct proc_dir_entry *parent,
|
|
const struct file_operations *proc_fops, void *data)
|
|
{
|
|
struct proc_dir_entry *p;
|
|
|
|
BUG_ON(proc_fops == NULL);
|
|
|
|
p = proc_create_reg(name, mode, &parent, data);
|
|
if (!p)
|
|
return NULL;
|
|
p->proc_fops = proc_fops;
|
|
return proc_register(parent, p);
|
|
}
|
|
EXPORT_SYMBOL(proc_create_data);
|
|
|
|
struct proc_dir_entry *proc_create(const char *name, umode_t mode,
|
|
struct proc_dir_entry *parent,
|
|
const struct file_operations *proc_fops)
|
|
{
|
|
return proc_create_data(name, mode, parent, proc_fops, NULL);
|
|
}
|
|
EXPORT_SYMBOL(proc_create);
|
|
|
|
static int proc_seq_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
if (de->state_size)
|
|
return seq_open_private(file, de->seq_ops, de->state_size);
|
|
return seq_open(file, de->seq_ops);
|
|
}
|
|
|
|
static int proc_seq_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
if (de->state_size)
|
|
return seq_release_private(inode, file);
|
|
return seq_release(inode, file);
|
|
}
|
|
|
|
static const struct file_operations proc_seq_fops = {
|
|
.open = proc_seq_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = proc_seq_release,
|
|
};
|
|
|
|
struct proc_dir_entry *proc_create_seq_private(const char *name, umode_t mode,
|
|
struct proc_dir_entry *parent, const struct seq_operations *ops,
|
|
unsigned int state_size, void *data)
|
|
{
|
|
struct proc_dir_entry *p;
|
|
|
|
p = proc_create_reg(name, mode, &parent, data);
|
|
if (!p)
|
|
return NULL;
|
|
p->proc_fops = &proc_seq_fops;
|
|
p->seq_ops = ops;
|
|
p->state_size = state_size;
|
|
return proc_register(parent, p);
|
|
}
|
|
EXPORT_SYMBOL(proc_create_seq_private);
|
|
|
|
static int proc_single_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct proc_dir_entry *de = PDE(inode);
|
|
|
|
return single_open(file, de->single_show, de->data);
|
|
}
|
|
|
|
static const struct file_operations proc_single_fops = {
|
|
.open = proc_single_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = single_release,
|
|
};
|
|
|
|
struct proc_dir_entry *proc_create_single_data(const char *name, umode_t mode,
|
|
struct proc_dir_entry *parent,
|
|
int (*show)(struct seq_file *, void *), void *data)
|
|
{
|
|
struct proc_dir_entry *p;
|
|
|
|
p = proc_create_reg(name, mode, &parent, data);
|
|
if (!p)
|
|
return NULL;
|
|
p->proc_fops = &proc_single_fops;
|
|
p->single_show = show;
|
|
return proc_register(parent, p);
|
|
}
|
|
EXPORT_SYMBOL(proc_create_single_data);
|
|
|
|
void proc_set_size(struct proc_dir_entry *de, loff_t size)
|
|
{
|
|
de->size = size;
|
|
}
|
|
EXPORT_SYMBOL(proc_set_size);
|
|
|
|
void proc_set_user(struct proc_dir_entry *de, kuid_t uid, kgid_t gid)
|
|
{
|
|
de->uid = uid;
|
|
de->gid = gid;
|
|
}
|
|
EXPORT_SYMBOL(proc_set_user);
|
|
|
|
void pde_put(struct proc_dir_entry *pde)
|
|
{
|
|
if (refcount_dec_and_test(&pde->refcnt)) {
|
|
proc_free_inum(pde->low_ino);
|
|
pde_free(pde);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Remove a /proc entry and free it if it's not currently in use.
|
|
*/
|
|
void remove_proc_entry(const char *name, struct proc_dir_entry *parent)
|
|
{
|
|
struct proc_dir_entry *de = NULL;
|
|
const char *fn = name;
|
|
unsigned int len;
|
|
|
|
write_lock(&proc_subdir_lock);
|
|
if (__xlate_proc_name(name, &parent, &fn) != 0) {
|
|
write_unlock(&proc_subdir_lock);
|
|
return;
|
|
}
|
|
len = strlen(fn);
|
|
|
|
de = pde_subdir_find(parent, fn, len);
|
|
if (de) {
|
|
rb_erase(&de->subdir_node, &parent->subdir);
|
|
if (S_ISDIR(de->mode)) {
|
|
parent->nlink--;
|
|
}
|
|
}
|
|
write_unlock(&proc_subdir_lock);
|
|
if (!de) {
|
|
WARN(1, "name '%s'\n", name);
|
|
return;
|
|
}
|
|
|
|
proc_entry_rundown(de);
|
|
|
|
WARN(pde_subdir_first(de),
|
|
"%s: removing non-empty directory '%s/%s', leaking at least '%s'\n",
|
|
__func__, de->parent->name, de->name, pde_subdir_first(de)->name);
|
|
pde_put(de);
|
|
}
|
|
EXPORT_SYMBOL(remove_proc_entry);
|
|
|
|
int remove_proc_subtree(const char *name, struct proc_dir_entry *parent)
|
|
{
|
|
struct proc_dir_entry *root = NULL, *de, *next;
|
|
const char *fn = name;
|
|
unsigned int len;
|
|
|
|
write_lock(&proc_subdir_lock);
|
|
if (__xlate_proc_name(name, &parent, &fn) != 0) {
|
|
write_unlock(&proc_subdir_lock);
|
|
return -ENOENT;
|
|
}
|
|
len = strlen(fn);
|
|
|
|
root = pde_subdir_find(parent, fn, len);
|
|
if (!root) {
|
|
write_unlock(&proc_subdir_lock);
|
|
return -ENOENT;
|
|
}
|
|
rb_erase(&root->subdir_node, &parent->subdir);
|
|
|
|
de = root;
|
|
while (1) {
|
|
next = pde_subdir_first(de);
|
|
if (next) {
|
|
rb_erase(&next->subdir_node, &de->subdir);
|
|
de = next;
|
|
continue;
|
|
}
|
|
next = de->parent;
|
|
if (S_ISDIR(de->mode))
|
|
next->nlink--;
|
|
write_unlock(&proc_subdir_lock);
|
|
|
|
proc_entry_rundown(de);
|
|
if (de == root)
|
|
break;
|
|
pde_put(de);
|
|
|
|
write_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);
|
|
|
|
/*
|
|
* Pull a user buffer into memory and pass it to the file's write handler if
|
|
* one is supplied. The ->write() method is permitted to modify the
|
|
* kernel-side buffer.
|
|
*/
|
|
ssize_t proc_simple_write(struct file *f, const char __user *ubuf, size_t size,
|
|
loff_t *_pos)
|
|
{
|
|
struct proc_dir_entry *pde = PDE(file_inode(f));
|
|
char *buf;
|
|
int ret;
|
|
|
|
if (!pde->write)
|
|
return -EACCES;
|
|
if (size == 0 || size > PAGE_SIZE - 1)
|
|
return -EINVAL;
|
|
buf = memdup_user_nul(ubuf, size);
|
|
if (IS_ERR(buf))
|
|
return PTR_ERR(buf);
|
|
ret = pde->write(f, buf, size);
|
|
kfree(buf);
|
|
return ret == 0 ? size : ret;
|
|
}
|