// SPDX-License-Identifier: GPL-2.0/* *  linux/fs/proc/inode.c * *  Copyright (C) 1991, 1992  Linus Torvalds */ #include <linux/cache.h>#include <linux/time.h>#include <linux/proc_fs.h>#include <linux/kernel.h>#include <linux/pid_namespace.h>#include <linux/mm.h>#include <linux/string.h>#include <linux/stat.h>#include <linux/completion.h>#include <linux/poll.h>#include <linux/printk.h>#include <linux/file.h>#include <linux/limits.h>#include <linux/init.h>#include <linux/module.h>#include <linux/sysctl.h>#include <linux/seq_file.h>#include <linux/slab.h>#include <linux/mount.h>#include <linux/bug.h> #include <linux/uaccess.h> #include "internal.h" static void proc_evict_inode(struct inode *inode){	struct proc_dir_entry *de;	struct ctl_table_header *head;	struct proc_inode *ei = PROC_I(inode); 	truncate_inode_pages_final(&inode->i_data);	clear_inode(inode); 	/* Stop tracking associated processes */	if (ei->pid) {		proc_pid_evict_inode(ei);		ei->pid = NULL;	} 	/* Let go of any associated proc directory entry */	de = ei->pde;	if (de) {		pde_put(de);		ei->pde = NULL;	} 	head = ei->sysctl;	if (head) {		RCU_INIT_POINTER(ei->sysctl, NULL);		proc_sys_evict_inode(inode, head);	}} static struct kmem_cache *proc_inode_cachep __ro_after_init;static struct kmem_cache *pde_opener_cache __ro_after_init; static struct inode *proc_alloc_inode(struct super_block *sb){	struct proc_inode *ei; 	ei = kmem_cache_alloc(proc_inode_cachep, GFP_KERNEL);	if (!ei)		return NULL;	ei->pid = NULL;	ei->fd = 0;	ei->op.proc_get_link = NULL;	ei->pde = NULL;	ei->sysctl = NULL;	ei->sysctl_entry = NULL;	INIT_HLIST_NODE(&ei->sibling_inodes);	ei->ns_ops = NULL;	return &ei->vfs_inode;} static void proc_free_inode(struct inode *inode){	kmem_cache_free(proc_inode_cachep, PROC_I(inode));} static void init_once(void *foo){	struct proc_inode *ei = (struct proc_inode *) foo; 	inode_init_once(&ei->vfs_inode);} void __init proc_init_kmemcache(void){	proc_inode_cachep = kmem_cache_create("proc_inode_cache",					     sizeof(struct proc_inode),					     0, (SLAB_RECLAIM_ACCOUNT|						SLAB_MEM_SPREAD|SLAB_ACCOUNT|						SLAB_PANIC),					     init_once);	pde_opener_cache =		kmem_cache_create("pde_opener", sizeof(struct pde_opener), 0,				  SLAB_ACCOUNT|SLAB_PANIC, NULL);	proc_dir_entry_cache = kmem_cache_create_usercopy(		"proc_dir_entry", SIZEOF_PDE, 0, SLAB_PANIC,		offsetof(struct proc_dir_entry, inline_name),		SIZEOF_PDE_INLINE_NAME, NULL);	BUILD_BUG_ON(sizeof(struct proc_dir_entry) >= SIZEOF_PDE);} void proc_invalidate_siblings_dcache(struct hlist_head *inodes, spinlock_t *lock){	struct inode *inode;	struct proc_inode *ei;	struct hlist_node *node;	struct super_block *old_sb = NULL; 	rcu_read_lock();	for (;;) {		struct super_block *sb;		node = hlist_first_rcu(inodes);		if (!node)			break;		ei = hlist_entry(node, struct proc_inode, sibling_inodes);		spin_lock(lock);		hlist_del_init_rcu(&ei->sibling_inodes);		spin_unlock(lock); 		inode = &ei->vfs_inode;		sb = inode->i_sb;		if ((sb != old_sb) && !atomic_inc_not_zero(&sb->s_active))			continue;		inode = igrab(inode);		rcu_read_unlock();		if (sb != old_sb) {			if (old_sb)				deactivate_super(old_sb);			old_sb = sb;		}		if (unlikely(!inode)) {			rcu_read_lock();			continue;		} 		if (S_ISDIR(inode->i_mode)) {			struct dentry *dir = d_find_any_alias(inode);			if (dir) {				d_invalidate(dir);				dput(dir);			}		} else {			struct dentry *dentry;			while ((dentry = d_find_alias(inode))) {				d_invalidate(dentry);				dput(dentry);			}		}		iput(inode); 		rcu_read_lock();	}	rcu_read_unlock();	if (old_sb)		deactivate_super(old_sb);} static inline const char *hidepid2str(enum proc_hidepid v){	switch (v) {		case HIDEPID_OFF: return "off";		case HIDEPID_NO_ACCESS: return "noaccess";		case HIDEPID_INVISIBLE: return "invisible";		case HIDEPID_NOT_PTRACEABLE: return "ptraceable";	}	WARN_ONCE(1, "bad hide_pid value: %d\n", v);	return "unknown";} static int proc_show_options(struct seq_file *seq, struct dentry *root){	struct proc_fs_info *fs_info = proc_sb_info(root->d_sb); 	if (!gid_eq(fs_info->pid_gid, GLOBAL_ROOT_GID))		seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, fs_info->pid_gid));	if (fs_info->hide_pid != HIDEPID_OFF)		seq_printf(seq, ",hidepid=%s", hidepid2str(fs_info->hide_pid));	if (fs_info->pidonly != PROC_PIDONLY_OFF)		seq_printf(seq, ",subset=pid"); 	return 0;} const struct super_operations proc_sops = {	.alloc_inode	= proc_alloc_inode,	.free_inode	= proc_free_inode,	.drop_inode	= generic_delete_inode,	.evict_inode	= proc_evict_inode,	.statfs		= simple_statfs,	.show_options	= proc_show_options,}; enum {BIAS = -1U<<31}; static inline int use_pde(struct proc_dir_entry *pde){	return likely(atomic_inc_unless_negative(&pde->in_use));} static void unuse_pde(struct proc_dir_entry *pde){	if (unlikely(atomic_dec_return(&pde->in_use) == BIAS))		complete(pde->pde_unload_completion);} /* pde is locked on entry, unlocked on exit */static void close_pdeo(struct proc_dir_entry *pde, struct pde_opener *pdeo)	__releases(&pde->pde_unload_lock){	/*	 * close() (proc_reg_release()) can't delete an entry and proceed:	 * ->release hook needs to be available at the right moment.	 *	 * rmmod (remove_proc_entry() et al) can't delete an entry and proceed:	 * "struct file" needs to be available at the right moment.	 *	 * Therefore, first process to enter this function does ->release() and	 * signals its completion to the other process which does nothing.	 */	if (pdeo->closing) {		/* somebody else is doing that, just wait */		DECLARE_COMPLETION_ONSTACK(c);		pdeo->c = &c;		spin_unlock(&pde->pde_unload_lock);		wait_for_completion(&c);	} else {		struct file *file;		struct completion *c; 		pdeo->closing = true;		spin_unlock(&pde->pde_unload_lock);		file = pdeo->file;		pde->proc_ops->proc_release(file_inode(file), file);		spin_lock(&pde->pde_unload_lock);		/* After ->release. */		list_del(&pdeo->lh);		c = pdeo->c;		spin_unlock(&pde->pde_unload_lock);		if (unlikely(c))			complete(c);		kmem_cache_free(pde_opener_cache, pdeo);	}} void proc_entry_rundown(struct proc_dir_entry *de){	DECLARE_COMPLETION_ONSTACK(c);	/* Wait until all existing callers into module are done. */	de->pde_unload_completion = &c;	if (atomic_add_return(BIAS, &de->in_use) != BIAS)		wait_for_completion(&c); 	/* ->pde_openers list can't grow from now on. */ 	spin_lock(&de->pde_unload_lock);	while (!list_empty(&de->pde_openers)) {		struct pde_opener *pdeo;		pdeo = list_first_entry(&de->pde_openers, struct pde_opener, lh);		close_pdeo(de, pdeo);		spin_lock(&de->pde_unload_lock);	}	spin_unlock(&de->pde_unload_lock);} static loff_t pde_lseek(struct proc_dir_entry *pde, struct file *file, loff_t offset, int whence){	typeof_member(struct proc_ops, proc_lseek) lseek; 	lseek = pde->proc_ops->proc_lseek;	if (!lseek)		lseek = default_llseek;	return lseek(file, offset, whence);} static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence){	struct proc_dir_entry *pde = PDE(file_inode(file));	loff_t rv = -EINVAL; 	if (pde_is_permanent(pde)) {		return pde_lseek(pde, file, offset, whence);	} else if (use_pde(pde)) {		rv = pde_lseek(pde, file, offset, whence);		unuse_pde(pde);	}	return rv;} static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos){	typeof_member(struct proc_ops, proc_read) read; 	read = pde->proc_ops->proc_read;	if (read)		return read(file, buf, count, ppos);	return -EIO;} static ssize_t proc_reg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos){	struct proc_dir_entry *pde = PDE(file_inode(file));	ssize_t rv = -EIO; 	if (pde_is_permanent(pde)) {		return pde_read(pde, file, buf, count, ppos);	} else if (use_pde(pde)) {		rv = pde_read(pde, file, buf, count, ppos);		unuse_pde(pde);	}	return rv;} static ssize_t pde_write(struct proc_dir_entry *pde, struct file *file, const char __user *buf, size_t count, loff_t *ppos){	typeof_member(struct proc_ops, proc_write) write; 	write = pde->proc_ops->proc_write;	if (write)		return write(file, buf, count, ppos);	return -EIO;} static ssize_t proc_reg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos){	struct proc_dir_entry *pde = PDE(file_inode(file));	ssize_t rv = -EIO; 	if (pde_is_permanent(pde)) {		return pde_write(pde, file, buf, count, ppos);	} else if (use_pde(pde)) {		rv = pde_write(pde, file, buf, count, ppos);		unuse_pde(pde);	}	return rv;} static __poll_t pde_poll(struct proc_dir_entry *pde, struct file *file, struct poll_table_struct *pts){	typeof_member(struct proc_ops, proc_poll) poll; 	poll = pde->proc_ops->proc_poll;	if (poll)		return poll(file, pts);	return DEFAULT_POLLMASK;} static __poll_t proc_reg_poll(struct file *file, struct poll_table_struct *pts){	struct proc_dir_entry *pde = PDE(file_inode(file));	__poll_t rv = DEFAULT_POLLMASK; 	if (pde_is_permanent(pde)) {		return pde_poll(pde, file, pts);	} else if (use_pde(pde)) {		rv = pde_poll(pde, file, pts);		unuse_pde(pde);	}	return rv;} static long pde_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg){	typeof_member(struct proc_ops, proc_ioctl) ioctl; 	ioctl = pde->proc_ops->proc_ioctl;	if (ioctl)		return ioctl(file, cmd, arg);	return -ENOTTY;} static long proc_reg_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg){	struct proc_dir_entry *pde = PDE(file_inode(file));	long rv = -ENOTTY; 	if (pde_is_permanent(pde)) {		return pde_ioctl(pde, file, cmd, arg);	} else if (use_pde(pde)) {		rv = pde_ioctl(pde, file, cmd, arg);		unuse_pde(pde);	}	return rv;} #ifdef CONFIG_COMPATstatic long pde_compat_ioctl(struct proc_dir_entry *pde, struct file *file, unsigned int cmd, unsigned long arg){	typeof_member(struct proc_ops, proc_compat_ioctl) compat_ioctl; 	compat_ioctl = pde->proc_ops->proc_compat_ioctl;	if (compat_ioctl)		return compat_ioctl(file, cmd, arg);	return -ENOTTY;} static long proc_reg_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg){	struct proc_dir_entry *pde = PDE(file_inode(file));	long rv = -ENOTTY;	if (pde_is_permanent(pde)) {		return pde_compat_ioctl(pde, file, cmd, arg);	} else if (use_pde(pde)) {		rv = pde_compat_ioctl(pde, file, cmd, arg);		unuse_pde(pde);	}	return rv;}#endif static int pde_mmap(struct proc_dir_entry *pde, struct file *file, struct vm_area_struct *vma){	typeof_member(struct proc_ops, proc_mmap) mmap; 	mmap = pde->proc_ops->proc_mmap;	if (mmap)		return mmap(file, vma);	return -EIO;} static int proc_reg_mmap(struct file *file, struct vm_area_struct *vma){	struct proc_dir_entry *pde = PDE(file_inode(file));	int rv = -EIO; 	if (pde_is_permanent(pde)) {		return pde_mmap(pde, file, vma);	} else if (use_pde(pde)) {		rv = pde_mmap(pde, file, vma);		unuse_pde(pde);	}	return rv;} static unsigned longpde_get_unmapped_area(struct proc_dir_entry *pde, struct file *file, unsigned long orig_addr,			   unsigned long len, unsigned long pgoff,			   unsigned long flags){	typeof_member(struct proc_ops, proc_get_unmapped_area) get_area; 	get_area = pde->proc_ops->proc_get_unmapped_area;#ifdef CONFIG_MMU	if (!get_area)		get_area = current->mm->get_unmapped_area;#endif	if (get_area)		return get_area(file, orig_addr, len, pgoff, flags);	return orig_addr;} static unsigned longproc_reg_get_unmapped_area(struct file *file, unsigned long orig_addr,			   unsigned long len, unsigned long pgoff,			   unsigned long flags){	struct proc_dir_entry *pde = PDE(file_inode(file));	unsigned long rv = -EIO; 	if (pde_is_permanent(pde)) {		return pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);	} else if (use_pde(pde)) {		rv = pde_get_unmapped_area(pde, file, orig_addr, len, pgoff, flags);		unuse_pde(pde);	}	return rv;} static int proc_reg_open(struct inode *inode, struct file *file){	struct proc_fs_info *fs_info = proc_sb_info(inode->i_sb);	struct proc_dir_entry *pde = PDE(inode);	int rv = 0;	typeof_member(struct proc_ops, proc_open) open;	typeof_member(struct proc_ops, proc_release) release;	struct pde_opener *pdeo; 	if (pde_is_permanent(pde)) {		open = pde->proc_ops->proc_open;		if (open)			rv = open(inode, file);		return rv;	} 	if (fs_info->pidonly == PROC_PIDONLY_ON)		return -ENOENT; 	/*	 * Ensure that	 * 1) PDE's ->release hook will be called no matter what

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