generic.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * proc/fs/generic.c --- generic routines for the proc-fs
 *
 * This file contains generic proc-fs routines for handling
 * directories and files.
 * 
 * Copyright (C) 1991, 1992 Linus Torvalds.
 * Copyright (C) 1997 Theodore Ts'o
 */

#include <linux/cache.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <linux/printk.h>
#include <linux/mount.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>

#include "internal.h"

static DEFINE_RWLOCK(proc_subdir_lock);

struct kmem_cache *proc_dir_entry_cache __ro_after_init;

void pde_free(struct proc_dir_entry *pde)
{
	if (S_ISLNK(pde->mode))
		kfree(pde->data);
	if (pde->name != pde->inline_name)
		kfree(pde->name);
	kmem_cache_free(proc_dir_entry_cache, pde);
}

static int proc_match(const char *name, struct proc_dir_entry *de, unsigned int len)
{
	if (len < de->namelen)
		return -1;
	if (len > de->namelen)
		return 1;

	return memcmp(name, de->name, len);
}

static struct proc_dir_entry *pde_subdir_first(struct proc_dir_entry *dir)
{
	return rb_entry_safe(rb_first(&dir->subdir), struct proc_dir_entry,
			     subdir_node);
}

static struct proc_dir_entry *pde_subdir_next(struct proc_dir_entry *dir)
{
	return rb_entry_safe(rb_next(&dir->subdir_node), struct proc_dir_entry,
			     subdir_node);
}

static struct proc_dir_entry *pde_subdir_find(struct proc_dir_entry *dir,
					      const char *name,
					      unsigned int len)