// SPDX-License-Identifier: GPL-2.0

  #include <linux/stat.h>
  #include <linux/sysctl.h>

  #include "../fs/xfs/xfs_sysctl.h"

  #include <linux/sunrpc/debug.h>
  #include <linux/string.h>

  #include <linux/syscalls.h>
  #include <linux/namei.h>
  #include <linux/mount.h>
  #include <linux/fs.h>
  #include <linux/nsproxy.h>
  #include <linux/pid_namespace.h>
  #include <linux/file.h>
  #include <linux/ctype.h>

  #include <linux/netdevice.h>

  #include <linux/kernel.h>

  #include <linux/uuid.h>

  #include <linux/slab.h>

  #include <linux/compat.h>

  static ssize_t binary_sysctl(const int *name, int nlen,
  	void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)

  {

  	return -ENOSYS;

  }

  static void deprecated_sysctl_warning(const int *name, int nlen)

  {

  	int i;

  	/*
  	 * CTL_KERN/KERN_VERSION is used by older glibc and cannot
  	 * ever go away.
  	 */

  	if (nlen >= 2 && name[0] == CTL_KERN && name[1] == KERN_VERSION)

  		return;

  	if (printk_ratelimit()) {

  		printk(KERN_INFO
  			"warning: process `%s' used the deprecated sysctl "
  			"system call with ", current->comm);

  		for (i = 0; i < nlen; i++)

  			printk(KERN_CONT "%d.", name[i]);
  		printk(KERN_CONT "
  ");

  	}

  	return;
  }

  #define WARN_ONCE_HASH_BITS 8
  #define WARN_ONCE_HASH_SIZE (1<<WARN_ONCE_HASH_BITS)
  
  static DECLARE_BITMAP(warn_once_bitmap, WARN_ONCE_HASH_SIZE);
  
  #define FNV32_OFFSET 2166136261U
  #define FNV32_PRIME 0x01000193
  
  /*
   * Print each legacy sysctl (approximately) only once.
   * To avoid making the tables non-const use a external
   * hash-table instead.
   * Worst case hash collision: 6, but very rarely.
   * NOTE! We don't use the SMP-safe bit tests. We simply
   * don't care enough.
   */
  static void warn_on_bintable(const int *name, int nlen)
  {
  	int i;
  	u32 hash = FNV32_OFFSET;
  
  	for (i = 0; i < nlen; i++)
  		hash = (hash ^ name[i]) * FNV32_PRIME;
  	hash %= WARN_ONCE_HASH_SIZE;
  	if (__test_and_set_bit(hash, warn_once_bitmap))
  		return;
  	deprecated_sysctl_warning(name, nlen);
  }

  static ssize_t do_sysctl(int __user *args_name, int nlen,
  	void __user *oldval, size_t oldlen, void __user *newval, size_t newlen)

  {
  	int name[CTL_MAXNAME];

  	int i;

  	/* Check args->nlen. */
  	if (nlen < 0 || nlen > CTL_MAXNAME)

  		return -ENOTDIR;

  	/* Read in the sysctl name for simplicity */
  	for (i = 0; i < nlen; i++)
  		if (get_user(name[i], args_name + i))
  			return -EFAULT;

  	warn_on_bintable(name, nlen);

  	return binary_sysctl(name, nlen, oldval, oldlen, newval, newlen);

  }

  SYSCALL_DEFINE1(sysctl, struct __sysctl_args __user *, args)
  {
  	struct __sysctl_args tmp;

  	size_t oldlen = 0;
  	ssize_t result;

  
  	if (copy_from_user(&tmp, args, sizeof(tmp)))
  		return -EFAULT;

  	if (tmp.oldval && !tmp.oldlenp)
  		return -EFAULT;
  
  	if (tmp.oldlenp && get_user(oldlen, tmp.oldlenp))
  		return -EFAULT;
  
  	result = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, oldlen,
  			   tmp.newval, tmp.newlen);
  
  	if (result >= 0) {
  		oldlen = result;
  		result = 0;
  	}

  	if (tmp.oldlenp && put_user(oldlen, tmp.oldlenp))
  		return -EFAULT;
  
  	return result;

  }

  #ifdef CONFIG_COMPAT

  
  struct compat_sysctl_args {
  	compat_uptr_t	name;
  	int		nlen;
  	compat_uptr_t	oldval;
  	compat_uptr_t	oldlenp;
  	compat_uptr_t	newval;
  	compat_size_t	newlen;
  	compat_ulong_t	__unused[4];
  };

  COMPAT_SYSCALL_DEFINE1(sysctl, struct compat_sysctl_args __user *, args)

  {
  	struct compat_sysctl_args tmp;
  	compat_size_t __user *compat_oldlenp;

  	size_t oldlen = 0;
  	ssize_t result;
  
  	if (copy_from_user(&tmp, args, sizeof(tmp)))
  		return -EFAULT;

  	if (tmp.oldval && !tmp.oldlenp)
  		return -EFAULT;

  	compat_oldlenp = compat_ptr(tmp.oldlenp);
  	if (compat_oldlenp && get_user(oldlen, compat_oldlenp))
  		return -EFAULT;

  	result = do_sysctl(compat_ptr(tmp.name), tmp.nlen,

  			   compat_ptr(tmp.oldval), oldlen,

  			   compat_ptr(tmp.newval), tmp.newlen);

  	if (result >= 0) {
  		oldlen = result;
  		result = 0;

  	}

  	if (compat_oldlenp && put_user(oldlen, compat_oldlenp))
  		return -EFAULT;

  	return result;
  }
  
  #endif /* CONFIG_COMPAT */