/*
 * sysctl.c: General linux system control interface
 *
 * Begun 24 March 1995, Stephen Tweedie
 * Added /proc support, Dec 1995
 * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
 * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
 * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
 * Dynamic registration fixes, Stephen Tweedie.
 * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
 * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
 *  Horn.
 * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
 * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
 * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
 *  Wendling.
 * The list_for_each() macro wasn't appropriate for the sysctl loop.
 *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
 */

#include <linux/config.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
#include <linux/ctype.h>
#include <linux/utsname.h>
#include <linux/capability.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sysrq.h>
#include <linux/highuid.h>
#include <linux/writeback.h>
#include <linux/hugetlb.h>
#include <linux/security.h>
#include <linux/initrd.h>
#include <linux/times.h>
#include <linux/limits.h>
#include <linux/dcache.h>

#include <asm/uaccess.h>
#include <asm/processor.h>

#ifdef CONFIG_ROOT_NFS
#include <linux/nfs_fs.h>
#endif

#if defined(CONFIG_SYSCTL)

int sercons_escape_char = -1;

/* External variables not in a header file. */
extern int panic_timeout;
extern int C_A_D;
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern int sysctl_panic_on_oom;
extern int max_threads;
extern int sysrq_enabled;
extern int core_uses_pid;
extern int suid_dumpable;
extern char core_pattern[];
extern int cad_pid;
extern int pid_max;
extern int sysctl_lower_zone_protection;
extern int min_free_kbytes;
extern int printk_ratelimit_jiffies;
extern int printk_ratelimit_burst;
extern int percpu_pagelist_fraction;
extern int wake_balance;
extern int sysctl_drop_caches;
extern int write_mapped;
extern int max_writeback_pages;

#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
int unknown_nmi_panic;
extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *,
                                  void __user *, size_t *, loff_t *);
#endif

extern unsigned int vdso_enabled;

#ifdef CONFIG_HIGHMEM
extern int nfs_writeback_lowmem_only;
#endif


int exec_shield = 1;
int exec_shield_randomize = 1;

static int __init setup_exec_shield(char *str)
{
        get_option (&str, &exec_shield);

        return 1;
}

__setup("exec-shield=", setup_exec_shield);

static int __init setup_exec_shield_randomize(char *str)
{
        get_option (&str, &exec_shield_randomize);

        return 1;
}

__setup("exec-shield-randomize=", setup_exec_shield_randomize);

/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
static int maxolduid = 65535;
static int minolduid;
static int min_percpu_pagelist_fract = 8;

static int ngroups_max = NGROUPS_MAX;

#ifdef CONFIG_KMOD
extern char modprobe_path[];
#endif
#ifdef CONFIG_HOTPLUG
extern char hotplug_path[];
#endif
#ifdef CONFIG_CHR_DEV_SG
extern int sg_big_buff;
#endif
#ifdef CONFIG_SYSVIPC
extern size_t shm_ctlmax;
extern size_t shm_ctlall;
extern int shm_ctlmni;
extern int msg_ctlmax;
extern int msg_ctlmnb;
extern int msg_ctlmni;
extern int sem_ctls[];
#endif

#ifdef __sparc__
extern char reboot_command [];
extern int stop_a_enabled;
extern int scons_pwroff;
#endif

#ifdef __hppa__
extern int pwrsw_enabled;
extern int unaligned_enabled;
#endif

#ifdef CONFIG_ARCH_S390
#ifdef CONFIG_MATHEMU
extern int sysctl_ieee_emulation_warnings;
#endif
extern int sysctl_userprocess_debug;
#endif

extern int sysctl_hz_timer;

#ifdef CONFIG_BSD_PROCESS_ACCT
extern int acct_parm[];
#endif

#ifdef CONFIG_IA64
extern int no_unaligned_warning;
#endif

static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
                       ctl_table *, void **);
static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos);

static ctl_table root_table[];
static struct ctl_table_header root_table_header =
        { root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };

static ctl_table kern_table[];
static ctl_table vm_table[];
#ifdef CONFIG_NET
extern ctl_table net_table[];
#endif
static ctl_table proc_table[];
static ctl_table fs_table[];
static ctl_table debug_table[];
static ctl_table dev_table[];
extern ctl_table random_table[];
#ifdef CONFIG_UNIX98_PTYS
extern ctl_table pty_table[];
#endif

#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
int sysctl_legacy_va_layout;
#endif

/* /proc declarations: */

#ifdef CONFIG_PROC_FS

static ssize_t proc_readsys(struct file *, char __user *, size_t, loff_t *);
static ssize_t proc_writesys(struct file *, const char __user *, size_t, loff_t *);
static int proc_opensys(struct inode *, struct file *);

struct file_operations proc_sys_file_operations = {
        .open           = proc_opensys,
        .read           = proc_readsys,
        .write          = proc_writesys,
};

extern struct proc_dir_entry *proc_sys_root;

static void register_proc_table(ctl_table *, struct proc_dir_entry *, void *);
static void unregister_proc_table(ctl_table *, struct proc_dir_entry *);
#endif

/* The default sysctl tables: */

static ctl_table root_table[] = {
        {
                .ctl_name       = CTL_KERN,
                .procname       = "kernel",
                .mode           = 0555,
                .child          = kern_table,
        },
        {
                .ctl_name       = CTL_VM,
                .procname       = "vm",
                .mode           = 0555,
                .child          = vm_table,
        },
#ifdef CONFIG_NET
        {
                .ctl_name       = CTL_NET,
                .procname       = "net",
                .mode           = 0555,
                .child          = net_table,
        },
#endif
        {
                .ctl_name       = CTL_PROC,
                .procname       = "proc",
                .mode           = 0555,
                .child          = proc_table,
        },
        {
                .ctl_name       = CTL_FS,
                .procname       = "fs",
                .mode           = 0555,
                .child          = fs_table,
        },
        {
                .ctl_name       = CTL_DEBUG,
                .procname       = "debug",
                .mode           = 0555,
                .child          = debug_table,
        },
        {
                .ctl_name       = CTL_DEV,
                .procname       = "dev",
                .mode           = 0555,
                .child          = dev_table,
        },
        { .ctl_name = 0 }
};

static ctl_table kern_table[] = {
        {
                .ctl_name       = KERN_OSTYPE,
                .procname       = "ostype",
                .data           = system_utsname.sysname,
                .maxlen         = sizeof(system_utsname.sysname),
                .mode           = 0444,
                .proc_handler   = &proc_doutsstring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_OSRELEASE,
                .procname       = "osrelease",
                .data           = system_utsname.release,
                .maxlen         = sizeof(system_utsname.release),
                .mode           = 0444,
                .proc_handler   = &proc_doutsstring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_VERSION,
                .procname       = "version",
                .data           = system_utsname.version,
                .maxlen         = sizeof(system_utsname.version),
                .mode           = 0444,
                .proc_handler   = &proc_doutsstring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_NODENAME,
                .procname       = "hostname",
                .data           = system_utsname.nodename,
                .maxlen         = sizeof(system_utsname.nodename),
                .mode           = 0644,
                .proc_handler   = &proc_doutsstring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_DOMAINNAME,
                .procname       = "domainname",
                .data           = system_utsname.domainname,
                .maxlen         = sizeof(system_utsname.domainname),
                .mode           = 0644,
                .proc_handler   = &proc_doutsstring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_PANIC,
                .procname       = "panic",
                .data           = &panic_timeout,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PANIC,
                .procname       = "exec-shield",
                .data           = &exec_shield,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PANIC,
                .procname       = "exec-shield-randomize",
                .data           = &exec_shield_randomize,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PANIC,
                .procname       = "print-fatal-signals",
                .data           = &print_fatal_signals,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#if __i386__
        {
                .ctl_name       = KERN_PANIC,
                .procname       = "vdso",
                .data           = &vdso_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_CORE_USES_PID,
                .procname       = "core_uses_pid",
                .data           = &core_uses_pid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_CORE_PATTERN,
                .procname       = "core_pattern",
                .data           = core_pattern,
                .maxlen         = 64,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_TAINTED,
                .procname       = "tainted",
                .data           = &tainted,
                .maxlen         = sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_CAP_BSET,
                .procname       = "cap-bound",
                .data           = &cap_bset,
                .maxlen         = sizeof(kernel_cap_t),
                .mode           = 0600,
                .proc_handler   = &proc_dointvec_bset,
        },
#ifdef CONFIG_BLK_DEV_INITRD
        {
                .ctl_name       = KERN_REALROOTDEV,
                .procname       = "real-root-dev",
                .data           = &real_root_dev,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef __sparc__
        {
                .ctl_name       = KERN_SPARC_REBOOT,
                .procname       = "reboot-cmd",
                .data           = reboot_command,
                .maxlen         = 256,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_SPARC_STOP_A,
                .procname       = "stop-a",
                .data           = &stop_a_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_SPARC_SCONS_PWROFF,
                .procname       = "scons-poweroff",
                .data           = &scons_pwroff,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef __hppa__
        {
                .ctl_name       = KERN_HPPA_PWRSW,
                .procname       = "soft-power",
                .data           = &pwrsw_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_HPPA_UNALIGNED,
                .procname       = "unaligned-trap",
                .data           = &unaligned_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_CTLALTDEL,
                .procname       = "ctrl-alt-del",
                .data           = &C_A_D,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PRINTK,
                .procname       = "printk",
                .data           = &console_loglevel,
                .maxlen         = 4*sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#ifdef CONFIG_KMOD
        {
                .ctl_name       = KERN_MODPROBE,
                .procname       = "modprobe",
                .data           = &modprobe_path,
                .maxlen         = KMOD_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
#endif
#ifdef CONFIG_HOTPLUG
        {
                .ctl_name       = KERN_HOTPLUG,
                .procname       = "hotplug",
                .data           = &hotplug_path,
                .maxlen         = KMOD_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
#endif
#ifdef CONFIG_CHR_DEV_SG
        {
                .ctl_name       = KERN_SG_BIG_BUFF,
                .procname       = "sg-big-buff",
                .data           = &sg_big_buff,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
        {
                .ctl_name       = KERN_ACCT,
                .procname       = "acct",
                .data           = &acct_parm,
                .maxlen         = 3*sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_SYSVIPC
        {
                .ctl_name       = KERN_SHMMAX,
                .procname       = "shmmax",
                .data           = &shm_ctlmax,
                .maxlen         = sizeof (size_t),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
        },
        {
                .ctl_name       = KERN_SHMALL,
                .procname       = "shmall",
                .data           = &shm_ctlall,
                .maxlen         = sizeof (size_t),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
        },
        {
                .ctl_name       = KERN_SHMMNI,
                .procname       = "shmmni",
                .data           = &shm_ctlmni,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_MSGMAX,
                .procname       = "msgmax",
                .data           = &msg_ctlmax,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_MSGMNI,
                .procname       = "msgmni",
                .data           = &msg_ctlmni,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_MSGMNB,
                .procname       =  "msgmnb",
                .data           = &msg_ctlmnb,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_SEM,
                .procname       = "sem",
                .data           = &sem_ctls,
                .maxlen         = 4*sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_MAGIC_SYSRQ
        {
                .ctl_name       = KERN_SYSRQ,
                .procname       = "sysrq",
                .data           = &sysrq_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_CADPID,
                .procname       = "cad_pid",
                .data           = &cad_pid,
                .maxlen         = sizeof (int),
                .mode           = 0600,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_MAX_THREADS,
                .procname       = "threads-max",
                .data           = &max_threads,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_RANDOM,
                .procname       = "random",
                .mode           = 0555,
                .child          = random_table,
        },
#ifdef CONFIG_UNIX98_PTYS
        {
                .ctl_name       = KERN_PTY,
                .procname       = "pty",
                .mode           = 0555,
                .child          = pty_table,
        },
#endif
        {
                .ctl_name       = KERN_OVERFLOWUID,
                .procname       = "overflowuid",
                .data           = &overflowuid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .ctl_name       = KERN_OVERFLOWGID,
                .procname       = "overflowgid",
                .data           = &overflowgid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
#ifdef CONFIG_ARCH_S390
#ifdef CONFIG_MATHEMU
        {
                .ctl_name       = KERN_IEEE_EMULATION_WARNINGS,
                .procname       = "ieee_emulation_warnings",
                .data           = &sysctl_ieee_emulation_warnings,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_NO_IDLE_HZ
        {
                .ctl_name       = KERN_HZ_TIMER,
                .procname       = "hz_timer",
                .data           = &sysctl_hz_timer,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_S390_USER_DEBUG_LOGGING,
                .procname       = "userprocess_debug",
                .data           = &sysctl_userprocess_debug,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_SERIAL_CORE_CONSOLE
        {
                .ctl_name       = KERN_SERCONS_ESC,
                .procname       = "sercons_esc",
                .data           = &sercons_escape_char,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_PIDMAX,
                .procname       = "pid_max",
                .data           = &pid_max,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PANIC_ON_OOPS,
                .procname       = "panic_on_oops",
                .data           = &panic_on_oops,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PRINTK_RATELIMIT,
                .procname       = "printk_ratelimit",
                .data           = &printk_ratelimit_jiffies,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_jiffies,
                .strategy       = &sysctl_jiffies,
        },
        {
                .ctl_name       = KERN_PRINTK_RATELIMIT_BURST,
                .procname       = "printk_ratelimit_burst",
                .data           = &printk_ratelimit_burst,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_NGROUPS_MAX,
                .procname       = "ngroups_max",
                .data           = &ngroups_max,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
        {
                .ctl_name       = KERN_UNKNOWN_NMI_PANIC,
                .procname       = "unknown_nmi_panic",
                .data           = &unknown_nmi_panic,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_unknown_nmi_panic,
        },
#endif
        {
                .ctl_name       = KERN_SETUID_DUMPABLE,
                .procname       = "suid_dumpable",
                .data           = &suid_dumpable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_WAKE_BALANCE,
                .procname       = "wake_balance",
                .data           = &wake_balance,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PANIC_ON_NMI,
                .procname       = "panic_on_unrecovered_nmi",
                .data           = &panic_on_unrecovered_nmi,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#ifdef CONFIG_IA64
        {
                .ctl_name       = KERN_IA64_UNALIGNED,
                .procname       = "ignore-unaligned-usertrap",
                .data           = &no_unaligned_warning,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        { .ctl_name = 0 }
};

/* Constants for minimum and maximum testing in vm_table.
   We use these as one-element integer vectors. */
static int zero;
static int one_hundred = 100;


static ctl_table vm_table[] = {
        {
                .ctl_name       = VM_OVERCOMMIT_MEMORY,
                .procname       = "overcommit_memory",
                .data           = &sysctl_overcommit_memory,
                .maxlen         = sizeof(sysctl_overcommit_memory),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_PANIC_ON_OOM,
                .procname       = "panic_on_oom",
                .data           = &sysctl_panic_on_oom,
                .maxlen         = sizeof(sysctl_panic_on_oom),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_OVERCOMMIT_RATIO,
                .procname       = "overcommit_ratio",
                .data           = &sysctl_overcommit_ratio,
                .maxlen         = sizeof(sysctl_overcommit_ratio),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_PAGE_CLUSTER,
                .procname       = "page-cluster", 
                .data           = &page_cluster,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_DIRTY_BACKGROUND,
                .procname       = "dirty_background_ratio",
                .data           = &dirty_background_ratio,
                .maxlen         = sizeof(dirty_background_ratio),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .ctl_name       = VM_DIRTY_RATIO,
                .procname       = "dirty_ratio",
                .data           = &vm_dirty_ratio,
                .maxlen         = sizeof(vm_dirty_ratio),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .ctl_name       = VM_DIRTY_WB_CS,
                .procname       = "dirty_writeback_centisecs",
                .data           = &dirty_writeback_centisecs,
                .maxlen         = sizeof(dirty_writeback_centisecs),
                .mode           = 0644,
                .proc_handler   = &dirty_writeback_centisecs_handler,
        },
        {
                .ctl_name       = VM_DIRTY_EXPIRE_CS,
                .procname       = "dirty_expire_centisecs",
                .data           = &dirty_expire_centisecs,
                .maxlen         = sizeof(dirty_expire_centisecs),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_NR_PDFLUSH_THREADS,
                .procname       = "nr_pdflush_threads",
                .data           = &nr_pdflush_threads,
                .maxlen         = sizeof nr_pdflush_threads,
                .mode           = 0444 /* read-only*/,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_SWAPPINESS,
                .procname       = "swappiness",
                .data           = &vm_swappiness,
                .maxlen         = sizeof(vm_swappiness),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
#ifdef CONFIG_HUGETLB_PAGE
         {
                .ctl_name       = VM_HUGETLB_PAGES,
                .procname       = "nr_hugepages",
                .data           = &max_huge_pages,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &hugetlb_sysctl_handler,
                .extra1         = (void *)&hugetlb_zero,
                .extra2         = (void *)&hugetlb_infinity,
         },
         {
                .ctl_name       = VM_HUGETLB_GROUP,
                .procname       = "hugetlb_shm_group",
                .data           = &sysctl_hugetlb_shm_group,
                .maxlen         = sizeof(gid_t),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
         },
#endif
        {
                .ctl_name       = VM_LOWER_ZONE_PROTECTION,
                .procname       = "lower_zone_protection",
                .data           = &sysctl_lower_zone_protection,
                .maxlen         = sizeof(sysctl_lower_zone_protection),
                .mode           = 0644,
                .proc_handler   = &lower_zone_protection_sysctl_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_MIN_FREE_KBYTES,
                .procname       = "min_free_kbytes",
                .data           = &min_free_kbytes,
                .maxlen         = sizeof(min_free_kbytes),
                .mode           = 0644,
                .proc_handler   = &min_free_kbytes_sysctl_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_MAX_MAP_COUNT,
                .procname       = "max_map_count",
                .data           = &sysctl_max_map_count,
                .maxlen         = sizeof(sysctl_max_map_count),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec
        },
        {
                .ctl_name       = VM_LAPTOP_MODE,
                .procname       = "laptop_mode",
                .data           = &laptop_mode,
                .maxlen         = sizeof(laptop_mode),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_BLOCK_DUMP,
                .procname       = "block_dump",
                .data           = &block_dump,
                .maxlen         = sizeof(block_dump),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_VFS_CACHE_PRESSURE,
                .procname       = "vfs_cache_pressure",
                .data           = &sysctl_vfs_cache_pressure,
                .maxlen         = sizeof(sysctl_vfs_cache_pressure),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
        {
                .ctl_name       = VM_LEGACY_VA_LAYOUT,
                .procname       = "legacy_va_layout",
                .data           = &sysctl_legacy_va_layout,
                .maxlen         = sizeof(sysctl_legacy_va_layout),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
#endif
        {
                .ctl_name       = VM_OOM_KILL,
                .procname       = "oom-kill",
                .data           = &oom_kill_enabled,
                .maxlen         = sizeof(oom_kill_enabled),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_MAX_QUEUE_DEPTH,
                .procname       = "max_queue_depth",
                .data           = &vm_max_queue_depth,
                .maxlen         = sizeof(vm_max_queue_depth),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_PERCPU_PAGELIST_FRACTION,
                .procname       = "percpu_pagelist_fraction",
                .data           = &percpu_pagelist_fraction,
                .maxlen         = sizeof(percpu_pagelist_fraction),
                .mode           = 0644,
                .proc_handler   = &percpu_pagelist_fraction_sysctl_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_percpu_pagelist_fract,
        },
        {
                .ctl_name       = VM_PAGECACHE,
                .procname       = "pagecache",
                .data           = &pagecache_maxpercent,
                .maxlen         = sizeof(pagecache_maxpercent),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .ctl_name       = VM_INACTIVE_PERCENT,
                .procname       = "inactive_percent",
                .data           = &vm_inactive_percent,
                .maxlen         = sizeof(vm_inactive_percent),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .ctl_name       = VM_DROP_PAGECACHE,
                .procname       = "drop_caches",
                .data           = &sysctl_drop_caches,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = drop_caches_sysctl_handler,
                .strategy       = &sysctl_intvec,
        },
        {
                .ctl_name       = VM_WRITE_MAPPED,
                .procname       = "write-mapped",
                .data           = &write_mapped,
                .maxlen         = sizeof(write_mapped),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,

        },
#ifdef CONFIG_HIGHMEM
        {
                .ctl_name       = VM_NFS_WB_LOWMEM,
                .procname       = "nfs-writeback-lowmem-only",
                .data           = &nfs_writeback_lowmem_only,
                .maxlen         = sizeof(&nfs_writeback_lowmem_only),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
#endif
#ifdef CONFIG_SWAP
        {
                .ctl_name       = VM_SWAP_TOKEN_TIMEOUT,
                .procname       = "swap_token_timeout",
                .data           = &swap_token_default_timeout,
                .maxlen         = sizeof(swap_token_default_timeout),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_jiffies,
                .strategy       = &sysctl_jiffies,
        },
#endif
{
                .ctl_name       = VM_MAX_WRITEBACK_PAGES,
                .procname       = "max_writeback_pages",
                .data           = &max_writeback_pages,
                .maxlen         = sizeof(max_writeback_pages),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
},
        { .ctl_name = 0 }
};

static ctl_table proc_table[] = {
        { .ctl_name = 0 }
};

static ctl_table fs_table[] = {
        {
                .ctl_name       = FS_NRINODE,
                .procname       = "inode-nr",
                .data           = &inodes_stat,
                .maxlen         = 2*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_STATINODE,
                .procname       = "inode-state",
                .data           = &inodes_stat,
                .maxlen         = 7*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_NRFILE,
                .procname       = "file-nr",
                .data           = &files_stat,
                .maxlen         = 3*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_MAXFILE,
                .procname       = "file-max",
                .data           = &files_stat.max_files,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_DENTRY,
                .procname       = "dentry-state",
                .data           = &dentry_stat,
                .maxlen         = 6*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_OVERFLOWUID,
                .procname       = "overflowuid",
                .data           = &fs_overflowuid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .ctl_name       = FS_OVERFLOWGID,
                .procname       = "overflowgid",
                .data           = &fs_overflowgid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .ctl_name       = FS_LEASES,
                .procname       = "leases-enable",
                .data           = &leases_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_DIR_NOTIFY,
                .procname       = "dir-notify-enable",
                .data           = &dir_notify_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_LEASE_TIME,
                .procname       = "lease-break-time",
                .data           = &lease_break_time,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_AIO_NR,
                .procname       = "aio-nr",
                .data           = &aio_nr,
                .maxlen         = sizeof(aio_nr),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_AIO_MAX_NR,
                .procname       = "aio-max-nr",
                .data           = &aio_max_nr,
                .maxlen         = sizeof(aio_max_nr),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        { .ctl_name = 0 }
};

static ctl_table debug_table[] = {
        { .ctl_name = 0 }
};

static ctl_table dev_table[] = {
        { .ctl_name = 0 }
};  

extern void init_irq_proc (void);

static spinlock_t sysctl_lock = SPIN_LOCK_UNLOCKED;

/* called under sysctl_lock */
static int use_table(struct ctl_table_header *p)
{
        if (unlikely(p->unregistering))
                return 0;
        p->used++;
        return 1;
}

/* called under sysctl_lock */
static void unuse_table(struct ctl_table_header *p)
{
        if (!--p->used)
                if (unlikely(p->unregistering))
                        complete(p->unregistering);
}

/* called under sysctl_lock, will reacquire if has to wait */
static void start_unregistering(struct ctl_table_header *p)
{
        struct completion wait;

        init_completion(&wait);
        p->unregistering = &wait;
        /*
         * if p->used is 0, nobody will ever dereference ->unregistering,
         * so leaving it dangling is OK; we just need non-NULL.
         */
        if (unlikely(p->used)) {
                spin_unlock(&sysctl_lock);
                wait_for_completion(&wait);
                spin_lock(&sysctl_lock);
        }
        /*
         * do not remove from the list until nobody holds it; walking the
         * list in do_sysctl() relies on that.
         */
        list_del_init(&p->ctl_entry);
}

void __init sysctl_init(void)
{
#ifdef CONFIG_PROC_FS
        register_proc_table(root_table, proc_sys_root, &root_table_header);
        init_irq_proc();
#endif
}

int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
               void __user *newval, size_t newlen)
{
        struct list_head *tmp;
        int error = -ENOTDIR;

        if (nlen <= 0 || nlen >= CTL_MAXNAME)
                return -ENOTDIR;
        if (oldval) {
                int old_len;
                if (!oldlenp || get_user(old_len, oldlenp))
                        return -EFAULT;
        }
        spin_lock(&sysctl_lock);
        tmp = &root_table_header.ctl_entry;
        do {
                struct ctl_table_header *head =
                        list_entry(tmp, struct ctl_table_header, ctl_entry);
                void *context = NULL;

                if (!use_table(head))
                        continue;

                spin_unlock(&sysctl_lock);

                error = parse_table(name, nlen, oldval, oldlenp, 
                                        newval, newlen, head->ctl_table,
                                        &context);
                if (context)
                        kfree(context);

                spin_lock(&sysctl_lock);
                unuse_table(head);
                if (error != -ENOTDIR)
                        break;
        } while ((tmp = tmp->next) != &root_table_header.ctl_entry);
        spin_unlock(&sysctl_lock);
        return error;
}

asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
{
        struct __sysctl_args tmp;
        int error;

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

        lock_kernel();
        error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
                          tmp.newval, tmp.newlen);
        unlock_kernel();
        return error;
}

/*
 * ctl_perm does NOT grant the superuser all rights automatically, because
 * some sysctl variables are readonly even to root.
 */

static int test_perm(int mode, int op)
{
        if (!current->euid)
                mode >>= 6;
        else if (in_egroup_p(0))
                mode >>= 3;
        if ((mode & op & 0007) == op)
                return 0;
        return -EACCES;
}

static inline int ctl_perm(ctl_table *table, int op)
{
        int error;
        error = security_sysctl(table, op);
        if (error)
                return error;
        return test_perm(table->mode, op);
}

static int parse_table(int __user *name, int nlen,
                       void __user *oldval, size_t __user *oldlenp,
                       void __user *newval, size_t newlen,
                       ctl_table *table, void **context)
{
        int n;
repeat:
        if (!nlen)
                return -ENOTDIR;
        if (get_user(n, name))
                return -EFAULT;
        for ( ; table->ctl_name; table++) {
                if (n == table->ctl_name || table->ctl_name == CTL_ANY) {
                        int error;
                        if (table->child) {
                                if (ctl_perm(table, 001))
                                        return -EPERM;
                                if (table->strategy) {
                                        error = table->strategy(
                                                table, name, nlen,
                                                oldval, oldlenp,
                                                newval, newlen, context);
                                        if (error)
                                                return error;
                                }
                                name++;
                                nlen--;
                                table = table->child;
                                goto repeat;
                        }
                        error = do_sysctl_strategy(table, name, nlen,
                                                   oldval, oldlenp,
                                                   newval, newlen, context);
                        return error;
                }
        }
        return -ENOTDIR;
}

/* Perform the actual read/write of a sysctl table entry. */
int do_sysctl_strategy (ctl_table *table, 
                        int __user *name, int nlen,
                        void __user *oldval, size_t __user *oldlenp,
                        void __user *newval, size_t newlen, void **context)
{
        int op = 0, rc;
        size_t len;

        if (oldval)
                op |= 004;
        if (newval) 
                op |= 002;
        if (ctl_perm(table, op))
                return -EPERM;

        if (table->strategy) {
                rc = table->strategy(table, name, nlen, oldval, oldlenp,
                                     newval, newlen, context);
                if (rc < 0)
                        return rc;
                if (rc > 0)
                        return 0;
        }

        /* If there is no strategy routine, or if the strategy returns
         * zero, proceed with automatic r/w */
        if (table->data && table->maxlen) {
                if (oldval && oldlenp) {
                        if (get_user(len, oldlenp))
                                return -EFAULT;
                        if (len) {
                                if (len > table->maxlen)
                                        len = table->maxlen;
                                if(copy_to_user(oldval, table->data, len))
                                        return -EFAULT;
                                if(put_user(len, oldlenp))
                                        return -EFAULT;
                        }
                }
                if (newval && newlen) {
                        len = newlen;
                        if (len > table->maxlen)
                                len = table->maxlen;
                        if(copy_from_user(table->data, newval, len))
                                return -EFAULT;
                }
        }
        return 0;
}

/**
 * register_sysctl_table - register a sysctl hierarchy
 * @table: the top-level table structure
 * @insert_at_head: whether the entry should be inserted in front or at the end
 *
 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
 * array. An entry with a ctl_name of 0 terminates the table. 
 *
 * The members of the &ctl_table structure are used as follows:
 *
 * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
 *            must be unique within that level of sysctl
 *
 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
 *            enter a sysctl file
 *
 * data - a pointer to data for use by proc_handler
 *
 * maxlen - the maximum size in bytes of the data
 *
 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
 *
 * child - a pointer to the child sysctl table if this entry is a directory, or
 *         %NULL.
 *
 * proc_handler - the text handler routine (described below)
 *
 * strategy - the strategy routine (described below)
 *
 * de - for internal use by the sysctl routines
 *
 * extra1, extra2 - extra pointers usable by the proc handler routines
 *
 * Leaf nodes in the sysctl tree will be represented by a single file
 * under /proc; non-leaf nodes will be represented by directories.
 *
 * sysctl(2) can automatically manage read and write requests through
 * the sysctl table.  The data and maxlen fields of the ctl_table
 * struct enable minimal validation of the values being written to be
 * performed, and the mode field allows minimal authentication.
 *
 * More sophisticated management can be enabled by the provision of a
 * strategy routine with the table entry.  This will be called before
 * any automatic read or write of the data is performed.
 *
 * The strategy routine may return
 *
 * < 0 - Error occurred (error is passed to user process)
 *
 * 0   - OK - proceed with automatic read or write.
 *
 * > 0 - OK - read or write has been done by the strategy routine, so
 *       return immediately.
 *
 * There must be a proc_handler routine for any terminal nodes
 * mirrored under /proc/sys (non-terminals are handled by a built-in
 * directory handler).  Several default handlers are available to
 * cover common cases -
 *
 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 
 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
 *
 * It is the handler's job to read the input buffer from user memory
 * and process it. The handler should return 0 on success.
 *
 * This routine returns %NULL on a failure to register, and a pointer
 * to the table header on success.
 */
struct ctl_table_header *register_sysctl_table(ctl_table * table, 
                                               int insert_at_head)
{
        struct ctl_table_header *tmp;
        tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
        if (!tmp)
                return NULL;
        tmp->ctl_table = table;
        INIT_LIST_HEAD(&tmp->ctl_entry);
        tmp->used = 0;
        tmp->unregistering = NULL;
        spin_lock(&sysctl_lock);
        if (insert_at_head)
                list_add(&tmp->ctl_entry, &root_table_header.ctl_entry);
        else
                list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
        spin_unlock(&sysctl_lock);
#ifdef CONFIG_PROC_FS
        register_proc_table(table, proc_sys_root, tmp);
#endif
        return tmp;
}

/**
 * unregister_sysctl_table - unregister a sysctl table hierarchy
 * @header: the header returned from register_sysctl_table
 *
 * Unregisters the sysctl table and all children. proc entries may not
 * actually be removed until they are no longer used by anyone.
 */
void unregister_sysctl_table(struct ctl_table_header * header)
{
        might_sleep();
        spin_lock(&sysctl_lock);
        start_unregistering(header);
#ifdef CONFIG_PROC_FS
        unregister_proc_table(header->ctl_table, proc_sys_root);
#endif
        spin_unlock(&sysctl_lock);
        kfree(header);
}

/*
 * /proc/sys support
 */

#ifdef CONFIG_PROC_FS

/* Scan the sysctl entries in table and add them all into /proc */
static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
{
        struct proc_dir_entry *de;
        int len;
        mode_t mode;
        
        for (; table->ctl_name; table++) {
                /* Can't do anything without a proc name. */
                if (!table->procname)
                        continue;
                /* Maybe we can't do anything with it... */
                if (!table->proc_handler && !table->child) {
                        printk(KERN_WARNING "SYSCTL: Can't register %s\n",
                                table->procname);
                        continue;
                }

                len = strlen(table->procname);
                mode = table->mode;

                de = NULL;
                if (table->proc_handler)
                        mode |= S_IFREG;
                else {
                        mode |= S_IFDIR;
                        for (de = root->subdir; de; de = de->next) {
                                if (proc_match(len, table->procname, de))
                                        break;
                        }
                        /* If the subdir exists already, de is non-NULL */
                }

                if (!de) {
                        de = create_proc_entry(table->procname, mode, root);
                        if (!de)
                                continue;
                        de->set = set;
                        de->data = (void *) table;
                        if (table->proc_handler)
                                de->proc_fops = &proc_sys_file_operations;
                }
                table->de = de;
                if (de->mode & S_IFDIR)
                        register_proc_table(table->child, de, set);
        }
}

/*
 * Unregister a /proc sysctl table and any subdirectories.
 */
static void unregister_proc_table(ctl_table * table, struct proc_dir_entry *root)
{
        struct proc_dir_entry *de;
        for (; table->ctl_name; table++) {
                if (!(de = table->de))
                        continue;
                if (de->mode & S_IFDIR) {
                        if (!table->child) {
                                printk (KERN_ALERT "Help - malformed sysctl tree on free\n");
                                continue;
                        }
                        unregister_proc_table(table->child, de);

                        /* Don't unregister directories which still have entries.. */
                        if (de->subdir)
                                continue;
                }

                /*
                 * In any case, mark the entry as goner; we'll keep it
                 * around if it's busy, but we'll know to do nothing with
                 * its fields.  We are under sysctl_lock here.
                 */
                de->data = NULL;

                /* Don't unregister proc entries that are still being used.. */
                if (atomic_read(&de->count))
                        continue;

                table->de = NULL;
                remove_proc_entry(table->procname, root);
        }
}

static ssize_t do_rw_proc(int write, struct file * file, char __user * buf,
                          size_t count, loff_t *ppos)
{
        int op;
        struct proc_dir_entry *de = PDE(file->f_dentry->d_inode);
        struct ctl_table *table;
        size_t res;
        ssize_t error = -ENOTDIR;
        
        spin_lock(&sysctl_lock);
        if (de && de->data && use_table(de->set)) {
                /*
                 * at that point we know that sysctl was not unregistered
                 * and won't be until we finish
                 */
                spin_unlock(&sysctl_lock);
                table = (struct ctl_table *) de->data;
                if (!table || !table->proc_handler)
                        goto out;
                error = -EPERM;
                op = (write ? 002 : 004);
                if (ctl_perm(table, op))
                        goto out;
                
                /* careful: calling conventions are nasty here */
                res = count;
                error = (*table->proc_handler)(table, write, file,
                                                buf, &res, ppos);
                if (!error)
                        error = res;
        out:
                spin_lock(&sysctl_lock);
                unuse_table(de->set);
        }
        spin_unlock(&sysctl_lock);
        return error;
}

static int proc_opensys(struct inode *inode, struct file *file)
{
        if (file->f_mode & FMODE_WRITE) {
                /*
                 * sysctl entries that are not writable,
                 * are _NOT_ writable, capabilities or not.
                 */
                if (!(inode->i_mode & S_IWUSR))
                        return -EPERM;
        }

        return 0;
}

static ssize_t proc_readsys(struct file * file, char __user * buf,
                            size_t count, loff_t *ppos)
{
        return do_rw_proc(0, file, buf, count, ppos);
}

static ssize_t proc_writesys(struct file * file, const char __user * buf,
                             size_t count, loff_t *ppos)
{
        return do_rw_proc(1, file, (char __user *) buf, count, ppos);
}

/**
 * proc_dostring - read a string sysctl
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes a string from/to the user buffer. If the kernel
 * buffer provided is not large enough to hold the string, the
 * string is truncated. The copied string is %NULL-terminated.
 * If the string is being read by the user process, it is copied
 * and a newline '\n' is added. It is truncated if the buffer is
 * not large enough.
 *
 * Returns 0 on success.
 */
int proc_dostring(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        size_t len;
        char __user *p;
        char c;
        
        if (!table->data || !table->maxlen || !*lenp ||
            (*ppos && !write)) {
                *lenp = 0;
                return 0;
        }
        
        if (write) {
                len = 0;
                p = buffer;
                while (len < *lenp) {
                        if (get_user(c, p++))
                                return -EFAULT;
                        if (c == 0 || c == '\n')
                                break;
                        len++;
                }
                if (len >= table->maxlen)
                        len = table->maxlen-1;
                if(copy_from_user(table->data, buffer, len))
                        return -EFAULT;
                ((char *) table->data)[len] = 0;
                *ppos += *lenp;
        } else {
                len = strlen(table->data);
                if (len > table->maxlen)
                        len = table->maxlen;
                if (len > *lenp)
                        len = *lenp;
                if (len)
                        if(copy_to_user(buffer, table->data, len))
                                return -EFAULT;
                if (len < *lenp) {
                        if(put_user('\n', ((char __user *) buffer) + len))
                                return -EFAULT;
                        len++;
                }
                *lenp = len;
                *ppos += len;
        }
        return 0;
}

/*
 *      Special case of dostring for the UTS structure. This has locks
 *      to observe. Should this be in kernel/sys.c ????
 */
 
static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        int r;

        if (!write) {
                down_read(&uts_sem);
                r=proc_dostring(table,0,filp,buffer,lenp, ppos);
                up_read(&uts_sem);
        } else {
                down_write(&uts_sem);
                r=proc_dostring(table,1,filp,buffer,lenp, ppos);
                up_write(&uts_sem);
        }
        return r;
}

static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
                                 int *valp,
                                 int write, void *data)
{
        if (write) {
                *valp = *negp ? -*lvalp : *lvalp;
        } else {
                int val = *valp;
                if (val < 0) {
                        *negp = -1;
                        *lvalp = (unsigned long)-val;
                } else {
                        *negp = 0;
                        *lvalp = (unsigned long)val;
                }
        }
        return 0;
}

static int do_proc_dointvec(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos,
                  int (*conv)(int *negp, unsigned long *lvalp, int *valp,
                              int write, void *data),
                  void *data)
{
#define TMPBUFLEN 21
        int *i, vleft, first=1, neg, val;
        unsigned long lval;
        size_t left, len;
        
        char buf[TMPBUFLEN], *p;
        char __user *s = buffer;
        
        if (!table->data || !table->maxlen || !*lenp ||
            (*ppos && !write)) {
                *lenp = 0;
                return 0;
        }
        
        i = (int *) table->data;
        vleft = table->maxlen / sizeof(*i);
        left = *lenp;

        if (!conv)
                conv = do_proc_dointvec_conv;

        for (; left && vleft--; i++, first=0) {
                if (write) {
                        while (left) {
                                char c;
                                if (get_user(c, s))
                                        return -EFAULT;
                                if (!isspace(c))
                                        break;
                                left--;
                                s++;
                        }
                        if (!left)
                                break;
                        neg = 0;
                        len = left;
                        if (len > sizeof(buf) - 1)
                                len = sizeof(buf) - 1;
                        if (copy_from_user(buf, s, len))
                                return -EFAULT;
                        buf[len] = 0;
                        p = buf;
                        if (*p == '-' && left > 1) {
                                neg = 1;
                                left--, p++;
                        }
                        if (*p < '0' || *p > '9')
                                break;

                        lval = simple_strtoul(p, &p, 0);

                        len = p-buf;
                        if ((len < left) && *p && !isspace(*p))
                                break;
                        if (neg)
                                val = -val;
                        s += len;
                        left -= len;

                        if (conv(&neg, &lval, i, 1, data))
                                break;
                } else {
                        p = buf;
                        if (!first)
                                *p++ = '\t';
        
                        if (conv(&neg, &lval, i, 0, data))
                                break;

                        sprintf(p, "%s%lu", neg ? "-" : "", lval);
                        len = strlen(buf);
                        if (len > left)
                                len = left;
                        if(copy_to_user(s, buf, len))
                                return -EFAULT;
                        left -= len;
                        s += len;
                }
        }

        if (!write && !first && left) {
                if(put_user('\n', s))
                        return -EFAULT;
                left--, s++;
        }
        if (write) {
                while (left) {
                        char c;
                        if (get_user(c, s++))
                                return -EFAULT;
                        if (!isspace(c))
                                break;
                        left--;
                }
        }
        if (write && first)
                return -EINVAL;
        *lenp -= left;
        *ppos += *lenp;
        return 0;
#undef TMPBUFLEN
}

/**
 * proc_dointvec - read a vector of integers
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
 * values from/to the user buffer, treated as an ASCII string. 
 *
 * Returns 0 on success.
 */
int proc_dointvec(ctl_table *table, int write, struct file *filp,
                     void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                            NULL,NULL);
}

#define OP_SET  0
#define OP_AND  1
#define OP_OR   2
#define OP_MAX  3
#define OP_MIN  4

static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp,
                                      int *valp,
                                      int write, void *data)
{
        int op = *(int *)data;
        if (write) {
                int val = *negp ? -*lvalp : *lvalp;
                switch(op) {
                case OP_SET:    *valp = val; break;
                case OP_AND:    *valp &= val; break;
                case OP_OR:     *valp |= val; break;
                case OP_MAX:    if(*valp < val)
                                        *valp = val;
                                break;
                case OP_MIN:    if(*valp > val)
                                *valp = val;
                                break;
                }
        } else {
                int val = *valp;
                if (val < 0) {
                        *negp = -1;
                        *lvalp = (unsigned long)-val;
                } else {
                        *negp = 0;
                        *lvalp = (unsigned long)val;
                }
        }
        return 0;
}

/*
 *      init may raise the set.
 */
 
int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
                        void __user *buffer, size_t *lenp, loff_t *ppos)
{
        int op;

        if (!capable(CAP_SYS_MODULE)) {
                return -EPERM;
        }

        op = (current->pid == 1) ? OP_SET : OP_AND;
        return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                                do_proc_dointvec_bset_conv,&op);
}

struct do_proc_dointvec_minmax_conv_param {
        int *min;
        int *max;
};

static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp, 
                                        int *valp, 
                                        int write, void *data)
{
        struct do_proc_dointvec_minmax_conv_param *param = data;
        if (write) {
                int val = *negp ? -*lvalp : *lvalp;
                if ((param->min && *param->min > val) ||
                    (param->max && *param->max < val))
                        return -EINVAL;
                *valp = val;
        } else {
                int val = *valp;
                if (val < 0) {
                        *negp = -1;
                        *lvalp = (unsigned long)-val;
                } else {
                        *negp = 0;
                        *lvalp = (unsigned long)val;
                }
        }
        return 0;
}

/**
 * proc_dointvec_minmax - read a vector of integers with min/max values
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
 * values from/to the user buffer, treated as an ASCII string.
 *
 * This routine will ensure the values are within the range specified by
 * table->extra1 (min) and table->extra2 (max).
 *
 * Returns 0 on success.
 */
int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        struct do_proc_dointvec_minmax_conv_param param = {
                .min = (int *) table->extra1,
                .max = (int *) table->extra2,
        };
        return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
                                do_proc_dointvec_minmax_conv, &param);
}

static int do_proc_doulongvec_minmax(ctl_table *table, int write,
                                     struct file *filp,
                                     void __user *buffer,
                                     size_t *lenp, loff_t *ppos,
                                     unsigned long convmul,
                                     unsigned long convdiv)
{
#define TMPBUFLEN 21
        unsigned long *i, *min, *max, val;
        int vleft, first=1, neg;

        size_t len, left;
        char buf[TMPBUFLEN], *p;
        char __user *s = buffer;
        
        if (!table->data || !table->maxlen || !*lenp ||
            (*ppos && !write)) {
                *lenp = 0;
                return 0;
        }
        
        i = (unsigned long *) table->data;
        min = (unsigned long *) table->extra1;
        max = (unsigned long *) table->extra2;
        vleft = table->maxlen / sizeof(unsigned long);
        left = *lenp;
        
        for (; left && vleft--; i++, min++, max++, first=0) {
                if (write) {
                        while (left) {
                                char c;
                                if (get_user(c, s))
                                        return -EFAULT;
                                if (!isspace(c))
                                        break;
                                left--;
                                s++;
                        }
                        if (!left)
                                break;
                        neg = 0;
                        len = left;
                        if (len > TMPBUFLEN-1)
                                len = TMPBUFLEN-1;
                        if (copy_from_user(buf, s, len))
                                return -EFAULT;
                        buf[len] = 0;
                        p = buf;
                        if (*p == '-' && left > 1) {
                                neg = 1;
                                left--, p++;
                        }
                        if (*p < '0' || *p > '9')
                                break;
                        val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
                        len = p-buf;
                        if ((len < left) && *p && !isspace(*p))
                                break;
                        if (neg)
                                val = -val;
                        s += len;
                        left -= len;

                        if(neg)
                                continue;
                        if ((min && val < *min) || (max && val > *max))
                                continue;
                        *i = val;
                } else {
                        p = buf;
                        if (!first)
                                *p++ = '\t';
                        sprintf(p, "%lu", convdiv * (*i) / convmul);
                        len = strlen(buf);
                        if (len > left)
                                len = left;
                        if(copy_to_user(s, buf, len))
                                return -EFAULT;
                        left -= len;
                        s += len;
                }
        }

        if (!write && !first && left) {
                if(put_user('\n', s))
                        return -EFAULT;
                left--, s++;
        }
        if (write) {
                while (left) {
                        char c;
                        if (get_user(c, s++))
                                return -EFAULT;
                        if (!isspace(c))
                                break;
                        left--;
                }
        }
        if (write && first)
                return -EINVAL;
        *lenp -= left;
        *ppos += *lenp;
        return 0;
#undef TMPBUFLEN
}

/**
 * proc_doulongvec_minmax - read a vector of long integers with min/max values
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
 * values from/to the user buffer, treated as an ASCII string.
 *
 * This routine will ensure the values are within the range specified by
 * table->extra1 (min) and table->extra2 (max).
 *
 * Returns 0 on success.
 */
int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
                           void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos, 1l, 1l);
}

/**
 * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
 * values from/to the user buffer, treated as an ASCII string. The values
 * are treated as milliseconds, and converted to jiffies when they are stored.
 *
 * This routine will ensure the values are within the range specified by
 * table->extra1 (min) and table->extra2 (max).
 *
 * Returns 0 on success.
 */
int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
                                      struct file *filp,
                                      void __user *buffer,
                                      size_t *lenp, loff_t *ppos)
{
    return do_proc_doulongvec_minmax(table, write, filp, buffer,
                                     lenp, ppos, HZ, 1000l);
}


static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
                                         int *valp,
                                         int write, void *data)
{
        if (write) {
                *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
        } else {
                int val = *valp;
                unsigned long lval;
                if (val < 0) {
                        *negp = -1;
                        lval = (unsigned long)-val;
                } else {
                        *negp = 0;
                        lval = (unsigned long)val;
                }
                *lvalp = lval / HZ;
        }
        return 0;
}

static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
                                                int *valp,
                                                int write, void *data)
{
        if (write) {
                *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
        } else {
                int val = *valp;
                unsigned long lval;
                if (val < 0) {
                        *negp = -1;
                        lval = (unsigned long)-val;
                } else {
                        *negp = 0;
                        lval = (unsigned long)val;
                }
                *lvalp = jiffies_to_clock_t(lval);
        }
        return 0;
}

/**
 * proc_dointvec_jiffies - read a vector of integers as seconds
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
 * values from/to the user buffer, treated as an ASCII string. 
 * The values read are assumed to be in seconds, and are converted into
 * jiffies.
 *
 * Returns 0 on success.
 */
int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
                          void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                            do_proc_dointvec_jiffies_conv,NULL);
}

/**
 * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 *
 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
 * values from/to the user buffer, treated as an ASCII string. 
 * The values read are assumed to be in 1/USER_HZ seconds, and 
 * are converted into jiffies.
 *
 * Returns 0 on success.
 */
int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
                                 void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                            do_proc_dointvec_userhz_jiffies_conv,NULL);
}

#else /* CONFIG_PROC_FS */

int proc_dostring(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
                            void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
                        void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
                    void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
                    void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
                    void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
                    void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
                                      struct file *filp,
                                      void __user *buffer,
                                      size_t *lenp, loff_t *ppos)
{
    return -ENOSYS;
}


#endif /* CONFIG_PROC_FS */


/*
 * General sysctl support routines 
 */

/* The generic string strategy routine: */
int sysctl_string(ctl_table *table, int __user *name, int nlen,
                  void __user *oldval, size_t __user *oldlenp,
                  void __user *newval, size_t newlen, void **context)
{
        size_t l, len;
        
        if (!table->data || !table->maxlen) 
                return -ENOTDIR;
        
        if (oldval && oldlenp) {
                if (get_user(len, oldlenp))
                        return -EFAULT;
                if (len) {
                        l = strlen(table->data);
                        if (len > l) len = l;
                        if (len >= table->maxlen)
                                len = table->maxlen;
                        if(copy_to_user(oldval, table->data, len))
                                return -EFAULT;
                        if(put_user(0, ((char __user *) oldval) + len))
                                return -EFAULT;
                        if(put_user(len, oldlenp))
                                return -EFAULT;
                }
        }
        if (newval && newlen) {
                len = newlen;
                if (len > table->maxlen)
                        len = table->maxlen;
                if(copy_from_user(table->data, newval, len))
                        return -EFAULT;
                if (len == table->maxlen)
                        len--;
                ((char *) table->data)[len] = 0;
        }
        return 0;
}

/*
 * This function makes sure that all of the integers in the vector
 * are between the minimum and maximum values given in the arrays
 * table->extra1 and table->extra2, respectively.
 */
int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen, void **context)
{

        if (newval && newlen) {
                int __user *vec = (int __user *) newval;
                int *min = (int *) table->extra1;
                int *max = (int *) table->extra2;
                size_t length;
                int i;

                if (newlen % sizeof(int) != 0)
                        return -EINVAL;

                if (!table->extra1 && !table->extra2)
                        return 0;

                if (newlen > table->maxlen)
                        newlen = table->maxlen;
                length = newlen / sizeof(int);

                for (i = 0; i < length; i++) {
                        int value;
                        if (get_user(value, vec + i))
                                return -EFAULT;
                        if (min && value < min[i])
                                return -EINVAL;
                        if (max && value > max[i])
                                return -EINVAL;
                }
        }
        return 0;
}

/* Strategy function to convert jiffies to seconds */ 
int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen, void **context)
{
        if (oldval) {
                size_t olen;
                if (oldlenp) { 
                        if (get_user(olen, oldlenp))
                                return -EFAULT;
                        if (olen!=sizeof(int))
                                return -EINVAL; 
                }
                if (put_user(*(int *)(table->data)/HZ, (int __user *)oldval) ||
                    (oldlenp && put_user(sizeof(int),oldlenp)))
                        return -EFAULT;
        }
        if (newval && newlen) { 
                int new;
                if (newlen != sizeof(int))
                        return -EINVAL; 
                if (get_user(new, (int __user *)newval))
                        return -EFAULT;
                *(int *)(table->data) = new*HZ; 
        }
        return 1;
}


#else /* CONFIG_SYSCTL */


asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
{
        return -ENOSYS;
}

int sysctl_string(ctl_table *table, int __user *name, int nlen,
                  void __user *oldval, size_t __user *oldlenp,
                  void __user *newval, size_t newlen, void **context)
{
        return -ENOSYS;
}

int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen, void **context)
{
        return -ENOSYS;
}

int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen, void **context)
{
        return -ENOSYS;
}

int proc_dostring(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec(ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
                        void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
                    void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
                          void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
                          void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
                    void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return -ENOSYS;
}

int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
                                      struct file *filp,
                                      void __user *buffer,
                                      size_t *lenp, loff_t *ppos)
{
    return -ENOSYS;
}

struct ctl_table_header * register_sysctl_table(ctl_table * table, 
                                                int insert_at_head)
{
        return NULL;
}

void unregister_sysctl_table(struct ctl_table_header * table)
{
}

#endif /* CONFIG_SYSCTL */

/*
 * No sense putting this after each symbol definition, twice,
 * exception granted :-)
 */
EXPORT_SYMBOL(proc_dointvec);
EXPORT_SYMBOL(proc_dointvec_jiffies);
EXPORT_SYMBOL(proc_dointvec_minmax);
EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
EXPORT_SYMBOL(proc_dostring);
EXPORT_SYMBOL(proc_doulongvec_minmax);
EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
EXPORT_SYMBOL(register_sysctl_table);
EXPORT_SYMBOL(sysctl_intvec);
EXPORT_SYMBOL(sysctl_jiffies);
EXPORT_SYMBOL(sysctl_string);
EXPORT_SYMBOL(unregister_sysctl_table);