/*
 * 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/module.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/signal.h>
#include <linux/printk.h>
#include <linux/proc_fs.h>
#include <linux/security.h>
#include <linux/ctype.h>
#include <linux/kmemcheck.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/net.h>
#include <linux/sysrq.h>
#include <linux/highuid.h>
#include <linux/writeback.h>
#include <linux/ratelimit.h>
#include <linux/compaction.h>
#include <linux/hugetlb.h>
#include <linux/initrd.h>
#include <linux/key.h>
#include <linux/times.h>
#include <linux/limits.h>
#include <linux/dcache.h>
#include <linux/dnotify.h>
#include <linux/syscalls.h>
#include <linux/vmstat.h>
#include <linux/nfs_fs.h>
#include <linux/acpi.h>
#include <linux/reboot.h>
#include <linux/ftrace.h>
#include <linux/perf_event.h>
#include <linux/kprobes.h>
#include <linux/pipe_fs_i.h>
#include <linux/oom.h>

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

#ifdef CONFIG_X86
#include <asm/nmi.h>
#include <asm/stacktrace.h>
#include <asm/io.h>
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
#include <linux/acct.h>
#endif
#ifdef CONFIG_RT_MUTEXES
#include <linux/rtmutex.h>
#endif
#if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_LOCK_STAT)
#include <linux/lockdep.h>
#endif
#ifdef CONFIG_CHR_DEV_SG
#include <scsi/sg.h>
#endif

#ifdef CONFIG_LOCKUP_DETECTOR
#include <linux/nmi.h>
#endif


#if defined(CONFIG_SYSCTL)

/* External variables not in a header file. */
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern int max_threads;
extern int core_uses_pid;
extern int suid_dumpable;
extern char core_pattern[];
extern unsigned int core_pipe_limit;
extern int pid_max;
extern int min_free_kbytes;
extern int pid_max_min, pid_max_max;
extern int sysctl_drop_caches;
extern int percpu_pagelist_fraction;
extern int compat_log;
extern int latencytop_enabled;
extern int sysctl_nr_open_min, sysctl_nr_open_max;
#ifndef CONFIG_MMU
extern int sysctl_nr_trim_pages;
#endif
#ifdef CONFIG_BLOCK
extern int blk_iopoll_enabled;
#endif

/* Constants used for minimum and  maximum */
#ifdef CONFIG_LOCKUP_DETECTOR
static int sixty = 60;
static int neg_one = -1;
#endif

static int zero;
static int __maybe_unused one = 1;
static int __maybe_unused two = 2;
static int __maybe_unused three = 3;
static unsigned long one_ul = 1;
static int one_hundred = 100;
#ifdef CONFIG_PRINTK
static int ten_thousand = 10000;
#endif

/* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;

/* 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_INOTIFY_USER
#include <linux/inotify.h>
#endif
#ifdef CONFIG_SPARC
#include <asm/system.h>
#endif

#ifdef CONFIG_SPARC64
extern int sysctl_tsb_ratio;
#endif

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

#ifdef CONFIG_S390
#ifdef CONFIG_MATHEMU
extern int sysctl_ieee_emulation_warnings;
#endif
extern int sysctl_userprocess_debug;
extern int spin_retry;
#endif

#ifdef CONFIG_IA64
extern int no_unaligned_warning;
extern int unaligned_dump_stack;
#endif

#ifdef CONFIG_PROC_SYSCTL
static int proc_do_cad_pid(struct ctl_table *table, int write,
                  void __user *buffer, size_t *lenp, loff_t *ppos);
static int proc_taint(struct ctl_table *table, int write,
                               void __user *buffer, size_t *lenp, loff_t *ppos);
#endif

#ifdef CONFIG_PRINTK
static int proc_dmesg_restrict(struct ctl_table *table, int write,
                                void __user *buffer, size_t *lenp, loff_t *ppos);
#endif

#ifdef CONFIG_MAGIC_SYSRQ
/* Note: sysrq code uses it's own private copy */
static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE;

static int sysrq_sysctl_handler(ctl_table *table, int write,
                                void __user *buffer, size_t *lenp,
                                loff_t *ppos)
{
        int error;

        error = proc_dointvec(table, write, buffer, lenp, ppos);
        if (error)
                return error;

        if (write)
                sysrq_toggle_support(__sysrq_enabled);

        return 0;
}

#endif

static struct ctl_table root_table[];
static struct ctl_table_root sysctl_table_root;
static struct ctl_table_header root_table_header = {
        {{.count = 1,
        .ctl_table = root_table,
        .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),}},
        .root = &sysctl_table_root,
        .set = &sysctl_table_root.default_set,
};
static struct ctl_table_root sysctl_table_root = {
        .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
        .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
};

static struct ctl_table kern_table[];
static struct ctl_table vm_table[];
static struct ctl_table fs_table[];
static struct ctl_table debug_table[];
static struct ctl_table dev_table[];
extern struct ctl_table random_table[];
#ifdef CONFIG_EPOLL
extern struct ctl_table epoll_table[];
#endif

#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
int sysctl_legacy_va_layout;
#endif

/* The default sysctl tables: */

static struct ctl_table root_table[] = {
        {
                .procname       = "kernel",
                .mode           = 0555,
                .child          = kern_table,
        },
        {
                .procname       = "vm",
                .mode           = 0555,
                .child          = vm_table,
        },
        {
                .procname       = "fs",
                .mode           = 0555,
                .child          = fs_table,
        },
        {
                .procname       = "debug",
                .mode           = 0555,
                .child          = debug_table,
        },
        {
                .procname       = "dev",
                .mode           = 0555,
                .child          = dev_table,
        },
        { }
};

#ifdef CONFIG_SCHED_DEBUG
static int min_sched_granularity_ns = 100000;           /* 100 usecs */
static int max_sched_granularity_ns = NSEC_PER_SEC;     /* 1 second */
static int min_wakeup_granularity_ns;                   /* 0 usecs */
static int max_wakeup_granularity_ns = NSEC_PER_SEC;    /* 1 second */
static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
#endif

#ifdef CONFIG_COMPACTION
static int min_extfrag_threshold;
static int max_extfrag_threshold = 1000;
#endif

static struct ctl_table kern_table[] = {
        {
                .procname       = "sched_child_runs_first",
                .data           = &sysctl_sched_child_runs_first,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#ifdef CONFIG_SCHED_DEBUG
        {
                .procname       = "sched_min_granularity_ns",
                .data           = &sysctl_sched_min_granularity,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = sched_proc_update_handler,
                .extra1         = &min_sched_granularity_ns,
                .extra2         = &max_sched_granularity_ns,
        },
        {
                .procname       = "sched_latency_ns",
                .data           = &sysctl_sched_latency,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = sched_proc_update_handler,
                .extra1         = &min_sched_granularity_ns,
                .extra2         = &max_sched_granularity_ns,
        },
        {
                .procname       = "sched_wakeup_granularity_ns",
                .data           = &sysctl_sched_wakeup_granularity,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = sched_proc_update_handler,
                .extra1         = &min_wakeup_granularity_ns,
                .extra2         = &max_wakeup_granularity_ns,
        },
        {
                .procname       = "sched_tunable_scaling",
                .data           = &sysctl_sched_tunable_scaling,
                .maxlen         = sizeof(enum sched_tunable_scaling),
                .mode           = 0644,
                .proc_handler   = sched_proc_update_handler,
                .extra1         = &min_sched_tunable_scaling,
                .extra2         = &max_sched_tunable_scaling,
        },
        {
                .procname       = "sched_migration_cost",
                .data           = &sysctl_sched_migration_cost,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "sched_nr_migrate",
                .data           = &sysctl_sched_nr_migrate,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "sched_time_avg",
                .data           = &sysctl_sched_time_avg,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "sched_shares_window",
                .data           = &sysctl_sched_shares_window,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "timer_migration",
                .data           = &sysctl_timer_migration,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
#endif
        {
                .procname       = "sched_rt_period_us",
                .data           = &sysctl_sched_rt_period,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = sched_rt_handler,
        },
        {
                .procname       = "sched_rt_runtime_us",
                .data           = &sysctl_sched_rt_runtime,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = sched_rt_handler,
        },
#ifdef CONFIG_SCHED_AUTOGROUP
        {
                .procname       = "sched_autogroup_enabled",
                .data           = &sysctl_sched_autogroup_enabled,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
#endif
#ifdef CONFIG_PROVE_LOCKING
        {
                .procname       = "prove_locking",
                .data           = &prove_locking,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_LOCK_STAT
        {
                .procname       = "lock_stat",
                .data           = &lock_stat,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "panic",
                .data           = &panic_timeout,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "core_uses_pid",
                .data           = &core_uses_pid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "core_pattern",
                .data           = core_pattern,
                .maxlen         = CORENAME_MAX_SIZE,
                .mode           = 0644,
                .proc_handler   = proc_dostring,
        },
        {
                .procname       = "core_pipe_limit",
                .data           = &core_pipe_limit,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#ifdef CONFIG_PROC_SYSCTL
        {
                .procname       = "tainted",
                .maxlen         = sizeof(long),
                .mode           = 0644,
                .proc_handler   = proc_taint,
        },
#endif
#ifdef CONFIG_LATENCYTOP
        {
                .procname       = "latencytop",
                .data           = &latencytop_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_BLK_DEV_INITRD
        {
                .procname       = "real-root-dev",
                .data           = &real_root_dev,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "print-fatal-signals",
                .data           = &print_fatal_signals,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#ifdef CONFIG_SPARC
        {
                .procname       = "reboot-cmd",
                .data           = reboot_command,
                .maxlen         = 256,
                .mode           = 0644,
                .proc_handler   = proc_dostring,
        },
        {
                .procname       = "stop-a",
                .data           = &stop_a_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "scons-poweroff",
                .data           = &scons_pwroff,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_SPARC64
        {
                .procname       = "tsb-ratio",
                .data           = &sysctl_tsb_ratio,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef __hppa__
        {
                .procname       = "soft-power",
                .data           = &pwrsw_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "unaligned-trap",
                .data           = &unaligned_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "ctrl-alt-del",
                .data           = &C_A_D,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#ifdef CONFIG_FUNCTION_TRACER
        {
                .procname       = "ftrace_enabled",
                .data           = &ftrace_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = ftrace_enable_sysctl,
        },
#endif
#ifdef CONFIG_STACK_TRACER
        {
                .procname       = "stack_tracer_enabled",
                .data           = &stack_tracer_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = stack_trace_sysctl,
        },
#endif
#ifdef CONFIG_TRACING
        {
                .procname       = "ftrace_dump_on_oops",
                .data           = &ftrace_dump_on_oops,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_MODULES
        {
                .procname       = "modprobe",
                .data           = &modprobe_path,
                .maxlen         = KMOD_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = proc_dostring,
        },
        {
                .procname       = "modules_disabled",
                .data           = &modules_disabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                /* only handle a transition from default "0" to "1" */
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &one,
                .extra2         = &one,
        },
#endif
#ifdef CONFIG_HOTPLUG
        {
                .procname       = "hotplug",
                .data           = &uevent_helper,
                .maxlen         = UEVENT_HELPER_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = proc_dostring,
        },
#endif
#ifdef CONFIG_CHR_DEV_SG
        {
                .procname       = "sg-big-buff",
                .data           = &sg_big_buff,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
        {
                .procname       = "acct",
                .data           = &acct_parm,
                .maxlen         = 3*sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_MAGIC_SYSRQ
        {
                .procname       = "sysrq",
                .data           = &__sysrq_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = sysrq_sysctl_handler,
        },
#endif
#ifdef CONFIG_PROC_SYSCTL
        {
                .procname       = "cad_pid",
                .data           = NULL,
                .maxlen         = sizeof (int),
                .mode           = 0600,
                .proc_handler   = proc_do_cad_pid,
        },
#endif
        {
                .procname       = "threads-max",
                .data           = &max_threads,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "random",
                .mode           = 0555,
                .child          = random_table,
        },
        {
                .procname       = "overflowuid",
                .data           = &overflowuid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .procname       = "overflowgid",
                .data           = &overflowgid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
#ifdef CONFIG_S390
#ifdef CONFIG_MATHEMU
        {
                .procname       = "ieee_emulation_warnings",
                .data           = &sysctl_ieee_emulation_warnings,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "userprocess_debug",
                .data           = &show_unhandled_signals,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "pid_max",
                .data           = &pid_max,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &pid_max_min,
                .extra2         = &pid_max_max,
        },
        {
                .procname       = "panic_on_oops",
                .data           = &panic_on_oops,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#if defined CONFIG_PRINTK
        {
                .procname       = "printk",
                .data           = &console_loglevel,
                .maxlen         = 4*sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "printk_ratelimit",
                .data           = &printk_ratelimit_state.interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "printk_ratelimit_burst",
                .data           = &printk_ratelimit_state.burst,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "printk_delay",
                .data           = &printk_delay_msec,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &ten_thousand,
        },
        {
                .procname       = "dmesg_restrict",
                .data           = &dmesg_restrict,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
        {
                .procname       = "kptr_restrict",
                .data           = &kptr_restrict,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dmesg_restrict,
                .extra1         = &zero,
                .extra2         = &two,
        },
#endif
        {
                .procname       = "ngroups_max",
                .data           = &ngroups_max,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
#if defined(CONFIG_LOCKUP_DETECTOR)
        {
                .procname       = "watchdog",
                .data           = &watchdog_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dowatchdog_enabled,
        },
        {
                .procname       = "watchdog_thresh",
                .data           = &softlockup_thresh,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dowatchdog_thresh,
                .extra1         = &neg_one,
                .extra2         = &sixty,
        },
        {
                .procname       = "softlockup_panic",
                .data           = &softlockup_panic,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
        {
                .procname       = "nmi_watchdog",
                .data           = &watchdog_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dowatchdog_enabled,
        },
#endif
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
        {
                .procname       = "unknown_nmi_panic",
                .data           = &unknown_nmi_panic,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#if defined(CONFIG_X86)
        {
                .procname       = "panic_on_unrecovered_nmi",
                .data           = &panic_on_unrecovered_nmi,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "panic_on_io_nmi",
                .data           = &panic_on_io_nmi,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "bootloader_type",
                .data           = &bootloader_type,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "bootloader_version",
                .data           = &bootloader_version,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "kstack_depth_to_print",
                .data           = &kstack_depth_to_print,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "io_delay_type",
                .data           = &io_delay_type,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#if defined(CONFIG_MMU)
        {
                .procname       = "randomize_va_space",
                .data           = &randomize_va_space,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#if defined(CONFIG_S390) && defined(CONFIG_SMP)
        {
                .procname       = "spin_retry",
                .data           = &spin_retry,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#if     defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
        {
                .procname       = "acpi_video_flags",
                .data           = &acpi_realmode_flags,
                .maxlen         = sizeof (unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
        },
#endif
#ifdef CONFIG_IA64
        {
                .procname       = "ignore-unaligned-usertrap",
                .data           = &no_unaligned_warning,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "unaligned-dump-stack",
                .data           = &unaligned_dump_stack,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_DETECT_HUNG_TASK
        {
                .procname       = "hung_task_panic",
                .data           = &sysctl_hung_task_panic,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
        {
                .procname       = "hung_task_check_count",
                .data           = &sysctl_hung_task_check_count,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
        },
        {
                .procname       = "hung_task_timeout_secs",
                .data           = &sysctl_hung_task_timeout_secs,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_dohung_task_timeout_secs,
        },
        {
                .procname       = "hung_task_warnings",
                .data           = &sysctl_hung_task_warnings,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
        },
#endif
#ifdef CONFIG_COMPAT
        {
                .procname       = "compat-log",
                .data           = &compat_log,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_RT_MUTEXES
        {
                .procname       = "max_lock_depth",
                .data           = &max_lock_depth,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        {
                .procname       = "poweroff_cmd",
                .data           = &poweroff_cmd,
                .maxlen         = POWEROFF_CMD_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = proc_dostring,
        },
#ifdef CONFIG_KEYS
        {
                .procname       = "keys",
                .mode           = 0555,
                .child          = key_sysctls,
        },
#endif
#ifdef CONFIG_RCU_TORTURE_TEST
        {
                .procname       = "rcutorture_runnable",
                .data           = &rcutorture_runnable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_PERF_EVENTS
        {
                .procname       = "perf_event_paranoid",
                .data           = &sysctl_perf_event_paranoid,
                .maxlen         = sizeof(sysctl_perf_event_paranoid),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "perf_event_mlock_kb",
                .data           = &sysctl_perf_event_mlock,
                .maxlen         = sizeof(sysctl_perf_event_mlock),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "perf_event_max_sample_rate",
                .data           = &sysctl_perf_event_sample_rate,
                .maxlen         = sizeof(sysctl_perf_event_sample_rate),
                .mode           = 0644,
                .proc_handler   = perf_proc_update_handler,
        },
#endif
#ifdef CONFIG_KMEMCHECK
        {
                .procname       = "kmemcheck",
                .data           = &kmemcheck_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_BLOCK
        {
                .procname       = "blk_iopoll",
                .data           = &blk_iopoll_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
        { }
};

static struct ctl_table vm_table[] = {
        {
                .procname       = "overcommit_memory",
                .data           = &sysctl_overcommit_memory,
                .maxlen         = sizeof(sysctl_overcommit_memory),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &two,
        },
        {
                .procname       = "panic_on_oom",
                .data           = &sysctl_panic_on_oom,
                .maxlen         = sizeof(sysctl_panic_on_oom),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &two,
        },
        {
                .procname       = "oom_kill_allocating_task",
                .data           = &sysctl_oom_kill_allocating_task,
                .maxlen         = sizeof(sysctl_oom_kill_allocating_task),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {

                .procname       = "oom_dump_tasks",
                .data           = &sysctl_oom_dump_tasks,
                .maxlen         = sizeof(sysctl_oom_dump_tasks),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "overcommit_ratio",
                .data           = &sysctl_overcommit_ratio,
                .maxlen         = sizeof(sysctl_overcommit_ratio),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "page-cluster", 
                .data           = &page_cluster,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
        },
        {
                .procname       = "dirty_background_ratio",
                .data           = &dirty_background_ratio,
                .maxlen         = sizeof(dirty_background_ratio),
                .mode           = 0644,
                .proc_handler   = dirty_background_ratio_handler,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .procname       = "dirty_background_bytes",
                .data           = &dirty_background_bytes,
                .maxlen         = sizeof(dirty_background_bytes),
                .mode           = 0644,
                .proc_handler   = dirty_background_bytes_handler,
                .extra1         = &one_ul,
        },
        {
                .procname       = "dirty_ratio",
                .data           = &vm_dirty_ratio,
                .maxlen         = sizeof(vm_dirty_ratio),
                .mode           = 0644,
                .proc_handler   = dirty_ratio_handler,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .procname       = "dirty_bytes",
                .data           = &vm_dirty_bytes,
                .maxlen         = sizeof(vm_dirty_bytes),
                .mode           = 0644,
                .proc_handler   = dirty_bytes_handler,
                .extra1         = &dirty_bytes_min,
        },
        {
                .procname       = "dirty_writeback_centisecs",
                .data           = &dirty_writeback_interval,
                .maxlen         = sizeof(dirty_writeback_interval),
                .mode           = 0644,
                .proc_handler   = dirty_writeback_centisecs_handler,
        },
        {
                .procname       = "dirty_expire_centisecs",
                .data           = &dirty_expire_interval,
                .maxlen         = sizeof(dirty_expire_interval),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
        },
        {
                .procname       = "nr_pdflush_threads",
                .data           = &nr_pdflush_threads,
                .maxlen         = sizeof nr_pdflush_threads,
                .mode           = 0444 /* read-only*/,
                .proc_handler   = proc_dointvec,
        },
        {
                .procname       = "swappiness",
                .data           = &vm_swappiness,
                .maxlen         = sizeof(vm_swappiness),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
#ifdef CONFIG_HUGETLB_PAGE
        {
                .procname       = "nr_hugepages",
                .data           = NULL,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = hugetlb_sysctl_handler,
                .extra1         = (void *)&hugetlb_zero,
                .extra2         = (void *)&hugetlb_infinity,
        },
#ifdef CONFIG_NUMA
        {
                .procname       = "nr_hugepages_mempolicy",
                .data           = NULL,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &hugetlb_mempolicy_sysctl_handler,
                .extra1         = (void *)&hugetlb_zero,
                .extra2         = (void *)&hugetlb_infinity,
        },
#endif
         {
                .procname       = "hugetlb_shm_group",
                .data           = &sysctl_hugetlb_shm_group,
                .maxlen         = sizeof(gid_t),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
         },
         {
                .procname       = "hugepages_treat_as_movable",
                .data           = &hugepages_treat_as_movable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = hugetlb_treat_movable_handler,
        },
        {
                .procname       = "nr_overcommit_hugepages",
                .data           = NULL,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = hugetlb_overcommit_handler,
                .extra1         = (void *)&hugetlb_zero,
                .extra2         = (void *)&hugetlb_infinity,
        },
#endif
        {
                .procname       = "lowmem_reserve_ratio",
                .data           = &sysctl_lowmem_reserve_ratio,
                .maxlen         = sizeof(sysctl_lowmem_reserve_ratio),
                .mode           = 0644,
                .proc_handler   = lowmem_reserve_ratio_sysctl_handler,
        },
        {
                .procname       = "drop_caches",
                .data           = &sysctl_drop_caches,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = drop_caches_sysctl_handler,
                .extra1         = &one,
                .extra2         = &three,
        },
#ifdef CONFIG_COMPACTION
        {
                .procname       = "compact_memory",
                .data           = &sysctl_compact_memory,
                .maxlen         = sizeof(int),
                .mode           = 0200,
                .proc_handler   = sysctl_compaction_handler,
        },
        {
                .procname       = "extfrag_threshold",
                .data           = &sysctl_extfrag_threshold,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = sysctl_extfrag_handler,
                .extra1         = &min_extfrag_threshold,
                .extra2         = &max_extfrag_threshold,
        },

#endif /* CONFIG_COMPACTION */
        {
                .procname       = "min_free_kbytes",
                .data           = &min_free_kbytes,
                .maxlen         = sizeof(min_free_kbytes),
                .mode           = 0644,
                .proc_handler   = min_free_kbytes_sysctl_handler,
                .extra1         = &zero,
        },
        {
                .procname       = "percpu_pagelist_fraction",
                .data           = &percpu_pagelist_fraction,
                .maxlen         = sizeof(percpu_pagelist_fraction),
                .mode           = 0644,
                .proc_handler   = percpu_pagelist_fraction_sysctl_handler,
                .extra1         = &min_percpu_pagelist_fract,
        },
#ifdef CONFIG_MMU
        {
                .procname       = "max_map_count",
                .data           = &sysctl_max_map_count,
                .maxlen         = sizeof(sysctl_max_map_count),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
        },
#else
        {
                .procname       = "nr_trim_pages",
                .data           = &sysctl_nr_trim_pages,
                .maxlen         = sizeof(sysctl_nr_trim_pages),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
        },
#endif
        {
                .procname       = "laptop_mode",
                .data           = &laptop_mode,
                .maxlen         = sizeof(laptop_mode),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
        {
                .procname       = "block_dump",
                .data           = &block_dump,
                .maxlen         = sizeof(block_dump),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
                .extra1         = &zero,
        },
        {
                .procname       = "vfs_cache_pressure",
                .data           = &sysctl_vfs_cache_pressure,
                .maxlen         = sizeof(sysctl_vfs_cache_pressure),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
                .extra1         = &zero,
        },
#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
        {
                .procname       = "legacy_va_layout",
                .data           = &sysctl_legacy_va_layout,
                .maxlen         = sizeof(sysctl_legacy_va_layout),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
                .extra1         = &zero,
        },
#endif
#ifdef CONFIG_NUMA
        {
                .procname       = "zone_reclaim_mode",
                .data           = &zone_reclaim_mode,
                .maxlen         = sizeof(zone_reclaim_mode),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
                .extra1         = &zero,
        },
        {
                .procname       = "min_unmapped_ratio",
                .data           = &sysctl_min_unmapped_ratio,
                .maxlen         = sizeof(sysctl_min_unmapped_ratio),
                .mode           = 0644,
                .proc_handler   = sysctl_min_unmapped_ratio_sysctl_handler,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .procname       = "min_slab_ratio",
                .data           = &sysctl_min_slab_ratio,
                .maxlen         = sizeof(sysctl_min_slab_ratio),
                .mode           = 0644,
                .proc_handler   = sysctl_min_slab_ratio_sysctl_handler,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
#endif
#ifdef CONFIG_SMP
        {
                .procname       = "stat_interval",
                .data           = &sysctl_stat_interval,
                .maxlen         = sizeof(sysctl_stat_interval),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
#endif
#ifdef CONFIG_MMU
        {
                .procname       = "mmap_min_addr",
                .data           = &dac_mmap_min_addr,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = mmap_min_addr_handler,
        },
#endif
#ifdef CONFIG_NUMA
        {
                .procname       = "numa_zonelist_order",
                .data           = &numa_zonelist_order,
                .maxlen         = NUMA_ZONELIST_ORDER_LEN,
                .mode           = 0644,
                .proc_handler   = numa_zonelist_order_handler,
        },
#endif
#if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
   (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
        {
                .procname       = "vdso_enabled",
                .data           = &vdso_enabled,
                .maxlen         = sizeof(vdso_enabled),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
                .extra1         = &zero,
        },
#endif
#ifdef CONFIG_HIGHMEM
        {
                .procname       = "highmem_is_dirtyable",
                .data           = &vm_highmem_is_dirtyable,
                .maxlen         = sizeof(vm_highmem_is_dirtyable),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
#endif
        {
                .procname       = "scan_unevictable_pages",
                .data           = &scan_unevictable_pages,
                .maxlen         = sizeof(scan_unevictable_pages),
                .mode           = 0644,
                .proc_handler   = scan_unevictable_handler,
        },
#ifdef CONFIG_MEMORY_FAILURE
        {
                .procname       = "memory_failure_early_kill",
                .data           = &sysctl_memory_failure_early_kill,
                .maxlen         = sizeof(sysctl_memory_failure_early_kill),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
        {
                .procname       = "memory_failure_recovery",
                .data           = &sysctl_memory_failure_recovery,
                .maxlen         = sizeof(sysctl_memory_failure_recovery),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &one,
        },
#endif
        { }
};

#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
static struct ctl_table binfmt_misc_table[] = {
        { }
};
#endif

static struct ctl_table fs_table[] = {
        {
                .procname       = "inode-nr",
                .data           = &inodes_stat,
                .maxlen         = 2*sizeof(int),
                .mode           = 0444,
                .proc_handler   = proc_nr_inodes,
        },
        {
                .procname       = "inode-state",
                .data           = &inodes_stat,
                .maxlen         = 7*sizeof(int),
                .mode           = 0444,
                .proc_handler   = proc_nr_inodes,
        },
        {
                .procname       = "file-nr",
                .data           = &files_stat,
                .maxlen         = sizeof(files_stat),
                .mode           = 0444,
                .proc_handler   = proc_nr_files,
        },
        {
                .procname       = "file-max",
                .data           = &files_stat.max_files,
                .maxlen         = sizeof(files_stat.max_files),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
        },
        {
                .procname       = "nr_open",
                .data           = &sysctl_nr_open,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &sysctl_nr_open_min,
                .extra2         = &sysctl_nr_open_max,
        },
        {
                .procname       = "dentry-state",
                .data           = &dentry_stat,
                .maxlen         = 6*sizeof(int),
                .mode           = 0444,
                .proc_handler   = proc_nr_dentry,
        },
        {
                .procname       = "overflowuid",
                .data           = &fs_overflowuid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .procname       = "overflowgid",
                .data           = &fs_overflowgid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
#ifdef CONFIG_FILE_LOCKING
        {
                .procname       = "leases-enable",
                .data           = &leases_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_DNOTIFY
        {
                .procname       = "dir-notify-enable",
                .data           = &dir_notify_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_MMU
#ifdef CONFIG_FILE_LOCKING
        {
                .procname       = "lease-break-time",
                .data           = &lease_break_time,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
#endif
#ifdef CONFIG_AIO
        {
                .procname       = "aio-nr",
                .data           = &aio_nr,
                .maxlen         = sizeof(aio_nr),
                .mode           = 0444,
                .proc_handler   = proc_doulongvec_minmax,
        },
        {
                .procname       = "aio-max-nr",
                .data           = &aio_max_nr,
                .maxlen         = sizeof(aio_max_nr),
                .mode           = 0644,
                .proc_handler   = proc_doulongvec_minmax,
        },
#endif /* CONFIG_AIO */
#ifdef CONFIG_INOTIFY_USER
        {
                .procname       = "inotify",
                .mode           = 0555,
                .child          = inotify_table,
        },
#endif  
#ifdef CONFIG_EPOLL
        {
                .procname       = "epoll",
                .mode           = 0555,
                .child          = epoll_table,
        },
#endif
#endif
        {
                .procname       = "suid_dumpable",
                .data           = &suid_dumpable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &zero,
                .extra2         = &two,
        },
#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
        {
                .procname       = "binfmt_misc",
                .mode           = 0555,
                .child          = binfmt_misc_table,
        },
#endif
        {
                .procname       = "pipe-max-size",
                .data           = &pipe_max_size,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &pipe_proc_fn,
                .extra1         = &pipe_min_size,
        },
        { }
};

static struct ctl_table debug_table[] = {
#if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_SPARC) || \
    defined(CONFIG_S390)
        {
                .procname       = "exception-trace",
                .data           = &show_unhandled_signals,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec
        },
#endif
#if defined(CONFIG_OPTPROBES)
        {
                .procname       = "kprobes-optimization",
                .data           = &sysctl_kprobes_optimization,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_kprobes_optimization_handler,
                .extra1         = &zero,
                .extra2         = &one,
        },
#endif
        { }
};

static struct ctl_table dev_table[] = {
        { }
};

static DEFINE_SPINLOCK(sysctl_lock);

/* 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)
{
        /*
         * if p->used is 0, nobody will ever touch that entry again;
         * we'll eliminate all paths to it before dropping sysctl_lock
         */
        if (unlikely(p->used)) {
                struct completion wait;
                init_completion(&wait);
                p->unregistering = &wait;
                spin_unlock(&sysctl_lock);
                wait_for_completion(&wait);
                spin_lock(&sysctl_lock);
        } else {
                /* anything non-NULL; we'll never dereference it */
                p->unregistering = ERR_PTR(-EINVAL);
        }
        /*
         * 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 sysctl_head_get(struct ctl_table_header *head)
{
        spin_lock(&sysctl_lock);
        head->count++;
        spin_unlock(&sysctl_lock);
}

static void free_head(struct rcu_head *rcu)
{
        kfree(container_of(rcu, struct ctl_table_header, rcu));
}

void sysctl_head_put(struct ctl_table_header *head)
{
        spin_lock(&sysctl_lock);
        if (!--head->count)
                call_rcu(&head->rcu, free_head);
        spin_unlock(&sysctl_lock);
}

struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
{
        if (!head)
                BUG();
        spin_lock(&sysctl_lock);
        if (!use_table(head))
                head = ERR_PTR(-ENOENT);
        spin_unlock(&sysctl_lock);
        return head;
}

void sysctl_head_finish(struct ctl_table_header *head)
{
        if (!head)
                return;
        spin_lock(&sysctl_lock);
        unuse_table(head);
        spin_unlock(&sysctl_lock);
}

static struct ctl_table_set *
lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
{
        struct ctl_table_set *set = &root->default_set;
        if (root->lookup)
                set = root->lookup(root, namespaces);
        return set;
}

static struct list_head *
lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
{
        struct ctl_table_set *set = lookup_header_set(root, namespaces);
        return &set->list;
}

struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
                                            struct ctl_table_header *prev)
{
        struct ctl_table_root *root;
        struct list_head *header_list;
        struct ctl_table_header *head;
        struct list_head *tmp;

        spin_lock(&sysctl_lock);
        if (prev) {
                head = prev;
                tmp = &prev->ctl_entry;
                unuse_table(prev);
                goto next;
        }
        tmp = &root_table_header.ctl_entry;
        for (;;) {
                head = list_entry(tmp, struct ctl_table_header, ctl_entry);

                if (!use_table(head))
                        goto next;
                spin_unlock(&sysctl_lock);
                return head;
        next:
                root = head->root;
                tmp = tmp->next;
                header_list = lookup_header_list(root, namespaces);
                if (tmp != header_list)
                        continue;

                do {
                        root = list_entry(root->root_list.next,
                                        struct ctl_table_root, root_list);
                        if (root == &sysctl_table_root)
                                goto out;
                        header_list = lookup_header_list(root, namespaces);
                } while (list_empty(header_list));
                tmp = header_list->next;
        }
out:
        spin_unlock(&sysctl_lock);
        return NULL;
}

struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
{
        return __sysctl_head_next(current->nsproxy, prev);
}

void register_sysctl_root(struct ctl_table_root *root)
{
        spin_lock(&sysctl_lock);
        list_add_tail(&root->root_list, &sysctl_table_root.root_list);
        spin_unlock(&sysctl_lock);
}

/*
 * sysctl_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 ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
                return 0;
        return -EACCES;
}

int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
{
        int mode;

        if (root->permissions)
                mode = root->permissions(root, current->nsproxy, table);
        else
                mode = table->mode;

        return test_perm(mode, op);
}

static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
{
        for (; table->procname; table++) {
                table->parent = parent;
                if (table->child)
                        sysctl_set_parent(table, table->child);
        }
}

static __init int sysctl_init(void)
{
        sysctl_set_parent(NULL, root_table);
#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
        sysctl_check_table(current->nsproxy, root_table);
#endif
        return 0;
}

core_initcall(sysctl_init);

static struct ctl_table *is_branch_in(struct ctl_table *branch,
                                      struct ctl_table *table)
{
        struct ctl_table *p;
        const char *s = branch->procname;

        /* branch should have named subdirectory as its first element */
        if (!s || !branch->child)
                return NULL;

        /* ... and nothing else */
        if (branch[1].procname)
                return NULL;

        /* table should contain subdirectory with the same name */
        for (p = table; p->procname; p++) {
                if (!p->child)
                        continue;
                if (p->procname && strcmp(p->procname, s) == 0)
                        return p;
        }
        return NULL;
}

/* see if attaching q to p would be an improvement */
static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
{
        struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
        struct ctl_table *next;
        int is_better = 0;
        int not_in_parent = !p->attached_by;

        while ((next = is_branch_in(by, to)) != NULL) {
                if (by == q->attached_by)
                        is_better = 1;
                if (to == p->attached_by)
                        not_in_parent = 1;
                by = by->child;
                to = next->child;
        }

        if (is_better && not_in_parent) {
                q->attached_by = by;
                q->attached_to = to;
                q->parent = p;
        }
}

/**
 * __register_sysctl_paths - register a sysctl hierarchy
 * @root: List of sysctl headers to register on
 * @namespaces: Data to compute which lists of sysctl entries are visible
 * @path: The path to the directory the sysctl table is in.
 * @table: the top-level table structure
 *
 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
 * array. A completely 0 filled entry terminates the table.
 *
 * The members of the &struct ctl_table structure are used as follows:
 *
 * 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)
 *
 * 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.
 *
 * 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_paths(
        struct ctl_table_root *root,
        struct nsproxy *namespaces,
        const struct ctl_path *path, struct ctl_table *table)
{
        struct ctl_table_header *header;
        struct ctl_table *new, **prevp;
        unsigned int n, npath;
        struct ctl_table_set *set;

        /* Count the path components */
        for (npath = 0; path[npath].procname; ++npath)
                ;

        /*
         * For each path component, allocate a 2-element ctl_table array.
         * The first array element will be filled with the sysctl entry
         * for this, the second will be the sentinel (procname == 0).
         *
         * We allocate everything in one go so that we don't have to
         * worry about freeing additional memory in unregister_sysctl_table.
         */
        header = kzalloc(sizeof(struct ctl_table_header) +
                         (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
        if (!header)
                return NULL;

        new = (struct ctl_table *) (header + 1);

        /* Now connect the dots */
        prevp = &header->ctl_table;
        for (n = 0; n < npath; ++n, ++path) {
                /* Copy the procname */
                new->procname = path->procname;
                new->mode     = 0555;

                *prevp = new;
                prevp = &new->child;

                new += 2;
        }
        *prevp = table;
        header->ctl_table_arg = table;

        INIT_LIST_HEAD(&header->ctl_entry);
        header->used = 0;
        header->unregistering = NULL;
        header->root = root;
        sysctl_set_parent(NULL, header->ctl_table);
        header->count = 1;
#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
        if (sysctl_check_table(namespaces, header->ctl_table)) {
                kfree(header);
                return NULL;
        }
#endif
        spin_lock(&sysctl_lock);
        header->set = lookup_header_set(root, namespaces);
        header->attached_by = header->ctl_table;
        header->attached_to = root_table;
        header->parent = &root_table_header;
        for (set = header->set; set; set = set->parent) {
                struct ctl_table_header *p;
                list_for_each_entry(p, &set->list, ctl_entry) {
                        if (p->unregistering)
                                continue;
                        try_attach(p, header);
                }
        }
        header->parent->count++;
        list_add_tail(&header->ctl_entry, &header->set->list);
        spin_unlock(&sysctl_lock);

        return header;
}

/**
 * register_sysctl_table_path - register a sysctl table hierarchy
 * @path: The path to the directory the sysctl table is in.
 * @table: the top-level table structure
 *
 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
 * array. A completely 0 filled entry terminates the table.
 *
 * See __register_sysctl_paths for more details.
 */
struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
                                                struct ctl_table *table)
{
        return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
                                        path, table);
}

/**
 * register_sysctl_table - register a sysctl table hierarchy
 * @table: the top-level table structure
 *
 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
 * array. A completely 0 filled entry terminates the table.
 *
 * See register_sysctl_paths for more details.
 */
struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
{
        static const struct ctl_path null_path[] = { {} };

        return register_sysctl_paths(null_path, table);
}

/**
 * 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();

        if (header == NULL)
                return;

        spin_lock(&sysctl_lock);
        start_unregistering(header);
        if (!--header->parent->count) {
                WARN_ON(1);
                call_rcu(&header->parent->rcu, free_head);
        }
        if (!--header->count)
                call_rcu(&header->rcu, free_head);
        spin_unlock(&sysctl_lock);
}

int sysctl_is_seen(struct ctl_table_header *p)
{
        struct ctl_table_set *set = p->set;
        int res;
        spin_lock(&sysctl_lock);
        if (p->unregistering)
                res = 0;
        else if (!set->is_seen)
                res = 1;
        else
                res = set->is_seen(set);
        spin_unlock(&sysctl_lock);
        return res;
}

void setup_sysctl_set(struct ctl_table_set *p,
        struct ctl_table_set *parent,
        int (*is_seen)(struct ctl_table_set *))
{
        INIT_LIST_HEAD(&p->list);
        p->parent = parent ? parent : &sysctl_table_root.default_set;
        p->is_seen = is_seen;
}

#else /* !CONFIG_SYSCTL */
struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
{
        return NULL;
}

struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
                                                    struct ctl_table *table)
{
        return NULL;
}

void unregister_sysctl_table(struct ctl_table_header * table)
{
}

void setup_sysctl_set(struct ctl_table_set *p,
        struct ctl_table_set *parent,
        int (*is_seen)(struct ctl_table_set *))
{
}

void sysctl_head_put(struct ctl_table_header *head)
{
}

#endif /* CONFIG_SYSCTL */

/*
 * /proc/sys support
 */

#ifdef CONFIG_PROC_SYSCTL

static int _proc_do_string(void* data, int maxlen, int write,
                           void __user *buffer,
                           size_t *lenp, loff_t *ppos)
{
        size_t len;
        char __user *p;
        char c;

        if (!data || !maxlen || !*lenp) {
                *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 >= maxlen)
                        len = maxlen-1;
                if(copy_from_user(data, buffer, len))
                        return -EFAULT;
                ((char *) data)[len] = 0;
                *ppos += *lenp;
        } else {
                len = strlen(data);
                if (len > maxlen)
                        len = maxlen;

                if (*ppos > len) {
                        *lenp = 0;
                        return 0;
                }

                data += *ppos;
                len  -= *ppos;

                if (len > *lenp)
                        len = *lenp;
                if (len)
                        if(copy_to_user(buffer, data, len))
                                return -EFAULT;
                if (len < *lenp) {
                        if(put_user('\n', ((char __user *) buffer) + len))
                                return -EFAULT;
                        len++;
                }
                *lenp = len;
                *ppos += len;
        }
        return 0;
}

/**
 * proc_dostring - read a string sysctl
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * 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(struct ctl_table *table, int write,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return _proc_do_string(table->data, table->maxlen, write,
                               buffer, lenp, ppos);
}

static size_t proc_skip_spaces(char **buf)
{
        size_t ret;
        char *tmp = skip_spaces(*buf);
        ret = tmp - *buf;
        *buf = tmp;
        return ret;
}

static void proc_skip_char(char **buf, size_t *size, const char v)
{
        while (*size) {
                if (**buf != v)
                        break;
                (*size)--;
                (*buf)++;
        }
}

#define TMPBUFLEN 22
/**
 * proc_get_long - reads an ASCII formatted integer from a user buffer
 *
 * @buf: a kernel buffer
 * @size: size of the kernel buffer
 * @val: this is where the number will be stored
 * @neg: set to %TRUE if number is negative
 * @perm_tr: a vector which contains the allowed trailers
 * @perm_tr_len: size of the perm_tr vector
 * @tr: pointer to store the trailer character
 *
 * In case of success %0 is returned and @buf and @size are updated with
 * the amount of bytes read. If @tr is non-NULL and a trailing
 * character exists (size is non-zero after returning from this
 * function), @tr is updated with the trailing character.
 */
static int proc_get_long(char **buf, size_t *size,
                          unsigned long *val, bool *neg,
                          const char *perm_tr, unsigned perm_tr_len, char *tr)
{
        int len;
        char *p, tmp[TMPBUFLEN];

        if (!*size)
                return -EINVAL;

        len = *size;
        if (len > TMPBUFLEN - 1)
                len = TMPBUFLEN - 1;

        memcpy(tmp, *buf, len);

        tmp[len] = 0;
        p = tmp;
        if (*p == '-' && *size > 1) {
                *neg = true;
                p++;
        } else
                *neg = false;
        if (!isdigit(*p))
                return -EINVAL;

        *val = simple_strtoul(p, &p, 0);

        len = p - tmp;

        /* We don't know if the next char is whitespace thus we may accept
         * invalid integers (e.g. 1234...a) or two integers instead of one
         * (e.g. 123...1). So lets not allow such large numbers. */
        if (len == TMPBUFLEN - 1)
                return -EINVAL;

        if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
                return -EINVAL;

        if (tr && (len < *size))
                *tr = *p;

        *buf += len;
        *size -= len;

        return 0;
}

/**
 * proc_put_long - converts an integer to a decimal ASCII formatted string
 *
 * @buf: the user buffer
 * @size: the size of the user buffer
 * @val: the integer to be converted
 * @neg: sign of the number, %TRUE for negative
 *
 * In case of success %0 is returned and @buf and @size are updated with
 * the amount of bytes written.
 */
static int proc_put_long(void __user **buf, size_t *size, unsigned long val,
                          bool neg)
{
        int len;
        char tmp[TMPBUFLEN], *p = tmp;

        sprintf(p, "%s%lu", neg ? "-" : "", val);
        len = strlen(tmp);
        if (len > *size)
                len = *size;
        if (copy_to_user(*buf, tmp, len))
                return -EFAULT;
        *size -= len;
        *buf += len;
        return 0;
}
#undef TMPBUFLEN

static int proc_put_char(void __user **buf, size_t *size, char c)
{
        if (*size) {
                char __user **buffer = (char __user **)buf;
                if (put_user(c, *buffer))
                        return -EFAULT;
                (*size)--, (*buffer)++;
                *buf = *buffer;
        }
        return 0;
}

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

static const char proc_wspace_sep[] = { ' ', '\t', '\n' };

static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
                  int write, void __user *buffer,
                  size_t *lenp, loff_t *ppos,
                  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
                              int write, void *data),
                  void *data)
{
        int *i, vleft, first = 1, err = 0;
        unsigned long page = 0;
        size_t left;
        char *kbuf;
        
        if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
                *lenp = 0;
                return 0;
        }
        
        i = (int *) tbl_data;
        vleft = table->maxlen / sizeof(*i);
        left = *lenp;

        if (!conv)
                conv = do_proc_dointvec_conv;

        if (write) {
                if (left > PAGE_SIZE - 1)
                        left = PAGE_SIZE - 1;
                page = __get_free_page(GFP_TEMPORARY);
                kbuf = (char *) page;
                if (!kbuf)
                        return -ENOMEM;
                if (copy_from_user(kbuf, buffer, left)) {
                        err = -EFAULT;
                        goto free;
                }
                kbuf[left] = 0;
        }

        for (; left && vleft--; i++, first=0) {
                unsigned long lval;
                bool neg;

                if (write) {
                        left -= proc_skip_spaces(&kbuf);

                        if (!left)
                                break;
                        err = proc_get_long(&kbuf, &left, &lval, &neg,
                                             proc_wspace_sep,
                                             sizeof(proc_wspace_sep), NULL);
                        if (err)
                                break;
                        if (conv(&neg, &lval, i, 1, data)) {
                                err = -EINVAL;
                                break;
                        }
                } else {
                        if (conv(&neg, &lval, i, 0, data)) {
                                err = -EINVAL;
                                break;
                        }
                        if (!first)
                                err = proc_put_char(&buffer, &left, '\t');
                        if (err)
                                break;
                        err = proc_put_long(&buffer, &left, lval, neg);
                        if (err)
                                break;
                }
        }

        if (!write && !first && left && !err)
                err = proc_put_char(&buffer, &left, '\n');
        if (write && !err && left)
                left -= proc_skip_spaces(&kbuf);
free:
        if (write) {
                free_page(page);
                if (first)
                        return err ? : -EINVAL;
        }
        *lenp -= left;
        *ppos += *lenp;
        return err;
}

static int do_proc_dointvec(struct ctl_table *table, int write,
                  void __user *buffer, size_t *lenp, loff_t *ppos,
                  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
                              int write, void *data),
                  void *data)
{
        return __do_proc_dointvec(table->data, table, write,
                        buffer, lenp, ppos, conv, data);
}

/**
 * proc_dointvec - read a vector of integers
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * 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(struct ctl_table *table, int write,
                     void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,buffer,lenp,ppos,
                            NULL,NULL);
}

/*
 * Taint values can only be increased
 * This means we can safely use a temporary.
 */
static int proc_taint(struct ctl_table *table, int write,
                               void __user *buffer, size_t *lenp, loff_t *ppos)
{
        struct ctl_table t;
        unsigned long tmptaint = get_taint();
        int err;

        if (write && !capable(CAP_SYS_ADMIN))
                return -EPERM;

        t = *table;
        t.data = &tmptaint;
        err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
        if (err < 0)
                return err;

        if (write) {
                /*
                 * Poor man's atomic or. Not worth adding a primitive
                 * to everyone's atomic.h for this
                 */
                int i;
                for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
                        if ((tmptaint >> i) & 1)
                                add_taint(i);
                }
        }

        return err;
}

#ifdef CONFIG_PRINTK
static int proc_dmesg_restrict(struct ctl_table *table, int write,
                                void __user *buffer, size_t *lenp, loff_t *ppos)
{
        if (write && !capable(CAP_SYS_ADMIN))
                return -EPERM;

        return proc_dointvec_minmax(table, write, buffer, lenp, ppos);
}
#endif

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

static int do_proc_dointvec_minmax_conv(bool *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 = true;
                        *lvalp = (unsigned long)-val;
                } else {
                        *negp = false;
                        *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
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * 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(struct ctl_table *table, int write,
                  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, buffer, lenp, ppos,
                                do_proc_dointvec_minmax_conv, &param);
}

static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
                                     void __user *buffer,
                                     size_t *lenp, loff_t *ppos,
                                     unsigned long convmul,
                                     unsigned long convdiv)
{
        unsigned long *i, *min, *max;
        int vleft, first = 1, err = 0;
        unsigned long page = 0;
        size_t left;
        char *kbuf;

        if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
                *lenp = 0;
                return 0;
        }

        i = (unsigned long *) data;
        min = (unsigned long *) table->extra1;
        max = (unsigned long *) table->extra2;
        vleft = table->maxlen / sizeof(unsigned long);
        left = *lenp;

        if (write) {
                if (left > PAGE_SIZE - 1)
                        left = PAGE_SIZE - 1;
                page = __get_free_page(GFP_TEMPORARY);
                kbuf = (char *) page;
                if (!kbuf)
                        return -ENOMEM;
                if (copy_from_user(kbuf, buffer, left)) {
                        err = -EFAULT;
                        goto free;
                }
                kbuf[left] = 0;
        }

        for (; left && vleft--; i++, first = 0) {
                unsigned long val;

                if (write) {
                        bool neg;

                        left -= proc_skip_spaces(&kbuf);

                        err = proc_get_long(&kbuf, &left, &val, &neg,
                                             proc_wspace_sep,
                                             sizeof(proc_wspace_sep), NULL);
                        if (err)
                                break;
                        if (neg)
                                continue;
                        if ((min && val < *min) || (max && val > *max))
                                continue;
                        *i = val;
                } else {
                        val = convdiv * (*i) / convmul;
                        if (!first)
                                err = proc_put_char(&buffer, &left, '\t');
                        err = proc_put_long(&buffer, &left, val, false);
                        if (err)
                                break;
                }
        }

        if (!write && !first && left && !err)
                err = proc_put_char(&buffer, &left, '\n');
        if (write && !err)
                left -= proc_skip_spaces(&kbuf);
free:
        if (write) {
                free_page(page);
                if (first)
                        return err ? : -EINVAL;
        }
        *lenp -= left;
        *ppos += *lenp;
        return err;
}

static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
                                     void __user *buffer,
                                     size_t *lenp, loff_t *ppos,
                                     unsigned long convmul,
                                     unsigned long convdiv)
{
        return __do_proc_doulongvec_minmax(table->data, table, write,
                        buffer, lenp, ppos, convmul, convdiv);
}

/**
 * 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
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * 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(struct ctl_table *table, int write,
                           void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_doulongvec_minmax(table, write, 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
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * 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(struct ctl_table *table, int write,
                                      void __user *buffer,
                                      size_t *lenp, loff_t *ppos)
{
    return do_proc_doulongvec_minmax(table, write, buffer,
                                     lenp, ppos, HZ, 1000l);
}


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

static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
                                                int *valp,
                                                int write, void *data)
{
        if (write) {
                if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
                        return 1;
                *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
        } else {
                int val = *valp;
                unsigned long lval;
                if (val < 0) {
                        *negp = true;
                        lval = (unsigned long)-val;
                } else {
                        *negp = false;
                        lval = (unsigned long)val;
                }
                *lvalp = jiffies_to_clock_t(lval);
        }
        return 0;
}

static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
                                            int *valp,
                                            int write, void *data)
{
        if (write) {
                *valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
        } else {
                int val = *valp;
                unsigned long lval;
                if (val < 0) {
                        *negp = true;
                        lval = (unsigned long)-val;
                } else {
                        *negp = false;
                        lval = (unsigned long)val;
                }
                *lvalp = jiffies_to_msecs(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
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * 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(struct ctl_table *table, int write,
                          void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,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
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: pointer to the file position
 *
 * 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(struct ctl_table *table, int write,
                                 void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,buffer,lenp,ppos,
                            do_proc_dointvec_userhz_jiffies_conv,NULL);
}

/**
 * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 * @ppos: the current position in the file
 *
 * 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 1/1000 seconds, and 
 * are converted into jiffies.
 *
 * Returns 0 on success.
 */
int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
                             void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return do_proc_dointvec(table, write, buffer, lenp, ppos,
                                do_proc_dointvec_ms_jiffies_conv, NULL);
}

static int proc_do_cad_pid(struct ctl_table *table, int write,
                           void __user *buffer, size_t *lenp, loff_t *ppos)
{
        struct pid *new_pid;
        pid_t tmp;
        int r;

        tmp = pid_vnr(cad_pid);

        r = __do_proc_dointvec(&tmp, table, write, buffer,
                               lenp, ppos, NULL, NULL);
        if (r || !write)
                return r;

        new_pid = find_get_pid(tmp);
        if (!new_pid)
                return -ESRCH;

        put_pid(xchg(&cad_pid, new_pid));
        return 0;
}

/**
 * proc_do_large_bitmap - read/write from/to a large bitmap
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @ppos: file position
 *
 * The bitmap is stored at table->data and the bitmap length (in bits)
 * in table->maxlen.
 *
 * We use a range comma separated format (e.g. 1,3-4,10-10) so that
 * large bitmaps may be represented in a compact manner. Writing into
 * the file will clear the bitmap then update it with the given input.
 *
 * Returns 0 on success.
 */
int proc_do_large_bitmap(struct ctl_table *table, int write,
                         void __user *buffer, size_t *lenp, loff_t *ppos)
{
        int err = 0;
        bool first = 1;
        size_t left = *lenp;
        unsigned long bitmap_len = table->maxlen;
        unsigned long *bitmap = (unsigned long *) table->data;
        unsigned long *tmp_bitmap = NULL;
        char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;

        if (!bitmap_len || !left || (*ppos && !write)) {
                *lenp = 0;
                return 0;
        }

        if (write) {
                unsigned long page = 0;
                char *kbuf;

                if (left > PAGE_SIZE - 1)
                        left = PAGE_SIZE - 1;

                page = __get_free_page(GFP_TEMPORARY);
                kbuf = (char *) page;
                if (!kbuf)
                        return -ENOMEM;
                if (copy_from_user(kbuf, buffer, left)) {
                        free_page(page);
                        return -EFAULT;
                }
                kbuf[left] = 0;

                tmp_bitmap = kzalloc(BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long),
                                     GFP_KERNEL);
                if (!tmp_bitmap) {
                        free_page(page);
                        return -ENOMEM;
                }
                proc_skip_char(&kbuf, &left, '\n');
                while (!err && left) {
                        unsigned long val_a, val_b;
                        bool neg;

                        err = proc_get_long(&kbuf, &left, &val_a, &neg, tr_a,
                                             sizeof(tr_a), &c);
                        if (err)
                                break;
                        if (val_a >= bitmap_len || neg) {
                                err = -EINVAL;
                                break;
                        }

                        val_b = val_a;
                        if (left) {
                                kbuf++;
                                left--;
                        }

                        if (c == '-') {
                                err = proc_get_long(&kbuf, &left, &val_b,
                                                     &neg, tr_b, sizeof(tr_b),
                                                     &c);
                                if (err)
                                        break;
                                if (val_b >= bitmap_len || neg ||
                                    val_a > val_b) {
                                        err = -EINVAL;
                                        break;
                                }
                                if (left) {
                                        kbuf++;
                                        left--;
                                }
                        }

                        while (val_a <= val_b)
                                set_bit(val_a++, tmp_bitmap);

                        first = 0;
                        proc_skip_char(&kbuf, &left, '\n');
                }
                free_page(page);
        } else {
                unsigned long bit_a, bit_b = 0;

                while (left) {
                        bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
                        if (bit_a >= bitmap_len)
                                break;
                        bit_b = find_next_zero_bit(bitmap, bitmap_len,
                                                   bit_a + 1) - 1;

                        if (!first) {
                                err = proc_put_char(&buffer, &left, ',');
                                if (err)
                                        break;
                        }
                        err = proc_put_long(&buffer, &left, bit_a, false);
                        if (err)
                                break;
                        if (bit_a != bit_b) {
                                err = proc_put_char(&buffer, &left, '-');
                                if (err)
                                        break;
                                err = proc_put_long(&buffer, &left, bit_b, false);
                                if (err)
                                        break;
                        }

                        first = 0; bit_b++;
                }
                if (!err)
                        err = proc_put_char(&buffer, &left, '\n');
        }

        if (!err) {
                if (write) {
                        if (*ppos)
                                bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
                        else
                                memcpy(bitmap, tmp_bitmap,
                                        BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
                }
                kfree(tmp_bitmap);
                *lenp -= left;
                *ppos += *lenp;
                return 0;
        } else {
                kfree(tmp_bitmap);
                return err;
        }
}

#else /* CONFIG_PROC_SYSCTL */

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

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

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

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

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

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

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

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


#endif /* CONFIG_PROC_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_dointvec_ms_jiffies);
EXPORT_SYMBOL(proc_dostring);
EXPORT_SYMBOL(proc_doulongvec_minmax);
EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
EXPORT_SYMBOL(register_sysctl_table);
EXPORT_SYMBOL(register_sysctl_paths);
EXPORT_SYMBOL(unregister_sysctl_table);