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root/kernel/sysctl.c

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DEFINITIONS

This source file includes following definitions.
  1. use_table
  2. unuse_table
  3. start_unregistering
  4. sysctl_head_get
  5. sysctl_head_put
  6. sysctl_head_grab
  7. sysctl_head_finish
  8. lookup_header_set
  9. lookup_header_list
  10. __sysctl_head_next
  11. sysctl_head_next
  12. register_sysctl_root
  13. do_sysctl_strategy
  14. parse_table
  15. do_sysctl
  16. sys_sysctl
  17. test_perm
  18. sysctl_perm
  19. sysctl_set_parent
  20. sysctl_init
  21. is_branch_in
  22. try_attach
  23. __register_sysctl_paths
  24. register_sysctl_paths
  25. register_sysctl_table
  26. unregister_sysctl_table
  27. sysctl_is_seen
  28. setup_sysctl_set
  29. register_sysctl_table
  30. register_sysctl_paths
  31. unregister_sysctl_table
  32. setup_sysctl_set
  33. sysctl_head_put
  34. _proc_do_string
  35. proc_dostring
  36. do_proc_dointvec_conv
  37. __do_proc_dointvec
  38. do_proc_dointvec
  39. proc_dointvec
  40. do_proc_dointvec_bset_conv
  41. proc_dointvec_taint
  42. do_proc_dointvec_minmax_conv
  43. proc_dointvec_minmax
  44. __do_proc_doulongvec_minmax
  45. do_proc_doulongvec_minmax
  46. proc_doulongvec_minmax
  47. proc_doulongvec_ms_jiffies_minmax
  48. do_proc_dointvec_jiffies_conv
  49. do_proc_dointvec_userhz_jiffies_conv
  50. do_proc_dointvec_ms_jiffies_conv
  51. proc_dointvec_jiffies
  52. proc_dointvec_userhz_jiffies
  53. proc_dointvec_ms_jiffies
  54. proc_do_cad_pid
  55. proc_dostring
  56. proc_dointvec
  57. proc_dointvec_minmax
  58. proc_dointvec_jiffies
  59. proc_dointvec_userhz_jiffies
  60. proc_dointvec_ms_jiffies
  61. proc_doulongvec_minmax
  62. proc_doulongvec_ms_jiffies_minmax
  63. sysctl_data
  64. sysctl_string
  65. sysctl_intvec
  66. sysctl_jiffies
  67. sysctl_ms_jiffies
  68. sys_sysctl
  69. sysctl_data
  70. sysctl_string
  71. sysctl_intvec
  72. sysctl_jiffies
  73. sysctl_ms_jiffies
  74. deprecated_sysctl_warning

/*
 * 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/proc_fs.h>
#include <linux/security.h>
#include <linux/ctype.h>
#include <linux/utsname.h>
#include <linux/smp_lock.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/hugetlb.h>
#include <linux/initrd.h>
#include <linux/key.h>
#include <linux/times.h>
#include <linux/limits.h>
#include <linux/dcache.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 <asm/uaccess.h>
#include <asm/processor.h>

#ifdef CONFIG_X86
#include <asm/nmi.h>
#include <asm/stacktrace.h>
#include <asm/io.h>
#endif

static int deprecated_sysctl_warning(struct __sysctl_args *args);

#if defined(CONFIG_SYSCTL)

/* External variables not in a header file. */
extern int C_A_D;
extern int print_fatal_signals;
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern int sysctl_panic_on_oom;
extern int sysctl_oom_kill_allocating_task;
extern int sysctl_oom_dump_tasks;
extern int max_threads;
extern int core_uses_pid;
extern int suid_dumpable;
extern char core_pattern[];
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;
#ifdef CONFIG_RCU_TORTURE_TEST
extern int rcutorture_runnable;
#endif /* #ifdef CONFIG_RCU_TORTURE_TEST */

/* Constants used for minimum and  maximum */
#if defined(CONFIG_HIGHMEM) || defined(CONFIG_DETECT_SOFTLOCKUP)
static int one = 1;
#endif

#ifdef CONFIG_DETECT_SOFTLOCKUP
static int sixty = 60;
static int neg_one = -1;
#endif

#if defined(CONFIG_MMU) && defined(CONFIG_FILE_LOCKING)
static int two = 2;
#endif

static int zero;
static int one_hundred = 100;

/* 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_MODULES
extern char modprobe_path[];
#endif
#ifdef CONFIG_CHR_DEV_SG
extern int sg_big_buff;
#endif

#ifdef CONFIG_SPARC
#include <asm/system.h>
#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_BSD_PROCESS_ACCT
extern int acct_parm[];
#endif

#ifdef CONFIG_IA64
extern int no_unaligned_warning;
#endif

#ifdef CONFIG_RT_MUTEXES
extern int max_lock_depth;
#endif

#ifdef CONFIG_PROC_SYSCTL
static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos);
static int proc_dointvec_taint(struct ctl_table *table, int write, struct file *filp,
                               void __user *buffer, size_t *lenp, loff_t *ppos);
#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_INOTIFY_USER
extern struct ctl_table inotify_table[];
#endif

#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
int sysctl_legacy_va_layout;
#endif

extern int prove_locking;
extern int lock_stat;

/* The default sysctl tables: */

static struct ctl_table root_table[] = {
        {
                .ctl_name       = CTL_KERN,
                .procname       = "kernel",
                .mode           = 0555,
                .child          = kern_table,
        },
        {
                .ctl_name       = CTL_VM,
                .procname       = "vm",
                .mode           = 0555,
                .child          = vm_table,
        },
        {
                .ctl_name       = CTL_FS,
                .procname       = "fs",
                .mode           = 0555,
                .child          = fs_table,
        },
        {
                .ctl_name       = CTL_DEBUG,
                .procname       = "debug",
                .mode           = 0555,
                .child          = debug_table,
        },
        {
                .ctl_name       = CTL_DEV,
                .procname       = "dev",
                .mode           = 0555,
                .child          = dev_table,
        },
/*
 * NOTE: do not add new entries to this table unless you have read
 * Documentation/sysctl/ctl_unnumbered.txt
 */
        { .ctl_name = 0 }
};

#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 */
#endif

static struct ctl_table kern_table[] = {
#ifdef CONFIG_SCHED_DEBUG
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_min_granularity_ns",
                .data           = &sysctl_sched_min_granularity,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &sched_nr_latency_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_sched_granularity_ns,
                .extra2         = &max_sched_granularity_ns,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_latency_ns",
                .data           = &sysctl_sched_latency,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &sched_nr_latency_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_sched_granularity_ns,
                .extra2         = &max_sched_granularity_ns,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_wakeup_granularity_ns",
                .data           = &sysctl_sched_wakeup_granularity,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_wakeup_granularity_ns,
                .extra2         = &max_wakeup_granularity_ns,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_shares_ratelimit",
                .data           = &sysctl_sched_shares_ratelimit,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_child_runs_first",
                .data           = &sysctl_sched_child_runs_first,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_features",
                .data           = &sysctl_sched_features,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_migration_cost",
                .data           = &sysctl_sched_migration_cost,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_nr_migrate",
                .data           = &sysctl_sched_nr_migrate,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_rt_period_us",
                .data           = &sysctl_sched_rt_period,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &sched_rt_handler,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_rt_runtime_us",
                .data           = &sysctl_sched_rt_runtime,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &sched_rt_handler,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "sched_compat_yield",
                .data           = &sysctl_sched_compat_yield,
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#ifdef CONFIG_PROVE_LOCKING
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "prove_locking",
                .data           = &prove_locking,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_LOCK_STAT
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "lock_stat",
                .data           = &lock_stat,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_PANIC,
                .procname       = "panic",
                .data           = &panic_timeout,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_CORE_USES_PID,
                .procname       = "core_uses_pid",
                .data           = &core_uses_pid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_CORE_PATTERN,
                .procname       = "core_pattern",
                .data           = core_pattern,
                .maxlen         = CORENAME_MAX_SIZE,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
#ifdef CONFIG_PROC_SYSCTL
        {
                .procname       = "tainted",
                .data           = &tainted,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_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
        {
                .ctl_name       = KERN_REALROOTDEV,
                .procname       = "real-root-dev",
                .data           = &real_root_dev,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "print-fatal-signals",
                .data           = &print_fatal_signals,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#ifdef CONFIG_SPARC
        {
                .ctl_name       = KERN_SPARC_REBOOT,
                .procname       = "reboot-cmd",
                .data           = reboot_command,
                .maxlen         = 256,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
        {
                .ctl_name       = KERN_SPARC_STOP_A,
                .procname       = "stop-a",
                .data           = &stop_a_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_SPARC_SCONS_PWROFF,
                .procname       = "scons-poweroff",
                .data           = &scons_pwroff,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef __hppa__
        {
                .ctl_name       = KERN_HPPA_PWRSW,
                .procname       = "soft-power",
                .data           = &pwrsw_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_HPPA_UNALIGNED,
                .procname       = "unaligned-trap",
                .data           = &unaligned_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_CTLALTDEL,
                .procname       = "ctrl-alt-del",
                .data           = &C_A_D,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#ifdef CONFIG_FTRACE
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "ftrace_enabled",
                .data           = &ftrace_enabled,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &ftrace_enable_sysctl,
        },
#endif
#ifdef CONFIG_MODULES
        {
                .ctl_name       = KERN_MODPROBE,
                .procname       = "modprobe",
                .data           = &modprobe_path,
                .maxlen         = KMOD_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
#endif
#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
        {
                .ctl_name       = KERN_HOTPLUG,
                .procname       = "hotplug",
                .data           = &uevent_helper,
                .maxlen         = UEVENT_HELPER_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
#endif
#ifdef CONFIG_CHR_DEV_SG
        {
                .ctl_name       = KERN_SG_BIG_BUFF,
                .procname       = "sg-big-buff",
                .data           = &sg_big_buff,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
        {
                .ctl_name       = KERN_ACCT,
                .procname       = "acct",
                .data           = &acct_parm,
                .maxlen         = 3*sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_MAGIC_SYSRQ
        {
                .ctl_name       = KERN_SYSRQ,
                .procname       = "sysrq",
                .data           = &__sysrq_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_PROC_SYSCTL
        {
                .procname       = "cad_pid",
                .data           = NULL,
                .maxlen         = sizeof (int),
                .mode           = 0600,
                .proc_handler   = &proc_do_cad_pid,
        },
#endif
        {
                .ctl_name       = KERN_MAX_THREADS,
                .procname       = "threads-max",
                .data           = &max_threads,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_RANDOM,
                .procname       = "random",
                .mode           = 0555,
                .child          = random_table,
        },
        {
                .ctl_name       = KERN_OVERFLOWUID,
                .procname       = "overflowuid",
                .data           = &overflowuid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .ctl_name       = KERN_OVERFLOWGID,
                .procname       = "overflowgid",
                .data           = &overflowgid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
#ifdef CONFIG_S390
#ifdef CONFIG_MATHEMU
        {
                .ctl_name       = KERN_IEEE_EMULATION_WARNINGS,
                .procname       = "ieee_emulation_warnings",
                .data           = &sysctl_ieee_emulation_warnings,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_S390_USER_DEBUG_LOGGING,
                .procname       = "userprocess_debug",
                .data           = &sysctl_userprocess_debug,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_PIDMAX,
                .procname       = "pid_max",
                .data           = &pid_max,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = sysctl_intvec,
                .extra1         = &pid_max_min,
                .extra2         = &pid_max_max,
        },
        {
                .ctl_name       = KERN_PANIC_ON_OOPS,
                .procname       = "panic_on_oops",
                .data           = &panic_on_oops,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#if defined CONFIG_PRINTK
        {
                .ctl_name       = KERN_PRINTK,
                .procname       = "printk",
                .data           = &console_loglevel,
                .maxlen         = 4*sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_PRINTK_RATELIMIT,
                .procname       = "printk_ratelimit",
                .data           = &printk_ratelimit_state.interval,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_jiffies,
                .strategy       = &sysctl_jiffies,
        },
        {
                .ctl_name       = KERN_PRINTK_RATELIMIT_BURST,
                .procname       = "printk_ratelimit_burst",
                .data           = &printk_ratelimit_state.burst,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = KERN_NGROUPS_MAX,
                .procname       = "ngroups_max",
                .data           = &ngroups_max,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
        {
                .ctl_name       = KERN_UNKNOWN_NMI_PANIC,
                .procname       = "unknown_nmi_panic",
                .data           = &unknown_nmi_panic,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .procname       = "nmi_watchdog",
                .data           = &nmi_watchdog_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_nmi_enabled,
        },
#endif
#if defined(CONFIG_X86)
        {
                .ctl_name       = KERN_PANIC_ON_NMI,
                .procname       = "panic_on_unrecovered_nmi",
                .data           = &panic_on_unrecovered_nmi,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = KERN_BOOTLOADER_TYPE,
                .procname       = "bootloader_type",
                .data           = &bootloader_type,
                .maxlen         = sizeof (int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "kstack_depth_to_print",
                .data           = &kstack_depth_to_print,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "io_delay_type",
                .data           = &io_delay_type,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#if defined(CONFIG_MMU)
        {
                .ctl_name       = KERN_RANDOMIZE,
                .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)
        {
                .ctl_name       = KERN_SPIN_RETRY,
                .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
        {
                .ctl_name       = KERN_IA64_UNALIGNED,
                .procname       = "ignore-unaligned-usertrap",
                .data           = &no_unaligned_warning,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_DETECT_SOFTLOCKUP
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "softlockup_panic",
                .data           = &softlockup_panic,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "softlockup_thresh",
                .data           = &softlockup_thresh,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &neg_one,
                .extra2         = &sixty,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "hung_task_check_count",
                .data           = &sysctl_hung_task_check_count,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
                .strategy       = &sysctl_intvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "hung_task_timeout_secs",
                .data           = &sysctl_hung_task_timeout_secs,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
                .strategy       = &sysctl_intvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "hung_task_warnings",
                .data           = &sysctl_hung_task_warnings,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
                .strategy       = &sysctl_intvec,
        },
#endif
#ifdef CONFIG_COMPAT
        {
                .ctl_name       = KERN_COMPAT_LOG,
                .procname       = "compat-log",
                .data           = &compat_log,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_RT_MUTEXES
        {
                .ctl_name       = KERN_MAX_LOCK_DEPTH,
                .procname       = "max_lock_depth",
                .data           = &max_lock_depth,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "poweroff_cmd",
                .data           = &poweroff_cmd,
                .maxlen         = POWEROFF_CMD_PATH_LEN,
                .mode           = 0644,
                .proc_handler   = &proc_dostring,
                .strategy       = &sysctl_string,
        },
#ifdef CONFIG_KEYS
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "keys",
                .mode           = 0555,
                .child          = key_sysctls,
        },
#endif
#ifdef CONFIG_RCU_TORTURE_TEST
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "rcutorture_runnable",
                .data           = &rcutorture_runnable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
/*
 * NOTE: do not add new entries to this table unless you have read
 * Documentation/sysctl/ctl_unnumbered.txt
 */
        { .ctl_name = 0 }
};

static struct ctl_table vm_table[] = {
        {
                .ctl_name       = VM_OVERCOMMIT_MEMORY,
                .procname       = "overcommit_memory",
                .data           = &sysctl_overcommit_memory,
                .maxlen         = sizeof(sysctl_overcommit_memory),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_PANIC_ON_OOM,
                .procname       = "panic_on_oom",
                .data           = &sysctl_panic_on_oom,
                .maxlen         = sizeof(sysctl_panic_on_oom),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "oom_kill_allocating_task",
                .data           = &sysctl_oom_kill_allocating_task,
                .maxlen         = sizeof(sysctl_oom_kill_allocating_task),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "oom_dump_tasks",
                .data           = &sysctl_oom_dump_tasks,
                .maxlen         = sizeof(sysctl_oom_dump_tasks),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_OVERCOMMIT_RATIO,
                .procname       = "overcommit_ratio",
                .data           = &sysctl_overcommit_ratio,
                .maxlen         = sizeof(sysctl_overcommit_ratio),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_PAGE_CLUSTER,
                .procname       = "page-cluster", 
                .data           = &page_cluster,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_DIRTY_BACKGROUND,
                .procname       = "dirty_background_ratio",
                .data           = &dirty_background_ratio,
                .maxlen         = sizeof(dirty_background_ratio),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .ctl_name       = VM_DIRTY_RATIO,
                .procname       = "dirty_ratio",
                .data           = &vm_dirty_ratio,
                .maxlen         = sizeof(vm_dirty_ratio),
                .mode           = 0644,
                .proc_handler   = &dirty_ratio_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .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_userhz_jiffies,
        },
        {
                .ctl_name       = VM_NR_PDFLUSH_THREADS,
                .procname       = "nr_pdflush_threads",
                .data           = &nr_pdflush_threads,
                .maxlen         = sizeof nr_pdflush_threads,
                .mode           = 0444 /* read-only*/,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = VM_SWAPPINESS,
                .procname       = "swappiness",
                .data           = &vm_swappiness,
                .maxlen         = sizeof(vm_swappiness),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
#ifdef CONFIG_HUGETLB_PAGE
         {
                .procname       = "nr_hugepages",
                .data           = NULL,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &hugetlb_sysctl_handler,
                .extra1         = (void *)&hugetlb_zero,
                .extra2         = (void *)&hugetlb_infinity,
         },
         {
                .ctl_name       = VM_HUGETLB_GROUP,
                .procname       = "hugetlb_shm_group",
                .data           = &sysctl_hugetlb_shm_group,
                .maxlen         = sizeof(gid_t),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
         },
         {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "hugepages_treat_as_movable",
                .data           = &hugepages_treat_as_movable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &hugetlb_treat_movable_handler,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .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
        {
                .ctl_name       = VM_LOWMEM_RESERVE_RATIO,
                .procname       = "lowmem_reserve_ratio",
                .data           = &sysctl_lowmem_reserve_ratio,
                .maxlen         = sizeof(sysctl_lowmem_reserve_ratio),
                .mode           = 0644,
                .proc_handler   = &lowmem_reserve_ratio_sysctl_handler,
                .strategy       = &sysctl_intvec,
        },
        {
                .ctl_name       = VM_DROP_PAGECACHE,
                .procname       = "drop_caches",
                .data           = &sysctl_drop_caches,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = drop_caches_sysctl_handler,
                .strategy       = &sysctl_intvec,
        },
        {
                .ctl_name       = VM_MIN_FREE_KBYTES,
                .procname       = "min_free_kbytes",
                .data           = &min_free_kbytes,
                .maxlen         = sizeof(min_free_kbytes),
                .mode           = 0644,
                .proc_handler   = &min_free_kbytes_sysctl_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_PERCPU_PAGELIST_FRACTION,
                .procname       = "percpu_pagelist_fraction",
                .data           = &percpu_pagelist_fraction,
                .maxlen         = sizeof(percpu_pagelist_fraction),
                .mode           = 0644,
                .proc_handler   = &percpu_pagelist_fraction_sysctl_handler,
                .strategy       = &sysctl_intvec,
                .extra1         = &min_percpu_pagelist_fract,
        },
#ifdef CONFIG_MMU
        {
                .ctl_name       = VM_MAX_MAP_COUNT,
                .procname       = "max_map_count",
                .data           = &sysctl_max_map_count,
                .maxlen         = sizeof(sysctl_max_map_count),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec
        },
#endif
        {
                .ctl_name       = VM_LAPTOP_MODE,
                .procname       = "laptop_mode",
                .data           = &laptop_mode,
                .maxlen         = sizeof(laptop_mode),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_jiffies,
                .strategy       = &sysctl_jiffies,
        },
        {
                .ctl_name       = VM_BLOCK_DUMP,
                .procname       = "block_dump",
                .data           = &block_dump,
                .maxlen         = sizeof(block_dump),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_VFS_CACHE_PRESSURE,
                .procname       = "vfs_cache_pressure",
                .data           = &sysctl_vfs_cache_pressure,
                .maxlen         = sizeof(sysctl_vfs_cache_pressure),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
        {
                .ctl_name       = VM_LEGACY_VA_LAYOUT,
                .procname       = "legacy_va_layout",
                .data           = &sysctl_legacy_va_layout,
                .maxlen         = sizeof(sysctl_legacy_va_layout),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
#endif
#ifdef CONFIG_NUMA
        {
                .ctl_name       = VM_ZONE_RECLAIM_MODE,
                .procname       = "zone_reclaim_mode",
                .data           = &zone_reclaim_mode,
                .maxlen         = sizeof(zone_reclaim_mode),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
        {
                .ctl_name       = VM_MIN_UNMAPPED,
                .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,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
        {
                .ctl_name       = VM_MIN_SLAB,
                .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,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one_hundred,
        },
#endif
#ifdef CONFIG_SMP
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "stat_interval",
                .data           = &sysctl_stat_interval,
                .maxlen         = sizeof(sysctl_stat_interval),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_jiffies,
                .strategy       = &sysctl_jiffies,
        },
#endif
#ifdef CONFIG_SECURITY
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "mmap_min_addr",
                .data           = &mmap_min_addr,
                .maxlen         = sizeof(unsigned long),
                .mode           = 0644,
                .proc_handler   = &proc_doulongvec_minmax,
        },
#endif
#ifdef CONFIG_NUMA
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "numa_zonelist_order",
                .data           = &numa_zonelist_order,
                .maxlen         = NUMA_ZONELIST_ORDER_LEN,
                .mode           = 0644,
                .proc_handler   = &numa_zonelist_order_handler,
                .strategy       = &sysctl_string,
        },
#endif
#if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
   (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
        {
                .ctl_name       = VM_VDSO_ENABLED,
                .procname       = "vdso_enabled",
                .data           = &vdso_enabled,
                .maxlen         = sizeof(vdso_enabled),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
        },
#endif
#ifdef CONFIG_HIGHMEM
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "highmem_is_dirtyable",
                .data           = &vm_highmem_is_dirtyable,
                .maxlen         = sizeof(vm_highmem_is_dirtyable),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &one,
        },
#endif
/*
 * NOTE: do not add new entries to this table unless you have read
 * Documentation/sysctl/ctl_unnumbered.txt
 */
        { .ctl_name = 0 }
};

#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
static struct ctl_table binfmt_misc_table[] = {
        { .ctl_name = 0 }
};
#endif

static struct ctl_table fs_table[] = {
        {
                .ctl_name       = FS_NRINODE,
                .procname       = "inode-nr",
                .data           = &inodes_stat,
                .maxlen         = 2*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_STATINODE,
                .procname       = "inode-state",
                .data           = &inodes_stat,
                .maxlen         = 7*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .procname       = "file-nr",
                .data           = &files_stat,
                .maxlen         = 3*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_nr_files,
        },
        {
                .ctl_name       = FS_MAXFILE,
                .procname       = "file-max",
                .data           = &files_stat.max_files,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = CTL_UNNUMBERED,
                .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,
        },
        {
                .ctl_name       = FS_DENTRY,
                .procname       = "dentry-state",
                .data           = &dentry_stat,
                .maxlen         = 6*sizeof(int),
                .mode           = 0444,
                .proc_handler   = &proc_dointvec,
        },
        {
                .ctl_name       = FS_OVERFLOWUID,
                .procname       = "overflowuid",
                .data           = &fs_overflowuid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
        {
                .ctl_name       = FS_OVERFLOWGID,
                .procname       = "overflowgid",
                .data           = &fs_overflowgid,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &minolduid,
                .extra2         = &maxolduid,
        },
#ifdef CONFIG_FILE_LOCKING
        {
                .ctl_name       = FS_LEASES,
                .procname       = "leases-enable",
                .data           = &leases_enable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#endif
#ifdef CONFIG_DNOTIFY
        {
                .ctl_name       = FS_DIR_NOTIFY,
                .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
        {
                .ctl_name       = FS_LEASE_TIME,
                .procname       = "lease-break-time",
                .data           = &lease_break_time,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec_minmax,
                .strategy       = &sysctl_intvec,
                .extra1         = &zero,
                .extra2         = &two,
        },
#endif
        {
                .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,
        },
#ifdef CONFIG_INOTIFY_USER
        {
                .ctl_name       = FS_INOTIFY,
                .procname       = "inotify",
                .mode           = 0555,
                .child          = inotify_table,
        },
#endif  
#endif
        {
                .ctl_name       = KERN_SETUID_DUMPABLE,
                .procname       = "suid_dumpable",
                .data           = &suid_dumpable,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = &proc_dointvec,
        },
#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "binfmt_misc",
                .mode           = 0555,
                .child          = binfmt_misc_table,
        },
#endif
/*
 * NOTE: do not add new entries to this table unless you have read
 * Documentation/sysctl/ctl_unnumbered.txt
 */
        { .ctl_name = 0 }
};

static struct ctl_table debug_table[] = {
#if defined(CONFIG_X86) || defined(CONFIG_PPC)
        {
                .ctl_name       = CTL_UNNUMBERED,
                .procname       = "exception-trace",
                .data           = &show_unhandled_signals,
                .maxlen         = sizeof(int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec
        },
#endif
        { .ctl_name = 0 }
};

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

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);
}

void sysctl_head_put(struct ctl_table_header *head)
{
        spin_lock(&sysctl_lock);
        if (!--head->count)
                kfree(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);
}

#ifdef CONFIG_SYSCTL_SYSCALL
/* Perform the actual read/write of a sysctl table entry. */
static int do_sysctl_strategy(struct ctl_table_root *root,
                        struct ctl_table *table,
                        int __user *name, int nlen,
                        void __user *oldval, size_t __user *oldlenp,
                        void __user *newval, size_t newlen)
{
        int op = 0, rc;

        if (oldval)
                op |= MAY_READ;
        if (newval)
                op |= MAY_WRITE;
        if (sysctl_perm(root, table, op))
                return -EPERM;

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

        /* If there is no strategy routine, or if the strategy returns
         * zero, proceed with automatic r/w */
        if (table->data && table->maxlen) {
                rc = sysctl_data(table, name, nlen, oldval, oldlenp,
                                 newval, newlen);
                if (rc < 0)
                        return rc;
        }
        return 0;
}

static int parse_table(int __user *name, int nlen,
                       void __user *oldval, size_t __user *oldlenp,
                       void __user *newval, size_t newlen,
                       struct ctl_table_root *root,
                       struct ctl_table *table)
{
        int n;
repeat:
        if (!nlen)
                return -ENOTDIR;
        if (get_user(n, name))
                return -EFAULT;
        for ( ; table->ctl_name || table->procname; table++) {
                if (!table->ctl_name)
                        continue;
                if (n == table->ctl_name) {
                        int error;
                        if (table->child) {
                                if (sysctl_perm(root, table, MAY_EXEC))
                                        return -EPERM;
                                name++;
                                nlen--;
                                table = table->child;
                                goto repeat;
                        }
                        error = do_sysctl_strategy(root, table, name, nlen,
                                                   oldval, oldlenp,
                                                   newval, newlen);
                        return error;
                }
        }
        return -ENOTDIR;
}

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

        if (nlen <= 0 || nlen >= CTL_MAXNAME)
                return -ENOTDIR;
        if (oldval) {
                int old_len;
                if (!oldlenp || get_user(old_len, oldlenp))
                        return -EFAULT;
        }

        for (head = sysctl_head_next(NULL); head;
                        head = sysctl_head_next(head)) {
                error = parse_table(name, nlen, oldval, oldlenp, 
                                        newval, newlen,
                                        head->root, head->ctl_table);
                if (error != -ENOTDIR) {
                        sysctl_head_finish(head);
                        break;
                }
        }
        return error;
}

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

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

        error = deprecated_sysctl_warning(&tmp);
        if (error)
                goto out;

        lock_kernel();
        error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
                          tmp.newval, tmp.newlen);
        unlock_kernel();
out:
        return error;
}
#endif /* CONFIG_SYSCTL_SYSCALL */

/*
 * 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 error;
        int mode;

        error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
        if (error)
                return error;

        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->ctl_name || 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
        {
                int err;
                err = 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 || branch[1].ctl_name)
                return NULL;

        /* table should contain subdirectory with the same name */
        for (p = table; p->procname || p->ctl_name; 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:
 *
 * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
 *            must be unique within that level of sysctl
 *
 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
 *            enter a sysctl file
 *
 * data - a pointer to data for use by proc_handler
 *
 * maxlen - the maximum size in bytes of the data
 *
 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
 *
 * child - a pointer to the child sysctl table if this entry is a directory, or
 *         %NULL.
 *
 * proc_handler - the text handler routine (described below)
 *
 * strategy - the strategy routine (described below)
 *
 * de - for internal use by the sysctl routines
 *
 * extra1, extra2 - extra pointers usable by the proc handler routines
 *
 * Leaf nodes in the sysctl tree will be represented by a single file
 * under /proc; non-leaf nodes will be represented by directories.
 *
 * sysctl(2) can automatically manage read and write requests through
 * the sysctl table.  The data and maxlen fields of the ctl_table
 * struct enable minimal validation of the values being written to be
 * performed, and the mode field allows minimal authentication.
 *
 * More sophisticated management can be enabled by the provision of a
 * strategy routine with the table entry.  This will be called before
 * any automatic read or write of the data is performed.
 *
 * The strategy routine may return
 *
 * < 0 - Error occurred (error is passed to user process)
 *
 * 0   - OK - proceed with automatic read or write.
 *
 * > 0 - OK - read or write has been done by the strategy routine, so
 *       return immediately.
 *
 * There must be a proc_handler routine for any terminal nodes
 * mirrored under /proc/sys (non-terminals are handled by a built-in
 * directory handler).  Several default handlers are available to
 * cover common cases -
 *
 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 
 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
 *
 * It is the handler's job to read the input buffer from user memory
 * and process it. The handler should return 0 on success.
 *
 * This routine returns %NULL on a failure to register, and a pointer
 * to the table header on success.
 */
struct ctl_table_header *__register_sysctl_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].ctl_name || 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 (ctl_name == 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->ctl_name = path->ctl_name;
                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);
                kfree(header->parent);
        }
        if (!--header->count)
                kfree(header);
        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,
                           struct file *filp, 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
 * @filp: the file structure
 * @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, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return _proc_do_string(table->data, table->maxlen, write, filp,
                               buffer, lenp, ppos);
}


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

static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
                  int write, struct file *filp, void __user *buffer,
                  size_t *lenp, loff_t *ppos,
                  int (*conv)(int *negp, unsigned long *lvalp, int *valp,
                              int write, void *data),
                  void *data)
{
#define TMPBUFLEN 21
        int *i, vleft, first=1, neg, val;
        unsigned long lval;
        size_t left, len;
        
        char buf[TMPBUFLEN], *p;
        char __user *s = buffer;
        
        if (!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;

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

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

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

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

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

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

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

#define OP_SET  0
#define OP_AND  1
#define OP_OR   2

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

/*
 *      Taint values can only be increased
 */
static int proc_dointvec_taint(struct ctl_table *table, int write, struct file *filp,
                               void __user *buffer, size_t *lenp, loff_t *ppos)
{
        int op;

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

        op = OP_OR;
        return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                                do_proc_dointvec_bset_conv,&op);
}

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

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

/**
 * proc_dointvec_minmax - read a vector of integers with min/max values
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @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, struct file *filp,
                  void __user *buffer, size_t *lenp, loff_t *ppos)
{
        struct do_proc_dointvec_minmax_conv_param param = {
                .min = (int *) table->extra1,
                .max = (int *) table->extra2,
        };
        return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
                                do_proc_dointvec_minmax_conv, &param);
}

static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
                                     struct file *filp,
                                     void __user *buffer,
                                     size_t *lenp, loff_t *ppos,
                                     unsigned long convmul,
                                     unsigned long convdiv)
{
#define TMPBUFLEN 21
        unsigned long *i, *min, *max, val;
        int vleft, first=1, neg;
        size_t len, left;
        char buf[TMPBUFLEN], *p;
        char __user *s = buffer;
        
        if (!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;
        
        for (; left && vleft--; i++, min++, max++, first=0) {
                if (write) {
                        while (left) {
                                char c;
                                if (get_user(c, s))
                                        return -EFAULT;
                                if (!isspace(c))
                                        break;
                                left--;
                                s++;
                        }
                        if (!left)
                                break;
                        neg = 0;
                        len = left;
                        if (len > TMPBUFLEN-1)
                                len = TMPBUFLEN-1;
                        if (copy_from_user(buf, s, len))
                                return -EFAULT;
                        buf[len] = 0;
                        p = buf;
                        if (*p == '-' && left > 1) {
                                neg = 1;
                                p++;
                        }
                        if (*p < '0' || *p > '9')
                                break;
                        val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
                        len = p-buf;
                        if ((len < left) && *p && !isspace(*p))
                                break;
                        if (neg)
                                val = -val;
                        s += len;
                        left -= len;

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

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

static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
                                     struct file *filp,
                                     void __user *buffer,
                                     size_t *lenp, loff_t *ppos,
                                     unsigned long convmul,
                                     unsigned long convdiv)
{
        return __do_proc_doulongvec_minmax(table->data, table, write,
                        filp, 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
 * @filp: the file structure
 * @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, struct file *filp,
                           void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos, 1l, 1l);
}

/**
 * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @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,
                                      struct file *filp,
                                      void __user *buffer,
                                      size_t *lenp, loff_t *ppos)
{
    return do_proc_doulongvec_minmax(table, write, filp, buffer,
                                     lenp, ppos, HZ, 1000l);
}


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

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

static int do_proc_dointvec_ms_jiffies_conv(int *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 = -1;
                        lval = (unsigned long)-val;
                } else {
                        *negp = 0;
                        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
 * @filp: the file structure
 * @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, struct file *filp,
                          void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                            do_proc_dointvec_jiffies_conv,NULL);
}

/**
 * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
 * @table: the sysctl table
 * @write: %TRUE if this is a write to the sysctl file
 * @filp: the file structure
 * @buffer: the user buffer
 * @lenp: the size of the user buffer
 * @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, struct file *filp,
                                 void __user *buffer, size_t *lenp, loff_t *ppos)
{
    return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
                            do_proc_dointvec_userhz_jiffies_conv,NULL);
}

/**
 * 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
 * @filp: the file structure
 * @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, struct file *filp,
                             void __user *buffer, size_t *lenp, loff_t *ppos)
{
        return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
                                do_proc_dointvec_ms_jiffies_conv, NULL);
}

static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp,
                           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, filp, 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;
}

#else /* CONFIG_PROC_FS */

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

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

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

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

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

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

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

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


#endif /* CONFIG_PROC_FS */


#ifdef CONFIG_SYSCTL_SYSCALL
/*
 * General sysctl support routines 
 */

/* The generic sysctl data routine (used if no strategy routine supplied) */
int sysctl_data(struct ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen)
{
        size_t len;

        /* Get out of I don't have a variable */
        if (!table->data || !table->maxlen)
                return -ENOTDIR;

        if (oldval && oldlenp) {
                if (get_user(len, oldlenp))
                        return -EFAULT;
                if (len) {
                        if (len > table->maxlen)
                                len = table->maxlen;
                        if (copy_to_user(oldval, table->data, len))
                                return -EFAULT;
                        if (put_user(len, oldlenp))
                                return -EFAULT;
                }
        }

        if (newval && newlen) {
                if (newlen > table->maxlen)
                        newlen = table->maxlen;

                if (copy_from_user(table->data, newval, newlen))
                        return -EFAULT;
        }
        return 1;
}

/* The generic string strategy routine: */
int sysctl_string(struct ctl_table *table, int __user *name, int nlen,
                  void __user *oldval, size_t __user *oldlenp,
                  void __user *newval, size_t newlen)
{
        if (!table->data || !table->maxlen) 
                return -ENOTDIR;
        
        if (oldval && oldlenp) {
                size_t bufsize;
                if (get_user(bufsize, oldlenp))
                        return -EFAULT;
                if (bufsize) {
                        size_t len = strlen(table->data), copied;

                        /* This shouldn't trigger for a well-formed sysctl */
                        if (len > table->maxlen)
                                len = table->maxlen;

                        /* Copy up to a max of bufsize-1 bytes of the string */
                        copied = (len >= bufsize) ? bufsize - 1 : len;

                        if (copy_to_user(oldval, table->data, copied) ||
                            put_user(0, (char __user *)(oldval + copied)))
                                return -EFAULT;
                        if (put_user(len, oldlenp))
                                return -EFAULT;
                }
        }
        if (newval && newlen) {
                size_t len = newlen;
                if (len > table->maxlen)
                        len = table->maxlen;
                if(copy_from_user(table->data, newval, len))
                        return -EFAULT;
                if (len == table->maxlen)
                        len--;
                ((char *) table->data)[len] = 0;
        }
        return 1;
}

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

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

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

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

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

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

/* Strategy function to convert jiffies to seconds */ 
int sysctl_jiffies(struct ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen)
{
        if (oldval && oldlenp) {
                size_t olen;

                if (get_user(olen, oldlenp))
                        return -EFAULT;
                if (olen) {
                        int val;

                        if (olen < sizeof(int))
                                return -EINVAL;

                        val = *(int *)(table->data) / HZ;
                        if (put_user(val, (int __user *)oldval))
                                return -EFAULT;
                        if (put_user(sizeof(int), oldlenp))
                                return -EFAULT;
                }
        }
        if (newval && newlen) { 
                int new;
                if (newlen != sizeof(int))
                        return -EINVAL; 
                if (get_user(new, (int __user *)newval))
                        return -EFAULT;
                *(int *)(table->data) = new*HZ; 
        }
        return 1;
}

/* Strategy function to convert jiffies to seconds */ 
int sysctl_ms_jiffies(struct ctl_table *table, int __user *name, int nlen,
                void __user *oldval, size_t __user *oldlenp,
                void __user *newval, size_t newlen)
{
        if (oldval && oldlenp) {
                size_t olen;

                if (get_user(olen, oldlenp))
                        return -EFAULT;
                if (olen) {
                        int val;

                        if (olen < sizeof(int))
                                return -EINVAL;

                        val = jiffies_to_msecs(*(int *)(table->data));
                        if (put_user(val, (int __user *)oldval))
                                return -EFAULT;
                        if (put_user(sizeof(int), oldlenp))
                                return -EFAULT;
                }
        }
        if (newval && newlen) { 
                int new;
                if (newlen != sizeof(int))
                        return -EINVAL; 
                if (get_user(new, (int __user *)newval))
                        return -EFAULT;
                *(int *)(table->data) = msecs_to_jiffies(new);
        }
        return 1;
}



#else /* CONFIG_SYSCTL_SYSCALL */


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

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

        error = deprecated_sysctl_warning(&tmp);

        /* If no error reading the parameters then just -ENOSYS ... */
        if (!error)
                error = -ENOSYS;

        return error;
}

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

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

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

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

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

#endif /* CONFIG_SYSCTL_SYSCALL */

static int deprecated_sysctl_warning(struct __sysctl_args *args)
{
        static int msg_count;
        int name[CTL_MAXNAME];
        int i;

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

        /* Read in the sysctl name for better debug message logging */
        for (i = 0; i < args->nlen; i++)
                if (get_user(name[i], args->name + i))
                        return -EFAULT;

        /* Ignore accesses to kernel.version */
        if ((args->nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
                return 0;

        if (msg_count < 5) {
                msg_count++;
                printk(KERN_INFO
                        "warning: process `%s' used the deprecated sysctl "
                        "system call with ", current->comm);
                for (i = 0; i < args->nlen; i++)
                        printk("%d.", name[i]);
                printk("\n");
        }
        return 0;
}

/*
 * 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(sysctl_intvec);
EXPORT_SYMBOL(sysctl_jiffies);
EXPORT_SYMBOL(sysctl_ms_jiffies);
EXPORT_SYMBOL(sysctl_string);
EXPORT_SYMBOL(sysctl_data);
EXPORT_SYMBOL(unregister_sysctl_table);

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