Root/kernel/sysctl.c

1/*
2 * sysctl.c: General linux system control interface
3 *
4 * Begun 24 March 1995, Stephen Tweedie
5 * Added /proc support, Dec 1995
6 * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
7 * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
8 * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
9 * Dynamic registration fixes, Stephen Tweedie.
10 * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
11 * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
12 * Horn.
13 * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
14 * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
15 * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
16 * Wendling.
17 * The list_for_each() macro wasn't appropriate for the sysctl loop.
18 * Removed it and replaced it with older style, 03/23/00, Bill Wendling
19 */
20
21#include <linux/module.h>
22#include <linux/mm.h>
23#include <linux/swap.h>
24#include <linux/slab.h>
25#include <linux/sysctl.h>
26#include <linux/signal.h>
27#include <linux/proc_fs.h>
28#include <linux/security.h>
29#include <linux/ctype.h>
30#include <linux/kmemcheck.h>
31#include <linux/fs.h>
32#include <linux/init.h>
33#include <linux/kernel.h>
34#include <linux/kobject.h>
35#include <linux/net.h>
36#include <linux/sysrq.h>
37#include <linux/highuid.h>
38#include <linux/writeback.h>
39#include <linux/ratelimit.h>
40#include <linux/hugetlb.h>
41#include <linux/initrd.h>
42#include <linux/key.h>
43#include <linux/times.h>
44#include <linux/limits.h>
45#include <linux/dcache.h>
46#include <linux/syscalls.h>
47#include <linux/vmstat.h>
48#include <linux/nfs_fs.h>
49#include <linux/acpi.h>
50#include <linux/reboot.h>
51#include <linux/ftrace.h>
52#include <linux/slow-work.h>
53#include <linux/perf_event.h>
54#include <linux/kprobes.h>
55
56#include <asm/uaccess.h>
57#include <asm/processor.h>
58
59#ifdef CONFIG_X86
60#include <asm/nmi.h>
61#include <asm/stacktrace.h>
62#include <asm/io.h>
63#endif
64#ifdef CONFIG_BSD_PROCESS_ACCT
65#include <linux/acct.h>
66#endif
67#ifdef CONFIG_RT_MUTEXES
68#include <linux/rtmutex.h>
69#endif
70#if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_LOCK_STAT)
71#include <linux/lockdep.h>
72#endif
73#ifdef CONFIG_CHR_DEV_SG
74#include <scsi/sg.h>
75#endif
76
77
78#if defined(CONFIG_SYSCTL)
79
80/* External variables not in a header file. */
81extern int sysctl_overcommit_memory;
82extern int sysctl_overcommit_ratio;
83extern int sysctl_panic_on_oom;
84extern int sysctl_oom_kill_allocating_task;
85extern int sysctl_oom_dump_tasks;
86extern int max_threads;
87extern int core_uses_pid;
88extern int suid_dumpable;
89extern char core_pattern[];
90extern unsigned int core_pipe_limit;
91extern int pid_max;
92extern int min_free_kbytes;
93extern int pid_max_min, pid_max_max;
94extern int sysctl_drop_caches;
95extern int percpu_pagelist_fraction;
96extern int compat_log;
97extern int latencytop_enabled;
98extern int sysctl_nr_open_min, sysctl_nr_open_max;
99#ifndef CONFIG_MMU
100extern int sysctl_nr_trim_pages;
101#endif
102#ifdef CONFIG_BLOCK
103extern int blk_iopoll_enabled;
104#endif
105
106/* Constants used for minimum and maximum */
107#ifdef CONFIG_DETECT_SOFTLOCKUP
108static int sixty = 60;
109static int neg_one = -1;
110#endif
111
112static int zero;
113static int __maybe_unused one = 1;
114static int __maybe_unused two = 2;
115static unsigned long one_ul = 1;
116static int one_hundred = 100;
117#ifdef CONFIG_PRINTK
118static int ten_thousand = 10000;
119#endif
120
121/* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
122static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;
123
124/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
125static int maxolduid = 65535;
126static int minolduid;
127static int min_percpu_pagelist_fract = 8;
128
129static int ngroups_max = NGROUPS_MAX;
130
131#ifdef CONFIG_SPARC
132#include <asm/system.h>
133#endif
134
135#ifdef CONFIG_SPARC64
136extern int sysctl_tsb_ratio;
137#endif
138
139#ifdef __hppa__
140extern int pwrsw_enabled;
141extern int unaligned_enabled;
142#endif
143
144#ifdef CONFIG_S390
145#ifdef CONFIG_MATHEMU
146extern int sysctl_ieee_emulation_warnings;
147#endif
148extern int sysctl_userprocess_debug;
149extern int spin_retry;
150#endif
151
152#ifdef CONFIG_IA64
153extern int no_unaligned_warning;
154extern int unaligned_dump_stack;
155#endif
156
157extern struct ratelimit_state printk_ratelimit_state;
158
159#ifdef CONFIG_PROC_SYSCTL
160static int proc_do_cad_pid(struct ctl_table *table, int write,
161          void __user *buffer, size_t *lenp, loff_t *ppos);
162static int proc_taint(struct ctl_table *table, int write,
163                   void __user *buffer, size_t *lenp, loff_t *ppos);
164#endif
165
166static struct ctl_table root_table[];
167static struct ctl_table_root sysctl_table_root;
168static struct ctl_table_header root_table_header = {
169    .count = 1,
170    .ctl_table = root_table,
171    .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),
172    .root = &sysctl_table_root,
173    .set = &sysctl_table_root.default_set,
174};
175static struct ctl_table_root sysctl_table_root = {
176    .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
177    .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
178};
179
180static struct ctl_table kern_table[];
181static struct ctl_table vm_table[];
182static struct ctl_table fs_table[];
183static struct ctl_table debug_table[];
184static struct ctl_table dev_table[];
185extern struct ctl_table random_table[];
186#ifdef CONFIG_INOTIFY_USER
187extern struct ctl_table inotify_table[];
188#endif
189#ifdef CONFIG_EPOLL
190extern struct ctl_table epoll_table[];
191#endif
192
193#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
194int sysctl_legacy_va_layout;
195#endif
196
197/* The default sysctl tables: */
198
199static struct ctl_table root_table[] = {
200    {
201        .procname = "kernel",
202        .mode = 0555,
203        .child = kern_table,
204    },
205    {
206        .procname = "vm",
207        .mode = 0555,
208        .child = vm_table,
209    },
210    {
211        .procname = "fs",
212        .mode = 0555,
213        .child = fs_table,
214    },
215    {
216        .procname = "debug",
217        .mode = 0555,
218        .child = debug_table,
219    },
220    {
221        .procname = "dev",
222        .mode = 0555,
223        .child = dev_table,
224    },
225/*
226 * NOTE: do not add new entries to this table unless you have read
227 * Documentation/sysctl/ctl_unnumbered.txt
228 */
229    { }
230};
231
232#ifdef CONFIG_SCHED_DEBUG
233static int min_sched_granularity_ns = 100000; /* 100 usecs */
234static int max_sched_granularity_ns = NSEC_PER_SEC; /* 1 second */
235static int min_wakeup_granularity_ns; /* 0 usecs */
236static int max_wakeup_granularity_ns = NSEC_PER_SEC; /* 1 second */
237static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
238static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
239static int min_sched_shares_ratelimit = 100000; /* 100 usec */
240static int max_sched_shares_ratelimit = NSEC_PER_SEC; /* 1 second */
241#endif
242
243static struct ctl_table kern_table[] = {
244    {
245        .procname = "sched_child_runs_first",
246        .data = &sysctl_sched_child_runs_first,
247        .maxlen = sizeof(unsigned int),
248        .mode = 0644,
249        .proc_handler = proc_dointvec,
250    },
251#ifdef CONFIG_SCHED_DEBUG
252    {
253        .procname = "sched_min_granularity_ns",
254        .data = &sysctl_sched_min_granularity,
255        .maxlen = sizeof(unsigned int),
256        .mode = 0644,
257        .proc_handler = sched_proc_update_handler,
258        .extra1 = &min_sched_granularity_ns,
259        .extra2 = &max_sched_granularity_ns,
260    },
261    {
262        .procname = "sched_latency_ns",
263        .data = &sysctl_sched_latency,
264        .maxlen = sizeof(unsigned int),
265        .mode = 0644,
266        .proc_handler = sched_proc_update_handler,
267        .extra1 = &min_sched_granularity_ns,
268        .extra2 = &max_sched_granularity_ns,
269    },
270    {
271        .procname = "sched_wakeup_granularity_ns",
272        .data = &sysctl_sched_wakeup_granularity,
273        .maxlen = sizeof(unsigned int),
274        .mode = 0644,
275        .proc_handler = sched_proc_update_handler,
276        .extra1 = &min_wakeup_granularity_ns,
277        .extra2 = &max_wakeup_granularity_ns,
278    },
279    {
280        .procname = "sched_shares_ratelimit",
281        .data = &sysctl_sched_shares_ratelimit,
282        .maxlen = sizeof(unsigned int),
283        .mode = 0644,
284        .proc_handler = sched_proc_update_handler,
285        .extra1 = &min_sched_shares_ratelimit,
286        .extra2 = &max_sched_shares_ratelimit,
287    },
288    {
289        .procname = "sched_tunable_scaling",
290        .data = &sysctl_sched_tunable_scaling,
291        .maxlen = sizeof(enum sched_tunable_scaling),
292        .mode = 0644,
293        .proc_handler = sched_proc_update_handler,
294        .extra1 = &min_sched_tunable_scaling,
295        .extra2 = &max_sched_tunable_scaling,
296    },
297    {
298        .procname = "sched_shares_thresh",
299        .data = &sysctl_sched_shares_thresh,
300        .maxlen = sizeof(unsigned int),
301        .mode = 0644,
302        .proc_handler = proc_dointvec_minmax,
303        .extra1 = &zero,
304    },
305    {
306        .procname = "sched_migration_cost",
307        .data = &sysctl_sched_migration_cost,
308        .maxlen = sizeof(unsigned int),
309        .mode = 0644,
310        .proc_handler = proc_dointvec,
311    },
312    {
313        .procname = "sched_nr_migrate",
314        .data = &sysctl_sched_nr_migrate,
315        .maxlen = sizeof(unsigned int),
316        .mode = 0644,
317        .proc_handler = proc_dointvec,
318    },
319    {
320        .procname = "sched_time_avg",
321        .data = &sysctl_sched_time_avg,
322        .maxlen = sizeof(unsigned int),
323        .mode = 0644,
324        .proc_handler = proc_dointvec,
325    },
326    {
327        .procname = "timer_migration",
328        .data = &sysctl_timer_migration,
329        .maxlen = sizeof(unsigned int),
330        .mode = 0644,
331        .proc_handler = proc_dointvec_minmax,
332        .extra1 = &zero,
333        .extra2 = &one,
334    },
335#endif
336    {
337        .procname = "sched_rt_period_us",
338        .data = &sysctl_sched_rt_period,
339        .maxlen = sizeof(unsigned int),
340        .mode = 0644,
341        .proc_handler = sched_rt_handler,
342    },
343    {
344        .procname = "sched_rt_runtime_us",
345        .data = &sysctl_sched_rt_runtime,
346        .maxlen = sizeof(int),
347        .mode = 0644,
348        .proc_handler = sched_rt_handler,
349    },
350    {
351        .procname = "sched_compat_yield",
352        .data = &sysctl_sched_compat_yield,
353        .maxlen = sizeof(unsigned int),
354        .mode = 0644,
355        .proc_handler = proc_dointvec,
356    },
357#ifdef CONFIG_PROVE_LOCKING
358    {
359        .procname = "prove_locking",
360        .data = &prove_locking,
361        .maxlen = sizeof(int),
362        .mode = 0644,
363        .proc_handler = proc_dointvec,
364    },
365#endif
366#ifdef CONFIG_LOCK_STAT
367    {
368        .procname = "lock_stat",
369        .data = &lock_stat,
370        .maxlen = sizeof(int),
371        .mode = 0644,
372        .proc_handler = proc_dointvec,
373    },
374#endif
375    {
376        .procname = "panic",
377        .data = &panic_timeout,
378        .maxlen = sizeof(int),
379        .mode = 0644,
380        .proc_handler = proc_dointvec,
381    },
382    {
383        .procname = "core_uses_pid",
384        .data = &core_uses_pid,
385        .maxlen = sizeof(int),
386        .mode = 0644,
387        .proc_handler = proc_dointvec,
388    },
389    {
390        .procname = "core_pattern",
391        .data = core_pattern,
392        .maxlen = CORENAME_MAX_SIZE,
393        .mode = 0644,
394        .proc_handler = proc_dostring,
395    },
396    {
397        .procname = "core_pipe_limit",
398        .data = &core_pipe_limit,
399        .maxlen = sizeof(unsigned int),
400        .mode = 0644,
401        .proc_handler = proc_dointvec,
402    },
403#ifdef CONFIG_PROC_SYSCTL
404    {
405        .procname = "tainted",
406        .maxlen = sizeof(long),
407        .mode = 0644,
408        .proc_handler = proc_taint,
409    },
410#endif
411#ifdef CONFIG_LATENCYTOP
412    {
413        .procname = "latencytop",
414        .data = &latencytop_enabled,
415        .maxlen = sizeof(int),
416        .mode = 0644,
417        .proc_handler = proc_dointvec,
418    },
419#endif
420#ifdef CONFIG_BLK_DEV_INITRD
421    {
422        .procname = "real-root-dev",
423        .data = &real_root_dev,
424        .maxlen = sizeof(int),
425        .mode = 0644,
426        .proc_handler = proc_dointvec,
427    },
428#endif
429    {
430        .procname = "print-fatal-signals",
431        .data = &print_fatal_signals,
432        .maxlen = sizeof(int),
433        .mode = 0644,
434        .proc_handler = proc_dointvec,
435    },
436#ifdef CONFIG_SPARC
437    {
438        .procname = "reboot-cmd",
439        .data = reboot_command,
440        .maxlen = 256,
441        .mode = 0644,
442        .proc_handler = proc_dostring,
443    },
444    {
445        .procname = "stop-a",
446        .data = &stop_a_enabled,
447        .maxlen = sizeof (int),
448        .mode = 0644,
449        .proc_handler = proc_dointvec,
450    },
451    {
452        .procname = "scons-poweroff",
453        .data = &scons_pwroff,
454        .maxlen = sizeof (int),
455        .mode = 0644,
456        .proc_handler = proc_dointvec,
457    },
458#endif
459#ifdef CONFIG_SPARC64
460    {
461        .procname = "tsb-ratio",
462        .data = &sysctl_tsb_ratio,
463        .maxlen = sizeof (int),
464        .mode = 0644,
465        .proc_handler = proc_dointvec,
466    },
467#endif
468#ifdef __hppa__
469    {
470        .procname = "soft-power",
471        .data = &pwrsw_enabled,
472        .maxlen = sizeof (int),
473         .mode = 0644,
474        .proc_handler = proc_dointvec,
475    },
476    {
477        .procname = "unaligned-trap",
478        .data = &unaligned_enabled,
479        .maxlen = sizeof (int),
480        .mode = 0644,
481        .proc_handler = proc_dointvec,
482    },
483#endif
484    {
485        .procname = "ctrl-alt-del",
486        .data = &C_A_D,
487        .maxlen = sizeof(int),
488        .mode = 0644,
489        .proc_handler = proc_dointvec,
490    },
491#ifdef CONFIG_FUNCTION_TRACER
492    {
493        .procname = "ftrace_enabled",
494        .data = &ftrace_enabled,
495        .maxlen = sizeof(int),
496        .mode = 0644,
497        .proc_handler = ftrace_enable_sysctl,
498    },
499#endif
500#ifdef CONFIG_STACK_TRACER
501    {
502        .procname = "stack_tracer_enabled",
503        .data = &stack_tracer_enabled,
504        .maxlen = sizeof(int),
505        .mode = 0644,
506        .proc_handler = stack_trace_sysctl,
507    },
508#endif
509#ifdef CONFIG_TRACING
510    {
511        .procname = "ftrace_dump_on_oops",
512        .data = &ftrace_dump_on_oops,
513        .maxlen = sizeof(int),
514        .mode = 0644,
515        .proc_handler = proc_dointvec,
516    },
517#endif
518#ifdef CONFIG_MODULES
519    {
520        .procname = "modprobe",
521        .data = &modprobe_path,
522        .maxlen = KMOD_PATH_LEN,
523        .mode = 0644,
524        .proc_handler = proc_dostring,
525    },
526    {
527        .procname = "modules_disabled",
528        .data = &modules_disabled,
529        .maxlen = sizeof(int),
530        .mode = 0644,
531        /* only handle a transition from default "0" to "1" */
532        .proc_handler = proc_dointvec_minmax,
533        .extra1 = &one,
534        .extra2 = &one,
535    },
536#endif
537#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
538    {
539        .procname = "hotplug",
540        .data = &uevent_helper,
541        .maxlen = UEVENT_HELPER_PATH_LEN,
542        .mode = 0644,
543        .proc_handler = proc_dostring,
544    },
545#endif
546#ifdef CONFIG_CHR_DEV_SG
547    {
548        .procname = "sg-big-buff",
549        .data = &sg_big_buff,
550        .maxlen = sizeof (int),
551        .mode = 0444,
552        .proc_handler = proc_dointvec,
553    },
554#endif
555#ifdef CONFIG_BSD_PROCESS_ACCT
556    {
557        .procname = "acct",
558        .data = &acct_parm,
559        .maxlen = 3*sizeof(int),
560        .mode = 0644,
561        .proc_handler = proc_dointvec,
562    },
563#endif
564#ifdef CONFIG_MAGIC_SYSRQ
565    {
566        .procname = "sysrq",
567        .data = &__sysrq_enabled,
568        .maxlen = sizeof (int),
569        .mode = 0644,
570        .proc_handler = proc_dointvec,
571    },
572#endif
573#ifdef CONFIG_PROC_SYSCTL
574    {
575        .procname = "cad_pid",
576        .data = NULL,
577        .maxlen = sizeof (int),
578        .mode = 0600,
579        .proc_handler = proc_do_cad_pid,
580    },
581#endif
582    {
583        .procname = "threads-max",
584        .data = &max_threads,
585        .maxlen = sizeof(int),
586        .mode = 0644,
587        .proc_handler = proc_dointvec,
588    },
589    {
590        .procname = "random",
591        .mode = 0555,
592        .child = random_table,
593    },
594    {
595        .procname = "overflowuid",
596        .data = &overflowuid,
597        .maxlen = sizeof(int),
598        .mode = 0644,
599        .proc_handler = proc_dointvec_minmax,
600        .extra1 = &minolduid,
601        .extra2 = &maxolduid,
602    },
603    {
604        .procname = "overflowgid",
605        .data = &overflowgid,
606        .maxlen = sizeof(int),
607        .mode = 0644,
608        .proc_handler = proc_dointvec_minmax,
609        .extra1 = &minolduid,
610        .extra2 = &maxolduid,
611    },
612#ifdef CONFIG_S390
613#ifdef CONFIG_MATHEMU
614    {
615        .procname = "ieee_emulation_warnings",
616        .data = &sysctl_ieee_emulation_warnings,
617        .maxlen = sizeof(int),
618        .mode = 0644,
619        .proc_handler = proc_dointvec,
620    },
621#endif
622    {
623        .procname = "userprocess_debug",
624        .data = &sysctl_userprocess_debug,
625        .maxlen = sizeof(int),
626        .mode = 0644,
627        .proc_handler = proc_dointvec,
628    },
629#endif
630    {
631        .procname = "pid_max",
632        .data = &pid_max,
633        .maxlen = sizeof (int),
634        .mode = 0644,
635        .proc_handler = proc_dointvec_minmax,
636        .extra1 = &pid_max_min,
637        .extra2 = &pid_max_max,
638    },
639    {
640        .procname = "panic_on_oops",
641        .data = &panic_on_oops,
642        .maxlen = sizeof(int),
643        .mode = 0644,
644        .proc_handler = proc_dointvec,
645    },
646#if defined CONFIG_PRINTK
647    {
648        .procname = "printk",
649        .data = &console_loglevel,
650        .maxlen = 4*sizeof(int),
651        .mode = 0644,
652        .proc_handler = proc_dointvec,
653    },
654    {
655        .procname = "printk_ratelimit",
656        .data = &printk_ratelimit_state.interval,
657        .maxlen = sizeof(int),
658        .mode = 0644,
659        .proc_handler = proc_dointvec_jiffies,
660    },
661    {
662        .procname = "printk_ratelimit_burst",
663        .data = &printk_ratelimit_state.burst,
664        .maxlen = sizeof(int),
665        .mode = 0644,
666        .proc_handler = proc_dointvec,
667    },
668    {
669        .procname = "printk_delay",
670        .data = &printk_delay_msec,
671        .maxlen = sizeof(int),
672        .mode = 0644,
673        .proc_handler = proc_dointvec_minmax,
674        .extra1 = &zero,
675        .extra2 = &ten_thousand,
676    },
677#endif
678    {
679        .procname = "ngroups_max",
680        .data = &ngroups_max,
681        .maxlen = sizeof (int),
682        .mode = 0444,
683        .proc_handler = proc_dointvec,
684    },
685#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
686    {
687        .procname = "unknown_nmi_panic",
688        .data = &unknown_nmi_panic,
689        .maxlen = sizeof (int),
690        .mode = 0644,
691        .proc_handler = proc_dointvec,
692    },
693    {
694        .procname = "nmi_watchdog",
695        .data = &nmi_watchdog_enabled,
696        .maxlen = sizeof (int),
697        .mode = 0644,
698        .proc_handler = proc_nmi_enabled,
699    },
700#endif
701#if defined(CONFIG_X86)
702    {
703        .procname = "panic_on_unrecovered_nmi",
704        .data = &panic_on_unrecovered_nmi,
705        .maxlen = sizeof(int),
706        .mode = 0644,
707        .proc_handler = proc_dointvec,
708    },
709    {
710        .procname = "panic_on_io_nmi",
711        .data = &panic_on_io_nmi,
712        .maxlen = sizeof(int),
713        .mode = 0644,
714        .proc_handler = proc_dointvec,
715    },
716    {
717        .procname = "bootloader_type",
718        .data = &bootloader_type,
719        .maxlen = sizeof (int),
720        .mode = 0444,
721        .proc_handler = proc_dointvec,
722    },
723    {
724        .procname = "bootloader_version",
725        .data = &bootloader_version,
726        .maxlen = sizeof (int),
727        .mode = 0444,
728        .proc_handler = proc_dointvec,
729    },
730    {
731        .procname = "kstack_depth_to_print",
732        .data = &kstack_depth_to_print,
733        .maxlen = sizeof(int),
734        .mode = 0644,
735        .proc_handler = proc_dointvec,
736    },
737    {
738        .procname = "io_delay_type",
739        .data = &io_delay_type,
740        .maxlen = sizeof(int),
741        .mode = 0644,
742        .proc_handler = proc_dointvec,
743    },
744#endif
745#if defined(CONFIG_MMU)
746    {
747        .procname = "randomize_va_space",
748        .data = &randomize_va_space,
749        .maxlen = sizeof(int),
750        .mode = 0644,
751        .proc_handler = proc_dointvec,
752    },
753#endif
754#if defined(CONFIG_S390) && defined(CONFIG_SMP)
755    {
756        .procname = "spin_retry",
757        .data = &spin_retry,
758        .maxlen = sizeof (int),
759        .mode = 0644,
760        .proc_handler = proc_dointvec,
761    },
762#endif
763#if defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
764    {
765        .procname = "acpi_video_flags",
766        .data = &acpi_realmode_flags,
767        .maxlen = sizeof (unsigned long),
768        .mode = 0644,
769        .proc_handler = proc_doulongvec_minmax,
770    },
771#endif
772#ifdef CONFIG_IA64
773    {
774        .procname = "ignore-unaligned-usertrap",
775        .data = &no_unaligned_warning,
776        .maxlen = sizeof (int),
777         .mode = 0644,
778        .proc_handler = proc_dointvec,
779    },
780    {
781        .procname = "unaligned-dump-stack",
782        .data = &unaligned_dump_stack,
783        .maxlen = sizeof (int),
784        .mode = 0644,
785        .proc_handler = proc_dointvec,
786    },
787#endif
788#ifdef CONFIG_DETECT_SOFTLOCKUP
789    {
790        .procname = "softlockup_panic",
791        .data = &softlockup_panic,
792        .maxlen = sizeof(int),
793        .mode = 0644,
794        .proc_handler = proc_dointvec_minmax,
795        .extra1 = &zero,
796        .extra2 = &one,
797    },
798    {
799        .procname = "softlockup_thresh",
800        .data = &softlockup_thresh,
801        .maxlen = sizeof(int),
802        .mode = 0644,
803        .proc_handler = proc_dosoftlockup_thresh,
804        .extra1 = &neg_one,
805        .extra2 = &sixty,
806    },
807#endif
808#ifdef CONFIG_DETECT_HUNG_TASK
809    {
810        .procname = "hung_task_panic",
811        .data = &sysctl_hung_task_panic,
812        .maxlen = sizeof(int),
813        .mode = 0644,
814        .proc_handler = proc_dointvec_minmax,
815        .extra1 = &zero,
816        .extra2 = &one,
817    },
818    {
819        .procname = "hung_task_check_count",
820        .data = &sysctl_hung_task_check_count,
821        .maxlen = sizeof(unsigned long),
822        .mode = 0644,
823        .proc_handler = proc_doulongvec_minmax,
824    },
825    {
826        .procname = "hung_task_timeout_secs",
827        .data = &sysctl_hung_task_timeout_secs,
828        .maxlen = sizeof(unsigned long),
829        .mode = 0644,
830        .proc_handler = proc_dohung_task_timeout_secs,
831    },
832    {
833        .procname = "hung_task_warnings",
834        .data = &sysctl_hung_task_warnings,
835        .maxlen = sizeof(unsigned long),
836        .mode = 0644,
837        .proc_handler = proc_doulongvec_minmax,
838    },
839#endif
840#ifdef CONFIG_COMPAT
841    {
842        .procname = "compat-log",
843        .data = &compat_log,
844        .maxlen = sizeof (int),
845         .mode = 0644,
846        .proc_handler = proc_dointvec,
847    },
848#endif
849#ifdef CONFIG_RT_MUTEXES
850    {
851        .procname = "max_lock_depth",
852        .data = &max_lock_depth,
853        .maxlen = sizeof(int),
854        .mode = 0644,
855        .proc_handler = proc_dointvec,
856    },
857#endif
858    {
859        .procname = "poweroff_cmd",
860        .data = &poweroff_cmd,
861        .maxlen = POWEROFF_CMD_PATH_LEN,
862        .mode = 0644,
863        .proc_handler = proc_dostring,
864    },
865#ifdef CONFIG_KEYS
866    {
867        .procname = "keys",
868        .mode = 0555,
869        .child = key_sysctls,
870    },
871#endif
872#ifdef CONFIG_RCU_TORTURE_TEST
873    {
874        .procname = "rcutorture_runnable",
875        .data = &rcutorture_runnable,
876        .maxlen = sizeof(int),
877        .mode = 0644,
878        .proc_handler = proc_dointvec,
879    },
880#endif
881#ifdef CONFIG_SLOW_WORK
882    {
883        .procname = "slow-work",
884        .mode = 0555,
885        .child = slow_work_sysctls,
886    },
887#endif
888#ifdef CONFIG_PERF_EVENTS
889    {
890        .procname = "perf_event_paranoid",
891        .data = &sysctl_perf_event_paranoid,
892        .maxlen = sizeof(sysctl_perf_event_paranoid),
893        .mode = 0644,
894        .proc_handler = proc_dointvec,
895    },
896    {
897        .procname = "perf_event_mlock_kb",
898        .data = &sysctl_perf_event_mlock,
899        .maxlen = sizeof(sysctl_perf_event_mlock),
900        .mode = 0644,
901        .proc_handler = proc_dointvec,
902    },
903    {
904        .procname = "perf_event_max_sample_rate",
905        .data = &sysctl_perf_event_sample_rate,
906        .maxlen = sizeof(sysctl_perf_event_sample_rate),
907        .mode = 0644,
908        .proc_handler = proc_dointvec,
909    },
910#endif
911#ifdef CONFIG_KMEMCHECK
912    {
913        .procname = "kmemcheck",
914        .data = &kmemcheck_enabled,
915        .maxlen = sizeof(int),
916        .mode = 0644,
917        .proc_handler = proc_dointvec,
918    },
919#endif
920#ifdef CONFIG_BLOCK
921    {
922        .procname = "blk_iopoll",
923        .data = &blk_iopoll_enabled,
924        .maxlen = sizeof(int),
925        .mode = 0644,
926        .proc_handler = proc_dointvec,
927    },
928#endif
929/*
930 * NOTE: do not add new entries to this table unless you have read
931 * Documentation/sysctl/ctl_unnumbered.txt
932 */
933    { }
934};
935
936static struct ctl_table vm_table[] = {
937    {
938        .procname = "overcommit_memory",
939        .data = &sysctl_overcommit_memory,
940        .maxlen = sizeof(sysctl_overcommit_memory),
941        .mode = 0644,
942        .proc_handler = proc_dointvec,
943    },
944    {
945        .procname = "panic_on_oom",
946        .data = &sysctl_panic_on_oom,
947        .maxlen = sizeof(sysctl_panic_on_oom),
948        .mode = 0644,
949        .proc_handler = proc_dointvec,
950    },
951    {
952        .procname = "oom_kill_allocating_task",
953        .data = &sysctl_oom_kill_allocating_task,
954        .maxlen = sizeof(sysctl_oom_kill_allocating_task),
955        .mode = 0644,
956        .proc_handler = proc_dointvec,
957    },
958    {
959        .procname = "oom_dump_tasks",
960        .data = &sysctl_oom_dump_tasks,
961        .maxlen = sizeof(sysctl_oom_dump_tasks),
962        .mode = 0644,
963        .proc_handler = proc_dointvec,
964    },
965    {
966        .procname = "overcommit_ratio",
967        .data = &sysctl_overcommit_ratio,
968        .maxlen = sizeof(sysctl_overcommit_ratio),
969        .mode = 0644,
970        .proc_handler = proc_dointvec,
971    },
972    {
973        .procname = "page-cluster",
974        .data = &page_cluster,
975        .maxlen = sizeof(int),
976        .mode = 0644,
977        .proc_handler = proc_dointvec,
978    },
979    {
980        .procname = "dirty_background_ratio",
981        .data = &dirty_background_ratio,
982        .maxlen = sizeof(dirty_background_ratio),
983        .mode = 0644,
984        .proc_handler = dirty_background_ratio_handler,
985        .extra1 = &zero,
986        .extra2 = &one_hundred,
987    },
988    {
989        .procname = "dirty_background_bytes",
990        .data = &dirty_background_bytes,
991        .maxlen = sizeof(dirty_background_bytes),
992        .mode = 0644,
993        .proc_handler = dirty_background_bytes_handler,
994        .extra1 = &one_ul,
995    },
996    {
997        .procname = "dirty_ratio",
998        .data = &vm_dirty_ratio,
999        .maxlen = sizeof(vm_dirty_ratio),
1000        .mode = 0644,
1001        .proc_handler = dirty_ratio_handler,
1002        .extra1 = &zero,
1003        .extra2 = &one_hundred,
1004    },
1005    {
1006        .procname = "dirty_bytes",
1007        .data = &vm_dirty_bytes,
1008        .maxlen = sizeof(vm_dirty_bytes),
1009        .mode = 0644,
1010        .proc_handler = dirty_bytes_handler,
1011        .extra1 = &dirty_bytes_min,
1012    },
1013    {
1014        .procname = "dirty_writeback_centisecs",
1015        .data = &dirty_writeback_interval,
1016        .maxlen = sizeof(dirty_writeback_interval),
1017        .mode = 0644,
1018        .proc_handler = dirty_writeback_centisecs_handler,
1019    },
1020    {
1021        .procname = "dirty_expire_centisecs",
1022        .data = &dirty_expire_interval,
1023        .maxlen = sizeof(dirty_expire_interval),
1024        .mode = 0644,
1025        .proc_handler = proc_dointvec,
1026    },
1027    {
1028        .procname = "nr_pdflush_threads",
1029        .data = &nr_pdflush_threads,
1030        .maxlen = sizeof nr_pdflush_threads,
1031        .mode = 0444 /* read-only*/,
1032        .proc_handler = proc_dointvec,
1033    },
1034    {
1035        .procname = "swappiness",
1036        .data = &vm_swappiness,
1037        .maxlen = sizeof(vm_swappiness),
1038        .mode = 0644,
1039        .proc_handler = proc_dointvec_minmax,
1040        .extra1 = &zero,
1041        .extra2 = &one_hundred,
1042    },
1043#ifdef CONFIG_HUGETLB_PAGE
1044    {
1045        .procname = "nr_hugepages",
1046        .data = NULL,
1047        .maxlen = sizeof(unsigned long),
1048        .mode = 0644,
1049        .proc_handler = hugetlb_sysctl_handler,
1050        .extra1 = (void *)&hugetlb_zero,
1051        .extra2 = (void *)&hugetlb_infinity,
1052    },
1053#ifdef CONFIG_NUMA
1054    {
1055        .procname = "nr_hugepages_mempolicy",
1056        .data = NULL,
1057        .maxlen = sizeof(unsigned long),
1058        .mode = 0644,
1059        .proc_handler = &hugetlb_mempolicy_sysctl_handler,
1060        .extra1 = (void *)&hugetlb_zero,
1061        .extra2 = (void *)&hugetlb_infinity,
1062    },
1063#endif
1064     {
1065        .procname = "hugetlb_shm_group",
1066        .data = &sysctl_hugetlb_shm_group,
1067        .maxlen = sizeof(gid_t),
1068        .mode = 0644,
1069        .proc_handler = proc_dointvec,
1070     },
1071     {
1072        .procname = "hugepages_treat_as_movable",
1073        .data = &hugepages_treat_as_movable,
1074        .maxlen = sizeof(int),
1075        .mode = 0644,
1076        .proc_handler = hugetlb_treat_movable_handler,
1077    },
1078    {
1079        .procname = "nr_overcommit_hugepages",
1080        .data = NULL,
1081        .maxlen = sizeof(unsigned long),
1082        .mode = 0644,
1083        .proc_handler = hugetlb_overcommit_handler,
1084        .extra1 = (void *)&hugetlb_zero,
1085        .extra2 = (void *)&hugetlb_infinity,
1086    },
1087#endif
1088    {
1089        .procname = "lowmem_reserve_ratio",
1090        .data = &sysctl_lowmem_reserve_ratio,
1091        .maxlen = sizeof(sysctl_lowmem_reserve_ratio),
1092        .mode = 0644,
1093        .proc_handler = lowmem_reserve_ratio_sysctl_handler,
1094    },
1095    {
1096        .procname = "drop_caches",
1097        .data = &sysctl_drop_caches,
1098        .maxlen = sizeof(int),
1099        .mode = 0644,
1100        .proc_handler = drop_caches_sysctl_handler,
1101    },
1102    {
1103        .procname = "min_free_kbytes",
1104        .data = &min_free_kbytes,
1105        .maxlen = sizeof(min_free_kbytes),
1106        .mode = 0644,
1107        .proc_handler = min_free_kbytes_sysctl_handler,
1108        .extra1 = &zero,
1109    },
1110    {
1111        .procname = "percpu_pagelist_fraction",
1112        .data = &percpu_pagelist_fraction,
1113        .maxlen = sizeof(percpu_pagelist_fraction),
1114        .mode = 0644,
1115        .proc_handler = percpu_pagelist_fraction_sysctl_handler,
1116        .extra1 = &min_percpu_pagelist_fract,
1117    },
1118#ifdef CONFIG_MMU
1119    {
1120        .procname = "max_map_count",
1121        .data = &sysctl_max_map_count,
1122        .maxlen = sizeof(sysctl_max_map_count),
1123        .mode = 0644,
1124        .proc_handler = proc_dointvec_minmax,
1125        .extra1 = &zero,
1126    },
1127#else
1128    {
1129        .procname = "nr_trim_pages",
1130        .data = &sysctl_nr_trim_pages,
1131        .maxlen = sizeof(sysctl_nr_trim_pages),
1132        .mode = 0644,
1133        .proc_handler = proc_dointvec_minmax,
1134        .extra1 = &zero,
1135    },
1136#endif
1137    {
1138        .procname = "laptop_mode",
1139        .data = &laptop_mode,
1140        .maxlen = sizeof(laptop_mode),
1141        .mode = 0644,
1142        .proc_handler = proc_dointvec_jiffies,
1143    },
1144    {
1145        .procname = "block_dump",
1146        .data = &block_dump,
1147        .maxlen = sizeof(block_dump),
1148        .mode = 0644,
1149        .proc_handler = proc_dointvec,
1150        .extra1 = &zero,
1151    },
1152    {
1153        .procname = "vfs_cache_pressure",
1154        .data = &sysctl_vfs_cache_pressure,
1155        .maxlen = sizeof(sysctl_vfs_cache_pressure),
1156        .mode = 0644,
1157        .proc_handler = proc_dointvec,
1158        .extra1 = &zero,
1159    },
1160#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
1161    {
1162        .procname = "legacy_va_layout",
1163        .data = &sysctl_legacy_va_layout,
1164        .maxlen = sizeof(sysctl_legacy_va_layout),
1165        .mode = 0644,
1166        .proc_handler = proc_dointvec,
1167        .extra1 = &zero,
1168    },
1169#endif
1170#ifdef CONFIG_NUMA
1171    {
1172        .procname = "zone_reclaim_mode",
1173        .data = &zone_reclaim_mode,
1174        .maxlen = sizeof(zone_reclaim_mode),
1175        .mode = 0644,
1176        .proc_handler = proc_dointvec,
1177        .extra1 = &zero,
1178    },
1179    {
1180        .procname = "min_unmapped_ratio",
1181        .data = &sysctl_min_unmapped_ratio,
1182        .maxlen = sizeof(sysctl_min_unmapped_ratio),
1183        .mode = 0644,
1184        .proc_handler = sysctl_min_unmapped_ratio_sysctl_handler,
1185        .extra1 = &zero,
1186        .extra2 = &one_hundred,
1187    },
1188    {
1189        .procname = "min_slab_ratio",
1190        .data = &sysctl_min_slab_ratio,
1191        .maxlen = sizeof(sysctl_min_slab_ratio),
1192        .mode = 0644,
1193        .proc_handler = sysctl_min_slab_ratio_sysctl_handler,
1194        .extra1 = &zero,
1195        .extra2 = &one_hundred,
1196    },
1197#endif
1198#ifdef CONFIG_SMP
1199    {
1200        .procname = "stat_interval",
1201        .data = &sysctl_stat_interval,
1202        .maxlen = sizeof(sysctl_stat_interval),
1203        .mode = 0644,
1204        .proc_handler = proc_dointvec_jiffies,
1205    },
1206#endif
1207#ifdef CONFIG_MMU
1208    {
1209        .procname = "mmap_min_addr",
1210        .data = &dac_mmap_min_addr,
1211        .maxlen = sizeof(unsigned long),
1212        .mode = 0644,
1213        .proc_handler = mmap_min_addr_handler,
1214    },
1215#endif
1216#ifdef CONFIG_NUMA
1217    {
1218        .procname = "numa_zonelist_order",
1219        .data = &numa_zonelist_order,
1220        .maxlen = NUMA_ZONELIST_ORDER_LEN,
1221        .mode = 0644,
1222        .proc_handler = numa_zonelist_order_handler,
1223    },
1224#endif
1225#if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
1226   (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
1227    {
1228        .procname = "vdso_enabled",
1229        .data = &vdso_enabled,
1230        .maxlen = sizeof(vdso_enabled),
1231        .mode = 0644,
1232        .proc_handler = proc_dointvec,
1233        .extra1 = &zero,
1234    },
1235#endif
1236#ifdef CONFIG_HIGHMEM
1237    {
1238        .procname = "highmem_is_dirtyable",
1239        .data = &vm_highmem_is_dirtyable,
1240        .maxlen = sizeof(vm_highmem_is_dirtyable),
1241        .mode = 0644,
1242        .proc_handler = proc_dointvec_minmax,
1243        .extra1 = &zero,
1244        .extra2 = &one,
1245    },
1246#endif
1247    {
1248        .procname = "scan_unevictable_pages",
1249        .data = &scan_unevictable_pages,
1250        .maxlen = sizeof(scan_unevictable_pages),
1251        .mode = 0644,
1252        .proc_handler = scan_unevictable_handler,
1253    },
1254#ifdef CONFIG_MEMORY_FAILURE
1255    {
1256        .procname = "memory_failure_early_kill",
1257        .data = &sysctl_memory_failure_early_kill,
1258        .maxlen = sizeof(sysctl_memory_failure_early_kill),
1259        .mode = 0644,
1260        .proc_handler = proc_dointvec_minmax,
1261        .extra1 = &zero,
1262        .extra2 = &one,
1263    },
1264    {
1265        .procname = "memory_failure_recovery",
1266        .data = &sysctl_memory_failure_recovery,
1267        .maxlen = sizeof(sysctl_memory_failure_recovery),
1268        .mode = 0644,
1269        .proc_handler = proc_dointvec_minmax,
1270        .extra1 = &zero,
1271        .extra2 = &one,
1272    },
1273#endif
1274
1275/*
1276 * NOTE: do not add new entries to this table unless you have read
1277 * Documentation/sysctl/ctl_unnumbered.txt
1278 */
1279    { }
1280};
1281
1282#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1283static struct ctl_table binfmt_misc_table[] = {
1284    { }
1285};
1286#endif
1287
1288static struct ctl_table fs_table[] = {
1289    {
1290        .procname = "inode-nr",
1291        .data = &inodes_stat,
1292        .maxlen = 2*sizeof(int),
1293        .mode = 0444,
1294        .proc_handler = proc_dointvec,
1295    },
1296    {
1297        .procname = "inode-state",
1298        .data = &inodes_stat,
1299        .maxlen = 7*sizeof(int),
1300        .mode = 0444,
1301        .proc_handler = proc_dointvec,
1302    },
1303    {
1304        .procname = "file-nr",
1305        .data = &files_stat,
1306        .maxlen = 3*sizeof(int),
1307        .mode = 0444,
1308        .proc_handler = proc_nr_files,
1309    },
1310    {
1311        .procname = "file-max",
1312        .data = &files_stat.max_files,
1313        .maxlen = sizeof(int),
1314        .mode = 0644,
1315        .proc_handler = proc_dointvec,
1316    },
1317    {
1318        .procname = "nr_open",
1319        .data = &sysctl_nr_open,
1320        .maxlen = sizeof(int),
1321        .mode = 0644,
1322        .proc_handler = proc_dointvec_minmax,
1323        .extra1 = &sysctl_nr_open_min,
1324        .extra2 = &sysctl_nr_open_max,
1325    },
1326    {
1327        .procname = "dentry-state",
1328        .data = &dentry_stat,
1329        .maxlen = 6*sizeof(int),
1330        .mode = 0444,
1331        .proc_handler = proc_dointvec,
1332    },
1333    {
1334        .procname = "overflowuid",
1335        .data = &fs_overflowuid,
1336        .maxlen = sizeof(int),
1337        .mode = 0644,
1338        .proc_handler = proc_dointvec_minmax,
1339        .extra1 = &minolduid,
1340        .extra2 = &maxolduid,
1341    },
1342    {
1343        .procname = "overflowgid",
1344        .data = &fs_overflowgid,
1345        .maxlen = sizeof(int),
1346        .mode = 0644,
1347        .proc_handler = proc_dointvec_minmax,
1348        .extra1 = &minolduid,
1349        .extra2 = &maxolduid,
1350    },
1351#ifdef CONFIG_FILE_LOCKING
1352    {
1353        .procname = "leases-enable",
1354        .data = &leases_enable,
1355        .maxlen = sizeof(int),
1356        .mode = 0644,
1357        .proc_handler = proc_dointvec,
1358    },
1359#endif
1360#ifdef CONFIG_DNOTIFY
1361    {
1362        .procname = "dir-notify-enable",
1363        .data = &dir_notify_enable,
1364        .maxlen = sizeof(int),
1365        .mode = 0644,
1366        .proc_handler = proc_dointvec,
1367    },
1368#endif
1369#ifdef CONFIG_MMU
1370#ifdef CONFIG_FILE_LOCKING
1371    {
1372        .procname = "lease-break-time",
1373        .data = &lease_break_time,
1374        .maxlen = sizeof(int),
1375        .mode = 0644,
1376        .proc_handler = proc_dointvec,
1377    },
1378#endif
1379#ifdef CONFIG_AIO
1380    {
1381        .procname = "aio-nr",
1382        .data = &aio_nr,
1383        .maxlen = sizeof(aio_nr),
1384        .mode = 0444,
1385        .proc_handler = proc_doulongvec_minmax,
1386    },
1387    {
1388        .procname = "aio-max-nr",
1389        .data = &aio_max_nr,
1390        .maxlen = sizeof(aio_max_nr),
1391        .mode = 0644,
1392        .proc_handler = proc_doulongvec_minmax,
1393    },
1394#endif /* CONFIG_AIO */
1395#ifdef CONFIG_INOTIFY_USER
1396    {
1397        .procname = "inotify",
1398        .mode = 0555,
1399        .child = inotify_table,
1400    },
1401#endif
1402#ifdef CONFIG_EPOLL
1403    {
1404        .procname = "epoll",
1405        .mode = 0555,
1406        .child = epoll_table,
1407    },
1408#endif
1409#endif
1410    {
1411        .procname = "suid_dumpable",
1412        .data = &suid_dumpable,
1413        .maxlen = sizeof(int),
1414        .mode = 0644,
1415        .proc_handler = proc_dointvec_minmax,
1416        .extra1 = &zero,
1417        .extra2 = &two,
1418    },
1419#if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1420    {
1421        .procname = "binfmt_misc",
1422        .mode = 0555,
1423        .child = binfmt_misc_table,
1424    },
1425#endif
1426/*
1427 * NOTE: do not add new entries to this table unless you have read
1428 * Documentation/sysctl/ctl_unnumbered.txt
1429 */
1430    { }
1431};
1432
1433static struct ctl_table debug_table[] = {
1434#if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_SPARC)
1435    {
1436        .procname = "exception-trace",
1437        .data = &show_unhandled_signals,
1438        .maxlen = sizeof(int),
1439        .mode = 0644,
1440        .proc_handler = proc_dointvec
1441    },
1442#endif
1443#if defined(CONFIG_OPTPROBES)
1444    {
1445        .procname = "kprobes-optimization",
1446        .data = &sysctl_kprobes_optimization,
1447        .maxlen = sizeof(int),
1448        .mode = 0644,
1449        .proc_handler = proc_kprobes_optimization_handler,
1450        .extra1 = &zero,
1451        .extra2 = &one,
1452    },
1453#endif
1454    { }
1455};
1456
1457static struct ctl_table dev_table[] = {
1458    { }
1459};
1460
1461static DEFINE_SPINLOCK(sysctl_lock);
1462
1463/* called under sysctl_lock */
1464static int use_table(struct ctl_table_header *p)
1465{
1466    if (unlikely(p->unregistering))
1467        return 0;
1468    p->used++;
1469    return 1;
1470}
1471
1472/* called under sysctl_lock */
1473static void unuse_table(struct ctl_table_header *p)
1474{
1475    if (!--p->used)
1476        if (unlikely(p->unregistering))
1477            complete(p->unregistering);
1478}
1479
1480/* called under sysctl_lock, will reacquire if has to wait */
1481static void start_unregistering(struct ctl_table_header *p)
1482{
1483    /*
1484     * if p->used is 0, nobody will ever touch that entry again;
1485     * we'll eliminate all paths to it before dropping sysctl_lock
1486     */
1487    if (unlikely(p->used)) {
1488        struct completion wait;
1489        init_completion(&wait);
1490        p->unregistering = &wait;
1491        spin_unlock(&sysctl_lock);
1492        wait_for_completion(&wait);
1493        spin_lock(&sysctl_lock);
1494    } else {
1495        /* anything non-NULL; we'll never dereference it */
1496        p->unregistering = ERR_PTR(-EINVAL);
1497    }
1498    /*
1499     * do not remove from the list until nobody holds it; walking the
1500     * list in do_sysctl() relies on that.
1501     */
1502    list_del_init(&p->ctl_entry);
1503}
1504
1505void sysctl_head_get(struct ctl_table_header *head)
1506{
1507    spin_lock(&sysctl_lock);
1508    head->count++;
1509    spin_unlock(&sysctl_lock);
1510}
1511
1512void sysctl_head_put(struct ctl_table_header *head)
1513{
1514    spin_lock(&sysctl_lock);
1515    if (!--head->count)
1516        kfree(head);
1517    spin_unlock(&sysctl_lock);
1518}
1519
1520struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
1521{
1522    if (!head)
1523        BUG();
1524    spin_lock(&sysctl_lock);
1525    if (!use_table(head))
1526        head = ERR_PTR(-ENOENT);
1527    spin_unlock(&sysctl_lock);
1528    return head;
1529}
1530
1531void sysctl_head_finish(struct ctl_table_header *head)
1532{
1533    if (!head)
1534        return;
1535    spin_lock(&sysctl_lock);
1536    unuse_table(head);
1537    spin_unlock(&sysctl_lock);
1538}
1539
1540static struct ctl_table_set *
1541lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
1542{
1543    struct ctl_table_set *set = &root->default_set;
1544    if (root->lookup)
1545        set = root->lookup(root, namespaces);
1546    return set;
1547}
1548
1549static struct list_head *
1550lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
1551{
1552    struct ctl_table_set *set = lookup_header_set(root, namespaces);
1553    return &set->list;
1554}
1555
1556struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
1557                        struct ctl_table_header *prev)
1558{
1559    struct ctl_table_root *root;
1560    struct list_head *header_list;
1561    struct ctl_table_header *head;
1562    struct list_head *tmp;
1563
1564    spin_lock(&sysctl_lock);
1565    if (prev) {
1566        head = prev;
1567        tmp = &prev->ctl_entry;
1568        unuse_table(prev);
1569        goto next;
1570    }
1571    tmp = &root_table_header.ctl_entry;
1572    for (;;) {
1573        head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1574
1575        if (!use_table(head))
1576            goto next;
1577        spin_unlock(&sysctl_lock);
1578        return head;
1579    next:
1580        root = head->root;
1581        tmp = tmp->next;
1582        header_list = lookup_header_list(root, namespaces);
1583        if (tmp != header_list)
1584            continue;
1585
1586        do {
1587            root = list_entry(root->root_list.next,
1588                    struct ctl_table_root, root_list);
1589            if (root == &sysctl_table_root)
1590                goto out;
1591            header_list = lookup_header_list(root, namespaces);
1592        } while (list_empty(header_list));
1593        tmp = header_list->next;
1594    }
1595out:
1596    spin_unlock(&sysctl_lock);
1597    return NULL;
1598}
1599
1600struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1601{
1602    return __sysctl_head_next(current->nsproxy, prev);
1603}
1604
1605void register_sysctl_root(struct ctl_table_root *root)
1606{
1607    spin_lock(&sysctl_lock);
1608    list_add_tail(&root->root_list, &sysctl_table_root.root_list);
1609    spin_unlock(&sysctl_lock);
1610}
1611
1612/*
1613 * sysctl_perm does NOT grant the superuser all rights automatically, because
1614 * some sysctl variables are readonly even to root.
1615 */
1616
1617static int test_perm(int mode, int op)
1618{
1619    if (!current_euid())
1620        mode >>= 6;
1621    else if (in_egroup_p(0))
1622        mode >>= 3;
1623    if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
1624        return 0;
1625    return -EACCES;
1626}
1627
1628int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
1629{
1630    int error;
1631    int mode;
1632
1633    error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
1634    if (error)
1635        return error;
1636
1637    if (root->permissions)
1638        mode = root->permissions(root, current->nsproxy, table);
1639    else
1640        mode = table->mode;
1641
1642    return test_perm(mode, op);
1643}
1644
1645static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1646{
1647    for (; table->procname; table++) {
1648        table->parent = parent;
1649        if (table->child)
1650            sysctl_set_parent(table, table->child);
1651    }
1652}
1653
1654static __init int sysctl_init(void)
1655{
1656    sysctl_set_parent(NULL, root_table);
1657#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1658    {
1659        int err;
1660        err = sysctl_check_table(current->nsproxy, root_table);
1661    }
1662#endif
1663    return 0;
1664}
1665
1666core_initcall(sysctl_init);
1667
1668static struct ctl_table *is_branch_in(struct ctl_table *branch,
1669                      struct ctl_table *table)
1670{
1671    struct ctl_table *p;
1672    const char *s = branch->procname;
1673
1674    /* branch should have named subdirectory as its first element */
1675    if (!s || !branch->child)
1676        return NULL;
1677
1678    /* ... and nothing else */
1679    if (branch[1].procname)
1680        return NULL;
1681
1682    /* table should contain subdirectory with the same name */
1683    for (p = table; p->procname; p++) {
1684        if (!p->child)
1685            continue;
1686        if (p->procname && strcmp(p->procname, s) == 0)
1687            return p;
1688    }
1689    return NULL;
1690}
1691
1692/* see if attaching q to p would be an improvement */
1693static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
1694{
1695    struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
1696    struct ctl_table *next;
1697    int is_better = 0;
1698    int not_in_parent = !p->attached_by;
1699
1700    while ((next = is_branch_in(by, to)) != NULL) {
1701        if (by == q->attached_by)
1702            is_better = 1;
1703        if (to == p->attached_by)
1704            not_in_parent = 1;
1705        by = by->child;
1706        to = next->child;
1707    }
1708
1709    if (is_better && not_in_parent) {
1710        q->attached_by = by;
1711        q->attached_to = to;
1712        q->parent = p;
1713    }
1714}
1715
1716/**
1717 * __register_sysctl_paths - register a sysctl hierarchy
1718 * @root: List of sysctl headers to register on
1719 * @namespaces: Data to compute which lists of sysctl entries are visible
1720 * @path: The path to the directory the sysctl table is in.
1721 * @table: the top-level table structure
1722 *
1723 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1724 * array. A completely 0 filled entry terminates the table.
1725 *
1726 * The members of the &struct ctl_table structure are used as follows:
1727 *
1728 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1729 * enter a sysctl file
1730 *
1731 * data - a pointer to data for use by proc_handler
1732 *
1733 * maxlen - the maximum size in bytes of the data
1734 *
1735 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1736 *
1737 * child - a pointer to the child sysctl table if this entry is a directory, or
1738 * %NULL.
1739 *
1740 * proc_handler - the text handler routine (described below)
1741 *
1742 * de - for internal use by the sysctl routines
1743 *
1744 * extra1, extra2 - extra pointers usable by the proc handler routines
1745 *
1746 * Leaf nodes in the sysctl tree will be represented by a single file
1747 * under /proc; non-leaf nodes will be represented by directories.
1748 *
1749 * sysctl(2) can automatically manage read and write requests through
1750 * the sysctl table. The data and maxlen fields of the ctl_table
1751 * struct enable minimal validation of the values being written to be
1752 * performed, and the mode field allows minimal authentication.
1753 *
1754 * There must be a proc_handler routine for any terminal nodes
1755 * mirrored under /proc/sys (non-terminals are handled by a built-in
1756 * directory handler). Several default handlers are available to
1757 * cover common cases -
1758 *
1759 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1760 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1761 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1762 *
1763 * It is the handler's job to read the input buffer from user memory
1764 * and process it. The handler should return 0 on success.
1765 *
1766 * This routine returns %NULL on a failure to register, and a pointer
1767 * to the table header on success.
1768 */
1769struct ctl_table_header *__register_sysctl_paths(
1770    struct ctl_table_root *root,
1771    struct nsproxy *namespaces,
1772    const struct ctl_path *path, struct ctl_table *table)
1773{
1774    struct ctl_table_header *header;
1775    struct ctl_table *new, **prevp;
1776    unsigned int n, npath;
1777    struct ctl_table_set *set;
1778
1779    /* Count the path components */
1780    for (npath = 0; path[npath].procname; ++npath)
1781        ;
1782
1783    /*
1784     * For each path component, allocate a 2-element ctl_table array.
1785     * The first array element will be filled with the sysctl entry
1786     * for this, the second will be the sentinel (procname == 0).
1787     *
1788     * We allocate everything in one go so that we don't have to
1789     * worry about freeing additional memory in unregister_sysctl_table.
1790     */
1791    header = kzalloc(sizeof(struct ctl_table_header) +
1792             (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
1793    if (!header)
1794        return NULL;
1795
1796    new = (struct ctl_table *) (header + 1);
1797
1798    /* Now connect the dots */
1799    prevp = &header->ctl_table;
1800    for (n = 0; n < npath; ++n, ++path) {
1801        /* Copy the procname */
1802        new->procname = path->procname;
1803        new->mode = 0555;
1804
1805        *prevp = new;
1806        prevp = &new->child;
1807
1808        new += 2;
1809    }
1810    *prevp = table;
1811    header->ctl_table_arg = table;
1812
1813    INIT_LIST_HEAD(&header->ctl_entry);
1814    header->used = 0;
1815    header->unregistering = NULL;
1816    header->root = root;
1817    sysctl_set_parent(NULL, header->ctl_table);
1818    header->count = 1;
1819#ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1820    if (sysctl_check_table(namespaces, header->ctl_table)) {
1821        kfree(header);
1822        return NULL;
1823    }
1824#endif
1825    spin_lock(&sysctl_lock);
1826    header->set = lookup_header_set(root, namespaces);
1827    header->attached_by = header->ctl_table;
1828    header->attached_to = root_table;
1829    header->parent = &root_table_header;
1830    for (set = header->set; set; set = set->parent) {
1831        struct ctl_table_header *p;
1832        list_for_each_entry(p, &set->list, ctl_entry) {
1833            if (p->unregistering)
1834                continue;
1835            try_attach(p, header);
1836        }
1837    }
1838    header->parent->count++;
1839    list_add_tail(&header->ctl_entry, &header->set->list);
1840    spin_unlock(&sysctl_lock);
1841
1842    return header;
1843}
1844
1845/**
1846 * register_sysctl_table_path - register a sysctl table hierarchy
1847 * @path: The path to the directory the sysctl table is in.
1848 * @table: the top-level table structure
1849 *
1850 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1851 * array. A completely 0 filled entry terminates the table.
1852 *
1853 * See __register_sysctl_paths for more details.
1854 */
1855struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1856                        struct ctl_table *table)
1857{
1858    return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1859                    path, table);
1860}
1861
1862/**
1863 * register_sysctl_table - register a sysctl table hierarchy
1864 * @table: the top-level table structure
1865 *
1866 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1867 * array. A completely 0 filled entry terminates the table.
1868 *
1869 * See register_sysctl_paths for more details.
1870 */
1871struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1872{
1873    static const struct ctl_path null_path[] = { {} };
1874
1875    return register_sysctl_paths(null_path, table);
1876}
1877
1878/**
1879 * unregister_sysctl_table - unregister a sysctl table hierarchy
1880 * @header: the header returned from register_sysctl_table
1881 *
1882 * Unregisters the sysctl table and all children. proc entries may not
1883 * actually be removed until they are no longer used by anyone.
1884 */
1885void unregister_sysctl_table(struct ctl_table_header * header)
1886{
1887    might_sleep();
1888
1889    if (header == NULL)
1890        return;
1891
1892    spin_lock(&sysctl_lock);
1893    start_unregistering(header);
1894    if (!--header->parent->count) {
1895        WARN_ON(1);
1896        kfree(header->parent);
1897    }
1898    if (!--header->count)
1899        kfree(header);
1900    spin_unlock(&sysctl_lock);
1901}
1902
1903int sysctl_is_seen(struct ctl_table_header *p)
1904{
1905    struct ctl_table_set *set = p->set;
1906    int res;
1907    spin_lock(&sysctl_lock);
1908    if (p->unregistering)
1909        res = 0;
1910    else if (!set->is_seen)
1911        res = 1;
1912    else
1913        res = set->is_seen(set);
1914    spin_unlock(&sysctl_lock);
1915    return res;
1916}
1917
1918void setup_sysctl_set(struct ctl_table_set *p,
1919    struct ctl_table_set *parent,
1920    int (*is_seen)(struct ctl_table_set *))
1921{
1922    INIT_LIST_HEAD(&p->list);
1923    p->parent = parent ? parent : &sysctl_table_root.default_set;
1924    p->is_seen = is_seen;
1925}
1926
1927#else /* !CONFIG_SYSCTL */
1928struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
1929{
1930    return NULL;
1931}
1932
1933struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1934                            struct ctl_table *table)
1935{
1936    return NULL;
1937}
1938
1939void unregister_sysctl_table(struct ctl_table_header * table)
1940{
1941}
1942
1943void setup_sysctl_set(struct ctl_table_set *p,
1944    struct ctl_table_set *parent,
1945    int (*is_seen)(struct ctl_table_set *))
1946{
1947}
1948
1949void sysctl_head_put(struct ctl_table_header *head)
1950{
1951}
1952
1953#endif /* CONFIG_SYSCTL */
1954
1955/*
1956 * /proc/sys support
1957 */
1958
1959#ifdef CONFIG_PROC_SYSCTL
1960
1961static int _proc_do_string(void* data, int maxlen, int write,
1962               void __user *buffer,
1963               size_t *lenp, loff_t *ppos)
1964{
1965    size_t len;
1966    char __user *p;
1967    char c;
1968
1969    if (!data || !maxlen || !*lenp) {
1970        *lenp = 0;
1971        return 0;
1972    }
1973
1974    if (write) {
1975        len = 0;
1976        p = buffer;
1977        while (len < *lenp) {
1978            if (get_user(c, p++))
1979                return -EFAULT;
1980            if (c == 0 || c == '\n')
1981                break;
1982            len++;
1983        }
1984        if (len >= maxlen)
1985            len = maxlen-1;
1986        if(copy_from_user(data, buffer, len))
1987            return -EFAULT;
1988        ((char *) data)[len] = 0;
1989        *ppos += *lenp;
1990    } else {
1991        len = strlen(data);
1992        if (len > maxlen)
1993            len = maxlen;
1994
1995        if (*ppos > len) {
1996            *lenp = 0;
1997            return 0;
1998        }
1999
2000        data += *ppos;
2001        len -= *ppos;
2002
2003        if (len > *lenp)
2004            len = *lenp;
2005        if (len)
2006            if(copy_to_user(buffer, data, len))
2007                return -EFAULT;
2008        if (len < *lenp) {
2009            if(put_user('\n', ((char __user *) buffer) + len))
2010                return -EFAULT;
2011            len++;
2012        }
2013        *lenp = len;
2014        *ppos += len;
2015    }
2016    return 0;
2017}
2018
2019/**
2020 * proc_dostring - read a string sysctl
2021 * @table: the sysctl table
2022 * @write: %TRUE if this is a write to the sysctl file
2023 * @buffer: the user buffer
2024 * @lenp: the size of the user buffer
2025 * @ppos: file position
2026 *
2027 * Reads/writes a string from/to the user buffer. If the kernel
2028 * buffer provided is not large enough to hold the string, the
2029 * string is truncated. The copied string is %NULL-terminated.
2030 * If the string is being read by the user process, it is copied
2031 * and a newline '\n' is added. It is truncated if the buffer is
2032 * not large enough.
2033 *
2034 * Returns 0 on success.
2035 */
2036int proc_dostring(struct ctl_table *table, int write,
2037          void __user *buffer, size_t *lenp, loff_t *ppos)
2038{
2039    return _proc_do_string(table->data, table->maxlen, write,
2040                   buffer, lenp, ppos);
2041}
2042
2043
2044static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
2045                 int *valp,
2046                 int write, void *data)
2047{
2048    if (write) {
2049        *valp = *negp ? -*lvalp : *lvalp;
2050    } else {
2051        int val = *valp;
2052        if (val < 0) {
2053            *negp = -1;
2054            *lvalp = (unsigned long)-val;
2055        } else {
2056            *negp = 0;
2057            *lvalp = (unsigned long)val;
2058        }
2059    }
2060    return 0;
2061}
2062
2063static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
2064          int write, void __user *buffer,
2065          size_t *lenp, loff_t *ppos,
2066          int (*conv)(int *negp, unsigned long *lvalp, int *valp,
2067                  int write, void *data),
2068          void *data)
2069{
2070#define TMPBUFLEN 21
2071    int *i, vleft, first = 1, neg;
2072    unsigned long lval;
2073    size_t left, len;
2074    
2075    char buf[TMPBUFLEN], *p;
2076    char __user *s = buffer;
2077    
2078    if (!tbl_data || !table->maxlen || !*lenp ||
2079        (*ppos && !write)) {
2080        *lenp = 0;
2081        return 0;
2082    }
2083    
2084    i = (int *) tbl_data;
2085    vleft = table->maxlen / sizeof(*i);
2086    left = *lenp;
2087
2088    if (!conv)
2089        conv = do_proc_dointvec_conv;
2090
2091    for (; left && vleft--; i++, first=0) {
2092        if (write) {
2093            while (left) {
2094                char c;
2095                if (get_user(c, s))
2096                    return -EFAULT;
2097                if (!isspace(c))
2098                    break;
2099                left--;
2100                s++;
2101            }
2102            if (!left)
2103                break;
2104            neg = 0;
2105            len = left;
2106            if (len > sizeof(buf) - 1)
2107                len = sizeof(buf) - 1;
2108            if (copy_from_user(buf, s, len))
2109                return -EFAULT;
2110            buf[len] = 0;
2111            p = buf;
2112            if (*p == '-' && left > 1) {
2113                neg = 1;
2114                p++;
2115            }
2116            if (*p < '0' || *p > '9')
2117                break;
2118
2119            lval = simple_strtoul(p, &p, 0);
2120
2121            len = p-buf;
2122            if ((len < left) && *p && !isspace(*p))
2123                break;
2124            s += len;
2125            left -= len;
2126
2127            if (conv(&neg, &lval, i, 1, data))
2128                break;
2129        } else {
2130            p = buf;
2131            if (!first)
2132                *p++ = '\t';
2133    
2134            if (conv(&neg, &lval, i, 0, data))
2135                break;
2136
2137            sprintf(p, "%s%lu", neg ? "-" : "", lval);
2138            len = strlen(buf);
2139            if (len > left)
2140                len = left;
2141            if(copy_to_user(s, buf, len))
2142                return -EFAULT;
2143            left -= len;
2144            s += len;
2145        }
2146    }
2147
2148    if (!write && !first && left) {
2149        if(put_user('\n', s))
2150            return -EFAULT;
2151        left--, s++;
2152    }
2153    if (write) {
2154        while (left) {
2155            char c;
2156            if (get_user(c, s++))
2157                return -EFAULT;
2158            if (!isspace(c))
2159                break;
2160            left--;
2161        }
2162    }
2163    if (write && first)
2164        return -EINVAL;
2165    *lenp -= left;
2166    *ppos += *lenp;
2167    return 0;
2168#undef TMPBUFLEN
2169}
2170
2171static int do_proc_dointvec(struct ctl_table *table, int write,
2172          void __user *buffer, size_t *lenp, loff_t *ppos,
2173          int (*conv)(int *negp, unsigned long *lvalp, int *valp,
2174                  int write, void *data),
2175          void *data)
2176{
2177    return __do_proc_dointvec(table->data, table, write,
2178            buffer, lenp, ppos, conv, data);
2179}
2180
2181/**
2182 * proc_dointvec - read a vector of integers
2183 * @table: the sysctl table
2184 * @write: %TRUE if this is a write to the sysctl file
2185 * @buffer: the user buffer
2186 * @lenp: the size of the user buffer
2187 * @ppos: file position
2188 *
2189 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2190 * values from/to the user buffer, treated as an ASCII string.
2191 *
2192 * Returns 0 on success.
2193 */
2194int proc_dointvec(struct ctl_table *table, int write,
2195             void __user *buffer, size_t *lenp, loff_t *ppos)
2196{
2197    return do_proc_dointvec(table,write,buffer,lenp,ppos,
2198                    NULL,NULL);
2199}
2200
2201/*
2202 * Taint values can only be increased
2203 * This means we can safely use a temporary.
2204 */
2205static int proc_taint(struct ctl_table *table, int write,
2206                   void __user *buffer, size_t *lenp, loff_t *ppos)
2207{
2208    struct ctl_table t;
2209    unsigned long tmptaint = get_taint();
2210    int err;
2211
2212    if (write && !capable(CAP_SYS_ADMIN))
2213        return -EPERM;
2214
2215    t = *table;
2216    t.data = &tmptaint;
2217    err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
2218    if (err < 0)
2219        return err;
2220
2221    if (write) {
2222        /*
2223         * Poor man's atomic or. Not worth adding a primitive
2224         * to everyone's atomic.h for this
2225         */
2226        int i;
2227        for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
2228            if ((tmptaint >> i) & 1)
2229                add_taint(i);
2230        }
2231    }
2232
2233    return err;
2234}
2235
2236struct do_proc_dointvec_minmax_conv_param {
2237    int *min;
2238    int *max;
2239};
2240
2241static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp,
2242                    int *valp,
2243                    int write, void *data)
2244{
2245    struct do_proc_dointvec_minmax_conv_param *param = data;
2246    if (write) {
2247        int val = *negp ? -*lvalp : *lvalp;
2248        if ((param->min && *param->min > val) ||
2249            (param->max && *param->max < val))
2250            return -EINVAL;
2251        *valp = val;
2252    } else {
2253        int val = *valp;
2254        if (val < 0) {
2255            *negp = -1;
2256            *lvalp = (unsigned long)-val;
2257        } else {
2258            *negp = 0;
2259            *lvalp = (unsigned long)val;
2260        }
2261    }
2262    return 0;
2263}
2264
2265/**
2266 * proc_dointvec_minmax - read a vector of integers with min/max values
2267 * @table: the sysctl table
2268 * @write: %TRUE if this is a write to the sysctl file
2269 * @buffer: the user buffer
2270 * @lenp: the size of the user buffer
2271 * @ppos: file position
2272 *
2273 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2274 * values from/to the user buffer, treated as an ASCII string.
2275 *
2276 * This routine will ensure the values are within the range specified by
2277 * table->extra1 (min) and table->extra2 (max).
2278 *
2279 * Returns 0 on success.
2280 */
2281int proc_dointvec_minmax(struct ctl_table *table, int write,
2282          void __user *buffer, size_t *lenp, loff_t *ppos)
2283{
2284    struct do_proc_dointvec_minmax_conv_param param = {
2285        .min = (int *) table->extra1,
2286        .max = (int *) table->extra2,
2287    };
2288    return do_proc_dointvec(table, write, buffer, lenp, ppos,
2289                do_proc_dointvec_minmax_conv, &param);
2290}
2291
2292static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
2293                     void __user *buffer,
2294                     size_t *lenp, loff_t *ppos,
2295                     unsigned long convmul,
2296                     unsigned long convdiv)
2297{
2298#define TMPBUFLEN 21
2299    unsigned long *i, *min, *max, val;
2300    int vleft, first=1, neg;
2301    size_t len, left;
2302    char buf[TMPBUFLEN], *p;
2303    char __user *s = buffer;
2304    
2305    if (!data || !table->maxlen || !*lenp ||
2306        (*ppos && !write)) {
2307        *lenp = 0;
2308        return 0;
2309    }
2310    
2311    i = (unsigned long *) data;
2312    min = (unsigned long *) table->extra1;
2313    max = (unsigned long *) table->extra2;
2314    vleft = table->maxlen / sizeof(unsigned long);
2315    left = *lenp;
2316    
2317    for (; left && vleft--; i++, min++, max++, first=0) {
2318        if (write) {
2319            while (left) {
2320                char c;
2321                if (get_user(c, s))
2322                    return -EFAULT;
2323                if (!isspace(c))
2324                    break;
2325                left--;
2326                s++;
2327            }
2328            if (!left)
2329                break;
2330            neg = 0;
2331            len = left;
2332            if (len > TMPBUFLEN-1)
2333                len = TMPBUFLEN-1;
2334            if (copy_from_user(buf, s, len))
2335                return -EFAULT;
2336            buf[len] = 0;
2337            p = buf;
2338            if (*p == '-' && left > 1) {
2339                neg = 1;
2340                p++;
2341            }
2342            if (*p < '0' || *p > '9')
2343                break;
2344            val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
2345            len = p-buf;
2346            if ((len < left) && *p && !isspace(*p))
2347                break;
2348            if (neg)
2349                val = -val;
2350            s += len;
2351            left -= len;
2352
2353            if(neg)
2354                continue;
2355            if ((min && val < *min) || (max && val > *max))
2356                continue;
2357            *i = val;
2358        } else {
2359            p = buf;
2360            if (!first)
2361                *p++ = '\t';
2362            sprintf(p, "%lu", convdiv * (*i) / convmul);
2363            len = strlen(buf);
2364            if (len > left)
2365                len = left;
2366            if(copy_to_user(s, buf, len))
2367                return -EFAULT;
2368            left -= len;
2369            s += len;
2370        }
2371    }
2372
2373    if (!write && !first && left) {
2374        if(put_user('\n', s))
2375            return -EFAULT;
2376        left--, s++;
2377    }
2378    if (write) {
2379        while (left) {
2380            char c;
2381            if (get_user(c, s++))
2382                return -EFAULT;
2383            if (!isspace(c))
2384                break;
2385            left--;
2386        }
2387    }
2388    if (write && first)
2389        return -EINVAL;
2390    *lenp -= left;
2391    *ppos += *lenp;
2392    return 0;
2393#undef TMPBUFLEN
2394}
2395
2396static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
2397                     void __user *buffer,
2398                     size_t *lenp, loff_t *ppos,
2399                     unsigned long convmul,
2400                     unsigned long convdiv)
2401{
2402    return __do_proc_doulongvec_minmax(table->data, table, write,
2403            buffer, lenp, ppos, convmul, convdiv);
2404}
2405
2406/**
2407 * proc_doulongvec_minmax - read a vector of long integers with min/max values
2408 * @table: the sysctl table
2409 * @write: %TRUE if this is a write to the sysctl file
2410 * @buffer: the user buffer
2411 * @lenp: the size of the user buffer
2412 * @ppos: file position
2413 *
2414 * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2415 * values from/to the user buffer, treated as an ASCII string.
2416 *
2417 * This routine will ensure the values are within the range specified by
2418 * table->extra1 (min) and table->extra2 (max).
2419 *
2420 * Returns 0 on success.
2421 */
2422int proc_doulongvec_minmax(struct ctl_table *table, int write,
2423               void __user *buffer, size_t *lenp, loff_t *ppos)
2424{
2425    return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
2426}
2427
2428/**
2429 * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2430 * @table: the sysctl table
2431 * @write: %TRUE if this is a write to the sysctl file
2432 * @buffer: the user buffer
2433 * @lenp: the size of the user buffer
2434 * @ppos: file position
2435 *
2436 * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2437 * values from/to the user buffer, treated as an ASCII string. The values
2438 * are treated as milliseconds, and converted to jiffies when they are stored.
2439 *
2440 * This routine will ensure the values are within the range specified by
2441 * table->extra1 (min) and table->extra2 (max).
2442 *
2443 * Returns 0 on success.
2444 */
2445int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2446                      void __user *buffer,
2447                      size_t *lenp, loff_t *ppos)
2448{
2449    return do_proc_doulongvec_minmax(table, write, buffer,
2450                     lenp, ppos, HZ, 1000l);
2451}
2452
2453
2454static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
2455                     int *valp,
2456                     int write, void *data)
2457{
2458    if (write) {
2459        if (*lvalp > LONG_MAX / HZ)
2460            return 1;
2461        *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2462    } else {
2463        int val = *valp;
2464        unsigned long lval;
2465        if (val < 0) {
2466            *negp = -1;
2467            lval = (unsigned long)-val;
2468        } else {
2469            *negp = 0;
2470            lval = (unsigned long)val;
2471        }
2472        *lvalp = lval / HZ;
2473    }
2474    return 0;
2475}
2476
2477static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
2478                        int *valp,
2479                        int write, void *data)
2480{
2481    if (write) {
2482        if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2483            return 1;
2484        *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2485    } else {
2486        int val = *valp;
2487        unsigned long lval;
2488        if (val < 0) {
2489            *negp = -1;
2490            lval = (unsigned long)-val;
2491        } else {
2492            *negp = 0;
2493            lval = (unsigned long)val;
2494        }
2495        *lvalp = jiffies_to_clock_t(lval);
2496    }
2497    return 0;
2498}
2499
2500static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
2501                        int *valp,
2502                        int write, void *data)
2503{
2504    if (write) {
2505        *valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2506    } else {
2507        int val = *valp;
2508        unsigned long lval;
2509        if (val < 0) {
2510            *negp = -1;
2511            lval = (unsigned long)-val;
2512        } else {
2513            *negp = 0;
2514            lval = (unsigned long)val;
2515        }
2516        *lvalp = jiffies_to_msecs(lval);
2517    }
2518    return 0;
2519}
2520
2521/**
2522 * proc_dointvec_jiffies - read a vector of integers as seconds
2523 * @table: the sysctl table
2524 * @write: %TRUE if this is a write to the sysctl file
2525 * @buffer: the user buffer
2526 * @lenp: the size of the user buffer
2527 * @ppos: file position
2528 *
2529 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2530 * values from/to the user buffer, treated as an ASCII string.
2531 * The values read are assumed to be in seconds, and are converted into
2532 * jiffies.
2533 *
2534 * Returns 0 on success.
2535 */
2536int proc_dointvec_jiffies(struct ctl_table *table, int write,
2537              void __user *buffer, size_t *lenp, loff_t *ppos)
2538{
2539    return do_proc_dointvec(table,write,buffer,lenp,ppos,
2540                    do_proc_dointvec_jiffies_conv,NULL);
2541}
2542
2543/**
2544 * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2545 * @table: the sysctl table
2546 * @write: %TRUE if this is a write to the sysctl file
2547 * @buffer: the user buffer
2548 * @lenp: the size of the user buffer
2549 * @ppos: pointer to the file position
2550 *
2551 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2552 * values from/to the user buffer, treated as an ASCII string.
2553 * The values read are assumed to be in 1/USER_HZ seconds, and
2554 * are converted into jiffies.
2555 *
2556 * Returns 0 on success.
2557 */
2558int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2559                 void __user *buffer, size_t *lenp, loff_t *ppos)
2560{
2561    return do_proc_dointvec(table,write,buffer,lenp,ppos,
2562                    do_proc_dointvec_userhz_jiffies_conv,NULL);
2563}
2564
2565/**
2566 * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2567 * @table: the sysctl table
2568 * @write: %TRUE if this is a write to the sysctl file
2569 * @buffer: the user buffer
2570 * @lenp: the size of the user buffer
2571 * @ppos: file position
2572 * @ppos: the current position in the file
2573 *
2574 * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2575 * values from/to the user buffer, treated as an ASCII string.
2576 * The values read are assumed to be in 1/1000 seconds, and
2577 * are converted into jiffies.
2578 *
2579 * Returns 0 on success.
2580 */
2581int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2582                 void __user *buffer, size_t *lenp, loff_t *ppos)
2583{
2584    return do_proc_dointvec(table, write, buffer, lenp, ppos,
2585                do_proc_dointvec_ms_jiffies_conv, NULL);
2586}
2587
2588static int proc_do_cad_pid(struct ctl_table *table, int write,
2589               void __user *buffer, size_t *lenp, loff_t *ppos)
2590{
2591    struct pid *new_pid;
2592    pid_t tmp;
2593    int r;
2594
2595    tmp = pid_vnr(cad_pid);
2596
2597    r = __do_proc_dointvec(&tmp, table, write, buffer,
2598                   lenp, ppos, NULL, NULL);
2599    if (r || !write)
2600        return r;
2601
2602    new_pid = find_get_pid(tmp);
2603    if (!new_pid)
2604        return -ESRCH;
2605
2606    put_pid(xchg(&cad_pid, new_pid));
2607    return 0;
2608}
2609
2610#else /* CONFIG_PROC_FS */
2611
2612int proc_dostring(struct ctl_table *table, int write,
2613          void __user *buffer, size_t *lenp, loff_t *ppos)
2614{
2615    return -ENOSYS;
2616}
2617
2618int proc_dointvec(struct ctl_table *table, int write,
2619          void __user *buffer, size_t *lenp, loff_t *ppos)
2620{
2621    return -ENOSYS;
2622}
2623
2624int proc_dointvec_minmax(struct ctl_table *table, int write,
2625            void __user *buffer, size_t *lenp, loff_t *ppos)
2626{
2627    return -ENOSYS;
2628}
2629
2630int proc_dointvec_jiffies(struct ctl_table *table, int write,
2631            void __user *buffer, size_t *lenp, loff_t *ppos)
2632{
2633    return -ENOSYS;
2634}
2635
2636int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2637            void __user *buffer, size_t *lenp, loff_t *ppos)
2638{
2639    return -ENOSYS;
2640}
2641
2642int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2643                 void __user *buffer, size_t *lenp, loff_t *ppos)
2644{
2645    return -ENOSYS;
2646}
2647
2648int proc_doulongvec_minmax(struct ctl_table *table, int write,
2649            void __user *buffer, size_t *lenp, loff_t *ppos)
2650{
2651    return -ENOSYS;
2652}
2653
2654int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2655                      void __user *buffer,
2656                      size_t *lenp, loff_t *ppos)
2657{
2658    return -ENOSYS;
2659}
2660
2661
2662#endif /* CONFIG_PROC_FS */
2663
2664/*
2665 * No sense putting this after each symbol definition, twice,
2666 * exception granted :-)
2667 */
2668EXPORT_SYMBOL(proc_dointvec);
2669EXPORT_SYMBOL(proc_dointvec_jiffies);
2670EXPORT_SYMBOL(proc_dointvec_minmax);
2671EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2672EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2673EXPORT_SYMBOL(proc_dostring);
2674EXPORT_SYMBOL(proc_doulongvec_minmax);
2675EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2676EXPORT_SYMBOL(register_sysctl_table);
2677EXPORT_SYMBOL(register_sysctl_paths);
2678EXPORT_SYMBOL(unregister_sysctl_table);
2679

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