xref: /linux/kernel/sysctl.c (revision 48c36c8f9a3e881953bb72deb55623a53795a684)
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/compaction.h>
41 #include <linux/hugetlb.h>
42 #include <linux/initrd.h>
43 #include <linux/key.h>
44 #include <linux/times.h>
45 #include <linux/limits.h>
46 #include <linux/dcache.h>
47 #include <linux/dnotify.h>
48 #include <linux/syscalls.h>
49 #include <linux/vmstat.h>
50 #include <linux/nfs_fs.h>
51 #include <linux/acpi.h>
52 #include <linux/reboot.h>
53 #include <linux/ftrace.h>
54 #include <linux/perf_event.h>
55 #include <linux/kprobes.h>
56 #include <linux/pipe_fs_i.h>
57 #include <linux/oom.h>
58 
59 #include <asm/uaccess.h>
60 #include <asm/processor.h>
61 
62 #ifdef CONFIG_X86
63 #include <asm/nmi.h>
64 #include <asm/stacktrace.h>
65 #include <asm/io.h>
66 #endif
67 #ifdef CONFIG_BSD_PROCESS_ACCT
68 #include <linux/acct.h>
69 #endif
70 #ifdef CONFIG_RT_MUTEXES
71 #include <linux/rtmutex.h>
72 #endif
73 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_LOCK_STAT)
74 #include <linux/lockdep.h>
75 #endif
76 #ifdef CONFIG_CHR_DEV_SG
77 #include <scsi/sg.h>
78 #endif
79 
80 #ifdef CONFIG_LOCKUP_DETECTOR
81 #include <linux/nmi.h>
82 #endif
83 
84 
85 #if defined(CONFIG_SYSCTL)
86 
87 /* External variables not in a header file. */
88 extern int sysctl_overcommit_memory;
89 extern int sysctl_overcommit_ratio;
90 extern int max_threads;
91 extern int core_uses_pid;
92 extern int suid_dumpable;
93 extern char core_pattern[];
94 extern unsigned int core_pipe_limit;
95 extern int pid_max;
96 extern int min_free_kbytes;
97 extern int pid_max_min, pid_max_max;
98 extern int sysctl_drop_caches;
99 extern int percpu_pagelist_fraction;
100 extern int compat_log;
101 extern int latencytop_enabled;
102 extern int sysctl_nr_open_min, sysctl_nr_open_max;
103 #ifndef CONFIG_MMU
104 extern int sysctl_nr_trim_pages;
105 #endif
106 #ifdef CONFIG_BLOCK
107 extern int blk_iopoll_enabled;
108 #endif
109 
110 /* Constants used for minimum and  maximum */
111 #ifdef CONFIG_LOCKUP_DETECTOR
112 static int sixty = 60;
113 static int neg_one = -1;
114 #endif
115 
116 static int zero;
117 static int __maybe_unused one = 1;
118 static int __maybe_unused two = 2;
119 static unsigned long one_ul = 1;
120 static int one_hundred = 100;
121 #ifdef CONFIG_PRINTK
122 static int ten_thousand = 10000;
123 #endif
124 
125 /* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
126 static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;
127 
128 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
129 static int maxolduid = 65535;
130 static int minolduid;
131 static int min_percpu_pagelist_fract = 8;
132 
133 static int ngroups_max = NGROUPS_MAX;
134 
135 #ifdef CONFIG_INOTIFY_USER
136 #include <linux/inotify.h>
137 #endif
138 #ifdef CONFIG_SPARC
139 #include <asm/system.h>
140 #endif
141 
142 #ifdef CONFIG_SPARC64
143 extern int sysctl_tsb_ratio;
144 #endif
145 
146 #ifdef __hppa__
147 extern int pwrsw_enabled;
148 extern int unaligned_enabled;
149 #endif
150 
151 #ifdef CONFIG_S390
152 #ifdef CONFIG_MATHEMU
153 extern int sysctl_ieee_emulation_warnings;
154 #endif
155 extern int sysctl_userprocess_debug;
156 extern int spin_retry;
157 #endif
158 
159 #ifdef CONFIG_IA64
160 extern int no_unaligned_warning;
161 extern int unaligned_dump_stack;
162 #endif
163 
164 #ifdef CONFIG_PROC_SYSCTL
165 static int proc_do_cad_pid(struct ctl_table *table, int write,
166 		  void __user *buffer, size_t *lenp, loff_t *ppos);
167 static int proc_taint(struct ctl_table *table, int write,
168 			       void __user *buffer, size_t *lenp, loff_t *ppos);
169 #endif
170 
171 #ifdef CONFIG_MAGIC_SYSRQ
172 static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */
173 
174 static int sysrq_sysctl_handler(ctl_table *table, int write,
175 				void __user *buffer, size_t *lenp,
176 				loff_t *ppos)
177 {
178 	int error;
179 
180 	error = proc_dointvec(table, write, buffer, lenp, ppos);
181 	if (error)
182 		return error;
183 
184 	if (write)
185 		sysrq_toggle_support(__sysrq_enabled);
186 
187 	return 0;
188 }
189 
190 #endif
191 
192 static struct ctl_table root_table[];
193 static struct ctl_table_root sysctl_table_root;
194 static struct ctl_table_header root_table_header = {
195 	.count = 1,
196 	.ctl_table = root_table,
197 	.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),
198 	.root = &sysctl_table_root,
199 	.set = &sysctl_table_root.default_set,
200 };
201 static struct ctl_table_root sysctl_table_root = {
202 	.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
203 	.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
204 };
205 
206 static struct ctl_table kern_table[];
207 static struct ctl_table vm_table[];
208 static struct ctl_table fs_table[];
209 static struct ctl_table debug_table[];
210 static struct ctl_table dev_table[];
211 extern struct ctl_table random_table[];
212 #ifdef CONFIG_EPOLL
213 extern struct ctl_table epoll_table[];
214 #endif
215 
216 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
217 int sysctl_legacy_va_layout;
218 #endif
219 
220 /* The default sysctl tables: */
221 
222 static struct ctl_table root_table[] = {
223 	{
224 		.procname	= "kernel",
225 		.mode		= 0555,
226 		.child		= kern_table,
227 	},
228 	{
229 		.procname	= "vm",
230 		.mode		= 0555,
231 		.child		= vm_table,
232 	},
233 	{
234 		.procname	= "fs",
235 		.mode		= 0555,
236 		.child		= fs_table,
237 	},
238 	{
239 		.procname	= "debug",
240 		.mode		= 0555,
241 		.child		= debug_table,
242 	},
243 	{
244 		.procname	= "dev",
245 		.mode		= 0555,
246 		.child		= dev_table,
247 	},
248 /*
249  * NOTE: do not add new entries to this table unless you have read
250  * Documentation/sysctl/ctl_unnumbered.txt
251  */
252 	{ }
253 };
254 
255 #ifdef CONFIG_SCHED_DEBUG
256 static int min_sched_granularity_ns = 100000;		/* 100 usecs */
257 static int max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
258 static int min_wakeup_granularity_ns;			/* 0 usecs */
259 static int max_wakeup_granularity_ns = NSEC_PER_SEC;	/* 1 second */
260 static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
261 static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
262 static int min_sched_shares_ratelimit = 100000; /* 100 usec */
263 static int max_sched_shares_ratelimit = NSEC_PER_SEC; /* 1 second */
264 #endif
265 
266 #ifdef CONFIG_COMPACTION
267 static int min_extfrag_threshold;
268 static int max_extfrag_threshold = 1000;
269 #endif
270 
271 static struct ctl_table kern_table[] = {
272 	{
273 		.procname	= "sched_child_runs_first",
274 		.data		= &sysctl_sched_child_runs_first,
275 		.maxlen		= sizeof(unsigned int),
276 		.mode		= 0644,
277 		.proc_handler	= proc_dointvec,
278 	},
279 #ifdef CONFIG_SCHED_DEBUG
280 	{
281 		.procname	= "sched_min_granularity_ns",
282 		.data		= &sysctl_sched_min_granularity,
283 		.maxlen		= sizeof(unsigned int),
284 		.mode		= 0644,
285 		.proc_handler	= sched_proc_update_handler,
286 		.extra1		= &min_sched_granularity_ns,
287 		.extra2		= &max_sched_granularity_ns,
288 	},
289 	{
290 		.procname	= "sched_latency_ns",
291 		.data		= &sysctl_sched_latency,
292 		.maxlen		= sizeof(unsigned int),
293 		.mode		= 0644,
294 		.proc_handler	= sched_proc_update_handler,
295 		.extra1		= &min_sched_granularity_ns,
296 		.extra2		= &max_sched_granularity_ns,
297 	},
298 	{
299 		.procname	= "sched_wakeup_granularity_ns",
300 		.data		= &sysctl_sched_wakeup_granularity,
301 		.maxlen		= sizeof(unsigned int),
302 		.mode		= 0644,
303 		.proc_handler	= sched_proc_update_handler,
304 		.extra1		= &min_wakeup_granularity_ns,
305 		.extra2		= &max_wakeup_granularity_ns,
306 	},
307 	{
308 		.procname	= "sched_shares_ratelimit",
309 		.data		= &sysctl_sched_shares_ratelimit,
310 		.maxlen		= sizeof(unsigned int),
311 		.mode		= 0644,
312 		.proc_handler	= sched_proc_update_handler,
313 		.extra1		= &min_sched_shares_ratelimit,
314 		.extra2		= &max_sched_shares_ratelimit,
315 	},
316 	{
317 		.procname	= "sched_tunable_scaling",
318 		.data		= &sysctl_sched_tunable_scaling,
319 		.maxlen		= sizeof(enum sched_tunable_scaling),
320 		.mode		= 0644,
321 		.proc_handler	= sched_proc_update_handler,
322 		.extra1		= &min_sched_tunable_scaling,
323 		.extra2		= &max_sched_tunable_scaling,
324 	},
325 	{
326 		.procname	= "sched_shares_thresh",
327 		.data		= &sysctl_sched_shares_thresh,
328 		.maxlen		= sizeof(unsigned int),
329 		.mode		= 0644,
330 		.proc_handler	= proc_dointvec_minmax,
331 		.extra1		= &zero,
332 	},
333 	{
334 		.procname	= "sched_migration_cost",
335 		.data		= &sysctl_sched_migration_cost,
336 		.maxlen		= sizeof(unsigned int),
337 		.mode		= 0644,
338 		.proc_handler	= proc_dointvec,
339 	},
340 	{
341 		.procname	= "sched_nr_migrate",
342 		.data		= &sysctl_sched_nr_migrate,
343 		.maxlen		= sizeof(unsigned int),
344 		.mode		= 0644,
345 		.proc_handler	= proc_dointvec,
346 	},
347 	{
348 		.procname	= "sched_time_avg",
349 		.data		= &sysctl_sched_time_avg,
350 		.maxlen		= sizeof(unsigned int),
351 		.mode		= 0644,
352 		.proc_handler	= proc_dointvec,
353 	},
354 	{
355 		.procname	= "timer_migration",
356 		.data		= &sysctl_timer_migration,
357 		.maxlen		= sizeof(unsigned int),
358 		.mode		= 0644,
359 		.proc_handler	= proc_dointvec_minmax,
360 		.extra1		= &zero,
361 		.extra2		= &one,
362 	},
363 #endif
364 	{
365 		.procname	= "sched_rt_period_us",
366 		.data		= &sysctl_sched_rt_period,
367 		.maxlen		= sizeof(unsigned int),
368 		.mode		= 0644,
369 		.proc_handler	= sched_rt_handler,
370 	},
371 	{
372 		.procname	= "sched_rt_runtime_us",
373 		.data		= &sysctl_sched_rt_runtime,
374 		.maxlen		= sizeof(int),
375 		.mode		= 0644,
376 		.proc_handler	= sched_rt_handler,
377 	},
378 	{
379 		.procname	= "sched_compat_yield",
380 		.data		= &sysctl_sched_compat_yield,
381 		.maxlen		= sizeof(unsigned int),
382 		.mode		= 0644,
383 		.proc_handler	= proc_dointvec,
384 	},
385 #ifdef CONFIG_PROVE_LOCKING
386 	{
387 		.procname	= "prove_locking",
388 		.data		= &prove_locking,
389 		.maxlen		= sizeof(int),
390 		.mode		= 0644,
391 		.proc_handler	= proc_dointvec,
392 	},
393 #endif
394 #ifdef CONFIG_LOCK_STAT
395 	{
396 		.procname	= "lock_stat",
397 		.data		= &lock_stat,
398 		.maxlen		= sizeof(int),
399 		.mode		= 0644,
400 		.proc_handler	= proc_dointvec,
401 	},
402 #endif
403 	{
404 		.procname	= "panic",
405 		.data		= &panic_timeout,
406 		.maxlen		= sizeof(int),
407 		.mode		= 0644,
408 		.proc_handler	= proc_dointvec,
409 	},
410 	{
411 		.procname	= "core_uses_pid",
412 		.data		= &core_uses_pid,
413 		.maxlen		= sizeof(int),
414 		.mode		= 0644,
415 		.proc_handler	= proc_dointvec,
416 	},
417 	{
418 		.procname	= "core_pattern",
419 		.data		= core_pattern,
420 		.maxlen		= CORENAME_MAX_SIZE,
421 		.mode		= 0644,
422 		.proc_handler	= proc_dostring,
423 	},
424 	{
425 		.procname	= "core_pipe_limit",
426 		.data		= &core_pipe_limit,
427 		.maxlen		= sizeof(unsigned int),
428 		.mode		= 0644,
429 		.proc_handler	= proc_dointvec,
430 	},
431 #ifdef CONFIG_PROC_SYSCTL
432 	{
433 		.procname	= "tainted",
434 		.maxlen 	= sizeof(long),
435 		.mode		= 0644,
436 		.proc_handler	= proc_taint,
437 	},
438 #endif
439 #ifdef CONFIG_LATENCYTOP
440 	{
441 		.procname	= "latencytop",
442 		.data		= &latencytop_enabled,
443 		.maxlen		= sizeof(int),
444 		.mode		= 0644,
445 		.proc_handler	= proc_dointvec,
446 	},
447 #endif
448 #ifdef CONFIG_BLK_DEV_INITRD
449 	{
450 		.procname	= "real-root-dev",
451 		.data		= &real_root_dev,
452 		.maxlen		= sizeof(int),
453 		.mode		= 0644,
454 		.proc_handler	= proc_dointvec,
455 	},
456 #endif
457 	{
458 		.procname	= "print-fatal-signals",
459 		.data		= &print_fatal_signals,
460 		.maxlen		= sizeof(int),
461 		.mode		= 0644,
462 		.proc_handler	= proc_dointvec,
463 	},
464 #ifdef CONFIG_SPARC
465 	{
466 		.procname	= "reboot-cmd",
467 		.data		= reboot_command,
468 		.maxlen		= 256,
469 		.mode		= 0644,
470 		.proc_handler	= proc_dostring,
471 	},
472 	{
473 		.procname	= "stop-a",
474 		.data		= &stop_a_enabled,
475 		.maxlen		= sizeof (int),
476 		.mode		= 0644,
477 		.proc_handler	= proc_dointvec,
478 	},
479 	{
480 		.procname	= "scons-poweroff",
481 		.data		= &scons_pwroff,
482 		.maxlen		= sizeof (int),
483 		.mode		= 0644,
484 		.proc_handler	= proc_dointvec,
485 	},
486 #endif
487 #ifdef CONFIG_SPARC64
488 	{
489 		.procname	= "tsb-ratio",
490 		.data		= &sysctl_tsb_ratio,
491 		.maxlen		= sizeof (int),
492 		.mode		= 0644,
493 		.proc_handler	= proc_dointvec,
494 	},
495 #endif
496 #ifdef __hppa__
497 	{
498 		.procname	= "soft-power",
499 		.data		= &pwrsw_enabled,
500 		.maxlen		= sizeof (int),
501 	 	.mode		= 0644,
502 		.proc_handler	= proc_dointvec,
503 	},
504 	{
505 		.procname	= "unaligned-trap",
506 		.data		= &unaligned_enabled,
507 		.maxlen		= sizeof (int),
508 		.mode		= 0644,
509 		.proc_handler	= proc_dointvec,
510 	},
511 #endif
512 	{
513 		.procname	= "ctrl-alt-del",
514 		.data		= &C_A_D,
515 		.maxlen		= sizeof(int),
516 		.mode		= 0644,
517 		.proc_handler	= proc_dointvec,
518 	},
519 #ifdef CONFIG_FUNCTION_TRACER
520 	{
521 		.procname	= "ftrace_enabled",
522 		.data		= &ftrace_enabled,
523 		.maxlen		= sizeof(int),
524 		.mode		= 0644,
525 		.proc_handler	= ftrace_enable_sysctl,
526 	},
527 #endif
528 #ifdef CONFIG_STACK_TRACER
529 	{
530 		.procname	= "stack_tracer_enabled",
531 		.data		= &stack_tracer_enabled,
532 		.maxlen		= sizeof(int),
533 		.mode		= 0644,
534 		.proc_handler	= stack_trace_sysctl,
535 	},
536 #endif
537 #ifdef CONFIG_TRACING
538 	{
539 		.procname	= "ftrace_dump_on_oops",
540 		.data		= &ftrace_dump_on_oops,
541 		.maxlen		= sizeof(int),
542 		.mode		= 0644,
543 		.proc_handler	= proc_dointvec,
544 	},
545 #endif
546 #ifdef CONFIG_MODULES
547 	{
548 		.procname	= "modprobe",
549 		.data		= &modprobe_path,
550 		.maxlen		= KMOD_PATH_LEN,
551 		.mode		= 0644,
552 		.proc_handler	= proc_dostring,
553 	},
554 	{
555 		.procname	= "modules_disabled",
556 		.data		= &modules_disabled,
557 		.maxlen		= sizeof(int),
558 		.mode		= 0644,
559 		/* only handle a transition from default "0" to "1" */
560 		.proc_handler	= proc_dointvec_minmax,
561 		.extra1		= &one,
562 		.extra2		= &one,
563 	},
564 #endif
565 #ifdef CONFIG_HOTPLUG
566 	{
567 		.procname	= "hotplug",
568 		.data		= &uevent_helper,
569 		.maxlen		= UEVENT_HELPER_PATH_LEN,
570 		.mode		= 0644,
571 		.proc_handler	= proc_dostring,
572 	},
573 #endif
574 #ifdef CONFIG_CHR_DEV_SG
575 	{
576 		.procname	= "sg-big-buff",
577 		.data		= &sg_big_buff,
578 		.maxlen		= sizeof (int),
579 		.mode		= 0444,
580 		.proc_handler	= proc_dointvec,
581 	},
582 #endif
583 #ifdef CONFIG_BSD_PROCESS_ACCT
584 	{
585 		.procname	= "acct",
586 		.data		= &acct_parm,
587 		.maxlen		= 3*sizeof(int),
588 		.mode		= 0644,
589 		.proc_handler	= proc_dointvec,
590 	},
591 #endif
592 #ifdef CONFIG_MAGIC_SYSRQ
593 	{
594 		.procname	= "sysrq",
595 		.data		= &__sysrq_enabled,
596 		.maxlen		= sizeof (int),
597 		.mode		= 0644,
598 		.proc_handler	= sysrq_sysctl_handler,
599 	},
600 #endif
601 #ifdef CONFIG_PROC_SYSCTL
602 	{
603 		.procname	= "cad_pid",
604 		.data		= NULL,
605 		.maxlen		= sizeof (int),
606 		.mode		= 0600,
607 		.proc_handler	= proc_do_cad_pid,
608 	},
609 #endif
610 	{
611 		.procname	= "threads-max",
612 		.data		= &max_threads,
613 		.maxlen		= sizeof(int),
614 		.mode		= 0644,
615 		.proc_handler	= proc_dointvec,
616 	},
617 	{
618 		.procname	= "random",
619 		.mode		= 0555,
620 		.child		= random_table,
621 	},
622 	{
623 		.procname	= "overflowuid",
624 		.data		= &overflowuid,
625 		.maxlen		= sizeof(int),
626 		.mode		= 0644,
627 		.proc_handler	= proc_dointvec_minmax,
628 		.extra1		= &minolduid,
629 		.extra2		= &maxolduid,
630 	},
631 	{
632 		.procname	= "overflowgid",
633 		.data		= &overflowgid,
634 		.maxlen		= sizeof(int),
635 		.mode		= 0644,
636 		.proc_handler	= proc_dointvec_minmax,
637 		.extra1		= &minolduid,
638 		.extra2		= &maxolduid,
639 	},
640 #ifdef CONFIG_S390
641 #ifdef CONFIG_MATHEMU
642 	{
643 		.procname	= "ieee_emulation_warnings",
644 		.data		= &sysctl_ieee_emulation_warnings,
645 		.maxlen		= sizeof(int),
646 		.mode		= 0644,
647 		.proc_handler	= proc_dointvec,
648 	},
649 #endif
650 	{
651 		.procname	= "userprocess_debug",
652 		.data		= &show_unhandled_signals,
653 		.maxlen		= sizeof(int),
654 		.mode		= 0644,
655 		.proc_handler	= proc_dointvec,
656 	},
657 #endif
658 	{
659 		.procname	= "pid_max",
660 		.data		= &pid_max,
661 		.maxlen		= sizeof (int),
662 		.mode		= 0644,
663 		.proc_handler	= proc_dointvec_minmax,
664 		.extra1		= &pid_max_min,
665 		.extra2		= &pid_max_max,
666 	},
667 	{
668 		.procname	= "panic_on_oops",
669 		.data		= &panic_on_oops,
670 		.maxlen		= sizeof(int),
671 		.mode		= 0644,
672 		.proc_handler	= proc_dointvec,
673 	},
674 #if defined CONFIG_PRINTK
675 	{
676 		.procname	= "printk",
677 		.data		= &console_loglevel,
678 		.maxlen		= 4*sizeof(int),
679 		.mode		= 0644,
680 		.proc_handler	= proc_dointvec,
681 	},
682 	{
683 		.procname	= "printk_ratelimit",
684 		.data		= &printk_ratelimit_state.interval,
685 		.maxlen		= sizeof(int),
686 		.mode		= 0644,
687 		.proc_handler	= proc_dointvec_jiffies,
688 	},
689 	{
690 		.procname	= "printk_ratelimit_burst",
691 		.data		= &printk_ratelimit_state.burst,
692 		.maxlen		= sizeof(int),
693 		.mode		= 0644,
694 		.proc_handler	= proc_dointvec,
695 	},
696 	{
697 		.procname	= "printk_delay",
698 		.data		= &printk_delay_msec,
699 		.maxlen		= sizeof(int),
700 		.mode		= 0644,
701 		.proc_handler	= proc_dointvec_minmax,
702 		.extra1		= &zero,
703 		.extra2		= &ten_thousand,
704 	},
705 	{
706 		.procname	= "dmesg_restrict",
707 		.data		= &dmesg_restrict,
708 		.maxlen		= sizeof(int),
709 		.mode		= 0644,
710 		.proc_handler	= proc_dointvec_minmax,
711 		.extra1		= &zero,
712 		.extra2		= &one,
713 	},
714 #endif
715 	{
716 		.procname	= "ngroups_max",
717 		.data		= &ngroups_max,
718 		.maxlen		= sizeof (int),
719 		.mode		= 0444,
720 		.proc_handler	= proc_dointvec,
721 	},
722 #if defined(CONFIG_LOCKUP_DETECTOR)
723 	{
724 		.procname       = "watchdog",
725 		.data           = &watchdog_enabled,
726 		.maxlen         = sizeof (int),
727 		.mode           = 0644,
728 		.proc_handler   = proc_dowatchdog_enabled,
729 	},
730 	{
731 		.procname	= "watchdog_thresh",
732 		.data		= &softlockup_thresh,
733 		.maxlen		= sizeof(int),
734 		.mode		= 0644,
735 		.proc_handler	= proc_dowatchdog_thresh,
736 		.extra1		= &neg_one,
737 		.extra2		= &sixty,
738 	},
739 	{
740 		.procname	= "softlockup_panic",
741 		.data		= &softlockup_panic,
742 		.maxlen		= sizeof(int),
743 		.mode		= 0644,
744 		.proc_handler	= proc_dointvec_minmax,
745 		.extra1		= &zero,
746 		.extra2		= &one,
747 	},
748 #endif
749 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
750 	{
751 		.procname       = "unknown_nmi_panic",
752 		.data           = &unknown_nmi_panic,
753 		.maxlen         = sizeof (int),
754 		.mode           = 0644,
755 		.proc_handler   = proc_dointvec,
756 	},
757 	{
758 		.procname       = "nmi_watchdog",
759 		.data           = &nmi_watchdog_enabled,
760 		.maxlen         = sizeof (int),
761 		.mode           = 0644,
762 		.proc_handler   = proc_nmi_enabled,
763 	},
764 #endif
765 #if defined(CONFIG_X86)
766 	{
767 		.procname	= "panic_on_unrecovered_nmi",
768 		.data		= &panic_on_unrecovered_nmi,
769 		.maxlen		= sizeof(int),
770 		.mode		= 0644,
771 		.proc_handler	= proc_dointvec,
772 	},
773 	{
774 		.procname	= "panic_on_io_nmi",
775 		.data		= &panic_on_io_nmi,
776 		.maxlen		= sizeof(int),
777 		.mode		= 0644,
778 		.proc_handler	= proc_dointvec,
779 	},
780 	{
781 		.procname	= "bootloader_type",
782 		.data		= &bootloader_type,
783 		.maxlen		= sizeof (int),
784 		.mode		= 0444,
785 		.proc_handler	= proc_dointvec,
786 	},
787 	{
788 		.procname	= "bootloader_version",
789 		.data		= &bootloader_version,
790 		.maxlen		= sizeof (int),
791 		.mode		= 0444,
792 		.proc_handler	= proc_dointvec,
793 	},
794 	{
795 		.procname	= "kstack_depth_to_print",
796 		.data		= &kstack_depth_to_print,
797 		.maxlen		= sizeof(int),
798 		.mode		= 0644,
799 		.proc_handler	= proc_dointvec,
800 	},
801 	{
802 		.procname	= "io_delay_type",
803 		.data		= &io_delay_type,
804 		.maxlen		= sizeof(int),
805 		.mode		= 0644,
806 		.proc_handler	= proc_dointvec,
807 	},
808 #endif
809 #if defined(CONFIG_MMU)
810 	{
811 		.procname	= "randomize_va_space",
812 		.data		= &randomize_va_space,
813 		.maxlen		= sizeof(int),
814 		.mode		= 0644,
815 		.proc_handler	= proc_dointvec,
816 	},
817 #endif
818 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
819 	{
820 		.procname	= "spin_retry",
821 		.data		= &spin_retry,
822 		.maxlen		= sizeof (int),
823 		.mode		= 0644,
824 		.proc_handler	= proc_dointvec,
825 	},
826 #endif
827 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
828 	{
829 		.procname	= "acpi_video_flags",
830 		.data		= &acpi_realmode_flags,
831 		.maxlen		= sizeof (unsigned long),
832 		.mode		= 0644,
833 		.proc_handler	= proc_doulongvec_minmax,
834 	},
835 #endif
836 #ifdef CONFIG_IA64
837 	{
838 		.procname	= "ignore-unaligned-usertrap",
839 		.data		= &no_unaligned_warning,
840 		.maxlen		= sizeof (int),
841 	 	.mode		= 0644,
842 		.proc_handler	= proc_dointvec,
843 	},
844 	{
845 		.procname	= "unaligned-dump-stack",
846 		.data		= &unaligned_dump_stack,
847 		.maxlen		= sizeof (int),
848 		.mode		= 0644,
849 		.proc_handler	= proc_dointvec,
850 	},
851 #endif
852 #ifdef CONFIG_DETECT_HUNG_TASK
853 	{
854 		.procname	= "hung_task_panic",
855 		.data		= &sysctl_hung_task_panic,
856 		.maxlen		= sizeof(int),
857 		.mode		= 0644,
858 		.proc_handler	= proc_dointvec_minmax,
859 		.extra1		= &zero,
860 		.extra2		= &one,
861 	},
862 	{
863 		.procname	= "hung_task_check_count",
864 		.data		= &sysctl_hung_task_check_count,
865 		.maxlen		= sizeof(unsigned long),
866 		.mode		= 0644,
867 		.proc_handler	= proc_doulongvec_minmax,
868 	},
869 	{
870 		.procname	= "hung_task_timeout_secs",
871 		.data		= &sysctl_hung_task_timeout_secs,
872 		.maxlen		= sizeof(unsigned long),
873 		.mode		= 0644,
874 		.proc_handler	= proc_dohung_task_timeout_secs,
875 	},
876 	{
877 		.procname	= "hung_task_warnings",
878 		.data		= &sysctl_hung_task_warnings,
879 		.maxlen		= sizeof(unsigned long),
880 		.mode		= 0644,
881 		.proc_handler	= proc_doulongvec_minmax,
882 	},
883 #endif
884 #ifdef CONFIG_COMPAT
885 	{
886 		.procname	= "compat-log",
887 		.data		= &compat_log,
888 		.maxlen		= sizeof (int),
889 	 	.mode		= 0644,
890 		.proc_handler	= proc_dointvec,
891 	},
892 #endif
893 #ifdef CONFIG_RT_MUTEXES
894 	{
895 		.procname	= "max_lock_depth",
896 		.data		= &max_lock_depth,
897 		.maxlen		= sizeof(int),
898 		.mode		= 0644,
899 		.proc_handler	= proc_dointvec,
900 	},
901 #endif
902 	{
903 		.procname	= "poweroff_cmd",
904 		.data		= &poweroff_cmd,
905 		.maxlen		= POWEROFF_CMD_PATH_LEN,
906 		.mode		= 0644,
907 		.proc_handler	= proc_dostring,
908 	},
909 #ifdef CONFIG_KEYS
910 	{
911 		.procname	= "keys",
912 		.mode		= 0555,
913 		.child		= key_sysctls,
914 	},
915 #endif
916 #ifdef CONFIG_RCU_TORTURE_TEST
917 	{
918 		.procname       = "rcutorture_runnable",
919 		.data           = &rcutorture_runnable,
920 		.maxlen         = sizeof(int),
921 		.mode           = 0644,
922 		.proc_handler	= proc_dointvec,
923 	},
924 #endif
925 #ifdef CONFIG_PERF_EVENTS
926 	{
927 		.procname	= "perf_event_paranoid",
928 		.data		= &sysctl_perf_event_paranoid,
929 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
930 		.mode		= 0644,
931 		.proc_handler	= proc_dointvec,
932 	},
933 	{
934 		.procname	= "perf_event_mlock_kb",
935 		.data		= &sysctl_perf_event_mlock,
936 		.maxlen		= sizeof(sysctl_perf_event_mlock),
937 		.mode		= 0644,
938 		.proc_handler	= proc_dointvec,
939 	},
940 	{
941 		.procname	= "perf_event_max_sample_rate",
942 		.data		= &sysctl_perf_event_sample_rate,
943 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
944 		.mode		= 0644,
945 		.proc_handler	= proc_dointvec,
946 	},
947 #endif
948 #ifdef CONFIG_KMEMCHECK
949 	{
950 		.procname	= "kmemcheck",
951 		.data		= &kmemcheck_enabled,
952 		.maxlen		= sizeof(int),
953 		.mode		= 0644,
954 		.proc_handler	= proc_dointvec,
955 	},
956 #endif
957 #ifdef CONFIG_BLOCK
958 	{
959 		.procname	= "blk_iopoll",
960 		.data		= &blk_iopoll_enabled,
961 		.maxlen		= sizeof(int),
962 		.mode		= 0644,
963 		.proc_handler	= proc_dointvec,
964 	},
965 #endif
966 /*
967  * NOTE: do not add new entries to this table unless you have read
968  * Documentation/sysctl/ctl_unnumbered.txt
969  */
970 	{ }
971 };
972 
973 static struct ctl_table vm_table[] = {
974 	{
975 		.procname	= "overcommit_memory",
976 		.data		= &sysctl_overcommit_memory,
977 		.maxlen		= sizeof(sysctl_overcommit_memory),
978 		.mode		= 0644,
979 		.proc_handler	= proc_dointvec,
980 	},
981 	{
982 		.procname	= "panic_on_oom",
983 		.data		= &sysctl_panic_on_oom,
984 		.maxlen		= sizeof(sysctl_panic_on_oom),
985 		.mode		= 0644,
986 		.proc_handler	= proc_dointvec,
987 	},
988 	{
989 		.procname	= "oom_kill_allocating_task",
990 		.data		= &sysctl_oom_kill_allocating_task,
991 		.maxlen		= sizeof(sysctl_oom_kill_allocating_task),
992 		.mode		= 0644,
993 		.proc_handler	= proc_dointvec,
994 	},
995 	{
996 		.procname	= "oom_dump_tasks",
997 		.data		= &sysctl_oom_dump_tasks,
998 		.maxlen		= sizeof(sysctl_oom_dump_tasks),
999 		.mode		= 0644,
1000 		.proc_handler	= proc_dointvec,
1001 	},
1002 	{
1003 		.procname	= "overcommit_ratio",
1004 		.data		= &sysctl_overcommit_ratio,
1005 		.maxlen		= sizeof(sysctl_overcommit_ratio),
1006 		.mode		= 0644,
1007 		.proc_handler	= proc_dointvec,
1008 	},
1009 	{
1010 		.procname	= "page-cluster",
1011 		.data		= &page_cluster,
1012 		.maxlen		= sizeof(int),
1013 		.mode		= 0644,
1014 		.proc_handler	= proc_dointvec,
1015 	},
1016 	{
1017 		.procname	= "dirty_background_ratio",
1018 		.data		= &dirty_background_ratio,
1019 		.maxlen		= sizeof(dirty_background_ratio),
1020 		.mode		= 0644,
1021 		.proc_handler	= dirty_background_ratio_handler,
1022 		.extra1		= &zero,
1023 		.extra2		= &one_hundred,
1024 	},
1025 	{
1026 		.procname	= "dirty_background_bytes",
1027 		.data		= &dirty_background_bytes,
1028 		.maxlen		= sizeof(dirty_background_bytes),
1029 		.mode		= 0644,
1030 		.proc_handler	= dirty_background_bytes_handler,
1031 		.extra1		= &one_ul,
1032 	},
1033 	{
1034 		.procname	= "dirty_ratio",
1035 		.data		= &vm_dirty_ratio,
1036 		.maxlen		= sizeof(vm_dirty_ratio),
1037 		.mode		= 0644,
1038 		.proc_handler	= dirty_ratio_handler,
1039 		.extra1		= &zero,
1040 		.extra2		= &one_hundred,
1041 	},
1042 	{
1043 		.procname	= "dirty_bytes",
1044 		.data		= &vm_dirty_bytes,
1045 		.maxlen		= sizeof(vm_dirty_bytes),
1046 		.mode		= 0644,
1047 		.proc_handler	= dirty_bytes_handler,
1048 		.extra1		= &dirty_bytes_min,
1049 	},
1050 	{
1051 		.procname	= "dirty_writeback_centisecs",
1052 		.data		= &dirty_writeback_interval,
1053 		.maxlen		= sizeof(dirty_writeback_interval),
1054 		.mode		= 0644,
1055 		.proc_handler	= dirty_writeback_centisecs_handler,
1056 	},
1057 	{
1058 		.procname	= "dirty_expire_centisecs",
1059 		.data		= &dirty_expire_interval,
1060 		.maxlen		= sizeof(dirty_expire_interval),
1061 		.mode		= 0644,
1062 		.proc_handler	= proc_dointvec,
1063 	},
1064 	{
1065 		.procname	= "nr_pdflush_threads",
1066 		.data		= &nr_pdflush_threads,
1067 		.maxlen		= sizeof nr_pdflush_threads,
1068 		.mode		= 0444 /* read-only*/,
1069 		.proc_handler	= proc_dointvec,
1070 	},
1071 	{
1072 		.procname	= "swappiness",
1073 		.data		= &vm_swappiness,
1074 		.maxlen		= sizeof(vm_swappiness),
1075 		.mode		= 0644,
1076 		.proc_handler	= proc_dointvec_minmax,
1077 		.extra1		= &zero,
1078 		.extra2		= &one_hundred,
1079 	},
1080 #ifdef CONFIG_HUGETLB_PAGE
1081 	{
1082 		.procname	= "nr_hugepages",
1083 		.data		= NULL,
1084 		.maxlen		= sizeof(unsigned long),
1085 		.mode		= 0644,
1086 		.proc_handler	= hugetlb_sysctl_handler,
1087 		.extra1		= (void *)&hugetlb_zero,
1088 		.extra2		= (void *)&hugetlb_infinity,
1089 	},
1090 #ifdef CONFIG_NUMA
1091 	{
1092 		.procname       = "nr_hugepages_mempolicy",
1093 		.data           = NULL,
1094 		.maxlen         = sizeof(unsigned long),
1095 		.mode           = 0644,
1096 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
1097 		.extra1		= (void *)&hugetlb_zero,
1098 		.extra2		= (void *)&hugetlb_infinity,
1099 	},
1100 #endif
1101 	 {
1102 		.procname	= "hugetlb_shm_group",
1103 		.data		= &sysctl_hugetlb_shm_group,
1104 		.maxlen		= sizeof(gid_t),
1105 		.mode		= 0644,
1106 		.proc_handler	= proc_dointvec,
1107 	 },
1108 	 {
1109 		.procname	= "hugepages_treat_as_movable",
1110 		.data		= &hugepages_treat_as_movable,
1111 		.maxlen		= sizeof(int),
1112 		.mode		= 0644,
1113 		.proc_handler	= hugetlb_treat_movable_handler,
1114 	},
1115 	{
1116 		.procname	= "nr_overcommit_hugepages",
1117 		.data		= NULL,
1118 		.maxlen		= sizeof(unsigned long),
1119 		.mode		= 0644,
1120 		.proc_handler	= hugetlb_overcommit_handler,
1121 		.extra1		= (void *)&hugetlb_zero,
1122 		.extra2		= (void *)&hugetlb_infinity,
1123 	},
1124 #endif
1125 	{
1126 		.procname	= "lowmem_reserve_ratio",
1127 		.data		= &sysctl_lowmem_reserve_ratio,
1128 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
1129 		.mode		= 0644,
1130 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
1131 	},
1132 	{
1133 		.procname	= "drop_caches",
1134 		.data		= &sysctl_drop_caches,
1135 		.maxlen		= sizeof(int),
1136 		.mode		= 0644,
1137 		.proc_handler	= drop_caches_sysctl_handler,
1138 	},
1139 #ifdef CONFIG_COMPACTION
1140 	{
1141 		.procname	= "compact_memory",
1142 		.data		= &sysctl_compact_memory,
1143 		.maxlen		= sizeof(int),
1144 		.mode		= 0200,
1145 		.proc_handler	= sysctl_compaction_handler,
1146 	},
1147 	{
1148 		.procname	= "extfrag_threshold",
1149 		.data		= &sysctl_extfrag_threshold,
1150 		.maxlen		= sizeof(int),
1151 		.mode		= 0644,
1152 		.proc_handler	= sysctl_extfrag_handler,
1153 		.extra1		= &min_extfrag_threshold,
1154 		.extra2		= &max_extfrag_threshold,
1155 	},
1156 
1157 #endif /* CONFIG_COMPACTION */
1158 	{
1159 		.procname	= "min_free_kbytes",
1160 		.data		= &min_free_kbytes,
1161 		.maxlen		= sizeof(min_free_kbytes),
1162 		.mode		= 0644,
1163 		.proc_handler	= min_free_kbytes_sysctl_handler,
1164 		.extra1		= &zero,
1165 	},
1166 	{
1167 		.procname	= "percpu_pagelist_fraction",
1168 		.data		= &percpu_pagelist_fraction,
1169 		.maxlen		= sizeof(percpu_pagelist_fraction),
1170 		.mode		= 0644,
1171 		.proc_handler	= percpu_pagelist_fraction_sysctl_handler,
1172 		.extra1		= &min_percpu_pagelist_fract,
1173 	},
1174 #ifdef CONFIG_MMU
1175 	{
1176 		.procname	= "max_map_count",
1177 		.data		= &sysctl_max_map_count,
1178 		.maxlen		= sizeof(sysctl_max_map_count),
1179 		.mode		= 0644,
1180 		.proc_handler	= proc_dointvec_minmax,
1181 		.extra1		= &zero,
1182 	},
1183 #else
1184 	{
1185 		.procname	= "nr_trim_pages",
1186 		.data		= &sysctl_nr_trim_pages,
1187 		.maxlen		= sizeof(sysctl_nr_trim_pages),
1188 		.mode		= 0644,
1189 		.proc_handler	= proc_dointvec_minmax,
1190 		.extra1		= &zero,
1191 	},
1192 #endif
1193 	{
1194 		.procname	= "laptop_mode",
1195 		.data		= &laptop_mode,
1196 		.maxlen		= sizeof(laptop_mode),
1197 		.mode		= 0644,
1198 		.proc_handler	= proc_dointvec_jiffies,
1199 	},
1200 	{
1201 		.procname	= "block_dump",
1202 		.data		= &block_dump,
1203 		.maxlen		= sizeof(block_dump),
1204 		.mode		= 0644,
1205 		.proc_handler	= proc_dointvec,
1206 		.extra1		= &zero,
1207 	},
1208 	{
1209 		.procname	= "vfs_cache_pressure",
1210 		.data		= &sysctl_vfs_cache_pressure,
1211 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
1212 		.mode		= 0644,
1213 		.proc_handler	= proc_dointvec,
1214 		.extra1		= &zero,
1215 	},
1216 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
1217 	{
1218 		.procname	= "legacy_va_layout",
1219 		.data		= &sysctl_legacy_va_layout,
1220 		.maxlen		= sizeof(sysctl_legacy_va_layout),
1221 		.mode		= 0644,
1222 		.proc_handler	= proc_dointvec,
1223 		.extra1		= &zero,
1224 	},
1225 #endif
1226 #ifdef CONFIG_NUMA
1227 	{
1228 		.procname	= "zone_reclaim_mode",
1229 		.data		= &zone_reclaim_mode,
1230 		.maxlen		= sizeof(zone_reclaim_mode),
1231 		.mode		= 0644,
1232 		.proc_handler	= proc_dointvec,
1233 		.extra1		= &zero,
1234 	},
1235 	{
1236 		.procname	= "min_unmapped_ratio",
1237 		.data		= &sysctl_min_unmapped_ratio,
1238 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
1239 		.mode		= 0644,
1240 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
1241 		.extra1		= &zero,
1242 		.extra2		= &one_hundred,
1243 	},
1244 	{
1245 		.procname	= "min_slab_ratio",
1246 		.data		= &sysctl_min_slab_ratio,
1247 		.maxlen		= sizeof(sysctl_min_slab_ratio),
1248 		.mode		= 0644,
1249 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
1250 		.extra1		= &zero,
1251 		.extra2		= &one_hundred,
1252 	},
1253 #endif
1254 #ifdef CONFIG_SMP
1255 	{
1256 		.procname	= "stat_interval",
1257 		.data		= &sysctl_stat_interval,
1258 		.maxlen		= sizeof(sysctl_stat_interval),
1259 		.mode		= 0644,
1260 		.proc_handler	= proc_dointvec_jiffies,
1261 	},
1262 #endif
1263 #ifdef CONFIG_MMU
1264 	{
1265 		.procname	= "mmap_min_addr",
1266 		.data		= &dac_mmap_min_addr,
1267 		.maxlen		= sizeof(unsigned long),
1268 		.mode		= 0644,
1269 		.proc_handler	= mmap_min_addr_handler,
1270 	},
1271 #endif
1272 #ifdef CONFIG_NUMA
1273 	{
1274 		.procname	= "numa_zonelist_order",
1275 		.data		= &numa_zonelist_order,
1276 		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
1277 		.mode		= 0644,
1278 		.proc_handler	= numa_zonelist_order_handler,
1279 	},
1280 #endif
1281 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
1282    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
1283 	{
1284 		.procname	= "vdso_enabled",
1285 		.data		= &vdso_enabled,
1286 		.maxlen		= sizeof(vdso_enabled),
1287 		.mode		= 0644,
1288 		.proc_handler	= proc_dointvec,
1289 		.extra1		= &zero,
1290 	},
1291 #endif
1292 #ifdef CONFIG_HIGHMEM
1293 	{
1294 		.procname	= "highmem_is_dirtyable",
1295 		.data		= &vm_highmem_is_dirtyable,
1296 		.maxlen		= sizeof(vm_highmem_is_dirtyable),
1297 		.mode		= 0644,
1298 		.proc_handler	= proc_dointvec_minmax,
1299 		.extra1		= &zero,
1300 		.extra2		= &one,
1301 	},
1302 #endif
1303 	{
1304 		.procname	= "scan_unevictable_pages",
1305 		.data		= &scan_unevictable_pages,
1306 		.maxlen		= sizeof(scan_unevictable_pages),
1307 		.mode		= 0644,
1308 		.proc_handler	= scan_unevictable_handler,
1309 	},
1310 #ifdef CONFIG_MEMORY_FAILURE
1311 	{
1312 		.procname	= "memory_failure_early_kill",
1313 		.data		= &sysctl_memory_failure_early_kill,
1314 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
1315 		.mode		= 0644,
1316 		.proc_handler	= proc_dointvec_minmax,
1317 		.extra1		= &zero,
1318 		.extra2		= &one,
1319 	},
1320 	{
1321 		.procname	= "memory_failure_recovery",
1322 		.data		= &sysctl_memory_failure_recovery,
1323 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
1324 		.mode		= 0644,
1325 		.proc_handler	= proc_dointvec_minmax,
1326 		.extra1		= &zero,
1327 		.extra2		= &one,
1328 	},
1329 #endif
1330 
1331 /*
1332  * NOTE: do not add new entries to this table unless you have read
1333  * Documentation/sysctl/ctl_unnumbered.txt
1334  */
1335 	{ }
1336 };
1337 
1338 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1339 static struct ctl_table binfmt_misc_table[] = {
1340 	{ }
1341 };
1342 #endif
1343 
1344 static struct ctl_table fs_table[] = {
1345 	{
1346 		.procname	= "inode-nr",
1347 		.data		= &inodes_stat,
1348 		.maxlen		= 2*sizeof(int),
1349 		.mode		= 0444,
1350 		.proc_handler	= proc_nr_inodes,
1351 	},
1352 	{
1353 		.procname	= "inode-state",
1354 		.data		= &inodes_stat,
1355 		.maxlen		= 7*sizeof(int),
1356 		.mode		= 0444,
1357 		.proc_handler	= proc_nr_inodes,
1358 	},
1359 	{
1360 		.procname	= "file-nr",
1361 		.data		= &files_stat,
1362 		.maxlen		= sizeof(files_stat),
1363 		.mode		= 0444,
1364 		.proc_handler	= proc_nr_files,
1365 	},
1366 	{
1367 		.procname	= "file-max",
1368 		.data		= &files_stat.max_files,
1369 		.maxlen		= sizeof(files_stat.max_files),
1370 		.mode		= 0644,
1371 		.proc_handler	= proc_doulongvec_minmax,
1372 	},
1373 	{
1374 		.procname	= "nr_open",
1375 		.data		= &sysctl_nr_open,
1376 		.maxlen		= sizeof(int),
1377 		.mode		= 0644,
1378 		.proc_handler	= proc_dointvec_minmax,
1379 		.extra1		= &sysctl_nr_open_min,
1380 		.extra2		= &sysctl_nr_open_max,
1381 	},
1382 	{
1383 		.procname	= "dentry-state",
1384 		.data		= &dentry_stat,
1385 		.maxlen		= 6*sizeof(int),
1386 		.mode		= 0444,
1387 		.proc_handler	= proc_nr_dentry,
1388 	},
1389 	{
1390 		.procname	= "overflowuid",
1391 		.data		= &fs_overflowuid,
1392 		.maxlen		= sizeof(int),
1393 		.mode		= 0644,
1394 		.proc_handler	= proc_dointvec_minmax,
1395 		.extra1		= &minolduid,
1396 		.extra2		= &maxolduid,
1397 	},
1398 	{
1399 		.procname	= "overflowgid",
1400 		.data		= &fs_overflowgid,
1401 		.maxlen		= sizeof(int),
1402 		.mode		= 0644,
1403 		.proc_handler	= proc_dointvec_minmax,
1404 		.extra1		= &minolduid,
1405 		.extra2		= &maxolduid,
1406 	},
1407 #ifdef CONFIG_FILE_LOCKING
1408 	{
1409 		.procname	= "leases-enable",
1410 		.data		= &leases_enable,
1411 		.maxlen		= sizeof(int),
1412 		.mode		= 0644,
1413 		.proc_handler	= proc_dointvec,
1414 	},
1415 #endif
1416 #ifdef CONFIG_DNOTIFY
1417 	{
1418 		.procname	= "dir-notify-enable",
1419 		.data		= &dir_notify_enable,
1420 		.maxlen		= sizeof(int),
1421 		.mode		= 0644,
1422 		.proc_handler	= proc_dointvec,
1423 	},
1424 #endif
1425 #ifdef CONFIG_MMU
1426 #ifdef CONFIG_FILE_LOCKING
1427 	{
1428 		.procname	= "lease-break-time",
1429 		.data		= &lease_break_time,
1430 		.maxlen		= sizeof(int),
1431 		.mode		= 0644,
1432 		.proc_handler	= proc_dointvec,
1433 	},
1434 #endif
1435 #ifdef CONFIG_AIO
1436 	{
1437 		.procname	= "aio-nr",
1438 		.data		= &aio_nr,
1439 		.maxlen		= sizeof(aio_nr),
1440 		.mode		= 0444,
1441 		.proc_handler	= proc_doulongvec_minmax,
1442 	},
1443 	{
1444 		.procname	= "aio-max-nr",
1445 		.data		= &aio_max_nr,
1446 		.maxlen		= sizeof(aio_max_nr),
1447 		.mode		= 0644,
1448 		.proc_handler	= proc_doulongvec_minmax,
1449 	},
1450 #endif /* CONFIG_AIO */
1451 #ifdef CONFIG_INOTIFY_USER
1452 	{
1453 		.procname	= "inotify",
1454 		.mode		= 0555,
1455 		.child		= inotify_table,
1456 	},
1457 #endif
1458 #ifdef CONFIG_EPOLL
1459 	{
1460 		.procname	= "epoll",
1461 		.mode		= 0555,
1462 		.child		= epoll_table,
1463 	},
1464 #endif
1465 #endif
1466 	{
1467 		.procname	= "suid_dumpable",
1468 		.data		= &suid_dumpable,
1469 		.maxlen		= sizeof(int),
1470 		.mode		= 0644,
1471 		.proc_handler	= proc_dointvec_minmax,
1472 		.extra1		= &zero,
1473 		.extra2		= &two,
1474 	},
1475 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1476 	{
1477 		.procname	= "binfmt_misc",
1478 		.mode		= 0555,
1479 		.child		= binfmt_misc_table,
1480 	},
1481 #endif
1482 	{
1483 		.procname	= "pipe-max-size",
1484 		.data		= &pipe_max_size,
1485 		.maxlen		= sizeof(int),
1486 		.mode		= 0644,
1487 		.proc_handler	= &pipe_proc_fn,
1488 		.extra1		= &pipe_min_size,
1489 	},
1490 /*
1491  * NOTE: do not add new entries to this table unless you have read
1492  * Documentation/sysctl/ctl_unnumbered.txt
1493  */
1494 	{ }
1495 };
1496 
1497 static struct ctl_table debug_table[] = {
1498 #if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_SPARC) || \
1499     defined(CONFIG_S390)
1500 	{
1501 		.procname	= "exception-trace",
1502 		.data		= &show_unhandled_signals,
1503 		.maxlen		= sizeof(int),
1504 		.mode		= 0644,
1505 		.proc_handler	= proc_dointvec
1506 	},
1507 #endif
1508 #if defined(CONFIG_OPTPROBES)
1509 	{
1510 		.procname	= "kprobes-optimization",
1511 		.data		= &sysctl_kprobes_optimization,
1512 		.maxlen		= sizeof(int),
1513 		.mode		= 0644,
1514 		.proc_handler	= proc_kprobes_optimization_handler,
1515 		.extra1		= &zero,
1516 		.extra2		= &one,
1517 	},
1518 #endif
1519 	{ }
1520 };
1521 
1522 static struct ctl_table dev_table[] = {
1523 	{ }
1524 };
1525 
1526 static DEFINE_SPINLOCK(sysctl_lock);
1527 
1528 /* called under sysctl_lock */
1529 static int use_table(struct ctl_table_header *p)
1530 {
1531 	if (unlikely(p->unregistering))
1532 		return 0;
1533 	p->used++;
1534 	return 1;
1535 }
1536 
1537 /* called under sysctl_lock */
1538 static void unuse_table(struct ctl_table_header *p)
1539 {
1540 	if (!--p->used)
1541 		if (unlikely(p->unregistering))
1542 			complete(p->unregistering);
1543 }
1544 
1545 /* called under sysctl_lock, will reacquire if has to wait */
1546 static void start_unregistering(struct ctl_table_header *p)
1547 {
1548 	/*
1549 	 * if p->used is 0, nobody will ever touch that entry again;
1550 	 * we'll eliminate all paths to it before dropping sysctl_lock
1551 	 */
1552 	if (unlikely(p->used)) {
1553 		struct completion wait;
1554 		init_completion(&wait);
1555 		p->unregistering = &wait;
1556 		spin_unlock(&sysctl_lock);
1557 		wait_for_completion(&wait);
1558 		spin_lock(&sysctl_lock);
1559 	} else {
1560 		/* anything non-NULL; we'll never dereference it */
1561 		p->unregistering = ERR_PTR(-EINVAL);
1562 	}
1563 	/*
1564 	 * do not remove from the list until nobody holds it; walking the
1565 	 * list in do_sysctl() relies on that.
1566 	 */
1567 	list_del_init(&p->ctl_entry);
1568 }
1569 
1570 void sysctl_head_get(struct ctl_table_header *head)
1571 {
1572 	spin_lock(&sysctl_lock);
1573 	head->count++;
1574 	spin_unlock(&sysctl_lock);
1575 }
1576 
1577 void sysctl_head_put(struct ctl_table_header *head)
1578 {
1579 	spin_lock(&sysctl_lock);
1580 	if (!--head->count)
1581 		kfree(head);
1582 	spin_unlock(&sysctl_lock);
1583 }
1584 
1585 struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
1586 {
1587 	if (!head)
1588 		BUG();
1589 	spin_lock(&sysctl_lock);
1590 	if (!use_table(head))
1591 		head = ERR_PTR(-ENOENT);
1592 	spin_unlock(&sysctl_lock);
1593 	return head;
1594 }
1595 
1596 void sysctl_head_finish(struct ctl_table_header *head)
1597 {
1598 	if (!head)
1599 		return;
1600 	spin_lock(&sysctl_lock);
1601 	unuse_table(head);
1602 	spin_unlock(&sysctl_lock);
1603 }
1604 
1605 static struct ctl_table_set *
1606 lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
1607 {
1608 	struct ctl_table_set *set = &root->default_set;
1609 	if (root->lookup)
1610 		set = root->lookup(root, namespaces);
1611 	return set;
1612 }
1613 
1614 static struct list_head *
1615 lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
1616 {
1617 	struct ctl_table_set *set = lookup_header_set(root, namespaces);
1618 	return &set->list;
1619 }
1620 
1621 struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
1622 					    struct ctl_table_header *prev)
1623 {
1624 	struct ctl_table_root *root;
1625 	struct list_head *header_list;
1626 	struct ctl_table_header *head;
1627 	struct list_head *tmp;
1628 
1629 	spin_lock(&sysctl_lock);
1630 	if (prev) {
1631 		head = prev;
1632 		tmp = &prev->ctl_entry;
1633 		unuse_table(prev);
1634 		goto next;
1635 	}
1636 	tmp = &root_table_header.ctl_entry;
1637 	for (;;) {
1638 		head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1639 
1640 		if (!use_table(head))
1641 			goto next;
1642 		spin_unlock(&sysctl_lock);
1643 		return head;
1644 	next:
1645 		root = head->root;
1646 		tmp = tmp->next;
1647 		header_list = lookup_header_list(root, namespaces);
1648 		if (tmp != header_list)
1649 			continue;
1650 
1651 		do {
1652 			root = list_entry(root->root_list.next,
1653 					struct ctl_table_root, root_list);
1654 			if (root == &sysctl_table_root)
1655 				goto out;
1656 			header_list = lookup_header_list(root, namespaces);
1657 		} while (list_empty(header_list));
1658 		tmp = header_list->next;
1659 	}
1660 out:
1661 	spin_unlock(&sysctl_lock);
1662 	return NULL;
1663 }
1664 
1665 struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1666 {
1667 	return __sysctl_head_next(current->nsproxy, prev);
1668 }
1669 
1670 void register_sysctl_root(struct ctl_table_root *root)
1671 {
1672 	spin_lock(&sysctl_lock);
1673 	list_add_tail(&root->root_list, &sysctl_table_root.root_list);
1674 	spin_unlock(&sysctl_lock);
1675 }
1676 
1677 /*
1678  * sysctl_perm does NOT grant the superuser all rights automatically, because
1679  * some sysctl variables are readonly even to root.
1680  */
1681 
1682 static int test_perm(int mode, int op)
1683 {
1684 	if (!current_euid())
1685 		mode >>= 6;
1686 	else if (in_egroup_p(0))
1687 		mode >>= 3;
1688 	if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
1689 		return 0;
1690 	return -EACCES;
1691 }
1692 
1693 int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
1694 {
1695 	int error;
1696 	int mode;
1697 
1698 	error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
1699 	if (error)
1700 		return error;
1701 
1702 	if (root->permissions)
1703 		mode = root->permissions(root, current->nsproxy, table);
1704 	else
1705 		mode = table->mode;
1706 
1707 	return test_perm(mode, op);
1708 }
1709 
1710 static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1711 {
1712 	for (; table->procname; table++) {
1713 		table->parent = parent;
1714 		if (table->child)
1715 			sysctl_set_parent(table, table->child);
1716 	}
1717 }
1718 
1719 static __init int sysctl_init(void)
1720 {
1721 	sysctl_set_parent(NULL, root_table);
1722 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1723 	sysctl_check_table(current->nsproxy, root_table);
1724 #endif
1725 	return 0;
1726 }
1727 
1728 core_initcall(sysctl_init);
1729 
1730 static struct ctl_table *is_branch_in(struct ctl_table *branch,
1731 				      struct ctl_table *table)
1732 {
1733 	struct ctl_table *p;
1734 	const char *s = branch->procname;
1735 
1736 	/* branch should have named subdirectory as its first element */
1737 	if (!s || !branch->child)
1738 		return NULL;
1739 
1740 	/* ... and nothing else */
1741 	if (branch[1].procname)
1742 		return NULL;
1743 
1744 	/* table should contain subdirectory with the same name */
1745 	for (p = table; p->procname; p++) {
1746 		if (!p->child)
1747 			continue;
1748 		if (p->procname && strcmp(p->procname, s) == 0)
1749 			return p;
1750 	}
1751 	return NULL;
1752 }
1753 
1754 /* see if attaching q to p would be an improvement */
1755 static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
1756 {
1757 	struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
1758 	struct ctl_table *next;
1759 	int is_better = 0;
1760 	int not_in_parent = !p->attached_by;
1761 
1762 	while ((next = is_branch_in(by, to)) != NULL) {
1763 		if (by == q->attached_by)
1764 			is_better = 1;
1765 		if (to == p->attached_by)
1766 			not_in_parent = 1;
1767 		by = by->child;
1768 		to = next->child;
1769 	}
1770 
1771 	if (is_better && not_in_parent) {
1772 		q->attached_by = by;
1773 		q->attached_to = to;
1774 		q->parent = p;
1775 	}
1776 }
1777 
1778 /**
1779  * __register_sysctl_paths - register a sysctl hierarchy
1780  * @root: List of sysctl headers to register on
1781  * @namespaces: Data to compute which lists of sysctl entries are visible
1782  * @path: The path to the directory the sysctl table is in.
1783  * @table: the top-level table structure
1784  *
1785  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1786  * array. A completely 0 filled entry terminates the table.
1787  *
1788  * The members of the &struct ctl_table structure are used as follows:
1789  *
1790  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1791  *            enter a sysctl file
1792  *
1793  * data - a pointer to data for use by proc_handler
1794  *
1795  * maxlen - the maximum size in bytes of the data
1796  *
1797  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1798  *
1799  * child - a pointer to the child sysctl table if this entry is a directory, or
1800  *         %NULL.
1801  *
1802  * proc_handler - the text handler routine (described below)
1803  *
1804  * de - for internal use by the sysctl routines
1805  *
1806  * extra1, extra2 - extra pointers usable by the proc handler routines
1807  *
1808  * Leaf nodes in the sysctl tree will be represented by a single file
1809  * under /proc; non-leaf nodes will be represented by directories.
1810  *
1811  * sysctl(2) can automatically manage read and write requests through
1812  * the sysctl table.  The data and maxlen fields of the ctl_table
1813  * struct enable minimal validation of the values being written to be
1814  * performed, and the mode field allows minimal authentication.
1815  *
1816  * There must be a proc_handler routine for any terminal nodes
1817  * mirrored under /proc/sys (non-terminals are handled by a built-in
1818  * directory handler).  Several default handlers are available to
1819  * cover common cases -
1820  *
1821  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1822  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1823  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1824  *
1825  * It is the handler's job to read the input buffer from user memory
1826  * and process it. The handler should return 0 on success.
1827  *
1828  * This routine returns %NULL on a failure to register, and a pointer
1829  * to the table header on success.
1830  */
1831 struct ctl_table_header *__register_sysctl_paths(
1832 	struct ctl_table_root *root,
1833 	struct nsproxy *namespaces,
1834 	const struct ctl_path *path, struct ctl_table *table)
1835 {
1836 	struct ctl_table_header *header;
1837 	struct ctl_table *new, **prevp;
1838 	unsigned int n, npath;
1839 	struct ctl_table_set *set;
1840 
1841 	/* Count the path components */
1842 	for (npath = 0; path[npath].procname; ++npath)
1843 		;
1844 
1845 	/*
1846 	 * For each path component, allocate a 2-element ctl_table array.
1847 	 * The first array element will be filled with the sysctl entry
1848 	 * for this, the second will be the sentinel (procname == 0).
1849 	 *
1850 	 * We allocate everything in one go so that we don't have to
1851 	 * worry about freeing additional memory in unregister_sysctl_table.
1852 	 */
1853 	header = kzalloc(sizeof(struct ctl_table_header) +
1854 			 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
1855 	if (!header)
1856 		return NULL;
1857 
1858 	new = (struct ctl_table *) (header + 1);
1859 
1860 	/* Now connect the dots */
1861 	prevp = &header->ctl_table;
1862 	for (n = 0; n < npath; ++n, ++path) {
1863 		/* Copy the procname */
1864 		new->procname = path->procname;
1865 		new->mode     = 0555;
1866 
1867 		*prevp = new;
1868 		prevp = &new->child;
1869 
1870 		new += 2;
1871 	}
1872 	*prevp = table;
1873 	header->ctl_table_arg = table;
1874 
1875 	INIT_LIST_HEAD(&header->ctl_entry);
1876 	header->used = 0;
1877 	header->unregistering = NULL;
1878 	header->root = root;
1879 	sysctl_set_parent(NULL, header->ctl_table);
1880 	header->count = 1;
1881 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1882 	if (sysctl_check_table(namespaces, header->ctl_table)) {
1883 		kfree(header);
1884 		return NULL;
1885 	}
1886 #endif
1887 	spin_lock(&sysctl_lock);
1888 	header->set = lookup_header_set(root, namespaces);
1889 	header->attached_by = header->ctl_table;
1890 	header->attached_to = root_table;
1891 	header->parent = &root_table_header;
1892 	for (set = header->set; set; set = set->parent) {
1893 		struct ctl_table_header *p;
1894 		list_for_each_entry(p, &set->list, ctl_entry) {
1895 			if (p->unregistering)
1896 				continue;
1897 			try_attach(p, header);
1898 		}
1899 	}
1900 	header->parent->count++;
1901 	list_add_tail(&header->ctl_entry, &header->set->list);
1902 	spin_unlock(&sysctl_lock);
1903 
1904 	return header;
1905 }
1906 
1907 /**
1908  * register_sysctl_table_path - register a sysctl table hierarchy
1909  * @path: The path to the directory the sysctl table is in.
1910  * @table: the top-level table structure
1911  *
1912  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1913  * array. A completely 0 filled entry terminates the table.
1914  *
1915  * See __register_sysctl_paths for more details.
1916  */
1917 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1918 						struct ctl_table *table)
1919 {
1920 	return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1921 					path, table);
1922 }
1923 
1924 /**
1925  * register_sysctl_table - register a sysctl table hierarchy
1926  * @table: the top-level table structure
1927  *
1928  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1929  * array. A completely 0 filled entry terminates the table.
1930  *
1931  * See register_sysctl_paths for more details.
1932  */
1933 struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1934 {
1935 	static const struct ctl_path null_path[] = { {} };
1936 
1937 	return register_sysctl_paths(null_path, table);
1938 }
1939 
1940 /**
1941  * unregister_sysctl_table - unregister a sysctl table hierarchy
1942  * @header: the header returned from register_sysctl_table
1943  *
1944  * Unregisters the sysctl table and all children. proc entries may not
1945  * actually be removed until they are no longer used by anyone.
1946  */
1947 void unregister_sysctl_table(struct ctl_table_header * header)
1948 {
1949 	might_sleep();
1950 
1951 	if (header == NULL)
1952 		return;
1953 
1954 	spin_lock(&sysctl_lock);
1955 	start_unregistering(header);
1956 	if (!--header->parent->count) {
1957 		WARN_ON(1);
1958 		kfree(header->parent);
1959 	}
1960 	if (!--header->count)
1961 		kfree(header);
1962 	spin_unlock(&sysctl_lock);
1963 }
1964 
1965 int sysctl_is_seen(struct ctl_table_header *p)
1966 {
1967 	struct ctl_table_set *set = p->set;
1968 	int res;
1969 	spin_lock(&sysctl_lock);
1970 	if (p->unregistering)
1971 		res = 0;
1972 	else if (!set->is_seen)
1973 		res = 1;
1974 	else
1975 		res = set->is_seen(set);
1976 	spin_unlock(&sysctl_lock);
1977 	return res;
1978 }
1979 
1980 void setup_sysctl_set(struct ctl_table_set *p,
1981 	struct ctl_table_set *parent,
1982 	int (*is_seen)(struct ctl_table_set *))
1983 {
1984 	INIT_LIST_HEAD(&p->list);
1985 	p->parent = parent ? parent : &sysctl_table_root.default_set;
1986 	p->is_seen = is_seen;
1987 }
1988 
1989 #else /* !CONFIG_SYSCTL */
1990 struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
1991 {
1992 	return NULL;
1993 }
1994 
1995 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1996 						    struct ctl_table *table)
1997 {
1998 	return NULL;
1999 }
2000 
2001 void unregister_sysctl_table(struct ctl_table_header * table)
2002 {
2003 }
2004 
2005 void setup_sysctl_set(struct ctl_table_set *p,
2006 	struct ctl_table_set *parent,
2007 	int (*is_seen)(struct ctl_table_set *))
2008 {
2009 }
2010 
2011 void sysctl_head_put(struct ctl_table_header *head)
2012 {
2013 }
2014 
2015 #endif /* CONFIG_SYSCTL */
2016 
2017 /*
2018  * /proc/sys support
2019  */
2020 
2021 #ifdef CONFIG_PROC_SYSCTL
2022 
2023 static int _proc_do_string(void* data, int maxlen, int write,
2024 			   void __user *buffer,
2025 			   size_t *lenp, loff_t *ppos)
2026 {
2027 	size_t len;
2028 	char __user *p;
2029 	char c;
2030 
2031 	if (!data || !maxlen || !*lenp) {
2032 		*lenp = 0;
2033 		return 0;
2034 	}
2035 
2036 	if (write) {
2037 		len = 0;
2038 		p = buffer;
2039 		while (len < *lenp) {
2040 			if (get_user(c, p++))
2041 				return -EFAULT;
2042 			if (c == 0 || c == '\n')
2043 				break;
2044 			len++;
2045 		}
2046 		if (len >= maxlen)
2047 			len = maxlen-1;
2048 		if(copy_from_user(data, buffer, len))
2049 			return -EFAULT;
2050 		((char *) data)[len] = 0;
2051 		*ppos += *lenp;
2052 	} else {
2053 		len = strlen(data);
2054 		if (len > maxlen)
2055 			len = maxlen;
2056 
2057 		if (*ppos > len) {
2058 			*lenp = 0;
2059 			return 0;
2060 		}
2061 
2062 		data += *ppos;
2063 		len  -= *ppos;
2064 
2065 		if (len > *lenp)
2066 			len = *lenp;
2067 		if (len)
2068 			if(copy_to_user(buffer, data, len))
2069 				return -EFAULT;
2070 		if (len < *lenp) {
2071 			if(put_user('\n', ((char __user *) buffer) + len))
2072 				return -EFAULT;
2073 			len++;
2074 		}
2075 		*lenp = len;
2076 		*ppos += len;
2077 	}
2078 	return 0;
2079 }
2080 
2081 /**
2082  * proc_dostring - read a string sysctl
2083  * @table: the sysctl table
2084  * @write: %TRUE if this is a write to the sysctl file
2085  * @buffer: the user buffer
2086  * @lenp: the size of the user buffer
2087  * @ppos: file position
2088  *
2089  * Reads/writes a string from/to the user buffer. If the kernel
2090  * buffer provided is not large enough to hold the string, the
2091  * string is truncated. The copied string is %NULL-terminated.
2092  * If the string is being read by the user process, it is copied
2093  * and a newline '\n' is added. It is truncated if the buffer is
2094  * not large enough.
2095  *
2096  * Returns 0 on success.
2097  */
2098 int proc_dostring(struct ctl_table *table, int write,
2099 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2100 {
2101 	return _proc_do_string(table->data, table->maxlen, write,
2102 			       buffer, lenp, ppos);
2103 }
2104 
2105 static size_t proc_skip_spaces(char **buf)
2106 {
2107 	size_t ret;
2108 	char *tmp = skip_spaces(*buf);
2109 	ret = tmp - *buf;
2110 	*buf = tmp;
2111 	return ret;
2112 }
2113 
2114 static void proc_skip_char(char **buf, size_t *size, const char v)
2115 {
2116 	while (*size) {
2117 		if (**buf != v)
2118 			break;
2119 		(*size)--;
2120 		(*buf)++;
2121 	}
2122 }
2123 
2124 #define TMPBUFLEN 22
2125 /**
2126  * proc_get_long - reads an ASCII formatted integer from a user buffer
2127  *
2128  * @buf: a kernel buffer
2129  * @size: size of the kernel buffer
2130  * @val: this is where the number will be stored
2131  * @neg: set to %TRUE if number is negative
2132  * @perm_tr: a vector which contains the allowed trailers
2133  * @perm_tr_len: size of the perm_tr vector
2134  * @tr: pointer to store the trailer character
2135  *
2136  * In case of success %0 is returned and @buf and @size are updated with
2137  * the amount of bytes read. If @tr is non-NULL and a trailing
2138  * character exists (size is non-zero after returning from this
2139  * function), @tr is updated with the trailing character.
2140  */
2141 static int proc_get_long(char **buf, size_t *size,
2142 			  unsigned long *val, bool *neg,
2143 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
2144 {
2145 	int len;
2146 	char *p, tmp[TMPBUFLEN];
2147 
2148 	if (!*size)
2149 		return -EINVAL;
2150 
2151 	len = *size;
2152 	if (len > TMPBUFLEN - 1)
2153 		len = TMPBUFLEN - 1;
2154 
2155 	memcpy(tmp, *buf, len);
2156 
2157 	tmp[len] = 0;
2158 	p = tmp;
2159 	if (*p == '-' && *size > 1) {
2160 		*neg = true;
2161 		p++;
2162 	} else
2163 		*neg = false;
2164 	if (!isdigit(*p))
2165 		return -EINVAL;
2166 
2167 	*val = simple_strtoul(p, &p, 0);
2168 
2169 	len = p - tmp;
2170 
2171 	/* We don't know if the next char is whitespace thus we may accept
2172 	 * invalid integers (e.g. 1234...a) or two integers instead of one
2173 	 * (e.g. 123...1). So lets not allow such large numbers. */
2174 	if (len == TMPBUFLEN - 1)
2175 		return -EINVAL;
2176 
2177 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
2178 		return -EINVAL;
2179 
2180 	if (tr && (len < *size))
2181 		*tr = *p;
2182 
2183 	*buf += len;
2184 	*size -= len;
2185 
2186 	return 0;
2187 }
2188 
2189 /**
2190  * proc_put_long - converts an integer to a decimal ASCII formatted string
2191  *
2192  * @buf: the user buffer
2193  * @size: the size of the user buffer
2194  * @val: the integer to be converted
2195  * @neg: sign of the number, %TRUE for negative
2196  *
2197  * In case of success %0 is returned and @buf and @size are updated with
2198  * the amount of bytes written.
2199  */
2200 static int proc_put_long(void __user **buf, size_t *size, unsigned long val,
2201 			  bool neg)
2202 {
2203 	int len;
2204 	char tmp[TMPBUFLEN], *p = tmp;
2205 
2206 	sprintf(p, "%s%lu", neg ? "-" : "", val);
2207 	len = strlen(tmp);
2208 	if (len > *size)
2209 		len = *size;
2210 	if (copy_to_user(*buf, tmp, len))
2211 		return -EFAULT;
2212 	*size -= len;
2213 	*buf += len;
2214 	return 0;
2215 }
2216 #undef TMPBUFLEN
2217 
2218 static int proc_put_char(void __user **buf, size_t *size, char c)
2219 {
2220 	if (*size) {
2221 		char __user **buffer = (char __user **)buf;
2222 		if (put_user(c, *buffer))
2223 			return -EFAULT;
2224 		(*size)--, (*buffer)++;
2225 		*buf = *buffer;
2226 	}
2227 	return 0;
2228 }
2229 
2230 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
2231 				 int *valp,
2232 				 int write, void *data)
2233 {
2234 	if (write) {
2235 		*valp = *negp ? -*lvalp : *lvalp;
2236 	} else {
2237 		int val = *valp;
2238 		if (val < 0) {
2239 			*negp = true;
2240 			*lvalp = (unsigned long)-val;
2241 		} else {
2242 			*negp = false;
2243 			*lvalp = (unsigned long)val;
2244 		}
2245 	}
2246 	return 0;
2247 }
2248 
2249 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
2250 
2251 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
2252 		  int write, void __user *buffer,
2253 		  size_t *lenp, loff_t *ppos,
2254 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2255 			      int write, void *data),
2256 		  void *data)
2257 {
2258 	int *i, vleft, first = 1, err = 0;
2259 	unsigned long page = 0;
2260 	size_t left;
2261 	char *kbuf;
2262 
2263 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
2264 		*lenp = 0;
2265 		return 0;
2266 	}
2267 
2268 	i = (int *) tbl_data;
2269 	vleft = table->maxlen / sizeof(*i);
2270 	left = *lenp;
2271 
2272 	if (!conv)
2273 		conv = do_proc_dointvec_conv;
2274 
2275 	if (write) {
2276 		if (left > PAGE_SIZE - 1)
2277 			left = PAGE_SIZE - 1;
2278 		page = __get_free_page(GFP_TEMPORARY);
2279 		kbuf = (char *) page;
2280 		if (!kbuf)
2281 			return -ENOMEM;
2282 		if (copy_from_user(kbuf, buffer, left)) {
2283 			err = -EFAULT;
2284 			goto free;
2285 		}
2286 		kbuf[left] = 0;
2287 	}
2288 
2289 	for (; left && vleft--; i++, first=0) {
2290 		unsigned long lval;
2291 		bool neg;
2292 
2293 		if (write) {
2294 			left -= proc_skip_spaces(&kbuf);
2295 
2296 			if (!left)
2297 				break;
2298 			err = proc_get_long(&kbuf, &left, &lval, &neg,
2299 					     proc_wspace_sep,
2300 					     sizeof(proc_wspace_sep), NULL);
2301 			if (err)
2302 				break;
2303 			if (conv(&neg, &lval, i, 1, data)) {
2304 				err = -EINVAL;
2305 				break;
2306 			}
2307 		} else {
2308 			if (conv(&neg, &lval, i, 0, data)) {
2309 				err = -EINVAL;
2310 				break;
2311 			}
2312 			if (!first)
2313 				err = proc_put_char(&buffer, &left, '\t');
2314 			if (err)
2315 				break;
2316 			err = proc_put_long(&buffer, &left, lval, neg);
2317 			if (err)
2318 				break;
2319 		}
2320 	}
2321 
2322 	if (!write && !first && left && !err)
2323 		err = proc_put_char(&buffer, &left, '\n');
2324 	if (write && !err && left)
2325 		left -= proc_skip_spaces(&kbuf);
2326 free:
2327 	if (write) {
2328 		free_page(page);
2329 		if (first)
2330 			return err ? : -EINVAL;
2331 	}
2332 	*lenp -= left;
2333 	*ppos += *lenp;
2334 	return err;
2335 }
2336 
2337 static int do_proc_dointvec(struct ctl_table *table, int write,
2338 		  void __user *buffer, size_t *lenp, loff_t *ppos,
2339 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2340 			      int write, void *data),
2341 		  void *data)
2342 {
2343 	return __do_proc_dointvec(table->data, table, write,
2344 			buffer, lenp, ppos, conv, data);
2345 }
2346 
2347 /**
2348  * proc_dointvec - read a vector of integers
2349  * @table: the sysctl table
2350  * @write: %TRUE if this is a write to the sysctl file
2351  * @buffer: the user buffer
2352  * @lenp: the size of the user buffer
2353  * @ppos: file position
2354  *
2355  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2356  * values from/to the user buffer, treated as an ASCII string.
2357  *
2358  * Returns 0 on success.
2359  */
2360 int proc_dointvec(struct ctl_table *table, int write,
2361 		     void __user *buffer, size_t *lenp, loff_t *ppos)
2362 {
2363     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2364 		    	    NULL,NULL);
2365 }
2366 
2367 /*
2368  * Taint values can only be increased
2369  * This means we can safely use a temporary.
2370  */
2371 static int proc_taint(struct ctl_table *table, int write,
2372 			       void __user *buffer, size_t *lenp, loff_t *ppos)
2373 {
2374 	struct ctl_table t;
2375 	unsigned long tmptaint = get_taint();
2376 	int err;
2377 
2378 	if (write && !capable(CAP_SYS_ADMIN))
2379 		return -EPERM;
2380 
2381 	t = *table;
2382 	t.data = &tmptaint;
2383 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
2384 	if (err < 0)
2385 		return err;
2386 
2387 	if (write) {
2388 		/*
2389 		 * Poor man's atomic or. Not worth adding a primitive
2390 		 * to everyone's atomic.h for this
2391 		 */
2392 		int i;
2393 		for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
2394 			if ((tmptaint >> i) & 1)
2395 				add_taint(i);
2396 		}
2397 	}
2398 
2399 	return err;
2400 }
2401 
2402 struct do_proc_dointvec_minmax_conv_param {
2403 	int *min;
2404 	int *max;
2405 };
2406 
2407 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
2408 					int *valp,
2409 					int write, void *data)
2410 {
2411 	struct do_proc_dointvec_minmax_conv_param *param = data;
2412 	if (write) {
2413 		int val = *negp ? -*lvalp : *lvalp;
2414 		if ((param->min && *param->min > val) ||
2415 		    (param->max && *param->max < val))
2416 			return -EINVAL;
2417 		*valp = val;
2418 	} else {
2419 		int val = *valp;
2420 		if (val < 0) {
2421 			*negp = true;
2422 			*lvalp = (unsigned long)-val;
2423 		} else {
2424 			*negp = false;
2425 			*lvalp = (unsigned long)val;
2426 		}
2427 	}
2428 	return 0;
2429 }
2430 
2431 /**
2432  * proc_dointvec_minmax - read a vector of integers with min/max values
2433  * @table: the sysctl table
2434  * @write: %TRUE if this is a write to the sysctl file
2435  * @buffer: the user buffer
2436  * @lenp: the size of the user buffer
2437  * @ppos: file position
2438  *
2439  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2440  * values from/to the user buffer, treated as an ASCII string.
2441  *
2442  * This routine will ensure the values are within the range specified by
2443  * table->extra1 (min) and table->extra2 (max).
2444  *
2445  * Returns 0 on success.
2446  */
2447 int proc_dointvec_minmax(struct ctl_table *table, int write,
2448 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2449 {
2450 	struct do_proc_dointvec_minmax_conv_param param = {
2451 		.min = (int *) table->extra1,
2452 		.max = (int *) table->extra2,
2453 	};
2454 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2455 				do_proc_dointvec_minmax_conv, &param);
2456 }
2457 
2458 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
2459 				     void __user *buffer,
2460 				     size_t *lenp, loff_t *ppos,
2461 				     unsigned long convmul,
2462 				     unsigned long convdiv)
2463 {
2464 	unsigned long *i, *min, *max;
2465 	int vleft, first = 1, err = 0;
2466 	unsigned long page = 0;
2467 	size_t left;
2468 	char *kbuf;
2469 
2470 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
2471 		*lenp = 0;
2472 		return 0;
2473 	}
2474 
2475 	i = (unsigned long *) data;
2476 	min = (unsigned long *) table->extra1;
2477 	max = (unsigned long *) table->extra2;
2478 	vleft = table->maxlen / sizeof(unsigned long);
2479 	left = *lenp;
2480 
2481 	if (write) {
2482 		if (left > PAGE_SIZE - 1)
2483 			left = PAGE_SIZE - 1;
2484 		page = __get_free_page(GFP_TEMPORARY);
2485 		kbuf = (char *) page;
2486 		if (!kbuf)
2487 			return -ENOMEM;
2488 		if (copy_from_user(kbuf, buffer, left)) {
2489 			err = -EFAULT;
2490 			goto free;
2491 		}
2492 		kbuf[left] = 0;
2493 	}
2494 
2495 	for (; left && vleft--; i++, first = 0) {
2496 		unsigned long val;
2497 
2498 		if (write) {
2499 			bool neg;
2500 
2501 			left -= proc_skip_spaces(&kbuf);
2502 
2503 			err = proc_get_long(&kbuf, &left, &val, &neg,
2504 					     proc_wspace_sep,
2505 					     sizeof(proc_wspace_sep), NULL);
2506 			if (err)
2507 				break;
2508 			if (neg)
2509 				continue;
2510 			if ((min && val < *min) || (max && val > *max))
2511 				continue;
2512 			*i = val;
2513 		} else {
2514 			val = convdiv * (*i) / convmul;
2515 			if (!first)
2516 				err = proc_put_char(&buffer, &left, '\t');
2517 			err = proc_put_long(&buffer, &left, val, false);
2518 			if (err)
2519 				break;
2520 		}
2521 	}
2522 
2523 	if (!write && !first && left && !err)
2524 		err = proc_put_char(&buffer, &left, '\n');
2525 	if (write && !err)
2526 		left -= proc_skip_spaces(&kbuf);
2527 free:
2528 	if (write) {
2529 		free_page(page);
2530 		if (first)
2531 			return err ? : -EINVAL;
2532 	}
2533 	*lenp -= left;
2534 	*ppos += *lenp;
2535 	return err;
2536 }
2537 
2538 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
2539 				     void __user *buffer,
2540 				     size_t *lenp, loff_t *ppos,
2541 				     unsigned long convmul,
2542 				     unsigned long convdiv)
2543 {
2544 	return __do_proc_doulongvec_minmax(table->data, table, write,
2545 			buffer, lenp, ppos, convmul, convdiv);
2546 }
2547 
2548 /**
2549  * proc_doulongvec_minmax - read a vector of long integers with min/max values
2550  * @table: the sysctl table
2551  * @write: %TRUE if this is a write to the sysctl file
2552  * @buffer: the user buffer
2553  * @lenp: the size of the user buffer
2554  * @ppos: file position
2555  *
2556  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2557  * values from/to the user buffer, treated as an ASCII string.
2558  *
2559  * This routine will ensure the values are within the range specified by
2560  * table->extra1 (min) and table->extra2 (max).
2561  *
2562  * Returns 0 on success.
2563  */
2564 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2565 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2566 {
2567     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
2568 }
2569 
2570 /**
2571  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2572  * @table: the sysctl table
2573  * @write: %TRUE if this is a write to the sysctl file
2574  * @buffer: the user buffer
2575  * @lenp: the size of the user buffer
2576  * @ppos: file position
2577  *
2578  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2579  * values from/to the user buffer, treated as an ASCII string. The values
2580  * are treated as milliseconds, and converted to jiffies when they are stored.
2581  *
2582  * This routine will ensure the values are within the range specified by
2583  * table->extra1 (min) and table->extra2 (max).
2584  *
2585  * Returns 0 on success.
2586  */
2587 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2588 				      void __user *buffer,
2589 				      size_t *lenp, loff_t *ppos)
2590 {
2591     return do_proc_doulongvec_minmax(table, write, buffer,
2592 				     lenp, ppos, HZ, 1000l);
2593 }
2594 
2595 
2596 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
2597 					 int *valp,
2598 					 int write, void *data)
2599 {
2600 	if (write) {
2601 		if (*lvalp > LONG_MAX / HZ)
2602 			return 1;
2603 		*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2604 	} else {
2605 		int val = *valp;
2606 		unsigned long lval;
2607 		if (val < 0) {
2608 			*negp = true;
2609 			lval = (unsigned long)-val;
2610 		} else {
2611 			*negp = false;
2612 			lval = (unsigned long)val;
2613 		}
2614 		*lvalp = lval / HZ;
2615 	}
2616 	return 0;
2617 }
2618 
2619 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
2620 						int *valp,
2621 						int write, void *data)
2622 {
2623 	if (write) {
2624 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2625 			return 1;
2626 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2627 	} else {
2628 		int val = *valp;
2629 		unsigned long lval;
2630 		if (val < 0) {
2631 			*negp = true;
2632 			lval = (unsigned long)-val;
2633 		} else {
2634 			*negp = false;
2635 			lval = (unsigned long)val;
2636 		}
2637 		*lvalp = jiffies_to_clock_t(lval);
2638 	}
2639 	return 0;
2640 }
2641 
2642 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
2643 					    int *valp,
2644 					    int write, void *data)
2645 {
2646 	if (write) {
2647 		*valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2648 	} else {
2649 		int val = *valp;
2650 		unsigned long lval;
2651 		if (val < 0) {
2652 			*negp = true;
2653 			lval = (unsigned long)-val;
2654 		} else {
2655 			*negp = false;
2656 			lval = (unsigned long)val;
2657 		}
2658 		*lvalp = jiffies_to_msecs(lval);
2659 	}
2660 	return 0;
2661 }
2662 
2663 /**
2664  * proc_dointvec_jiffies - read a vector of integers as seconds
2665  * @table: the sysctl table
2666  * @write: %TRUE if this is a write to the sysctl file
2667  * @buffer: the user buffer
2668  * @lenp: the size of the user buffer
2669  * @ppos: file position
2670  *
2671  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2672  * values from/to the user buffer, treated as an ASCII string.
2673  * The values read are assumed to be in seconds, and are converted into
2674  * jiffies.
2675  *
2676  * Returns 0 on success.
2677  */
2678 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2679 			  void __user *buffer, size_t *lenp, loff_t *ppos)
2680 {
2681     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2682 		    	    do_proc_dointvec_jiffies_conv,NULL);
2683 }
2684 
2685 /**
2686  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2687  * @table: the sysctl table
2688  * @write: %TRUE if this is a write to the sysctl file
2689  * @buffer: the user buffer
2690  * @lenp: the size of the user buffer
2691  * @ppos: pointer to the file position
2692  *
2693  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2694  * values from/to the user buffer, treated as an ASCII string.
2695  * The values read are assumed to be in 1/USER_HZ seconds, and
2696  * are converted into jiffies.
2697  *
2698  * Returns 0 on success.
2699  */
2700 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2701 				 void __user *buffer, size_t *lenp, loff_t *ppos)
2702 {
2703     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2704 		    	    do_proc_dointvec_userhz_jiffies_conv,NULL);
2705 }
2706 
2707 /**
2708  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2709  * @table: the sysctl table
2710  * @write: %TRUE if this is a write to the sysctl file
2711  * @buffer: the user buffer
2712  * @lenp: the size of the user buffer
2713  * @ppos: file position
2714  * @ppos: the current position in the file
2715  *
2716  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2717  * values from/to the user buffer, treated as an ASCII string.
2718  * The values read are assumed to be in 1/1000 seconds, and
2719  * are converted into jiffies.
2720  *
2721  * Returns 0 on success.
2722  */
2723 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2724 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2725 {
2726 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2727 				do_proc_dointvec_ms_jiffies_conv, NULL);
2728 }
2729 
2730 static int proc_do_cad_pid(struct ctl_table *table, int write,
2731 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2732 {
2733 	struct pid *new_pid;
2734 	pid_t tmp;
2735 	int r;
2736 
2737 	tmp = pid_vnr(cad_pid);
2738 
2739 	r = __do_proc_dointvec(&tmp, table, write, buffer,
2740 			       lenp, ppos, NULL, NULL);
2741 	if (r || !write)
2742 		return r;
2743 
2744 	new_pid = find_get_pid(tmp);
2745 	if (!new_pid)
2746 		return -ESRCH;
2747 
2748 	put_pid(xchg(&cad_pid, new_pid));
2749 	return 0;
2750 }
2751 
2752 /**
2753  * proc_do_large_bitmap - read/write from/to a large bitmap
2754  * @table: the sysctl table
2755  * @write: %TRUE if this is a write to the sysctl file
2756  * @buffer: the user buffer
2757  * @lenp: the size of the user buffer
2758  * @ppos: file position
2759  *
2760  * The bitmap is stored at table->data and the bitmap length (in bits)
2761  * in table->maxlen.
2762  *
2763  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
2764  * large bitmaps may be represented in a compact manner. Writing into
2765  * the file will clear the bitmap then update it with the given input.
2766  *
2767  * Returns 0 on success.
2768  */
2769 int proc_do_large_bitmap(struct ctl_table *table, int write,
2770 			 void __user *buffer, size_t *lenp, loff_t *ppos)
2771 {
2772 	int err = 0;
2773 	bool first = 1;
2774 	size_t left = *lenp;
2775 	unsigned long bitmap_len = table->maxlen;
2776 	unsigned long *bitmap = (unsigned long *) table->data;
2777 	unsigned long *tmp_bitmap = NULL;
2778 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
2779 
2780 	if (!bitmap_len || !left || (*ppos && !write)) {
2781 		*lenp = 0;
2782 		return 0;
2783 	}
2784 
2785 	if (write) {
2786 		unsigned long page = 0;
2787 		char *kbuf;
2788 
2789 		if (left > PAGE_SIZE - 1)
2790 			left = PAGE_SIZE - 1;
2791 
2792 		page = __get_free_page(GFP_TEMPORARY);
2793 		kbuf = (char *) page;
2794 		if (!kbuf)
2795 			return -ENOMEM;
2796 		if (copy_from_user(kbuf, buffer, left)) {
2797 			free_page(page);
2798 			return -EFAULT;
2799                 }
2800 		kbuf[left] = 0;
2801 
2802 		tmp_bitmap = kzalloc(BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long),
2803 				     GFP_KERNEL);
2804 		if (!tmp_bitmap) {
2805 			free_page(page);
2806 			return -ENOMEM;
2807 		}
2808 		proc_skip_char(&kbuf, &left, '\n');
2809 		while (!err && left) {
2810 			unsigned long val_a, val_b;
2811 			bool neg;
2812 
2813 			err = proc_get_long(&kbuf, &left, &val_a, &neg, tr_a,
2814 					     sizeof(tr_a), &c);
2815 			if (err)
2816 				break;
2817 			if (val_a >= bitmap_len || neg) {
2818 				err = -EINVAL;
2819 				break;
2820 			}
2821 
2822 			val_b = val_a;
2823 			if (left) {
2824 				kbuf++;
2825 				left--;
2826 			}
2827 
2828 			if (c == '-') {
2829 				err = proc_get_long(&kbuf, &left, &val_b,
2830 						     &neg, tr_b, sizeof(tr_b),
2831 						     &c);
2832 				if (err)
2833 					break;
2834 				if (val_b >= bitmap_len || neg ||
2835 				    val_a > val_b) {
2836 					err = -EINVAL;
2837 					break;
2838 				}
2839 				if (left) {
2840 					kbuf++;
2841 					left--;
2842 				}
2843 			}
2844 
2845 			while (val_a <= val_b)
2846 				set_bit(val_a++, tmp_bitmap);
2847 
2848 			first = 0;
2849 			proc_skip_char(&kbuf, &left, '\n');
2850 		}
2851 		free_page(page);
2852 	} else {
2853 		unsigned long bit_a, bit_b = 0;
2854 
2855 		while (left) {
2856 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
2857 			if (bit_a >= bitmap_len)
2858 				break;
2859 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
2860 						   bit_a + 1) - 1;
2861 
2862 			if (!first) {
2863 				err = proc_put_char(&buffer, &left, ',');
2864 				if (err)
2865 					break;
2866 			}
2867 			err = proc_put_long(&buffer, &left, bit_a, false);
2868 			if (err)
2869 				break;
2870 			if (bit_a != bit_b) {
2871 				err = proc_put_char(&buffer, &left, '-');
2872 				if (err)
2873 					break;
2874 				err = proc_put_long(&buffer, &left, bit_b, false);
2875 				if (err)
2876 					break;
2877 			}
2878 
2879 			first = 0; bit_b++;
2880 		}
2881 		if (!err)
2882 			err = proc_put_char(&buffer, &left, '\n');
2883 	}
2884 
2885 	if (!err) {
2886 		if (write) {
2887 			if (*ppos)
2888 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
2889 			else
2890 				memcpy(bitmap, tmp_bitmap,
2891 					BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
2892 		}
2893 		kfree(tmp_bitmap);
2894 		*lenp -= left;
2895 		*ppos += *lenp;
2896 		return 0;
2897 	} else {
2898 		kfree(tmp_bitmap);
2899 		return err;
2900 	}
2901 }
2902 
2903 #else /* CONFIG_PROC_FS */
2904 
2905 int proc_dostring(struct ctl_table *table, int write,
2906 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2907 {
2908 	return -ENOSYS;
2909 }
2910 
2911 int proc_dointvec(struct ctl_table *table, int write,
2912 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2913 {
2914 	return -ENOSYS;
2915 }
2916 
2917 int proc_dointvec_minmax(struct ctl_table *table, int write,
2918 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2919 {
2920 	return -ENOSYS;
2921 }
2922 
2923 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2924 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2925 {
2926 	return -ENOSYS;
2927 }
2928 
2929 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2930 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2931 {
2932 	return -ENOSYS;
2933 }
2934 
2935 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2936 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2937 {
2938 	return -ENOSYS;
2939 }
2940 
2941 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2942 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2943 {
2944 	return -ENOSYS;
2945 }
2946 
2947 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2948 				      void __user *buffer,
2949 				      size_t *lenp, loff_t *ppos)
2950 {
2951     return -ENOSYS;
2952 }
2953 
2954 
2955 #endif /* CONFIG_PROC_FS */
2956 
2957 /*
2958  * No sense putting this after each symbol definition, twice,
2959  * exception granted :-)
2960  */
2961 EXPORT_SYMBOL(proc_dointvec);
2962 EXPORT_SYMBOL(proc_dointvec_jiffies);
2963 EXPORT_SYMBOL(proc_dointvec_minmax);
2964 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2965 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2966 EXPORT_SYMBOL(proc_dostring);
2967 EXPORT_SYMBOL(proc_doulongvec_minmax);
2968 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2969 EXPORT_SYMBOL(register_sysctl_table);
2970 EXPORT_SYMBOL(register_sysctl_paths);
2971 EXPORT_SYMBOL(unregister_sysctl_table);
2972