xref: /linux-6.15/kernel/sysctl.c (revision b898cc70)
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/syscalls.h>
48 #include <linux/vmstat.h>
49 #include <linux/nfs_fs.h>
50 #include <linux/acpi.h>
51 #include <linux/reboot.h>
52 #include <linux/ftrace.h>
53 #include <linux/perf_event.h>
54 #include <linux/kprobes.h>
55 #include <linux/pipe_fs_i.h>
56 #include <linux/oom.h>
57 
58 #include <asm/uaccess.h>
59 #include <asm/processor.h>
60 
61 #ifdef CONFIG_X86
62 #include <asm/nmi.h>
63 #include <asm/stacktrace.h>
64 #include <asm/io.h>
65 #endif
66 #ifdef CONFIG_BSD_PROCESS_ACCT
67 #include <linux/acct.h>
68 #endif
69 #ifdef CONFIG_RT_MUTEXES
70 #include <linux/rtmutex.h>
71 #endif
72 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_LOCK_STAT)
73 #include <linux/lockdep.h>
74 #endif
75 #ifdef CONFIG_CHR_DEV_SG
76 #include <scsi/sg.h>
77 #endif
78 
79 #ifdef CONFIG_LOCKUP_DETECTOR
80 #include <linux/nmi.h>
81 #endif
82 
83 
84 #if defined(CONFIG_SYSCTL)
85 
86 /* External variables not in a header file. */
87 extern int sysctl_overcommit_memory;
88 extern int sysctl_overcommit_ratio;
89 extern int max_threads;
90 extern int core_uses_pid;
91 extern int suid_dumpable;
92 extern char core_pattern[];
93 extern unsigned int core_pipe_limit;
94 extern int pid_max;
95 extern int min_free_kbytes;
96 extern int pid_max_min, pid_max_max;
97 extern int sysctl_drop_caches;
98 extern int percpu_pagelist_fraction;
99 extern int compat_log;
100 extern int latencytop_enabled;
101 extern int sysctl_nr_open_min, sysctl_nr_open_max;
102 #ifndef CONFIG_MMU
103 extern int sysctl_nr_trim_pages;
104 #endif
105 #ifdef CONFIG_BLOCK
106 extern int blk_iopoll_enabled;
107 #endif
108 
109 /* Constants used for minimum and  maximum */
110 #ifdef CONFIG_LOCKUP_DETECTOR
111 static int sixty = 60;
112 static int neg_one = -1;
113 #endif
114 
115 static int zero;
116 static int __maybe_unused one = 1;
117 static int __maybe_unused two = 2;
118 static unsigned long one_ul = 1;
119 static int one_hundred = 100;
120 #ifdef CONFIG_PRINTK
121 static int ten_thousand = 10000;
122 #endif
123 
124 /* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
125 static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;
126 
127 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
128 static int maxolduid = 65535;
129 static int minolduid;
130 static int min_percpu_pagelist_fract = 8;
131 
132 static int ngroups_max = NGROUPS_MAX;
133 
134 #ifdef CONFIG_SPARC
135 #include <asm/system.h>
136 #endif
137 
138 #ifdef CONFIG_SPARC64
139 extern int sysctl_tsb_ratio;
140 #endif
141 
142 #ifdef __hppa__
143 extern int pwrsw_enabled;
144 extern int unaligned_enabled;
145 #endif
146 
147 #ifdef CONFIG_S390
148 #ifdef CONFIG_MATHEMU
149 extern int sysctl_ieee_emulation_warnings;
150 #endif
151 extern int sysctl_userprocess_debug;
152 extern int spin_retry;
153 #endif
154 
155 #ifdef CONFIG_IA64
156 extern int no_unaligned_warning;
157 extern int unaligned_dump_stack;
158 #endif
159 
160 extern struct ratelimit_state printk_ratelimit_state;
161 
162 #ifdef CONFIG_PROC_SYSCTL
163 static int proc_do_cad_pid(struct ctl_table *table, int write,
164 		  void __user *buffer, size_t *lenp, loff_t *ppos);
165 static int proc_taint(struct ctl_table *table, int write,
166 			       void __user *buffer, size_t *lenp, loff_t *ppos);
167 #endif
168 
169 #ifdef CONFIG_MAGIC_SYSRQ
170 static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */
171 
172 static int sysrq_sysctl_handler(ctl_table *table, int write,
173 				void __user *buffer, size_t *lenp,
174 				loff_t *ppos)
175 {
176 	int error;
177 
178 	error = proc_dointvec(table, write, buffer, lenp, ppos);
179 	if (error)
180 		return error;
181 
182 	if (write)
183 		sysrq_toggle_support(__sysrq_enabled);
184 
185 	return 0;
186 }
187 
188 #endif
189 
190 static struct ctl_table root_table[];
191 static struct ctl_table_root sysctl_table_root;
192 static struct ctl_table_header root_table_header = {
193 	.count = 1,
194 	.ctl_table = root_table,
195 	.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),
196 	.root = &sysctl_table_root,
197 	.set = &sysctl_table_root.default_set,
198 };
199 static struct ctl_table_root sysctl_table_root = {
200 	.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
201 	.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
202 };
203 
204 static struct ctl_table kern_table[];
205 static struct ctl_table vm_table[];
206 static struct ctl_table fs_table[];
207 static struct ctl_table debug_table[];
208 static struct ctl_table dev_table[];
209 extern struct ctl_table random_table[];
210 #ifdef CONFIG_INOTIFY_USER
211 extern struct ctl_table inotify_table[];
212 #endif
213 #ifdef CONFIG_EPOLL
214 extern struct ctl_table epoll_table[];
215 #endif
216 
217 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
218 int sysctl_legacy_va_layout;
219 #endif
220 
221 /* The default sysctl tables: */
222 
223 static struct ctl_table root_table[] = {
224 	{
225 		.procname	= "kernel",
226 		.mode		= 0555,
227 		.child		= kern_table,
228 	},
229 	{
230 		.procname	= "vm",
231 		.mode		= 0555,
232 		.child		= vm_table,
233 	},
234 	{
235 		.procname	= "fs",
236 		.mode		= 0555,
237 		.child		= fs_table,
238 	},
239 	{
240 		.procname	= "debug",
241 		.mode		= 0555,
242 		.child		= debug_table,
243 	},
244 	{
245 		.procname	= "dev",
246 		.mode		= 0555,
247 		.child		= dev_table,
248 	},
249 /*
250  * NOTE: do not add new entries to this table unless you have read
251  * Documentation/sysctl/ctl_unnumbered.txt
252  */
253 	{ }
254 };
255 
256 #ifdef CONFIG_SCHED_DEBUG
257 static int min_sched_granularity_ns = 100000;		/* 100 usecs */
258 static int max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
259 static int min_wakeup_granularity_ns;			/* 0 usecs */
260 static int max_wakeup_granularity_ns = NSEC_PER_SEC;	/* 1 second */
261 static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
262 static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
263 static int min_sched_shares_ratelimit = 100000; /* 100 usec */
264 static int max_sched_shares_ratelimit = NSEC_PER_SEC; /* 1 second */
265 #endif
266 
267 #ifdef CONFIG_COMPACTION
268 static int min_extfrag_threshold;
269 static int max_extfrag_threshold = 1000;
270 #endif
271 
272 static struct ctl_table kern_table[] = {
273 	{
274 		.procname	= "sched_child_runs_first",
275 		.data		= &sysctl_sched_child_runs_first,
276 		.maxlen		= sizeof(unsigned int),
277 		.mode		= 0644,
278 		.proc_handler	= proc_dointvec,
279 	},
280 #ifdef CONFIG_SCHED_DEBUG
281 	{
282 		.procname	= "sched_min_granularity_ns",
283 		.data		= &sysctl_sched_min_granularity,
284 		.maxlen		= sizeof(unsigned int),
285 		.mode		= 0644,
286 		.proc_handler	= sched_proc_update_handler,
287 		.extra1		= &min_sched_granularity_ns,
288 		.extra2		= &max_sched_granularity_ns,
289 	},
290 	{
291 		.procname	= "sched_latency_ns",
292 		.data		= &sysctl_sched_latency,
293 		.maxlen		= sizeof(unsigned int),
294 		.mode		= 0644,
295 		.proc_handler	= sched_proc_update_handler,
296 		.extra1		= &min_sched_granularity_ns,
297 		.extra2		= &max_sched_granularity_ns,
298 	},
299 	{
300 		.procname	= "sched_wakeup_granularity_ns",
301 		.data		= &sysctl_sched_wakeup_granularity,
302 		.maxlen		= sizeof(unsigned int),
303 		.mode		= 0644,
304 		.proc_handler	= sched_proc_update_handler,
305 		.extra1		= &min_wakeup_granularity_ns,
306 		.extra2		= &max_wakeup_granularity_ns,
307 	},
308 	{
309 		.procname	= "sched_shares_ratelimit",
310 		.data		= &sysctl_sched_shares_ratelimit,
311 		.maxlen		= sizeof(unsigned int),
312 		.mode		= 0644,
313 		.proc_handler	= sched_proc_update_handler,
314 		.extra1		= &min_sched_shares_ratelimit,
315 		.extra2		= &max_sched_shares_ratelimit,
316 	},
317 	{
318 		.procname	= "sched_tunable_scaling",
319 		.data		= &sysctl_sched_tunable_scaling,
320 		.maxlen		= sizeof(enum sched_tunable_scaling),
321 		.mode		= 0644,
322 		.proc_handler	= sched_proc_update_handler,
323 		.extra1		= &min_sched_tunable_scaling,
324 		.extra2		= &max_sched_tunable_scaling,
325 	},
326 	{
327 		.procname	= "sched_shares_thresh",
328 		.data		= &sysctl_sched_shares_thresh,
329 		.maxlen		= sizeof(unsigned int),
330 		.mode		= 0644,
331 		.proc_handler	= proc_dointvec_minmax,
332 		.extra1		= &zero,
333 	},
334 	{
335 		.procname	= "sched_migration_cost",
336 		.data		= &sysctl_sched_migration_cost,
337 		.maxlen		= sizeof(unsigned int),
338 		.mode		= 0644,
339 		.proc_handler	= proc_dointvec,
340 	},
341 	{
342 		.procname	= "sched_nr_migrate",
343 		.data		= &sysctl_sched_nr_migrate,
344 		.maxlen		= sizeof(unsigned int),
345 		.mode		= 0644,
346 		.proc_handler	= proc_dointvec,
347 	},
348 	{
349 		.procname	= "sched_time_avg",
350 		.data		= &sysctl_sched_time_avg,
351 		.maxlen		= sizeof(unsigned int),
352 		.mode		= 0644,
353 		.proc_handler	= proc_dointvec,
354 	},
355 	{
356 		.procname	= "timer_migration",
357 		.data		= &sysctl_timer_migration,
358 		.maxlen		= sizeof(unsigned int),
359 		.mode		= 0644,
360 		.proc_handler	= proc_dointvec_minmax,
361 		.extra1		= &zero,
362 		.extra2		= &one,
363 	},
364 #endif
365 	{
366 		.procname	= "sched_rt_period_us",
367 		.data		= &sysctl_sched_rt_period,
368 		.maxlen		= sizeof(unsigned int),
369 		.mode		= 0644,
370 		.proc_handler	= sched_rt_handler,
371 	},
372 	{
373 		.procname	= "sched_rt_runtime_us",
374 		.data		= &sysctl_sched_rt_runtime,
375 		.maxlen		= sizeof(int),
376 		.mode		= 0644,
377 		.proc_handler	= sched_rt_handler,
378 	},
379 	{
380 		.procname	= "sched_compat_yield",
381 		.data		= &sysctl_sched_compat_yield,
382 		.maxlen		= sizeof(unsigned int),
383 		.mode		= 0644,
384 		.proc_handler	= proc_dointvec,
385 	},
386 #ifdef CONFIG_PROVE_LOCKING
387 	{
388 		.procname	= "prove_locking",
389 		.data		= &prove_locking,
390 		.maxlen		= sizeof(int),
391 		.mode		= 0644,
392 		.proc_handler	= proc_dointvec,
393 	},
394 #endif
395 #ifdef CONFIG_LOCK_STAT
396 	{
397 		.procname	= "lock_stat",
398 		.data		= &lock_stat,
399 		.maxlen		= sizeof(int),
400 		.mode		= 0644,
401 		.proc_handler	= proc_dointvec,
402 	},
403 #endif
404 	{
405 		.procname	= "panic",
406 		.data		= &panic_timeout,
407 		.maxlen		= sizeof(int),
408 		.mode		= 0644,
409 		.proc_handler	= proc_dointvec,
410 	},
411 	{
412 		.procname	= "core_uses_pid",
413 		.data		= &core_uses_pid,
414 		.maxlen		= sizeof(int),
415 		.mode		= 0644,
416 		.proc_handler	= proc_dointvec,
417 	},
418 	{
419 		.procname	= "core_pattern",
420 		.data		= core_pattern,
421 		.maxlen		= CORENAME_MAX_SIZE,
422 		.mode		= 0644,
423 		.proc_handler	= proc_dostring,
424 	},
425 	{
426 		.procname	= "core_pipe_limit",
427 		.data		= &core_pipe_limit,
428 		.maxlen		= sizeof(unsigned int),
429 		.mode		= 0644,
430 		.proc_handler	= proc_dointvec,
431 	},
432 #ifdef CONFIG_PROC_SYSCTL
433 	{
434 		.procname	= "tainted",
435 		.maxlen 	= sizeof(long),
436 		.mode		= 0644,
437 		.proc_handler	= proc_taint,
438 	},
439 #endif
440 #ifdef CONFIG_LATENCYTOP
441 	{
442 		.procname	= "latencytop",
443 		.data		= &latencytop_enabled,
444 		.maxlen		= sizeof(int),
445 		.mode		= 0644,
446 		.proc_handler	= proc_dointvec,
447 	},
448 #endif
449 #ifdef CONFIG_BLK_DEV_INITRD
450 	{
451 		.procname	= "real-root-dev",
452 		.data		= &real_root_dev,
453 		.maxlen		= sizeof(int),
454 		.mode		= 0644,
455 		.proc_handler	= proc_dointvec,
456 	},
457 #endif
458 	{
459 		.procname	= "print-fatal-signals",
460 		.data		= &print_fatal_signals,
461 		.maxlen		= sizeof(int),
462 		.mode		= 0644,
463 		.proc_handler	= proc_dointvec,
464 	},
465 #ifdef CONFIG_SPARC
466 	{
467 		.procname	= "reboot-cmd",
468 		.data		= reboot_command,
469 		.maxlen		= 256,
470 		.mode		= 0644,
471 		.proc_handler	= proc_dostring,
472 	},
473 	{
474 		.procname	= "stop-a",
475 		.data		= &stop_a_enabled,
476 		.maxlen		= sizeof (int),
477 		.mode		= 0644,
478 		.proc_handler	= proc_dointvec,
479 	},
480 	{
481 		.procname	= "scons-poweroff",
482 		.data		= &scons_pwroff,
483 		.maxlen		= sizeof (int),
484 		.mode		= 0644,
485 		.proc_handler	= proc_dointvec,
486 	},
487 #endif
488 #ifdef CONFIG_SPARC64
489 	{
490 		.procname	= "tsb-ratio",
491 		.data		= &sysctl_tsb_ratio,
492 		.maxlen		= sizeof (int),
493 		.mode		= 0644,
494 		.proc_handler	= proc_dointvec,
495 	},
496 #endif
497 #ifdef __hppa__
498 	{
499 		.procname	= "soft-power",
500 		.data		= &pwrsw_enabled,
501 		.maxlen		= sizeof (int),
502 	 	.mode		= 0644,
503 		.proc_handler	= proc_dointvec,
504 	},
505 	{
506 		.procname	= "unaligned-trap",
507 		.data		= &unaligned_enabled,
508 		.maxlen		= sizeof (int),
509 		.mode		= 0644,
510 		.proc_handler	= proc_dointvec,
511 	},
512 #endif
513 	{
514 		.procname	= "ctrl-alt-del",
515 		.data		= &C_A_D,
516 		.maxlen		= sizeof(int),
517 		.mode		= 0644,
518 		.proc_handler	= proc_dointvec,
519 	},
520 #ifdef CONFIG_FUNCTION_TRACER
521 	{
522 		.procname	= "ftrace_enabled",
523 		.data		= &ftrace_enabled,
524 		.maxlen		= sizeof(int),
525 		.mode		= 0644,
526 		.proc_handler	= ftrace_enable_sysctl,
527 	},
528 #endif
529 #ifdef CONFIG_STACK_TRACER
530 	{
531 		.procname	= "stack_tracer_enabled",
532 		.data		= &stack_tracer_enabled,
533 		.maxlen		= sizeof(int),
534 		.mode		= 0644,
535 		.proc_handler	= stack_trace_sysctl,
536 	},
537 #endif
538 #ifdef CONFIG_TRACING
539 	{
540 		.procname	= "ftrace_dump_on_oops",
541 		.data		= &ftrace_dump_on_oops,
542 		.maxlen		= sizeof(int),
543 		.mode		= 0644,
544 		.proc_handler	= proc_dointvec,
545 	},
546 #endif
547 #ifdef CONFIG_MODULES
548 	{
549 		.procname	= "modprobe",
550 		.data		= &modprobe_path,
551 		.maxlen		= KMOD_PATH_LEN,
552 		.mode		= 0644,
553 		.proc_handler	= proc_dostring,
554 	},
555 	{
556 		.procname	= "modules_disabled",
557 		.data		= &modules_disabled,
558 		.maxlen		= sizeof(int),
559 		.mode		= 0644,
560 		/* only handle a transition from default "0" to "1" */
561 		.proc_handler	= proc_dointvec_minmax,
562 		.extra1		= &one,
563 		.extra2		= &one,
564 	},
565 #endif
566 #ifdef CONFIG_HOTPLUG
567 	{
568 		.procname	= "hotplug",
569 		.data		= &uevent_helper,
570 		.maxlen		= UEVENT_HELPER_PATH_LEN,
571 		.mode		= 0644,
572 		.proc_handler	= proc_dostring,
573 	},
574 #endif
575 #ifdef CONFIG_CHR_DEV_SG
576 	{
577 		.procname	= "sg-big-buff",
578 		.data		= &sg_big_buff,
579 		.maxlen		= sizeof (int),
580 		.mode		= 0444,
581 		.proc_handler	= proc_dointvec,
582 	},
583 #endif
584 #ifdef CONFIG_BSD_PROCESS_ACCT
585 	{
586 		.procname	= "acct",
587 		.data		= &acct_parm,
588 		.maxlen		= 3*sizeof(int),
589 		.mode		= 0644,
590 		.proc_handler	= proc_dointvec,
591 	},
592 #endif
593 #ifdef CONFIG_MAGIC_SYSRQ
594 	{
595 		.procname	= "sysrq",
596 		.data		= &__sysrq_enabled,
597 		.maxlen		= sizeof (int),
598 		.mode		= 0644,
599 		.proc_handler	= sysrq_sysctl_handler,
600 	},
601 #endif
602 #ifdef CONFIG_PROC_SYSCTL
603 	{
604 		.procname	= "cad_pid",
605 		.data		= NULL,
606 		.maxlen		= sizeof (int),
607 		.mode		= 0600,
608 		.proc_handler	= proc_do_cad_pid,
609 	},
610 #endif
611 	{
612 		.procname	= "threads-max",
613 		.data		= &max_threads,
614 		.maxlen		= sizeof(int),
615 		.mode		= 0644,
616 		.proc_handler	= proc_dointvec,
617 	},
618 	{
619 		.procname	= "random",
620 		.mode		= 0555,
621 		.child		= random_table,
622 	},
623 	{
624 		.procname	= "overflowuid",
625 		.data		= &overflowuid,
626 		.maxlen		= sizeof(int),
627 		.mode		= 0644,
628 		.proc_handler	= proc_dointvec_minmax,
629 		.extra1		= &minolduid,
630 		.extra2		= &maxolduid,
631 	},
632 	{
633 		.procname	= "overflowgid",
634 		.data		= &overflowgid,
635 		.maxlen		= sizeof(int),
636 		.mode		= 0644,
637 		.proc_handler	= proc_dointvec_minmax,
638 		.extra1		= &minolduid,
639 		.extra2		= &maxolduid,
640 	},
641 #ifdef CONFIG_S390
642 #ifdef CONFIG_MATHEMU
643 	{
644 		.procname	= "ieee_emulation_warnings",
645 		.data		= &sysctl_ieee_emulation_warnings,
646 		.maxlen		= sizeof(int),
647 		.mode		= 0644,
648 		.proc_handler	= proc_dointvec,
649 	},
650 #endif
651 	{
652 		.procname	= "userprocess_debug",
653 		.data		= &show_unhandled_signals,
654 		.maxlen		= sizeof(int),
655 		.mode		= 0644,
656 		.proc_handler	= proc_dointvec,
657 	},
658 #endif
659 	{
660 		.procname	= "pid_max",
661 		.data		= &pid_max,
662 		.maxlen		= sizeof (int),
663 		.mode		= 0644,
664 		.proc_handler	= proc_dointvec_minmax,
665 		.extra1		= &pid_max_min,
666 		.extra2		= &pid_max_max,
667 	},
668 	{
669 		.procname	= "panic_on_oops",
670 		.data		= &panic_on_oops,
671 		.maxlen		= sizeof(int),
672 		.mode		= 0644,
673 		.proc_handler	= proc_dointvec,
674 	},
675 #if defined CONFIG_PRINTK
676 	{
677 		.procname	= "printk",
678 		.data		= &console_loglevel,
679 		.maxlen		= 4*sizeof(int),
680 		.mode		= 0644,
681 		.proc_handler	= proc_dointvec,
682 	},
683 	{
684 		.procname	= "printk_ratelimit",
685 		.data		= &printk_ratelimit_state.interval,
686 		.maxlen		= sizeof(int),
687 		.mode		= 0644,
688 		.proc_handler	= proc_dointvec_jiffies,
689 	},
690 	{
691 		.procname	= "printk_ratelimit_burst",
692 		.data		= &printk_ratelimit_state.burst,
693 		.maxlen		= sizeof(int),
694 		.mode		= 0644,
695 		.proc_handler	= proc_dointvec,
696 	},
697 	{
698 		.procname	= "printk_delay",
699 		.data		= &printk_delay_msec,
700 		.maxlen		= sizeof(int),
701 		.mode		= 0644,
702 		.proc_handler	= proc_dointvec_minmax,
703 		.extra1		= &zero,
704 		.extra2		= &ten_thousand,
705 	},
706 #endif
707 	{
708 		.procname	= "ngroups_max",
709 		.data		= &ngroups_max,
710 		.maxlen		= sizeof (int),
711 		.mode		= 0444,
712 		.proc_handler	= proc_dointvec,
713 	},
714 #if defined(CONFIG_LOCKUP_DETECTOR)
715 	{
716 		.procname       = "watchdog",
717 		.data           = &watchdog_enabled,
718 		.maxlen         = sizeof (int),
719 		.mode           = 0644,
720 		.proc_handler   = proc_dowatchdog_enabled,
721 	},
722 	{
723 		.procname	= "watchdog_thresh",
724 		.data		= &softlockup_thresh,
725 		.maxlen		= sizeof(int),
726 		.mode		= 0644,
727 		.proc_handler	= proc_dowatchdog_thresh,
728 		.extra1		= &neg_one,
729 		.extra2		= &sixty,
730 	},
731 	{
732 		.procname	= "softlockup_panic",
733 		.data		= &softlockup_panic,
734 		.maxlen		= sizeof(int),
735 		.mode		= 0644,
736 		.proc_handler	= proc_dointvec_minmax,
737 		.extra1		= &zero,
738 		.extra2		= &one,
739 	},
740 #endif
741 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
742 	{
743 		.procname       = "unknown_nmi_panic",
744 		.data           = &unknown_nmi_panic,
745 		.maxlen         = sizeof (int),
746 		.mode           = 0644,
747 		.proc_handler   = proc_dointvec,
748 	},
749 	{
750 		.procname       = "nmi_watchdog",
751 		.data           = &nmi_watchdog_enabled,
752 		.maxlen         = sizeof (int),
753 		.mode           = 0644,
754 		.proc_handler   = proc_nmi_enabled,
755 	},
756 #endif
757 #if defined(CONFIG_X86)
758 	{
759 		.procname	= "panic_on_unrecovered_nmi",
760 		.data		= &panic_on_unrecovered_nmi,
761 		.maxlen		= sizeof(int),
762 		.mode		= 0644,
763 		.proc_handler	= proc_dointvec,
764 	},
765 	{
766 		.procname	= "panic_on_io_nmi",
767 		.data		= &panic_on_io_nmi,
768 		.maxlen		= sizeof(int),
769 		.mode		= 0644,
770 		.proc_handler	= proc_dointvec,
771 	},
772 	{
773 		.procname	= "bootloader_type",
774 		.data		= &bootloader_type,
775 		.maxlen		= sizeof (int),
776 		.mode		= 0444,
777 		.proc_handler	= proc_dointvec,
778 	},
779 	{
780 		.procname	= "bootloader_version",
781 		.data		= &bootloader_version,
782 		.maxlen		= sizeof (int),
783 		.mode		= 0444,
784 		.proc_handler	= proc_dointvec,
785 	},
786 	{
787 		.procname	= "kstack_depth_to_print",
788 		.data		= &kstack_depth_to_print,
789 		.maxlen		= sizeof(int),
790 		.mode		= 0644,
791 		.proc_handler	= proc_dointvec,
792 	},
793 	{
794 		.procname	= "io_delay_type",
795 		.data		= &io_delay_type,
796 		.maxlen		= sizeof(int),
797 		.mode		= 0644,
798 		.proc_handler	= proc_dointvec,
799 	},
800 #endif
801 #if defined(CONFIG_MMU)
802 	{
803 		.procname	= "randomize_va_space",
804 		.data		= &randomize_va_space,
805 		.maxlen		= sizeof(int),
806 		.mode		= 0644,
807 		.proc_handler	= proc_dointvec,
808 	},
809 #endif
810 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
811 	{
812 		.procname	= "spin_retry",
813 		.data		= &spin_retry,
814 		.maxlen		= sizeof (int),
815 		.mode		= 0644,
816 		.proc_handler	= proc_dointvec,
817 	},
818 #endif
819 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
820 	{
821 		.procname	= "acpi_video_flags",
822 		.data		= &acpi_realmode_flags,
823 		.maxlen		= sizeof (unsigned long),
824 		.mode		= 0644,
825 		.proc_handler	= proc_doulongvec_minmax,
826 	},
827 #endif
828 #ifdef CONFIG_IA64
829 	{
830 		.procname	= "ignore-unaligned-usertrap",
831 		.data		= &no_unaligned_warning,
832 		.maxlen		= sizeof (int),
833 	 	.mode		= 0644,
834 		.proc_handler	= proc_dointvec,
835 	},
836 	{
837 		.procname	= "unaligned-dump-stack",
838 		.data		= &unaligned_dump_stack,
839 		.maxlen		= sizeof (int),
840 		.mode		= 0644,
841 		.proc_handler	= proc_dointvec,
842 	},
843 #endif
844 #ifdef CONFIG_DETECT_HUNG_TASK
845 	{
846 		.procname	= "hung_task_panic",
847 		.data		= &sysctl_hung_task_panic,
848 		.maxlen		= sizeof(int),
849 		.mode		= 0644,
850 		.proc_handler	= proc_dointvec_minmax,
851 		.extra1		= &zero,
852 		.extra2		= &one,
853 	},
854 	{
855 		.procname	= "hung_task_check_count",
856 		.data		= &sysctl_hung_task_check_count,
857 		.maxlen		= sizeof(unsigned long),
858 		.mode		= 0644,
859 		.proc_handler	= proc_doulongvec_minmax,
860 	},
861 	{
862 		.procname	= "hung_task_timeout_secs",
863 		.data		= &sysctl_hung_task_timeout_secs,
864 		.maxlen		= sizeof(unsigned long),
865 		.mode		= 0644,
866 		.proc_handler	= proc_dohung_task_timeout_secs,
867 	},
868 	{
869 		.procname	= "hung_task_warnings",
870 		.data		= &sysctl_hung_task_warnings,
871 		.maxlen		= sizeof(unsigned long),
872 		.mode		= 0644,
873 		.proc_handler	= proc_doulongvec_minmax,
874 	},
875 #endif
876 #ifdef CONFIG_COMPAT
877 	{
878 		.procname	= "compat-log",
879 		.data		= &compat_log,
880 		.maxlen		= sizeof (int),
881 	 	.mode		= 0644,
882 		.proc_handler	= proc_dointvec,
883 	},
884 #endif
885 #ifdef CONFIG_RT_MUTEXES
886 	{
887 		.procname	= "max_lock_depth",
888 		.data		= &max_lock_depth,
889 		.maxlen		= sizeof(int),
890 		.mode		= 0644,
891 		.proc_handler	= proc_dointvec,
892 	},
893 #endif
894 	{
895 		.procname	= "poweroff_cmd",
896 		.data		= &poweroff_cmd,
897 		.maxlen		= POWEROFF_CMD_PATH_LEN,
898 		.mode		= 0644,
899 		.proc_handler	= proc_dostring,
900 	},
901 #ifdef CONFIG_KEYS
902 	{
903 		.procname	= "keys",
904 		.mode		= 0555,
905 		.child		= key_sysctls,
906 	},
907 #endif
908 #ifdef CONFIG_RCU_TORTURE_TEST
909 	{
910 		.procname       = "rcutorture_runnable",
911 		.data           = &rcutorture_runnable,
912 		.maxlen         = sizeof(int),
913 		.mode           = 0644,
914 		.proc_handler	= proc_dointvec,
915 	},
916 #endif
917 #ifdef CONFIG_PERF_EVENTS
918 	{
919 		.procname	= "perf_event_paranoid",
920 		.data		= &sysctl_perf_event_paranoid,
921 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
922 		.mode		= 0644,
923 		.proc_handler	= proc_dointvec,
924 	},
925 	{
926 		.procname	= "perf_event_mlock_kb",
927 		.data		= &sysctl_perf_event_mlock,
928 		.maxlen		= sizeof(sysctl_perf_event_mlock),
929 		.mode		= 0644,
930 		.proc_handler	= proc_dointvec,
931 	},
932 	{
933 		.procname	= "perf_event_max_sample_rate",
934 		.data		= &sysctl_perf_event_sample_rate,
935 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
936 		.mode		= 0644,
937 		.proc_handler	= proc_dointvec,
938 	},
939 #endif
940 #ifdef CONFIG_KMEMCHECK
941 	{
942 		.procname	= "kmemcheck",
943 		.data		= &kmemcheck_enabled,
944 		.maxlen		= sizeof(int),
945 		.mode		= 0644,
946 		.proc_handler	= proc_dointvec,
947 	},
948 #endif
949 #ifdef CONFIG_BLOCK
950 	{
951 		.procname	= "blk_iopoll",
952 		.data		= &blk_iopoll_enabled,
953 		.maxlen		= sizeof(int),
954 		.mode		= 0644,
955 		.proc_handler	= proc_dointvec,
956 	},
957 #endif
958 /*
959  * NOTE: do not add new entries to this table unless you have read
960  * Documentation/sysctl/ctl_unnumbered.txt
961  */
962 	{ }
963 };
964 
965 static struct ctl_table vm_table[] = {
966 	{
967 		.procname	= "overcommit_memory",
968 		.data		= &sysctl_overcommit_memory,
969 		.maxlen		= sizeof(sysctl_overcommit_memory),
970 		.mode		= 0644,
971 		.proc_handler	= proc_dointvec,
972 	},
973 	{
974 		.procname	= "panic_on_oom",
975 		.data		= &sysctl_panic_on_oom,
976 		.maxlen		= sizeof(sysctl_panic_on_oom),
977 		.mode		= 0644,
978 		.proc_handler	= proc_dointvec,
979 	},
980 	{
981 		.procname	= "oom_kill_allocating_task",
982 		.data		= &sysctl_oom_kill_allocating_task,
983 		.maxlen		= sizeof(sysctl_oom_kill_allocating_task),
984 		.mode		= 0644,
985 		.proc_handler	= proc_dointvec,
986 	},
987 	{
988 		.procname	= "oom_dump_tasks",
989 		.data		= &sysctl_oom_dump_tasks,
990 		.maxlen		= sizeof(sysctl_oom_dump_tasks),
991 		.mode		= 0644,
992 		.proc_handler	= proc_dointvec,
993 	},
994 	{
995 		.procname	= "overcommit_ratio",
996 		.data		= &sysctl_overcommit_ratio,
997 		.maxlen		= sizeof(sysctl_overcommit_ratio),
998 		.mode		= 0644,
999 		.proc_handler	= proc_dointvec,
1000 	},
1001 	{
1002 		.procname	= "page-cluster",
1003 		.data		= &page_cluster,
1004 		.maxlen		= sizeof(int),
1005 		.mode		= 0644,
1006 		.proc_handler	= proc_dointvec,
1007 	},
1008 	{
1009 		.procname	= "dirty_background_ratio",
1010 		.data		= &dirty_background_ratio,
1011 		.maxlen		= sizeof(dirty_background_ratio),
1012 		.mode		= 0644,
1013 		.proc_handler	= dirty_background_ratio_handler,
1014 		.extra1		= &zero,
1015 		.extra2		= &one_hundred,
1016 	},
1017 	{
1018 		.procname	= "dirty_background_bytes",
1019 		.data		= &dirty_background_bytes,
1020 		.maxlen		= sizeof(dirty_background_bytes),
1021 		.mode		= 0644,
1022 		.proc_handler	= dirty_background_bytes_handler,
1023 		.extra1		= &one_ul,
1024 	},
1025 	{
1026 		.procname	= "dirty_ratio",
1027 		.data		= &vm_dirty_ratio,
1028 		.maxlen		= sizeof(vm_dirty_ratio),
1029 		.mode		= 0644,
1030 		.proc_handler	= dirty_ratio_handler,
1031 		.extra1		= &zero,
1032 		.extra2		= &one_hundred,
1033 	},
1034 	{
1035 		.procname	= "dirty_bytes",
1036 		.data		= &vm_dirty_bytes,
1037 		.maxlen		= sizeof(vm_dirty_bytes),
1038 		.mode		= 0644,
1039 		.proc_handler	= dirty_bytes_handler,
1040 		.extra1		= &dirty_bytes_min,
1041 	},
1042 	{
1043 		.procname	= "dirty_writeback_centisecs",
1044 		.data		= &dirty_writeback_interval,
1045 		.maxlen		= sizeof(dirty_writeback_interval),
1046 		.mode		= 0644,
1047 		.proc_handler	= dirty_writeback_centisecs_handler,
1048 	},
1049 	{
1050 		.procname	= "dirty_expire_centisecs",
1051 		.data		= &dirty_expire_interval,
1052 		.maxlen		= sizeof(dirty_expire_interval),
1053 		.mode		= 0644,
1054 		.proc_handler	= proc_dointvec,
1055 	},
1056 	{
1057 		.procname	= "nr_pdflush_threads",
1058 		.data		= &nr_pdflush_threads,
1059 		.maxlen		= sizeof nr_pdflush_threads,
1060 		.mode		= 0444 /* read-only*/,
1061 		.proc_handler	= proc_dointvec,
1062 	},
1063 	{
1064 		.procname	= "swappiness",
1065 		.data		= &vm_swappiness,
1066 		.maxlen		= sizeof(vm_swappiness),
1067 		.mode		= 0644,
1068 		.proc_handler	= proc_dointvec_minmax,
1069 		.extra1		= &zero,
1070 		.extra2		= &one_hundred,
1071 	},
1072 #ifdef CONFIG_HUGETLB_PAGE
1073 	{
1074 		.procname	= "nr_hugepages",
1075 		.data		= NULL,
1076 		.maxlen		= sizeof(unsigned long),
1077 		.mode		= 0644,
1078 		.proc_handler	= hugetlb_sysctl_handler,
1079 		.extra1		= (void *)&hugetlb_zero,
1080 		.extra2		= (void *)&hugetlb_infinity,
1081 	},
1082 #ifdef CONFIG_NUMA
1083 	{
1084 		.procname       = "nr_hugepages_mempolicy",
1085 		.data           = NULL,
1086 		.maxlen         = sizeof(unsigned long),
1087 		.mode           = 0644,
1088 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
1089 		.extra1		= (void *)&hugetlb_zero,
1090 		.extra2		= (void *)&hugetlb_infinity,
1091 	},
1092 #endif
1093 	 {
1094 		.procname	= "hugetlb_shm_group",
1095 		.data		= &sysctl_hugetlb_shm_group,
1096 		.maxlen		= sizeof(gid_t),
1097 		.mode		= 0644,
1098 		.proc_handler	= proc_dointvec,
1099 	 },
1100 	 {
1101 		.procname	= "hugepages_treat_as_movable",
1102 		.data		= &hugepages_treat_as_movable,
1103 		.maxlen		= sizeof(int),
1104 		.mode		= 0644,
1105 		.proc_handler	= hugetlb_treat_movable_handler,
1106 	},
1107 	{
1108 		.procname	= "nr_overcommit_hugepages",
1109 		.data		= NULL,
1110 		.maxlen		= sizeof(unsigned long),
1111 		.mode		= 0644,
1112 		.proc_handler	= hugetlb_overcommit_handler,
1113 		.extra1		= (void *)&hugetlb_zero,
1114 		.extra2		= (void *)&hugetlb_infinity,
1115 	},
1116 #endif
1117 	{
1118 		.procname	= "lowmem_reserve_ratio",
1119 		.data		= &sysctl_lowmem_reserve_ratio,
1120 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
1121 		.mode		= 0644,
1122 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
1123 	},
1124 	{
1125 		.procname	= "drop_caches",
1126 		.data		= &sysctl_drop_caches,
1127 		.maxlen		= sizeof(int),
1128 		.mode		= 0644,
1129 		.proc_handler	= drop_caches_sysctl_handler,
1130 	},
1131 #ifdef CONFIG_COMPACTION
1132 	{
1133 		.procname	= "compact_memory",
1134 		.data		= &sysctl_compact_memory,
1135 		.maxlen		= sizeof(int),
1136 		.mode		= 0200,
1137 		.proc_handler	= sysctl_compaction_handler,
1138 	},
1139 	{
1140 		.procname	= "extfrag_threshold",
1141 		.data		= &sysctl_extfrag_threshold,
1142 		.maxlen		= sizeof(int),
1143 		.mode		= 0644,
1144 		.proc_handler	= sysctl_extfrag_handler,
1145 		.extra1		= &min_extfrag_threshold,
1146 		.extra2		= &max_extfrag_threshold,
1147 	},
1148 
1149 #endif /* CONFIG_COMPACTION */
1150 	{
1151 		.procname	= "min_free_kbytes",
1152 		.data		= &min_free_kbytes,
1153 		.maxlen		= sizeof(min_free_kbytes),
1154 		.mode		= 0644,
1155 		.proc_handler	= min_free_kbytes_sysctl_handler,
1156 		.extra1		= &zero,
1157 	},
1158 	{
1159 		.procname	= "percpu_pagelist_fraction",
1160 		.data		= &percpu_pagelist_fraction,
1161 		.maxlen		= sizeof(percpu_pagelist_fraction),
1162 		.mode		= 0644,
1163 		.proc_handler	= percpu_pagelist_fraction_sysctl_handler,
1164 		.extra1		= &min_percpu_pagelist_fract,
1165 	},
1166 #ifdef CONFIG_MMU
1167 	{
1168 		.procname	= "max_map_count",
1169 		.data		= &sysctl_max_map_count,
1170 		.maxlen		= sizeof(sysctl_max_map_count),
1171 		.mode		= 0644,
1172 		.proc_handler	= proc_dointvec_minmax,
1173 		.extra1		= &zero,
1174 	},
1175 #else
1176 	{
1177 		.procname	= "nr_trim_pages",
1178 		.data		= &sysctl_nr_trim_pages,
1179 		.maxlen		= sizeof(sysctl_nr_trim_pages),
1180 		.mode		= 0644,
1181 		.proc_handler	= proc_dointvec_minmax,
1182 		.extra1		= &zero,
1183 	},
1184 #endif
1185 	{
1186 		.procname	= "laptop_mode",
1187 		.data		= &laptop_mode,
1188 		.maxlen		= sizeof(laptop_mode),
1189 		.mode		= 0644,
1190 		.proc_handler	= proc_dointvec_jiffies,
1191 	},
1192 	{
1193 		.procname	= "block_dump",
1194 		.data		= &block_dump,
1195 		.maxlen		= sizeof(block_dump),
1196 		.mode		= 0644,
1197 		.proc_handler	= proc_dointvec,
1198 		.extra1		= &zero,
1199 	},
1200 	{
1201 		.procname	= "vfs_cache_pressure",
1202 		.data		= &sysctl_vfs_cache_pressure,
1203 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
1204 		.mode		= 0644,
1205 		.proc_handler	= proc_dointvec,
1206 		.extra1		= &zero,
1207 	},
1208 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
1209 	{
1210 		.procname	= "legacy_va_layout",
1211 		.data		= &sysctl_legacy_va_layout,
1212 		.maxlen		= sizeof(sysctl_legacy_va_layout),
1213 		.mode		= 0644,
1214 		.proc_handler	= proc_dointvec,
1215 		.extra1		= &zero,
1216 	},
1217 #endif
1218 #ifdef CONFIG_NUMA
1219 	{
1220 		.procname	= "zone_reclaim_mode",
1221 		.data		= &zone_reclaim_mode,
1222 		.maxlen		= sizeof(zone_reclaim_mode),
1223 		.mode		= 0644,
1224 		.proc_handler	= proc_dointvec,
1225 		.extra1		= &zero,
1226 	},
1227 	{
1228 		.procname	= "min_unmapped_ratio",
1229 		.data		= &sysctl_min_unmapped_ratio,
1230 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
1231 		.mode		= 0644,
1232 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
1233 		.extra1		= &zero,
1234 		.extra2		= &one_hundred,
1235 	},
1236 	{
1237 		.procname	= "min_slab_ratio",
1238 		.data		= &sysctl_min_slab_ratio,
1239 		.maxlen		= sizeof(sysctl_min_slab_ratio),
1240 		.mode		= 0644,
1241 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
1242 		.extra1		= &zero,
1243 		.extra2		= &one_hundred,
1244 	},
1245 #endif
1246 #ifdef CONFIG_SMP
1247 	{
1248 		.procname	= "stat_interval",
1249 		.data		= &sysctl_stat_interval,
1250 		.maxlen		= sizeof(sysctl_stat_interval),
1251 		.mode		= 0644,
1252 		.proc_handler	= proc_dointvec_jiffies,
1253 	},
1254 #endif
1255 #ifdef CONFIG_MMU
1256 	{
1257 		.procname	= "mmap_min_addr",
1258 		.data		= &dac_mmap_min_addr,
1259 		.maxlen		= sizeof(unsigned long),
1260 		.mode		= 0644,
1261 		.proc_handler	= mmap_min_addr_handler,
1262 	},
1263 #endif
1264 #ifdef CONFIG_NUMA
1265 	{
1266 		.procname	= "numa_zonelist_order",
1267 		.data		= &numa_zonelist_order,
1268 		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
1269 		.mode		= 0644,
1270 		.proc_handler	= numa_zonelist_order_handler,
1271 	},
1272 #endif
1273 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
1274    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
1275 	{
1276 		.procname	= "vdso_enabled",
1277 		.data		= &vdso_enabled,
1278 		.maxlen		= sizeof(vdso_enabled),
1279 		.mode		= 0644,
1280 		.proc_handler	= proc_dointvec,
1281 		.extra1		= &zero,
1282 	},
1283 #endif
1284 #ifdef CONFIG_HIGHMEM
1285 	{
1286 		.procname	= "highmem_is_dirtyable",
1287 		.data		= &vm_highmem_is_dirtyable,
1288 		.maxlen		= sizeof(vm_highmem_is_dirtyable),
1289 		.mode		= 0644,
1290 		.proc_handler	= proc_dointvec_minmax,
1291 		.extra1		= &zero,
1292 		.extra2		= &one,
1293 	},
1294 #endif
1295 	{
1296 		.procname	= "scan_unevictable_pages",
1297 		.data		= &scan_unevictable_pages,
1298 		.maxlen		= sizeof(scan_unevictable_pages),
1299 		.mode		= 0644,
1300 		.proc_handler	= scan_unevictable_handler,
1301 	},
1302 #ifdef CONFIG_MEMORY_FAILURE
1303 	{
1304 		.procname	= "memory_failure_early_kill",
1305 		.data		= &sysctl_memory_failure_early_kill,
1306 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
1307 		.mode		= 0644,
1308 		.proc_handler	= proc_dointvec_minmax,
1309 		.extra1		= &zero,
1310 		.extra2		= &one,
1311 	},
1312 	{
1313 		.procname	= "memory_failure_recovery",
1314 		.data		= &sysctl_memory_failure_recovery,
1315 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
1316 		.mode		= 0644,
1317 		.proc_handler	= proc_dointvec_minmax,
1318 		.extra1		= &zero,
1319 		.extra2		= &one,
1320 	},
1321 #endif
1322 
1323 /*
1324  * NOTE: do not add new entries to this table unless you have read
1325  * Documentation/sysctl/ctl_unnumbered.txt
1326  */
1327 	{ }
1328 };
1329 
1330 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1331 static struct ctl_table binfmt_misc_table[] = {
1332 	{ }
1333 };
1334 #endif
1335 
1336 static struct ctl_table fs_table[] = {
1337 	{
1338 		.procname	= "inode-nr",
1339 		.data		= &inodes_stat,
1340 		.maxlen		= 2*sizeof(int),
1341 		.mode		= 0444,
1342 		.proc_handler	= proc_dointvec,
1343 	},
1344 	{
1345 		.procname	= "inode-state",
1346 		.data		= &inodes_stat,
1347 		.maxlen		= 7*sizeof(int),
1348 		.mode		= 0444,
1349 		.proc_handler	= proc_dointvec,
1350 	},
1351 	{
1352 		.procname	= "file-nr",
1353 		.data		= &files_stat,
1354 		.maxlen		= 3*sizeof(int),
1355 		.mode		= 0444,
1356 		.proc_handler	= proc_nr_files,
1357 	},
1358 	{
1359 		.procname	= "file-max",
1360 		.data		= &files_stat.max_files,
1361 		.maxlen		= sizeof(int),
1362 		.mode		= 0644,
1363 		.proc_handler	= proc_dointvec,
1364 	},
1365 	{
1366 		.procname	= "nr_open",
1367 		.data		= &sysctl_nr_open,
1368 		.maxlen		= sizeof(int),
1369 		.mode		= 0644,
1370 		.proc_handler	= proc_dointvec_minmax,
1371 		.extra1		= &sysctl_nr_open_min,
1372 		.extra2		= &sysctl_nr_open_max,
1373 	},
1374 	{
1375 		.procname	= "dentry-state",
1376 		.data		= &dentry_stat,
1377 		.maxlen		= 6*sizeof(int),
1378 		.mode		= 0444,
1379 		.proc_handler	= proc_dointvec,
1380 	},
1381 	{
1382 		.procname	= "overflowuid",
1383 		.data		= &fs_overflowuid,
1384 		.maxlen		= sizeof(int),
1385 		.mode		= 0644,
1386 		.proc_handler	= proc_dointvec_minmax,
1387 		.extra1		= &minolduid,
1388 		.extra2		= &maxolduid,
1389 	},
1390 	{
1391 		.procname	= "overflowgid",
1392 		.data		= &fs_overflowgid,
1393 		.maxlen		= sizeof(int),
1394 		.mode		= 0644,
1395 		.proc_handler	= proc_dointvec_minmax,
1396 		.extra1		= &minolduid,
1397 		.extra2		= &maxolduid,
1398 	},
1399 #ifdef CONFIG_FILE_LOCKING
1400 	{
1401 		.procname	= "leases-enable",
1402 		.data		= &leases_enable,
1403 		.maxlen		= sizeof(int),
1404 		.mode		= 0644,
1405 		.proc_handler	= proc_dointvec,
1406 	},
1407 #endif
1408 #ifdef CONFIG_DNOTIFY
1409 	{
1410 		.procname	= "dir-notify-enable",
1411 		.data		= &dir_notify_enable,
1412 		.maxlen		= sizeof(int),
1413 		.mode		= 0644,
1414 		.proc_handler	= proc_dointvec,
1415 	},
1416 #endif
1417 #ifdef CONFIG_MMU
1418 #ifdef CONFIG_FILE_LOCKING
1419 	{
1420 		.procname	= "lease-break-time",
1421 		.data		= &lease_break_time,
1422 		.maxlen		= sizeof(int),
1423 		.mode		= 0644,
1424 		.proc_handler	= proc_dointvec,
1425 	},
1426 #endif
1427 #ifdef CONFIG_AIO
1428 	{
1429 		.procname	= "aio-nr",
1430 		.data		= &aio_nr,
1431 		.maxlen		= sizeof(aio_nr),
1432 		.mode		= 0444,
1433 		.proc_handler	= proc_doulongvec_minmax,
1434 	},
1435 	{
1436 		.procname	= "aio-max-nr",
1437 		.data		= &aio_max_nr,
1438 		.maxlen		= sizeof(aio_max_nr),
1439 		.mode		= 0644,
1440 		.proc_handler	= proc_doulongvec_minmax,
1441 	},
1442 #endif /* CONFIG_AIO */
1443 #ifdef CONFIG_INOTIFY_USER
1444 	{
1445 		.procname	= "inotify",
1446 		.mode		= 0555,
1447 		.child		= inotify_table,
1448 	},
1449 #endif
1450 #ifdef CONFIG_EPOLL
1451 	{
1452 		.procname	= "epoll",
1453 		.mode		= 0555,
1454 		.child		= epoll_table,
1455 	},
1456 #endif
1457 #endif
1458 	{
1459 		.procname	= "suid_dumpable",
1460 		.data		= &suid_dumpable,
1461 		.maxlen		= sizeof(int),
1462 		.mode		= 0644,
1463 		.proc_handler	= proc_dointvec_minmax,
1464 		.extra1		= &zero,
1465 		.extra2		= &two,
1466 	},
1467 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1468 	{
1469 		.procname	= "binfmt_misc",
1470 		.mode		= 0555,
1471 		.child		= binfmt_misc_table,
1472 	},
1473 #endif
1474 	{
1475 		.procname	= "pipe-max-size",
1476 		.data		= &pipe_max_size,
1477 		.maxlen		= sizeof(int),
1478 		.mode		= 0644,
1479 		.proc_handler	= &pipe_proc_fn,
1480 		.extra1		= &pipe_min_size,
1481 	},
1482 /*
1483  * NOTE: do not add new entries to this table unless you have read
1484  * Documentation/sysctl/ctl_unnumbered.txt
1485  */
1486 	{ }
1487 };
1488 
1489 static struct ctl_table debug_table[] = {
1490 #if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_SPARC) || \
1491     defined(CONFIG_S390)
1492 	{
1493 		.procname	= "exception-trace",
1494 		.data		= &show_unhandled_signals,
1495 		.maxlen		= sizeof(int),
1496 		.mode		= 0644,
1497 		.proc_handler	= proc_dointvec
1498 	},
1499 #endif
1500 #if defined(CONFIG_OPTPROBES)
1501 	{
1502 		.procname	= "kprobes-optimization",
1503 		.data		= &sysctl_kprobes_optimization,
1504 		.maxlen		= sizeof(int),
1505 		.mode		= 0644,
1506 		.proc_handler	= proc_kprobes_optimization_handler,
1507 		.extra1		= &zero,
1508 		.extra2		= &one,
1509 	},
1510 #endif
1511 	{ }
1512 };
1513 
1514 static struct ctl_table dev_table[] = {
1515 	{ }
1516 };
1517 
1518 static DEFINE_SPINLOCK(sysctl_lock);
1519 
1520 /* called under sysctl_lock */
1521 static int use_table(struct ctl_table_header *p)
1522 {
1523 	if (unlikely(p->unregistering))
1524 		return 0;
1525 	p->used++;
1526 	return 1;
1527 }
1528 
1529 /* called under sysctl_lock */
1530 static void unuse_table(struct ctl_table_header *p)
1531 {
1532 	if (!--p->used)
1533 		if (unlikely(p->unregistering))
1534 			complete(p->unregistering);
1535 }
1536 
1537 /* called under sysctl_lock, will reacquire if has to wait */
1538 static void start_unregistering(struct ctl_table_header *p)
1539 {
1540 	/*
1541 	 * if p->used is 0, nobody will ever touch that entry again;
1542 	 * we'll eliminate all paths to it before dropping sysctl_lock
1543 	 */
1544 	if (unlikely(p->used)) {
1545 		struct completion wait;
1546 		init_completion(&wait);
1547 		p->unregistering = &wait;
1548 		spin_unlock(&sysctl_lock);
1549 		wait_for_completion(&wait);
1550 		spin_lock(&sysctl_lock);
1551 	} else {
1552 		/* anything non-NULL; we'll never dereference it */
1553 		p->unregistering = ERR_PTR(-EINVAL);
1554 	}
1555 	/*
1556 	 * do not remove from the list until nobody holds it; walking the
1557 	 * list in do_sysctl() relies on that.
1558 	 */
1559 	list_del_init(&p->ctl_entry);
1560 }
1561 
1562 void sysctl_head_get(struct ctl_table_header *head)
1563 {
1564 	spin_lock(&sysctl_lock);
1565 	head->count++;
1566 	spin_unlock(&sysctl_lock);
1567 }
1568 
1569 void sysctl_head_put(struct ctl_table_header *head)
1570 {
1571 	spin_lock(&sysctl_lock);
1572 	if (!--head->count)
1573 		kfree(head);
1574 	spin_unlock(&sysctl_lock);
1575 }
1576 
1577 struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
1578 {
1579 	if (!head)
1580 		BUG();
1581 	spin_lock(&sysctl_lock);
1582 	if (!use_table(head))
1583 		head = ERR_PTR(-ENOENT);
1584 	spin_unlock(&sysctl_lock);
1585 	return head;
1586 }
1587 
1588 void sysctl_head_finish(struct ctl_table_header *head)
1589 {
1590 	if (!head)
1591 		return;
1592 	spin_lock(&sysctl_lock);
1593 	unuse_table(head);
1594 	spin_unlock(&sysctl_lock);
1595 }
1596 
1597 static struct ctl_table_set *
1598 lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
1599 {
1600 	struct ctl_table_set *set = &root->default_set;
1601 	if (root->lookup)
1602 		set = root->lookup(root, namespaces);
1603 	return set;
1604 }
1605 
1606 static struct list_head *
1607 lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
1608 {
1609 	struct ctl_table_set *set = lookup_header_set(root, namespaces);
1610 	return &set->list;
1611 }
1612 
1613 struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
1614 					    struct ctl_table_header *prev)
1615 {
1616 	struct ctl_table_root *root;
1617 	struct list_head *header_list;
1618 	struct ctl_table_header *head;
1619 	struct list_head *tmp;
1620 
1621 	spin_lock(&sysctl_lock);
1622 	if (prev) {
1623 		head = prev;
1624 		tmp = &prev->ctl_entry;
1625 		unuse_table(prev);
1626 		goto next;
1627 	}
1628 	tmp = &root_table_header.ctl_entry;
1629 	for (;;) {
1630 		head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1631 
1632 		if (!use_table(head))
1633 			goto next;
1634 		spin_unlock(&sysctl_lock);
1635 		return head;
1636 	next:
1637 		root = head->root;
1638 		tmp = tmp->next;
1639 		header_list = lookup_header_list(root, namespaces);
1640 		if (tmp != header_list)
1641 			continue;
1642 
1643 		do {
1644 			root = list_entry(root->root_list.next,
1645 					struct ctl_table_root, root_list);
1646 			if (root == &sysctl_table_root)
1647 				goto out;
1648 			header_list = lookup_header_list(root, namespaces);
1649 		} while (list_empty(header_list));
1650 		tmp = header_list->next;
1651 	}
1652 out:
1653 	spin_unlock(&sysctl_lock);
1654 	return NULL;
1655 }
1656 
1657 struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1658 {
1659 	return __sysctl_head_next(current->nsproxy, prev);
1660 }
1661 
1662 void register_sysctl_root(struct ctl_table_root *root)
1663 {
1664 	spin_lock(&sysctl_lock);
1665 	list_add_tail(&root->root_list, &sysctl_table_root.root_list);
1666 	spin_unlock(&sysctl_lock);
1667 }
1668 
1669 /*
1670  * sysctl_perm does NOT grant the superuser all rights automatically, because
1671  * some sysctl variables are readonly even to root.
1672  */
1673 
1674 static int test_perm(int mode, int op)
1675 {
1676 	if (!current_euid())
1677 		mode >>= 6;
1678 	else if (in_egroup_p(0))
1679 		mode >>= 3;
1680 	if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
1681 		return 0;
1682 	return -EACCES;
1683 }
1684 
1685 int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
1686 {
1687 	int error;
1688 	int mode;
1689 
1690 	error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
1691 	if (error)
1692 		return error;
1693 
1694 	if (root->permissions)
1695 		mode = root->permissions(root, current->nsproxy, table);
1696 	else
1697 		mode = table->mode;
1698 
1699 	return test_perm(mode, op);
1700 }
1701 
1702 static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1703 {
1704 	for (; table->procname; table++) {
1705 		table->parent = parent;
1706 		if (table->child)
1707 			sysctl_set_parent(table, table->child);
1708 	}
1709 }
1710 
1711 static __init int sysctl_init(void)
1712 {
1713 	sysctl_set_parent(NULL, root_table);
1714 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1715 	{
1716 		int err;
1717 		err = sysctl_check_table(current->nsproxy, root_table);
1718 	}
1719 #endif
1720 	return 0;
1721 }
1722 
1723 core_initcall(sysctl_init);
1724 
1725 static struct ctl_table *is_branch_in(struct ctl_table *branch,
1726 				      struct ctl_table *table)
1727 {
1728 	struct ctl_table *p;
1729 	const char *s = branch->procname;
1730 
1731 	/* branch should have named subdirectory as its first element */
1732 	if (!s || !branch->child)
1733 		return NULL;
1734 
1735 	/* ... and nothing else */
1736 	if (branch[1].procname)
1737 		return NULL;
1738 
1739 	/* table should contain subdirectory with the same name */
1740 	for (p = table; p->procname; p++) {
1741 		if (!p->child)
1742 			continue;
1743 		if (p->procname && strcmp(p->procname, s) == 0)
1744 			return p;
1745 	}
1746 	return NULL;
1747 }
1748 
1749 /* see if attaching q to p would be an improvement */
1750 static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
1751 {
1752 	struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
1753 	struct ctl_table *next;
1754 	int is_better = 0;
1755 	int not_in_parent = !p->attached_by;
1756 
1757 	while ((next = is_branch_in(by, to)) != NULL) {
1758 		if (by == q->attached_by)
1759 			is_better = 1;
1760 		if (to == p->attached_by)
1761 			not_in_parent = 1;
1762 		by = by->child;
1763 		to = next->child;
1764 	}
1765 
1766 	if (is_better && not_in_parent) {
1767 		q->attached_by = by;
1768 		q->attached_to = to;
1769 		q->parent = p;
1770 	}
1771 }
1772 
1773 /**
1774  * __register_sysctl_paths - register a sysctl hierarchy
1775  * @root: List of sysctl headers to register on
1776  * @namespaces: Data to compute which lists of sysctl entries are visible
1777  * @path: The path to the directory the sysctl table is in.
1778  * @table: the top-level table structure
1779  *
1780  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1781  * array. A completely 0 filled entry terminates the table.
1782  *
1783  * The members of the &struct ctl_table structure are used as follows:
1784  *
1785  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1786  *            enter a sysctl file
1787  *
1788  * data - a pointer to data for use by proc_handler
1789  *
1790  * maxlen - the maximum size in bytes of the data
1791  *
1792  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1793  *
1794  * child - a pointer to the child sysctl table if this entry is a directory, or
1795  *         %NULL.
1796  *
1797  * proc_handler - the text handler routine (described below)
1798  *
1799  * de - for internal use by the sysctl routines
1800  *
1801  * extra1, extra2 - extra pointers usable by the proc handler routines
1802  *
1803  * Leaf nodes in the sysctl tree will be represented by a single file
1804  * under /proc; non-leaf nodes will be represented by directories.
1805  *
1806  * sysctl(2) can automatically manage read and write requests through
1807  * the sysctl table.  The data and maxlen fields of the ctl_table
1808  * struct enable minimal validation of the values being written to be
1809  * performed, and the mode field allows minimal authentication.
1810  *
1811  * There must be a proc_handler routine for any terminal nodes
1812  * mirrored under /proc/sys (non-terminals are handled by a built-in
1813  * directory handler).  Several default handlers are available to
1814  * cover common cases -
1815  *
1816  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1817  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1818  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1819  *
1820  * It is the handler's job to read the input buffer from user memory
1821  * and process it. The handler should return 0 on success.
1822  *
1823  * This routine returns %NULL on a failure to register, and a pointer
1824  * to the table header on success.
1825  */
1826 struct ctl_table_header *__register_sysctl_paths(
1827 	struct ctl_table_root *root,
1828 	struct nsproxy *namespaces,
1829 	const struct ctl_path *path, struct ctl_table *table)
1830 {
1831 	struct ctl_table_header *header;
1832 	struct ctl_table *new, **prevp;
1833 	unsigned int n, npath;
1834 	struct ctl_table_set *set;
1835 
1836 	/* Count the path components */
1837 	for (npath = 0; path[npath].procname; ++npath)
1838 		;
1839 
1840 	/*
1841 	 * For each path component, allocate a 2-element ctl_table array.
1842 	 * The first array element will be filled with the sysctl entry
1843 	 * for this, the second will be the sentinel (procname == 0).
1844 	 *
1845 	 * We allocate everything in one go so that we don't have to
1846 	 * worry about freeing additional memory in unregister_sysctl_table.
1847 	 */
1848 	header = kzalloc(sizeof(struct ctl_table_header) +
1849 			 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
1850 	if (!header)
1851 		return NULL;
1852 
1853 	new = (struct ctl_table *) (header + 1);
1854 
1855 	/* Now connect the dots */
1856 	prevp = &header->ctl_table;
1857 	for (n = 0; n < npath; ++n, ++path) {
1858 		/* Copy the procname */
1859 		new->procname = path->procname;
1860 		new->mode     = 0555;
1861 
1862 		*prevp = new;
1863 		prevp = &new->child;
1864 
1865 		new += 2;
1866 	}
1867 	*prevp = table;
1868 	header->ctl_table_arg = table;
1869 
1870 	INIT_LIST_HEAD(&header->ctl_entry);
1871 	header->used = 0;
1872 	header->unregistering = NULL;
1873 	header->root = root;
1874 	sysctl_set_parent(NULL, header->ctl_table);
1875 	header->count = 1;
1876 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1877 	if (sysctl_check_table(namespaces, header->ctl_table)) {
1878 		kfree(header);
1879 		return NULL;
1880 	}
1881 #endif
1882 	spin_lock(&sysctl_lock);
1883 	header->set = lookup_header_set(root, namespaces);
1884 	header->attached_by = header->ctl_table;
1885 	header->attached_to = root_table;
1886 	header->parent = &root_table_header;
1887 	for (set = header->set; set; set = set->parent) {
1888 		struct ctl_table_header *p;
1889 		list_for_each_entry(p, &set->list, ctl_entry) {
1890 			if (p->unregistering)
1891 				continue;
1892 			try_attach(p, header);
1893 		}
1894 	}
1895 	header->parent->count++;
1896 	list_add_tail(&header->ctl_entry, &header->set->list);
1897 	spin_unlock(&sysctl_lock);
1898 
1899 	return header;
1900 }
1901 
1902 /**
1903  * register_sysctl_table_path - register a sysctl table hierarchy
1904  * @path: The path to the directory the sysctl table is in.
1905  * @table: the top-level table structure
1906  *
1907  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1908  * array. A completely 0 filled entry terminates the table.
1909  *
1910  * See __register_sysctl_paths for more details.
1911  */
1912 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1913 						struct ctl_table *table)
1914 {
1915 	return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1916 					path, table);
1917 }
1918 
1919 /**
1920  * register_sysctl_table - register a sysctl table hierarchy
1921  * @table: the top-level table structure
1922  *
1923  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1924  * array. A completely 0 filled entry terminates the table.
1925  *
1926  * See register_sysctl_paths for more details.
1927  */
1928 struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1929 {
1930 	static const struct ctl_path null_path[] = { {} };
1931 
1932 	return register_sysctl_paths(null_path, table);
1933 }
1934 
1935 /**
1936  * unregister_sysctl_table - unregister a sysctl table hierarchy
1937  * @header: the header returned from register_sysctl_table
1938  *
1939  * Unregisters the sysctl table and all children. proc entries may not
1940  * actually be removed until they are no longer used by anyone.
1941  */
1942 void unregister_sysctl_table(struct ctl_table_header * header)
1943 {
1944 	might_sleep();
1945 
1946 	if (header == NULL)
1947 		return;
1948 
1949 	spin_lock(&sysctl_lock);
1950 	start_unregistering(header);
1951 	if (!--header->parent->count) {
1952 		WARN_ON(1);
1953 		kfree(header->parent);
1954 	}
1955 	if (!--header->count)
1956 		kfree(header);
1957 	spin_unlock(&sysctl_lock);
1958 }
1959 
1960 int sysctl_is_seen(struct ctl_table_header *p)
1961 {
1962 	struct ctl_table_set *set = p->set;
1963 	int res;
1964 	spin_lock(&sysctl_lock);
1965 	if (p->unregistering)
1966 		res = 0;
1967 	else if (!set->is_seen)
1968 		res = 1;
1969 	else
1970 		res = set->is_seen(set);
1971 	spin_unlock(&sysctl_lock);
1972 	return res;
1973 }
1974 
1975 void setup_sysctl_set(struct ctl_table_set *p,
1976 	struct ctl_table_set *parent,
1977 	int (*is_seen)(struct ctl_table_set *))
1978 {
1979 	INIT_LIST_HEAD(&p->list);
1980 	p->parent = parent ? parent : &sysctl_table_root.default_set;
1981 	p->is_seen = is_seen;
1982 }
1983 
1984 #else /* !CONFIG_SYSCTL */
1985 struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
1986 {
1987 	return NULL;
1988 }
1989 
1990 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1991 						    struct ctl_table *table)
1992 {
1993 	return NULL;
1994 }
1995 
1996 void unregister_sysctl_table(struct ctl_table_header * table)
1997 {
1998 }
1999 
2000 void setup_sysctl_set(struct ctl_table_set *p,
2001 	struct ctl_table_set *parent,
2002 	int (*is_seen)(struct ctl_table_set *))
2003 {
2004 }
2005 
2006 void sysctl_head_put(struct ctl_table_header *head)
2007 {
2008 }
2009 
2010 #endif /* CONFIG_SYSCTL */
2011 
2012 /*
2013  * /proc/sys support
2014  */
2015 
2016 #ifdef CONFIG_PROC_SYSCTL
2017 
2018 static int _proc_do_string(void* data, int maxlen, int write,
2019 			   void __user *buffer,
2020 			   size_t *lenp, loff_t *ppos)
2021 {
2022 	size_t len;
2023 	char __user *p;
2024 	char c;
2025 
2026 	if (!data || !maxlen || !*lenp) {
2027 		*lenp = 0;
2028 		return 0;
2029 	}
2030 
2031 	if (write) {
2032 		len = 0;
2033 		p = buffer;
2034 		while (len < *lenp) {
2035 			if (get_user(c, p++))
2036 				return -EFAULT;
2037 			if (c == 0 || c == '\n')
2038 				break;
2039 			len++;
2040 		}
2041 		if (len >= maxlen)
2042 			len = maxlen-1;
2043 		if(copy_from_user(data, buffer, len))
2044 			return -EFAULT;
2045 		((char *) data)[len] = 0;
2046 		*ppos += *lenp;
2047 	} else {
2048 		len = strlen(data);
2049 		if (len > maxlen)
2050 			len = maxlen;
2051 
2052 		if (*ppos > len) {
2053 			*lenp = 0;
2054 			return 0;
2055 		}
2056 
2057 		data += *ppos;
2058 		len  -= *ppos;
2059 
2060 		if (len > *lenp)
2061 			len = *lenp;
2062 		if (len)
2063 			if(copy_to_user(buffer, data, len))
2064 				return -EFAULT;
2065 		if (len < *lenp) {
2066 			if(put_user('\n', ((char __user *) buffer) + len))
2067 				return -EFAULT;
2068 			len++;
2069 		}
2070 		*lenp = len;
2071 		*ppos += len;
2072 	}
2073 	return 0;
2074 }
2075 
2076 /**
2077  * proc_dostring - read a string sysctl
2078  * @table: the sysctl table
2079  * @write: %TRUE if this is a write to the sysctl file
2080  * @buffer: the user buffer
2081  * @lenp: the size of the user buffer
2082  * @ppos: file position
2083  *
2084  * Reads/writes a string from/to the user buffer. If the kernel
2085  * buffer provided is not large enough to hold the string, the
2086  * string is truncated. The copied string is %NULL-terminated.
2087  * If the string is being read by the user process, it is copied
2088  * and a newline '\n' is added. It is truncated if the buffer is
2089  * not large enough.
2090  *
2091  * Returns 0 on success.
2092  */
2093 int proc_dostring(struct ctl_table *table, int write,
2094 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2095 {
2096 	return _proc_do_string(table->data, table->maxlen, write,
2097 			       buffer, lenp, ppos);
2098 }
2099 
2100 static size_t proc_skip_spaces(char **buf)
2101 {
2102 	size_t ret;
2103 	char *tmp = skip_spaces(*buf);
2104 	ret = tmp - *buf;
2105 	*buf = tmp;
2106 	return ret;
2107 }
2108 
2109 static void proc_skip_char(char **buf, size_t *size, const char v)
2110 {
2111 	while (*size) {
2112 		if (**buf != v)
2113 			break;
2114 		(*size)--;
2115 		(*buf)++;
2116 	}
2117 }
2118 
2119 #define TMPBUFLEN 22
2120 /**
2121  * proc_get_long - reads an ASCII formatted integer from a user buffer
2122  *
2123  * @buf: a kernel buffer
2124  * @size: size of the kernel buffer
2125  * @val: this is where the number will be stored
2126  * @neg: set to %TRUE if number is negative
2127  * @perm_tr: a vector which contains the allowed trailers
2128  * @perm_tr_len: size of the perm_tr vector
2129  * @tr: pointer to store the trailer character
2130  *
2131  * In case of success %0 is returned and @buf and @size are updated with
2132  * the amount of bytes read. If @tr is non-NULL and a trailing
2133  * character exists (size is non-zero after returning from this
2134  * function), @tr is updated with the trailing character.
2135  */
2136 static int proc_get_long(char **buf, size_t *size,
2137 			  unsigned long *val, bool *neg,
2138 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
2139 {
2140 	int len;
2141 	char *p, tmp[TMPBUFLEN];
2142 
2143 	if (!*size)
2144 		return -EINVAL;
2145 
2146 	len = *size;
2147 	if (len > TMPBUFLEN - 1)
2148 		len = TMPBUFLEN - 1;
2149 
2150 	memcpy(tmp, *buf, len);
2151 
2152 	tmp[len] = 0;
2153 	p = tmp;
2154 	if (*p == '-' && *size > 1) {
2155 		*neg = true;
2156 		p++;
2157 	} else
2158 		*neg = false;
2159 	if (!isdigit(*p))
2160 		return -EINVAL;
2161 
2162 	*val = simple_strtoul(p, &p, 0);
2163 
2164 	len = p - tmp;
2165 
2166 	/* We don't know if the next char is whitespace thus we may accept
2167 	 * invalid integers (e.g. 1234...a) or two integers instead of one
2168 	 * (e.g. 123...1). So lets not allow such large numbers. */
2169 	if (len == TMPBUFLEN - 1)
2170 		return -EINVAL;
2171 
2172 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
2173 		return -EINVAL;
2174 
2175 	if (tr && (len < *size))
2176 		*tr = *p;
2177 
2178 	*buf += len;
2179 	*size -= len;
2180 
2181 	return 0;
2182 }
2183 
2184 /**
2185  * proc_put_long - converts an integer to a decimal ASCII formatted string
2186  *
2187  * @buf: the user buffer
2188  * @size: the size of the user buffer
2189  * @val: the integer to be converted
2190  * @neg: sign of the number, %TRUE for negative
2191  *
2192  * In case of success %0 is returned and @buf and @size are updated with
2193  * the amount of bytes written.
2194  */
2195 static int proc_put_long(void __user **buf, size_t *size, unsigned long val,
2196 			  bool neg)
2197 {
2198 	int len;
2199 	char tmp[TMPBUFLEN], *p = tmp;
2200 
2201 	sprintf(p, "%s%lu", neg ? "-" : "", val);
2202 	len = strlen(tmp);
2203 	if (len > *size)
2204 		len = *size;
2205 	if (copy_to_user(*buf, tmp, len))
2206 		return -EFAULT;
2207 	*size -= len;
2208 	*buf += len;
2209 	return 0;
2210 }
2211 #undef TMPBUFLEN
2212 
2213 static int proc_put_char(void __user **buf, size_t *size, char c)
2214 {
2215 	if (*size) {
2216 		char __user **buffer = (char __user **)buf;
2217 		if (put_user(c, *buffer))
2218 			return -EFAULT;
2219 		(*size)--, (*buffer)++;
2220 		*buf = *buffer;
2221 	}
2222 	return 0;
2223 }
2224 
2225 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
2226 				 int *valp,
2227 				 int write, void *data)
2228 {
2229 	if (write) {
2230 		*valp = *negp ? -*lvalp : *lvalp;
2231 	} else {
2232 		int val = *valp;
2233 		if (val < 0) {
2234 			*negp = true;
2235 			*lvalp = (unsigned long)-val;
2236 		} else {
2237 			*negp = false;
2238 			*lvalp = (unsigned long)val;
2239 		}
2240 	}
2241 	return 0;
2242 }
2243 
2244 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
2245 
2246 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
2247 		  int write, void __user *buffer,
2248 		  size_t *lenp, loff_t *ppos,
2249 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2250 			      int write, void *data),
2251 		  void *data)
2252 {
2253 	int *i, vleft, first = 1, err = 0;
2254 	unsigned long page = 0;
2255 	size_t left;
2256 	char *kbuf;
2257 
2258 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
2259 		*lenp = 0;
2260 		return 0;
2261 	}
2262 
2263 	i = (int *) tbl_data;
2264 	vleft = table->maxlen / sizeof(*i);
2265 	left = *lenp;
2266 
2267 	if (!conv)
2268 		conv = do_proc_dointvec_conv;
2269 
2270 	if (write) {
2271 		if (left > PAGE_SIZE - 1)
2272 			left = PAGE_SIZE - 1;
2273 		page = __get_free_page(GFP_TEMPORARY);
2274 		kbuf = (char *) page;
2275 		if (!kbuf)
2276 			return -ENOMEM;
2277 		if (copy_from_user(kbuf, buffer, left)) {
2278 			err = -EFAULT;
2279 			goto free;
2280 		}
2281 		kbuf[left] = 0;
2282 	}
2283 
2284 	for (; left && vleft--; i++, first=0) {
2285 		unsigned long lval;
2286 		bool neg;
2287 
2288 		if (write) {
2289 			left -= proc_skip_spaces(&kbuf);
2290 
2291 			if (!left)
2292 				break;
2293 			err = proc_get_long(&kbuf, &left, &lval, &neg,
2294 					     proc_wspace_sep,
2295 					     sizeof(proc_wspace_sep), NULL);
2296 			if (err)
2297 				break;
2298 			if (conv(&neg, &lval, i, 1, data)) {
2299 				err = -EINVAL;
2300 				break;
2301 			}
2302 		} else {
2303 			if (conv(&neg, &lval, i, 0, data)) {
2304 				err = -EINVAL;
2305 				break;
2306 			}
2307 			if (!first)
2308 				err = proc_put_char(&buffer, &left, '\t');
2309 			if (err)
2310 				break;
2311 			err = proc_put_long(&buffer, &left, lval, neg);
2312 			if (err)
2313 				break;
2314 		}
2315 	}
2316 
2317 	if (!write && !first && left && !err)
2318 		err = proc_put_char(&buffer, &left, '\n');
2319 	if (write && !err && left)
2320 		left -= proc_skip_spaces(&kbuf);
2321 free:
2322 	if (write) {
2323 		free_page(page);
2324 		if (first)
2325 			return err ? : -EINVAL;
2326 	}
2327 	*lenp -= left;
2328 	*ppos += *lenp;
2329 	return err;
2330 }
2331 
2332 static int do_proc_dointvec(struct ctl_table *table, int write,
2333 		  void __user *buffer, size_t *lenp, loff_t *ppos,
2334 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2335 			      int write, void *data),
2336 		  void *data)
2337 {
2338 	return __do_proc_dointvec(table->data, table, write,
2339 			buffer, lenp, ppos, conv, data);
2340 }
2341 
2342 /**
2343  * proc_dointvec - read a vector of integers
2344  * @table: the sysctl table
2345  * @write: %TRUE if this is a write to the sysctl file
2346  * @buffer: the user buffer
2347  * @lenp: the size of the user buffer
2348  * @ppos: file position
2349  *
2350  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2351  * values from/to the user buffer, treated as an ASCII string.
2352  *
2353  * Returns 0 on success.
2354  */
2355 int proc_dointvec(struct ctl_table *table, int write,
2356 		     void __user *buffer, size_t *lenp, loff_t *ppos)
2357 {
2358     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2359 		    	    NULL,NULL);
2360 }
2361 
2362 /*
2363  * Taint values can only be increased
2364  * This means we can safely use a temporary.
2365  */
2366 static int proc_taint(struct ctl_table *table, int write,
2367 			       void __user *buffer, size_t *lenp, loff_t *ppos)
2368 {
2369 	struct ctl_table t;
2370 	unsigned long tmptaint = get_taint();
2371 	int err;
2372 
2373 	if (write && !capable(CAP_SYS_ADMIN))
2374 		return -EPERM;
2375 
2376 	t = *table;
2377 	t.data = &tmptaint;
2378 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
2379 	if (err < 0)
2380 		return err;
2381 
2382 	if (write) {
2383 		/*
2384 		 * Poor man's atomic or. Not worth adding a primitive
2385 		 * to everyone's atomic.h for this
2386 		 */
2387 		int i;
2388 		for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
2389 			if ((tmptaint >> i) & 1)
2390 				add_taint(i);
2391 		}
2392 	}
2393 
2394 	return err;
2395 }
2396 
2397 struct do_proc_dointvec_minmax_conv_param {
2398 	int *min;
2399 	int *max;
2400 };
2401 
2402 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
2403 					int *valp,
2404 					int write, void *data)
2405 {
2406 	struct do_proc_dointvec_minmax_conv_param *param = data;
2407 	if (write) {
2408 		int val = *negp ? -*lvalp : *lvalp;
2409 		if ((param->min && *param->min > val) ||
2410 		    (param->max && *param->max < val))
2411 			return -EINVAL;
2412 		*valp = val;
2413 	} else {
2414 		int val = *valp;
2415 		if (val < 0) {
2416 			*negp = true;
2417 			*lvalp = (unsigned long)-val;
2418 		} else {
2419 			*negp = false;
2420 			*lvalp = (unsigned long)val;
2421 		}
2422 	}
2423 	return 0;
2424 }
2425 
2426 /**
2427  * proc_dointvec_minmax - read a vector of integers with min/max values
2428  * @table: the sysctl table
2429  * @write: %TRUE if this is a write to the sysctl file
2430  * @buffer: the user buffer
2431  * @lenp: the size of the user buffer
2432  * @ppos: file position
2433  *
2434  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2435  * values from/to the user buffer, treated as an ASCII string.
2436  *
2437  * This routine will ensure the values are within the range specified by
2438  * table->extra1 (min) and table->extra2 (max).
2439  *
2440  * Returns 0 on success.
2441  */
2442 int proc_dointvec_minmax(struct ctl_table *table, int write,
2443 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2444 {
2445 	struct do_proc_dointvec_minmax_conv_param param = {
2446 		.min = (int *) table->extra1,
2447 		.max = (int *) table->extra2,
2448 	};
2449 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2450 				do_proc_dointvec_minmax_conv, &param);
2451 }
2452 
2453 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
2454 				     void __user *buffer,
2455 				     size_t *lenp, loff_t *ppos,
2456 				     unsigned long convmul,
2457 				     unsigned long convdiv)
2458 {
2459 	unsigned long *i, *min, *max;
2460 	int vleft, first = 1, err = 0;
2461 	unsigned long page = 0;
2462 	size_t left;
2463 	char *kbuf;
2464 
2465 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
2466 		*lenp = 0;
2467 		return 0;
2468 	}
2469 
2470 	i = (unsigned long *) data;
2471 	min = (unsigned long *) table->extra1;
2472 	max = (unsigned long *) table->extra2;
2473 	vleft = table->maxlen / sizeof(unsigned long);
2474 	left = *lenp;
2475 
2476 	if (write) {
2477 		if (left > PAGE_SIZE - 1)
2478 			left = PAGE_SIZE - 1;
2479 		page = __get_free_page(GFP_TEMPORARY);
2480 		kbuf = (char *) page;
2481 		if (!kbuf)
2482 			return -ENOMEM;
2483 		if (copy_from_user(kbuf, buffer, left)) {
2484 			err = -EFAULT;
2485 			goto free;
2486 		}
2487 		kbuf[left] = 0;
2488 	}
2489 
2490 	for (; left && vleft--; i++, min++, max++, first=0) {
2491 		unsigned long val;
2492 
2493 		if (write) {
2494 			bool neg;
2495 
2496 			left -= proc_skip_spaces(&kbuf);
2497 
2498 			err = proc_get_long(&kbuf, &left, &val, &neg,
2499 					     proc_wspace_sep,
2500 					     sizeof(proc_wspace_sep), NULL);
2501 			if (err)
2502 				break;
2503 			if (neg)
2504 				continue;
2505 			if ((min && val < *min) || (max && val > *max))
2506 				continue;
2507 			*i = val;
2508 		} else {
2509 			val = convdiv * (*i) / convmul;
2510 			if (!first)
2511 				err = proc_put_char(&buffer, &left, '\t');
2512 			err = proc_put_long(&buffer, &left, val, false);
2513 			if (err)
2514 				break;
2515 		}
2516 	}
2517 
2518 	if (!write && !first && left && !err)
2519 		err = proc_put_char(&buffer, &left, '\n');
2520 	if (write && !err)
2521 		left -= proc_skip_spaces(&kbuf);
2522 free:
2523 	if (write) {
2524 		free_page(page);
2525 		if (first)
2526 			return err ? : -EINVAL;
2527 	}
2528 	*lenp -= left;
2529 	*ppos += *lenp;
2530 	return err;
2531 }
2532 
2533 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
2534 				     void __user *buffer,
2535 				     size_t *lenp, loff_t *ppos,
2536 				     unsigned long convmul,
2537 				     unsigned long convdiv)
2538 {
2539 	return __do_proc_doulongvec_minmax(table->data, table, write,
2540 			buffer, lenp, ppos, convmul, convdiv);
2541 }
2542 
2543 /**
2544  * proc_doulongvec_minmax - read a vector of long integers with min/max values
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: file position
2550  *
2551  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2552  * values from/to the user buffer, treated as an ASCII string.
2553  *
2554  * This routine will ensure the values are within the range specified by
2555  * table->extra1 (min) and table->extra2 (max).
2556  *
2557  * Returns 0 on success.
2558  */
2559 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2560 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2561 {
2562     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
2563 }
2564 
2565 /**
2566  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
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  *
2573  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2574  * values from/to the user buffer, treated as an ASCII string. The values
2575  * are treated as milliseconds, and converted to jiffies when they are stored.
2576  *
2577  * This routine will ensure the values are within the range specified by
2578  * table->extra1 (min) and table->extra2 (max).
2579  *
2580  * Returns 0 on success.
2581  */
2582 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2583 				      void __user *buffer,
2584 				      size_t *lenp, loff_t *ppos)
2585 {
2586     return do_proc_doulongvec_minmax(table, write, buffer,
2587 				     lenp, ppos, HZ, 1000l);
2588 }
2589 
2590 
2591 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
2592 					 int *valp,
2593 					 int write, void *data)
2594 {
2595 	if (write) {
2596 		if (*lvalp > LONG_MAX / HZ)
2597 			return 1;
2598 		*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2599 	} else {
2600 		int val = *valp;
2601 		unsigned long lval;
2602 		if (val < 0) {
2603 			*negp = true;
2604 			lval = (unsigned long)-val;
2605 		} else {
2606 			*negp = false;
2607 			lval = (unsigned long)val;
2608 		}
2609 		*lvalp = lval / HZ;
2610 	}
2611 	return 0;
2612 }
2613 
2614 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
2615 						int *valp,
2616 						int write, void *data)
2617 {
2618 	if (write) {
2619 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2620 			return 1;
2621 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2622 	} else {
2623 		int val = *valp;
2624 		unsigned long lval;
2625 		if (val < 0) {
2626 			*negp = true;
2627 			lval = (unsigned long)-val;
2628 		} else {
2629 			*negp = false;
2630 			lval = (unsigned long)val;
2631 		}
2632 		*lvalp = jiffies_to_clock_t(lval);
2633 	}
2634 	return 0;
2635 }
2636 
2637 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
2638 					    int *valp,
2639 					    int write, void *data)
2640 {
2641 	if (write) {
2642 		*valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2643 	} else {
2644 		int val = *valp;
2645 		unsigned long lval;
2646 		if (val < 0) {
2647 			*negp = true;
2648 			lval = (unsigned long)-val;
2649 		} else {
2650 			*negp = false;
2651 			lval = (unsigned long)val;
2652 		}
2653 		*lvalp = jiffies_to_msecs(lval);
2654 	}
2655 	return 0;
2656 }
2657 
2658 /**
2659  * proc_dointvec_jiffies - read a vector of integers as seconds
2660  * @table: the sysctl table
2661  * @write: %TRUE if this is a write to the sysctl file
2662  * @buffer: the user buffer
2663  * @lenp: the size of the user buffer
2664  * @ppos: file position
2665  *
2666  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2667  * values from/to the user buffer, treated as an ASCII string.
2668  * The values read are assumed to be in seconds, and are converted into
2669  * jiffies.
2670  *
2671  * Returns 0 on success.
2672  */
2673 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2674 			  void __user *buffer, size_t *lenp, loff_t *ppos)
2675 {
2676     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2677 		    	    do_proc_dointvec_jiffies_conv,NULL);
2678 }
2679 
2680 /**
2681  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2682  * @table: the sysctl table
2683  * @write: %TRUE if this is a write to the sysctl file
2684  * @buffer: the user buffer
2685  * @lenp: the size of the user buffer
2686  * @ppos: pointer to the file position
2687  *
2688  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2689  * values from/to the user buffer, treated as an ASCII string.
2690  * The values read are assumed to be in 1/USER_HZ seconds, and
2691  * are converted into jiffies.
2692  *
2693  * Returns 0 on success.
2694  */
2695 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2696 				 void __user *buffer, size_t *lenp, loff_t *ppos)
2697 {
2698     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2699 		    	    do_proc_dointvec_userhz_jiffies_conv,NULL);
2700 }
2701 
2702 /**
2703  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2704  * @table: the sysctl table
2705  * @write: %TRUE if this is a write to the sysctl file
2706  * @buffer: the user buffer
2707  * @lenp: the size of the user buffer
2708  * @ppos: file position
2709  * @ppos: the current position in the file
2710  *
2711  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2712  * values from/to the user buffer, treated as an ASCII string.
2713  * The values read are assumed to be in 1/1000 seconds, and
2714  * are converted into jiffies.
2715  *
2716  * Returns 0 on success.
2717  */
2718 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2719 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2720 {
2721 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2722 				do_proc_dointvec_ms_jiffies_conv, NULL);
2723 }
2724 
2725 static int proc_do_cad_pid(struct ctl_table *table, int write,
2726 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2727 {
2728 	struct pid *new_pid;
2729 	pid_t tmp;
2730 	int r;
2731 
2732 	tmp = pid_vnr(cad_pid);
2733 
2734 	r = __do_proc_dointvec(&tmp, table, write, buffer,
2735 			       lenp, ppos, NULL, NULL);
2736 	if (r || !write)
2737 		return r;
2738 
2739 	new_pid = find_get_pid(tmp);
2740 	if (!new_pid)
2741 		return -ESRCH;
2742 
2743 	put_pid(xchg(&cad_pid, new_pid));
2744 	return 0;
2745 }
2746 
2747 /**
2748  * proc_do_large_bitmap - read/write from/to a large bitmap
2749  * @table: the sysctl table
2750  * @write: %TRUE if this is a write to the sysctl file
2751  * @buffer: the user buffer
2752  * @lenp: the size of the user buffer
2753  * @ppos: file position
2754  *
2755  * The bitmap is stored at table->data and the bitmap length (in bits)
2756  * in table->maxlen.
2757  *
2758  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
2759  * large bitmaps may be represented in a compact manner. Writing into
2760  * the file will clear the bitmap then update it with the given input.
2761  *
2762  * Returns 0 on success.
2763  */
2764 int proc_do_large_bitmap(struct ctl_table *table, int write,
2765 			 void __user *buffer, size_t *lenp, loff_t *ppos)
2766 {
2767 	int err = 0;
2768 	bool first = 1;
2769 	size_t left = *lenp;
2770 	unsigned long bitmap_len = table->maxlen;
2771 	unsigned long *bitmap = (unsigned long *) table->data;
2772 	unsigned long *tmp_bitmap = NULL;
2773 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
2774 
2775 	if (!bitmap_len || !left || (*ppos && !write)) {
2776 		*lenp = 0;
2777 		return 0;
2778 	}
2779 
2780 	if (write) {
2781 		unsigned long page = 0;
2782 		char *kbuf;
2783 
2784 		if (left > PAGE_SIZE - 1)
2785 			left = PAGE_SIZE - 1;
2786 
2787 		page = __get_free_page(GFP_TEMPORARY);
2788 		kbuf = (char *) page;
2789 		if (!kbuf)
2790 			return -ENOMEM;
2791 		if (copy_from_user(kbuf, buffer, left)) {
2792 			free_page(page);
2793 			return -EFAULT;
2794                 }
2795 		kbuf[left] = 0;
2796 
2797 		tmp_bitmap = kzalloc(BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long),
2798 				     GFP_KERNEL);
2799 		if (!tmp_bitmap) {
2800 			free_page(page);
2801 			return -ENOMEM;
2802 		}
2803 		proc_skip_char(&kbuf, &left, '\n');
2804 		while (!err && left) {
2805 			unsigned long val_a, val_b;
2806 			bool neg;
2807 
2808 			err = proc_get_long(&kbuf, &left, &val_a, &neg, tr_a,
2809 					     sizeof(tr_a), &c);
2810 			if (err)
2811 				break;
2812 			if (val_a >= bitmap_len || neg) {
2813 				err = -EINVAL;
2814 				break;
2815 			}
2816 
2817 			val_b = val_a;
2818 			if (left) {
2819 				kbuf++;
2820 				left--;
2821 			}
2822 
2823 			if (c == '-') {
2824 				err = proc_get_long(&kbuf, &left, &val_b,
2825 						     &neg, tr_b, sizeof(tr_b),
2826 						     &c);
2827 				if (err)
2828 					break;
2829 				if (val_b >= bitmap_len || neg ||
2830 				    val_a > val_b) {
2831 					err = -EINVAL;
2832 					break;
2833 				}
2834 				if (left) {
2835 					kbuf++;
2836 					left--;
2837 				}
2838 			}
2839 
2840 			while (val_a <= val_b)
2841 				set_bit(val_a++, tmp_bitmap);
2842 
2843 			first = 0;
2844 			proc_skip_char(&kbuf, &left, '\n');
2845 		}
2846 		free_page(page);
2847 	} else {
2848 		unsigned long bit_a, bit_b = 0;
2849 
2850 		while (left) {
2851 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
2852 			if (bit_a >= bitmap_len)
2853 				break;
2854 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
2855 						   bit_a + 1) - 1;
2856 
2857 			if (!first) {
2858 				err = proc_put_char(&buffer, &left, ',');
2859 				if (err)
2860 					break;
2861 			}
2862 			err = proc_put_long(&buffer, &left, bit_a, false);
2863 			if (err)
2864 				break;
2865 			if (bit_a != bit_b) {
2866 				err = proc_put_char(&buffer, &left, '-');
2867 				if (err)
2868 					break;
2869 				err = proc_put_long(&buffer, &left, bit_b, false);
2870 				if (err)
2871 					break;
2872 			}
2873 
2874 			first = 0; bit_b++;
2875 		}
2876 		if (!err)
2877 			err = proc_put_char(&buffer, &left, '\n');
2878 	}
2879 
2880 	if (!err) {
2881 		if (write) {
2882 			if (*ppos)
2883 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
2884 			else
2885 				memcpy(bitmap, tmp_bitmap,
2886 					BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
2887 		}
2888 		kfree(tmp_bitmap);
2889 		*lenp -= left;
2890 		*ppos += *lenp;
2891 		return 0;
2892 	} else {
2893 		kfree(tmp_bitmap);
2894 		return err;
2895 	}
2896 }
2897 
2898 #else /* CONFIG_PROC_FS */
2899 
2900 int proc_dostring(struct ctl_table *table, int write,
2901 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2902 {
2903 	return -ENOSYS;
2904 }
2905 
2906 int proc_dointvec(struct ctl_table *table, int write,
2907 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2908 {
2909 	return -ENOSYS;
2910 }
2911 
2912 int proc_dointvec_minmax(struct ctl_table *table, int write,
2913 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2914 {
2915 	return -ENOSYS;
2916 }
2917 
2918 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2919 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2920 {
2921 	return -ENOSYS;
2922 }
2923 
2924 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2925 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2926 {
2927 	return -ENOSYS;
2928 }
2929 
2930 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2931 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2932 {
2933 	return -ENOSYS;
2934 }
2935 
2936 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2937 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2938 {
2939 	return -ENOSYS;
2940 }
2941 
2942 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2943 				      void __user *buffer,
2944 				      size_t *lenp, loff_t *ppos)
2945 {
2946     return -ENOSYS;
2947 }
2948 
2949 
2950 #endif /* CONFIG_PROC_FS */
2951 
2952 /*
2953  * No sense putting this after each symbol definition, twice,
2954  * exception granted :-)
2955  */
2956 EXPORT_SYMBOL(proc_dointvec);
2957 EXPORT_SYMBOL(proc_dointvec_jiffies);
2958 EXPORT_SYMBOL(proc_dointvec_minmax);
2959 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2960 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2961 EXPORT_SYMBOL(proc_dostring);
2962 EXPORT_SYMBOL(proc_doulongvec_minmax);
2963 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2964 EXPORT_SYMBOL(register_sysctl_table);
2965 EXPORT_SYMBOL(register_sysctl_paths);
2966 EXPORT_SYMBOL(unregister_sysctl_table);
2967