xref: /openbmc/linux/kernel/sysctl.c (revision 4bacd796)
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 extern struct ratelimit_state printk_ratelimit_state;
165 
166 #ifdef CONFIG_PROC_SYSCTL
167 static int proc_do_cad_pid(struct ctl_table *table, int write,
168 		  void __user *buffer, size_t *lenp, loff_t *ppos);
169 static int proc_taint(struct ctl_table *table, int write,
170 			       void __user *buffer, size_t *lenp, loff_t *ppos);
171 #endif
172 
173 #ifdef CONFIG_MAGIC_SYSRQ
174 static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */
175 
176 static int sysrq_sysctl_handler(ctl_table *table, int write,
177 				void __user *buffer, size_t *lenp,
178 				loff_t *ppos)
179 {
180 	int error;
181 
182 	error = proc_dointvec(table, write, buffer, lenp, ppos);
183 	if (error)
184 		return error;
185 
186 	if (write)
187 		sysrq_toggle_support(__sysrq_enabled);
188 
189 	return 0;
190 }
191 
192 #endif
193 
194 static struct ctl_table root_table[];
195 static struct ctl_table_root sysctl_table_root;
196 static struct ctl_table_header root_table_header = {
197 	.count = 1,
198 	.ctl_table = root_table,
199 	.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),
200 	.root = &sysctl_table_root,
201 	.set = &sysctl_table_root.default_set,
202 };
203 static struct ctl_table_root sysctl_table_root = {
204 	.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
205 	.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
206 };
207 
208 static struct ctl_table kern_table[];
209 static struct ctl_table vm_table[];
210 static struct ctl_table fs_table[];
211 static struct ctl_table debug_table[];
212 static struct ctl_table dev_table[];
213 extern struct ctl_table random_table[];
214 #ifdef CONFIG_EPOLL
215 extern struct ctl_table epoll_table[];
216 #endif
217 
218 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
219 int sysctl_legacy_va_layout;
220 #endif
221 
222 /* The default sysctl tables: */
223 
224 static struct ctl_table root_table[] = {
225 	{
226 		.procname	= "kernel",
227 		.mode		= 0555,
228 		.child		= kern_table,
229 	},
230 	{
231 		.procname	= "vm",
232 		.mode		= 0555,
233 		.child		= vm_table,
234 	},
235 	{
236 		.procname	= "fs",
237 		.mode		= 0555,
238 		.child		= fs_table,
239 	},
240 	{
241 		.procname	= "debug",
242 		.mode		= 0555,
243 		.child		= debug_table,
244 	},
245 	{
246 		.procname	= "dev",
247 		.mode		= 0555,
248 		.child		= dev_table,
249 	},
250 /*
251  * NOTE: do not add new entries to this table unless you have read
252  * Documentation/sysctl/ctl_unnumbered.txt
253  */
254 	{ }
255 };
256 
257 #ifdef CONFIG_SCHED_DEBUG
258 static int min_sched_granularity_ns = 100000;		/* 100 usecs */
259 static int max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
260 static int min_wakeup_granularity_ns;			/* 0 usecs */
261 static int max_wakeup_granularity_ns = NSEC_PER_SEC;	/* 1 second */
262 static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
263 static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
264 static int min_sched_shares_ratelimit = 100000; /* 100 usec */
265 static int max_sched_shares_ratelimit = NSEC_PER_SEC; /* 1 second */
266 #endif
267 
268 #ifdef CONFIG_COMPACTION
269 static int min_extfrag_threshold;
270 static int max_extfrag_threshold = 1000;
271 #endif
272 
273 static struct ctl_table kern_table[] = {
274 	{
275 		.procname	= "sched_child_runs_first",
276 		.data		= &sysctl_sched_child_runs_first,
277 		.maxlen		= sizeof(unsigned int),
278 		.mode		= 0644,
279 		.proc_handler	= proc_dointvec,
280 	},
281 #ifdef CONFIG_SCHED_DEBUG
282 	{
283 		.procname	= "sched_min_granularity_ns",
284 		.data		= &sysctl_sched_min_granularity,
285 		.maxlen		= sizeof(unsigned int),
286 		.mode		= 0644,
287 		.proc_handler	= sched_proc_update_handler,
288 		.extra1		= &min_sched_granularity_ns,
289 		.extra2		= &max_sched_granularity_ns,
290 	},
291 	{
292 		.procname	= "sched_latency_ns",
293 		.data		= &sysctl_sched_latency,
294 		.maxlen		= sizeof(unsigned int),
295 		.mode		= 0644,
296 		.proc_handler	= sched_proc_update_handler,
297 		.extra1		= &min_sched_granularity_ns,
298 		.extra2		= &max_sched_granularity_ns,
299 	},
300 	{
301 		.procname	= "sched_wakeup_granularity_ns",
302 		.data		= &sysctl_sched_wakeup_granularity,
303 		.maxlen		= sizeof(unsigned int),
304 		.mode		= 0644,
305 		.proc_handler	= sched_proc_update_handler,
306 		.extra1		= &min_wakeup_granularity_ns,
307 		.extra2		= &max_wakeup_granularity_ns,
308 	},
309 	{
310 		.procname	= "sched_shares_ratelimit",
311 		.data		= &sysctl_sched_shares_ratelimit,
312 		.maxlen		= sizeof(unsigned int),
313 		.mode		= 0644,
314 		.proc_handler	= sched_proc_update_handler,
315 		.extra1		= &min_sched_shares_ratelimit,
316 		.extra2		= &max_sched_shares_ratelimit,
317 	},
318 	{
319 		.procname	= "sched_tunable_scaling",
320 		.data		= &sysctl_sched_tunable_scaling,
321 		.maxlen		= sizeof(enum sched_tunable_scaling),
322 		.mode		= 0644,
323 		.proc_handler	= sched_proc_update_handler,
324 		.extra1		= &min_sched_tunable_scaling,
325 		.extra2		= &max_sched_tunable_scaling,
326 	},
327 	{
328 		.procname	= "sched_shares_thresh",
329 		.data		= &sysctl_sched_shares_thresh,
330 		.maxlen		= sizeof(unsigned int),
331 		.mode		= 0644,
332 		.proc_handler	= proc_dointvec_minmax,
333 		.extra1		= &zero,
334 	},
335 	{
336 		.procname	= "sched_migration_cost",
337 		.data		= &sysctl_sched_migration_cost,
338 		.maxlen		= sizeof(unsigned int),
339 		.mode		= 0644,
340 		.proc_handler	= proc_dointvec,
341 	},
342 	{
343 		.procname	= "sched_nr_migrate",
344 		.data		= &sysctl_sched_nr_migrate,
345 		.maxlen		= sizeof(unsigned int),
346 		.mode		= 0644,
347 		.proc_handler	= proc_dointvec,
348 	},
349 	{
350 		.procname	= "sched_time_avg",
351 		.data		= &sysctl_sched_time_avg,
352 		.maxlen		= sizeof(unsigned int),
353 		.mode		= 0644,
354 		.proc_handler	= proc_dointvec,
355 	},
356 	{
357 		.procname	= "timer_migration",
358 		.data		= &sysctl_timer_migration,
359 		.maxlen		= sizeof(unsigned int),
360 		.mode		= 0644,
361 		.proc_handler	= proc_dointvec_minmax,
362 		.extra1		= &zero,
363 		.extra2		= &one,
364 	},
365 #endif
366 	{
367 		.procname	= "sched_rt_period_us",
368 		.data		= &sysctl_sched_rt_period,
369 		.maxlen		= sizeof(unsigned int),
370 		.mode		= 0644,
371 		.proc_handler	= sched_rt_handler,
372 	},
373 	{
374 		.procname	= "sched_rt_runtime_us",
375 		.data		= &sysctl_sched_rt_runtime,
376 		.maxlen		= sizeof(int),
377 		.mode		= 0644,
378 		.proc_handler	= sched_rt_handler,
379 	},
380 	{
381 		.procname	= "sched_compat_yield",
382 		.data		= &sysctl_sched_compat_yield,
383 		.maxlen		= sizeof(unsigned int),
384 		.mode		= 0644,
385 		.proc_handler	= proc_dointvec,
386 	},
387 #ifdef CONFIG_PROVE_LOCKING
388 	{
389 		.procname	= "prove_locking",
390 		.data		= &prove_locking,
391 		.maxlen		= sizeof(int),
392 		.mode		= 0644,
393 		.proc_handler	= proc_dointvec,
394 	},
395 #endif
396 #ifdef CONFIG_LOCK_STAT
397 	{
398 		.procname	= "lock_stat",
399 		.data		= &lock_stat,
400 		.maxlen		= sizeof(int),
401 		.mode		= 0644,
402 		.proc_handler	= proc_dointvec,
403 	},
404 #endif
405 	{
406 		.procname	= "panic",
407 		.data		= &panic_timeout,
408 		.maxlen		= sizeof(int),
409 		.mode		= 0644,
410 		.proc_handler	= proc_dointvec,
411 	},
412 	{
413 		.procname	= "core_uses_pid",
414 		.data		= &core_uses_pid,
415 		.maxlen		= sizeof(int),
416 		.mode		= 0644,
417 		.proc_handler	= proc_dointvec,
418 	},
419 	{
420 		.procname	= "core_pattern",
421 		.data		= core_pattern,
422 		.maxlen		= CORENAME_MAX_SIZE,
423 		.mode		= 0644,
424 		.proc_handler	= proc_dostring,
425 	},
426 	{
427 		.procname	= "core_pipe_limit",
428 		.data		= &core_pipe_limit,
429 		.maxlen		= sizeof(unsigned int),
430 		.mode		= 0644,
431 		.proc_handler	= proc_dointvec,
432 	},
433 #ifdef CONFIG_PROC_SYSCTL
434 	{
435 		.procname	= "tainted",
436 		.maxlen 	= sizeof(long),
437 		.mode		= 0644,
438 		.proc_handler	= proc_taint,
439 	},
440 #endif
441 #ifdef CONFIG_LATENCYTOP
442 	{
443 		.procname	= "latencytop",
444 		.data		= &latencytop_enabled,
445 		.maxlen		= sizeof(int),
446 		.mode		= 0644,
447 		.proc_handler	= proc_dointvec,
448 	},
449 #endif
450 #ifdef CONFIG_BLK_DEV_INITRD
451 	{
452 		.procname	= "real-root-dev",
453 		.data		= &real_root_dev,
454 		.maxlen		= sizeof(int),
455 		.mode		= 0644,
456 		.proc_handler	= proc_dointvec,
457 	},
458 #endif
459 	{
460 		.procname	= "print-fatal-signals",
461 		.data		= &print_fatal_signals,
462 		.maxlen		= sizeof(int),
463 		.mode		= 0644,
464 		.proc_handler	= proc_dointvec,
465 	},
466 #ifdef CONFIG_SPARC
467 	{
468 		.procname	= "reboot-cmd",
469 		.data		= reboot_command,
470 		.maxlen		= 256,
471 		.mode		= 0644,
472 		.proc_handler	= proc_dostring,
473 	},
474 	{
475 		.procname	= "stop-a",
476 		.data		= &stop_a_enabled,
477 		.maxlen		= sizeof (int),
478 		.mode		= 0644,
479 		.proc_handler	= proc_dointvec,
480 	},
481 	{
482 		.procname	= "scons-poweroff",
483 		.data		= &scons_pwroff,
484 		.maxlen		= sizeof (int),
485 		.mode		= 0644,
486 		.proc_handler	= proc_dointvec,
487 	},
488 #endif
489 #ifdef CONFIG_SPARC64
490 	{
491 		.procname	= "tsb-ratio",
492 		.data		= &sysctl_tsb_ratio,
493 		.maxlen		= sizeof (int),
494 		.mode		= 0644,
495 		.proc_handler	= proc_dointvec,
496 	},
497 #endif
498 #ifdef __hppa__
499 	{
500 		.procname	= "soft-power",
501 		.data		= &pwrsw_enabled,
502 		.maxlen		= sizeof (int),
503 	 	.mode		= 0644,
504 		.proc_handler	= proc_dointvec,
505 	},
506 	{
507 		.procname	= "unaligned-trap",
508 		.data		= &unaligned_enabled,
509 		.maxlen		= sizeof (int),
510 		.mode		= 0644,
511 		.proc_handler	= proc_dointvec,
512 	},
513 #endif
514 	{
515 		.procname	= "ctrl-alt-del",
516 		.data		= &C_A_D,
517 		.maxlen		= sizeof(int),
518 		.mode		= 0644,
519 		.proc_handler	= proc_dointvec,
520 	},
521 #ifdef CONFIG_FUNCTION_TRACER
522 	{
523 		.procname	= "ftrace_enabled",
524 		.data		= &ftrace_enabled,
525 		.maxlen		= sizeof(int),
526 		.mode		= 0644,
527 		.proc_handler	= ftrace_enable_sysctl,
528 	},
529 #endif
530 #ifdef CONFIG_STACK_TRACER
531 	{
532 		.procname	= "stack_tracer_enabled",
533 		.data		= &stack_tracer_enabled,
534 		.maxlen		= sizeof(int),
535 		.mode		= 0644,
536 		.proc_handler	= stack_trace_sysctl,
537 	},
538 #endif
539 #ifdef CONFIG_TRACING
540 	{
541 		.procname	= "ftrace_dump_on_oops",
542 		.data		= &ftrace_dump_on_oops,
543 		.maxlen		= sizeof(int),
544 		.mode		= 0644,
545 		.proc_handler	= proc_dointvec,
546 	},
547 #endif
548 #ifdef CONFIG_MODULES
549 	{
550 		.procname	= "modprobe",
551 		.data		= &modprobe_path,
552 		.maxlen		= KMOD_PATH_LEN,
553 		.mode		= 0644,
554 		.proc_handler	= proc_dostring,
555 	},
556 	{
557 		.procname	= "modules_disabled",
558 		.data		= &modules_disabled,
559 		.maxlen		= sizeof(int),
560 		.mode		= 0644,
561 		/* only handle a transition from default "0" to "1" */
562 		.proc_handler	= proc_dointvec_minmax,
563 		.extra1		= &one,
564 		.extra2		= &one,
565 	},
566 #endif
567 #ifdef CONFIG_HOTPLUG
568 	{
569 		.procname	= "hotplug",
570 		.data		= &uevent_helper,
571 		.maxlen		= UEVENT_HELPER_PATH_LEN,
572 		.mode		= 0644,
573 		.proc_handler	= proc_dostring,
574 	},
575 #endif
576 #ifdef CONFIG_CHR_DEV_SG
577 	{
578 		.procname	= "sg-big-buff",
579 		.data		= &sg_big_buff,
580 		.maxlen		= sizeof (int),
581 		.mode		= 0444,
582 		.proc_handler	= proc_dointvec,
583 	},
584 #endif
585 #ifdef CONFIG_BSD_PROCESS_ACCT
586 	{
587 		.procname	= "acct",
588 		.data		= &acct_parm,
589 		.maxlen		= 3*sizeof(int),
590 		.mode		= 0644,
591 		.proc_handler	= proc_dointvec,
592 	},
593 #endif
594 #ifdef CONFIG_MAGIC_SYSRQ
595 	{
596 		.procname	= "sysrq",
597 		.data		= &__sysrq_enabled,
598 		.maxlen		= sizeof (int),
599 		.mode		= 0644,
600 		.proc_handler	= sysrq_sysctl_handler,
601 	},
602 #endif
603 #ifdef CONFIG_PROC_SYSCTL
604 	{
605 		.procname	= "cad_pid",
606 		.data		= NULL,
607 		.maxlen		= sizeof (int),
608 		.mode		= 0600,
609 		.proc_handler	= proc_do_cad_pid,
610 	},
611 #endif
612 	{
613 		.procname	= "threads-max",
614 		.data		= &max_threads,
615 		.maxlen		= sizeof(int),
616 		.mode		= 0644,
617 		.proc_handler	= proc_dointvec,
618 	},
619 	{
620 		.procname	= "random",
621 		.mode		= 0555,
622 		.child		= random_table,
623 	},
624 	{
625 		.procname	= "overflowuid",
626 		.data		= &overflowuid,
627 		.maxlen		= sizeof(int),
628 		.mode		= 0644,
629 		.proc_handler	= proc_dointvec_minmax,
630 		.extra1		= &minolduid,
631 		.extra2		= &maxolduid,
632 	},
633 	{
634 		.procname	= "overflowgid",
635 		.data		= &overflowgid,
636 		.maxlen		= sizeof(int),
637 		.mode		= 0644,
638 		.proc_handler	= proc_dointvec_minmax,
639 		.extra1		= &minolduid,
640 		.extra2		= &maxolduid,
641 	},
642 #ifdef CONFIG_S390
643 #ifdef CONFIG_MATHEMU
644 	{
645 		.procname	= "ieee_emulation_warnings",
646 		.data		= &sysctl_ieee_emulation_warnings,
647 		.maxlen		= sizeof(int),
648 		.mode		= 0644,
649 		.proc_handler	= proc_dointvec,
650 	},
651 #endif
652 	{
653 		.procname	= "userprocess_debug",
654 		.data		= &show_unhandled_signals,
655 		.maxlen		= sizeof(int),
656 		.mode		= 0644,
657 		.proc_handler	= proc_dointvec,
658 	},
659 #endif
660 	{
661 		.procname	= "pid_max",
662 		.data		= &pid_max,
663 		.maxlen		= sizeof (int),
664 		.mode		= 0644,
665 		.proc_handler	= proc_dointvec_minmax,
666 		.extra1		= &pid_max_min,
667 		.extra2		= &pid_max_max,
668 	},
669 	{
670 		.procname	= "panic_on_oops",
671 		.data		= &panic_on_oops,
672 		.maxlen		= sizeof(int),
673 		.mode		= 0644,
674 		.proc_handler	= proc_dointvec,
675 	},
676 #if defined CONFIG_PRINTK
677 	{
678 		.procname	= "printk",
679 		.data		= &console_loglevel,
680 		.maxlen		= 4*sizeof(int),
681 		.mode		= 0644,
682 		.proc_handler	= proc_dointvec,
683 	},
684 	{
685 		.procname	= "printk_ratelimit",
686 		.data		= &printk_ratelimit_state.interval,
687 		.maxlen		= sizeof(int),
688 		.mode		= 0644,
689 		.proc_handler	= proc_dointvec_jiffies,
690 	},
691 	{
692 		.procname	= "printk_ratelimit_burst",
693 		.data		= &printk_ratelimit_state.burst,
694 		.maxlen		= sizeof(int),
695 		.mode		= 0644,
696 		.proc_handler	= proc_dointvec,
697 	},
698 	{
699 		.procname	= "printk_delay",
700 		.data		= &printk_delay_msec,
701 		.maxlen		= sizeof(int),
702 		.mode		= 0644,
703 		.proc_handler	= proc_dointvec_minmax,
704 		.extra1		= &zero,
705 		.extra2		= &ten_thousand,
706 	},
707 #endif
708 	{
709 		.procname	= "ngroups_max",
710 		.data		= &ngroups_max,
711 		.maxlen		= sizeof (int),
712 		.mode		= 0444,
713 		.proc_handler	= proc_dointvec,
714 	},
715 #if defined(CONFIG_LOCKUP_DETECTOR)
716 	{
717 		.procname       = "watchdog",
718 		.data           = &watchdog_enabled,
719 		.maxlen         = sizeof (int),
720 		.mode           = 0644,
721 		.proc_handler   = proc_dowatchdog_enabled,
722 	},
723 	{
724 		.procname	= "watchdog_thresh",
725 		.data		= &softlockup_thresh,
726 		.maxlen		= sizeof(int),
727 		.mode		= 0644,
728 		.proc_handler	= proc_dowatchdog_thresh,
729 		.extra1		= &neg_one,
730 		.extra2		= &sixty,
731 	},
732 	{
733 		.procname	= "softlockup_panic",
734 		.data		= &softlockup_panic,
735 		.maxlen		= sizeof(int),
736 		.mode		= 0644,
737 		.proc_handler	= proc_dointvec_minmax,
738 		.extra1		= &zero,
739 		.extra2		= &one,
740 	},
741 #endif
742 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
743 	{
744 		.procname       = "unknown_nmi_panic",
745 		.data           = &unknown_nmi_panic,
746 		.maxlen         = sizeof (int),
747 		.mode           = 0644,
748 		.proc_handler   = proc_dointvec,
749 	},
750 	{
751 		.procname       = "nmi_watchdog",
752 		.data           = &nmi_watchdog_enabled,
753 		.maxlen         = sizeof (int),
754 		.mode           = 0644,
755 		.proc_handler   = proc_nmi_enabled,
756 	},
757 #endif
758 #if defined(CONFIG_X86)
759 	{
760 		.procname	= "panic_on_unrecovered_nmi",
761 		.data		= &panic_on_unrecovered_nmi,
762 		.maxlen		= sizeof(int),
763 		.mode		= 0644,
764 		.proc_handler	= proc_dointvec,
765 	},
766 	{
767 		.procname	= "panic_on_io_nmi",
768 		.data		= &panic_on_io_nmi,
769 		.maxlen		= sizeof(int),
770 		.mode		= 0644,
771 		.proc_handler	= proc_dointvec,
772 	},
773 	{
774 		.procname	= "bootloader_type",
775 		.data		= &bootloader_type,
776 		.maxlen		= sizeof (int),
777 		.mode		= 0444,
778 		.proc_handler	= proc_dointvec,
779 	},
780 	{
781 		.procname	= "bootloader_version",
782 		.data		= &bootloader_version,
783 		.maxlen		= sizeof (int),
784 		.mode		= 0444,
785 		.proc_handler	= proc_dointvec,
786 	},
787 	{
788 		.procname	= "kstack_depth_to_print",
789 		.data		= &kstack_depth_to_print,
790 		.maxlen		= sizeof(int),
791 		.mode		= 0644,
792 		.proc_handler	= proc_dointvec,
793 	},
794 	{
795 		.procname	= "io_delay_type",
796 		.data		= &io_delay_type,
797 		.maxlen		= sizeof(int),
798 		.mode		= 0644,
799 		.proc_handler	= proc_dointvec,
800 	},
801 #endif
802 #if defined(CONFIG_MMU)
803 	{
804 		.procname	= "randomize_va_space",
805 		.data		= &randomize_va_space,
806 		.maxlen		= sizeof(int),
807 		.mode		= 0644,
808 		.proc_handler	= proc_dointvec,
809 	},
810 #endif
811 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
812 	{
813 		.procname	= "spin_retry",
814 		.data		= &spin_retry,
815 		.maxlen		= sizeof (int),
816 		.mode		= 0644,
817 		.proc_handler	= proc_dointvec,
818 	},
819 #endif
820 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
821 	{
822 		.procname	= "acpi_video_flags",
823 		.data		= &acpi_realmode_flags,
824 		.maxlen		= sizeof (unsigned long),
825 		.mode		= 0644,
826 		.proc_handler	= proc_doulongvec_minmax,
827 	},
828 #endif
829 #ifdef CONFIG_IA64
830 	{
831 		.procname	= "ignore-unaligned-usertrap",
832 		.data		= &no_unaligned_warning,
833 		.maxlen		= sizeof (int),
834 	 	.mode		= 0644,
835 		.proc_handler	= proc_dointvec,
836 	},
837 	{
838 		.procname	= "unaligned-dump-stack",
839 		.data		= &unaligned_dump_stack,
840 		.maxlen		= sizeof (int),
841 		.mode		= 0644,
842 		.proc_handler	= proc_dointvec,
843 	},
844 #endif
845 #ifdef CONFIG_DETECT_HUNG_TASK
846 	{
847 		.procname	= "hung_task_panic",
848 		.data		= &sysctl_hung_task_panic,
849 		.maxlen		= sizeof(int),
850 		.mode		= 0644,
851 		.proc_handler	= proc_dointvec_minmax,
852 		.extra1		= &zero,
853 		.extra2		= &one,
854 	},
855 	{
856 		.procname	= "hung_task_check_count",
857 		.data		= &sysctl_hung_task_check_count,
858 		.maxlen		= sizeof(unsigned long),
859 		.mode		= 0644,
860 		.proc_handler	= proc_doulongvec_minmax,
861 	},
862 	{
863 		.procname	= "hung_task_timeout_secs",
864 		.data		= &sysctl_hung_task_timeout_secs,
865 		.maxlen		= sizeof(unsigned long),
866 		.mode		= 0644,
867 		.proc_handler	= proc_dohung_task_timeout_secs,
868 	},
869 	{
870 		.procname	= "hung_task_warnings",
871 		.data		= &sysctl_hung_task_warnings,
872 		.maxlen		= sizeof(unsigned long),
873 		.mode		= 0644,
874 		.proc_handler	= proc_doulongvec_minmax,
875 	},
876 #endif
877 #ifdef CONFIG_COMPAT
878 	{
879 		.procname	= "compat-log",
880 		.data		= &compat_log,
881 		.maxlen		= sizeof (int),
882 	 	.mode		= 0644,
883 		.proc_handler	= proc_dointvec,
884 	},
885 #endif
886 #ifdef CONFIG_RT_MUTEXES
887 	{
888 		.procname	= "max_lock_depth",
889 		.data		= &max_lock_depth,
890 		.maxlen		= sizeof(int),
891 		.mode		= 0644,
892 		.proc_handler	= proc_dointvec,
893 	},
894 #endif
895 	{
896 		.procname	= "poweroff_cmd",
897 		.data		= &poweroff_cmd,
898 		.maxlen		= POWEROFF_CMD_PATH_LEN,
899 		.mode		= 0644,
900 		.proc_handler	= proc_dostring,
901 	},
902 #ifdef CONFIG_KEYS
903 	{
904 		.procname	= "keys",
905 		.mode		= 0555,
906 		.child		= key_sysctls,
907 	},
908 #endif
909 #ifdef CONFIG_RCU_TORTURE_TEST
910 	{
911 		.procname       = "rcutorture_runnable",
912 		.data           = &rcutorture_runnable,
913 		.maxlen         = sizeof(int),
914 		.mode           = 0644,
915 		.proc_handler	= proc_dointvec,
916 	},
917 #endif
918 #ifdef CONFIG_PERF_EVENTS
919 	{
920 		.procname	= "perf_event_paranoid",
921 		.data		= &sysctl_perf_event_paranoid,
922 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
923 		.mode		= 0644,
924 		.proc_handler	= proc_dointvec,
925 	},
926 	{
927 		.procname	= "perf_event_mlock_kb",
928 		.data		= &sysctl_perf_event_mlock,
929 		.maxlen		= sizeof(sysctl_perf_event_mlock),
930 		.mode		= 0644,
931 		.proc_handler	= proc_dointvec,
932 	},
933 	{
934 		.procname	= "perf_event_max_sample_rate",
935 		.data		= &sysctl_perf_event_sample_rate,
936 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
937 		.mode		= 0644,
938 		.proc_handler	= proc_dointvec,
939 	},
940 #endif
941 #ifdef CONFIG_KMEMCHECK
942 	{
943 		.procname	= "kmemcheck",
944 		.data		= &kmemcheck_enabled,
945 		.maxlen		= sizeof(int),
946 		.mode		= 0644,
947 		.proc_handler	= proc_dointvec,
948 	},
949 #endif
950 #ifdef CONFIG_BLOCK
951 	{
952 		.procname	= "blk_iopoll",
953 		.data		= &blk_iopoll_enabled,
954 		.maxlen		= sizeof(int),
955 		.mode		= 0644,
956 		.proc_handler	= proc_dointvec,
957 	},
958 #endif
959 /*
960  * NOTE: do not add new entries to this table unless you have read
961  * Documentation/sysctl/ctl_unnumbered.txt
962  */
963 	{ }
964 };
965 
966 static struct ctl_table vm_table[] = {
967 	{
968 		.procname	= "overcommit_memory",
969 		.data		= &sysctl_overcommit_memory,
970 		.maxlen		= sizeof(sysctl_overcommit_memory),
971 		.mode		= 0644,
972 		.proc_handler	= proc_dointvec,
973 	},
974 	{
975 		.procname	= "panic_on_oom",
976 		.data		= &sysctl_panic_on_oom,
977 		.maxlen		= sizeof(sysctl_panic_on_oom),
978 		.mode		= 0644,
979 		.proc_handler	= proc_dointvec,
980 	},
981 	{
982 		.procname	= "oom_kill_allocating_task",
983 		.data		= &sysctl_oom_kill_allocating_task,
984 		.maxlen		= sizeof(sysctl_oom_kill_allocating_task),
985 		.mode		= 0644,
986 		.proc_handler	= proc_dointvec,
987 	},
988 	{
989 		.procname	= "oom_dump_tasks",
990 		.data		= &sysctl_oom_dump_tasks,
991 		.maxlen		= sizeof(sysctl_oom_dump_tasks),
992 		.mode		= 0644,
993 		.proc_handler	= proc_dointvec,
994 	},
995 	{
996 		.procname	= "overcommit_ratio",
997 		.data		= &sysctl_overcommit_ratio,
998 		.maxlen		= sizeof(sysctl_overcommit_ratio),
999 		.mode		= 0644,
1000 		.proc_handler	= proc_dointvec,
1001 	},
1002 	{
1003 		.procname	= "page-cluster",
1004 		.data		= &page_cluster,
1005 		.maxlen		= sizeof(int),
1006 		.mode		= 0644,
1007 		.proc_handler	= proc_dointvec,
1008 	},
1009 	{
1010 		.procname	= "dirty_background_ratio",
1011 		.data		= &dirty_background_ratio,
1012 		.maxlen		= sizeof(dirty_background_ratio),
1013 		.mode		= 0644,
1014 		.proc_handler	= dirty_background_ratio_handler,
1015 		.extra1		= &zero,
1016 		.extra2		= &one_hundred,
1017 	},
1018 	{
1019 		.procname	= "dirty_background_bytes",
1020 		.data		= &dirty_background_bytes,
1021 		.maxlen		= sizeof(dirty_background_bytes),
1022 		.mode		= 0644,
1023 		.proc_handler	= dirty_background_bytes_handler,
1024 		.extra1		= &one_ul,
1025 	},
1026 	{
1027 		.procname	= "dirty_ratio",
1028 		.data		= &vm_dirty_ratio,
1029 		.maxlen		= sizeof(vm_dirty_ratio),
1030 		.mode		= 0644,
1031 		.proc_handler	= dirty_ratio_handler,
1032 		.extra1		= &zero,
1033 		.extra2		= &one_hundred,
1034 	},
1035 	{
1036 		.procname	= "dirty_bytes",
1037 		.data		= &vm_dirty_bytes,
1038 		.maxlen		= sizeof(vm_dirty_bytes),
1039 		.mode		= 0644,
1040 		.proc_handler	= dirty_bytes_handler,
1041 		.extra1		= &dirty_bytes_min,
1042 	},
1043 	{
1044 		.procname	= "dirty_writeback_centisecs",
1045 		.data		= &dirty_writeback_interval,
1046 		.maxlen		= sizeof(dirty_writeback_interval),
1047 		.mode		= 0644,
1048 		.proc_handler	= dirty_writeback_centisecs_handler,
1049 	},
1050 	{
1051 		.procname	= "dirty_expire_centisecs",
1052 		.data		= &dirty_expire_interval,
1053 		.maxlen		= sizeof(dirty_expire_interval),
1054 		.mode		= 0644,
1055 		.proc_handler	= proc_dointvec,
1056 	},
1057 	{
1058 		.procname	= "nr_pdflush_threads",
1059 		.data		= &nr_pdflush_threads,
1060 		.maxlen		= sizeof nr_pdflush_threads,
1061 		.mode		= 0444 /* read-only*/,
1062 		.proc_handler	= proc_dointvec,
1063 	},
1064 	{
1065 		.procname	= "swappiness",
1066 		.data		= &vm_swappiness,
1067 		.maxlen		= sizeof(vm_swappiness),
1068 		.mode		= 0644,
1069 		.proc_handler	= proc_dointvec_minmax,
1070 		.extra1		= &zero,
1071 		.extra2		= &one_hundred,
1072 	},
1073 #ifdef CONFIG_HUGETLB_PAGE
1074 	{
1075 		.procname	= "nr_hugepages",
1076 		.data		= NULL,
1077 		.maxlen		= sizeof(unsigned long),
1078 		.mode		= 0644,
1079 		.proc_handler	= hugetlb_sysctl_handler,
1080 		.extra1		= (void *)&hugetlb_zero,
1081 		.extra2		= (void *)&hugetlb_infinity,
1082 	},
1083 #ifdef CONFIG_NUMA
1084 	{
1085 		.procname       = "nr_hugepages_mempolicy",
1086 		.data           = NULL,
1087 		.maxlen         = sizeof(unsigned long),
1088 		.mode           = 0644,
1089 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
1090 		.extra1		= (void *)&hugetlb_zero,
1091 		.extra2		= (void *)&hugetlb_infinity,
1092 	},
1093 #endif
1094 	 {
1095 		.procname	= "hugetlb_shm_group",
1096 		.data		= &sysctl_hugetlb_shm_group,
1097 		.maxlen		= sizeof(gid_t),
1098 		.mode		= 0644,
1099 		.proc_handler	= proc_dointvec,
1100 	 },
1101 	 {
1102 		.procname	= "hugepages_treat_as_movable",
1103 		.data		= &hugepages_treat_as_movable,
1104 		.maxlen		= sizeof(int),
1105 		.mode		= 0644,
1106 		.proc_handler	= hugetlb_treat_movable_handler,
1107 	},
1108 	{
1109 		.procname	= "nr_overcommit_hugepages",
1110 		.data		= NULL,
1111 		.maxlen		= sizeof(unsigned long),
1112 		.mode		= 0644,
1113 		.proc_handler	= hugetlb_overcommit_handler,
1114 		.extra1		= (void *)&hugetlb_zero,
1115 		.extra2		= (void *)&hugetlb_infinity,
1116 	},
1117 #endif
1118 	{
1119 		.procname	= "lowmem_reserve_ratio",
1120 		.data		= &sysctl_lowmem_reserve_ratio,
1121 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
1122 		.mode		= 0644,
1123 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
1124 	},
1125 	{
1126 		.procname	= "drop_caches",
1127 		.data		= &sysctl_drop_caches,
1128 		.maxlen		= sizeof(int),
1129 		.mode		= 0644,
1130 		.proc_handler	= drop_caches_sysctl_handler,
1131 	},
1132 #ifdef CONFIG_COMPACTION
1133 	{
1134 		.procname	= "compact_memory",
1135 		.data		= &sysctl_compact_memory,
1136 		.maxlen		= sizeof(int),
1137 		.mode		= 0200,
1138 		.proc_handler	= sysctl_compaction_handler,
1139 	},
1140 	{
1141 		.procname	= "extfrag_threshold",
1142 		.data		= &sysctl_extfrag_threshold,
1143 		.maxlen		= sizeof(int),
1144 		.mode		= 0644,
1145 		.proc_handler	= sysctl_extfrag_handler,
1146 		.extra1		= &min_extfrag_threshold,
1147 		.extra2		= &max_extfrag_threshold,
1148 	},
1149 
1150 #endif /* CONFIG_COMPACTION */
1151 	{
1152 		.procname	= "min_free_kbytes",
1153 		.data		= &min_free_kbytes,
1154 		.maxlen		= sizeof(min_free_kbytes),
1155 		.mode		= 0644,
1156 		.proc_handler	= min_free_kbytes_sysctl_handler,
1157 		.extra1		= &zero,
1158 	},
1159 	{
1160 		.procname	= "percpu_pagelist_fraction",
1161 		.data		= &percpu_pagelist_fraction,
1162 		.maxlen		= sizeof(percpu_pagelist_fraction),
1163 		.mode		= 0644,
1164 		.proc_handler	= percpu_pagelist_fraction_sysctl_handler,
1165 		.extra1		= &min_percpu_pagelist_fract,
1166 	},
1167 #ifdef CONFIG_MMU
1168 	{
1169 		.procname	= "max_map_count",
1170 		.data		= &sysctl_max_map_count,
1171 		.maxlen		= sizeof(sysctl_max_map_count),
1172 		.mode		= 0644,
1173 		.proc_handler	= proc_dointvec_minmax,
1174 		.extra1		= &zero,
1175 	},
1176 #else
1177 	{
1178 		.procname	= "nr_trim_pages",
1179 		.data		= &sysctl_nr_trim_pages,
1180 		.maxlen		= sizeof(sysctl_nr_trim_pages),
1181 		.mode		= 0644,
1182 		.proc_handler	= proc_dointvec_minmax,
1183 		.extra1		= &zero,
1184 	},
1185 #endif
1186 	{
1187 		.procname	= "laptop_mode",
1188 		.data		= &laptop_mode,
1189 		.maxlen		= sizeof(laptop_mode),
1190 		.mode		= 0644,
1191 		.proc_handler	= proc_dointvec_jiffies,
1192 	},
1193 	{
1194 		.procname	= "block_dump",
1195 		.data		= &block_dump,
1196 		.maxlen		= sizeof(block_dump),
1197 		.mode		= 0644,
1198 		.proc_handler	= proc_dointvec,
1199 		.extra1		= &zero,
1200 	},
1201 	{
1202 		.procname	= "vfs_cache_pressure",
1203 		.data		= &sysctl_vfs_cache_pressure,
1204 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
1205 		.mode		= 0644,
1206 		.proc_handler	= proc_dointvec,
1207 		.extra1		= &zero,
1208 	},
1209 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
1210 	{
1211 		.procname	= "legacy_va_layout",
1212 		.data		= &sysctl_legacy_va_layout,
1213 		.maxlen		= sizeof(sysctl_legacy_va_layout),
1214 		.mode		= 0644,
1215 		.proc_handler	= proc_dointvec,
1216 		.extra1		= &zero,
1217 	},
1218 #endif
1219 #ifdef CONFIG_NUMA
1220 	{
1221 		.procname	= "zone_reclaim_mode",
1222 		.data		= &zone_reclaim_mode,
1223 		.maxlen		= sizeof(zone_reclaim_mode),
1224 		.mode		= 0644,
1225 		.proc_handler	= proc_dointvec,
1226 		.extra1		= &zero,
1227 	},
1228 	{
1229 		.procname	= "min_unmapped_ratio",
1230 		.data		= &sysctl_min_unmapped_ratio,
1231 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
1232 		.mode		= 0644,
1233 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
1234 		.extra1		= &zero,
1235 		.extra2		= &one_hundred,
1236 	},
1237 	{
1238 		.procname	= "min_slab_ratio",
1239 		.data		= &sysctl_min_slab_ratio,
1240 		.maxlen		= sizeof(sysctl_min_slab_ratio),
1241 		.mode		= 0644,
1242 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
1243 		.extra1		= &zero,
1244 		.extra2		= &one_hundred,
1245 	},
1246 #endif
1247 #ifdef CONFIG_SMP
1248 	{
1249 		.procname	= "stat_interval",
1250 		.data		= &sysctl_stat_interval,
1251 		.maxlen		= sizeof(sysctl_stat_interval),
1252 		.mode		= 0644,
1253 		.proc_handler	= proc_dointvec_jiffies,
1254 	},
1255 #endif
1256 #ifdef CONFIG_MMU
1257 	{
1258 		.procname	= "mmap_min_addr",
1259 		.data		= &dac_mmap_min_addr,
1260 		.maxlen		= sizeof(unsigned long),
1261 		.mode		= 0644,
1262 		.proc_handler	= mmap_min_addr_handler,
1263 	},
1264 #endif
1265 #ifdef CONFIG_NUMA
1266 	{
1267 		.procname	= "numa_zonelist_order",
1268 		.data		= &numa_zonelist_order,
1269 		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
1270 		.mode		= 0644,
1271 		.proc_handler	= numa_zonelist_order_handler,
1272 	},
1273 #endif
1274 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
1275    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
1276 	{
1277 		.procname	= "vdso_enabled",
1278 		.data		= &vdso_enabled,
1279 		.maxlen		= sizeof(vdso_enabled),
1280 		.mode		= 0644,
1281 		.proc_handler	= proc_dointvec,
1282 		.extra1		= &zero,
1283 	},
1284 #endif
1285 #ifdef CONFIG_HIGHMEM
1286 	{
1287 		.procname	= "highmem_is_dirtyable",
1288 		.data		= &vm_highmem_is_dirtyable,
1289 		.maxlen		= sizeof(vm_highmem_is_dirtyable),
1290 		.mode		= 0644,
1291 		.proc_handler	= proc_dointvec_minmax,
1292 		.extra1		= &zero,
1293 		.extra2		= &one,
1294 	},
1295 #endif
1296 	{
1297 		.procname	= "scan_unevictable_pages",
1298 		.data		= &scan_unevictable_pages,
1299 		.maxlen		= sizeof(scan_unevictable_pages),
1300 		.mode		= 0644,
1301 		.proc_handler	= scan_unevictable_handler,
1302 	},
1303 #ifdef CONFIG_MEMORY_FAILURE
1304 	{
1305 		.procname	= "memory_failure_early_kill",
1306 		.data		= &sysctl_memory_failure_early_kill,
1307 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
1308 		.mode		= 0644,
1309 		.proc_handler	= proc_dointvec_minmax,
1310 		.extra1		= &zero,
1311 		.extra2		= &one,
1312 	},
1313 	{
1314 		.procname	= "memory_failure_recovery",
1315 		.data		= &sysctl_memory_failure_recovery,
1316 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
1317 		.mode		= 0644,
1318 		.proc_handler	= proc_dointvec_minmax,
1319 		.extra1		= &zero,
1320 		.extra2		= &one,
1321 	},
1322 #endif
1323 
1324 /*
1325  * NOTE: do not add new entries to this table unless you have read
1326  * Documentation/sysctl/ctl_unnumbered.txt
1327  */
1328 	{ }
1329 };
1330 
1331 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1332 static struct ctl_table binfmt_misc_table[] = {
1333 	{ }
1334 };
1335 #endif
1336 
1337 static struct ctl_table fs_table[] = {
1338 	{
1339 		.procname	= "inode-nr",
1340 		.data		= &inodes_stat,
1341 		.maxlen		= 2*sizeof(int),
1342 		.mode		= 0444,
1343 		.proc_handler	= proc_dointvec,
1344 	},
1345 	{
1346 		.procname	= "inode-state",
1347 		.data		= &inodes_stat,
1348 		.maxlen		= 7*sizeof(int),
1349 		.mode		= 0444,
1350 		.proc_handler	= proc_dointvec,
1351 	},
1352 	{
1353 		.procname	= "file-nr",
1354 		.data		= &files_stat,
1355 		.maxlen		= 3*sizeof(int),
1356 		.mode		= 0444,
1357 		.proc_handler	= proc_nr_files,
1358 	},
1359 	{
1360 		.procname	= "file-max",
1361 		.data		= &files_stat.max_files,
1362 		.maxlen		= sizeof(int),
1363 		.mode		= 0644,
1364 		.proc_handler	= proc_dointvec,
1365 	},
1366 	{
1367 		.procname	= "nr_open",
1368 		.data		= &sysctl_nr_open,
1369 		.maxlen		= sizeof(int),
1370 		.mode		= 0644,
1371 		.proc_handler	= proc_dointvec_minmax,
1372 		.extra1		= &sysctl_nr_open_min,
1373 		.extra2		= &sysctl_nr_open_max,
1374 	},
1375 	{
1376 		.procname	= "dentry-state",
1377 		.data		= &dentry_stat,
1378 		.maxlen		= 6*sizeof(int),
1379 		.mode		= 0444,
1380 		.proc_handler	= proc_dointvec,
1381 	},
1382 	{
1383 		.procname	= "overflowuid",
1384 		.data		= &fs_overflowuid,
1385 		.maxlen		= sizeof(int),
1386 		.mode		= 0644,
1387 		.proc_handler	= proc_dointvec_minmax,
1388 		.extra1		= &minolduid,
1389 		.extra2		= &maxolduid,
1390 	},
1391 	{
1392 		.procname	= "overflowgid",
1393 		.data		= &fs_overflowgid,
1394 		.maxlen		= sizeof(int),
1395 		.mode		= 0644,
1396 		.proc_handler	= proc_dointvec_minmax,
1397 		.extra1		= &minolduid,
1398 		.extra2		= &maxolduid,
1399 	},
1400 #ifdef CONFIG_FILE_LOCKING
1401 	{
1402 		.procname	= "leases-enable",
1403 		.data		= &leases_enable,
1404 		.maxlen		= sizeof(int),
1405 		.mode		= 0644,
1406 		.proc_handler	= proc_dointvec,
1407 	},
1408 #endif
1409 #ifdef CONFIG_DNOTIFY
1410 	{
1411 		.procname	= "dir-notify-enable",
1412 		.data		= &dir_notify_enable,
1413 		.maxlen		= sizeof(int),
1414 		.mode		= 0644,
1415 		.proc_handler	= proc_dointvec,
1416 	},
1417 #endif
1418 #ifdef CONFIG_MMU
1419 #ifdef CONFIG_FILE_LOCKING
1420 	{
1421 		.procname	= "lease-break-time",
1422 		.data		= &lease_break_time,
1423 		.maxlen		= sizeof(int),
1424 		.mode		= 0644,
1425 		.proc_handler	= proc_dointvec,
1426 	},
1427 #endif
1428 #ifdef CONFIG_AIO
1429 	{
1430 		.procname	= "aio-nr",
1431 		.data		= &aio_nr,
1432 		.maxlen		= sizeof(aio_nr),
1433 		.mode		= 0444,
1434 		.proc_handler	= proc_doulongvec_minmax,
1435 	},
1436 	{
1437 		.procname	= "aio-max-nr",
1438 		.data		= &aio_max_nr,
1439 		.maxlen		= sizeof(aio_max_nr),
1440 		.mode		= 0644,
1441 		.proc_handler	= proc_doulongvec_minmax,
1442 	},
1443 #endif /* CONFIG_AIO */
1444 #ifdef CONFIG_INOTIFY_USER
1445 	{
1446 		.procname	= "inotify",
1447 		.mode		= 0555,
1448 		.child		= inotify_table,
1449 	},
1450 #endif
1451 #ifdef CONFIG_EPOLL
1452 	{
1453 		.procname	= "epoll",
1454 		.mode		= 0555,
1455 		.child		= epoll_table,
1456 	},
1457 #endif
1458 #endif
1459 	{
1460 		.procname	= "suid_dumpable",
1461 		.data		= &suid_dumpable,
1462 		.maxlen		= sizeof(int),
1463 		.mode		= 0644,
1464 		.proc_handler	= proc_dointvec_minmax,
1465 		.extra1		= &zero,
1466 		.extra2		= &two,
1467 	},
1468 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1469 	{
1470 		.procname	= "binfmt_misc",
1471 		.mode		= 0555,
1472 		.child		= binfmt_misc_table,
1473 	},
1474 #endif
1475 	{
1476 		.procname	= "pipe-max-size",
1477 		.data		= &pipe_max_size,
1478 		.maxlen		= sizeof(int),
1479 		.mode		= 0644,
1480 		.proc_handler	= &pipe_proc_fn,
1481 		.extra1		= &pipe_min_size,
1482 	},
1483 /*
1484  * NOTE: do not add new entries to this table unless you have read
1485  * Documentation/sysctl/ctl_unnumbered.txt
1486  */
1487 	{ }
1488 };
1489 
1490 static struct ctl_table debug_table[] = {
1491 #if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_SPARC) || \
1492     defined(CONFIG_S390)
1493 	{
1494 		.procname	= "exception-trace",
1495 		.data		= &show_unhandled_signals,
1496 		.maxlen		= sizeof(int),
1497 		.mode		= 0644,
1498 		.proc_handler	= proc_dointvec
1499 	},
1500 #endif
1501 #if defined(CONFIG_OPTPROBES)
1502 	{
1503 		.procname	= "kprobes-optimization",
1504 		.data		= &sysctl_kprobes_optimization,
1505 		.maxlen		= sizeof(int),
1506 		.mode		= 0644,
1507 		.proc_handler	= proc_kprobes_optimization_handler,
1508 		.extra1		= &zero,
1509 		.extra2		= &one,
1510 	},
1511 #endif
1512 	{ }
1513 };
1514 
1515 static struct ctl_table dev_table[] = {
1516 	{ }
1517 };
1518 
1519 static DEFINE_SPINLOCK(sysctl_lock);
1520 
1521 /* called under sysctl_lock */
1522 static int use_table(struct ctl_table_header *p)
1523 {
1524 	if (unlikely(p->unregistering))
1525 		return 0;
1526 	p->used++;
1527 	return 1;
1528 }
1529 
1530 /* called under sysctl_lock */
1531 static void unuse_table(struct ctl_table_header *p)
1532 {
1533 	if (!--p->used)
1534 		if (unlikely(p->unregistering))
1535 			complete(p->unregistering);
1536 }
1537 
1538 /* called under sysctl_lock, will reacquire if has to wait */
1539 static void start_unregistering(struct ctl_table_header *p)
1540 {
1541 	/*
1542 	 * if p->used is 0, nobody will ever touch that entry again;
1543 	 * we'll eliminate all paths to it before dropping sysctl_lock
1544 	 */
1545 	if (unlikely(p->used)) {
1546 		struct completion wait;
1547 		init_completion(&wait);
1548 		p->unregistering = &wait;
1549 		spin_unlock(&sysctl_lock);
1550 		wait_for_completion(&wait);
1551 		spin_lock(&sysctl_lock);
1552 	} else {
1553 		/* anything non-NULL; we'll never dereference it */
1554 		p->unregistering = ERR_PTR(-EINVAL);
1555 	}
1556 	/*
1557 	 * do not remove from the list until nobody holds it; walking the
1558 	 * list in do_sysctl() relies on that.
1559 	 */
1560 	list_del_init(&p->ctl_entry);
1561 }
1562 
1563 void sysctl_head_get(struct ctl_table_header *head)
1564 {
1565 	spin_lock(&sysctl_lock);
1566 	head->count++;
1567 	spin_unlock(&sysctl_lock);
1568 }
1569 
1570 void sysctl_head_put(struct ctl_table_header *head)
1571 {
1572 	spin_lock(&sysctl_lock);
1573 	if (!--head->count)
1574 		kfree(head);
1575 	spin_unlock(&sysctl_lock);
1576 }
1577 
1578 struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
1579 {
1580 	if (!head)
1581 		BUG();
1582 	spin_lock(&sysctl_lock);
1583 	if (!use_table(head))
1584 		head = ERR_PTR(-ENOENT);
1585 	spin_unlock(&sysctl_lock);
1586 	return head;
1587 }
1588 
1589 void sysctl_head_finish(struct ctl_table_header *head)
1590 {
1591 	if (!head)
1592 		return;
1593 	spin_lock(&sysctl_lock);
1594 	unuse_table(head);
1595 	spin_unlock(&sysctl_lock);
1596 }
1597 
1598 static struct ctl_table_set *
1599 lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
1600 {
1601 	struct ctl_table_set *set = &root->default_set;
1602 	if (root->lookup)
1603 		set = root->lookup(root, namespaces);
1604 	return set;
1605 }
1606 
1607 static struct list_head *
1608 lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
1609 {
1610 	struct ctl_table_set *set = lookup_header_set(root, namespaces);
1611 	return &set->list;
1612 }
1613 
1614 struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
1615 					    struct ctl_table_header *prev)
1616 {
1617 	struct ctl_table_root *root;
1618 	struct list_head *header_list;
1619 	struct ctl_table_header *head;
1620 	struct list_head *tmp;
1621 
1622 	spin_lock(&sysctl_lock);
1623 	if (prev) {
1624 		head = prev;
1625 		tmp = &prev->ctl_entry;
1626 		unuse_table(prev);
1627 		goto next;
1628 	}
1629 	tmp = &root_table_header.ctl_entry;
1630 	for (;;) {
1631 		head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1632 
1633 		if (!use_table(head))
1634 			goto next;
1635 		spin_unlock(&sysctl_lock);
1636 		return head;
1637 	next:
1638 		root = head->root;
1639 		tmp = tmp->next;
1640 		header_list = lookup_header_list(root, namespaces);
1641 		if (tmp != header_list)
1642 			continue;
1643 
1644 		do {
1645 			root = list_entry(root->root_list.next,
1646 					struct ctl_table_root, root_list);
1647 			if (root == &sysctl_table_root)
1648 				goto out;
1649 			header_list = lookup_header_list(root, namespaces);
1650 		} while (list_empty(header_list));
1651 		tmp = header_list->next;
1652 	}
1653 out:
1654 	spin_unlock(&sysctl_lock);
1655 	return NULL;
1656 }
1657 
1658 struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1659 {
1660 	return __sysctl_head_next(current->nsproxy, prev);
1661 }
1662 
1663 void register_sysctl_root(struct ctl_table_root *root)
1664 {
1665 	spin_lock(&sysctl_lock);
1666 	list_add_tail(&root->root_list, &sysctl_table_root.root_list);
1667 	spin_unlock(&sysctl_lock);
1668 }
1669 
1670 /*
1671  * sysctl_perm does NOT grant the superuser all rights automatically, because
1672  * some sysctl variables are readonly even to root.
1673  */
1674 
1675 static int test_perm(int mode, int op)
1676 {
1677 	if (!current_euid())
1678 		mode >>= 6;
1679 	else if (in_egroup_p(0))
1680 		mode >>= 3;
1681 	if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
1682 		return 0;
1683 	return -EACCES;
1684 }
1685 
1686 int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
1687 {
1688 	int error;
1689 	int mode;
1690 
1691 	error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
1692 	if (error)
1693 		return error;
1694 
1695 	if (root->permissions)
1696 		mode = root->permissions(root, current->nsproxy, table);
1697 	else
1698 		mode = table->mode;
1699 
1700 	return test_perm(mode, op);
1701 }
1702 
1703 static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1704 {
1705 	for (; table->procname; table++) {
1706 		table->parent = parent;
1707 		if (table->child)
1708 			sysctl_set_parent(table, table->child);
1709 	}
1710 }
1711 
1712 static __init int sysctl_init(void)
1713 {
1714 	sysctl_set_parent(NULL, root_table);
1715 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1716 	{
1717 		int err;
1718 		err = sysctl_check_table(current->nsproxy, root_table);
1719 	}
1720 #endif
1721 	return 0;
1722 }
1723 
1724 core_initcall(sysctl_init);
1725 
1726 static struct ctl_table *is_branch_in(struct ctl_table *branch,
1727 				      struct ctl_table *table)
1728 {
1729 	struct ctl_table *p;
1730 	const char *s = branch->procname;
1731 
1732 	/* branch should have named subdirectory as its first element */
1733 	if (!s || !branch->child)
1734 		return NULL;
1735 
1736 	/* ... and nothing else */
1737 	if (branch[1].procname)
1738 		return NULL;
1739 
1740 	/* table should contain subdirectory with the same name */
1741 	for (p = table; p->procname; p++) {
1742 		if (!p->child)
1743 			continue;
1744 		if (p->procname && strcmp(p->procname, s) == 0)
1745 			return p;
1746 	}
1747 	return NULL;
1748 }
1749 
1750 /* see if attaching q to p would be an improvement */
1751 static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
1752 {
1753 	struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
1754 	struct ctl_table *next;
1755 	int is_better = 0;
1756 	int not_in_parent = !p->attached_by;
1757 
1758 	while ((next = is_branch_in(by, to)) != NULL) {
1759 		if (by == q->attached_by)
1760 			is_better = 1;
1761 		if (to == p->attached_by)
1762 			not_in_parent = 1;
1763 		by = by->child;
1764 		to = next->child;
1765 	}
1766 
1767 	if (is_better && not_in_parent) {
1768 		q->attached_by = by;
1769 		q->attached_to = to;
1770 		q->parent = p;
1771 	}
1772 }
1773 
1774 /**
1775  * __register_sysctl_paths - register a sysctl hierarchy
1776  * @root: List of sysctl headers to register on
1777  * @namespaces: Data to compute which lists of sysctl entries are visible
1778  * @path: The path to the directory the sysctl table is in.
1779  * @table: the top-level table structure
1780  *
1781  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1782  * array. A completely 0 filled entry terminates the table.
1783  *
1784  * The members of the &struct ctl_table structure are used as follows:
1785  *
1786  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1787  *            enter a sysctl file
1788  *
1789  * data - a pointer to data for use by proc_handler
1790  *
1791  * maxlen - the maximum size in bytes of the data
1792  *
1793  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1794  *
1795  * child - a pointer to the child sysctl table if this entry is a directory, or
1796  *         %NULL.
1797  *
1798  * proc_handler - the text handler routine (described below)
1799  *
1800  * de - for internal use by the sysctl routines
1801  *
1802  * extra1, extra2 - extra pointers usable by the proc handler routines
1803  *
1804  * Leaf nodes in the sysctl tree will be represented by a single file
1805  * under /proc; non-leaf nodes will be represented by directories.
1806  *
1807  * sysctl(2) can automatically manage read and write requests through
1808  * the sysctl table.  The data and maxlen fields of the ctl_table
1809  * struct enable minimal validation of the values being written to be
1810  * performed, and the mode field allows minimal authentication.
1811  *
1812  * There must be a proc_handler routine for any terminal nodes
1813  * mirrored under /proc/sys (non-terminals are handled by a built-in
1814  * directory handler).  Several default handlers are available to
1815  * cover common cases -
1816  *
1817  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1818  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1819  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1820  *
1821  * It is the handler's job to read the input buffer from user memory
1822  * and process it. The handler should return 0 on success.
1823  *
1824  * This routine returns %NULL on a failure to register, and a pointer
1825  * to the table header on success.
1826  */
1827 struct ctl_table_header *__register_sysctl_paths(
1828 	struct ctl_table_root *root,
1829 	struct nsproxy *namespaces,
1830 	const struct ctl_path *path, struct ctl_table *table)
1831 {
1832 	struct ctl_table_header *header;
1833 	struct ctl_table *new, **prevp;
1834 	unsigned int n, npath;
1835 	struct ctl_table_set *set;
1836 
1837 	/* Count the path components */
1838 	for (npath = 0; path[npath].procname; ++npath)
1839 		;
1840 
1841 	/*
1842 	 * For each path component, allocate a 2-element ctl_table array.
1843 	 * The first array element will be filled with the sysctl entry
1844 	 * for this, the second will be the sentinel (procname == 0).
1845 	 *
1846 	 * We allocate everything in one go so that we don't have to
1847 	 * worry about freeing additional memory in unregister_sysctl_table.
1848 	 */
1849 	header = kzalloc(sizeof(struct ctl_table_header) +
1850 			 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
1851 	if (!header)
1852 		return NULL;
1853 
1854 	new = (struct ctl_table *) (header + 1);
1855 
1856 	/* Now connect the dots */
1857 	prevp = &header->ctl_table;
1858 	for (n = 0; n < npath; ++n, ++path) {
1859 		/* Copy the procname */
1860 		new->procname = path->procname;
1861 		new->mode     = 0555;
1862 
1863 		*prevp = new;
1864 		prevp = &new->child;
1865 
1866 		new += 2;
1867 	}
1868 	*prevp = table;
1869 	header->ctl_table_arg = table;
1870 
1871 	INIT_LIST_HEAD(&header->ctl_entry);
1872 	header->used = 0;
1873 	header->unregistering = NULL;
1874 	header->root = root;
1875 	sysctl_set_parent(NULL, header->ctl_table);
1876 	header->count = 1;
1877 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1878 	if (sysctl_check_table(namespaces, header->ctl_table)) {
1879 		kfree(header);
1880 		return NULL;
1881 	}
1882 #endif
1883 	spin_lock(&sysctl_lock);
1884 	header->set = lookup_header_set(root, namespaces);
1885 	header->attached_by = header->ctl_table;
1886 	header->attached_to = root_table;
1887 	header->parent = &root_table_header;
1888 	for (set = header->set; set; set = set->parent) {
1889 		struct ctl_table_header *p;
1890 		list_for_each_entry(p, &set->list, ctl_entry) {
1891 			if (p->unregistering)
1892 				continue;
1893 			try_attach(p, header);
1894 		}
1895 	}
1896 	header->parent->count++;
1897 	list_add_tail(&header->ctl_entry, &header->set->list);
1898 	spin_unlock(&sysctl_lock);
1899 
1900 	return header;
1901 }
1902 
1903 /**
1904  * register_sysctl_table_path - register a sysctl table hierarchy
1905  * @path: The path to the directory the sysctl table is in.
1906  * @table: the top-level table structure
1907  *
1908  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1909  * array. A completely 0 filled entry terminates the table.
1910  *
1911  * See __register_sysctl_paths for more details.
1912  */
1913 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1914 						struct ctl_table *table)
1915 {
1916 	return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1917 					path, table);
1918 }
1919 
1920 /**
1921  * register_sysctl_table - register a sysctl table hierarchy
1922  * @table: the top-level table structure
1923  *
1924  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1925  * array. A completely 0 filled entry terminates the table.
1926  *
1927  * See register_sysctl_paths for more details.
1928  */
1929 struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1930 {
1931 	static const struct ctl_path null_path[] = { {} };
1932 
1933 	return register_sysctl_paths(null_path, table);
1934 }
1935 
1936 /**
1937  * unregister_sysctl_table - unregister a sysctl table hierarchy
1938  * @header: the header returned from register_sysctl_table
1939  *
1940  * Unregisters the sysctl table and all children. proc entries may not
1941  * actually be removed until they are no longer used by anyone.
1942  */
1943 void unregister_sysctl_table(struct ctl_table_header * header)
1944 {
1945 	might_sleep();
1946 
1947 	if (header == NULL)
1948 		return;
1949 
1950 	spin_lock(&sysctl_lock);
1951 	start_unregistering(header);
1952 	if (!--header->parent->count) {
1953 		WARN_ON(1);
1954 		kfree(header->parent);
1955 	}
1956 	if (!--header->count)
1957 		kfree(header);
1958 	spin_unlock(&sysctl_lock);
1959 }
1960 
1961 int sysctl_is_seen(struct ctl_table_header *p)
1962 {
1963 	struct ctl_table_set *set = p->set;
1964 	int res;
1965 	spin_lock(&sysctl_lock);
1966 	if (p->unregistering)
1967 		res = 0;
1968 	else if (!set->is_seen)
1969 		res = 1;
1970 	else
1971 		res = set->is_seen(set);
1972 	spin_unlock(&sysctl_lock);
1973 	return res;
1974 }
1975 
1976 void setup_sysctl_set(struct ctl_table_set *p,
1977 	struct ctl_table_set *parent,
1978 	int (*is_seen)(struct ctl_table_set *))
1979 {
1980 	INIT_LIST_HEAD(&p->list);
1981 	p->parent = parent ? parent : &sysctl_table_root.default_set;
1982 	p->is_seen = is_seen;
1983 }
1984 
1985 #else /* !CONFIG_SYSCTL */
1986 struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
1987 {
1988 	return NULL;
1989 }
1990 
1991 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1992 						    struct ctl_table *table)
1993 {
1994 	return NULL;
1995 }
1996 
1997 void unregister_sysctl_table(struct ctl_table_header * table)
1998 {
1999 }
2000 
2001 void setup_sysctl_set(struct ctl_table_set *p,
2002 	struct ctl_table_set *parent,
2003 	int (*is_seen)(struct ctl_table_set *))
2004 {
2005 }
2006 
2007 void sysctl_head_put(struct ctl_table_header *head)
2008 {
2009 }
2010 
2011 #endif /* CONFIG_SYSCTL */
2012 
2013 /*
2014  * /proc/sys support
2015  */
2016 
2017 #ifdef CONFIG_PROC_SYSCTL
2018 
2019 static int _proc_do_string(void* data, int maxlen, int write,
2020 			   void __user *buffer,
2021 			   size_t *lenp, loff_t *ppos)
2022 {
2023 	size_t len;
2024 	char __user *p;
2025 	char c;
2026 
2027 	if (!data || !maxlen || !*lenp) {
2028 		*lenp = 0;
2029 		return 0;
2030 	}
2031 
2032 	if (write) {
2033 		len = 0;
2034 		p = buffer;
2035 		while (len < *lenp) {
2036 			if (get_user(c, p++))
2037 				return -EFAULT;
2038 			if (c == 0 || c == '\n')
2039 				break;
2040 			len++;
2041 		}
2042 		if (len >= maxlen)
2043 			len = maxlen-1;
2044 		if(copy_from_user(data, buffer, len))
2045 			return -EFAULT;
2046 		((char *) data)[len] = 0;
2047 		*ppos += *lenp;
2048 	} else {
2049 		len = strlen(data);
2050 		if (len > maxlen)
2051 			len = maxlen;
2052 
2053 		if (*ppos > len) {
2054 			*lenp = 0;
2055 			return 0;
2056 		}
2057 
2058 		data += *ppos;
2059 		len  -= *ppos;
2060 
2061 		if (len > *lenp)
2062 			len = *lenp;
2063 		if (len)
2064 			if(copy_to_user(buffer, data, len))
2065 				return -EFAULT;
2066 		if (len < *lenp) {
2067 			if(put_user('\n', ((char __user *) buffer) + len))
2068 				return -EFAULT;
2069 			len++;
2070 		}
2071 		*lenp = len;
2072 		*ppos += len;
2073 	}
2074 	return 0;
2075 }
2076 
2077 /**
2078  * proc_dostring - read a string sysctl
2079  * @table: the sysctl table
2080  * @write: %TRUE if this is a write to the sysctl file
2081  * @buffer: the user buffer
2082  * @lenp: the size of the user buffer
2083  * @ppos: file position
2084  *
2085  * Reads/writes a string from/to the user buffer. If the kernel
2086  * buffer provided is not large enough to hold the string, the
2087  * string is truncated. The copied string is %NULL-terminated.
2088  * If the string is being read by the user process, it is copied
2089  * and a newline '\n' is added. It is truncated if the buffer is
2090  * not large enough.
2091  *
2092  * Returns 0 on success.
2093  */
2094 int proc_dostring(struct ctl_table *table, int write,
2095 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2096 {
2097 	return _proc_do_string(table->data, table->maxlen, write,
2098 			       buffer, lenp, ppos);
2099 }
2100 
2101 static size_t proc_skip_spaces(char **buf)
2102 {
2103 	size_t ret;
2104 	char *tmp = skip_spaces(*buf);
2105 	ret = tmp - *buf;
2106 	*buf = tmp;
2107 	return ret;
2108 }
2109 
2110 static void proc_skip_char(char **buf, size_t *size, const char v)
2111 {
2112 	while (*size) {
2113 		if (**buf != v)
2114 			break;
2115 		(*size)--;
2116 		(*buf)++;
2117 	}
2118 }
2119 
2120 #define TMPBUFLEN 22
2121 /**
2122  * proc_get_long - reads an ASCII formatted integer from a user buffer
2123  *
2124  * @buf: a kernel buffer
2125  * @size: size of the kernel buffer
2126  * @val: this is where the number will be stored
2127  * @neg: set to %TRUE if number is negative
2128  * @perm_tr: a vector which contains the allowed trailers
2129  * @perm_tr_len: size of the perm_tr vector
2130  * @tr: pointer to store the trailer character
2131  *
2132  * In case of success %0 is returned and @buf and @size are updated with
2133  * the amount of bytes read. If @tr is non-NULL and a trailing
2134  * character exists (size is non-zero after returning from this
2135  * function), @tr is updated with the trailing character.
2136  */
2137 static int proc_get_long(char **buf, size_t *size,
2138 			  unsigned long *val, bool *neg,
2139 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
2140 {
2141 	int len;
2142 	char *p, tmp[TMPBUFLEN];
2143 
2144 	if (!*size)
2145 		return -EINVAL;
2146 
2147 	len = *size;
2148 	if (len > TMPBUFLEN - 1)
2149 		len = TMPBUFLEN - 1;
2150 
2151 	memcpy(tmp, *buf, len);
2152 
2153 	tmp[len] = 0;
2154 	p = tmp;
2155 	if (*p == '-' && *size > 1) {
2156 		*neg = true;
2157 		p++;
2158 	} else
2159 		*neg = false;
2160 	if (!isdigit(*p))
2161 		return -EINVAL;
2162 
2163 	*val = simple_strtoul(p, &p, 0);
2164 
2165 	len = p - tmp;
2166 
2167 	/* We don't know if the next char is whitespace thus we may accept
2168 	 * invalid integers (e.g. 1234...a) or two integers instead of one
2169 	 * (e.g. 123...1). So lets not allow such large numbers. */
2170 	if (len == TMPBUFLEN - 1)
2171 		return -EINVAL;
2172 
2173 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
2174 		return -EINVAL;
2175 
2176 	if (tr && (len < *size))
2177 		*tr = *p;
2178 
2179 	*buf += len;
2180 	*size -= len;
2181 
2182 	return 0;
2183 }
2184 
2185 /**
2186  * proc_put_long - converts an integer to a decimal ASCII formatted string
2187  *
2188  * @buf: the user buffer
2189  * @size: the size of the user buffer
2190  * @val: the integer to be converted
2191  * @neg: sign of the number, %TRUE for negative
2192  *
2193  * In case of success %0 is returned and @buf and @size are updated with
2194  * the amount of bytes written.
2195  */
2196 static int proc_put_long(void __user **buf, size_t *size, unsigned long val,
2197 			  bool neg)
2198 {
2199 	int len;
2200 	char tmp[TMPBUFLEN], *p = tmp;
2201 
2202 	sprintf(p, "%s%lu", neg ? "-" : "", val);
2203 	len = strlen(tmp);
2204 	if (len > *size)
2205 		len = *size;
2206 	if (copy_to_user(*buf, tmp, len))
2207 		return -EFAULT;
2208 	*size -= len;
2209 	*buf += len;
2210 	return 0;
2211 }
2212 #undef TMPBUFLEN
2213 
2214 static int proc_put_char(void __user **buf, size_t *size, char c)
2215 {
2216 	if (*size) {
2217 		char __user **buffer = (char __user **)buf;
2218 		if (put_user(c, *buffer))
2219 			return -EFAULT;
2220 		(*size)--, (*buffer)++;
2221 		*buf = *buffer;
2222 	}
2223 	return 0;
2224 }
2225 
2226 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
2227 				 int *valp,
2228 				 int write, void *data)
2229 {
2230 	if (write) {
2231 		*valp = *negp ? -*lvalp : *lvalp;
2232 	} else {
2233 		int val = *valp;
2234 		if (val < 0) {
2235 			*negp = true;
2236 			*lvalp = (unsigned long)-val;
2237 		} else {
2238 			*negp = false;
2239 			*lvalp = (unsigned long)val;
2240 		}
2241 	}
2242 	return 0;
2243 }
2244 
2245 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
2246 
2247 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
2248 		  int write, void __user *buffer,
2249 		  size_t *lenp, loff_t *ppos,
2250 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2251 			      int write, void *data),
2252 		  void *data)
2253 {
2254 	int *i, vleft, first = 1, err = 0;
2255 	unsigned long page = 0;
2256 	size_t left;
2257 	char *kbuf;
2258 
2259 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
2260 		*lenp = 0;
2261 		return 0;
2262 	}
2263 
2264 	i = (int *) tbl_data;
2265 	vleft = table->maxlen / sizeof(*i);
2266 	left = *lenp;
2267 
2268 	if (!conv)
2269 		conv = do_proc_dointvec_conv;
2270 
2271 	if (write) {
2272 		if (left > PAGE_SIZE - 1)
2273 			left = PAGE_SIZE - 1;
2274 		page = __get_free_page(GFP_TEMPORARY);
2275 		kbuf = (char *) page;
2276 		if (!kbuf)
2277 			return -ENOMEM;
2278 		if (copy_from_user(kbuf, buffer, left)) {
2279 			err = -EFAULT;
2280 			goto free;
2281 		}
2282 		kbuf[left] = 0;
2283 	}
2284 
2285 	for (; left && vleft--; i++, first=0) {
2286 		unsigned long lval;
2287 		bool neg;
2288 
2289 		if (write) {
2290 			left -= proc_skip_spaces(&kbuf);
2291 
2292 			if (!left)
2293 				break;
2294 			err = proc_get_long(&kbuf, &left, &lval, &neg,
2295 					     proc_wspace_sep,
2296 					     sizeof(proc_wspace_sep), NULL);
2297 			if (err)
2298 				break;
2299 			if (conv(&neg, &lval, i, 1, data)) {
2300 				err = -EINVAL;
2301 				break;
2302 			}
2303 		} else {
2304 			if (conv(&neg, &lval, i, 0, data)) {
2305 				err = -EINVAL;
2306 				break;
2307 			}
2308 			if (!first)
2309 				err = proc_put_char(&buffer, &left, '\t');
2310 			if (err)
2311 				break;
2312 			err = proc_put_long(&buffer, &left, lval, neg);
2313 			if (err)
2314 				break;
2315 		}
2316 	}
2317 
2318 	if (!write && !first && left && !err)
2319 		err = proc_put_char(&buffer, &left, '\n');
2320 	if (write && !err && left)
2321 		left -= proc_skip_spaces(&kbuf);
2322 free:
2323 	if (write) {
2324 		free_page(page);
2325 		if (first)
2326 			return err ? : -EINVAL;
2327 	}
2328 	*lenp -= left;
2329 	*ppos += *lenp;
2330 	return err;
2331 }
2332 
2333 static int do_proc_dointvec(struct ctl_table *table, int write,
2334 		  void __user *buffer, size_t *lenp, loff_t *ppos,
2335 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2336 			      int write, void *data),
2337 		  void *data)
2338 {
2339 	return __do_proc_dointvec(table->data, table, write,
2340 			buffer, lenp, ppos, conv, data);
2341 }
2342 
2343 /**
2344  * proc_dointvec - read a vector of integers
2345  * @table: the sysctl table
2346  * @write: %TRUE if this is a write to the sysctl file
2347  * @buffer: the user buffer
2348  * @lenp: the size of the user buffer
2349  * @ppos: file position
2350  *
2351  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2352  * values from/to the user buffer, treated as an ASCII string.
2353  *
2354  * Returns 0 on success.
2355  */
2356 int proc_dointvec(struct ctl_table *table, int write,
2357 		     void __user *buffer, size_t *lenp, loff_t *ppos)
2358 {
2359     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2360 		    	    NULL,NULL);
2361 }
2362 
2363 /*
2364  * Taint values can only be increased
2365  * This means we can safely use a temporary.
2366  */
2367 static int proc_taint(struct ctl_table *table, int write,
2368 			       void __user *buffer, size_t *lenp, loff_t *ppos)
2369 {
2370 	struct ctl_table t;
2371 	unsigned long tmptaint = get_taint();
2372 	int err;
2373 
2374 	if (write && !capable(CAP_SYS_ADMIN))
2375 		return -EPERM;
2376 
2377 	t = *table;
2378 	t.data = &tmptaint;
2379 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
2380 	if (err < 0)
2381 		return err;
2382 
2383 	if (write) {
2384 		/*
2385 		 * Poor man's atomic or. Not worth adding a primitive
2386 		 * to everyone's atomic.h for this
2387 		 */
2388 		int i;
2389 		for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
2390 			if ((tmptaint >> i) & 1)
2391 				add_taint(i);
2392 		}
2393 	}
2394 
2395 	return err;
2396 }
2397 
2398 struct do_proc_dointvec_minmax_conv_param {
2399 	int *min;
2400 	int *max;
2401 };
2402 
2403 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
2404 					int *valp,
2405 					int write, void *data)
2406 {
2407 	struct do_proc_dointvec_minmax_conv_param *param = data;
2408 	if (write) {
2409 		int val = *negp ? -*lvalp : *lvalp;
2410 		if ((param->min && *param->min > val) ||
2411 		    (param->max && *param->max < val))
2412 			return -EINVAL;
2413 		*valp = val;
2414 	} else {
2415 		int val = *valp;
2416 		if (val < 0) {
2417 			*negp = true;
2418 			*lvalp = (unsigned long)-val;
2419 		} else {
2420 			*negp = false;
2421 			*lvalp = (unsigned long)val;
2422 		}
2423 	}
2424 	return 0;
2425 }
2426 
2427 /**
2428  * proc_dointvec_minmax - read a vector of integers with min/max values
2429  * @table: the sysctl table
2430  * @write: %TRUE if this is a write to the sysctl file
2431  * @buffer: the user buffer
2432  * @lenp: the size of the user buffer
2433  * @ppos: file position
2434  *
2435  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2436  * values from/to the user buffer, treated as an ASCII string.
2437  *
2438  * This routine will ensure the values are within the range specified by
2439  * table->extra1 (min) and table->extra2 (max).
2440  *
2441  * Returns 0 on success.
2442  */
2443 int proc_dointvec_minmax(struct ctl_table *table, int write,
2444 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2445 {
2446 	struct do_proc_dointvec_minmax_conv_param param = {
2447 		.min = (int *) table->extra1,
2448 		.max = (int *) table->extra2,
2449 	};
2450 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2451 				do_proc_dointvec_minmax_conv, &param);
2452 }
2453 
2454 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
2455 				     void __user *buffer,
2456 				     size_t *lenp, loff_t *ppos,
2457 				     unsigned long convmul,
2458 				     unsigned long convdiv)
2459 {
2460 	unsigned long *i, *min, *max;
2461 	int vleft, first = 1, err = 0;
2462 	unsigned long page = 0;
2463 	size_t left;
2464 	char *kbuf;
2465 
2466 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
2467 		*lenp = 0;
2468 		return 0;
2469 	}
2470 
2471 	i = (unsigned long *) data;
2472 	min = (unsigned long *) table->extra1;
2473 	max = (unsigned long *) table->extra2;
2474 	vleft = table->maxlen / sizeof(unsigned long);
2475 	left = *lenp;
2476 
2477 	if (write) {
2478 		if (left > PAGE_SIZE - 1)
2479 			left = PAGE_SIZE - 1;
2480 		page = __get_free_page(GFP_TEMPORARY);
2481 		kbuf = (char *) page;
2482 		if (!kbuf)
2483 			return -ENOMEM;
2484 		if (copy_from_user(kbuf, buffer, left)) {
2485 			err = -EFAULT;
2486 			goto free;
2487 		}
2488 		kbuf[left] = 0;
2489 	}
2490 
2491 	for (; left && vleft--; i++, min++, max++, first=0) {
2492 		unsigned long val;
2493 
2494 		if (write) {
2495 			bool neg;
2496 
2497 			left -= proc_skip_spaces(&kbuf);
2498 
2499 			err = proc_get_long(&kbuf, &left, &val, &neg,
2500 					     proc_wspace_sep,
2501 					     sizeof(proc_wspace_sep), NULL);
2502 			if (err)
2503 				break;
2504 			if (neg)
2505 				continue;
2506 			if ((min && val < *min) || (max && val > *max))
2507 				continue;
2508 			*i = val;
2509 		} else {
2510 			val = convdiv * (*i) / convmul;
2511 			if (!first)
2512 				err = proc_put_char(&buffer, &left, '\t');
2513 			err = proc_put_long(&buffer, &left, val, false);
2514 			if (err)
2515 				break;
2516 		}
2517 	}
2518 
2519 	if (!write && !first && left && !err)
2520 		err = proc_put_char(&buffer, &left, '\n');
2521 	if (write && !err)
2522 		left -= proc_skip_spaces(&kbuf);
2523 free:
2524 	if (write) {
2525 		free_page(page);
2526 		if (first)
2527 			return err ? : -EINVAL;
2528 	}
2529 	*lenp -= left;
2530 	*ppos += *lenp;
2531 	return err;
2532 }
2533 
2534 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
2535 				     void __user *buffer,
2536 				     size_t *lenp, loff_t *ppos,
2537 				     unsigned long convmul,
2538 				     unsigned long convdiv)
2539 {
2540 	return __do_proc_doulongvec_minmax(table->data, table, write,
2541 			buffer, lenp, ppos, convmul, convdiv);
2542 }
2543 
2544 /**
2545  * proc_doulongvec_minmax - read a vector of long integers with min/max values
2546  * @table: the sysctl table
2547  * @write: %TRUE if this is a write to the sysctl file
2548  * @buffer: the user buffer
2549  * @lenp: the size of the user buffer
2550  * @ppos: file position
2551  *
2552  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2553  * values from/to the user buffer, treated as an ASCII string.
2554  *
2555  * This routine will ensure the values are within the range specified by
2556  * table->extra1 (min) and table->extra2 (max).
2557  *
2558  * Returns 0 on success.
2559  */
2560 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2561 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2562 {
2563     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
2564 }
2565 
2566 /**
2567  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2568  * @table: the sysctl table
2569  * @write: %TRUE if this is a write to the sysctl file
2570  * @buffer: the user buffer
2571  * @lenp: the size of the user buffer
2572  * @ppos: file position
2573  *
2574  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2575  * values from/to the user buffer, treated as an ASCII string. The values
2576  * are treated as milliseconds, and converted to jiffies when they are stored.
2577  *
2578  * This routine will ensure the values are within the range specified by
2579  * table->extra1 (min) and table->extra2 (max).
2580  *
2581  * Returns 0 on success.
2582  */
2583 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2584 				      void __user *buffer,
2585 				      size_t *lenp, loff_t *ppos)
2586 {
2587     return do_proc_doulongvec_minmax(table, write, buffer,
2588 				     lenp, ppos, HZ, 1000l);
2589 }
2590 
2591 
2592 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
2593 					 int *valp,
2594 					 int write, void *data)
2595 {
2596 	if (write) {
2597 		if (*lvalp > LONG_MAX / HZ)
2598 			return 1;
2599 		*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2600 	} else {
2601 		int val = *valp;
2602 		unsigned long lval;
2603 		if (val < 0) {
2604 			*negp = true;
2605 			lval = (unsigned long)-val;
2606 		} else {
2607 			*negp = false;
2608 			lval = (unsigned long)val;
2609 		}
2610 		*lvalp = lval / HZ;
2611 	}
2612 	return 0;
2613 }
2614 
2615 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
2616 						int *valp,
2617 						int write, void *data)
2618 {
2619 	if (write) {
2620 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2621 			return 1;
2622 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2623 	} else {
2624 		int val = *valp;
2625 		unsigned long lval;
2626 		if (val < 0) {
2627 			*negp = true;
2628 			lval = (unsigned long)-val;
2629 		} else {
2630 			*negp = false;
2631 			lval = (unsigned long)val;
2632 		}
2633 		*lvalp = jiffies_to_clock_t(lval);
2634 	}
2635 	return 0;
2636 }
2637 
2638 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
2639 					    int *valp,
2640 					    int write, void *data)
2641 {
2642 	if (write) {
2643 		*valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2644 	} else {
2645 		int val = *valp;
2646 		unsigned long lval;
2647 		if (val < 0) {
2648 			*negp = true;
2649 			lval = (unsigned long)-val;
2650 		} else {
2651 			*negp = false;
2652 			lval = (unsigned long)val;
2653 		}
2654 		*lvalp = jiffies_to_msecs(lval);
2655 	}
2656 	return 0;
2657 }
2658 
2659 /**
2660  * proc_dointvec_jiffies - read a vector of integers as seconds
2661  * @table: the sysctl table
2662  * @write: %TRUE if this is a write to the sysctl file
2663  * @buffer: the user buffer
2664  * @lenp: the size of the user buffer
2665  * @ppos: file position
2666  *
2667  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2668  * values from/to the user buffer, treated as an ASCII string.
2669  * The values read are assumed to be in seconds, and are converted into
2670  * jiffies.
2671  *
2672  * Returns 0 on success.
2673  */
2674 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2675 			  void __user *buffer, size_t *lenp, loff_t *ppos)
2676 {
2677     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2678 		    	    do_proc_dointvec_jiffies_conv,NULL);
2679 }
2680 
2681 /**
2682  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2683  * @table: the sysctl table
2684  * @write: %TRUE if this is a write to the sysctl file
2685  * @buffer: the user buffer
2686  * @lenp: the size of the user buffer
2687  * @ppos: pointer to the file position
2688  *
2689  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2690  * values from/to the user buffer, treated as an ASCII string.
2691  * The values read are assumed to be in 1/USER_HZ seconds, and
2692  * are converted into jiffies.
2693  *
2694  * Returns 0 on success.
2695  */
2696 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2697 				 void __user *buffer, size_t *lenp, loff_t *ppos)
2698 {
2699     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2700 		    	    do_proc_dointvec_userhz_jiffies_conv,NULL);
2701 }
2702 
2703 /**
2704  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2705  * @table: the sysctl table
2706  * @write: %TRUE if this is a write to the sysctl file
2707  * @buffer: the user buffer
2708  * @lenp: the size of the user buffer
2709  * @ppos: file position
2710  * @ppos: the current position in the file
2711  *
2712  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2713  * values from/to the user buffer, treated as an ASCII string.
2714  * The values read are assumed to be in 1/1000 seconds, and
2715  * are converted into jiffies.
2716  *
2717  * Returns 0 on success.
2718  */
2719 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2720 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2721 {
2722 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2723 				do_proc_dointvec_ms_jiffies_conv, NULL);
2724 }
2725 
2726 static int proc_do_cad_pid(struct ctl_table *table, int write,
2727 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2728 {
2729 	struct pid *new_pid;
2730 	pid_t tmp;
2731 	int r;
2732 
2733 	tmp = pid_vnr(cad_pid);
2734 
2735 	r = __do_proc_dointvec(&tmp, table, write, buffer,
2736 			       lenp, ppos, NULL, NULL);
2737 	if (r || !write)
2738 		return r;
2739 
2740 	new_pid = find_get_pid(tmp);
2741 	if (!new_pid)
2742 		return -ESRCH;
2743 
2744 	put_pid(xchg(&cad_pid, new_pid));
2745 	return 0;
2746 }
2747 
2748 /**
2749  * proc_do_large_bitmap - read/write from/to a large bitmap
2750  * @table: the sysctl table
2751  * @write: %TRUE if this is a write to the sysctl file
2752  * @buffer: the user buffer
2753  * @lenp: the size of the user buffer
2754  * @ppos: file position
2755  *
2756  * The bitmap is stored at table->data and the bitmap length (in bits)
2757  * in table->maxlen.
2758  *
2759  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
2760  * large bitmaps may be represented in a compact manner. Writing into
2761  * the file will clear the bitmap then update it with the given input.
2762  *
2763  * Returns 0 on success.
2764  */
2765 int proc_do_large_bitmap(struct ctl_table *table, int write,
2766 			 void __user *buffer, size_t *lenp, loff_t *ppos)
2767 {
2768 	int err = 0;
2769 	bool first = 1;
2770 	size_t left = *lenp;
2771 	unsigned long bitmap_len = table->maxlen;
2772 	unsigned long *bitmap = (unsigned long *) table->data;
2773 	unsigned long *tmp_bitmap = NULL;
2774 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
2775 
2776 	if (!bitmap_len || !left || (*ppos && !write)) {
2777 		*lenp = 0;
2778 		return 0;
2779 	}
2780 
2781 	if (write) {
2782 		unsigned long page = 0;
2783 		char *kbuf;
2784 
2785 		if (left > PAGE_SIZE - 1)
2786 			left = PAGE_SIZE - 1;
2787 
2788 		page = __get_free_page(GFP_TEMPORARY);
2789 		kbuf = (char *) page;
2790 		if (!kbuf)
2791 			return -ENOMEM;
2792 		if (copy_from_user(kbuf, buffer, left)) {
2793 			free_page(page);
2794 			return -EFAULT;
2795                 }
2796 		kbuf[left] = 0;
2797 
2798 		tmp_bitmap = kzalloc(BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long),
2799 				     GFP_KERNEL);
2800 		if (!tmp_bitmap) {
2801 			free_page(page);
2802 			return -ENOMEM;
2803 		}
2804 		proc_skip_char(&kbuf, &left, '\n');
2805 		while (!err && left) {
2806 			unsigned long val_a, val_b;
2807 			bool neg;
2808 
2809 			err = proc_get_long(&kbuf, &left, &val_a, &neg, tr_a,
2810 					     sizeof(tr_a), &c);
2811 			if (err)
2812 				break;
2813 			if (val_a >= bitmap_len || neg) {
2814 				err = -EINVAL;
2815 				break;
2816 			}
2817 
2818 			val_b = val_a;
2819 			if (left) {
2820 				kbuf++;
2821 				left--;
2822 			}
2823 
2824 			if (c == '-') {
2825 				err = proc_get_long(&kbuf, &left, &val_b,
2826 						     &neg, tr_b, sizeof(tr_b),
2827 						     &c);
2828 				if (err)
2829 					break;
2830 				if (val_b >= bitmap_len || neg ||
2831 				    val_a > val_b) {
2832 					err = -EINVAL;
2833 					break;
2834 				}
2835 				if (left) {
2836 					kbuf++;
2837 					left--;
2838 				}
2839 			}
2840 
2841 			while (val_a <= val_b)
2842 				set_bit(val_a++, tmp_bitmap);
2843 
2844 			first = 0;
2845 			proc_skip_char(&kbuf, &left, '\n');
2846 		}
2847 		free_page(page);
2848 	} else {
2849 		unsigned long bit_a, bit_b = 0;
2850 
2851 		while (left) {
2852 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
2853 			if (bit_a >= bitmap_len)
2854 				break;
2855 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
2856 						   bit_a + 1) - 1;
2857 
2858 			if (!first) {
2859 				err = proc_put_char(&buffer, &left, ',');
2860 				if (err)
2861 					break;
2862 			}
2863 			err = proc_put_long(&buffer, &left, bit_a, false);
2864 			if (err)
2865 				break;
2866 			if (bit_a != bit_b) {
2867 				err = proc_put_char(&buffer, &left, '-');
2868 				if (err)
2869 					break;
2870 				err = proc_put_long(&buffer, &left, bit_b, false);
2871 				if (err)
2872 					break;
2873 			}
2874 
2875 			first = 0; bit_b++;
2876 		}
2877 		if (!err)
2878 			err = proc_put_char(&buffer, &left, '\n');
2879 	}
2880 
2881 	if (!err) {
2882 		if (write) {
2883 			if (*ppos)
2884 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
2885 			else
2886 				memcpy(bitmap, tmp_bitmap,
2887 					BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
2888 		}
2889 		kfree(tmp_bitmap);
2890 		*lenp -= left;
2891 		*ppos += *lenp;
2892 		return 0;
2893 	} else {
2894 		kfree(tmp_bitmap);
2895 		return err;
2896 	}
2897 }
2898 
2899 #else /* CONFIG_PROC_FS */
2900 
2901 int proc_dostring(struct ctl_table *table, int write,
2902 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2903 {
2904 	return -ENOSYS;
2905 }
2906 
2907 int proc_dointvec(struct ctl_table *table, int write,
2908 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2909 {
2910 	return -ENOSYS;
2911 }
2912 
2913 int proc_dointvec_minmax(struct ctl_table *table, int write,
2914 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2915 {
2916 	return -ENOSYS;
2917 }
2918 
2919 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2920 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2921 {
2922 	return -ENOSYS;
2923 }
2924 
2925 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2926 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2927 {
2928 	return -ENOSYS;
2929 }
2930 
2931 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2932 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2933 {
2934 	return -ENOSYS;
2935 }
2936 
2937 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2938 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2939 {
2940 	return -ENOSYS;
2941 }
2942 
2943 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2944 				      void __user *buffer,
2945 				      size_t *lenp, loff_t *ppos)
2946 {
2947     return -ENOSYS;
2948 }
2949 
2950 
2951 #endif /* CONFIG_PROC_FS */
2952 
2953 /*
2954  * No sense putting this after each symbol definition, twice,
2955  * exception granted :-)
2956  */
2957 EXPORT_SYMBOL(proc_dointvec);
2958 EXPORT_SYMBOL(proc_dointvec_jiffies);
2959 EXPORT_SYMBOL(proc_dointvec_minmax);
2960 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2961 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2962 EXPORT_SYMBOL(proc_dostring);
2963 EXPORT_SYMBOL(proc_doulongvec_minmax);
2964 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2965 EXPORT_SYMBOL(register_sysctl_table);
2966 EXPORT_SYMBOL(register_sysctl_paths);
2967 EXPORT_SYMBOL(unregister_sysctl_table);
2968