xref: /linux/kernel/sysctl.c (revision 2504075d383fcefd746dac42a0cd1c3bdc006bd1)
1 /*
2  * sysctl.c: General linux system control interface
3  *
4  * Begun 24 March 1995, Stephen Tweedie
5  * Added /proc support, Dec 1995
6  * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
7  * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
8  * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
9  * Dynamic registration fixes, Stephen Tweedie.
10  * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
11  * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
12  *  Horn.
13  * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
14  * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
15  * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
16  *  Wendling.
17  * The list_for_each() macro wasn't appropriate for the sysctl loop.
18  *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
19  */
20 
21 #include <linux/module.h>
22 #include <linux/mm.h>
23 #include <linux/swap.h>
24 #include <linux/slab.h>
25 #include <linux/sysctl.h>
26 #include <linux/signal.h>
27 #include <linux/proc_fs.h>
28 #include <linux/security.h>
29 #include <linux/ctype.h>
30 #include <linux/kmemcheck.h>
31 #include <linux/fs.h>
32 #include <linux/init.h>
33 #include <linux/kernel.h>
34 #include <linux/kobject.h>
35 #include <linux/net.h>
36 #include <linux/sysrq.h>
37 #include <linux/highuid.h>
38 #include <linux/writeback.h>
39 #include <linux/ratelimit.h>
40 #include <linux/compaction.h>
41 #include <linux/hugetlb.h>
42 #include <linux/initrd.h>
43 #include <linux/key.h>
44 #include <linux/times.h>
45 #include <linux/limits.h>
46 #include <linux/dcache.h>
47 #include <linux/dnotify.h>
48 #include <linux/syscalls.h>
49 #include <linux/vmstat.h>
50 #include <linux/nfs_fs.h>
51 #include <linux/acpi.h>
52 #include <linux/reboot.h>
53 #include <linux/ftrace.h>
54 #include <linux/perf_event.h>
55 #include <linux/kprobes.h>
56 #include <linux/pipe_fs_i.h>
57 #include <linux/oom.h>
58 
59 #include <asm/uaccess.h>
60 #include <asm/processor.h>
61 
62 #ifdef CONFIG_X86
63 #include <asm/nmi.h>
64 #include <asm/stacktrace.h>
65 #include <asm/io.h>
66 #endif
67 #ifdef CONFIG_BSD_PROCESS_ACCT
68 #include <linux/acct.h>
69 #endif
70 #ifdef CONFIG_RT_MUTEXES
71 #include <linux/rtmutex.h>
72 #endif
73 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_LOCK_STAT)
74 #include <linux/lockdep.h>
75 #endif
76 #ifdef CONFIG_CHR_DEV_SG
77 #include <scsi/sg.h>
78 #endif
79 
80 #ifdef CONFIG_LOCKUP_DETECTOR
81 #include <linux/nmi.h>
82 #endif
83 
84 
85 #if defined(CONFIG_SYSCTL)
86 
87 /* External variables not in a header file. */
88 extern int sysctl_overcommit_memory;
89 extern int sysctl_overcommit_ratio;
90 extern int max_threads;
91 extern int core_uses_pid;
92 extern int suid_dumpable;
93 extern char core_pattern[];
94 extern unsigned int core_pipe_limit;
95 extern int pid_max;
96 extern int min_free_kbytes;
97 extern int pid_max_min, pid_max_max;
98 extern int sysctl_drop_caches;
99 extern int percpu_pagelist_fraction;
100 extern int compat_log;
101 extern int latencytop_enabled;
102 extern int sysctl_nr_open_min, sysctl_nr_open_max;
103 #ifndef CONFIG_MMU
104 extern int sysctl_nr_trim_pages;
105 #endif
106 #ifdef CONFIG_BLOCK
107 extern int blk_iopoll_enabled;
108 #endif
109 
110 /* Constants used for minimum and  maximum */
111 #ifdef CONFIG_LOCKUP_DETECTOR
112 static int sixty = 60;
113 static int neg_one = -1;
114 #endif
115 
116 static int zero;
117 static int __maybe_unused one = 1;
118 static int __maybe_unused two = 2;
119 static unsigned long one_ul = 1;
120 static int one_hundred = 100;
121 #ifdef CONFIG_PRINTK
122 static int ten_thousand = 10000;
123 #endif
124 
125 /* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
126 static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;
127 
128 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
129 static int maxolduid = 65535;
130 static int minolduid;
131 static int min_percpu_pagelist_fract = 8;
132 
133 static int ngroups_max = NGROUPS_MAX;
134 
135 #ifdef CONFIG_INOTIFY_USER
136 #include <linux/inotify.h>
137 #endif
138 #ifdef CONFIG_SPARC
139 #include <asm/system.h>
140 #endif
141 
142 #ifdef CONFIG_SPARC64
143 extern int sysctl_tsb_ratio;
144 #endif
145 
146 #ifdef __hppa__
147 extern int pwrsw_enabled;
148 extern int unaligned_enabled;
149 #endif
150 
151 #ifdef CONFIG_S390
152 #ifdef CONFIG_MATHEMU
153 extern int sysctl_ieee_emulation_warnings;
154 #endif
155 extern int sysctl_userprocess_debug;
156 extern int spin_retry;
157 #endif
158 
159 #ifdef CONFIG_IA64
160 extern int no_unaligned_warning;
161 extern int unaligned_dump_stack;
162 #endif
163 
164 #ifdef CONFIG_PROC_SYSCTL
165 static int proc_do_cad_pid(struct ctl_table *table, int write,
166 		  void __user *buffer, size_t *lenp, loff_t *ppos);
167 static int proc_taint(struct ctl_table *table, int write,
168 			       void __user *buffer, size_t *lenp, loff_t *ppos);
169 #endif
170 
171 #ifdef CONFIG_MAGIC_SYSRQ
172 static int __sysrq_enabled; /* Note: sysrq code ises it's own private copy */
173 
174 static int sysrq_sysctl_handler(ctl_table *table, int write,
175 				void __user *buffer, size_t *lenp,
176 				loff_t *ppos)
177 {
178 	int error;
179 
180 	error = proc_dointvec(table, write, buffer, lenp, ppos);
181 	if (error)
182 		return error;
183 
184 	if (write)
185 		sysrq_toggle_support(__sysrq_enabled);
186 
187 	return 0;
188 }
189 
190 #endif
191 
192 static struct ctl_table root_table[];
193 static struct ctl_table_root sysctl_table_root;
194 static struct ctl_table_header root_table_header = {
195 	.count = 1,
196 	.ctl_table = root_table,
197 	.ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),
198 	.root = &sysctl_table_root,
199 	.set = &sysctl_table_root.default_set,
200 };
201 static struct ctl_table_root sysctl_table_root = {
202 	.root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
203 	.default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
204 };
205 
206 static struct ctl_table kern_table[];
207 static struct ctl_table vm_table[];
208 static struct ctl_table fs_table[];
209 static struct ctl_table debug_table[];
210 static struct ctl_table dev_table[];
211 extern struct ctl_table random_table[];
212 #ifdef CONFIG_EPOLL
213 extern struct ctl_table epoll_table[];
214 #endif
215 
216 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
217 int sysctl_legacy_va_layout;
218 #endif
219 
220 /* The default sysctl tables: */
221 
222 static struct ctl_table root_table[] = {
223 	{
224 		.procname	= "kernel",
225 		.mode		= 0555,
226 		.child		= kern_table,
227 	},
228 	{
229 		.procname	= "vm",
230 		.mode		= 0555,
231 		.child		= vm_table,
232 	},
233 	{
234 		.procname	= "fs",
235 		.mode		= 0555,
236 		.child		= fs_table,
237 	},
238 	{
239 		.procname	= "debug",
240 		.mode		= 0555,
241 		.child		= debug_table,
242 	},
243 	{
244 		.procname	= "dev",
245 		.mode		= 0555,
246 		.child		= dev_table,
247 	},
248 /*
249  * NOTE: do not add new entries to this table unless you have read
250  * Documentation/sysctl/ctl_unnumbered.txt
251  */
252 	{ }
253 };
254 
255 #ifdef CONFIG_SCHED_DEBUG
256 static int min_sched_granularity_ns = 100000;		/* 100 usecs */
257 static int max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
258 static int min_wakeup_granularity_ns;			/* 0 usecs */
259 static int max_wakeup_granularity_ns = NSEC_PER_SEC;	/* 1 second */
260 static int min_sched_tunable_scaling = SCHED_TUNABLESCALING_NONE;
261 static int max_sched_tunable_scaling = SCHED_TUNABLESCALING_END-1;
262 static int min_sched_shares_ratelimit = 100000; /* 100 usec */
263 static int max_sched_shares_ratelimit = NSEC_PER_SEC; /* 1 second */
264 #endif
265 
266 #ifdef CONFIG_COMPACTION
267 static int min_extfrag_threshold;
268 static int max_extfrag_threshold = 1000;
269 #endif
270 
271 static struct ctl_table kern_table[] = {
272 	{
273 		.procname	= "sched_child_runs_first",
274 		.data		= &sysctl_sched_child_runs_first,
275 		.maxlen		= sizeof(unsigned int),
276 		.mode		= 0644,
277 		.proc_handler	= proc_dointvec,
278 	},
279 #ifdef CONFIG_SCHED_DEBUG
280 	{
281 		.procname	= "sched_min_granularity_ns",
282 		.data		= &sysctl_sched_min_granularity,
283 		.maxlen		= sizeof(unsigned int),
284 		.mode		= 0644,
285 		.proc_handler	= sched_proc_update_handler,
286 		.extra1		= &min_sched_granularity_ns,
287 		.extra2		= &max_sched_granularity_ns,
288 	},
289 	{
290 		.procname	= "sched_latency_ns",
291 		.data		= &sysctl_sched_latency,
292 		.maxlen		= sizeof(unsigned int),
293 		.mode		= 0644,
294 		.proc_handler	= sched_proc_update_handler,
295 		.extra1		= &min_sched_granularity_ns,
296 		.extra2		= &max_sched_granularity_ns,
297 	},
298 	{
299 		.procname	= "sched_wakeup_granularity_ns",
300 		.data		= &sysctl_sched_wakeup_granularity,
301 		.maxlen		= sizeof(unsigned int),
302 		.mode		= 0644,
303 		.proc_handler	= sched_proc_update_handler,
304 		.extra1		= &min_wakeup_granularity_ns,
305 		.extra2		= &max_wakeup_granularity_ns,
306 	},
307 	{
308 		.procname	= "sched_shares_ratelimit",
309 		.data		= &sysctl_sched_shares_ratelimit,
310 		.maxlen		= sizeof(unsigned int),
311 		.mode		= 0644,
312 		.proc_handler	= sched_proc_update_handler,
313 		.extra1		= &min_sched_shares_ratelimit,
314 		.extra2		= &max_sched_shares_ratelimit,
315 	},
316 	{
317 		.procname	= "sched_tunable_scaling",
318 		.data		= &sysctl_sched_tunable_scaling,
319 		.maxlen		= sizeof(enum sched_tunable_scaling),
320 		.mode		= 0644,
321 		.proc_handler	= sched_proc_update_handler,
322 		.extra1		= &min_sched_tunable_scaling,
323 		.extra2		= &max_sched_tunable_scaling,
324 	},
325 	{
326 		.procname	= "sched_shares_thresh",
327 		.data		= &sysctl_sched_shares_thresh,
328 		.maxlen		= sizeof(unsigned int),
329 		.mode		= 0644,
330 		.proc_handler	= proc_dointvec_minmax,
331 		.extra1		= &zero,
332 	},
333 	{
334 		.procname	= "sched_migration_cost",
335 		.data		= &sysctl_sched_migration_cost,
336 		.maxlen		= sizeof(unsigned int),
337 		.mode		= 0644,
338 		.proc_handler	= proc_dointvec,
339 	},
340 	{
341 		.procname	= "sched_nr_migrate",
342 		.data		= &sysctl_sched_nr_migrate,
343 		.maxlen		= sizeof(unsigned int),
344 		.mode		= 0644,
345 		.proc_handler	= proc_dointvec,
346 	},
347 	{
348 		.procname	= "sched_time_avg",
349 		.data		= &sysctl_sched_time_avg,
350 		.maxlen		= sizeof(unsigned int),
351 		.mode		= 0644,
352 		.proc_handler	= proc_dointvec,
353 	},
354 	{
355 		.procname	= "timer_migration",
356 		.data		= &sysctl_timer_migration,
357 		.maxlen		= sizeof(unsigned int),
358 		.mode		= 0644,
359 		.proc_handler	= proc_dointvec_minmax,
360 		.extra1		= &zero,
361 		.extra2		= &one,
362 	},
363 #endif
364 	{
365 		.procname	= "sched_rt_period_us",
366 		.data		= &sysctl_sched_rt_period,
367 		.maxlen		= sizeof(unsigned int),
368 		.mode		= 0644,
369 		.proc_handler	= sched_rt_handler,
370 	},
371 	{
372 		.procname	= "sched_rt_runtime_us",
373 		.data		= &sysctl_sched_rt_runtime,
374 		.maxlen		= sizeof(int),
375 		.mode		= 0644,
376 		.proc_handler	= sched_rt_handler,
377 	},
378 	{
379 		.procname	= "sched_compat_yield",
380 		.data		= &sysctl_sched_compat_yield,
381 		.maxlen		= sizeof(unsigned int),
382 		.mode		= 0644,
383 		.proc_handler	= proc_dointvec,
384 	},
385 #ifdef CONFIG_PROVE_LOCKING
386 	{
387 		.procname	= "prove_locking",
388 		.data		= &prove_locking,
389 		.maxlen		= sizeof(int),
390 		.mode		= 0644,
391 		.proc_handler	= proc_dointvec,
392 	},
393 #endif
394 #ifdef CONFIG_LOCK_STAT
395 	{
396 		.procname	= "lock_stat",
397 		.data		= &lock_stat,
398 		.maxlen		= sizeof(int),
399 		.mode		= 0644,
400 		.proc_handler	= proc_dointvec,
401 	},
402 #endif
403 	{
404 		.procname	= "panic",
405 		.data		= &panic_timeout,
406 		.maxlen		= sizeof(int),
407 		.mode		= 0644,
408 		.proc_handler	= proc_dointvec,
409 	},
410 	{
411 		.procname	= "core_uses_pid",
412 		.data		= &core_uses_pid,
413 		.maxlen		= sizeof(int),
414 		.mode		= 0644,
415 		.proc_handler	= proc_dointvec,
416 	},
417 	{
418 		.procname	= "core_pattern",
419 		.data		= core_pattern,
420 		.maxlen		= CORENAME_MAX_SIZE,
421 		.mode		= 0644,
422 		.proc_handler	= proc_dostring,
423 	},
424 	{
425 		.procname	= "core_pipe_limit",
426 		.data		= &core_pipe_limit,
427 		.maxlen		= sizeof(unsigned int),
428 		.mode		= 0644,
429 		.proc_handler	= proc_dointvec,
430 	},
431 #ifdef CONFIG_PROC_SYSCTL
432 	{
433 		.procname	= "tainted",
434 		.maxlen 	= sizeof(long),
435 		.mode		= 0644,
436 		.proc_handler	= proc_taint,
437 	},
438 #endif
439 #ifdef CONFIG_LATENCYTOP
440 	{
441 		.procname	= "latencytop",
442 		.data		= &latencytop_enabled,
443 		.maxlen		= sizeof(int),
444 		.mode		= 0644,
445 		.proc_handler	= proc_dointvec,
446 	},
447 #endif
448 #ifdef CONFIG_BLK_DEV_INITRD
449 	{
450 		.procname	= "real-root-dev",
451 		.data		= &real_root_dev,
452 		.maxlen		= sizeof(int),
453 		.mode		= 0644,
454 		.proc_handler	= proc_dointvec,
455 	},
456 #endif
457 	{
458 		.procname	= "print-fatal-signals",
459 		.data		= &print_fatal_signals,
460 		.maxlen		= sizeof(int),
461 		.mode		= 0644,
462 		.proc_handler	= proc_dointvec,
463 	},
464 #ifdef CONFIG_SPARC
465 	{
466 		.procname	= "reboot-cmd",
467 		.data		= reboot_command,
468 		.maxlen		= 256,
469 		.mode		= 0644,
470 		.proc_handler	= proc_dostring,
471 	},
472 	{
473 		.procname	= "stop-a",
474 		.data		= &stop_a_enabled,
475 		.maxlen		= sizeof (int),
476 		.mode		= 0644,
477 		.proc_handler	= proc_dointvec,
478 	},
479 	{
480 		.procname	= "scons-poweroff",
481 		.data		= &scons_pwroff,
482 		.maxlen		= sizeof (int),
483 		.mode		= 0644,
484 		.proc_handler	= proc_dointvec,
485 	},
486 #endif
487 #ifdef CONFIG_SPARC64
488 	{
489 		.procname	= "tsb-ratio",
490 		.data		= &sysctl_tsb_ratio,
491 		.maxlen		= sizeof (int),
492 		.mode		= 0644,
493 		.proc_handler	= proc_dointvec,
494 	},
495 #endif
496 #ifdef __hppa__
497 	{
498 		.procname	= "soft-power",
499 		.data		= &pwrsw_enabled,
500 		.maxlen		= sizeof (int),
501 	 	.mode		= 0644,
502 		.proc_handler	= proc_dointvec,
503 	},
504 	{
505 		.procname	= "unaligned-trap",
506 		.data		= &unaligned_enabled,
507 		.maxlen		= sizeof (int),
508 		.mode		= 0644,
509 		.proc_handler	= proc_dointvec,
510 	},
511 #endif
512 	{
513 		.procname	= "ctrl-alt-del",
514 		.data		= &C_A_D,
515 		.maxlen		= sizeof(int),
516 		.mode		= 0644,
517 		.proc_handler	= proc_dointvec,
518 	},
519 #ifdef CONFIG_FUNCTION_TRACER
520 	{
521 		.procname	= "ftrace_enabled",
522 		.data		= &ftrace_enabled,
523 		.maxlen		= sizeof(int),
524 		.mode		= 0644,
525 		.proc_handler	= ftrace_enable_sysctl,
526 	},
527 #endif
528 #ifdef CONFIG_STACK_TRACER
529 	{
530 		.procname	= "stack_tracer_enabled",
531 		.data		= &stack_tracer_enabled,
532 		.maxlen		= sizeof(int),
533 		.mode		= 0644,
534 		.proc_handler	= stack_trace_sysctl,
535 	},
536 #endif
537 #ifdef CONFIG_TRACING
538 	{
539 		.procname	= "ftrace_dump_on_oops",
540 		.data		= &ftrace_dump_on_oops,
541 		.maxlen		= sizeof(int),
542 		.mode		= 0644,
543 		.proc_handler	= proc_dointvec,
544 	},
545 #endif
546 #ifdef CONFIG_MODULES
547 	{
548 		.procname	= "modprobe",
549 		.data		= &modprobe_path,
550 		.maxlen		= KMOD_PATH_LEN,
551 		.mode		= 0644,
552 		.proc_handler	= proc_dostring,
553 	},
554 	{
555 		.procname	= "modules_disabled",
556 		.data		= &modules_disabled,
557 		.maxlen		= sizeof(int),
558 		.mode		= 0644,
559 		/* only handle a transition from default "0" to "1" */
560 		.proc_handler	= proc_dointvec_minmax,
561 		.extra1		= &one,
562 		.extra2		= &one,
563 	},
564 #endif
565 #ifdef CONFIG_HOTPLUG
566 	{
567 		.procname	= "hotplug",
568 		.data		= &uevent_helper,
569 		.maxlen		= UEVENT_HELPER_PATH_LEN,
570 		.mode		= 0644,
571 		.proc_handler	= proc_dostring,
572 	},
573 #endif
574 #ifdef CONFIG_CHR_DEV_SG
575 	{
576 		.procname	= "sg-big-buff",
577 		.data		= &sg_big_buff,
578 		.maxlen		= sizeof (int),
579 		.mode		= 0444,
580 		.proc_handler	= proc_dointvec,
581 	},
582 #endif
583 #ifdef CONFIG_BSD_PROCESS_ACCT
584 	{
585 		.procname	= "acct",
586 		.data		= &acct_parm,
587 		.maxlen		= 3*sizeof(int),
588 		.mode		= 0644,
589 		.proc_handler	= proc_dointvec,
590 	},
591 #endif
592 #ifdef CONFIG_MAGIC_SYSRQ
593 	{
594 		.procname	= "sysrq",
595 		.data		= &__sysrq_enabled,
596 		.maxlen		= sizeof (int),
597 		.mode		= 0644,
598 		.proc_handler	= sysrq_sysctl_handler,
599 	},
600 #endif
601 #ifdef CONFIG_PROC_SYSCTL
602 	{
603 		.procname	= "cad_pid",
604 		.data		= NULL,
605 		.maxlen		= sizeof (int),
606 		.mode		= 0600,
607 		.proc_handler	= proc_do_cad_pid,
608 	},
609 #endif
610 	{
611 		.procname	= "threads-max",
612 		.data		= &max_threads,
613 		.maxlen		= sizeof(int),
614 		.mode		= 0644,
615 		.proc_handler	= proc_dointvec,
616 	},
617 	{
618 		.procname	= "random",
619 		.mode		= 0555,
620 		.child		= random_table,
621 	},
622 	{
623 		.procname	= "overflowuid",
624 		.data		= &overflowuid,
625 		.maxlen		= sizeof(int),
626 		.mode		= 0644,
627 		.proc_handler	= proc_dointvec_minmax,
628 		.extra1		= &minolduid,
629 		.extra2		= &maxolduid,
630 	},
631 	{
632 		.procname	= "overflowgid",
633 		.data		= &overflowgid,
634 		.maxlen		= sizeof(int),
635 		.mode		= 0644,
636 		.proc_handler	= proc_dointvec_minmax,
637 		.extra1		= &minolduid,
638 		.extra2		= &maxolduid,
639 	},
640 #ifdef CONFIG_S390
641 #ifdef CONFIG_MATHEMU
642 	{
643 		.procname	= "ieee_emulation_warnings",
644 		.data		= &sysctl_ieee_emulation_warnings,
645 		.maxlen		= sizeof(int),
646 		.mode		= 0644,
647 		.proc_handler	= proc_dointvec,
648 	},
649 #endif
650 	{
651 		.procname	= "userprocess_debug",
652 		.data		= &show_unhandled_signals,
653 		.maxlen		= sizeof(int),
654 		.mode		= 0644,
655 		.proc_handler	= proc_dointvec,
656 	},
657 #endif
658 	{
659 		.procname	= "pid_max",
660 		.data		= &pid_max,
661 		.maxlen		= sizeof (int),
662 		.mode		= 0644,
663 		.proc_handler	= proc_dointvec_minmax,
664 		.extra1		= &pid_max_min,
665 		.extra2		= &pid_max_max,
666 	},
667 	{
668 		.procname	= "panic_on_oops",
669 		.data		= &panic_on_oops,
670 		.maxlen		= sizeof(int),
671 		.mode		= 0644,
672 		.proc_handler	= proc_dointvec,
673 	},
674 #if defined CONFIG_PRINTK
675 	{
676 		.procname	= "printk",
677 		.data		= &console_loglevel,
678 		.maxlen		= 4*sizeof(int),
679 		.mode		= 0644,
680 		.proc_handler	= proc_dointvec,
681 	},
682 	{
683 		.procname	= "printk_ratelimit",
684 		.data		= &printk_ratelimit_state.interval,
685 		.maxlen		= sizeof(int),
686 		.mode		= 0644,
687 		.proc_handler	= proc_dointvec_jiffies,
688 	},
689 	{
690 		.procname	= "printk_ratelimit_burst",
691 		.data		= &printk_ratelimit_state.burst,
692 		.maxlen		= sizeof(int),
693 		.mode		= 0644,
694 		.proc_handler	= proc_dointvec,
695 	},
696 	{
697 		.procname	= "printk_delay",
698 		.data		= &printk_delay_msec,
699 		.maxlen		= sizeof(int),
700 		.mode		= 0644,
701 		.proc_handler	= proc_dointvec_minmax,
702 		.extra1		= &zero,
703 		.extra2		= &ten_thousand,
704 	},
705 #endif
706 	{
707 		.procname	= "ngroups_max",
708 		.data		= &ngroups_max,
709 		.maxlen		= sizeof (int),
710 		.mode		= 0444,
711 		.proc_handler	= proc_dointvec,
712 	},
713 #if defined(CONFIG_LOCKUP_DETECTOR)
714 	{
715 		.procname       = "watchdog",
716 		.data           = &watchdog_enabled,
717 		.maxlen         = sizeof (int),
718 		.mode           = 0644,
719 		.proc_handler   = proc_dowatchdog_enabled,
720 	},
721 	{
722 		.procname	= "watchdog_thresh",
723 		.data		= &softlockup_thresh,
724 		.maxlen		= sizeof(int),
725 		.mode		= 0644,
726 		.proc_handler	= proc_dowatchdog_thresh,
727 		.extra1		= &neg_one,
728 		.extra2		= &sixty,
729 	},
730 	{
731 		.procname	= "softlockup_panic",
732 		.data		= &softlockup_panic,
733 		.maxlen		= sizeof(int),
734 		.mode		= 0644,
735 		.proc_handler	= proc_dointvec_minmax,
736 		.extra1		= &zero,
737 		.extra2		= &one,
738 	},
739 #endif
740 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86) && !defined(CONFIG_LOCKUP_DETECTOR)
741 	{
742 		.procname       = "unknown_nmi_panic",
743 		.data           = &unknown_nmi_panic,
744 		.maxlen         = sizeof (int),
745 		.mode           = 0644,
746 		.proc_handler   = proc_dointvec,
747 	},
748 	{
749 		.procname       = "nmi_watchdog",
750 		.data           = &nmi_watchdog_enabled,
751 		.maxlen         = sizeof (int),
752 		.mode           = 0644,
753 		.proc_handler   = proc_nmi_enabled,
754 	},
755 #endif
756 #if defined(CONFIG_X86)
757 	{
758 		.procname	= "panic_on_unrecovered_nmi",
759 		.data		= &panic_on_unrecovered_nmi,
760 		.maxlen		= sizeof(int),
761 		.mode		= 0644,
762 		.proc_handler	= proc_dointvec,
763 	},
764 	{
765 		.procname	= "panic_on_io_nmi",
766 		.data		= &panic_on_io_nmi,
767 		.maxlen		= sizeof(int),
768 		.mode		= 0644,
769 		.proc_handler	= proc_dointvec,
770 	},
771 	{
772 		.procname	= "bootloader_type",
773 		.data		= &bootloader_type,
774 		.maxlen		= sizeof (int),
775 		.mode		= 0444,
776 		.proc_handler	= proc_dointvec,
777 	},
778 	{
779 		.procname	= "bootloader_version",
780 		.data		= &bootloader_version,
781 		.maxlen		= sizeof (int),
782 		.mode		= 0444,
783 		.proc_handler	= proc_dointvec,
784 	},
785 	{
786 		.procname	= "kstack_depth_to_print",
787 		.data		= &kstack_depth_to_print,
788 		.maxlen		= sizeof(int),
789 		.mode		= 0644,
790 		.proc_handler	= proc_dointvec,
791 	},
792 	{
793 		.procname	= "io_delay_type",
794 		.data		= &io_delay_type,
795 		.maxlen		= sizeof(int),
796 		.mode		= 0644,
797 		.proc_handler	= proc_dointvec,
798 	},
799 #endif
800 #if defined(CONFIG_MMU)
801 	{
802 		.procname	= "randomize_va_space",
803 		.data		= &randomize_va_space,
804 		.maxlen		= sizeof(int),
805 		.mode		= 0644,
806 		.proc_handler	= proc_dointvec,
807 	},
808 #endif
809 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
810 	{
811 		.procname	= "spin_retry",
812 		.data		= &spin_retry,
813 		.maxlen		= sizeof (int),
814 		.mode		= 0644,
815 		.proc_handler	= proc_dointvec,
816 	},
817 #endif
818 #if	defined(CONFIG_ACPI_SLEEP) && defined(CONFIG_X86)
819 	{
820 		.procname	= "acpi_video_flags",
821 		.data		= &acpi_realmode_flags,
822 		.maxlen		= sizeof (unsigned long),
823 		.mode		= 0644,
824 		.proc_handler	= proc_doulongvec_minmax,
825 	},
826 #endif
827 #ifdef CONFIG_IA64
828 	{
829 		.procname	= "ignore-unaligned-usertrap",
830 		.data		= &no_unaligned_warning,
831 		.maxlen		= sizeof (int),
832 	 	.mode		= 0644,
833 		.proc_handler	= proc_dointvec,
834 	},
835 	{
836 		.procname	= "unaligned-dump-stack",
837 		.data		= &unaligned_dump_stack,
838 		.maxlen		= sizeof (int),
839 		.mode		= 0644,
840 		.proc_handler	= proc_dointvec,
841 	},
842 #endif
843 #ifdef CONFIG_DETECT_HUNG_TASK
844 	{
845 		.procname	= "hung_task_panic",
846 		.data		= &sysctl_hung_task_panic,
847 		.maxlen		= sizeof(int),
848 		.mode		= 0644,
849 		.proc_handler	= proc_dointvec_minmax,
850 		.extra1		= &zero,
851 		.extra2		= &one,
852 	},
853 	{
854 		.procname	= "hung_task_check_count",
855 		.data		= &sysctl_hung_task_check_count,
856 		.maxlen		= sizeof(unsigned long),
857 		.mode		= 0644,
858 		.proc_handler	= proc_doulongvec_minmax,
859 	},
860 	{
861 		.procname	= "hung_task_timeout_secs",
862 		.data		= &sysctl_hung_task_timeout_secs,
863 		.maxlen		= sizeof(unsigned long),
864 		.mode		= 0644,
865 		.proc_handler	= proc_dohung_task_timeout_secs,
866 	},
867 	{
868 		.procname	= "hung_task_warnings",
869 		.data		= &sysctl_hung_task_warnings,
870 		.maxlen		= sizeof(unsigned long),
871 		.mode		= 0644,
872 		.proc_handler	= proc_doulongvec_minmax,
873 	},
874 #endif
875 #ifdef CONFIG_COMPAT
876 	{
877 		.procname	= "compat-log",
878 		.data		= &compat_log,
879 		.maxlen		= sizeof (int),
880 	 	.mode		= 0644,
881 		.proc_handler	= proc_dointvec,
882 	},
883 #endif
884 #ifdef CONFIG_RT_MUTEXES
885 	{
886 		.procname	= "max_lock_depth",
887 		.data		= &max_lock_depth,
888 		.maxlen		= sizeof(int),
889 		.mode		= 0644,
890 		.proc_handler	= proc_dointvec,
891 	},
892 #endif
893 	{
894 		.procname	= "poweroff_cmd",
895 		.data		= &poweroff_cmd,
896 		.maxlen		= POWEROFF_CMD_PATH_LEN,
897 		.mode		= 0644,
898 		.proc_handler	= proc_dostring,
899 	},
900 #ifdef CONFIG_KEYS
901 	{
902 		.procname	= "keys",
903 		.mode		= 0555,
904 		.child		= key_sysctls,
905 	},
906 #endif
907 #ifdef CONFIG_RCU_TORTURE_TEST
908 	{
909 		.procname       = "rcutorture_runnable",
910 		.data           = &rcutorture_runnable,
911 		.maxlen         = sizeof(int),
912 		.mode           = 0644,
913 		.proc_handler	= proc_dointvec,
914 	},
915 #endif
916 #ifdef CONFIG_PERF_EVENTS
917 	{
918 		.procname	= "perf_event_paranoid",
919 		.data		= &sysctl_perf_event_paranoid,
920 		.maxlen		= sizeof(sysctl_perf_event_paranoid),
921 		.mode		= 0644,
922 		.proc_handler	= proc_dointvec,
923 	},
924 	{
925 		.procname	= "perf_event_mlock_kb",
926 		.data		= &sysctl_perf_event_mlock,
927 		.maxlen		= sizeof(sysctl_perf_event_mlock),
928 		.mode		= 0644,
929 		.proc_handler	= proc_dointvec,
930 	},
931 	{
932 		.procname	= "perf_event_max_sample_rate",
933 		.data		= &sysctl_perf_event_sample_rate,
934 		.maxlen		= sizeof(sysctl_perf_event_sample_rate),
935 		.mode		= 0644,
936 		.proc_handler	= proc_dointvec,
937 	},
938 #endif
939 #ifdef CONFIG_KMEMCHECK
940 	{
941 		.procname	= "kmemcheck",
942 		.data		= &kmemcheck_enabled,
943 		.maxlen		= sizeof(int),
944 		.mode		= 0644,
945 		.proc_handler	= proc_dointvec,
946 	},
947 #endif
948 #ifdef CONFIG_BLOCK
949 	{
950 		.procname	= "blk_iopoll",
951 		.data		= &blk_iopoll_enabled,
952 		.maxlen		= sizeof(int),
953 		.mode		= 0644,
954 		.proc_handler	= proc_dointvec,
955 	},
956 #endif
957 /*
958  * NOTE: do not add new entries to this table unless you have read
959  * Documentation/sysctl/ctl_unnumbered.txt
960  */
961 	{ }
962 };
963 
964 static struct ctl_table vm_table[] = {
965 	{
966 		.procname	= "overcommit_memory",
967 		.data		= &sysctl_overcommit_memory,
968 		.maxlen		= sizeof(sysctl_overcommit_memory),
969 		.mode		= 0644,
970 		.proc_handler	= proc_dointvec,
971 	},
972 	{
973 		.procname	= "panic_on_oom",
974 		.data		= &sysctl_panic_on_oom,
975 		.maxlen		= sizeof(sysctl_panic_on_oom),
976 		.mode		= 0644,
977 		.proc_handler	= proc_dointvec,
978 	},
979 	{
980 		.procname	= "oom_kill_allocating_task",
981 		.data		= &sysctl_oom_kill_allocating_task,
982 		.maxlen		= sizeof(sysctl_oom_kill_allocating_task),
983 		.mode		= 0644,
984 		.proc_handler	= proc_dointvec,
985 	},
986 	{
987 		.procname	= "oom_dump_tasks",
988 		.data		= &sysctl_oom_dump_tasks,
989 		.maxlen		= sizeof(sysctl_oom_dump_tasks),
990 		.mode		= 0644,
991 		.proc_handler	= proc_dointvec,
992 	},
993 	{
994 		.procname	= "overcommit_ratio",
995 		.data		= &sysctl_overcommit_ratio,
996 		.maxlen		= sizeof(sysctl_overcommit_ratio),
997 		.mode		= 0644,
998 		.proc_handler	= proc_dointvec,
999 	},
1000 	{
1001 		.procname	= "page-cluster",
1002 		.data		= &page_cluster,
1003 		.maxlen		= sizeof(int),
1004 		.mode		= 0644,
1005 		.proc_handler	= proc_dointvec,
1006 	},
1007 	{
1008 		.procname	= "dirty_background_ratio",
1009 		.data		= &dirty_background_ratio,
1010 		.maxlen		= sizeof(dirty_background_ratio),
1011 		.mode		= 0644,
1012 		.proc_handler	= dirty_background_ratio_handler,
1013 		.extra1		= &zero,
1014 		.extra2		= &one_hundred,
1015 	},
1016 	{
1017 		.procname	= "dirty_background_bytes",
1018 		.data		= &dirty_background_bytes,
1019 		.maxlen		= sizeof(dirty_background_bytes),
1020 		.mode		= 0644,
1021 		.proc_handler	= dirty_background_bytes_handler,
1022 		.extra1		= &one_ul,
1023 	},
1024 	{
1025 		.procname	= "dirty_ratio",
1026 		.data		= &vm_dirty_ratio,
1027 		.maxlen		= sizeof(vm_dirty_ratio),
1028 		.mode		= 0644,
1029 		.proc_handler	= dirty_ratio_handler,
1030 		.extra1		= &zero,
1031 		.extra2		= &one_hundred,
1032 	},
1033 	{
1034 		.procname	= "dirty_bytes",
1035 		.data		= &vm_dirty_bytes,
1036 		.maxlen		= sizeof(vm_dirty_bytes),
1037 		.mode		= 0644,
1038 		.proc_handler	= dirty_bytes_handler,
1039 		.extra1		= &dirty_bytes_min,
1040 	},
1041 	{
1042 		.procname	= "dirty_writeback_centisecs",
1043 		.data		= &dirty_writeback_interval,
1044 		.maxlen		= sizeof(dirty_writeback_interval),
1045 		.mode		= 0644,
1046 		.proc_handler	= dirty_writeback_centisecs_handler,
1047 	},
1048 	{
1049 		.procname	= "dirty_expire_centisecs",
1050 		.data		= &dirty_expire_interval,
1051 		.maxlen		= sizeof(dirty_expire_interval),
1052 		.mode		= 0644,
1053 		.proc_handler	= proc_dointvec,
1054 	},
1055 	{
1056 		.procname	= "nr_pdflush_threads",
1057 		.data		= &nr_pdflush_threads,
1058 		.maxlen		= sizeof nr_pdflush_threads,
1059 		.mode		= 0444 /* read-only*/,
1060 		.proc_handler	= proc_dointvec,
1061 	},
1062 	{
1063 		.procname	= "swappiness",
1064 		.data		= &vm_swappiness,
1065 		.maxlen		= sizeof(vm_swappiness),
1066 		.mode		= 0644,
1067 		.proc_handler	= proc_dointvec_minmax,
1068 		.extra1		= &zero,
1069 		.extra2		= &one_hundred,
1070 	},
1071 #ifdef CONFIG_HUGETLB_PAGE
1072 	{
1073 		.procname	= "nr_hugepages",
1074 		.data		= NULL,
1075 		.maxlen		= sizeof(unsigned long),
1076 		.mode		= 0644,
1077 		.proc_handler	= hugetlb_sysctl_handler,
1078 		.extra1		= (void *)&hugetlb_zero,
1079 		.extra2		= (void *)&hugetlb_infinity,
1080 	},
1081 #ifdef CONFIG_NUMA
1082 	{
1083 		.procname       = "nr_hugepages_mempolicy",
1084 		.data           = NULL,
1085 		.maxlen         = sizeof(unsigned long),
1086 		.mode           = 0644,
1087 		.proc_handler   = &hugetlb_mempolicy_sysctl_handler,
1088 		.extra1		= (void *)&hugetlb_zero,
1089 		.extra2		= (void *)&hugetlb_infinity,
1090 	},
1091 #endif
1092 	 {
1093 		.procname	= "hugetlb_shm_group",
1094 		.data		= &sysctl_hugetlb_shm_group,
1095 		.maxlen		= sizeof(gid_t),
1096 		.mode		= 0644,
1097 		.proc_handler	= proc_dointvec,
1098 	 },
1099 	 {
1100 		.procname	= "hugepages_treat_as_movable",
1101 		.data		= &hugepages_treat_as_movable,
1102 		.maxlen		= sizeof(int),
1103 		.mode		= 0644,
1104 		.proc_handler	= hugetlb_treat_movable_handler,
1105 	},
1106 	{
1107 		.procname	= "nr_overcommit_hugepages",
1108 		.data		= NULL,
1109 		.maxlen		= sizeof(unsigned long),
1110 		.mode		= 0644,
1111 		.proc_handler	= hugetlb_overcommit_handler,
1112 		.extra1		= (void *)&hugetlb_zero,
1113 		.extra2		= (void *)&hugetlb_infinity,
1114 	},
1115 #endif
1116 	{
1117 		.procname	= "lowmem_reserve_ratio",
1118 		.data		= &sysctl_lowmem_reserve_ratio,
1119 		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
1120 		.mode		= 0644,
1121 		.proc_handler	= lowmem_reserve_ratio_sysctl_handler,
1122 	},
1123 	{
1124 		.procname	= "drop_caches",
1125 		.data		= &sysctl_drop_caches,
1126 		.maxlen		= sizeof(int),
1127 		.mode		= 0644,
1128 		.proc_handler	= drop_caches_sysctl_handler,
1129 	},
1130 #ifdef CONFIG_COMPACTION
1131 	{
1132 		.procname	= "compact_memory",
1133 		.data		= &sysctl_compact_memory,
1134 		.maxlen		= sizeof(int),
1135 		.mode		= 0200,
1136 		.proc_handler	= sysctl_compaction_handler,
1137 	},
1138 	{
1139 		.procname	= "extfrag_threshold",
1140 		.data		= &sysctl_extfrag_threshold,
1141 		.maxlen		= sizeof(int),
1142 		.mode		= 0644,
1143 		.proc_handler	= sysctl_extfrag_handler,
1144 		.extra1		= &min_extfrag_threshold,
1145 		.extra2		= &max_extfrag_threshold,
1146 	},
1147 
1148 #endif /* CONFIG_COMPACTION */
1149 	{
1150 		.procname	= "min_free_kbytes",
1151 		.data		= &min_free_kbytes,
1152 		.maxlen		= sizeof(min_free_kbytes),
1153 		.mode		= 0644,
1154 		.proc_handler	= min_free_kbytes_sysctl_handler,
1155 		.extra1		= &zero,
1156 	},
1157 	{
1158 		.procname	= "percpu_pagelist_fraction",
1159 		.data		= &percpu_pagelist_fraction,
1160 		.maxlen		= sizeof(percpu_pagelist_fraction),
1161 		.mode		= 0644,
1162 		.proc_handler	= percpu_pagelist_fraction_sysctl_handler,
1163 		.extra1		= &min_percpu_pagelist_fract,
1164 	},
1165 #ifdef CONFIG_MMU
1166 	{
1167 		.procname	= "max_map_count",
1168 		.data		= &sysctl_max_map_count,
1169 		.maxlen		= sizeof(sysctl_max_map_count),
1170 		.mode		= 0644,
1171 		.proc_handler	= proc_dointvec_minmax,
1172 		.extra1		= &zero,
1173 	},
1174 #else
1175 	{
1176 		.procname	= "nr_trim_pages",
1177 		.data		= &sysctl_nr_trim_pages,
1178 		.maxlen		= sizeof(sysctl_nr_trim_pages),
1179 		.mode		= 0644,
1180 		.proc_handler	= proc_dointvec_minmax,
1181 		.extra1		= &zero,
1182 	},
1183 #endif
1184 	{
1185 		.procname	= "laptop_mode",
1186 		.data		= &laptop_mode,
1187 		.maxlen		= sizeof(laptop_mode),
1188 		.mode		= 0644,
1189 		.proc_handler	= proc_dointvec_jiffies,
1190 	},
1191 	{
1192 		.procname	= "block_dump",
1193 		.data		= &block_dump,
1194 		.maxlen		= sizeof(block_dump),
1195 		.mode		= 0644,
1196 		.proc_handler	= proc_dointvec,
1197 		.extra1		= &zero,
1198 	},
1199 	{
1200 		.procname	= "vfs_cache_pressure",
1201 		.data		= &sysctl_vfs_cache_pressure,
1202 		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
1203 		.mode		= 0644,
1204 		.proc_handler	= proc_dointvec,
1205 		.extra1		= &zero,
1206 	},
1207 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
1208 	{
1209 		.procname	= "legacy_va_layout",
1210 		.data		= &sysctl_legacy_va_layout,
1211 		.maxlen		= sizeof(sysctl_legacy_va_layout),
1212 		.mode		= 0644,
1213 		.proc_handler	= proc_dointvec,
1214 		.extra1		= &zero,
1215 	},
1216 #endif
1217 #ifdef CONFIG_NUMA
1218 	{
1219 		.procname	= "zone_reclaim_mode",
1220 		.data		= &zone_reclaim_mode,
1221 		.maxlen		= sizeof(zone_reclaim_mode),
1222 		.mode		= 0644,
1223 		.proc_handler	= proc_dointvec,
1224 		.extra1		= &zero,
1225 	},
1226 	{
1227 		.procname	= "min_unmapped_ratio",
1228 		.data		= &sysctl_min_unmapped_ratio,
1229 		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
1230 		.mode		= 0644,
1231 		.proc_handler	= sysctl_min_unmapped_ratio_sysctl_handler,
1232 		.extra1		= &zero,
1233 		.extra2		= &one_hundred,
1234 	},
1235 	{
1236 		.procname	= "min_slab_ratio",
1237 		.data		= &sysctl_min_slab_ratio,
1238 		.maxlen		= sizeof(sysctl_min_slab_ratio),
1239 		.mode		= 0644,
1240 		.proc_handler	= sysctl_min_slab_ratio_sysctl_handler,
1241 		.extra1		= &zero,
1242 		.extra2		= &one_hundred,
1243 	},
1244 #endif
1245 #ifdef CONFIG_SMP
1246 	{
1247 		.procname	= "stat_interval",
1248 		.data		= &sysctl_stat_interval,
1249 		.maxlen		= sizeof(sysctl_stat_interval),
1250 		.mode		= 0644,
1251 		.proc_handler	= proc_dointvec_jiffies,
1252 	},
1253 #endif
1254 #ifdef CONFIG_MMU
1255 	{
1256 		.procname	= "mmap_min_addr",
1257 		.data		= &dac_mmap_min_addr,
1258 		.maxlen		= sizeof(unsigned long),
1259 		.mode		= 0644,
1260 		.proc_handler	= mmap_min_addr_handler,
1261 	},
1262 #endif
1263 #ifdef CONFIG_NUMA
1264 	{
1265 		.procname	= "numa_zonelist_order",
1266 		.data		= &numa_zonelist_order,
1267 		.maxlen		= NUMA_ZONELIST_ORDER_LEN,
1268 		.mode		= 0644,
1269 		.proc_handler	= numa_zonelist_order_handler,
1270 	},
1271 #endif
1272 #if (defined(CONFIG_X86_32) && !defined(CONFIG_UML))|| \
1273    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
1274 	{
1275 		.procname	= "vdso_enabled",
1276 		.data		= &vdso_enabled,
1277 		.maxlen		= sizeof(vdso_enabled),
1278 		.mode		= 0644,
1279 		.proc_handler	= proc_dointvec,
1280 		.extra1		= &zero,
1281 	},
1282 #endif
1283 #ifdef CONFIG_HIGHMEM
1284 	{
1285 		.procname	= "highmem_is_dirtyable",
1286 		.data		= &vm_highmem_is_dirtyable,
1287 		.maxlen		= sizeof(vm_highmem_is_dirtyable),
1288 		.mode		= 0644,
1289 		.proc_handler	= proc_dointvec_minmax,
1290 		.extra1		= &zero,
1291 		.extra2		= &one,
1292 	},
1293 #endif
1294 	{
1295 		.procname	= "scan_unevictable_pages",
1296 		.data		= &scan_unevictable_pages,
1297 		.maxlen		= sizeof(scan_unevictable_pages),
1298 		.mode		= 0644,
1299 		.proc_handler	= scan_unevictable_handler,
1300 	},
1301 #ifdef CONFIG_MEMORY_FAILURE
1302 	{
1303 		.procname	= "memory_failure_early_kill",
1304 		.data		= &sysctl_memory_failure_early_kill,
1305 		.maxlen		= sizeof(sysctl_memory_failure_early_kill),
1306 		.mode		= 0644,
1307 		.proc_handler	= proc_dointvec_minmax,
1308 		.extra1		= &zero,
1309 		.extra2		= &one,
1310 	},
1311 	{
1312 		.procname	= "memory_failure_recovery",
1313 		.data		= &sysctl_memory_failure_recovery,
1314 		.maxlen		= sizeof(sysctl_memory_failure_recovery),
1315 		.mode		= 0644,
1316 		.proc_handler	= proc_dointvec_minmax,
1317 		.extra1		= &zero,
1318 		.extra2		= &one,
1319 	},
1320 #endif
1321 
1322 /*
1323  * NOTE: do not add new entries to this table unless you have read
1324  * Documentation/sysctl/ctl_unnumbered.txt
1325  */
1326 	{ }
1327 };
1328 
1329 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1330 static struct ctl_table binfmt_misc_table[] = {
1331 	{ }
1332 };
1333 #endif
1334 
1335 static struct ctl_table fs_table[] = {
1336 	{
1337 		.procname	= "inode-nr",
1338 		.data		= &inodes_stat,
1339 		.maxlen		= 2*sizeof(int),
1340 		.mode		= 0444,
1341 		.proc_handler	= proc_nr_inodes,
1342 	},
1343 	{
1344 		.procname	= "inode-state",
1345 		.data		= &inodes_stat,
1346 		.maxlen		= 7*sizeof(int),
1347 		.mode		= 0444,
1348 		.proc_handler	= proc_nr_inodes,
1349 	},
1350 	{
1351 		.procname	= "file-nr",
1352 		.data		= &files_stat,
1353 		.maxlen		= sizeof(files_stat),
1354 		.mode		= 0444,
1355 		.proc_handler	= proc_nr_files,
1356 	},
1357 	{
1358 		.procname	= "file-max",
1359 		.data		= &files_stat.max_files,
1360 		.maxlen		= sizeof(files_stat.max_files),
1361 		.mode		= 0644,
1362 		.proc_handler	= proc_doulongvec_minmax,
1363 	},
1364 	{
1365 		.procname	= "nr_open",
1366 		.data		= &sysctl_nr_open,
1367 		.maxlen		= sizeof(int),
1368 		.mode		= 0644,
1369 		.proc_handler	= proc_dointvec_minmax,
1370 		.extra1		= &sysctl_nr_open_min,
1371 		.extra2		= &sysctl_nr_open_max,
1372 	},
1373 	{
1374 		.procname	= "dentry-state",
1375 		.data		= &dentry_stat,
1376 		.maxlen		= 6*sizeof(int),
1377 		.mode		= 0444,
1378 		.proc_handler	= proc_nr_dentry,
1379 	},
1380 	{
1381 		.procname	= "overflowuid",
1382 		.data		= &fs_overflowuid,
1383 		.maxlen		= sizeof(int),
1384 		.mode		= 0644,
1385 		.proc_handler	= proc_dointvec_minmax,
1386 		.extra1		= &minolduid,
1387 		.extra2		= &maxolduid,
1388 	},
1389 	{
1390 		.procname	= "overflowgid",
1391 		.data		= &fs_overflowgid,
1392 		.maxlen		= sizeof(int),
1393 		.mode		= 0644,
1394 		.proc_handler	= proc_dointvec_minmax,
1395 		.extra1		= &minolduid,
1396 		.extra2		= &maxolduid,
1397 	},
1398 #ifdef CONFIG_FILE_LOCKING
1399 	{
1400 		.procname	= "leases-enable",
1401 		.data		= &leases_enable,
1402 		.maxlen		= sizeof(int),
1403 		.mode		= 0644,
1404 		.proc_handler	= proc_dointvec,
1405 	},
1406 #endif
1407 #ifdef CONFIG_DNOTIFY
1408 	{
1409 		.procname	= "dir-notify-enable",
1410 		.data		= &dir_notify_enable,
1411 		.maxlen		= sizeof(int),
1412 		.mode		= 0644,
1413 		.proc_handler	= proc_dointvec,
1414 	},
1415 #endif
1416 #ifdef CONFIG_MMU
1417 #ifdef CONFIG_FILE_LOCKING
1418 	{
1419 		.procname	= "lease-break-time",
1420 		.data		= &lease_break_time,
1421 		.maxlen		= sizeof(int),
1422 		.mode		= 0644,
1423 		.proc_handler	= proc_dointvec,
1424 	},
1425 #endif
1426 #ifdef CONFIG_AIO
1427 	{
1428 		.procname	= "aio-nr",
1429 		.data		= &aio_nr,
1430 		.maxlen		= sizeof(aio_nr),
1431 		.mode		= 0444,
1432 		.proc_handler	= proc_doulongvec_minmax,
1433 	},
1434 	{
1435 		.procname	= "aio-max-nr",
1436 		.data		= &aio_max_nr,
1437 		.maxlen		= sizeof(aio_max_nr),
1438 		.mode		= 0644,
1439 		.proc_handler	= proc_doulongvec_minmax,
1440 	},
1441 #endif /* CONFIG_AIO */
1442 #ifdef CONFIG_INOTIFY_USER
1443 	{
1444 		.procname	= "inotify",
1445 		.mode		= 0555,
1446 		.child		= inotify_table,
1447 	},
1448 #endif
1449 #ifdef CONFIG_EPOLL
1450 	{
1451 		.procname	= "epoll",
1452 		.mode		= 0555,
1453 		.child		= epoll_table,
1454 	},
1455 #endif
1456 #endif
1457 	{
1458 		.procname	= "suid_dumpable",
1459 		.data		= &suid_dumpable,
1460 		.maxlen		= sizeof(int),
1461 		.mode		= 0644,
1462 		.proc_handler	= proc_dointvec_minmax,
1463 		.extra1		= &zero,
1464 		.extra2		= &two,
1465 	},
1466 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1467 	{
1468 		.procname	= "binfmt_misc",
1469 		.mode		= 0555,
1470 		.child		= binfmt_misc_table,
1471 	},
1472 #endif
1473 	{
1474 		.procname	= "pipe-max-size",
1475 		.data		= &pipe_max_size,
1476 		.maxlen		= sizeof(int),
1477 		.mode		= 0644,
1478 		.proc_handler	= &pipe_proc_fn,
1479 		.extra1		= &pipe_min_size,
1480 	},
1481 /*
1482  * NOTE: do not add new entries to this table unless you have read
1483  * Documentation/sysctl/ctl_unnumbered.txt
1484  */
1485 	{ }
1486 };
1487 
1488 static struct ctl_table debug_table[] = {
1489 #if defined(CONFIG_X86) || defined(CONFIG_PPC) || defined(CONFIG_SPARC) || \
1490     defined(CONFIG_S390)
1491 	{
1492 		.procname	= "exception-trace",
1493 		.data		= &show_unhandled_signals,
1494 		.maxlen		= sizeof(int),
1495 		.mode		= 0644,
1496 		.proc_handler	= proc_dointvec
1497 	},
1498 #endif
1499 #if defined(CONFIG_OPTPROBES)
1500 	{
1501 		.procname	= "kprobes-optimization",
1502 		.data		= &sysctl_kprobes_optimization,
1503 		.maxlen		= sizeof(int),
1504 		.mode		= 0644,
1505 		.proc_handler	= proc_kprobes_optimization_handler,
1506 		.extra1		= &zero,
1507 		.extra2		= &one,
1508 	},
1509 #endif
1510 	{ }
1511 };
1512 
1513 static struct ctl_table dev_table[] = {
1514 	{ }
1515 };
1516 
1517 static DEFINE_SPINLOCK(sysctl_lock);
1518 
1519 /* called under sysctl_lock */
1520 static int use_table(struct ctl_table_header *p)
1521 {
1522 	if (unlikely(p->unregistering))
1523 		return 0;
1524 	p->used++;
1525 	return 1;
1526 }
1527 
1528 /* called under sysctl_lock */
1529 static void unuse_table(struct ctl_table_header *p)
1530 {
1531 	if (!--p->used)
1532 		if (unlikely(p->unregistering))
1533 			complete(p->unregistering);
1534 }
1535 
1536 /* called under sysctl_lock, will reacquire if has to wait */
1537 static void start_unregistering(struct ctl_table_header *p)
1538 {
1539 	/*
1540 	 * if p->used is 0, nobody will ever touch that entry again;
1541 	 * we'll eliminate all paths to it before dropping sysctl_lock
1542 	 */
1543 	if (unlikely(p->used)) {
1544 		struct completion wait;
1545 		init_completion(&wait);
1546 		p->unregistering = &wait;
1547 		spin_unlock(&sysctl_lock);
1548 		wait_for_completion(&wait);
1549 		spin_lock(&sysctl_lock);
1550 	} else {
1551 		/* anything non-NULL; we'll never dereference it */
1552 		p->unregistering = ERR_PTR(-EINVAL);
1553 	}
1554 	/*
1555 	 * do not remove from the list until nobody holds it; walking the
1556 	 * list in do_sysctl() relies on that.
1557 	 */
1558 	list_del_init(&p->ctl_entry);
1559 }
1560 
1561 void sysctl_head_get(struct ctl_table_header *head)
1562 {
1563 	spin_lock(&sysctl_lock);
1564 	head->count++;
1565 	spin_unlock(&sysctl_lock);
1566 }
1567 
1568 void sysctl_head_put(struct ctl_table_header *head)
1569 {
1570 	spin_lock(&sysctl_lock);
1571 	if (!--head->count)
1572 		kfree(head);
1573 	spin_unlock(&sysctl_lock);
1574 }
1575 
1576 struct ctl_table_header *sysctl_head_grab(struct ctl_table_header *head)
1577 {
1578 	if (!head)
1579 		BUG();
1580 	spin_lock(&sysctl_lock);
1581 	if (!use_table(head))
1582 		head = ERR_PTR(-ENOENT);
1583 	spin_unlock(&sysctl_lock);
1584 	return head;
1585 }
1586 
1587 void sysctl_head_finish(struct ctl_table_header *head)
1588 {
1589 	if (!head)
1590 		return;
1591 	spin_lock(&sysctl_lock);
1592 	unuse_table(head);
1593 	spin_unlock(&sysctl_lock);
1594 }
1595 
1596 static struct ctl_table_set *
1597 lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
1598 {
1599 	struct ctl_table_set *set = &root->default_set;
1600 	if (root->lookup)
1601 		set = root->lookup(root, namespaces);
1602 	return set;
1603 }
1604 
1605 static struct list_head *
1606 lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
1607 {
1608 	struct ctl_table_set *set = lookup_header_set(root, namespaces);
1609 	return &set->list;
1610 }
1611 
1612 struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
1613 					    struct ctl_table_header *prev)
1614 {
1615 	struct ctl_table_root *root;
1616 	struct list_head *header_list;
1617 	struct ctl_table_header *head;
1618 	struct list_head *tmp;
1619 
1620 	spin_lock(&sysctl_lock);
1621 	if (prev) {
1622 		head = prev;
1623 		tmp = &prev->ctl_entry;
1624 		unuse_table(prev);
1625 		goto next;
1626 	}
1627 	tmp = &root_table_header.ctl_entry;
1628 	for (;;) {
1629 		head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1630 
1631 		if (!use_table(head))
1632 			goto next;
1633 		spin_unlock(&sysctl_lock);
1634 		return head;
1635 	next:
1636 		root = head->root;
1637 		tmp = tmp->next;
1638 		header_list = lookup_header_list(root, namespaces);
1639 		if (tmp != header_list)
1640 			continue;
1641 
1642 		do {
1643 			root = list_entry(root->root_list.next,
1644 					struct ctl_table_root, root_list);
1645 			if (root == &sysctl_table_root)
1646 				goto out;
1647 			header_list = lookup_header_list(root, namespaces);
1648 		} while (list_empty(header_list));
1649 		tmp = header_list->next;
1650 	}
1651 out:
1652 	spin_unlock(&sysctl_lock);
1653 	return NULL;
1654 }
1655 
1656 struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1657 {
1658 	return __sysctl_head_next(current->nsproxy, prev);
1659 }
1660 
1661 void register_sysctl_root(struct ctl_table_root *root)
1662 {
1663 	spin_lock(&sysctl_lock);
1664 	list_add_tail(&root->root_list, &sysctl_table_root.root_list);
1665 	spin_unlock(&sysctl_lock);
1666 }
1667 
1668 /*
1669  * sysctl_perm does NOT grant the superuser all rights automatically, because
1670  * some sysctl variables are readonly even to root.
1671  */
1672 
1673 static int test_perm(int mode, int op)
1674 {
1675 	if (!current_euid())
1676 		mode >>= 6;
1677 	else if (in_egroup_p(0))
1678 		mode >>= 3;
1679 	if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
1680 		return 0;
1681 	return -EACCES;
1682 }
1683 
1684 int sysctl_perm(struct ctl_table_root *root, struct ctl_table *table, int op)
1685 {
1686 	int error;
1687 	int mode;
1688 
1689 	error = security_sysctl(table, op & (MAY_READ | MAY_WRITE | MAY_EXEC));
1690 	if (error)
1691 		return error;
1692 
1693 	if (root->permissions)
1694 		mode = root->permissions(root, current->nsproxy, table);
1695 	else
1696 		mode = table->mode;
1697 
1698 	return test_perm(mode, op);
1699 }
1700 
1701 static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1702 {
1703 	for (; table->procname; table++) {
1704 		table->parent = parent;
1705 		if (table->child)
1706 			sysctl_set_parent(table, table->child);
1707 	}
1708 }
1709 
1710 static __init int sysctl_init(void)
1711 {
1712 	sysctl_set_parent(NULL, root_table);
1713 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1714 	sysctl_check_table(current->nsproxy, root_table);
1715 #endif
1716 	return 0;
1717 }
1718 
1719 core_initcall(sysctl_init);
1720 
1721 static struct ctl_table *is_branch_in(struct ctl_table *branch,
1722 				      struct ctl_table *table)
1723 {
1724 	struct ctl_table *p;
1725 	const char *s = branch->procname;
1726 
1727 	/* branch should have named subdirectory as its first element */
1728 	if (!s || !branch->child)
1729 		return NULL;
1730 
1731 	/* ... and nothing else */
1732 	if (branch[1].procname)
1733 		return NULL;
1734 
1735 	/* table should contain subdirectory with the same name */
1736 	for (p = table; p->procname; p++) {
1737 		if (!p->child)
1738 			continue;
1739 		if (p->procname && strcmp(p->procname, s) == 0)
1740 			return p;
1741 	}
1742 	return NULL;
1743 }
1744 
1745 /* see if attaching q to p would be an improvement */
1746 static void try_attach(struct ctl_table_header *p, struct ctl_table_header *q)
1747 {
1748 	struct ctl_table *to = p->ctl_table, *by = q->ctl_table;
1749 	struct ctl_table *next;
1750 	int is_better = 0;
1751 	int not_in_parent = !p->attached_by;
1752 
1753 	while ((next = is_branch_in(by, to)) != NULL) {
1754 		if (by == q->attached_by)
1755 			is_better = 1;
1756 		if (to == p->attached_by)
1757 			not_in_parent = 1;
1758 		by = by->child;
1759 		to = next->child;
1760 	}
1761 
1762 	if (is_better && not_in_parent) {
1763 		q->attached_by = by;
1764 		q->attached_to = to;
1765 		q->parent = p;
1766 	}
1767 }
1768 
1769 /**
1770  * __register_sysctl_paths - register a sysctl hierarchy
1771  * @root: List of sysctl headers to register on
1772  * @namespaces: Data to compute which lists of sysctl entries are visible
1773  * @path: The path to the directory the sysctl table is in.
1774  * @table: the top-level table structure
1775  *
1776  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1777  * array. A completely 0 filled entry terminates the table.
1778  *
1779  * The members of the &struct ctl_table structure are used as follows:
1780  *
1781  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1782  *            enter a sysctl file
1783  *
1784  * data - a pointer to data for use by proc_handler
1785  *
1786  * maxlen - the maximum size in bytes of the data
1787  *
1788  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1789  *
1790  * child - a pointer to the child sysctl table if this entry is a directory, or
1791  *         %NULL.
1792  *
1793  * proc_handler - the text handler routine (described below)
1794  *
1795  * de - for internal use by the sysctl routines
1796  *
1797  * extra1, extra2 - extra pointers usable by the proc handler routines
1798  *
1799  * Leaf nodes in the sysctl tree will be represented by a single file
1800  * under /proc; non-leaf nodes will be represented by directories.
1801  *
1802  * sysctl(2) can automatically manage read and write requests through
1803  * the sysctl table.  The data and maxlen fields of the ctl_table
1804  * struct enable minimal validation of the values being written to be
1805  * performed, and the mode field allows minimal authentication.
1806  *
1807  * There must be a proc_handler routine for any terminal nodes
1808  * mirrored under /proc/sys (non-terminals are handled by a built-in
1809  * directory handler).  Several default handlers are available to
1810  * cover common cases -
1811  *
1812  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1813  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1814  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1815  *
1816  * It is the handler's job to read the input buffer from user memory
1817  * and process it. The handler should return 0 on success.
1818  *
1819  * This routine returns %NULL on a failure to register, and a pointer
1820  * to the table header on success.
1821  */
1822 struct ctl_table_header *__register_sysctl_paths(
1823 	struct ctl_table_root *root,
1824 	struct nsproxy *namespaces,
1825 	const struct ctl_path *path, struct ctl_table *table)
1826 {
1827 	struct ctl_table_header *header;
1828 	struct ctl_table *new, **prevp;
1829 	unsigned int n, npath;
1830 	struct ctl_table_set *set;
1831 
1832 	/* Count the path components */
1833 	for (npath = 0; path[npath].procname; ++npath)
1834 		;
1835 
1836 	/*
1837 	 * For each path component, allocate a 2-element ctl_table array.
1838 	 * The first array element will be filled with the sysctl entry
1839 	 * for this, the second will be the sentinel (procname == 0).
1840 	 *
1841 	 * We allocate everything in one go so that we don't have to
1842 	 * worry about freeing additional memory in unregister_sysctl_table.
1843 	 */
1844 	header = kzalloc(sizeof(struct ctl_table_header) +
1845 			 (2 * npath * sizeof(struct ctl_table)), GFP_KERNEL);
1846 	if (!header)
1847 		return NULL;
1848 
1849 	new = (struct ctl_table *) (header + 1);
1850 
1851 	/* Now connect the dots */
1852 	prevp = &header->ctl_table;
1853 	for (n = 0; n < npath; ++n, ++path) {
1854 		/* Copy the procname */
1855 		new->procname = path->procname;
1856 		new->mode     = 0555;
1857 
1858 		*prevp = new;
1859 		prevp = &new->child;
1860 
1861 		new += 2;
1862 	}
1863 	*prevp = table;
1864 	header->ctl_table_arg = table;
1865 
1866 	INIT_LIST_HEAD(&header->ctl_entry);
1867 	header->used = 0;
1868 	header->unregistering = NULL;
1869 	header->root = root;
1870 	sysctl_set_parent(NULL, header->ctl_table);
1871 	header->count = 1;
1872 #ifdef CONFIG_SYSCTL_SYSCALL_CHECK
1873 	if (sysctl_check_table(namespaces, header->ctl_table)) {
1874 		kfree(header);
1875 		return NULL;
1876 	}
1877 #endif
1878 	spin_lock(&sysctl_lock);
1879 	header->set = lookup_header_set(root, namespaces);
1880 	header->attached_by = header->ctl_table;
1881 	header->attached_to = root_table;
1882 	header->parent = &root_table_header;
1883 	for (set = header->set; set; set = set->parent) {
1884 		struct ctl_table_header *p;
1885 		list_for_each_entry(p, &set->list, ctl_entry) {
1886 			if (p->unregistering)
1887 				continue;
1888 			try_attach(p, header);
1889 		}
1890 	}
1891 	header->parent->count++;
1892 	list_add_tail(&header->ctl_entry, &header->set->list);
1893 	spin_unlock(&sysctl_lock);
1894 
1895 	return header;
1896 }
1897 
1898 /**
1899  * register_sysctl_table_path - register a sysctl table hierarchy
1900  * @path: The path to the directory the sysctl table is in.
1901  * @table: the top-level table structure
1902  *
1903  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1904  * array. A completely 0 filled entry terminates the table.
1905  *
1906  * See __register_sysctl_paths for more details.
1907  */
1908 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1909 						struct ctl_table *table)
1910 {
1911 	return __register_sysctl_paths(&sysctl_table_root, current->nsproxy,
1912 					path, table);
1913 }
1914 
1915 /**
1916  * register_sysctl_table - register a sysctl table hierarchy
1917  * @table: the top-level table structure
1918  *
1919  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1920  * array. A completely 0 filled entry terminates the table.
1921  *
1922  * See register_sysctl_paths for more details.
1923  */
1924 struct ctl_table_header *register_sysctl_table(struct ctl_table *table)
1925 {
1926 	static const struct ctl_path null_path[] = { {} };
1927 
1928 	return register_sysctl_paths(null_path, table);
1929 }
1930 
1931 /**
1932  * unregister_sysctl_table - unregister a sysctl table hierarchy
1933  * @header: the header returned from register_sysctl_table
1934  *
1935  * Unregisters the sysctl table and all children. proc entries may not
1936  * actually be removed until they are no longer used by anyone.
1937  */
1938 void unregister_sysctl_table(struct ctl_table_header * header)
1939 {
1940 	might_sleep();
1941 
1942 	if (header == NULL)
1943 		return;
1944 
1945 	spin_lock(&sysctl_lock);
1946 	start_unregistering(header);
1947 	if (!--header->parent->count) {
1948 		WARN_ON(1);
1949 		kfree(header->parent);
1950 	}
1951 	if (!--header->count)
1952 		kfree(header);
1953 	spin_unlock(&sysctl_lock);
1954 }
1955 
1956 int sysctl_is_seen(struct ctl_table_header *p)
1957 {
1958 	struct ctl_table_set *set = p->set;
1959 	int res;
1960 	spin_lock(&sysctl_lock);
1961 	if (p->unregistering)
1962 		res = 0;
1963 	else if (!set->is_seen)
1964 		res = 1;
1965 	else
1966 		res = set->is_seen(set);
1967 	spin_unlock(&sysctl_lock);
1968 	return res;
1969 }
1970 
1971 void setup_sysctl_set(struct ctl_table_set *p,
1972 	struct ctl_table_set *parent,
1973 	int (*is_seen)(struct ctl_table_set *))
1974 {
1975 	INIT_LIST_HEAD(&p->list);
1976 	p->parent = parent ? parent : &sysctl_table_root.default_set;
1977 	p->is_seen = is_seen;
1978 }
1979 
1980 #else /* !CONFIG_SYSCTL */
1981 struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
1982 {
1983 	return NULL;
1984 }
1985 
1986 struct ctl_table_header *register_sysctl_paths(const struct ctl_path *path,
1987 						    struct ctl_table *table)
1988 {
1989 	return NULL;
1990 }
1991 
1992 void unregister_sysctl_table(struct ctl_table_header * table)
1993 {
1994 }
1995 
1996 void setup_sysctl_set(struct ctl_table_set *p,
1997 	struct ctl_table_set *parent,
1998 	int (*is_seen)(struct ctl_table_set *))
1999 {
2000 }
2001 
2002 void sysctl_head_put(struct ctl_table_header *head)
2003 {
2004 }
2005 
2006 #endif /* CONFIG_SYSCTL */
2007 
2008 /*
2009  * /proc/sys support
2010  */
2011 
2012 #ifdef CONFIG_PROC_SYSCTL
2013 
2014 static int _proc_do_string(void* data, int maxlen, int write,
2015 			   void __user *buffer,
2016 			   size_t *lenp, loff_t *ppos)
2017 {
2018 	size_t len;
2019 	char __user *p;
2020 	char c;
2021 
2022 	if (!data || !maxlen || !*lenp) {
2023 		*lenp = 0;
2024 		return 0;
2025 	}
2026 
2027 	if (write) {
2028 		len = 0;
2029 		p = buffer;
2030 		while (len < *lenp) {
2031 			if (get_user(c, p++))
2032 				return -EFAULT;
2033 			if (c == 0 || c == '\n')
2034 				break;
2035 			len++;
2036 		}
2037 		if (len >= maxlen)
2038 			len = maxlen-1;
2039 		if(copy_from_user(data, buffer, len))
2040 			return -EFAULT;
2041 		((char *) data)[len] = 0;
2042 		*ppos += *lenp;
2043 	} else {
2044 		len = strlen(data);
2045 		if (len > maxlen)
2046 			len = maxlen;
2047 
2048 		if (*ppos > len) {
2049 			*lenp = 0;
2050 			return 0;
2051 		}
2052 
2053 		data += *ppos;
2054 		len  -= *ppos;
2055 
2056 		if (len > *lenp)
2057 			len = *lenp;
2058 		if (len)
2059 			if(copy_to_user(buffer, data, len))
2060 				return -EFAULT;
2061 		if (len < *lenp) {
2062 			if(put_user('\n', ((char __user *) buffer) + len))
2063 				return -EFAULT;
2064 			len++;
2065 		}
2066 		*lenp = len;
2067 		*ppos += len;
2068 	}
2069 	return 0;
2070 }
2071 
2072 /**
2073  * proc_dostring - read a string sysctl
2074  * @table: the sysctl table
2075  * @write: %TRUE if this is a write to the sysctl file
2076  * @buffer: the user buffer
2077  * @lenp: the size of the user buffer
2078  * @ppos: file position
2079  *
2080  * Reads/writes a string from/to the user buffer. If the kernel
2081  * buffer provided is not large enough to hold the string, the
2082  * string is truncated. The copied string is %NULL-terminated.
2083  * If the string is being read by the user process, it is copied
2084  * and a newline '\n' is added. It is truncated if the buffer is
2085  * not large enough.
2086  *
2087  * Returns 0 on success.
2088  */
2089 int proc_dostring(struct ctl_table *table, int write,
2090 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2091 {
2092 	return _proc_do_string(table->data, table->maxlen, write,
2093 			       buffer, lenp, ppos);
2094 }
2095 
2096 static size_t proc_skip_spaces(char **buf)
2097 {
2098 	size_t ret;
2099 	char *tmp = skip_spaces(*buf);
2100 	ret = tmp - *buf;
2101 	*buf = tmp;
2102 	return ret;
2103 }
2104 
2105 static void proc_skip_char(char **buf, size_t *size, const char v)
2106 {
2107 	while (*size) {
2108 		if (**buf != v)
2109 			break;
2110 		(*size)--;
2111 		(*buf)++;
2112 	}
2113 }
2114 
2115 #define TMPBUFLEN 22
2116 /**
2117  * proc_get_long - reads an ASCII formatted integer from a user buffer
2118  *
2119  * @buf: a kernel buffer
2120  * @size: size of the kernel buffer
2121  * @val: this is where the number will be stored
2122  * @neg: set to %TRUE if number is negative
2123  * @perm_tr: a vector which contains the allowed trailers
2124  * @perm_tr_len: size of the perm_tr vector
2125  * @tr: pointer to store the trailer character
2126  *
2127  * In case of success %0 is returned and @buf and @size are updated with
2128  * the amount of bytes read. If @tr is non-NULL and a trailing
2129  * character exists (size is non-zero after returning from this
2130  * function), @tr is updated with the trailing character.
2131  */
2132 static int proc_get_long(char **buf, size_t *size,
2133 			  unsigned long *val, bool *neg,
2134 			  const char *perm_tr, unsigned perm_tr_len, char *tr)
2135 {
2136 	int len;
2137 	char *p, tmp[TMPBUFLEN];
2138 
2139 	if (!*size)
2140 		return -EINVAL;
2141 
2142 	len = *size;
2143 	if (len > TMPBUFLEN - 1)
2144 		len = TMPBUFLEN - 1;
2145 
2146 	memcpy(tmp, *buf, len);
2147 
2148 	tmp[len] = 0;
2149 	p = tmp;
2150 	if (*p == '-' && *size > 1) {
2151 		*neg = true;
2152 		p++;
2153 	} else
2154 		*neg = false;
2155 	if (!isdigit(*p))
2156 		return -EINVAL;
2157 
2158 	*val = simple_strtoul(p, &p, 0);
2159 
2160 	len = p - tmp;
2161 
2162 	/* We don't know if the next char is whitespace thus we may accept
2163 	 * invalid integers (e.g. 1234...a) or two integers instead of one
2164 	 * (e.g. 123...1). So lets not allow such large numbers. */
2165 	if (len == TMPBUFLEN - 1)
2166 		return -EINVAL;
2167 
2168 	if (len < *size && perm_tr_len && !memchr(perm_tr, *p, perm_tr_len))
2169 		return -EINVAL;
2170 
2171 	if (tr && (len < *size))
2172 		*tr = *p;
2173 
2174 	*buf += len;
2175 	*size -= len;
2176 
2177 	return 0;
2178 }
2179 
2180 /**
2181  * proc_put_long - converts an integer to a decimal ASCII formatted string
2182  *
2183  * @buf: the user buffer
2184  * @size: the size of the user buffer
2185  * @val: the integer to be converted
2186  * @neg: sign of the number, %TRUE for negative
2187  *
2188  * In case of success %0 is returned and @buf and @size are updated with
2189  * the amount of bytes written.
2190  */
2191 static int proc_put_long(void __user **buf, size_t *size, unsigned long val,
2192 			  bool neg)
2193 {
2194 	int len;
2195 	char tmp[TMPBUFLEN], *p = tmp;
2196 
2197 	sprintf(p, "%s%lu", neg ? "-" : "", val);
2198 	len = strlen(tmp);
2199 	if (len > *size)
2200 		len = *size;
2201 	if (copy_to_user(*buf, tmp, len))
2202 		return -EFAULT;
2203 	*size -= len;
2204 	*buf += len;
2205 	return 0;
2206 }
2207 #undef TMPBUFLEN
2208 
2209 static int proc_put_char(void __user **buf, size_t *size, char c)
2210 {
2211 	if (*size) {
2212 		char __user **buffer = (char __user **)buf;
2213 		if (put_user(c, *buffer))
2214 			return -EFAULT;
2215 		(*size)--, (*buffer)++;
2216 		*buf = *buffer;
2217 	}
2218 	return 0;
2219 }
2220 
2221 static int do_proc_dointvec_conv(bool *negp, unsigned long *lvalp,
2222 				 int *valp,
2223 				 int write, void *data)
2224 {
2225 	if (write) {
2226 		*valp = *negp ? -*lvalp : *lvalp;
2227 	} else {
2228 		int val = *valp;
2229 		if (val < 0) {
2230 			*negp = true;
2231 			*lvalp = (unsigned long)-val;
2232 		} else {
2233 			*negp = false;
2234 			*lvalp = (unsigned long)val;
2235 		}
2236 	}
2237 	return 0;
2238 }
2239 
2240 static const char proc_wspace_sep[] = { ' ', '\t', '\n' };
2241 
2242 static int __do_proc_dointvec(void *tbl_data, struct ctl_table *table,
2243 		  int write, void __user *buffer,
2244 		  size_t *lenp, loff_t *ppos,
2245 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2246 			      int write, void *data),
2247 		  void *data)
2248 {
2249 	int *i, vleft, first = 1, err = 0;
2250 	unsigned long page = 0;
2251 	size_t left;
2252 	char *kbuf;
2253 
2254 	if (!tbl_data || !table->maxlen || !*lenp || (*ppos && !write)) {
2255 		*lenp = 0;
2256 		return 0;
2257 	}
2258 
2259 	i = (int *) tbl_data;
2260 	vleft = table->maxlen / sizeof(*i);
2261 	left = *lenp;
2262 
2263 	if (!conv)
2264 		conv = do_proc_dointvec_conv;
2265 
2266 	if (write) {
2267 		if (left > PAGE_SIZE - 1)
2268 			left = PAGE_SIZE - 1;
2269 		page = __get_free_page(GFP_TEMPORARY);
2270 		kbuf = (char *) page;
2271 		if (!kbuf)
2272 			return -ENOMEM;
2273 		if (copy_from_user(kbuf, buffer, left)) {
2274 			err = -EFAULT;
2275 			goto free;
2276 		}
2277 		kbuf[left] = 0;
2278 	}
2279 
2280 	for (; left && vleft--; i++, first=0) {
2281 		unsigned long lval;
2282 		bool neg;
2283 
2284 		if (write) {
2285 			left -= proc_skip_spaces(&kbuf);
2286 
2287 			if (!left)
2288 				break;
2289 			err = proc_get_long(&kbuf, &left, &lval, &neg,
2290 					     proc_wspace_sep,
2291 					     sizeof(proc_wspace_sep), NULL);
2292 			if (err)
2293 				break;
2294 			if (conv(&neg, &lval, i, 1, data)) {
2295 				err = -EINVAL;
2296 				break;
2297 			}
2298 		} else {
2299 			if (conv(&neg, &lval, i, 0, data)) {
2300 				err = -EINVAL;
2301 				break;
2302 			}
2303 			if (!first)
2304 				err = proc_put_char(&buffer, &left, '\t');
2305 			if (err)
2306 				break;
2307 			err = proc_put_long(&buffer, &left, lval, neg);
2308 			if (err)
2309 				break;
2310 		}
2311 	}
2312 
2313 	if (!write && !first && left && !err)
2314 		err = proc_put_char(&buffer, &left, '\n');
2315 	if (write && !err && left)
2316 		left -= proc_skip_spaces(&kbuf);
2317 free:
2318 	if (write) {
2319 		free_page(page);
2320 		if (first)
2321 			return err ? : -EINVAL;
2322 	}
2323 	*lenp -= left;
2324 	*ppos += *lenp;
2325 	return err;
2326 }
2327 
2328 static int do_proc_dointvec(struct ctl_table *table, int write,
2329 		  void __user *buffer, size_t *lenp, loff_t *ppos,
2330 		  int (*conv)(bool *negp, unsigned long *lvalp, int *valp,
2331 			      int write, void *data),
2332 		  void *data)
2333 {
2334 	return __do_proc_dointvec(table->data, table, write,
2335 			buffer, lenp, ppos, conv, data);
2336 }
2337 
2338 /**
2339  * proc_dointvec - read a vector of integers
2340  * @table: the sysctl table
2341  * @write: %TRUE if this is a write to the sysctl file
2342  * @buffer: the user buffer
2343  * @lenp: the size of the user buffer
2344  * @ppos: file position
2345  *
2346  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2347  * values from/to the user buffer, treated as an ASCII string.
2348  *
2349  * Returns 0 on success.
2350  */
2351 int proc_dointvec(struct ctl_table *table, int write,
2352 		     void __user *buffer, size_t *lenp, loff_t *ppos)
2353 {
2354     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2355 		    	    NULL,NULL);
2356 }
2357 
2358 /*
2359  * Taint values can only be increased
2360  * This means we can safely use a temporary.
2361  */
2362 static int proc_taint(struct ctl_table *table, int write,
2363 			       void __user *buffer, size_t *lenp, loff_t *ppos)
2364 {
2365 	struct ctl_table t;
2366 	unsigned long tmptaint = get_taint();
2367 	int err;
2368 
2369 	if (write && !capable(CAP_SYS_ADMIN))
2370 		return -EPERM;
2371 
2372 	t = *table;
2373 	t.data = &tmptaint;
2374 	err = proc_doulongvec_minmax(&t, write, buffer, lenp, ppos);
2375 	if (err < 0)
2376 		return err;
2377 
2378 	if (write) {
2379 		/*
2380 		 * Poor man's atomic or. Not worth adding a primitive
2381 		 * to everyone's atomic.h for this
2382 		 */
2383 		int i;
2384 		for (i = 0; i < BITS_PER_LONG && tmptaint >> i; i++) {
2385 			if ((tmptaint >> i) & 1)
2386 				add_taint(i);
2387 		}
2388 	}
2389 
2390 	return err;
2391 }
2392 
2393 struct do_proc_dointvec_minmax_conv_param {
2394 	int *min;
2395 	int *max;
2396 };
2397 
2398 static int do_proc_dointvec_minmax_conv(bool *negp, unsigned long *lvalp,
2399 					int *valp,
2400 					int write, void *data)
2401 {
2402 	struct do_proc_dointvec_minmax_conv_param *param = data;
2403 	if (write) {
2404 		int val = *negp ? -*lvalp : *lvalp;
2405 		if ((param->min && *param->min > val) ||
2406 		    (param->max && *param->max < val))
2407 			return -EINVAL;
2408 		*valp = val;
2409 	} else {
2410 		int val = *valp;
2411 		if (val < 0) {
2412 			*negp = true;
2413 			*lvalp = (unsigned long)-val;
2414 		} else {
2415 			*negp = false;
2416 			*lvalp = (unsigned long)val;
2417 		}
2418 	}
2419 	return 0;
2420 }
2421 
2422 /**
2423  * proc_dointvec_minmax - read a vector of integers with min/max values
2424  * @table: the sysctl table
2425  * @write: %TRUE if this is a write to the sysctl file
2426  * @buffer: the user buffer
2427  * @lenp: the size of the user buffer
2428  * @ppos: file position
2429  *
2430  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2431  * values from/to the user buffer, treated as an ASCII string.
2432  *
2433  * This routine will ensure the values are within the range specified by
2434  * table->extra1 (min) and table->extra2 (max).
2435  *
2436  * Returns 0 on success.
2437  */
2438 int proc_dointvec_minmax(struct ctl_table *table, int write,
2439 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2440 {
2441 	struct do_proc_dointvec_minmax_conv_param param = {
2442 		.min = (int *) table->extra1,
2443 		.max = (int *) table->extra2,
2444 	};
2445 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2446 				do_proc_dointvec_minmax_conv, &param);
2447 }
2448 
2449 static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write,
2450 				     void __user *buffer,
2451 				     size_t *lenp, loff_t *ppos,
2452 				     unsigned long convmul,
2453 				     unsigned long convdiv)
2454 {
2455 	unsigned long *i, *min, *max;
2456 	int vleft, first = 1, err = 0;
2457 	unsigned long page = 0;
2458 	size_t left;
2459 	char *kbuf;
2460 
2461 	if (!data || !table->maxlen || !*lenp || (*ppos && !write)) {
2462 		*lenp = 0;
2463 		return 0;
2464 	}
2465 
2466 	i = (unsigned long *) data;
2467 	min = (unsigned long *) table->extra1;
2468 	max = (unsigned long *) table->extra2;
2469 	vleft = table->maxlen / sizeof(unsigned long);
2470 	left = *lenp;
2471 
2472 	if (write) {
2473 		if (left > PAGE_SIZE - 1)
2474 			left = PAGE_SIZE - 1;
2475 		page = __get_free_page(GFP_TEMPORARY);
2476 		kbuf = (char *) page;
2477 		if (!kbuf)
2478 			return -ENOMEM;
2479 		if (copy_from_user(kbuf, buffer, left)) {
2480 			err = -EFAULT;
2481 			goto free;
2482 		}
2483 		kbuf[left] = 0;
2484 	}
2485 
2486 	for (; left && vleft--; i++, first = 0) {
2487 		unsigned long val;
2488 
2489 		if (write) {
2490 			bool neg;
2491 
2492 			left -= proc_skip_spaces(&kbuf);
2493 
2494 			err = proc_get_long(&kbuf, &left, &val, &neg,
2495 					     proc_wspace_sep,
2496 					     sizeof(proc_wspace_sep), NULL);
2497 			if (err)
2498 				break;
2499 			if (neg)
2500 				continue;
2501 			if ((min && val < *min) || (max && val > *max))
2502 				continue;
2503 			*i = val;
2504 		} else {
2505 			val = convdiv * (*i) / convmul;
2506 			if (!first)
2507 				err = proc_put_char(&buffer, &left, '\t');
2508 			err = proc_put_long(&buffer, &left, val, false);
2509 			if (err)
2510 				break;
2511 		}
2512 	}
2513 
2514 	if (!write && !first && left && !err)
2515 		err = proc_put_char(&buffer, &left, '\n');
2516 	if (write && !err)
2517 		left -= proc_skip_spaces(&kbuf);
2518 free:
2519 	if (write) {
2520 		free_page(page);
2521 		if (first)
2522 			return err ? : -EINVAL;
2523 	}
2524 	*lenp -= left;
2525 	*ppos += *lenp;
2526 	return err;
2527 }
2528 
2529 static int do_proc_doulongvec_minmax(struct ctl_table *table, int write,
2530 				     void __user *buffer,
2531 				     size_t *lenp, loff_t *ppos,
2532 				     unsigned long convmul,
2533 				     unsigned long convdiv)
2534 {
2535 	return __do_proc_doulongvec_minmax(table->data, table, write,
2536 			buffer, lenp, ppos, convmul, convdiv);
2537 }
2538 
2539 /**
2540  * proc_doulongvec_minmax - read a vector of long integers with min/max values
2541  * @table: the sysctl table
2542  * @write: %TRUE if this is a write to the sysctl file
2543  * @buffer: the user buffer
2544  * @lenp: the size of the user buffer
2545  * @ppos: file position
2546  *
2547  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2548  * values from/to the user buffer, treated as an ASCII string.
2549  *
2550  * This routine will ensure the values are within the range specified by
2551  * table->extra1 (min) and table->extra2 (max).
2552  *
2553  * Returns 0 on success.
2554  */
2555 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2556 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2557 {
2558     return do_proc_doulongvec_minmax(table, write, buffer, lenp, ppos, 1l, 1l);
2559 }
2560 
2561 /**
2562  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2563  * @table: the sysctl table
2564  * @write: %TRUE if this is a write to the sysctl file
2565  * @buffer: the user buffer
2566  * @lenp: the size of the user buffer
2567  * @ppos: file position
2568  *
2569  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2570  * values from/to the user buffer, treated as an ASCII string. The values
2571  * are treated as milliseconds, and converted to jiffies when they are stored.
2572  *
2573  * This routine will ensure the values are within the range specified by
2574  * table->extra1 (min) and table->extra2 (max).
2575  *
2576  * Returns 0 on success.
2577  */
2578 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2579 				      void __user *buffer,
2580 				      size_t *lenp, loff_t *ppos)
2581 {
2582     return do_proc_doulongvec_minmax(table, write, buffer,
2583 				     lenp, ppos, HZ, 1000l);
2584 }
2585 
2586 
2587 static int do_proc_dointvec_jiffies_conv(bool *negp, unsigned long *lvalp,
2588 					 int *valp,
2589 					 int write, void *data)
2590 {
2591 	if (write) {
2592 		if (*lvalp > LONG_MAX / HZ)
2593 			return 1;
2594 		*valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2595 	} else {
2596 		int val = *valp;
2597 		unsigned long lval;
2598 		if (val < 0) {
2599 			*negp = true;
2600 			lval = (unsigned long)-val;
2601 		} else {
2602 			*negp = false;
2603 			lval = (unsigned long)val;
2604 		}
2605 		*lvalp = lval / HZ;
2606 	}
2607 	return 0;
2608 }
2609 
2610 static int do_proc_dointvec_userhz_jiffies_conv(bool *negp, unsigned long *lvalp,
2611 						int *valp,
2612 						int write, void *data)
2613 {
2614 	if (write) {
2615 		if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2616 			return 1;
2617 		*valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2618 	} else {
2619 		int val = *valp;
2620 		unsigned long lval;
2621 		if (val < 0) {
2622 			*negp = true;
2623 			lval = (unsigned long)-val;
2624 		} else {
2625 			*negp = false;
2626 			lval = (unsigned long)val;
2627 		}
2628 		*lvalp = jiffies_to_clock_t(lval);
2629 	}
2630 	return 0;
2631 }
2632 
2633 static int do_proc_dointvec_ms_jiffies_conv(bool *negp, unsigned long *lvalp,
2634 					    int *valp,
2635 					    int write, void *data)
2636 {
2637 	if (write) {
2638 		*valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2639 	} else {
2640 		int val = *valp;
2641 		unsigned long lval;
2642 		if (val < 0) {
2643 			*negp = true;
2644 			lval = (unsigned long)-val;
2645 		} else {
2646 			*negp = false;
2647 			lval = (unsigned long)val;
2648 		}
2649 		*lvalp = jiffies_to_msecs(lval);
2650 	}
2651 	return 0;
2652 }
2653 
2654 /**
2655  * proc_dointvec_jiffies - read a vector of integers as seconds
2656  * @table: the sysctl table
2657  * @write: %TRUE if this is a write to the sysctl file
2658  * @buffer: the user buffer
2659  * @lenp: the size of the user buffer
2660  * @ppos: file position
2661  *
2662  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2663  * values from/to the user buffer, treated as an ASCII string.
2664  * The values read are assumed to be in seconds, and are converted into
2665  * jiffies.
2666  *
2667  * Returns 0 on success.
2668  */
2669 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2670 			  void __user *buffer, size_t *lenp, loff_t *ppos)
2671 {
2672     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2673 		    	    do_proc_dointvec_jiffies_conv,NULL);
2674 }
2675 
2676 /**
2677  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2678  * @table: the sysctl table
2679  * @write: %TRUE if this is a write to the sysctl file
2680  * @buffer: the user buffer
2681  * @lenp: the size of the user buffer
2682  * @ppos: pointer to the file position
2683  *
2684  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2685  * values from/to the user buffer, treated as an ASCII string.
2686  * The values read are assumed to be in 1/USER_HZ seconds, and
2687  * are converted into jiffies.
2688  *
2689  * Returns 0 on success.
2690  */
2691 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2692 				 void __user *buffer, size_t *lenp, loff_t *ppos)
2693 {
2694     return do_proc_dointvec(table,write,buffer,lenp,ppos,
2695 		    	    do_proc_dointvec_userhz_jiffies_conv,NULL);
2696 }
2697 
2698 /**
2699  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2700  * @table: the sysctl table
2701  * @write: %TRUE if this is a write to the sysctl file
2702  * @buffer: the user buffer
2703  * @lenp: the size of the user buffer
2704  * @ppos: file position
2705  * @ppos: the current position in the file
2706  *
2707  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2708  * values from/to the user buffer, treated as an ASCII string.
2709  * The values read are assumed to be in 1/1000 seconds, and
2710  * are converted into jiffies.
2711  *
2712  * Returns 0 on success.
2713  */
2714 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2715 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2716 {
2717 	return do_proc_dointvec(table, write, buffer, lenp, ppos,
2718 				do_proc_dointvec_ms_jiffies_conv, NULL);
2719 }
2720 
2721 static int proc_do_cad_pid(struct ctl_table *table, int write,
2722 			   void __user *buffer, size_t *lenp, loff_t *ppos)
2723 {
2724 	struct pid *new_pid;
2725 	pid_t tmp;
2726 	int r;
2727 
2728 	tmp = pid_vnr(cad_pid);
2729 
2730 	r = __do_proc_dointvec(&tmp, table, write, buffer,
2731 			       lenp, ppos, NULL, NULL);
2732 	if (r || !write)
2733 		return r;
2734 
2735 	new_pid = find_get_pid(tmp);
2736 	if (!new_pid)
2737 		return -ESRCH;
2738 
2739 	put_pid(xchg(&cad_pid, new_pid));
2740 	return 0;
2741 }
2742 
2743 /**
2744  * proc_do_large_bitmap - read/write from/to a large bitmap
2745  * @table: the sysctl table
2746  * @write: %TRUE if this is a write to the sysctl file
2747  * @buffer: the user buffer
2748  * @lenp: the size of the user buffer
2749  * @ppos: file position
2750  *
2751  * The bitmap is stored at table->data and the bitmap length (in bits)
2752  * in table->maxlen.
2753  *
2754  * We use a range comma separated format (e.g. 1,3-4,10-10) so that
2755  * large bitmaps may be represented in a compact manner. Writing into
2756  * the file will clear the bitmap then update it with the given input.
2757  *
2758  * Returns 0 on success.
2759  */
2760 int proc_do_large_bitmap(struct ctl_table *table, int write,
2761 			 void __user *buffer, size_t *lenp, loff_t *ppos)
2762 {
2763 	int err = 0;
2764 	bool first = 1;
2765 	size_t left = *lenp;
2766 	unsigned long bitmap_len = table->maxlen;
2767 	unsigned long *bitmap = (unsigned long *) table->data;
2768 	unsigned long *tmp_bitmap = NULL;
2769 	char tr_a[] = { '-', ',', '\n' }, tr_b[] = { ',', '\n', 0 }, c;
2770 
2771 	if (!bitmap_len || !left || (*ppos && !write)) {
2772 		*lenp = 0;
2773 		return 0;
2774 	}
2775 
2776 	if (write) {
2777 		unsigned long page = 0;
2778 		char *kbuf;
2779 
2780 		if (left > PAGE_SIZE - 1)
2781 			left = PAGE_SIZE - 1;
2782 
2783 		page = __get_free_page(GFP_TEMPORARY);
2784 		kbuf = (char *) page;
2785 		if (!kbuf)
2786 			return -ENOMEM;
2787 		if (copy_from_user(kbuf, buffer, left)) {
2788 			free_page(page);
2789 			return -EFAULT;
2790                 }
2791 		kbuf[left] = 0;
2792 
2793 		tmp_bitmap = kzalloc(BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long),
2794 				     GFP_KERNEL);
2795 		if (!tmp_bitmap) {
2796 			free_page(page);
2797 			return -ENOMEM;
2798 		}
2799 		proc_skip_char(&kbuf, &left, '\n');
2800 		while (!err && left) {
2801 			unsigned long val_a, val_b;
2802 			bool neg;
2803 
2804 			err = proc_get_long(&kbuf, &left, &val_a, &neg, tr_a,
2805 					     sizeof(tr_a), &c);
2806 			if (err)
2807 				break;
2808 			if (val_a >= bitmap_len || neg) {
2809 				err = -EINVAL;
2810 				break;
2811 			}
2812 
2813 			val_b = val_a;
2814 			if (left) {
2815 				kbuf++;
2816 				left--;
2817 			}
2818 
2819 			if (c == '-') {
2820 				err = proc_get_long(&kbuf, &left, &val_b,
2821 						     &neg, tr_b, sizeof(tr_b),
2822 						     &c);
2823 				if (err)
2824 					break;
2825 				if (val_b >= bitmap_len || neg ||
2826 				    val_a > val_b) {
2827 					err = -EINVAL;
2828 					break;
2829 				}
2830 				if (left) {
2831 					kbuf++;
2832 					left--;
2833 				}
2834 			}
2835 
2836 			while (val_a <= val_b)
2837 				set_bit(val_a++, tmp_bitmap);
2838 
2839 			first = 0;
2840 			proc_skip_char(&kbuf, &left, '\n');
2841 		}
2842 		free_page(page);
2843 	} else {
2844 		unsigned long bit_a, bit_b = 0;
2845 
2846 		while (left) {
2847 			bit_a = find_next_bit(bitmap, bitmap_len, bit_b);
2848 			if (bit_a >= bitmap_len)
2849 				break;
2850 			bit_b = find_next_zero_bit(bitmap, bitmap_len,
2851 						   bit_a + 1) - 1;
2852 
2853 			if (!first) {
2854 				err = proc_put_char(&buffer, &left, ',');
2855 				if (err)
2856 					break;
2857 			}
2858 			err = proc_put_long(&buffer, &left, bit_a, false);
2859 			if (err)
2860 				break;
2861 			if (bit_a != bit_b) {
2862 				err = proc_put_char(&buffer, &left, '-');
2863 				if (err)
2864 					break;
2865 				err = proc_put_long(&buffer, &left, bit_b, false);
2866 				if (err)
2867 					break;
2868 			}
2869 
2870 			first = 0; bit_b++;
2871 		}
2872 		if (!err)
2873 			err = proc_put_char(&buffer, &left, '\n');
2874 	}
2875 
2876 	if (!err) {
2877 		if (write) {
2878 			if (*ppos)
2879 				bitmap_or(bitmap, bitmap, tmp_bitmap, bitmap_len);
2880 			else
2881 				memcpy(bitmap, tmp_bitmap,
2882 					BITS_TO_LONGS(bitmap_len) * sizeof(unsigned long));
2883 		}
2884 		kfree(tmp_bitmap);
2885 		*lenp -= left;
2886 		*ppos += *lenp;
2887 		return 0;
2888 	} else {
2889 		kfree(tmp_bitmap);
2890 		return err;
2891 	}
2892 }
2893 
2894 #else /* CONFIG_PROC_FS */
2895 
2896 int proc_dostring(struct ctl_table *table, int write,
2897 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2898 {
2899 	return -ENOSYS;
2900 }
2901 
2902 int proc_dointvec(struct ctl_table *table, int write,
2903 		  void __user *buffer, size_t *lenp, loff_t *ppos)
2904 {
2905 	return -ENOSYS;
2906 }
2907 
2908 int proc_dointvec_minmax(struct ctl_table *table, int write,
2909 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2910 {
2911 	return -ENOSYS;
2912 }
2913 
2914 int proc_dointvec_jiffies(struct ctl_table *table, int write,
2915 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2916 {
2917 	return -ENOSYS;
2918 }
2919 
2920 int proc_dointvec_userhz_jiffies(struct ctl_table *table, int write,
2921 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2922 {
2923 	return -ENOSYS;
2924 }
2925 
2926 int proc_dointvec_ms_jiffies(struct ctl_table *table, int write,
2927 			     void __user *buffer, size_t *lenp, loff_t *ppos)
2928 {
2929 	return -ENOSYS;
2930 }
2931 
2932 int proc_doulongvec_minmax(struct ctl_table *table, int write,
2933 		    void __user *buffer, size_t *lenp, loff_t *ppos)
2934 {
2935 	return -ENOSYS;
2936 }
2937 
2938 int proc_doulongvec_ms_jiffies_minmax(struct ctl_table *table, int write,
2939 				      void __user *buffer,
2940 				      size_t *lenp, loff_t *ppos)
2941 {
2942     return -ENOSYS;
2943 }
2944 
2945 
2946 #endif /* CONFIG_PROC_FS */
2947 
2948 /*
2949  * No sense putting this after each symbol definition, twice,
2950  * exception granted :-)
2951  */
2952 EXPORT_SYMBOL(proc_dointvec);
2953 EXPORT_SYMBOL(proc_dointvec_jiffies);
2954 EXPORT_SYMBOL(proc_dointvec_minmax);
2955 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2956 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2957 EXPORT_SYMBOL(proc_dostring);
2958 EXPORT_SYMBOL(proc_doulongvec_minmax);
2959 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2960 EXPORT_SYMBOL(register_sysctl_table);
2961 EXPORT_SYMBOL(register_sysctl_paths);
2962 EXPORT_SYMBOL(unregister_sysctl_table);
2963