sysctl.c 62.7 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
/*
 * sysctl.c: General linux system control interface
 *
 * Begun 24 March 1995, Stephen Tweedie
 * Added /proc support, Dec 1995
 * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
 * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
 * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
 * Dynamic registration fixes, Stephen Tweedie.
 * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
 * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
 *  Horn.
 * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
 * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
 * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
 *  Wendling.
 * The list_for_each() macro wasn't appropriate for the sysctl loop.
 *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
 */

#include <linux/module.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/sysctl.h>
#include <linux/proc_fs.h>
27
#include <linux/capability.h>
Linus Torvalds's avatar
Linus Torvalds committed
28 29 30 31 32 33
#include <linux/ctype.h>
#include <linux/utsname.h>
#include <linux/capability.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/kernel.h>
34
#include <linux/kobject.h>
35
#include <linux/net.h>
Linus Torvalds's avatar
Linus Torvalds committed
36 37 38 39 40 41 42 43 44 45
#include <linux/sysrq.h>
#include <linux/highuid.h>
#include <linux/writeback.h>
#include <linux/hugetlb.h>
#include <linux/security.h>
#include <linux/initrd.h>
#include <linux/times.h>
#include <linux/limits.h>
#include <linux/dcache.h>
#include <linux/syscalls.h>
46 47
#include <linux/nfs_fs.h>
#include <linux/acpi.h>
Linus Torvalds's avatar
Linus Torvalds committed
48 49 50 51

#include <asm/uaccess.h>
#include <asm/processor.h>

Dipankar Sarma's avatar
Dipankar Sarma committed
52 53 54
extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
                     void __user *buffer, size_t *lenp, loff_t *ppos);

55 56
#ifdef CONFIG_X86
#include <asm/nmi.h>
57
#include <asm/stacktrace.h>
58 59
#endif

Linus Torvalds's avatar
Linus Torvalds committed
60 61 62 63 64 65
#if defined(CONFIG_SYSCTL)

/* External variables not in a header file. */
extern int C_A_D;
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
66
extern int sysctl_panic_on_oom;
Linus Torvalds's avatar
Linus Torvalds committed
67 68 69
extern int max_threads;
extern int sysrq_enabled;
extern int core_uses_pid;
Alan Cox's avatar
Alan Cox committed
70
extern int suid_dumpable;
Linus Torvalds's avatar
Linus Torvalds committed
71 72 73 74 75 76
extern char core_pattern[];
extern int pid_max;
extern int min_free_kbytes;
extern int printk_ratelimit_jiffies;
extern int printk_ratelimit_burst;
extern int pid_max_min, pid_max_max;
Andrew Morton's avatar
Andrew Morton committed
77
extern int sysctl_drop_caches;
78
extern int percpu_pagelist_fraction;
79
extern int compat_log;
Linus Torvalds's avatar
Linus Torvalds committed
80 81 82 83

/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
static int maxolduid = 65535;
static int minolduid;
84
static int min_percpu_pagelist_fract = 8;
Linus Torvalds's avatar
Linus Torvalds committed
85 86 87 88 89 90 91 92 93 94

static int ngroups_max = NGROUPS_MAX;

#ifdef CONFIG_KMOD
extern char modprobe_path[];
#endif
#ifdef CONFIG_CHR_DEV_SG
extern int sg_big_buff;
#endif
#ifdef CONFIG_SYSVIPC
95 96
static int proc_do_ipc_string(ctl_table *table, int write, struct file *filp,
		void __user *buffer, size_t *lenp, loff_t *ppos);
Linus Torvalds's avatar
Linus Torvalds committed
97 98 99 100 101 102 103 104 105 106 107 108 109
#endif

#ifdef __sparc__
extern char reboot_command [];
extern int stop_a_enabled;
extern int scons_pwroff;
#endif

#ifdef __hppa__
extern int pwrsw_enabled;
extern int unaligned_enabled;
#endif

110
#ifdef CONFIG_S390
Linus Torvalds's avatar
Linus Torvalds committed
111 112 113 114
#ifdef CONFIG_MATHEMU
extern int sysctl_ieee_emulation_warnings;
#endif
extern int sysctl_userprocess_debug;
115
extern int spin_retry;
Linus Torvalds's avatar
Linus Torvalds committed
116 117 118 119 120 121 122 123
#endif

extern int sysctl_hz_timer;

#ifdef CONFIG_BSD_PROCESS_ACCT
extern int acct_parm[];
#endif

124 125 126 127
#ifdef CONFIG_IA64
extern int no_unaligned_warning;
#endif

Ingo Molnar's avatar
Ingo Molnar committed
128 129 130 131
#ifdef CONFIG_RT_MUTEXES
extern int max_lock_depth;
#endif

132 133 134 135 136
#ifdef CONFIG_SYSCTL_SYSCALL
static int parse_table(int __user *, int, void __user *, size_t __user *,
		void __user *, size_t, ctl_table *, void **);
#endif

137
static int proc_do_uts_string(ctl_table *table, int write, struct file *filp,
Linus Torvalds's avatar
Linus Torvalds committed
138 139
		  void __user *buffer, size_t *lenp, loff_t *ppos);

140
#ifdef CONFIG_PROC_SYSCTL
141 142
static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
		  void __user *buffer, size_t *lenp, loff_t *ppos);
143
#endif
144

Linus Torvalds's avatar
Linus Torvalds committed
145 146 147 148 149 150 151 152 153 154 155 156 157
static ctl_table root_table[];
static struct ctl_table_header root_table_header =
	{ root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };

static ctl_table kern_table[];
static ctl_table vm_table[];
static ctl_table fs_table[];
static ctl_table debug_table[];
static ctl_table dev_table[];
extern ctl_table random_table[];
#ifdef CONFIG_UNIX98_PTYS
extern ctl_table pty_table[];
#endif
158
#ifdef CONFIG_INOTIFY_USER
Robert Love's avatar
Robert Love committed
159 160
extern ctl_table inotify_table[];
#endif
Linus Torvalds's avatar
Linus Torvalds committed
161 162 163 164 165

#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
int sysctl_legacy_va_layout;
#endif

166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187
static void *get_uts(ctl_table *table, int write)
{
	char *which = table->data;
#ifdef CONFIG_UTS_NS
	struct uts_namespace *uts_ns = current->nsproxy->uts_ns;
	which = (which - (char *)&init_uts_ns) + (char *)uts_ns;
#endif
	if (!write)
		down_read(&uts_sem);
	else
		down_write(&uts_sem);
	return which;
}

static void put_uts(ctl_table *table, int write, void *which)
{
	if (!write)
		up_read(&uts_sem);
	else
		up_write(&uts_sem);
}

Linus Torvalds's avatar
Linus Torvalds committed
188 189
/* /proc declarations: */

190
#ifdef CONFIG_PROC_SYSCTL
Linus Torvalds's avatar
Linus Torvalds committed
191 192 193 194 195

static ssize_t proc_readsys(struct file *, char __user *, size_t, loff_t *);
static ssize_t proc_writesys(struct file *, const char __user *, size_t, loff_t *);
static int proc_opensys(struct inode *, struct file *);

196
const struct file_operations proc_sys_file_operations = {
Linus Torvalds's avatar
Linus Torvalds committed
197 198 199 200 201 202 203
	.open		= proc_opensys,
	.read		= proc_readsys,
	.write		= proc_writesys,
};

extern struct proc_dir_entry *proc_sys_root;

204
static void register_proc_table(ctl_table *, struct proc_dir_entry *, void *);
Linus Torvalds's avatar
Linus Torvalds committed
205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248
static void unregister_proc_table(ctl_table *, struct proc_dir_entry *);
#endif

/* The default sysctl tables: */

static ctl_table root_table[] = {
	{
		.ctl_name	= CTL_KERN,
		.procname	= "kernel",
		.mode		= 0555,
		.child		= kern_table,
	},
	{
		.ctl_name	= CTL_VM,
		.procname	= "vm",
		.mode		= 0555,
		.child		= vm_table,
	},
#ifdef CONFIG_NET
	{
		.ctl_name	= CTL_NET,
		.procname	= "net",
		.mode		= 0555,
		.child		= net_table,
	},
#endif
	{
		.ctl_name	= CTL_FS,
		.procname	= "fs",
		.mode		= 0555,
		.child		= fs_table,
	},
	{
		.ctl_name	= CTL_DEBUG,
		.procname	= "debug",
		.mode		= 0555,
		.child		= debug_table,
	},
	{
		.ctl_name	= CTL_DEV,
		.procname	= "dev",
		.mode		= 0555,
		.child		= dev_table,
	},
Robert Love's avatar
Robert Love committed
249

Linus Torvalds's avatar
Linus Torvalds committed
250 251 252 253 254 255 256
	{ .ctl_name = 0 }
};

static ctl_table kern_table[] = {
	{
		.ctl_name	= KERN_OSTYPE,
		.procname	= "ostype",
257 258
		.data		= init_uts_ns.name.sysname,
		.maxlen		= sizeof(init_uts_ns.name.sysname),
Linus Torvalds's avatar
Linus Torvalds committed
259
		.mode		= 0444,
260
		.proc_handler	= &proc_do_uts_string,
Linus Torvalds's avatar
Linus Torvalds committed
261 262 263 264 265
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_OSRELEASE,
		.procname	= "osrelease",
266 267
		.data		= init_uts_ns.name.release,
		.maxlen		= sizeof(init_uts_ns.name.release),
Linus Torvalds's avatar
Linus Torvalds committed
268
		.mode		= 0444,
269
		.proc_handler	= &proc_do_uts_string,
Linus Torvalds's avatar
Linus Torvalds committed
270 271 272 273 274
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_VERSION,
		.procname	= "version",
275 276
		.data		= init_uts_ns.name.version,
		.maxlen		= sizeof(init_uts_ns.name.version),
Linus Torvalds's avatar
Linus Torvalds committed
277
		.mode		= 0444,
278
		.proc_handler	= &proc_do_uts_string,
Linus Torvalds's avatar
Linus Torvalds committed
279 280 281 282 283
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_NODENAME,
		.procname	= "hostname",
284 285
		.data		= init_uts_ns.name.nodename,
		.maxlen		= sizeof(init_uts_ns.name.nodename),
Linus Torvalds's avatar
Linus Torvalds committed
286
		.mode		= 0644,
287
		.proc_handler	= &proc_do_uts_string,
Linus Torvalds's avatar
Linus Torvalds committed
288 289 290 291 292
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_DOMAINNAME,
		.procname	= "domainname",
293 294
		.data		= init_uts_ns.name.domainname,
		.maxlen		= sizeof(init_uts_ns.name.domainname),
Linus Torvalds's avatar
Linus Torvalds committed
295
		.mode		= 0644,
296
		.proc_handler	= &proc_do_uts_string,
Linus Torvalds's avatar
Linus Torvalds committed
297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_PANIC,
		.procname	= "panic",
		.data		= &panic_timeout,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_CORE_USES_PID,
		.procname	= "core_uses_pid",
		.data		= &core_uses_pid,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_CORE_PATTERN,
		.procname	= "core_pattern",
		.data		= core_pattern,
319
		.maxlen		= 128,
Linus Torvalds's avatar
Linus Torvalds committed
320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421
		.mode		= 0644,
		.proc_handler	= &proc_dostring,
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_TAINTED,
		.procname	= "tainted",
		.data		= &tainted,
		.maxlen		= sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_CAP_BSET,
		.procname	= "cap-bound",
		.data		= &cap_bset,
		.maxlen		= sizeof(kernel_cap_t),
		.mode		= 0600,
		.proc_handler	= &proc_dointvec_bset,
	},
#ifdef CONFIG_BLK_DEV_INITRD
	{
		.ctl_name	= KERN_REALROOTDEV,
		.procname	= "real-root-dev",
		.data		= &real_root_dev,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
#ifdef __sparc__
	{
		.ctl_name	= KERN_SPARC_REBOOT,
		.procname	= "reboot-cmd",
		.data		= reboot_command,
		.maxlen		= 256,
		.mode		= 0644,
		.proc_handler	= &proc_dostring,
		.strategy	= &sysctl_string,
	},
	{
		.ctl_name	= KERN_SPARC_STOP_A,
		.procname	= "stop-a",
		.data		= &stop_a_enabled,
		.maxlen		= sizeof (int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_SPARC_SCONS_PWROFF,
		.procname	= "scons-poweroff",
		.data		= &scons_pwroff,
		.maxlen		= sizeof (int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
#ifdef __hppa__
	{
		.ctl_name	= KERN_HPPA_PWRSW,
		.procname	= "soft-power",
		.data		= &pwrsw_enabled,
		.maxlen		= sizeof (int),
	 	.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_HPPA_UNALIGNED,
		.procname	= "unaligned-trap",
		.data		= &unaligned_enabled,
		.maxlen		= sizeof (int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
	{
		.ctl_name	= KERN_CTLALTDEL,
		.procname	= "ctrl-alt-del",
		.data		= &C_A_D,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_PRINTK,
		.procname	= "printk",
		.data		= &console_loglevel,
		.maxlen		= 4*sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#ifdef CONFIG_KMOD
	{
		.ctl_name	= KERN_MODPROBE,
		.procname	= "modprobe",
		.data		= &modprobe_path,
		.maxlen		= KMOD_PATH_LEN,
		.mode		= 0644,
		.proc_handler	= &proc_dostring,
		.strategy	= &sysctl_string,
	},
#endif
Andrew Morton's avatar
Andrew Morton committed
422
#if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
Linus Torvalds's avatar
Linus Torvalds committed
423 424 425
	{
		.ctl_name	= KERN_HOTPLUG,
		.procname	= "hotplug",
426 427
		.data		= &uevent_helper,
		.maxlen		= UEVENT_HELPER_PATH_LEN,
Linus Torvalds's avatar
Linus Torvalds committed
428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456
		.mode		= 0644,
		.proc_handler	= &proc_dostring,
		.strategy	= &sysctl_string,
	},
#endif
#ifdef CONFIG_CHR_DEV_SG
	{
		.ctl_name	= KERN_SG_BIG_BUFF,
		.procname	= "sg-big-buff",
		.data		= &sg_big_buff,
		.maxlen		= sizeof (int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
#endif
#ifdef CONFIG_BSD_PROCESS_ACCT
	{
		.ctl_name	= KERN_ACCT,
		.procname	= "acct",
		.data		= &acct_parm,
		.maxlen		= 3*sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
#ifdef CONFIG_SYSVIPC
	{
		.ctl_name	= KERN_SHMMAX,
		.procname	= "shmmax",
457
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
458 459
		.maxlen		= sizeof (size_t),
		.mode		= 0644,
460
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
461 462 463 464
	},
	{
		.ctl_name	= KERN_SHMALL,
		.procname	= "shmall",
465
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
466 467
		.maxlen		= sizeof (size_t),
		.mode		= 0644,
468
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
469 470 471 472
	},
	{
		.ctl_name	= KERN_SHMMNI,
		.procname	= "shmmni",
473
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
474 475
		.maxlen		= sizeof (int),
		.mode		= 0644,
476
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
477 478 479 480
	},
	{
		.ctl_name	= KERN_MSGMAX,
		.procname	= "msgmax",
481
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
482 483
		.maxlen		= sizeof (int),
		.mode		= 0644,
484
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
485 486 487 488
	},
	{
		.ctl_name	= KERN_MSGMNI,
		.procname	= "msgmni",
489
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
490 491
		.maxlen		= sizeof (int),
		.mode		= 0644,
492
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
493 494 495 496
	},
	{
		.ctl_name	= KERN_MSGMNB,
		.procname	=  "msgmnb",
497
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
498 499
		.maxlen		= sizeof (int),
		.mode		= 0644,
500
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
501 502 503 504
	},
	{
		.ctl_name	= KERN_SEM,
		.procname	= "sem",
505
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
506 507
		.maxlen		= 4*sizeof (int),
		.mode		= 0644,
508
		.proc_handler	= &proc_do_ipc_string,
Linus Torvalds's avatar
Linus Torvalds committed
509 510 511 512 513 514 515 516 517 518 519 520
	},
#endif
#ifdef CONFIG_MAGIC_SYSRQ
	{
		.ctl_name	= KERN_SYSRQ,
		.procname	= "sysrq",
		.data		= &sysrq_enabled,
		.maxlen		= sizeof (int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
521
#ifdef CONFIG_PROC_SYSCTL
Linus Torvalds's avatar
Linus Torvalds committed
522 523 524
	{
		.ctl_name	= KERN_CADPID,
		.procname	= "cad_pid",
525
		.data		= NULL,
Linus Torvalds's avatar
Linus Torvalds committed
526 527
		.maxlen		= sizeof (int),
		.mode		= 0600,
528
		.proc_handler	= &proc_do_cad_pid,
Linus Torvalds's avatar
Linus Torvalds committed
529
	},
530
#endif
Linus Torvalds's avatar
Linus Torvalds committed
531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574
	{
		.ctl_name	= KERN_MAX_THREADS,
		.procname	= "threads-max",
		.data		= &max_threads,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_RANDOM,
		.procname	= "random",
		.mode		= 0555,
		.child		= random_table,
	},
#ifdef CONFIG_UNIX98_PTYS
	{
		.ctl_name	= KERN_PTY,
		.procname	= "pty",
		.mode		= 0555,
		.child		= pty_table,
	},
#endif
	{
		.ctl_name	= KERN_OVERFLOWUID,
		.procname	= "overflowuid",
		.data		= &overflowuid,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &minolduid,
		.extra2		= &maxolduid,
	},
	{
		.ctl_name	= KERN_OVERFLOWGID,
		.procname	= "overflowgid",
		.data		= &overflowgid,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &minolduid,
		.extra2		= &maxolduid,
	},
575
#ifdef CONFIG_S390
Linus Torvalds's avatar
Linus Torvalds committed
576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655
#ifdef CONFIG_MATHEMU
	{
		.ctl_name	= KERN_IEEE_EMULATION_WARNINGS,
		.procname	= "ieee_emulation_warnings",
		.data		= &sysctl_ieee_emulation_warnings,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
#ifdef CONFIG_NO_IDLE_HZ
	{
		.ctl_name       = KERN_HZ_TIMER,
		.procname       = "hz_timer",
		.data           = &sysctl_hz_timer,
		.maxlen         = sizeof(int),
		.mode           = 0644,
		.proc_handler   = &proc_dointvec,
	},
#endif
	{
		.ctl_name	= KERN_S390_USER_DEBUG_LOGGING,
		.procname	= "userprocess_debug",
		.data		= &sysctl_userprocess_debug,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
	{
		.ctl_name	= KERN_PIDMAX,
		.procname	= "pid_max",
		.data		= &pid_max,
		.maxlen		= sizeof (int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= sysctl_intvec,
		.extra1		= &pid_max_min,
		.extra2		= &pid_max_max,
	},
	{
		.ctl_name	= KERN_PANIC_ON_OOPS,
		.procname	= "panic_on_oops",
		.data		= &panic_on_oops,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_PRINTK_RATELIMIT,
		.procname	= "printk_ratelimit",
		.data		= &printk_ratelimit_jiffies,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
	},
	{
		.ctl_name	= KERN_PRINTK_RATELIMIT_BURST,
		.procname	= "printk_ratelimit_burst",
		.data		= &printk_ratelimit_burst,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= KERN_NGROUPS_MAX,
		.procname	= "ngroups_max",
		.data		= &ngroups_max,
		.maxlen		= sizeof (int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
	{
		.ctl_name       = KERN_UNKNOWN_NMI_PANIC,
		.procname       = "unknown_nmi_panic",
		.data           = &unknown_nmi_panic,
		.maxlen         = sizeof (int),
		.mode           = 0644,
656
		.proc_handler   = &proc_dointvec,
Linus Torvalds's avatar
Linus Torvalds committed
657
	},
658 659 660 661 662 663 664
	{
		.ctl_name       = KERN_NMI_WATCHDOG,
		.procname       = "nmi_watchdog",
		.data           = &nmi_watchdog_enabled,
		.maxlen         = sizeof (int),
		.mode           = 0644,
		.proc_handler   = &proc_nmi_enabled,
Linus Torvalds's avatar
Linus Torvalds committed
665 666 667
	},
#endif
#if defined(CONFIG_X86)
668 669 670 671 672 673 674 675
	{
		.ctl_name	= KERN_PANIC_ON_NMI,
		.procname	= "panic_on_unrecovered_nmi",
		.data		= &panic_on_unrecovered_nmi,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
Linus Torvalds's avatar
Linus Torvalds committed
676 677 678 679 680 681 682 683
	{
		.ctl_name	= KERN_BOOTLOADER_TYPE,
		.procname	= "bootloader_type",
		.data		= &bootloader_type,
		.maxlen		= sizeof (int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
684 685 686 687 688 689 690 691
	{
		.ctl_name	= CTL_UNNUMBERED,
		.procname	= "kstack_depth_to_print",
		.data		= &kstack_depth_to_print,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
Linus Torvalds's avatar
Linus Torvalds committed
692
#endif
693
#if defined(CONFIG_MMU)
Linus Torvalds's avatar
Linus Torvalds committed
694 695 696 697 698 699 700 701
	{
		.ctl_name	= KERN_RANDOMIZE,
		.procname	= "randomize_va_space",
		.data		= &randomize_va_space,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
702
#endif
703
#if defined(CONFIG_S390) && defined(CONFIG_SMP)
704 705 706 707 708 709 710 711
	{
		.ctl_name	= KERN_SPIN_RETRY,
		.procname	= "spin_retry",
		.data		= &spin_retry,
		.maxlen		= sizeof (int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
712 713 714 715 716 717 718 719
#endif
#ifdef CONFIG_ACPI_SLEEP
	{
		.ctl_name	= KERN_ACPI_VIDEO_FLAGS,
		.procname	= "acpi_video_flags",
		.data		= &acpi_video_flags,
		.maxlen		= sizeof (unsigned long),
		.mode		= 0644,
720
		.proc_handler	= &proc_doulongvec_minmax,
721
	},
722 723 724 725 726 727 728 729 730 731
#endif
#ifdef CONFIG_IA64
	{
		.ctl_name	= KERN_IA64_UNALIGNED,
		.procname	= "ignore-unaligned-usertrap",
		.data		= &no_unaligned_warning,
		.maxlen		= sizeof (int),
	 	.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
732 733 734 735 736 737 738 739 740 741
#endif
#ifdef CONFIG_COMPAT
	{
		.ctl_name	= KERN_COMPAT_LOG,
		.procname	= "compat-log",
		.data		= &compat_log,
		.maxlen		= sizeof (int),
	 	.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
742
#endif
Ingo Molnar's avatar
Ingo Molnar committed
743 744 745 746 747 748 749 750 751 752 753
#ifdef CONFIG_RT_MUTEXES
	{
		.ctl_name	= KERN_MAX_LOCK_DEPTH,
		.procname	= "max_lock_depth",
		.data		= &max_lock_depth,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif

Linus Torvalds's avatar
Linus Torvalds committed
754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771
	{ .ctl_name = 0 }
};

/* Constants for minimum and maximum testing in vm_table.
   We use these as one-element integer vectors. */
static int zero;
static int one_hundred = 100;


static ctl_table vm_table[] = {
	{
		.ctl_name	= VM_OVERCOMMIT_MEMORY,
		.procname	= "overcommit_memory",
		.data		= &sysctl_overcommit_memory,
		.maxlen		= sizeof(sysctl_overcommit_memory),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
772 773 774 775 776 777 778 779
	{
		.ctl_name	= VM_PANIC_ON_OOM,
		.procname	= "panic_on_oom",
		.data		= &sysctl_panic_on_oom,
		.maxlen		= sizeof(sysctl_panic_on_oom),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
Linus Torvalds's avatar
Linus Torvalds committed
780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820
	{
		.ctl_name	= VM_OVERCOMMIT_RATIO,
		.procname	= "overcommit_ratio",
		.data		= &sysctl_overcommit_ratio,
		.maxlen		= sizeof(sysctl_overcommit_ratio),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= VM_PAGE_CLUSTER,
		.procname	= "page-cluster", 
		.data		= &page_cluster,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= VM_DIRTY_BACKGROUND,
		.procname	= "dirty_background_ratio",
		.data		= &dirty_background_ratio,
		.maxlen		= sizeof(dirty_background_ratio),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
		.extra2		= &one_hundred,
	},
	{
		.ctl_name	= VM_DIRTY_RATIO,
		.procname	= "dirty_ratio",
		.data		= &vm_dirty_ratio,
		.maxlen		= sizeof(vm_dirty_ratio),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
		.extra2		= &one_hundred,
	},
	{
		.ctl_name	= VM_DIRTY_WB_CS,
		.procname	= "dirty_writeback_centisecs",
821 822
		.data		= &dirty_writeback_interval,
		.maxlen		= sizeof(dirty_writeback_interval),
Linus Torvalds's avatar
Linus Torvalds committed
823 824 825 826 827 828
		.mode		= 0644,
		.proc_handler	= &dirty_writeback_centisecs_handler,
	},
	{
		.ctl_name	= VM_DIRTY_EXPIRE_CS,
		.procname	= "dirty_expire_centisecs",
829 830
		.data		= &dirty_expire_interval,
		.maxlen		= sizeof(dirty_expire_interval),
Linus Torvalds's avatar
Linus Torvalds committed
831
		.mode		= 0644,
832
		.proc_handler	= &proc_dointvec_userhz_jiffies,
Linus Torvalds's avatar
Linus Torvalds committed
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881
	},
	{
		.ctl_name	= VM_NR_PDFLUSH_THREADS,
		.procname	= "nr_pdflush_threads",
		.data		= &nr_pdflush_threads,
		.maxlen		= sizeof nr_pdflush_threads,
		.mode		= 0444 /* read-only*/,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= VM_SWAPPINESS,
		.procname	= "swappiness",
		.data		= &vm_swappiness,
		.maxlen		= sizeof(vm_swappiness),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
		.extra2		= &one_hundred,
	},
#ifdef CONFIG_HUGETLB_PAGE
	 {
		.ctl_name	= VM_HUGETLB_PAGES,
		.procname	= "nr_hugepages",
		.data		= &max_huge_pages,
		.maxlen		= sizeof(unsigned long),
		.mode		= 0644,
		.proc_handler	= &hugetlb_sysctl_handler,
		.extra1		= (void *)&hugetlb_zero,
		.extra2		= (void *)&hugetlb_infinity,
	 },
	 {
		.ctl_name	= VM_HUGETLB_GROUP,
		.procname	= "hugetlb_shm_group",
		.data		= &sysctl_hugetlb_shm_group,
		.maxlen		= sizeof(gid_t),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	 },
#endif
	{
		.ctl_name	= VM_LOWMEM_RESERVE_RATIO,
		.procname	= "lowmem_reserve_ratio",
		.data		= &sysctl_lowmem_reserve_ratio,
		.maxlen		= sizeof(sysctl_lowmem_reserve_ratio),
		.mode		= 0644,
		.proc_handler	= &lowmem_reserve_ratio_sysctl_handler,
		.strategy	= &sysctl_intvec,
	},
Andrew Morton's avatar
Andrew Morton committed
882 883 884 885 886 887 888 889 890
	{
		.ctl_name	= VM_DROP_PAGECACHE,
		.procname	= "drop_caches",
		.data		= &sysctl_drop_caches,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= drop_caches_sysctl_handler,
		.strategy	= &sysctl_intvec,
	},
Linus Torvalds's avatar
Linus Torvalds committed
891 892 893 894 895 896 897 898 899 900
	{
		.ctl_name	= VM_MIN_FREE_KBYTES,
		.procname	= "min_free_kbytes",
		.data		= &min_free_kbytes,
		.maxlen		= sizeof(min_free_kbytes),
		.mode		= 0644,
		.proc_handler	= &min_free_kbytes_sysctl_handler,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
	},
901 902 903 904 905 906 907 908 909 910
	{
		.ctl_name	= VM_PERCPU_PAGELIST_FRACTION,
		.procname	= "percpu_pagelist_fraction",
		.data		= &percpu_pagelist_fraction,
		.maxlen		= sizeof(percpu_pagelist_fraction),
		.mode		= 0644,
		.proc_handler	= &percpu_pagelist_fraction_sysctl_handler,
		.strategy	= &sysctl_intvec,
		.extra1		= &min_percpu_pagelist_fract,
	},
Linus Torvalds's avatar
Linus Torvalds committed
911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926
#ifdef CONFIG_MMU
	{
		.ctl_name	= VM_MAX_MAP_COUNT,
		.procname	= "max_map_count",
		.data		= &sysctl_max_map_count,
		.maxlen		= sizeof(sysctl_max_map_count),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec
	},
#endif
	{
		.ctl_name	= VM_LAPTOP_MODE,
		.procname	= "laptop_mode",
		.data		= &laptop_mode,
		.maxlen		= sizeof(laptop_mode),
		.mode		= 0644,
927 928
		.proc_handler	= &proc_dointvec_jiffies,
		.strategy	= &sysctl_jiffies,
Linus Torvalds's avatar
Linus Torvalds committed
929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961
	},
	{
		.ctl_name	= VM_BLOCK_DUMP,
		.procname	= "block_dump",
		.data		= &block_dump,
		.maxlen		= sizeof(block_dump),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
	},
	{
		.ctl_name	= VM_VFS_CACHE_PRESSURE,
		.procname	= "vfs_cache_pressure",
		.data		= &sysctl_vfs_cache_pressure,
		.maxlen		= sizeof(sysctl_vfs_cache_pressure),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
	},
#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
	{
		.ctl_name	= VM_LEGACY_VA_LAYOUT,
		.procname	= "legacy_va_layout",
		.data		= &sysctl_legacy_va_layout,
		.maxlen		= sizeof(sysctl_legacy_va_layout),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
	},
#endif
962 963 964 965 966 967 968 969
#ifdef CONFIG_NUMA
	{
		.ctl_name	= VM_ZONE_RECLAIM_MODE,
		.procname	= "zone_reclaim_mode",
		.data		= &zone_reclaim_mode,
		.maxlen		= sizeof(zone_reclaim_mode),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
970 971
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
972
	},
973 974 975 976 977 978 979 980 981 982 983
	{
		.ctl_name	= VM_MIN_UNMAPPED,
		.procname	= "min_unmapped_ratio",
		.data		= &sysctl_min_unmapped_ratio,
		.maxlen		= sizeof(sysctl_min_unmapped_ratio),
		.mode		= 0644,
		.proc_handler	= &sysctl_min_unmapped_ratio_sysctl_handler,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
		.extra2		= &one_hundred,
	},
984 985 986 987 988 989 990 991 992 993 994
	{
		.ctl_name	= VM_MIN_SLAB,
		.procname	= "min_slab_ratio",
		.data		= &sysctl_min_slab_ratio,
		.maxlen		= sizeof(sysctl_min_slab_ratio),
		.mode		= 0644,
		.proc_handler	= &sysctl_min_slab_ratio_sysctl_handler,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
		.extra2		= &one_hundred,
	},
995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006
#endif
#ifdef CONFIG_X86_32
	{
		.ctl_name	= VM_VDSO_ENABLED,
		.procname	= "vdso_enabled",
		.data		= &vdso_enabled,
		.maxlen		= sizeof(vdso_enabled),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
		.strategy	= &sysctl_intvec,
		.extra1		= &zero,
	},
Linus Torvalds's avatar
Linus Torvalds committed
1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033
#endif
	{ .ctl_name = 0 }
};

static ctl_table fs_table[] = {
	{
		.ctl_name	= FS_NRINODE,
		.procname	= "inode-nr",
		.data		= &inodes_stat,
		.maxlen		= 2*sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_STATINODE,
		.procname	= "inode-state",
		.data		= &inodes_stat,
		.maxlen		= 7*sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_NRFILE,
		.procname	= "file-nr",
		.data		= &files_stat,
		.maxlen		= 3*sizeof(int),
		.mode		= 0444,
Dipankar Sarma's avatar
Dipankar Sarma committed
1034
		.proc_handler	= &proc_nr_files,
Linus Torvalds's avatar
Linus Torvalds committed
1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
	},
	{
		.ctl_name	= FS_MAXFILE,
		.procname	= "file-max",
		.data		= &files_stat.max_files,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_DENTRY,
		.procname	= "dentry-state",
		.data		= &dentry_stat,
		.maxlen		= 6*sizeof(int),
		.mode		= 0444,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_OVERFLOWUID,
		.procname	= "overflowuid",
		.data		= &fs_overflowuid,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &minolduid,
		.extra2		= &maxolduid,
	},
	{
		.ctl_name	= FS_OVERFLOWGID,
		.procname	= "overflowgid",
		.data		= &fs_overflowgid,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec_minmax,
		.strategy	= &sysctl_intvec,
		.extra1		= &minolduid,
		.extra2		= &maxolduid,
	},
	{
		.ctl_name	= FS_LEASES,
		.procname	= "leases-enable",
		.data		= &leases_enable,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#ifdef CONFIG_DNOTIFY
	{
		.ctl_name	= FS_DIR_NOTIFY,
		.procname	= "dir-notify-enable",
		.data		= &dir_notify_enable,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
#endif
#ifdef CONFIG_MMU
	{
		.ctl_name	= FS_LEASE_TIME,
		.procname	= "lease-break-time",
		.data		= &lease_break_time,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
	{
		.ctl_name	= FS_AIO_NR,
		.procname	= "aio-nr",
		.data		= &aio_nr,
		.maxlen		= sizeof(aio_nr),
		.mode		= 0444,
1107
		.proc_handler	= &proc_doulongvec_minmax,
Linus Torvalds's avatar
Linus Torvalds committed
1108 1109 1110 1111 1112 1113 1114
	},
	{
		.ctl_name	= FS_AIO_MAX_NR,
		.procname	= "aio-max-nr",
		.data		= &aio_max_nr,
		.maxlen		= sizeof(aio_max_nr),
		.mode		= 0644,
1115
		.proc_handler	= &proc_doulongvec_minmax,
Linus Torvalds's avatar
Linus Torvalds committed
1116
	},
1117
#ifdef CONFIG_INOTIFY_USER
Robert Love's avatar
Robert Love committed
1118 1119 1120 1121 1122 1123 1124
	{
		.ctl_name	= FS_INOTIFY,
		.procname	= "inotify",
		.mode		= 0555,
		.child		= inotify_table,
	},
#endif	
Linus Torvalds's avatar
Linus Torvalds committed
1125
#endif
Alan Cox's avatar
Alan Cox committed
1126 1127 1128 1129 1130 1131 1132 1133
	{
		.ctl_name	= KERN_SETUID_DUMPABLE,
		.procname	= "suid_dumpable",
		.data		= &suid_dumpable,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= &proc_dointvec,
	},
Linus Torvalds's avatar
Linus Torvalds committed
1134 1135 1136 1137 1138 1139 1140 1141 1142
	{ .ctl_name = 0 }
};

static ctl_table debug_table[] = {
	{ .ctl_name = 0 }
};

static ctl_table dev_table[] = {
	{ .ctl_name = 0 }
Robert Love's avatar
Robert Love committed
1143
};
Linus Torvalds's avatar
Linus Torvalds committed
1144 1145 1146

extern void init_irq_proc (void);

1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
static DEFINE_SPINLOCK(sysctl_lock);

/* called under sysctl_lock */
static int use_table(struct ctl_table_header *p)
{
	if (unlikely(p->unregistering))
		return 0;
	p->used++;
	return 1;
}

/* called under sysctl_lock */
static void unuse_table(struct ctl_table_header *p)
{
	if (!--p->used)
		if (unlikely(p->unregistering))
			complete(p->unregistering);
}

/* called under sysctl_lock, will reacquire if has to wait */
static void start_unregistering(struct ctl_table_header *p)
{
	/*
	 * if p->used is 0, nobody will ever touch that entry again;
	 * we'll eliminate all paths to it before dropping sysctl_lock
	 */
	if (unlikely(p->used)) {
		struct completion wait;
		init_completion(&wait);
		p->unregistering = &wait;
		spin_unlock(&sysctl_lock);
		wait_for_completion(&wait);
		spin_lock(&sysctl_lock);
	}
	/*
	 * do not remove from the list until nobody holds it; walking the
	 * list in do_sysctl() relies on that.
	 */
	list_del_init(&p->ctl_entry);
}

Linus Torvalds's avatar
Linus Torvalds committed
1188 1189
void __init sysctl_init(void)
{
1190
#ifdef CONFIG_PROC_SYSCTL
1191
	register_proc_table(root_table, proc_sys_root, &root_table_header);
Linus Torvalds's avatar
Linus Torvalds committed
1192 1193 1194 1195
	init_irq_proc();
#endif
}

1196
#ifdef CONFIG_SYSCTL_SYSCALL
Linus Torvalds's avatar
Linus Torvalds committed
1197 1198 1199 1200
int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
	       void __user *newval, size_t newlen)
{
	struct list_head *tmp;
1201
	int error = -ENOTDIR;
Linus Torvalds's avatar
Linus Torvalds committed
1202 1203 1204 1205 1206 1207 1208 1209

	if (nlen <= 0 || nlen >= CTL_MAXNAME)
		return -ENOTDIR;
	if (oldval) {
		int old_len;
		if (!oldlenp || get_user(old_len, oldlenp))
			return -EFAULT;
	}
1210
	spin_lock(&sysctl_lock);
Linus Torvalds's avatar
Linus Torvalds committed
1211 1212 1213 1214 1215
	tmp = &root_table_header.ctl_entry;
	do {
		struct ctl_table_header *head =
			list_entry(tmp, struct ctl_table_header, ctl_entry);
		void *context = NULL;
1216 1217 1218 1219 1220 1221 1222

		if (!use_table(head))
			continue;

		spin_unlock(&sysctl_lock);

		error = parse_table(name, nlen, oldval, oldlenp, 
Linus Torvalds's avatar
Linus Torvalds committed
1223 1224
					newval, newlen, head->ctl_table,
					&context);
1225
		kfree(context);
1226 1227 1228

		spin_lock(&sysctl_lock);
		unuse_table(head);
Linus Torvalds's avatar
Linus Torvalds committed
1229
		if (error != -ENOTDIR)
1230 1231 1232 1233
			break;
	} while ((tmp = tmp->next) != &root_table_header.ctl_entry);
	spin_unlock(&sysctl_lock);
	return error;
Linus Torvalds's avatar
Linus Torvalds committed
1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
}

asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
{
	struct __sysctl_args tmp;
	int error;

	if (copy_from_user(&tmp, args, sizeof(tmp)))
		return -EFAULT;

	lock_kernel();
	error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
			  tmp.newval, tmp.newlen);
	unlock_kernel();
	return error;
}
1250
#endif /* CONFIG_SYSCTL_SYSCALL */
Linus Torvalds's avatar
Linus Torvalds committed
1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276

/*
 * ctl_perm does NOT grant the superuser all rights automatically, because
 * some sysctl variables are readonly even to root.
 */

static int test_perm(int mode, int op)
{
	if (!current->euid)
		mode >>= 6;
	else if (in_egroup_p(0))
		mode >>= 3;
	if ((mode & op & 0007) == op)
		return 0;
	return -EACCES;
}

static inline int ctl_perm(ctl_table *table, int op)
{
	int error;
	error = security_sysctl(table, op);
	if (error)
		return error;
	return test_perm(table->mode, op);
}

1277
#ifdef CONFIG_SYSCTL_SYSCALL
Linus Torvalds's avatar
Linus Torvalds committed
1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288
static int parse_table(int __user *name, int nlen,
		       void __user *oldval, size_t __user *oldlenp,
		       void __user *newval, size_t newlen,
		       ctl_table *table, void **context)
{
	int n;
repeat:
	if (!nlen)
		return -ENOTDIR;
	if (get_user(n, name))
		return -EFAULT;
1289 1290 1291
	for ( ; table->ctl_name || table->procname; table++) {
		if (!table->ctl_name)
			continue;
Linus Torvalds's avatar
Linus Torvalds committed
1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368
		if (n == table->ctl_name || table->ctl_name == CTL_ANY) {
			int error;
			if (table->child) {
				if (ctl_perm(table, 001))
					return -EPERM;
				if (table->strategy) {
					error = table->strategy(
						table, name, nlen,
						oldval, oldlenp,
						newval, newlen, context);
					if (error)
						return error;
				}
				name++;
				nlen--;
				table = table->child;
				goto repeat;
			}
			error = do_sysctl_strategy(table, name, nlen,
						   oldval, oldlenp,
						   newval, newlen, context);
			return error;
		}
	}
	return -ENOTDIR;
}

/* Perform the actual read/write of a sysctl table entry. */
int do_sysctl_strategy (ctl_table *table, 
			int __user *name, int nlen,
			void __user *oldval, size_t __user *oldlenp,
			void __user *newval, size_t newlen, void **context)
{
	int op = 0, rc;
	size_t len;

	if (oldval)
		op |= 004;
	if (newval) 
		op |= 002;
	if (ctl_perm(table, op))
		return -EPERM;

	if (table->strategy) {
		rc = table->strategy(table, name, nlen, oldval, oldlenp,
				     newval, newlen, context);
		if (rc < 0)
			return rc;
		if (rc > 0)
			return 0;
	}

	/* If there is no strategy routine, or if the strategy returns
	 * zero, proceed with automatic r/w */
	if (table->data && table->maxlen) {
		if (oldval && oldlenp) {
			if (get_user(len, oldlenp))
				return -EFAULT;
			if (len) {
				if (len > table->maxlen)
					len = table->maxlen;
				if(copy_to_user(oldval, table->data, len))
					return -EFAULT;
				if(put_user(len, oldlenp))
					return -EFAULT;
			}
		}
		if (newval && newlen) {
			len = newlen;
			if (len > table->maxlen)
				len = table->maxlen;
			if(copy_from_user(table->data, newval, len))
				return -EFAULT;
		}
	}
	return 0;
}
1369
#endif /* CONFIG_SYSCTL_SYSCALL */
Linus Torvalds's avatar
Linus Torvalds committed
1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448

/**
 * register_sysctl_table - register a sysctl hierarchy
 * @table: the top-level table structure
 * @insert_at_head: whether the entry should be inserted in front or at the end
 *
 * Register a sysctl table hierarchy. @table should be a filled in ctl_table
 * array. An entry with a ctl_name of 0 terminates the table. 
 *
 * The members of the &ctl_table structure are used as follows:
 *
 * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
 *            must be unique within that level of sysctl
 *
 * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
 *            enter a sysctl file
 *
 * data - a pointer to data for use by proc_handler
 *
 * maxlen - the maximum size in bytes of the data
 *
 * mode - the file permissions for the /proc/sys file, and for sysctl(2)
 *
 * child - a pointer to the child sysctl table if this entry is a directory, or
 *         %NULL.
 *
 * proc_handler - the text handler routine (described below)
 *
 * strategy - the strategy routine (described below)
 *
 * de - for internal use by the sysctl routines
 *
 * extra1, extra2 - extra pointers usable by the proc handler routines
 *
 * Leaf nodes in the sysctl tree will be represented by a single file
 * under /proc; non-leaf nodes will be represented by directories.
 *
 * sysctl(2) can automatically manage read and write requests through
 * the sysctl table.  The data and maxlen fields of the ctl_table
 * struct enable minimal validation of the values being written to be
 * performed, and the mode field allows minimal authentication.
 *
 * More sophisticated management can be enabled by the provision of a
 * strategy routine with the table entry.  This will be called before
 * any automatic read or write of the data is performed.
 *
 * The strategy routine may return
 *
 * < 0 - Error occurred (error is passed to user process)
 *
 * 0   - OK - proceed with automatic read or write.
 *
 * > 0 - OK - read or write has been done by the strategy routine, so
 *       return immediately.
 *
 * There must be a proc_handler routine for any terminal nodes
 * mirrored under /proc/sys (non-terminals are handled by a built-in
 * directory handler).  Several default handlers are available to
 * cover common cases -
 *
 * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
 * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(), 
 * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
 *
 * It is the handler's job to read the input buffer from user memory
 * and process it. The handler should return 0 on success.
 *
 * This routine returns %NULL on a failure to register, and a pointer
 * to the table header on success.
 */
struct ctl_table_header *register_sysctl_table(ctl_table * table, 
					       int insert_at_head)
{
	struct ctl_table_header *tmp;
	tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
	if (!tmp)
		return NULL;
	tmp->ctl_table = table;
	INIT_LIST_HEAD(&tmp->ctl_entry);
1449 1450 1451
	tmp->used = 0;
	tmp->unregistering = NULL;
	spin_lock(&sysctl_lock);
Linus Torvalds's avatar
Linus Torvalds committed
1452 1453 1454 1455
	if (insert_at_head)
		list_add(&tmp->ctl_entry, &root_table_header.ctl_entry);
	else
		list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
1456
	spin_unlock(&sysctl_lock);
1457
#ifdef CONFIG_PROC_SYSCTL
1458
	register_proc_table(table, proc_sys_root, tmp);
Linus Torvalds's avatar
Linus Torvalds committed
1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471
#endif
	return tmp;
}

/**
 * unregister_sysctl_table - unregister a sysctl table hierarchy
 * @header: the header returned from register_sysctl_table
 *
 * Unregisters the sysctl table and all children. proc entries may not
 * actually be removed until they are no longer used by anyone.
 */
void unregister_sysctl_table(struct ctl_table_header * header)
{
1472 1473 1474
	might_sleep();
	spin_lock(&sysctl_lock);
	start_unregistering(header);
1475
#ifdef CONFIG_PROC_SYSCTL
Linus Torvalds's avatar
Linus Torvalds committed
1476 1477
	unregister_proc_table(header->ctl_table, proc_sys_root);
#endif
1478
	spin_unlock(&sysctl_lock);
Linus Torvalds's avatar
Linus Torvalds committed
1479 1480 1481
	kfree(header);
}

1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494
#else /* !CONFIG_SYSCTL */
struct ctl_table_header * register_sysctl_table(ctl_table * table,
						int insert_at_head)
{
	return NULL;
}

void unregister_sysctl_table(struct ctl_table_header * table)
{
}

#endif /* CONFIG_SYSCTL */

Linus Torvalds's avatar
Linus Torvalds committed
1495 1496 1497 1498
/*
 * /proc/sys support
 */

1499
#ifdef CONFIG_PROC_SYSCTL
Linus Torvalds's avatar
Linus Torvalds committed
1500 1501

/* Scan the sysctl entries in table and add them all into /proc */
1502
static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
Linus Torvalds's avatar
Linus Torvalds committed
1503 1504 1505 1506 1507
{
	struct proc_dir_entry *de;
	int len;
	mode_t mode;
	
1508
	for (; table->ctl_name || table->procname; table++) {
Linus Torvalds's avatar
Linus Torvalds committed
1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537
		/* Can't do anything without a proc name. */
		if (!table->procname)
			continue;
		/* Maybe we can't do anything with it... */
		if (!table->proc_handler && !table->child) {
			printk(KERN_WARNING "SYSCTL: Can't register %s\n",
				table->procname);
			continue;
		}

		len = strlen(table->procname);
		mode = table->mode;

		de = NULL;
		if (table->proc_handler)
			mode |= S_IFREG;
		else {
			mode |= S_IFDIR;
			for (de = root->subdir; de; de = de->next) {
				if (proc_match(len, table->procname, de))
					break;
			}
			/* If the subdir exists already, de is non-NULL */
		}

		if (!de) {
			de = create_proc_entry(table->procname, mode, root);
			if (!de)
				continue;
1538
			de->set = set;
Linus Torvalds's avatar
Linus Torvalds committed
1539 1540 1541 1542 1543 1544
			de->data = (void *) table;
			if (table->proc_handler)
				de->proc_fops = &proc_sys_file_operations;
		}
		table->de = de;
		if (de->mode & S_IFDIR)
1545
			register_proc_table(table->child, de, set);
Linus Torvalds's avatar
Linus Torvalds committed
1546 1547 1548 1549 1550 1551 1552 1553 1554
	}
}

/*
 * Unregister a /proc sysctl table and any subdirectories.
 */
static void unregister_proc_table(ctl_table * table, struct proc_dir_entry *root)
{
	struct proc_dir_entry *de;