kernel/sysctl.c

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