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/capability.h>
  28 #include <linux/ctype.h>
  29 #include <linux/utsname.h>
  30 #include <linux/capability.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/init.h>
  33 #include <linux/kernel.h>
  34 #include <linux/kobject.h>
  35 #include <linux/net.h>
  36 #include <linux/sysrq.h>
  37 #include <linux/highuid.h>
  38 #include <linux/writeback.h>
  39 #include <linux/hugetlb.h>
  40 #include <linux/security.h>
  41 #include <linux/initrd.h>
  42 #include <linux/times.h>
  43 #include <linux/limits.h>
  44 #include <linux/dcache.h>
  45 #include <linux/syscalls.h>
  46 #include <linux/nfs_fs.h>
  47 #include <linux/acpi.h>
  48
  49 #include <asm/uaccess.h>
  50 #include <asm/processor.h>
  51
  52 extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
  53                      void __user *buffer, size_t *lenp, loff_t *ppos);
  54
  55 #ifdef CONFIG_X86
  56 #include <asm/nmi.h>
  57 #include <asm/stacktrace.h>
  58 #endif
  59
  60 #if defined(CONFIG_SYSCTL)
  61
  62 /* External variables not in a header file. */
  63 extern int C_A_D;
  64 extern int sysctl_overcommit_memory;
  65 extern int sysctl_overcommit_ratio;
  66 extern int sysctl_panic_on_oom;
  67 extern int max_threads;
  68 extern int core_uses_pid;
  69 extern int suid_dumpable;
  70 extern char core_pattern[];
  71 extern int pid_max;
  72 extern int min_free_kbytes;
  73 extern int printk_ratelimit_jiffies;
  74 extern int printk_ratelimit_burst;
  75 extern int pid_max_min, pid_max_max;
  76 extern int sysctl_drop_caches;
  77 extern int percpu_pagelist_fraction;
  78 extern int compat_log;
  79 extern int maps_protect;
  80 extern int sysctl_stat_interval;
  81
  82 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
  83 static int maxolduid = 65535;
  84 static int minolduid;
  85 static int min_percpu_pagelist_fract = 8;
  86
  87 static int ngroups_max = NGROUPS_MAX;
  88
  89 #ifdef CONFIG_KMOD
  90 extern char modprobe_path[];
  91 #endif
  92 #ifdef CONFIG_CHR_DEV_SG
  93 extern int sg_big_buff;
  94 #endif
  95
  96 #ifdef __sparc__
  97 extern char reboot_command [];
  98 extern int stop_a_enabled;
  99 extern int scons_pwroff;
 100 #endif
 101
 102 #ifdef __hppa__
 103 extern int pwrsw_enabled;
 104 extern int unaligned_enabled;
 105 #endif
 106
 107 #ifdef CONFIG_S390
 108 #ifdef CONFIG_MATHEMU
 109 extern int sysctl_ieee_emulation_warnings;
 110 #endif
 111 extern int sysctl_userprocess_debug;
 112 extern int spin_retry;
 113 #endif
 114
 115 extern int sysctl_hz_timer;
 116
 117 #ifdef CONFIG_BSD_PROCESS_ACCT
 118 extern int acct_parm[];
 119 #endif
 120
 121 #ifdef CONFIG_IA64
 122 extern int no_unaligned_warning;
 123 #endif
 124
 125 #ifdef CONFIG_RT_MUTEXES
 126 extern int max_lock_depth;
 127 #endif
 128
 129 #ifdef CONFIG_SYSCTL_SYSCALL
 130 static int parse_table(int __user *, int, void __user *, size_t __user *,
 131                 void __user *, size_t, ctl_table *);
 132 #endif
 133
 134
 135 #ifdef CONFIG_PROC_SYSCTL
 136 static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
 137                   void __user *buffer, size_t *lenp, loff_t *ppos);
 138 static int proc_dointvec_taint(ctl_table *table, int write, struct file *filp,
 139                                void __user *buffer, size_t *lenp, loff_t *ppos);
 140 #endif
 141
 142 static ctl_table root_table[];
 143 static struct ctl_table_header root_table_header =
 144         { root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };
 145
 146 static ctl_table kern_table[];
 147 static ctl_table vm_table[];
 148 static ctl_table fs_table[];
 149 static ctl_table debug_table[];
 150 static ctl_table dev_table[];
 151 extern ctl_table random_table[];
 152 #ifdef CONFIG_UNIX98_PTYS
 153 extern ctl_table pty_table[];
 154 #endif
 155 #ifdef CONFIG_INOTIFY_USER
 156 extern ctl_table inotify_table[];
 157 #endif
 158
 159 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 160 int sysctl_legacy_va_layout;
 161 #endif
 162
 163
 164 /* The default sysctl tables: */
 165
 166 static ctl_table root_table[] = {
 167         {
 168                 .ctl_name       = CTL_KERN,
 169                 .procname       = "kernel",
 170                 .mode           = 0555,
 171                 .child          = kern_table,
 172         },
 173         {
 174                 .ctl_name       = CTL_VM,
 175                 .procname       = "vm",
 176                 .mode           = 0555,
 177                 .child          = vm_table,
 178         },
 179 #ifdef CONFIG_NET
 180         {
 181                 .ctl_name       = CTL_NET,
 182                 .procname       = "net",
 183                 .mode           = 0555,
 184                 .child          = net_table,
 185         },
 186 #endif
 187         {
 188                 .ctl_name       = CTL_FS,
 189                 .procname       = "fs",
 190                 .mode           = 0555,
 191                 .child          = fs_table,
 192         },
 193         {
 194                 .ctl_name       = CTL_DEBUG,
 195                 .procname       = "debug",
 196                 .mode           = 0555,
 197                 .child          = debug_table,
 198         },
 199         {
 200                 .ctl_name       = CTL_DEV,
 201                 .procname       = "dev",
 202                 .mode           = 0555,
 203                 .child          = dev_table,
 204         },
 205
 206         { .ctl_name = 0 }
 207 };
 208
 209 static ctl_table kern_table[] = {
 210         {
 211                 .ctl_name       = KERN_PANIC,
 212                 .procname       = "panic",
 213                 .data           = &panic_timeout,
 214                 .maxlen         = sizeof(int),
 215                 .mode           = 0644,
 216                 .proc_handler   = &proc_dointvec,
 217         },
 218         {
 219                 .ctl_name       = KERN_CORE_USES_PID,
 220                 .procname       = "core_uses_pid",
 221                 .data           = &core_uses_pid,
 222                 .maxlen         = sizeof(int),
 223                 .mode           = 0644,
 224                 .proc_handler   = &proc_dointvec,
 225         },
 226         {
 227                 .ctl_name       = KERN_CORE_PATTERN,
 228                 .procname       = "core_pattern",
 229                 .data           = core_pattern,
 230                 .maxlen         = CORENAME_MAX_SIZE,
 231                 .mode           = 0644,
 232                 .proc_handler   = &proc_dostring,
 233                 .strategy       = &sysctl_string,
 234         },
 235 #ifdef CONFIG_PROC_SYSCTL
 236         {
 237                 .ctl_name       = KERN_TAINTED,
 238                 .procname       = "tainted",
 239                 .data           = &tainted,
 240                 .maxlen         = sizeof(int),
 241                 .mode           = 0644,
 242                 .proc_handler   = &proc_dointvec_taint,
 243         },
 244 #endif
 245         {
 246                 .ctl_name       = KERN_CAP_BSET,
 247                 .procname       = "cap-bound",
 248                 .data           = &cap_bset,
 249                 .maxlen         = sizeof(kernel_cap_t),
 250                 .mode           = 0600,
 251                 .proc_handler   = &proc_dointvec_bset,
 252         },
 253 #ifdef CONFIG_BLK_DEV_INITRD
 254         {
 255                 .ctl_name       = KERN_REALROOTDEV,
 256                 .procname       = "real-root-dev",
 257                 .data           = &real_root_dev,
 258                 .maxlen         = sizeof(int),
 259                 .mode           = 0644,
 260                 .proc_handler   = &proc_dointvec,
 261         },
 262 #endif
 263 #ifdef __sparc__
 264         {
 265                 .ctl_name       = KERN_SPARC_REBOOT,
 266                 .procname       = "reboot-cmd",
 267                 .data           = reboot_command,
 268                 .maxlen         = 256,
 269                 .mode           = 0644,
 270                 .proc_handler   = &proc_dostring,
 271                 .strategy       = &sysctl_string,
 272         },
 273         {
 274                 .ctl_name       = KERN_SPARC_STOP_A,
 275                 .procname       = "stop-a",
 276                 .data           = &stop_a_enabled,
 277                 .maxlen         = sizeof (int),
 278                 .mode           = 0644,
 279                 .proc_handler   = &proc_dointvec,
 280         },
 281         {
 282                 .ctl_name       = KERN_SPARC_SCONS_PWROFF,
 283                 .procname       = "scons-poweroff",
 284                 .data           = &scons_pwroff,
 285                 .maxlen         = sizeof (int),
 286                 .mode           = 0644,
 287                 .proc_handler   = &proc_dointvec,
 288         },
 289 #endif
 290 #ifdef __hppa__
 291         {
 292                 .ctl_name       = KERN_HPPA_PWRSW,
 293                 .procname       = "soft-power",
 294                 .data           = &pwrsw_enabled,
 295                 .maxlen         = sizeof (int),
 296                 .mode           = 0644,
 297                 .proc_handler   = &proc_dointvec,
 298         },
 299         {
 300                 .ctl_name       = KERN_HPPA_UNALIGNED,
 301                 .procname       = "unaligned-trap",
 302                 .data           = &unaligned_enabled,
 303                 .maxlen         = sizeof (int),
 304                 .mode           = 0644,
 305                 .proc_handler   = &proc_dointvec,
 306         },
 307 #endif
 308         {
 309                 .ctl_name       = KERN_CTLALTDEL,
 310                 .procname       = "ctrl-alt-del",
 311                 .data           = &C_A_D,
 312                 .maxlen         = sizeof(int),
 313                 .mode           = 0644,
 314                 .proc_handler   = &proc_dointvec,
 315         },
 316         {
 317                 .ctl_name       = KERN_PRINTK,
 318                 .procname       = "printk",
 319                 .data           = &console_loglevel,
 320                 .maxlen         = 4*sizeof(int),
 321                 .mode           = 0644,
 322                 .proc_handler   = &proc_dointvec,
 323         },
 324 #ifdef CONFIG_KMOD
 325         {
 326                 .ctl_name       = KERN_MODPROBE,
 327                 .procname       = "modprobe",
 328                 .data           = &modprobe_path,
 329                 .maxlen         = KMOD_PATH_LEN,
 330                 .mode           = 0644,
 331                 .proc_handler   = &proc_dostring,
 332                 .strategy       = &sysctl_string,
 333         },
 334 #endif
 335 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
 336         {
 337                 .ctl_name       = KERN_HOTPLUG,
 338                 .procname       = "hotplug",
 339                 .data           = &uevent_helper,
 340                 .maxlen         = UEVENT_HELPER_PATH_LEN,
 341                 .mode           = 0644,
 342                 .proc_handler   = &proc_dostring,
 343                 .strategy       = &sysctl_string,
 344         },
 345 #endif
 346 #ifdef CONFIG_CHR_DEV_SG
 347         {
 348                 .ctl_name       = KERN_SG_BIG_BUFF,
 349                 .procname       = "sg-big-buff",
 350                 .data           = &sg_big_buff,
 351                 .maxlen         = sizeof (int),
 352                 .mode           = 0444,
 353                 .proc_handler   = &proc_dointvec,
 354         },
 355 #endif
 356 #ifdef CONFIG_BSD_PROCESS_ACCT
 357         {
 358                 .ctl_name       = KERN_ACCT,
 359                 .procname       = "acct",
 360                 .data           = &acct_parm,
 361                 .maxlen         = 3*sizeof(int),
 362                 .mode           = 0644,
 363                 .proc_handler   = &proc_dointvec,
 364         },
 365 #endif
 366 #ifdef CONFIG_MAGIC_SYSRQ
 367         {
 368                 .ctl_name       = KERN_SYSRQ,
 369                 .procname       = "sysrq",
 370                 .data           = &__sysrq_enabled,
 371                 .maxlen         = sizeof (int),
 372                 .mode           = 0644,
 373                 .proc_handler   = &proc_dointvec,
 374         },
 375 #endif
 376 #ifdef CONFIG_PROC_SYSCTL
 377         {
 378                 .ctl_name       = KERN_CADPID,
 379                 .procname       = "cad_pid",
 380                 .data           = NULL,
 381                 .maxlen         = sizeof (int),
 382                 .mode           = 0600,
 383                 .proc_handler   = &proc_do_cad_pid,
 384         },
 385 #endif
 386         {
 387                 .ctl_name       = KERN_MAX_THREADS,
 388                 .procname       = "threads-max",
 389                 .data           = &max_threads,
 390                 .maxlen         = sizeof(int),
 391                 .mode           = 0644,
 392                 .proc_handler   = &proc_dointvec,
 393         },
 394         {
 395                 .ctl_name       = KERN_RANDOM,
 396                 .procname       = "random",
 397                 .mode           = 0555,
 398                 .child          = random_table,
 399         },
 400 #ifdef CONFIG_UNIX98_PTYS
 401         {
 402                 .ctl_name       = KERN_PTY,
 403                 .procname       = "pty",
 404                 .mode           = 0555,
 405                 .child          = pty_table,
 406         },
 407 #endif
 408         {
 409                 .ctl_name       = KERN_OVERFLOWUID,
 410                 .procname       = "overflowuid",
 411                 .data           = &overflowuid,
 412                 .maxlen         = sizeof(int),
 413                 .mode           = 0644,
 414                 .proc_handler   = &proc_dointvec_minmax,
 415                 .strategy       = &sysctl_intvec,
 416                 .extra1         = &minolduid,
 417                 .extra2         = &maxolduid,
 418         },
 419         {
 420                 .ctl_name       = KERN_OVERFLOWGID,
 421                 .procname       = "overflowgid",
 422                 .data           = &overflowgid,
 423                 .maxlen         = sizeof(int),
 424                 .mode           = 0644,
 425                 .proc_handler   = &proc_dointvec_minmax,
 426                 .strategy       = &sysctl_intvec,
 427                 .extra1         = &minolduid,
 428                 .extra2         = &maxolduid,
 429         },
 430 #ifdef CONFIG_S390
 431 #ifdef CONFIG_MATHEMU
 432         {
 433                 .ctl_name       = KERN_IEEE_EMULATION_WARNINGS,
 434                 .procname       = "ieee_emulation_warnings",
 435                 .data           = &sysctl_ieee_emulation_warnings,
 436                 .maxlen         = sizeof(int),
 437                 .mode           = 0644,
 438                 .proc_handler   = &proc_dointvec,
 439         },
 440 #endif
 441 #ifdef CONFIG_NO_IDLE_HZ
 442         {
 443                 .ctl_name       = KERN_HZ_TIMER,
 444                 .procname       = "hz_timer",
 445                 .data           = &sysctl_hz_timer,
 446                 .maxlen         = sizeof(int),
 447                 .mode           = 0644,
 448                 .proc_handler   = &proc_dointvec,
 449         },
 450 #endif
 451         {
 452                 .ctl_name       = KERN_S390_USER_DEBUG_LOGGING,
 453                 .procname       = "userprocess_debug",
 454                 .data           = &sysctl_userprocess_debug,
 455                 .maxlen         = sizeof(int),
 456                 .mode           = 0644,
 457                 .proc_handler   = &proc_dointvec,
 458         },
 459 #endif
 460         {
 461                 .ctl_name       = KERN_PIDMAX,
 462                 .procname       = "pid_max",
 463                 .data           = &pid_max,
 464                 .maxlen         = sizeof (int),
 465                 .mode           = 0644,
 466                 .proc_handler   = &proc_dointvec_minmax,
 467                 .strategy       = sysctl_intvec,
 468                 .extra1         = &pid_max_min,
 469                 .extra2         = &pid_max_max,
 470         },
 471         {
 472                 .ctl_name       = KERN_PANIC_ON_OOPS,
 473                 .procname       = "panic_on_oops",
 474                 .data           = &panic_on_oops,
 475                 .maxlen         = sizeof(int),
 476                 .mode           = 0644,
 477                 .proc_handler   = &proc_dointvec,
 478         },
 479         {
 480                 .ctl_name       = KERN_PRINTK_RATELIMIT,
 481                 .procname       = "printk_ratelimit",
 482                 .data           = &printk_ratelimit_jiffies,
 483                 .maxlen         = sizeof(int),
 484                 .mode           = 0644,
 485                 .proc_handler   = &proc_dointvec_jiffies,
 486                 .strategy       = &sysctl_jiffies,
 487         },
 488         {
 489                 .ctl_name       = KERN_PRINTK_RATELIMIT_BURST,
 490                 .procname       = "printk_ratelimit_burst",
 491                 .data           = &printk_ratelimit_burst,
 492                 .maxlen         = sizeof(int),
 493                 .mode           = 0644,
 494                 .proc_handler   = &proc_dointvec,
 495         },
 496         {
 497                 .ctl_name       = KERN_NGROUPS_MAX,
 498                 .procname       = "ngroups_max",
 499                 .data           = &ngroups_max,
 500                 .maxlen         = sizeof (int),
 501                 .mode           = 0444,
 502                 .proc_handler   = &proc_dointvec,
 503         },
 504 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 505         {
 506                 .ctl_name       = KERN_UNKNOWN_NMI_PANIC,
 507                 .procname       = "unknown_nmi_panic",
 508                 .data           = &unknown_nmi_panic,
 509                 .maxlen         = sizeof (int),
 510                 .mode           = 0644,
 511                 .proc_handler   = &proc_dointvec,
 512         },
 513         {
 514                 .ctl_name       = KERN_NMI_WATCHDOG,
 515                 .procname       = "nmi_watchdog",
 516                 .data           = &nmi_watchdog_enabled,
 517                 .maxlen         = sizeof (int),
 518                 .mode           = 0644,
 519                 .proc_handler   = &proc_nmi_enabled,
 520         },
 521 #endif
 522 #if defined(CONFIG_X86)
 523         {
 524                 .ctl_name       = KERN_PANIC_ON_NMI,
 525                 .procname       = "panic_on_unrecovered_nmi",
 526                 .data           = &panic_on_unrecovered_nmi,
 527                 .maxlen         = sizeof(int),
 528                 .mode           = 0644,
 529                 .proc_handler   = &proc_dointvec,
 530         },
 531         {
 532                 .ctl_name       = KERN_BOOTLOADER_TYPE,
 533                 .procname       = "bootloader_type",
 534                 .data           = &bootloader_type,
 535                 .maxlen         = sizeof (int),
 536                 .mode           = 0444,
 537                 .proc_handler   = &proc_dointvec,
 538         },
 539         {
 540                 .ctl_name       = CTL_UNNUMBERED,
 541                 .procname       = "kstack_depth_to_print",
 542                 .data           = &kstack_depth_to_print,
 543                 .maxlen         = sizeof(int),
 544                 .mode           = 0644,
 545                 .proc_handler   = &proc_dointvec,
 546         },
 547 #endif
 548 #if defined(CONFIG_MMU)
 549         {
 550                 .ctl_name       = KERN_RANDOMIZE,
 551                 .procname       = "randomize_va_space",
 552                 .data           = &randomize_va_space,
 553                 .maxlen         = sizeof(int),
 554                 .mode           = 0644,
 555                 .proc_handler   = &proc_dointvec,
 556         },
 557 #endif
 558 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
 559         {
 560                 .ctl_name       = KERN_SPIN_RETRY,
 561                 .procname       = "spin_retry",
 562                 .data           = &spin_retry,
 563                 .maxlen         = sizeof (int),
 564                 .mode           = 0644,
 565                 .proc_handler   = &proc_dointvec,
 566         },
 567 #endif
 568 #ifdef CONFIG_ACPI_SLEEP
 569         {
 570                 .ctl_name       = KERN_ACPI_VIDEO_FLAGS,
 571                 .procname       = "acpi_video_flags",
 572                 .data           = &acpi_video_flags,
 573                 .maxlen         = sizeof (unsigned long),
 574                 .mode           = 0644,
 575                 .proc_handler   = &proc_doulongvec_minmax,
 576         },
 577 #endif
 578 #ifdef CONFIG_IA64
 579         {
 580                 .ctl_name       = KERN_IA64_UNALIGNED,
 581                 .procname       = "ignore-unaligned-usertrap",
 582                 .data           = &no_unaligned_warning,
 583                 .maxlen         = sizeof (int),
 584                 .mode           = 0644,
 585                 .proc_handler   = &proc_dointvec,
 586         },
 587 #endif
 588 #ifdef CONFIG_COMPAT
 589         {
 590                 .ctl_name       = KERN_COMPAT_LOG,
 591                 .procname       = "compat-log",
 592                 .data           = &compat_log,
 593                 .maxlen         = sizeof (int),
 594                 .mode           = 0644,
 595                 .proc_handler   = &proc_dointvec,
 596         },
 597 #endif
 598 #ifdef CONFIG_RT_MUTEXES
 599         {
 600                 .ctl_name       = KERN_MAX_LOCK_DEPTH,
 601                 .procname       = "max_lock_depth",
 602                 .data           = &max_lock_depth,
 603                 .maxlen         = sizeof(int),
 604                 .mode           = 0644,
 605                 .proc_handler   = &proc_dointvec,
 606         },
 607 #endif
 608 #ifdef CONFIG_PROC_FS
 609         {
 610                 .ctl_name       = CTL_UNNUMBERED,
 611                 .procname       = "maps_protect",
 612                 .data           = &maps_protect,
 613                 .maxlen         = sizeof(int),
 614                 .mode           = 0644,
 615                 .proc_handler   = &proc_dointvec,
 616         },
 617 #endif
 618
 619         { .ctl_name = 0 }
 620 };
 621
 622 /* Constants for minimum and maximum testing in vm_table.
 623    We use these as one-element integer vectors. */
 624 static int zero;
 625 static int one_hundred = 100;
 626
 627
 628 static ctl_table vm_table[] = {
 629         {
 630                 .ctl_name       = VM_OVERCOMMIT_MEMORY,
 631                 .procname       = "overcommit_memory",
 632                 .data           = &sysctl_overcommit_memory,
 633                 .maxlen         = sizeof(sysctl_overcommit_memory),
 634                 .mode           = 0644,
 635                 .proc_handler   = &proc_dointvec,
 636         },
 637         {
 638                 .ctl_name       = VM_PANIC_ON_OOM,
 639                 .procname       = "panic_on_oom",
 640                 .data           = &sysctl_panic_on_oom,
 641                 .maxlen         = sizeof(sysctl_panic_on_oom),
 642                 .mode           = 0644,
 643                 .proc_handler   = &proc_dointvec,
 644         },
 645         {
 646                 .ctl_name       = VM_OVERCOMMIT_RATIO,
 647                 .procname       = "overcommit_ratio",
 648                 .data           = &sysctl_overcommit_ratio,
 649                 .maxlen         = sizeof(sysctl_overcommit_ratio),
 650                 .mode           = 0644,
 651                 .proc_handler   = &proc_dointvec,
 652         },
 653         {
 654                 .ctl_name       = VM_PAGE_CLUSTER,
 655                 .procname       = "page-cluster",
 656                 .data           = &page_cluster,
 657                 .maxlen         = sizeof(int),
 658                 .mode           = 0644,
 659                 .proc_handler   = &proc_dointvec,
 660         },
 661         {
 662                 .ctl_name       = VM_DIRTY_BACKGROUND,
 663                 .procname       = "dirty_background_ratio",
 664                 .data           = &dirty_background_ratio,
 665                 .maxlen         = sizeof(dirty_background_ratio),
 666                 .mode           = 0644,
 667                 .proc_handler   = &proc_dointvec_minmax,
 668                 .strategy       = &sysctl_intvec,
 669                 .extra1         = &zero,
 670                 .extra2         = &one_hundred,
 671         },
 672         {
 673                 .ctl_name       = VM_DIRTY_RATIO,
 674                 .procname       = "dirty_ratio",
 675                 .data           = &vm_dirty_ratio,
 676                 .maxlen         = sizeof(vm_dirty_ratio),
 677                 .mode           = 0644,
 678                 .proc_handler   = &proc_dointvec_minmax,
 679                 .strategy       = &sysctl_intvec,
 680                 .extra1         = &zero,
 681                 .extra2         = &one_hundred,
 682         },
 683         {
 684                 .ctl_name       = VM_DIRTY_WB_CS,
 685                 .procname       = "dirty_writeback_centisecs",
 686                 .data           = &dirty_writeback_interval,
 687                 .maxlen         = sizeof(dirty_writeback_interval),
 688                 .mode           = 0644,
 689                 .proc_handler   = &dirty_writeback_centisecs_handler,
 690         },
 691         {
 692                 .ctl_name       = VM_DIRTY_EXPIRE_CS,
 693                 .procname       = "dirty_expire_centisecs",
 694                 .data           = &dirty_expire_interval,
 695                 .maxlen         = sizeof(dirty_expire_interval),
 696                 .mode           = 0644,
 697                 .proc_handler   = &proc_dointvec_userhz_jiffies,
 698         },
 699         {
 700                 .ctl_name       = VM_NR_PDFLUSH_THREADS,
 701                 .procname       = "nr_pdflush_threads",
 702                 .data           = &nr_pdflush_threads,
 703                 .maxlen         = sizeof nr_pdflush_threads,
 704                 .mode           = 0444 /* read-only*/,
 705                 .proc_handler   = &proc_dointvec,
 706         },
 707         {
 708                 .ctl_name       = VM_SWAPPINESS,
 709                 .procname       = "swappiness",
 710                 .data           = &vm_swappiness,
 711                 .maxlen         = sizeof(vm_swappiness),
 712                 .mode           = 0644,
 713                 .proc_handler   = &proc_dointvec_minmax,
 714                 .strategy       = &sysctl_intvec,
 715                 .extra1         = &zero,
 716                 .extra2         = &one_hundred,
 717         },
 718 #ifdef CONFIG_HUGETLB_PAGE
 719          {
 720                 .ctl_name       = VM_HUGETLB_PAGES,
 721                 .procname       = "nr_hugepages",
 722                 .data           = &max_huge_pages,
 723                 .maxlen         = sizeof(unsigned long),
 724                 .mode           = 0644,
 725                 .proc_handler   = &hugetlb_sysctl_handler,
 726                 .extra1         = (void *)&hugetlb_zero,
 727                 .extra2         = (void *)&hugetlb_infinity,
 728          },
 729          {
 730                 .ctl_name       = VM_HUGETLB_GROUP,
 731                 .procname       = "hugetlb_shm_group",
 732                 .data           = &sysctl_hugetlb_shm_group,
 733                 .maxlen         = sizeof(gid_t),
 734                 .mode           = 0644,
 735                 .proc_handler   = &proc_dointvec,
 736          },
 737 #endif
 738         {
 739                 .ctl_name       = VM_LOWMEM_RESERVE_RATIO,
 740                 .procname       = "lowmem_reserve_ratio",
 741                 .data           = &sysctl_lowmem_reserve_ratio,
 742                 .maxlen         = sizeof(sysctl_lowmem_reserve_ratio),
 743                 .mode           = 0644,
 744                 .proc_handler   = &lowmem_reserve_ratio_sysctl_handler,
 745                 .strategy       = &sysctl_intvec,
 746         },
 747         {
 748                 .ctl_name       = VM_DROP_PAGECACHE,
 749                 .procname       = "drop_caches",
 750                 .data           = &sysctl_drop_caches,
 751                 .maxlen         = sizeof(int),
 752                 .mode           = 0644,
 753                 .proc_handler   = drop_caches_sysctl_handler,
 754                 .strategy       = &sysctl_intvec,
 755         },
 756         {
 757                 .ctl_name       = VM_MIN_FREE_KBYTES,
 758                 .procname       = "min_free_kbytes",
 759                 .data           = &min_free_kbytes,
 760                 .maxlen         = sizeof(min_free_kbytes),
 761                 .mode           = 0644,
 762                 .proc_handler   = &min_free_kbytes_sysctl_handler,
 763                 .strategy       = &sysctl_intvec,
 764                 .extra1         = &zero,
 765         },
 766         {
 767                 .ctl_name       = VM_PERCPU_PAGELIST_FRACTION,
 768                 .procname       = "percpu_pagelist_fraction",
 769                 .data           = &percpu_pagelist_fraction,
 770                 .maxlen         = sizeof(percpu_pagelist_fraction),
 771                 .mode           = 0644,
 772                 .proc_handler   = &percpu_pagelist_fraction_sysctl_handler,
 773                 .strategy       = &sysctl_intvec,
 774                 .extra1         = &min_percpu_pagelist_fract,
 775         },
 776 #ifdef CONFIG_MMU
 777         {
 778                 .ctl_name       = VM_MAX_MAP_COUNT,
 779                 .procname       = "max_map_count",
 780                 .data           = &sysctl_max_map_count,
 781                 .maxlen         = sizeof(sysctl_max_map_count),
 782                 .mode           = 0644,
 783                 .proc_handler   = &proc_dointvec
 784         },
 785 #endif
 786         {
 787                 .ctl_name       = VM_LAPTOP_MODE,
 788                 .procname       = "laptop_mode",
 789                 .data           = &laptop_mode,
 790                 .maxlen         = sizeof(laptop_mode),
 791                 .mode           = 0644,
 792                 .proc_handler   = &proc_dointvec_jiffies,
 793                 .strategy       = &sysctl_jiffies,
 794         },
 795         {
 796                 .ctl_name       = VM_BLOCK_DUMP,
 797                 .procname       = "block_dump",
 798                 .data           = &block_dump,
 799                 .maxlen         = sizeof(block_dump),
 800                 .mode           = 0644,
 801                 .proc_handler   = &proc_dointvec,
 802                 .strategy       = &sysctl_intvec,
 803                 .extra1         = &zero,
 804         },
 805         {
 806                 .ctl_name       = VM_VFS_CACHE_PRESSURE,
 807                 .procname       = "vfs_cache_pressure",
 808                 .data           = &sysctl_vfs_cache_pressure,
 809                 .maxlen         = sizeof(sysctl_vfs_cache_pressure),
 810                 .mode           = 0644,
 811                 .proc_handler   = &proc_dointvec,
 812                 .strategy       = &sysctl_intvec,
 813                 .extra1         = &zero,
 814         },
 815 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 816         {
 817                 .ctl_name       = VM_LEGACY_VA_LAYOUT,
 818                 .procname       = "legacy_va_layout",
 819                 .data           = &sysctl_legacy_va_layout,
 820                 .maxlen         = sizeof(sysctl_legacy_va_layout),
 821                 .mode           = 0644,
 822                 .proc_handler   = &proc_dointvec,
 823                 .strategy       = &sysctl_intvec,
 824                 .extra1         = &zero,
 825         },
 826 #endif
 827 #ifdef CONFIG_NUMA
 828         {
 829                 .ctl_name       = VM_ZONE_RECLAIM_MODE,
 830                 .procname       = "zone_reclaim_mode",
 831                 .data           = &zone_reclaim_mode,
 832                 .maxlen         = sizeof(zone_reclaim_mode),
 833                 .mode           = 0644,
 834                 .proc_handler   = &proc_dointvec,
 835                 .strategy       = &sysctl_intvec,
 836                 .extra1         = &zero,
 837         },
 838         {
 839                 .ctl_name       = VM_MIN_UNMAPPED,
 840                 .procname       = "min_unmapped_ratio",
 841                 .data           = &sysctl_min_unmapped_ratio,
 842                 .maxlen         = sizeof(sysctl_min_unmapped_ratio),
 843                 .mode           = 0644,
 844                 .proc_handler   = &sysctl_min_unmapped_ratio_sysctl_handler,
 845                 .strategy       = &sysctl_intvec,
 846                 .extra1         = &zero,
 847                 .extra2         = &one_hundred,
 848         },
 849         {
 850                 .ctl_name       = VM_MIN_SLAB,
 851                 .procname       = "min_slab_ratio",
 852                 .data           = &sysctl_min_slab_ratio,
 853                 .maxlen         = sizeof(sysctl_min_slab_ratio),
 854                 .mode           = 0644,
 855                 .proc_handler   = &sysctl_min_slab_ratio_sysctl_handler,
 856                 .strategy       = &sysctl_intvec,
 857                 .extra1         = &zero,
 858                 .extra2         = &one_hundred,
 859         },
 860 #endif
 861 #ifdef CONFIG_SMP
 862         {
 863                 .ctl_name       = CTL_UNNUMBERED,
 864                 .procname       = "stat_interval",
 865                 .data           = &sysctl_stat_interval,
 866                 .maxlen         = sizeof(sysctl_stat_interval),
 867                 .mode           = 0644,
 868                 .proc_handler   = &proc_dointvec_jiffies,
 869                 .strategy       = &sysctl_jiffies,
 870         },
 871 #endif
 872 #if defined(CONFIG_X86_32) || \
 873    (defined(CONFIG_SUPERH) && defined(CONFIG_VSYSCALL))
 874         {
 875                 .ctl_name       = VM_VDSO_ENABLED,
 876                 .procname       = "vdso_enabled",
 877                 .data           = &vdso_enabled,
 878                 .maxlen         = sizeof(vdso_enabled),
 879                 .mode           = 0644,
 880                 .proc_handler   = &proc_dointvec,
 881                 .strategy       = &sysctl_intvec,
 882                 .extra1         = &zero,
 883         },
 884 #endif
 885         { .ctl_name = 0 }
 886 };
 887
 888 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
 889 static ctl_table binfmt_misc_table[] = {
 890         { .ctl_name = 0 }
 891 };
 892 #endif
 893
 894 static ctl_table fs_table[] = {
 895         {
 896                 .ctl_name       = FS_NRINODE,
 897                 .procname       = "inode-nr",
 898                 .data           = &inodes_stat,
 899                 .maxlen         = 2*sizeof(int),
 900                 .mode           = 0444,
 901                 .proc_handler   = &proc_dointvec,
 902         },
 903         {
 904                 .ctl_name       = FS_STATINODE,
 905                 .procname       = "inode-state",
 906                 .data           = &inodes_stat,
 907                 .maxlen         = 7*sizeof(int),
 908                 .mode           = 0444,
 909                 .proc_handler   = &proc_dointvec,
 910         },
 911         {
 912                 .ctl_name       = FS_NRFILE,
 913                 .procname       = "file-nr",
 914                 .data           = &files_stat,
 915                 .maxlen         = 3*sizeof(int),
 916                 .mode           = 0444,
 917                 .proc_handler   = &proc_nr_files,
 918         },
 919         {
 920                 .ctl_name       = FS_MAXFILE,
 921                 .procname       = "file-max",
 922                 .data           = &files_stat.max_files,
 923                 .maxlen         = sizeof(int),
 924                 .mode           = 0644,
 925                 .proc_handler   = &proc_dointvec,
 926         },
 927         {
 928                 .ctl_name       = FS_DENTRY,
 929                 .procname       = "dentry-state",
 930                 .data           = &dentry_stat,
 931                 .maxlen         = 6*sizeof(int),
 932                 .mode           = 0444,
 933                 .proc_handler   = &proc_dointvec,
 934         },
 935         {
 936                 .ctl_name       = FS_OVERFLOWUID,
 937                 .procname       = "overflowuid",
 938                 .data           = &fs_overflowuid,
 939                 .maxlen         = sizeof(int),
 940                 .mode           = 0644,
 941                 .proc_handler   = &proc_dointvec_minmax,
 942                 .strategy       = &sysctl_intvec,
 943                 .extra1         = &minolduid,
 944                 .extra2         = &maxolduid,
 945         },
 946         {
 947                 .ctl_name       = FS_OVERFLOWGID,
 948                 .procname       = "overflowgid",
 949                 .data           = &fs_overflowgid,
 950                 .maxlen         = sizeof(int),
 951                 .mode           = 0644,
 952                 .proc_handler   = &proc_dointvec_minmax,
 953                 .strategy       = &sysctl_intvec,
 954                 .extra1         = &minolduid,
 955                 .extra2         = &maxolduid,
 956         },
 957         {
 958                 .ctl_name       = FS_LEASES,
 959                 .procname       = "leases-enable",
 960                 .data           = &leases_enable,
 961                 .maxlen         = sizeof(int),
 962                 .mode           = 0644,
 963                 .proc_handler   = &proc_dointvec,
 964         },
 965 #ifdef CONFIG_DNOTIFY
 966         {
 967                 .ctl_name       = FS_DIR_NOTIFY,
 968                 .procname       = "dir-notify-enable",
 969                 .data           = &dir_notify_enable,
 970                 .maxlen         = sizeof(int),
 971                 .mode           = 0644,
 972                 .proc_handler   = &proc_dointvec,
 973         },
 974 #endif
 975 #ifdef CONFIG_MMU
 976         {
 977                 .ctl_name       = FS_LEASE_TIME,
 978                 .procname       = "lease-break-time",
 979                 .data           = &lease_break_time,
 980                 .maxlen         = sizeof(int),
 981                 .mode           = 0644,
 982                 .proc_handler   = &proc_dointvec,
 983         },
 984         {
 985                 .ctl_name       = FS_AIO_NR,
 986                 .procname       = "aio-nr",
 987                 .data           = &aio_nr,
 988                 .maxlen         = sizeof(aio_nr),
 989                 .mode           = 0444,
 990                 .proc_handler   = &proc_doulongvec_minmax,
 991         },
 992         {
 993                 .ctl_name       = FS_AIO_MAX_NR,
 994                 .procname       = "aio-max-nr",
 995                 .data           = &aio_max_nr,
 996                 .maxlen         = sizeof(aio_max_nr),
 997                 .mode           = 0644,
 998                 .proc_handler   = &proc_doulongvec_minmax,
 999         },
1000 #ifdef CONFIG_INOTIFY_USER
1001         {
1002                 .ctl_name       = FS_INOTIFY,
1003                 .procname       = "inotify",
1004                 .mode           = 0555,
1005                 .child          = inotify_table,
1006         },
1007 #endif
1008 #endif
1009         {
1010                 .ctl_name       = KERN_SETUID_DUMPABLE,
1011                 .procname       = "suid_dumpable",
1012                 .data           = &suid_dumpable,
1013                 .maxlen         = sizeof(int),
1014                 .mode           = 0644,
1015                 .proc_handler   = &proc_dointvec,
1016         },
1017 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1018         {
1019                 .ctl_name       = CTL_UNNUMBERED,
1020                 .procname       = "binfmt_misc",
1021                 .mode           = 0555,
1022                 .child          = binfmt_misc_table,
1023         },
1024 #endif
1025         { .ctl_name = 0 }
1026 };
1027
1028 static ctl_table debug_table[] = {
1029         { .ctl_name = 0 }
1030 };
1031
1032 static ctl_table dev_table[] = {
1033         { .ctl_name = 0 }
1034 };
1035
1036 static DEFINE_SPINLOCK(sysctl_lock);
1037
1038 /* called under sysctl_lock */
1039 static int use_table(struct ctl_table_header *p)
1040 {
1041         if (unlikely(p->unregistering))
1042                 return 0;
1043         p->used++;
1044         return 1;
1045 }
1046
1047 /* called under sysctl_lock */
1048 static void unuse_table(struct ctl_table_header *p)
1049 {
1050         if (!--p->used)
1051                 if (unlikely(p->unregistering))
1052                         complete(p->unregistering);
1053 }
1054
1055 /* called under sysctl_lock, will reacquire if has to wait */
1056 static void start_unregistering(struct ctl_table_header *p)
1057 {
1058         /*
1059          * if p->used is 0, nobody will ever touch that entry again;
1060          * we'll eliminate all paths to it before dropping sysctl_lock
1061          */
1062         if (unlikely(p->used)) {
1063                 struct completion wait;
1064                 init_completion(&wait);
1065                 p->unregistering = &wait;
1066                 spin_unlock(&sysctl_lock);
1067                 wait_for_completion(&wait);
1068                 spin_lock(&sysctl_lock);
1069         }
1070         /*
1071          * do not remove from the list until nobody holds it; walking the
1072          * list in do_sysctl() relies on that.
1073          */
1074         list_del_init(&p->ctl_entry);
1075 }
1076
1077 void sysctl_head_finish(struct ctl_table_header *head)
1078 {
1079         if (!head)
1080                 return;
1081         spin_lock(&sysctl_lock);
1082         unuse_table(head);
1083         spin_unlock(&sysctl_lock);
1084 }
1085
1086 struct ctl_table_header *sysctl_head_next(struct ctl_table_header *prev)
1087 {
1088         struct ctl_table_header *head;
1089         struct list_head *tmp;
1090         spin_lock(&sysctl_lock);
1091         if (prev) {
1092                 tmp = &prev->ctl_entry;
1093                 unuse_table(prev);
1094                 goto next;
1095         }
1096         tmp = &root_table_header.ctl_entry;
1097         for (;;) {
1098                 head = list_entry(tmp, struct ctl_table_header, ctl_entry);
1099
1100                 if (!use_table(head))
1101                         goto next;
1102                 spin_unlock(&sysctl_lock);
1103                 return head;
1104         next:
1105                 tmp = tmp->next;
1106                 if (tmp == &root_table_header.ctl_entry)
1107                         break;
1108         }
1109         spin_unlock(&sysctl_lock);
1110         return NULL;
1111 }
1112
1113 #ifdef CONFIG_SYSCTL_SYSCALL
1114 int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
1115                void __user *newval, size_t newlen)
1116 {
1117         struct ctl_table_header *head;
1118         int error = -ENOTDIR;
1119
1120         if (nlen <= 0 || nlen >= CTL_MAXNAME)
1121                 return -ENOTDIR;
1122         if (oldval) {
1123                 int old_len;
1124                 if (!oldlenp || get_user(old_len, oldlenp))
1125                         return -EFAULT;
1126         }
1127
1128         for (head = sysctl_head_next(NULL); head;
1129                         head = sysctl_head_next(head)) {
1130                 error = parse_table(name, nlen, oldval, oldlenp,
1131                                         newval, newlen, head->ctl_table);
1132                 if (error != -ENOTDIR) {
1133                         sysctl_head_finish(head);
1134                         break;
1135                 }
1136         }
1137         return error;
1138 }
1139
1140 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
1141 {
1142         struct __sysctl_args tmp;
1143         int error;
1144
1145         if (copy_from_user(&tmp, args, sizeof(tmp)))
1146                 return -EFAULT;
1147
1148         lock_kernel();
1149         error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
1150                           tmp.newval, tmp.newlen);
1151         unlock_kernel();
1152         return error;
1153 }
1154 #endif /* CONFIG_SYSCTL_SYSCALL */
1155
1156 /*
1157  * sysctl_perm does NOT grant the superuser all rights automatically, because
1158  * some sysctl variables are readonly even to root.
1159  */
1160
1161 static int test_perm(int mode, int op)
1162 {
1163         if (!current->euid)
1164                 mode >>= 6;
1165         else if (in_egroup_p(0))
1166                 mode >>= 3;
1167         if ((mode & op & 0007) == op)
1168                 return 0;
1169         return -EACCES;
1170 }
1171
1172 int sysctl_perm(ctl_table *table, int op)
1173 {
1174         int error;
1175         error = security_sysctl(table, op);
1176         if (error)
1177                 return error;
1178         return test_perm(table->mode, op);
1179 }
1180
1181 #ifdef CONFIG_SYSCTL_SYSCALL
1182 static int parse_table(int __user *name, int nlen,
1183                        void __user *oldval, size_t __user *oldlenp,
1184                        void __user *newval, size_t newlen,
1185                        ctl_table *table)
1186 {
1187         int n;
1188 repeat:
1189         if (!nlen)
1190                 return -ENOTDIR;
1191         if (get_user(n, name))
1192                 return -EFAULT;
1193         for ( ; table->ctl_name || table->procname; table++) {
1194                 if (!table->ctl_name)
1195                         continue;
1196                 if (n == table->ctl_name) {
1197                         int error;
1198                         if (table->child) {
1199                                 if (sysctl_perm(table, 001))
1200                                         return -EPERM;
1201                                 name++;
1202                                 nlen--;
1203                                 table = table->child;
1204                                 goto repeat;
1205                         }
1206                         error = do_sysctl_strategy(table, name, nlen,
1207                                                    oldval, oldlenp,
1208                                                    newval, newlen);
1209                         return error;
1210                 }
1211         }
1212         return -ENOTDIR;
1213 }
1214
1215 /* Perform the actual read/write of a sysctl table entry. */
1216 int do_sysctl_strategy (ctl_table *table,
1217                         int __user *name, int nlen,
1218                         void __user *oldval, size_t __user *oldlenp,
1219                         void __user *newval, size_t newlen)
1220 {
1221         int op = 0, rc;
1222         size_t len;
1223
1224         if (oldval)
1225                 op |= 004;
1226         if (newval)
1227                 op |= 002;
1228         if (sysctl_perm(table, op))
1229                 return -EPERM;
1230
1231         if (table->strategy) {
1232                 rc = table->strategy(table, name, nlen, oldval, oldlenp,
1233                                      newval, newlen);
1234                 if (rc < 0)
1235                         return rc;
1236                 if (rc > 0)
1237                         return 0;
1238         }
1239
1240         /* If there is no strategy routine, or if the strategy returns
1241          * zero, proceed with automatic r/w */
1242         if (table->data && table->maxlen) {
1243                 if (oldval && oldlenp) {
1244                         if (get_user(len, oldlenp))
1245                                 return -EFAULT;
1246                         if (len) {
1247                                 if (len > table->maxlen)
1248                                         len = table->maxlen;
1249                                 if(copy_to_user(oldval, table->data, len))
1250                                         return -EFAULT;
1251                                 if(put_user(len, oldlenp))
1252                                         return -EFAULT;
1253                         }
1254                 }
1255                 if (newval && newlen) {
1256                         len = newlen;
1257                         if (len > table->maxlen)
1258                                 len = table->maxlen;
1259                         if(copy_from_user(table->data, newval, len))
1260                                 return -EFAULT;
1261                 }
1262         }
1263         return 0;
1264 }
1265 #endif /* CONFIG_SYSCTL_SYSCALL */
1266
1267 static void sysctl_set_parent(struct ctl_table *parent, struct ctl_table *table)
1268 {
1269         for (; table->ctl_name || table->procname; table++) {
1270                 table->parent = parent;
1271                 if (table->child)
1272                         sysctl_set_parent(table, table->child);
1273         }
1274 }
1275
1276 static __init int sysctl_init(void)
1277 {
1278         sysctl_set_parent(NULL, root_table);
1279         return 0;
1280 }
1281
1282 core_initcall(sysctl_init);
1283
1284 /**
1285  * register_sysctl_table - register a sysctl hierarchy
1286  * @table: the top-level table structure
1287  *
1288  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1289  * array. An entry with a ctl_name of 0 terminates the table.
1290  *
1291  * The members of the &ctl_table structure are used as follows:
1292  *
1293  * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
1294  *            must be unique within that level of sysctl
1295  *
1296  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1297  *            enter a sysctl file
1298  *
1299  * data - a pointer to data for use by proc_handler
1300  *
1301  * maxlen - the maximum size in bytes of the data
1302  *
1303  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1304  *
1305  * child - a pointer to the child sysctl table if this entry is a directory, or
1306  *         %NULL.
1307  *
1308  * proc_handler - the text handler routine (described below)
1309  *
1310  * strategy - the strategy routine (described below)
1311  *
1312  * de - for internal use by the sysctl routines
1313  *
1314  * extra1, extra2 - extra pointers usable by the proc handler routines
1315  *
1316  * Leaf nodes in the sysctl tree will be represented by a single file
1317  * under /proc; non-leaf nodes will be represented by directories.
1318  *
1319  * sysctl(2) can automatically manage read and write requests through
1320  * the sysctl table.  The data and maxlen fields of the ctl_table
1321  * struct enable minimal validation of the values being written to be
1322  * performed, and the mode field allows minimal authentication.
1323  *
1324  * More sophisticated management can be enabled by the provision of a
1325  * strategy routine with the table entry.  This will be called before
1326  * any automatic read or write of the data is performed.
1327  *
1328  * The strategy routine may return
1329  *
1330  * < 0 - Error occurred (error is passed to user process)
1331  *
1332  * 0   - OK - proceed with automatic read or write.
1333  *
1334  * > 0 - OK - read or write has been done by the strategy routine, so
1335  *       return immediately.
1336  *
1337  * There must be a proc_handler routine for any terminal nodes
1338  * mirrored under /proc/sys (non-terminals are handled by a built-in
1339  * directory handler).  Several default handlers are available to
1340  * cover common cases -
1341  *
1342  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1343  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1344  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1345  *
1346  * It is the handler's job to read the input buffer from user memory
1347  * and process it. The handler should return 0 on success.
1348  *
1349  * This routine returns %NULL on a failure to register, and a pointer
1350  * to the table header on success.
1351  */
1352 struct ctl_table_header *register_sysctl_table(ctl_table * table)
1353 {
1354         struct ctl_table_header *tmp;
1355         tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
1356         if (!tmp)
1357                 return NULL;
1358         tmp->ctl_table = table;
1359         INIT_LIST_HEAD(&tmp->ctl_entry);
1360         tmp->used = 0;
1361         tmp->unregistering = NULL;
1362         sysctl_set_parent(NULL, table);
1363         spin_lock(&sysctl_lock);
1364         list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
1365         spin_unlock(&sysctl_lock);
1366         return tmp;
1367 }
1368
1369 /**
1370  * unregister_sysctl_table - unregister a sysctl table hierarchy
1371  * @header: the header returned from register_sysctl_table
1372  *
1373  * Unregisters the sysctl table and all children. proc entries may not
1374  * actually be removed until they are no longer used by anyone.
1375  */
1376 void unregister_sysctl_table(struct ctl_table_header * header)
1377 {
1378         might_sleep();
1379         spin_lock(&sysctl_lock);
1380         start_unregistering(header);
1381         spin_unlock(&sysctl_lock);
1382         kfree(header);
1383 }
1384
1385 #else /* !CONFIG_SYSCTL */
1386 struct ctl_table_header *register_sysctl_table(ctl_table * table)
1387 {
1388         return NULL;
1389 }
1390
1391 void unregister_sysctl_table(struct ctl_table_header * table)
1392 {
1393 }
1394
1395 #endif /* CONFIG_SYSCTL */
1396
1397 /*
1398  * /proc/sys support
1399  */
1400
1401 #ifdef CONFIG_PROC_SYSCTL
1402
1403 static int _proc_do_string(void* data, int maxlen, int write,
1404                            struct file *filp, void __user *buffer,
1405                            size_t *lenp, loff_t *ppos)
1406 {
1407         size_t len;
1408         char __user *p;
1409         char c;
1410
1411         if (!data || !maxlen || !*lenp) {
1412                 *lenp = 0;
1413                 return 0;
1414         }
1415
1416         if (write) {
1417                 len = 0;
1418                 p = buffer;
1419                 while (len < *lenp) {
1420                         if (get_user(c, p++))
1421                                 return -EFAULT;
1422                         if (c == 0 || c == '\n')
1423                                 break;
1424                         len++;
1425                 }
1426                 if (len >= maxlen)
1427                         len = maxlen-1;
1428                 if(copy_from_user(data, buffer, len))
1429                         return -EFAULT;
1430                 ((char *) data)[len] = 0;
1431                 *ppos += *lenp;
1432         } else {
1433                 len = strlen(data);
1434                 if (len > maxlen)
1435                         len = maxlen;
1436
1437                 if (*ppos > len) {
1438                         *lenp = 0;
1439                         return 0;
1440                 }
1441
1442                 data += *ppos;
1443                 len  -= *ppos;
1444
1445                 if (len > *lenp)
1446                         len = *lenp;
1447                 if (len)
1448                         if(copy_to_user(buffer, data, len))
1449                                 return -EFAULT;
1450                 if (len < *lenp) {
1451                         if(put_user('\n', ((char __user *) buffer) + len))
1452                                 return -EFAULT;
1453                         len++;
1454                 }
1455                 *lenp = len;
1456                 *ppos += len;
1457         }
1458         return 0;
1459 }
1460
1461 /**
1462  * proc_dostring - read a string sysctl
1463  * @table: the sysctl table
1464  * @write: %TRUE if this is a write to the sysctl file
1465  * @filp: the file structure
1466  * @buffer: the user buffer
1467  * @lenp: the size of the user buffer
1468  * @ppos: file position
1469  *
1470  * Reads/writes a string from/to the user buffer. If the kernel
1471  * buffer provided is not large enough to hold the string, the
1472  * string is truncated. The copied string is %NULL-terminated.
1473  * If the string is being read by the user process, it is copied
1474  * and a newline '\n' is added. It is truncated if the buffer is
1475  * not large enough.
1476  *
1477  * Returns 0 on success.
1478  */
1479 int proc_dostring(ctl_table *table, int write, struct file *filp,
1480                   void __user *buffer, size_t *lenp, loff_t *ppos)
1481 {
1482         return _proc_do_string(table->data, table->maxlen, write, filp,
1483                                buffer, lenp, ppos);
1484 }
1485
1486
1487 static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
1488                                  int *valp,
1489                                  int write, void *data)
1490 {
1491         if (write) {
1492                 *valp = *negp ? -*lvalp : *lvalp;
1493         } else {
1494                 int val = *valp;
1495                 if (val < 0) {
1496                         *negp = -1;
1497                         *lvalp = (unsigned long)-val;
1498                 } else {
1499                         *negp = 0;
1500                         *lvalp = (unsigned long)val;
1501                 }
1502         }
1503         return 0;
1504 }
1505
1506 static int __do_proc_dointvec(void *tbl_data, ctl_table *table,
1507                   int write, struct file *filp, void __user *buffer,
1508                   size_t *lenp, loff_t *ppos,
1509                   int (*conv)(int *negp, unsigned long *lvalp, int *valp,
1510                               int write, void *data),
1511                   void *data)
1512 {
1513 #define TMPBUFLEN 21
1514         int *i, vleft, first=1, neg, val;
1515         unsigned long lval;
1516         size_t left, len;
1517
1518         char buf[TMPBUFLEN], *p;
1519         char __user *s = buffer;
1520
1521         if (!tbl_data || !table->maxlen || !*lenp ||
1522             (*ppos && !write)) {
1523                 *lenp = 0;
1524                 return 0;
1525         }
1526
1527         i = (int *) tbl_data;
1528         vleft = table->maxlen / sizeof(*i);
1529         left = *lenp;
1530
1531         if (!conv)
1532                 conv = do_proc_dointvec_conv;
1533
1534         for (; left && vleft--; i++, first=0) {
1535                 if (write) {
1536                         while (left) {
1537                                 char c;
1538                                 if (get_user(c, s))
1539                                         return -EFAULT;
1540                                 if (!isspace(c))
1541                                         break;
1542                                 left--;
1543                                 s++;
1544                         }
1545                         if (!left)
1546                                 break;
1547                         neg = 0;
1548                         len = left;
1549                         if (len > sizeof(buf) - 1)
1550                                 len = sizeof(buf) - 1;
1551                         if (copy_from_user(buf, s, len))
1552                                 return -EFAULT;
1553                         buf[len] = 0;
1554                         p = buf;
1555                         if (*p == '-' && left > 1) {
1556                                 neg = 1;
1557                                 p++;
1558                         }
1559                         if (*p < '0' || *p > '9')
1560                                 break;
1561
1562                         lval = simple_strtoul(p, &p, 0);
1563
1564                         len = p-buf;
1565                         if ((len < left) && *p && !isspace(*p))
1566                                 break;
1567                         if (neg)
1568                                 val = -val;
1569                         s += len;
1570                         left -= len;
1571
1572                         if (conv(&neg, &lval, i, 1, data))
1573                                 break;
1574                 } else {
1575                         p = buf;
1576                         if (!first)
1577                                 *p++ = '\t';
1578
1579                         if (conv(&neg, &lval, i, 0, data))
1580                                 break;
1581
1582                         sprintf(p, "%s%lu", neg ? "-" : "", lval);
1583                         len = strlen(buf);
1584                         if (len > left)
1585                                 len = left;
1586                         if(copy_to_user(s, buf, len))
1587                                 return -EFAULT;
1588                         left -= len;
1589                         s += len;
1590                 }
1591         }
1592
1593         if (!write && !first && left) {
1594                 if(put_user('\n', s))
1595                         return -EFAULT;
1596                 left--, s++;
1597         }
1598         if (write) {
1599                 while (left) {
1600                         char c;
1601                         if (get_user(c, s++))
1602                                 return -EFAULT;
1603                         if (!isspace(c))
1604                                 break;
1605                         left--;
1606                 }
1607         }
1608         if (write && first)
1609                 return -EINVAL;
1610         *lenp -= left;
1611         *ppos += *lenp;
1612         return 0;
1613 #undef TMPBUFLEN
1614 }
1615
1616 static int do_proc_dointvec(ctl_table *table, int write, struct file *filp,
1617                   void __user *buffer, size_t *lenp, loff_t *ppos,
1618                   int (*conv)(int *negp, unsigned long *lvalp, int *valp,
1619                               int write, void *data),
1620                   void *data)
1621 {
1622         return __do_proc_dointvec(table->data, table, write, filp,
1623                         buffer, lenp, ppos, conv, data);
1624 }
1625
1626 /**
1627  * proc_dointvec - read a vector of integers
1628  * @table: the sysctl table
1629  * @write: %TRUE if this is a write to the sysctl file
1630  * @filp: the file structure
1631  * @buffer: the user buffer
1632  * @lenp: the size of the user buffer
1633  * @ppos: file position
1634  *
1635  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1636  * values from/to the user buffer, treated as an ASCII string.
1637  *
1638  * Returns 0 on success.
1639  */
1640 int proc_dointvec(ctl_table *table, int write, struct file *filp,
1641                      void __user *buffer, size_t *lenp, loff_t *ppos)
1642 {
1643     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1644                             NULL,NULL);
1645 }
1646
1647 #define OP_SET  0
1648 #define OP_AND  1
1649 #define OP_OR   2
1650
1651 static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp,
1652                                       int *valp,
1653                                       int write, void *data)
1654 {
1655         int op = *(int *)data;
1656         if (write) {
1657                 int val = *negp ? -*lvalp : *lvalp;
1658                 switch(op) {
1659                 case OP_SET:    *valp = val; break;
1660                 case OP_AND:    *valp &= val; break;
1661                 case OP_OR:     *valp |= val; break;
1662                 }
1663         } else {
1664                 int val = *valp;
1665                 if (val < 0) {
1666                         *negp = -1;
1667                         *lvalp = (unsigned long)-val;
1668                 } else {
1669                         *negp = 0;
1670                         *lvalp = (unsigned long)val;
1671                 }
1672         }
1673         return 0;
1674 }
1675
1676 /*
1677  *      init may raise the set.
1678  */
1679
1680 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
1681                         void __user *buffer, size_t *lenp, loff_t *ppos)
1682 {
1683         int op;
1684
1685         if (write && !capable(CAP_SYS_MODULE)) {
1686                 return -EPERM;
1687         }
1688
1689         op = is_init(current) ? OP_SET : OP_AND;
1690         return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1691                                 do_proc_dointvec_bset_conv,&op);
1692 }
1693
1694 /*
1695  *      Taint values can only be increased
1696  */
1697 static int proc_dointvec_taint(ctl_table *table, int write, struct file *filp,
1698                                void __user *buffer, size_t *lenp, loff_t *ppos)
1699 {
1700         int op;
1701
1702         if (write && !capable(CAP_SYS_ADMIN))
1703                 return -EPERM;
1704
1705         op = OP_OR;
1706         return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1707                                 do_proc_dointvec_bset_conv,&op);
1708 }
1709
1710 struct do_proc_dointvec_minmax_conv_param {
1711         int *min;
1712         int *max;
1713 };
1714
1715 static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp,
1716                                         int *valp,
1717                                         int write, void *data)
1718 {
1719         struct do_proc_dointvec_minmax_conv_param *param = data;
1720         if (write) {
1721                 int val = *negp ? -*lvalp : *lvalp;
1722                 if ((param->min && *param->min > val) ||
1723                     (param->max && *param->max < val))
1724                         return -EINVAL;
1725                 *valp = val;
1726         } else {
1727                 int val = *valp;
1728                 if (val < 0) {
1729                         *negp = -1;
1730                         *lvalp = (unsigned long)-val;
1731                 } else {
1732                         *negp = 0;
1733                         *lvalp = (unsigned long)val;
1734                 }
1735         }
1736         return 0;
1737 }
1738
1739 /**
1740  * proc_dointvec_minmax - read a vector of integers with min/max values
1741  * @table: the sysctl table
1742  * @write: %TRUE if this is a write to the sysctl file
1743  * @filp: the file structure
1744  * @buffer: the user buffer
1745  * @lenp: the size of the user buffer
1746  * @ppos: file position
1747  *
1748  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1749  * values from/to the user buffer, treated as an ASCII string.
1750  *
1751  * This routine will ensure the values are within the range specified by
1752  * table->extra1 (min) and table->extra2 (max).
1753  *
1754  * Returns 0 on success.
1755  */
1756 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
1757                   void __user *buffer, size_t *lenp, loff_t *ppos)
1758 {
1759         struct do_proc_dointvec_minmax_conv_param param = {
1760                 .min = (int *) table->extra1,
1761                 .max = (int *) table->extra2,
1762         };
1763         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
1764                                 do_proc_dointvec_minmax_conv, &param);
1765 }
1766
1767 static int __do_proc_doulongvec_minmax(void *data, ctl_table *table, int write,
1768                                      struct file *filp,
1769                                      void __user *buffer,
1770                                      size_t *lenp, loff_t *ppos,
1771                                      unsigned long convmul,
1772                                      unsigned long convdiv)
1773 {
1774 #define TMPBUFLEN 21
1775         unsigned long *i, *min, *max, val;
1776         int vleft, first=1, neg;
1777         size_t len, left;
1778         char buf[TMPBUFLEN], *p;
1779         char __user *s = buffer;
1780
1781         if (!data || !table->maxlen || !*lenp ||
1782             (*ppos && !write)) {
1783                 *lenp = 0;
1784                 return 0;
1785         }
1786
1787         i = (unsigned long *) data;
1788         min = (unsigned long *) table->extra1;
1789         max = (unsigned long *) table->extra2;
1790         vleft = table->maxlen / sizeof(unsigned long);
1791         left = *lenp;
1792
1793         for (; left && vleft--; i++, min++, max++, first=0) {
1794                 if (write) {
1795                         while (left) {
1796                                 char c;
1797                                 if (get_user(c, s))
1798                                         return -EFAULT;
1799                                 if (!isspace(c))
1800                                         break;
1801                                 left--;
1802                                 s++;
1803                         }
1804                         if (!left)
1805                                 break;
1806                         neg = 0;
1807                         len = left;
1808                         if (len > TMPBUFLEN-1)
1809                                 len = TMPBUFLEN-1;
1810                         if (copy_from_user(buf, s, len))
1811                                 return -EFAULT;
1812                         buf[len] = 0;
1813                         p = buf;
1814                         if (*p == '-' && left > 1) {
1815                                 neg = 1;
1816                                 p++;
1817                         }
1818                         if (*p < '0' || *p > '9')
1819                                 break;
1820                         val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
1821                         len = p-buf;
1822                         if ((len < left) && *p && !isspace(*p))
1823                                 break;
1824                         if (neg)
1825                                 val = -val;
1826                         s += len;
1827                         left -= len;
1828
1829                         if(neg)
1830                                 continue;
1831                         if ((min && val < *min) || (max && val > *max))
1832                                 continue;
1833                         *i = val;
1834                 } else {
1835                         p = buf;
1836                         if (!first)
1837                                 *p++ = '\t';
1838                         sprintf(p, "%lu", convdiv * (*i) / convmul);
1839                         len = strlen(buf);
1840                         if (len > left)
1841                                 len = left;
1842                         if(copy_to_user(s, buf, len))
1843                                 return -EFAULT;
1844                         left -= len;
1845                         s += len;
1846                 }
1847         }
1848
1849         if (!write && !first && left) {
1850                 if(put_user('\n', s))
1851                         return -EFAULT;
1852                 left--, s++;
1853         }
1854         if (write) {
1855                 while (left) {
1856                         char c;
1857                         if (get_user(c, s++))
1858                                 return -EFAULT;
1859                         if (!isspace(c))
1860                                 break;
1861                         left--;
1862                 }
1863         }
1864         if (write && first)
1865                 return -EINVAL;
1866         *lenp -= left;
1867         *ppos += *lenp;
1868         return 0;
1869 #undef TMPBUFLEN
1870 }
1871
1872 static int do_proc_doulongvec_minmax(ctl_table *table, int write,
1873                                      struct file *filp,
1874                                      void __user *buffer,
1875                                      size_t *lenp, loff_t *ppos,
1876                                      unsigned long convmul,
1877                                      unsigned long convdiv)
1878 {
1879         return __do_proc_doulongvec_minmax(table->data, table, write,
1880                         filp, buffer, lenp, ppos, convmul, convdiv);
1881 }
1882
1883 /**
1884  * proc_doulongvec_minmax - read a vector of long integers with min/max values
1885  * @table: the sysctl table
1886  * @write: %TRUE if this is a write to the sysctl file
1887  * @filp: the file structure
1888  * @buffer: the user buffer
1889  * @lenp: the size of the user buffer
1890  * @ppos: file position
1891  *
1892  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1893  * values from/to the user buffer, treated as an ASCII string.
1894  *
1895  * This routine will ensure the values are within the range specified by
1896  * table->extra1 (min) and table->extra2 (max).
1897  *
1898  * Returns 0 on success.
1899  */
1900 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
1901                            void __user *buffer, size_t *lenp, loff_t *ppos)
1902 {
1903     return do_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos, 1l, 1l);
1904 }
1905
1906 /**
1907  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
1908  * @table: the sysctl table
1909  * @write: %TRUE if this is a write to the sysctl file
1910  * @filp: the file structure
1911  * @buffer: the user buffer
1912  * @lenp: the size of the user buffer
1913  * @ppos: file position
1914  *
1915  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
1916  * values from/to the user buffer, treated as an ASCII string. The values
1917  * are treated as milliseconds, and converted to jiffies when they are stored.
1918  *
1919  * This routine will ensure the values are within the range specified by
1920  * table->extra1 (min) and table->extra2 (max).
1921  *
1922  * Returns 0 on success.
1923  */
1924 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
1925                                       struct file *filp,
1926                                       void __user *buffer,
1927                                       size_t *lenp, loff_t *ppos)
1928 {
1929     return do_proc_doulongvec_minmax(table, write, filp, buffer,
1930                                      lenp, ppos, HZ, 1000l);
1931 }
1932
1933
1934 static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
1935                                          int *valp,
1936                                          int write, void *data)
1937 {
1938         if (write) {
1939                 if (*lvalp > LONG_MAX / HZ)
1940                         return 1;
1941                 *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
1942         } else {
1943                 int val = *valp;
1944                 unsigned long lval;
1945                 if (val < 0) {
1946                         *negp = -1;
1947                         lval = (unsigned long)-val;
1948                 } else {
1949                         *negp = 0;
1950                         lval = (unsigned long)val;
1951                 }
1952                 *lvalp = lval / HZ;
1953         }
1954         return 0;
1955 }
1956
1957 static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
1958                                                 int *valp,
1959                                                 int write, void *data)
1960 {
1961         if (write) {
1962                 if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
1963                         return 1;
1964                 *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
1965         } else {
1966                 int val = *valp;
1967                 unsigned long lval;
1968                 if (val < 0) {
1969                         *negp = -1;
1970                         lval = (unsigned long)-val;
1971                 } else {
1972                         *negp = 0;
1973                         lval = (unsigned long)val;
1974                 }
1975                 *lvalp = jiffies_to_clock_t(lval);
1976         }
1977         return 0;
1978 }
1979
1980 static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
1981                                             int *valp,
1982                                             int write, void *data)
1983 {
1984         if (write) {
1985                 *valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
1986         } else {
1987                 int val = *valp;
1988                 unsigned long lval;
1989                 if (val < 0) {
1990                         *negp = -1;
1991                         lval = (unsigned long)-val;
1992                 } else {
1993                         *negp = 0;
1994                         lval = (unsigned long)val;
1995                 }
1996                 *lvalp = jiffies_to_msecs(lval);
1997         }
1998         return 0;
1999 }
2000
2001 /**
2002  * proc_dointvec_jiffies - read a vector of integers as seconds
2003  * @table: the sysctl table
2004  * @write: %TRUE if this is a write to the sysctl file
2005  * @filp: the file structure
2006  * @buffer: the user buffer
2007  * @lenp: the size of the user buffer
2008  * @ppos: file position
2009  *
2010  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2011  * values from/to the user buffer, treated as an ASCII string.
2012  * The values read are assumed to be in seconds, and are converted into
2013  * jiffies.
2014  *
2015  * Returns 0 on success.
2016  */
2017 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2018                           void __user *buffer, size_t *lenp, loff_t *ppos)
2019 {
2020     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2021                             do_proc_dointvec_jiffies_conv,NULL);
2022 }
2023
2024 /**
2025  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2026  * @table: the sysctl table
2027  * @write: %TRUE if this is a write to the sysctl file
2028  * @filp: the file structure
2029  * @buffer: the user buffer
2030  * @lenp: the size of the user buffer
2031  * @ppos: pointer to the file position
2032  *
2033  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2034  * values from/to the user buffer, treated as an ASCII string.
2035  * The values read are assumed to be in 1/USER_HZ seconds, and
2036  * are converted into jiffies.
2037  *
2038  * Returns 0 on success.
2039  */
2040 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2041                                  void __user *buffer, size_t *lenp, loff_t *ppos)
2042 {
2043     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2044                             do_proc_dointvec_userhz_jiffies_conv,NULL);
2045 }
2046
2047 /**
2048  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2049  * @table: the sysctl table
2050  * @write: %TRUE if this is a write to the sysctl file
2051  * @filp: the file structure
2052  * @buffer: the user buffer
2053  * @lenp: the size of the user buffer
2054  * @ppos: file position
2055  * @ppos: the current position in the file
2056  *
2057  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2058  * values from/to the user buffer, treated as an ASCII string.
2059  * The values read are assumed to be in 1/1000 seconds, and
2060  * are converted into jiffies.
2061  *
2062  * Returns 0 on success.
2063  */
2064 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2065                              void __user *buffer, size_t *lenp, loff_t *ppos)
2066 {
2067         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
2068                                 do_proc_dointvec_ms_jiffies_conv, NULL);
2069 }
2070
2071 static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
2072                            void __user *buffer, size_t *lenp, loff_t *ppos)
2073 {
2074         struct pid *new_pid;
2075         pid_t tmp;
2076         int r;
2077
2078         tmp = pid_nr(cad_pid);
2079
2080         r = __do_proc_dointvec(&tmp, table, write, filp, buffer,
2081                                lenp, ppos, NULL, NULL);
2082         if (r || !write)
2083                 return r;
2084
2085         new_pid = find_get_pid(tmp);
2086         if (!new_pid)
2087                 return -ESRCH;
2088
2089         put_pid(xchg(&cad_pid, new_pid));
2090         return 0;
2091 }
2092
2093 #else /* CONFIG_PROC_FS */
2094
2095 int proc_dostring(ctl_table *table, int write, struct file *filp,
2096                   void __user *buffer, size_t *lenp, loff_t *ppos)
2097 {
2098         return -ENOSYS;
2099 }
2100
2101 int proc_dointvec(ctl_table *table, int write, struct file *filp,
2102                   void __user *buffer, size_t *lenp, loff_t *ppos)
2103 {
2104         return -ENOSYS;
2105 }
2106
2107 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
2108                         void __user *buffer, size_t *lenp, loff_t *ppos)
2109 {
2110         return -ENOSYS;
2111 }
2112
2113 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
2114                     void __user *buffer, size_t *lenp, loff_t *ppos)
2115 {
2116         return -ENOSYS;
2117 }
2118
2119 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2120                     void __user *buffer, size_t *lenp, loff_t *ppos)
2121 {
2122         return -ENOSYS;
2123 }
2124
2125 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2126                     void __user *buffer, size_t *lenp, loff_t *ppos)
2127 {
2128         return -ENOSYS;
2129 }
2130
2131 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2132                              void __user *buffer, size_t *lenp, loff_t *ppos)
2133 {
2134         return -ENOSYS;
2135 }
2136
2137 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2138                     void __user *buffer, size_t *lenp, loff_t *ppos)
2139 {
2140         return -ENOSYS;
2141 }
2142
2143 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2144                                       struct file *filp,
2145                                       void __user *buffer,
2146                                       size_t *lenp, loff_t *ppos)
2147 {
2148     return -ENOSYS;
2149 }
2150
2151
2152 #endif /* CONFIG_PROC_FS */
2153
2154
2155 #ifdef CONFIG_SYSCTL_SYSCALL
2156 /*
2157  * General sysctl support routines
2158  */
2159
2160 /* The generic string strategy routine: */
2161 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2162                   void __user *oldval, size_t __user *oldlenp,
2163                   void __user *newval, size_t newlen)
2164 {
2165         if (!table->data || !table->maxlen)
2166                 return -ENOTDIR;
2167
2168         if (oldval && oldlenp) {
2169                 size_t bufsize;
2170                 if (get_user(bufsize, oldlenp))
2171                         return -EFAULT;
2172                 if (bufsize) {
2173                         size_t len = strlen(table->data), copied;
2174
2175                         /* This shouldn't trigger for a well-formed sysctl */
2176                         if (len > table->maxlen)
2177                                 len = table->maxlen;
2178
2179                         /* Copy up to a max of bufsize-1 bytes of the string */
2180                         copied = (len >= bufsize) ? bufsize - 1 : len;
2181
2182                         if (copy_to_user(oldval, table->data, copied) ||
2183                             put_user(0, (char __user *)(oldval + copied)))
2184                                 return -EFAULT;
2185                         if (put_user(len, oldlenp))
2186                                 return -EFAULT;
2187                 }
2188         }
2189         if (newval && newlen) {
2190                 size_t len = newlen;
2191                 if (len > table->maxlen)
2192                         len = table->maxlen;
2193                 if(copy_from_user(table->data, newval, len))
2194                         return -EFAULT;
2195                 if (len == table->maxlen)
2196                         len--;
2197                 ((char *) table->data)[len] = 0;
2198         }
2199         return 1;
2200 }
2201
2202 /*
2203  * This function makes sure that all of the integers in the vector
2204  * are between the minimum and maximum values given in the arrays
2205  * table->extra1 and table->extra2, respectively.
2206  */
2207 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2208                 void __user *oldval, size_t __user *oldlenp,
2209                 void __user *newval, size_t newlen)
2210 {
2211
2212         if (newval && newlen) {
2213                 int __user *vec = (int __user *) newval;
2214                 int *min = (int *) table->extra1;
2215                 int *max = (int *) table->extra2;
2216                 size_t length;
2217                 int i;
2218
2219                 if (newlen % sizeof(int) != 0)
2220                         return -EINVAL;
2221
2222                 if (!table->extra1 && !table->extra2)
2223                         return 0;
2224
2225                 if (newlen > table->maxlen)
2226                         newlen = table->maxlen;
2227                 length = newlen / sizeof(int);
2228
2229                 for (i = 0; i < length; i++) {
2230                         int value;
2231                         if (get_user(value, vec + i))
2232                                 return -EFAULT;
2233                         if (min && value < min[i])
2234                                 return -EINVAL;
2235                         if (max && value > max[i])
2236                                 return -EINVAL;
2237                 }
2238         }
2239         return 0;
2240 }
2241
2242 /* Strategy function to convert jiffies to seconds */
2243 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2244                 void __user *oldval, size_t __user *oldlenp,
2245                 void __user *newval, size_t newlen)
2246 {
2247         if (oldval && oldlenp) {
2248                 size_t olen;
2249
2250                 if (get_user(olen, oldlenp))
2251                         return -EFAULT;
2252                 if (olen) {
2253                         int val;
2254
2255                         if (olen < sizeof(int))
2256                                 return -EINVAL;
2257
2258                         val = *(int *)(table->data) / HZ;
2259                         if (put_user(val, (int __user *)oldval))
2260                                 return -EFAULT;
2261                         if (put_user(sizeof(int), oldlenp))
2262                                 return -EFAULT;
2263                 }
2264         }
2265         if (newval && newlen) {
2266                 int new;
2267                 if (newlen != sizeof(int))
2268                         return -EINVAL;
2269                 if (get_user(new, (int __user *)newval))
2270                         return -EFAULT;
2271                 *(int *)(table->data) = new*HZ;
2272         }
2273         return 1;
2274 }
2275
2276 /* Strategy function to convert jiffies to seconds */
2277 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2278                 void __user *oldval, size_t __user *oldlenp,
2279                 void __user *newval, size_t newlen)
2280 {
2281         if (oldval && oldlenp) {
2282                 size_t olen;
2283
2284                 if (get_user(olen, oldlenp))
2285                         return -EFAULT;
2286                 if (olen) {
2287                         int val;
2288
2289                         if (olen < sizeof(int))
2290                                 return -EINVAL;
2291
2292                         val = jiffies_to_msecs(*(int *)(table->data));
2293                         if (put_user(val, (int __user *)oldval))
2294                                 return -EFAULT;
2295                         if (put_user(sizeof(int), oldlenp))
2296                                 return -EFAULT;
2297                 }
2298         }
2299         if (newval && newlen) {
2300                 int new;
2301                 if (newlen != sizeof(int))
2302                         return -EINVAL;
2303                 if (get_user(new, (int __user *)newval))
2304                         return -EFAULT;
2305                 *(int *)(table->data) = msecs_to_jiffies(new);
2306         }
2307         return 1;
2308 }
2309
2310
2311
2312 #else /* CONFIG_SYSCTL_SYSCALL */
2313
2314
2315 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
2316 {
2317         static int msg_count;
2318         struct __sysctl_args tmp;
2319         int name[CTL_MAXNAME];
2320         int i;
2321
2322         /* Read in the sysctl name for better debug message logging */
2323         if (copy_from_user(&tmp, args, sizeof(tmp)))
2324                 return -EFAULT;
2325         if (tmp.nlen <= 0 || tmp.nlen >= CTL_MAXNAME)
2326                 return -ENOTDIR;
2327         for (i = 0; i < tmp.nlen; i++)
2328                 if (get_user(name[i], tmp.name + i))
2329                         return -EFAULT;
2330
2331         /* Ignore accesses to kernel.version */
2332         if ((tmp.nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
2333                 goto out;
2334
2335         if (msg_count < 5) {
2336                 msg_count++;
2337                 printk(KERN_INFO
2338                         "warning: process `%s' used the removed sysctl "
2339                         "system call with ", current->comm);
2340                 for (i = 0; i < tmp.nlen; i++)
2341                         printk("%d.", name[i]);
2342                 printk("\n");
2343         }
2344 out:
2345         return -ENOSYS;
2346 }
2347
2348 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2349                   void __user *oldval, size_t __user *oldlenp,
2350                   void __user *newval, size_t newlen)
2351 {
2352         return -ENOSYS;
2353 }
2354
2355 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2356                 void __user *oldval, size_t __user *oldlenp,
2357                 void __user *newval, size_t newlen)
2358 {
2359         return -ENOSYS;
2360 }
2361
2362 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2363                 void __user *oldval, size_t __user *oldlenp,
2364                 void __user *newval, size_t newlen)
2365 {
2366         return -ENOSYS;
2367 }
2368
2369 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2370                 void __user *oldval, size_t __user *oldlenp,
2371                 void __user *newval, size_t newlen)
2372 {
2373         return -ENOSYS;
2374 }
2375
2376 #endif /* CONFIG_SYSCTL_SYSCALL */
2377
2378 /*
2379  * No sense putting this after each symbol definition, twice,
2380  * exception granted :-)
2381  */
2382 EXPORT_SYMBOL(proc_dointvec);
2383 EXPORT_SYMBOL(proc_dointvec_jiffies);
2384 EXPORT_SYMBOL(proc_dointvec_minmax);
2385 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2386 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2387 EXPORT_SYMBOL(proc_dostring);
2388 EXPORT_SYMBOL(proc_doulongvec_minmax);
2389 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2390 EXPORT_SYMBOL(register_sysctl_table);
2391 EXPORT_SYMBOL(sysctl_intvec);
2392 EXPORT_SYMBOL(sysctl_jiffies);
2393 EXPORT_SYMBOL(sysctl_ms_jiffies);
2394 EXPORT_SYMBOL(sysctl_string);
2395 EXPORT_SYMBOL(unregister_sysctl_table);