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