kernel/sysctl.c

   1 /*
   2  * sysctl.c: General linux system control interface
   3  *
   4  * Begun 24 March 1995, Stephen Tweedie
   5  * Added /proc support, Dec 1995
   6  * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
   7  * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
   8  * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
   9  * Dynamic registration fixes, Stephen Tweedie.
  10  * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
  11  * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
  12  *  Horn.
  13  * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
  14  * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
  15  * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
  16  *  Wendling.
  17  * The list_for_each() macro wasn't appropriate for the sysctl loop.
  18  *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
  19  */
  20
  21 #include <linux/config.h>
  22 #include <linux/module.h>
  23 #include <linux/mm.h>
  24 #include <linux/swap.h>
  25 #include <linux/slab.h>
  26 #include <linux/sysctl.h>
  27 #include <linux/proc_fs.h>
  28 #include <linux/capability.h>
  29 #include <linux/ctype.h>
  30 #include <linux/utsname.h>
  31 #include <linux/capability.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/init.h>
  34 #include <linux/kernel.h>
  35 #include <linux/kobject.h>
  36 #include <linux/net.h>
  37 #include <linux/sysrq.h>
  38 #include <linux/highuid.h>
  39 #include <linux/writeback.h>
  40 #include <linux/hugetlb.h>
  41 #include <linux/security.h>
  42 #include <linux/initrd.h>
  43 #include <linux/times.h>
  44 #include <linux/limits.h>
  45 #include <linux/dcache.h>
  46 #include <linux/syscalls.h>
  47 #include <linux/nfs_fs.h>
  48 #include <linux/acpi.h>
  49
  50 #include <asm/uaccess.h>
  51 #include <asm/processor.h>
  52
  53 extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
  54                      void __user *buffer, size_t *lenp, loff_t *ppos);
  55
  56 #if defined(CONFIG_SYSCTL)
  57
  58 /* External variables not in a header file. */
  59 extern int C_A_D;
  60 extern int sysctl_overcommit_memory;
  61 extern int sysctl_overcommit_ratio;
  62 extern int sysctl_panic_on_oom;
  63 extern int max_threads;
  64 extern int sysrq_enabled;
  65 extern int core_uses_pid;
  66 extern int suid_dumpable;
  67 extern char core_pattern[];
  68 extern int cad_pid;
  69 extern int pid_max;
  70 extern int min_free_kbytes;
  71 extern int printk_ratelimit_jiffies;
  72 extern int printk_ratelimit_burst;
  73 extern int pid_max_min, pid_max_max;
  74 extern int sysctl_drop_caches;
  75 extern int percpu_pagelist_fraction;
  76
  77 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
  78 int unknown_nmi_panic;
  79 extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *,
  80                                   void __user *, size_t *, loff_t *);
  81 #endif
  82
  83 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
  84 static int maxolduid = 65535;
  85 static int minolduid;
  86 static int min_percpu_pagelist_fract = 8;
  87
  88 static int ngroups_max = NGROUPS_MAX;
  89
  90 #ifdef CONFIG_KMOD
  91 extern char modprobe_path[];
  92 #endif
  93 #ifdef CONFIG_CHR_DEV_SG
  94 extern int sg_big_buff;
  95 #endif
  96 #ifdef CONFIG_SYSVIPC
  97 extern size_t shm_ctlmax;
  98 extern size_t shm_ctlall;
  99 extern int shm_ctlmni;
 100 extern int msg_ctlmax;
 101 extern int msg_ctlmnb;
 102 extern int msg_ctlmni;
 103 extern int sem_ctls[];
 104 #endif
 105
 106 #ifdef __sparc__
 107 extern char reboot_command [];
 108 extern int stop_a_enabled;
 109 extern int scons_pwroff;
 110 #endif
 111
 112 #ifdef __hppa__
 113 extern int pwrsw_enabled;
 114 extern int unaligned_enabled;
 115 #endif
 116
 117 #ifdef CONFIG_S390
 118 #ifdef CONFIG_MATHEMU
 119 extern int sysctl_ieee_emulation_warnings;
 120 #endif
 121 extern int sysctl_userprocess_debug;
 122 extern int spin_retry;
 123 #endif
 124
 125 extern int sysctl_hz_timer;
 126
 127 #ifdef CONFIG_BSD_PROCESS_ACCT
 128 extern int acct_parm[];
 129 #endif
 130
 131 #ifdef CONFIG_IA64
 132 extern int no_unaligned_warning;
 133 #endif
 134
 135 static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
 136                        ctl_table *, void **);
 137 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
 138                   void __user *buffer, size_t *lenp, loff_t *ppos);
 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 /* /proc declarations: */
 162
 163 #ifdef CONFIG_PROC_FS
 164
 165 static ssize_t proc_readsys(struct file *, char __user *, size_t, loff_t *);
 166 static ssize_t proc_writesys(struct file *, const char __user *, size_t, loff_t *);
 167 static int proc_opensys(struct inode *, struct file *);
 168
 169 struct file_operations proc_sys_file_operations = {
 170         .open           = proc_opensys,
 171         .read           = proc_readsys,
 172         .write          = proc_writesys,
 173 };
 174
 175 extern struct proc_dir_entry *proc_sys_root;
 176
 177 static void register_proc_table(ctl_table *, struct proc_dir_entry *, void *);
 178 static void unregister_proc_table(ctl_table *, struct proc_dir_entry *);
 179 #endif
 180
 181 /* The default sysctl tables: */
 182
 183 static ctl_table root_table[] = {
 184         {
 185                 .ctl_name       = CTL_KERN,
 186                 .procname       = "kernel",
 187                 .mode           = 0555,
 188                 .child          = kern_table,
 189         },
 190         {
 191                 .ctl_name       = CTL_VM,
 192                 .procname       = "vm",
 193                 .mode           = 0555,
 194                 .child          = vm_table,
 195         },
 196 #ifdef CONFIG_NET
 197         {
 198                 .ctl_name       = CTL_NET,
 199                 .procname       = "net",
 200                 .mode           = 0555,
 201                 .child          = net_table,
 202         },
 203 #endif
 204         {
 205                 .ctl_name       = CTL_FS,
 206                 .procname       = "fs",
 207                 .mode           = 0555,
 208                 .child          = fs_table,
 209         },
 210         {
 211                 .ctl_name       = CTL_DEBUG,
 212                 .procname       = "debug",
 213                 .mode           = 0555,
 214                 .child          = debug_table,
 215         },
 216         {
 217                 .ctl_name       = CTL_DEV,
 218                 .procname       = "dev",
 219                 .mode           = 0555,
 220                 .child          = dev_table,
 221         },
 222
 223         { .ctl_name = 0 }
 224 };
 225
 226 static ctl_table kern_table[] = {
 227         {
 228                 .ctl_name       = KERN_OSTYPE,
 229                 .procname       = "ostype",
 230                 .data           = system_utsname.sysname,
 231                 .maxlen         = sizeof(system_utsname.sysname),
 232                 .mode           = 0444,
 233                 .proc_handler   = &proc_doutsstring,
 234                 .strategy       = &sysctl_string,
 235         },
 236         {
 237                 .ctl_name       = KERN_OSRELEASE,
 238                 .procname       = "osrelease",
 239                 .data           = system_utsname.release,
 240                 .maxlen         = sizeof(system_utsname.release),
 241                 .mode           = 0444,
 242                 .proc_handler   = &proc_doutsstring,
 243                 .strategy       = &sysctl_string,
 244         },
 245         {
 246                 .ctl_name       = KERN_VERSION,
 247                 .procname       = "version",
 248                 .data           = system_utsname.version,
 249                 .maxlen         = sizeof(system_utsname.version),
 250                 .mode           = 0444,
 251                 .proc_handler   = &proc_doutsstring,
 252                 .strategy       = &sysctl_string,
 253         },
 254         {
 255                 .ctl_name       = KERN_NODENAME,
 256                 .procname       = "hostname",
 257                 .data           = system_utsname.nodename,
 258                 .maxlen         = sizeof(system_utsname.nodename),
 259                 .mode           = 0644,
 260                 .proc_handler   = &proc_doutsstring,
 261                 .strategy       = &sysctl_string,
 262         },
 263         {
 264                 .ctl_name       = KERN_DOMAINNAME,
 265                 .procname       = "domainname",
 266                 .data           = system_utsname.domainname,
 267                 .maxlen         = sizeof(system_utsname.domainname),
 268                 .mode           = 0644,
 269                 .proc_handler   = &proc_doutsstring,
 270                 .strategy       = &sysctl_string,
 271         },
 272         {
 273                 .ctl_name       = KERN_PANIC,
 274                 .procname       = "panic",
 275                 .data           = &panic_timeout,
 276                 .maxlen         = sizeof(int),
 277                 .mode           = 0644,
 278                 .proc_handler   = &proc_dointvec,
 279         },
 280         {
 281                 .ctl_name       = KERN_CORE_USES_PID,
 282                 .procname       = "core_uses_pid",
 283                 .data           = &core_uses_pid,
 284                 .maxlen         = sizeof(int),
 285                 .mode           = 0644,
 286                 .proc_handler   = &proc_dointvec,
 287         },
 288         {
 289                 .ctl_name       = KERN_CORE_PATTERN,
 290                 .procname       = "core_pattern",
 291                 .data           = core_pattern,
 292                 .maxlen         = 64,
 293                 .mode           = 0644,
 294                 .proc_handler   = &proc_dostring,
 295                 .strategy       = &sysctl_string,
 296         },
 297         {
 298                 .ctl_name       = KERN_TAINTED,
 299                 .procname       = "tainted",
 300                 .data           = &tainted,
 301                 .maxlen         = sizeof(int),
 302                 .mode           = 0444,
 303                 .proc_handler   = &proc_dointvec,
 304         },
 305         {
 306                 .ctl_name       = KERN_CAP_BSET,
 307                 .procname       = "cap-bound",
 308                 .data           = &cap_bset,
 309                 .maxlen         = sizeof(kernel_cap_t),
 310                 .mode           = 0600,
 311                 .proc_handler   = &proc_dointvec_bset,
 312         },
 313 #ifdef CONFIG_BLK_DEV_INITRD
 314         {
 315                 .ctl_name       = KERN_REALROOTDEV,
 316                 .procname       = "real-root-dev",
 317                 .data           = &real_root_dev,
 318                 .maxlen         = sizeof(int),
 319                 .mode           = 0644,
 320                 .proc_handler   = &proc_dointvec,
 321         },
 322 #endif
 323 #ifdef __sparc__
 324         {
 325                 .ctl_name       = KERN_SPARC_REBOOT,
 326                 .procname       = "reboot-cmd",
 327                 .data           = reboot_command,
 328                 .maxlen         = 256,
 329                 .mode           = 0644,
 330                 .proc_handler   = &proc_dostring,
 331                 .strategy       = &sysctl_string,
 332         },
 333         {
 334                 .ctl_name       = KERN_SPARC_STOP_A,
 335                 .procname       = "stop-a",
 336                 .data           = &stop_a_enabled,
 337                 .maxlen         = sizeof (int),
 338                 .mode           = 0644,
 339                 .proc_handler   = &proc_dointvec,
 340         },
 341         {
 342                 .ctl_name       = KERN_SPARC_SCONS_PWROFF,
 343                 .procname       = "scons-poweroff",
 344                 .data           = &scons_pwroff,
 345                 .maxlen         = sizeof (int),
 346                 .mode           = 0644,
 347                 .proc_handler   = &proc_dointvec,
 348         },
 349 #endif
 350 #ifdef __hppa__
 351         {
 352                 .ctl_name       = KERN_HPPA_PWRSW,
 353                 .procname       = "soft-power",
 354                 .data           = &pwrsw_enabled,
 355                 .maxlen         = sizeof (int),
 356                 .mode           = 0644,
 357                 .proc_handler   = &proc_dointvec,
 358         },
 359         {
 360                 .ctl_name       = KERN_HPPA_UNALIGNED,
 361                 .procname       = "unaligned-trap",
 362                 .data           = &unaligned_enabled,
 363                 .maxlen         = sizeof (int),
 364                 .mode           = 0644,
 365                 .proc_handler   = &proc_dointvec,
 366         },
 367 #endif
 368         {
 369                 .ctl_name       = KERN_CTLALTDEL,
 370                 .procname       = "ctrl-alt-del",
 371                 .data           = &C_A_D,
 372                 .maxlen         = sizeof(int),
 373                 .mode           = 0644,
 374                 .proc_handler   = &proc_dointvec,
 375         },
 376         {
 377                 .ctl_name       = KERN_PRINTK,
 378                 .procname       = "printk",
 379                 .data           = &console_loglevel,
 380                 .maxlen         = 4*sizeof(int),
 381                 .mode           = 0644,
 382                 .proc_handler   = &proc_dointvec,
 383         },
 384 #ifdef CONFIG_KMOD
 385         {
 386                 .ctl_name       = KERN_MODPROBE,
 387                 .procname       = "modprobe",
 388                 .data           = &modprobe_path,
 389                 .maxlen         = KMOD_PATH_LEN,
 390                 .mode           = 0644,
 391                 .proc_handler   = &proc_dostring,
 392                 .strategy       = &sysctl_string,
 393         },
 394 #endif
 395 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
 396         {
 397                 .ctl_name       = KERN_HOTPLUG,
 398                 .procname       = "hotplug",
 399                 .data           = &uevent_helper,
 400                 .maxlen         = UEVENT_HELPER_PATH_LEN,
 401                 .mode           = 0644,
 402                 .proc_handler   = &proc_dostring,
 403                 .strategy       = &sysctl_string,
 404         },
 405 #endif
 406 #ifdef CONFIG_CHR_DEV_SG
 407         {
 408                 .ctl_name       = KERN_SG_BIG_BUFF,
 409                 .procname       = "sg-big-buff",
 410                 .data           = &sg_big_buff,
 411                 .maxlen         = sizeof (int),
 412                 .mode           = 0444,
 413                 .proc_handler   = &proc_dointvec,
 414         },
 415 #endif
 416 #ifdef CONFIG_BSD_PROCESS_ACCT
 417         {
 418                 .ctl_name       = KERN_ACCT,
 419                 .procname       = "acct",
 420                 .data           = &acct_parm,
 421                 .maxlen         = 3*sizeof(int),
 422                 .mode           = 0644,
 423                 .proc_handler   = &proc_dointvec,
 424         },
 425 #endif
 426 #ifdef CONFIG_SYSVIPC
 427         {
 428                 .ctl_name       = KERN_SHMMAX,
 429                 .procname       = "shmmax",
 430                 .data           = &shm_ctlmax,
 431                 .maxlen         = sizeof (size_t),
 432                 .mode           = 0644,
 433                 .proc_handler   = &proc_doulongvec_minmax,
 434         },
 435         {
 436                 .ctl_name       = KERN_SHMALL,
 437                 .procname       = "shmall",
 438                 .data           = &shm_ctlall,
 439                 .maxlen         = sizeof (size_t),
 440                 .mode           = 0644,
 441                 .proc_handler   = &proc_doulongvec_minmax,
 442         },
 443         {
 444                 .ctl_name       = KERN_SHMMNI,
 445                 .procname       = "shmmni",
 446                 .data           = &shm_ctlmni,
 447                 .maxlen         = sizeof (int),
 448                 .mode           = 0644,
 449                 .proc_handler   = &proc_dointvec,
 450         },
 451         {
 452                 .ctl_name       = KERN_MSGMAX,
 453                 .procname       = "msgmax",
 454                 .data           = &msg_ctlmax,
 455                 .maxlen         = sizeof (int),
 456                 .mode           = 0644,
 457                 .proc_handler   = &proc_dointvec,
 458         },
 459         {
 460                 .ctl_name       = KERN_MSGMNI,
 461                 .procname       = "msgmni",
 462                 .data           = &msg_ctlmni,
 463                 .maxlen         = sizeof (int),
 464                 .mode           = 0644,
 465                 .proc_handler   = &proc_dointvec,
 466         },
 467         {
 468                 .ctl_name       = KERN_MSGMNB,
 469                 .procname       =  "msgmnb",
 470                 .data           = &msg_ctlmnb,
 471                 .maxlen         = sizeof (int),
 472                 .mode           = 0644,
 473                 .proc_handler   = &proc_dointvec,
 474         },
 475         {
 476                 .ctl_name       = KERN_SEM,
 477                 .procname       = "sem",
 478                 .data           = &sem_ctls,
 479                 .maxlen         = 4*sizeof (int),
 480                 .mode           = 0644,
 481                 .proc_handler   = &proc_dointvec,
 482         },
 483 #endif
 484 #ifdef CONFIG_MAGIC_SYSRQ
 485         {
 486                 .ctl_name       = KERN_SYSRQ,
 487                 .procname       = "sysrq",
 488                 .data           = &sysrq_enabled,
 489                 .maxlen         = sizeof (int),
 490                 .mode           = 0644,
 491                 .proc_handler   = &proc_dointvec,
 492         },
 493 #endif
 494         {
 495                 .ctl_name       = KERN_CADPID,
 496                 .procname       = "cad_pid",
 497                 .data           = &cad_pid,
 498                 .maxlen         = sizeof (int),
 499                 .mode           = 0600,
 500                 .proc_handler   = &proc_dointvec,
 501         },
 502         {
 503                 .ctl_name       = KERN_MAX_THREADS,
 504                 .procname       = "threads-max",
 505                 .data           = &max_threads,
 506                 .maxlen         = sizeof(int),
 507                 .mode           = 0644,
 508                 .proc_handler   = &proc_dointvec,
 509         },
 510         {
 511                 .ctl_name       = KERN_RANDOM,
 512                 .procname       = "random",
 513                 .mode           = 0555,
 514                 .child          = random_table,
 515         },
 516 #ifdef CONFIG_UNIX98_PTYS
 517         {
 518                 .ctl_name       = KERN_PTY,
 519                 .procname       = "pty",
 520                 .mode           = 0555,
 521                 .child          = pty_table,
 522         },
 523 #endif
 524         {
 525                 .ctl_name       = KERN_OVERFLOWUID,
 526                 .procname       = "overflowuid",
 527                 .data           = &overflowuid,
 528                 .maxlen         = sizeof(int),
 529                 .mode           = 0644,
 530                 .proc_handler   = &proc_dointvec_minmax,
 531                 .strategy       = &sysctl_intvec,
 532                 .extra1         = &minolduid,
 533                 .extra2         = &maxolduid,
 534         },
 535         {
 536                 .ctl_name       = KERN_OVERFLOWGID,
 537                 .procname       = "overflowgid",
 538                 .data           = &overflowgid,
 539                 .maxlen         = sizeof(int),
 540                 .mode           = 0644,
 541                 .proc_handler   = &proc_dointvec_minmax,
 542                 .strategy       = &sysctl_intvec,
 543                 .extra1         = &minolduid,
 544                 .extra2         = &maxolduid,
 545         },
 546 #ifdef CONFIG_S390
 547 #ifdef CONFIG_MATHEMU
 548         {
 549                 .ctl_name       = KERN_IEEE_EMULATION_WARNINGS,
 550                 .procname       = "ieee_emulation_warnings",
 551                 .data           = &sysctl_ieee_emulation_warnings,
 552                 .maxlen         = sizeof(int),
 553                 .mode           = 0644,
 554                 .proc_handler   = &proc_dointvec,
 555         },
 556 #endif
 557 #ifdef CONFIG_NO_IDLE_HZ
 558         {
 559                 .ctl_name       = KERN_HZ_TIMER,
 560                 .procname       = "hz_timer",
 561                 .data           = &sysctl_hz_timer,
 562                 .maxlen         = sizeof(int),
 563                 .mode           = 0644,
 564                 .proc_handler   = &proc_dointvec,
 565         },
 566 #endif
 567         {
 568                 .ctl_name       = KERN_S390_USER_DEBUG_LOGGING,
 569                 .procname       = "userprocess_debug",
 570                 .data           = &sysctl_userprocess_debug,
 571                 .maxlen         = sizeof(int),
 572                 .mode           = 0644,
 573                 .proc_handler   = &proc_dointvec,
 574         },
 575 #endif
 576         {
 577                 .ctl_name       = KERN_PIDMAX,
 578                 .procname       = "pid_max",
 579                 .data           = &pid_max,
 580                 .maxlen         = sizeof (int),
 581                 .mode           = 0644,
 582                 .proc_handler   = &proc_dointvec_minmax,
 583                 .strategy       = sysctl_intvec,
 584                 .extra1         = &pid_max_min,
 585                 .extra2         = &pid_max_max,
 586         },
 587         {
 588                 .ctl_name       = KERN_PANIC_ON_OOPS,
 589                 .procname       = "panic_on_oops",
 590                 .data           = &panic_on_oops,
 591                 .maxlen         = sizeof(int),
 592                 .mode           = 0644,
 593                 .proc_handler   = &proc_dointvec,
 594         },
 595         {
 596                 .ctl_name       = KERN_PRINTK_RATELIMIT,
 597                 .procname       = "printk_ratelimit",
 598                 .data           = &printk_ratelimit_jiffies,
 599                 .maxlen         = sizeof(int),
 600                 .mode           = 0644,
 601                 .proc_handler   = &proc_dointvec_jiffies,
 602                 .strategy       = &sysctl_jiffies,
 603         },
 604         {
 605                 .ctl_name       = KERN_PRINTK_RATELIMIT_BURST,
 606                 .procname       = "printk_ratelimit_burst",
 607                 .data           = &printk_ratelimit_burst,
 608                 .maxlen         = sizeof(int),
 609                 .mode           = 0644,
 610                 .proc_handler   = &proc_dointvec,
 611         },
 612         {
 613                 .ctl_name       = KERN_NGROUPS_MAX,
 614                 .procname       = "ngroups_max",
 615                 .data           = &ngroups_max,
 616                 .maxlen         = sizeof (int),
 617                 .mode           = 0444,
 618                 .proc_handler   = &proc_dointvec,
 619         },
 620 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 621         {
 622                 .ctl_name       = KERN_UNKNOWN_NMI_PANIC,
 623                 .procname       = "unknown_nmi_panic",
 624                 .data           = &unknown_nmi_panic,
 625                 .maxlen         = sizeof (int),
 626                 .mode           = 0644,
 627                 .proc_handler   = &proc_unknown_nmi_panic,
 628         },
 629 #endif
 630 #if defined(CONFIG_X86)
 631         {
 632                 .ctl_name       = KERN_BOOTLOADER_TYPE,
 633                 .procname       = "bootloader_type",
 634                 .data           = &bootloader_type,
 635                 .maxlen         = sizeof (int),
 636                 .mode           = 0444,
 637                 .proc_handler   = &proc_dointvec,
 638         },
 639 #endif
 640 #if defined(CONFIG_MMU)
 641         {
 642                 .ctl_name       = KERN_RANDOMIZE,
 643                 .procname       = "randomize_va_space",
 644                 .data           = &randomize_va_space,
 645                 .maxlen         = sizeof(int),
 646                 .mode           = 0644,
 647                 .proc_handler   = &proc_dointvec,
 648         },
 649 #endif
 650 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
 651         {
 652                 .ctl_name       = KERN_SPIN_RETRY,
 653                 .procname       = "spin_retry",
 654                 .data           = &spin_retry,
 655                 .maxlen         = sizeof (int),
 656                 .mode           = 0644,
 657                 .proc_handler   = &proc_dointvec,
 658         },
 659 #endif
 660 #ifdef CONFIG_ACPI_SLEEP
 661         {
 662                 .ctl_name       = KERN_ACPI_VIDEO_FLAGS,
 663                 .procname       = "acpi_video_flags",
 664                 .data           = &acpi_video_flags,
 665                 .maxlen         = sizeof (unsigned long),
 666                 .mode           = 0644,
 667                 .proc_handler   = &proc_doulongvec_minmax,
 668         },
 669 #endif
 670 #ifdef CONFIG_IA64
 671         {
 672                 .ctl_name       = KERN_IA64_UNALIGNED,
 673                 .procname       = "ignore-unaligned-usertrap",
 674                 .data           = &no_unaligned_warning,
 675                 .maxlen         = sizeof (int),
 676                 .mode           = 0644,
 677                 .proc_handler   = &proc_dointvec,
 678         },
 679 #endif
 680         { .ctl_name = 0 }
 681 };
 682
 683 /* Constants for minimum and maximum testing in vm_table.
 684    We use these as one-element integer vectors. */
 685 static int zero;
 686 static int one_hundred = 100;
 687
 688
 689 static ctl_table vm_table[] = {
 690         {
 691                 .ctl_name       = VM_OVERCOMMIT_MEMORY,
 692                 .procname       = "overcommit_memory",
 693                 .data           = &sysctl_overcommit_memory,
 694                 .maxlen         = sizeof(sysctl_overcommit_memory),
 695                 .mode           = 0644,
 696                 .proc_handler   = &proc_dointvec,
 697         },
 698         {
 699                 .ctl_name       = VM_PANIC_ON_OOM,
 700                 .procname       = "panic_on_oom",
 701                 .data           = &sysctl_panic_on_oom,
 702                 .maxlen         = sizeof(sysctl_panic_on_oom),
 703                 .mode           = 0644,
 704                 .proc_handler   = &proc_dointvec,
 705         },
 706         {
 707                 .ctl_name       = VM_OVERCOMMIT_RATIO,
 708                 .procname       = "overcommit_ratio",
 709                 .data           = &sysctl_overcommit_ratio,
 710                 .maxlen         = sizeof(sysctl_overcommit_ratio),
 711                 .mode           = 0644,
 712                 .proc_handler   = &proc_dointvec,
 713         },
 714         {
 715                 .ctl_name       = VM_PAGE_CLUSTER,
 716                 .procname       = "page-cluster",
 717                 .data           = &page_cluster,
 718                 .maxlen         = sizeof(int),
 719                 .mode           = 0644,
 720                 .proc_handler   = &proc_dointvec,
 721         },
 722         {
 723                 .ctl_name       = VM_DIRTY_BACKGROUND,
 724                 .procname       = "dirty_background_ratio",
 725                 .data           = &dirty_background_ratio,
 726                 .maxlen         = sizeof(dirty_background_ratio),
 727                 .mode           = 0644,
 728                 .proc_handler   = &proc_dointvec_minmax,
 729                 .strategy       = &sysctl_intvec,
 730                 .extra1         = &zero,
 731                 .extra2         = &one_hundred,
 732         },
 733         {
 734                 .ctl_name       = VM_DIRTY_RATIO,
 735                 .procname       = "dirty_ratio",
 736                 .data           = &vm_dirty_ratio,
 737                 .maxlen         = sizeof(vm_dirty_ratio),
 738                 .mode           = 0644,
 739                 .proc_handler   = &proc_dointvec_minmax,
 740                 .strategy       = &sysctl_intvec,
 741                 .extra1         = &zero,
 742                 .extra2         = &one_hundred,
 743         },
 744         {
 745                 .ctl_name       = VM_DIRTY_WB_CS,
 746                 .procname       = "dirty_writeback_centisecs",
 747                 .data           = &dirty_writeback_interval,
 748                 .maxlen         = sizeof(dirty_writeback_interval),
 749                 .mode           = 0644,
 750                 .proc_handler   = &dirty_writeback_centisecs_handler,
 751         },
 752         {
 753                 .ctl_name       = VM_DIRTY_EXPIRE_CS,
 754                 .procname       = "dirty_expire_centisecs",
 755                 .data           = &dirty_expire_interval,
 756                 .maxlen         = sizeof(dirty_expire_interval),
 757                 .mode           = 0644,
 758                 .proc_handler   = &proc_dointvec_userhz_jiffies,
 759         },
 760         {
 761                 .ctl_name       = VM_NR_PDFLUSH_THREADS,
 762                 .procname       = "nr_pdflush_threads",
 763                 .data           = &nr_pdflush_threads,
 764                 .maxlen         = sizeof nr_pdflush_threads,
 765                 .mode           = 0444 /* read-only*/,
 766                 .proc_handler   = &proc_dointvec,
 767         },
 768         {
 769                 .ctl_name       = VM_SWAPPINESS,
 770                 .procname       = "swappiness",
 771                 .data           = &vm_swappiness,
 772                 .maxlen         = sizeof(vm_swappiness),
 773                 .mode           = 0644,
 774                 .proc_handler   = &proc_dointvec_minmax,
 775                 .strategy       = &sysctl_intvec,
 776                 .extra1         = &zero,
 777                 .extra2         = &one_hundred,
 778         },
 779 #ifdef CONFIG_HUGETLB_PAGE
 780          {
 781                 .ctl_name       = VM_HUGETLB_PAGES,
 782                 .procname       = "nr_hugepages",
 783                 .data           = &max_huge_pages,
 784                 .maxlen         = sizeof(unsigned long),
 785                 .mode           = 0644,
 786                 .proc_handler   = &hugetlb_sysctl_handler,
 787                 .extra1         = (void *)&hugetlb_zero,
 788                 .extra2         = (void *)&hugetlb_infinity,
 789          },
 790          {
 791                 .ctl_name       = VM_HUGETLB_GROUP,
 792                 .procname       = "hugetlb_shm_group",
 793                 .data           = &sysctl_hugetlb_shm_group,
 794                 .maxlen         = sizeof(gid_t),
 795                 .mode           = 0644,
 796                 .proc_handler   = &proc_dointvec,
 797          },
 798 #endif
 799         {
 800                 .ctl_name       = VM_LOWMEM_RESERVE_RATIO,
 801                 .procname       = "lowmem_reserve_ratio",
 802                 .data           = &sysctl_lowmem_reserve_ratio,
 803                 .maxlen         = sizeof(sysctl_lowmem_reserve_ratio),
 804                 .mode           = 0644,
 805                 .proc_handler   = &lowmem_reserve_ratio_sysctl_handler,
 806                 .strategy       = &sysctl_intvec,
 807         },
 808         {
 809                 .ctl_name       = VM_DROP_PAGECACHE,
 810                 .procname       = "drop_caches",
 811                 .data           = &sysctl_drop_caches,
 812                 .maxlen         = sizeof(int),
 813                 .mode           = 0644,
 814                 .proc_handler   = drop_caches_sysctl_handler,
 815                 .strategy       = &sysctl_intvec,
 816         },
 817         {
 818                 .ctl_name       = VM_MIN_FREE_KBYTES,
 819                 .procname       = "min_free_kbytes",
 820                 .data           = &min_free_kbytes,
 821                 .maxlen         = sizeof(min_free_kbytes),
 822                 .mode           = 0644,
 823                 .proc_handler   = &min_free_kbytes_sysctl_handler,
 824                 .strategy       = &sysctl_intvec,
 825                 .extra1         = &zero,
 826         },
 827         {
 828                 .ctl_name       = VM_PERCPU_PAGELIST_FRACTION,
 829                 .procname       = "percpu_pagelist_fraction",
 830                 .data           = &percpu_pagelist_fraction,
 831                 .maxlen         = sizeof(percpu_pagelist_fraction),
 832                 .mode           = 0644,
 833                 .proc_handler   = &percpu_pagelist_fraction_sysctl_handler,
 834                 .strategy       = &sysctl_intvec,
 835                 .extra1         = &min_percpu_pagelist_fract,
 836         },
 837 #ifdef CONFIG_MMU
 838         {
 839                 .ctl_name       = VM_MAX_MAP_COUNT,
 840                 .procname       = "max_map_count",
 841                 .data           = &sysctl_max_map_count,
 842                 .maxlen         = sizeof(sysctl_max_map_count),
 843                 .mode           = 0644,
 844                 .proc_handler   = &proc_dointvec
 845         },
 846 #endif
 847         {
 848                 .ctl_name       = VM_LAPTOP_MODE,
 849                 .procname       = "laptop_mode",
 850                 .data           = &laptop_mode,
 851                 .maxlen         = sizeof(laptop_mode),
 852                 .mode           = 0644,
 853                 .proc_handler   = &proc_dointvec_jiffies,
 854                 .strategy       = &sysctl_jiffies,
 855         },
 856         {
 857                 .ctl_name       = VM_BLOCK_DUMP,
 858                 .procname       = "block_dump",
 859                 .data           = &block_dump,
 860                 .maxlen         = sizeof(block_dump),
 861                 .mode           = 0644,
 862                 .proc_handler   = &proc_dointvec,
 863                 .strategy       = &sysctl_intvec,
 864                 .extra1         = &zero,
 865         },
 866         {
 867                 .ctl_name       = VM_VFS_CACHE_PRESSURE,
 868                 .procname       = "vfs_cache_pressure",
 869                 .data           = &sysctl_vfs_cache_pressure,
 870                 .maxlen         = sizeof(sysctl_vfs_cache_pressure),
 871                 .mode           = 0644,
 872                 .proc_handler   = &proc_dointvec,
 873                 .strategy       = &sysctl_intvec,
 874                 .extra1         = &zero,
 875         },
 876 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 877         {
 878                 .ctl_name       = VM_LEGACY_VA_LAYOUT,
 879                 .procname       = "legacy_va_layout",
 880                 .data           = &sysctl_legacy_va_layout,
 881                 .maxlen         = sizeof(sysctl_legacy_va_layout),
 882                 .mode           = 0644,
 883                 .proc_handler   = &proc_dointvec,
 884                 .strategy       = &sysctl_intvec,
 885                 .extra1         = &zero,
 886         },
 887 #endif
 888 #ifdef CONFIG_SWAP
 889         {
 890                 .ctl_name       = VM_SWAP_TOKEN_TIMEOUT,
 891                 .procname       = "swap_token_timeout",
 892                 .data           = &swap_token_default_timeout,
 893                 .maxlen         = sizeof(swap_token_default_timeout),
 894                 .mode           = 0644,
 895                 .proc_handler   = &proc_dointvec_jiffies,
 896                 .strategy       = &sysctl_jiffies,
 897         },
 898 #endif
 899 #ifdef CONFIG_NUMA
 900         {
 901                 .ctl_name       = VM_ZONE_RECLAIM_MODE,
 902                 .procname       = "zone_reclaim_mode",
 903                 .data           = &zone_reclaim_mode,
 904                 .maxlen         = sizeof(zone_reclaim_mode),
 905                 .mode           = 0644,
 906                 .proc_handler   = &proc_dointvec,
 907                 .strategy       = &sysctl_intvec,
 908                 .extra1         = &zero,
 909         },
 910         {
 911                 .ctl_name       = VM_ZONE_RECLAIM_INTERVAL,
 912                 .procname       = "zone_reclaim_interval",
 913                 .data           = &zone_reclaim_interval,
 914                 .maxlen         = sizeof(zone_reclaim_interval),
 915                 .mode           = 0644,
 916                 .proc_handler   = &proc_dointvec_jiffies,
 917                 .strategy       = &sysctl_jiffies,
 918         },
 919 #endif
 920         { .ctl_name = 0 }
 921 };
 922
 923 static ctl_table fs_table[] = {
 924         {
 925                 .ctl_name       = FS_NRINODE,
 926                 .procname       = "inode-nr",
 927                 .data           = &inodes_stat,
 928                 .maxlen         = 2*sizeof(int),
 929                 .mode           = 0444,
 930                 .proc_handler   = &proc_dointvec,
 931         },
 932         {
 933                 .ctl_name       = FS_STATINODE,
 934                 .procname       = "inode-state",
 935                 .data           = &inodes_stat,
 936                 .maxlen         = 7*sizeof(int),
 937                 .mode           = 0444,
 938                 .proc_handler   = &proc_dointvec,
 939         },
 940         {
 941                 .ctl_name       = FS_NRFILE,
 942                 .procname       = "file-nr",
 943                 .data           = &files_stat,
 944                 .maxlen         = 3*sizeof(int),
 945                 .mode           = 0444,
 946                 .proc_handler   = &proc_nr_files,
 947         },
 948         {
 949                 .ctl_name       = FS_MAXFILE,
 950                 .procname       = "file-max",
 951                 .data           = &files_stat.max_files,
 952                 .maxlen         = sizeof(int),
 953                 .mode           = 0644,
 954                 .proc_handler   = &proc_dointvec,
 955         },
 956         {
 957                 .ctl_name       = FS_DENTRY,
 958                 .procname       = "dentry-state",
 959                 .data           = &dentry_stat,
 960                 .maxlen         = 6*sizeof(int),
 961                 .mode           = 0444,
 962                 .proc_handler   = &proc_dointvec,
 963         },
 964         {
 965                 .ctl_name       = FS_OVERFLOWUID,
 966                 .procname       = "overflowuid",
 967                 .data           = &fs_overflowuid,
 968                 .maxlen         = sizeof(int),
 969                 .mode           = 0644,
 970                 .proc_handler   = &proc_dointvec_minmax,
 971                 .strategy       = &sysctl_intvec,
 972                 .extra1         = &minolduid,
 973                 .extra2         = &maxolduid,
 974         },
 975         {
 976                 .ctl_name       = FS_OVERFLOWGID,
 977                 .procname       = "overflowgid",
 978                 .data           = &fs_overflowgid,
 979                 .maxlen         = sizeof(int),
 980                 .mode           = 0644,
 981                 .proc_handler   = &proc_dointvec_minmax,
 982                 .strategy       = &sysctl_intvec,
 983                 .extra1         = &minolduid,
 984                 .extra2         = &maxolduid,
 985         },
 986         {
 987                 .ctl_name       = FS_LEASES,
 988                 .procname       = "leases-enable",
 989                 .data           = &leases_enable,
 990                 .maxlen         = sizeof(int),
 991                 .mode           = 0644,
 992                 .proc_handler   = &proc_dointvec,
 993         },
 994 #ifdef CONFIG_DNOTIFY
 995         {
 996                 .ctl_name       = FS_DIR_NOTIFY,
 997                 .procname       = "dir-notify-enable",
 998                 .data           = &dir_notify_enable,
 999                 .maxlen         = sizeof(int),
1000                 .mode           = 0644,
1001                 .proc_handler   = &proc_dointvec,
1002         },
1003 #endif
1004 #ifdef CONFIG_MMU
1005         {
1006                 .ctl_name       = FS_LEASE_TIME,
1007                 .procname       = "lease-break-time",
1008                 .data           = &lease_break_time,
1009                 .maxlen         = sizeof(int),
1010                 .mode           = 0644,
1011                 .proc_handler   = &proc_dointvec,
1012         },
1013         {
1014                 .ctl_name       = FS_AIO_NR,
1015                 .procname       = "aio-nr",
1016                 .data           = &aio_nr,
1017                 .maxlen         = sizeof(aio_nr),
1018                 .mode           = 0444,
1019                 .proc_handler   = &proc_doulongvec_minmax,
1020         },
1021         {
1022                 .ctl_name       = FS_AIO_MAX_NR,
1023                 .procname       = "aio-max-nr",
1024                 .data           = &aio_max_nr,
1025                 .maxlen         = sizeof(aio_max_nr),
1026                 .mode           = 0644,
1027                 .proc_handler   = &proc_doulongvec_minmax,
1028         },
1029 #ifdef CONFIG_INOTIFY_USER
1030         {
1031                 .ctl_name       = FS_INOTIFY,
1032                 .procname       = "inotify",
1033                 .mode           = 0555,
1034                 .child          = inotify_table,
1035         },
1036 #endif
1037 #endif
1038         {
1039                 .ctl_name       = KERN_SETUID_DUMPABLE,
1040                 .procname       = "suid_dumpable",
1041                 .data           = &suid_dumpable,
1042                 .maxlen         = sizeof(int),
1043                 .mode           = 0644,
1044                 .proc_handler   = &proc_dointvec,
1045         },
1046         { .ctl_name = 0 }
1047 };
1048
1049 static ctl_table debug_table[] = {
1050         { .ctl_name = 0 }
1051 };
1052
1053 static ctl_table dev_table[] = {
1054         { .ctl_name = 0 }
1055 };
1056
1057 extern void init_irq_proc (void);
1058
1059 static DEFINE_SPINLOCK(sysctl_lock);
1060
1061 /* called under sysctl_lock */
1062 static int use_table(struct ctl_table_header *p)
1063 {
1064         if (unlikely(p->unregistering))
1065                 return 0;
1066         p->used++;
1067         return 1;
1068 }
1069
1070 /* called under sysctl_lock */
1071 static void unuse_table(struct ctl_table_header *p)
1072 {
1073         if (!--p->used)
1074                 if (unlikely(p->unregistering))
1075                         complete(p->unregistering);
1076 }
1077
1078 /* called under sysctl_lock, will reacquire if has to wait */
1079 static void start_unregistering(struct ctl_table_header *p)
1080 {
1081         /*
1082          * if p->used is 0, nobody will ever touch that entry again;
1083          * we'll eliminate all paths to it before dropping sysctl_lock
1084          */
1085         if (unlikely(p->used)) {
1086                 struct completion wait;
1087                 init_completion(&wait);
1088                 p->unregistering = &wait;
1089                 spin_unlock(&sysctl_lock);
1090                 wait_for_completion(&wait);
1091                 spin_lock(&sysctl_lock);
1092         }
1093         /*
1094          * do not remove from the list until nobody holds it; walking the
1095          * list in do_sysctl() relies on that.
1096          */
1097         list_del_init(&p->ctl_entry);
1098 }
1099
1100 void __init sysctl_init(void)
1101 {
1102 #ifdef CONFIG_PROC_FS
1103         register_proc_table(root_table, proc_sys_root, &root_table_header);
1104         init_irq_proc();
1105 #endif
1106 }
1107
1108 int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
1109                void __user *newval, size_t newlen)
1110 {
1111         struct list_head *tmp;
1112         int error = -ENOTDIR;
1113
1114         if (nlen <= 0 || nlen >= CTL_MAXNAME)
1115                 return -ENOTDIR;
1116         if (oldval) {
1117                 int old_len;
1118                 if (!oldlenp || get_user(old_len, oldlenp))
1119                         return -EFAULT;
1120         }
1121         spin_lock(&sysctl_lock);
1122         tmp = &root_table_header.ctl_entry;
1123         do {
1124                 struct ctl_table_header *head =
1125                         list_entry(tmp, struct ctl_table_header, ctl_entry);
1126                 void *context = NULL;
1127
1128                 if (!use_table(head))
1129                         continue;
1130
1131                 spin_unlock(&sysctl_lock);
1132
1133                 error = parse_table(name, nlen, oldval, oldlenp,
1134                                         newval, newlen, head->ctl_table,
1135                                         &context);
1136                 kfree(context);
1137
1138                 spin_lock(&sysctl_lock);
1139                 unuse_table(head);
1140                 if (error != -ENOTDIR)
1141                         break;
1142         } while ((tmp = tmp->next) != &root_table_header.ctl_entry);
1143         spin_unlock(&sysctl_lock);
1144         return error;
1145 }
1146
1147 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
1148 {
1149         struct __sysctl_args tmp;
1150         int error;
1151
1152         if (copy_from_user(&tmp, args, sizeof(tmp)))
1153                 return -EFAULT;
1154
1155         lock_kernel();
1156         error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
1157                           tmp.newval, tmp.newlen);
1158         unlock_kernel();
1159         return error;
1160 }
1161
1162 /*
1163  * ctl_perm does NOT grant the superuser all rights automatically, because
1164  * some sysctl variables are readonly even to root.
1165  */
1166
1167 static int test_perm(int mode, int op)
1168 {
1169         if (!current->euid)
1170                 mode >>= 6;
1171         else if (in_egroup_p(0))
1172                 mode >>= 3;
1173         if ((mode & op & 0007) == op)
1174                 return 0;
1175         return -EACCES;
1176 }
1177
1178 static inline int ctl_perm(ctl_table *table, int op)
1179 {
1180         int error;
1181         error = security_sysctl(table, op);
1182         if (error)
1183                 return error;
1184         return test_perm(table->mode, op);
1185 }
1186
1187 static int parse_table(int __user *name, int nlen,
1188                        void __user *oldval, size_t __user *oldlenp,
1189                        void __user *newval, size_t newlen,
1190                        ctl_table *table, void **context)
1191 {
1192         int n;
1193 repeat:
1194         if (!nlen)
1195                 return -ENOTDIR;
1196         if (get_user(n, name))
1197                 return -EFAULT;
1198         for ( ; table->ctl_name; table++) {
1199                 if (n == table->ctl_name || table->ctl_name == CTL_ANY) {
1200                         int error;
1201                         if (table->child) {
1202                                 if (ctl_perm(table, 001))
1203                                         return -EPERM;
1204                                 if (table->strategy) {
1205                                         error = table->strategy(
1206                                                 table, name, nlen,
1207                                                 oldval, oldlenp,
1208                                                 newval, newlen, context);
1209                                         if (error)
1210                                                 return error;
1211                                 }
1212                                 name++;
1213                                 nlen--;
1214                                 table = table->child;
1215                                 goto repeat;
1216                         }
1217                         error = do_sysctl_strategy(table, name, nlen,
1218                                                    oldval, oldlenp,
1219                                                    newval, newlen, context);
1220                         return error;
1221                 }
1222         }
1223         return -ENOTDIR;
1224 }
1225
1226 /* Perform the actual read/write of a sysctl table entry. */
1227 int do_sysctl_strategy (ctl_table *table,
1228                         int __user *name, int nlen,
1229                         void __user *oldval, size_t __user *oldlenp,
1230                         void __user *newval, size_t newlen, void **context)
1231 {
1232         int op = 0, rc;
1233         size_t len;
1234
1235         if (oldval)
1236                 op |= 004;
1237         if (newval)
1238                 op |= 002;
1239         if (ctl_perm(table, op))
1240                 return -EPERM;
1241
1242         if (table->strategy) {
1243                 rc = table->strategy(table, name, nlen, oldval, oldlenp,
1244                                      newval, newlen, context);
1245                 if (rc < 0)
1246                         return rc;
1247                 if (rc > 0)
1248                         return 0;
1249         }
1250
1251         /* If there is no strategy routine, or if the strategy returns
1252          * zero, proceed with automatic r/w */
1253         if (table->data && table->maxlen) {
1254                 if (oldval && oldlenp) {
1255                         if (get_user(len, oldlenp))
1256                                 return -EFAULT;
1257                         if (len) {
1258                                 if (len > table->maxlen)
1259                                         len = table->maxlen;
1260                                 if(copy_to_user(oldval, table->data, len))
1261                                         return -EFAULT;
1262                                 if(put_user(len, oldlenp))
1263                                         return -EFAULT;
1264                         }
1265                 }
1266                 if (newval && newlen) {
1267                         len = newlen;
1268                         if (len > table->maxlen)
1269                                 len = table->maxlen;
1270                         if(copy_from_user(table->data, newval, len))
1271                                 return -EFAULT;
1272                 }
1273         }
1274         return 0;
1275 }
1276
1277 /**
1278  * register_sysctl_table - register a sysctl hierarchy
1279  * @table: the top-level table structure
1280  * @insert_at_head: whether the entry should be inserted in front or at the end
1281  *
1282  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1283  * array. An entry with a ctl_name of 0 terminates the table.
1284  *
1285  * The members of the &ctl_table structure are used as follows:
1286  *
1287  * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
1288  *            must be unique within that level of sysctl
1289  *
1290  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1291  *            enter a sysctl file
1292  *
1293  * data - a pointer to data for use by proc_handler
1294  *
1295  * maxlen - the maximum size in bytes of the data
1296  *
1297  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1298  *
1299  * child - a pointer to the child sysctl table if this entry is a directory, or
1300  *         %NULL.
1301  *
1302  * proc_handler - the text handler routine (described below)
1303  *
1304  * strategy - the strategy routine (described below)
1305  *
1306  * de - for internal use by the sysctl routines
1307  *
1308  * extra1, extra2 - extra pointers usable by the proc handler routines
1309  *
1310  * Leaf nodes in the sysctl tree will be represented by a single file
1311  * under /proc; non-leaf nodes will be represented by directories.
1312  *
1313  * sysctl(2) can automatically manage read and write requests through
1314  * the sysctl table.  The data and maxlen fields of the ctl_table
1315  * struct enable minimal validation of the values being written to be
1316  * performed, and the mode field allows minimal authentication.
1317  *
1318  * More sophisticated management can be enabled by the provision of a
1319  * strategy routine with the table entry.  This will be called before
1320  * any automatic read or write of the data is performed.
1321  *
1322  * The strategy routine may return
1323  *
1324  * < 0 - Error occurred (error is passed to user process)
1325  *
1326  * 0   - OK - proceed with automatic read or write.
1327  *
1328  * > 0 - OK - read or write has been done by the strategy routine, so
1329  *       return immediately.
1330  *
1331  * There must be a proc_handler routine for any terminal nodes
1332  * mirrored under /proc/sys (non-terminals are handled by a built-in
1333  * directory handler).  Several default handlers are available to
1334  * cover common cases -
1335  *
1336  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1337  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1338  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1339  *
1340  * It is the handler's job to read the input buffer from user memory
1341  * and process it. The handler should return 0 on success.
1342  *
1343  * This routine returns %NULL on a failure to register, and a pointer
1344  * to the table header on success.
1345  */
1346 struct ctl_table_header *register_sysctl_table(ctl_table * table,
1347                                                int insert_at_head)
1348 {
1349         struct ctl_table_header *tmp;
1350         tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
1351         if (!tmp)
1352                 return NULL;
1353         tmp->ctl_table = table;
1354         INIT_LIST_HEAD(&tmp->ctl_entry);
1355         tmp->used = 0;
1356         tmp->unregistering = NULL;
1357         spin_lock(&sysctl_lock);
1358         if (insert_at_head)
1359                 list_add(&tmp->ctl_entry, &root_table_header.ctl_entry);
1360         else
1361                 list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
1362         spin_unlock(&sysctl_lock);
1363 #ifdef CONFIG_PROC_FS
1364         register_proc_table(table, proc_sys_root, tmp);
1365 #endif
1366         return tmp;
1367 }
1368
1369 /**
1370  * unregister_sysctl_table - unregister a sysctl table hierarchy
1371  * @header: the header returned from register_sysctl_table
1372  *
1373  * Unregisters the sysctl table and all children. proc entries may not
1374  * actually be removed until they are no longer used by anyone.
1375  */
1376 void unregister_sysctl_table(struct ctl_table_header * header)
1377 {
1378         might_sleep();
1379         spin_lock(&sysctl_lock);
1380         start_unregistering(header);
1381 #ifdef CONFIG_PROC_FS
1382         unregister_proc_table(header->ctl_table, proc_sys_root);
1383 #endif
1384         spin_unlock(&sysctl_lock);
1385         kfree(header);
1386 }
1387
1388 /*
1389  * /proc/sys support
1390  */
1391
1392 #ifdef CONFIG_PROC_FS
1393
1394 /* Scan the sysctl entries in table and add them all into /proc */
1395 static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
1396 {
1397         struct proc_dir_entry *de;
1398         int len;
1399         mode_t mode;
1400
1401         for (; table->ctl_name; table++) {
1402                 /* Can't do anything without a proc name. */
1403                 if (!table->procname)
1404                         continue;
1405                 /* Maybe we can't do anything with it... */
1406                 if (!table->proc_handler && !table->child) {
1407                         printk(KERN_WARNING "SYSCTL: Can't register %s\n",
1408                                 table->procname);
1409                         continue;
1410                 }
1411
1412                 len = strlen(table->procname);
1413                 mode = table->mode;
1414
1415                 de = NULL;
1416                 if (table->proc_handler)
1417                         mode |= S_IFREG;
1418                 else {
1419                         mode |= S_IFDIR;
1420                         for (de = root->subdir; de; de = de->next) {
1421                                 if (proc_match(len, table->procname, de))
1422                                         break;
1423                         }
1424                         /* If the subdir exists already, de is non-NULL */
1425                 }
1426
1427                 if (!de) {
1428                         de = create_proc_entry(table->procname, mode, root);
1429                         if (!de)
1430                                 continue;
1431                         de->set = set;
1432                         de->data = (void *) table;
1433                         if (table->proc_handler)
1434                                 de->proc_fops = &proc_sys_file_operations;
1435                 }
1436                 table->de = de;
1437                 if (de->mode & S_IFDIR)
1438                         register_proc_table(table->child, de, set);
1439         }
1440 }
1441
1442 /*
1443  * Unregister a /proc sysctl table and any subdirectories.
1444  */
1445 static void unregister_proc_table(ctl_table * table, struct proc_dir_entry *root)
1446 {
1447         struct proc_dir_entry *de;
1448         for (; table->ctl_name; table++) {
1449                 if (!(de = table->de))
1450                         continue;
1451                 if (de->mode & S_IFDIR) {
1452                         if (!table->child) {
1453                                 printk (KERN_ALERT "Help - malformed sysctl tree on free\n");
1454                                 continue;
1455                         }
1456                         unregister_proc_table(table->child, de);
1457
1458                         /* Don't unregister directories which still have entries.. */
1459                         if (de->subdir)
1460                                 continue;
1461                 }
1462
1463                 /*
1464                  * In any case, mark the entry as goner; we'll keep it
1465                  * around if it's busy, but we'll know to do nothing with
1466                  * its fields.  We are under sysctl_lock here.
1467                  */
1468                 de->data = NULL;
1469
1470                 /* Don't unregister proc entries that are still being used.. */
1471                 if (atomic_read(&de->count))
1472                         continue;
1473
1474                 table->de = NULL;
1475                 remove_proc_entry(table->procname, root);
1476         }
1477 }
1478
1479 static ssize_t do_rw_proc(int write, struct file * file, char __user * buf,
1480                           size_t count, loff_t *ppos)
1481 {
1482         int op;
1483         struct proc_dir_entry *de = PDE(file->f_dentry->d_inode);
1484         struct ctl_table *table;
1485         size_t res;
1486         ssize_t error = -ENOTDIR;
1487
1488         spin_lock(&sysctl_lock);
1489         if (de && de->data && use_table(de->set)) {
1490                 /*
1491                  * at that point we know that sysctl was not unregistered
1492                  * and won't be until we finish
1493                  */
1494                 spin_unlock(&sysctl_lock);
1495                 table = (struct ctl_table *) de->data;
1496                 if (!table || !table->proc_handler)
1497                         goto out;
1498                 error = -EPERM;
1499                 op = (write ? 002 : 004);
1500                 if (ctl_perm(table, op))
1501                         goto out;
1502
1503                 /* careful: calling conventions are nasty here */
1504                 res = count;
1505                 error = (*table->proc_handler)(table, write, file,
1506                                                 buf, &res, ppos);
1507                 if (!error)
1508                         error = res;
1509         out:
1510                 spin_lock(&sysctl_lock);
1511                 unuse_table(de->set);
1512         }
1513         spin_unlock(&sysctl_lock);
1514         return error;
1515 }
1516
1517 static int proc_opensys(struct inode *inode, struct file *file)
1518 {
1519         if (file->f_mode & FMODE_WRITE) {
1520                 /*
1521                  * sysctl entries that are not writable,
1522                  * are _NOT_ writable, capabilities or not.
1523                  */
1524                 if (!(inode->i_mode & S_IWUSR))
1525                         return -EPERM;
1526         }
1527
1528         return 0;
1529 }
1530
1531 static ssize_t proc_readsys(struct file * file, char __user * buf,
1532                             size_t count, loff_t *ppos)
1533 {
1534         return do_rw_proc(0, file, buf, count, ppos);
1535 }
1536
1537 static ssize_t proc_writesys(struct file * file, const char __user * buf,
1538                              size_t count, loff_t *ppos)
1539 {
1540         return do_rw_proc(1, file, (char __user *) buf, count, ppos);
1541 }
1542
1543 /**
1544  * proc_dostring - read a string sysctl
1545  * @table: the sysctl table
1546  * @write: %TRUE if this is a write to the sysctl file
1547  * @filp: the file structure
1548  * @buffer: the user buffer
1549  * @lenp: the size of the user buffer
1550  * @ppos: file position
1551  *
1552  * Reads/writes a string from/to the user buffer. If the kernel
1553  * buffer provided is not large enough to hold the string, the
1554  * string is truncated. The copied string is %NULL-terminated.
1555  * If the string is being read by the user process, it is copied
1556  * and a newline '\n' is added. It is truncated if the buffer is
1557  * not large enough.
1558  *
1559  * Returns 0 on success.
1560  */
1561 int proc_dostring(ctl_table *table, int write, struct file *filp,
1562                   void __user *buffer, size_t *lenp, loff_t *ppos)
1563 {
1564         size_t len;
1565         char __user *p;
1566         char c;
1567
1568         if (!table->data || !table->maxlen || !*lenp ||
1569             (*ppos && !write)) {
1570                 *lenp = 0;
1571                 return 0;
1572         }
1573
1574         if (write) {
1575                 len = 0;
1576                 p = buffer;
1577                 while (len < *lenp) {
1578                         if (get_user(c, p++))
1579                                 return -EFAULT;
1580                         if (c == 0 || c == '\n')
1581                                 break;
1582                         len++;
1583                 }
1584                 if (len >= table->maxlen)
1585                         len = table->maxlen-1;
1586                 if(copy_from_user(table->data, buffer, len))
1587                         return -EFAULT;
1588                 ((char *) table->data)[len] = 0;
1589                 *ppos += *lenp;
1590         } else {
1591                 len = strlen(table->data);
1592                 if (len > table->maxlen)
1593                         len = table->maxlen;
1594                 if (len > *lenp)
1595                         len = *lenp;
1596                 if (len)
1597                         if(copy_to_user(buffer, table->data, len))
1598                                 return -EFAULT;
1599                 if (len < *lenp) {
1600                         if(put_user('\n', ((char __user *) buffer) + len))
1601                                 return -EFAULT;
1602                         len++;
1603                 }
1604                 *lenp = len;
1605                 *ppos += len;
1606         }
1607         return 0;
1608 }
1609
1610 /*
1611  *      Special case of dostring for the UTS structure. This has locks
1612  *      to observe. Should this be in kernel/sys.c ????
1613  */
1614
1615 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
1616                   void __user *buffer, size_t *lenp, loff_t *ppos)
1617 {
1618         int r;
1619
1620         if (!write) {
1621                 down_read(&uts_sem);
1622                 r=proc_dostring(table,0,filp,buffer,lenp, ppos);
1623                 up_read(&uts_sem);
1624         } else {
1625                 down_write(&uts_sem);
1626                 r=proc_dostring(table,1,filp,buffer,lenp, ppos);
1627                 up_write(&uts_sem);
1628         }
1629         return r;
1630 }
1631
1632 static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
1633                                  int *valp,
1634                                  int write, void *data)
1635 {
1636         if (write) {
1637                 *valp = *negp ? -*lvalp : *lvalp;
1638         } else {
1639                 int val = *valp;
1640                 if (val < 0) {
1641                         *negp = -1;
1642                         *lvalp = (unsigned long)-val;
1643                 } else {
1644                         *negp = 0;
1645                         *lvalp = (unsigned long)val;
1646                 }
1647         }
1648         return 0;
1649 }
1650
1651 static int do_proc_dointvec(ctl_table *table, int write, struct file *filp,
1652                   void __user *buffer, size_t *lenp, loff_t *ppos,
1653                   int (*conv)(int *negp, unsigned long *lvalp, int *valp,
1654                               int write, void *data),
1655                   void *data)
1656 {
1657 #define TMPBUFLEN 21
1658         int *i, vleft, first=1, neg, val;
1659         unsigned long lval;
1660         size_t left, len;
1661
1662         char buf[TMPBUFLEN], *p;
1663         char __user *s = buffer;
1664
1665         if (!table->data || !table->maxlen || !*lenp ||
1666             (*ppos && !write)) {
1667                 *lenp = 0;
1668                 return 0;
1669         }
1670
1671         i = (int *) table->data;
1672         vleft = table->maxlen / sizeof(*i);
1673         left = *lenp;
1674
1675         if (!conv)
1676                 conv = do_proc_dointvec_conv;
1677
1678         for (; left && vleft--; i++, first=0) {
1679                 if (write) {
1680                         while (left) {
1681                                 char c;
1682                                 if (get_user(c, s))
1683                                         return -EFAULT;
1684                                 if (!isspace(c))
1685                                         break;
1686                                 left--;
1687                                 s++;
1688                         }
1689                         if (!left)
1690                                 break;
1691                         neg = 0;
1692                         len = left;
1693                         if (len > sizeof(buf) - 1)
1694                                 len = sizeof(buf) - 1;
1695                         if (copy_from_user(buf, s, len))
1696                                 return -EFAULT;
1697                         buf[len] = 0;
1698                         p = buf;
1699                         if (*p == '-' && left > 1) {
1700                                 neg = 1;
1701                                 left--, p++;
1702                         }
1703                         if (*p < '0' || *p > '9')
1704                                 break;
1705
1706                         lval = simple_strtoul(p, &p, 0);
1707
1708                         len = p-buf;
1709                         if ((len < left) && *p && !isspace(*p))
1710                                 break;
1711                         if (neg)
1712                                 val = -val;
1713                         s += len;
1714                         left -= len;
1715
1716                         if (conv(&neg, &lval, i, 1, data))
1717                                 break;
1718                 } else {
1719                         p = buf;
1720                         if (!first)
1721                                 *p++ = '\t';
1722
1723                         if (conv(&neg, &lval, i, 0, data))
1724                                 break;
1725
1726                         sprintf(p, "%s%lu", neg ? "-" : "", lval);
1727                         len = strlen(buf);
1728                         if (len > left)
1729                                 len = left;
1730                         if(copy_to_user(s, buf, len))
1731                                 return -EFAULT;
1732                         left -= len;
1733                         s += len;
1734                 }
1735         }
1736
1737         if (!write && !first && left) {
1738                 if(put_user('\n', s))
1739                         return -EFAULT;
1740                 left--, s++;
1741         }
1742         if (write) {
1743                 while (left) {
1744                         char c;
1745                         if (get_user(c, s++))
1746                                 return -EFAULT;
1747                         if (!isspace(c))
1748                                 break;
1749                         left--;
1750                 }
1751         }
1752         if (write && first)
1753                 return -EINVAL;
1754         *lenp -= left;
1755         *ppos += *lenp;
1756         return 0;
1757 #undef TMPBUFLEN
1758 }
1759
1760 /**
1761  * proc_dointvec - read a vector of integers
1762  * @table: the sysctl table
1763  * @write: %TRUE if this is a write to the sysctl file
1764  * @filp: the file structure
1765  * @buffer: the user buffer
1766  * @lenp: the size of the user buffer
1767  * @ppos: file position
1768  *
1769  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1770  * values from/to the user buffer, treated as an ASCII string.
1771  *
1772  * Returns 0 on success.
1773  */
1774 int proc_dointvec(ctl_table *table, int write, struct file *filp,
1775                      void __user *buffer, size_t *lenp, loff_t *ppos)
1776 {
1777     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1778                             NULL,NULL);
1779 }
1780
1781 #define OP_SET  0
1782 #define OP_AND  1
1783 #define OP_OR   2
1784 #define OP_MAX  3
1785 #define OP_MIN  4
1786
1787 static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp,
1788                                       int *valp,
1789                                       int write, void *data)
1790 {
1791         int op = *(int *)data;
1792         if (write) {
1793                 int val = *negp ? -*lvalp : *lvalp;
1794                 switch(op) {
1795                 case OP_SET:    *valp = val; break;
1796                 case OP_AND:    *valp &= val; break;
1797                 case OP_OR:     *valp |= val; break;
1798                 case OP_MAX:    if(*valp < val)
1799                                         *valp = val;
1800                                 break;
1801                 case OP_MIN:    if(*valp > val)
1802                                 *valp = val;
1803                                 break;
1804                 }
1805         } else {
1806                 int val = *valp;
1807                 if (val < 0) {
1808                         *negp = -1;
1809                         *lvalp = (unsigned long)-val;
1810                 } else {
1811                         *negp = 0;
1812                         *lvalp = (unsigned long)val;
1813                 }
1814         }
1815         return 0;
1816 }
1817
1818 /*
1819  *      init may raise the set.
1820  */
1821
1822 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
1823                         void __user *buffer, size_t *lenp, loff_t *ppos)
1824 {
1825         int op;
1826
1827         if (!capable(CAP_SYS_MODULE)) {
1828                 return -EPERM;
1829         }
1830
1831         op = (current->pid == 1) ? OP_SET : OP_AND;
1832         return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1833                                 do_proc_dointvec_bset_conv,&op);
1834 }
1835
1836 struct do_proc_dointvec_minmax_conv_param {
1837         int *min;
1838         int *max;
1839 };
1840
1841 static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp,
1842                                         int *valp,
1843                                         int write, void *data)
1844 {
1845         struct do_proc_dointvec_minmax_conv_param *param = data;
1846         if (write) {
1847                 int val = *negp ? -*lvalp : *lvalp;
1848                 if ((param->min && *param->min > val) ||
1849                     (param->max && *param->max < val))
1850                         return -EINVAL;
1851                 *valp = val;
1852         } else {
1853                 int val = *valp;
1854                 if (val < 0) {
1855                         *negp = -1;
1856                         *lvalp = (unsigned long)-val;
1857                 } else {
1858                         *negp = 0;
1859                         *lvalp = (unsigned long)val;
1860                 }
1861         }
1862         return 0;
1863 }
1864
1865 /**
1866  * proc_dointvec_minmax - read a vector of integers with min/max values
1867  * @table: the sysctl table
1868  * @write: %TRUE if this is a write to the sysctl file
1869  * @filp: the file structure
1870  * @buffer: the user buffer
1871  * @lenp: the size of the user buffer
1872  * @ppos: file position
1873  *
1874  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1875  * values from/to the user buffer, treated as an ASCII string.
1876  *
1877  * This routine will ensure the values are within the range specified by
1878  * table->extra1 (min) and table->extra2 (max).
1879  *
1880  * Returns 0 on success.
1881  */
1882 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
1883                   void __user *buffer, size_t *lenp, loff_t *ppos)
1884 {
1885         struct do_proc_dointvec_minmax_conv_param param = {
1886                 .min = (int *) table->extra1,
1887                 .max = (int *) table->extra2,
1888         };
1889         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
1890                                 do_proc_dointvec_minmax_conv, &param);
1891 }
1892
1893 static int do_proc_doulongvec_minmax(ctl_table *table, int write,
1894                                      struct file *filp,
1895                                      void __user *buffer,
1896                                      size_t *lenp, loff_t *ppos,
1897                                      unsigned long convmul,
1898                                      unsigned long convdiv)
1899 {
1900 #define TMPBUFLEN 21
1901         unsigned long *i, *min, *max, val;
1902         int vleft, first=1, neg;
1903         size_t len, left;
1904         char buf[TMPBUFLEN], *p;
1905         char __user *s = buffer;
1906
1907         if (!table->data || !table->maxlen || !*lenp ||
1908             (*ppos && !write)) {
1909                 *lenp = 0;
1910                 return 0;
1911         }
1912
1913         i = (unsigned long *) table->data;
1914         min = (unsigned long *) table->extra1;
1915         max = (unsigned long *) table->extra2;
1916         vleft = table->maxlen / sizeof(unsigned long);
1917         left = *lenp;
1918
1919         for (; left && vleft--; i++, min++, max++, first=0) {
1920                 if (write) {
1921                         while (left) {
1922                                 char c;
1923                                 if (get_user(c, s))
1924                                         return -EFAULT;
1925                                 if (!isspace(c))
1926                                         break;
1927                                 left--;
1928                                 s++;
1929                         }
1930                         if (!left)
1931                                 break;
1932                         neg = 0;
1933                         len = left;
1934                         if (len > TMPBUFLEN-1)
1935                                 len = TMPBUFLEN-1;
1936                         if (copy_from_user(buf, s, len))
1937                                 return -EFAULT;
1938                         buf[len] = 0;
1939                         p = buf;
1940                         if (*p == '-' && left > 1) {
1941                                 neg = 1;
1942                                 left--, p++;
1943                         }
1944                         if (*p < '0' || *p > '9')
1945                                 break;
1946                         val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
1947                         len = p-buf;
1948                         if ((len < left) && *p && !isspace(*p))
1949                                 break;
1950                         if (neg)
1951                                 val = -val;
1952                         s += len;
1953                         left -= len;
1954
1955                         if(neg)
1956                                 continue;
1957                         if ((min && val < *min) || (max && val > *max))
1958                                 continue;
1959                         *i = val;
1960                 } else {
1961                         p = buf;
1962                         if (!first)
1963                                 *p++ = '\t';
1964                         sprintf(p, "%lu", convdiv * (*i) / convmul);
1965                         len = strlen(buf);
1966                         if (len > left)
1967                                 len = left;
1968                         if(copy_to_user(s, buf, len))
1969                                 return -EFAULT;
1970                         left -= len;
1971                         s += len;
1972                 }
1973         }
1974
1975         if (!write && !first && left) {
1976                 if(put_user('\n', s))
1977                         return -EFAULT;
1978                 left--, s++;
1979         }
1980         if (write) {
1981                 while (left) {
1982                         char c;
1983                         if (get_user(c, s++))
1984                                 return -EFAULT;
1985                         if (!isspace(c))
1986                                 break;
1987                         left--;
1988                 }
1989         }
1990         if (write && first)
1991                 return -EINVAL;
1992         *lenp -= left;
1993         *ppos += *lenp;
1994         return 0;
1995 #undef TMPBUFLEN
1996 }
1997
1998 /**
1999  * proc_doulongvec_minmax - read a vector of long integers with min/max values
2000  * @table: the sysctl table
2001  * @write: %TRUE if this is a write to the sysctl file
2002  * @filp: the file structure
2003  * @buffer: the user buffer
2004  * @lenp: the size of the user buffer
2005  * @ppos: file position
2006  *
2007  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2008  * values from/to the user buffer, treated as an ASCII string.
2009  *
2010  * This routine will ensure the values are within the range specified by
2011  * table->extra1 (min) and table->extra2 (max).
2012  *
2013  * Returns 0 on success.
2014  */
2015 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2016                            void __user *buffer, size_t *lenp, loff_t *ppos)
2017 {
2018     return do_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos, 1l, 1l);
2019 }
2020
2021 /**
2022  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2023  * @table: the sysctl table
2024  * @write: %TRUE if this is a write to the sysctl file
2025  * @filp: the file structure
2026  * @buffer: the user buffer
2027  * @lenp: the size of the user buffer
2028  * @ppos: file position
2029  *
2030  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2031  * values from/to the user buffer, treated as an ASCII string. The values
2032  * are treated as milliseconds, and converted to jiffies when they are stored.
2033  *
2034  * This routine will ensure the values are within the range specified by
2035  * table->extra1 (min) and table->extra2 (max).
2036  *
2037  * Returns 0 on success.
2038  */
2039 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2040                                       struct file *filp,
2041                                       void __user *buffer,
2042                                       size_t *lenp, loff_t *ppos)
2043 {
2044     return do_proc_doulongvec_minmax(table, write, filp, buffer,
2045                                      lenp, ppos, HZ, 1000l);
2046 }
2047
2048
2049 static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
2050                                          int *valp,
2051                                          int write, void *data)
2052 {
2053         if (write) {
2054                 if (*lvalp > LONG_MAX / HZ)
2055                         return 1;
2056                 *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2057         } else {
2058                 int val = *valp;
2059                 unsigned long lval;
2060                 if (val < 0) {
2061                         *negp = -1;
2062                         lval = (unsigned long)-val;
2063                 } else {
2064                         *negp = 0;
2065                         lval = (unsigned long)val;
2066                 }
2067                 *lvalp = lval / HZ;
2068         }
2069         return 0;
2070 }
2071
2072 static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
2073                                                 int *valp,
2074                                                 int write, void *data)
2075 {
2076         if (write) {
2077                 if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2078                         return 1;
2079                 *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2080         } else {
2081                 int val = *valp;
2082                 unsigned long lval;
2083                 if (val < 0) {
2084                         *negp = -1;
2085                         lval = (unsigned long)-val;
2086                 } else {
2087                         *negp = 0;
2088                         lval = (unsigned long)val;
2089                 }
2090                 *lvalp = jiffies_to_clock_t(lval);
2091         }
2092         return 0;
2093 }
2094
2095 static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
2096                                             int *valp,
2097                                             int write, void *data)
2098 {
2099         if (write) {
2100                 *valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2101         } else {
2102                 int val = *valp;
2103                 unsigned long lval;
2104                 if (val < 0) {
2105                         *negp = -1;
2106                         lval = (unsigned long)-val;
2107                 } else {
2108                         *negp = 0;
2109                         lval = (unsigned long)val;
2110                 }
2111                 *lvalp = jiffies_to_msecs(lval);
2112         }
2113         return 0;
2114 }
2115
2116 /**
2117  * proc_dointvec_jiffies - read a vector of integers as seconds
2118  * @table: the sysctl table
2119  * @write: %TRUE if this is a write to the sysctl file
2120  * @filp: the file structure
2121  * @buffer: the user buffer
2122  * @lenp: the size of the user buffer
2123  * @ppos: file position
2124  *
2125  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2126  * values from/to the user buffer, treated as an ASCII string.
2127  * The values read are assumed to be in seconds, and are converted into
2128  * jiffies.
2129  *
2130  * Returns 0 on success.
2131  */
2132 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2133                           void __user *buffer, size_t *lenp, loff_t *ppos)
2134 {
2135     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2136                             do_proc_dointvec_jiffies_conv,NULL);
2137 }
2138
2139 /**
2140  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2141  * @table: the sysctl table
2142  * @write: %TRUE if this is a write to the sysctl file
2143  * @filp: the file structure
2144  * @buffer: the user buffer
2145  * @lenp: the size of the user buffer
2146  * @ppos: pointer to the file position
2147  *
2148  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2149  * values from/to the user buffer, treated as an ASCII string.
2150  * The values read are assumed to be in 1/USER_HZ seconds, and
2151  * are converted into jiffies.
2152  *
2153  * Returns 0 on success.
2154  */
2155 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2156                                  void __user *buffer, size_t *lenp, loff_t *ppos)
2157 {
2158     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2159                             do_proc_dointvec_userhz_jiffies_conv,NULL);
2160 }
2161
2162 /**
2163  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2164  * @table: the sysctl table
2165  * @write: %TRUE if this is a write to the sysctl file
2166  * @filp: the file structure
2167  * @buffer: the user buffer
2168  * @lenp: the size of the user buffer
2169  * @ppos: file position
2170  * @ppos: the current position in the file
2171  *
2172  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2173  * values from/to the user buffer, treated as an ASCII string.
2174  * The values read are assumed to be in 1/1000 seconds, and
2175  * are converted into jiffies.
2176  *
2177  * Returns 0 on success.
2178  */
2179 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2180                              void __user *buffer, size_t *lenp, loff_t *ppos)
2181 {
2182         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
2183                                 do_proc_dointvec_ms_jiffies_conv, NULL);
2184 }
2185
2186 #else /* CONFIG_PROC_FS */
2187
2188 int proc_dostring(ctl_table *table, int write, struct file *filp,
2189                   void __user *buffer, size_t *lenp, loff_t *ppos)
2190 {
2191         return -ENOSYS;
2192 }
2193
2194 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
2195                             void __user *buffer, size_t *lenp, loff_t *ppos)
2196 {
2197         return -ENOSYS;
2198 }
2199
2200 int proc_dointvec(ctl_table *table, int write, struct file *filp,
2201                   void __user *buffer, size_t *lenp, loff_t *ppos)
2202 {
2203         return -ENOSYS;
2204 }
2205
2206 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
2207                         void __user *buffer, size_t *lenp, loff_t *ppos)
2208 {
2209         return -ENOSYS;
2210 }
2211
2212 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
2213                     void __user *buffer, size_t *lenp, loff_t *ppos)
2214 {
2215         return -ENOSYS;
2216 }
2217
2218 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2219                     void __user *buffer, size_t *lenp, loff_t *ppos)
2220 {
2221         return -ENOSYS;
2222 }
2223
2224 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2225                     void __user *buffer, size_t *lenp, loff_t *ppos)
2226 {
2227         return -ENOSYS;
2228 }
2229
2230 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2231                              void __user *buffer, size_t *lenp, loff_t *ppos)
2232 {
2233         return -ENOSYS;
2234 }
2235
2236 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2237                     void __user *buffer, size_t *lenp, loff_t *ppos)
2238 {
2239         return -ENOSYS;
2240 }
2241
2242 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2243                                       struct file *filp,
2244                                       void __user *buffer,
2245                                       size_t *lenp, loff_t *ppos)
2246 {
2247     return -ENOSYS;
2248 }
2249
2250
2251 #endif /* CONFIG_PROC_FS */
2252
2253
2254 /*
2255  * General sysctl support routines
2256  */
2257
2258 /* The generic string strategy routine: */
2259 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2260                   void __user *oldval, size_t __user *oldlenp,
2261                   void __user *newval, size_t newlen, void **context)
2262 {
2263         if (!table->data || !table->maxlen)
2264                 return -ENOTDIR;
2265
2266         if (oldval && oldlenp) {
2267                 size_t bufsize;
2268                 if (get_user(bufsize, oldlenp))
2269                         return -EFAULT;
2270                 if (bufsize) {
2271                         size_t len = strlen(table->data), copied;
2272
2273                         /* This shouldn't trigger for a well-formed sysctl */
2274                         if (len > table->maxlen)
2275                                 len = table->maxlen;
2276
2277                         /* Copy up to a max of bufsize-1 bytes of the string */
2278                         copied = (len >= bufsize) ? bufsize - 1 : len;
2279
2280                         if (copy_to_user(oldval, table->data, copied) ||
2281                             put_user(0, (char __user *)(oldval + copied)))
2282                                 return -EFAULT;
2283                         if (put_user(len, oldlenp))
2284                                 return -EFAULT;
2285                 }
2286         }
2287         if (newval && newlen) {
2288                 size_t len = newlen;
2289                 if (len > table->maxlen)
2290                         len = table->maxlen;
2291                 if(copy_from_user(table->data, newval, len))
2292                         return -EFAULT;
2293                 if (len == table->maxlen)
2294                         len--;
2295                 ((char *) table->data)[len] = 0;
2296         }
2297         return 1;
2298 }
2299
2300 /*
2301  * This function makes sure that all of the integers in the vector
2302  * are between the minimum and maximum values given in the arrays
2303  * table->extra1 and table->extra2, respectively.
2304  */
2305 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2306                 void __user *oldval, size_t __user *oldlenp,
2307                 void __user *newval, size_t newlen, void **context)
2308 {
2309
2310         if (newval && newlen) {
2311                 int __user *vec = (int __user *) newval;
2312                 int *min = (int *) table->extra1;
2313                 int *max = (int *) table->extra2;
2314                 size_t length;
2315                 int i;
2316
2317                 if (newlen % sizeof(int) != 0)
2318                         return -EINVAL;
2319
2320                 if (!table->extra1 && !table->extra2)
2321                         return 0;
2322
2323                 if (newlen > table->maxlen)
2324                         newlen = table->maxlen;
2325                 length = newlen / sizeof(int);
2326
2327                 for (i = 0; i < length; i++) {
2328                         int value;
2329                         if (get_user(value, vec + i))
2330                                 return -EFAULT;
2331                         if (min && value < min[i])
2332                                 return -EINVAL;
2333                         if (max && value > max[i])
2334                                 return -EINVAL;
2335                 }
2336         }
2337         return 0;
2338 }
2339
2340 /* Strategy function to convert jiffies to seconds */
2341 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2342                 void __user *oldval, size_t __user *oldlenp,
2343                 void __user *newval, size_t newlen, void **context)
2344 {
2345         if (oldval) {
2346                 size_t olen;
2347                 if (oldlenp) {
2348                         if (get_user(olen, oldlenp))
2349                                 return -EFAULT;
2350                         if (olen!=sizeof(int))
2351                                 return -EINVAL;
2352                 }
2353                 if (put_user(*(int *)(table->data)/HZ, (int __user *)oldval) ||
2354                     (oldlenp && put_user(sizeof(int),oldlenp)))
2355                         return -EFAULT;
2356         }
2357         if (newval && newlen) {
2358                 int new;
2359                 if (newlen != sizeof(int))
2360                         return -EINVAL;
2361                 if (get_user(new, (int __user *)newval))
2362                         return -EFAULT;
2363                 *(int *)(table->data) = new*HZ;
2364         }
2365         return 1;
2366 }
2367
2368 /* Strategy function to convert jiffies to seconds */
2369 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2370                 void __user *oldval, size_t __user *oldlenp,
2371                 void __user *newval, size_t newlen, void **context)
2372 {
2373         if (oldval) {
2374                 size_t olen;
2375                 if (oldlenp) {
2376                         if (get_user(olen, oldlenp))
2377                                 return -EFAULT;
2378                         if (olen!=sizeof(int))
2379                                 return -EINVAL;
2380                 }
2381                 if (put_user(jiffies_to_msecs(*(int *)(table->data)), (int __user *)oldval) ||
2382                     (oldlenp && put_user(sizeof(int),oldlenp)))
2383                         return -EFAULT;
2384         }
2385         if (newval && newlen) {
2386                 int new;
2387                 if (newlen != sizeof(int))
2388                         return -EINVAL;
2389                 if (get_user(new, (int __user *)newval))
2390                         return -EFAULT;
2391                 *(int *)(table->data) = msecs_to_jiffies(new);
2392         }
2393         return 1;
2394 }
2395
2396 #else /* CONFIG_SYSCTL */
2397
2398
2399 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
2400 {
2401         return -ENOSYS;
2402 }
2403
2404 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2405                   void __user *oldval, size_t __user *oldlenp,
2406                   void __user *newval, size_t newlen, void **context)
2407 {
2408         return -ENOSYS;
2409 }
2410
2411 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2412                 void __user *oldval, size_t __user *oldlenp,
2413                 void __user *newval, size_t newlen, void **context)
2414 {
2415         return -ENOSYS;
2416 }
2417
2418 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2419                 void __user *oldval, size_t __user *oldlenp,
2420                 void __user *newval, size_t newlen, void **context)
2421 {
2422         return -ENOSYS;
2423 }
2424
2425 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2426                 void __user *oldval, size_t __user *oldlenp,
2427                 void __user *newval, size_t newlen, void **context)
2428 {
2429         return -ENOSYS;
2430 }
2431
2432 int proc_dostring(ctl_table *table, int write, struct file *filp,
2433                   void __user *buffer, size_t *lenp, loff_t *ppos)
2434 {
2435         return -ENOSYS;
2436 }
2437
2438 int proc_dointvec(ctl_table *table, int write, struct file *filp,
2439                   void __user *buffer, size_t *lenp, loff_t *ppos)
2440 {
2441         return -ENOSYS;
2442 }
2443
2444 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
2445                         void __user *buffer, size_t *lenp, loff_t *ppos)
2446 {
2447         return -ENOSYS;
2448 }
2449
2450 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
2451                     void __user *buffer, size_t *lenp, loff_t *ppos)
2452 {
2453         return -ENOSYS;
2454 }
2455
2456 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2457                           void __user *buffer, size_t *lenp, loff_t *ppos)
2458 {
2459         return -ENOSYS;
2460 }
2461
2462 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2463                           void __user *buffer, size_t *lenp, loff_t *ppos)
2464 {
2465         return -ENOSYS;
2466 }
2467
2468 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2469                              void __user *buffer, size_t *lenp, loff_t *ppos)
2470 {
2471         return -ENOSYS;
2472 }
2473
2474 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2475                     void __user *buffer, size_t *lenp, loff_t *ppos)
2476 {
2477         return -ENOSYS;
2478 }
2479
2480 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2481                                       struct file *filp,
2482                                       void __user *buffer,
2483                                       size_t *lenp, loff_t *ppos)
2484 {
2485     return -ENOSYS;
2486 }
2487
2488 struct ctl_table_header * register_sysctl_table(ctl_table * table,
2489                                                 int insert_at_head)
2490 {
2491         return NULL;
2492 }
2493
2494 void unregister_sysctl_table(struct ctl_table_header * table)
2495 {
2496 }
2497
2498 #endif /* CONFIG_SYSCTL */
2499
2500 /*
2501  * No sense putting this after each symbol definition, twice,
2502  * exception granted :-)
2503  */
2504 EXPORT_SYMBOL(proc_dointvec);
2505 EXPORT_SYMBOL(proc_dointvec_jiffies);
2506 EXPORT_SYMBOL(proc_dointvec_minmax);
2507 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2508 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2509 EXPORT_SYMBOL(proc_dostring);
2510 EXPORT_SYMBOL(proc_doulongvec_minmax);
2511 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2512 EXPORT_SYMBOL(register_sysctl_table);
2513 EXPORT_SYMBOL(sysctl_intvec);
2514 EXPORT_SYMBOL(sysctl_jiffies);
2515 EXPORT_SYMBOL(sysctl_ms_jiffies);
2516 EXPORT_SYMBOL(sysctl_string);
2517 EXPORT_SYMBOL(unregister_sysctl_table);