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 max_threads;
  63 extern int sysrq_enabled;
  64 extern int core_uses_pid;
  65 extern int suid_dumpable;
  66 extern char core_pattern[];
  67 extern int cad_pid;
  68 extern int pid_max;
  69 extern int min_free_kbytes;
  70 extern int printk_ratelimit_jiffies;
  71 extern int printk_ratelimit_burst;
  72 extern int pid_max_min, pid_max_max;
  73 extern int sysctl_drop_caches;
  74 extern int percpu_pagelist_fraction;
  75
  76 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
  77 int unknown_nmi_panic;
  78 extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *,
  79                                   void __user *, size_t *, loff_t *);
  80 #endif
  81
  82 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
  83 static int maxolduid = 65535;
  84 static int minolduid;
  85 static int min_percpu_pagelist_fract = 8;
  86
  87 static int ngroups_max = NGROUPS_MAX;
  88
  89 #ifdef CONFIG_KMOD
  90 extern char modprobe_path[];
  91 #endif
  92 #ifdef CONFIG_CHR_DEV_SG
  93 extern int sg_big_buff;
  94 #endif
  95 #ifdef CONFIG_SYSVIPC
  96 extern size_t shm_ctlmax;
  97 extern size_t shm_ctlall;
  98 extern int shm_ctlmni;
  99 extern int msg_ctlmax;
 100 extern int msg_ctlmnb;
 101 extern int msg_ctlmni;
 102 extern int sem_ctls[];
 103 #endif
 104
 105 #ifdef __sparc__
 106 extern char reboot_command [];
 107 extern int stop_a_enabled;
 108 extern int scons_pwroff;
 109 #endif
 110
 111 #ifdef __hppa__
 112 extern int pwrsw_enabled;
 113 extern int unaligned_enabled;
 114 #endif
 115
 116 #ifdef CONFIG_S390
 117 #ifdef CONFIG_MATHEMU
 118 extern int sysctl_ieee_emulation_warnings;
 119 #endif
 120 extern int sysctl_userprocess_debug;
 121 extern int spin_retry;
 122 #endif
 123
 124 extern int sysctl_hz_timer;
 125
 126 #ifdef CONFIG_BSD_PROCESS_ACCT
 127 extern int acct_parm[];
 128 #endif
 129
 130 #ifdef CONFIG_IA64
 131 extern int no_unaligned_warning;
 132 #endif
 133
 134 static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t,
 135                        ctl_table *, void **);
 136 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
 137                   void __user *buffer, size_t *lenp, loff_t *ppos);
 138
 139 static ctl_table root_table[];
 140 static struct ctl_table_header root_table_header =
 141         { root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };
 142
 143 static ctl_table kern_table[];
 144 static ctl_table vm_table[];
 145 static ctl_table proc_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
 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_PROC,
 206                 .procname       = "proc",
 207                 .mode           = 0555,
 208                 .child          = proc_table,
 209         },
 210         {
 211                 .ctl_name       = CTL_FS,
 212                 .procname       = "fs",
 213                 .mode           = 0555,
 214                 .child          = fs_table,
 215         },
 216         {
 217                 .ctl_name       = CTL_DEBUG,
 218                 .procname       = "debug",
 219                 .mode           = 0555,
 220                 .child          = debug_table,
 221         },
 222         {
 223                 .ctl_name       = CTL_DEV,
 224                 .procname       = "dev",
 225                 .mode           = 0555,
 226                 .child          = dev_table,
 227         },
 228
 229         { .ctl_name = 0 }
 230 };
 231
 232 static ctl_table kern_table[] = {
 233         {
 234                 .ctl_name       = KERN_OSTYPE,
 235                 .procname       = "ostype",
 236                 .data           = system_utsname.sysname,
 237                 .maxlen         = sizeof(system_utsname.sysname),
 238                 .mode           = 0444,
 239                 .proc_handler   = &proc_doutsstring,
 240                 .strategy       = &sysctl_string,
 241         },
 242         {
 243                 .ctl_name       = KERN_OSRELEASE,
 244                 .procname       = "osrelease",
 245                 .data           = system_utsname.release,
 246                 .maxlen         = sizeof(system_utsname.release),
 247                 .mode           = 0444,
 248                 .proc_handler   = &proc_doutsstring,
 249                 .strategy       = &sysctl_string,
 250         },
 251         {
 252                 .ctl_name       = KERN_VERSION,
 253                 .procname       = "version",
 254                 .data           = system_utsname.version,
 255                 .maxlen         = sizeof(system_utsname.version),
 256                 .mode           = 0444,
 257                 .proc_handler   = &proc_doutsstring,
 258                 .strategy       = &sysctl_string,
 259         },
 260         {
 261                 .ctl_name       = KERN_NODENAME,
 262                 .procname       = "hostname",
 263                 .data           = system_utsname.nodename,
 264                 .maxlen         = sizeof(system_utsname.nodename),
 265                 .mode           = 0644,
 266                 .proc_handler   = &proc_doutsstring,
 267                 .strategy       = &sysctl_string,
 268         },
 269         {
 270                 .ctl_name       = KERN_DOMAINNAME,
 271                 .procname       = "domainname",
 272                 .data           = system_utsname.domainname,
 273                 .maxlen         = sizeof(system_utsname.domainname),
 274                 .mode           = 0644,
 275                 .proc_handler   = &proc_doutsstring,
 276                 .strategy       = &sysctl_string,
 277         },
 278         {
 279                 .ctl_name       = KERN_PANIC,
 280                 .procname       = "panic",
 281                 .data           = &panic_timeout,
 282                 .maxlen         = sizeof(int),
 283                 .mode           = 0644,
 284                 .proc_handler   = &proc_dointvec,
 285         },
 286         {
 287                 .ctl_name       = KERN_CORE_USES_PID,
 288                 .procname       = "core_uses_pid",
 289                 .data           = &core_uses_pid,
 290                 .maxlen         = sizeof(int),
 291                 .mode           = 0644,
 292                 .proc_handler   = &proc_dointvec,
 293         },
 294         {
 295                 .ctl_name       = KERN_CORE_PATTERN,
 296                 .procname       = "core_pattern",
 297                 .data           = core_pattern,
 298                 .maxlen         = 64,
 299                 .mode           = 0644,
 300                 .proc_handler   = &proc_dostring,
 301                 .strategy       = &sysctl_string,
 302         },
 303         {
 304                 .ctl_name       = KERN_TAINTED,
 305                 .procname       = "tainted",
 306                 .data           = &tainted,
 307                 .maxlen         = sizeof(int),
 308                 .mode           = 0444,
 309                 .proc_handler   = &proc_dointvec,
 310         },
 311         {
 312                 .ctl_name       = KERN_CAP_BSET,
 313                 .procname       = "cap-bound",
 314                 .data           = &cap_bset,
 315                 .maxlen         = sizeof(kernel_cap_t),
 316                 .mode           = 0600,
 317                 .proc_handler   = &proc_dointvec_bset,
 318         },
 319 #ifdef CONFIG_BLK_DEV_INITRD
 320         {
 321                 .ctl_name       = KERN_REALROOTDEV,
 322                 .procname       = "real-root-dev",
 323                 .data           = &real_root_dev,
 324                 .maxlen         = sizeof(int),
 325                 .mode           = 0644,
 326                 .proc_handler   = &proc_dointvec,
 327         },
 328 #endif
 329 #ifdef __sparc__
 330         {
 331                 .ctl_name       = KERN_SPARC_REBOOT,
 332                 .procname       = "reboot-cmd",
 333                 .data           = reboot_command,
 334                 .maxlen         = 256,
 335                 .mode           = 0644,
 336                 .proc_handler   = &proc_dostring,
 337                 .strategy       = &sysctl_string,
 338         },
 339         {
 340                 .ctl_name       = KERN_SPARC_STOP_A,
 341                 .procname       = "stop-a",
 342                 .data           = &stop_a_enabled,
 343                 .maxlen         = sizeof (int),
 344                 .mode           = 0644,
 345                 .proc_handler   = &proc_dointvec,
 346         },
 347         {
 348                 .ctl_name       = KERN_SPARC_SCONS_PWROFF,
 349                 .procname       = "scons-poweroff",
 350                 .data           = &scons_pwroff,
 351                 .maxlen         = sizeof (int),
 352                 .mode           = 0644,
 353                 .proc_handler   = &proc_dointvec,
 354         },
 355 #endif
 356 #ifdef __hppa__
 357         {
 358                 .ctl_name       = KERN_HPPA_PWRSW,
 359                 .procname       = "soft-power",
 360                 .data           = &pwrsw_enabled,
 361                 .maxlen         = sizeof (int),
 362                 .mode           = 0644,
 363                 .proc_handler   = &proc_dointvec,
 364         },
 365         {
 366                 .ctl_name       = KERN_HPPA_UNALIGNED,
 367                 .procname       = "unaligned-trap",
 368                 .data           = &unaligned_enabled,
 369                 .maxlen         = sizeof (int),
 370                 .mode           = 0644,
 371                 .proc_handler   = &proc_dointvec,
 372         },
 373 #endif
 374         {
 375                 .ctl_name       = KERN_CTLALTDEL,
 376                 .procname       = "ctrl-alt-del",
 377                 .data           = &C_A_D,
 378                 .maxlen         = sizeof(int),
 379                 .mode           = 0644,
 380                 .proc_handler   = &proc_dointvec,
 381         },
 382         {
 383                 .ctl_name       = KERN_PRINTK,
 384                 .procname       = "printk",
 385                 .data           = &console_loglevel,
 386                 .maxlen         = 4*sizeof(int),
 387                 .mode           = 0644,
 388                 .proc_handler   = &proc_dointvec,
 389         },
 390 #ifdef CONFIG_KMOD
 391         {
 392                 .ctl_name       = KERN_MODPROBE,
 393                 .procname       = "modprobe",
 394                 .data           = &modprobe_path,
 395                 .maxlen         = KMOD_PATH_LEN,
 396                 .mode           = 0644,
 397                 .proc_handler   = &proc_dostring,
 398                 .strategy       = &sysctl_string,
 399         },
 400 #endif
 401 #ifdef CONFIG_HOTPLUG
 402         {
 403                 .ctl_name       = KERN_HOTPLUG,
 404                 .procname       = "hotplug",
 405                 .data           = &uevent_helper,
 406                 .maxlen         = UEVENT_HELPER_PATH_LEN,
 407                 .mode           = 0644,
 408                 .proc_handler   = &proc_dostring,
 409                 .strategy       = &sysctl_string,
 410         },
 411 #endif
 412 #ifdef CONFIG_CHR_DEV_SG
 413         {
 414                 .ctl_name       = KERN_SG_BIG_BUFF,
 415                 .procname       = "sg-big-buff",
 416                 .data           = &sg_big_buff,
 417                 .maxlen         = sizeof (int),
 418                 .mode           = 0444,
 419                 .proc_handler   = &proc_dointvec,
 420         },
 421 #endif
 422 #ifdef CONFIG_BSD_PROCESS_ACCT
 423         {
 424                 .ctl_name       = KERN_ACCT,
 425                 .procname       = "acct",
 426                 .data           = &acct_parm,
 427                 .maxlen         = 3*sizeof(int),
 428                 .mode           = 0644,
 429                 .proc_handler   = &proc_dointvec,
 430         },
 431 #endif
 432 #ifdef CONFIG_SYSVIPC
 433         {
 434                 .ctl_name       = KERN_SHMMAX,
 435                 .procname       = "shmmax",
 436                 .data           = &shm_ctlmax,
 437                 .maxlen         = sizeof (size_t),
 438                 .mode           = 0644,
 439                 .proc_handler   = &proc_doulongvec_minmax,
 440         },
 441         {
 442                 .ctl_name       = KERN_SHMALL,
 443                 .procname       = "shmall",
 444                 .data           = &shm_ctlall,
 445                 .maxlen         = sizeof (size_t),
 446                 .mode           = 0644,
 447                 .proc_handler   = &proc_doulongvec_minmax,
 448         },
 449         {
 450                 .ctl_name       = KERN_SHMMNI,
 451                 .procname       = "shmmni",
 452                 .data           = &shm_ctlmni,
 453                 .maxlen         = sizeof (int),
 454                 .mode           = 0644,
 455                 .proc_handler   = &proc_dointvec,
 456         },
 457         {
 458                 .ctl_name       = KERN_MSGMAX,
 459                 .procname       = "msgmax",
 460                 .data           = &msg_ctlmax,
 461                 .maxlen         = sizeof (int),
 462                 .mode           = 0644,
 463                 .proc_handler   = &proc_dointvec,
 464         },
 465         {
 466                 .ctl_name       = KERN_MSGMNI,
 467                 .procname       = "msgmni",
 468                 .data           = &msg_ctlmni,
 469                 .maxlen         = sizeof (int),
 470                 .mode           = 0644,
 471                 .proc_handler   = &proc_dointvec,
 472         },
 473         {
 474                 .ctl_name       = KERN_MSGMNB,
 475                 .procname       =  "msgmnb",
 476                 .data           = &msg_ctlmnb,
 477                 .maxlen         = sizeof (int),
 478                 .mode           = 0644,
 479                 .proc_handler   = &proc_dointvec,
 480         },
 481         {
 482                 .ctl_name       = KERN_SEM,
 483                 .procname       = "sem",
 484                 .data           = &sem_ctls,
 485                 .maxlen         = 4*sizeof (int),
 486                 .mode           = 0644,
 487                 .proc_handler   = &proc_dointvec,
 488         },
 489 #endif
 490 #ifdef CONFIG_MAGIC_SYSRQ
 491         {
 492                 .ctl_name       = KERN_SYSRQ,
 493                 .procname       = "sysrq",
 494                 .data           = &sysrq_enabled,
 495                 .maxlen         = sizeof (int),
 496                 .mode           = 0644,
 497                 .proc_handler   = &proc_dointvec,
 498         },
 499 #endif
 500         {
 501                 .ctl_name       = KERN_CADPID,
 502                 .procname       = "cad_pid",
 503                 .data           = &cad_pid,
 504                 .maxlen         = sizeof (int),
 505                 .mode           = 0600,
 506                 .proc_handler   = &proc_dointvec,
 507         },
 508         {
 509                 .ctl_name       = KERN_MAX_THREADS,
 510                 .procname       = "threads-max",
 511                 .data           = &max_threads,
 512                 .maxlen         = sizeof(int),
 513                 .mode           = 0644,
 514                 .proc_handler   = &proc_dointvec,
 515         },
 516         {
 517                 .ctl_name       = KERN_RANDOM,
 518                 .procname       = "random",
 519                 .mode           = 0555,
 520                 .child          = random_table,
 521         },
 522 #ifdef CONFIG_UNIX98_PTYS
 523         {
 524                 .ctl_name       = KERN_PTY,
 525                 .procname       = "pty",
 526                 .mode           = 0555,
 527                 .child          = pty_table,
 528         },
 529 #endif
 530         {
 531                 .ctl_name       = KERN_OVERFLOWUID,
 532                 .procname       = "overflowuid",
 533                 .data           = &overflowuid,
 534                 .maxlen         = sizeof(int),
 535                 .mode           = 0644,
 536                 .proc_handler   = &proc_dointvec_minmax,
 537                 .strategy       = &sysctl_intvec,
 538                 .extra1         = &minolduid,
 539                 .extra2         = &maxolduid,
 540         },
 541         {
 542                 .ctl_name       = KERN_OVERFLOWGID,
 543                 .procname       = "overflowgid",
 544                 .data           = &overflowgid,
 545                 .maxlen         = sizeof(int),
 546                 .mode           = 0644,
 547                 .proc_handler   = &proc_dointvec_minmax,
 548                 .strategy       = &sysctl_intvec,
 549                 .extra1         = &minolduid,
 550                 .extra2         = &maxolduid,
 551         },
 552 #ifdef CONFIG_S390
 553 #ifdef CONFIG_MATHEMU
 554         {
 555                 .ctl_name       = KERN_IEEE_EMULATION_WARNINGS,
 556                 .procname       = "ieee_emulation_warnings",
 557                 .data           = &sysctl_ieee_emulation_warnings,
 558                 .maxlen         = sizeof(int),
 559                 .mode           = 0644,
 560                 .proc_handler   = &proc_dointvec,
 561         },
 562 #endif
 563 #ifdef CONFIG_NO_IDLE_HZ
 564         {
 565                 .ctl_name       = KERN_HZ_TIMER,
 566                 .procname       = "hz_timer",
 567                 .data           = &sysctl_hz_timer,
 568                 .maxlen         = sizeof(int),
 569                 .mode           = 0644,
 570                 .proc_handler   = &proc_dointvec,
 571         },
 572 #endif
 573         {
 574                 .ctl_name       = KERN_S390_USER_DEBUG_LOGGING,
 575                 .procname       = "userprocess_debug",
 576                 .data           = &sysctl_userprocess_debug,
 577                 .maxlen         = sizeof(int),
 578                 .mode           = 0644,
 579                 .proc_handler   = &proc_dointvec,
 580         },
 581 #endif
 582         {
 583                 .ctl_name       = KERN_PIDMAX,
 584                 .procname       = "pid_max",
 585                 .data           = &pid_max,
 586                 .maxlen         = sizeof (int),
 587                 .mode           = 0644,
 588                 .proc_handler   = &proc_dointvec_minmax,
 589                 .strategy       = sysctl_intvec,
 590                 .extra1         = &pid_max_min,
 591                 .extra2         = &pid_max_max,
 592         },
 593         {
 594                 .ctl_name       = KERN_PANIC_ON_OOPS,
 595                 .procname       = "panic_on_oops",
 596                 .data           = &panic_on_oops,
 597                 .maxlen         = sizeof(int),
 598                 .mode           = 0644,
 599                 .proc_handler   = &proc_dointvec,
 600         },
 601         {
 602                 .ctl_name       = KERN_PRINTK_RATELIMIT,
 603                 .procname       = "printk_ratelimit",
 604                 .data           = &printk_ratelimit_jiffies,
 605                 .maxlen         = sizeof(int),
 606                 .mode           = 0644,
 607                 .proc_handler   = &proc_dointvec_jiffies,
 608                 .strategy       = &sysctl_jiffies,
 609         },
 610         {
 611                 .ctl_name       = KERN_PRINTK_RATELIMIT_BURST,
 612                 .procname       = "printk_ratelimit_burst",
 613                 .data           = &printk_ratelimit_burst,
 614                 .maxlen         = sizeof(int),
 615                 .mode           = 0644,
 616                 .proc_handler   = &proc_dointvec,
 617         },
 618         {
 619                 .ctl_name       = KERN_NGROUPS_MAX,
 620                 .procname       = "ngroups_max",
 621                 .data           = &ngroups_max,
 622                 .maxlen         = sizeof (int),
 623                 .mode           = 0444,
 624                 .proc_handler   = &proc_dointvec,
 625         },
 626 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 627         {
 628                 .ctl_name       = KERN_UNKNOWN_NMI_PANIC,
 629                 .procname       = "unknown_nmi_panic",
 630                 .data           = &unknown_nmi_panic,
 631                 .maxlen         = sizeof (int),
 632                 .mode           = 0644,
 633                 .proc_handler   = &proc_unknown_nmi_panic,
 634         },
 635 #endif
 636 #if defined(CONFIG_X86)
 637         {
 638                 .ctl_name       = KERN_BOOTLOADER_TYPE,
 639                 .procname       = "bootloader_type",
 640                 .data           = &bootloader_type,
 641                 .maxlen         = sizeof (int),
 642                 .mode           = 0444,
 643                 .proc_handler   = &proc_dointvec,
 644         },
 645 #endif
 646 #if defined(CONFIG_MMU)
 647         {
 648                 .ctl_name       = KERN_RANDOMIZE,
 649                 .procname       = "randomize_va_space",
 650                 .data           = &randomize_va_space,
 651                 .maxlen         = sizeof(int),
 652                 .mode           = 0644,
 653                 .proc_handler   = &proc_dointvec,
 654         },
 655 #endif
 656 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
 657         {
 658                 .ctl_name       = KERN_SPIN_RETRY,
 659                 .procname       = "spin_retry",
 660                 .data           = &spin_retry,
 661                 .maxlen         = sizeof (int),
 662                 .mode           = 0644,
 663                 .proc_handler   = &proc_dointvec,
 664         },
 665 #endif
 666 #ifdef CONFIG_ACPI_SLEEP
 667         {
 668                 .ctl_name       = KERN_ACPI_VIDEO_FLAGS,
 669                 .procname       = "acpi_video_flags",
 670                 .data           = &acpi_video_flags,
 671                 .maxlen         = sizeof (unsigned long),
 672                 .mode           = 0644,
 673                 .proc_handler   = &proc_doulongvec_minmax,
 674         },
 675 #endif
 676 #ifdef CONFIG_IA64
 677         {
 678                 .ctl_name       = KERN_IA64_UNALIGNED,
 679                 .procname       = "ignore-unaligned-usertrap",
 680                 .data           = &no_unaligned_warning,
 681                 .maxlen         = sizeof (int),
 682                 .mode           = 0644,
 683                 .proc_handler   = &proc_dointvec,
 684         },
 685 #endif
 686         { .ctl_name = 0 }
 687 };
 688
 689 /* Constants for minimum and maximum testing in vm_table.
 690    We use these as one-element integer vectors. */
 691 static int zero;
 692 static int one_hundred = 100;
 693
 694
 695 static ctl_table vm_table[] = {
 696         {
 697                 .ctl_name       = VM_OVERCOMMIT_MEMORY,
 698                 .procname       = "overcommit_memory",
 699                 .data           = &sysctl_overcommit_memory,
 700                 .maxlen         = sizeof(sysctl_overcommit_memory),
 701                 .mode           = 0644,
 702                 .proc_handler   = &proc_dointvec,
 703         },
 704         {
 705                 .ctl_name       = VM_OVERCOMMIT_RATIO,
 706                 .procname       = "overcommit_ratio",
 707                 .data           = &sysctl_overcommit_ratio,
 708                 .maxlen         = sizeof(sysctl_overcommit_ratio),
 709                 .mode           = 0644,
 710                 .proc_handler   = &proc_dointvec,
 711         },
 712         {
 713                 .ctl_name       = VM_PAGE_CLUSTER,
 714                 .procname       = "page-cluster",
 715                 .data           = &page_cluster,
 716                 .maxlen         = sizeof(int),
 717                 .mode           = 0644,
 718                 .proc_handler   = &proc_dointvec,
 719         },
 720         {
 721                 .ctl_name       = VM_DIRTY_BACKGROUND,
 722                 .procname       = "dirty_background_ratio",
 723                 .data           = &dirty_background_ratio,
 724                 .maxlen         = sizeof(dirty_background_ratio),
 725                 .mode           = 0644,
 726                 .proc_handler   = &proc_dointvec_minmax,
 727                 .strategy       = &sysctl_intvec,
 728                 .extra1         = &zero,
 729                 .extra2         = &one_hundred,
 730         },
 731         {
 732                 .ctl_name       = VM_DIRTY_RATIO,
 733                 .procname       = "dirty_ratio",
 734                 .data           = &vm_dirty_ratio,
 735                 .maxlen         = sizeof(vm_dirty_ratio),
 736                 .mode           = 0644,
 737                 .proc_handler   = &proc_dointvec_minmax,
 738                 .strategy       = &sysctl_intvec,
 739                 .extra1         = &zero,
 740                 .extra2         = &one_hundred,
 741         },
 742         {
 743                 .ctl_name       = VM_DIRTY_WB_CS,
 744                 .procname       = "dirty_writeback_centisecs",
 745                 .data           = &dirty_writeback_centisecs,
 746                 .maxlen         = sizeof(dirty_writeback_centisecs),
 747                 .mode           = 0644,
 748                 .proc_handler   = &dirty_writeback_centisecs_handler,
 749         },
 750         {
 751                 .ctl_name       = VM_DIRTY_EXPIRE_CS,
 752                 .procname       = "dirty_expire_centisecs",
 753                 .data           = &dirty_expire_centisecs,
 754                 .maxlen         = sizeof(dirty_expire_centisecs),
 755                 .mode           = 0644,
 756                 .proc_handler   = &proc_dointvec,
 757         },
 758         {
 759                 .ctl_name       = VM_NR_PDFLUSH_THREADS,
 760                 .procname       = "nr_pdflush_threads",
 761                 .data           = &nr_pdflush_threads,
 762                 .maxlen         = sizeof nr_pdflush_threads,
 763                 .mode           = 0444 /* read-only*/,
 764                 .proc_handler   = &proc_dointvec,
 765         },
 766         {
 767                 .ctl_name       = VM_SWAPPINESS,
 768                 .procname       = "swappiness",
 769                 .data           = &vm_swappiness,
 770                 .maxlen         = sizeof(vm_swappiness),
 771                 .mode           = 0644,
 772                 .proc_handler   = &proc_dointvec_minmax,
 773                 .strategy       = &sysctl_intvec,
 774                 .extra1         = &zero,
 775                 .extra2         = &one_hundred,
 776         },
 777 #ifdef CONFIG_HUGETLB_PAGE
 778          {
 779                 .ctl_name       = VM_HUGETLB_PAGES,
 780                 .procname       = "nr_hugepages",
 781                 .data           = &max_huge_pages,
 782                 .maxlen         = sizeof(unsigned long),
 783                 .mode           = 0644,
 784                 .proc_handler   = &hugetlb_sysctl_handler,
 785                 .extra1         = (void *)&hugetlb_zero,
 786                 .extra2         = (void *)&hugetlb_infinity,
 787          },
 788          {
 789                 .ctl_name       = VM_HUGETLB_GROUP,
 790                 .procname       = "hugetlb_shm_group",
 791                 .data           = &sysctl_hugetlb_shm_group,
 792                 .maxlen         = sizeof(gid_t),
 793                 .mode           = 0644,
 794                 .proc_handler   = &proc_dointvec,
 795          },
 796 #endif
 797         {
 798                 .ctl_name       = VM_LOWMEM_RESERVE_RATIO,
 799                 .procname       = "lowmem_reserve_ratio",
 800                 .data           = &sysctl_lowmem_reserve_ratio,
 801                 .maxlen         = sizeof(sysctl_lowmem_reserve_ratio),
 802                 .mode           = 0644,
 803                 .proc_handler   = &lowmem_reserve_ratio_sysctl_handler,
 804                 .strategy       = &sysctl_intvec,
 805         },
 806         {
 807                 .ctl_name       = VM_DROP_PAGECACHE,
 808                 .procname       = "drop_caches",
 809                 .data           = &sysctl_drop_caches,
 810                 .maxlen         = sizeof(int),
 811                 .mode           = 0644,
 812                 .proc_handler   = drop_caches_sysctl_handler,
 813                 .strategy       = &sysctl_intvec,
 814         },
 815         {
 816                 .ctl_name       = VM_MIN_FREE_KBYTES,
 817                 .procname       = "min_free_kbytes",
 818                 .data           = &min_free_kbytes,
 819                 .maxlen         = sizeof(min_free_kbytes),
 820                 .mode           = 0644,
 821                 .proc_handler   = &min_free_kbytes_sysctl_handler,
 822                 .strategy       = &sysctl_intvec,
 823                 .extra1         = &zero,
 824         },
 825         {
 826                 .ctl_name       = VM_PERCPU_PAGELIST_FRACTION,
 827                 .procname       = "percpu_pagelist_fraction",
 828                 .data           = &percpu_pagelist_fraction,
 829                 .maxlen         = sizeof(percpu_pagelist_fraction),
 830                 .mode           = 0644,
 831                 .proc_handler   = &percpu_pagelist_fraction_sysctl_handler,
 832                 .strategy       = &sysctl_intvec,
 833                 .extra1         = &min_percpu_pagelist_fract,
 834         },
 835 #ifdef CONFIG_MMU
 836         {
 837                 .ctl_name       = VM_MAX_MAP_COUNT,
 838                 .procname       = "max_map_count",
 839                 .data           = &sysctl_max_map_count,
 840                 .maxlen         = sizeof(sysctl_max_map_count),
 841                 .mode           = 0644,
 842                 .proc_handler   = &proc_dointvec
 843         },
 844 #endif
 845         {
 846                 .ctl_name       = VM_LAPTOP_MODE,
 847                 .procname       = "laptop_mode",
 848                 .data           = &laptop_mode,
 849                 .maxlen         = sizeof(laptop_mode),
 850                 .mode           = 0644,
 851                 .proc_handler   = &proc_dointvec,
 852                 .strategy       = &sysctl_intvec,
 853                 .extra1         = &zero,
 854         },
 855         {
 856                 .ctl_name       = VM_BLOCK_DUMP,
 857                 .procname       = "block_dump",
 858                 .data           = &block_dump,
 859                 .maxlen         = sizeof(block_dump),
 860                 .mode           = 0644,
 861                 .proc_handler   = &proc_dointvec,
 862                 .strategy       = &sysctl_intvec,
 863                 .extra1         = &zero,
 864         },
 865         {
 866                 .ctl_name       = VM_VFS_CACHE_PRESSURE,
 867                 .procname       = "vfs_cache_pressure",
 868                 .data           = &sysctl_vfs_cache_pressure,
 869                 .maxlen         = sizeof(sysctl_vfs_cache_pressure),
 870                 .mode           = 0644,
 871                 .proc_handler   = &proc_dointvec,
 872                 .strategy       = &sysctl_intvec,
 873                 .extra1         = &zero,
 874         },
 875 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 876         {
 877                 .ctl_name       = VM_LEGACY_VA_LAYOUT,
 878                 .procname       = "legacy_va_layout",
 879                 .data           = &sysctl_legacy_va_layout,
 880                 .maxlen         = sizeof(sysctl_legacy_va_layout),
 881                 .mode           = 0644,
 882                 .proc_handler   = &proc_dointvec,
 883                 .strategy       = &sysctl_intvec,
 884                 .extra1         = &zero,
 885         },
 886 #endif
 887 #ifdef CONFIG_SWAP
 888         {
 889                 .ctl_name       = VM_SWAP_TOKEN_TIMEOUT,
 890                 .procname       = "swap_token_timeout",
 891                 .data           = &swap_token_default_timeout,
 892                 .maxlen         = sizeof(swap_token_default_timeout),
 893                 .mode           = 0644,
 894                 .proc_handler   = &proc_dointvec_jiffies,
 895                 .strategy       = &sysctl_jiffies,
 896         },
 897 #endif
 898 #ifdef CONFIG_NUMA
 899         {
 900                 .ctl_name       = VM_ZONE_RECLAIM_MODE,
 901                 .procname       = "zone_reclaim_mode",
 902                 .data           = &zone_reclaim_mode,
 903                 .maxlen         = sizeof(zone_reclaim_mode),
 904                 .mode           = 0644,
 905                 .proc_handler   = &proc_dointvec,
 906                 .strategy       = &sysctl_intvec,
 907                 .extra1         = &zero,
 908         },
 909         {
 910                 .ctl_name       = VM_ZONE_RECLAIM_INTERVAL,
 911                 .procname       = "zone_reclaim_interval",
 912                 .data           = &zone_reclaim_interval,
 913                 .maxlen         = sizeof(zone_reclaim_interval),
 914                 .mode           = 0644,
 915                 .proc_handler   = &proc_dointvec_jiffies,
 916                 .strategy       = &sysctl_jiffies,
 917         },
 918 #endif
 919         { .ctl_name = 0 }
 920 };
 921
 922 static ctl_table proc_table[] = {
 923         { .ctl_name = 0 }
 924 };
 925
 926 static ctl_table fs_table[] = {
 927         {
 928                 .ctl_name       = FS_NRINODE,
 929                 .procname       = "inode-nr",
 930                 .data           = &inodes_stat,
 931                 .maxlen         = 2*sizeof(int),
 932                 .mode           = 0444,
 933                 .proc_handler   = &proc_dointvec,
 934         },
 935         {
 936                 .ctl_name       = FS_STATINODE,
 937                 .procname       = "inode-state",
 938                 .data           = &inodes_stat,
 939                 .maxlen         = 7*sizeof(int),
 940                 .mode           = 0444,
 941                 .proc_handler   = &proc_dointvec,
 942         },
 943         {
 944                 .ctl_name       = FS_NRFILE,
 945                 .procname       = "file-nr",
 946                 .data           = &files_stat,
 947                 .maxlen         = 3*sizeof(int),
 948                 .mode           = 0444,
 949                 .proc_handler   = &proc_nr_files,
 950         },
 951         {
 952                 .ctl_name       = FS_MAXFILE,
 953                 .procname       = "file-max",
 954                 .data           = &files_stat.max_files,
 955                 .maxlen         = sizeof(int),
 956                 .mode           = 0644,
 957                 .proc_handler   = &proc_dointvec,
 958         },
 959         {
 960                 .ctl_name       = FS_DENTRY,
 961                 .procname       = "dentry-state",
 962                 .data           = &dentry_stat,
 963                 .maxlen         = 6*sizeof(int),
 964                 .mode           = 0444,
 965                 .proc_handler   = &proc_dointvec,
 966         },
 967         {
 968                 .ctl_name       = FS_OVERFLOWUID,
 969                 .procname       = "overflowuid",
 970                 .data           = &fs_overflowuid,
 971                 .maxlen         = sizeof(int),
 972                 .mode           = 0644,
 973                 .proc_handler   = &proc_dointvec_minmax,
 974                 .strategy       = &sysctl_intvec,
 975                 .extra1         = &minolduid,
 976                 .extra2         = &maxolduid,
 977         },
 978         {
 979                 .ctl_name       = FS_OVERFLOWGID,
 980                 .procname       = "overflowgid",
 981                 .data           = &fs_overflowgid,
 982                 .maxlen         = sizeof(int),
 983                 .mode           = 0644,
 984                 .proc_handler   = &proc_dointvec_minmax,
 985                 .strategy       = &sysctl_intvec,
 986                 .extra1         = &minolduid,
 987                 .extra2         = &maxolduid,
 988         },
 989         {
 990                 .ctl_name       = FS_LEASES,
 991                 .procname       = "leases-enable",
 992                 .data           = &leases_enable,
 993                 .maxlen         = sizeof(int),
 994                 .mode           = 0644,
 995                 .proc_handler   = &proc_dointvec,
 996         },
 997 #ifdef CONFIG_DNOTIFY
 998         {
 999                 .ctl_name       = FS_DIR_NOTIFY,
1000                 .procname       = "dir-notify-enable",
1001                 .data           = &dir_notify_enable,
1002                 .maxlen         = sizeof(int),
1003                 .mode           = 0644,
1004                 .proc_handler   = &proc_dointvec,
1005         },
1006 #endif
1007 #ifdef CONFIG_MMU
1008         {
1009                 .ctl_name       = FS_LEASE_TIME,
1010                 .procname       = "lease-break-time",
1011                 .data           = &lease_break_time,
1012                 .maxlen         = sizeof(int),
1013                 .mode           = 0644,
1014                 .proc_handler   = &proc_dointvec,
1015         },
1016         {
1017                 .ctl_name       = FS_AIO_NR,
1018                 .procname       = "aio-nr",
1019                 .data           = &aio_nr,
1020                 .maxlen         = sizeof(aio_nr),
1021                 .mode           = 0444,
1022                 .proc_handler   = &proc_doulongvec_minmax,
1023         },
1024         {
1025                 .ctl_name       = FS_AIO_MAX_NR,
1026                 .procname       = "aio-max-nr",
1027                 .data           = &aio_max_nr,
1028                 .maxlen         = sizeof(aio_max_nr),
1029                 .mode           = 0644,
1030                 .proc_handler   = &proc_doulongvec_minmax,
1031         },
1032 #ifdef CONFIG_INOTIFY
1033         {
1034                 .ctl_name       = FS_INOTIFY,
1035                 .procname       = "inotify",
1036                 .mode           = 0555,
1037                 .child          = inotify_table,
1038         },
1039 #endif
1040 #endif
1041         {
1042                 .ctl_name       = KERN_SETUID_DUMPABLE,
1043                 .procname       = "suid_dumpable",
1044                 .data           = &suid_dumpable,
1045                 .maxlen         = sizeof(int),
1046                 .mode           = 0644,
1047                 .proc_handler   = &proc_dointvec,
1048         },
1049         { .ctl_name = 0 }
1050 };
1051
1052 static ctl_table debug_table[] = {
1053         { .ctl_name = 0 }
1054 };
1055
1056 static ctl_table dev_table[] = {
1057         { .ctl_name = 0 }
1058 };
1059
1060 extern void init_irq_proc (void);
1061
1062 static DEFINE_SPINLOCK(sysctl_lock);
1063
1064 /* called under sysctl_lock */
1065 static int use_table(struct ctl_table_header *p)
1066 {
1067         if (unlikely(p->unregistering))
1068                 return 0;
1069         p->used++;
1070         return 1;
1071 }
1072
1073 /* called under sysctl_lock */
1074 static void unuse_table(struct ctl_table_header *p)
1075 {
1076         if (!--p->used)
1077                 if (unlikely(p->unregistering))
1078                         complete(p->unregistering);
1079 }
1080
1081 /* called under sysctl_lock, will reacquire if has to wait */
1082 static void start_unregistering(struct ctl_table_header *p)
1083 {
1084         /*
1085          * if p->used is 0, nobody will ever touch that entry again;
1086          * we'll eliminate all paths to it before dropping sysctl_lock
1087          */
1088         if (unlikely(p->used)) {
1089                 struct completion wait;
1090                 init_completion(&wait);
1091                 p->unregistering = &wait;
1092                 spin_unlock(&sysctl_lock);
1093                 wait_for_completion(&wait);
1094                 spin_lock(&sysctl_lock);
1095         }
1096         /*
1097          * do not remove from the list until nobody holds it; walking the
1098          * list in do_sysctl() relies on that.
1099          */
1100         list_del_init(&p->ctl_entry);
1101 }
1102
1103 void __init sysctl_init(void)
1104 {
1105 #ifdef CONFIG_PROC_FS
1106         register_proc_table(root_table, proc_sys_root, &root_table_header);
1107         init_irq_proc();
1108 #endif
1109 }
1110
1111 int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
1112                void __user *newval, size_t newlen)
1113 {
1114         struct list_head *tmp;
1115         int error = -ENOTDIR;
1116
1117         if (nlen <= 0 || nlen >= CTL_MAXNAME)
1118                 return -ENOTDIR;
1119         if (oldval) {
1120                 int old_len;
1121                 if (!oldlenp || get_user(old_len, oldlenp))
1122                         return -EFAULT;
1123         }
1124         spin_lock(&sysctl_lock);
1125         tmp = &root_table_header.ctl_entry;
1126         do {
1127                 struct ctl_table_header *head =
1128                         list_entry(tmp, struct ctl_table_header, ctl_entry);
1129                 void *context = NULL;
1130
1131                 if (!use_table(head))
1132                         continue;
1133
1134                 spin_unlock(&sysctl_lock);
1135
1136                 error = parse_table(name, nlen, oldval, oldlenp,
1137                                         newval, newlen, head->ctl_table,
1138                                         &context);
1139                 kfree(context);
1140
1141                 spin_lock(&sysctl_lock);
1142                 unuse_table(head);
1143                 if (error != -ENOTDIR)
1144                         break;
1145         } while ((tmp = tmp->next) != &root_table_header.ctl_entry);
1146         spin_unlock(&sysctl_lock);
1147         return error;
1148 }
1149
1150 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
1151 {
1152         struct __sysctl_args tmp;
1153         int error;
1154
1155         if (copy_from_user(&tmp, args, sizeof(tmp)))
1156                 return -EFAULT;
1157
1158         lock_kernel();
1159         error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
1160                           tmp.newval, tmp.newlen);
1161         unlock_kernel();
1162         return error;
1163 }
1164
1165 /*
1166  * ctl_perm does NOT grant the superuser all rights automatically, because
1167  * some sysctl variables are readonly even to root.
1168  */
1169
1170 static int test_perm(int mode, int op)
1171 {
1172         if (!current->euid)
1173                 mode >>= 6;
1174         else if (in_egroup_p(0))
1175                 mode >>= 3;
1176         if ((mode & op & 0007) == op)
1177                 return 0;
1178         return -EACCES;
1179 }
1180
1181 static inline int ctl_perm(ctl_table *table, int op)
1182 {
1183         int error;
1184         error = security_sysctl(table, op);
1185         if (error)
1186                 return error;
1187         return test_perm(table->mode, op);
1188 }
1189
1190 static int parse_table(int __user *name, int nlen,
1191                        void __user *oldval, size_t __user *oldlenp,
1192                        void __user *newval, size_t newlen,
1193                        ctl_table *table, void **context)
1194 {
1195         int n;
1196 repeat:
1197         if (!nlen)
1198                 return -ENOTDIR;
1199         if (get_user(n, name))
1200                 return -EFAULT;
1201         for ( ; table->ctl_name; table++) {
1202                 if (n == table->ctl_name || table->ctl_name == CTL_ANY) {
1203                         int error;
1204                         if (table->child) {
1205                                 if (ctl_perm(table, 001))
1206                                         return -EPERM;
1207                                 if (table->strategy) {
1208                                         error = table->strategy(
1209                                                 table, name, nlen,
1210                                                 oldval, oldlenp,
1211                                                 newval, newlen, context);
1212                                         if (error)
1213                                                 return error;
1214                                 }
1215                                 name++;
1216                                 nlen--;
1217                                 table = table->child;
1218                                 goto repeat;
1219                         }
1220                         error = do_sysctl_strategy(table, name, nlen,
1221                                                    oldval, oldlenp,
1222                                                    newval, newlen, context);
1223                         return error;
1224                 }
1225         }
1226         return -ENOTDIR;
1227 }
1228
1229 /* Perform the actual read/write of a sysctl table entry. */
1230 int do_sysctl_strategy (ctl_table *table,
1231                         int __user *name, int nlen,
1232                         void __user *oldval, size_t __user *oldlenp,
1233                         void __user *newval, size_t newlen, void **context)
1234 {
1235         int op = 0, rc;
1236         size_t len;
1237
1238         if (oldval)
1239                 op |= 004;
1240         if (newval)
1241                 op |= 002;
1242         if (ctl_perm(table, op))
1243                 return -EPERM;
1244
1245         if (table->strategy) {
1246                 rc = table->strategy(table, name, nlen, oldval, oldlenp,
1247                                      newval, newlen, context);
1248                 if (rc < 0)
1249                         return rc;
1250                 if (rc > 0)
1251                         return 0;
1252         }
1253
1254         /* If there is no strategy routine, or if the strategy returns
1255          * zero, proceed with automatic r/w */
1256         if (table->data && table->maxlen) {
1257                 if (oldval && oldlenp) {
1258                         if (get_user(len, oldlenp))
1259                                 return -EFAULT;
1260                         if (len) {
1261                                 if (len > table->maxlen)
1262                                         len = table->maxlen;
1263                                 if(copy_to_user(oldval, table->data, len))
1264                                         return -EFAULT;
1265                                 if(put_user(len, oldlenp))
1266                                         return -EFAULT;
1267                         }
1268                 }
1269                 if (newval && newlen) {
1270                         len = newlen;
1271                         if (len > table->maxlen)
1272                                 len = table->maxlen;
1273                         if(copy_from_user(table->data, newval, len))
1274                                 return -EFAULT;
1275                 }
1276         }
1277         return 0;
1278 }
1279
1280 /**
1281  * register_sysctl_table - register a sysctl hierarchy
1282  * @table: the top-level table structure
1283  * @insert_at_head: whether the entry should be inserted in front or at the end
1284  *
1285  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1286  * array. An entry with a ctl_name of 0 terminates the table.
1287  *
1288  * The members of the &ctl_table structure are used as follows:
1289  *
1290  * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
1291  *            must be unique within that level of sysctl
1292  *
1293  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1294  *            enter a sysctl file
1295  *
1296  * data - a pointer to data for use by proc_handler
1297  *
1298  * maxlen - the maximum size in bytes of the data
1299  *
1300  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1301  *
1302  * child - a pointer to the child sysctl table if this entry is a directory, or
1303  *         %NULL.
1304  *
1305  * proc_handler - the text handler routine (described below)
1306  *
1307  * strategy - the strategy routine (described below)
1308  *
1309  * de - for internal use by the sysctl routines
1310  *
1311  * extra1, extra2 - extra pointers usable by the proc handler routines
1312  *
1313  * Leaf nodes in the sysctl tree will be represented by a single file
1314  * under /proc; non-leaf nodes will be represented by directories.
1315  *
1316  * sysctl(2) can automatically manage read and write requests through
1317  * the sysctl table.  The data and maxlen fields of the ctl_table
1318  * struct enable minimal validation of the values being written to be
1319  * performed, and the mode field allows minimal authentication.
1320  *
1321  * More sophisticated management can be enabled by the provision of a
1322  * strategy routine with the table entry.  This will be called before
1323  * any automatic read or write of the data is performed.
1324  *
1325  * The strategy routine may return
1326  *
1327  * < 0 - Error occurred (error is passed to user process)
1328  *
1329  * 0   - OK - proceed with automatic read or write.
1330  *
1331  * > 0 - OK - read or write has been done by the strategy routine, so
1332  *       return immediately.
1333  *
1334  * There must be a proc_handler routine for any terminal nodes
1335  * mirrored under /proc/sys (non-terminals are handled by a built-in
1336  * directory handler).  Several default handlers are available to
1337  * cover common cases -
1338  *
1339  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1340  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1341  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1342  *
1343  * It is the handler's job to read the input buffer from user memory
1344  * and process it. The handler should return 0 on success.
1345  *
1346  * This routine returns %NULL on a failure to register, and a pointer
1347  * to the table header on success.
1348  */
1349 struct ctl_table_header *register_sysctl_table(ctl_table * table,
1350                                                int insert_at_head)
1351 {
1352         struct ctl_table_header *tmp;
1353         tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
1354         if (!tmp)
1355                 return NULL;
1356         tmp->ctl_table = table;
1357         INIT_LIST_HEAD(&tmp->ctl_entry);
1358         tmp->used = 0;
1359         tmp->unregistering = NULL;
1360         spin_lock(&sysctl_lock);
1361         if (insert_at_head)
1362                 list_add(&tmp->ctl_entry, &root_table_header.ctl_entry);
1363         else
1364                 list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
1365         spin_unlock(&sysctl_lock);
1366 #ifdef CONFIG_PROC_FS
1367         register_proc_table(table, proc_sys_root, tmp);
1368 #endif
1369         return tmp;
1370 }
1371
1372 /**
1373  * unregister_sysctl_table - unregister a sysctl table hierarchy
1374  * @header: the header returned from register_sysctl_table
1375  *
1376  * Unregisters the sysctl table and all children. proc entries may not
1377  * actually be removed until they are no longer used by anyone.
1378  */
1379 void unregister_sysctl_table(struct ctl_table_header * header)
1380 {
1381         might_sleep();
1382         spin_lock(&sysctl_lock);
1383         start_unregistering(header);
1384 #ifdef CONFIG_PROC_FS
1385         unregister_proc_table(header->ctl_table, proc_sys_root);
1386 #endif
1387         spin_unlock(&sysctl_lock);
1388         kfree(header);
1389 }
1390
1391 /*
1392  * /proc/sys support
1393  */
1394
1395 #ifdef CONFIG_PROC_FS
1396
1397 /* Scan the sysctl entries in table and add them all into /proc */
1398 static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
1399 {
1400         struct proc_dir_entry *de;
1401         int len;
1402         mode_t mode;
1403
1404         for (; table->ctl_name; table++) {
1405                 /* Can't do anything without a proc name. */
1406                 if (!table->procname)
1407                         continue;
1408                 /* Maybe we can't do anything with it... */
1409                 if (!table->proc_handler && !table->child) {
1410                         printk(KERN_WARNING "SYSCTL: Can't register %s\n",
1411                                 table->procname);
1412                         continue;
1413                 }
1414
1415                 len = strlen(table->procname);
1416                 mode = table->mode;
1417
1418                 de = NULL;
1419                 if (table->proc_handler)
1420                         mode |= S_IFREG;
1421                 else {
1422                         mode |= S_IFDIR;
1423                         for (de = root->subdir; de; de = de->next) {
1424                                 if (proc_match(len, table->procname, de))
1425                                         break;
1426                         }
1427                         /* If the subdir exists already, de is non-NULL */
1428                 }
1429
1430                 if (!de) {
1431                         de = create_proc_entry(table->procname, mode, root);
1432                         if (!de)
1433                                 continue;
1434                         de->set = set;
1435                         de->data = (void *) table;
1436                         if (table->proc_handler)
1437                                 de->proc_fops = &proc_sys_file_operations;
1438                 }
1439                 table->de = de;
1440                 if (de->mode & S_IFDIR)
1441                         register_proc_table(table->child, de, set);
1442         }
1443 }
1444
1445 /*
1446  * Unregister a /proc sysctl table and any subdirectories.
1447  */
1448 static void unregister_proc_table(ctl_table * table, struct proc_dir_entry *root)
1449 {
1450         struct proc_dir_entry *de;
1451         for (; table->ctl_name; table++) {
1452                 if (!(de = table->de))
1453                         continue;
1454                 if (de->mode & S_IFDIR) {
1455                         if (!table->child) {
1456                                 printk (KERN_ALERT "Help - malformed sysctl tree on free\n");
1457                                 continue;
1458                         }
1459                         unregister_proc_table(table->child, de);
1460
1461                         /* Don't unregister directories which still have entries.. */
1462                         if (de->subdir)
1463                                 continue;
1464                 }
1465
1466                 /*
1467                  * In any case, mark the entry as goner; we'll keep it
1468                  * around if it's busy, but we'll know to do nothing with
1469                  * its fields.  We are under sysctl_lock here.
1470                  */
1471                 de->data = NULL;
1472
1473                 /* Don't unregister proc entries that are still being used.. */
1474                 if (atomic_read(&de->count))
1475                         continue;
1476
1477                 table->de = NULL;
1478                 remove_proc_entry(table->procname, root);
1479         }
1480 }
1481
1482 static ssize_t do_rw_proc(int write, struct file * file, char __user * buf,
1483                           size_t count, loff_t *ppos)
1484 {
1485         int op;
1486         struct proc_dir_entry *de = PDE(file->f_dentry->d_inode);
1487         struct ctl_table *table;
1488         size_t res;
1489         ssize_t error = -ENOTDIR;
1490
1491         spin_lock(&sysctl_lock);
1492         if (de && de->data && use_table(de->set)) {
1493                 /*
1494                  * at that point we know that sysctl was not unregistered
1495                  * and won't be until we finish
1496                  */
1497                 spin_unlock(&sysctl_lock);
1498                 table = (struct ctl_table *) de->data;
1499                 if (!table || !table->proc_handler)
1500                         goto out;
1501                 error = -EPERM;
1502                 op = (write ? 002 : 004);
1503                 if (ctl_perm(table, op))
1504                         goto out;
1505
1506                 /* careful: calling conventions are nasty here */
1507                 res = count;
1508                 error = (*table->proc_handler)(table, write, file,
1509                                                 buf, &res, ppos);
1510                 if (!error)
1511                         error = res;
1512         out:
1513                 spin_lock(&sysctl_lock);
1514                 unuse_table(de->set);
1515         }
1516         spin_unlock(&sysctl_lock);
1517         return error;
1518 }
1519
1520 static int proc_opensys(struct inode *inode, struct file *file)
1521 {
1522         if (file->f_mode & FMODE_WRITE) {
1523                 /*
1524                  * sysctl entries that are not writable,
1525                  * are _NOT_ writable, capabilities or not.
1526                  */
1527                 if (!(inode->i_mode & S_IWUSR))
1528                         return -EPERM;
1529         }
1530
1531         return 0;
1532 }
1533
1534 static ssize_t proc_readsys(struct file * file, char __user * buf,
1535                             size_t count, loff_t *ppos)
1536 {
1537         return do_rw_proc(0, file, buf, count, ppos);
1538 }
1539
1540 static ssize_t proc_writesys(struct file * file, const char __user * buf,
1541                              size_t count, loff_t *ppos)
1542 {
1543         return do_rw_proc(1, file, (char __user *) buf, count, ppos);
1544 }
1545
1546 /**
1547  * proc_dostring - read a string sysctl
1548  * @table: the sysctl table
1549  * @write: %TRUE if this is a write to the sysctl file
1550  * @filp: the file structure
1551  * @buffer: the user buffer
1552  * @lenp: the size of the user buffer
1553  * @ppos: file position
1554  *
1555  * Reads/writes a string from/to the user buffer. If the kernel
1556  * buffer provided is not large enough to hold the string, the
1557  * string is truncated. The copied string is %NULL-terminated.
1558  * If the string is being read by the user process, it is copied
1559  * and a newline '\n' is added. It is truncated if the buffer is
1560  * not large enough.
1561  *
1562  * Returns 0 on success.
1563  */
1564 int proc_dostring(ctl_table *table, int write, struct file *filp,
1565                   void __user *buffer, size_t *lenp, loff_t *ppos)
1566 {
1567         size_t len;
1568         char __user *p;
1569         char c;
1570
1571         if (!table->data || !table->maxlen || !*lenp ||
1572             (*ppos && !write)) {
1573                 *lenp = 0;
1574                 return 0;
1575         }
1576
1577         if (write) {
1578                 len = 0;
1579                 p = buffer;
1580                 while (len < *lenp) {
1581                         if (get_user(c, p++))
1582                                 return -EFAULT;
1583                         if (c == 0 || c == '\n')
1584                                 break;
1585                         len++;
1586                 }
1587                 if (len >= table->maxlen)
1588                         len = table->maxlen-1;
1589                 if(copy_from_user(table->data, buffer, len))
1590                         return -EFAULT;
1591                 ((char *) table->data)[len] = 0;
1592                 *ppos += *lenp;
1593         } else {
1594                 len = strlen(table->data);
1595                 if (len > table->maxlen)
1596                         len = table->maxlen;
1597                 if (len > *lenp)
1598                         len = *lenp;
1599                 if (len)
1600                         if(copy_to_user(buffer, table->data, len))
1601                                 return -EFAULT;
1602                 if (len < *lenp) {
1603                         if(put_user('\n', ((char __user *) buffer) + len))
1604                                 return -EFAULT;
1605                         len++;
1606                 }
1607                 *lenp = len;
1608                 *ppos += len;
1609         }
1610         return 0;
1611 }
1612
1613 /*
1614  *      Special case of dostring for the UTS structure. This has locks
1615  *      to observe. Should this be in kernel/sys.c ????
1616  */
1617
1618 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
1619                   void __user *buffer, size_t *lenp, loff_t *ppos)
1620 {
1621         int r;
1622
1623         if (!write) {
1624                 down_read(&uts_sem);
1625                 r=proc_dostring(table,0,filp,buffer,lenp, ppos);
1626                 up_read(&uts_sem);
1627         } else {
1628                 down_write(&uts_sem);
1629                 r=proc_dostring(table,1,filp,buffer,lenp, ppos);
1630                 up_write(&uts_sem);
1631         }
1632         return r;
1633 }
1634
1635 static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
1636                                  int *valp,
1637                                  int write, void *data)
1638 {
1639         if (write) {
1640                 *valp = *negp ? -*lvalp : *lvalp;
1641         } else {
1642                 int val = *valp;
1643                 if (val < 0) {
1644                         *negp = -1;
1645                         *lvalp = (unsigned long)-val;
1646                 } else {
1647                         *negp = 0;
1648                         *lvalp = (unsigned long)val;
1649                 }
1650         }
1651         return 0;
1652 }
1653
1654 static int do_proc_dointvec(ctl_table *table, int write, struct file *filp,
1655                   void __user *buffer, size_t *lenp, loff_t *ppos,
1656                   int (*conv)(int *negp, unsigned long *lvalp, int *valp,
1657                               int write, void *data),
1658                   void *data)
1659 {
1660 #define TMPBUFLEN 21
1661         int *i, vleft, first=1, neg, val;
1662         unsigned long lval;
1663         size_t left, len;
1664
1665         char buf[TMPBUFLEN], *p;
1666         char __user *s = buffer;
1667
1668         if (!table->data || !table->maxlen || !*lenp ||
1669             (*ppos && !write)) {
1670                 *lenp = 0;
1671                 return 0;
1672         }
1673
1674         i = (int *) table->data;
1675         vleft = table->maxlen / sizeof(*i);
1676         left = *lenp;
1677
1678         if (!conv)
1679                 conv = do_proc_dointvec_conv;
1680
1681         for (; left && vleft--; i++, first=0) {
1682                 if (write) {
1683                         while (left) {
1684                                 char c;
1685                                 if (get_user(c, s))
1686                                         return -EFAULT;
1687                                 if (!isspace(c))
1688                                         break;
1689                                 left--;
1690                                 s++;
1691                         }
1692                         if (!left)
1693                                 break;
1694                         neg = 0;
1695                         len = left;
1696                         if (len > sizeof(buf) - 1)
1697                                 len = sizeof(buf) - 1;
1698                         if (copy_from_user(buf, s, len))
1699                                 return -EFAULT;
1700                         buf[len] = 0;
1701                         p = buf;
1702                         if (*p == '-' && left > 1) {
1703                                 neg = 1;
1704                                 left--, p++;
1705                         }
1706                         if (*p < '0' || *p > '9')
1707                                 break;
1708
1709                         lval = simple_strtoul(p, &p, 0);
1710
1711                         len = p-buf;
1712                         if ((len < left) && *p && !isspace(*p))
1713                                 break;
1714                         if (neg)
1715                                 val = -val;
1716                         s += len;
1717                         left -= len;
1718
1719                         if (conv(&neg, &lval, i, 1, data))
1720                                 break;
1721                 } else {
1722                         p = buf;
1723                         if (!first)
1724                                 *p++ = '\t';
1725
1726                         if (conv(&neg, &lval, i, 0, data))
1727                                 break;
1728
1729                         sprintf(p, "%s%lu", neg ? "-" : "", lval);
1730                         len = strlen(buf);
1731                         if (len > left)
1732                                 len = left;
1733                         if(copy_to_user(s, buf, len))
1734                                 return -EFAULT;
1735                         left -= len;
1736                         s += len;
1737                 }
1738         }
1739
1740         if (!write && !first && left) {
1741                 if(put_user('\n', s))
1742                         return -EFAULT;
1743                 left--, s++;
1744         }
1745         if (write) {
1746                 while (left) {
1747                         char c;
1748                         if (get_user(c, s++))
1749                                 return -EFAULT;
1750                         if (!isspace(c))
1751                                 break;
1752                         left--;
1753                 }
1754         }
1755         if (write && first)
1756                 return -EINVAL;
1757         *lenp -= left;
1758         *ppos += *lenp;
1759         return 0;
1760 #undef TMPBUFLEN
1761 }
1762
1763 /**
1764  * proc_dointvec - read a vector of integers
1765  * @table: the sysctl table
1766  * @write: %TRUE if this is a write to the sysctl file
1767  * @filp: the file structure
1768  * @buffer: the user buffer
1769  * @lenp: the size of the user buffer
1770  * @ppos: file position
1771  *
1772  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1773  * values from/to the user buffer, treated as an ASCII string.
1774  *
1775  * Returns 0 on success.
1776  */
1777 int proc_dointvec(ctl_table *table, int write, struct file *filp,
1778                      void __user *buffer, size_t *lenp, loff_t *ppos)
1779 {
1780     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1781                             NULL,NULL);
1782 }
1783
1784 #define OP_SET  0
1785 #define OP_AND  1
1786 #define OP_OR   2
1787 #define OP_MAX  3
1788 #define OP_MIN  4
1789
1790 static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp,
1791                                       int *valp,
1792                                       int write, void *data)
1793 {
1794         int op = *(int *)data;
1795         if (write) {
1796                 int val = *negp ? -*lvalp : *lvalp;
1797                 switch(op) {
1798                 case OP_SET:    *valp = val; break;
1799                 case OP_AND:    *valp &= val; break;
1800                 case OP_OR:     *valp |= val; break;
1801                 case OP_MAX:    if(*valp < val)
1802                                         *valp = val;
1803                                 break;
1804                 case OP_MIN:    if(*valp > val)
1805                                 *valp = val;
1806                                 break;
1807                 }
1808         } else {
1809                 int val = *valp;
1810                 if (val < 0) {
1811                         *negp = -1;
1812                         *lvalp = (unsigned long)-val;
1813                 } else {
1814                         *negp = 0;
1815                         *lvalp = (unsigned long)val;
1816                 }
1817         }
1818         return 0;
1819 }
1820
1821 /*
1822  *      init may raise the set.
1823  */
1824
1825 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
1826                         void __user *buffer, size_t *lenp, loff_t *ppos)
1827 {
1828         int op;
1829
1830         if (!capable(CAP_SYS_MODULE)) {
1831                 return -EPERM;
1832         }
1833
1834         op = (current->pid == 1) ? OP_SET : OP_AND;
1835         return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1836                                 do_proc_dointvec_bset_conv,&op);
1837 }
1838
1839 struct do_proc_dointvec_minmax_conv_param {
1840         int *min;
1841         int *max;
1842 };
1843
1844 static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp,
1845                                         int *valp,
1846                                         int write, void *data)
1847 {
1848         struct do_proc_dointvec_minmax_conv_param *param = data;
1849         if (write) {
1850                 int val = *negp ? -*lvalp : *lvalp;
1851                 if ((param->min && *param->min > val) ||
1852                     (param->max && *param->max < val))
1853                         return -EINVAL;
1854                 *valp = val;
1855         } else {
1856                 int val = *valp;
1857                 if (val < 0) {
1858                         *negp = -1;
1859                         *lvalp = (unsigned long)-val;
1860                 } else {
1861                         *negp = 0;
1862                         *lvalp = (unsigned long)val;
1863                 }
1864         }
1865         return 0;
1866 }
1867
1868 /**
1869  * proc_dointvec_minmax - read a vector of integers with min/max values
1870  * @table: the sysctl table
1871  * @write: %TRUE if this is a write to the sysctl file
1872  * @filp: the file structure
1873  * @buffer: the user buffer
1874  * @lenp: the size of the user buffer
1875  * @ppos: file position
1876  *
1877  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1878  * values from/to the user buffer, treated as an ASCII string.
1879  *
1880  * This routine will ensure the values are within the range specified by
1881  * table->extra1 (min) and table->extra2 (max).
1882  *
1883  * Returns 0 on success.
1884  */
1885 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
1886                   void __user *buffer, size_t *lenp, loff_t *ppos)
1887 {
1888         struct do_proc_dointvec_minmax_conv_param param = {
1889                 .min = (int *) table->extra1,
1890                 .max = (int *) table->extra2,
1891         };
1892         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
1893                                 do_proc_dointvec_minmax_conv, &param);
1894 }
1895
1896 static int do_proc_doulongvec_minmax(ctl_table *table, int write,
1897                                      struct file *filp,
1898                                      void __user *buffer,
1899                                      size_t *lenp, loff_t *ppos,
1900                                      unsigned long convmul,
1901                                      unsigned long convdiv)
1902 {
1903 #define TMPBUFLEN 21
1904         unsigned long *i, *min, *max, val;
1905         int vleft, first=1, neg;
1906         size_t len, left;
1907         char buf[TMPBUFLEN], *p;
1908         char __user *s = buffer;
1909
1910         if (!table->data || !table->maxlen || !*lenp ||
1911             (*ppos && !write)) {
1912                 *lenp = 0;
1913                 return 0;
1914         }
1915
1916         i = (unsigned long *) table->data;
1917         min = (unsigned long *) table->extra1;
1918         max = (unsigned long *) table->extra2;
1919         vleft = table->maxlen / sizeof(unsigned long);
1920         left = *lenp;
1921
1922         for (; left && vleft--; i++, min++, max++, first=0) {
1923                 if (write) {
1924                         while (left) {
1925                                 char c;
1926                                 if (get_user(c, s))
1927                                         return -EFAULT;
1928                                 if (!isspace(c))
1929                                         break;
1930                                 left--;
1931                                 s++;
1932                         }
1933                         if (!left)
1934                                 break;
1935                         neg = 0;
1936                         len = left;
1937                         if (len > TMPBUFLEN-1)
1938                                 len = TMPBUFLEN-1;
1939                         if (copy_from_user(buf, s, len))
1940                                 return -EFAULT;
1941                         buf[len] = 0;
1942                         p = buf;
1943                         if (*p == '-' && left > 1) {
1944                                 neg = 1;
1945                                 left--, p++;
1946                         }
1947                         if (*p < '0' || *p > '9')
1948                                 break;
1949                         val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
1950                         len = p-buf;
1951                         if ((len < left) && *p && !isspace(*p))
1952                                 break;
1953                         if (neg)
1954                                 val = -val;
1955                         s += len;
1956                         left -= len;
1957
1958                         if(neg)
1959                                 continue;
1960                         if ((min && val < *min) || (max && val > *max))
1961                                 continue;
1962                         *i = val;
1963                 } else {
1964                         p = buf;
1965                         if (!first)
1966                                 *p++ = '\t';
1967                         sprintf(p, "%lu", convdiv * (*i) / convmul);
1968                         len = strlen(buf);
1969                         if (len > left)
1970                                 len = left;
1971                         if(copy_to_user(s, buf, len))
1972                                 return -EFAULT;
1973                         left -= len;
1974                         s += len;
1975                 }
1976         }
1977
1978         if (!write && !first && left) {
1979                 if(put_user('\n', s))
1980                         return -EFAULT;
1981                 left--, s++;
1982         }
1983         if (write) {
1984                 while (left) {
1985                         char c;
1986                         if (get_user(c, s++))
1987                                 return -EFAULT;
1988                         if (!isspace(c))
1989                                 break;
1990                         left--;
1991                 }
1992         }
1993         if (write && first)
1994                 return -EINVAL;
1995         *lenp -= left;
1996         *ppos += *lenp;
1997         return 0;
1998 #undef TMPBUFLEN
1999 }
2000
2001 /**
2002  * proc_doulongvec_minmax - read a vector of long integers with min/max values
2003  * @table: the sysctl table
2004  * @write: %TRUE if this is a write to the sysctl file
2005  * @filp: the file structure
2006  * @buffer: the user buffer
2007  * @lenp: the size of the user buffer
2008  * @ppos: file position
2009  *
2010  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2011  * values from/to the user buffer, treated as an ASCII string.
2012  *
2013  * This routine will ensure the values are within the range specified by
2014  * table->extra1 (min) and table->extra2 (max).
2015  *
2016  * Returns 0 on success.
2017  */
2018 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2019                            void __user *buffer, size_t *lenp, loff_t *ppos)
2020 {
2021     return do_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos, 1l, 1l);
2022 }
2023
2024 /**
2025  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2026  * @table: the sysctl table
2027  * @write: %TRUE if this is a write to the sysctl file
2028  * @filp: the file structure
2029  * @buffer: the user buffer
2030  * @lenp: the size of the user buffer
2031  * @ppos: file position
2032  *
2033  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2034  * values from/to the user buffer, treated as an ASCII string. The values
2035  * are treated as milliseconds, and converted to jiffies when they are stored.
2036  *
2037  * This routine will ensure the values are within the range specified by
2038  * table->extra1 (min) and table->extra2 (max).
2039  *
2040  * Returns 0 on success.
2041  */
2042 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2043                                       struct file *filp,
2044                                       void __user *buffer,
2045                                       size_t *lenp, loff_t *ppos)
2046 {
2047     return do_proc_doulongvec_minmax(table, write, filp, buffer,
2048                                      lenp, ppos, HZ, 1000l);
2049 }
2050
2051
2052 static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
2053                                          int *valp,
2054                                          int write, void *data)
2055 {
2056         if (write) {
2057                 *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2058         } else {
2059                 int val = *valp;
2060                 unsigned long lval;
2061                 if (val < 0) {
2062                         *negp = -1;
2063                         lval = (unsigned long)-val;
2064                 } else {
2065                         *negp = 0;
2066                         lval = (unsigned long)val;
2067                 }
2068                 *lvalp = lval / HZ;
2069         }
2070         return 0;
2071 }
2072
2073 static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
2074                                                 int *valp,
2075                                                 int write, void *data)
2076 {
2077         if (write) {
2078                 *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2079         } else {
2080                 int val = *valp;
2081                 unsigned long lval;
2082                 if (val < 0) {
2083                         *negp = -1;
2084                         lval = (unsigned long)-val;
2085                 } else {
2086                         *negp = 0;
2087                         lval = (unsigned long)val;
2088                 }
2089                 *lvalp = jiffies_to_clock_t(lval);
2090         }
2091         return 0;
2092 }
2093
2094 static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
2095                                             int *valp,
2096                                             int write, void *data)
2097 {
2098         if (write) {
2099                 *valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2100         } else {
2101                 int val = *valp;
2102                 unsigned long lval;
2103                 if (val < 0) {
2104                         *negp = -1;
2105                         lval = (unsigned long)-val;
2106                 } else {
2107                         *negp = 0;
2108                         lval = (unsigned long)val;
2109                 }
2110                 *lvalp = jiffies_to_msecs(lval);
2111         }
2112         return 0;
2113 }
2114
2115 /**
2116  * proc_dointvec_jiffies - read a vector of integers as seconds
2117  * @table: the sysctl table
2118  * @write: %TRUE if this is a write to the sysctl file
2119  * @filp: the file structure
2120  * @buffer: the user buffer
2121  * @lenp: the size of the user buffer
2122  * @ppos: file position
2123  *
2124  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2125  * values from/to the user buffer, treated as an ASCII string.
2126  * The values read are assumed to be in seconds, and are converted into
2127  * jiffies.
2128  *
2129  * Returns 0 on success.
2130  */
2131 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2132                           void __user *buffer, size_t *lenp, loff_t *ppos)
2133 {
2134     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2135                             do_proc_dointvec_jiffies_conv,NULL);
2136 }
2137
2138 /**
2139  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2140  * @table: the sysctl table
2141  * @write: %TRUE if this is a write to the sysctl file
2142  * @filp: the file structure
2143  * @buffer: the user buffer
2144  * @lenp: the size of the user buffer
2145  * @ppos: pointer to the file position
2146  *
2147  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2148  * values from/to the user buffer, treated as an ASCII string.
2149  * The values read are assumed to be in 1/USER_HZ seconds, and
2150  * are converted into jiffies.
2151  *
2152  * Returns 0 on success.
2153  */
2154 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2155                                  void __user *buffer, size_t *lenp, loff_t *ppos)
2156 {
2157     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2158                             do_proc_dointvec_userhz_jiffies_conv,NULL);
2159 }
2160
2161 /**
2162  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2163  * @table: the sysctl table
2164  * @write: %TRUE if this is a write to the sysctl file
2165  * @filp: the file structure
2166  * @buffer: the user buffer
2167  * @lenp: the size of the user buffer
2168  * @ppos: file position
2169  * @ppos: the current position in the file
2170  *
2171  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2172  * values from/to the user buffer, treated as an ASCII string.
2173  * The values read are assumed to be in 1/1000 seconds, and
2174  * are converted into jiffies.
2175  *
2176  * Returns 0 on success.
2177  */
2178 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2179                              void __user *buffer, size_t *lenp, loff_t *ppos)
2180 {
2181         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
2182                                 do_proc_dointvec_ms_jiffies_conv, NULL);
2183 }
2184
2185 #else /* CONFIG_PROC_FS */
2186
2187 int proc_dostring(ctl_table *table, int write, struct file *filp,
2188                   void __user *buffer, size_t *lenp, loff_t *ppos)
2189 {
2190         return -ENOSYS;
2191 }
2192
2193 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
2194                             void __user *buffer, size_t *lenp, loff_t *ppos)
2195 {
2196         return -ENOSYS;
2197 }
2198
2199 int proc_dointvec(ctl_table *table, int write, struct file *filp,
2200                   void __user *buffer, size_t *lenp, loff_t *ppos)
2201 {
2202         return -ENOSYS;
2203 }
2204
2205 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
2206                         void __user *buffer, size_t *lenp, loff_t *ppos)
2207 {
2208         return -ENOSYS;
2209 }
2210
2211 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
2212                     void __user *buffer, size_t *lenp, loff_t *ppos)
2213 {
2214         return -ENOSYS;
2215 }
2216
2217 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2218                     void __user *buffer, size_t *lenp, loff_t *ppos)
2219 {
2220         return -ENOSYS;
2221 }
2222
2223 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2224                     void __user *buffer, size_t *lenp, loff_t *ppos)
2225 {
2226         return -ENOSYS;
2227 }
2228
2229 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2230                              void __user *buffer, size_t *lenp, loff_t *ppos)
2231 {
2232         return -ENOSYS;
2233 }
2234
2235 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2236                     void __user *buffer, size_t *lenp, loff_t *ppos)
2237 {
2238         return -ENOSYS;
2239 }
2240
2241 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2242                                       struct file *filp,
2243                                       void __user *buffer,
2244                                       size_t *lenp, loff_t *ppos)
2245 {
2246     return -ENOSYS;
2247 }
2248
2249
2250 #endif /* CONFIG_PROC_FS */
2251
2252
2253 /*
2254  * General sysctl support routines
2255  */
2256
2257 /* The generic string strategy routine: */
2258 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2259                   void __user *oldval, size_t __user *oldlenp,
2260                   void __user *newval, size_t newlen, void **context)
2261 {
2262         if (!table->data || !table->maxlen)
2263                 return -ENOTDIR;
2264
2265         if (oldval && oldlenp) {
2266                 size_t bufsize;
2267                 if (get_user(bufsize, oldlenp))
2268                         return -EFAULT;
2269                 if (bufsize) {
2270                         size_t len = strlen(table->data), copied;
2271
2272                         /* This shouldn't trigger for a well-formed sysctl */
2273                         if (len > table->maxlen)
2274                                 len = table->maxlen;
2275
2276                         /* Copy up to a max of bufsize-1 bytes of the string */
2277                         copied = (len >= bufsize) ? bufsize - 1 : len;
2278
2279                         if (copy_to_user(oldval, table->data, copied) ||
2280                             put_user(0, (char __user *)(oldval + copied)))
2281                                 return -EFAULT;
2282                         if (put_user(len, oldlenp))
2283                                 return -EFAULT;
2284                 }
2285         }
2286         if (newval && newlen) {
2287                 size_t len = newlen;
2288                 if (len > table->maxlen)
2289                         len = table->maxlen;
2290                 if(copy_from_user(table->data, newval, len))
2291                         return -EFAULT;
2292                 if (len == table->maxlen)
2293                         len--;
2294                 ((char *) table->data)[len] = 0;
2295         }
2296         return 1;
2297 }
2298
2299 /*
2300  * This function makes sure that all of the integers in the vector
2301  * are between the minimum and maximum values given in the arrays
2302  * table->extra1 and table->extra2, respectively.
2303  */
2304 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2305                 void __user *oldval, size_t __user *oldlenp,
2306                 void __user *newval, size_t newlen, void **context)
2307 {
2308
2309         if (newval && newlen) {
2310                 int __user *vec = (int __user *) newval;
2311                 int *min = (int *) table->extra1;
2312                 int *max = (int *) table->extra2;
2313                 size_t length;
2314                 int i;
2315
2316                 if (newlen % sizeof(int) != 0)
2317                         return -EINVAL;
2318
2319                 if (!table->extra1 && !table->extra2)
2320                         return 0;
2321
2322                 if (newlen > table->maxlen)
2323                         newlen = table->maxlen;
2324                 length = newlen / sizeof(int);
2325
2326                 for (i = 0; i < length; i++) {
2327                         int value;
2328                         if (get_user(value, vec + i))
2329                                 return -EFAULT;
2330                         if (min && value < min[i])
2331                                 return -EINVAL;
2332                         if (max && value > max[i])
2333                                 return -EINVAL;
2334                 }
2335         }
2336         return 0;
2337 }
2338
2339 /* Strategy function to convert jiffies to seconds */
2340 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2341                 void __user *oldval, size_t __user *oldlenp,
2342                 void __user *newval, size_t newlen, void **context)
2343 {
2344         if (oldval) {
2345                 size_t olen;
2346                 if (oldlenp) {
2347                         if (get_user(olen, oldlenp))
2348                                 return -EFAULT;
2349                         if (olen!=sizeof(int))
2350                                 return -EINVAL;
2351                 }
2352                 if (put_user(*(int *)(table->data)/HZ, (int __user *)oldval) ||
2353                     (oldlenp && put_user(sizeof(int),oldlenp)))
2354                         return -EFAULT;
2355         }
2356         if (newval && newlen) {
2357                 int new;
2358                 if (newlen != sizeof(int))
2359                         return -EINVAL;
2360                 if (get_user(new, (int __user *)newval))
2361                         return -EFAULT;
2362                 *(int *)(table->data) = new*HZ;
2363         }
2364         return 1;
2365 }
2366
2367 /* Strategy function to convert jiffies to seconds */
2368 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2369                 void __user *oldval, size_t __user *oldlenp,
2370                 void __user *newval, size_t newlen, void **context)
2371 {
2372         if (oldval) {
2373                 size_t olen;
2374                 if (oldlenp) {
2375                         if (get_user(olen, oldlenp))
2376                                 return -EFAULT;
2377                         if (olen!=sizeof(int))
2378                                 return -EINVAL;
2379                 }
2380                 if (put_user(jiffies_to_msecs(*(int *)(table->data)), (int __user *)oldval) ||
2381                     (oldlenp && put_user(sizeof(int),oldlenp)))
2382                         return -EFAULT;
2383         }
2384         if (newval && newlen) {
2385                 int new;
2386                 if (newlen != sizeof(int))
2387                         return -EINVAL;
2388                 if (get_user(new, (int __user *)newval))
2389                         return -EFAULT;
2390                 *(int *)(table->data) = msecs_to_jiffies(new);
2391         }
2392         return 1;
2393 }
2394
2395 #else /* CONFIG_SYSCTL */
2396
2397
2398 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
2399 {
2400         return -ENOSYS;
2401 }
2402
2403 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2404                   void __user *oldval, size_t __user *oldlenp,
2405                   void __user *newval, size_t newlen, void **context)
2406 {
2407         return -ENOSYS;
2408 }
2409
2410 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2411                 void __user *oldval, size_t __user *oldlenp,
2412                 void __user *newval, size_t newlen, void **context)
2413 {
2414         return -ENOSYS;
2415 }
2416
2417 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2418                 void __user *oldval, size_t __user *oldlenp,
2419                 void __user *newval, size_t newlen, void **context)
2420 {
2421         return -ENOSYS;
2422 }
2423
2424 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2425                 void __user *oldval, size_t __user *oldlenp,
2426                 void __user *newval, size_t newlen, void **context)
2427 {
2428         return -ENOSYS;
2429 }
2430
2431 int proc_dostring(ctl_table *table, int write, struct file *filp,
2432                   void __user *buffer, size_t *lenp, loff_t *ppos)
2433 {
2434         return -ENOSYS;
2435 }
2436
2437 int proc_dointvec(ctl_table *table, int write, struct file *filp,
2438                   void __user *buffer, size_t *lenp, loff_t *ppos)
2439 {
2440         return -ENOSYS;
2441 }
2442
2443 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
2444                         void __user *buffer, size_t *lenp, loff_t *ppos)
2445 {
2446         return -ENOSYS;
2447 }
2448
2449 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
2450                     void __user *buffer, size_t *lenp, loff_t *ppos)
2451 {
2452         return -ENOSYS;
2453 }
2454
2455 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2456                           void __user *buffer, size_t *lenp, loff_t *ppos)
2457 {
2458         return -ENOSYS;
2459 }
2460
2461 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2462                           void __user *buffer, size_t *lenp, loff_t *ppos)
2463 {
2464         return -ENOSYS;
2465 }
2466
2467 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2468                              void __user *buffer, size_t *lenp, loff_t *ppos)
2469 {
2470         return -ENOSYS;
2471 }
2472
2473 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2474                     void __user *buffer, size_t *lenp, loff_t *ppos)
2475 {
2476         return -ENOSYS;
2477 }
2478
2479 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2480                                       struct file *filp,
2481                                       void __user *buffer,
2482                                       size_t *lenp, loff_t *ppos)
2483 {
2484     return -ENOSYS;
2485 }
2486
2487 struct ctl_table_header * register_sysctl_table(ctl_table * table,
2488                                                 int insert_at_head)
2489 {
2490         return NULL;
2491 }
2492
2493 void unregister_sysctl_table(struct ctl_table_header * table)
2494 {
2495 }
2496
2497 #endif /* CONFIG_SYSCTL */
2498
2499 /*
2500  * No sense putting this after each symbol definition, twice,
2501  * exception granted :-)
2502  */
2503 EXPORT_SYMBOL(proc_dointvec);
2504 EXPORT_SYMBOL(proc_dointvec_jiffies);
2505 EXPORT_SYMBOL(proc_dointvec_minmax);
2506 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2507 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2508 EXPORT_SYMBOL(proc_dostring);
2509 EXPORT_SYMBOL(proc_doulongvec_minmax);
2510 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2511 EXPORT_SYMBOL(register_sysctl_table);
2512 EXPORT_SYMBOL(sysctl_intvec);
2513 EXPORT_SYMBOL(sysctl_jiffies);
2514 EXPORT_SYMBOL(sysctl_ms_jiffies);
2515 EXPORT_SYMBOL(sysctl_string);
2516 EXPORT_SYMBOL(unregister_sysctl_table);