kernel/sysctl.c

   1 /*
   2  * sysctl.c: General linux system control interface
   3  *
   4  * Begun 24 March 1995, Stephen Tweedie
   5  * Added /proc support, Dec 1995
   6  * Added bdflush entry and intvec min/max checking, 2/23/96, Tom Dyas.
   7  * Added hooks for /proc/sys/net (minor, minor patch), 96/4/1, Mike Shaver.
   8  * Added kernel/java-{interpreter,appletviewer}, 96/5/10, Mike Shaver.
   9  * Dynamic registration fixes, Stephen Tweedie.
  10  * Added kswapd-interval, ctrl-alt-del, printk stuff, 1/8/97, Chris Horn.
  11  * Made sysctl support optional via CONFIG_SYSCTL, 1/10/97, Chris
  12  *  Horn.
  13  * Added proc_doulongvec_ms_jiffies_minmax, 09/08/99, Carlos H. Bauer.
  14  * Added proc_doulongvec_minmax, 09/08/99, Carlos H. Bauer.
  15  * Changed linked lists to use list.h instead of lists.h, 02/24/00, Bill
  16  *  Wendling.
  17  * The list_for_each() macro wasn't appropriate for the sysctl loop.
  18  *  Removed it and replaced it with older style, 03/23/00, Bill Wendling
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/mm.h>
  23 #include <linux/swap.h>
  24 #include <linux/slab.h>
  25 #include <linux/sysctl.h>
  26 #include <linux/proc_fs.h>
  27 #include <linux/capability.h>
  28 #include <linux/ctype.h>
  29 #include <linux/utsname.h>
  30 #include <linux/capability.h>
  31 #include <linux/smp_lock.h>
  32 #include <linux/init.h>
  33 #include <linux/kernel.h>
  34 #include <linux/kobject.h>
  35 #include <linux/net.h>
  36 #include <linux/sysrq.h>
  37 #include <linux/highuid.h>
  38 #include <linux/writeback.h>
  39 #include <linux/hugetlb.h>
  40 #include <linux/security.h>
  41 #include <linux/initrd.h>
  42 #include <linux/times.h>
  43 #include <linux/limits.h>
  44 #include <linux/dcache.h>
  45 #include <linux/syscalls.h>
  46 #include <linux/nfs_fs.h>
  47 #include <linux/acpi.h>
  48
  49 #include <asm/uaccess.h>
  50 #include <asm/processor.h>
  51
  52 extern int proc_nr_files(ctl_table *table, int write, struct file *filp,
  53                      void __user *buffer, size_t *lenp, loff_t *ppos);
  54
  55 #ifdef CONFIG_X86
  56 #include <asm/nmi.h>
  57 #include <asm/stacktrace.h>
  58 #endif
  59
  60 #if defined(CONFIG_SYSCTL)
  61
  62 /* External variables not in a header file. */
  63 extern int C_A_D;
  64 extern int sysctl_overcommit_memory;
  65 extern int sysctl_overcommit_ratio;
  66 extern int sysctl_panic_on_oom;
  67 extern int max_threads;
  68 extern int core_uses_pid;
  69 extern int suid_dumpable;
  70 extern char core_pattern[];
  71 extern int pid_max;
  72 extern int min_free_kbytes;
  73 extern int printk_ratelimit_jiffies;
  74 extern int printk_ratelimit_burst;
  75 extern int pid_max_min, pid_max_max;
  76 extern int sysctl_drop_caches;
  77 extern int percpu_pagelist_fraction;
  78 extern int compat_log;
  79
  80 /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
  81 static int maxolduid = 65535;
  82 static int minolduid;
  83 static int min_percpu_pagelist_fract = 8;
  84
  85 static int ngroups_max = NGROUPS_MAX;
  86
  87 #ifdef CONFIG_KMOD
  88 extern char modprobe_path[];
  89 #endif
  90 #ifdef CONFIG_CHR_DEV_SG
  91 extern int sg_big_buff;
  92 #endif
  93
  94 #ifdef __sparc__
  95 extern char reboot_command [];
  96 extern int stop_a_enabled;
  97 extern int scons_pwroff;
  98 #endif
  99
 100 #ifdef __hppa__
 101 extern int pwrsw_enabled;
 102 extern int unaligned_enabled;
 103 #endif
 104
 105 #ifdef CONFIG_S390
 106 #ifdef CONFIG_MATHEMU
 107 extern int sysctl_ieee_emulation_warnings;
 108 #endif
 109 extern int sysctl_userprocess_debug;
 110 extern int spin_retry;
 111 #endif
 112
 113 extern int sysctl_hz_timer;
 114
 115 #ifdef CONFIG_BSD_PROCESS_ACCT
 116 extern int acct_parm[];
 117 #endif
 118
 119 #ifdef CONFIG_IA64
 120 extern int no_unaligned_warning;
 121 #endif
 122
 123 #ifdef CONFIG_RT_MUTEXES
 124 extern int max_lock_depth;
 125 #endif
 126
 127 #ifdef CONFIG_SYSCTL_SYSCALL
 128 static int parse_table(int __user *, int, void __user *, size_t __user *,
 129                 void __user *, size_t, ctl_table *);
 130 #endif
 131
 132
 133 #ifdef CONFIG_PROC_SYSCTL
 134 static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
 135                   void __user *buffer, size_t *lenp, loff_t *ppos);
 136 static int proc_dointvec_taint(ctl_table *table, int write, struct file *filp,
 137                                void __user *buffer, size_t *lenp, loff_t *ppos);
 138 #endif
 139
 140 static ctl_table root_table[];
 141 static struct ctl_table_header root_table_header =
 142         { root_table, LIST_HEAD_INIT(root_table_header.ctl_entry) };
 143
 144 static ctl_table kern_table[];
 145 static ctl_table vm_table[];
 146 static ctl_table fs_table[];
 147 static ctl_table debug_table[];
 148 static ctl_table dev_table[];
 149 extern ctl_table random_table[];
 150 #ifdef CONFIG_UNIX98_PTYS
 151 extern ctl_table pty_table[];
 152 #endif
 153 #ifdef CONFIG_INOTIFY_USER
 154 extern ctl_table inotify_table[];
 155 #endif
 156
 157 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 158 int sysctl_legacy_va_layout;
 159 #endif
 160
 161
 162 /* /proc declarations: */
 163
 164 #ifdef CONFIG_PROC_SYSCTL
 165
 166 static ssize_t proc_readsys(struct file *, char __user *, size_t, loff_t *);
 167 static ssize_t proc_writesys(struct file *, const char __user *, size_t, loff_t *);
 168 static int proc_opensys(struct inode *, struct file *);
 169
 170 const struct file_operations proc_sys_file_operations = {
 171         .open           = proc_opensys,
 172         .read           = proc_readsys,
 173         .write          = proc_writesys,
 174 };
 175
 176 extern struct proc_dir_entry *proc_sys_root;
 177
 178 static void register_proc_table(ctl_table *, struct proc_dir_entry *, void *);
 179 static void unregister_proc_table(ctl_table *, struct proc_dir_entry *);
 180 #endif
 181
 182 /* The default sysctl tables: */
 183
 184 static ctl_table root_table[] = {
 185         {
 186                 .ctl_name       = CTL_KERN,
 187                 .procname       = "kernel",
 188                 .mode           = 0555,
 189                 .child          = kern_table,
 190         },
 191         {
 192                 .ctl_name       = CTL_VM,
 193                 .procname       = "vm",
 194                 .mode           = 0555,
 195                 .child          = vm_table,
 196         },
 197 #ifdef CONFIG_NET
 198         {
 199                 .ctl_name       = CTL_NET,
 200                 .procname       = "net",
 201                 .mode           = 0555,
 202                 .child          = net_table,
 203         },
 204 #endif
 205         {
 206                 .ctl_name       = CTL_FS,
 207                 .procname       = "fs",
 208                 .mode           = 0555,
 209                 .child          = fs_table,
 210         },
 211         {
 212                 .ctl_name       = CTL_DEBUG,
 213                 .procname       = "debug",
 214                 .mode           = 0555,
 215                 .child          = debug_table,
 216         },
 217         {
 218                 .ctl_name       = CTL_DEV,
 219                 .procname       = "dev",
 220                 .mode           = 0555,
 221                 .child          = dev_table,
 222         },
 223
 224         { .ctl_name = 0 }
 225 };
 226
 227 static ctl_table kern_table[] = {
 228         {
 229                 .ctl_name       = KERN_PANIC,
 230                 .procname       = "panic",
 231                 .data           = &panic_timeout,
 232                 .maxlen         = sizeof(int),
 233                 .mode           = 0644,
 234                 .proc_handler   = &proc_dointvec,
 235         },
 236         {
 237                 .ctl_name       = KERN_CORE_USES_PID,
 238                 .procname       = "core_uses_pid",
 239                 .data           = &core_uses_pid,
 240                 .maxlen         = sizeof(int),
 241                 .mode           = 0644,
 242                 .proc_handler   = &proc_dointvec,
 243         },
 244         {
 245                 .ctl_name       = KERN_CORE_PATTERN,
 246                 .procname       = "core_pattern",
 247                 .data           = core_pattern,
 248                 .maxlen         = 128,
 249                 .mode           = 0644,
 250                 .proc_handler   = &proc_dostring,
 251                 .strategy       = &sysctl_string,
 252         },
 253 #ifdef CONFIG_PROC_SYSCTL
 254         {
 255                 .ctl_name       = KERN_TAINTED,
 256                 .procname       = "tainted",
 257                 .data           = &tainted,
 258                 .maxlen         = sizeof(int),
 259                 .mode           = 0644,
 260                 .proc_handler   = &proc_dointvec_taint,
 261         },
 262 #endif
 263         {
 264                 .ctl_name       = KERN_CAP_BSET,
 265                 .procname       = "cap-bound",
 266                 .data           = &cap_bset,
 267                 .maxlen         = sizeof(kernel_cap_t),
 268                 .mode           = 0600,
 269                 .proc_handler   = &proc_dointvec_bset,
 270         },
 271 #ifdef CONFIG_BLK_DEV_INITRD
 272         {
 273                 .ctl_name       = KERN_REALROOTDEV,
 274                 .procname       = "real-root-dev",
 275                 .data           = &real_root_dev,
 276                 .maxlen         = sizeof(int),
 277                 .mode           = 0644,
 278                 .proc_handler   = &proc_dointvec,
 279         },
 280 #endif
 281 #ifdef __sparc__
 282         {
 283                 .ctl_name       = KERN_SPARC_REBOOT,
 284                 .procname       = "reboot-cmd",
 285                 .data           = reboot_command,
 286                 .maxlen         = 256,
 287                 .mode           = 0644,
 288                 .proc_handler   = &proc_dostring,
 289                 .strategy       = &sysctl_string,
 290         },
 291         {
 292                 .ctl_name       = KERN_SPARC_STOP_A,
 293                 .procname       = "stop-a",
 294                 .data           = &stop_a_enabled,
 295                 .maxlen         = sizeof (int),
 296                 .mode           = 0644,
 297                 .proc_handler   = &proc_dointvec,
 298         },
 299         {
 300                 .ctl_name       = KERN_SPARC_SCONS_PWROFF,
 301                 .procname       = "scons-poweroff",
 302                 .data           = &scons_pwroff,
 303                 .maxlen         = sizeof (int),
 304                 .mode           = 0644,
 305                 .proc_handler   = &proc_dointvec,
 306         },
 307 #endif
 308 #ifdef __hppa__
 309         {
 310                 .ctl_name       = KERN_HPPA_PWRSW,
 311                 .procname       = "soft-power",
 312                 .data           = &pwrsw_enabled,
 313                 .maxlen         = sizeof (int),
 314                 .mode           = 0644,
 315                 .proc_handler   = &proc_dointvec,
 316         },
 317         {
 318                 .ctl_name       = KERN_HPPA_UNALIGNED,
 319                 .procname       = "unaligned-trap",
 320                 .data           = &unaligned_enabled,
 321                 .maxlen         = sizeof (int),
 322                 .mode           = 0644,
 323                 .proc_handler   = &proc_dointvec,
 324         },
 325 #endif
 326         {
 327                 .ctl_name       = KERN_CTLALTDEL,
 328                 .procname       = "ctrl-alt-del",
 329                 .data           = &C_A_D,
 330                 .maxlen         = sizeof(int),
 331                 .mode           = 0644,
 332                 .proc_handler   = &proc_dointvec,
 333         },
 334         {
 335                 .ctl_name       = KERN_PRINTK,
 336                 .procname       = "printk",
 337                 .data           = &console_loglevel,
 338                 .maxlen         = 4*sizeof(int),
 339                 .mode           = 0644,
 340                 .proc_handler   = &proc_dointvec,
 341         },
 342 #ifdef CONFIG_KMOD
 343         {
 344                 .ctl_name       = KERN_MODPROBE,
 345                 .procname       = "modprobe",
 346                 .data           = &modprobe_path,
 347                 .maxlen         = KMOD_PATH_LEN,
 348                 .mode           = 0644,
 349                 .proc_handler   = &proc_dostring,
 350                 .strategy       = &sysctl_string,
 351         },
 352 #endif
 353 #if defined(CONFIG_HOTPLUG) && defined(CONFIG_NET)
 354         {
 355                 .ctl_name       = KERN_HOTPLUG,
 356                 .procname       = "hotplug",
 357                 .data           = &uevent_helper,
 358                 .maxlen         = UEVENT_HELPER_PATH_LEN,
 359                 .mode           = 0644,
 360                 .proc_handler   = &proc_dostring,
 361                 .strategy       = &sysctl_string,
 362         },
 363 #endif
 364 #ifdef CONFIG_CHR_DEV_SG
 365         {
 366                 .ctl_name       = KERN_SG_BIG_BUFF,
 367                 .procname       = "sg-big-buff",
 368                 .data           = &sg_big_buff,
 369                 .maxlen         = sizeof (int),
 370                 .mode           = 0444,
 371                 .proc_handler   = &proc_dointvec,
 372         },
 373 #endif
 374 #ifdef CONFIG_BSD_PROCESS_ACCT
 375         {
 376                 .ctl_name       = KERN_ACCT,
 377                 .procname       = "acct",
 378                 .data           = &acct_parm,
 379                 .maxlen         = 3*sizeof(int),
 380                 .mode           = 0644,
 381                 .proc_handler   = &proc_dointvec,
 382         },
 383 #endif
 384 #ifdef CONFIG_MAGIC_SYSRQ
 385         {
 386                 .ctl_name       = KERN_SYSRQ,
 387                 .procname       = "sysrq",
 388                 .data           = &__sysrq_enabled,
 389                 .maxlen         = sizeof (int),
 390                 .mode           = 0644,
 391                 .proc_handler   = &proc_dointvec,
 392         },
 393 #endif
 394 #ifdef CONFIG_PROC_SYSCTL
 395         {
 396                 .ctl_name       = KERN_CADPID,
 397                 .procname       = "cad_pid",
 398                 .data           = NULL,
 399                 .maxlen         = sizeof (int),
 400                 .mode           = 0600,
 401                 .proc_handler   = &proc_do_cad_pid,
 402         },
 403 #endif
 404         {
 405                 .ctl_name       = KERN_MAX_THREADS,
 406                 .procname       = "threads-max",
 407                 .data           = &max_threads,
 408                 .maxlen         = sizeof(int),
 409                 .mode           = 0644,
 410                 .proc_handler   = &proc_dointvec,
 411         },
 412         {
 413                 .ctl_name       = KERN_RANDOM,
 414                 .procname       = "random",
 415                 .mode           = 0555,
 416                 .child          = random_table,
 417         },
 418 #ifdef CONFIG_UNIX98_PTYS
 419         {
 420                 .ctl_name       = KERN_PTY,
 421                 .procname       = "pty",
 422                 .mode           = 0555,
 423                 .child          = pty_table,
 424         },
 425 #endif
 426         {
 427                 .ctl_name       = KERN_OVERFLOWUID,
 428                 .procname       = "overflowuid",
 429                 .data           = &overflowuid,
 430                 .maxlen         = sizeof(int),
 431                 .mode           = 0644,
 432                 .proc_handler   = &proc_dointvec_minmax,
 433                 .strategy       = &sysctl_intvec,
 434                 .extra1         = &minolduid,
 435                 .extra2         = &maxolduid,
 436         },
 437         {
 438                 .ctl_name       = KERN_OVERFLOWGID,
 439                 .procname       = "overflowgid",
 440                 .data           = &overflowgid,
 441                 .maxlen         = sizeof(int),
 442                 .mode           = 0644,
 443                 .proc_handler   = &proc_dointvec_minmax,
 444                 .strategy       = &sysctl_intvec,
 445                 .extra1         = &minolduid,
 446                 .extra2         = &maxolduid,
 447         },
 448 #ifdef CONFIG_S390
 449 #ifdef CONFIG_MATHEMU
 450         {
 451                 .ctl_name       = KERN_IEEE_EMULATION_WARNINGS,
 452                 .procname       = "ieee_emulation_warnings",
 453                 .data           = &sysctl_ieee_emulation_warnings,
 454                 .maxlen         = sizeof(int),
 455                 .mode           = 0644,
 456                 .proc_handler   = &proc_dointvec,
 457         },
 458 #endif
 459 #ifdef CONFIG_NO_IDLE_HZ
 460         {
 461                 .ctl_name       = KERN_HZ_TIMER,
 462                 .procname       = "hz_timer",
 463                 .data           = &sysctl_hz_timer,
 464                 .maxlen         = sizeof(int),
 465                 .mode           = 0644,
 466                 .proc_handler   = &proc_dointvec,
 467         },
 468 #endif
 469         {
 470                 .ctl_name       = KERN_S390_USER_DEBUG_LOGGING,
 471                 .procname       = "userprocess_debug",
 472                 .data           = &sysctl_userprocess_debug,
 473                 .maxlen         = sizeof(int),
 474                 .mode           = 0644,
 475                 .proc_handler   = &proc_dointvec,
 476         },
 477 #endif
 478         {
 479                 .ctl_name       = KERN_PIDMAX,
 480                 .procname       = "pid_max",
 481                 .data           = &pid_max,
 482                 .maxlen         = sizeof (int),
 483                 .mode           = 0644,
 484                 .proc_handler   = &proc_dointvec_minmax,
 485                 .strategy       = sysctl_intvec,
 486                 .extra1         = &pid_max_min,
 487                 .extra2         = &pid_max_max,
 488         },
 489         {
 490                 .ctl_name       = KERN_PANIC_ON_OOPS,
 491                 .procname       = "panic_on_oops",
 492                 .data           = &panic_on_oops,
 493                 .maxlen         = sizeof(int),
 494                 .mode           = 0644,
 495                 .proc_handler   = &proc_dointvec,
 496         },
 497         {
 498                 .ctl_name       = KERN_PRINTK_RATELIMIT,
 499                 .procname       = "printk_ratelimit",
 500                 .data           = &printk_ratelimit_jiffies,
 501                 .maxlen         = sizeof(int),
 502                 .mode           = 0644,
 503                 .proc_handler   = &proc_dointvec_jiffies,
 504                 .strategy       = &sysctl_jiffies,
 505         },
 506         {
 507                 .ctl_name       = KERN_PRINTK_RATELIMIT_BURST,
 508                 .procname       = "printk_ratelimit_burst",
 509                 .data           = &printk_ratelimit_burst,
 510                 .maxlen         = sizeof(int),
 511                 .mode           = 0644,
 512                 .proc_handler   = &proc_dointvec,
 513         },
 514         {
 515                 .ctl_name       = KERN_NGROUPS_MAX,
 516                 .procname       = "ngroups_max",
 517                 .data           = &ngroups_max,
 518                 .maxlen         = sizeof (int),
 519                 .mode           = 0444,
 520                 .proc_handler   = &proc_dointvec,
 521         },
 522 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 523         {
 524                 .ctl_name       = KERN_UNKNOWN_NMI_PANIC,
 525                 .procname       = "unknown_nmi_panic",
 526                 .data           = &unknown_nmi_panic,
 527                 .maxlen         = sizeof (int),
 528                 .mode           = 0644,
 529                 .proc_handler   = &proc_dointvec,
 530         },
 531         {
 532                 .ctl_name       = KERN_NMI_WATCHDOG,
 533                 .procname       = "nmi_watchdog",
 534                 .data           = &nmi_watchdog_enabled,
 535                 .maxlen         = sizeof (int),
 536                 .mode           = 0644,
 537                 .proc_handler   = &proc_nmi_enabled,
 538         },
 539 #endif
 540 #if defined(CONFIG_X86)
 541         {
 542                 .ctl_name       = KERN_PANIC_ON_NMI,
 543                 .procname       = "panic_on_unrecovered_nmi",
 544                 .data           = &panic_on_unrecovered_nmi,
 545                 .maxlen         = sizeof(int),
 546                 .mode           = 0644,
 547                 .proc_handler   = &proc_dointvec,
 548         },
 549         {
 550                 .ctl_name       = KERN_BOOTLOADER_TYPE,
 551                 .procname       = "bootloader_type",
 552                 .data           = &bootloader_type,
 553                 .maxlen         = sizeof (int),
 554                 .mode           = 0444,
 555                 .proc_handler   = &proc_dointvec,
 556         },
 557         {
 558                 .ctl_name       = CTL_UNNUMBERED,
 559                 .procname       = "kstack_depth_to_print",
 560                 .data           = &kstack_depth_to_print,
 561                 .maxlen         = sizeof(int),
 562                 .mode           = 0644,
 563                 .proc_handler   = &proc_dointvec,
 564         },
 565 #endif
 566 #if defined(CONFIG_MMU)
 567         {
 568                 .ctl_name       = KERN_RANDOMIZE,
 569                 .procname       = "randomize_va_space",
 570                 .data           = &randomize_va_space,
 571                 .maxlen         = sizeof(int),
 572                 .mode           = 0644,
 573                 .proc_handler   = &proc_dointvec,
 574         },
 575 #endif
 576 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
 577         {
 578                 .ctl_name       = KERN_SPIN_RETRY,
 579                 .procname       = "spin_retry",
 580                 .data           = &spin_retry,
 581                 .maxlen         = sizeof (int),
 582                 .mode           = 0644,
 583                 .proc_handler   = &proc_dointvec,
 584         },
 585 #endif
 586 #ifdef CONFIG_ACPI_SLEEP
 587         {
 588                 .ctl_name       = KERN_ACPI_VIDEO_FLAGS,
 589                 .procname       = "acpi_video_flags",
 590                 .data           = &acpi_video_flags,
 591                 .maxlen         = sizeof (unsigned long),
 592                 .mode           = 0644,
 593                 .proc_handler   = &proc_doulongvec_minmax,
 594         },
 595 #endif
 596 #ifdef CONFIG_IA64
 597         {
 598                 .ctl_name       = KERN_IA64_UNALIGNED,
 599                 .procname       = "ignore-unaligned-usertrap",
 600                 .data           = &no_unaligned_warning,
 601                 .maxlen         = sizeof (int),
 602                 .mode           = 0644,
 603                 .proc_handler   = &proc_dointvec,
 604         },
 605 #endif
 606 #ifdef CONFIG_COMPAT
 607         {
 608                 .ctl_name       = KERN_COMPAT_LOG,
 609                 .procname       = "compat-log",
 610                 .data           = &compat_log,
 611                 .maxlen         = sizeof (int),
 612                 .mode           = 0644,
 613                 .proc_handler   = &proc_dointvec,
 614         },
 615 #endif
 616 #ifdef CONFIG_RT_MUTEXES
 617         {
 618                 .ctl_name       = KERN_MAX_LOCK_DEPTH,
 619                 .procname       = "max_lock_depth",
 620                 .data           = &max_lock_depth,
 621                 .maxlen         = sizeof(int),
 622                 .mode           = 0644,
 623                 .proc_handler   = &proc_dointvec,
 624         },
 625 #endif
 626
 627         { .ctl_name = 0 }
 628 };
 629
 630 /* Constants for minimum and maximum testing in vm_table.
 631    We use these as one-element integer vectors. */
 632 static int zero;
 633 static int one_hundred = 100;
 634
 635
 636 static ctl_table vm_table[] = {
 637         {
 638                 .ctl_name       = VM_OVERCOMMIT_MEMORY,
 639                 .procname       = "overcommit_memory",
 640                 .data           = &sysctl_overcommit_memory,
 641                 .maxlen         = sizeof(sysctl_overcommit_memory),
 642                 .mode           = 0644,
 643                 .proc_handler   = &proc_dointvec,
 644         },
 645         {
 646                 .ctl_name       = VM_PANIC_ON_OOM,
 647                 .procname       = "panic_on_oom",
 648                 .data           = &sysctl_panic_on_oom,
 649                 .maxlen         = sizeof(sysctl_panic_on_oom),
 650                 .mode           = 0644,
 651                 .proc_handler   = &proc_dointvec,
 652         },
 653         {
 654                 .ctl_name       = VM_OVERCOMMIT_RATIO,
 655                 .procname       = "overcommit_ratio",
 656                 .data           = &sysctl_overcommit_ratio,
 657                 .maxlen         = sizeof(sysctl_overcommit_ratio),
 658                 .mode           = 0644,
 659                 .proc_handler   = &proc_dointvec,
 660         },
 661         {
 662                 .ctl_name       = VM_PAGE_CLUSTER,
 663                 .procname       = "page-cluster",
 664                 .data           = &page_cluster,
 665                 .maxlen         = sizeof(int),
 666                 .mode           = 0644,
 667                 .proc_handler   = &proc_dointvec,
 668         },
 669         {
 670                 .ctl_name       = VM_DIRTY_BACKGROUND,
 671                 .procname       = "dirty_background_ratio",
 672                 .data           = &dirty_background_ratio,
 673                 .maxlen         = sizeof(dirty_background_ratio),
 674                 .mode           = 0644,
 675                 .proc_handler   = &proc_dointvec_minmax,
 676                 .strategy       = &sysctl_intvec,
 677                 .extra1         = &zero,
 678                 .extra2         = &one_hundred,
 679         },
 680         {
 681                 .ctl_name       = VM_DIRTY_RATIO,
 682                 .procname       = "dirty_ratio",
 683                 .data           = &vm_dirty_ratio,
 684                 .maxlen         = sizeof(vm_dirty_ratio),
 685                 .mode           = 0644,
 686                 .proc_handler   = &proc_dointvec_minmax,
 687                 .strategy       = &sysctl_intvec,
 688                 .extra1         = &zero,
 689                 .extra2         = &one_hundred,
 690         },
 691         {
 692                 .ctl_name       = VM_DIRTY_WB_CS,
 693                 .procname       = "dirty_writeback_centisecs",
 694                 .data           = &dirty_writeback_interval,
 695                 .maxlen         = sizeof(dirty_writeback_interval),
 696                 .mode           = 0644,
 697                 .proc_handler   = &dirty_writeback_centisecs_handler,
 698         },
 699         {
 700                 .ctl_name       = VM_DIRTY_EXPIRE_CS,
 701                 .procname       = "dirty_expire_centisecs",
 702                 .data           = &dirty_expire_interval,
 703                 .maxlen         = sizeof(dirty_expire_interval),
 704                 .mode           = 0644,
 705                 .proc_handler   = &proc_dointvec_userhz_jiffies,
 706         },
 707         {
 708                 .ctl_name       = VM_NR_PDFLUSH_THREADS,
 709                 .procname       = "nr_pdflush_threads",
 710                 .data           = &nr_pdflush_threads,
 711                 .maxlen         = sizeof nr_pdflush_threads,
 712                 .mode           = 0444 /* read-only*/,
 713                 .proc_handler   = &proc_dointvec,
 714         },
 715         {
 716                 .ctl_name       = VM_SWAPPINESS,
 717                 .procname       = "swappiness",
 718                 .data           = &vm_swappiness,
 719                 .maxlen         = sizeof(vm_swappiness),
 720                 .mode           = 0644,
 721                 .proc_handler   = &proc_dointvec_minmax,
 722                 .strategy       = &sysctl_intvec,
 723                 .extra1         = &zero,
 724                 .extra2         = &one_hundred,
 725         },
 726 #ifdef CONFIG_HUGETLB_PAGE
 727          {
 728                 .ctl_name       = VM_HUGETLB_PAGES,
 729                 .procname       = "nr_hugepages",
 730                 .data           = &max_huge_pages,
 731                 .maxlen         = sizeof(unsigned long),
 732                 .mode           = 0644,
 733                 .proc_handler   = &hugetlb_sysctl_handler,
 734                 .extra1         = (void *)&hugetlb_zero,
 735                 .extra2         = (void *)&hugetlb_infinity,
 736          },
 737          {
 738                 .ctl_name       = VM_HUGETLB_GROUP,
 739                 .procname       = "hugetlb_shm_group",
 740                 .data           = &sysctl_hugetlb_shm_group,
 741                 .maxlen         = sizeof(gid_t),
 742                 .mode           = 0644,
 743                 .proc_handler   = &proc_dointvec,
 744          },
 745 #endif
 746         {
 747                 .ctl_name       = VM_LOWMEM_RESERVE_RATIO,
 748                 .procname       = "lowmem_reserve_ratio",
 749                 .data           = &sysctl_lowmem_reserve_ratio,
 750                 .maxlen         = sizeof(sysctl_lowmem_reserve_ratio),
 751                 .mode           = 0644,
 752                 .proc_handler   = &lowmem_reserve_ratio_sysctl_handler,
 753                 .strategy       = &sysctl_intvec,
 754         },
 755         {
 756                 .ctl_name       = VM_DROP_PAGECACHE,
 757                 .procname       = "drop_caches",
 758                 .data           = &sysctl_drop_caches,
 759                 .maxlen         = sizeof(int),
 760                 .mode           = 0644,
 761                 .proc_handler   = drop_caches_sysctl_handler,
 762                 .strategy       = &sysctl_intvec,
 763         },
 764         {
 765                 .ctl_name       = VM_MIN_FREE_KBYTES,
 766                 .procname       = "min_free_kbytes",
 767                 .data           = &min_free_kbytes,
 768                 .maxlen         = sizeof(min_free_kbytes),
 769                 .mode           = 0644,
 770                 .proc_handler   = &min_free_kbytes_sysctl_handler,
 771                 .strategy       = &sysctl_intvec,
 772                 .extra1         = &zero,
 773         },
 774         {
 775                 .ctl_name       = VM_PERCPU_PAGELIST_FRACTION,
 776                 .procname       = "percpu_pagelist_fraction",
 777                 .data           = &percpu_pagelist_fraction,
 778                 .maxlen         = sizeof(percpu_pagelist_fraction),
 779                 .mode           = 0644,
 780                 .proc_handler   = &percpu_pagelist_fraction_sysctl_handler,
 781                 .strategy       = &sysctl_intvec,
 782                 .extra1         = &min_percpu_pagelist_fract,
 783         },
 784 #ifdef CONFIG_MMU
 785         {
 786                 .ctl_name       = VM_MAX_MAP_COUNT,
 787                 .procname       = "max_map_count",
 788                 .data           = &sysctl_max_map_count,
 789                 .maxlen         = sizeof(sysctl_max_map_count),
 790                 .mode           = 0644,
 791                 .proc_handler   = &proc_dointvec
 792         },
 793 #endif
 794         {
 795                 .ctl_name       = VM_LAPTOP_MODE,
 796                 .procname       = "laptop_mode",
 797                 .data           = &laptop_mode,
 798                 .maxlen         = sizeof(laptop_mode),
 799                 .mode           = 0644,
 800                 .proc_handler   = &proc_dointvec_jiffies,
 801                 .strategy       = &sysctl_jiffies,
 802         },
 803         {
 804                 .ctl_name       = VM_BLOCK_DUMP,
 805                 .procname       = "block_dump",
 806                 .data           = &block_dump,
 807                 .maxlen         = sizeof(block_dump),
 808                 .mode           = 0644,
 809                 .proc_handler   = &proc_dointvec,
 810                 .strategy       = &sysctl_intvec,
 811                 .extra1         = &zero,
 812         },
 813         {
 814                 .ctl_name       = VM_VFS_CACHE_PRESSURE,
 815                 .procname       = "vfs_cache_pressure",
 816                 .data           = &sysctl_vfs_cache_pressure,
 817                 .maxlen         = sizeof(sysctl_vfs_cache_pressure),
 818                 .mode           = 0644,
 819                 .proc_handler   = &proc_dointvec,
 820                 .strategy       = &sysctl_intvec,
 821                 .extra1         = &zero,
 822         },
 823 #ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
 824         {
 825                 .ctl_name       = VM_LEGACY_VA_LAYOUT,
 826                 .procname       = "legacy_va_layout",
 827                 .data           = &sysctl_legacy_va_layout,
 828                 .maxlen         = sizeof(sysctl_legacy_va_layout),
 829                 .mode           = 0644,
 830                 .proc_handler   = &proc_dointvec,
 831                 .strategy       = &sysctl_intvec,
 832                 .extra1         = &zero,
 833         },
 834 #endif
 835 #ifdef CONFIG_NUMA
 836         {
 837                 .ctl_name       = VM_ZONE_RECLAIM_MODE,
 838                 .procname       = "zone_reclaim_mode",
 839                 .data           = &zone_reclaim_mode,
 840                 .maxlen         = sizeof(zone_reclaim_mode),
 841                 .mode           = 0644,
 842                 .proc_handler   = &proc_dointvec,
 843                 .strategy       = &sysctl_intvec,
 844                 .extra1         = &zero,
 845         },
 846         {
 847                 .ctl_name       = VM_MIN_UNMAPPED,
 848                 .procname       = "min_unmapped_ratio",
 849                 .data           = &sysctl_min_unmapped_ratio,
 850                 .maxlen         = sizeof(sysctl_min_unmapped_ratio),
 851                 .mode           = 0644,
 852                 .proc_handler   = &sysctl_min_unmapped_ratio_sysctl_handler,
 853                 .strategy       = &sysctl_intvec,
 854                 .extra1         = &zero,
 855                 .extra2         = &one_hundred,
 856         },
 857         {
 858                 .ctl_name       = VM_MIN_SLAB,
 859                 .procname       = "min_slab_ratio",
 860                 .data           = &sysctl_min_slab_ratio,
 861                 .maxlen         = sizeof(sysctl_min_slab_ratio),
 862                 .mode           = 0644,
 863                 .proc_handler   = &sysctl_min_slab_ratio_sysctl_handler,
 864                 .strategy       = &sysctl_intvec,
 865                 .extra1         = &zero,
 866                 .extra2         = &one_hundred,
 867         },
 868 #endif
 869 #ifdef CONFIG_X86_32
 870         {
 871                 .ctl_name       = VM_VDSO_ENABLED,
 872                 .procname       = "vdso_enabled",
 873                 .data           = &vdso_enabled,
 874                 .maxlen         = sizeof(vdso_enabled),
 875                 .mode           = 0644,
 876                 .proc_handler   = &proc_dointvec,
 877                 .strategy       = &sysctl_intvec,
 878                 .extra1         = &zero,
 879         },
 880 #endif
 881         { .ctl_name = 0 }
 882 };
 883
 884 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
 885 static ctl_table binfmt_misc_table[] = {
 886         { .ctl_name = 0 }
 887 };
 888 #endif
 889
 890 static ctl_table fs_table[] = {
 891         {
 892                 .ctl_name       = FS_NRINODE,
 893                 .procname       = "inode-nr",
 894                 .data           = &inodes_stat,
 895                 .maxlen         = 2*sizeof(int),
 896                 .mode           = 0444,
 897                 .proc_handler   = &proc_dointvec,
 898         },
 899         {
 900                 .ctl_name       = FS_STATINODE,
 901                 .procname       = "inode-state",
 902                 .data           = &inodes_stat,
 903                 .maxlen         = 7*sizeof(int),
 904                 .mode           = 0444,
 905                 .proc_handler   = &proc_dointvec,
 906         },
 907         {
 908                 .ctl_name       = FS_NRFILE,
 909                 .procname       = "file-nr",
 910                 .data           = &files_stat,
 911                 .maxlen         = 3*sizeof(int),
 912                 .mode           = 0444,
 913                 .proc_handler   = &proc_nr_files,
 914         },
 915         {
 916                 .ctl_name       = FS_MAXFILE,
 917                 .procname       = "file-max",
 918                 .data           = &files_stat.max_files,
 919                 .maxlen         = sizeof(int),
 920                 .mode           = 0644,
 921                 .proc_handler   = &proc_dointvec,
 922         },
 923         {
 924                 .ctl_name       = FS_DENTRY,
 925                 .procname       = "dentry-state",
 926                 .data           = &dentry_stat,
 927                 .maxlen         = 6*sizeof(int),
 928                 .mode           = 0444,
 929                 .proc_handler   = &proc_dointvec,
 930         },
 931         {
 932                 .ctl_name       = FS_OVERFLOWUID,
 933                 .procname       = "overflowuid",
 934                 .data           = &fs_overflowuid,
 935                 .maxlen         = sizeof(int),
 936                 .mode           = 0644,
 937                 .proc_handler   = &proc_dointvec_minmax,
 938                 .strategy       = &sysctl_intvec,
 939                 .extra1         = &minolduid,
 940                 .extra2         = &maxolduid,
 941         },
 942         {
 943                 .ctl_name       = FS_OVERFLOWGID,
 944                 .procname       = "overflowgid",
 945                 .data           = &fs_overflowgid,
 946                 .maxlen         = sizeof(int),
 947                 .mode           = 0644,
 948                 .proc_handler   = &proc_dointvec_minmax,
 949                 .strategy       = &sysctl_intvec,
 950                 .extra1         = &minolduid,
 951                 .extra2         = &maxolduid,
 952         },
 953         {
 954                 .ctl_name       = FS_LEASES,
 955                 .procname       = "leases-enable",
 956                 .data           = &leases_enable,
 957                 .maxlen         = sizeof(int),
 958                 .mode           = 0644,
 959                 .proc_handler   = &proc_dointvec,
 960         },
 961 #ifdef CONFIG_DNOTIFY
 962         {
 963                 .ctl_name       = FS_DIR_NOTIFY,
 964                 .procname       = "dir-notify-enable",
 965                 .data           = &dir_notify_enable,
 966                 .maxlen         = sizeof(int),
 967                 .mode           = 0644,
 968                 .proc_handler   = &proc_dointvec,
 969         },
 970 #endif
 971 #ifdef CONFIG_MMU
 972         {
 973                 .ctl_name       = FS_LEASE_TIME,
 974                 .procname       = "lease-break-time",
 975                 .data           = &lease_break_time,
 976                 .maxlen         = sizeof(int),
 977                 .mode           = 0644,
 978                 .proc_handler   = &proc_dointvec,
 979         },
 980         {
 981                 .ctl_name       = FS_AIO_NR,
 982                 .procname       = "aio-nr",
 983                 .data           = &aio_nr,
 984                 .maxlen         = sizeof(aio_nr),
 985                 .mode           = 0444,
 986                 .proc_handler   = &proc_doulongvec_minmax,
 987         },
 988         {
 989                 .ctl_name       = FS_AIO_MAX_NR,
 990                 .procname       = "aio-max-nr",
 991                 .data           = &aio_max_nr,
 992                 .maxlen         = sizeof(aio_max_nr),
 993                 .mode           = 0644,
 994                 .proc_handler   = &proc_doulongvec_minmax,
 995         },
 996 #ifdef CONFIG_INOTIFY_USER
 997         {
 998                 .ctl_name       = FS_INOTIFY,
 999                 .procname       = "inotify",
1000                 .mode           = 0555,
1001                 .child          = inotify_table,
1002         },
1003 #endif
1004 #endif
1005         {
1006                 .ctl_name       = KERN_SETUID_DUMPABLE,
1007                 .procname       = "suid_dumpable",
1008                 .data           = &suid_dumpable,
1009                 .maxlen         = sizeof(int),
1010                 .mode           = 0644,
1011                 .proc_handler   = &proc_dointvec,
1012         },
1013 #if defined(CONFIG_BINFMT_MISC) || defined(CONFIG_BINFMT_MISC_MODULE)
1014         {
1015                 .ctl_name       = CTL_UNNUMBERED,
1016                 .procname       = "binfmt_misc",
1017                 .mode           = 0555,
1018                 .child          = binfmt_misc_table,
1019         },
1020 #endif
1021         { .ctl_name = 0 }
1022 };
1023
1024 static ctl_table debug_table[] = {
1025         { .ctl_name = 0 }
1026 };
1027
1028 static ctl_table dev_table[] = {
1029         { .ctl_name = 0 }
1030 };
1031
1032 static DEFINE_SPINLOCK(sysctl_lock);
1033
1034 /* called under sysctl_lock */
1035 static int use_table(struct ctl_table_header *p)
1036 {
1037         if (unlikely(p->unregistering))
1038                 return 0;
1039         p->used++;
1040         return 1;
1041 }
1042
1043 /* called under sysctl_lock */
1044 static void unuse_table(struct ctl_table_header *p)
1045 {
1046         if (!--p->used)
1047                 if (unlikely(p->unregistering))
1048                         complete(p->unregistering);
1049 }
1050
1051 /* called under sysctl_lock, will reacquire if has to wait */
1052 static void start_unregistering(struct ctl_table_header *p)
1053 {
1054         /*
1055          * if p->used is 0, nobody will ever touch that entry again;
1056          * we'll eliminate all paths to it before dropping sysctl_lock
1057          */
1058         if (unlikely(p->used)) {
1059                 struct completion wait;
1060                 init_completion(&wait);
1061                 p->unregistering = &wait;
1062                 spin_unlock(&sysctl_lock);
1063                 wait_for_completion(&wait);
1064                 spin_lock(&sysctl_lock);
1065         }
1066         /*
1067          * do not remove from the list until nobody holds it; walking the
1068          * list in do_sysctl() relies on that.
1069          */
1070         list_del_init(&p->ctl_entry);
1071 }
1072
1073 void __init sysctl_init(void)
1074 {
1075 #ifdef CONFIG_PROC_SYSCTL
1076         register_proc_table(root_table, proc_sys_root, &root_table_header);
1077 #endif
1078 }
1079
1080 #ifdef CONFIG_SYSCTL_SYSCALL
1081 int do_sysctl(int __user *name, int nlen, void __user *oldval, size_t __user *oldlenp,
1082                void __user *newval, size_t newlen)
1083 {
1084         struct list_head *tmp;
1085         int error = -ENOTDIR;
1086
1087         if (nlen <= 0 || nlen >= CTL_MAXNAME)
1088                 return -ENOTDIR;
1089         if (oldval) {
1090                 int old_len;
1091                 if (!oldlenp || get_user(old_len, oldlenp))
1092                         return -EFAULT;
1093         }
1094         spin_lock(&sysctl_lock);
1095         tmp = &root_table_header.ctl_entry;
1096         do {
1097                 struct ctl_table_header *head =
1098                         list_entry(tmp, struct ctl_table_header, ctl_entry);
1099
1100                 if (!use_table(head))
1101                         continue;
1102
1103                 spin_unlock(&sysctl_lock);
1104
1105                 error = parse_table(name, nlen, oldval, oldlenp,
1106                                         newval, newlen, head->ctl_table);
1107
1108                 spin_lock(&sysctl_lock);
1109                 unuse_table(head);
1110                 if (error != -ENOTDIR)
1111                         break;
1112         } while ((tmp = tmp->next) != &root_table_header.ctl_entry);
1113         spin_unlock(&sysctl_lock);
1114         return error;
1115 }
1116
1117 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
1118 {
1119         struct __sysctl_args tmp;
1120         int error;
1121
1122         if (copy_from_user(&tmp, args, sizeof(tmp)))
1123                 return -EFAULT;
1124
1125         lock_kernel();
1126         error = do_sysctl(tmp.name, tmp.nlen, tmp.oldval, tmp.oldlenp,
1127                           tmp.newval, tmp.newlen);
1128         unlock_kernel();
1129         return error;
1130 }
1131 #endif /* CONFIG_SYSCTL_SYSCALL */
1132
1133 /*
1134  * ctl_perm does NOT grant the superuser all rights automatically, because
1135  * some sysctl variables are readonly even to root.
1136  */
1137
1138 static int test_perm(int mode, int op)
1139 {
1140         if (!current->euid)
1141                 mode >>= 6;
1142         else if (in_egroup_p(0))
1143                 mode >>= 3;
1144         if ((mode & op & 0007) == op)
1145                 return 0;
1146         return -EACCES;
1147 }
1148
1149 static inline int ctl_perm(ctl_table *table, int op)
1150 {
1151         int error;
1152         error = security_sysctl(table, op);
1153         if (error)
1154                 return error;
1155         return test_perm(table->mode, op);
1156 }
1157
1158 #ifdef CONFIG_SYSCTL_SYSCALL
1159 static int parse_table(int __user *name, int nlen,
1160                        void __user *oldval, size_t __user *oldlenp,
1161                        void __user *newval, size_t newlen,
1162                        ctl_table *table)
1163 {
1164         int n;
1165 repeat:
1166         if (!nlen)
1167                 return -ENOTDIR;
1168         if (get_user(n, name))
1169                 return -EFAULT;
1170         for ( ; table->ctl_name || table->procname; table++) {
1171                 if (!table->ctl_name)
1172                         continue;
1173                 if (n == table->ctl_name) {
1174                         int error;
1175                         if (table->child) {
1176                                 if (ctl_perm(table, 001))
1177                                         return -EPERM;
1178                                 name++;
1179                                 nlen--;
1180                                 table = table->child;
1181                                 goto repeat;
1182                         }
1183                         error = do_sysctl_strategy(table, name, nlen,
1184                                                    oldval, oldlenp,
1185                                                    newval, newlen);
1186                         return error;
1187                 }
1188         }
1189         return -ENOTDIR;
1190 }
1191
1192 /* Perform the actual read/write of a sysctl table entry. */
1193 int do_sysctl_strategy (ctl_table *table,
1194                         int __user *name, int nlen,
1195                         void __user *oldval, size_t __user *oldlenp,
1196                         void __user *newval, size_t newlen)
1197 {
1198         int op = 0, rc;
1199         size_t len;
1200
1201         if (oldval)
1202                 op |= 004;
1203         if (newval)
1204                 op |= 002;
1205         if (ctl_perm(table, op))
1206                 return -EPERM;
1207
1208         if (table->strategy) {
1209                 rc = table->strategy(table, name, nlen, oldval, oldlenp,
1210                                      newval, newlen);
1211                 if (rc < 0)
1212                         return rc;
1213                 if (rc > 0)
1214                         return 0;
1215         }
1216
1217         /* If there is no strategy routine, or if the strategy returns
1218          * zero, proceed with automatic r/w */
1219         if (table->data && table->maxlen) {
1220                 if (oldval && oldlenp) {
1221                         if (get_user(len, oldlenp))
1222                                 return -EFAULT;
1223                         if (len) {
1224                                 if (len > table->maxlen)
1225                                         len = table->maxlen;
1226                                 if(copy_to_user(oldval, table->data, len))
1227                                         return -EFAULT;
1228                                 if(put_user(len, oldlenp))
1229                                         return -EFAULT;
1230                         }
1231                 }
1232                 if (newval && newlen) {
1233                         len = newlen;
1234                         if (len > table->maxlen)
1235                                 len = table->maxlen;
1236                         if(copy_from_user(table->data, newval, len))
1237                                 return -EFAULT;
1238                 }
1239         }
1240         return 0;
1241 }
1242 #endif /* CONFIG_SYSCTL_SYSCALL */
1243
1244 /**
1245  * register_sysctl_table - register a sysctl hierarchy
1246  * @table: the top-level table structure
1247  *
1248  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
1249  * array. An entry with a ctl_name of 0 terminates the table.
1250  *
1251  * The members of the &ctl_table structure are used as follows:
1252  *
1253  * ctl_name - This is the numeric sysctl value used by sysctl(2). The number
1254  *            must be unique within that level of sysctl
1255  *
1256  * procname - the name of the sysctl file under /proc/sys. Set to %NULL to not
1257  *            enter a sysctl file
1258  *
1259  * data - a pointer to data for use by proc_handler
1260  *
1261  * maxlen - the maximum size in bytes of the data
1262  *
1263  * mode - the file permissions for the /proc/sys file, and for sysctl(2)
1264  *
1265  * child - a pointer to the child sysctl table if this entry is a directory, or
1266  *         %NULL.
1267  *
1268  * proc_handler - the text handler routine (described below)
1269  *
1270  * strategy - the strategy routine (described below)
1271  *
1272  * de - for internal use by the sysctl routines
1273  *
1274  * extra1, extra2 - extra pointers usable by the proc handler routines
1275  *
1276  * Leaf nodes in the sysctl tree will be represented by a single file
1277  * under /proc; non-leaf nodes will be represented by directories.
1278  *
1279  * sysctl(2) can automatically manage read and write requests through
1280  * the sysctl table.  The data and maxlen fields of the ctl_table
1281  * struct enable minimal validation of the values being written to be
1282  * performed, and the mode field allows minimal authentication.
1283  *
1284  * More sophisticated management can be enabled by the provision of a
1285  * strategy routine with the table entry.  This will be called before
1286  * any automatic read or write of the data is performed.
1287  *
1288  * The strategy routine may return
1289  *
1290  * < 0 - Error occurred (error is passed to user process)
1291  *
1292  * 0   - OK - proceed with automatic read or write.
1293  *
1294  * > 0 - OK - read or write has been done by the strategy routine, so
1295  *       return immediately.
1296  *
1297  * There must be a proc_handler routine for any terminal nodes
1298  * mirrored under /proc/sys (non-terminals are handled by a built-in
1299  * directory handler).  Several default handlers are available to
1300  * cover common cases -
1301  *
1302  * proc_dostring(), proc_dointvec(), proc_dointvec_jiffies(),
1303  * proc_dointvec_userhz_jiffies(), proc_dointvec_minmax(),
1304  * proc_doulongvec_ms_jiffies_minmax(), proc_doulongvec_minmax()
1305  *
1306  * It is the handler's job to read the input buffer from user memory
1307  * and process it. The handler should return 0 on success.
1308  *
1309  * This routine returns %NULL on a failure to register, and a pointer
1310  * to the table header on success.
1311  */
1312 struct ctl_table_header *register_sysctl_table(ctl_table * table)
1313 {
1314         struct ctl_table_header *tmp;
1315         tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
1316         if (!tmp)
1317                 return NULL;
1318         tmp->ctl_table = table;
1319         INIT_LIST_HEAD(&tmp->ctl_entry);
1320         tmp->used = 0;
1321         tmp->unregistering = NULL;
1322         spin_lock(&sysctl_lock);
1323         list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
1324         spin_unlock(&sysctl_lock);
1325 #ifdef CONFIG_PROC_SYSCTL
1326         register_proc_table(table, proc_sys_root, tmp);
1327 #endif
1328         return tmp;
1329 }
1330
1331 /**
1332  * unregister_sysctl_table - unregister a sysctl table hierarchy
1333  * @header: the header returned from register_sysctl_table
1334  *
1335  * Unregisters the sysctl table and all children. proc entries may not
1336  * actually be removed until they are no longer used by anyone.
1337  */
1338 void unregister_sysctl_table(struct ctl_table_header * header)
1339 {
1340         might_sleep();
1341         spin_lock(&sysctl_lock);
1342         start_unregistering(header);
1343 #ifdef CONFIG_PROC_SYSCTL
1344         unregister_proc_table(header->ctl_table, proc_sys_root);
1345 #endif
1346         spin_unlock(&sysctl_lock);
1347         kfree(header);
1348 }
1349
1350 #else /* !CONFIG_SYSCTL */
1351 struct ctl_table_header * register_sysctl_table(ctl_table * table,
1352                                                 int insert_at_head)
1353 {
1354         return NULL;
1355 }
1356
1357 void unregister_sysctl_table(struct ctl_table_header * table)
1358 {
1359 }
1360
1361 #endif /* CONFIG_SYSCTL */
1362
1363 /*
1364  * /proc/sys support
1365  */
1366
1367 #ifdef CONFIG_PROC_SYSCTL
1368
1369 /* Scan the sysctl entries in table and add them all into /proc */
1370 static void register_proc_table(ctl_table * table, struct proc_dir_entry *root, void *set)
1371 {
1372         struct proc_dir_entry *de;
1373         int len;
1374         mode_t mode;
1375
1376         for (; table->ctl_name || table->procname; table++) {
1377                 /* Can't do anything without a proc name. */
1378                 if (!table->procname)
1379                         continue;
1380                 /* Maybe we can't do anything with it... */
1381                 if (!table->proc_handler && !table->child) {
1382                         printk(KERN_WARNING "SYSCTL: Can't register %s\n",
1383                                 table->procname);
1384                         continue;
1385                 }
1386
1387                 len = strlen(table->procname);
1388                 mode = table->mode;
1389
1390                 de = NULL;
1391                 if (table->proc_handler)
1392                         mode |= S_IFREG;
1393                 else {
1394                         mode |= S_IFDIR;
1395                         for (de = root->subdir; de; de = de->next) {
1396                                 if (proc_match(len, table->procname, de))
1397                                         break;
1398                         }
1399                         /* If the subdir exists already, de is non-NULL */
1400                 }
1401
1402                 if (!de) {
1403                         de = create_proc_entry(table->procname, mode, root);
1404                         if (!de)
1405                                 continue;
1406                         de->set = set;
1407                         de->data = (void *) table;
1408                         if (table->proc_handler)
1409                                 de->proc_fops = &proc_sys_file_operations;
1410                 }
1411                 table->de = de;
1412                 if (de->mode & S_IFDIR)
1413                         register_proc_table(table->child, de, set);
1414         }
1415 }
1416
1417 /*
1418  * Unregister a /proc sysctl table and any subdirectories.
1419  */
1420 static void unregister_proc_table(ctl_table * table, struct proc_dir_entry *root)
1421 {
1422         struct proc_dir_entry *de;
1423         for (; table->ctl_name || table->procname; table++) {
1424                 if (!(de = table->de))
1425                         continue;
1426                 if (de->mode & S_IFDIR) {
1427                         if (!table->child) {
1428                                 printk (KERN_ALERT "Help - malformed sysctl tree on free\n");
1429                                 continue;
1430                         }
1431                         unregister_proc_table(table->child, de);
1432
1433                         /* Don't unregister directories which still have entries.. */
1434                         if (de->subdir)
1435                                 continue;
1436                 }
1437
1438                 /*
1439                  * In any case, mark the entry as goner; we'll keep it
1440                  * around if it's busy, but we'll know to do nothing with
1441                  * its fields.  We are under sysctl_lock here.
1442                  */
1443                 de->data = NULL;
1444
1445                 /* Don't unregister proc entries that are still being used.. */
1446                 if (atomic_read(&de->count))
1447                         continue;
1448
1449                 table->de = NULL;
1450                 remove_proc_entry(table->procname, root);
1451         }
1452 }
1453
1454 static ssize_t do_rw_proc(int write, struct file * file, char __user * buf,
1455                           size_t count, loff_t *ppos)
1456 {
1457         int op;
1458         struct proc_dir_entry *de = PDE(file->f_path.dentry->d_inode);
1459         struct ctl_table *table;
1460         size_t res;
1461         ssize_t error = -ENOTDIR;
1462
1463         spin_lock(&sysctl_lock);
1464         if (de && de->data && use_table(de->set)) {
1465                 /*
1466                  * at that point we know that sysctl was not unregistered
1467                  * and won't be until we finish
1468                  */
1469                 spin_unlock(&sysctl_lock);
1470                 table = (struct ctl_table *) de->data;
1471                 if (!table || !table->proc_handler)
1472                         goto out;
1473                 error = -EPERM;
1474                 op = (write ? 002 : 004);
1475                 if (ctl_perm(table, op))
1476                         goto out;
1477
1478                 /* careful: calling conventions are nasty here */
1479                 res = count;
1480                 error = (*table->proc_handler)(table, write, file,
1481                                                 buf, &res, ppos);
1482                 if (!error)
1483                         error = res;
1484         out:
1485                 spin_lock(&sysctl_lock);
1486                 unuse_table(de->set);
1487         }
1488         spin_unlock(&sysctl_lock);
1489         return error;
1490 }
1491
1492 static int proc_opensys(struct inode *inode, struct file *file)
1493 {
1494         if (file->f_mode & FMODE_WRITE) {
1495                 /*
1496                  * sysctl entries that are not writable,
1497                  * are _NOT_ writable, capabilities or not.
1498                  */
1499                 if (!(inode->i_mode & S_IWUSR))
1500                         return -EPERM;
1501         }
1502
1503         return 0;
1504 }
1505
1506 static ssize_t proc_readsys(struct file * file, char __user * buf,
1507                             size_t count, loff_t *ppos)
1508 {
1509         return do_rw_proc(0, file, buf, count, ppos);
1510 }
1511
1512 static ssize_t proc_writesys(struct file * file, const char __user * buf,
1513                              size_t count, loff_t *ppos)
1514 {
1515         return do_rw_proc(1, file, (char __user *) buf, count, ppos);
1516 }
1517
1518 static int _proc_do_string(void* data, int maxlen, int write,
1519                            struct file *filp, void __user *buffer,
1520                            size_t *lenp, loff_t *ppos)
1521 {
1522         size_t len;
1523         char __user *p;
1524         char c;
1525
1526         if (!data || !maxlen || !*lenp) {
1527                 *lenp = 0;
1528                 return 0;
1529         }
1530
1531         if (write) {
1532                 len = 0;
1533                 p = buffer;
1534                 while (len < *lenp) {
1535                         if (get_user(c, p++))
1536                                 return -EFAULT;
1537                         if (c == 0 || c == '\n')
1538                                 break;
1539                         len++;
1540                 }
1541                 if (len >= maxlen)
1542                         len = maxlen-1;
1543                 if(copy_from_user(data, buffer, len))
1544                         return -EFAULT;
1545                 ((char *) data)[len] = 0;
1546                 *ppos += *lenp;
1547         } else {
1548                 len = strlen(data);
1549                 if (len > maxlen)
1550                         len = maxlen;
1551
1552                 if (*ppos > len) {
1553                         *lenp = 0;
1554                         return 0;
1555                 }
1556
1557                 data += *ppos;
1558                 len  -= *ppos;
1559
1560                 if (len > *lenp)
1561                         len = *lenp;
1562                 if (len)
1563                         if(copy_to_user(buffer, data, len))
1564                                 return -EFAULT;
1565                 if (len < *lenp) {
1566                         if(put_user('\n', ((char __user *) buffer) + len))
1567                                 return -EFAULT;
1568                         len++;
1569                 }
1570                 *lenp = len;
1571                 *ppos += len;
1572         }
1573         return 0;
1574 }
1575
1576 /**
1577  * proc_dostring - read a string sysctl
1578  * @table: the sysctl table
1579  * @write: %TRUE if this is a write to the sysctl file
1580  * @filp: the file structure
1581  * @buffer: the user buffer
1582  * @lenp: the size of the user buffer
1583  * @ppos: file position
1584  *
1585  * Reads/writes a string from/to the user buffer. If the kernel
1586  * buffer provided is not large enough to hold the string, the
1587  * string is truncated. The copied string is %NULL-terminated.
1588  * If the string is being read by the user process, it is copied
1589  * and a newline '\n' is added. It is truncated if the buffer is
1590  * not large enough.
1591  *
1592  * Returns 0 on success.
1593  */
1594 int proc_dostring(ctl_table *table, int write, struct file *filp,
1595                   void __user *buffer, size_t *lenp, loff_t *ppos)
1596 {
1597         return _proc_do_string(table->data, table->maxlen, write, filp,
1598                                buffer, lenp, ppos);
1599 }
1600
1601
1602 static int do_proc_dointvec_conv(int *negp, unsigned long *lvalp,
1603                                  int *valp,
1604                                  int write, void *data)
1605 {
1606         if (write) {
1607                 *valp = *negp ? -*lvalp : *lvalp;
1608         } else {
1609                 int val = *valp;
1610                 if (val < 0) {
1611                         *negp = -1;
1612                         *lvalp = (unsigned long)-val;
1613                 } else {
1614                         *negp = 0;
1615                         *lvalp = (unsigned long)val;
1616                 }
1617         }
1618         return 0;
1619 }
1620
1621 static int __do_proc_dointvec(void *tbl_data, ctl_table *table,
1622                   int write, struct file *filp, void __user *buffer,
1623                   size_t *lenp, loff_t *ppos,
1624                   int (*conv)(int *negp, unsigned long *lvalp, int *valp,
1625                               int write, void *data),
1626                   void *data)
1627 {
1628 #define TMPBUFLEN 21
1629         int *i, vleft, first=1, neg, val;
1630         unsigned long lval;
1631         size_t left, len;
1632
1633         char buf[TMPBUFLEN], *p;
1634         char __user *s = buffer;
1635
1636         if (!tbl_data || !table->maxlen || !*lenp ||
1637             (*ppos && !write)) {
1638                 *lenp = 0;
1639                 return 0;
1640         }
1641
1642         i = (int *) tbl_data;
1643         vleft = table->maxlen / sizeof(*i);
1644         left = *lenp;
1645
1646         if (!conv)
1647                 conv = do_proc_dointvec_conv;
1648
1649         for (; left && vleft--; i++, first=0) {
1650                 if (write) {
1651                         while (left) {
1652                                 char c;
1653                                 if (get_user(c, s))
1654                                         return -EFAULT;
1655                                 if (!isspace(c))
1656                                         break;
1657                                 left--;
1658                                 s++;
1659                         }
1660                         if (!left)
1661                                 break;
1662                         neg = 0;
1663                         len = left;
1664                         if (len > sizeof(buf) - 1)
1665                                 len = sizeof(buf) - 1;
1666                         if (copy_from_user(buf, s, len))
1667                                 return -EFAULT;
1668                         buf[len] = 0;
1669                         p = buf;
1670                         if (*p == '-' && left > 1) {
1671                                 neg = 1;
1672                                 p++;
1673                         }
1674                         if (*p < '0' || *p > '9')
1675                                 break;
1676
1677                         lval = simple_strtoul(p, &p, 0);
1678
1679                         len = p-buf;
1680                         if ((len < left) && *p && !isspace(*p))
1681                                 break;
1682                         if (neg)
1683                                 val = -val;
1684                         s += len;
1685                         left -= len;
1686
1687                         if (conv(&neg, &lval, i, 1, data))
1688                                 break;
1689                 } else {
1690                         p = buf;
1691                         if (!first)
1692                                 *p++ = '\t';
1693
1694                         if (conv(&neg, &lval, i, 0, data))
1695                                 break;
1696
1697                         sprintf(p, "%s%lu", neg ? "-" : "", lval);
1698                         len = strlen(buf);
1699                         if (len > left)
1700                                 len = left;
1701                         if(copy_to_user(s, buf, len))
1702                                 return -EFAULT;
1703                         left -= len;
1704                         s += len;
1705                 }
1706         }
1707
1708         if (!write && !first && left) {
1709                 if(put_user('\n', s))
1710                         return -EFAULT;
1711                 left--, s++;
1712         }
1713         if (write) {
1714                 while (left) {
1715                         char c;
1716                         if (get_user(c, s++))
1717                                 return -EFAULT;
1718                         if (!isspace(c))
1719                                 break;
1720                         left--;
1721                 }
1722         }
1723         if (write && first)
1724                 return -EINVAL;
1725         *lenp -= left;
1726         *ppos += *lenp;
1727         return 0;
1728 #undef TMPBUFLEN
1729 }
1730
1731 static int do_proc_dointvec(ctl_table *table, int write, struct file *filp,
1732                   void __user *buffer, size_t *lenp, loff_t *ppos,
1733                   int (*conv)(int *negp, unsigned long *lvalp, int *valp,
1734                               int write, void *data),
1735                   void *data)
1736 {
1737         return __do_proc_dointvec(table->data, table, write, filp,
1738                         buffer, lenp, ppos, conv, data);
1739 }
1740
1741 /**
1742  * proc_dointvec - read a vector of integers
1743  * @table: the sysctl table
1744  * @write: %TRUE if this is a write to the sysctl file
1745  * @filp: the file structure
1746  * @buffer: the user buffer
1747  * @lenp: the size of the user buffer
1748  * @ppos: file position
1749  *
1750  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1751  * values from/to the user buffer, treated as an ASCII string.
1752  *
1753  * Returns 0 on success.
1754  */
1755 int proc_dointvec(ctl_table *table, int write, struct file *filp,
1756                      void __user *buffer, size_t *lenp, loff_t *ppos)
1757 {
1758     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1759                             NULL,NULL);
1760 }
1761
1762 #define OP_SET  0
1763 #define OP_AND  1
1764 #define OP_OR   2
1765
1766 static int do_proc_dointvec_bset_conv(int *negp, unsigned long *lvalp,
1767                                       int *valp,
1768                                       int write, void *data)
1769 {
1770         int op = *(int *)data;
1771         if (write) {
1772                 int val = *negp ? -*lvalp : *lvalp;
1773                 switch(op) {
1774                 case OP_SET:    *valp = val; break;
1775                 case OP_AND:    *valp &= val; break;
1776                 case OP_OR:     *valp |= val; break;
1777                 }
1778         } else {
1779                 int val = *valp;
1780                 if (val < 0) {
1781                         *negp = -1;
1782                         *lvalp = (unsigned long)-val;
1783                 } else {
1784                         *negp = 0;
1785                         *lvalp = (unsigned long)val;
1786                 }
1787         }
1788         return 0;
1789 }
1790
1791 /*
1792  *      init may raise the set.
1793  */
1794
1795 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
1796                         void __user *buffer, size_t *lenp, loff_t *ppos)
1797 {
1798         int op;
1799
1800         if (write && !capable(CAP_SYS_MODULE)) {
1801                 return -EPERM;
1802         }
1803
1804         op = is_init(current) ? OP_SET : OP_AND;
1805         return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1806                                 do_proc_dointvec_bset_conv,&op);
1807 }
1808
1809 /*
1810  *      Taint values can only be increased
1811  */
1812 static int proc_dointvec_taint(ctl_table *table, int write, struct file *filp,
1813                                void __user *buffer, size_t *lenp, loff_t *ppos)
1814 {
1815         int op;
1816
1817         if (!capable(CAP_SYS_ADMIN))
1818                 return -EPERM;
1819
1820         op = OP_OR;
1821         return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
1822                                 do_proc_dointvec_bset_conv,&op);
1823 }
1824
1825 struct do_proc_dointvec_minmax_conv_param {
1826         int *min;
1827         int *max;
1828 };
1829
1830 static int do_proc_dointvec_minmax_conv(int *negp, unsigned long *lvalp,
1831                                         int *valp,
1832                                         int write, void *data)
1833 {
1834         struct do_proc_dointvec_minmax_conv_param *param = data;
1835         if (write) {
1836                 int val = *negp ? -*lvalp : *lvalp;
1837                 if ((param->min && *param->min > val) ||
1838                     (param->max && *param->max < val))
1839                         return -EINVAL;
1840                 *valp = val;
1841         } else {
1842                 int val = *valp;
1843                 if (val < 0) {
1844                         *negp = -1;
1845                         *lvalp = (unsigned long)-val;
1846                 } else {
1847                         *negp = 0;
1848                         *lvalp = (unsigned long)val;
1849                 }
1850         }
1851         return 0;
1852 }
1853
1854 /**
1855  * proc_dointvec_minmax - read a vector of integers with min/max values
1856  * @table: the sysctl table
1857  * @write: %TRUE if this is a write to the sysctl file
1858  * @filp: the file structure
1859  * @buffer: the user buffer
1860  * @lenp: the size of the user buffer
1861  * @ppos: file position
1862  *
1863  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
1864  * values from/to the user buffer, treated as an ASCII string.
1865  *
1866  * This routine will ensure the values are within the range specified by
1867  * table->extra1 (min) and table->extra2 (max).
1868  *
1869  * Returns 0 on success.
1870  */
1871 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
1872                   void __user *buffer, size_t *lenp, loff_t *ppos)
1873 {
1874         struct do_proc_dointvec_minmax_conv_param param = {
1875                 .min = (int *) table->extra1,
1876                 .max = (int *) table->extra2,
1877         };
1878         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
1879                                 do_proc_dointvec_minmax_conv, &param);
1880 }
1881
1882 static int __do_proc_doulongvec_minmax(void *data, ctl_table *table, int write,
1883                                      struct file *filp,
1884                                      void __user *buffer,
1885                                      size_t *lenp, loff_t *ppos,
1886                                      unsigned long convmul,
1887                                      unsigned long convdiv)
1888 {
1889 #define TMPBUFLEN 21
1890         unsigned long *i, *min, *max, val;
1891         int vleft, first=1, neg;
1892         size_t len, left;
1893         char buf[TMPBUFLEN], *p;
1894         char __user *s = buffer;
1895
1896         if (!data || !table->maxlen || !*lenp ||
1897             (*ppos && !write)) {
1898                 *lenp = 0;
1899                 return 0;
1900         }
1901
1902         i = (unsigned long *) data;
1903         min = (unsigned long *) table->extra1;
1904         max = (unsigned long *) table->extra2;
1905         vleft = table->maxlen / sizeof(unsigned long);
1906         left = *lenp;
1907
1908         for (; left && vleft--; i++, min++, max++, first=0) {
1909                 if (write) {
1910                         while (left) {
1911                                 char c;
1912                                 if (get_user(c, s))
1913                                         return -EFAULT;
1914                                 if (!isspace(c))
1915                                         break;
1916                                 left--;
1917                                 s++;
1918                         }
1919                         if (!left)
1920                                 break;
1921                         neg = 0;
1922                         len = left;
1923                         if (len > TMPBUFLEN-1)
1924                                 len = TMPBUFLEN-1;
1925                         if (copy_from_user(buf, s, len))
1926                                 return -EFAULT;
1927                         buf[len] = 0;
1928                         p = buf;
1929                         if (*p == '-' && left > 1) {
1930                                 neg = 1;
1931                                 p++;
1932                         }
1933                         if (*p < '0' || *p > '9')
1934                                 break;
1935                         val = simple_strtoul(p, &p, 0) * convmul / convdiv ;
1936                         len = p-buf;
1937                         if ((len < left) && *p && !isspace(*p))
1938                                 break;
1939                         if (neg)
1940                                 val = -val;
1941                         s += len;
1942                         left -= len;
1943
1944                         if(neg)
1945                                 continue;
1946                         if ((min && val < *min) || (max && val > *max))
1947                                 continue;
1948                         *i = val;
1949                 } else {
1950                         p = buf;
1951                         if (!first)
1952                                 *p++ = '\t';
1953                         sprintf(p, "%lu", convdiv * (*i) / convmul);
1954                         len = strlen(buf);
1955                         if (len > left)
1956                                 len = left;
1957                         if(copy_to_user(s, buf, len))
1958                                 return -EFAULT;
1959                         left -= len;
1960                         s += len;
1961                 }
1962         }
1963
1964         if (!write && !first && left) {
1965                 if(put_user('\n', s))
1966                         return -EFAULT;
1967                 left--, s++;
1968         }
1969         if (write) {
1970                 while (left) {
1971                         char c;
1972                         if (get_user(c, s++))
1973                                 return -EFAULT;
1974                         if (!isspace(c))
1975                                 break;
1976                         left--;
1977                 }
1978         }
1979         if (write && first)
1980                 return -EINVAL;
1981         *lenp -= left;
1982         *ppos += *lenp;
1983         return 0;
1984 #undef TMPBUFLEN
1985 }
1986
1987 static int do_proc_doulongvec_minmax(ctl_table *table, int write,
1988                                      struct file *filp,
1989                                      void __user *buffer,
1990                                      size_t *lenp, loff_t *ppos,
1991                                      unsigned long convmul,
1992                                      unsigned long convdiv)
1993 {
1994         return __do_proc_doulongvec_minmax(table->data, table, write,
1995                         filp, buffer, lenp, ppos, convmul, convdiv);
1996 }
1997
1998 /**
1999  * proc_doulongvec_minmax - read a vector of long integers with min/max values
2000  * @table: the sysctl table
2001  * @write: %TRUE if this is a write to the sysctl file
2002  * @filp: the file structure
2003  * @buffer: the user buffer
2004  * @lenp: the size of the user buffer
2005  * @ppos: file position
2006  *
2007  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2008  * values from/to the user buffer, treated as an ASCII string.
2009  *
2010  * This routine will ensure the values are within the range specified by
2011  * table->extra1 (min) and table->extra2 (max).
2012  *
2013  * Returns 0 on success.
2014  */
2015 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2016                            void __user *buffer, size_t *lenp, loff_t *ppos)
2017 {
2018     return do_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos, 1l, 1l);
2019 }
2020
2021 /**
2022  * proc_doulongvec_ms_jiffies_minmax - read a vector of millisecond values with min/max values
2023  * @table: the sysctl table
2024  * @write: %TRUE if this is a write to the sysctl file
2025  * @filp: the file structure
2026  * @buffer: the user buffer
2027  * @lenp: the size of the user buffer
2028  * @ppos: file position
2029  *
2030  * Reads/writes up to table->maxlen/sizeof(unsigned long) unsigned long
2031  * values from/to the user buffer, treated as an ASCII string. The values
2032  * are treated as milliseconds, and converted to jiffies when they are stored.
2033  *
2034  * This routine will ensure the values are within the range specified by
2035  * table->extra1 (min) and table->extra2 (max).
2036  *
2037  * Returns 0 on success.
2038  */
2039 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2040                                       struct file *filp,
2041                                       void __user *buffer,
2042                                       size_t *lenp, loff_t *ppos)
2043 {
2044     return do_proc_doulongvec_minmax(table, write, filp, buffer,
2045                                      lenp, ppos, HZ, 1000l);
2046 }
2047
2048
2049 static int do_proc_dointvec_jiffies_conv(int *negp, unsigned long *lvalp,
2050                                          int *valp,
2051                                          int write, void *data)
2052 {
2053         if (write) {
2054                 if (*lvalp > LONG_MAX / HZ)
2055                         return 1;
2056                 *valp = *negp ? -(*lvalp*HZ) : (*lvalp*HZ);
2057         } else {
2058                 int val = *valp;
2059                 unsigned long lval;
2060                 if (val < 0) {
2061                         *negp = -1;
2062                         lval = (unsigned long)-val;
2063                 } else {
2064                         *negp = 0;
2065                         lval = (unsigned long)val;
2066                 }
2067                 *lvalp = lval / HZ;
2068         }
2069         return 0;
2070 }
2071
2072 static int do_proc_dointvec_userhz_jiffies_conv(int *negp, unsigned long *lvalp,
2073                                                 int *valp,
2074                                                 int write, void *data)
2075 {
2076         if (write) {
2077                 if (USER_HZ < HZ && *lvalp > (LONG_MAX / HZ) * USER_HZ)
2078                         return 1;
2079                 *valp = clock_t_to_jiffies(*negp ? -*lvalp : *lvalp);
2080         } else {
2081                 int val = *valp;
2082                 unsigned long lval;
2083                 if (val < 0) {
2084                         *negp = -1;
2085                         lval = (unsigned long)-val;
2086                 } else {
2087                         *negp = 0;
2088                         lval = (unsigned long)val;
2089                 }
2090                 *lvalp = jiffies_to_clock_t(lval);
2091         }
2092         return 0;
2093 }
2094
2095 static int do_proc_dointvec_ms_jiffies_conv(int *negp, unsigned long *lvalp,
2096                                             int *valp,
2097                                             int write, void *data)
2098 {
2099         if (write) {
2100                 *valp = msecs_to_jiffies(*negp ? -*lvalp : *lvalp);
2101         } else {
2102                 int val = *valp;
2103                 unsigned long lval;
2104                 if (val < 0) {
2105                         *negp = -1;
2106                         lval = (unsigned long)-val;
2107                 } else {
2108                         *negp = 0;
2109                         lval = (unsigned long)val;
2110                 }
2111                 *lvalp = jiffies_to_msecs(lval);
2112         }
2113         return 0;
2114 }
2115
2116 /**
2117  * proc_dointvec_jiffies - read a vector of integers as seconds
2118  * @table: the sysctl table
2119  * @write: %TRUE if this is a write to the sysctl file
2120  * @filp: the file structure
2121  * @buffer: the user buffer
2122  * @lenp: the size of the user buffer
2123  * @ppos: file position
2124  *
2125  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2126  * values from/to the user buffer, treated as an ASCII string.
2127  * The values read are assumed to be in seconds, and are converted into
2128  * jiffies.
2129  *
2130  * Returns 0 on success.
2131  */
2132 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2133                           void __user *buffer, size_t *lenp, loff_t *ppos)
2134 {
2135     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2136                             do_proc_dointvec_jiffies_conv,NULL);
2137 }
2138
2139 /**
2140  * proc_dointvec_userhz_jiffies - read a vector of integers as 1/USER_HZ seconds
2141  * @table: the sysctl table
2142  * @write: %TRUE if this is a write to the sysctl file
2143  * @filp: the file structure
2144  * @buffer: the user buffer
2145  * @lenp: the size of the user buffer
2146  * @ppos: pointer to the file position
2147  *
2148  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2149  * values from/to the user buffer, treated as an ASCII string.
2150  * The values read are assumed to be in 1/USER_HZ seconds, and
2151  * are converted into jiffies.
2152  *
2153  * Returns 0 on success.
2154  */
2155 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2156                                  void __user *buffer, size_t *lenp, loff_t *ppos)
2157 {
2158     return do_proc_dointvec(table,write,filp,buffer,lenp,ppos,
2159                             do_proc_dointvec_userhz_jiffies_conv,NULL);
2160 }
2161
2162 /**
2163  * proc_dointvec_ms_jiffies - read a vector of integers as 1 milliseconds
2164  * @table: the sysctl table
2165  * @write: %TRUE if this is a write to the sysctl file
2166  * @filp: the file structure
2167  * @buffer: the user buffer
2168  * @lenp: the size of the user buffer
2169  * @ppos: file position
2170  * @ppos: the current position in the file
2171  *
2172  * Reads/writes up to table->maxlen/sizeof(unsigned int) integer
2173  * values from/to the user buffer, treated as an ASCII string.
2174  * The values read are assumed to be in 1/1000 seconds, and
2175  * are converted into jiffies.
2176  *
2177  * Returns 0 on success.
2178  */
2179 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2180                              void __user *buffer, size_t *lenp, loff_t *ppos)
2181 {
2182         return do_proc_dointvec(table, write, filp, buffer, lenp, ppos,
2183                                 do_proc_dointvec_ms_jiffies_conv, NULL);
2184 }
2185
2186 static int proc_do_cad_pid(ctl_table *table, int write, struct file *filp,
2187                            void __user *buffer, size_t *lenp, loff_t *ppos)
2188 {
2189         struct pid *new_pid;
2190         pid_t tmp;
2191         int r;
2192
2193         tmp = pid_nr(cad_pid);
2194
2195         r = __do_proc_dointvec(&tmp, table, write, filp, buffer,
2196                                lenp, ppos, NULL, NULL);
2197         if (r || !write)
2198                 return r;
2199
2200         new_pid = find_get_pid(tmp);
2201         if (!new_pid)
2202                 return -ESRCH;
2203
2204         put_pid(xchg(&cad_pid, new_pid));
2205         return 0;
2206 }
2207
2208 #else /* CONFIG_PROC_FS */
2209
2210 int proc_dostring(ctl_table *table, int write, struct file *filp,
2211                   void __user *buffer, size_t *lenp, loff_t *ppos)
2212 {
2213         return -ENOSYS;
2214 }
2215
2216 int proc_dointvec(ctl_table *table, int write, struct file *filp,
2217                   void __user *buffer, size_t *lenp, loff_t *ppos)
2218 {
2219         return -ENOSYS;
2220 }
2221
2222 int proc_dointvec_bset(ctl_table *table, int write, struct file *filp,
2223                         void __user *buffer, size_t *lenp, loff_t *ppos)
2224 {
2225         return -ENOSYS;
2226 }
2227
2228 int proc_dointvec_minmax(ctl_table *table, int write, struct file *filp,
2229                     void __user *buffer, size_t *lenp, loff_t *ppos)
2230 {
2231         return -ENOSYS;
2232 }
2233
2234 int proc_dointvec_jiffies(ctl_table *table, int write, struct file *filp,
2235                     void __user *buffer, size_t *lenp, loff_t *ppos)
2236 {
2237         return -ENOSYS;
2238 }
2239
2240 int proc_dointvec_userhz_jiffies(ctl_table *table, int write, struct file *filp,
2241                     void __user *buffer, size_t *lenp, loff_t *ppos)
2242 {
2243         return -ENOSYS;
2244 }
2245
2246 int proc_dointvec_ms_jiffies(ctl_table *table, int write, struct file *filp,
2247                              void __user *buffer, size_t *lenp, loff_t *ppos)
2248 {
2249         return -ENOSYS;
2250 }
2251
2252 int proc_doulongvec_minmax(ctl_table *table, int write, struct file *filp,
2253                     void __user *buffer, size_t *lenp, loff_t *ppos)
2254 {
2255         return -ENOSYS;
2256 }
2257
2258 int proc_doulongvec_ms_jiffies_minmax(ctl_table *table, int write,
2259                                       struct file *filp,
2260                                       void __user *buffer,
2261                                       size_t *lenp, loff_t *ppos)
2262 {
2263     return -ENOSYS;
2264 }
2265
2266
2267 #endif /* CONFIG_PROC_FS */
2268
2269
2270 #ifdef CONFIG_SYSCTL_SYSCALL
2271 /*
2272  * General sysctl support routines
2273  */
2274
2275 /* The generic string strategy routine: */
2276 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2277                   void __user *oldval, size_t __user *oldlenp,
2278                   void __user *newval, size_t newlen)
2279 {
2280         if (!table->data || !table->maxlen)
2281                 return -ENOTDIR;
2282
2283         if (oldval && oldlenp) {
2284                 size_t bufsize;
2285                 if (get_user(bufsize, oldlenp))
2286                         return -EFAULT;
2287                 if (bufsize) {
2288                         size_t len = strlen(table->data), copied;
2289
2290                         /* This shouldn't trigger for a well-formed sysctl */
2291                         if (len > table->maxlen)
2292                                 len = table->maxlen;
2293
2294                         /* Copy up to a max of bufsize-1 bytes of the string */
2295                         copied = (len >= bufsize) ? bufsize - 1 : len;
2296
2297                         if (copy_to_user(oldval, table->data, copied) ||
2298                             put_user(0, (char __user *)(oldval + copied)))
2299                                 return -EFAULT;
2300                         if (put_user(len, oldlenp))
2301                                 return -EFAULT;
2302                 }
2303         }
2304         if (newval && newlen) {
2305                 size_t len = newlen;
2306                 if (len > table->maxlen)
2307                         len = table->maxlen;
2308                 if(copy_from_user(table->data, newval, len))
2309                         return -EFAULT;
2310                 if (len == table->maxlen)
2311                         len--;
2312                 ((char *) table->data)[len] = 0;
2313         }
2314         return 1;
2315 }
2316
2317 /*
2318  * This function makes sure that all of the integers in the vector
2319  * are between the minimum and maximum values given in the arrays
2320  * table->extra1 and table->extra2, respectively.
2321  */
2322 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2323                 void __user *oldval, size_t __user *oldlenp,
2324                 void __user *newval, size_t newlen)
2325 {
2326
2327         if (newval && newlen) {
2328                 int __user *vec = (int __user *) newval;
2329                 int *min = (int *) table->extra1;
2330                 int *max = (int *) table->extra2;
2331                 size_t length;
2332                 int i;
2333
2334                 if (newlen % sizeof(int) != 0)
2335                         return -EINVAL;
2336
2337                 if (!table->extra1 && !table->extra2)
2338                         return 0;
2339
2340                 if (newlen > table->maxlen)
2341                         newlen = table->maxlen;
2342                 length = newlen / sizeof(int);
2343
2344                 for (i = 0; i < length; i++) {
2345                         int value;
2346                         if (get_user(value, vec + i))
2347                                 return -EFAULT;
2348                         if (min && value < min[i])
2349                                 return -EINVAL;
2350                         if (max && value > max[i])
2351                                 return -EINVAL;
2352                 }
2353         }
2354         return 0;
2355 }
2356
2357 /* Strategy function to convert jiffies to seconds */
2358 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2359                 void __user *oldval, size_t __user *oldlenp,
2360                 void __user *newval, size_t newlen)
2361 {
2362         if (oldval && oldlenp) {
2363                 size_t olen;
2364
2365                 if (get_user(olen, oldlenp))
2366                         return -EFAULT;
2367                 if (olen) {
2368                         int val;
2369
2370                         if (olen < sizeof(int))
2371                                 return -EINVAL;
2372
2373                         val = *(int *)(table->data) / HZ;
2374                         if (put_user(val, (int __user *)oldval))
2375                                 return -EFAULT;
2376                         if (put_user(sizeof(int), oldlenp))
2377                                 return -EFAULT;
2378                 }
2379         }
2380         if (newval && newlen) {
2381                 int new;
2382                 if (newlen != sizeof(int))
2383                         return -EINVAL;
2384                 if (get_user(new, (int __user *)newval))
2385                         return -EFAULT;
2386                 *(int *)(table->data) = new*HZ;
2387         }
2388         return 1;
2389 }
2390
2391 /* Strategy function to convert jiffies to seconds */
2392 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2393                 void __user *oldval, size_t __user *oldlenp,
2394                 void __user *newval, size_t newlen)
2395 {
2396         if (oldval && oldlenp) {
2397                 size_t olen;
2398
2399                 if (get_user(olen, oldlenp))
2400                         return -EFAULT;
2401                 if (olen) {
2402                         int val;
2403
2404                         if (olen < sizeof(int))
2405                                 return -EINVAL;
2406
2407                         val = jiffies_to_msecs(*(int *)(table->data));
2408                         if (put_user(val, (int __user *)oldval))
2409                                 return -EFAULT;
2410                         if (put_user(sizeof(int), oldlenp))
2411                                 return -EFAULT;
2412                 }
2413         }
2414         if (newval && newlen) {
2415                 int new;
2416                 if (newlen != sizeof(int))
2417                         return -EINVAL;
2418                 if (get_user(new, (int __user *)newval))
2419                         return -EFAULT;
2420                 *(int *)(table->data) = msecs_to_jiffies(new);
2421         }
2422         return 1;
2423 }
2424
2425
2426
2427 #else /* CONFIG_SYSCTL_SYSCALL */
2428
2429
2430 asmlinkage long sys_sysctl(struct __sysctl_args __user *args)
2431 {
2432         static int msg_count;
2433         struct __sysctl_args tmp;
2434         int name[CTL_MAXNAME];
2435         int i;
2436
2437         /* Read in the sysctl name for better debug message logging */
2438         if (copy_from_user(&tmp, args, sizeof(tmp)))
2439                 return -EFAULT;
2440         if (tmp.nlen <= 0 || tmp.nlen >= CTL_MAXNAME)
2441                 return -ENOTDIR;
2442         for (i = 0; i < tmp.nlen; i++)
2443                 if (get_user(name[i], tmp.name + i))
2444                         return -EFAULT;
2445
2446         /* Ignore accesses to kernel.version */
2447         if ((tmp.nlen == 2) && (name[0] == CTL_KERN) && (name[1] == KERN_VERSION))
2448                 goto out;
2449
2450         if (msg_count < 5) {
2451                 msg_count++;
2452                 printk(KERN_INFO
2453                         "warning: process `%s' used the removed sysctl "
2454                         "system call with ", current->comm);
2455                 for (i = 0; i < tmp.nlen; i++)
2456                         printk("%d.", name[i]);
2457                 printk("\n");
2458         }
2459 out:
2460         return -ENOSYS;
2461 }
2462
2463 int sysctl_string(ctl_table *table, int __user *name, int nlen,
2464                   void __user *oldval, size_t __user *oldlenp,
2465                   void __user *newval, size_t newlen)
2466 {
2467         return -ENOSYS;
2468 }
2469
2470 int sysctl_intvec(ctl_table *table, int __user *name, int nlen,
2471                 void __user *oldval, size_t __user *oldlenp,
2472                 void __user *newval, size_t newlen)
2473 {
2474         return -ENOSYS;
2475 }
2476
2477 int sysctl_jiffies(ctl_table *table, int __user *name, int nlen,
2478                 void __user *oldval, size_t __user *oldlenp,
2479                 void __user *newval, size_t newlen)
2480 {
2481         return -ENOSYS;
2482 }
2483
2484 int sysctl_ms_jiffies(ctl_table *table, int __user *name, int nlen,
2485                 void __user *oldval, size_t __user *oldlenp,
2486                 void __user *newval, size_t newlen)
2487 {
2488         return -ENOSYS;
2489 }
2490
2491 #endif /* CONFIG_SYSCTL_SYSCALL */
2492
2493 /*
2494  * No sense putting this after each symbol definition, twice,
2495  * exception granted :-)
2496  */
2497 EXPORT_SYMBOL(proc_dointvec);
2498 EXPORT_SYMBOL(proc_dointvec_jiffies);
2499 EXPORT_SYMBOL(proc_dointvec_minmax);
2500 EXPORT_SYMBOL(proc_dointvec_userhz_jiffies);
2501 EXPORT_SYMBOL(proc_dointvec_ms_jiffies);
2502 EXPORT_SYMBOL(proc_dostring);
2503 EXPORT_SYMBOL(proc_doulongvec_minmax);
2504 EXPORT_SYMBOL(proc_doulongvec_ms_jiffies_minmax);
2505 EXPORT_SYMBOL(register_sysctl_table);
2506 EXPORT_SYMBOL(sysctl_intvec);
2507 EXPORT_SYMBOL(sysctl_jiffies);
2508 EXPORT_SYMBOL(sysctl_ms_jiffies);
2509 EXPORT_SYMBOL(sysctl_string);
2510 EXPORT_SYMBOL(unregister_sysctl_table);