src/afs/LINUX/osi_probe.c

   1 /*
   2  * vi:set cin noet sw=4 tw=70:
   3  * Copyright 2004, International Business Machines Corporation and others.
   4  * All Rights Reserved.
   5  *
   6  * This software has been released under the terms of the IBM Public
   7  * License.  For details, see the LICENSE file in the top-level source
   8  * directory or online at http://www.openafs.org/dl/license10.html
   9  *
  10  * Portions of this code borrowed from arla under the following terms:
  11  * Copyright (c) 2003-2004 Kungliga Tekniska Högskolan
  12  * (Royal Institute of Technology, Stockholm, Sweden).
  13  * All rights reserved.
  14  *
  15  * Redistribution and use in source and binary forms, with or without
  16  * modification, are permitted provided that the following conditions
  17  * are met:
  18  *
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  *
  22  * 2. Redistributions in binary form must reproduce the above copyright
  23  *    notice, this list of conditions and the following disclaimer in the
  24  *    documentation and/or other materials provided with the distribution.
  25  *
  26  * 3. Neither the name of the Institute nor the names of its contributors
  27  *    may be used to endorse or promote products derived from this software
  28  *    without specific prior written permission.
  29  *
  30  * Alternatively, this software may be distributed under the terms of the
  31  * GNU General Public License ("GPL").
  32  *
  33  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  34  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  35  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  36  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  37  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  38  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  39  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  40  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  41  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  42  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  43  * SUCH DAMAGE.
  44  */
  45
  46 /* Code to find the Linux syscall table */
  47
  48 #ifdef OSI_PROBE_STANDALONE
  49 # define OSI_PROBE_DEBUG
  50 #endif
  51 #ifndef OSI_PROBE_STANDALONE
  52 # include <afsconfig.h>
  53 # include "afs/param.h"
  54 #endif
  55
  56 #include <linux/version.h>
  57 #if defined(ENABLE_LINUX_SYSCALL_PROBING)
  58 #include <linux/module.h> /* early to avoid printf->printk mapping */
  59 #include <scsi/scsi.h> /* for scsi_command_size */
  60 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
  61 /* Slightly kludgy, but too bad */
  62 #define scsi_command_size scsi_command_size_tbl
  63 #endif
  64 #ifndef OSI_PROBE_STANDALONE
  65 # include "afs/sysincludes.h"
  66 # include "afsincludes.h"
  67 #endif
  68 #include <linux/sched.h>
  69 #ifdef HAVE_LINUX_CONFIG_H
  70 # include <linux/config.h>
  71 #endif
  72 #include <linux/linkage.h>
  73 #include <linux/init.h>
  74 #include <linux/unistd.h>
  75 #include <linux/mm.h>
  76
  77 #if defined(AFS_PPC64_LINUX26_ENV)
  78 # include <asm/abs_addr.h>
  79 #endif
  80
  81 #ifdef AFS_AMD64_LINUX20_ENV
  82 # include <asm/ia32_unistd.h>
  83 #endif
  84
  85 /* number of syscalls */
  86 /* NB: on MIPS we care about the 4xxx range */
  87 #ifndef NR_syscalls
  88 #define NR_syscalls 222
  89 #endif
  90
  91 /* lower bound of valid kernel text pointers */
  92 #ifdef AFS_IA64_LINUX20_ENV
  93 #define ktxt_lower_bound (((unsigned long)&kernel_thread )  & 0xfff00000L)
  94 #elif defined(AFS_PPC64_LINUX20_ENV)
  95 #define ktxt_lower_bound (KERNELBASE)
  96 #else
  97 #define ktxt_lower_bound (((unsigned long)&kernel_thread )  & ~0xfffffL)
  98 #endif
  99
 100 /* On SPARC64 and S390X, sys_call_table contains 32-bit entries
 101  * even though pointers are 64 bit quantities.
 102  */
 103 #if defined(AFS_SPARC64_LINUX20_ENV) || defined(AFS_S390X_LINUX24_ENV)
 104 #define SYSCALLTYPE unsigned int
 105 #define PROBETYPE int
 106 #else
 107 #define SYSCALLTYPE void *
 108 #define PROBETYPE long
 109 #endif
 110
 111 #if defined(AFS_S390X_LINUX20_ENV) && !defined(AFS_S390X_LINUX26_ENV)
 112 #define _SS(x) ((x) << 1)
 113 #define _SX(x) ((x) &~ 1)
 114 #else
 115 #define _SS(x) (x)
 116 #define _SX(x) (x)
 117 #endif
 118
 119 /* Older Linux doesn't have __user. The sys_read prototype needs it. */
 120 #ifndef __user
 121 #define __user
 122 #endif
 123
 124 /* Allow the user to specify sys_call_table addresses */
 125 static unsigned long sys_call_table_addr[4] = { 0,0,0,0 };
 126 #if defined(module_param_array) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 127 module_param_array(sys_call_table_addr, long, NULL, 0);
 128 #else
 129 MODULE_PARM(sys_call_table_addr, "1-4l");
 130 #endif
 131 MODULE_PARM_DESC(sys_call_table_addr, "Location of system call tables");
 132
 133 /* If this is set, we are more careful about avoiding duplicate matches */
 134 static int probe_carefully = 1;
 135 #if defined(module_param) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 136 module_param(probe_carefully, int, 0);
 137 #else
 138 MODULE_PARM(probe_carefully, "i");
 139 #endif
 140 MODULE_PARM_DESC(probe_carefully, "Probe for system call tables carefully");
 141
 142 static int probe_ignore_syscalls[8] = { -1, -1, -1, -1, -1, -1, -1, -1 };
 143 #if defined(module_param_array) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 144 module_param_array(probe_ignore_syscalls, int, NULL, 0);
 145 #else
 146 MODULE_PARM(probe_ignore_syscalls, "1-8i");
 147 #endif
 148 MODULE_PARM_DESC(probe_ignore_syscalls, "Syscalls to ignore in table checks");
 149
 150 #ifdef OSI_PROBE_DEBUG
 151 /*
 152  * Debugging flags:
 153  * 0x0001 - General debugging
 154  * 0x0002 - detail - try
 155  * 0x0004 - detail - try_harder
 156  * 0x0008 - detail - check_table
 157  * 0x0010 - detail - check_harder
 158  * 0x0020 - detail - check_harder/zapped
 159  * 0x0040 - automatically ignore setgroups and afs_syscall
 160  * 0x0080 - detail - check_table_readable
 161  */
 162 static int probe_debug = 0x41;
 163 #if defined(module_param) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 164 module_param(probe_debug, int, 0);
 165 #else
 166 MODULE_PARM(probe_debug, "i");
 167 #endif
 168 MODULE_PARM_DESC(probe_debug, "Debugging level");
 169
 170 static unsigned long probe_debug_addr[4] = { 0,0,0,0 };
 171 #if defined(module_param_array) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 172 module_param_array(probe_debug_addr, long, NULL, 0);
 173 #else
 174 MODULE_PARM(probe_debug_addr, "1-4l");
 175 #endif
 176 MODULE_PARM_DESC(probe_debug_addr, "Debug range starting locations");
 177
 178 static unsigned long probe_debug_range = 0;
 179 #if defined(module_param) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 180 module_param(probe_debug_range, long, 0);
 181 #else
 182 MODULE_PARM(probe_debug_range, "l");
 183 #endif
 184 MODULE_PARM_DESC(probe_debug_range, "Debug range length");
 185
 186 static unsigned long probe_debug_tag = 0;
 187 #if defined(module_param) && LINUX_VERSION_CODE > KERNEL_VERSION(2,6,9)
 188 module_param(probe_debug_tag, long, 0);
 189 #else
 190 MODULE_PARM(probe_debug_tag, "l");
 191 #endif
 192 MODULE_PARM_DESC(probe_debug_tag, "Debugging output start tag");
 193 #endif
 194
 195
 196 /* Weak references are our friends.  They are supported by the in-kernel
 197  * linker in Linux 2.6 and by all versions of modutils back to 2.2pre1.
 198  * A weak reference not satisified by the kernel will have value zero.
 199  *
 200  * Unfortunately, weak references to functions don't work right on
 201  * IA64; specifically, if you actually try to make a call through
 202  * such a reference, and the symbol doesn't exist in the kernel, then
 203  * the module relocation code will oops.  A workaround for this is
 204  * probably possible, but the use of kallsyms_* is of limited value,
 205  * so I'm not bothing with the effort for now.
 206  * -- jhutz, 10-Feb-2005
 207  */
 208 #ifdef OSI_PROBE_KALLSYMS
 209 extern int kallsyms_symbol_to_address(char *name, unsigned long *token,
 210                                       char **mod_name,
 211                                       unsigned long *mod_start,
 212                                       unsigned long *mod_end,
 213                                       char **sec_name,
 214                                       unsigned long *sec_start,
 215                                       unsigned long *sec_end,
 216                                       char **sym_name,
 217                                       unsigned long *sym_start,
 218                                       unsigned long *sym_end
 219                                      ) __attribute__((weak));
 220
 221 extern int kallsyms_address_to_symbol(unsigned long address,
 222                                       char **mod_name,
 223                                       unsigned long *mod_start,
 224                                       unsigned long *mod_end,
 225                                       char **sec_name,
 226                                       unsigned long *sec_start,
 227                                       unsigned long *sec_end,
 228                                       char **sym_name,
 229                                       unsigned long *sym_start,
 230                                       unsigned long *sym_end
 231                                      ) __attribute__((weak));
 232 #endif
 233
 234 extern SYSCALLTYPE sys_call_table[] __attribute__((weak));
 235 extern SYSCALLTYPE ia32_sys_call_table[] __attribute__((weak));
 236 extern SYSCALLTYPE sys_call_table32[] __attribute__((weak));
 237 extern SYSCALLTYPE sys_call_table_emu[] __attribute__((weak));
 238
 239 extern asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count) __attribute__((weak));
 240 extern asmlinkage long sys_close(unsigned int) __attribute__((weak));
 241 #if defined(EXPORTED_SYS_CHDIR)
 242 extern asmlinkage long sys_chdir(const char *) __attribute__((weak));
 243 #endif
 244 extern asmlinkage ssize_t sys_write(unsigned int, const char *, size_t) __attribute__((weak));
 245 extern asmlinkage long sys_wait4(pid_t, int *, int, struct rusage *) __attribute__((weak));
 246 extern asmlinkage long sys_exit (int) __attribute__((weak));
 247 #if defined(EXPORTED_SYS_OPEN)
 248 extern asmlinkage long sys_open (const char *, int, int) __attribute__((weak));
 249 #endif
 250 extern asmlinkage long sys_ioctl(unsigned int, unsigned int, unsigned long) __attribute__((weak));
 251
 252
 253 /* Structures used to control probing.  We put all the details of which
 254  * symbols we're interested in, what syscall functions to look for, etc
 255  * into tables, so we can then have a single copy of the functions that
 256  * actually do the work.
 257  */
 258 typedef struct {
 259     char *name;
 260     int NR1;
 261     void *fn1;
 262     int NR2;
 263     void *fn2;
 264     int NR3;
 265     void *fn3;
 266 } tryctl;
 267
 268 typedef struct {
 269     char *symbol;                   /* symbol name */
 270     char *desc;                     /* description for messages */
 271     int offset;                     /* first syscall number in table */
 272
 273     void *weak_answer;              /* weak symbol ref */
 274     void *parm_answer;              /* module parameter answer */
 275     void *debug_answer;             /* module parameter answer */
 276     unsigned long given_answer;     /* compiled-in answer, if any */
 277
 278     tryctl *trylist;                /* array of combinations to try */
 279
 280     unsigned long try_sect_sym;     /* symbol in section to try scanning */
 281     unsigned long try_base;         /* default base address for scan */
 282     unsigned long try_base_mask;    /* base address bits to force to zero */
 283     unsigned long try_length;       /* default length for scan */
 284
 285     unsigned long alt_try_sect_sym;     /* symbol in section to try scanning */
 286     unsigned long alt_try_base;         /* default base address for scan */
 287     unsigned long alt_try_base_mask;    /* base address bits to force to zero */
 288     unsigned long alt_try_length;       /* default length for scan */
 289
 290     int n_zapped_syscalls;          /* number of unimplemented system calls */
 291     int *zapped_syscalls;           /* list of unimplemented system calls */
 292
 293     int n_unique_syscalls;          /* number of unique system calls */
 294     int *unique_syscalls;           /* list of unimplemented system calls */
 295
 296     int verifyNR;                   /* syscall number to verify match */
 297     void *verify_fn;                /* syscall pointer to verify match */
 298
 299     int debug_ignore_NR[4];         /* syscalls to ignore for debugging */
 300 } probectl;
 301
 302 #if defined(AFS_I386_LINUX26_ENV) || defined(AFS_AMD64_LINUX26_ENV)
 303 static int check_access(unsigned long, int);
 304 static int check_table_readable(probectl *, PROBETYPE *);
 305 #endif
 306
 307
 308 /********** Probing Configuration: sys_call_table **********/
 309
 310 /* syscall pairs/triplets to probe */
 311 /* On PPC64 and SPARC64, we need to omit the ones that might match both tables */
 312 static tryctl main_try[] = {
 313 #if !defined(AFS_PPC64_LINUX20_ENV) && !defined(AFS_SPARC64_LINUX20_ENV)
 314 #if defined(EXPORTED_SYS_CHDIR)
 315     { "scan: close+chdir+write", __NR_close, &sys_close, __NR_chdir, &sys_chdir, __NR_write, &sys_write },
 316 #endif
 317 #endif
 318     { "scan: close+wait4",       __NR_close, &sys_close, __NR_wait4, &sys_wait4, -1,         0          },
 319 #if !defined(AFS_PPC64_LINUX20_ENV) && !defined(AFS_SPARC64_LINUX20_ENV)
 320 #if defined(EXPORTED_SYS_CHDIR)
 321     { "scan: close+chdir",       __NR_close, &sys_close, __NR_chdir, &sys_chdir, -1,         0          },
 322 #endif
 323 #endif
 324     { "scan: close+ioctl",       __NR_close, &sys_close, __NR_ioctl, &sys_ioctl, -1,         0          },
 325 #if defined(EXPORTED_SYS_OPEN)
 326     { "scan: exit+open",         __NR_exit,  &sys_exit,  __NR_open,  &sys_open,  -1,         0          },
 327 #endif
 328     { 0 }
 329 };
 330
 331 /* zapped syscalls for try_harder */
 332 /* this list is based on the table in 'zapped_syscalls' */
 333
 334 static int main_zapped_syscalls[] = {
 335 /*
 336  * SPARC-Linux uses syscall number mappings chosen to be compatible
 337  * with SunOS.  So, it doesn't have any of the traditional calls or
 338  * the new STREAMS ones.  However, there are a number of syscalls
 339  * which are SunOS-specific (not implemented on Linux), i386-specific
 340  * (not implemented on SPARC-Linux), or implemented only on one of
 341  * sparc32 or sparc64.  Of course, there are no __NR macros for most
 342  * of these.
 343  *
 344  * Note that the calls we list here are implemented by sys_nis_syscall,
 345  * not by sys_ni_syscall.  That means we have to exclude all of the
 346  * other entries, or we might get a sys_ni_syscall into the list and
 347  * the test would no longer work.
 348  */
 349 #if defined(AFS_SPARC64_LINUX20_ENV)
 350     /* mmap2, fstat64, getmsg, putmsg, modify_ldt */
 351     56, 63, 151, 152, 218,
 352 #elif defined(AFS_SPARC_LINUX20_ENV)
 353     /* memory_ordering, getmsg, putmsg, unimplemented, modify_ldt */
 354     52, 151, 152, 164, 218,
 355 #else /* !AFS_SPARC_LINUX20_ENV */
 356
 357 /*
 358  * These 7 syscalls are present in the syscall table on most "older"
 359  * platforms that use the traditional syscall number mappings.  They
 360  * are not implemented on any platform.
 361  */
 362 #ifdef __NR_break
 363     __NR_break,
 364 #endif
 365 #ifdef __NR_stty
 366     __NR_stty,
 367 #endif
 368 #ifdef __NR_gtty
 369     __NR_gtty,
 370 #endif
 371 #ifdef __NR_ftime
 372     __NR_ftime,
 373 #endif
 374 #ifdef __NR_prof
 375     __NR_prof,
 376 #endif
 377 #ifdef __NR_lock
 378     __NR_lock,
 379 #endif
 380 #ifdef __NR_mpx
 381     __NR_mpx,
 382 #endif
 383 /*
 384  * On s390 and arm (but not arm26), the seven traditional unimplemented
 385  * system calls are indeed present and unimplemented.  However, the
 386  * corresponding __NR macros are not defined, so the tests above fail.
 387  * Instead, we just have to know the numbers for these.
 388  */
 389 #if defined(AFS_S390_LINUX20_ENV) || defined(AFS_S390X_LINUX20_ENV)
 390     /* break, stty, gtty, ftime, prof, lock, mpx */
 391     17, 31, 32, 35, 44, 53, 56,
 392 #endif
 393
 394 /*
 395  * Sadly, some newer platforms like IA64, amd64, and PA-RISC don't have
 396  * the traditional numbers, so the list above are not helpful.  They
 397  * do have entries for getpmsg/putpmsg, which are always unimplemented.
 398  */
 399 #ifdef __NR_getpmsg
 400     __NR_getpmsg,
 401 #endif
 402 #ifdef __NR_putpmsg
 403     __NR_putpmsg,
 404 #endif
 405
 406 /*
 407  * The module-loading mechanism changed in Linux 2.6, and insmod's
 408  * loss is our gain: three new unimplemented system calls!
 409  */
 410 #ifdef __NR_
 411     __NR_create_module,
 412 #endif
 413 #ifdef __NR_query_module
 414     __NR_query_module,
 415 #endif
 416 #ifdef __NR_get_kernel_syms
 417     __NR_get_kernel_syms,
 418 #endif
 419
 420 /*
 421  * On IA64, the old module-loading calls are indeed present and
 422  * unimplemented, but the __NR macros are not defined.  Again,
 423  * we simply have to know their numbers.
 424  */
 425 #ifdef AFS_IA64_LINUX26_ENV
 426     /* create_module, query_module, get_kernel_sysms */
 427     1132, 1136, 1135,
 428 #endif
 429
 430 /* And the same deal for arm (not arm26), if we ever support that. */
 431 #if 0
 432     /* create_module, query_module, get_kernel_sysms */
 433     127, 167, 130,
 434 #endif
 435
 436 /*
 437  * Alpha-Linux uses syscall number mappings chosen to be compatible
 438  * with OSF/1.  So, it doesn't have any of the traditional calls or
 439  * the new STREAMS ones, but it does have several OSF/1-specific
 440  * syscalls which are not implemented on Linux.  These don't exist on
 441  * any other platform.
 442  */
 443 #ifdef __NR_osf_syscall
 444     __NR_osf_syscall,
 445 #endif
 446 #ifdef __NR_osf_profil
 447     __NR_osf_profil,
 448 #endif
 449 #ifdef __NR_osf_reboot
 450     __NR_osf_reboot,
 451 #endif
 452 #ifdef __NR_osf_kmodcall
 453     __NR_osf_kmodcall,
 454 #endif
 455 #ifdef __NR_osf_old_vtrace
 456     __NR_osf_old_vtrace,
 457 #endif
 458
 459 /*
 460  * On PPC64, we need a couple more entries to distinguish the two
 461  * tables, since the system call numbers are the same and the sets of
 462  * unimplemented calls are very similar.
 463  * mmap2 and fstat64 are implemented only for 32-bit calls
 464  */
 465 #ifdef AFS_PPC64_LINUX20_ENV
 466     /* _mmap2, _fstat64 */
 467     192, 197,
 468 #endif /* AFS_PPC64_LINUX20_ENV */
 469
 470 /* Similarly for S390X, with lcown16 and fstat64 */
 471 #ifdef AFS_S390X_LINUX20_ENV
 472     /* lchown16, fstat64 */
 473     16, 197,
 474 #endif
 475 #endif /* !AFS_SPARC_LINUX20_ENV */
 476     0
 477 };
 478
 479 /* unique syscalls for try_harder */
 480 static int main_unique_syscalls[] = {
 481 #if defined(AFS_SPARC64_LINUX24_ENV) || defined(AFS_SPARC_LINUX24_ENV)
 482     /*
 483      * On SPARC, we need some additional unique calls to make sure
 484      * we don't match the SunOS-compatibility table.
 485      */
 486     __NR_sgetmask, __NR_ssetmask,
 487 #endif
 488     __NR_exit, __NR_mount, __NR_read, __NR_write,
 489     __NR_open, __NR_close, __NR_unlink
 490 };
 491
 492 /* probe control structure */
 493 static probectl main_probe = {
 494     /* symbol name and description */
 495     "sys_call_table",
 496     "system call table",
 497
 498     /* syscall number of first entry in table */
 499 #ifdef AFS_IA64_LINUX20_ENV
 500     1024,
 501 #else
 502     0,
 503 #endif
 504
 505     sys_call_table,               /* weak symbol ref */
 506     0, 0,                         /* module parameter answers */
 507 #ifdef AFS_LINUX_sys_call_table
 508     AFS_LINUX_sys_call_table,     /* compiled-in answer, if any */
 509 #else
 510     0,
 511 #endif
 512
 513     main_try,                     /* array of combinations to try */
 514
 515     /* symbol in section to try scanning */
 516 #if defined(AFS_SPARC64_LINUX20_ENV) || defined(AFS_S390_LINUX20_ENV) || defined(AFS_S390X_LINUX20_ENV)
 517     (unsigned long)&sys_close,
 518 #elif defined(AFS_AMD64_LINUX26_ENV)
 519     /* On this platform, it's in a different section! */
 520     (unsigned long)&generic_ro_fops,
 521 #else
 522     (unsigned long)&init_mm,
 523 #endif
 524
 525     /* default base address for scan */
 526     /* base address bits to force to zero */
 527     /* default length for scan */
 528 #if   defined(AFS_SPARC64_LINUX20_ENV)
 529     (unsigned long)(&sys_close),
 530     0xfffff,
 531     0x10000,
 532 #elif   defined(AFS_S390_LINUX20_ENV) || defined(AFS_S390X_LINUX20_ENV)
 533     /* bleah; this is so suboptimal */
 534     (unsigned long)(&sys_close),
 535     0xfffff,
 536     0x20000,
 537 #elif   defined(AFS_IA64_LINUX20_ENV)
 538     (unsigned long)(&init_mm),
 539     0x1fffff,
 540     0x30000,
 541 #elif defined(AFS_AMD64_LINUX26_ENV)
 542     (unsigned long)(&generic_ro_fops) - 0x30000,
 543     0,
 544     0x6000,
 545 #elif defined(AFS_PPC64_LINUX26_ENV)
 546     (unsigned long)(&do_signal),
 547     0xfff,
 548     0x400,
 549 #else
 550     (unsigned long)&init_mm,
 551     0,
 552     16384,
 553 #endif
 554
 555     (unsigned long)scsi_command_size,
 556     (unsigned long)scsi_command_size - 0x10000,
 557     0x3ffff,
 558     0x40000,
 559
 560     /* number and list of unimplemented system calls */
 561     ((sizeof(main_zapped_syscalls)/sizeof(main_zapped_syscalls[0])) - 1),
 562     main_zapped_syscalls,
 563
 564     /* number and list of unique system calls */
 565     (sizeof(main_unique_syscalls)/sizeof(main_unique_syscalls[0])),
 566     main_unique_syscalls,
 567
 568     /* syscall number and pointer to verify match */
 569     __NR_close, &sys_close,
 570
 571     /* syscalls to ignore for debugging */
 572     {
 573 #if   defined(AFS_ALPHA_LINUX20_ENV)
 574         338,
 575 #elif defined(AFS_AMD64_LINUX20_ENV)
 576         183,
 577 #elif defined(AFS_IA64_LINUX20_ENV)
 578         1141,
 579 #elif defined(AFS_SPARC_LINUX20_ENV) || defined(AFS_SPARC64_LINUX20_ENV)
 580         227,
 581 #else
 582         137,
 583 #endif
 584         __NR_setgroups,
 585 #ifdef __NR_setgroups32
 586         __NR_setgroups32,
 587 #else
 588         -1,
 589 #endif
 590         -1,
 591     }
 592 };
 593
 594
 595 /********** Probing Configuration: amd64 ia32_sys_call_table **********/
 596 #if defined(AFS_AMD64_LINUX20_ENV)
 597
 598 /* syscall pairs/triplets to probe */
 599 static tryctl ia32_try[] = {
 600 #if defined(EXPORTED_SYS_CHDIR)
 601     { "scan: close+chdir+write", __NR_ia32_close, &sys_close, __NR_ia32_chdir, &sys_chdir,        __NR_ia32_write, &sys_write },
 602     { "scan: close+chdir",       __NR_ia32_close, &sys_close, __NR_ia32_chdir, &sys_chdir,        -1,              0          },
 603 #endif
 604     { 0 }
 605 };
 606
 607 /* zapped syscalls for try_harder */
 608 static int ia32_zapped_syscalls[] = {
 609     __NR_ia32_break, __NR_ia32_stty, __NR_ia32_gtty, __NR_ia32_ftime,
 610     __NR_ia32_prof,  __NR_ia32_lock, __NR_ia32_mpx,
 611     0
 612 };
 613
 614 /* unique syscalls for try_harder */
 615 static int ia32_unique_syscalls[] = {
 616     __NR_ia32_exit, __NR_ia32_mount, __NR_ia32_read, __NR_ia32_write,
 617     __NR_ia32_open, __NR_ia32_close, __NR_ia32_unlink
 618 };
 619
 620 /* probe control structure */
 621 static probectl ia32_probe = {
 622     /* symbol name and description */
 623     "ia32_sys_call_table",
 624     "32-bit system call table",
 625
 626     /* syscall number of first entry in table */
 627     0,
 628
 629     ia32_sys_call_table,          /* weak symbol ref */
 630     0, 0,                         /* module parameter answers */
 631 #ifdef AFS_LINUX_ia32_sys_call_table
 632     AFS_LINUX_ia32_sys_call_table,/* compiled-in answer, if any */
 633 #else
 634     0,
 635 #endif
 636
 637     ia32_try,                     /* array of combinations to try */
 638
 639     /* symbol in section to try scanning */
 640     (unsigned long)&init_mm,
 641
 642     /* default base address for scan */
 643     /* base address bits to force to zero */
 644     /* default length for scan */
 645     (unsigned long)&init_mm,
 646     0,
 647     (0x180000 / sizeof(unsigned long *)),
 648
 649     (unsigned long)scsi_command_size,
 650     (unsigned long)scsi_command_size - 0x10000,
 651     0x3ffff,
 652     0x40000,
 653
 654
 655     /* number and list of unimplemented system calls */
 656     ((sizeof(ia32_zapped_syscalls)/sizeof(ia32_zapped_syscalls[0])) - 1),
 657     ia32_zapped_syscalls,
 658
 659     /* number and list of unique system calls */
 660     (sizeof(ia32_unique_syscalls)/sizeof(ia32_unique_syscalls[0])),
 661     ia32_unique_syscalls,
 662
 663     /* syscall number and pointer to verify match */
 664     __NR_ia32_close, &sys_close,
 665
 666     /* syscalls to ignore for debugging */
 667     {
 668         137,
 669         __NR_ia32_setgroups,
 670         __NR_ia32_setgroups32,
 671         -1,
 672     }
 673 };
 674
 675 static probectl *probe_list[] = {
 676     &main_probe, &ia32_probe
 677 };
 678
 679
 680 /********** Probing Configuration: IA64 **********/
 681 #elif defined(AFS_IA64_LINUX20_ENV)
 682 struct fptr {
 683     void *ip;
 684     unsigned long gp;
 685 };
 686
 687 /* no 32-bit support on IA64 for now */
 688 static probectl *probe_list[] = {
 689     &main_probe
 690 };
 691
 692
 693 /********** Probing Configuration: ppc64, sparc64 sys_call_table32 **********/
 694 #elif defined(AFS_PPC64_LINUX20_ENV) || defined(AFS_SPARC64_LINUX20_ENV)
 695 struct fptr {
 696     void *ip;
 697     unsigned long gp;
 698 };
 699
 700 /*
 701  * syscall pairs/triplets to probe
 702  * This has to be empty, because anything that would work will
 703  * also match the main table, and that's no good.
 704  */
 705 static tryctl sct32_try[] = {
 706     { 0 }
 707 };
 708
 709 /* zapped syscalls for try_harder */
 710 static int sct32_zapped_syscalls[] = {
 711 #ifdef AFS_PPC64_LINUX20_ENV
 712     /* These should be sufficient */
 713     __NR_break, __NR_stty, __NR_gtty, __NR_ftime,
 714     __NR_prof, __NR_lock, __NR_mpx,
 715 #endif
 716 #ifdef AFS_SPARC64_LINUX20_ENV
 717     /* memory_ordering, getmsg, putmsg, unimplemented, modify_ldt */
 718     52, 151, 152, 164, 218,
 719 #endif
 720     0
 721 };
 722
 723 /* unique syscalls for try_harder */
 724 /* mmap2 and fstat64 are implemented only for 32-bit calls */
 725 static int sct32_unique_syscalls[] = {
 726 #ifdef AFS_PPC64_LINUX20_ENV
 727     /* _mmap2, _fstat64 */
 728     192, 197,
 729 #endif
 730 #ifdef AFS_SPARC64_LINUX24_ENV
 731     /*
 732      * On SPARC, we need some additional unique calls to make sure
 733      * we don't match the SunOS-compatibility table.
 734      */
 735     __NR_sgetmask, __NR_ssetmask,
 736 #endif
 737     __NR_exit, __NR_mount, __NR_read, __NR_write,
 738     __NR_open, __NR_close, __NR_unlink
 739 };
 740
 741 /* probe control structure */
 742 static probectl sct32_probe = {
 743     /* symbol name and description */
 744     "sys_call_table32",
 745     "32-bit system call table",
 746
 747     /* syscall number of first entry in table */
 748     0,
 749
 750     sys_call_table32,             /* weak symbol ref */
 751     0, 0,                         /* module parameter answers */
 752 #ifdef AFS_LINUX_sys_call_table32
 753     AFS_LINUX_sys_call_table32,   /* compiled-in answer, if any */
 754 #else
 755     0,
 756 #endif
 757
 758     sct32_try,                   /* array of combinations to try */
 759
 760     /* symbol in section to try scanning */
 761 #if defined(AFS_SPARC64_LINUX20_ENV)
 762     (unsigned long)&sys_close,
 763 #else
 764     (unsigned long)&init_mm,
 765 #endif
 766
 767     /* default base address for scan */
 768     /* base address bits to force to zero */
 769     /* default length for scan */
 770 #if   defined(AFS_SPARC64_LINUX20_ENV)
 771     (unsigned long)(&sys_close),
 772     0xfffff,
 773     0x10000,
 774 #elif defined(AFS_PPC64_LINUX26_ENV)
 775     (unsigned long)(&do_signal),
 776     0xfff,
 777     0x400,
 778 #else
 779     (unsigned long)&init_mm,
 780     0,
 781     16384,
 782 #endif
 783
 784     (unsigned long)scsi_command_size,
 785     (unsigned long)scsi_command_size - 0x10000,
 786     0x3ffff,
 787     0x40000,
 788
 789     /* number and list of unimplemented system calls */
 790     ((sizeof(sct32_zapped_syscalls)/sizeof(sct32_zapped_syscalls[0])) - 1),
 791     sct32_zapped_syscalls,
 792
 793     /* number and list of unique system calls */
 794     (sizeof(sct32_unique_syscalls)/sizeof(sct32_unique_syscalls[0])),
 795     sct32_unique_syscalls,
 796
 797     /* syscall number and pointer to verify match */
 798     __NR_close, &sys_close,
 799
 800     /* syscalls to ignore for debugging */
 801     {
 802 #if defined(AFS_SPARC64_LINUX20_ENV)
 803         227,
 804 #else
 805         137,
 806 #endif
 807         __NR_setgroups,
 808         -1,
 809         -1,
 810     }
 811 };
 812
 813 static probectl *probe_list[] = {
 814     &main_probe, &sct32_probe
 815 };
 816
 817
 818 /********** Probing Configuration: s390x sys_call_table_emu **********/
 819 /* We only actually need to do this on s390x_linux26 and later.
 820  * On earlier versions, the two tables were interleaved and so
 821  * have related base addresses.
 822  */
 823 #elif defined(AFS_S390X_LINUX26_ENV)
 824
 825 /* syscall pairs/triplets to probe */
 826 /* nothing worthwhile is exported, so this is empty */
 827 static tryctl emu_try[] = {
 828     { 0 }
 829 };
 830
 831 /* zapped syscalls for try_harder */
 832 static int emu_zapped_syscalls[] = {
 833     /* break, stty, gtty, ftime, prof, lock, mpx */
 834     17, 31, 32, 35, 44, 53, 56,
 835     0
 836 };
 837
 838 /* unique syscalls for try_harder */
 839 static int emu_unique_syscalls[] = {
 840     /* lchown16, fstat64 */
 841     16, 197,
 842     __NR_exit, __NR_mount, __NR_read, __NR_write,
 843     __NR_open, __NR_close, __NR_unlink
 844 };
 845
 846 /* probe control structure */
 847 static probectl emu_probe = {
 848     /* symbol name and description */
 849     "sys_call_table_emu",
 850     "32-bit system call table",
 851
 852     /* syscall number of first entry in table */
 853     0,
 854
 855     sys_call_table_emu,           /* weak symbol ref */
 856     0, 0,                         /* module parameter answers */
 857 #ifdef AFS_LINUX_sys_call_table_emu
 858     AFS_LINUX_sys_call_table_emu, /* compiled-in answer, if any */
 859 #else
 860     0,
 861 #endif
 862
 863     emu_try,                      /* array of combinations to try */
 864
 865     /* symbol in section to try scanning */
 866     (unsigned long)&sys_close,
 867
 868     /* default base address for scan */
 869     /* base address bits to force to zero */
 870     /* default length for scan */
 871     (unsigned long)&sys_close,
 872     0xfffff,
 873     0x20000,
 874
 875     (unsigned long)scsi_command_size,
 876     (unsigned long)scsi_command_size - 0x10000,
 877     0x3ffff,
 878     0x40000,
 879
 880     /* number and list of unimplemented system calls */
 881     ((sizeof(emu_zapped_syscalls)/sizeof(emu_zapped_syscalls[0])) - 1),
 882     emu_zapped_syscalls,
 883
 884     /* number and list of unique system calls */
 885     (sizeof(emu_unique_syscalls)/sizeof(emu_unique_syscalls[0])),
 886     emu_unique_syscalls,
 887
 888     /* syscall number and pointer to verify match */
 889     __NR_close, &sys_close,
 890
 891     /* syscalls to ignore for debugging */
 892     {
 893         137,
 894         __NR_setgroups,
 895         -1,
 896         -1,
 897     }
 898 };
 899
 900 static probectl *probe_list[] = {
 901     &main_probe, &emu_probe
 902 };
 903
 904
 905 /********** End of Probing Configuration **********/
 906
 907 #else /* no per-platform probe control, so use the default list */
 908 static probectl *probe_list[] = {
 909     &main_probe
 910 };
 911 #endif
 912
 913 #define N_PROBE_LIST (sizeof(probe_list) / sizeof(*probe_list))
 914 #define DEBUG_IN_RANGE(P,x) (!probe_debug_range ||                             \
 915   (P->debug_answer &&                                                          \
 916    (unsigned long)(x) >= (unsigned long)P->debug_answer &&                     \
 917    (unsigned long)(x) <  (unsigned long)P->debug_answer + probe_debug_range))
 918
 919
 920
 921 static int check_table(probectl *P, PROBETYPE *ptr)
 922 {
 923     PROBETYPE *x;
 924     int i, j;
 925
 926 #if defined(AFS_I386_LINUX26_ENV) || defined(AFS_AMD64_LINUX26_ENV)
 927     i = check_table_readable(P, ptr);
 928     if (i >= 0) return i;
 929 #endif
 930
 931     for (x = ptr, i = 0; i < _SS(NR_syscalls); i++, x++) {
 932 #ifdef OSI_PROBE_DEBUG
 933         if (probe_debug & 0x0040) {
 934             for (j = 0; j < 4; j++) {
 935                 if (_SS(P->debug_ignore_NR[j]) == _SX(i + P->offset)) break;
 936             }
 937             if (j < 4) continue;
 938         }
 939 #endif
 940         for (j = 0; j < 8; j++) {
 941             if (_SS(probe_ignore_syscalls[j]) == _SX(i) + P->offset) break;
 942         }
 943         if (j < 8) continue;
 944         if (*x <= ktxt_lower_bound) {
 945 #ifdef OSI_PROBE_DEBUG
 946             if ((probe_debug & 0x0008) && DEBUG_IN_RANGE(P,ptr))
 947                 printk("<7>check 0x%lx -> %d [0x%lx]\n",
 948                        (unsigned long)ptr, i, (unsigned long)*x);
 949 #endif
 950             return i;
 951         }
 952     }
 953 #ifdef OSI_PROBE_DEBUG
 954     if ((probe_debug & 0x0008) && DEBUG_IN_RANGE(P,ptr))
 955         printk("<7>check 0x%lx -> ok\n", (unsigned long)ptr);
 956 #endif
 957     return -1;
 958 }
 959
 960 static void *try(probectl *P, tryctl *T, PROBETYPE *aptr,
 961                  unsigned long datalen)
 962 {
 963 #ifdef OSI_PROBE_KALLSYMS
 964     char *mod_name, *sec_name, *sym_name;
 965     unsigned long mod_start, mod_end;
 966     unsigned long sec_start, sec_end;
 967     unsigned long sym_start, sym_end;
 968 #endif
 969     unsigned long offset, ip1, ip2, ip3;
 970     int ret;
 971     PROBETYPE *ptr;
 972
 973 #if defined(AFS_IA64_LINUX20_ENV) || defined(AFS_PPC64_LINUX20_ENV)
 974     ip1 = T->fn1 ? (unsigned long)((struct fptr *)T->fn1)->ip : 0;
 975     ip2 = T->fn2 ? (unsigned long)((struct fptr *)T->fn2)->ip : 0;
 976     ip3 = T->fn3 ? (unsigned long)((struct fptr *)T->fn3)->ip : 0;
 977 #else
 978     ip1 = (unsigned long)T->fn1;
 979     ip2 = (unsigned long)T->fn2;
 980     ip3 = (unsigned long)T->fn3;
 981 #endif
 982
 983 #ifdef OSI_PROBE_DEBUG
 984     if (probe_debug & 0x0001)
 985         printk("<7>osi_probe: %s                      %s (%d->0x%lx, %d->0x%lx, %d->0x%lx)\n",
 986                P->symbol, T->name, T->NR1, ip1, T->NR2, ip2, T->NR3, ip3);
 987 #endif
 988
 989     if (!ip1 || !ip2 || (T->NR3 >= 0 && !ip3))
 990         return 0;
 991
 992     for (offset = 0; offset < datalen; offset++, aptr++) {
 993 #if defined(AFS_PPC64_LINUX20_ENV)
 994         ptr = (PROBETYPE*)(*aptr);
 995         if ((unsigned long)ptr <= KERNELBASE) {
 996                 continue;
 997         }
 998 #else
 999         ptr = aptr;
1000 #endif
1001         if ((unsigned long)ptr < init_mm.start_code ||
1002 #if defined(AFS_AMD64_LINUX20_ENV)
1003                 (unsigned long)ptr > init_mm.brk)
1004 #else
1005                 (unsigned long)ptr > init_mm.end_data)
1006 #endif
1007         {
1008 /*           printk("address 0x%lx (from 0x%lx %d) is out of range in check_table. wtf?\n", (unsigned long)x, (unsigned long)ptr, i);*/
1009              continue;
1010         }
1011
1012         ret = check_table(P, ptr);
1013         if (ret >= 0) {
1014             /* return value is number of entries to skip */
1015             aptr    += ret;
1016             offset += ret;
1017             continue;
1018         }
1019
1020 #ifdef OSI_PROBE_DEBUG
1021         if ((probe_debug & 0x0002) && DEBUG_IN_RANGE(P,ptr))
1022             printk("<7>try 0x%lx\n", (unsigned long)ptr);
1023 #endif
1024         if (ptr[_SS(T->NR1 - P->offset)] != ip1)        continue;
1025         if (ptr[_SS(T->NR2 - P->offset)] != ip2)        continue;
1026         if (ip3 && ptr[_SS(T->NR3 - P->offset)] != ip3) continue;
1027
1028 #ifdef OSI_PROBE_DEBUG
1029         if (probe_debug & 0x0002)
1030             printk("<7>try found 0x%lx\n", (unsigned long)ptr);
1031 #endif
1032 #ifdef OSI_PROBE_KALLSYMS
1033         if (kallsyms_address_to_symbol) {
1034             ret = kallsyms_address_to_symbol((unsigned long)ptr,
1035                                              &mod_name, &mod_start, &mod_end,
1036                                              &sec_name, &sec_start, &sec_end,
1037                                              &sym_name, &sym_start, &sym_end);
1038             if (!ret || strcmp(sym_name, P->symbol)) continue;
1039         }
1040 #endif
1041         /* XXX should we make sure there is only one match? */
1042         return (void *)ptr;
1043     }
1044     return 0;
1045 }
1046
1047
1048 static int check_harder(probectl *P, PROBETYPE *p)
1049 {
1050     unsigned long ip1;
1051     int i, s;
1052
1053 #if defined(AFS_I386_LINUX26_ENV) || defined(AFS_AMD64_LINUX26_ENV)
1054     i = check_table_readable(P, p);
1055     if (i >= 0) return 0;
1056 #endif
1057
1058     /* Check zapped syscalls */
1059     for (i = 1; i < P->n_zapped_syscalls; i++) {
1060         if (p[_SS(P->zapped_syscalls[i])] != p[_SS(P->zapped_syscalls[0])]) {
1061 #ifdef OSI_PROBE_DEBUG
1062             if ((probe_debug & 0x0020) && DEBUG_IN_RANGE(P,p))
1063                 printk("<7>check_harder 0x%lx zapped failed i=%d\n", (unsigned long)p, i);
1064 #endif
1065             return 0;
1066         }
1067     }
1068
1069     /* Check unique syscalls */
1070     for (i = 0; i < P->n_unique_syscalls; i++) {
1071         for (s = 0; s < NR_syscalls; s++) {
1072             if (p[_SS(s)] == p[_SS(P->unique_syscalls[i])]
1073                 && s != P->unique_syscalls[i]) {
1074 #ifdef OSI_PROBE_DEBUG
1075                 if ((probe_debug & 0x0010) && DEBUG_IN_RANGE(P,p))
1076                     printk("<7>check_harder 0x%lx unique failed i=%d s=%d\n", (unsigned long)p, i, s);
1077 #endif
1078                 return 0;
1079             }
1080         }
1081     }
1082
1083 #if defined(AFS_IA64_LINUX20_ENV) || defined(AFS_PPC64_LINUX20_ENV)
1084     ip1 = P->verify_fn ? (unsigned long)((struct fptr *)(P->verify_fn))->ip : 0;
1085 #else
1086     ip1 = (unsigned long)(P->verify_fn);
1087 #endif
1088
1089     if (ip1 && p[_SS(P->verifyNR - P->offset)] != ip1) {
1090 #ifdef OSI_PROBE_DEBUG
1091         if ((probe_debug & 0x0010) && DEBUG_IN_RANGE(P,p))
1092             printk("<7>check_harder 0x%lx verify failed\n", (unsigned long)p);
1093 #endif
1094         return 0;
1095     }
1096
1097 #ifdef OSI_PROBE_DEBUG
1098     if ((probe_debug & 0x0010) && DEBUG_IN_RANGE(P,p))
1099         printk("<7>check_harder 0x%lx success!\n", (unsigned long)p);
1100 #endif
1101     return 1;
1102 }
1103
1104 static void *try_harder(probectl *P, PROBETYPE *ptr, unsigned long datalen)
1105 {
1106 #ifdef OSI_PROBE_KALLSYMS
1107     char *mod_name, *sec_name, *sym_name;
1108     unsigned long mod_start, mod_end;
1109     unsigned long sec_start, sec_end;
1110     unsigned long sym_start, sym_end;
1111 #endif
1112     unsigned long offset;
1113     void *match = 0;
1114     int ret;
1115
1116 #ifdef OSI_PROBE_DEBUG
1117     if (probe_debug & 0x0001)
1118         printk("<7>osi_probe: %s                      try_harder\n", P->symbol);
1119 #endif
1120     for (offset = 0; offset < datalen; offset++, ptr++) {
1121          if ((unsigned long)ptr < init_mm.start_code ||
1122 #if defined(AFS_AMD64_LINUX20_ENV)
1123                 (unsigned long)ptr > init_mm.brk)
1124 #else
1125                 (unsigned long)ptr > init_mm.end_data)
1126 #endif
1127         {
1128 /*           printk("address 0x%lx (from 0x%lx %d) is out of range in check_table. wtf?\n", (unsigned long)x, (unsigned long)ptr, i);*/
1129              continue;
1130         }
1131         ret = check_table(P, ptr);
1132         if (ret >= 0) {
1133             /* return value is number of entries to skip */
1134             ptr    += ret;
1135             offset += ret;
1136             continue;
1137         }
1138
1139 #ifdef OSI_PROBE_DEBUG
1140         if ((probe_debug & 0x0004) && DEBUG_IN_RANGE(P,ptr))
1141             printk("<7>try_harder 0x%lx\n", (unsigned long)ptr);
1142 #endif
1143         if (!check_harder(P, ptr))
1144             continue;
1145
1146 #ifdef OSI_PROBE_DEBUG
1147         if (probe_debug & 0x0004)
1148             printk("<7>try_harder found 0x%lx\n", (unsigned long)ptr);
1149 #endif
1150
1151 #ifdef OSI_PROBE_KALLSYMS
1152         if (kallsyms_address_to_symbol) {
1153             ret = kallsyms_address_to_symbol((unsigned long)ptr,
1154                                              &mod_name, &mod_start, &mod_end,
1155                                              &sec_name, &sec_start, &sec_end,
1156                                              &sym_name, &sym_start, &sym_end);
1157             if (!ret || strcmp(sym_name, P->symbol)) continue;
1158         }
1159 #endif
1160
1161         if (match) {
1162 #ifdef OSI_PROBE_DEBUG
1163             if (probe_debug & 0x0005)
1164                 printk("<7>%s: try_harder found multiple matches!\n", P->symbol);
1165 #endif
1166             return 0;
1167         }
1168
1169         match = (void *)ptr;
1170         if (!probe_carefully)
1171             break;
1172     }
1173     return match;
1174 }
1175
1176
1177 #ifdef OSI_PROBE_DEBUG
1178 #define check_result(x,m) do {                                                             \
1179     if (probe_debug & 0x0001) {                                                              \
1180         printk("<7>osi_probe: %s = 0x%016lx %s\n", P->symbol, (unsigned long)(x), (m)); \
1181     }                                                                                      \
1182     if ((x) && ((int)(x)) != -ENOENT) {                                                    \
1183         *method = (m);                                                                     \
1184         final_answer = (void *)(x);                                                        \
1185     }                                                                                      \
1186 } while (0)
1187 #else
1188 #define check_result(x,m) do {  \
1189     if ((x) && ((int)(x)) != -ENOENT) { \
1190         *method = (m);          \
1191         return (void *)(x);     \
1192     }                           \
1193 } while (0)
1194 #endif
1195 static void *scan_for_syscall_table(probectl *P, PROBETYPE *B, unsigned long L)
1196 {
1197     tryctl *T;
1198     void *answer;
1199 #if defined(AFS_S390_LINUX20_ENV) || defined(AFS_S390X_LINUX20_ENV)
1200     void *answer2;
1201 #endif
1202 #ifdef OSI_PROBE_DEBUG
1203     void *final_answer = 0;
1204 #endif
1205 #ifdef OSI_PROBE_DEBUG
1206     if (probe_debug & 0x0007)
1207         printk("<7>osi_probe: %s                      base=0x%lx, len=0x%lx\n",
1208                P->symbol, (unsigned long)B, L);
1209     if (probe_debug & 0x0009) {
1210         printk("<7>osi_probe: %s                      ktxt_lower_bound=0x%lx\n",
1211                P->symbol, ktxt_lower_bound);
1212         printk("<7>osi_probe: %s                      NR_syscalls=%d\n",
1213                P->symbol, NR_syscalls);
1214     }
1215 #endif
1216
1217     for (T = P->trylist; T->name; T++) {
1218         answer = try(P, T, B, L);
1219 #if defined(AFS_S390_LINUX20_ENV) || defined(AFS_S390X_LINUX20_ENV)
1220         answer2 = try(P, T, (PROBETYPE *)(2 + (void *)B), L);
1221 #ifdef OSI_PROBE_DEBUG
1222         if (probe_debug & 0x0003) {
1223             printk("<7>osi_probe: %s = 0x%016lx %s (even)\n",
1224                    P->symbol, (unsigned long)(answer), T->name);
1225             printk("<7>osi_probe: %s = 0x%016lx %s (odd)\n",
1226                    P->symbol, (unsigned long)(answer2), T->name);
1227         }
1228 #endif
1229         if (answer && answer2) answer = 0;
1230         else if (answer2) answer = answer2;
1231 #endif
1232         if (answer)
1233             return answer;
1234     }
1235
1236     /* XXX more checks here */
1237
1238     answer = try_harder(P, B, L);
1239 #if defined(AFS_S390_LINUX20_ENV) || defined(AFS_S390X_LINUX20_ENV)
1240     answer2 = try_harder(P, (PROBETYPE *)(2 + (void *)B), L);
1241 #ifdef OSI_PROBE_DEBUG
1242     if (probe_debug & 0x0005) {
1243         printk("<7>osi_probe: %s = 0x%016lx pattern scan (even)\n",
1244                P->symbol, (unsigned long)(answer));
1245         printk("<7>osi_probe: %s = 0x%016lx pattern scan (odd)\n",
1246                P->symbol, (unsigned long)(answer2));
1247     }
1248 #endif
1249     if (answer && answer2) answer = 0;
1250     else if (answer2) answer = answer2;
1251 #endif
1252     return answer;
1253 }
1254
1255 static void *do_find_syscall_table(probectl *P, char **method)
1256 {
1257 #ifdef OSI_PROBE_KALLSYMS
1258     char *mod_name, *sec_name, *sym_name;
1259     unsigned long mod_start, mod_end;
1260     unsigned long sec_start, sec_end;
1261     unsigned long sym_start, sym_end;
1262     unsigned long token;
1263     int ret;
1264 #endif
1265     PROBETYPE *B;
1266     unsigned long L;
1267     void *answer;
1268 #ifdef OSI_PROBE_DEBUG
1269     void *final_answer = 0;
1270 #endif
1271
1272     *method = "not found";
1273
1274     /* if it's exported, there's nothing to do */
1275     check_result(P->weak_answer, "exported");
1276
1277     /* ask the kernel to do the name lookup, if it's willing */
1278 #ifdef OSI_PROBE_KALLSYMS
1279     if (kallsyms_symbol_to_address) {
1280         token = 0;
1281         sym_start = 0;
1282         do {
1283             ret = kallsyms_symbol_to_address(P->symbol, &token,
1284                                              &mod_name, &mod_start, &mod_end,
1285                                              &sec_name, &sec_start, &sec_end,
1286                                              &sym_name, &sym_start, &sym_end);
1287             if (ret && !strcmp(mod_name, "kernel") && sym_start)
1288                 break;
1289             sym_start = 0;
1290         } while (ret);
1291         check_result(sym_start, "kallsyms_symbol_to_address");
1292     }
1293 #endif
1294
1295     /* Maybe a little birdie told us */
1296     check_result(P->parm_answer,  "module parameter");
1297     check_result(P->given_answer, "compiled-in");
1298
1299     /* OK, so we have to scan. */
1300     B = (PROBETYPE *)((P->try_base) & ~(P->try_base_mask));
1301     L = P->try_length;
1302     /* Now, see if the kernel will tell us something better than the default */
1303 #ifdef OSI_PROBE_KALLSYMS
1304     if (kallsyms_address_to_symbol) {
1305         ret = kallsyms_address_to_symbol(P->try_sect_sym,
1306                                          &mod_name, &mod_start, &mod_end,
1307                                          &sec_name, &sec_start, &sec_end,
1308                                          &sym_name, &sym_start, &sym_end);
1309         if (ret) {
1310             B = (PROBETYPE *)sec_start;
1311             L = (sec_end - sec_start) / sizeof(unsigned long);
1312         }
1313     }
1314 #endif
1315
1316     answer = scan_for_syscall_table(P, B, L);
1317     check_result(answer, "pattern scan");
1318     B = (PROBETYPE *)((P->alt_try_base) & ~(P->alt_try_base_mask));
1319     L = P->alt_try_length;
1320     /* Now, see if the kernel will tell us something better than the default */
1321 #ifdef OSI_PROBE_KALLSYMS
1322     if (kallsyms_address_to_symbol && P->alt_try_sect_sym) {
1323         ret = kallsyms_address_to_symbol(P->alt_try_sect_sym,
1324                                          &mod_name, &mod_start, &mod_end,
1325                                          &sec_name, &sec_start, &sec_end,
1326                                          &sym_name, &sym_start, &sym_end);
1327         if (ret) {
1328             B = (PROBETYPE *)sec_start;
1329             L = (sec_end - sec_start) / sizeof(unsigned long);
1330         }
1331     }
1332 #endif
1333     if (B && L) {
1334         answer = scan_for_syscall_table(P, B, L);
1335         check_result(answer, "pattern scan");
1336     }
1337 #ifdef OSI_PROBE_DEBUG
1338     return final_answer;
1339 #else
1340     return 0;
1341 #endif
1342 }
1343
1344 #if defined(AFS_I386_LINUX26_ENV) || defined(AFS_AMD64_LINUX26_ENV)
1345 static int check_access(unsigned long address, int mode)
1346 {
1347     pgd_t *pgd = pgd_offset_k(address);
1348 #ifdef PUD_SIZE
1349     pud_t *pud;
1350 #endif
1351     pmd_t *pmd;
1352     pte_t *pte;
1353
1354     if (pgd_none(*pgd))
1355         return 0;
1356 #ifdef PUD_SIZE
1357     pud = pud_offset(pgd, address);
1358     if (pud_none(*pud))
1359         return 0;
1360     pmd = pmd_offset(pud, address);
1361 #else
1362     pmd = pmd_offset(pgd, address);
1363 #endif
1364     if (pmd_none(*pmd))
1365         return 0;
1366     if (pmd_large(*pmd))
1367         pte = (pte_t *)pmd;
1368     else
1369         pte = pte_offset_kernel(pmd, address);
1370     if (pte_none(*pte) || !pte_present(*pte))
1371         return 0;
1372     if (mode && !pte_write(*pte))
1373         return 0;
1374     return 1;
1375 }
1376
1377 static int check_table_readable(probectl *P, PROBETYPE *ptr)
1378 {
1379     PROBETYPE *next_page;
1380     int i = 0, delta;
1381
1382     while (i < _SS(NR_syscalls)) {
1383         next_page = (PROBETYPE *)PAGE_ALIGN((unsigned long)(ptr+1));
1384         delta = next_page - ptr;
1385         if (!check_access((unsigned long)ptr, 0)) {
1386 #ifdef OSI_PROBE_DEBUG
1387             if (probe_debug & 0x0080)
1388                 printk("<7>osi_probe: %s                      0x%016lx not readable; delta=0x%lx\n",
1389                        P->symbol, (unsigned long)ptr, delta);
1390 #endif
1391             return delta - 1;
1392         }
1393         ptr += delta;
1394         i += delta;
1395     }
1396     return -1;
1397 }
1398 #endif
1399
1400 void *osi_find_syscall_table(int which)
1401 {
1402     probectl *P;
1403     void *answer;
1404     char *method;
1405
1406     if (which < 0 || which >= N_PROBE_LIST) {
1407         printk("error - afs_find_syscall_table called with invalid index!\n");
1408         return 0;
1409     }
1410     P = probe_list[which];
1411     if (which < 4) {
1412         P->parm_answer = (void *)sys_call_table_addr[which];
1413 #ifdef OSI_PROBE_DEBUG
1414         P->debug_answer = (void *)probe_debug_addr[which];
1415 #endif
1416     }
1417     answer = do_find_syscall_table(P, &method);
1418     if (!answer) {
1419         printk("Warning: failed to find address of %s\n", P->desc);
1420         printk("System call hooks will not be installed; proceeding anyway\n");
1421         return 0;
1422     }
1423     printk("Found %s at 0x%lx (%s)\n", P->desc, (unsigned long)answer, method);
1424 #if defined(AFS_I386_LINUX26_ENV) || defined(AFS_AMD64_LINUX26_ENV)
1425     if (!check_access((unsigned long)answer, 1)) {
1426         printk("Address 0x%lx is not writable.\n", (unsigned long)answer);
1427         printk("System call hooks will not be installed; proceeding anyway\n");
1428         return 0;
1429     }
1430 #endif
1431     return answer;
1432 }
1433
1434
1435 #ifdef OSI_PROBE_STANDALONE
1436 int __init osi_probe_init(void)
1437 {
1438     int i;
1439
1440     if (!probe_debug_tag) probe_debug_tag = jiffies;
1441     printk("*** osi_probe %ld debug = 0x%04x ***\n",
1442            probe_debug_tag, probe_debug);
1443     for (i = 0; i < N_PROBE_LIST; i++)
1444         (void)osi_find_syscall_table(i);
1445     return 0;
1446 }
1447
1448 void osi_probe_exit(void) { }
1449
1450 module_init(osi_probe_init);
1451 module_exit(osi_probe_exit);
1452 #endif
1453
1454 #else
1455 void *osi_find_syscall_table(int which)
1456 {
1457     return 0;
1458 }
1459 #endif /* EXPORTED_INIT_MM */