kernel/trace/trace_probe.c

   1 /*
   2  * Common code for probe-based Dynamic events.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  16  *
  17  * This code was copied from kernel/trace/trace_kprobe.c written by
  18  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
  19  *
  20  * Updates to make this generic:
  21  * Copyright (C) IBM Corporation, 2010-2011
  22  * Author:     Srikar Dronamraju
  23  */
  24
  25 #include "trace_probe.h"
  26
  27 const char *reserved_field_names[] = {
  28         "common_type",
  29         "common_flags",
  30         "common_preempt_count",
  31         "common_pid",
  32         "common_tgid",
  33         FIELD_STRING_IP,
  34         FIELD_STRING_RETIP,
  35         FIELD_STRING_FUNC,
  36 };
  37
  38 /* Printing function type */
  39 #define PRINT_TYPE_FUNC_NAME(type)      print_type_##type
  40 #define PRINT_TYPE_FMT_NAME(type)       print_type_format_##type
  41
  42 /* Printing  in basic type function template */
  43 #define DEFINE_BASIC_PRINT_TYPE_FUNC(type, fmt, cast)                   \
  44 static __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,    \
  45                                                 const char *name,       \
  46                                                 void *data, void *ent)\
  47 {                                                                       \
  48         return trace_seq_printf(s, " %s=" fmt, name, (cast)*(type *)data);\
  49 }                                                                       \
  50 static const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
  51
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, "%x", unsigned int)
  53 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "%x", unsigned int)
  54 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "%lx", unsigned long)
  55 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "%llx", unsigned long long)
  56 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, "%d", int)
  57 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d", int)
  58 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%ld", long)
  59 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%lld", long long)
  60
  61 static inline void *get_rloc_data(u32 *dl)
  62 {
  63         return (u8 *)dl + get_rloc_offs(*dl);
  64 }
  65
  66 /* For data_loc conversion */
  67 static inline void *get_loc_data(u32 *dl, void *ent)
  68 {
  69         return (u8 *)ent + get_rloc_offs(*dl);
  70 }
  71
  72 /* For defining macros, define string/string_size types */
  73 typedef u32 string;
  74 typedef u32 string_size;
  75
  76 /* Print type function for string type */
  77 static __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
  78                                                   const char *name,
  79                                                   void *data, void *ent)
  80 {
  81         int len = *(u32 *)data >> 16;
  82
  83         if (!len)
  84                 return trace_seq_printf(s, " %s=(fault)", name);
  85         else
  86                 return trace_seq_printf(s, " %s=\"%s\"", name,
  87                                         (const char *)get_loc_data(data, ent));
  88 }
  89
  90 static const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  91
  92 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
  93 /*
  94  * Define macro for basic types - we don't need to define s* types, because
  95  * we have to care only about bitwidth at recording time.
  96  */
  97 #define DEFINE_BASIC_FETCH_FUNCS(method) \
  98 DEFINE_FETCH_##method(u8)               \
  99 DEFINE_FETCH_##method(u16)              \
 100 DEFINE_FETCH_##method(u32)              \
 101 DEFINE_FETCH_##method(u64)
 102
 103 #define CHECK_FETCH_FUNCS(method, fn)                   \
 104         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
 105           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
 106           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
 107           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
 108           (FETCH_FUNC_NAME(method, string) == fn) ||    \
 109           (FETCH_FUNC_NAME(method, string_size) == fn)) \
 110          && (fn != NULL))
 111
 112 /* Data fetch function templates */
 113 #define DEFINE_FETCH_reg(type)                                          \
 114 static __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,  \
 115                                         void *offset, void *dest)       \
 116 {                                                                       \
 117         *(type *)dest = (type)regs_get_register(regs,                   \
 118                                 (unsigned int)((unsigned long)offset)); \
 119 }
 120 DEFINE_BASIC_FETCH_FUNCS(reg)
 121 /* No string on the register */
 122 #define fetch_reg_string        NULL
 123 #define fetch_reg_string_size   NULL
 124
 125 #define DEFINE_FETCH_stack(type)                                        \
 126 static __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,\
 127                                           void *offset, void *dest)     \
 128 {                                                                       \
 129         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 130                                 (unsigned int)((unsigned long)offset)); \
 131 }
 132 DEFINE_BASIC_FETCH_FUNCS(stack)
 133 /* No string on the stack entry */
 134 #define fetch_stack_string      NULL
 135 #define fetch_stack_string_size NULL
 136
 137 #define DEFINE_FETCH_retval(type)                                       \
 138 static __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,\
 139                                           void *dummy, void *dest)      \
 140 {                                                                       \
 141         *(type *)dest = (type)regs_return_value(regs);                  \
 142 }
 143 DEFINE_BASIC_FETCH_FUNCS(retval)
 144 /* No string on the retval */
 145 #define fetch_retval_string             NULL
 146 #define fetch_retval_string_size        NULL
 147
 148 #define DEFINE_FETCH_memory(type)                                       \
 149 static __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,\
 150                                           void *addr, void *dest)       \
 151 {                                                                       \
 152         type retval;                                                    \
 153         if (probe_kernel_address(addr, retval))                         \
 154                 *(type *)dest = 0;                                      \
 155         else                                                            \
 156                 *(type *)dest = retval;                                 \
 157 }
 158 DEFINE_BASIC_FETCH_FUNCS(memory)
 159 /*
 160  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 161  * length and relative data location.
 162  */
 163 static __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 164                                                       void *addr, void *dest)
 165 {
 166         long ret;
 167         int maxlen = get_rloc_len(*(u32 *)dest);
 168         u8 *dst = get_rloc_data(dest);
 169         u8 *src = addr;
 170         mm_segment_t old_fs = get_fs();
 171
 172         if (!maxlen)
 173                 return;
 174
 175         /*
 176          * Try to get string again, since the string can be changed while
 177          * probing.
 178          */
 179         set_fs(KERNEL_DS);
 180         pagefault_disable();
 181
 182         do
 183                 ret = __copy_from_user_inatomic(dst++, src++, 1);
 184         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
 185
 186         dst[-1] = '\0';
 187         pagefault_enable();
 188         set_fs(old_fs);
 189
 190         if (ret < 0) {  /* Failed to fetch string */
 191                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 192                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 193         } else {
 194                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
 195                                               get_rloc_offs(*(u32 *)dest));
 196         }
 197 }
 198
 199 /* Return the length of string -- including null terminal byte */
 200 static __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 201                                                         void *addr, void *dest)
 202 {
 203         mm_segment_t old_fs;
 204         int ret, len = 0;
 205         u8 c;
 206
 207         old_fs = get_fs();
 208         set_fs(KERNEL_DS);
 209         pagefault_disable();
 210
 211         do {
 212                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 213                 len++;
 214         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 215
 216         pagefault_enable();
 217         set_fs(old_fs);
 218
 219         if (ret < 0)    /* Failed to check the length */
 220                 *(u32 *)dest = 0;
 221         else
 222                 *(u32 *)dest = len;
 223 }
 224
 225 /* Memory fetching by symbol */
 226 struct symbol_cache {
 227         char            *symbol;
 228         long            offset;
 229         unsigned long   addr;
 230 };
 231
 232 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 233 {
 234         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 235
 236         if (sc->addr)
 237                 sc->addr += sc->offset;
 238
 239         return sc->addr;
 240 }
 241
 242 static void free_symbol_cache(struct symbol_cache *sc)
 243 {
 244         kfree(sc->symbol);
 245         kfree(sc);
 246 }
 247
 248 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 249 {
 250         struct symbol_cache *sc;
 251
 252         if (!sym || strlen(sym) == 0)
 253                 return NULL;
 254
 255         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 256         if (!sc)
 257                 return NULL;
 258
 259         sc->symbol = kstrdup(sym, GFP_KERNEL);
 260         if (!sc->symbol) {
 261                 kfree(sc);
 262                 return NULL;
 263         }
 264         sc->offset = offset;
 265         update_symbol_cache(sc);
 266
 267         return sc;
 268 }
 269
 270 #define DEFINE_FETCH_symbol(type)                                       \
 271 static __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,\
 272                                           void *data, void *dest)       \
 273 {                                                                       \
 274         struct symbol_cache *sc = data;                                 \
 275         if (sc->addr)                                                   \
 276                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 277         else                                                            \
 278                 *(type *)dest = 0;                                      \
 279 }
 280 DEFINE_BASIC_FETCH_FUNCS(symbol)
 281 DEFINE_FETCH_symbol(string)
 282 DEFINE_FETCH_symbol(string_size)
 283
 284 /* Dereference memory access function */
 285 struct deref_fetch_param {
 286         struct fetch_param      orig;
 287         long                    offset;
 288 };
 289
 290 #define DEFINE_FETCH_deref(type)                                        \
 291 static __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,\
 292                                             void *data, void *dest)     \
 293 {                                                                       \
 294         struct deref_fetch_param *dprm = data;                          \
 295         unsigned long addr;                                             \
 296         call_fetch(&dprm->orig, regs, &addr);                           \
 297         if (addr) {                                                     \
 298                 addr += dprm->offset;                                   \
 299                 fetch_memory_##type(regs, (void *)addr, dest);          \
 300         } else                                                          \
 301                 *(type *)dest = 0;                                      \
 302 }
 303 DEFINE_BASIC_FETCH_FUNCS(deref)
 304 DEFINE_FETCH_deref(string)
 305 DEFINE_FETCH_deref(string_size)
 306
 307 static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)
 308 {
 309         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 310                 update_deref_fetch_param(data->orig.data);
 311         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 312                 update_symbol_cache(data->orig.data);
 313 }
 314
 315 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
 316 {
 317         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 318                 free_deref_fetch_param(data->orig.data);
 319         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 320                 free_symbol_cache(data->orig.data);
 321         kfree(data);
 322 }
 323
 324 /* Bitfield fetch function */
 325 struct bitfield_fetch_param {
 326         struct fetch_param      orig;
 327         unsigned char           hi_shift;
 328         unsigned char           low_shift;
 329 };
 330
 331 #define DEFINE_FETCH_bitfield(type)                                     \
 332 static __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,\
 333                                             void *data, void *dest)     \
 334 {                                                                       \
 335         struct bitfield_fetch_param *bprm = data;                       \
 336         type buf = 0;                                                   \
 337         call_fetch(&bprm->orig, regs, &buf);                            \
 338         if (buf) {                                                      \
 339                 buf <<= bprm->hi_shift;                                 \
 340                 buf >>= bprm->low_shift;                                \
 341         }                                                               \
 342         *(type *)dest = buf;                                            \
 343 }
 344
 345 DEFINE_BASIC_FETCH_FUNCS(bitfield)
 346 #define fetch_bitfield_string           NULL
 347 #define fetch_bitfield_string_size      NULL
 348
 349 static __kprobes void
 350 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
 351 {
 352         /*
 353          * Don't check the bitfield itself, because this must be the
 354          * last fetch function.
 355          */
 356         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 357                 update_deref_fetch_param(data->orig.data);
 358         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 359                 update_symbol_cache(data->orig.data);
 360 }
 361
 362 static __kprobes void
 363 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
 364 {
 365         /*
 366          * Don't check the bitfield itself, because this must be the
 367          * last fetch function.
 368          */
 369         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 370                 free_deref_fetch_param(data->orig.data);
 371         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 372                 free_symbol_cache(data->orig.data);
 373
 374         kfree(data);
 375 }
 376
 377 /* Default (unsigned long) fetch type */
 378 #define __DEFAULT_FETCH_TYPE(t) u##t
 379 #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t)
 380 #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG)
 381 #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)
 382
 383 #define ASSIGN_FETCH_FUNC(method, type) \
 384         [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type)
 385
 386 #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \
 387         {.name = _name,                         \
 388          .size = _size,                                 \
 389          .is_signed = sign,                             \
 390          .print = PRINT_TYPE_FUNC_NAME(ptype),          \
 391          .fmt = PRINT_TYPE_FMT_NAME(ptype),             \
 392          .fmttype = _fmttype,                           \
 393          .fetch = {                                     \
 394 ASSIGN_FETCH_FUNC(reg, ftype),                          \
 395 ASSIGN_FETCH_FUNC(stack, ftype),                        \
 396 ASSIGN_FETCH_FUNC(retval, ftype),                       \
 397 ASSIGN_FETCH_FUNC(memory, ftype),                       \
 398 ASSIGN_FETCH_FUNC(symbol, ftype),                       \
 399 ASSIGN_FETCH_FUNC(deref, ftype),                        \
 400 ASSIGN_FETCH_FUNC(bitfield, ftype),                     \
 401           }                                             \
 402         }
 403
 404 #define ASSIGN_FETCH_TYPE(ptype, ftype, sign)                   \
 405         __ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, #ptype)
 406
 407 #define FETCH_TYPE_STRING       0
 408 #define FETCH_TYPE_STRSIZE      1
 409
 410 /* Fetch type information table */
 411 static const struct fetch_type fetch_type_table[] = {
 412         /* Special types */
 413         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 414                                         sizeof(u32), 1, "__data_loc char[]"),
 415         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 416                                         string_size, sizeof(u32), 0, "u32"),
 417         /* Basic types */
 418         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 419         ASSIGN_FETCH_TYPE(u16, u16, 0),
 420         ASSIGN_FETCH_TYPE(u32, u32, 0),
 421         ASSIGN_FETCH_TYPE(u64, u64, 0),
 422         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 423         ASSIGN_FETCH_TYPE(s16, u16, 1),
 424         ASSIGN_FETCH_TYPE(s32, u32, 1),
 425         ASSIGN_FETCH_TYPE(s64, u64, 1),
 426 };
 427
 428 static const struct fetch_type *find_fetch_type(const char *type)
 429 {
 430         int i;
 431
 432         if (!type)
 433                 type = DEFAULT_FETCH_TYPE_STR;
 434
 435         /* Special case: bitfield */
 436         if (*type == 'b') {
 437                 unsigned long bs;
 438
 439                 type = strchr(type, '/');
 440                 if (!type)
 441                         goto fail;
 442
 443                 type++;
 444                 if (kstrtoul(type, 0, &bs))
 445                         goto fail;
 446
 447                 switch (bs) {
 448                 case 8:
 449                         return find_fetch_type("u8");
 450                 case 16:
 451                         return find_fetch_type("u16");
 452                 case 32:
 453                         return find_fetch_type("u32");
 454                 case 64:
 455                         return find_fetch_type("u64");
 456                 default:
 457                         goto fail;
 458                 }
 459         }
 460
 461         for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
 462                 if (strcmp(type, fetch_type_table[i].name) == 0)
 463                         return &fetch_type_table[i];
 464
 465 fail:
 466         return NULL;
 467 }
 468
 469 /* Special function : only accept unsigned long */
 470 static __kprobes void fetch_stack_address(struct pt_regs *regs,
 471                                         void *dummy, void *dest)
 472 {
 473         *(unsigned long *)dest = kernel_stack_pointer(regs);
 474 }
 475
 476 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
 477                                         fetch_func_t orig_fn)
 478 {
 479         int i;
 480
 481         if (type != &fetch_type_table[FETCH_TYPE_STRING])
 482                 return NULL;    /* Only string type needs size function */
 483
 484         for (i = 0; i < FETCH_MTD_END; i++)
 485                 if (type->fetch[i] == orig_fn)
 486                         return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
 487
 488         WARN_ON(1);     /* This should not happen */
 489
 490         return NULL;
 491 }
 492
 493 /* Split symbol and offset. */
 494 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
 495 {
 496         char *tmp;
 497         int ret;
 498
 499         if (!offset)
 500                 return -EINVAL;
 501
 502         tmp = strchr(symbol, '+');
 503         if (tmp) {
 504                 /* skip sign because kstrtoul doesn't accept '+' */
 505                 ret = kstrtoul(tmp + 1, 0, offset);
 506                 if (ret)
 507                         return ret;
 508
 509                 *tmp = '\0';
 510         } else
 511                 *offset = 0;
 512
 513         return 0;
 514 }
 515
 516 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 517
 518 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 519                             struct fetch_param *f, bool is_return)
 520 {
 521         int ret = 0;
 522         unsigned long param;
 523
 524         if (strcmp(arg, "retval") == 0) {
 525                 if (is_return)
 526                         f->fn = t->fetch[FETCH_MTD_retval];
 527                 else
 528                         ret = -EINVAL;
 529         } else if (strncmp(arg, "stack", 5) == 0) {
 530                 if (arg[5] == '\0') {
 531                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 532                                 f->fn = fetch_stack_address;
 533                         else
 534                                 ret = -EINVAL;
 535                 } else if (isdigit(arg[5])) {
 536                         ret = kstrtoul(arg + 5, 10, &param);
 537                         if (ret || param > PARAM_MAX_STACK)
 538                                 ret = -EINVAL;
 539                         else {
 540                                 f->fn = t->fetch[FETCH_MTD_stack];
 541                                 f->data = (void *)param;
 542                         }
 543                 } else
 544                         ret = -EINVAL;
 545         } else
 546                 ret = -EINVAL;
 547
 548         return ret;
 549 }
 550
 551 /* Recursive argument parser */
 552 static int parse_probe_arg(char *arg, const struct fetch_type *t,
 553                      struct fetch_param *f, bool is_return, bool is_kprobe)
 554 {
 555         unsigned long param;
 556         long offset;
 557         char *tmp;
 558         int ret;
 559
 560         ret = 0;
 561
 562         /* Until uprobe_events supports only reg arguments */
 563         if (!is_kprobe && arg[0] != '%')
 564                 return -EINVAL;
 565
 566         switch (arg[0]) {
 567         case '$':
 568                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 569                 break;
 570
 571         case '%':       /* named register */
 572                 ret = regs_query_register_offset(arg + 1);
 573                 if (ret >= 0) {
 574                         f->fn = t->fetch[FETCH_MTD_reg];
 575                         f->data = (void *)(unsigned long)ret;
 576                         ret = 0;
 577                 }
 578                 break;
 579
 580         case '@':       /* memory or symbol */
 581                 if (isdigit(arg[1])) {
 582                         ret = kstrtoul(arg + 1, 0, &param);
 583                         if (ret)
 584                                 break;
 585
 586                         f->fn = t->fetch[FETCH_MTD_memory];
 587                         f->data = (void *)param;
 588                 } else {
 589                         ret = traceprobe_split_symbol_offset(arg + 1, &offset);
 590                         if (ret)
 591                                 break;
 592
 593                         f->data = alloc_symbol_cache(arg + 1, offset);
 594                         if (f->data)
 595                                 f->fn = t->fetch[FETCH_MTD_symbol];
 596                 }
 597                 break;
 598
 599         case '+':       /* deref memory */
 600                 arg++;  /* Skip '+', because kstrtol() rejects it. */
 601         case '-':
 602                 tmp = strchr(arg, '(');
 603                 if (!tmp)
 604                         break;
 605
 606                 *tmp = '\0';
 607                 ret = kstrtol(arg, 0, &offset);
 608
 609                 if (ret)
 610                         break;
 611
 612                 arg = tmp + 1;
 613                 tmp = strrchr(arg, ')');
 614
 615                 if (tmp) {
 616                         struct deref_fetch_param        *dprm;
 617                         const struct fetch_type         *t2;
 618
 619                         t2 = find_fetch_type(NULL);
 620                         *tmp = '\0';
 621                         dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
 622
 623                         if (!dprm)
 624                                 return -ENOMEM;
 625
 626                         dprm->offset = offset;
 627                         ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
 628                                                         is_kprobe);
 629                         if (ret)
 630                                 kfree(dprm);
 631                         else {
 632                                 f->fn = t->fetch[FETCH_MTD_deref];
 633                                 f->data = (void *)dprm;
 634                         }
 635                 }
 636                 break;
 637         }
 638         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
 639                 pr_info("%s type has no corresponding fetch method.\n", t->name);
 640                 ret = -EINVAL;
 641         }
 642
 643         return ret;
 644 }
 645
 646 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 647
 648 /* Bitfield type needs to be parsed into a fetch function */
 649 static int __parse_bitfield_probe_arg(const char *bf,
 650                                       const struct fetch_type *t,
 651                                       struct fetch_param *f)
 652 {
 653         struct bitfield_fetch_param *bprm;
 654         unsigned long bw, bo;
 655         char *tail;
 656
 657         if (*bf != 'b')
 658                 return 0;
 659
 660         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
 661         if (!bprm)
 662                 return -ENOMEM;
 663
 664         bprm->orig = *f;
 665         f->fn = t->fetch[FETCH_MTD_bitfield];
 666         f->data = (void *)bprm;
 667         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 668
 669         if (bw == 0 || *tail != '@')
 670                 return -EINVAL;
 671
 672         bf = tail + 1;
 673         bo = simple_strtoul(bf, &tail, 0);
 674
 675         if (tail == bf || *tail != '/')
 676                 return -EINVAL;
 677
 678         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
 679         bprm->low_shift = bprm->hi_shift + bo;
 680
 681         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 682 }
 683
 684 /* String length checking wrapper */
 685 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 686                 struct probe_arg *parg, bool is_return, bool is_kprobe)
 687 {
 688         const char *t;
 689         int ret;
 690
 691         if (strlen(arg) > MAX_ARGSTR_LEN) {
 692                 pr_info("Argument is too long.: %s\n",  arg);
 693                 return -ENOSPC;
 694         }
 695         parg->comm = kstrdup(arg, GFP_KERNEL);
 696         if (!parg->comm) {
 697                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
 698                 return -ENOMEM;
 699         }
 700         t = strchr(parg->comm, ':');
 701         if (t) {
 702                 arg[t - parg->comm] = '\0';
 703                 t++;
 704         }
 705         parg->type = find_fetch_type(t);
 706         if (!parg->type) {
 707                 pr_info("Unsupported type: %s\n", t);
 708                 return -EINVAL;
 709         }
 710         parg->offset = *size;
 711         *size += parg->type->size;
 712         ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
 713
 714         if (ret >= 0 && t != NULL)
 715                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
 716
 717         if (ret >= 0) {
 718                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
 719                                                               parg->fetch.fn);
 720                 parg->fetch_size.data = parg->fetch.data;
 721         }
 722
 723         return ret;
 724 }
 725
 726 /* Return 1 if name is reserved or already used by another argument */
 727 int traceprobe_conflict_field_name(const char *name,
 728                                struct probe_arg *args, int narg)
 729 {
 730         int i;
 731
 732         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 733                 if (strcmp(reserved_field_names[i], name) == 0)
 734                         return 1;
 735
 736         for (i = 0; i < narg; i++)
 737                 if (strcmp(args[i].name, name) == 0)
 738                         return 1;
 739
 740         return 0;
 741 }
 742
 743 void traceprobe_update_arg(struct probe_arg *arg)
 744 {
 745         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 746                 update_bitfield_fetch_param(arg->fetch.data);
 747         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 748                 update_deref_fetch_param(arg->fetch.data);
 749         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 750                 update_symbol_cache(arg->fetch.data);
 751 }
 752
 753 void traceprobe_free_probe_arg(struct probe_arg *arg)
 754 {
 755         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 756                 free_bitfield_fetch_param(arg->fetch.data);
 757         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 758                 free_deref_fetch_param(arg->fetch.data);
 759         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 760                 free_symbol_cache(arg->fetch.data);
 761
 762         kfree(arg->name);
 763         kfree(arg->comm);
 764 }
 765
 766 int traceprobe_command(const char *buf, int (*createfn)(int, char **))
 767 {
 768         char **argv;
 769         int argc, ret;
 770
 771         argc = 0;
 772         ret = 0;
 773         argv = argv_split(GFP_KERNEL, buf, &argc);
 774         if (!argv)
 775                 return -ENOMEM;
 776
 777         if (argc)
 778                 ret = createfn(argc, argv);
 779
 780         argv_free(argv);
 781
 782         return ret;
 783 }
 784
 785 #define WRITE_BUFSIZE  4096
 786
 787 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
 788                                 size_t count, loff_t *ppos,
 789                                 int (*createfn)(int, char **))
 790 {
 791         char *kbuf, *tmp;
 792         int ret = 0;
 793         size_t done = 0;
 794         size_t size;
 795
 796         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 797         if (!kbuf)
 798                 return -ENOMEM;
 799
 800         while (done < count) {
 801                 size = count - done;
 802
 803                 if (size >= WRITE_BUFSIZE)
 804                         size = WRITE_BUFSIZE - 1;
 805
 806                 if (copy_from_user(kbuf, buffer + done, size)) {
 807                         ret = -EFAULT;
 808                         goto out;
 809                 }
 810                 kbuf[size] = '\0';
 811                 tmp = strchr(kbuf, '\n');
 812
 813                 if (tmp) {
 814                         *tmp = '\0';
 815                         size = tmp - kbuf + 1;
 816                 } else if (done + size < count) {
 817                         pr_warning("Line length is too long: "
 818                                    "Should be less than %d.", WRITE_BUFSIZE);
 819                         ret = -EINVAL;
 820                         goto out;
 821                 }
 822                 done += size;
 823                 /* Remove comments */
 824                 tmp = strchr(kbuf, '#');
 825
 826                 if (tmp)
 827                         *tmp = '\0';
 828
 829                 ret = traceprobe_command(kbuf, createfn);
 830                 if (ret)
 831                         goto out;
 832         }
 833         ret = done;
 834
 835 out:
 836         kfree(kbuf);
 837
 838         return ret;
 839 }