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  in basic type function template */
  39 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)                  \
  40 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, const char *name,  \
  41                                 void *data, void *ent)                  \
  42 {                                                                       \
  43         trace_seq_printf(s, " %s=" fmt, name, *(type *)data);           \
  44         return !trace_seq_has_overflowed(s);                            \
  45 }                                                                       \
  46 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;                          \
  47 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(tname));
  48
  49 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
  50 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
  51 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
  53 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
  54 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
  55 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
  56 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
  57 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
  58 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
  59 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
  60 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
  61
  62 /* Print type function for string type */
  63 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, const char *name,
  64                                  void *data, void *ent)
  65 {
  66         int len = *(u32 *)data >> 16;
  67
  68         if (!len)
  69                 trace_seq_printf(s, " %s=(fault)", name);
  70         else
  71                 trace_seq_printf(s, " %s=\"%s\"", name,
  72                                  (const char *)get_loc_data(data, ent));
  73         return !trace_seq_has_overflowed(s);
  74 }
  75 NOKPROBE_SYMBOL(PRINT_TYPE_FUNC_NAME(string));
  76
  77 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  78
  79 #define CHECK_FETCH_FUNCS(method, fn)                   \
  80         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
  81           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
  82           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
  83           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
  84           (FETCH_FUNC_NAME(method, string) == fn) ||    \
  85           (FETCH_FUNC_NAME(method, string_size) == fn)) \
  86          && (fn != NULL))
  87
  88 /* Data fetch function templates */
  89 #define DEFINE_FETCH_reg(type)                                          \
  90 void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \
  91 {                                                                       \
  92         *(type *)dest = (type)regs_get_register(regs,                   \
  93                                 (unsigned int)((unsigned long)offset)); \
  94 }                                                                       \
  95 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type));
  96 DEFINE_BASIC_FETCH_FUNCS(reg)
  97 /* No string on the register */
  98 #define fetch_reg_string        NULL
  99 #define fetch_reg_string_size   NULL
 100
 101 #define DEFINE_FETCH_retval(type)                                       \
 102 void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,                \
 103                                    void *dummy, void *dest)             \
 104 {                                                                       \
 105         *(type *)dest = (type)regs_return_value(regs);                  \
 106 }                                                                       \
 107 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type));
 108 DEFINE_BASIC_FETCH_FUNCS(retval)
 109 /* No string on the retval */
 110 #define fetch_retval_string             NULL
 111 #define fetch_retval_string_size        NULL
 112
 113 /* Dereference memory access function */
 114 struct deref_fetch_param {
 115         struct fetch_param      orig;
 116         long                    offset;
 117         fetch_func_t            fetch;
 118         fetch_func_t            fetch_size;
 119 };
 120
 121 #define DEFINE_FETCH_deref(type)                                        \
 122 void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,                 \
 123                                   void *data, void *dest)               \
 124 {                                                                       \
 125         struct deref_fetch_param *dprm = data;                          \
 126         unsigned long addr;                                             \
 127         call_fetch(&dprm->orig, regs, &addr);                           \
 128         if (addr) {                                                     \
 129                 addr += dprm->offset;                                   \
 130                 dprm->fetch(regs, (void *)addr, dest);                  \
 131         } else                                                          \
 132                 *(type *)dest = 0;                                      \
 133 }                                                                       \
 134 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type));
 135 DEFINE_BASIC_FETCH_FUNCS(deref)
 136 DEFINE_FETCH_deref(string)
 137
 138 void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs,
 139                                          void *data, void *dest)
 140 {
 141         struct deref_fetch_param *dprm = data;
 142         unsigned long addr;
 143
 144         call_fetch(&dprm->orig, regs, &addr);
 145         if (addr && dprm->fetch_size) {
 146                 addr += dprm->offset;
 147                 dprm->fetch_size(regs, (void *)addr, dest);
 148         } else
 149                 *(string_size *)dest = 0;
 150 }
 151 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size));
 152
 153 static void update_deref_fetch_param(struct deref_fetch_param *data)
 154 {
 155         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 156                 update_deref_fetch_param(data->orig.data);
 157         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 158                 update_symbol_cache(data->orig.data);
 159 }
 160 NOKPROBE_SYMBOL(update_deref_fetch_param);
 161
 162 static void free_deref_fetch_param(struct deref_fetch_param *data)
 163 {
 164         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 165                 free_deref_fetch_param(data->orig.data);
 166         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 167                 free_symbol_cache(data->orig.data);
 168         kfree(data);
 169 }
 170 NOKPROBE_SYMBOL(free_deref_fetch_param);
 171
 172 /* Bitfield fetch function */
 173 struct bitfield_fetch_param {
 174         struct fetch_param      orig;
 175         unsigned char           hi_shift;
 176         unsigned char           low_shift;
 177 };
 178
 179 #define DEFINE_FETCH_bitfield(type)                                     \
 180 void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,              \
 181                                      void *data, void *dest)            \
 182 {                                                                       \
 183         struct bitfield_fetch_param *bprm = data;                       \
 184         type buf = 0;                                                   \
 185         call_fetch(&bprm->orig, regs, &buf);                            \
 186         if (buf) {                                                      \
 187                 buf <<= bprm->hi_shift;                                 \
 188                 buf >>= bprm->low_shift;                                \
 189         }                                                               \
 190         *(type *)dest = buf;                                            \
 191 }                                                                       \
 192 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type));
 193 DEFINE_BASIC_FETCH_FUNCS(bitfield)
 194 #define fetch_bitfield_string           NULL
 195 #define fetch_bitfield_string_size      NULL
 196
 197 static void
 198 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
 199 {
 200         /*
 201          * Don't check the bitfield itself, because this must be the
 202          * last fetch function.
 203          */
 204         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 205                 update_deref_fetch_param(data->orig.data);
 206         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 207                 update_symbol_cache(data->orig.data);
 208 }
 209
 210 static void
 211 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
 212 {
 213         /*
 214          * Don't check the bitfield itself, because this must be the
 215          * last fetch function.
 216          */
 217         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 218                 free_deref_fetch_param(data->orig.data);
 219         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 220                 free_symbol_cache(data->orig.data);
 221
 222         kfree(data);
 223 }
 224
 225 void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs,
 226                                           void *data, void *dest)
 227 {
 228         int maxlen = get_rloc_len(*(u32 *)dest);
 229         u8 *dst = get_rloc_data(dest);
 230         long ret;
 231
 232         if (!maxlen)
 233                 return;
 234
 235         ret = strlcpy(dst, current->comm, maxlen);
 236         *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest));
 237 }
 238 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string));
 239
 240 void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs,
 241                                                void *data, void *dest)
 242 {
 243         *(u32 *)dest = strlen(current->comm) + 1;
 244 }
 245 NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size));
 246
 247 static const struct fetch_type *find_fetch_type(const char *type,
 248                                                 const struct fetch_type *ftbl)
 249 {
 250         int i;
 251
 252         if (!type)
 253                 type = DEFAULT_FETCH_TYPE_STR;
 254
 255         /* Special case: bitfield */
 256         if (*type == 'b') {
 257                 unsigned long bs;
 258
 259                 type = strchr(type, '/');
 260                 if (!type)
 261                         goto fail;
 262
 263                 type++;
 264                 if (kstrtoul(type, 0, &bs))
 265                         goto fail;
 266
 267                 switch (bs) {
 268                 case 8:
 269                         return find_fetch_type("u8", ftbl);
 270                 case 16:
 271                         return find_fetch_type("u16", ftbl);
 272                 case 32:
 273                         return find_fetch_type("u32", ftbl);
 274                 case 64:
 275                         return find_fetch_type("u64", ftbl);
 276                 default:
 277                         goto fail;
 278                 }
 279         }
 280
 281         for (i = 0; ftbl[i].name; i++) {
 282                 if (strcmp(type, ftbl[i].name) == 0)
 283                         return &ftbl[i];
 284         }
 285
 286 fail:
 287         return NULL;
 288 }
 289
 290 /* Special function : only accept unsigned long */
 291 static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest)
 292 {
 293         *(unsigned long *)dest = kernel_stack_pointer(regs);
 294 }
 295 NOKPROBE_SYMBOL(fetch_kernel_stack_address);
 296
 297 static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest)
 298 {
 299         *(unsigned long *)dest = user_stack_pointer(regs);
 300 }
 301 NOKPROBE_SYMBOL(fetch_user_stack_address);
 302
 303 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
 304                                             fetch_func_t orig_fn,
 305                                             const struct fetch_type *ftbl)
 306 {
 307         int i;
 308
 309         if (type != &ftbl[FETCH_TYPE_STRING])
 310                 return NULL;    /* Only string type needs size function */
 311
 312         for (i = 0; i < FETCH_MTD_END; i++)
 313                 if (type->fetch[i] == orig_fn)
 314                         return ftbl[FETCH_TYPE_STRSIZE].fetch[i];
 315
 316         WARN_ON(1);     /* This should not happen */
 317
 318         return NULL;
 319 }
 320
 321 /* Split symbol and offset. */
 322 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
 323 {
 324         char *tmp;
 325         int ret;
 326
 327         if (!offset)
 328                 return -EINVAL;
 329
 330         tmp = strchr(symbol, '+');
 331         if (tmp) {
 332                 /* skip sign because kstrtoul doesn't accept '+' */
 333                 ret = kstrtoul(tmp + 1, 0, offset);
 334                 if (ret)
 335                         return ret;
 336
 337                 *tmp = '\0';
 338         } else
 339                 *offset = 0;
 340
 341         return 0;
 342 }
 343
 344 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 345
 346 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 347                             struct fetch_param *f, bool is_return,
 348                             bool is_kprobe)
 349 {
 350         int ret = 0;
 351         unsigned long param;
 352
 353         if (strcmp(arg, "retval") == 0) {
 354                 if (is_return)
 355                         f->fn = t->fetch[FETCH_MTD_retval];
 356                 else
 357                         ret = -EINVAL;
 358         } else if (strncmp(arg, "stack", 5) == 0) {
 359                 if (arg[5] == '\0') {
 360                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR))
 361                                 return -EINVAL;
 362
 363                         if (is_kprobe)
 364                                 f->fn = fetch_kernel_stack_address;
 365                         else
 366                                 f->fn = fetch_user_stack_address;
 367                 } else if (isdigit(arg[5])) {
 368                         ret = kstrtoul(arg + 5, 10, &param);
 369                         if (ret || (is_kprobe && param > PARAM_MAX_STACK))
 370                                 ret = -EINVAL;
 371                         else {
 372                                 f->fn = t->fetch[FETCH_MTD_stack];
 373                                 f->data = (void *)param;
 374                         }
 375                 } else
 376                         ret = -EINVAL;
 377         } else if (strcmp(arg, "comm") == 0) {
 378                 if (strcmp(t->name, "string") != 0 &&
 379                     strcmp(t->name, "string_size") != 0)
 380                         return -EINVAL;
 381                 f->fn = t->fetch[FETCH_MTD_comm];
 382         } else
 383                 ret = -EINVAL;
 384
 385         return ret;
 386 }
 387
 388 /* Recursive argument parser */
 389 static int parse_probe_arg(char *arg, const struct fetch_type *t,
 390                      struct fetch_param *f, bool is_return, bool is_kprobe,
 391                      const struct fetch_type *ftbl)
 392 {
 393         unsigned long param;
 394         long offset;
 395         char *tmp;
 396         int ret = 0;
 397
 398         switch (arg[0]) {
 399         case '$':
 400                 ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe);
 401                 break;
 402
 403         case '%':       /* named register */
 404                 ret = regs_query_register_offset(arg + 1);
 405                 if (ret >= 0) {
 406                         f->fn = t->fetch[FETCH_MTD_reg];
 407                         f->data = (void *)(unsigned long)ret;
 408                         ret = 0;
 409                 }
 410                 break;
 411
 412         case '@':       /* memory, file-offset or symbol */
 413                 if (isdigit(arg[1])) {
 414                         ret = kstrtoul(arg + 1, 0, &param);
 415                         if (ret)
 416                                 break;
 417
 418                         f->fn = t->fetch[FETCH_MTD_memory];
 419                         f->data = (void *)param;
 420                 } else if (arg[1] == '+') {
 421                         /* kprobes don't support file offsets */
 422                         if (is_kprobe)
 423                                 return -EINVAL;
 424
 425                         ret = kstrtol(arg + 2, 0, &offset);
 426                         if (ret)
 427                                 break;
 428
 429                         f->fn = t->fetch[FETCH_MTD_file_offset];
 430                         f->data = (void *)offset;
 431                 } else {
 432                         /* uprobes don't support symbols */
 433                         if (!is_kprobe)
 434                                 return -EINVAL;
 435
 436                         ret = traceprobe_split_symbol_offset(arg + 1, &offset);
 437                         if (ret)
 438                                 break;
 439
 440                         f->data = alloc_symbol_cache(arg + 1, offset);
 441                         if (f->data)
 442                                 f->fn = t->fetch[FETCH_MTD_symbol];
 443                 }
 444                 break;
 445
 446         case '+':       /* deref memory */
 447                 arg++;  /* Skip '+', because kstrtol() rejects it. */
 448         case '-':
 449                 tmp = strchr(arg, '(');
 450                 if (!tmp)
 451                         break;
 452
 453                 *tmp = '\0';
 454                 ret = kstrtol(arg, 0, &offset);
 455
 456                 if (ret)
 457                         break;
 458
 459                 arg = tmp + 1;
 460                 tmp = strrchr(arg, ')');
 461
 462                 if (tmp) {
 463                         struct deref_fetch_param        *dprm;
 464                         const struct fetch_type         *t2;
 465
 466                         t2 = find_fetch_type(NULL, ftbl);
 467                         *tmp = '\0';
 468                         dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
 469
 470                         if (!dprm)
 471                                 return -ENOMEM;
 472
 473                         dprm->offset = offset;
 474                         dprm->fetch = t->fetch[FETCH_MTD_memory];
 475                         dprm->fetch_size = get_fetch_size_function(t,
 476                                                         dprm->fetch, ftbl);
 477                         ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
 478                                                         is_kprobe, ftbl);
 479                         if (ret)
 480                                 kfree(dprm);
 481                         else {
 482                                 f->fn = t->fetch[FETCH_MTD_deref];
 483                                 f->data = (void *)dprm;
 484                         }
 485                 }
 486                 break;
 487         }
 488         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
 489                 pr_info("%s type has no corresponding fetch method.\n", t->name);
 490                 ret = -EINVAL;
 491         }
 492
 493         return ret;
 494 }
 495
 496 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 497
 498 /* Bitfield type needs to be parsed into a fetch function */
 499 static int __parse_bitfield_probe_arg(const char *bf,
 500                                       const struct fetch_type *t,
 501                                       struct fetch_param *f)
 502 {
 503         struct bitfield_fetch_param *bprm;
 504         unsigned long bw, bo;
 505         char *tail;
 506
 507         if (*bf != 'b')
 508                 return 0;
 509
 510         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
 511         if (!bprm)
 512                 return -ENOMEM;
 513
 514         bprm->orig = *f;
 515         f->fn = t->fetch[FETCH_MTD_bitfield];
 516         f->data = (void *)bprm;
 517         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 518
 519         if (bw == 0 || *tail != '@')
 520                 return -EINVAL;
 521
 522         bf = tail + 1;
 523         bo = simple_strtoul(bf, &tail, 0);
 524
 525         if (tail == bf || *tail != '/')
 526                 return -EINVAL;
 527
 528         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
 529         bprm->low_shift = bprm->hi_shift + bo;
 530
 531         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 532 }
 533
 534 /* String length checking wrapper */
 535 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 536                 struct probe_arg *parg, bool is_return, bool is_kprobe,
 537                 const struct fetch_type *ftbl)
 538 {
 539         const char *t;
 540         int ret;
 541
 542         if (strlen(arg) > MAX_ARGSTR_LEN) {
 543                 pr_info("Argument is too long.: %s\n",  arg);
 544                 return -ENOSPC;
 545         }
 546         parg->comm = kstrdup(arg, GFP_KERNEL);
 547         if (!parg->comm) {
 548                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
 549                 return -ENOMEM;
 550         }
 551         t = strchr(parg->comm, ':');
 552         if (t) {
 553                 arg[t - parg->comm] = '\0';
 554                 t++;
 555         }
 556         /*
 557          * The default type of $comm should be "string", and it can't be
 558          * dereferenced.
 559          */
 560         if (!t && strcmp(arg, "$comm") == 0)
 561                 t = "string";
 562         parg->type = find_fetch_type(t, ftbl);
 563         if (!parg->type) {
 564                 pr_info("Unsupported type: %s\n", t);
 565                 return -EINVAL;
 566         }
 567         parg->offset = *size;
 568         *size += parg->type->size;
 569         ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return,
 570                               is_kprobe, ftbl);
 571
 572         if (ret >= 0 && t != NULL)
 573                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
 574
 575         if (ret >= 0) {
 576                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
 577                                                               parg->fetch.fn,
 578                                                               ftbl);
 579                 parg->fetch_size.data = parg->fetch.data;
 580         }
 581
 582         return ret;
 583 }
 584
 585 /* Return 1 if name is reserved or already used by another argument */
 586 int traceprobe_conflict_field_name(const char *name,
 587                                struct probe_arg *args, int narg)
 588 {
 589         int i;
 590
 591         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 592                 if (strcmp(reserved_field_names[i], name) == 0)
 593                         return 1;
 594
 595         for (i = 0; i < narg; i++)
 596                 if (strcmp(args[i].name, name) == 0)
 597                         return 1;
 598
 599         return 0;
 600 }
 601
 602 void traceprobe_update_arg(struct probe_arg *arg)
 603 {
 604         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 605                 update_bitfield_fetch_param(arg->fetch.data);
 606         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 607                 update_deref_fetch_param(arg->fetch.data);
 608         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 609                 update_symbol_cache(arg->fetch.data);
 610 }
 611
 612 void traceprobe_free_probe_arg(struct probe_arg *arg)
 613 {
 614         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 615                 free_bitfield_fetch_param(arg->fetch.data);
 616         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 617                 free_deref_fetch_param(arg->fetch.data);
 618         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 619                 free_symbol_cache(arg->fetch.data);
 620
 621         kfree(arg->name);
 622         kfree(arg->comm);
 623 }
 624
 625 int traceprobe_command(const char *buf, int (*createfn)(int, char **))
 626 {
 627         char **argv;
 628         int argc, ret;
 629
 630         argc = 0;
 631         ret = 0;
 632         argv = argv_split(GFP_KERNEL, buf, &argc);
 633         if (!argv)
 634                 return -ENOMEM;
 635
 636         if (argc)
 637                 ret = createfn(argc, argv);
 638
 639         argv_free(argv);
 640
 641         return ret;
 642 }
 643
 644 #define WRITE_BUFSIZE  4096
 645
 646 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
 647                                 size_t count, loff_t *ppos,
 648                                 int (*createfn)(int, char **))
 649 {
 650         char *kbuf, *tmp;
 651         int ret = 0;
 652         size_t done = 0;
 653         size_t size;
 654
 655         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 656         if (!kbuf)
 657                 return -ENOMEM;
 658
 659         while (done < count) {
 660                 size = count - done;
 661
 662                 if (size >= WRITE_BUFSIZE)
 663                         size = WRITE_BUFSIZE - 1;
 664
 665                 if (copy_from_user(kbuf, buffer + done, size)) {
 666                         ret = -EFAULT;
 667                         goto out;
 668                 }
 669                 kbuf[size] = '\0';
 670                 tmp = strchr(kbuf, '\n');
 671
 672                 if (tmp) {
 673                         *tmp = '\0';
 674                         size = tmp - kbuf + 1;
 675                 } else if (done + size < count) {
 676                         pr_warn("Line length is too long: Should be less than %d\n",
 677                                 WRITE_BUFSIZE);
 678                         ret = -EINVAL;
 679                         goto out;
 680                 }
 681                 done += size;
 682                 /* Remove comments */
 683                 tmp = strchr(kbuf, '#');
 684
 685                 if (tmp)
 686                         *tmp = '\0';
 687
 688                 ret = traceprobe_command(kbuf, createfn);
 689                 if (ret)
 690                         goto out;
 691         }
 692         ret = done;
 693
 694 out:
 695         kfree(kbuf);
 696
 697         return ret;
 698 }
 699
 700 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 701                            bool is_return)
 702 {
 703         int i;
 704         int pos = 0;
 705
 706         const char *fmt, *arg;
 707
 708         if (!is_return) {
 709                 fmt = "(%lx)";
 710                 arg = "REC->" FIELD_STRING_IP;
 711         } else {
 712                 fmt = "(%lx <- %lx)";
 713                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
 714         }
 715
 716         /* When len=0, we just calculate the needed length */
 717 #define LEN_OR_ZERO (len ? len - pos : 0)
 718
 719         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 720
 721         for (i = 0; i < tp->nr_args; i++) {
 722                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
 723                                 tp->args[i].name, tp->args[i].type->fmt);
 724         }
 725
 726         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
 727
 728         for (i = 0; i < tp->nr_args; i++) {
 729                 if (strcmp(tp->args[i].type->name, "string") == 0)
 730                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 731                                         ", __get_str(%s)",
 732                                         tp->args[i].name);
 733                 else
 734                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
 735                                         tp->args[i].name);
 736         }
 737
 738 #undef LEN_OR_ZERO
 739
 740         /* return the length of print_fmt */
 741         return pos;
 742 }
 743
 744 int set_print_fmt(struct trace_probe *tp, bool is_return)
 745 {
 746         int len;
 747         char *print_fmt;
 748
 749         /* First: called with 0 length to calculate the needed length */
 750         len = __set_print_fmt(tp, NULL, 0, is_return);
 751         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 752         if (!print_fmt)
 753                 return -ENOMEM;
 754
 755         /* Second: actually write the @print_fmt */
 756         __set_print_fmt(tp, print_fmt, len + 1, is_return);
 757         tp->call.print_fmt = print_fmt;
 758
 759         return 0;
 760 }