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