Pileus Git - ~andy/linux/blob - 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 __kprobes int PRINT_TYPE_FUNC_NAME(type)(struct trace_seq *s,   \
  41                                                 const char *name,       \
  42                                                 void *data, void *ent)  \
  43 {                                                                       \
  44         return trace_seq_printf(s, " %s=" fmt, name, *(type *)data);    \
  45 }                                                                       \
  46 const char PRINT_TYPE_FMT_NAME(type)[] = fmt;
  47
  48 DEFINE_BASIC_PRINT_TYPE_FUNC(u8 , "0x%x")
  49 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, "0x%x")
  50 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, "0x%x")
  51 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, "0x%Lx")
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  "%d")
  53 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, "%d")
  54 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, "%d")
  55 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, "%Ld")
  56
  57 /* For defining macros, define string/string_size types */
  58 typedef u32 string;
  59 typedef u32 string_size;
  60
  61 /* Print type function for string type */
  62 __kprobes int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s,
  63                                                   const char *name,
  64                                                   void *data, void *ent)
  65 {
  66         int len = *(u32 *)data >> 16;
  67
  68         if (!len)
  69                 return trace_seq_printf(s, " %s=(fault)", name);
  70         else
  71                 return trace_seq_printf(s, " %s=\"%s\"", name,
  72                                         (const char *)get_loc_data(data, ent));
  73 }
  74
  75 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  76
  77 #define FETCH_FUNC_NAME(method, type)   fetch_##method##_##type
  78 /*
  79  * Define macro for basic types - we don't need to define s* types, because
  80  * we have to care only about bitwidth at recording time.
  81  */
  82 #define DEFINE_BASIC_FETCH_FUNCS(method) \
  83 DEFINE_FETCH_##method(u8)               \
  84 DEFINE_FETCH_##method(u16)              \
  85 DEFINE_FETCH_##method(u32)              \
  86 DEFINE_FETCH_##method(u64)
  87
  88 #define CHECK_FETCH_FUNCS(method, fn)                   \
  89         (((FETCH_FUNC_NAME(method, u8) == fn) ||        \
  90           (FETCH_FUNC_NAME(method, u16) == fn) ||       \
  91           (FETCH_FUNC_NAME(method, u32) == fn) ||       \
  92           (FETCH_FUNC_NAME(method, u64) == fn) ||       \
  93           (FETCH_FUNC_NAME(method, string) == fn) ||    \
  94           (FETCH_FUNC_NAME(method, string_size) == fn)) \
  95          && (fn != NULL))
  96
  97 /* Data fetch function templates */
  98 #define DEFINE_FETCH_reg(type)                                          \
  99 __kprobes void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs,         \
 100                                         void *offset, void *dest)       \
 101 {                                                                       \
 102         *(type *)dest = (type)regs_get_register(regs,                   \
 103                                 (unsigned int)((unsigned long)offset)); \
 104 }
 105 DEFINE_BASIC_FETCH_FUNCS(reg)
 106 /* No string on the register */
 107 #define fetch_reg_string        NULL
 108 #define fetch_reg_string_size   NULL
 109
 110 #define DEFINE_FETCH_stack(type)                                        \
 111 __kprobes void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs,       \
 112                                           void *offset, void *dest)     \
 113 {                                                                       \
 114         *(type *)dest = (type)regs_get_kernel_stack_nth(regs,           \
 115                                 (unsigned int)((unsigned long)offset)); \
 116 }
 117 DEFINE_BASIC_FETCH_FUNCS(stack)
 118 /* No string on the stack entry */
 119 #define fetch_stack_string      NULL
 120 #define fetch_stack_string_size NULL
 121
 122 #define DEFINE_FETCH_retval(type)                                       \
 123 __kprobes void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs,      \
 124                                           void *dummy, void *dest)      \
 125 {                                                                       \
 126         *(type *)dest = (type)regs_return_value(regs);                  \
 127 }
 128 DEFINE_BASIC_FETCH_FUNCS(retval)
 129 /* No string on the retval */
 130 #define fetch_retval_string             NULL
 131 #define fetch_retval_string_size        NULL
 132
 133 #define DEFINE_FETCH_memory(type)                                       \
 134 __kprobes void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs,      \
 135                                           void *addr, void *dest)       \
 136 {                                                                       \
 137         type retval;                                                    \
 138         if (probe_kernel_address(addr, retval))                         \
 139                 *(type *)dest = 0;                                      \
 140         else                                                            \
 141                 *(type *)dest = retval;                                 \
 142 }
 143 DEFINE_BASIC_FETCH_FUNCS(memory)
 144 /*
 145  * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max
 146  * length and relative data location.
 147  */
 148 __kprobes void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs,
 149                                                       void *addr, void *dest)
 150 {
 151         long ret;
 152         int maxlen = get_rloc_len(*(u32 *)dest);
 153         u8 *dst = get_rloc_data(dest);
 154         u8 *src = addr;
 155         mm_segment_t old_fs = get_fs();
 156
 157         if (!maxlen)
 158                 return;
 159
 160         /*
 161          * Try to get string again, since the string can be changed while
 162          * probing.
 163          */
 164         set_fs(KERNEL_DS);
 165         pagefault_disable();
 166
 167         do
 168                 ret = __copy_from_user_inatomic(dst++, src++, 1);
 169         while (dst[-1] && ret == 0 && src - (u8 *)addr < maxlen);
 170
 171         dst[-1] = '\0';
 172         pagefault_enable();
 173         set_fs(old_fs);
 174
 175         if (ret < 0) {  /* Failed to fetch string */
 176                 ((u8 *)get_rloc_data(dest))[0] = '\0';
 177                 *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest));
 178         } else {
 179                 *(u32 *)dest = make_data_rloc(src - (u8 *)addr,
 180                                               get_rloc_offs(*(u32 *)dest));
 181         }
 182 }
 183
 184 /* Return the length of string -- including null terminal byte */
 185 __kprobes void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs,
 186                                                         void *addr, void *dest)
 187 {
 188         mm_segment_t old_fs;
 189         int ret, len = 0;
 190         u8 c;
 191
 192         old_fs = get_fs();
 193         set_fs(KERNEL_DS);
 194         pagefault_disable();
 195
 196         do {
 197                 ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1);
 198                 len++;
 199         } while (c && ret == 0 && len < MAX_STRING_SIZE);
 200
 201         pagefault_enable();
 202         set_fs(old_fs);
 203
 204         if (ret < 0)    /* Failed to check the length */
 205                 *(u32 *)dest = 0;
 206         else
 207                 *(u32 *)dest = len;
 208 }
 209
 210 /* Memory fetching by symbol */
 211 struct symbol_cache {
 212         char            *symbol;
 213         long            offset;
 214         unsigned long   addr;
 215 };
 216
 217 static unsigned long update_symbol_cache(struct symbol_cache *sc)
 218 {
 219         sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol);
 220
 221         if (sc->addr)
 222                 sc->addr += sc->offset;
 223
 224         return sc->addr;
 225 }
 226
 227 static void free_symbol_cache(struct symbol_cache *sc)
 228 {
 229         kfree(sc->symbol);
 230         kfree(sc);
 231 }
 232
 233 static struct symbol_cache *alloc_symbol_cache(const char *sym, long offset)
 234 {
 235         struct symbol_cache *sc;
 236
 237         if (!sym || strlen(sym) == 0)
 238                 return NULL;
 239
 240         sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL);
 241         if (!sc)
 242                 return NULL;
 243
 244         sc->symbol = kstrdup(sym, GFP_KERNEL);
 245         if (!sc->symbol) {
 246                 kfree(sc);
 247                 return NULL;
 248         }
 249         sc->offset = offset;
 250         update_symbol_cache(sc);
 251
 252         return sc;
 253 }
 254
 255 #define DEFINE_FETCH_symbol(type)                                       \
 256 __kprobes void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs,      \
 257                                           void *data, void *dest)       \
 258 {                                                                       \
 259         struct symbol_cache *sc = data;                                 \
 260         if (sc->addr)                                                   \
 261                 fetch_memory_##type(regs, (void *)sc->addr, dest);      \
 262         else                                                            \
 263                 *(type *)dest = 0;                                      \
 264 }
 265 DEFINE_BASIC_FETCH_FUNCS(symbol)
 266 DEFINE_FETCH_symbol(string)
 267 DEFINE_FETCH_symbol(string_size)
 268
 269 /* Dereference memory access function */
 270 struct deref_fetch_param {
 271         struct fetch_param      orig;
 272         long                    offset;
 273 };
 274
 275 #define DEFINE_FETCH_deref(type)                                        \
 276 __kprobes void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs,       \
 277                                             void *data, void *dest)     \
 278 {                                                                       \
 279         struct deref_fetch_param *dprm = data;                          \
 280         unsigned long addr;                                             \
 281         call_fetch(&dprm->orig, regs, &addr);                           \
 282         if (addr) {                                                     \
 283                 addr += dprm->offset;                                   \
 284                 fetch_memory_##type(regs, (void *)addr, dest);          \
 285         } else                                                          \
 286                 *(type *)dest = 0;                                      \
 287 }
 288 DEFINE_BASIC_FETCH_FUNCS(deref)
 289 DEFINE_FETCH_deref(string)
 290 DEFINE_FETCH_deref(string_size)
 291
 292 static __kprobes void update_deref_fetch_param(struct deref_fetch_param *data)
 293 {
 294         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 295                 update_deref_fetch_param(data->orig.data);
 296         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 297                 update_symbol_cache(data->orig.data);
 298 }
 299
 300 static __kprobes void free_deref_fetch_param(struct deref_fetch_param *data)
 301 {
 302         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 303                 free_deref_fetch_param(data->orig.data);
 304         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 305                 free_symbol_cache(data->orig.data);
 306         kfree(data);
 307 }
 308
 309 /* Bitfield fetch function */
 310 struct bitfield_fetch_param {
 311         struct fetch_param      orig;
 312         unsigned char           hi_shift;
 313         unsigned char           low_shift;
 314 };
 315
 316 #define DEFINE_FETCH_bitfield(type)                                     \
 317 __kprobes void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs,    \
 318                                             void *data, void *dest)     \
 319 {                                                                       \
 320         struct bitfield_fetch_param *bprm = data;                       \
 321         type buf = 0;                                                   \
 322         call_fetch(&bprm->orig, regs, &buf);                            \
 323         if (buf) {                                                      \
 324                 buf <<= bprm->hi_shift;                                 \
 325                 buf >>= bprm->low_shift;                                \
 326         }                                                               \
 327         *(type *)dest = buf;                                            \
 328 }
 329
 330 DEFINE_BASIC_FETCH_FUNCS(bitfield)
 331 #define fetch_bitfield_string           NULL
 332 #define fetch_bitfield_string_size      NULL
 333
 334 static __kprobes void
 335 update_bitfield_fetch_param(struct bitfield_fetch_param *data)
 336 {
 337         /*
 338          * Don't check the bitfield itself, because this must be the
 339          * last fetch function.
 340          */
 341         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 342                 update_deref_fetch_param(data->orig.data);
 343         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 344                 update_symbol_cache(data->orig.data);
 345 }
 346
 347 static __kprobes void
 348 free_bitfield_fetch_param(struct bitfield_fetch_param *data)
 349 {
 350         /*
 351          * Don't check the bitfield itself, because this must be the
 352          * last fetch function.
 353          */
 354         if (CHECK_FETCH_FUNCS(deref, data->orig.fn))
 355                 free_deref_fetch_param(data->orig.data);
 356         else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn))
 357                 free_symbol_cache(data->orig.data);
 358
 359         kfree(data);
 360 }
 361
 362 /* Fetch type information table */
 363 static const struct fetch_type fetch_type_table[] = {
 364         /* Special types */
 365         [FETCH_TYPE_STRING] = __ASSIGN_FETCH_TYPE("string", string, string,
 366                                         sizeof(u32), 1, "__data_loc char[]"),
 367         [FETCH_TYPE_STRSIZE] = __ASSIGN_FETCH_TYPE("string_size", u32,
 368                                         string_size, sizeof(u32), 0, "u32"),
 369         /* Basic types */
 370         ASSIGN_FETCH_TYPE(u8,  u8,  0),
 371         ASSIGN_FETCH_TYPE(u16, u16, 0),
 372         ASSIGN_FETCH_TYPE(u32, u32, 0),
 373         ASSIGN_FETCH_TYPE(u64, u64, 0),
 374         ASSIGN_FETCH_TYPE(s8,  u8,  1),
 375         ASSIGN_FETCH_TYPE(s16, u16, 1),
 376         ASSIGN_FETCH_TYPE(s32, u32, 1),
 377         ASSIGN_FETCH_TYPE(s64, u64, 1),
 378 };
 379
 380 static const struct fetch_type *find_fetch_type(const char *type)
 381 {
 382         int i;
 383
 384         if (!type)
 385                 type = DEFAULT_FETCH_TYPE_STR;
 386
 387         /* Special case: bitfield */
 388         if (*type == 'b') {
 389                 unsigned long bs;
 390
 391                 type = strchr(type, '/');
 392                 if (!type)
 393                         goto fail;
 394
 395                 type++;
 396                 if (kstrtoul(type, 0, &bs))
 397                         goto fail;
 398
 399                 switch (bs) {
 400                 case 8:
 401                         return find_fetch_type("u8");
 402                 case 16:
 403                         return find_fetch_type("u16");
 404                 case 32:
 405                         return find_fetch_type("u32");
 406                 case 64:
 407                         return find_fetch_type("u64");
 408                 default:
 409                         goto fail;
 410                 }
 411         }
 412
 413         for (i = 0; i < ARRAY_SIZE(fetch_type_table); i++)
 414                 if (strcmp(type, fetch_type_table[i].name) == 0)
 415                         return &fetch_type_table[i];
 416
 417 fail:
 418         return NULL;
 419 }
 420
 421 /* Special function : only accept unsigned long */
 422 static __kprobes void fetch_stack_address(struct pt_regs *regs,
 423                                         void *dummy, void *dest)
 424 {
 425         *(unsigned long *)dest = kernel_stack_pointer(regs);
 426 }
 427
 428 static fetch_func_t get_fetch_size_function(const struct fetch_type *type,
 429                                         fetch_func_t orig_fn)
 430 {
 431         int i;
 432
 433         if (type != &fetch_type_table[FETCH_TYPE_STRING])
 434                 return NULL;    /* Only string type needs size function */
 435
 436         for (i = 0; i < FETCH_MTD_END; i++)
 437                 if (type->fetch[i] == orig_fn)
 438                         return fetch_type_table[FETCH_TYPE_STRSIZE].fetch[i];
 439
 440         WARN_ON(1);     /* This should not happen */
 441
 442         return NULL;
 443 }
 444
 445 /* Split symbol and offset. */
 446 int traceprobe_split_symbol_offset(char *symbol, unsigned long *offset)
 447 {
 448         char *tmp;
 449         int ret;
 450
 451         if (!offset)
 452                 return -EINVAL;
 453
 454         tmp = strchr(symbol, '+');
 455         if (tmp) {
 456                 /* skip sign because kstrtoul doesn't accept '+' */
 457                 ret = kstrtoul(tmp + 1, 0, offset);
 458                 if (ret)
 459                         return ret;
 460
 461                 *tmp = '\0';
 462         } else
 463                 *offset = 0;
 464
 465         return 0;
 466 }
 467
 468 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 469
 470 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 471                             struct fetch_param *f, bool is_return)
 472 {
 473         int ret = 0;
 474         unsigned long param;
 475
 476         if (strcmp(arg, "retval") == 0) {
 477                 if (is_return)
 478                         f->fn = t->fetch[FETCH_MTD_retval];
 479                 else
 480                         ret = -EINVAL;
 481         } else if (strncmp(arg, "stack", 5) == 0) {
 482                 if (arg[5] == '\0') {
 483                         if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR) == 0)
 484                                 f->fn = fetch_stack_address;
 485                         else
 486                                 ret = -EINVAL;
 487                 } else if (isdigit(arg[5])) {
 488                         ret = kstrtoul(arg + 5, 10, &param);
 489                         if (ret || param > PARAM_MAX_STACK)
 490                                 ret = -EINVAL;
 491                         else {
 492                                 f->fn = t->fetch[FETCH_MTD_stack];
 493                                 f->data = (void *)param;
 494                         }
 495                 } else
 496                         ret = -EINVAL;
 497         } else
 498                 ret = -EINVAL;
 499
 500         return ret;
 501 }
 502
 503 /* Recursive argument parser */
 504 static int parse_probe_arg(char *arg, const struct fetch_type *t,
 505                      struct fetch_param *f, bool is_return, bool is_kprobe)
 506 {
 507         unsigned long param;
 508         long offset;
 509         char *tmp;
 510         int ret;
 511
 512         ret = 0;
 513
 514         /* Until uprobe_events supports only reg arguments */
 515         if (!is_kprobe && arg[0] != '%')
 516                 return -EINVAL;
 517
 518         switch (arg[0]) {
 519         case '$':
 520                 ret = parse_probe_vars(arg + 1, t, f, is_return);
 521                 break;
 522
 523         case '%':       /* named register */
 524                 ret = regs_query_register_offset(arg + 1);
 525                 if (ret >= 0) {
 526                         f->fn = t->fetch[FETCH_MTD_reg];
 527                         f->data = (void *)(unsigned long)ret;
 528                         ret = 0;
 529                 }
 530                 break;
 531
 532         case '@':       /* memory or symbol */
 533                 if (isdigit(arg[1])) {
 534                         ret = kstrtoul(arg + 1, 0, &param);
 535                         if (ret)
 536                                 break;
 537
 538                         f->fn = t->fetch[FETCH_MTD_memory];
 539                         f->data = (void *)param;
 540                 } else {
 541                         ret = traceprobe_split_symbol_offset(arg + 1, &offset);
 542                         if (ret)
 543                                 break;
 544
 545                         f->data = alloc_symbol_cache(arg + 1, offset);
 546                         if (f->data)
 547                                 f->fn = t->fetch[FETCH_MTD_symbol];
 548                 }
 549                 break;
 550
 551         case '+':       /* deref memory */
 552                 arg++;  /* Skip '+', because kstrtol() rejects it. */
 553         case '-':
 554                 tmp = strchr(arg, '(');
 555                 if (!tmp)
 556                         break;
 557
 558                 *tmp = '\0';
 559                 ret = kstrtol(arg, 0, &offset);
 560
 561                 if (ret)
 562                         break;
 563
 564                 arg = tmp + 1;
 565                 tmp = strrchr(arg, ')');
 566
 567                 if (tmp) {
 568                         struct deref_fetch_param        *dprm;
 569                         const struct fetch_type         *t2;
 570
 571                         t2 = find_fetch_type(NULL);
 572                         *tmp = '\0';
 573                         dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL);
 574
 575                         if (!dprm)
 576                                 return -ENOMEM;
 577
 578                         dprm->offset = offset;
 579                         ret = parse_probe_arg(arg, t2, &dprm->orig, is_return,
 580                                                         is_kprobe);
 581                         if (ret)
 582                                 kfree(dprm);
 583                         else {
 584                                 f->fn = t->fetch[FETCH_MTD_deref];
 585                                 f->data = (void *)dprm;
 586                         }
 587                 }
 588                 break;
 589         }
 590         if (!ret && !f->fn) {   /* Parsed, but do not find fetch method */
 591                 pr_info("%s type has no corresponding fetch method.\n", t->name);
 592                 ret = -EINVAL;
 593         }
 594
 595         return ret;
 596 }
 597
 598 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 599
 600 /* Bitfield type needs to be parsed into a fetch function */
 601 static int __parse_bitfield_probe_arg(const char *bf,
 602                                       const struct fetch_type *t,
 603                                       struct fetch_param *f)
 604 {
 605         struct bitfield_fetch_param *bprm;
 606         unsigned long bw, bo;
 607         char *tail;
 608
 609         if (*bf != 'b')
 610                 return 0;
 611
 612         bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
 613         if (!bprm)
 614                 return -ENOMEM;
 615
 616         bprm->orig = *f;
 617         f->fn = t->fetch[FETCH_MTD_bitfield];
 618         f->data = (void *)bprm;
 619         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 620
 621         if (bw == 0 || *tail != '@')
 622                 return -EINVAL;
 623
 624         bf = tail + 1;
 625         bo = simple_strtoul(bf, &tail, 0);
 626
 627         if (tail == bf || *tail != '/')
 628                 return -EINVAL;
 629
 630         bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo);
 631         bprm->low_shift = bprm->hi_shift + bo;
 632
 633         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 634 }
 635
 636 /* String length checking wrapper */
 637 int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
 638                 struct probe_arg *parg, bool is_return, bool is_kprobe)
 639 {
 640         const char *t;
 641         int ret;
 642
 643         if (strlen(arg) > MAX_ARGSTR_LEN) {
 644                 pr_info("Argument is too long.: %s\n",  arg);
 645                 return -ENOSPC;
 646         }
 647         parg->comm = kstrdup(arg, GFP_KERNEL);
 648         if (!parg->comm) {
 649                 pr_info("Failed to allocate memory for command '%s'.\n", arg);
 650                 return -ENOMEM;
 651         }
 652         t = strchr(parg->comm, ':');
 653         if (t) {
 654                 arg[t - parg->comm] = '\0';
 655                 t++;
 656         }
 657         parg->type = find_fetch_type(t);
 658         if (!parg->type) {
 659                 pr_info("Unsupported type: %s\n", t);
 660                 return -EINVAL;
 661         }
 662         parg->offset = *size;
 663         *size += parg->type->size;
 664         ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, is_kprobe);
 665
 666         if (ret >= 0 && t != NULL)
 667                 ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);
 668
 669         if (ret >= 0) {
 670                 parg->fetch_size.fn = get_fetch_size_function(parg->type,
 671                                                               parg->fetch.fn);
 672                 parg->fetch_size.data = parg->fetch.data;
 673         }
 674
 675         return ret;
 676 }
 677
 678 /* Return 1 if name is reserved or already used by another argument */
 679 int traceprobe_conflict_field_name(const char *name,
 680                                struct probe_arg *args, int narg)
 681 {
 682         int i;
 683
 684         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 685                 if (strcmp(reserved_field_names[i], name) == 0)
 686                         return 1;
 687
 688         for (i = 0; i < narg; i++)
 689                 if (strcmp(args[i].name, name) == 0)
 690                         return 1;
 691
 692         return 0;
 693 }
 694
 695 void traceprobe_update_arg(struct probe_arg *arg)
 696 {
 697         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 698                 update_bitfield_fetch_param(arg->fetch.data);
 699         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 700                 update_deref_fetch_param(arg->fetch.data);
 701         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 702                 update_symbol_cache(arg->fetch.data);
 703 }
 704
 705 void traceprobe_free_probe_arg(struct probe_arg *arg)
 706 {
 707         if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn))
 708                 free_bitfield_fetch_param(arg->fetch.data);
 709         else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn))
 710                 free_deref_fetch_param(arg->fetch.data);
 711         else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn))
 712                 free_symbol_cache(arg->fetch.data);
 713
 714         kfree(arg->name);
 715         kfree(arg->comm);
 716 }
 717
 718 int traceprobe_command(const char *buf, int (*createfn)(int, char **))
 719 {
 720         char **argv;
 721         int argc, ret;
 722
 723         argc = 0;
 724         ret = 0;
 725         argv = argv_split(GFP_KERNEL, buf, &argc);
 726         if (!argv)
 727                 return -ENOMEM;
 728
 729         if (argc)
 730                 ret = createfn(argc, argv);
 731
 732         argv_free(argv);
 733
 734         return ret;
 735 }
 736
 737 #define WRITE_BUFSIZE  4096
 738
 739 ssize_t traceprobe_probes_write(struct file *file, const char __user *buffer,
 740                                 size_t count, loff_t *ppos,
 741                                 int (*createfn)(int, char **))
 742 {
 743         char *kbuf, *tmp;
 744         int ret = 0;
 745         size_t done = 0;
 746         size_t size;
 747
 748         kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
 749         if (!kbuf)
 750                 return -ENOMEM;
 751
 752         while (done < count) {
 753                 size = count - done;
 754
 755                 if (size >= WRITE_BUFSIZE)
 756                         size = WRITE_BUFSIZE - 1;
 757
 758                 if (copy_from_user(kbuf, buffer + done, size)) {
 759                         ret = -EFAULT;
 760                         goto out;
 761                 }
 762                 kbuf[size] = '\0';
 763                 tmp = strchr(kbuf, '\n');
 764
 765                 if (tmp) {
 766                         *tmp = '\0';
 767                         size = tmp - kbuf + 1;
 768                 } else if (done + size < count) {
 769                         pr_warning("Line length is too long: "
 770                                    "Should be less than %d.", WRITE_BUFSIZE);
 771                         ret = -EINVAL;
 772                         goto out;
 773                 }
 774                 done += size;
 775                 /* Remove comments */
 776                 tmp = strchr(kbuf, '#');
 777
 778                 if (tmp)
 779                         *tmp = '\0';
 780
 781                 ret = traceprobe_command(kbuf, createfn);
 782                 if (ret)
 783                         goto out;
 784         }
 785         ret = done;
 786
 787 out:
 788         kfree(kbuf);
 789
 790         return ret;
 791 }
 792
 793 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 794                            bool is_return)
 795 {
 796         int i;
 797         int pos = 0;
 798
 799         const char *fmt, *arg;
 800
 801         if (!is_return) {
 802                 fmt = "(%lx)";
 803                 arg = "REC->" FIELD_STRING_IP;
 804         } else {
 805                 fmt = "(%lx <- %lx)";
 806                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
 807         }
 808
 809         /* When len=0, we just calculate the needed length */
 810 #define LEN_OR_ZERO (len ? len - pos : 0)
 811
 812         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 813
 814         for (i = 0; i < tp->nr_args; i++) {
 815                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s",
 816                                 tp->args[i].name, tp->args[i].type->fmt);
 817         }
 818
 819         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
 820
 821         for (i = 0; i < tp->nr_args; i++) {
 822                 if (strcmp(tp->args[i].type->name, "string") == 0)
 823                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 824                                         ", __get_str(%s)",
 825                                         tp->args[i].name);
 826                 else
 827                         pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
 828                                         tp->args[i].name);
 829         }
 830
 831 #undef LEN_OR_ZERO
 832
 833         /* return the length of print_fmt */
 834         return pos;
 835 }
 836
 837 int set_print_fmt(struct trace_probe *tp, bool is_return)
 838 {
 839         int len;
 840         char *print_fmt;
 841
 842         /* First: called with 0 length to calculate the needed length */
 843         len = __set_print_fmt(tp, NULL, 0, is_return);
 844         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 845         if (!print_fmt)
 846                 return -ENOMEM;
 847
 848         /* Second: actually write the @print_fmt */
 849         __set_print_fmt(tp, print_fmt, len + 1, is_return);
 850         tp->call.print_fmt = print_fmt;
 851
 852         return 0;
 853 }