kernel/trace/trace_probe.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Common code for probe-based Dynamic events.
   4  *
   5  * This code was copied from kernel/trace/trace_kprobe.c written by
   6  * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
   7  *
   8  * Updates to make this generic:
   9  * Copyright (C) IBM Corporation, 2010-2011
  10  * Author:     Srikar Dronamraju
  11  */
  12 #define pr_fmt(fmt)     "trace_probe: " fmt
  13
  14 #include "trace_probe.h"
  15
  16 #undef C
  17 #define C(a, b)         b
  18
  19 static const char *trace_probe_err_text[] = { ERRORS };
  20
  21 static const char *reserved_field_names[] = {
  22         "common_type",
  23         "common_flags",
  24         "common_preempt_count",
  25         "common_pid",
  26         "common_tgid",
  27         FIELD_STRING_IP,
  28         FIELD_STRING_RETIP,
  29         FIELD_STRING_FUNC,
  30 };
  31
  32 /* Printing  in basic type function template */
  33 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt)                  \
  34 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\
  35 {                                                                       \
  36         trace_seq_printf(s, fmt, *(type *)data);                        \
  37         return !trace_seq_has_overflowed(s);                            \
  38 }                                                                       \
  39 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt;
  40
  41 DEFINE_BASIC_PRINT_TYPE_FUNC(u8,  u8,  "%u")
  42 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u")
  43 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u")
  44 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu")
  45 DEFINE_BASIC_PRINT_TYPE_FUNC(s8,  s8,  "%d")
  46 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d")
  47 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d")
  48 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld")
  49 DEFINE_BASIC_PRINT_TYPE_FUNC(x8,  u8,  "0x%x")
  50 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x")
  51 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x")
  52 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx")
  53
  54 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent)
  55 {
  56         trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data);
  57         return !trace_seq_has_overflowed(s);
  58 }
  59 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS";
  60
  61 /* Print type function for string type */
  62 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)
  63 {
  64         int len = *(u32 *)data >> 16;
  65
  66         if (!len)
  67                 trace_seq_puts(s, "(fault)");
  68         else
  69                 trace_seq_printf(s, "\"%s\"",
  70                                  (const char *)get_loc_data(data, ent));
  71         return !trace_seq_has_overflowed(s);
  72 }
  73
  74 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\"";
  75
  76 /* Fetch type information table */
  77 static const struct fetch_type probe_fetch_types[] = {
  78         /* Special types */
  79         __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1,
  80                             "__data_loc char[]"),
  81         __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1,
  82                             "__data_loc char[]"),
  83         /* Basic types */
  84         ASSIGN_FETCH_TYPE(u8,  u8,  0),
  85         ASSIGN_FETCH_TYPE(u16, u16, 0),
  86         ASSIGN_FETCH_TYPE(u32, u32, 0),
  87         ASSIGN_FETCH_TYPE(u64, u64, 0),
  88         ASSIGN_FETCH_TYPE(s8,  u8,  1),
  89         ASSIGN_FETCH_TYPE(s16, u16, 1),
  90         ASSIGN_FETCH_TYPE(s32, u32, 1),
  91         ASSIGN_FETCH_TYPE(s64, u64, 1),
  92         ASSIGN_FETCH_TYPE_ALIAS(x8,  u8,  u8,  0),
  93         ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0),
  94         ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0),
  95         ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0),
  96         ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0),
  97
  98         ASSIGN_FETCH_TYPE_END
  99 };
 100
 101 static const struct fetch_type *find_fetch_type(const char *type)
 102 {
 103         int i;
 104
 105         if (!type)
 106                 type = DEFAULT_FETCH_TYPE_STR;
 107
 108         /* Special case: bitfield */
 109         if (*type == 'b') {
 110                 unsigned long bs;
 111
 112                 type = strchr(type, '/');
 113                 if (!type)
 114                         goto fail;
 115
 116                 type++;
 117                 if (kstrtoul(type, 0, &bs))
 118                         goto fail;
 119
 120                 switch (bs) {
 121                 case 8:
 122                         return find_fetch_type("u8");
 123                 case 16:
 124                         return find_fetch_type("u16");
 125                 case 32:
 126                         return find_fetch_type("u32");
 127                 case 64:
 128                         return find_fetch_type("u64");
 129                 default:
 130                         goto fail;
 131                 }
 132         }
 133
 134         for (i = 0; probe_fetch_types[i].name; i++) {
 135                 if (strcmp(type, probe_fetch_types[i].name) == 0)
 136                         return &probe_fetch_types[i];
 137         }
 138
 139 fail:
 140         return NULL;
 141 }
 142
 143 static struct trace_probe_log trace_probe_log;
 144
 145 void trace_probe_log_init(const char *subsystem, int argc, const char **argv)
 146 {
 147         trace_probe_log.subsystem = subsystem;
 148         trace_probe_log.argc = argc;
 149         trace_probe_log.argv = argv;
 150         trace_probe_log.index = 0;
 151 }
 152
 153 void trace_probe_log_clear(void)
 154 {
 155         memset(&trace_probe_log, 0, sizeof(trace_probe_log));
 156 }
 157
 158 void trace_probe_log_set_index(int index)
 159 {
 160         trace_probe_log.index = index;
 161 }
 162
 163 void __trace_probe_log_err(int offset, int err_type)
 164 {
 165         char *command, *p;
 166         int i, len = 0, pos = 0;
 167
 168         if (!trace_probe_log.argv)
 169                 return;
 170
 171         /* Recalculate the length and allocate buffer */
 172         for (i = 0; i < trace_probe_log.argc; i++) {
 173                 if (i == trace_probe_log.index)
 174                         pos = len;
 175                 len += strlen(trace_probe_log.argv[i]) + 1;
 176         }
 177         command = kzalloc(len, GFP_KERNEL);
 178         if (!command)
 179                 return;
 180
 181         if (trace_probe_log.index >= trace_probe_log.argc) {
 182                 /**
 183                  * Set the error position is next to the last arg + space.
 184                  * Note that len includes the terminal null and the cursor
 185                  * appears at pos + 1.
 186                  */
 187                 pos = len;
 188                 offset = 0;
 189         }
 190
 191         /* And make a command string from argv array */
 192         p = command;
 193         for (i = 0; i < trace_probe_log.argc; i++) {
 194                 len = strlen(trace_probe_log.argv[i]);
 195                 strcpy(p, trace_probe_log.argv[i]);
 196                 p[len] = ' ';
 197                 p += len + 1;
 198         }
 199         *(p - 1) = '\0';
 200
 201         tracing_log_err(NULL, trace_probe_log.subsystem, command,
 202                         trace_probe_err_text, err_type, pos + offset);
 203
 204         kfree(command);
 205 }
 206
 207 /* Split symbol and offset. */
 208 int traceprobe_split_symbol_offset(char *symbol, long *offset)
 209 {
 210         char *tmp;
 211         int ret;
 212
 213         if (!offset)
 214                 return -EINVAL;
 215
 216         tmp = strpbrk(symbol, "+-");
 217         if (tmp) {
 218                 ret = kstrtol(tmp, 0, offset);
 219                 if (ret)
 220                         return ret;
 221                 *tmp = '\0';
 222         } else
 223                 *offset = 0;
 224
 225         return 0;
 226 }
 227
 228 /* @buf must has MAX_EVENT_NAME_LEN size */
 229 int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 230                                 char *buf, int offset)
 231 {
 232         const char *slash, *event = *pevent;
 233         int len;
 234
 235         slash = strchr(event, '/');
 236         if (!slash)
 237                 slash = strchr(event, '.');
 238
 239         if (slash) {
 240                 if (slash == event) {
 241                         trace_probe_log_err(offset, NO_GROUP_NAME);
 242                         return -EINVAL;
 243                 }
 244                 if (slash - event + 1 > MAX_EVENT_NAME_LEN) {
 245                         trace_probe_log_err(offset, GROUP_TOO_LONG);
 246                         return -EINVAL;
 247                 }
 248                 strlcpy(buf, event, slash - event + 1);
 249                 if (!is_good_name(buf)) {
 250                         trace_probe_log_err(offset, BAD_GROUP_NAME);
 251                         return -EINVAL;
 252                 }
 253                 *pgroup = buf;
 254                 *pevent = slash + 1;
 255                 offset += slash - event + 1;
 256                 event = *pevent;
 257         }
 258         len = strlen(event);
 259         if (len == 0) {
 260                 trace_probe_log_err(offset, NO_EVENT_NAME);
 261                 return -EINVAL;
 262         } else if (len > MAX_EVENT_NAME_LEN) {
 263                 trace_probe_log_err(offset, EVENT_TOO_LONG);
 264                 return -EINVAL;
 265         }
 266         if (!is_good_name(event)) {
 267                 trace_probe_log_err(offset, BAD_EVENT_NAME);
 268                 return -EINVAL;
 269         }
 270         return 0;
 271 }
 272
 273 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))
 274
 275 static int parse_probe_vars(char *arg, const struct fetch_type *t,
 276                         struct fetch_insn *code, unsigned int flags, int offs)
 277 {
 278         unsigned long param;
 279         int ret = 0;
 280         int len;
 281
 282         if (strcmp(arg, "retval") == 0) {
 283                 if (flags & TPARG_FL_RETURN) {
 284                         code->op = FETCH_OP_RETVAL;
 285                 } else {
 286                         trace_probe_log_err(offs, RETVAL_ON_PROBE);
 287                         ret = -EINVAL;
 288                 }
 289         } else if ((len = str_has_prefix(arg, "stack"))) {
 290                 if (arg[len] == '\0') {
 291                         code->op = FETCH_OP_STACKP;
 292                 } else if (isdigit(arg[len])) {
 293                         ret = kstrtoul(arg + len, 10, &param);
 294                         if (ret) {
 295                                 goto inval_var;
 296                         } else if ((flags & TPARG_FL_KERNEL) &&
 297                                     param > PARAM_MAX_STACK) {
 298                                 trace_probe_log_err(offs, BAD_STACK_NUM);
 299                                 ret = -EINVAL;
 300                         } else {
 301                                 code->op = FETCH_OP_STACK;
 302                                 code->param = (unsigned int)param;
 303                         }
 304                 } else
 305                         goto inval_var;
 306         } else if (strcmp(arg, "comm") == 0) {
 307                 code->op = FETCH_OP_COMM;
 308 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
 309         } else if (((flags & TPARG_FL_MASK) ==
 310                     (TPARG_FL_KERNEL | TPARG_FL_FENTRY)) &&
 311                    (len = str_has_prefix(arg, "arg"))) {
 312                 ret = kstrtoul(arg + len, 10, &param);
 313                 if (ret) {
 314                         goto inval_var;
 315                 } else if (!param || param > PARAM_MAX_STACK) {
 316                         trace_probe_log_err(offs, BAD_ARG_NUM);
 317                         return -EINVAL;
 318                 }
 319                 code->op = FETCH_OP_ARG;
 320                 code->param = (unsigned int)param - 1;
 321 #endif
 322         } else
 323                 goto inval_var;
 324
 325         return ret;
 326
 327 inval_var:
 328         trace_probe_log_err(offs, BAD_VAR);
 329         return -EINVAL;
 330 }
 331
 332 static int str_to_immediate(char *str, unsigned long *imm)
 333 {
 334         if (isdigit(str[0]))
 335                 return kstrtoul(str, 0, imm);
 336         else if (str[0] == '-')
 337                 return kstrtol(str, 0, (long *)imm);
 338         else if (str[0] == '+')
 339                 return kstrtol(str + 1, 0, (long *)imm);
 340         return -EINVAL;
 341 }
 342
 343 static int __parse_imm_string(char *str, char **pbuf, int offs)
 344 {
 345         size_t len = strlen(str);
 346
 347         if (str[len - 1] != '"') {
 348                 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE);
 349                 return -EINVAL;
 350         }
 351         *pbuf = kstrndup(str, len - 1, GFP_KERNEL);
 352         return 0;
 353 }
 354
 355 /* Recursive argument parser */
 356 static int
 357 parse_probe_arg(char *arg, const struct fetch_type *type,
 358                 struct fetch_insn **pcode, struct fetch_insn *end,
 359                 unsigned int flags, int offs)
 360 {
 361         struct fetch_insn *code = *pcode;
 362         unsigned long param;
 363         int deref = FETCH_OP_DEREF;
 364         long offset = 0;
 365         char *tmp;
 366         int ret = 0;
 367
 368         switch (arg[0]) {
 369         case '$':
 370                 ret = parse_probe_vars(arg + 1, type, code, flags, offs);
 371                 break;
 372
 373         case '%':       /* named register */
 374                 ret = regs_query_register_offset(arg + 1);
 375                 if (ret >= 0) {
 376                         code->op = FETCH_OP_REG;
 377                         code->param = (unsigned int)ret;
 378                         ret = 0;
 379                 } else
 380                         trace_probe_log_err(offs, BAD_REG_NAME);
 381                 break;
 382
 383         case '@':       /* memory, file-offset or symbol */
 384                 if (isdigit(arg[1])) {
 385                         ret = kstrtoul(arg + 1, 0, &param);
 386                         if (ret) {
 387                                 trace_probe_log_err(offs, BAD_MEM_ADDR);
 388                                 break;
 389                         }
 390                         /* load address */
 391                         code->op = FETCH_OP_IMM;
 392                         code->immediate = param;
 393                 } else if (arg[1] == '+') {
 394                         /* kprobes don't support file offsets */
 395                         if (flags & TPARG_FL_KERNEL) {
 396                                 trace_probe_log_err(offs, FILE_ON_KPROBE);
 397                                 return -EINVAL;
 398                         }
 399                         ret = kstrtol(arg + 2, 0, &offset);
 400                         if (ret) {
 401                                 trace_probe_log_err(offs, BAD_FILE_OFFS);
 402                                 break;
 403                         }
 404
 405                         code->op = FETCH_OP_FOFFS;
 406                         code->immediate = (unsigned long)offset;  // imm64?
 407                 } else {
 408                         /* uprobes don't support symbols */
 409                         if (!(flags & TPARG_FL_KERNEL)) {
 410                                 trace_probe_log_err(offs, SYM_ON_UPROBE);
 411                                 return -EINVAL;
 412                         }
 413                         /* Preserve symbol for updating */
 414                         code->op = FETCH_NOP_SYMBOL;
 415                         code->data = kstrdup(arg + 1, GFP_KERNEL);
 416                         if (!code->data)
 417                                 return -ENOMEM;
 418                         if (++code == end) {
 419                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 420                                 return -EINVAL;
 421                         }
 422                         code->op = FETCH_OP_IMM;
 423                         code->immediate = 0;
 424                 }
 425                 /* These are fetching from memory */
 426                 if (++code == end) {
 427                         trace_probe_log_err(offs, TOO_MANY_OPS);
 428                         return -EINVAL;
 429                 }
 430                 *pcode = code;
 431                 code->op = FETCH_OP_DEREF;
 432                 code->offset = offset;
 433                 break;
 434
 435         case '+':       /* deref memory */
 436         case '-':
 437                 if (arg[1] == 'u') {
 438                         deref = FETCH_OP_UDEREF;
 439                         arg[1] = arg[0];
 440                         arg++;
 441                 }
 442                 if (arg[0] == '+')
 443                         arg++;  /* Skip '+', because kstrtol() rejects it. */
 444                 tmp = strchr(arg, '(');
 445                 if (!tmp) {
 446                         trace_probe_log_err(offs, DEREF_NEED_BRACE);
 447                         return -EINVAL;
 448                 }
 449                 *tmp = '\0';
 450                 ret = kstrtol(arg, 0, &offset);
 451                 if (ret) {
 452                         trace_probe_log_err(offs, BAD_DEREF_OFFS);
 453                         break;
 454                 }
 455                 offs += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0);
 456                 arg = tmp + 1;
 457                 tmp = strrchr(arg, ')');
 458                 if (!tmp) {
 459                         trace_probe_log_err(offs + strlen(arg),
 460                                             DEREF_OPEN_BRACE);
 461                         return -EINVAL;
 462                 } else {
 463                         const struct fetch_type *t2 = find_fetch_type(NULL);
 464
 465                         *tmp = '\0';
 466                         ret = parse_probe_arg(arg, t2, &code, end, flags, offs);
 467                         if (ret)
 468                                 break;
 469                         if (code->op == FETCH_OP_COMM ||
 470                             code->op == FETCH_OP_DATA) {
 471                                 trace_probe_log_err(offs, COMM_CANT_DEREF);
 472                                 return -EINVAL;
 473                         }
 474                         if (++code == end) {
 475                                 trace_probe_log_err(offs, TOO_MANY_OPS);
 476                                 return -EINVAL;
 477                         }
 478                         *pcode = code;
 479
 480                         code->op = deref;
 481                         code->offset = offset;
 482                 }
 483                 break;
 484         case '\\':      /* Immediate value */
 485                 if (arg[1] == '"') {    /* Immediate string */
 486                         ret = __parse_imm_string(arg + 2, &tmp, offs + 2);
 487                         if (ret)
 488                                 break;
 489                         code->op = FETCH_OP_DATA;
 490                         code->data = tmp;
 491                 } else {
 492                         ret = str_to_immediate(arg + 1, &code->immediate);
 493                         if (ret)
 494                                 trace_probe_log_err(offs + 1, BAD_IMM);
 495                         else
 496                                 code->op = FETCH_OP_IMM;
 497                 }
 498                 break;
 499         }
 500         if (!ret && code->op == FETCH_OP_NOP) {
 501                 /* Parsed, but do not find fetch method */
 502                 trace_probe_log_err(offs, BAD_FETCH_ARG);
 503                 ret = -EINVAL;
 504         }
 505         return ret;
 506 }
 507
 508 #define BYTES_TO_BITS(nb)       ((BITS_PER_LONG * (nb)) / sizeof(long))
 509
 510 /* Bitfield type needs to be parsed into a fetch function */
 511 static int __parse_bitfield_probe_arg(const char *bf,
 512                                       const struct fetch_type *t,
 513                                       struct fetch_insn **pcode)
 514 {
 515         struct fetch_insn *code = *pcode;
 516         unsigned long bw, bo;
 517         char *tail;
 518
 519         if (*bf != 'b')
 520                 return 0;
 521
 522         bw = simple_strtoul(bf + 1, &tail, 0);  /* Use simple one */
 523
 524         if (bw == 0 || *tail != '@')
 525                 return -EINVAL;
 526
 527         bf = tail + 1;
 528         bo = simple_strtoul(bf, &tail, 0);
 529
 530         if (tail == bf || *tail != '/')
 531                 return -EINVAL;
 532         code++;
 533         if (code->op != FETCH_OP_NOP)
 534                 return -EINVAL;
 535         *pcode = code;
 536
 537         code->op = FETCH_OP_MOD_BF;
 538         code->lshift = BYTES_TO_BITS(t->size) - (bw + bo);
 539         code->rshift = BYTES_TO_BITS(t->size) - bw;
 540         code->basesize = t->size;
 541
 542         return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0;
 543 }
 544
 545 /* String length checking wrapper */
 546 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size,
 547                 struct probe_arg *parg, unsigned int flags, int offset)
 548 {
 549         struct fetch_insn *code, *scode, *tmp = NULL;
 550         char *t, *t2, *t3;
 551         char *arg;
 552         int ret, len;
 553
 554         arg = kstrdup(argv, GFP_KERNEL);
 555         if (!arg)
 556                 return -ENOMEM;
 557
 558         ret = -EINVAL;
 559         len = strlen(arg);
 560         if (len > MAX_ARGSTR_LEN) {
 561                 trace_probe_log_err(offset, ARG_TOO_LONG);
 562                 goto out;
 563         } else if (len == 0) {
 564                 trace_probe_log_err(offset, NO_ARG_BODY);
 565                 goto out;
 566         }
 567
 568         ret = -ENOMEM;
 569         parg->comm = kstrdup(arg, GFP_KERNEL);
 570         if (!parg->comm)
 571                 goto out;
 572
 573         ret = -EINVAL;
 574         t = strchr(arg, ':');
 575         if (t) {
 576                 *t = '\0';
 577                 t2 = strchr(++t, '[');
 578                 if (t2) {
 579                         *t2++ = '\0';
 580                         t3 = strchr(t2, ']');
 581                         if (!t3) {
 582                                 offset += t2 + strlen(t2) - arg;
 583                                 trace_probe_log_err(offset,
 584                                                     ARRAY_NO_CLOSE);
 585                                 goto out;
 586                         } else if (t3[1] != '\0') {
 587                                 trace_probe_log_err(offset + t3 + 1 - arg,
 588                                                     BAD_ARRAY_SUFFIX);
 589                                 goto out;
 590                         }
 591                         *t3 = '\0';
 592                         if (kstrtouint(t2, 0, &parg->count) || !parg->count) {
 593                                 trace_probe_log_err(offset + t2 - arg,
 594                                                     BAD_ARRAY_NUM);
 595                                 goto out;
 596                         }
 597                         if (parg->count > MAX_ARRAY_LEN) {
 598                                 trace_probe_log_err(offset + t2 - arg,
 599                                                     ARRAY_TOO_BIG);
 600                                 goto out;
 601                         }
 602                 }
 603         }
 604
 605         /*
 606          * Since $comm and immediate string can not be dereferenced,
 607          * we can find those by strcmp.
 608          */
 609         if (strcmp(arg, "$comm") == 0 || strncmp(arg, "\\\"", 2) == 0) {
 610                 /* The type of $comm must be "string", and not an array. */
 611                 if (parg->count || (t && strcmp(t, "string")))
 612                         goto out;
 613                 parg->type = find_fetch_type("string");
 614         } else
 615                 parg->type = find_fetch_type(t);
 616         if (!parg->type) {
 617                 trace_probe_log_err(offset + (t ? (t - arg) : 0), BAD_TYPE);
 618                 goto out;
 619         }
 620         parg->offset = *size;
 621         *size += parg->type->size * (parg->count ?: 1);
 622
 623         ret = -ENOMEM;
 624         if (parg->count) {
 625                 len = strlen(parg->type->fmttype) + 6;
 626                 parg->fmt = kmalloc(len, GFP_KERNEL);
 627                 if (!parg->fmt)
 628                         goto out;
 629                 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype,
 630                          parg->count);
 631         }
 632
 633         code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL);
 634         if (!code)
 635                 goto out;
 636         code[FETCH_INSN_MAX - 1].op = FETCH_OP_END;
 637
 638         ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1],
 639                               flags, offset);
 640         if (ret)
 641                 goto fail;
 642
 643         ret = -EINVAL;
 644         /* Store operation */
 645         if (!strcmp(parg->type->name, "string") ||
 646             !strcmp(parg->type->name, "ustring")) {
 647                 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF &&
 648                     code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM &&
 649                     code->op != FETCH_OP_DATA) {
 650                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 651                                             BAD_STRING);
 652                         goto fail;
 653                 }
 654                 if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM ||
 655                      code->op == FETCH_OP_DATA) || parg->count) {
 656                         /*
 657                          * IMM, DATA and COMM is pointing actual address, those
 658                          * must be kept, and if parg->count != 0, this is an
 659                          * array of string pointers instead of string address
 660                          * itself.
 661                          */
 662                         code++;
 663                         if (code->op != FETCH_OP_NOP) {
 664                                 trace_probe_log_err(offset, TOO_MANY_OPS);
 665                                 goto fail;
 666                         }
 667                 }
 668                 /* If op == DEREF, replace it with STRING */
 669                 if (!strcmp(parg->type->name, "ustring") ||
 670                     code->op == FETCH_OP_UDEREF)
 671                         code->op = FETCH_OP_ST_USTRING;
 672                 else
 673                         code->op = FETCH_OP_ST_STRING;
 674                 code->size = parg->type->size;
 675                 parg->dynamic = true;
 676         } else if (code->op == FETCH_OP_DEREF) {
 677                 code->op = FETCH_OP_ST_MEM;
 678                 code->size = parg->type->size;
 679         } else if (code->op == FETCH_OP_UDEREF) {
 680                 code->op = FETCH_OP_ST_UMEM;
 681                 code->size = parg->type->size;
 682         } else {
 683                 code++;
 684                 if (code->op != FETCH_OP_NOP) {
 685                         trace_probe_log_err(offset, TOO_MANY_OPS);
 686                         goto fail;
 687                 }
 688                 code->op = FETCH_OP_ST_RAW;
 689                 code->size = parg->type->size;
 690         }
 691         scode = code;
 692         /* Modify operation */
 693         if (t != NULL) {
 694                 ret = __parse_bitfield_probe_arg(t, parg->type, &code);
 695                 if (ret) {
 696                         trace_probe_log_err(offset + t - arg, BAD_BITFIELD);
 697                         goto fail;
 698                 }
 699         }
 700         ret = -EINVAL;
 701         /* Loop(Array) operation */
 702         if (parg->count) {
 703                 if (scode->op != FETCH_OP_ST_MEM &&
 704                     scode->op != FETCH_OP_ST_STRING &&
 705                     scode->op != FETCH_OP_ST_USTRING) {
 706                         trace_probe_log_err(offset + (t ? (t - arg) : 0),
 707                                             BAD_STRING);
 708                         goto fail;
 709                 }
 710                 code++;
 711                 if (code->op != FETCH_OP_NOP) {
 712                         trace_probe_log_err(offset, TOO_MANY_OPS);
 713                         goto fail;
 714                 }
 715                 code->op = FETCH_OP_LP_ARRAY;
 716                 code->param = parg->count;
 717         }
 718         code++;
 719         code->op = FETCH_OP_END;
 720
 721         ret = 0;
 722         /* Shrink down the code buffer */
 723         parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL);
 724         if (!parg->code)
 725                 ret = -ENOMEM;
 726         else
 727                 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1));
 728
 729 fail:
 730         if (ret) {
 731                 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++)
 732                         if (code->op == FETCH_NOP_SYMBOL ||
 733                             code->op == FETCH_OP_DATA)
 734                                 kfree(code->data);
 735         }
 736         kfree(tmp);
 737 out:
 738         kfree(arg);
 739
 740         return ret;
 741 }
 742
 743 /* Return 1 if name is reserved or already used by another argument */
 744 static int traceprobe_conflict_field_name(const char *name,
 745                                           struct probe_arg *args, int narg)
 746 {
 747         int i;
 748
 749         for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++)
 750                 if (strcmp(reserved_field_names[i], name) == 0)
 751                         return 1;
 752
 753         for (i = 0; i < narg; i++)
 754                 if (strcmp(args[i].name, name) == 0)
 755                         return 1;
 756
 757         return 0;
 758 }
 759
 760 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg,
 761                                 unsigned int flags)
 762 {
 763         struct probe_arg *parg = &tp->args[i];
 764         const char *body;
 765
 766         /* Increment count for freeing args in error case */
 767         tp->nr_args++;
 768
 769         body = strchr(arg, '=');
 770         if (body) {
 771                 if (body - arg > MAX_ARG_NAME_LEN) {
 772                         trace_probe_log_err(0, ARG_NAME_TOO_LONG);
 773                         return -EINVAL;
 774                 } else if (body == arg) {
 775                         trace_probe_log_err(0, NO_ARG_NAME);
 776                         return -EINVAL;
 777                 }
 778                 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL);
 779                 body++;
 780         } else {
 781                 /* If argument name is omitted, set "argN" */
 782                 parg->name = kasprintf(GFP_KERNEL, "arg%d", i + 1);
 783                 body = arg;
 784         }
 785         if (!parg->name)
 786                 return -ENOMEM;
 787
 788         if (!is_good_name(parg->name)) {
 789                 trace_probe_log_err(0, BAD_ARG_NAME);
 790                 return -EINVAL;
 791         }
 792         if (traceprobe_conflict_field_name(parg->name, tp->args, i)) {
 793                 trace_probe_log_err(0, USED_ARG_NAME);
 794                 return -EINVAL;
 795         }
 796         /* Parse fetch argument */
 797         return traceprobe_parse_probe_arg_body(body, &tp->size, parg, flags,
 798                                                body - arg);
 799 }
 800
 801 void traceprobe_free_probe_arg(struct probe_arg *arg)
 802 {
 803         struct fetch_insn *code = arg->code;
 804
 805         while (code && code->op != FETCH_OP_END) {
 806                 if (code->op == FETCH_NOP_SYMBOL ||
 807                     code->op == FETCH_OP_DATA)
 808                         kfree(code->data);
 809                 code++;
 810         }
 811         kfree(arg->code);
 812         kfree(arg->name);
 813         kfree(arg->comm);
 814         kfree(arg->fmt);
 815 }
 816
 817 int traceprobe_update_arg(struct probe_arg *arg)
 818 {
 819         struct fetch_insn *code = arg->code;
 820         long offset;
 821         char *tmp;
 822         char c;
 823         int ret = 0;
 824
 825         while (code && code->op != FETCH_OP_END) {
 826                 if (code->op == FETCH_NOP_SYMBOL) {
 827                         if (code[1].op != FETCH_OP_IMM)
 828                                 return -EINVAL;
 829
 830                         tmp = strpbrk(code->data, "+-");
 831                         if (tmp)
 832                                 c = *tmp;
 833                         ret = traceprobe_split_symbol_offset(code->data,
 834                                                              &offset);
 835                         if (ret)
 836                                 return ret;
 837
 838                         code[1].immediate =
 839                                 (unsigned long)kallsyms_lookup_name(code->data);
 840                         if (tmp)
 841                                 *tmp = c;
 842                         if (!code[1].immediate)
 843                                 return -ENOENT;
 844                         code[1].immediate += offset;
 845                 }
 846                 code++;
 847         }
 848         return 0;
 849 }
 850
 851 /* When len=0, we just calculate the needed length */
 852 #define LEN_OR_ZERO (len ? len - pos : 0)
 853 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len,
 854                            enum probe_print_type ptype)
 855 {
 856         struct probe_arg *parg;
 857         int i, j;
 858         int pos = 0;
 859         const char *fmt, *arg;
 860
 861         switch (ptype) {
 862         case PROBE_PRINT_NORMAL:
 863                 fmt = "(%lx)";
 864                 arg = "REC->" FIELD_STRING_IP;
 865                 break;
 866         case PROBE_PRINT_RETURN:
 867                 fmt = "(%lx <- %lx)";
 868                 arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
 869                 break;
 870         default:
 871                 WARN_ON_ONCE(1);
 872                 return 0;
 873         }
 874
 875         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
 876
 877         for (i = 0; i < tp->nr_args; i++) {
 878                 parg = tp->args + i;
 879                 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name);
 880                 if (parg->count) {
 881                         pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s",
 882                                         parg->type->fmt);
 883                         for (j = 1; j < parg->count; j++)
 884                                 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s",
 885                                                 parg->type->fmt);
 886                         pos += snprintf(buf + pos, LEN_OR_ZERO, "}");
 887                 } else
 888                         pos += snprintf(buf + pos, LEN_OR_ZERO, "%s",
 889                                         parg->type->fmt);
 890         }
 891
 892         pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
 893
 894         for (i = 0; i < tp->nr_args; i++) {
 895                 parg = tp->args + i;
 896                 if (parg->count) {
 897                         if ((strcmp(parg->type->name, "string") == 0) ||
 898                             (strcmp(parg->type->name, "ustring") == 0))
 899                                 fmt = ", __get_str(%s[%d])";
 900                         else
 901                                 fmt = ", REC->%s[%d]";
 902                         for (j = 0; j < parg->count; j++)
 903                                 pos += snprintf(buf + pos, LEN_OR_ZERO,
 904                                                 fmt, parg->name, j);
 905                 } else {
 906                         if ((strcmp(parg->type->name, "string") == 0) ||
 907                             (strcmp(parg->type->name, "ustring") == 0))
 908                                 fmt = ", __get_str(%s)";
 909                         else
 910                                 fmt = ", REC->%s";
 911                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 912                                         fmt, parg->name);
 913                 }
 914         }
 915
 916         /* return the length of print_fmt */
 917         return pos;
 918 }
 919 #undef LEN_OR_ZERO
 920
 921 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype)
 922 {
 923         struct trace_event_call *call = trace_probe_event_call(tp);
 924         int len;
 925         char *print_fmt;
 926
 927         /* First: called with 0 length to calculate the needed length */
 928         len = __set_print_fmt(tp, NULL, 0, ptype);
 929         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 930         if (!print_fmt)
 931                 return -ENOMEM;
 932
 933         /* Second: actually write the @print_fmt */
 934         __set_print_fmt(tp, print_fmt, len + 1, ptype);
 935         call->print_fmt = print_fmt;
 936
 937         return 0;
 938 }
 939
 940 int traceprobe_define_arg_fields(struct trace_event_call *event_call,
 941                                  size_t offset, struct trace_probe *tp)
 942 {
 943         int ret, i;
 944
 945         /* Set argument names as fields */
 946         for (i = 0; i < tp->nr_args; i++) {
 947                 struct probe_arg *parg = &tp->args[i];
 948                 const char *fmt = parg->type->fmttype;
 949                 int size = parg->type->size;
 950
 951                 if (parg->fmt)
 952                         fmt = parg->fmt;
 953                 if (parg->count)
 954                         size *= parg->count;
 955                 ret = trace_define_field(event_call, fmt, parg->name,
 956                                          offset + parg->offset, size,
 957                                          parg->type->is_signed,
 958                                          FILTER_OTHER);
 959                 if (ret)
 960                         return ret;
 961         }
 962         return 0;
 963 }
 964
 965 static void trace_probe_event_free(struct trace_probe_event *tpe)
 966 {
 967         kfree(tpe->class.system);
 968         kfree(tpe->call.name);
 969         kfree(tpe->call.print_fmt);
 970         kfree(tpe);
 971 }
 972
 973 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
 974 {
 975         if (trace_probe_has_sibling(tp))
 976                 return -EBUSY;
 977
 978         list_del_init(&tp->list);
 979         trace_probe_event_free(tp->event);
 980
 981         tp->event = to->event;
 982         list_add_tail(&tp->list, trace_probe_probe_list(to));
 983
 984         return 0;
 985 }
 986
 987 void trace_probe_unlink(struct trace_probe *tp)
 988 {
 989         list_del_init(&tp->list);
 990         if (list_empty(trace_probe_probe_list(tp)))
 991                 trace_probe_event_free(tp->event);
 992         tp->event = NULL;
 993 }
 994
 995 void trace_probe_cleanup(struct trace_probe *tp)
 996 {
 997         int i;
 998
 999         for (i = 0; i < tp->nr_args; i++)
1000                 traceprobe_free_probe_arg(&tp->args[i]);
1001
1002         if (tp->event)
1003                 trace_probe_unlink(tp);
1004 }
1005
1006 int trace_probe_init(struct trace_probe *tp, const char *event,
1007                      const char *group, bool alloc_filter)
1008 {
1009         struct trace_event_call *call;
1010         size_t size = sizeof(struct trace_probe_event);
1011         int ret = 0;
1012
1013         if (!event || !group)
1014                 return -EINVAL;
1015
1016         if (alloc_filter)
1017                 size += sizeof(struct trace_uprobe_filter);
1018
1019         tp->event = kzalloc(size, GFP_KERNEL);
1020         if (!tp->event)
1021                 return -ENOMEM;
1022
1023         INIT_LIST_HEAD(&tp->event->files);
1024         INIT_LIST_HEAD(&tp->event->class.fields);
1025         INIT_LIST_HEAD(&tp->event->probes);
1026         INIT_LIST_HEAD(&tp->list);
1027         list_add(&tp->list, &tp->event->probes);
1028
1029         call = trace_probe_event_call(tp);
1030         call->class = &tp->event->class;
1031         call->name = kstrdup(event, GFP_KERNEL);
1032         if (!call->name) {
1033                 ret = -ENOMEM;
1034                 goto error;
1035         }
1036
1037         tp->event->class.system = kstrdup(group, GFP_KERNEL);
1038         if (!tp->event->class.system) {
1039                 ret = -ENOMEM;
1040                 goto error;
1041         }
1042
1043         return 0;
1044
1045 error:
1046         trace_probe_cleanup(tp);
1047         return ret;
1048 }
1049
1050 int trace_probe_register_event_call(struct trace_probe *tp)
1051 {
1052         struct trace_event_call *call = trace_probe_event_call(tp);
1053         int ret;
1054
1055         ret = register_trace_event(&call->event);
1056         if (!ret)
1057                 return -ENODEV;
1058
1059         ret = trace_add_event_call(call);
1060         if (ret)
1061                 unregister_trace_event(&call->event);
1062
1063         return ret;
1064 }
1065
1066 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file)
1067 {
1068         struct event_file_link *link;
1069
1070         link = kmalloc(sizeof(*link), GFP_KERNEL);
1071         if (!link)
1072                 return -ENOMEM;
1073
1074         link->file = file;
1075         INIT_LIST_HEAD(&link->list);
1076         list_add_tail_rcu(&link->list, &tp->event->files);
1077         trace_probe_set_flag(tp, TP_FLAG_TRACE);
1078         return 0;
1079 }
1080
1081 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
1082                                                   struct trace_event_file *file)
1083 {
1084         struct event_file_link *link;
1085
1086         trace_probe_for_each_link(link, tp) {
1087                 if (link->file == file)
1088                         return link;
1089         }
1090
1091         return NULL;
1092 }
1093
1094 int trace_probe_remove_file(struct trace_probe *tp,
1095                             struct trace_event_file *file)
1096 {
1097         struct event_file_link *link;
1098
1099         link = trace_probe_get_file_link(tp, file);
1100         if (!link)
1101                 return -ENOENT;
1102
1103         list_del_rcu(&link->list);
1104         synchronize_rcu();
1105         kfree(link);
1106
1107         if (list_empty(&tp->event->files))
1108                 trace_probe_clear_flag(tp, TP_FLAG_TRACE);
1109
1110         return 0;
1111 }
1112
1113 /*
1114  * Return the smallest index of different type argument (start from 1).
1115  * If all argument types and name are same, return 0.
1116  */
1117 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
1118 {
1119         int i;
1120
1121         /* In case of more arguments */
1122         if (a->nr_args < b->nr_args)
1123                 return a->nr_args + 1;
1124         if (a->nr_args > b->nr_args)
1125                 return b->nr_args + 1;
1126
1127         for (i = 0; i < a->nr_args; i++) {
1128                 if ((b->nr_args <= i) ||
1129                     ((a->args[i].type != b->args[i].type) ||
1130                      (a->args[i].count != b->args[i].count) ||
1131                      strcmp(a->args[i].name, b->args[i].name)))
1132                         return i + 1;
1133         }
1134
1135         return 0;
1136 }
1137
1138 bool trace_probe_match_command_args(struct trace_probe *tp,
1139                                     int argc, const char **argv)
1140 {
1141         char buf[MAX_ARGSTR_LEN + 1];
1142         int i;
1143
1144         if (tp->nr_args < argc)
1145                 return false;
1146
1147         for (i = 0; i < argc; i++) {
1148                 snprintf(buf, sizeof(buf), "%s=%s",
1149                          tp->args[i].name, tp->args[i].comm);
1150                 if (strcmp(buf, argv[i]))
1151                         return false;
1152         }
1153         return true;
1154 }
1155
1156 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **))
1157 {
1158         int argc = 0, ret = 0;
1159         char **argv;
1160
1161         argv = argv_split(GFP_KERNEL, raw_command, &argc);
1162         if (!argv)
1163                 return -ENOMEM;
1164
1165         if (argc)
1166                 ret = createfn(argc, (const char **)argv);
1167
1168         argv_free(argv);
1169
1170         return ret;
1171 }