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 <[email protected]> 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 <linux/bpf.h> 15 #include "trace_btf.h" 16 17 #include "trace_probe.h" 18 19 #undef C 20 #define C(a, b) b 21 22 static const char *trace_probe_err_text[] = { ERRORS }; 23 24 static const char *reserved_field_names[] = { 25 "common_type", 26 "common_flags", 27 "common_preempt_count", 28 "common_pid", 29 "common_tgid", 30 FIELD_STRING_IP, 31 FIELD_STRING_RETIP, 32 FIELD_STRING_FUNC, 33 }; 34 35 /* Printing in basic type function template */ 36 #define DEFINE_BASIC_PRINT_TYPE_FUNC(tname, type, fmt) \ 37 int PRINT_TYPE_FUNC_NAME(tname)(struct trace_seq *s, void *data, void *ent)\ 38 { \ 39 trace_seq_printf(s, fmt, *(type *)data); \ 40 return !trace_seq_has_overflowed(s); \ 41 } \ 42 const char PRINT_TYPE_FMT_NAME(tname)[] = fmt; 43 44 DEFINE_BASIC_PRINT_TYPE_FUNC(u8, u8, "%u") 45 DEFINE_BASIC_PRINT_TYPE_FUNC(u16, u16, "%u") 46 DEFINE_BASIC_PRINT_TYPE_FUNC(u32, u32, "%u") 47 DEFINE_BASIC_PRINT_TYPE_FUNC(u64, u64, "%Lu") 48 DEFINE_BASIC_PRINT_TYPE_FUNC(s8, s8, "%d") 49 DEFINE_BASIC_PRINT_TYPE_FUNC(s16, s16, "%d") 50 DEFINE_BASIC_PRINT_TYPE_FUNC(s32, s32, "%d") 51 DEFINE_BASIC_PRINT_TYPE_FUNC(s64, s64, "%Ld") 52 DEFINE_BASIC_PRINT_TYPE_FUNC(x8, u8, "0x%x") 53 DEFINE_BASIC_PRINT_TYPE_FUNC(x16, u16, "0x%x") 54 DEFINE_BASIC_PRINT_TYPE_FUNC(x32, u32, "0x%x") 55 DEFINE_BASIC_PRINT_TYPE_FUNC(x64, u64, "0x%Lx") 56 DEFINE_BASIC_PRINT_TYPE_FUNC(char, u8, "'%c'") 57 58 int PRINT_TYPE_FUNC_NAME(symbol)(struct trace_seq *s, void *data, void *ent) 59 { 60 trace_seq_printf(s, "%pS", (void *)*(unsigned long *)data); 61 return !trace_seq_has_overflowed(s); 62 } 63 const char PRINT_TYPE_FMT_NAME(symbol)[] = "%pS"; 64 65 /* Print type function for string type */ 66 int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent) 67 { 68 int len = *(u32 *)data >> 16; 69 70 if (!len) 71 trace_seq_puts(s, FAULT_STRING); 72 else 73 trace_seq_printf(s, "\"%s\"", 74 (const char *)get_loc_data(data, ent)); 75 return !trace_seq_has_overflowed(s); 76 } 77 78 const char PRINT_TYPE_FMT_NAME(string)[] = "\\\"%s\\\""; 79 80 /* Fetch type information table */ 81 static const struct fetch_type probe_fetch_types[] = { 82 /* Special types */ 83 __ASSIGN_FETCH_TYPE("string", string, string, sizeof(u32), 1, 1, 84 "__data_loc char[]"), 85 __ASSIGN_FETCH_TYPE("ustring", string, string, sizeof(u32), 1, 1, 86 "__data_loc char[]"), 87 __ASSIGN_FETCH_TYPE("symstr", string, string, sizeof(u32), 1, 1, 88 "__data_loc char[]"), 89 /* Basic types */ 90 ASSIGN_FETCH_TYPE(u8, u8, 0), 91 ASSIGN_FETCH_TYPE(u16, u16, 0), 92 ASSIGN_FETCH_TYPE(u32, u32, 0), 93 ASSIGN_FETCH_TYPE(u64, u64, 0), 94 ASSIGN_FETCH_TYPE(s8, u8, 1), 95 ASSIGN_FETCH_TYPE(s16, u16, 1), 96 ASSIGN_FETCH_TYPE(s32, u32, 1), 97 ASSIGN_FETCH_TYPE(s64, u64, 1), 98 ASSIGN_FETCH_TYPE_ALIAS(x8, u8, u8, 0), 99 ASSIGN_FETCH_TYPE_ALIAS(x16, u16, u16, 0), 100 ASSIGN_FETCH_TYPE_ALIAS(x32, u32, u32, 0), 101 ASSIGN_FETCH_TYPE_ALIAS(x64, u64, u64, 0), 102 ASSIGN_FETCH_TYPE_ALIAS(char, u8, u8, 0), 103 ASSIGN_FETCH_TYPE_ALIAS(symbol, ADDR_FETCH_TYPE, ADDR_FETCH_TYPE, 0), 104 105 ASSIGN_FETCH_TYPE_END 106 }; 107 108 static const struct fetch_type *find_fetch_type(const char *type, unsigned long flags) 109 { 110 int i; 111 112 /* Reject the symbol/symstr for uprobes */ 113 if (type && (flags & TPARG_FL_USER) && 114 (!strcmp(type, "symbol") || !strcmp(type, "symstr"))) 115 return NULL; 116 117 if (!type) 118 type = DEFAULT_FETCH_TYPE_STR; 119 120 /* Special case: bitfield */ 121 if (*type == 'b') { 122 unsigned long bs; 123 124 type = strchr(type, '/'); 125 if (!type) 126 goto fail; 127 128 type++; 129 if (kstrtoul(type, 0, &bs)) 130 goto fail; 131 132 switch (bs) { 133 case 8: 134 return find_fetch_type("u8", flags); 135 case 16: 136 return find_fetch_type("u16", flags); 137 case 32: 138 return find_fetch_type("u32", flags); 139 case 64: 140 return find_fetch_type("u64", flags); 141 default: 142 goto fail; 143 } 144 } 145 146 for (i = 0; probe_fetch_types[i].name; i++) { 147 if (strcmp(type, probe_fetch_types[i].name) == 0) 148 return &probe_fetch_types[i]; 149 } 150 151 fail: 152 return NULL; 153 } 154 155 static struct trace_probe_log trace_probe_log; 156 157 void trace_probe_log_init(const char *subsystem, int argc, const char **argv) 158 { 159 trace_probe_log.subsystem = subsystem; 160 trace_probe_log.argc = argc; 161 trace_probe_log.argv = argv; 162 trace_probe_log.index = 0; 163 } 164 165 void trace_probe_log_clear(void) 166 { 167 memset(&trace_probe_log, 0, sizeof(trace_probe_log)); 168 } 169 170 void trace_probe_log_set_index(int index) 171 { 172 trace_probe_log.index = index; 173 } 174 175 void __trace_probe_log_err(int offset, int err_type) 176 { 177 char *command, *p; 178 int i, len = 0, pos = 0; 179 180 if (!trace_probe_log.argv) 181 return; 182 183 /* Recalculate the length and allocate buffer */ 184 for (i = 0; i < trace_probe_log.argc; i++) { 185 if (i == trace_probe_log.index) 186 pos = len; 187 len += strlen(trace_probe_log.argv[i]) + 1; 188 } 189 command = kzalloc(len, GFP_KERNEL); 190 if (!command) 191 return; 192 193 if (trace_probe_log.index >= trace_probe_log.argc) { 194 /** 195 * Set the error position is next to the last arg + space. 196 * Note that len includes the terminal null and the cursor 197 * appears at pos + 1. 198 */ 199 pos = len; 200 offset = 0; 201 } 202 203 /* And make a command string from argv array */ 204 p = command; 205 for (i = 0; i < trace_probe_log.argc; i++) { 206 len = strlen(trace_probe_log.argv[i]); 207 strcpy(p, trace_probe_log.argv[i]); 208 p[len] = ' '; 209 p += len + 1; 210 } 211 *(p - 1) = '\0'; 212 213 tracing_log_err(NULL, trace_probe_log.subsystem, command, 214 trace_probe_err_text, err_type, pos + offset); 215 216 kfree(command); 217 } 218 219 /* Split symbol and offset. */ 220 int traceprobe_split_symbol_offset(char *symbol, long *offset) 221 { 222 char *tmp; 223 int ret; 224 225 if (!offset) 226 return -EINVAL; 227 228 tmp = strpbrk(symbol, "+-"); 229 if (tmp) { 230 ret = kstrtol(tmp, 0, offset); 231 if (ret) 232 return ret; 233 *tmp = '\0'; 234 } else 235 *offset = 0; 236 237 return 0; 238 } 239 240 /* @buf must has MAX_EVENT_NAME_LEN size */ 241 int traceprobe_parse_event_name(const char **pevent, const char **pgroup, 242 char *buf, int offset) 243 { 244 const char *slash, *event = *pevent; 245 int len; 246 247 slash = strchr(event, '/'); 248 if (!slash) 249 slash = strchr(event, '.'); 250 251 if (slash) { 252 if (slash == event) { 253 trace_probe_log_err(offset, NO_GROUP_NAME); 254 return -EINVAL; 255 } 256 if (slash - event + 1 > MAX_EVENT_NAME_LEN) { 257 trace_probe_log_err(offset, GROUP_TOO_LONG); 258 return -EINVAL; 259 } 260 strscpy(buf, event, slash - event + 1); 261 if (!is_good_system_name(buf)) { 262 trace_probe_log_err(offset, BAD_GROUP_NAME); 263 return -EINVAL; 264 } 265 *pgroup = buf; 266 *pevent = slash + 1; 267 offset += slash - event + 1; 268 event = *pevent; 269 } 270 len = strlen(event); 271 if (len == 0) { 272 if (slash) { 273 *pevent = NULL; 274 return 0; 275 } 276 trace_probe_log_err(offset, NO_EVENT_NAME); 277 return -EINVAL; 278 } else if (len > MAX_EVENT_NAME_LEN) { 279 trace_probe_log_err(offset, EVENT_TOO_LONG); 280 return -EINVAL; 281 } 282 if (!is_good_name(event)) { 283 trace_probe_log_err(offset, BAD_EVENT_NAME); 284 return -EINVAL; 285 } 286 return 0; 287 } 288 289 static int parse_trace_event_arg(char *arg, struct fetch_insn *code, 290 struct traceprobe_parse_context *ctx) 291 { 292 struct ftrace_event_field *field; 293 struct list_head *head; 294 295 head = trace_get_fields(ctx->event); 296 list_for_each_entry(field, head, link) { 297 if (!strcmp(arg, field->name)) { 298 code->op = FETCH_OP_TP_ARG; 299 code->data = field; 300 return 0; 301 } 302 } 303 return -ENOENT; 304 } 305 306 #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS 307 308 static u32 btf_type_int(const struct btf_type *t) 309 { 310 return *(u32 *)(t + 1); 311 } 312 313 static bool btf_type_is_char_ptr(struct btf *btf, const struct btf_type *type) 314 { 315 const struct btf_type *real_type; 316 u32 intdata; 317 s32 tid; 318 319 real_type = btf_type_skip_modifiers(btf, type->type, &tid); 320 if (!real_type) 321 return false; 322 323 if (BTF_INFO_KIND(real_type->info) != BTF_KIND_INT) 324 return false; 325 326 intdata = btf_type_int(real_type); 327 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) 328 && BTF_INT_BITS(intdata) == 8; 329 } 330 331 static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type) 332 { 333 const struct btf_type *real_type; 334 const struct btf_array *array; 335 u32 intdata; 336 s32 tid; 337 338 if (BTF_INFO_KIND(type->info) != BTF_KIND_ARRAY) 339 return false; 340 341 array = (const struct btf_array *)(type + 1); 342 343 real_type = btf_type_skip_modifiers(btf, array->type, &tid); 344 345 intdata = btf_type_int(real_type); 346 return !(BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) 347 && BTF_INT_BITS(intdata) == 8; 348 } 349 350 static int check_prepare_btf_string_fetch(char *typename, 351 struct fetch_insn **pcode, 352 struct traceprobe_parse_context *ctx) 353 { 354 struct btf *btf = ctx->btf; 355 356 if (!btf || !ctx->last_type) 357 return 0; 358 359 /* char [] does not need any change. */ 360 if (btf_type_is_char_array(btf, ctx->last_type)) 361 return 0; 362 363 /* char * requires dereference the pointer. */ 364 if (btf_type_is_char_ptr(btf, ctx->last_type)) { 365 struct fetch_insn *code = *pcode + 1; 366 367 if (code->op == FETCH_OP_END) { 368 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 369 return -E2BIG; 370 } 371 if (typename[0] == 'u') 372 code->op = FETCH_OP_UDEREF; 373 else 374 code->op = FETCH_OP_DEREF; 375 code->offset = 0; 376 *pcode = code; 377 return 0; 378 } 379 /* Other types are not available for string */ 380 trace_probe_log_err(ctx->offset, BAD_TYPE4STR); 381 return -EINVAL; 382 } 383 384 static const char *fetch_type_from_btf_type(struct btf *btf, 385 const struct btf_type *type, 386 struct traceprobe_parse_context *ctx) 387 { 388 u32 intdata; 389 390 /* TODO: const char * could be converted as a string */ 391 switch (BTF_INFO_KIND(type->info)) { 392 case BTF_KIND_ENUM: 393 /* enum is "int", so convert to "s32" */ 394 return "s32"; 395 case BTF_KIND_ENUM64: 396 return "s64"; 397 case BTF_KIND_PTR: 398 /* pointer will be converted to "x??" */ 399 if (IS_ENABLED(CONFIG_64BIT)) 400 return "x64"; 401 else 402 return "x32"; 403 case BTF_KIND_INT: 404 intdata = btf_type_int(type); 405 if (BTF_INT_ENCODING(intdata) & BTF_INT_SIGNED) { 406 switch (BTF_INT_BITS(intdata)) { 407 case 8: 408 return "s8"; 409 case 16: 410 return "s16"; 411 case 32: 412 return "s32"; 413 case 64: 414 return "s64"; 415 } 416 } else { /* unsigned */ 417 switch (BTF_INT_BITS(intdata)) { 418 case 8: 419 return "u8"; 420 case 16: 421 return "u16"; 422 case 32: 423 return "u32"; 424 case 64: 425 return "u64"; 426 } 427 /* bitfield, size is encoded in the type */ 428 ctx->last_bitsize = BTF_INT_BITS(intdata); 429 ctx->last_bitoffs += BTF_INT_OFFSET(intdata); 430 return "u64"; 431 } 432 } 433 /* TODO: support other types */ 434 435 return NULL; 436 } 437 438 static int query_btf_context(struct traceprobe_parse_context *ctx) 439 { 440 const struct btf_param *param; 441 const struct btf_type *type; 442 struct btf *btf; 443 s32 nr; 444 445 if (ctx->btf) 446 return 0; 447 448 if (!ctx->funcname) 449 return -EINVAL; 450 451 type = btf_find_func_proto(ctx->funcname, &btf); 452 if (!type) 453 return -ENOENT; 454 455 ctx->btf = btf; 456 ctx->proto = type; 457 458 /* ctx->params is optional, since func(void) will not have params. */ 459 nr = 0; 460 param = btf_get_func_param(type, &nr); 461 if (!IS_ERR_OR_NULL(param)) { 462 /* Hide the first 'data' argument of tracepoint */ 463 if (ctx->flags & TPARG_FL_TPOINT) { 464 nr--; 465 param++; 466 } 467 } 468 469 if (nr > 0) { 470 ctx->nr_params = nr; 471 ctx->params = param; 472 } else { 473 ctx->nr_params = 0; 474 ctx->params = NULL; 475 } 476 477 return 0; 478 } 479 480 static void clear_btf_context(struct traceprobe_parse_context *ctx) 481 { 482 if (ctx->btf) { 483 btf_put(ctx->btf); 484 ctx->btf = NULL; 485 ctx->proto = NULL; 486 ctx->params = NULL; 487 ctx->nr_params = 0; 488 } 489 } 490 491 /* Return 1 if the field separater is arrow operator ('->') */ 492 static int split_next_field(char *varname, char **next_field, 493 struct traceprobe_parse_context *ctx) 494 { 495 char *field; 496 int ret = 0; 497 498 field = strpbrk(varname, ".-"); 499 if (field) { 500 if (field[0] == '-' && field[1] == '>') { 501 field[0] = '\0'; 502 field += 2; 503 ret = 1; 504 } else if (field[0] == '.') { 505 field[0] = '\0'; 506 field += 1; 507 } else { 508 trace_probe_log_err(ctx->offset + field - varname, BAD_HYPHEN); 509 return -EINVAL; 510 } 511 *next_field = field; 512 } 513 514 return ret; 515 } 516 517 /* 518 * Parse the field of data structure. The @type must be a pointer type 519 * pointing the target data structure type. 520 */ 521 static int parse_btf_field(char *fieldname, const struct btf_type *type, 522 struct fetch_insn **pcode, struct fetch_insn *end, 523 struct traceprobe_parse_context *ctx) 524 { 525 struct fetch_insn *code = *pcode; 526 const struct btf_member *field; 527 u32 bitoffs, anon_offs; 528 char *next; 529 int is_ptr; 530 s32 tid; 531 532 do { 533 /* Outer loop for solving arrow operator ('->') */ 534 if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) { 535 trace_probe_log_err(ctx->offset, NO_PTR_STRCT); 536 return -EINVAL; 537 } 538 /* Convert a struct pointer type to a struct type */ 539 type = btf_type_skip_modifiers(ctx->btf, type->type, &tid); 540 if (!type) { 541 trace_probe_log_err(ctx->offset, BAD_BTF_TID); 542 return -EINVAL; 543 } 544 545 bitoffs = 0; 546 do { 547 /* Inner loop for solving dot operator ('.') */ 548 next = NULL; 549 is_ptr = split_next_field(fieldname, &next, ctx); 550 if (is_ptr < 0) 551 return is_ptr; 552 553 anon_offs = 0; 554 field = btf_find_struct_member(ctx->btf, type, fieldname, 555 &anon_offs); 556 if (!field) { 557 trace_probe_log_err(ctx->offset, NO_BTF_FIELD); 558 return -ENOENT; 559 } 560 /* Add anonymous structure/union offset */ 561 bitoffs += anon_offs; 562 563 /* Accumulate the bit-offsets of the dot-connected fields */ 564 if (btf_type_kflag(type)) { 565 bitoffs += BTF_MEMBER_BIT_OFFSET(field->offset); 566 ctx->last_bitsize = BTF_MEMBER_BITFIELD_SIZE(field->offset); 567 } else { 568 bitoffs += field->offset; 569 ctx->last_bitsize = 0; 570 } 571 572 type = btf_type_skip_modifiers(ctx->btf, field->type, &tid); 573 if (!type) { 574 trace_probe_log_err(ctx->offset, BAD_BTF_TID); 575 return -EINVAL; 576 } 577 578 ctx->offset += next - fieldname; 579 fieldname = next; 580 } while (!is_ptr && fieldname); 581 582 if (++code == end) { 583 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 584 return -EINVAL; 585 } 586 code->op = FETCH_OP_DEREF; /* TODO: user deref support */ 587 code->offset = bitoffs / 8; 588 *pcode = code; 589 590 ctx->last_bitoffs = bitoffs % 8; 591 ctx->last_type = type; 592 } while (fieldname); 593 594 return 0; 595 } 596 597 static int parse_btf_arg(char *varname, 598 struct fetch_insn **pcode, struct fetch_insn *end, 599 struct traceprobe_parse_context *ctx) 600 { 601 struct fetch_insn *code = *pcode; 602 const struct btf_param *params; 603 const struct btf_type *type; 604 char *field = NULL; 605 int i, is_ptr, ret; 606 u32 tid; 607 608 if (WARN_ON_ONCE(!ctx->funcname)) 609 return -EINVAL; 610 611 is_ptr = split_next_field(varname, &field, ctx); 612 if (is_ptr < 0) 613 return is_ptr; 614 if (!is_ptr && field) { 615 /* dot-connected field on an argument is not supported. */ 616 trace_probe_log_err(ctx->offset + field - varname, 617 NOSUP_DAT_ARG); 618 return -EOPNOTSUPP; 619 } 620 621 if (ctx->flags & TPARG_FL_RETURN) { 622 if (strcmp(varname, "$retval") != 0) { 623 trace_probe_log_err(ctx->offset, NO_BTFARG); 624 return -ENOENT; 625 } 626 code->op = FETCH_OP_RETVAL; 627 /* Check whether the function return type is not void */ 628 if (query_btf_context(ctx) == 0) { 629 if (ctx->proto->type == 0) { 630 trace_probe_log_err(ctx->offset, NO_RETVAL); 631 return -ENOENT; 632 } 633 tid = ctx->proto->type; 634 goto found; 635 } 636 if (field) { 637 trace_probe_log_err(ctx->offset + field - varname, 638 NO_BTF_ENTRY); 639 return -ENOENT; 640 } 641 return 0; 642 } 643 644 if (!ctx->btf) { 645 ret = query_btf_context(ctx); 646 if (ret < 0 || ctx->nr_params == 0) { 647 trace_probe_log_err(ctx->offset, NO_BTF_ENTRY); 648 return PTR_ERR(params); 649 } 650 } 651 params = ctx->params; 652 653 for (i = 0; i < ctx->nr_params; i++) { 654 const char *name = btf_name_by_offset(ctx->btf, params[i].name_off); 655 656 if (name && !strcmp(name, varname)) { 657 code->op = FETCH_OP_ARG; 658 if (ctx->flags & TPARG_FL_TPOINT) 659 code->param = i + 1; 660 else 661 code->param = i; 662 tid = params[i].type; 663 goto found; 664 } 665 } 666 trace_probe_log_err(ctx->offset, NO_BTFARG); 667 return -ENOENT; 668 669 found: 670 type = btf_type_skip_modifiers(ctx->btf, tid, &tid); 671 if (!type) { 672 trace_probe_log_err(ctx->offset, BAD_BTF_TID); 673 return -EINVAL; 674 } 675 /* Initialize the last type information */ 676 ctx->last_type = type; 677 ctx->last_bitoffs = 0; 678 ctx->last_bitsize = 0; 679 if (field) { 680 ctx->offset += field - varname; 681 return parse_btf_field(field, type, pcode, end, ctx); 682 } 683 return 0; 684 } 685 686 static const struct fetch_type *find_fetch_type_from_btf_type( 687 struct traceprobe_parse_context *ctx) 688 { 689 struct btf *btf = ctx->btf; 690 const char *typestr = NULL; 691 692 if (btf && ctx->last_type) 693 typestr = fetch_type_from_btf_type(btf, ctx->last_type, ctx); 694 695 return find_fetch_type(typestr, ctx->flags); 696 } 697 698 static int parse_btf_bitfield(struct fetch_insn **pcode, 699 struct traceprobe_parse_context *ctx) 700 { 701 struct fetch_insn *code = *pcode; 702 703 if ((ctx->last_bitsize % 8 == 0) && ctx->last_bitoffs == 0) 704 return 0; 705 706 code++; 707 if (code->op != FETCH_OP_NOP) { 708 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 709 return -EINVAL; 710 } 711 *pcode = code; 712 713 code->op = FETCH_OP_MOD_BF; 714 code->lshift = 64 - (ctx->last_bitsize + ctx->last_bitoffs); 715 code->rshift = 64 - ctx->last_bitsize; 716 code->basesize = 64 / 8; 717 return 0; 718 } 719 720 #else 721 static void clear_btf_context(struct traceprobe_parse_context *ctx) 722 { 723 ctx->btf = NULL; 724 } 725 726 static int query_btf_context(struct traceprobe_parse_context *ctx) 727 { 728 return -EOPNOTSUPP; 729 } 730 731 static int parse_btf_arg(char *varname, 732 struct fetch_insn **pcode, struct fetch_insn *end, 733 struct traceprobe_parse_context *ctx) 734 { 735 trace_probe_log_err(ctx->offset, NOSUP_BTFARG); 736 return -EOPNOTSUPP; 737 } 738 739 static int parse_btf_bitfield(struct fetch_insn **pcode, 740 struct traceprobe_parse_context *ctx) 741 { 742 trace_probe_log_err(ctx->offset, NOSUP_BTFARG); 743 return -EOPNOTSUPP; 744 } 745 746 #define find_fetch_type_from_btf_type(ctx) \ 747 find_fetch_type(NULL, ctx->flags) 748 749 static int check_prepare_btf_string_fetch(char *typename, 750 struct fetch_insn **pcode, 751 struct traceprobe_parse_context *ctx) 752 { 753 return 0; 754 } 755 756 #endif 757 758 #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long)) 759 760 /* Parse $vars. @orig_arg points '$', which syncs to @ctx->offset */ 761 static int parse_probe_vars(char *orig_arg, const struct fetch_type *t, 762 struct fetch_insn **pcode, 763 struct fetch_insn *end, 764 struct traceprobe_parse_context *ctx) 765 { 766 struct fetch_insn *code = *pcode; 767 int err = TP_ERR_BAD_VAR; 768 char *arg = orig_arg + 1; 769 unsigned long param; 770 int ret = 0; 771 int len; 772 773 if (ctx->flags & TPARG_FL_TEVENT) { 774 if (code->data) 775 return -EFAULT; 776 ret = parse_trace_event_arg(arg, code, ctx); 777 if (!ret) 778 return 0; 779 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { 780 code->op = FETCH_OP_COMM; 781 return 0; 782 } 783 /* backward compatibility */ 784 ctx->offset = 0; 785 goto inval; 786 } 787 788 if (str_has_prefix(arg, "retval")) { 789 if (!(ctx->flags & TPARG_FL_RETURN)) { 790 err = TP_ERR_RETVAL_ON_PROBE; 791 goto inval; 792 } 793 if (!(ctx->flags & TPARG_FL_KERNEL) || 794 !IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) { 795 code->op = FETCH_OP_RETVAL; 796 return 0; 797 } 798 return parse_btf_arg(orig_arg, pcode, end, ctx); 799 } 800 801 len = str_has_prefix(arg, "stack"); 802 if (len) { 803 804 if (arg[len] == '\0') { 805 code->op = FETCH_OP_STACKP; 806 return 0; 807 } 808 809 if (isdigit(arg[len])) { 810 ret = kstrtoul(arg + len, 10, ¶m); 811 if (ret) 812 goto inval; 813 814 if ((ctx->flags & TPARG_FL_KERNEL) && 815 param > PARAM_MAX_STACK) { 816 err = TP_ERR_BAD_STACK_NUM; 817 goto inval; 818 } 819 code->op = FETCH_OP_STACK; 820 code->param = (unsigned int)param; 821 return 0; 822 } 823 goto inval; 824 } 825 826 if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) { 827 code->op = FETCH_OP_COMM; 828 return 0; 829 } 830 831 #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API 832 len = str_has_prefix(arg, "arg"); 833 if (len && tparg_is_function_entry(ctx->flags)) { 834 ret = kstrtoul(arg + len, 10, ¶m); 835 if (ret) 836 goto inval; 837 838 if (!param || param > PARAM_MAX_STACK) { 839 err = TP_ERR_BAD_ARG_NUM; 840 goto inval; 841 } 842 843 code->op = FETCH_OP_ARG; 844 code->param = (unsigned int)param - 1; 845 /* 846 * The tracepoint probe will probe a stub function, and the 847 * first parameter of the stub is a dummy and should be ignored. 848 */ 849 if (ctx->flags & TPARG_FL_TPOINT) 850 code->param++; 851 return 0; 852 } 853 #endif 854 855 inval: 856 __trace_probe_log_err(ctx->offset, err); 857 return -EINVAL; 858 } 859 860 static int str_to_immediate(char *str, unsigned long *imm) 861 { 862 if (isdigit(str[0])) 863 return kstrtoul(str, 0, imm); 864 else if (str[0] == '-') 865 return kstrtol(str, 0, (long *)imm); 866 else if (str[0] == '+') 867 return kstrtol(str + 1, 0, (long *)imm); 868 return -EINVAL; 869 } 870 871 static int __parse_imm_string(char *str, char **pbuf, int offs) 872 { 873 size_t len = strlen(str); 874 875 if (str[len - 1] != '"') { 876 trace_probe_log_err(offs + len, IMMSTR_NO_CLOSE); 877 return -EINVAL; 878 } 879 *pbuf = kstrndup(str, len - 1, GFP_KERNEL); 880 if (!*pbuf) 881 return -ENOMEM; 882 return 0; 883 } 884 885 /* Recursive argument parser */ 886 static int 887 parse_probe_arg(char *arg, const struct fetch_type *type, 888 struct fetch_insn **pcode, struct fetch_insn *end, 889 struct traceprobe_parse_context *ctx) 890 { 891 struct fetch_insn *code = *pcode; 892 unsigned long param; 893 int deref = FETCH_OP_DEREF; 894 long offset = 0; 895 char *tmp; 896 int ret = 0; 897 898 switch (arg[0]) { 899 case '$': 900 ret = parse_probe_vars(arg, type, pcode, end, ctx); 901 break; 902 903 case '%': /* named register */ 904 if (ctx->flags & (TPARG_FL_TEVENT | TPARG_FL_FPROBE)) { 905 /* eprobe and fprobe do not handle registers */ 906 trace_probe_log_err(ctx->offset, BAD_VAR); 907 break; 908 } 909 ret = regs_query_register_offset(arg + 1); 910 if (ret >= 0) { 911 code->op = FETCH_OP_REG; 912 code->param = (unsigned int)ret; 913 ret = 0; 914 } else 915 trace_probe_log_err(ctx->offset, BAD_REG_NAME); 916 break; 917 918 case '@': /* memory, file-offset or symbol */ 919 if (isdigit(arg[1])) { 920 ret = kstrtoul(arg + 1, 0, ¶m); 921 if (ret) { 922 trace_probe_log_err(ctx->offset, BAD_MEM_ADDR); 923 break; 924 } 925 /* load address */ 926 code->op = FETCH_OP_IMM; 927 code->immediate = param; 928 } else if (arg[1] == '+') { 929 /* kprobes don't support file offsets */ 930 if (ctx->flags & TPARG_FL_KERNEL) { 931 trace_probe_log_err(ctx->offset, FILE_ON_KPROBE); 932 return -EINVAL; 933 } 934 ret = kstrtol(arg + 2, 0, &offset); 935 if (ret) { 936 trace_probe_log_err(ctx->offset, BAD_FILE_OFFS); 937 break; 938 } 939 940 code->op = FETCH_OP_FOFFS; 941 code->immediate = (unsigned long)offset; // imm64? 942 } else { 943 /* uprobes don't support symbols */ 944 if (!(ctx->flags & TPARG_FL_KERNEL)) { 945 trace_probe_log_err(ctx->offset, SYM_ON_UPROBE); 946 return -EINVAL; 947 } 948 /* Preserve symbol for updating */ 949 code->op = FETCH_NOP_SYMBOL; 950 code->data = kstrdup(arg + 1, GFP_KERNEL); 951 if (!code->data) 952 return -ENOMEM; 953 if (++code == end) { 954 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 955 return -EINVAL; 956 } 957 code->op = FETCH_OP_IMM; 958 code->immediate = 0; 959 } 960 /* These are fetching from memory */ 961 if (++code == end) { 962 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 963 return -EINVAL; 964 } 965 *pcode = code; 966 code->op = FETCH_OP_DEREF; 967 code->offset = offset; 968 break; 969 970 case '+': /* deref memory */ 971 case '-': 972 if (arg[1] == 'u') { 973 deref = FETCH_OP_UDEREF; 974 arg[1] = arg[0]; 975 arg++; 976 } 977 if (arg[0] == '+') 978 arg++; /* Skip '+', because kstrtol() rejects it. */ 979 tmp = strchr(arg, '('); 980 if (!tmp) { 981 trace_probe_log_err(ctx->offset, DEREF_NEED_BRACE); 982 return -EINVAL; 983 } 984 *tmp = '\0'; 985 ret = kstrtol(arg, 0, &offset); 986 if (ret) { 987 trace_probe_log_err(ctx->offset, BAD_DEREF_OFFS); 988 break; 989 } 990 ctx->offset += (tmp + 1 - arg) + (arg[0] != '-' ? 1 : 0); 991 arg = tmp + 1; 992 tmp = strrchr(arg, ')'); 993 if (!tmp) { 994 trace_probe_log_err(ctx->offset + strlen(arg), 995 DEREF_OPEN_BRACE); 996 return -EINVAL; 997 } else { 998 const struct fetch_type *t2 = find_fetch_type(NULL, ctx->flags); 999 int cur_offs = ctx->offset; 1000 1001 *tmp = '\0'; 1002 ret = parse_probe_arg(arg, t2, &code, end, ctx); 1003 if (ret) 1004 break; 1005 ctx->offset = cur_offs; 1006 if (code->op == FETCH_OP_COMM || 1007 code->op == FETCH_OP_DATA) { 1008 trace_probe_log_err(ctx->offset, COMM_CANT_DEREF); 1009 return -EINVAL; 1010 } 1011 if (++code == end) { 1012 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1013 return -EINVAL; 1014 } 1015 *pcode = code; 1016 1017 code->op = deref; 1018 code->offset = offset; 1019 /* Reset the last type if used */ 1020 ctx->last_type = NULL; 1021 } 1022 break; 1023 case '\\': /* Immediate value */ 1024 if (arg[1] == '"') { /* Immediate string */ 1025 ret = __parse_imm_string(arg + 2, &tmp, ctx->offset + 2); 1026 if (ret) 1027 break; 1028 code->op = FETCH_OP_DATA; 1029 code->data = tmp; 1030 } else { 1031 ret = str_to_immediate(arg + 1, &code->immediate); 1032 if (ret) 1033 trace_probe_log_err(ctx->offset + 1, BAD_IMM); 1034 else 1035 code->op = FETCH_OP_IMM; 1036 } 1037 break; 1038 default: 1039 if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */ 1040 if (!tparg_is_function_entry(ctx->flags)) { 1041 trace_probe_log_err(ctx->offset, NOSUP_BTFARG); 1042 return -EINVAL; 1043 } 1044 ret = parse_btf_arg(arg, pcode, end, ctx); 1045 break; 1046 } 1047 } 1048 if (!ret && code->op == FETCH_OP_NOP) { 1049 /* Parsed, but do not find fetch method */ 1050 trace_probe_log_err(ctx->offset, BAD_FETCH_ARG); 1051 ret = -EINVAL; 1052 } 1053 return ret; 1054 } 1055 1056 #define BYTES_TO_BITS(nb) ((BITS_PER_LONG * (nb)) / sizeof(long)) 1057 1058 /* Bitfield type needs to be parsed into a fetch function */ 1059 static int __parse_bitfield_probe_arg(const char *bf, 1060 const struct fetch_type *t, 1061 struct fetch_insn **pcode) 1062 { 1063 struct fetch_insn *code = *pcode; 1064 unsigned long bw, bo; 1065 char *tail; 1066 1067 if (*bf != 'b') 1068 return 0; 1069 1070 bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */ 1071 1072 if (bw == 0 || *tail != '@') 1073 return -EINVAL; 1074 1075 bf = tail + 1; 1076 bo = simple_strtoul(bf, &tail, 0); 1077 1078 if (tail == bf || *tail != '/') 1079 return -EINVAL; 1080 code++; 1081 if (code->op != FETCH_OP_NOP) 1082 return -EINVAL; 1083 *pcode = code; 1084 1085 code->op = FETCH_OP_MOD_BF; 1086 code->lshift = BYTES_TO_BITS(t->size) - (bw + bo); 1087 code->rshift = BYTES_TO_BITS(t->size) - bw; 1088 code->basesize = t->size; 1089 1090 return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; 1091 } 1092 1093 /* Split type part from @arg and return it. */ 1094 static char *parse_probe_arg_type(char *arg, struct probe_arg *parg, 1095 struct traceprobe_parse_context *ctx) 1096 { 1097 char *t = NULL, *t2, *t3; 1098 int offs; 1099 1100 t = strchr(arg, ':'); 1101 if (t) { 1102 *t++ = '\0'; 1103 t2 = strchr(t, '['); 1104 if (t2) { 1105 *t2++ = '\0'; 1106 t3 = strchr(t2, ']'); 1107 if (!t3) { 1108 offs = t2 + strlen(t2) - arg; 1109 1110 trace_probe_log_err(ctx->offset + offs, 1111 ARRAY_NO_CLOSE); 1112 return ERR_PTR(-EINVAL); 1113 } else if (t3[1] != '\0') { 1114 trace_probe_log_err(ctx->offset + t3 + 1 - arg, 1115 BAD_ARRAY_SUFFIX); 1116 return ERR_PTR(-EINVAL); 1117 } 1118 *t3 = '\0'; 1119 if (kstrtouint(t2, 0, &parg->count) || !parg->count) { 1120 trace_probe_log_err(ctx->offset + t2 - arg, 1121 BAD_ARRAY_NUM); 1122 return ERR_PTR(-EINVAL); 1123 } 1124 if (parg->count > MAX_ARRAY_LEN) { 1125 trace_probe_log_err(ctx->offset + t2 - arg, 1126 ARRAY_TOO_BIG); 1127 return ERR_PTR(-EINVAL); 1128 } 1129 } 1130 } 1131 offs = t ? t - arg : 0; 1132 1133 /* 1134 * Since $comm and immediate string can not be dereferenced, 1135 * we can find those by strcmp. But ignore for eprobes. 1136 */ 1137 if (!(ctx->flags & TPARG_FL_TEVENT) && 1138 (strcmp(arg, "$comm") == 0 || strcmp(arg, "$COMM") == 0 || 1139 strncmp(arg, "\\\"", 2) == 0)) { 1140 /* The type of $comm must be "string", and not an array type. */ 1141 if (parg->count || (t && strcmp(t, "string"))) { 1142 trace_probe_log_err(ctx->offset + offs, NEED_STRING_TYPE); 1143 return ERR_PTR(-EINVAL); 1144 } 1145 parg->type = find_fetch_type("string", ctx->flags); 1146 } else 1147 parg->type = find_fetch_type(t, ctx->flags); 1148 1149 if (!parg->type) { 1150 trace_probe_log_err(ctx->offset + offs, BAD_TYPE); 1151 return ERR_PTR(-EINVAL); 1152 } 1153 1154 return t; 1155 } 1156 1157 /* After parsing, adjust the fetch_insn according to the probe_arg */ 1158 static int finalize_fetch_insn(struct fetch_insn *code, 1159 struct probe_arg *parg, 1160 char *type, 1161 int type_offset, 1162 struct traceprobe_parse_context *ctx) 1163 { 1164 struct fetch_insn *scode; 1165 int ret; 1166 1167 /* Store operation */ 1168 if (parg->type->is_string) { 1169 /* Check bad combination of the type and the last fetch_insn. */ 1170 if (!strcmp(parg->type->name, "symstr")) { 1171 if (code->op != FETCH_OP_REG && code->op != FETCH_OP_STACK && 1172 code->op != FETCH_OP_RETVAL && code->op != FETCH_OP_ARG && 1173 code->op != FETCH_OP_DEREF && code->op != FETCH_OP_TP_ARG) { 1174 trace_probe_log_err(ctx->offset + type_offset, 1175 BAD_SYMSTRING); 1176 return -EINVAL; 1177 } 1178 } else { 1179 if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_UDEREF && 1180 code->op != FETCH_OP_IMM && code->op != FETCH_OP_COMM && 1181 code->op != FETCH_OP_DATA && code->op != FETCH_OP_TP_ARG) { 1182 trace_probe_log_err(ctx->offset + type_offset, 1183 BAD_STRING); 1184 return -EINVAL; 1185 } 1186 } 1187 1188 if (!strcmp(parg->type->name, "symstr") || 1189 (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM || 1190 code->op == FETCH_OP_DATA) || code->op == FETCH_OP_TP_ARG || 1191 parg->count) { 1192 /* 1193 * IMM, DATA and COMM is pointing actual address, those 1194 * must be kept, and if parg->count != 0, this is an 1195 * array of string pointers instead of string address 1196 * itself. 1197 * For the symstr, it doesn't need to dereference, thus 1198 * it just get the value. 1199 */ 1200 code++; 1201 if (code->op != FETCH_OP_NOP) { 1202 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1203 return -EINVAL; 1204 } 1205 } 1206 1207 /* If op == DEREF, replace it with STRING */ 1208 if (!strcmp(parg->type->name, "ustring") || 1209 code->op == FETCH_OP_UDEREF) 1210 code->op = FETCH_OP_ST_USTRING; 1211 else if (!strcmp(parg->type->name, "symstr")) 1212 code->op = FETCH_OP_ST_SYMSTR; 1213 else 1214 code->op = FETCH_OP_ST_STRING; 1215 code->size = parg->type->size; 1216 parg->dynamic = true; 1217 } else if (code->op == FETCH_OP_DEREF) { 1218 code->op = FETCH_OP_ST_MEM; 1219 code->size = parg->type->size; 1220 } else if (code->op == FETCH_OP_UDEREF) { 1221 code->op = FETCH_OP_ST_UMEM; 1222 code->size = parg->type->size; 1223 } else { 1224 code++; 1225 if (code->op != FETCH_OP_NOP) { 1226 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1227 return -E2BIG; 1228 } 1229 code->op = FETCH_OP_ST_RAW; 1230 code->size = parg->type->size; 1231 } 1232 1233 /* Save storing fetch_insn. */ 1234 scode = code; 1235 1236 /* Modify operation */ 1237 if (type != NULL) { 1238 /* Bitfield needs a special fetch_insn. */ 1239 ret = __parse_bitfield_probe_arg(type, parg->type, &code); 1240 if (ret) { 1241 trace_probe_log_err(ctx->offset + type_offset, BAD_BITFIELD); 1242 return ret; 1243 } 1244 } else if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && 1245 ctx->last_type) { 1246 /* If user not specified the type, try parsing BTF bitfield. */ 1247 ret = parse_btf_bitfield(&code, ctx); 1248 if (ret) 1249 return ret; 1250 } 1251 1252 /* Loop(Array) operation */ 1253 if (parg->count) { 1254 if (scode->op != FETCH_OP_ST_MEM && 1255 scode->op != FETCH_OP_ST_STRING && 1256 scode->op != FETCH_OP_ST_USTRING) { 1257 trace_probe_log_err(ctx->offset + type_offset, BAD_STRING); 1258 return -EINVAL; 1259 } 1260 code++; 1261 if (code->op != FETCH_OP_NOP) { 1262 trace_probe_log_err(ctx->offset, TOO_MANY_OPS); 1263 return -E2BIG; 1264 } 1265 code->op = FETCH_OP_LP_ARRAY; 1266 code->param = parg->count; 1267 } 1268 1269 /* Finalize the fetch_insn array. */ 1270 code++; 1271 code->op = FETCH_OP_END; 1272 1273 return 0; 1274 } 1275 1276 /* String length checking wrapper */ 1277 static int traceprobe_parse_probe_arg_body(const char *argv, ssize_t *size, 1278 struct probe_arg *parg, 1279 struct traceprobe_parse_context *ctx) 1280 { 1281 struct fetch_insn *code, *tmp = NULL; 1282 char *type, *arg; 1283 int ret, len; 1284 1285 len = strlen(argv); 1286 if (len > MAX_ARGSTR_LEN) { 1287 trace_probe_log_err(ctx->offset, ARG_TOO_LONG); 1288 return -E2BIG; 1289 } else if (len == 0) { 1290 trace_probe_log_err(ctx->offset, NO_ARG_BODY); 1291 return -EINVAL; 1292 } 1293 1294 arg = kstrdup(argv, GFP_KERNEL); 1295 if (!arg) 1296 return -ENOMEM; 1297 1298 parg->comm = kstrdup(arg, GFP_KERNEL); 1299 if (!parg->comm) { 1300 ret = -ENOMEM; 1301 goto out; 1302 } 1303 1304 type = parse_probe_arg_type(arg, parg, ctx); 1305 if (IS_ERR(type)) { 1306 ret = PTR_ERR(type); 1307 goto out; 1308 } 1309 1310 code = tmp = kcalloc(FETCH_INSN_MAX, sizeof(*code), GFP_KERNEL); 1311 if (!code) { 1312 ret = -ENOMEM; 1313 goto out; 1314 } 1315 code[FETCH_INSN_MAX - 1].op = FETCH_OP_END; 1316 1317 ctx->last_type = NULL; 1318 ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1], 1319 ctx); 1320 if (ret < 0) 1321 goto fail; 1322 1323 /* Update storing type if BTF is available */ 1324 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS) && 1325 ctx->last_type) { 1326 if (!type) { 1327 parg->type = find_fetch_type_from_btf_type(ctx); 1328 } else if (strstr(type, "string")) { 1329 ret = check_prepare_btf_string_fetch(type, &code, ctx); 1330 if (ret) 1331 goto fail; 1332 } 1333 } 1334 parg->offset = *size; 1335 *size += parg->type->size * (parg->count ?: 1); 1336 1337 if (parg->count) { 1338 len = strlen(parg->type->fmttype) + 6; 1339 parg->fmt = kmalloc(len, GFP_KERNEL); 1340 if (!parg->fmt) { 1341 ret = -ENOMEM; 1342 goto out; 1343 } 1344 snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, 1345 parg->count); 1346 } 1347 1348 ret = finalize_fetch_insn(code, parg, type, type ? type - arg : 0, ctx); 1349 if (ret < 0) 1350 goto fail; 1351 1352 for (; code < tmp + FETCH_INSN_MAX; code++) 1353 if (code->op == FETCH_OP_END) 1354 break; 1355 /* Shrink down the code buffer */ 1356 parg->code = kcalloc(code - tmp + 1, sizeof(*code), GFP_KERNEL); 1357 if (!parg->code) 1358 ret = -ENOMEM; 1359 else 1360 memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1)); 1361 1362 fail: 1363 if (ret < 0) { 1364 for (code = tmp; code < tmp + FETCH_INSN_MAX; code++) 1365 if (code->op == FETCH_NOP_SYMBOL || 1366 code->op == FETCH_OP_DATA) 1367 kfree(code->data); 1368 } 1369 kfree(tmp); 1370 out: 1371 kfree(arg); 1372 1373 return ret; 1374 } 1375 1376 /* Return 1 if name is reserved or already used by another argument */ 1377 static int traceprobe_conflict_field_name(const char *name, 1378 struct probe_arg *args, int narg) 1379 { 1380 int i; 1381 1382 for (i = 0; i < ARRAY_SIZE(reserved_field_names); i++) 1383 if (strcmp(reserved_field_names[i], name) == 0) 1384 return 1; 1385 1386 for (i = 0; i < narg; i++) 1387 if (strcmp(args[i].name, name) == 0) 1388 return 1; 1389 1390 return 0; 1391 } 1392 1393 static char *generate_probe_arg_name(const char *arg, int idx) 1394 { 1395 char *name = NULL; 1396 const char *end; 1397 1398 /* 1399 * If argument name is omitted, try arg as a name (BTF variable) 1400 * or "argN". 1401 */ 1402 if (IS_ENABLED(CONFIG_PROBE_EVENTS_BTF_ARGS)) { 1403 end = strchr(arg, ':'); 1404 if (!end) 1405 end = arg + strlen(arg); 1406 1407 name = kmemdup_nul(arg, end - arg, GFP_KERNEL); 1408 if (!name || !is_good_name(name)) { 1409 kfree(name); 1410 name = NULL; 1411 } 1412 } 1413 1414 if (!name) 1415 name = kasprintf(GFP_KERNEL, "arg%d", idx + 1); 1416 1417 return name; 1418 } 1419 1420 int traceprobe_parse_probe_arg(struct trace_probe *tp, int i, const char *arg, 1421 struct traceprobe_parse_context *ctx) 1422 { 1423 struct probe_arg *parg = &tp->args[i]; 1424 const char *body; 1425 1426 body = strchr(arg, '='); 1427 if (body) { 1428 if (body - arg > MAX_ARG_NAME_LEN) { 1429 trace_probe_log_err(0, ARG_NAME_TOO_LONG); 1430 return -EINVAL; 1431 } else if (body == arg) { 1432 trace_probe_log_err(0, NO_ARG_NAME); 1433 return -EINVAL; 1434 } 1435 parg->name = kmemdup_nul(arg, body - arg, GFP_KERNEL); 1436 body++; 1437 } else { 1438 parg->name = generate_probe_arg_name(arg, i); 1439 body = arg; 1440 } 1441 if (!parg->name) 1442 return -ENOMEM; 1443 1444 if (!is_good_name(parg->name)) { 1445 trace_probe_log_err(0, BAD_ARG_NAME); 1446 return -EINVAL; 1447 } 1448 if (traceprobe_conflict_field_name(parg->name, tp->args, i)) { 1449 trace_probe_log_err(0, USED_ARG_NAME); 1450 return -EINVAL; 1451 } 1452 ctx->offset = body - arg; 1453 /* Parse fetch argument */ 1454 return traceprobe_parse_probe_arg_body(body, &tp->size, parg, ctx); 1455 } 1456 1457 void traceprobe_free_probe_arg(struct probe_arg *arg) 1458 { 1459 struct fetch_insn *code = arg->code; 1460 1461 while (code && code->op != FETCH_OP_END) { 1462 if (code->op == FETCH_NOP_SYMBOL || 1463 code->op == FETCH_OP_DATA) 1464 kfree(code->data); 1465 code++; 1466 } 1467 kfree(arg->code); 1468 kfree(arg->name); 1469 kfree(arg->comm); 1470 kfree(arg->fmt); 1471 } 1472 1473 static int argv_has_var_arg(int argc, const char *argv[], int *args_idx, 1474 struct traceprobe_parse_context *ctx) 1475 { 1476 int i, found = 0; 1477 1478 for (i = 0; i < argc; i++) 1479 if (str_has_prefix(argv[i], "$arg")) { 1480 trace_probe_log_set_index(i + 2); 1481 1482 if (!tparg_is_function_entry(ctx->flags)) { 1483 trace_probe_log_err(0, NOFENTRY_ARGS); 1484 return -EINVAL; 1485 } 1486 1487 if (isdigit(argv[i][4])) { 1488 found = 1; 1489 continue; 1490 } 1491 1492 if (argv[i][4] != '*') { 1493 trace_probe_log_err(0, BAD_VAR); 1494 return -EINVAL; 1495 } 1496 1497 if (*args_idx >= 0 && *args_idx < argc) { 1498 trace_probe_log_err(0, DOUBLE_ARGS); 1499 return -EINVAL; 1500 } 1501 found = 1; 1502 *args_idx = i; 1503 } 1504 1505 return found; 1506 } 1507 1508 static int sprint_nth_btf_arg(int idx, const char *type, 1509 char *buf, int bufsize, 1510 struct traceprobe_parse_context *ctx) 1511 { 1512 const char *name; 1513 int ret; 1514 1515 if (idx >= ctx->nr_params) { 1516 trace_probe_log_err(0, NO_BTFARG); 1517 return -ENOENT; 1518 } 1519 name = btf_name_by_offset(ctx->btf, ctx->params[idx].name_off); 1520 if (!name) { 1521 trace_probe_log_err(0, NO_BTF_ENTRY); 1522 return -ENOENT; 1523 } 1524 ret = snprintf(buf, bufsize, "%s%s", name, type); 1525 if (ret >= bufsize) { 1526 trace_probe_log_err(0, ARGS_2LONG); 1527 return -E2BIG; 1528 } 1529 return ret; 1530 } 1531 1532 /* Return new_argv which must be freed after use */ 1533 const char **traceprobe_expand_meta_args(int argc, const char *argv[], 1534 int *new_argc, char *buf, int bufsize, 1535 struct traceprobe_parse_context *ctx) 1536 { 1537 const struct btf_param *params = NULL; 1538 int i, j, n, used, ret, args_idx = -1; 1539 const char **new_argv = NULL; 1540 1541 ret = argv_has_var_arg(argc, argv, &args_idx, ctx); 1542 if (ret < 0) 1543 return ERR_PTR(ret); 1544 1545 if (!ret) { 1546 *new_argc = argc; 1547 return NULL; 1548 } 1549 1550 ret = query_btf_context(ctx); 1551 if (ret < 0 || ctx->nr_params == 0) { 1552 if (args_idx != -1) { 1553 /* $arg* requires BTF info */ 1554 trace_probe_log_err(0, NOSUP_BTFARG); 1555 return (const char **)params; 1556 } 1557 *new_argc = argc; 1558 return NULL; 1559 } 1560 1561 if (args_idx >= 0) 1562 *new_argc = argc + ctx->nr_params - 1; 1563 else 1564 *new_argc = argc; 1565 1566 new_argv = kcalloc(*new_argc, sizeof(char *), GFP_KERNEL); 1567 if (!new_argv) 1568 return ERR_PTR(-ENOMEM); 1569 1570 used = 0; 1571 for (i = 0, j = 0; i < argc; i++) { 1572 trace_probe_log_set_index(i + 2); 1573 if (i == args_idx) { 1574 for (n = 0; n < ctx->nr_params; n++) { 1575 ret = sprint_nth_btf_arg(n, "", buf + used, 1576 bufsize - used, ctx); 1577 if (ret < 0) 1578 goto error; 1579 1580 new_argv[j++] = buf + used; 1581 used += ret + 1; 1582 } 1583 continue; 1584 } 1585 1586 if (str_has_prefix(argv[i], "$arg")) { 1587 char *type = NULL; 1588 1589 n = simple_strtoul(argv[i] + 4, &type, 10); 1590 if (type && !(*type == ':' || *type == '\0')) { 1591 trace_probe_log_err(0, BAD_VAR); 1592 ret = -ENOENT; 1593 goto error; 1594 } 1595 /* Note: $argN starts from $arg1 */ 1596 ret = sprint_nth_btf_arg(n - 1, type, buf + used, 1597 bufsize - used, ctx); 1598 if (ret < 0) 1599 goto error; 1600 new_argv[j++] = buf + used; 1601 used += ret + 1; 1602 } else 1603 new_argv[j++] = argv[i]; 1604 } 1605 1606 return new_argv; 1607 1608 error: 1609 kfree(new_argv); 1610 return ERR_PTR(ret); 1611 } 1612 1613 void traceprobe_finish_parse(struct traceprobe_parse_context *ctx) 1614 { 1615 clear_btf_context(ctx); 1616 } 1617 1618 int traceprobe_update_arg(struct probe_arg *arg) 1619 { 1620 struct fetch_insn *code = arg->code; 1621 long offset; 1622 char *tmp; 1623 char c; 1624 int ret = 0; 1625 1626 while (code && code->op != FETCH_OP_END) { 1627 if (code->op == FETCH_NOP_SYMBOL) { 1628 if (code[1].op != FETCH_OP_IMM) 1629 return -EINVAL; 1630 1631 tmp = strpbrk(code->data, "+-"); 1632 if (tmp) 1633 c = *tmp; 1634 ret = traceprobe_split_symbol_offset(code->data, 1635 &offset); 1636 if (ret) 1637 return ret; 1638 1639 code[1].immediate = 1640 (unsigned long)kallsyms_lookup_name(code->data); 1641 if (tmp) 1642 *tmp = c; 1643 if (!code[1].immediate) 1644 return -ENOENT; 1645 code[1].immediate += offset; 1646 } 1647 code++; 1648 } 1649 return 0; 1650 } 1651 1652 /* When len=0, we just calculate the needed length */ 1653 #define LEN_OR_ZERO (len ? len - pos : 0) 1654 static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, 1655 enum probe_print_type ptype) 1656 { 1657 struct probe_arg *parg; 1658 int i, j; 1659 int pos = 0; 1660 const char *fmt, *arg; 1661 1662 switch (ptype) { 1663 case PROBE_PRINT_NORMAL: 1664 fmt = "(%lx)"; 1665 arg = ", REC->" FIELD_STRING_IP; 1666 break; 1667 case PROBE_PRINT_RETURN: 1668 fmt = "(%lx <- %lx)"; 1669 arg = ", REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; 1670 break; 1671 case PROBE_PRINT_EVENT: 1672 fmt = ""; 1673 arg = ""; 1674 break; 1675 default: 1676 WARN_ON_ONCE(1); 1677 return 0; 1678 } 1679 1680 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt); 1681 1682 for (i = 0; i < tp->nr_args; i++) { 1683 parg = tp->args + i; 1684 pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); 1685 if (parg->count) { 1686 pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", 1687 parg->type->fmt); 1688 for (j = 1; j < parg->count; j++) 1689 pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", 1690 parg->type->fmt); 1691 pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); 1692 } else 1693 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", 1694 parg->type->fmt); 1695 } 1696 1697 pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", arg); 1698 1699 for (i = 0; i < tp->nr_args; i++) { 1700 parg = tp->args + i; 1701 if (parg->count) { 1702 if (parg->type->is_string) 1703 fmt = ", __get_str(%s[%d])"; 1704 else 1705 fmt = ", REC->%s[%d]"; 1706 for (j = 0; j < parg->count; j++) 1707 pos += snprintf(buf + pos, LEN_OR_ZERO, 1708 fmt, parg->name, j); 1709 } else { 1710 if (parg->type->is_string) 1711 fmt = ", __get_str(%s)"; 1712 else 1713 fmt = ", REC->%s"; 1714 pos += snprintf(buf + pos, LEN_OR_ZERO, 1715 fmt, parg->name); 1716 } 1717 } 1718 1719 /* return the length of print_fmt */ 1720 return pos; 1721 } 1722 #undef LEN_OR_ZERO 1723 1724 int traceprobe_set_print_fmt(struct trace_probe *tp, enum probe_print_type ptype) 1725 { 1726 struct trace_event_call *call = trace_probe_event_call(tp); 1727 int len; 1728 char *print_fmt; 1729 1730 /* First: called with 0 length to calculate the needed length */ 1731 len = __set_print_fmt(tp, NULL, 0, ptype); 1732 print_fmt = kmalloc(len + 1, GFP_KERNEL); 1733 if (!print_fmt) 1734 return -ENOMEM; 1735 1736 /* Second: actually write the @print_fmt */ 1737 __set_print_fmt(tp, print_fmt, len + 1, ptype); 1738 call->print_fmt = print_fmt; 1739 1740 return 0; 1741 } 1742 1743 int traceprobe_define_arg_fields(struct trace_event_call *event_call, 1744 size_t offset, struct trace_probe *tp) 1745 { 1746 int ret, i; 1747 1748 /* Set argument names as fields */ 1749 for (i = 0; i < tp->nr_args; i++) { 1750 struct probe_arg *parg = &tp->args[i]; 1751 const char *fmt = parg->type->fmttype; 1752 int size = parg->type->size; 1753 1754 if (parg->fmt) 1755 fmt = parg->fmt; 1756 if (parg->count) 1757 size *= parg->count; 1758 ret = trace_define_field(event_call, fmt, parg->name, 1759 offset + parg->offset, size, 1760 parg->type->is_signed, 1761 FILTER_OTHER); 1762 if (ret) 1763 return ret; 1764 } 1765 return 0; 1766 } 1767 1768 static void trace_probe_event_free(struct trace_probe_event *tpe) 1769 { 1770 kfree(tpe->class.system); 1771 kfree(tpe->call.name); 1772 kfree(tpe->call.print_fmt); 1773 kfree(tpe); 1774 } 1775 1776 int trace_probe_append(struct trace_probe *tp, struct trace_probe *to) 1777 { 1778 if (trace_probe_has_sibling(tp)) 1779 return -EBUSY; 1780 1781 list_del_init(&tp->list); 1782 trace_probe_event_free(tp->event); 1783 1784 tp->event = to->event; 1785 list_add_tail(&tp->list, trace_probe_probe_list(to)); 1786 1787 return 0; 1788 } 1789 1790 void trace_probe_unlink(struct trace_probe *tp) 1791 { 1792 list_del_init(&tp->list); 1793 if (list_empty(trace_probe_probe_list(tp))) 1794 trace_probe_event_free(tp->event); 1795 tp->event = NULL; 1796 } 1797 1798 void trace_probe_cleanup(struct trace_probe *tp) 1799 { 1800 int i; 1801 1802 for (i = 0; i < tp->nr_args; i++) 1803 traceprobe_free_probe_arg(&tp->args[i]); 1804 1805 if (tp->event) 1806 trace_probe_unlink(tp); 1807 } 1808 1809 int trace_probe_init(struct trace_probe *tp, const char *event, 1810 const char *group, bool alloc_filter, int nargs) 1811 { 1812 struct trace_event_call *call; 1813 size_t size = sizeof(struct trace_probe_event); 1814 int ret = 0; 1815 1816 if (!event || !group) 1817 return -EINVAL; 1818 1819 if (alloc_filter) 1820 size += sizeof(struct trace_uprobe_filter); 1821 1822 tp->event = kzalloc(size, GFP_KERNEL); 1823 if (!tp->event) 1824 return -ENOMEM; 1825 1826 INIT_LIST_HEAD(&tp->event->files); 1827 INIT_LIST_HEAD(&tp->event->class.fields); 1828 INIT_LIST_HEAD(&tp->event->probes); 1829 INIT_LIST_HEAD(&tp->list); 1830 list_add(&tp->list, &tp->event->probes); 1831 1832 call = trace_probe_event_call(tp); 1833 call->class = &tp->event->class; 1834 call->name = kstrdup(event, GFP_KERNEL); 1835 if (!call->name) { 1836 ret = -ENOMEM; 1837 goto error; 1838 } 1839 1840 tp->event->class.system = kstrdup(group, GFP_KERNEL); 1841 if (!tp->event->class.system) { 1842 ret = -ENOMEM; 1843 goto error; 1844 } 1845 1846 tp->nr_args = nargs; 1847 /* Make sure pointers in args[] are NULL */ 1848 if (nargs) 1849 memset(tp->args, 0, sizeof(tp->args[0]) * nargs); 1850 1851 return 0; 1852 1853 error: 1854 trace_probe_cleanup(tp); 1855 return ret; 1856 } 1857 1858 static struct trace_event_call * 1859 find_trace_event_call(const char *system, const char *event_name) 1860 { 1861 struct trace_event_call *tp_event; 1862 const char *name; 1863 1864 list_for_each_entry(tp_event, &ftrace_events, list) { 1865 if (!tp_event->class->system || 1866 strcmp(system, tp_event->class->system)) 1867 continue; 1868 name = trace_event_name(tp_event); 1869 if (!name || strcmp(event_name, name)) 1870 continue; 1871 return tp_event; 1872 } 1873 1874 return NULL; 1875 } 1876 1877 int trace_probe_register_event_call(struct trace_probe *tp) 1878 { 1879 struct trace_event_call *call = trace_probe_event_call(tp); 1880 int ret; 1881 1882 lockdep_assert_held(&event_mutex); 1883 1884 if (find_trace_event_call(trace_probe_group_name(tp), 1885 trace_probe_name(tp))) 1886 return -EEXIST; 1887 1888 ret = register_trace_event(&call->event); 1889 if (!ret) 1890 return -ENODEV; 1891 1892 ret = trace_add_event_call(call); 1893 if (ret) 1894 unregister_trace_event(&call->event); 1895 1896 return ret; 1897 } 1898 1899 int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file) 1900 { 1901 struct event_file_link *link; 1902 1903 link = kmalloc(sizeof(*link), GFP_KERNEL); 1904 if (!link) 1905 return -ENOMEM; 1906 1907 link->file = file; 1908 INIT_LIST_HEAD(&link->list); 1909 list_add_tail_rcu(&link->list, &tp->event->files); 1910 trace_probe_set_flag(tp, TP_FLAG_TRACE); 1911 return 0; 1912 } 1913 1914 struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp, 1915 struct trace_event_file *file) 1916 { 1917 struct event_file_link *link; 1918 1919 trace_probe_for_each_link(link, tp) { 1920 if (link->file == file) 1921 return link; 1922 } 1923 1924 return NULL; 1925 } 1926 1927 int trace_probe_remove_file(struct trace_probe *tp, 1928 struct trace_event_file *file) 1929 { 1930 struct event_file_link *link; 1931 1932 link = trace_probe_get_file_link(tp, file); 1933 if (!link) 1934 return -ENOENT; 1935 1936 list_del_rcu(&link->list); 1937 kvfree_rcu_mightsleep(link); 1938 1939 if (list_empty(&tp->event->files)) 1940 trace_probe_clear_flag(tp, TP_FLAG_TRACE); 1941 1942 return 0; 1943 } 1944 1945 /* 1946 * Return the smallest index of different type argument (start from 1). 1947 * If all argument types and name are same, return 0. 1948 */ 1949 int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b) 1950 { 1951 int i; 1952 1953 /* In case of more arguments */ 1954 if (a->nr_args < b->nr_args) 1955 return a->nr_args + 1; 1956 if (a->nr_args > b->nr_args) 1957 return b->nr_args + 1; 1958 1959 for (i = 0; i < a->nr_args; i++) { 1960 if ((b->nr_args <= i) || 1961 ((a->args[i].type != b->args[i].type) || 1962 (a->args[i].count != b->args[i].count) || 1963 strcmp(a->args[i].name, b->args[i].name))) 1964 return i + 1; 1965 } 1966 1967 return 0; 1968 } 1969 1970 bool trace_probe_match_command_args(struct trace_probe *tp, 1971 int argc, const char **argv) 1972 { 1973 char buf[MAX_ARGSTR_LEN + 1]; 1974 int i; 1975 1976 if (tp->nr_args < argc) 1977 return false; 1978 1979 for (i = 0; i < argc; i++) { 1980 snprintf(buf, sizeof(buf), "%s=%s", 1981 tp->args[i].name, tp->args[i].comm); 1982 if (strcmp(buf, argv[i])) 1983 return false; 1984 } 1985 return true; 1986 } 1987 1988 int trace_probe_create(const char *raw_command, int (*createfn)(int, const char **)) 1989 { 1990 int argc = 0, ret = 0; 1991 char **argv; 1992 1993 argv = argv_split(GFP_KERNEL, raw_command, &argc); 1994 if (!argv) 1995 return -ENOMEM; 1996 1997 if (argc) 1998 ret = createfn(argc, (const char **)argv); 1999 2000 argv_free(argv); 2001 2002 return ret; 2003 } 2004 2005 int trace_probe_print_args(struct trace_seq *s, struct probe_arg *args, int nr_args, 2006 u8 *data, void *field) 2007 { 2008 void *p; 2009 int i, j; 2010 2011 for (i = 0; i < nr_args; i++) { 2012 struct probe_arg *a = args + i; 2013 2014 trace_seq_printf(s, " %s=", a->name); 2015 if (likely(!a->count)) { 2016 if (!a->type->print(s, data + a->offset, field)) 2017 return -ENOMEM; 2018 continue; 2019 } 2020 trace_seq_putc(s, '{'); 2021 p = data + a->offset; 2022 for (j = 0; j < a->count; j++) { 2023 if (!a->type->print(s, p, field)) 2024 return -ENOMEM; 2025 trace_seq_putc(s, j == a->count - 1 ? '}' : ','); 2026 p += a->type->size; 2027 } 2028 } 2029 return 0; 2030 } 2031