kernel/trace/trace_events_synth.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * trace_events_synth - synthetic trace events
   4  *
   5  * Copyright (C) 2015, 2020 Tom Zanussi <tom.zanussi@linux.intel.com>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kallsyms.h>
  10 #include <linux/security.h>
  11 #include <linux/mutex.h>
  12 #include <linux/slab.h>
  13 #include <linux/stacktrace.h>
  14 #include <linux/rculist.h>
  15 #include <linux/tracefs.h>
  16
  17 /* for gfp flag names */
  18 #include <linux/trace_events.h>
  19 #include <trace/events/mmflags.h>
  20
  21 #include "trace_synth.h"
  22
  23 #undef ERRORS
  24 #define ERRORS  \
  25         C(BAD_NAME,             "Illegal name"),                \
  26         C(CMD_INCOMPLETE,       "Incomplete command"),          \
  27         C(EVENT_EXISTS,         "Event already exists"),        \
  28         C(TOO_MANY_FIELDS,      "Too many fields"),             \
  29         C(INCOMPLETE_TYPE,      "Incomplete type"),             \
  30         C(INVALID_TYPE,         "Invalid type"),                \
  31         C(INVALID_FIELD,        "Invalid field"),               \
  32         C(CMD_TOO_LONG,         "Command too long"),
  33
  34 #undef C
  35 #define C(a, b)         SYNTH_ERR_##a
  36
  37 enum { ERRORS };
  38
  39 #undef C
  40 #define C(a, b)         b
  41
  42 static const char *err_text[] = { ERRORS };
  43
  44 static char last_cmd[MAX_FILTER_STR_VAL];
  45
  46 static int errpos(const char *str)
  47 {
  48         return err_pos(last_cmd, str);
  49 }
  50
  51 static void last_cmd_set(char *str)
  52 {
  53         if (!str)
  54                 return;
  55
  56         strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
  57 }
  58
  59 static void synth_err(u8 err_type, u8 err_pos)
  60 {
  61         tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
  62                         err_type, err_pos);
  63 }
  64
  65 static int create_synth_event(int argc, const char **argv);
  66 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
  67 static int synth_event_release(struct dyn_event *ev);
  68 static bool synth_event_is_busy(struct dyn_event *ev);
  69 static bool synth_event_match(const char *system, const char *event,
  70                         int argc, const char **argv, struct dyn_event *ev);
  71
  72 static struct dyn_event_operations synth_event_ops = {
  73         .create = create_synth_event,
  74         .show = synth_event_show,
  75         .is_busy = synth_event_is_busy,
  76         .free = synth_event_release,
  77         .match = synth_event_match,
  78 };
  79
  80 static bool is_synth_event(struct dyn_event *ev)
  81 {
  82         return ev->ops == &synth_event_ops;
  83 }
  84
  85 static struct synth_event *to_synth_event(struct dyn_event *ev)
  86 {
  87         return container_of(ev, struct synth_event, devent);
  88 }
  89
  90 static bool synth_event_is_busy(struct dyn_event *ev)
  91 {
  92         struct synth_event *event = to_synth_event(ev);
  93
  94         return event->ref != 0;
  95 }
  96
  97 static bool synth_event_match(const char *system, const char *event,
  98                         int argc, const char **argv, struct dyn_event *ev)
  99 {
 100         struct synth_event *sev = to_synth_event(ev);
 101
 102         return strcmp(sev->name, event) == 0 &&
 103                 (!system || strcmp(system, SYNTH_SYSTEM) == 0);
 104 }
 105
 106 struct synth_trace_event {
 107         struct trace_entry      ent;
 108         u64                     fields[];
 109 };
 110
 111 static int synth_event_define_fields(struct trace_event_call *call)
 112 {
 113         struct synth_trace_event trace;
 114         int offset = offsetof(typeof(trace), fields);
 115         struct synth_event *event = call->data;
 116         unsigned int i, size, n_u64;
 117         char *name, *type;
 118         bool is_signed;
 119         int ret = 0;
 120
 121         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 122                 size = event->fields[i]->size;
 123                 is_signed = event->fields[i]->is_signed;
 124                 type = event->fields[i]->type;
 125                 name = event->fields[i]->name;
 126                 ret = trace_define_field(call, type, name, offset, size,
 127                                          is_signed, FILTER_OTHER);
 128                 if (ret)
 129                         break;
 130
 131                 event->fields[i]->offset = n_u64;
 132
 133                 if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
 134                         offset += STR_VAR_LEN_MAX;
 135                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 136                 } else {
 137                         offset += sizeof(u64);
 138                         n_u64++;
 139                 }
 140         }
 141
 142         event->n_u64 = n_u64;
 143
 144         return ret;
 145 }
 146
 147 static bool synth_field_signed(char *type)
 148 {
 149         if (str_has_prefix(type, "u"))
 150                 return false;
 151         if (strcmp(type, "gfp_t") == 0)
 152                 return false;
 153
 154         return true;
 155 }
 156
 157 static int synth_field_is_string(char *type)
 158 {
 159         if (strstr(type, "char[") != NULL)
 160                 return true;
 161
 162         return false;
 163 }
 164
 165 static int synth_field_string_size(char *type)
 166 {
 167         char buf[4], *end, *start;
 168         unsigned int len;
 169         int size, err;
 170
 171         start = strstr(type, "char[");
 172         if (start == NULL)
 173                 return -EINVAL;
 174         start += sizeof("char[") - 1;
 175
 176         end = strchr(type, ']');
 177         if (!end || end < start || type + strlen(type) > end + 1)
 178                 return -EINVAL;
 179
 180         len = end - start;
 181         if (len > 3)
 182                 return -EINVAL;
 183
 184         if (len == 0)
 185                 return 0; /* variable-length string */
 186
 187         strncpy(buf, start, len);
 188         buf[len] = '\0';
 189
 190         err = kstrtouint(buf, 0, &size);
 191         if (err)
 192                 return err;
 193
 194         if (size > STR_VAR_LEN_MAX)
 195                 return -EINVAL;
 196
 197         return size;
 198 }
 199
 200 static int synth_field_size(char *type)
 201 {
 202         int size = 0;
 203
 204         if (strcmp(type, "s64") == 0)
 205                 size = sizeof(s64);
 206         else if (strcmp(type, "u64") == 0)
 207                 size = sizeof(u64);
 208         else if (strcmp(type, "s32") == 0)
 209                 size = sizeof(s32);
 210         else if (strcmp(type, "u32") == 0)
 211                 size = sizeof(u32);
 212         else if (strcmp(type, "s16") == 0)
 213                 size = sizeof(s16);
 214         else if (strcmp(type, "u16") == 0)
 215                 size = sizeof(u16);
 216         else if (strcmp(type, "s8") == 0)
 217                 size = sizeof(s8);
 218         else if (strcmp(type, "u8") == 0)
 219                 size = sizeof(u8);
 220         else if (strcmp(type, "char") == 0)
 221                 size = sizeof(char);
 222         else if (strcmp(type, "unsigned char") == 0)
 223                 size = sizeof(unsigned char);
 224         else if (strcmp(type, "int") == 0)
 225                 size = sizeof(int);
 226         else if (strcmp(type, "unsigned int") == 0)
 227                 size = sizeof(unsigned int);
 228         else if (strcmp(type, "long") == 0)
 229                 size = sizeof(long);
 230         else if (strcmp(type, "unsigned long") == 0)
 231                 size = sizeof(unsigned long);
 232         else if (strcmp(type, "bool") == 0)
 233                 size = sizeof(bool);
 234         else if (strcmp(type, "pid_t") == 0)
 235                 size = sizeof(pid_t);
 236         else if (strcmp(type, "gfp_t") == 0)
 237                 size = sizeof(gfp_t);
 238         else if (synth_field_is_string(type))
 239                 size = synth_field_string_size(type);
 240
 241         return size;
 242 }
 243
 244 static const char *synth_field_fmt(char *type)
 245 {
 246         const char *fmt = "%llu";
 247
 248         if (strcmp(type, "s64") == 0)
 249                 fmt = "%lld";
 250         else if (strcmp(type, "u64") == 0)
 251                 fmt = "%llu";
 252         else if (strcmp(type, "s32") == 0)
 253                 fmt = "%d";
 254         else if (strcmp(type, "u32") == 0)
 255                 fmt = "%u";
 256         else if (strcmp(type, "s16") == 0)
 257                 fmt = "%d";
 258         else if (strcmp(type, "u16") == 0)
 259                 fmt = "%u";
 260         else if (strcmp(type, "s8") == 0)
 261                 fmt = "%d";
 262         else if (strcmp(type, "u8") == 0)
 263                 fmt = "%u";
 264         else if (strcmp(type, "char") == 0)
 265                 fmt = "%d";
 266         else if (strcmp(type, "unsigned char") == 0)
 267                 fmt = "%u";
 268         else if (strcmp(type, "int") == 0)
 269                 fmt = "%d";
 270         else if (strcmp(type, "unsigned int") == 0)
 271                 fmt = "%u";
 272         else if (strcmp(type, "long") == 0)
 273                 fmt = "%ld";
 274         else if (strcmp(type, "unsigned long") == 0)
 275                 fmt = "%lu";
 276         else if (strcmp(type, "bool") == 0)
 277                 fmt = "%d";
 278         else if (strcmp(type, "pid_t") == 0)
 279                 fmt = "%d";
 280         else if (strcmp(type, "gfp_t") == 0)
 281                 fmt = "%x";
 282         else if (synth_field_is_string(type))
 283                 fmt = "%.*s";
 284
 285         return fmt;
 286 }
 287
 288 static void print_synth_event_num_val(struct trace_seq *s,
 289                                       char *print_fmt, char *name,
 290                                       int size, u64 val, char *space)
 291 {
 292         switch (size) {
 293         case 1:
 294                 trace_seq_printf(s, print_fmt, name, (u8)val, space);
 295                 break;
 296
 297         case 2:
 298                 trace_seq_printf(s, print_fmt, name, (u16)val, space);
 299                 break;
 300
 301         case 4:
 302                 trace_seq_printf(s, print_fmt, name, (u32)val, space);
 303                 break;
 304
 305         default:
 306                 trace_seq_printf(s, print_fmt, name, val, space);
 307                 break;
 308         }
 309 }
 310
 311 static enum print_line_t print_synth_event(struct trace_iterator *iter,
 312                                            int flags,
 313                                            struct trace_event *event)
 314 {
 315         struct trace_array *tr = iter->tr;
 316         struct trace_seq *s = &iter->seq;
 317         struct synth_trace_event *entry;
 318         struct synth_event *se;
 319         unsigned int i, n_u64;
 320         char print_fmt[32];
 321         const char *fmt;
 322
 323         entry = (struct synth_trace_event *)iter->ent;
 324         se = container_of(event, struct synth_event, call.event);
 325
 326         trace_seq_printf(s, "%s: ", se->name);
 327
 328         for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
 329                 if (trace_seq_has_overflowed(s))
 330                         goto end;
 331
 332                 fmt = synth_field_fmt(se->fields[i]->type);
 333
 334                 /* parameter types */
 335                 if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
 336                         trace_seq_printf(s, "%s ", fmt);
 337
 338                 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
 339
 340                 /* parameter values */
 341                 if (se->fields[i]->is_string) {
 342                         if (se->fields[i]->is_dynamic) {
 343                                 u32 offset, data_offset;
 344                                 char *str_field;
 345
 346                                 offset = (u32)entry->fields[n_u64];
 347                                 data_offset = offset & 0xffff;
 348
 349                                 str_field = (char *)entry + data_offset;
 350
 351                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 352                                                  STR_VAR_LEN_MAX,
 353                                                  str_field,
 354                                                  i == se->n_fields - 1 ? "" : " ");
 355                                 n_u64++;
 356                         } else {
 357                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 358                                                  STR_VAR_LEN_MAX,
 359                                                  (char *)&entry->fields[n_u64],
 360                                                  i == se->n_fields - 1 ? "" : " ");
 361                                 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 362                         }
 363                 } else {
 364                         struct trace_print_flags __flags[] = {
 365                             __def_gfpflag_names, {-1, NULL} };
 366                         char *space = (i == se->n_fields - 1 ? "" : " ");
 367
 368                         print_synth_event_num_val(s, print_fmt,
 369                                                   se->fields[i]->name,
 370                                                   se->fields[i]->size,
 371                                                   entry->fields[n_u64],
 372                                                   space);
 373
 374                         if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
 375                                 trace_seq_puts(s, " (");
 376                                 trace_print_flags_seq(s, "|",
 377                                                       entry->fields[n_u64],
 378                                                       __flags);
 379                                 trace_seq_putc(s, ')');
 380                         }
 381                         n_u64++;
 382                 }
 383         }
 384 end:
 385         trace_seq_putc(s, '\n');
 386
 387         return trace_handle_return(s);
 388 }
 389
 390 static struct trace_event_functions synth_event_funcs = {
 391         .trace          = print_synth_event
 392 };
 393
 394 static unsigned int trace_string(struct synth_trace_event *entry,
 395                                  struct synth_event *event,
 396                                  char *str_val,
 397                                  bool is_dynamic,
 398                                  unsigned int data_size,
 399                                  unsigned int *n_u64)
 400 {
 401         unsigned int len = 0;
 402         char *str_field;
 403
 404         if (is_dynamic) {
 405                 u32 data_offset;
 406
 407                 data_offset = offsetof(typeof(*entry), fields);
 408                 data_offset += event->n_u64 * sizeof(u64);
 409                 data_offset += data_size;
 410
 411                 str_field = (char *)entry + data_offset;
 412
 413                 len = strlen(str_val) + 1;
 414                 strscpy(str_field, str_val, len);
 415
 416                 data_offset |= len << 16;
 417                 *(u32 *)&entry->fields[*n_u64] = data_offset;
 418
 419                 (*n_u64)++;
 420         } else {
 421                 str_field = (char *)&entry->fields[*n_u64];
 422
 423                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
 424                 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
 425         }
 426
 427         return len;
 428 }
 429
 430 static notrace void trace_event_raw_event_synth(void *__data,
 431                                                 u64 *var_ref_vals,
 432                                                 unsigned int *var_ref_idx)
 433 {
 434         unsigned int i, n_u64, val_idx, len, data_size = 0;
 435         struct trace_event_file *trace_file = __data;
 436         struct synth_trace_event *entry;
 437         struct trace_event_buffer fbuffer;
 438         struct trace_buffer *buffer;
 439         struct synth_event *event;
 440         int fields_size = 0;
 441
 442         event = trace_file->event_call->data;
 443
 444         if (trace_trigger_soft_disabled(trace_file))
 445                 return;
 446
 447         fields_size = event->n_u64 * sizeof(u64);
 448
 449         for (i = 0; i < event->n_dynamic_fields; i++) {
 450                 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
 451                 char *str_val;
 452
 453                 val_idx = var_ref_idx[field_pos];
 454                 str_val = (char *)(long)var_ref_vals[val_idx];
 455
 456                 len = strlen(str_val) + 1;
 457
 458                 fields_size += len;
 459         }
 460
 461         /*
 462          * Avoid ring buffer recursion detection, as this event
 463          * is being performed within another event.
 464          */
 465         buffer = trace_file->tr->array_buffer.buffer;
 466         ring_buffer_nest_start(buffer);
 467
 468         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 469                                            sizeof(*entry) + fields_size);
 470         if (!entry)
 471                 goto out;
 472
 473         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 474                 val_idx = var_ref_idx[i];
 475                 if (event->fields[i]->is_string) {
 476                         char *str_val = (char *)(long)var_ref_vals[val_idx];
 477
 478                         len = trace_string(entry, event, str_val,
 479                                            event->fields[i]->is_dynamic,
 480                                            data_size, &n_u64);
 481                         data_size += len; /* only dynamic string increments */
 482                 } else {
 483                         struct synth_field *field = event->fields[i];
 484                         u64 val = var_ref_vals[val_idx];
 485
 486                         switch (field->size) {
 487                         case 1:
 488                                 *(u8 *)&entry->fields[n_u64] = (u8)val;
 489                                 break;
 490
 491                         case 2:
 492                                 *(u16 *)&entry->fields[n_u64] = (u16)val;
 493                                 break;
 494
 495                         case 4:
 496                                 *(u32 *)&entry->fields[n_u64] = (u32)val;
 497                                 break;
 498
 499                         default:
 500                                 entry->fields[n_u64] = val;
 501                                 break;
 502                         }
 503                         n_u64++;
 504                 }
 505         }
 506
 507         trace_event_buffer_commit(&fbuffer);
 508 out:
 509         ring_buffer_nest_end(buffer);
 510 }
 511
 512 static void free_synth_event_print_fmt(struct trace_event_call *call)
 513 {
 514         if (call) {
 515                 kfree(call->print_fmt);
 516                 call->print_fmt = NULL;
 517         }
 518 }
 519
 520 static int __set_synth_event_print_fmt(struct synth_event *event,
 521                                        char *buf, int len)
 522 {
 523         const char *fmt;
 524         int pos = 0;
 525         int i;
 526
 527         /* When len=0, we just calculate the needed length */
 528 #define LEN_OR_ZERO (len ? len - pos : 0)
 529
 530         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 531         for (i = 0; i < event->n_fields; i++) {
 532                 fmt = synth_field_fmt(event->fields[i]->type);
 533                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 534                                 event->fields[i]->name, fmt,
 535                                 i == event->n_fields - 1 ? "" : ", ");
 536         }
 537         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 538
 539         for (i = 0; i < event->n_fields; i++) {
 540                 if (event->fields[i]->is_string &&
 541                     event->fields[i]->is_dynamic)
 542                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 543                                 ", __get_str(%s)", event->fields[i]->name);
 544                 else
 545                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 546                                         ", REC->%s", event->fields[i]->name);
 547         }
 548
 549 #undef LEN_OR_ZERO
 550
 551         /* return the length of print_fmt */
 552         return pos;
 553 }
 554
 555 static int set_synth_event_print_fmt(struct trace_event_call *call)
 556 {
 557         struct synth_event *event = call->data;
 558         char *print_fmt;
 559         int len;
 560
 561         /* First: called with 0 length to calculate the needed length */
 562         len = __set_synth_event_print_fmt(event, NULL, 0);
 563
 564         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 565         if (!print_fmt)
 566                 return -ENOMEM;
 567
 568         /* Second: actually write the @print_fmt */
 569         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 570         call->print_fmt = print_fmt;
 571
 572         return 0;
 573 }
 574
 575 static void free_synth_field(struct synth_field *field)
 576 {
 577         kfree(field->type);
 578         kfree(field->name);
 579         kfree(field);
 580 }
 581
 582 static struct synth_field *parse_synth_field(int argc, const char **argv,
 583                                              int *consumed)
 584 {
 585         struct synth_field *field;
 586         const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 587         int len, ret = 0;
 588         ssize_t size;
 589
 590         if (field_type[0] == ';')
 591                 field_type++;
 592
 593         if (!strcmp(field_type, "unsigned")) {
 594                 if (argc < 3) {
 595                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 596                         return ERR_PTR(-EINVAL);
 597                 }
 598                 prefix = "unsigned ";
 599                 field_type = argv[1];
 600                 field_name = argv[2];
 601                 *consumed = 3;
 602         } else {
 603                 field_name = argv[1];
 604                 *consumed = 2;
 605         }
 606
 607         field = kzalloc(sizeof(*field), GFP_KERNEL);
 608         if (!field)
 609                 return ERR_PTR(-ENOMEM);
 610
 611         len = strlen(field_name);
 612         array = strchr(field_name, '[');
 613         if (array)
 614                 len -= strlen(array);
 615         else if (field_name[len - 1] == ';')
 616                 len--;
 617
 618         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 619         if (!field->name) {
 620                 ret = -ENOMEM;
 621                 goto free;
 622         }
 623         if (!is_good_name(field->name)) {
 624                 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 625                 ret = -EINVAL;
 626                 goto free;
 627         }
 628
 629         if (field_type[0] == ';')
 630                 field_type++;
 631         len = strlen(field_type) + 1;
 632
 633         if (array) {
 634                 int l = strlen(array);
 635
 636                 if (l && array[l - 1] == ';')
 637                         l--;
 638                 len += l;
 639         }
 640         if (prefix)
 641                 len += strlen(prefix);
 642
 643         field->type = kzalloc(len, GFP_KERNEL);
 644         if (!field->type) {
 645                 ret = -ENOMEM;
 646                 goto free;
 647         }
 648         if (prefix)
 649                 strcat(field->type, prefix);
 650         strcat(field->type, field_type);
 651         if (array) {
 652                 strcat(field->type, array);
 653                 if (field->type[len - 1] == ';')
 654                         field->type[len - 1] = '\0';
 655         }
 656
 657         size = synth_field_size(field->type);
 658         if (size < 0) {
 659                 synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 660                 ret = -EINVAL;
 661                 goto free;
 662         } else if (size == 0) {
 663                 if (synth_field_is_string(field->type)) {
 664                         char *type;
 665
 666                         type = kzalloc(sizeof("__data_loc ") + strlen(field->type) + 1, GFP_KERNEL);
 667                         if (!type) {
 668                                 ret = -ENOMEM;
 669                                 goto free;
 670                         }
 671
 672                         strcat(type, "__data_loc ");
 673                         strcat(type, field->type);
 674                         kfree(field->type);
 675                         field->type = type;
 676
 677                         field->is_dynamic = true;
 678                         size = sizeof(u64);
 679                 } else {
 680                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 681                         ret = -EINVAL;
 682                         goto free;
 683                 }
 684         }
 685         field->size = size;
 686
 687         if (synth_field_is_string(field->type))
 688                 field->is_string = true;
 689
 690         field->is_signed = synth_field_signed(field->type);
 691  out:
 692         return field;
 693  free:
 694         free_synth_field(field);
 695         field = ERR_PTR(ret);
 696         goto out;
 697 }
 698
 699 static void free_synth_tracepoint(struct tracepoint *tp)
 700 {
 701         if (!tp)
 702                 return;
 703
 704         kfree(tp->name);
 705         kfree(tp);
 706 }
 707
 708 static struct tracepoint *alloc_synth_tracepoint(char *name)
 709 {
 710         struct tracepoint *tp;
 711
 712         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 713         if (!tp)
 714                 return ERR_PTR(-ENOMEM);
 715
 716         tp->name = kstrdup(name, GFP_KERNEL);
 717         if (!tp->name) {
 718                 kfree(tp);
 719                 return ERR_PTR(-ENOMEM);
 720         }
 721
 722         return tp;
 723 }
 724
 725 struct synth_event *find_synth_event(const char *name)
 726 {
 727         struct dyn_event *pos;
 728         struct synth_event *event;
 729
 730         for_each_dyn_event(pos) {
 731                 if (!is_synth_event(pos))
 732                         continue;
 733                 event = to_synth_event(pos);
 734                 if (strcmp(event->name, name) == 0)
 735                         return event;
 736         }
 737
 738         return NULL;
 739 }
 740
 741 static struct trace_event_fields synth_event_fields_array[] = {
 742         { .type = TRACE_FUNCTION_TYPE,
 743           .define_fields = synth_event_define_fields },
 744         {}
 745 };
 746
 747 static int register_synth_event(struct synth_event *event)
 748 {
 749         struct trace_event_call *call = &event->call;
 750         int ret = 0;
 751
 752         event->call.class = &event->class;
 753         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 754         if (!event->class.system) {
 755                 ret = -ENOMEM;
 756                 goto out;
 757         }
 758
 759         event->tp = alloc_synth_tracepoint(event->name);
 760         if (IS_ERR(event->tp)) {
 761                 ret = PTR_ERR(event->tp);
 762                 event->tp = NULL;
 763                 goto out;
 764         }
 765
 766         INIT_LIST_HEAD(&call->class->fields);
 767         call->event.funcs = &synth_event_funcs;
 768         call->class->fields_array = synth_event_fields_array;
 769
 770         ret = register_trace_event(&call->event);
 771         if (!ret) {
 772                 ret = -ENODEV;
 773                 goto out;
 774         }
 775         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 776         call->class->reg = trace_event_reg;
 777         call->class->probe = trace_event_raw_event_synth;
 778         call->data = event;
 779         call->tp = event->tp;
 780
 781         ret = trace_add_event_call(call);
 782         if (ret) {
 783                 pr_warn("Failed to register synthetic event: %s\n",
 784                         trace_event_name(call));
 785                 goto err;
 786         }
 787
 788         ret = set_synth_event_print_fmt(call);
 789         if (ret < 0) {
 790                 trace_remove_event_call(call);
 791                 goto err;
 792         }
 793  out:
 794         return ret;
 795  err:
 796         unregister_trace_event(&call->event);
 797         goto out;
 798 }
 799
 800 static int unregister_synth_event(struct synth_event *event)
 801 {
 802         struct trace_event_call *call = &event->call;
 803         int ret;
 804
 805         ret = trace_remove_event_call(call);
 806
 807         return ret;
 808 }
 809
 810 static void free_synth_event(struct synth_event *event)
 811 {
 812         unsigned int i;
 813
 814         if (!event)
 815                 return;
 816
 817         for (i = 0; i < event->n_fields; i++)
 818                 free_synth_field(event->fields[i]);
 819
 820         kfree(event->fields);
 821         kfree(event->dynamic_fields);
 822         kfree(event->name);
 823         kfree(event->class.system);
 824         free_synth_tracepoint(event->tp);
 825         free_synth_event_print_fmt(&event->call);
 826         kfree(event);
 827 }
 828
 829 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 830                                              struct synth_field **fields)
 831 {
 832         unsigned int i, j, n_dynamic_fields = 0;
 833         struct synth_event *event;
 834
 835         event = kzalloc(sizeof(*event), GFP_KERNEL);
 836         if (!event) {
 837                 event = ERR_PTR(-ENOMEM);
 838                 goto out;
 839         }
 840
 841         event->name = kstrdup(name, GFP_KERNEL);
 842         if (!event->name) {
 843                 kfree(event);
 844                 event = ERR_PTR(-ENOMEM);
 845                 goto out;
 846         }
 847
 848         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 849         if (!event->fields) {
 850                 free_synth_event(event);
 851                 event = ERR_PTR(-ENOMEM);
 852                 goto out;
 853         }
 854
 855         for (i = 0; i < n_fields; i++)
 856                 if (fields[i]->is_dynamic)
 857                         n_dynamic_fields++;
 858
 859         if (n_dynamic_fields) {
 860                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 861                                                 sizeof(*event->dynamic_fields),
 862                                                 GFP_KERNEL);
 863                 if (!event->dynamic_fields) {
 864                         free_synth_event(event);
 865                         event = ERR_PTR(-ENOMEM);
 866                         goto out;
 867                 }
 868         }
 869
 870         dyn_event_init(&event->devent, &synth_event_ops);
 871
 872         for (i = 0, j = 0; i < n_fields; i++) {
 873                 event->fields[i] = fields[i];
 874
 875                 if (fields[i]->is_dynamic) {
 876                         event->dynamic_fields[j] = fields[i];
 877                         event->dynamic_fields[j]->field_pos = i;
 878                         event->dynamic_fields[j++] = fields[i];
 879                         event->n_dynamic_fields++;
 880                 }
 881         }
 882         event->n_fields = n_fields;
 883  out:
 884         return event;
 885 }
 886
 887 static int synth_event_check_arg_fn(void *data)
 888 {
 889         struct dynevent_arg_pair *arg_pair = data;
 890         int size;
 891
 892         size = synth_field_size((char *)arg_pair->lhs);
 893         if (size == 0) {
 894                 if (strstr((char *)arg_pair->lhs, "["))
 895                         return 0;
 896         }
 897
 898         return size ? 0 : -EINVAL;
 899 }
 900
 901 /**
 902  * synth_event_add_field - Add a new field to a synthetic event cmd
 903  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 904  * @type: The type of the new field to add
 905  * @name: The name of the new field to add
 906  *
 907  * Add a new field to a synthetic event cmd object.  Field ordering is in
 908  * the same order the fields are added.
 909  *
 910  * See synth_field_size() for available types. If field_name contains
 911  * [n] the field is considered to be an array.
 912  *
 913  * Return: 0 if successful, error otherwise.
 914  */
 915 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
 916                           const char *name)
 917 {
 918         struct dynevent_arg_pair arg_pair;
 919         int ret;
 920
 921         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 922                 return -EINVAL;
 923
 924         if (!type || !name)
 925                 return -EINVAL;
 926
 927         dynevent_arg_pair_init(&arg_pair, 0, ';');
 928
 929         arg_pair.lhs = type;
 930         arg_pair.rhs = name;
 931
 932         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
 933         if (ret)
 934                 return ret;
 935
 936         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 937                 ret = -EINVAL;
 938
 939         return ret;
 940 }
 941 EXPORT_SYMBOL_GPL(synth_event_add_field);
 942
 943 /**
 944  * synth_event_add_field_str - Add a new field to a synthetic event cmd
 945  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 946  * @type_name: The type and name of the new field to add, as a single string
 947  *
 948  * Add a new field to a synthetic event cmd object, as a single
 949  * string.  The @type_name string is expected to be of the form 'type
 950  * name', which will be appended by ';'.  No sanity checking is done -
 951  * what's passed in is assumed to already be well-formed.  Field
 952  * ordering is in the same order the fields are added.
 953  *
 954  * See synth_field_size() for available types. If field_name contains
 955  * [n] the field is considered to be an array.
 956  *
 957  * Return: 0 if successful, error otherwise.
 958  */
 959 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
 960 {
 961         struct dynevent_arg arg;
 962         int ret;
 963
 964         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 965                 return -EINVAL;
 966
 967         if (!type_name)
 968                 return -EINVAL;
 969
 970         dynevent_arg_init(&arg, ';');
 971
 972         arg.str = type_name;
 973
 974         ret = dynevent_arg_add(cmd, &arg, NULL);
 975         if (ret)
 976                 return ret;
 977
 978         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 979                 ret = -EINVAL;
 980
 981         return ret;
 982 }
 983 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
 984
 985 /**
 986  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
 987  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 988  * @fields: An array of type/name field descriptions
 989  * @n_fields: The number of field descriptions contained in the fields array
 990  *
 991  * Add a new set of fields to a synthetic event cmd object.  The event
 992  * fields that will be defined for the event should be passed in as an
 993  * array of struct synth_field_desc, and the number of elements in the
 994  * array passed in as n_fields.  Field ordering will retain the
 995  * ordering given in the fields array.
 996  *
 997  * See synth_field_size() for available types. If field_name contains
 998  * [n] the field is considered to be an array.
 999  *
1000  * Return: 0 if successful, error otherwise.
1001  */
1002 int synth_event_add_fields(struct dynevent_cmd *cmd,
1003                            struct synth_field_desc *fields,
1004                            unsigned int n_fields)
1005 {
1006         unsigned int i;
1007         int ret = 0;
1008
1009         for (i = 0; i < n_fields; i++) {
1010                 if (fields[i].type == NULL || fields[i].name == NULL) {
1011                         ret = -EINVAL;
1012                         break;
1013                 }
1014
1015                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1016                 if (ret)
1017                         break;
1018         }
1019
1020         return ret;
1021 }
1022 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1023
1024 /**
1025  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1026  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1027  * @name: The name of the synthetic event
1028  * @mod: The module creating the event, NULL if not created from a module
1029  * @args: Variable number of arg (pairs), one pair for each field
1030  *
1031  * NOTE: Users normally won't want to call this function directly, but
1032  * rather use the synth_event_gen_cmd_start() wrapper, which
1033  * automatically adds a NULL to the end of the arg list.  If this
1034  * function is used directly, make sure the last arg in the variable
1035  * arg list is NULL.
1036  *
1037  * Generate a synthetic event command to be executed by
1038  * synth_event_gen_cmd_end().  This function can be used to generate
1039  * the complete command or only the first part of it; in the latter
1040  * case, synth_event_add_field(), synth_event_add_field_str(), or
1041  * synth_event_add_fields() can be used to add more fields following
1042  * this.
1043  *
1044  * There should be an even number variable args, each pair consisting
1045  * of a type followed by a field name.
1046  *
1047  * See synth_field_size() for available types. If field_name contains
1048  * [n] the field is considered to be an array.
1049  *
1050  * Return: 0 if successful, error otherwise.
1051  */
1052 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1053                                 struct module *mod, ...)
1054 {
1055         struct dynevent_arg arg;
1056         va_list args;
1057         int ret;
1058
1059         cmd->event_name = name;
1060         cmd->private_data = mod;
1061
1062         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1063                 return -EINVAL;
1064
1065         dynevent_arg_init(&arg, 0);
1066         arg.str = name;
1067         ret = dynevent_arg_add(cmd, &arg, NULL);
1068         if (ret)
1069                 return ret;
1070
1071         va_start(args, mod);
1072         for (;;) {
1073                 const char *type, *name;
1074
1075                 type = va_arg(args, const char *);
1076                 if (!type)
1077                         break;
1078                 name = va_arg(args, const char *);
1079                 if (!name)
1080                         break;
1081
1082                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1083                         ret = -EINVAL;
1084                         break;
1085                 }
1086
1087                 ret = synth_event_add_field(cmd, type, name);
1088                 if (ret)
1089                         break;
1090         }
1091         va_end(args);
1092
1093         return ret;
1094 }
1095 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1096
1097 /**
1098  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1099  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1100  * @name: The name of the synthetic event
1101  * @fields: An array of type/name field descriptions
1102  * @n_fields: The number of field descriptions contained in the fields array
1103  *
1104  * Generate a synthetic event command to be executed by
1105  * synth_event_gen_cmd_end().  This function can be used to generate
1106  * the complete command or only the first part of it; in the latter
1107  * case, synth_event_add_field(), synth_event_add_field_str(), or
1108  * synth_event_add_fields() can be used to add more fields following
1109  * this.
1110  *
1111  * The event fields that will be defined for the event should be
1112  * passed in as an array of struct synth_field_desc, and the number of
1113  * elements in the array passed in as n_fields.  Field ordering will
1114  * retain the ordering given in the fields array.
1115  *
1116  * See synth_field_size() for available types. If field_name contains
1117  * [n] the field is considered to be an array.
1118  *
1119  * Return: 0 if successful, error otherwise.
1120  */
1121 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1122                                     struct module *mod,
1123                                     struct synth_field_desc *fields,
1124                                     unsigned int n_fields)
1125 {
1126         struct dynevent_arg arg;
1127         unsigned int i;
1128         int ret = 0;
1129
1130         cmd->event_name = name;
1131         cmd->private_data = mod;
1132
1133         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1134                 return -EINVAL;
1135
1136         if (n_fields > SYNTH_FIELDS_MAX)
1137                 return -EINVAL;
1138
1139         dynevent_arg_init(&arg, 0);
1140         arg.str = name;
1141         ret = dynevent_arg_add(cmd, &arg, NULL);
1142         if (ret)
1143                 return ret;
1144
1145         for (i = 0; i < n_fields; i++) {
1146                 if (fields[i].type == NULL || fields[i].name == NULL)
1147                         return -EINVAL;
1148
1149                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1150                 if (ret)
1151                         break;
1152         }
1153
1154         return ret;
1155 }
1156 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1157
1158 static int save_cmdstr(int argc, const char *name, const char **argv)
1159 {
1160         struct seq_buf s;
1161         char *buf;
1162         int i;
1163
1164         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1165         if (!buf)
1166                 return -ENOMEM;
1167
1168         seq_buf_init(&s, buf, MAX_DYNEVENT_CMD_LEN);
1169
1170         seq_buf_puts(&s, name);
1171
1172         for (i = 0; i < argc; i++) {
1173                 seq_buf_putc(&s, ' ');
1174                 seq_buf_puts(&s, argv[i]);
1175         }
1176
1177         if (!seq_buf_buffer_left(&s)) {
1178                 synth_err(SYNTH_ERR_CMD_TOO_LONG, 0);
1179                 kfree(buf);
1180                 return -EINVAL;
1181         }
1182         buf[s.len] = 0;
1183         last_cmd_set(buf);
1184
1185         kfree(buf);
1186         return 0;
1187 }
1188
1189 static int __create_synth_event(int argc, const char *name, const char **argv)
1190 {
1191         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1192         struct synth_event *event = NULL;
1193         int i, consumed = 0, n_fields = 0, ret = 0;
1194
1195         ret = save_cmdstr(argc, name, argv);
1196         if (ret)
1197                 return ret;
1198
1199         /*
1200          * Argument syntax:
1201          *  - Add synthetic event: <event_name> field[;field] ...
1202          *  - Remove synthetic event: !<event_name> field[;field] ...
1203          *      where 'field' = type field_name
1204          */
1205
1206         if (name[0] == '\0' || argc < 1) {
1207                 synth_err(SYNTH_ERR_CMD_INCOMPLETE, 0);
1208                 return -EINVAL;
1209         }
1210
1211         mutex_lock(&event_mutex);
1212
1213         if (!is_good_name(name)) {
1214                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1215                 ret = -EINVAL;
1216                 goto out;
1217         }
1218
1219         event = find_synth_event(name);
1220         if (event) {
1221                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1222                 ret = -EEXIST;
1223                 goto out;
1224         }
1225
1226         for (i = 0; i < argc - 1; i++) {
1227                 if (strcmp(argv[i], ";") == 0)
1228                         continue;
1229                 if (n_fields == SYNTH_FIELDS_MAX) {
1230                         synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1231                         ret = -EINVAL;
1232                         goto err;
1233                 }
1234
1235                 field = parse_synth_field(argc - i, &argv[i], &consumed);
1236                 if (IS_ERR(field)) {
1237                         ret = PTR_ERR(field);
1238                         goto err;
1239                 }
1240                 fields[n_fields++] = field;
1241                 i += consumed - 1;
1242         }
1243
1244         if (i < argc && strcmp(argv[i], ";") != 0) {
1245                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(argv[i]));
1246                 ret = -EINVAL;
1247                 goto err;
1248         }
1249
1250         event = alloc_synth_event(name, n_fields, fields);
1251         if (IS_ERR(event)) {
1252                 ret = PTR_ERR(event);
1253                 event = NULL;
1254                 goto err;
1255         }
1256         ret = register_synth_event(event);
1257         if (!ret)
1258                 dyn_event_add(&event->devent);
1259         else
1260                 free_synth_event(event);
1261  out:
1262         mutex_unlock(&event_mutex);
1263
1264         return ret;
1265  err:
1266         for (i = 0; i < n_fields; i++)
1267                 free_synth_field(fields[i]);
1268
1269         goto out;
1270 }
1271
1272 /**
1273  * synth_event_create - Create a new synthetic event
1274  * @name: The name of the new sythetic event
1275  * @fields: An array of type/name field descriptions
1276  * @n_fields: The number of field descriptions contained in the fields array
1277  * @mod: The module creating the event, NULL if not created from a module
1278  *
1279  * Create a new synthetic event with the given name under the
1280  * trace/events/synthetic/ directory.  The event fields that will be
1281  * defined for the event should be passed in as an array of struct
1282  * synth_field_desc, and the number elements in the array passed in as
1283  * n_fields. Field ordering will retain the ordering given in the
1284  * fields array.
1285  *
1286  * If the new synthetic event is being created from a module, the mod
1287  * param must be non-NULL.  This will ensure that the trace buffer
1288  * won't contain unreadable events.
1289  *
1290  * The new synth event should be deleted using synth_event_delete()
1291  * function.  The new synthetic event can be generated from modules or
1292  * other kernel code using trace_synth_event() and related functions.
1293  *
1294  * Return: 0 if successful, error otherwise.
1295  */
1296 int synth_event_create(const char *name, struct synth_field_desc *fields,
1297                        unsigned int n_fields, struct module *mod)
1298 {
1299         struct dynevent_cmd cmd;
1300         char *buf;
1301         int ret;
1302
1303         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1304         if (!buf)
1305                 return -ENOMEM;
1306
1307         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1308
1309         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1310                                               fields, n_fields);
1311         if (ret)
1312                 goto out;
1313
1314         ret = synth_event_gen_cmd_end(&cmd);
1315  out:
1316         kfree(buf);
1317
1318         return ret;
1319 }
1320 EXPORT_SYMBOL_GPL(synth_event_create);
1321
1322 static int destroy_synth_event(struct synth_event *se)
1323 {
1324         int ret;
1325
1326         if (se->ref)
1327                 ret = -EBUSY;
1328         else {
1329                 ret = unregister_synth_event(se);
1330                 if (!ret) {
1331                         dyn_event_remove(&se->devent);
1332                         free_synth_event(se);
1333                 }
1334         }
1335
1336         return ret;
1337 }
1338
1339 /**
1340  * synth_event_delete - Delete a synthetic event
1341  * @event_name: The name of the new sythetic event
1342  *
1343  * Delete a synthetic event that was created with synth_event_create().
1344  *
1345  * Return: 0 if successful, error otherwise.
1346  */
1347 int synth_event_delete(const char *event_name)
1348 {
1349         struct synth_event *se = NULL;
1350         struct module *mod = NULL;
1351         int ret = -ENOENT;
1352
1353         mutex_lock(&event_mutex);
1354         se = find_synth_event(event_name);
1355         if (se) {
1356                 mod = se->mod;
1357                 ret = destroy_synth_event(se);
1358         }
1359         mutex_unlock(&event_mutex);
1360
1361         if (mod) {
1362                 mutex_lock(&trace_types_lock);
1363                 /*
1364                  * It is safest to reset the ring buffer if the module
1365                  * being unloaded registered any events that were
1366                  * used. The only worry is if a new module gets
1367                  * loaded, and takes on the same id as the events of
1368                  * this module. When printing out the buffer, traced
1369                  * events left over from this module may be passed to
1370                  * the new module events and unexpected results may
1371                  * occur.
1372                  */
1373                 tracing_reset_all_online_cpus();
1374                 mutex_unlock(&trace_types_lock);
1375         }
1376
1377         return ret;
1378 }
1379 EXPORT_SYMBOL_GPL(synth_event_delete);
1380
1381 static int create_or_delete_synth_event(int argc, char **argv)
1382 {
1383         const char *name = argv[0];
1384         int ret;
1385
1386         /* trace_run_command() ensures argc != 0 */
1387         if (name[0] == '!') {
1388                 ret = synth_event_delete(name + 1);
1389                 return ret;
1390         }
1391
1392         ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
1393         return ret == -ECANCELED ? -EINVAL : ret;
1394 }
1395
1396 static int synth_event_run_command(struct dynevent_cmd *cmd)
1397 {
1398         struct synth_event *se;
1399         int ret;
1400
1401         ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
1402         if (ret)
1403                 return ret;
1404
1405         se = find_synth_event(cmd->event_name);
1406         if (WARN_ON(!se))
1407                 return -ENOENT;
1408
1409         se->mod = cmd->private_data;
1410
1411         return ret;
1412 }
1413
1414 /**
1415  * synth_event_cmd_init - Initialize a synthetic event command object
1416  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1417  * @buf: A pointer to the buffer used to build the command
1418  * @maxlen: The length of the buffer passed in @buf
1419  *
1420  * Initialize a synthetic event command object.  Use this before
1421  * calling any of the other dyenvent_cmd functions.
1422  */
1423 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1424 {
1425         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1426                           synth_event_run_command);
1427 }
1428 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1429
1430 static inline int
1431 __synth_event_trace_init(struct trace_event_file *file,
1432                          struct synth_event_trace_state *trace_state)
1433 {
1434         int ret = 0;
1435
1436         memset(trace_state, '\0', sizeof(*trace_state));
1437
1438         /*
1439          * Normal event tracing doesn't get called at all unless the
1440          * ENABLED bit is set (which attaches the probe thus allowing
1441          * this code to be called, etc).  Because this is called
1442          * directly by the user, we don't have that but we still need
1443          * to honor not logging when disabled.  For the iterated
1444          * trace case, we save the enabed state upon start and just
1445          * ignore the following data calls.
1446          */
1447         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1448             trace_trigger_soft_disabled(file)) {
1449                 trace_state->disabled = true;
1450                 ret = -ENOENT;
1451                 goto out;
1452         }
1453
1454         trace_state->event = file->event_call->data;
1455 out:
1456         return ret;
1457 }
1458
1459 static inline int
1460 __synth_event_trace_start(struct trace_event_file *file,
1461                           struct synth_event_trace_state *trace_state,
1462                           int dynamic_fields_size)
1463 {
1464         int entry_size, fields_size = 0;
1465         int ret = 0;
1466
1467         fields_size = trace_state->event->n_u64 * sizeof(u64);
1468         fields_size += dynamic_fields_size;
1469
1470         /*
1471          * Avoid ring buffer recursion detection, as this event
1472          * is being performed within another event.
1473          */
1474         trace_state->buffer = file->tr->array_buffer.buffer;
1475         ring_buffer_nest_start(trace_state->buffer);
1476
1477         entry_size = sizeof(*trace_state->entry) + fields_size;
1478         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1479                                                         file,
1480                                                         entry_size);
1481         if (!trace_state->entry) {
1482                 ring_buffer_nest_end(trace_state->buffer);
1483                 ret = -EINVAL;
1484         }
1485
1486         return ret;
1487 }
1488
1489 static inline void
1490 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1491 {
1492         trace_event_buffer_commit(&trace_state->fbuffer);
1493
1494         ring_buffer_nest_end(trace_state->buffer);
1495 }
1496
1497 /**
1498  * synth_event_trace - Trace a synthetic event
1499  * @file: The trace_event_file representing the synthetic event
1500  * @n_vals: The number of values in vals
1501  * @args: Variable number of args containing the event values
1502  *
1503  * Trace a synthetic event using the values passed in the variable
1504  * argument list.
1505  *
1506  * The argument list should be a list 'n_vals' u64 values.  The number
1507  * of vals must match the number of field in the synthetic event, and
1508  * must be in the same order as the synthetic event fields.
1509  *
1510  * All vals should be cast to u64, and string vals are just pointers
1511  * to strings, cast to u64.  Strings will be copied into space
1512  * reserved in the event for the string, using these pointers.
1513  *
1514  * Return: 0 on success, err otherwise.
1515  */
1516 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1517 {
1518         unsigned int i, n_u64, len, data_size = 0;
1519         struct synth_event_trace_state state;
1520         va_list args;
1521         int ret;
1522
1523         ret = __synth_event_trace_init(file, &state);
1524         if (ret) {
1525                 if (ret == -ENOENT)
1526                         ret = 0; /* just disabled, not really an error */
1527                 return ret;
1528         }
1529
1530         if (state.event->n_dynamic_fields) {
1531                 va_start(args, n_vals);
1532
1533                 for (i = 0; i < state.event->n_fields; i++) {
1534                         u64 val = va_arg(args, u64);
1535
1536                         if (state.event->fields[i]->is_string &&
1537                             state.event->fields[i]->is_dynamic) {
1538                                 char *str_val = (char *)(long)val;
1539
1540                                 data_size += strlen(str_val) + 1;
1541                         }
1542                 }
1543
1544                 va_end(args);
1545         }
1546
1547         ret = __synth_event_trace_start(file, &state, data_size);
1548         if (ret)
1549                 return ret;
1550
1551         if (n_vals != state.event->n_fields) {
1552                 ret = -EINVAL;
1553                 goto out;
1554         }
1555
1556         data_size = 0;
1557
1558         va_start(args, n_vals);
1559         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1560                 u64 val;
1561
1562                 val = va_arg(args, u64);
1563
1564                 if (state.event->fields[i]->is_string) {
1565                         char *str_val = (char *)(long)val;
1566
1567                         len = trace_string(state.entry, state.event, str_val,
1568                                            state.event->fields[i]->is_dynamic,
1569                                            data_size, &n_u64);
1570                         data_size += len; /* only dynamic string increments */
1571                 } else {
1572                         struct synth_field *field = state.event->fields[i];
1573
1574                         switch (field->size) {
1575                         case 1:
1576                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1577                                 break;
1578
1579                         case 2:
1580                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1581                                 break;
1582
1583                         case 4:
1584                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1585                                 break;
1586
1587                         default:
1588                                 state.entry->fields[n_u64] = val;
1589                                 break;
1590                         }
1591                         n_u64++;
1592                 }
1593         }
1594         va_end(args);
1595 out:
1596         __synth_event_trace_end(&state);
1597
1598         return ret;
1599 }
1600 EXPORT_SYMBOL_GPL(synth_event_trace);
1601
1602 /**
1603  * synth_event_trace_array - Trace a synthetic event from an array
1604  * @file: The trace_event_file representing the synthetic event
1605  * @vals: Array of values
1606  * @n_vals: The number of values in vals
1607  *
1608  * Trace a synthetic event using the values passed in as 'vals'.
1609  *
1610  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1611  * vals must match the number of field in the synthetic event, and
1612  * must be in the same order as the synthetic event fields.
1613  *
1614  * All vals should be cast to u64, and string vals are just pointers
1615  * to strings, cast to u64.  Strings will be copied into space
1616  * reserved in the event for the string, using these pointers.
1617  *
1618  * Return: 0 on success, err otherwise.
1619  */
1620 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1621                             unsigned int n_vals)
1622 {
1623         unsigned int i, n_u64, field_pos, len, data_size = 0;
1624         struct synth_event_trace_state state;
1625         char *str_val;
1626         int ret;
1627
1628         ret = __synth_event_trace_init(file, &state);
1629         if (ret) {
1630                 if (ret == -ENOENT)
1631                         ret = 0; /* just disabled, not really an error */
1632                 return ret;
1633         }
1634
1635         if (state.event->n_dynamic_fields) {
1636                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1637                         field_pos = state.event->dynamic_fields[i]->field_pos;
1638                         str_val = (char *)(long)vals[field_pos];
1639                         len = strlen(str_val) + 1;
1640                         data_size += len;
1641                 }
1642         }
1643
1644         ret = __synth_event_trace_start(file, &state, data_size);
1645         if (ret)
1646                 return ret;
1647
1648         if (n_vals != state.event->n_fields) {
1649                 ret = -EINVAL;
1650                 goto out;
1651         }
1652
1653         data_size = 0;
1654
1655         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1656                 if (state.event->fields[i]->is_string) {
1657                         char *str_val = (char *)(long)vals[i];
1658
1659                         len = trace_string(state.entry, state.event, str_val,
1660                                            state.event->fields[i]->is_dynamic,
1661                                            data_size, &n_u64);
1662                         data_size += len; /* only dynamic string increments */
1663                 } else {
1664                         struct synth_field *field = state.event->fields[i];
1665                         u64 val = vals[i];
1666
1667                         switch (field->size) {
1668                         case 1:
1669                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1670                                 break;
1671
1672                         case 2:
1673                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1674                                 break;
1675
1676                         case 4:
1677                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1678                                 break;
1679
1680                         default:
1681                                 state.entry->fields[n_u64] = val;
1682                                 break;
1683                         }
1684                         n_u64++;
1685                 }
1686         }
1687 out:
1688         __synth_event_trace_end(&state);
1689
1690         return ret;
1691 }
1692 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1693
1694 /**
1695  * synth_event_trace_start - Start piecewise synthetic event trace
1696  * @file: The trace_event_file representing the synthetic event
1697  * @trace_state: A pointer to object tracking the piecewise trace state
1698  *
1699  * Start the trace of a synthetic event field-by-field rather than all
1700  * at once.
1701  *
1702  * This function 'opens' an event trace, which means space is reserved
1703  * for the event in the trace buffer, after which the event's
1704  * individual field values can be set through either
1705  * synth_event_add_next_val() or synth_event_add_val().
1706  *
1707  * A pointer to a trace_state object is passed in, which will keep
1708  * track of the current event trace state until the event trace is
1709  * closed (and the event finally traced) using
1710  * synth_event_trace_end().
1711  *
1712  * Note that synth_event_trace_end() must be called after all values
1713  * have been added for each event trace, regardless of whether adding
1714  * all field values succeeded or not.
1715  *
1716  * Note also that for a given event trace, all fields must be added
1717  * using either synth_event_add_next_val() or synth_event_add_val()
1718  * but not both together or interleaved.
1719  *
1720  * Return: 0 on success, err otherwise.
1721  */
1722 int synth_event_trace_start(struct trace_event_file *file,
1723                             struct synth_event_trace_state *trace_state)
1724 {
1725         int ret;
1726
1727         if (!trace_state)
1728                 return -EINVAL;
1729
1730         ret = __synth_event_trace_init(file, trace_state);
1731         if (ret) {
1732                 if (ret == -ENOENT)
1733                         ret = 0; /* just disabled, not really an error */
1734                 return ret;
1735         }
1736
1737         if (trace_state->event->n_dynamic_fields)
1738                 return -ENOTSUPP;
1739
1740         ret = __synth_event_trace_start(file, trace_state, 0);
1741
1742         return ret;
1743 }
1744 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1745
1746 static int __synth_event_add_val(const char *field_name, u64 val,
1747                                  struct synth_event_trace_state *trace_state)
1748 {
1749         struct synth_field *field = NULL;
1750         struct synth_trace_event *entry;
1751         struct synth_event *event;
1752         int i, ret = 0;
1753
1754         if (!trace_state) {
1755                 ret = -EINVAL;
1756                 goto out;
1757         }
1758
1759         /* can't mix add_next_synth_val() with add_synth_val() */
1760         if (field_name) {
1761                 if (trace_state->add_next) {
1762                         ret = -EINVAL;
1763                         goto out;
1764                 }
1765                 trace_state->add_name = true;
1766         } else {
1767                 if (trace_state->add_name) {
1768                         ret = -EINVAL;
1769                         goto out;
1770                 }
1771                 trace_state->add_next = true;
1772         }
1773
1774         if (trace_state->disabled)
1775                 goto out;
1776
1777         event = trace_state->event;
1778         if (trace_state->add_name) {
1779                 for (i = 0; i < event->n_fields; i++) {
1780                         field = event->fields[i];
1781                         if (strcmp(field->name, field_name) == 0)
1782                                 break;
1783                 }
1784                 if (!field) {
1785                         ret = -EINVAL;
1786                         goto out;
1787                 }
1788         } else {
1789                 if (trace_state->cur_field >= event->n_fields) {
1790                         ret = -EINVAL;
1791                         goto out;
1792                 }
1793                 field = event->fields[trace_state->cur_field++];
1794         }
1795
1796         entry = trace_state->entry;
1797         if (field->is_string) {
1798                 char *str_val = (char *)(long)val;
1799                 char *str_field;
1800
1801                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
1802                         ret = -EINVAL;
1803                         goto out;
1804                 }
1805
1806                 if (!str_val) {
1807                         ret = -EINVAL;
1808                         goto out;
1809                 }
1810
1811                 str_field = (char *)&entry->fields[field->offset];
1812                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
1813         } else {
1814                 switch (field->size) {
1815                 case 1:
1816                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
1817                         break;
1818
1819                 case 2:
1820                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
1821                         break;
1822
1823                 case 4:
1824                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
1825                         break;
1826
1827                 default:
1828                         trace_state->entry->fields[field->offset] = val;
1829                         break;
1830                 }
1831         }
1832  out:
1833         return ret;
1834 }
1835
1836 /**
1837  * synth_event_add_next_val - Add the next field's value to an open synth trace
1838  * @val: The value to set the next field to
1839  * @trace_state: A pointer to object tracking the piecewise trace state
1840  *
1841  * Set the value of the next field in an event that's been opened by
1842  * synth_event_trace_start().
1843  *
1844  * The val param should be the value cast to u64.  If the value points
1845  * to a string, the val param should be a char * cast to u64.
1846  *
1847  * This function assumes all the fields in an event are to be set one
1848  * after another - successive calls to this function are made, one for
1849  * each field, in the order of the fields in the event, until all
1850  * fields have been set.  If you'd rather set each field individually
1851  * without regard to ordering, synth_event_add_val() can be used
1852  * instead.
1853  *
1854  * Note however that synth_event_add_next_val() and
1855  * synth_event_add_val() can't be intermixed for a given event trace -
1856  * one or the other but not both can be used at the same time.
1857  *
1858  * Note also that synth_event_trace_end() must be called after all
1859  * values have been added for each event trace, regardless of whether
1860  * adding all field values succeeded or not.
1861  *
1862  * Return: 0 on success, err otherwise.
1863  */
1864 int synth_event_add_next_val(u64 val,
1865                              struct synth_event_trace_state *trace_state)
1866 {
1867         return __synth_event_add_val(NULL, val, trace_state);
1868 }
1869 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
1870
1871 /**
1872  * synth_event_add_val - Add a named field's value to an open synth trace
1873  * @field_name: The name of the synthetic event field value to set
1874  * @val: The value to set the next field to
1875  * @trace_state: A pointer to object tracking the piecewise trace state
1876  *
1877  * Set the value of the named field in an event that's been opened by
1878  * synth_event_trace_start().
1879  *
1880  * The val param should be the value cast to u64.  If the value points
1881  * to a string, the val param should be a char * cast to u64.
1882  *
1883  * This function looks up the field name, and if found, sets the field
1884  * to the specified value.  This lookup makes this function more
1885  * expensive than synth_event_add_next_val(), so use that or the
1886  * none-piecewise synth_event_trace() instead if efficiency is more
1887  * important.
1888  *
1889  * Note however that synth_event_add_next_val() and
1890  * synth_event_add_val() can't be intermixed for a given event trace -
1891  * one or the other but not both can be used at the same time.
1892  *
1893  * Note also that synth_event_trace_end() must be called after all
1894  * values have been added for each event trace, regardless of whether
1895  * adding all field values succeeded or not.
1896  *
1897  * Return: 0 on success, err otherwise.
1898  */
1899 int synth_event_add_val(const char *field_name, u64 val,
1900                         struct synth_event_trace_state *trace_state)
1901 {
1902         return __synth_event_add_val(field_name, val, trace_state);
1903 }
1904 EXPORT_SYMBOL_GPL(synth_event_add_val);
1905
1906 /**
1907  * synth_event_trace_end - End piecewise synthetic event trace
1908  * @trace_state: A pointer to object tracking the piecewise trace state
1909  *
1910  * End the trace of a synthetic event opened by
1911  * synth_event_trace__start().
1912  *
1913  * This function 'closes' an event trace, which basically means that
1914  * it commits the reserved event and cleans up other loose ends.
1915  *
1916  * A pointer to a trace_state object is passed in, which will keep
1917  * track of the current event trace state opened with
1918  * synth_event_trace_start().
1919  *
1920  * Note that this function must be called after all values have been
1921  * added for each event trace, regardless of whether adding all field
1922  * values succeeded or not.
1923  *
1924  * Return: 0 on success, err otherwise.
1925  */
1926 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
1927 {
1928         if (!trace_state)
1929                 return -EINVAL;
1930
1931         __synth_event_trace_end(trace_state);
1932
1933         return 0;
1934 }
1935 EXPORT_SYMBOL_GPL(synth_event_trace_end);
1936
1937 static int create_synth_event(int argc, const char **argv)
1938 {
1939         const char *name = argv[0];
1940         int len;
1941
1942         if (name[0] != 's' || name[1] != ':')
1943                 return -ECANCELED;
1944         name += 2;
1945
1946         /* This interface accepts group name prefix */
1947         if (strchr(name, '/')) {
1948                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
1949                 if (len == 0)
1950                         return -EINVAL;
1951                 name += len;
1952         }
1953         return __create_synth_event(argc - 1, name, argv + 1);
1954 }
1955
1956 static int synth_event_release(struct dyn_event *ev)
1957 {
1958         struct synth_event *event = to_synth_event(ev);
1959         int ret;
1960
1961         if (event->ref)
1962                 return -EBUSY;
1963
1964         ret = unregister_synth_event(event);
1965         if (ret)
1966                 return ret;
1967
1968         dyn_event_remove(ev);
1969         free_synth_event(event);
1970         return 0;
1971 }
1972
1973 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
1974 {
1975         struct synth_field *field;
1976         unsigned int i;
1977         char *type, *t;
1978
1979         seq_printf(m, "%s\t", event->name);
1980
1981         for (i = 0; i < event->n_fields; i++) {
1982                 field = event->fields[i];
1983
1984                 type = field->type;
1985                 t = strstr(type, "__data_loc");
1986                 if (t) { /* __data_loc belongs in format but not event desc */
1987                         t += sizeof("__data_loc");
1988                         type = t;
1989                 }
1990
1991                 /* parameter values */
1992                 seq_printf(m, "%s %s%s", type, field->name,
1993                            i == event->n_fields - 1 ? "" : "; ");
1994         }
1995
1996         seq_putc(m, '\n');
1997
1998         return 0;
1999 }
2000
2001 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2002 {
2003         struct synth_event *event = to_synth_event(ev);
2004
2005         seq_printf(m, "s:%s/", event->class.system);
2006
2007         return __synth_event_show(m, event);
2008 }
2009
2010 static int synth_events_seq_show(struct seq_file *m, void *v)
2011 {
2012         struct dyn_event *ev = v;
2013
2014         if (!is_synth_event(ev))
2015                 return 0;
2016
2017         return __synth_event_show(m, to_synth_event(ev));
2018 }
2019
2020 static const struct seq_operations synth_events_seq_op = {
2021         .start  = dyn_event_seq_start,
2022         .next   = dyn_event_seq_next,
2023         .stop   = dyn_event_seq_stop,
2024         .show   = synth_events_seq_show,
2025 };
2026
2027 static int synth_events_open(struct inode *inode, struct file *file)
2028 {
2029         int ret;
2030
2031         ret = security_locked_down(LOCKDOWN_TRACEFS);
2032         if (ret)
2033                 return ret;
2034
2035         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2036                 ret = dyn_events_release_all(&synth_event_ops);
2037                 if (ret < 0)
2038                         return ret;
2039         }
2040
2041         return seq_open(file, &synth_events_seq_op);
2042 }
2043
2044 static ssize_t synth_events_write(struct file *file,
2045                                   const char __user *buffer,
2046                                   size_t count, loff_t *ppos)
2047 {
2048         return trace_parse_run_command(file, buffer, count, ppos,
2049                                        create_or_delete_synth_event);
2050 }
2051
2052 static const struct file_operations synth_events_fops = {
2053         .open           = synth_events_open,
2054         .write          = synth_events_write,
2055         .read           = seq_read,
2056         .llseek         = seq_lseek,
2057         .release        = seq_release,
2058 };
2059
2060 /*
2061  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2062  * events in postcore_initcall without tracefs.
2063  */
2064 static __init int trace_events_synth_init_early(void)
2065 {
2066         int err = 0;
2067
2068         err = dyn_event_register(&synth_event_ops);
2069         if (err)
2070                 pr_warn("Could not register synth_event_ops\n");
2071
2072         return err;
2073 }
2074 core_initcall(trace_events_synth_init_early);
2075
2076 static __init int trace_events_synth_init(void)
2077 {
2078         struct dentry *entry = NULL;
2079         int err = 0;
2080         err = tracing_init_dentry();
2081         if (err)
2082                 goto err;
2083
2084         entry = tracefs_create_file("synthetic_events", 0644, NULL,
2085                                     NULL, &synth_events_fops);
2086         if (!entry) {
2087                 err = -ENODEV;
2088                 goto err;
2089         }
2090
2091         return err;
2092  err:
2093         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2094
2095         return err;
2096 }
2097
2098 fs_initcall(trace_events_synth_init);