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 = -ENOMEM;
 588         struct seq_buf s;
 589         ssize_t size;
 590
 591         if (field_type[0] == ';')
 592                 field_type++;
 593
 594         if (!strcmp(field_type, "unsigned")) {
 595                 if (argc < 3) {
 596                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 597                         return ERR_PTR(-EINVAL);
 598                 }
 599                 prefix = "unsigned ";
 600                 field_type = argv[1];
 601                 field_name = argv[2];
 602                 *consumed = 3;
 603         } else {
 604                 field_name = argv[1];
 605                 *consumed = 2;
 606         }
 607
 608         field = kzalloc(sizeof(*field), GFP_KERNEL);
 609         if (!field)
 610                 return ERR_PTR(-ENOMEM);
 611
 612         len = strlen(field_name);
 613         array = strchr(field_name, '[');
 614         if (array)
 615                 len -= strlen(array);
 616         else if (field_name[len - 1] == ';')
 617                 len--;
 618
 619         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 620         if (!field->name)
 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                 len += strlen(array);
 635
 636         if (prefix)
 637                 len += strlen(prefix);
 638
 639         field->type = kzalloc(len, GFP_KERNEL);
 640         if (!field->type)
 641                 goto free;
 642
 643         seq_buf_init(&s, field->type, len);
 644         if (prefix)
 645                 seq_buf_puts(&s, prefix);
 646         seq_buf_puts(&s, field_type);
 647         if (array) {
 648                 seq_buf_puts(&s, array);
 649                 if (s.buffer[s.len - 1] == ';')
 650                         s.len--;
 651         }
 652         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 653                 goto free;
 654
 655         s.buffer[s.len] = '\0';
 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                         len = sizeof("__data_loc ") + strlen(field->type) + 1;
 667                         type = kzalloc(len, GFP_KERNEL);
 668                         if (!type)
 669                                 goto free;
 670
 671                         seq_buf_init(&s, type, len);
 672                         seq_buf_puts(&s, "__data_loc ");
 673                         seq_buf_puts(&s, field->type);
 674
 675                         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 676                                 goto free;
 677                         s.buffer[s.len] = '\0';
 678
 679                         kfree(field->type);
 680                         field->type = type;
 681
 682                         field->is_dynamic = true;
 683                         size = sizeof(u64);
 684                 } else {
 685                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 686                         ret = -EINVAL;
 687                         goto free;
 688                 }
 689         }
 690         field->size = size;
 691
 692         if (synth_field_is_string(field->type))
 693                 field->is_string = true;
 694
 695         field->is_signed = synth_field_signed(field->type);
 696  out:
 697         return field;
 698  free:
 699         free_synth_field(field);
 700         field = ERR_PTR(ret);
 701         goto out;
 702 }
 703
 704 static void free_synth_tracepoint(struct tracepoint *tp)
 705 {
 706         if (!tp)
 707                 return;
 708
 709         kfree(tp->name);
 710         kfree(tp);
 711 }
 712
 713 static struct tracepoint *alloc_synth_tracepoint(char *name)
 714 {
 715         struct tracepoint *tp;
 716
 717         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 718         if (!tp)
 719                 return ERR_PTR(-ENOMEM);
 720
 721         tp->name = kstrdup(name, GFP_KERNEL);
 722         if (!tp->name) {
 723                 kfree(tp);
 724                 return ERR_PTR(-ENOMEM);
 725         }
 726
 727         return tp;
 728 }
 729
 730 struct synth_event *find_synth_event(const char *name)
 731 {
 732         struct dyn_event *pos;
 733         struct synth_event *event;
 734
 735         for_each_dyn_event(pos) {
 736                 if (!is_synth_event(pos))
 737                         continue;
 738                 event = to_synth_event(pos);
 739                 if (strcmp(event->name, name) == 0)
 740                         return event;
 741         }
 742
 743         return NULL;
 744 }
 745
 746 static struct trace_event_fields synth_event_fields_array[] = {
 747         { .type = TRACE_FUNCTION_TYPE,
 748           .define_fields = synth_event_define_fields },
 749         {}
 750 };
 751
 752 static int register_synth_event(struct synth_event *event)
 753 {
 754         struct trace_event_call *call = &event->call;
 755         int ret = 0;
 756
 757         event->call.class = &event->class;
 758         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 759         if (!event->class.system) {
 760                 ret = -ENOMEM;
 761                 goto out;
 762         }
 763
 764         event->tp = alloc_synth_tracepoint(event->name);
 765         if (IS_ERR(event->tp)) {
 766                 ret = PTR_ERR(event->tp);
 767                 event->tp = NULL;
 768                 goto out;
 769         }
 770
 771         INIT_LIST_HEAD(&call->class->fields);
 772         call->event.funcs = &synth_event_funcs;
 773         call->class->fields_array = synth_event_fields_array;
 774
 775         ret = register_trace_event(&call->event);
 776         if (!ret) {
 777                 ret = -ENODEV;
 778                 goto out;
 779         }
 780         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 781         call->class->reg = trace_event_reg;
 782         call->class->probe = trace_event_raw_event_synth;
 783         call->data = event;
 784         call->tp = event->tp;
 785
 786         ret = trace_add_event_call(call);
 787         if (ret) {
 788                 pr_warn("Failed to register synthetic event: %s\n",
 789                         trace_event_name(call));
 790                 goto err;
 791         }
 792
 793         ret = set_synth_event_print_fmt(call);
 794         if (ret < 0) {
 795                 trace_remove_event_call(call);
 796                 goto err;
 797         }
 798  out:
 799         return ret;
 800  err:
 801         unregister_trace_event(&call->event);
 802         goto out;
 803 }
 804
 805 static int unregister_synth_event(struct synth_event *event)
 806 {
 807         struct trace_event_call *call = &event->call;
 808         int ret;
 809
 810         ret = trace_remove_event_call(call);
 811
 812         return ret;
 813 }
 814
 815 static void free_synth_event(struct synth_event *event)
 816 {
 817         unsigned int i;
 818
 819         if (!event)
 820                 return;
 821
 822         for (i = 0; i < event->n_fields; i++)
 823                 free_synth_field(event->fields[i]);
 824
 825         kfree(event->fields);
 826         kfree(event->dynamic_fields);
 827         kfree(event->name);
 828         kfree(event->class.system);
 829         free_synth_tracepoint(event->tp);
 830         free_synth_event_print_fmt(&event->call);
 831         kfree(event);
 832 }
 833
 834 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 835                                              struct synth_field **fields)
 836 {
 837         unsigned int i, j, n_dynamic_fields = 0;
 838         struct synth_event *event;
 839
 840         event = kzalloc(sizeof(*event), GFP_KERNEL);
 841         if (!event) {
 842                 event = ERR_PTR(-ENOMEM);
 843                 goto out;
 844         }
 845
 846         event->name = kstrdup(name, GFP_KERNEL);
 847         if (!event->name) {
 848                 kfree(event);
 849                 event = ERR_PTR(-ENOMEM);
 850                 goto out;
 851         }
 852
 853         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 854         if (!event->fields) {
 855                 free_synth_event(event);
 856                 event = ERR_PTR(-ENOMEM);
 857                 goto out;
 858         }
 859
 860         for (i = 0; i < n_fields; i++)
 861                 if (fields[i]->is_dynamic)
 862                         n_dynamic_fields++;
 863
 864         if (n_dynamic_fields) {
 865                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 866                                                 sizeof(*event->dynamic_fields),
 867                                                 GFP_KERNEL);
 868                 if (!event->dynamic_fields) {
 869                         free_synth_event(event);
 870                         event = ERR_PTR(-ENOMEM);
 871                         goto out;
 872                 }
 873         }
 874
 875         dyn_event_init(&event->devent, &synth_event_ops);
 876
 877         for (i = 0, j = 0; i < n_fields; i++) {
 878                 event->fields[i] = fields[i];
 879
 880                 if (fields[i]->is_dynamic) {
 881                         event->dynamic_fields[j] = fields[i];
 882                         event->dynamic_fields[j]->field_pos = i;
 883                         event->dynamic_fields[j++] = fields[i];
 884                         event->n_dynamic_fields++;
 885                 }
 886         }
 887         event->n_fields = n_fields;
 888  out:
 889         return event;
 890 }
 891
 892 static int synth_event_check_arg_fn(void *data)
 893 {
 894         struct dynevent_arg_pair *arg_pair = data;
 895         int size;
 896
 897         size = synth_field_size((char *)arg_pair->lhs);
 898         if (size == 0) {
 899                 if (strstr((char *)arg_pair->lhs, "["))
 900                         return 0;
 901         }
 902
 903         return size ? 0 : -EINVAL;
 904 }
 905
 906 /**
 907  * synth_event_add_field - Add a new field to a synthetic event cmd
 908  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 909  * @type: The type of the new field to add
 910  * @name: The name of the new field to add
 911  *
 912  * Add a new field to a synthetic event cmd object.  Field ordering is in
 913  * the same order the fields are added.
 914  *
 915  * See synth_field_size() for available types. If field_name contains
 916  * [n] the field is considered to be an array.
 917  *
 918  * Return: 0 if successful, error otherwise.
 919  */
 920 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
 921                           const char *name)
 922 {
 923         struct dynevent_arg_pair arg_pair;
 924         int ret;
 925
 926         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 927                 return -EINVAL;
 928
 929         if (!type || !name)
 930                 return -EINVAL;
 931
 932         dynevent_arg_pair_init(&arg_pair, 0, ';');
 933
 934         arg_pair.lhs = type;
 935         arg_pair.rhs = name;
 936
 937         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
 938         if (ret)
 939                 return ret;
 940
 941         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 942                 ret = -EINVAL;
 943
 944         return ret;
 945 }
 946 EXPORT_SYMBOL_GPL(synth_event_add_field);
 947
 948 /**
 949  * synth_event_add_field_str - Add a new field to a synthetic event cmd
 950  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 951  * @type_name: The type and name of the new field to add, as a single string
 952  *
 953  * Add a new field to a synthetic event cmd object, as a single
 954  * string.  The @type_name string is expected to be of the form 'type
 955  * name', which will be appended by ';'.  No sanity checking is done -
 956  * what's passed in is assumed to already be well-formed.  Field
 957  * ordering is in the same order the fields are added.
 958  *
 959  * See synth_field_size() for available types. If field_name contains
 960  * [n] the field is considered to be an array.
 961  *
 962  * Return: 0 if successful, error otherwise.
 963  */
 964 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
 965 {
 966         struct dynevent_arg arg;
 967         int ret;
 968
 969         if (cmd->type != DYNEVENT_TYPE_SYNTH)
 970                 return -EINVAL;
 971
 972         if (!type_name)
 973                 return -EINVAL;
 974
 975         dynevent_arg_init(&arg, ';');
 976
 977         arg.str = type_name;
 978
 979         ret = dynevent_arg_add(cmd, &arg, NULL);
 980         if (ret)
 981                 return ret;
 982
 983         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 984                 ret = -EINVAL;
 985
 986         return ret;
 987 }
 988 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
 989
 990 /**
 991  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
 992  * @cmd: A pointer to the dynevent_cmd struct representing the new event
 993  * @fields: An array of type/name field descriptions
 994  * @n_fields: The number of field descriptions contained in the fields array
 995  *
 996  * Add a new set of fields to a synthetic event cmd object.  The event
 997  * fields that will be defined for the event should be passed in as an
 998  * array of struct synth_field_desc, and the number of elements in the
 999  * array passed in as n_fields.  Field ordering will retain the
1000  * ordering given in the fields array.
1001  *
1002  * See synth_field_size() for available types. If field_name contains
1003  * [n] the field is considered to be an array.
1004  *
1005  * Return: 0 if successful, error otherwise.
1006  */
1007 int synth_event_add_fields(struct dynevent_cmd *cmd,
1008                            struct synth_field_desc *fields,
1009                            unsigned int n_fields)
1010 {
1011         unsigned int i;
1012         int ret = 0;
1013
1014         for (i = 0; i < n_fields; i++) {
1015                 if (fields[i].type == NULL || fields[i].name == NULL) {
1016                         ret = -EINVAL;
1017                         break;
1018                 }
1019
1020                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1021                 if (ret)
1022                         break;
1023         }
1024
1025         return ret;
1026 }
1027 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1028
1029 /**
1030  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1031  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1032  * @name: The name of the synthetic event
1033  * @mod: The module creating the event, NULL if not created from a module
1034  * @args: Variable number of arg (pairs), one pair for each field
1035  *
1036  * NOTE: Users normally won't want to call this function directly, but
1037  * rather use the synth_event_gen_cmd_start() wrapper, which
1038  * automatically adds a NULL to the end of the arg list.  If this
1039  * function is used directly, make sure the last arg in the variable
1040  * arg list is NULL.
1041  *
1042  * Generate a synthetic event command to be executed by
1043  * synth_event_gen_cmd_end().  This function can be used to generate
1044  * the complete command or only the first part of it; in the latter
1045  * case, synth_event_add_field(), synth_event_add_field_str(), or
1046  * synth_event_add_fields() can be used to add more fields following
1047  * this.
1048  *
1049  * There should be an even number variable args, each pair consisting
1050  * of a type followed by a field name.
1051  *
1052  * See synth_field_size() for available types. If field_name contains
1053  * [n] the field is considered to be an array.
1054  *
1055  * Return: 0 if successful, error otherwise.
1056  */
1057 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1058                                 struct module *mod, ...)
1059 {
1060         struct dynevent_arg arg;
1061         va_list args;
1062         int ret;
1063
1064         cmd->event_name = name;
1065         cmd->private_data = mod;
1066
1067         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1068                 return -EINVAL;
1069
1070         dynevent_arg_init(&arg, 0);
1071         arg.str = name;
1072         ret = dynevent_arg_add(cmd, &arg, NULL);
1073         if (ret)
1074                 return ret;
1075
1076         va_start(args, mod);
1077         for (;;) {
1078                 const char *type, *name;
1079
1080                 type = va_arg(args, const char *);
1081                 if (!type)
1082                         break;
1083                 name = va_arg(args, const char *);
1084                 if (!name)
1085                         break;
1086
1087                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1088                         ret = -EINVAL;
1089                         break;
1090                 }
1091
1092                 ret = synth_event_add_field(cmd, type, name);
1093                 if (ret)
1094                         break;
1095         }
1096         va_end(args);
1097
1098         return ret;
1099 }
1100 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1101
1102 /**
1103  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1104  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1105  * @name: The name of the synthetic event
1106  * @fields: An array of type/name field descriptions
1107  * @n_fields: The number of field descriptions contained in the fields array
1108  *
1109  * Generate a synthetic event command to be executed by
1110  * synth_event_gen_cmd_end().  This function can be used to generate
1111  * the complete command or only the first part of it; in the latter
1112  * case, synth_event_add_field(), synth_event_add_field_str(), or
1113  * synth_event_add_fields() can be used to add more fields following
1114  * this.
1115  *
1116  * The event fields that will be defined for the event should be
1117  * passed in as an array of struct synth_field_desc, and the number of
1118  * elements in the array passed in as n_fields.  Field ordering will
1119  * retain the ordering given in the fields array.
1120  *
1121  * See synth_field_size() for available types. If field_name contains
1122  * [n] the field is considered to be an array.
1123  *
1124  * Return: 0 if successful, error otherwise.
1125  */
1126 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1127                                     struct module *mod,
1128                                     struct synth_field_desc *fields,
1129                                     unsigned int n_fields)
1130 {
1131         struct dynevent_arg arg;
1132         unsigned int i;
1133         int ret = 0;
1134
1135         cmd->event_name = name;
1136         cmd->private_data = mod;
1137
1138         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1139                 return -EINVAL;
1140
1141         if (n_fields > SYNTH_FIELDS_MAX)
1142                 return -EINVAL;
1143
1144         dynevent_arg_init(&arg, 0);
1145         arg.str = name;
1146         ret = dynevent_arg_add(cmd, &arg, NULL);
1147         if (ret)
1148                 return ret;
1149
1150         for (i = 0; i < n_fields; i++) {
1151                 if (fields[i].type == NULL || fields[i].name == NULL)
1152                         return -EINVAL;
1153
1154                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1155                 if (ret)
1156                         break;
1157         }
1158
1159         return ret;
1160 }
1161 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1162
1163 static int save_cmdstr(int argc, const char *name, const char **argv)
1164 {
1165         struct seq_buf s;
1166         char *buf;
1167         int i;
1168
1169         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1170         if (!buf)
1171                 return -ENOMEM;
1172
1173         seq_buf_init(&s, buf, MAX_DYNEVENT_CMD_LEN);
1174
1175         seq_buf_puts(&s, name);
1176
1177         for (i = 0; i < argc; i++) {
1178                 seq_buf_putc(&s, ' ');
1179                 seq_buf_puts(&s, argv[i]);
1180         }
1181
1182         if (!seq_buf_buffer_left(&s)) {
1183                 synth_err(SYNTH_ERR_CMD_TOO_LONG, 0);
1184                 kfree(buf);
1185                 return -EINVAL;
1186         }
1187         buf[s.len] = 0;
1188         last_cmd_set(buf);
1189
1190         kfree(buf);
1191         return 0;
1192 }
1193
1194 static int __create_synth_event(int argc, const char *name, const char **argv)
1195 {
1196         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1197         struct synth_event *event = NULL;
1198         int i, consumed = 0, n_fields = 0, ret = 0;
1199
1200         ret = save_cmdstr(argc, name, argv);
1201         if (ret)
1202                 return ret;
1203
1204         /*
1205          * Argument syntax:
1206          *  - Add synthetic event: <event_name> field[;field] ...
1207          *  - Remove synthetic event: !<event_name> field[;field] ...
1208          *      where 'field' = type field_name
1209          */
1210
1211         if (name[0] == '\0' || argc < 1) {
1212                 synth_err(SYNTH_ERR_CMD_INCOMPLETE, 0);
1213                 return -EINVAL;
1214         }
1215
1216         mutex_lock(&event_mutex);
1217
1218         if (!is_good_name(name)) {
1219                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1220                 ret = -EINVAL;
1221                 goto out;
1222         }
1223
1224         event = find_synth_event(name);
1225         if (event) {
1226                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1227                 ret = -EEXIST;
1228                 goto out;
1229         }
1230
1231         for (i = 0; i < argc - 1; i++) {
1232                 if (strcmp(argv[i], ";") == 0)
1233                         continue;
1234                 if (n_fields == SYNTH_FIELDS_MAX) {
1235                         synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1236                         ret = -EINVAL;
1237                         goto err;
1238                 }
1239
1240                 field = parse_synth_field(argc - i, &argv[i], &consumed);
1241                 if (IS_ERR(field)) {
1242                         ret = PTR_ERR(field);
1243                         goto err;
1244                 }
1245                 fields[n_fields++] = field;
1246                 i += consumed - 1;
1247         }
1248
1249         if (i < argc && strcmp(argv[i], ";") != 0) {
1250                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(argv[i]));
1251                 ret = -EINVAL;
1252                 goto err;
1253         }
1254
1255         event = alloc_synth_event(name, n_fields, fields);
1256         if (IS_ERR(event)) {
1257                 ret = PTR_ERR(event);
1258                 event = NULL;
1259                 goto err;
1260         }
1261         ret = register_synth_event(event);
1262         if (!ret)
1263                 dyn_event_add(&event->devent);
1264         else
1265                 free_synth_event(event);
1266  out:
1267         mutex_unlock(&event_mutex);
1268
1269         return ret;
1270  err:
1271         for (i = 0; i < n_fields; i++)
1272                 free_synth_field(fields[i]);
1273
1274         goto out;
1275 }
1276
1277 /**
1278  * synth_event_create - Create a new synthetic event
1279  * @name: The name of the new synthetic event
1280  * @fields: An array of type/name field descriptions
1281  * @n_fields: The number of field descriptions contained in the fields array
1282  * @mod: The module creating the event, NULL if not created from a module
1283  *
1284  * Create a new synthetic event with the given name under the
1285  * trace/events/synthetic/ directory.  The event fields that will be
1286  * defined for the event should be passed in as an array of struct
1287  * synth_field_desc, and the number elements in the array passed in as
1288  * n_fields. Field ordering will retain the ordering given in the
1289  * fields array.
1290  *
1291  * If the new synthetic event is being created from a module, the mod
1292  * param must be non-NULL.  This will ensure that the trace buffer
1293  * won't contain unreadable events.
1294  *
1295  * The new synth event should be deleted using synth_event_delete()
1296  * function.  The new synthetic event can be generated from modules or
1297  * other kernel code using trace_synth_event() and related functions.
1298  *
1299  * Return: 0 if successful, error otherwise.
1300  */
1301 int synth_event_create(const char *name, struct synth_field_desc *fields,
1302                        unsigned int n_fields, struct module *mod)
1303 {
1304         struct dynevent_cmd cmd;
1305         char *buf;
1306         int ret;
1307
1308         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1309         if (!buf)
1310                 return -ENOMEM;
1311
1312         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1313
1314         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1315                                               fields, n_fields);
1316         if (ret)
1317                 goto out;
1318
1319         ret = synth_event_gen_cmd_end(&cmd);
1320  out:
1321         kfree(buf);
1322
1323         return ret;
1324 }
1325 EXPORT_SYMBOL_GPL(synth_event_create);
1326
1327 static int destroy_synth_event(struct synth_event *se)
1328 {
1329         int ret;
1330
1331         if (se->ref)
1332                 ret = -EBUSY;
1333         else {
1334                 ret = unregister_synth_event(se);
1335                 if (!ret) {
1336                         dyn_event_remove(&se->devent);
1337                         free_synth_event(se);
1338                 }
1339         }
1340
1341         return ret;
1342 }
1343
1344 /**
1345  * synth_event_delete - Delete a synthetic event
1346  * @event_name: The name of the new sythetic event
1347  *
1348  * Delete a synthetic event that was created with synth_event_create().
1349  *
1350  * Return: 0 if successful, error otherwise.
1351  */
1352 int synth_event_delete(const char *event_name)
1353 {
1354         struct synth_event *se = NULL;
1355         struct module *mod = NULL;
1356         int ret = -ENOENT;
1357
1358         mutex_lock(&event_mutex);
1359         se = find_synth_event(event_name);
1360         if (se) {
1361                 mod = se->mod;
1362                 ret = destroy_synth_event(se);
1363         }
1364         mutex_unlock(&event_mutex);
1365
1366         if (mod) {
1367                 mutex_lock(&trace_types_lock);
1368                 /*
1369                  * It is safest to reset the ring buffer if the module
1370                  * being unloaded registered any events that were
1371                  * used. The only worry is if a new module gets
1372                  * loaded, and takes on the same id as the events of
1373                  * this module. When printing out the buffer, traced
1374                  * events left over from this module may be passed to
1375                  * the new module events and unexpected results may
1376                  * occur.
1377                  */
1378                 tracing_reset_all_online_cpus();
1379                 mutex_unlock(&trace_types_lock);
1380         }
1381
1382         return ret;
1383 }
1384 EXPORT_SYMBOL_GPL(synth_event_delete);
1385
1386 static int create_or_delete_synth_event(int argc, char **argv)
1387 {
1388         const char *name = argv[0];
1389         int ret;
1390
1391         /* trace_run_command() ensures argc != 0 */
1392         if (name[0] == '!') {
1393                 ret = synth_event_delete(name + 1);
1394                 return ret;
1395         }
1396
1397         ret = __create_synth_event(argc - 1, name, (const char **)argv + 1);
1398         return ret == -ECANCELED ? -EINVAL : ret;
1399 }
1400
1401 static int synth_event_run_command(struct dynevent_cmd *cmd)
1402 {
1403         struct synth_event *se;
1404         int ret;
1405
1406         ret = trace_run_command(cmd->seq.buffer, create_or_delete_synth_event);
1407         if (ret)
1408                 return ret;
1409
1410         se = find_synth_event(cmd->event_name);
1411         if (WARN_ON(!se))
1412                 return -ENOENT;
1413
1414         se->mod = cmd->private_data;
1415
1416         return ret;
1417 }
1418
1419 /**
1420  * synth_event_cmd_init - Initialize a synthetic event command object
1421  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1422  * @buf: A pointer to the buffer used to build the command
1423  * @maxlen: The length of the buffer passed in @buf
1424  *
1425  * Initialize a synthetic event command object.  Use this before
1426  * calling any of the other dyenvent_cmd functions.
1427  */
1428 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1429 {
1430         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1431                           synth_event_run_command);
1432 }
1433 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1434
1435 static inline int
1436 __synth_event_trace_init(struct trace_event_file *file,
1437                          struct synth_event_trace_state *trace_state)
1438 {
1439         int ret = 0;
1440
1441         memset(trace_state, '\0', sizeof(*trace_state));
1442
1443         /*
1444          * Normal event tracing doesn't get called at all unless the
1445          * ENABLED bit is set (which attaches the probe thus allowing
1446          * this code to be called, etc).  Because this is called
1447          * directly by the user, we don't have that but we still need
1448          * to honor not logging when disabled.  For the iterated
1449          * trace case, we save the enabled state upon start and just
1450          * ignore the following data calls.
1451          */
1452         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1453             trace_trigger_soft_disabled(file)) {
1454                 trace_state->disabled = true;
1455                 ret = -ENOENT;
1456                 goto out;
1457         }
1458
1459         trace_state->event = file->event_call->data;
1460 out:
1461         return ret;
1462 }
1463
1464 static inline int
1465 __synth_event_trace_start(struct trace_event_file *file,
1466                           struct synth_event_trace_state *trace_state,
1467                           int dynamic_fields_size)
1468 {
1469         int entry_size, fields_size = 0;
1470         int ret = 0;
1471
1472         fields_size = trace_state->event->n_u64 * sizeof(u64);
1473         fields_size += dynamic_fields_size;
1474
1475         /*
1476          * Avoid ring buffer recursion detection, as this event
1477          * is being performed within another event.
1478          */
1479         trace_state->buffer = file->tr->array_buffer.buffer;
1480         ring_buffer_nest_start(trace_state->buffer);
1481
1482         entry_size = sizeof(*trace_state->entry) + fields_size;
1483         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1484                                                         file,
1485                                                         entry_size);
1486         if (!trace_state->entry) {
1487                 ring_buffer_nest_end(trace_state->buffer);
1488                 ret = -EINVAL;
1489         }
1490
1491         return ret;
1492 }
1493
1494 static inline void
1495 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1496 {
1497         trace_event_buffer_commit(&trace_state->fbuffer);
1498
1499         ring_buffer_nest_end(trace_state->buffer);
1500 }
1501
1502 /**
1503  * synth_event_trace - Trace a synthetic event
1504  * @file: The trace_event_file representing the synthetic event
1505  * @n_vals: The number of values in vals
1506  * @args: Variable number of args containing the event values
1507  *
1508  * Trace a synthetic event using the values passed in the variable
1509  * argument list.
1510  *
1511  * The argument list should be a list 'n_vals' u64 values.  The number
1512  * of vals must match the number of field in the synthetic event, and
1513  * must be in the same order as the synthetic event fields.
1514  *
1515  * All vals should be cast to u64, and string vals are just pointers
1516  * to strings, cast to u64.  Strings will be copied into space
1517  * reserved in the event for the string, using these pointers.
1518  *
1519  * Return: 0 on success, err otherwise.
1520  */
1521 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1522 {
1523         unsigned int i, n_u64, len, data_size = 0;
1524         struct synth_event_trace_state state;
1525         va_list args;
1526         int ret;
1527
1528         ret = __synth_event_trace_init(file, &state);
1529         if (ret) {
1530                 if (ret == -ENOENT)
1531                         ret = 0; /* just disabled, not really an error */
1532                 return ret;
1533         }
1534
1535         if (state.event->n_dynamic_fields) {
1536                 va_start(args, n_vals);
1537
1538                 for (i = 0; i < state.event->n_fields; i++) {
1539                         u64 val = va_arg(args, u64);
1540
1541                         if (state.event->fields[i]->is_string &&
1542                             state.event->fields[i]->is_dynamic) {
1543                                 char *str_val = (char *)(long)val;
1544
1545                                 data_size += strlen(str_val) + 1;
1546                         }
1547                 }
1548
1549                 va_end(args);
1550         }
1551
1552         ret = __synth_event_trace_start(file, &state, data_size);
1553         if (ret)
1554                 return ret;
1555
1556         if (n_vals != state.event->n_fields) {
1557                 ret = -EINVAL;
1558                 goto out;
1559         }
1560
1561         data_size = 0;
1562
1563         va_start(args, n_vals);
1564         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1565                 u64 val;
1566
1567                 val = va_arg(args, u64);
1568
1569                 if (state.event->fields[i]->is_string) {
1570                         char *str_val = (char *)(long)val;
1571
1572                         len = trace_string(state.entry, state.event, str_val,
1573                                            state.event->fields[i]->is_dynamic,
1574                                            data_size, &n_u64);
1575                         data_size += len; /* only dynamic string increments */
1576                 } else {
1577                         struct synth_field *field = state.event->fields[i];
1578
1579                         switch (field->size) {
1580                         case 1:
1581                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1582                                 break;
1583
1584                         case 2:
1585                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1586                                 break;
1587
1588                         case 4:
1589                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1590                                 break;
1591
1592                         default:
1593                                 state.entry->fields[n_u64] = val;
1594                                 break;
1595                         }
1596                         n_u64++;
1597                 }
1598         }
1599         va_end(args);
1600 out:
1601         __synth_event_trace_end(&state);
1602
1603         return ret;
1604 }
1605 EXPORT_SYMBOL_GPL(synth_event_trace);
1606
1607 /**
1608  * synth_event_trace_array - Trace a synthetic event from an array
1609  * @file: The trace_event_file representing the synthetic event
1610  * @vals: Array of values
1611  * @n_vals: The number of values in vals
1612  *
1613  * Trace a synthetic event using the values passed in as 'vals'.
1614  *
1615  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1616  * vals must match the number of field in the synthetic event, and
1617  * must be in the same order as the synthetic event fields.
1618  *
1619  * All vals should be cast to u64, and string vals are just pointers
1620  * to strings, cast to u64.  Strings will be copied into space
1621  * reserved in the event for the string, using these pointers.
1622  *
1623  * Return: 0 on success, err otherwise.
1624  */
1625 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1626                             unsigned int n_vals)
1627 {
1628         unsigned int i, n_u64, field_pos, len, data_size = 0;
1629         struct synth_event_trace_state state;
1630         char *str_val;
1631         int ret;
1632
1633         ret = __synth_event_trace_init(file, &state);
1634         if (ret) {
1635                 if (ret == -ENOENT)
1636                         ret = 0; /* just disabled, not really an error */
1637                 return ret;
1638         }
1639
1640         if (state.event->n_dynamic_fields) {
1641                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1642                         field_pos = state.event->dynamic_fields[i]->field_pos;
1643                         str_val = (char *)(long)vals[field_pos];
1644                         len = strlen(str_val) + 1;
1645                         data_size += len;
1646                 }
1647         }
1648
1649         ret = __synth_event_trace_start(file, &state, data_size);
1650         if (ret)
1651                 return ret;
1652
1653         if (n_vals != state.event->n_fields) {
1654                 ret = -EINVAL;
1655                 goto out;
1656         }
1657
1658         data_size = 0;
1659
1660         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1661                 if (state.event->fields[i]->is_string) {
1662                         char *str_val = (char *)(long)vals[i];
1663
1664                         len = trace_string(state.entry, state.event, str_val,
1665                                            state.event->fields[i]->is_dynamic,
1666                                            data_size, &n_u64);
1667                         data_size += len; /* only dynamic string increments */
1668                 } else {
1669                         struct synth_field *field = state.event->fields[i];
1670                         u64 val = vals[i];
1671
1672                         switch (field->size) {
1673                         case 1:
1674                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1675                                 break;
1676
1677                         case 2:
1678                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1679                                 break;
1680
1681                         case 4:
1682                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1683                                 break;
1684
1685                         default:
1686                                 state.entry->fields[n_u64] = val;
1687                                 break;
1688                         }
1689                         n_u64++;
1690                 }
1691         }
1692 out:
1693         __synth_event_trace_end(&state);
1694
1695         return ret;
1696 }
1697 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1698
1699 /**
1700  * synth_event_trace_start - Start piecewise synthetic event trace
1701  * @file: The trace_event_file representing the synthetic event
1702  * @trace_state: A pointer to object tracking the piecewise trace state
1703  *
1704  * Start the trace of a synthetic event field-by-field rather than all
1705  * at once.
1706  *
1707  * This function 'opens' an event trace, which means space is reserved
1708  * for the event in the trace buffer, after which the event's
1709  * individual field values can be set through either
1710  * synth_event_add_next_val() or synth_event_add_val().
1711  *
1712  * A pointer to a trace_state object is passed in, which will keep
1713  * track of the current event trace state until the event trace is
1714  * closed (and the event finally traced) using
1715  * synth_event_trace_end().
1716  *
1717  * Note that synth_event_trace_end() must be called after all values
1718  * have been added for each event trace, regardless of whether adding
1719  * all field values succeeded or not.
1720  *
1721  * Note also that for a given event trace, all fields must be added
1722  * using either synth_event_add_next_val() or synth_event_add_val()
1723  * but not both together or interleaved.
1724  *
1725  * Return: 0 on success, err otherwise.
1726  */
1727 int synth_event_trace_start(struct trace_event_file *file,
1728                             struct synth_event_trace_state *trace_state)
1729 {
1730         int ret;
1731
1732         if (!trace_state)
1733                 return -EINVAL;
1734
1735         ret = __synth_event_trace_init(file, trace_state);
1736         if (ret) {
1737                 if (ret == -ENOENT)
1738                         ret = 0; /* just disabled, not really an error */
1739                 return ret;
1740         }
1741
1742         if (trace_state->event->n_dynamic_fields)
1743                 return -ENOTSUPP;
1744
1745         ret = __synth_event_trace_start(file, trace_state, 0);
1746
1747         return ret;
1748 }
1749 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1750
1751 static int __synth_event_add_val(const char *field_name, u64 val,
1752                                  struct synth_event_trace_state *trace_state)
1753 {
1754         struct synth_field *field = NULL;
1755         struct synth_trace_event *entry;
1756         struct synth_event *event;
1757         int i, ret = 0;
1758
1759         if (!trace_state) {
1760                 ret = -EINVAL;
1761                 goto out;
1762         }
1763
1764         /* can't mix add_next_synth_val() with add_synth_val() */
1765         if (field_name) {
1766                 if (trace_state->add_next) {
1767                         ret = -EINVAL;
1768                         goto out;
1769                 }
1770                 trace_state->add_name = true;
1771         } else {
1772                 if (trace_state->add_name) {
1773                         ret = -EINVAL;
1774                         goto out;
1775                 }
1776                 trace_state->add_next = true;
1777         }
1778
1779         if (trace_state->disabled)
1780                 goto out;
1781
1782         event = trace_state->event;
1783         if (trace_state->add_name) {
1784                 for (i = 0; i < event->n_fields; i++) {
1785                         field = event->fields[i];
1786                         if (strcmp(field->name, field_name) == 0)
1787                                 break;
1788                 }
1789                 if (!field) {
1790                         ret = -EINVAL;
1791                         goto out;
1792                 }
1793         } else {
1794                 if (trace_state->cur_field >= event->n_fields) {
1795                         ret = -EINVAL;
1796                         goto out;
1797                 }
1798                 field = event->fields[trace_state->cur_field++];
1799         }
1800
1801         entry = trace_state->entry;
1802         if (field->is_string) {
1803                 char *str_val = (char *)(long)val;
1804                 char *str_field;
1805
1806                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
1807                         ret = -EINVAL;
1808                         goto out;
1809                 }
1810
1811                 if (!str_val) {
1812                         ret = -EINVAL;
1813                         goto out;
1814                 }
1815
1816                 str_field = (char *)&entry->fields[field->offset];
1817                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
1818         } else {
1819                 switch (field->size) {
1820                 case 1:
1821                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
1822                         break;
1823
1824                 case 2:
1825                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
1826                         break;
1827
1828                 case 4:
1829                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
1830                         break;
1831
1832                 default:
1833                         trace_state->entry->fields[field->offset] = val;
1834                         break;
1835                 }
1836         }
1837  out:
1838         return ret;
1839 }
1840
1841 /**
1842  * synth_event_add_next_val - Add the next field's value to an open synth trace
1843  * @val: The value to set the next field to
1844  * @trace_state: A pointer to object tracking the piecewise trace state
1845  *
1846  * Set the value of the next field in an event that's been opened by
1847  * synth_event_trace_start().
1848  *
1849  * The val param should be the value cast to u64.  If the value points
1850  * to a string, the val param should be a char * cast to u64.
1851  *
1852  * This function assumes all the fields in an event are to be set one
1853  * after another - successive calls to this function are made, one for
1854  * each field, in the order of the fields in the event, until all
1855  * fields have been set.  If you'd rather set each field individually
1856  * without regard to ordering, synth_event_add_val() can be used
1857  * instead.
1858  *
1859  * Note however that synth_event_add_next_val() and
1860  * synth_event_add_val() can't be intermixed for a given event trace -
1861  * one or the other but not both can be used at the same time.
1862  *
1863  * Note also that synth_event_trace_end() must be called after all
1864  * values have been added for each event trace, regardless of whether
1865  * adding all field values succeeded or not.
1866  *
1867  * Return: 0 on success, err otherwise.
1868  */
1869 int synth_event_add_next_val(u64 val,
1870                              struct synth_event_trace_state *trace_state)
1871 {
1872         return __synth_event_add_val(NULL, val, trace_state);
1873 }
1874 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
1875
1876 /**
1877  * synth_event_add_val - Add a named field's value to an open synth trace
1878  * @field_name: The name of the synthetic event field value to set
1879  * @val: The value to set the next field to
1880  * @trace_state: A pointer to object tracking the piecewise trace state
1881  *
1882  * Set the value of the named field in an event that's been opened by
1883  * synth_event_trace_start().
1884  *
1885  * The val param should be the value cast to u64.  If the value points
1886  * to a string, the val param should be a char * cast to u64.
1887  *
1888  * This function looks up the field name, and if found, sets the field
1889  * to the specified value.  This lookup makes this function more
1890  * expensive than synth_event_add_next_val(), so use that or the
1891  * none-piecewise synth_event_trace() instead if efficiency is more
1892  * important.
1893  *
1894  * Note however that synth_event_add_next_val() and
1895  * synth_event_add_val() can't be intermixed for a given event trace -
1896  * one or the other but not both can be used at the same time.
1897  *
1898  * Note also that synth_event_trace_end() must be called after all
1899  * values have been added for each event trace, regardless of whether
1900  * adding all field values succeeded or not.
1901  *
1902  * Return: 0 on success, err otherwise.
1903  */
1904 int synth_event_add_val(const char *field_name, u64 val,
1905                         struct synth_event_trace_state *trace_state)
1906 {
1907         return __synth_event_add_val(field_name, val, trace_state);
1908 }
1909 EXPORT_SYMBOL_GPL(synth_event_add_val);
1910
1911 /**
1912  * synth_event_trace_end - End piecewise synthetic event trace
1913  * @trace_state: A pointer to object tracking the piecewise trace state
1914  *
1915  * End the trace of a synthetic event opened by
1916  * synth_event_trace__start().
1917  *
1918  * This function 'closes' an event trace, which basically means that
1919  * it commits the reserved event and cleans up other loose ends.
1920  *
1921  * A pointer to a trace_state object is passed in, which will keep
1922  * track of the current event trace state opened with
1923  * synth_event_trace_start().
1924  *
1925  * Note that this function must be called after all values have been
1926  * added for each event trace, regardless of whether adding all field
1927  * values succeeded or not.
1928  *
1929  * Return: 0 on success, err otherwise.
1930  */
1931 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
1932 {
1933         if (!trace_state)
1934                 return -EINVAL;
1935
1936         __synth_event_trace_end(trace_state);
1937
1938         return 0;
1939 }
1940 EXPORT_SYMBOL_GPL(synth_event_trace_end);
1941
1942 static int create_synth_event(int argc, const char **argv)
1943 {
1944         const char *name = argv[0];
1945         int len;
1946
1947         if (name[0] != 's' || name[1] != ':')
1948                 return -ECANCELED;
1949         name += 2;
1950
1951         /* This interface accepts group name prefix */
1952         if (strchr(name, '/')) {
1953                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
1954                 if (len == 0)
1955                         return -EINVAL;
1956                 name += len;
1957         }
1958         return __create_synth_event(argc - 1, name, argv + 1);
1959 }
1960
1961 static int synth_event_release(struct dyn_event *ev)
1962 {
1963         struct synth_event *event = to_synth_event(ev);
1964         int ret;
1965
1966         if (event->ref)
1967                 return -EBUSY;
1968
1969         ret = unregister_synth_event(event);
1970         if (ret)
1971                 return ret;
1972
1973         dyn_event_remove(ev);
1974         free_synth_event(event);
1975         return 0;
1976 }
1977
1978 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
1979 {
1980         struct synth_field *field;
1981         unsigned int i;
1982         char *type, *t;
1983
1984         seq_printf(m, "%s\t", event->name);
1985
1986         for (i = 0; i < event->n_fields; i++) {
1987                 field = event->fields[i];
1988
1989                 type = field->type;
1990                 t = strstr(type, "__data_loc");
1991                 if (t) { /* __data_loc belongs in format but not event desc */
1992                         t += sizeof("__data_loc");
1993                         type = t;
1994                 }
1995
1996                 /* parameter values */
1997                 seq_printf(m, "%s %s%s", type, field->name,
1998                            i == event->n_fields - 1 ? "" : "; ");
1999         }
2000
2001         seq_putc(m, '\n');
2002
2003         return 0;
2004 }
2005
2006 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2007 {
2008         struct synth_event *event = to_synth_event(ev);
2009
2010         seq_printf(m, "s:%s/", event->class.system);
2011
2012         return __synth_event_show(m, event);
2013 }
2014
2015 static int synth_events_seq_show(struct seq_file *m, void *v)
2016 {
2017         struct dyn_event *ev = v;
2018
2019         if (!is_synth_event(ev))
2020                 return 0;
2021
2022         return __synth_event_show(m, to_synth_event(ev));
2023 }
2024
2025 static const struct seq_operations synth_events_seq_op = {
2026         .start  = dyn_event_seq_start,
2027         .next   = dyn_event_seq_next,
2028         .stop   = dyn_event_seq_stop,
2029         .show   = synth_events_seq_show,
2030 };
2031
2032 static int synth_events_open(struct inode *inode, struct file *file)
2033 {
2034         int ret;
2035
2036         ret = security_locked_down(LOCKDOWN_TRACEFS);
2037         if (ret)
2038                 return ret;
2039
2040         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2041                 ret = dyn_events_release_all(&synth_event_ops);
2042                 if (ret < 0)
2043                         return ret;
2044         }
2045
2046         return seq_open(file, &synth_events_seq_op);
2047 }
2048
2049 static ssize_t synth_events_write(struct file *file,
2050                                   const char __user *buffer,
2051                                   size_t count, loff_t *ppos)
2052 {
2053         return trace_parse_run_command(file, buffer, count, ppos,
2054                                        create_or_delete_synth_event);
2055 }
2056
2057 static const struct file_operations synth_events_fops = {
2058         .open           = synth_events_open,
2059         .write          = synth_events_write,
2060         .read           = seq_read,
2061         .llseek         = seq_lseek,
2062         .release        = seq_release,
2063 };
2064
2065 /*
2066  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2067  * events in postcore_initcall without tracefs.
2068  */
2069 static __init int trace_events_synth_init_early(void)
2070 {
2071         int err = 0;
2072
2073         err = dyn_event_register(&synth_event_ops);
2074         if (err)
2075                 pr_warn("Could not register synth_event_ops\n");
2076
2077         return err;
2078 }
2079 core_initcall(trace_events_synth_init_early);
2080
2081 static __init int trace_events_synth_init(void)
2082 {
2083         struct dentry *entry = NULL;
2084         int err = 0;
2085         err = tracing_init_dentry();
2086         if (err)
2087                 goto err;
2088
2089         entry = tracefs_create_file("synthetic_events", 0644, NULL,
2090                                     NULL, &synth_events_fops);
2091         if (!entry) {
2092                 err = -ENODEV;
2093                 goto err;
2094         }
2095
2096         return err;
2097  err:
2098         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2099
2100         return err;
2101 }
2102
2103 fs_initcall(trace_events_synth_init);