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 #include "trace_probe.h"
  21 #include "trace_probe_kernel.h"
  22
  23 #include "trace_synth.h"
  24
  25 #undef ERRORS
  26 #define ERRORS  \
  27         C(BAD_NAME,             "Illegal name"),                \
  28         C(INVALID_CMD,          "Command must be of the form: <name> field[;field] ..."),\
  29         C(INVALID_DYN_CMD,      "Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
  30         C(EVENT_EXISTS,         "Event already exists"),        \
  31         C(TOO_MANY_FIELDS,      "Too many fields"),             \
  32         C(INCOMPLETE_TYPE,      "Incomplete type"),             \
  33         C(INVALID_TYPE,         "Invalid type"),                \
  34         C(INVALID_FIELD,        "Invalid field"),               \
  35         C(INVALID_ARRAY_SPEC,   "Invalid array specification"),
  36
  37 #undef C
  38 #define C(a, b)         SYNTH_ERR_##a
  39
  40 enum { ERRORS };
  41
  42 #undef C
  43 #define C(a, b)         b
  44
  45 static const char *err_text[] = { ERRORS };
  46
  47 static DEFINE_MUTEX(lastcmd_mutex);
  48 static char *last_cmd;
  49
  50 static int errpos(const char *str)
  51 {
  52         int ret = 0;
  53
  54         mutex_lock(&lastcmd_mutex);
  55         if (!str || !last_cmd)
  56                 goto out;
  57
  58         ret = err_pos(last_cmd, str);
  59  out:
  60         mutex_unlock(&lastcmd_mutex);
  61         return ret;
  62 }
  63
  64 static void last_cmd_set(const char *str)
  65 {
  66         if (!str)
  67                 return;
  68
  69         mutex_lock(&lastcmd_mutex);
  70         kfree(last_cmd);
  71         last_cmd = kstrdup(str, GFP_KERNEL);
  72         mutex_unlock(&lastcmd_mutex);
  73 }
  74
  75 static void synth_err(u8 err_type, u16 err_pos)
  76 {
  77         mutex_lock(&lastcmd_mutex);
  78         if (!last_cmd)
  79                 goto out;
  80
  81         tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
  82                         err_type, err_pos);
  83  out:
  84         mutex_unlock(&lastcmd_mutex);
  85 }
  86
  87 static int create_synth_event(const char *raw_command);
  88 static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
  89 static int synth_event_release(struct dyn_event *ev);
  90 static bool synth_event_is_busy(struct dyn_event *ev);
  91 static bool synth_event_match(const char *system, const char *event,
  92                         int argc, const char **argv, struct dyn_event *ev);
  93
  94 static struct dyn_event_operations synth_event_ops = {
  95         .create = create_synth_event,
  96         .show = synth_event_show,
  97         .is_busy = synth_event_is_busy,
  98         .free = synth_event_release,
  99         .match = synth_event_match,
 100 };
 101
 102 static bool is_synth_event(struct dyn_event *ev)
 103 {
 104         return ev->ops == &synth_event_ops;
 105 }
 106
 107 static struct synth_event *to_synth_event(struct dyn_event *ev)
 108 {
 109         return container_of(ev, struct synth_event, devent);
 110 }
 111
 112 static bool synth_event_is_busy(struct dyn_event *ev)
 113 {
 114         struct synth_event *event = to_synth_event(ev);
 115
 116         return event->ref != 0;
 117 }
 118
 119 static bool synth_event_match(const char *system, const char *event,
 120                         int argc, const char **argv, struct dyn_event *ev)
 121 {
 122         struct synth_event *sev = to_synth_event(ev);
 123
 124         return strcmp(sev->name, event) == 0 &&
 125                 (!system || strcmp(system, SYNTH_SYSTEM) == 0);
 126 }
 127
 128 struct synth_trace_event {
 129         struct trace_entry      ent;
 130         u64                     fields[];
 131 };
 132
 133 static int synth_event_define_fields(struct trace_event_call *call)
 134 {
 135         struct synth_trace_event trace;
 136         int offset = offsetof(typeof(trace), fields);
 137         struct synth_event *event = call->data;
 138         unsigned int i, size, n_u64;
 139         char *name, *type;
 140         bool is_signed;
 141         int ret = 0;
 142
 143         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 144                 size = event->fields[i]->size;
 145                 is_signed = event->fields[i]->is_signed;
 146                 type = event->fields[i]->type;
 147                 name = event->fields[i]->name;
 148                 ret = trace_define_field(call, type, name, offset, size,
 149                                          is_signed, FILTER_OTHER);
 150                 if (ret)
 151                         break;
 152
 153                 event->fields[i]->offset = n_u64;
 154
 155                 if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
 156                         offset += STR_VAR_LEN_MAX;
 157                         n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 158                 } else {
 159                         offset += sizeof(u64);
 160                         n_u64++;
 161                 }
 162         }
 163
 164         event->n_u64 = n_u64;
 165
 166         return ret;
 167 }
 168
 169 static bool synth_field_signed(char *type)
 170 {
 171         if (str_has_prefix(type, "u"))
 172                 return false;
 173         if (strcmp(type, "gfp_t") == 0)
 174                 return false;
 175
 176         return true;
 177 }
 178
 179 static int synth_field_is_string(char *type)
 180 {
 181         if (strstr(type, "char[") != NULL)
 182                 return true;
 183
 184         return false;
 185 }
 186
 187 static int synth_field_is_stack(char *type)
 188 {
 189         if (strstr(type, "long[") != NULL)
 190                 return true;
 191
 192         return false;
 193 }
 194
 195 static int synth_field_string_size(char *type)
 196 {
 197         char buf[4], *end, *start;
 198         unsigned int len;
 199         int size, err;
 200
 201         start = strstr(type, "char[");
 202         if (start == NULL)
 203                 return -EINVAL;
 204         start += sizeof("char[") - 1;
 205
 206         end = strchr(type, ']');
 207         if (!end || end < start || type + strlen(type) > end + 1)
 208                 return -EINVAL;
 209
 210         len = end - start;
 211         if (len > 3)
 212                 return -EINVAL;
 213
 214         if (len == 0)
 215                 return 0; /* variable-length string */
 216
 217         strncpy(buf, start, len);
 218         buf[len] = '\0';
 219
 220         err = kstrtouint(buf, 0, &size);
 221         if (err)
 222                 return err;
 223
 224         if (size > STR_VAR_LEN_MAX)
 225                 return -EINVAL;
 226
 227         return size;
 228 }
 229
 230 static int synth_field_size(char *type)
 231 {
 232         int size = 0;
 233
 234         if (strcmp(type, "s64") == 0)
 235                 size = sizeof(s64);
 236         else if (strcmp(type, "u64") == 0)
 237                 size = sizeof(u64);
 238         else if (strcmp(type, "s32") == 0)
 239                 size = sizeof(s32);
 240         else if (strcmp(type, "u32") == 0)
 241                 size = sizeof(u32);
 242         else if (strcmp(type, "s16") == 0)
 243                 size = sizeof(s16);
 244         else if (strcmp(type, "u16") == 0)
 245                 size = sizeof(u16);
 246         else if (strcmp(type, "s8") == 0)
 247                 size = sizeof(s8);
 248         else if (strcmp(type, "u8") == 0)
 249                 size = sizeof(u8);
 250         else if (strcmp(type, "char") == 0)
 251                 size = sizeof(char);
 252         else if (strcmp(type, "unsigned char") == 0)
 253                 size = sizeof(unsigned char);
 254         else if (strcmp(type, "int") == 0)
 255                 size = sizeof(int);
 256         else if (strcmp(type, "unsigned int") == 0)
 257                 size = sizeof(unsigned int);
 258         else if (strcmp(type, "long") == 0)
 259                 size = sizeof(long);
 260         else if (strcmp(type, "unsigned long") == 0)
 261                 size = sizeof(unsigned long);
 262         else if (strcmp(type, "bool") == 0)
 263                 size = sizeof(bool);
 264         else if (strcmp(type, "pid_t") == 0)
 265                 size = sizeof(pid_t);
 266         else if (strcmp(type, "gfp_t") == 0)
 267                 size = sizeof(gfp_t);
 268         else if (synth_field_is_string(type))
 269                 size = synth_field_string_size(type);
 270         else if (synth_field_is_stack(type))
 271                 size = 0;
 272
 273         return size;
 274 }
 275
 276 static const char *synth_field_fmt(char *type)
 277 {
 278         const char *fmt = "%llu";
 279
 280         if (strcmp(type, "s64") == 0)
 281                 fmt = "%lld";
 282         else if (strcmp(type, "u64") == 0)
 283                 fmt = "%llu";
 284         else if (strcmp(type, "s32") == 0)
 285                 fmt = "%d";
 286         else if (strcmp(type, "u32") == 0)
 287                 fmt = "%u";
 288         else if (strcmp(type, "s16") == 0)
 289                 fmt = "%d";
 290         else if (strcmp(type, "u16") == 0)
 291                 fmt = "%u";
 292         else if (strcmp(type, "s8") == 0)
 293                 fmt = "%d";
 294         else if (strcmp(type, "u8") == 0)
 295                 fmt = "%u";
 296         else if (strcmp(type, "char") == 0)
 297                 fmt = "%d";
 298         else if (strcmp(type, "unsigned char") == 0)
 299                 fmt = "%u";
 300         else if (strcmp(type, "int") == 0)
 301                 fmt = "%d";
 302         else if (strcmp(type, "unsigned int") == 0)
 303                 fmt = "%u";
 304         else if (strcmp(type, "long") == 0)
 305                 fmt = "%ld";
 306         else if (strcmp(type, "unsigned long") == 0)
 307                 fmt = "%lu";
 308         else if (strcmp(type, "bool") == 0)
 309                 fmt = "%d";
 310         else if (strcmp(type, "pid_t") == 0)
 311                 fmt = "%d";
 312         else if (strcmp(type, "gfp_t") == 0)
 313                 fmt = "%x";
 314         else if (synth_field_is_string(type))
 315                 fmt = "%.*s";
 316         else if (synth_field_is_stack(type))
 317                 fmt = "%s";
 318
 319         return fmt;
 320 }
 321
 322 static void print_synth_event_num_val(struct trace_seq *s,
 323                                       char *print_fmt, char *name,
 324                                       int size, u64 val, char *space)
 325 {
 326         switch (size) {
 327         case 1:
 328                 trace_seq_printf(s, print_fmt, name, (u8)val, space);
 329                 break;
 330
 331         case 2:
 332                 trace_seq_printf(s, print_fmt, name, (u16)val, space);
 333                 break;
 334
 335         case 4:
 336                 trace_seq_printf(s, print_fmt, name, (u32)val, space);
 337                 break;
 338
 339         default:
 340                 trace_seq_printf(s, print_fmt, name, val, space);
 341                 break;
 342         }
 343 }
 344
 345 static enum print_line_t print_synth_event(struct trace_iterator *iter,
 346                                            int flags,
 347                                            struct trace_event *event)
 348 {
 349         struct trace_array *tr = iter->tr;
 350         struct trace_seq *s = &iter->seq;
 351         struct synth_trace_event *entry;
 352         struct synth_event *se;
 353         unsigned int i, n_u64;
 354         char print_fmt[32];
 355         const char *fmt;
 356
 357         entry = (struct synth_trace_event *)iter->ent;
 358         se = container_of(event, struct synth_event, call.event);
 359
 360         trace_seq_printf(s, "%s: ", se->name);
 361
 362         for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
 363                 if (trace_seq_has_overflowed(s))
 364                         goto end;
 365
 366                 fmt = synth_field_fmt(se->fields[i]->type);
 367
 368                 /* parameter types */
 369                 if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
 370                         trace_seq_printf(s, "%s ", fmt);
 371
 372                 snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
 373
 374                 /* parameter values */
 375                 if (se->fields[i]->is_string) {
 376                         if (se->fields[i]->is_dynamic) {
 377                                 u32 offset, data_offset;
 378                                 char *str_field;
 379
 380                                 offset = (u32)entry->fields[n_u64];
 381                                 data_offset = offset & 0xffff;
 382
 383                                 str_field = (char *)entry + data_offset;
 384
 385                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 386                                                  STR_VAR_LEN_MAX,
 387                                                  str_field,
 388                                                  i == se->n_fields - 1 ? "" : " ");
 389                                 n_u64++;
 390                         } else {
 391                                 trace_seq_printf(s, print_fmt, se->fields[i]->name,
 392                                                  STR_VAR_LEN_MAX,
 393                                                  (char *)&entry->fields[n_u64],
 394                                                  i == se->n_fields - 1 ? "" : " ");
 395                                 n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 396                         }
 397                 } else if (se->fields[i]->is_stack) {
 398                         u32 offset, data_offset, len;
 399                         unsigned long *p, *end;
 400
 401                         offset = (u32)entry->fields[n_u64];
 402                         data_offset = offset & 0xffff;
 403                         len = offset >> 16;
 404
 405                         p = (void *)entry + data_offset;
 406                         end = (void *)p + len - (sizeof(long) - 1);
 407
 408                         trace_seq_printf(s, "%s=STACK:\n", se->fields[i]->name);
 409
 410                         for (; *p && p < end; p++)
 411                                 trace_seq_printf(s, "=> %pS\n", (void *)*p);
 412                         n_u64++;
 413
 414                 } else {
 415                         struct trace_print_flags __flags[] = {
 416                             __def_gfpflag_names, {-1, NULL} };
 417                         char *space = (i == se->n_fields - 1 ? "" : " ");
 418
 419                         print_synth_event_num_val(s, print_fmt,
 420                                                   se->fields[i]->name,
 421                                                   se->fields[i]->size,
 422                                                   entry->fields[n_u64],
 423                                                   space);
 424
 425                         if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
 426                                 trace_seq_puts(s, " (");
 427                                 trace_print_flags_seq(s, "|",
 428                                                       entry->fields[n_u64],
 429                                                       __flags);
 430                                 trace_seq_putc(s, ')');
 431                         }
 432                         n_u64++;
 433                 }
 434         }
 435 end:
 436         trace_seq_putc(s, '\n');
 437
 438         return trace_handle_return(s);
 439 }
 440
 441 static struct trace_event_functions synth_event_funcs = {
 442         .trace          = print_synth_event
 443 };
 444
 445 static unsigned int trace_string(struct synth_trace_event *entry,
 446                                  struct synth_event *event,
 447                                  char *str_val,
 448                                  bool is_dynamic,
 449                                  unsigned int data_size,
 450                                  unsigned int *n_u64)
 451 {
 452         unsigned int len = 0;
 453         char *str_field;
 454         int ret;
 455
 456         if (is_dynamic) {
 457                 u32 data_offset;
 458
 459                 data_offset = struct_size(entry, fields, event->n_u64);
 460                 data_offset += data_size;
 461
 462                 len = fetch_store_strlen((unsigned long)str_val);
 463
 464                 data_offset |= len << 16;
 465                 *(u32 *)&entry->fields[*n_u64] = data_offset;
 466
 467                 ret = fetch_store_string((unsigned long)str_val, &entry->fields[*n_u64], entry);
 468
 469                 (*n_u64)++;
 470         } else {
 471                 str_field = (char *)&entry->fields[*n_u64];
 472
 473 #ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
 474                 if ((unsigned long)str_val < TASK_SIZE)
 475                         ret = strncpy_from_user_nofault(str_field, str_val, STR_VAR_LEN_MAX);
 476                 else
 477 #endif
 478                         ret = strncpy_from_kernel_nofault(str_field, str_val, STR_VAR_LEN_MAX);
 479
 480                 if (ret < 0)
 481                         strcpy(str_field, FAULT_STRING);
 482
 483                 (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
 484         }
 485
 486         return len;
 487 }
 488
 489 static unsigned int trace_stack(struct synth_trace_event *entry,
 490                                  struct synth_event *event,
 491                                  long *stack,
 492                                  unsigned int data_size,
 493                                  unsigned int *n_u64)
 494 {
 495         unsigned int len;
 496         u32 data_offset;
 497         void *data_loc;
 498
 499         data_offset = struct_size(entry, fields, event->n_u64);
 500         data_offset += data_size;
 501
 502         for (len = 0; len < HIST_STACKTRACE_DEPTH; len++) {
 503                 if (!stack[len])
 504                         break;
 505         }
 506
 507         /* Include the zero'd element if it fits */
 508         if (len < HIST_STACKTRACE_DEPTH)
 509                 len++;
 510
 511         len *= sizeof(long);
 512
 513         /* Find the dynamic section to copy the stack into. */
 514         data_loc = (void *)entry + data_offset;
 515         memcpy(data_loc, stack, len);
 516
 517         /* Fill in the field that holds the offset/len combo */
 518         data_offset |= len << 16;
 519         *(u32 *)&entry->fields[*n_u64] = data_offset;
 520
 521         (*n_u64)++;
 522
 523         return len;
 524 }
 525
 526 static notrace void trace_event_raw_event_synth(void *__data,
 527                                                 u64 *var_ref_vals,
 528                                                 unsigned int *var_ref_idx)
 529 {
 530         unsigned int i, n_u64, val_idx, len, data_size = 0;
 531         struct trace_event_file *trace_file = __data;
 532         struct synth_trace_event *entry;
 533         struct trace_event_buffer fbuffer;
 534         struct trace_buffer *buffer;
 535         struct synth_event *event;
 536         int fields_size = 0;
 537
 538         event = trace_file->event_call->data;
 539
 540         if (trace_trigger_soft_disabled(trace_file))
 541                 return;
 542
 543         fields_size = event->n_u64 * sizeof(u64);
 544
 545         for (i = 0; i < event->n_dynamic_fields; i++) {
 546                 unsigned int field_pos = event->dynamic_fields[i]->field_pos;
 547                 char *str_val;
 548
 549                 val_idx = var_ref_idx[field_pos];
 550                 str_val = (char *)(long)var_ref_vals[val_idx];
 551
 552                 if (event->dynamic_fields[i]->is_stack) {
 553                         len = *((unsigned long *)str_val);
 554                         len *= sizeof(unsigned long);
 555                 } else {
 556                         len = fetch_store_strlen((unsigned long)str_val);
 557                 }
 558
 559                 fields_size += len;
 560         }
 561
 562         /*
 563          * Avoid ring buffer recursion detection, as this event
 564          * is being performed within another event.
 565          */
 566         buffer = trace_file->tr->array_buffer.buffer;
 567         ring_buffer_nest_start(buffer);
 568
 569         entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 570                                            sizeof(*entry) + fields_size);
 571         if (!entry)
 572                 goto out;
 573
 574         for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 575                 val_idx = var_ref_idx[i];
 576                 if (event->fields[i]->is_string) {
 577                         char *str_val = (char *)(long)var_ref_vals[val_idx];
 578
 579                         len = trace_string(entry, event, str_val,
 580                                            event->fields[i]->is_dynamic,
 581                                            data_size, &n_u64);
 582                         data_size += len; /* only dynamic string increments */
 583                 } else if (event->fields[i]->is_stack) {
 584                         long *stack = (long *)(long)var_ref_vals[val_idx];
 585
 586                         len = trace_stack(entry, event, stack,
 587                                            data_size, &n_u64);
 588                         data_size += len;
 589                 } else {
 590                         struct synth_field *field = event->fields[i];
 591                         u64 val = var_ref_vals[val_idx];
 592
 593                         switch (field->size) {
 594                         case 1:
 595                                 *(u8 *)&entry->fields[n_u64] = (u8)val;
 596                                 break;
 597
 598                         case 2:
 599                                 *(u16 *)&entry->fields[n_u64] = (u16)val;
 600                                 break;
 601
 602                         case 4:
 603                                 *(u32 *)&entry->fields[n_u64] = (u32)val;
 604                                 break;
 605
 606                         default:
 607                                 entry->fields[n_u64] = val;
 608                                 break;
 609                         }
 610                         n_u64++;
 611                 }
 612         }
 613
 614         trace_event_buffer_commit(&fbuffer);
 615 out:
 616         ring_buffer_nest_end(buffer);
 617 }
 618
 619 static void free_synth_event_print_fmt(struct trace_event_call *call)
 620 {
 621         if (call) {
 622                 kfree(call->print_fmt);
 623                 call->print_fmt = NULL;
 624         }
 625 }
 626
 627 static int __set_synth_event_print_fmt(struct synth_event *event,
 628                                        char *buf, int len)
 629 {
 630         const char *fmt;
 631         int pos = 0;
 632         int i;
 633
 634         /* When len=0, we just calculate the needed length */
 635 #define LEN_OR_ZERO (len ? len - pos : 0)
 636
 637         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 638         for (i = 0; i < event->n_fields; i++) {
 639                 fmt = synth_field_fmt(event->fields[i]->type);
 640                 pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 641                                 event->fields[i]->name, fmt,
 642                                 i == event->n_fields - 1 ? "" : ", ");
 643         }
 644         pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 645
 646         for (i = 0; i < event->n_fields; i++) {
 647                 if (event->fields[i]->is_string &&
 648                     event->fields[i]->is_dynamic)
 649                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 650                                 ", __get_str(%s)", event->fields[i]->name);
 651                 else if (event->fields[i]->is_stack)
 652                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 653                                 ", __get_stacktrace(%s)", event->fields[i]->name);
 654                 else
 655                         pos += snprintf(buf + pos, LEN_OR_ZERO,
 656                                         ", REC->%s", event->fields[i]->name);
 657         }
 658
 659 #undef LEN_OR_ZERO
 660
 661         /* return the length of print_fmt */
 662         return pos;
 663 }
 664
 665 static int set_synth_event_print_fmt(struct trace_event_call *call)
 666 {
 667         struct synth_event *event = call->data;
 668         char *print_fmt;
 669         int len;
 670
 671         /* First: called with 0 length to calculate the needed length */
 672         len = __set_synth_event_print_fmt(event, NULL, 0);
 673
 674         print_fmt = kmalloc(len + 1, GFP_KERNEL);
 675         if (!print_fmt)
 676                 return -ENOMEM;
 677
 678         /* Second: actually write the @print_fmt */
 679         __set_synth_event_print_fmt(event, print_fmt, len + 1);
 680         call->print_fmt = print_fmt;
 681
 682         return 0;
 683 }
 684
 685 static void free_synth_field(struct synth_field *field)
 686 {
 687         kfree(field->type);
 688         kfree(field->name);
 689         kfree(field);
 690 }
 691
 692 static int check_field_version(const char *prefix, const char *field_type,
 693                                const char *field_name)
 694 {
 695         /*
 696          * For backward compatibility, the old synthetic event command
 697          * format did not require semicolons, and in order to not
 698          * break user space, that old format must still work. If a new
 699          * feature is added, then the format that uses the new feature
 700          * will be required to have semicolons, as nothing that uses
 701          * the old format would be using the new, yet to be created,
 702          * feature. When a new feature is added, this will detect it,
 703          * and return a number greater than 1, and require the format
 704          * to use semicolons.
 705          */
 706         return 1;
 707 }
 708
 709 static struct synth_field *parse_synth_field(int argc, char **argv,
 710                                              int *consumed, int *field_version)
 711 {
 712         const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 713         struct synth_field *field;
 714         int len, ret = -ENOMEM;
 715         struct seq_buf s;
 716         ssize_t size;
 717
 718         if (!strcmp(field_type, "unsigned")) {
 719                 if (argc < 3) {
 720                         synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 721                         return ERR_PTR(-EINVAL);
 722                 }
 723                 prefix = "unsigned ";
 724                 field_type = argv[1];
 725                 field_name = argv[2];
 726                 *consumed += 3;
 727         } else {
 728                 field_name = argv[1];
 729                 *consumed += 2;
 730         }
 731
 732         if (!field_name) {
 733                 synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
 734                 return ERR_PTR(-EINVAL);
 735         }
 736
 737         *field_version = check_field_version(prefix, field_type, field_name);
 738
 739         field = kzalloc(sizeof(*field), GFP_KERNEL);
 740         if (!field)
 741                 return ERR_PTR(-ENOMEM);
 742
 743         len = strlen(field_name);
 744         array = strchr(field_name, '[');
 745         if (array)
 746                 len -= strlen(array);
 747
 748         field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 749         if (!field->name)
 750                 goto free;
 751
 752         if (!is_good_name(field->name)) {
 753                 synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 754                 ret = -EINVAL;
 755                 goto free;
 756         }
 757
 758         len = strlen(field_type) + 1;
 759
 760         if (array)
 761                 len += strlen(array);
 762
 763         if (prefix)
 764                 len += strlen(prefix);
 765
 766         field->type = kzalloc(len, GFP_KERNEL);
 767         if (!field->type)
 768                 goto free;
 769
 770         seq_buf_init(&s, field->type, len);
 771         if (prefix)
 772                 seq_buf_puts(&s, prefix);
 773         seq_buf_puts(&s, field_type);
 774         if (array)
 775                 seq_buf_puts(&s, array);
 776         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 777                 goto free;
 778
 779         s.buffer[s.len] = '\0';
 780
 781         size = synth_field_size(field->type);
 782         if (size < 0) {
 783                 if (array)
 784                         synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
 785                 else
 786                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 787                 ret = -EINVAL;
 788                 goto free;
 789         } else if (size == 0) {
 790                 if (synth_field_is_string(field->type) ||
 791                     synth_field_is_stack(field->type)) {
 792                         char *type;
 793
 794                         len = sizeof("__data_loc ") + strlen(field->type) + 1;
 795                         type = kzalloc(len, GFP_KERNEL);
 796                         if (!type)
 797                                 goto free;
 798
 799                         seq_buf_init(&s, type, len);
 800                         seq_buf_puts(&s, "__data_loc ");
 801                         seq_buf_puts(&s, field->type);
 802
 803                         if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 804                                 goto free;
 805                         s.buffer[s.len] = '\0';
 806
 807                         kfree(field->type);
 808                         field->type = type;
 809
 810                         field->is_dynamic = true;
 811                         size = sizeof(u64);
 812                 } else {
 813                         synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 814                         ret = -EINVAL;
 815                         goto free;
 816                 }
 817         }
 818         field->size = size;
 819
 820         if (synth_field_is_string(field->type))
 821                 field->is_string = true;
 822         else if (synth_field_is_stack(field->type))
 823                 field->is_stack = true;
 824
 825         field->is_signed = synth_field_signed(field->type);
 826  out:
 827         return field;
 828  free:
 829         free_synth_field(field);
 830         field = ERR_PTR(ret);
 831         goto out;
 832 }
 833
 834 static void free_synth_tracepoint(struct tracepoint *tp)
 835 {
 836         if (!tp)
 837                 return;
 838
 839         kfree(tp->name);
 840         kfree(tp);
 841 }
 842
 843 static struct tracepoint *alloc_synth_tracepoint(char *name)
 844 {
 845         struct tracepoint *tp;
 846
 847         tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 848         if (!tp)
 849                 return ERR_PTR(-ENOMEM);
 850
 851         tp->name = kstrdup(name, GFP_KERNEL);
 852         if (!tp->name) {
 853                 kfree(tp);
 854                 return ERR_PTR(-ENOMEM);
 855         }
 856
 857         return tp;
 858 }
 859
 860 struct synth_event *find_synth_event(const char *name)
 861 {
 862         struct dyn_event *pos;
 863         struct synth_event *event;
 864
 865         for_each_dyn_event(pos) {
 866                 if (!is_synth_event(pos))
 867                         continue;
 868                 event = to_synth_event(pos);
 869                 if (strcmp(event->name, name) == 0)
 870                         return event;
 871         }
 872
 873         return NULL;
 874 }
 875
 876 static struct trace_event_fields synth_event_fields_array[] = {
 877         { .type = TRACE_FUNCTION_TYPE,
 878           .define_fields = synth_event_define_fields },
 879         {}
 880 };
 881
 882 static int register_synth_event(struct synth_event *event)
 883 {
 884         struct trace_event_call *call = &event->call;
 885         int ret = 0;
 886
 887         event->call.class = &event->class;
 888         event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 889         if (!event->class.system) {
 890                 ret = -ENOMEM;
 891                 goto out;
 892         }
 893
 894         event->tp = alloc_synth_tracepoint(event->name);
 895         if (IS_ERR(event->tp)) {
 896                 ret = PTR_ERR(event->tp);
 897                 event->tp = NULL;
 898                 goto out;
 899         }
 900
 901         INIT_LIST_HEAD(&call->class->fields);
 902         call->event.funcs = &synth_event_funcs;
 903         call->class->fields_array = synth_event_fields_array;
 904
 905         ret = register_trace_event(&call->event);
 906         if (!ret) {
 907                 ret = -ENODEV;
 908                 goto out;
 909         }
 910         call->flags = TRACE_EVENT_FL_TRACEPOINT;
 911         call->class->reg = trace_event_reg;
 912         call->class->probe = trace_event_raw_event_synth;
 913         call->data = event;
 914         call->tp = event->tp;
 915
 916         ret = trace_add_event_call(call);
 917         if (ret) {
 918                 pr_warn("Failed to register synthetic event: %s\n",
 919                         trace_event_name(call));
 920                 goto err;
 921         }
 922
 923         ret = set_synth_event_print_fmt(call);
 924         /* unregister_trace_event() will be called inside */
 925         if (ret < 0)
 926                 trace_remove_event_call(call);
 927  out:
 928         return ret;
 929  err:
 930         unregister_trace_event(&call->event);
 931         goto out;
 932 }
 933
 934 static int unregister_synth_event(struct synth_event *event)
 935 {
 936         struct trace_event_call *call = &event->call;
 937         int ret;
 938
 939         ret = trace_remove_event_call(call);
 940
 941         return ret;
 942 }
 943
 944 static void free_synth_event(struct synth_event *event)
 945 {
 946         unsigned int i;
 947
 948         if (!event)
 949                 return;
 950
 951         for (i = 0; i < event->n_fields; i++)
 952                 free_synth_field(event->fields[i]);
 953
 954         kfree(event->fields);
 955         kfree(event->dynamic_fields);
 956         kfree(event->name);
 957         kfree(event->class.system);
 958         free_synth_tracepoint(event->tp);
 959         free_synth_event_print_fmt(&event->call);
 960         kfree(event);
 961 }
 962
 963 static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 964                                              struct synth_field **fields)
 965 {
 966         unsigned int i, j, n_dynamic_fields = 0;
 967         struct synth_event *event;
 968
 969         event = kzalloc(sizeof(*event), GFP_KERNEL);
 970         if (!event) {
 971                 event = ERR_PTR(-ENOMEM);
 972                 goto out;
 973         }
 974
 975         event->name = kstrdup(name, GFP_KERNEL);
 976         if (!event->name) {
 977                 kfree(event);
 978                 event = ERR_PTR(-ENOMEM);
 979                 goto out;
 980         }
 981
 982         event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 983         if (!event->fields) {
 984                 free_synth_event(event);
 985                 event = ERR_PTR(-ENOMEM);
 986                 goto out;
 987         }
 988
 989         for (i = 0; i < n_fields; i++)
 990                 if (fields[i]->is_dynamic)
 991                         n_dynamic_fields++;
 992
 993         if (n_dynamic_fields) {
 994                 event->dynamic_fields = kcalloc(n_dynamic_fields,
 995                                                 sizeof(*event->dynamic_fields),
 996                                                 GFP_KERNEL);
 997                 if (!event->dynamic_fields) {
 998                         free_synth_event(event);
 999                         event = ERR_PTR(-ENOMEM);
1000                         goto out;
1001                 }
1002         }
1003
1004         dyn_event_init(&event->devent, &synth_event_ops);
1005
1006         for (i = 0, j = 0; i < n_fields; i++) {
1007                 fields[i]->field_pos = i;
1008                 event->fields[i] = fields[i];
1009
1010                 if (fields[i]->is_dynamic)
1011                         event->dynamic_fields[j++] = fields[i];
1012         }
1013         event->n_dynamic_fields = j;
1014         event->n_fields = n_fields;
1015  out:
1016         return event;
1017 }
1018
1019 static int synth_event_check_arg_fn(void *data)
1020 {
1021         struct dynevent_arg_pair *arg_pair = data;
1022         int size;
1023
1024         size = synth_field_size((char *)arg_pair->lhs);
1025         if (size == 0) {
1026                 if (strstr((char *)arg_pair->lhs, "["))
1027                         return 0;
1028         }
1029
1030         return size ? 0 : -EINVAL;
1031 }
1032
1033 /**
1034  * synth_event_add_field - Add a new field to a synthetic event cmd
1035  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1036  * @type: The type of the new field to add
1037  * @name: The name of the new field to add
1038  *
1039  * Add a new field to a synthetic event cmd object.  Field ordering is in
1040  * the same order the fields are added.
1041  *
1042  * See synth_field_size() for available types. If field_name contains
1043  * [n] the field is considered to be an array.
1044  *
1045  * Return: 0 if successful, error otherwise.
1046  */
1047 int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
1048                           const char *name)
1049 {
1050         struct dynevent_arg_pair arg_pair;
1051         int ret;
1052
1053         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1054                 return -EINVAL;
1055
1056         if (!type || !name)
1057                 return -EINVAL;
1058
1059         dynevent_arg_pair_init(&arg_pair, 0, ';');
1060
1061         arg_pair.lhs = type;
1062         arg_pair.rhs = name;
1063
1064         ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
1065         if (ret)
1066                 return ret;
1067
1068         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1069                 ret = -EINVAL;
1070
1071         return ret;
1072 }
1073 EXPORT_SYMBOL_GPL(synth_event_add_field);
1074
1075 /**
1076  * synth_event_add_field_str - Add a new field to a synthetic event cmd
1077  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1078  * @type_name: The type and name of the new field to add, as a single string
1079  *
1080  * Add a new field to a synthetic event cmd object, as a single
1081  * string.  The @type_name string is expected to be of the form 'type
1082  * name', which will be appended by ';'.  No sanity checking is done -
1083  * what's passed in is assumed to already be well-formed.  Field
1084  * ordering is in the same order the fields are added.
1085  *
1086  * See synth_field_size() for available types. If field_name contains
1087  * [n] the field is considered to be an array.
1088  *
1089  * Return: 0 if successful, error otherwise.
1090  */
1091 int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
1092 {
1093         struct dynevent_arg arg;
1094         int ret;
1095
1096         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1097                 return -EINVAL;
1098
1099         if (!type_name)
1100                 return -EINVAL;
1101
1102         dynevent_arg_init(&arg, ';');
1103
1104         arg.str = type_name;
1105
1106         ret = dynevent_arg_add(cmd, &arg, NULL);
1107         if (ret)
1108                 return ret;
1109
1110         if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1111                 ret = -EINVAL;
1112
1113         return ret;
1114 }
1115 EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1116
1117 /**
1118  * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1119  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1120  * @fields: An array of type/name field descriptions
1121  * @n_fields: The number of field descriptions contained in the fields array
1122  *
1123  * Add a new set of fields to a synthetic event cmd object.  The event
1124  * fields that will be defined for the event should be passed in as an
1125  * array of struct synth_field_desc, and the number of elements in the
1126  * array passed in as n_fields.  Field ordering will retain the
1127  * ordering given in the fields array.
1128  *
1129  * See synth_field_size() for available types. If field_name contains
1130  * [n] the field is considered to be an array.
1131  *
1132  * Return: 0 if successful, error otherwise.
1133  */
1134 int synth_event_add_fields(struct dynevent_cmd *cmd,
1135                            struct synth_field_desc *fields,
1136                            unsigned int n_fields)
1137 {
1138         unsigned int i;
1139         int ret = 0;
1140
1141         for (i = 0; i < n_fields; i++) {
1142                 if (fields[i].type == NULL || fields[i].name == NULL) {
1143                         ret = -EINVAL;
1144                         break;
1145                 }
1146
1147                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1148                 if (ret)
1149                         break;
1150         }
1151
1152         return ret;
1153 }
1154 EXPORT_SYMBOL_GPL(synth_event_add_fields);
1155
1156 /**
1157  * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1158  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1159  * @name: The name of the synthetic event
1160  * @mod: The module creating the event, NULL if not created from a module
1161  * @args: Variable number of arg (pairs), one pair for each field
1162  *
1163  * NOTE: Users normally won't want to call this function directly, but
1164  * rather use the synth_event_gen_cmd_start() wrapper, which
1165  * automatically adds a NULL to the end of the arg list.  If this
1166  * function is used directly, make sure the last arg in the variable
1167  * arg list is NULL.
1168  *
1169  * Generate a synthetic event command to be executed by
1170  * synth_event_gen_cmd_end().  This function can be used to generate
1171  * the complete command or only the first part of it; in the latter
1172  * case, synth_event_add_field(), synth_event_add_field_str(), or
1173  * synth_event_add_fields() can be used to add more fields following
1174  * this.
1175  *
1176  * There should be an even number variable args, each pair consisting
1177  * of a type followed by a field name.
1178  *
1179  * See synth_field_size() for available types. If field_name contains
1180  * [n] the field is considered to be an array.
1181  *
1182  * Return: 0 if successful, error otherwise.
1183  */
1184 int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1185                                 struct module *mod, ...)
1186 {
1187         struct dynevent_arg arg;
1188         va_list args;
1189         int ret;
1190
1191         cmd->event_name = name;
1192         cmd->private_data = mod;
1193
1194         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1195                 return -EINVAL;
1196
1197         dynevent_arg_init(&arg, 0);
1198         arg.str = name;
1199         ret = dynevent_arg_add(cmd, &arg, NULL);
1200         if (ret)
1201                 return ret;
1202
1203         va_start(args, mod);
1204         for (;;) {
1205                 const char *type, *name;
1206
1207                 type = va_arg(args, const char *);
1208                 if (!type)
1209                         break;
1210                 name = va_arg(args, const char *);
1211                 if (!name)
1212                         break;
1213
1214                 if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1215                         ret = -EINVAL;
1216                         break;
1217                 }
1218
1219                 ret = synth_event_add_field(cmd, type, name);
1220                 if (ret)
1221                         break;
1222         }
1223         va_end(args);
1224
1225         return ret;
1226 }
1227 EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1228
1229 /**
1230  * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1231  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1232  * @name: The name of the synthetic event
1233  * @fields: An array of type/name field descriptions
1234  * @n_fields: The number of field descriptions contained in the fields array
1235  *
1236  * Generate a synthetic event command to be executed by
1237  * synth_event_gen_cmd_end().  This function can be used to generate
1238  * the complete command or only the first part of it; in the latter
1239  * case, synth_event_add_field(), synth_event_add_field_str(), or
1240  * synth_event_add_fields() can be used to add more fields following
1241  * this.
1242  *
1243  * The event fields that will be defined for the event should be
1244  * passed in as an array of struct synth_field_desc, and the number of
1245  * elements in the array passed in as n_fields.  Field ordering will
1246  * retain the ordering given in the fields array.
1247  *
1248  * See synth_field_size() for available types. If field_name contains
1249  * [n] the field is considered to be an array.
1250  *
1251  * Return: 0 if successful, error otherwise.
1252  */
1253 int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1254                                     struct module *mod,
1255                                     struct synth_field_desc *fields,
1256                                     unsigned int n_fields)
1257 {
1258         struct dynevent_arg arg;
1259         unsigned int i;
1260         int ret = 0;
1261
1262         cmd->event_name = name;
1263         cmd->private_data = mod;
1264
1265         if (cmd->type != DYNEVENT_TYPE_SYNTH)
1266                 return -EINVAL;
1267
1268         if (n_fields > SYNTH_FIELDS_MAX)
1269                 return -EINVAL;
1270
1271         dynevent_arg_init(&arg, 0);
1272         arg.str = name;
1273         ret = dynevent_arg_add(cmd, &arg, NULL);
1274         if (ret)
1275                 return ret;
1276
1277         for (i = 0; i < n_fields; i++) {
1278                 if (fields[i].type == NULL || fields[i].name == NULL)
1279                         return -EINVAL;
1280
1281                 ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1282                 if (ret)
1283                         break;
1284         }
1285
1286         return ret;
1287 }
1288 EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1289
1290 static int __create_synth_event(const char *name, const char *raw_fields)
1291 {
1292         char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1293         struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1294         int consumed, cmd_version = 1, n_fields_this_loop;
1295         int i, argc, n_fields = 0, ret = 0;
1296         struct synth_event *event = NULL;
1297
1298         /*
1299          * Argument syntax:
1300          *  - Add synthetic event: <event_name> field[;field] ...
1301          *  - Remove synthetic event: !<event_name> field[;field] ...
1302          *      where 'field' = type field_name
1303          */
1304
1305         if (name[0] == '\0') {
1306                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1307                 return -EINVAL;
1308         }
1309
1310         if (!is_good_name(name)) {
1311                 synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1312                 return -EINVAL;
1313         }
1314
1315         mutex_lock(&event_mutex);
1316
1317         event = find_synth_event(name);
1318         if (event) {
1319                 synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1320                 ret = -EEXIST;
1321                 goto err;
1322         }
1323
1324         tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1325         if (!tmp_fields) {
1326                 ret = -ENOMEM;
1327                 goto err;
1328         }
1329
1330         while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1331                 argv = argv_split(GFP_KERNEL, field_str, &argc);
1332                 if (!argv) {
1333                         ret = -ENOMEM;
1334                         goto err;
1335                 }
1336
1337                 if (!argc) {
1338                         argv_free(argv);
1339                         continue;
1340                 }
1341
1342                 n_fields_this_loop = 0;
1343                 consumed = 0;
1344                 while (argc > consumed) {
1345                         int field_version;
1346
1347                         field = parse_synth_field(argc - consumed,
1348                                                   argv + consumed, &consumed,
1349                                                   &field_version);
1350                         if (IS_ERR(field)) {
1351                                 ret = PTR_ERR(field);
1352                                 goto err_free_arg;
1353                         }
1354
1355                         /*
1356                          * Track the highest version of any field we
1357                          * found in the command.
1358                          */
1359                         if (field_version > cmd_version)
1360                                 cmd_version = field_version;
1361
1362                         /*
1363                          * Now sort out what is and isn't valid for
1364                          * each supported version.
1365                          *
1366                          * If we see more than 1 field per loop, it
1367                          * means we have multiple fields between
1368                          * semicolons, and that's something we no
1369                          * longer support in a version 2 or greater
1370                          * command.
1371                          */
1372                         if (cmd_version > 1 && n_fields_this_loop >= 1) {
1373                                 synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1374                                 ret = -EINVAL;
1375                                 goto err_free_arg;
1376                         }
1377
1378                         if (n_fields == SYNTH_FIELDS_MAX) {
1379                                 synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1380                                 ret = -EINVAL;
1381                                 goto err_free_arg;
1382                         }
1383                         fields[n_fields++] = field;
1384
1385                         n_fields_this_loop++;
1386                 }
1387                 argv_free(argv);
1388
1389                 if (consumed < argc) {
1390                         synth_err(SYNTH_ERR_INVALID_CMD, 0);
1391                         ret = -EINVAL;
1392                         goto err;
1393                 }
1394
1395         }
1396
1397         if (n_fields == 0) {
1398                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1399                 ret = -EINVAL;
1400                 goto err;
1401         }
1402
1403         event = alloc_synth_event(name, n_fields, fields);
1404         if (IS_ERR(event)) {
1405                 ret = PTR_ERR(event);
1406                 event = NULL;
1407                 goto err;
1408         }
1409         ret = register_synth_event(event);
1410         if (!ret)
1411                 dyn_event_add(&event->devent, &event->call);
1412         else
1413                 free_synth_event(event);
1414  out:
1415         mutex_unlock(&event_mutex);
1416
1417         kfree(saved_fields);
1418
1419         return ret;
1420  err_free_arg:
1421         argv_free(argv);
1422  err:
1423         for (i = 0; i < n_fields; i++)
1424                 free_synth_field(fields[i]);
1425
1426         goto out;
1427 }
1428
1429 /**
1430  * synth_event_create - Create a new synthetic event
1431  * @name: The name of the new synthetic event
1432  * @fields: An array of type/name field descriptions
1433  * @n_fields: The number of field descriptions contained in the fields array
1434  * @mod: The module creating the event, NULL if not created from a module
1435  *
1436  * Create a new synthetic event with the given name under the
1437  * trace/events/synthetic/ directory.  The event fields that will be
1438  * defined for the event should be passed in as an array of struct
1439  * synth_field_desc, and the number elements in the array passed in as
1440  * n_fields. Field ordering will retain the ordering given in the
1441  * fields array.
1442  *
1443  * If the new synthetic event is being created from a module, the mod
1444  * param must be non-NULL.  This will ensure that the trace buffer
1445  * won't contain unreadable events.
1446  *
1447  * The new synth event should be deleted using synth_event_delete()
1448  * function.  The new synthetic event can be generated from modules or
1449  * other kernel code using trace_synth_event() and related functions.
1450  *
1451  * Return: 0 if successful, error otherwise.
1452  */
1453 int synth_event_create(const char *name, struct synth_field_desc *fields,
1454                        unsigned int n_fields, struct module *mod)
1455 {
1456         struct dynevent_cmd cmd;
1457         char *buf;
1458         int ret;
1459
1460         buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1461         if (!buf)
1462                 return -ENOMEM;
1463
1464         synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1465
1466         ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1467                                               fields, n_fields);
1468         if (ret)
1469                 goto out;
1470
1471         ret = synth_event_gen_cmd_end(&cmd);
1472  out:
1473         kfree(buf);
1474
1475         return ret;
1476 }
1477 EXPORT_SYMBOL_GPL(synth_event_create);
1478
1479 static int destroy_synth_event(struct synth_event *se)
1480 {
1481         int ret;
1482
1483         if (se->ref)
1484                 return -EBUSY;
1485
1486         if (trace_event_dyn_busy(&se->call))
1487                 return -EBUSY;
1488
1489         ret = unregister_synth_event(se);
1490         if (!ret) {
1491                 dyn_event_remove(&se->devent);
1492                 free_synth_event(se);
1493         }
1494
1495         return ret;
1496 }
1497
1498 /**
1499  * synth_event_delete - Delete a synthetic event
1500  * @event_name: The name of the new synthetic event
1501  *
1502  * Delete a synthetic event that was created with synth_event_create().
1503  *
1504  * Return: 0 if successful, error otherwise.
1505  */
1506 int synth_event_delete(const char *event_name)
1507 {
1508         struct synth_event *se = NULL;
1509         struct module *mod = NULL;
1510         int ret = -ENOENT;
1511
1512         mutex_lock(&event_mutex);
1513         se = find_synth_event(event_name);
1514         if (se) {
1515                 mod = se->mod;
1516                 ret = destroy_synth_event(se);
1517         }
1518         mutex_unlock(&event_mutex);
1519
1520         if (mod) {
1521                 /*
1522                  * It is safest to reset the ring buffer if the module
1523                  * being unloaded registered any events that were
1524                  * used. The only worry is if a new module gets
1525                  * loaded, and takes on the same id as the events of
1526                  * this module. When printing out the buffer, traced
1527                  * events left over from this module may be passed to
1528                  * the new module events and unexpected results may
1529                  * occur.
1530                  */
1531                 tracing_reset_all_online_cpus();
1532         }
1533
1534         return ret;
1535 }
1536 EXPORT_SYMBOL_GPL(synth_event_delete);
1537
1538 static int check_command(const char *raw_command)
1539 {
1540         char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1541         int argc, ret = 0;
1542
1543         cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1544         if (!cmd)
1545                 return -ENOMEM;
1546
1547         name_and_field = strsep(&cmd, ";");
1548         if (!name_and_field) {
1549                 ret = -EINVAL;
1550                 goto free;
1551         }
1552
1553         if (name_and_field[0] == '!')
1554                 goto free;
1555
1556         argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1557         if (!argv) {
1558                 ret = -ENOMEM;
1559                 goto free;
1560         }
1561         argv_free(argv);
1562
1563         if (argc < 3)
1564                 ret = -EINVAL;
1565 free:
1566         kfree(saved_cmd);
1567
1568         return ret;
1569 }
1570
1571 static int create_or_delete_synth_event(const char *raw_command)
1572 {
1573         char *name = NULL, *fields, *p;
1574         int ret = 0;
1575
1576         raw_command = skip_spaces(raw_command);
1577         if (raw_command[0] == '\0')
1578                 return ret;
1579
1580         last_cmd_set(raw_command);
1581
1582         ret = check_command(raw_command);
1583         if (ret) {
1584                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1585                 return ret;
1586         }
1587
1588         p = strpbrk(raw_command, " \t");
1589         if (!p && raw_command[0] != '!') {
1590                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
1591                 ret = -EINVAL;
1592                 goto free;
1593         }
1594
1595         name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1596         if (!name)
1597                 return -ENOMEM;
1598
1599         if (name[0] == '!') {
1600                 ret = synth_event_delete(name + 1);
1601                 goto free;
1602         }
1603
1604         fields = skip_spaces(p);
1605
1606         ret = __create_synth_event(name, fields);
1607 free:
1608         kfree(name);
1609
1610         return ret;
1611 }
1612
1613 static int synth_event_run_command(struct dynevent_cmd *cmd)
1614 {
1615         struct synth_event *se;
1616         int ret;
1617
1618         ret = create_or_delete_synth_event(cmd->seq.buffer);
1619         if (ret)
1620                 return ret;
1621
1622         se = find_synth_event(cmd->event_name);
1623         if (WARN_ON(!se))
1624                 return -ENOENT;
1625
1626         se->mod = cmd->private_data;
1627
1628         return ret;
1629 }
1630
1631 /**
1632  * synth_event_cmd_init - Initialize a synthetic event command object
1633  * @cmd: A pointer to the dynevent_cmd struct representing the new event
1634  * @buf: A pointer to the buffer used to build the command
1635  * @maxlen: The length of the buffer passed in @buf
1636  *
1637  * Initialize a synthetic event command object.  Use this before
1638  * calling any of the other dyenvent_cmd functions.
1639  */
1640 void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1641 {
1642         dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1643                           synth_event_run_command);
1644 }
1645 EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1646
1647 static inline int
1648 __synth_event_trace_init(struct trace_event_file *file,
1649                          struct synth_event_trace_state *trace_state)
1650 {
1651         int ret = 0;
1652
1653         memset(trace_state, '\0', sizeof(*trace_state));
1654
1655         /*
1656          * Normal event tracing doesn't get called at all unless the
1657          * ENABLED bit is set (which attaches the probe thus allowing
1658          * this code to be called, etc).  Because this is called
1659          * directly by the user, we don't have that but we still need
1660          * to honor not logging when disabled.  For the iterated
1661          * trace case, we save the enabled state upon start and just
1662          * ignore the following data calls.
1663          */
1664         if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1665             trace_trigger_soft_disabled(file)) {
1666                 trace_state->disabled = true;
1667                 ret = -ENOENT;
1668                 goto out;
1669         }
1670
1671         trace_state->event = file->event_call->data;
1672 out:
1673         return ret;
1674 }
1675
1676 static inline int
1677 __synth_event_trace_start(struct trace_event_file *file,
1678                           struct synth_event_trace_state *trace_state,
1679                           int dynamic_fields_size)
1680 {
1681         int entry_size, fields_size = 0;
1682         int ret = 0;
1683
1684         fields_size = trace_state->event->n_u64 * sizeof(u64);
1685         fields_size += dynamic_fields_size;
1686
1687         /*
1688          * Avoid ring buffer recursion detection, as this event
1689          * is being performed within another event.
1690          */
1691         trace_state->buffer = file->tr->array_buffer.buffer;
1692         ring_buffer_nest_start(trace_state->buffer);
1693
1694         entry_size = sizeof(*trace_state->entry) + fields_size;
1695         trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1696                                                         file,
1697                                                         entry_size);
1698         if (!trace_state->entry) {
1699                 ring_buffer_nest_end(trace_state->buffer);
1700                 ret = -EINVAL;
1701         }
1702
1703         return ret;
1704 }
1705
1706 static inline void
1707 __synth_event_trace_end(struct synth_event_trace_state *trace_state)
1708 {
1709         trace_event_buffer_commit(&trace_state->fbuffer);
1710
1711         ring_buffer_nest_end(trace_state->buffer);
1712 }
1713
1714 /**
1715  * synth_event_trace - Trace a synthetic event
1716  * @file: The trace_event_file representing the synthetic event
1717  * @n_vals: The number of values in vals
1718  * @args: Variable number of args containing the event values
1719  *
1720  * Trace a synthetic event using the values passed in the variable
1721  * argument list.
1722  *
1723  * The argument list should be a list 'n_vals' u64 values.  The number
1724  * of vals must match the number of field in the synthetic event, and
1725  * must be in the same order as the synthetic event fields.
1726  *
1727  * All vals should be cast to u64, and string vals are just pointers
1728  * to strings, cast to u64.  Strings will be copied into space
1729  * reserved in the event for the string, using these pointers.
1730  *
1731  * Return: 0 on success, err otherwise.
1732  */
1733 int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1734 {
1735         unsigned int i, n_u64, len, data_size = 0;
1736         struct synth_event_trace_state state;
1737         va_list args;
1738         int ret;
1739
1740         ret = __synth_event_trace_init(file, &state);
1741         if (ret) {
1742                 if (ret == -ENOENT)
1743                         ret = 0; /* just disabled, not really an error */
1744                 return ret;
1745         }
1746
1747         if (state.event->n_dynamic_fields) {
1748                 va_start(args, n_vals);
1749
1750                 for (i = 0; i < state.event->n_fields; i++) {
1751                         u64 val = va_arg(args, u64);
1752
1753                         if (state.event->fields[i]->is_string &&
1754                             state.event->fields[i]->is_dynamic) {
1755                                 char *str_val = (char *)(long)val;
1756
1757                                 data_size += strlen(str_val) + 1;
1758                         }
1759                 }
1760
1761                 va_end(args);
1762         }
1763
1764         ret = __synth_event_trace_start(file, &state, data_size);
1765         if (ret)
1766                 return ret;
1767
1768         if (n_vals != state.event->n_fields) {
1769                 ret = -EINVAL;
1770                 goto out;
1771         }
1772
1773         data_size = 0;
1774
1775         va_start(args, n_vals);
1776         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1777                 u64 val;
1778
1779                 val = va_arg(args, u64);
1780
1781                 if (state.event->fields[i]->is_string) {
1782                         char *str_val = (char *)(long)val;
1783
1784                         len = trace_string(state.entry, state.event, str_val,
1785                                            state.event->fields[i]->is_dynamic,
1786                                            data_size, &n_u64);
1787                         data_size += len; /* only dynamic string increments */
1788                 } else {
1789                         struct synth_field *field = state.event->fields[i];
1790
1791                         switch (field->size) {
1792                         case 1:
1793                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1794                                 break;
1795
1796                         case 2:
1797                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1798                                 break;
1799
1800                         case 4:
1801                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1802                                 break;
1803
1804                         default:
1805                                 state.entry->fields[n_u64] = val;
1806                                 break;
1807                         }
1808                         n_u64++;
1809                 }
1810         }
1811         va_end(args);
1812 out:
1813         __synth_event_trace_end(&state);
1814
1815         return ret;
1816 }
1817 EXPORT_SYMBOL_GPL(synth_event_trace);
1818
1819 /**
1820  * synth_event_trace_array - Trace a synthetic event from an array
1821  * @file: The trace_event_file representing the synthetic event
1822  * @vals: Array of values
1823  * @n_vals: The number of values in vals
1824  *
1825  * Trace a synthetic event using the values passed in as 'vals'.
1826  *
1827  * The 'vals' array is just an array of 'n_vals' u64.  The number of
1828  * vals must match the number of field in the synthetic event, and
1829  * must be in the same order as the synthetic event fields.
1830  *
1831  * All vals should be cast to u64, and string vals are just pointers
1832  * to strings, cast to u64.  Strings will be copied into space
1833  * reserved in the event for the string, using these pointers.
1834  *
1835  * Return: 0 on success, err otherwise.
1836  */
1837 int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1838                             unsigned int n_vals)
1839 {
1840         unsigned int i, n_u64, field_pos, len, data_size = 0;
1841         struct synth_event_trace_state state;
1842         char *str_val;
1843         int ret;
1844
1845         ret = __synth_event_trace_init(file, &state);
1846         if (ret) {
1847                 if (ret == -ENOENT)
1848                         ret = 0; /* just disabled, not really an error */
1849                 return ret;
1850         }
1851
1852         if (state.event->n_dynamic_fields) {
1853                 for (i = 0; i < state.event->n_dynamic_fields; i++) {
1854                         field_pos = state.event->dynamic_fields[i]->field_pos;
1855                         str_val = (char *)(long)vals[field_pos];
1856                         len = strlen(str_val) + 1;
1857                         data_size += len;
1858                 }
1859         }
1860
1861         ret = __synth_event_trace_start(file, &state, data_size);
1862         if (ret)
1863                 return ret;
1864
1865         if (n_vals != state.event->n_fields) {
1866                 ret = -EINVAL;
1867                 goto out;
1868         }
1869
1870         data_size = 0;
1871
1872         for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1873                 if (state.event->fields[i]->is_string) {
1874                         char *str_val = (char *)(long)vals[i];
1875
1876                         len = trace_string(state.entry, state.event, str_val,
1877                                            state.event->fields[i]->is_dynamic,
1878                                            data_size, &n_u64);
1879                         data_size += len; /* only dynamic string increments */
1880                 } else {
1881                         struct synth_field *field = state.event->fields[i];
1882                         u64 val = vals[i];
1883
1884                         switch (field->size) {
1885                         case 1:
1886                                 *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1887                                 break;
1888
1889                         case 2:
1890                                 *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1891                                 break;
1892
1893                         case 4:
1894                                 *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1895                                 break;
1896
1897                         default:
1898                                 state.entry->fields[n_u64] = val;
1899                                 break;
1900                         }
1901                         n_u64++;
1902                 }
1903         }
1904 out:
1905         __synth_event_trace_end(&state);
1906
1907         return ret;
1908 }
1909 EXPORT_SYMBOL_GPL(synth_event_trace_array);
1910
1911 /**
1912  * synth_event_trace_start - Start piecewise synthetic event trace
1913  * @file: The trace_event_file representing the synthetic event
1914  * @trace_state: A pointer to object tracking the piecewise trace state
1915  *
1916  * Start the trace of a synthetic event field-by-field rather than all
1917  * at once.
1918  *
1919  * This function 'opens' an event trace, which means space is reserved
1920  * for the event in the trace buffer, after which the event's
1921  * individual field values can be set through either
1922  * synth_event_add_next_val() or synth_event_add_val().
1923  *
1924  * A pointer to a trace_state object is passed in, which will keep
1925  * track of the current event trace state until the event trace is
1926  * closed (and the event finally traced) using
1927  * synth_event_trace_end().
1928  *
1929  * Note that synth_event_trace_end() must be called after all values
1930  * have been added for each event trace, regardless of whether adding
1931  * all field values succeeded or not.
1932  *
1933  * Note also that for a given event trace, all fields must be added
1934  * using either synth_event_add_next_val() or synth_event_add_val()
1935  * but not both together or interleaved.
1936  *
1937  * Return: 0 on success, err otherwise.
1938  */
1939 int synth_event_trace_start(struct trace_event_file *file,
1940                             struct synth_event_trace_state *trace_state)
1941 {
1942         int ret;
1943
1944         if (!trace_state)
1945                 return -EINVAL;
1946
1947         ret = __synth_event_trace_init(file, trace_state);
1948         if (ret) {
1949                 if (ret == -ENOENT)
1950                         ret = 0; /* just disabled, not really an error */
1951                 return ret;
1952         }
1953
1954         if (trace_state->event->n_dynamic_fields)
1955                 return -ENOTSUPP;
1956
1957         ret = __synth_event_trace_start(file, trace_state, 0);
1958
1959         return ret;
1960 }
1961 EXPORT_SYMBOL_GPL(synth_event_trace_start);
1962
1963 static int __synth_event_add_val(const char *field_name, u64 val,
1964                                  struct synth_event_trace_state *trace_state)
1965 {
1966         struct synth_field *field = NULL;
1967         struct synth_trace_event *entry;
1968         struct synth_event *event;
1969         int i, ret = 0;
1970
1971         if (!trace_state) {
1972                 ret = -EINVAL;
1973                 goto out;
1974         }
1975
1976         /* can't mix add_next_synth_val() with add_synth_val() */
1977         if (field_name) {
1978                 if (trace_state->add_next) {
1979                         ret = -EINVAL;
1980                         goto out;
1981                 }
1982                 trace_state->add_name = true;
1983         } else {
1984                 if (trace_state->add_name) {
1985                         ret = -EINVAL;
1986                         goto out;
1987                 }
1988                 trace_state->add_next = true;
1989         }
1990
1991         if (trace_state->disabled)
1992                 goto out;
1993
1994         event = trace_state->event;
1995         if (trace_state->add_name) {
1996                 for (i = 0; i < event->n_fields; i++) {
1997                         field = event->fields[i];
1998                         if (strcmp(field->name, field_name) == 0)
1999                                 break;
2000                 }
2001                 if (!field) {
2002                         ret = -EINVAL;
2003                         goto out;
2004                 }
2005         } else {
2006                 if (trace_state->cur_field >= event->n_fields) {
2007                         ret = -EINVAL;
2008                         goto out;
2009                 }
2010                 field = event->fields[trace_state->cur_field++];
2011         }
2012
2013         entry = trace_state->entry;
2014         if (field->is_string) {
2015                 char *str_val = (char *)(long)val;
2016                 char *str_field;
2017
2018                 if (field->is_dynamic) { /* add_val can't do dynamic strings */
2019                         ret = -EINVAL;
2020                         goto out;
2021                 }
2022
2023                 if (!str_val) {
2024                         ret = -EINVAL;
2025                         goto out;
2026                 }
2027
2028                 str_field = (char *)&entry->fields[field->offset];
2029                 strscpy(str_field, str_val, STR_VAR_LEN_MAX);
2030         } else {
2031                 switch (field->size) {
2032                 case 1:
2033                         *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
2034                         break;
2035
2036                 case 2:
2037                         *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
2038                         break;
2039
2040                 case 4:
2041                         *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
2042                         break;
2043
2044                 default:
2045                         trace_state->entry->fields[field->offset] = val;
2046                         break;
2047                 }
2048         }
2049  out:
2050         return ret;
2051 }
2052
2053 /**
2054  * synth_event_add_next_val - Add the next field's value to an open synth trace
2055  * @val: The value to set the next field to
2056  * @trace_state: A pointer to object tracking the piecewise trace state
2057  *
2058  * Set the value of the next field in an event that's been opened by
2059  * synth_event_trace_start().
2060  *
2061  * The val param should be the value cast to u64.  If the value points
2062  * to a string, the val param should be a char * cast to u64.
2063  *
2064  * This function assumes all the fields in an event are to be set one
2065  * after another - successive calls to this function are made, one for
2066  * each field, in the order of the fields in the event, until all
2067  * fields have been set.  If you'd rather set each field individually
2068  * without regard to ordering, synth_event_add_val() can be used
2069  * instead.
2070  *
2071  * Note however that synth_event_add_next_val() and
2072  * synth_event_add_val() can't be intermixed for a given event trace -
2073  * one or the other but not both can be used at the same time.
2074  *
2075  * Note also that synth_event_trace_end() must be called after all
2076  * values have been added for each event trace, regardless of whether
2077  * adding all field values succeeded or not.
2078  *
2079  * Return: 0 on success, err otherwise.
2080  */
2081 int synth_event_add_next_val(u64 val,
2082                              struct synth_event_trace_state *trace_state)
2083 {
2084         return __synth_event_add_val(NULL, val, trace_state);
2085 }
2086 EXPORT_SYMBOL_GPL(synth_event_add_next_val);
2087
2088 /**
2089  * synth_event_add_val - Add a named field's value to an open synth trace
2090  * @field_name: The name of the synthetic event field value to set
2091  * @val: The value to set the named field to
2092  * @trace_state: A pointer to object tracking the piecewise trace state
2093  *
2094  * Set the value of the named field in an event that's been opened by
2095  * synth_event_trace_start().
2096  *
2097  * The val param should be the value cast to u64.  If the value points
2098  * to a string, the val param should be a char * cast to u64.
2099  *
2100  * This function looks up the field name, and if found, sets the field
2101  * to the specified value.  This lookup makes this function more
2102  * expensive than synth_event_add_next_val(), so use that or the
2103  * none-piecewise synth_event_trace() instead if efficiency is more
2104  * important.
2105  *
2106  * Note however that synth_event_add_next_val() and
2107  * synth_event_add_val() can't be intermixed for a given event trace -
2108  * one or the other but not both can be used at the same time.
2109  *
2110  * Note also that synth_event_trace_end() must be called after all
2111  * values have been added for each event trace, regardless of whether
2112  * adding all field values succeeded or not.
2113  *
2114  * Return: 0 on success, err otherwise.
2115  */
2116 int synth_event_add_val(const char *field_name, u64 val,
2117                         struct synth_event_trace_state *trace_state)
2118 {
2119         return __synth_event_add_val(field_name, val, trace_state);
2120 }
2121 EXPORT_SYMBOL_GPL(synth_event_add_val);
2122
2123 /**
2124  * synth_event_trace_end - End piecewise synthetic event trace
2125  * @trace_state: A pointer to object tracking the piecewise trace state
2126  *
2127  * End the trace of a synthetic event opened by
2128  * synth_event_trace__start().
2129  *
2130  * This function 'closes' an event trace, which basically means that
2131  * it commits the reserved event and cleans up other loose ends.
2132  *
2133  * A pointer to a trace_state object is passed in, which will keep
2134  * track of the current event trace state opened with
2135  * synth_event_trace_start().
2136  *
2137  * Note that this function must be called after all values have been
2138  * added for each event trace, regardless of whether adding all field
2139  * values succeeded or not.
2140  *
2141  * Return: 0 on success, err otherwise.
2142  */
2143 int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2144 {
2145         if (!trace_state)
2146                 return -EINVAL;
2147
2148         __synth_event_trace_end(trace_state);
2149
2150         return 0;
2151 }
2152 EXPORT_SYMBOL_GPL(synth_event_trace_end);
2153
2154 static int create_synth_event(const char *raw_command)
2155 {
2156         char *fields, *p;
2157         const char *name;
2158         int len, ret = 0;
2159
2160         raw_command = skip_spaces(raw_command);
2161         if (raw_command[0] == '\0')
2162                 return ret;
2163
2164         last_cmd_set(raw_command);
2165
2166         name = raw_command;
2167
2168         /* Don't try to process if not our system */
2169         if (name[0] != 's' || name[1] != ':')
2170                 return -ECANCELED;
2171         name += 2;
2172
2173         p = strpbrk(raw_command, " \t");
2174         if (!p) {
2175                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2176                 return -EINVAL;
2177         }
2178
2179         fields = skip_spaces(p);
2180
2181         /* This interface accepts group name prefix */
2182         if (strchr(name, '/')) {
2183                 len = str_has_prefix(name, SYNTH_SYSTEM "/");
2184                 if (len == 0) {
2185                         synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2186                         return -EINVAL;
2187                 }
2188                 name += len;
2189         }
2190
2191         len = name - raw_command;
2192
2193         ret = check_command(raw_command + len);
2194         if (ret) {
2195                 synth_err(SYNTH_ERR_INVALID_CMD, 0);
2196                 return ret;
2197         }
2198
2199         name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2200         if (!name)
2201                 return -ENOMEM;
2202
2203         ret = __create_synth_event(name, fields);
2204
2205         kfree(name);
2206
2207         return ret;
2208 }
2209
2210 static int synth_event_release(struct dyn_event *ev)
2211 {
2212         struct synth_event *event = to_synth_event(ev);
2213         int ret;
2214
2215         if (event->ref)
2216                 return -EBUSY;
2217
2218         if (trace_event_dyn_busy(&event->call))
2219                 return -EBUSY;
2220
2221         ret = unregister_synth_event(event);
2222         if (ret)
2223                 return ret;
2224
2225         dyn_event_remove(ev);
2226         free_synth_event(event);
2227         return 0;
2228 }
2229
2230 static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2231 {
2232         struct synth_field *field;
2233         unsigned int i;
2234         char *type, *t;
2235
2236         seq_printf(m, "%s\t", event->name);
2237
2238         for (i = 0; i < event->n_fields; i++) {
2239                 field = event->fields[i];
2240
2241                 type = field->type;
2242                 t = strstr(type, "__data_loc");
2243                 if (t) { /* __data_loc belongs in format but not event desc */
2244                         t += sizeof("__data_loc");
2245                         type = t;
2246                 }
2247
2248                 /* parameter values */
2249                 seq_printf(m, "%s %s%s", type, field->name,
2250                            i == event->n_fields - 1 ? "" : "; ");
2251         }
2252
2253         seq_putc(m, '\n');
2254
2255         return 0;
2256 }
2257
2258 static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2259 {
2260         struct synth_event *event = to_synth_event(ev);
2261
2262         seq_printf(m, "s:%s/", event->class.system);
2263
2264         return __synth_event_show(m, event);
2265 }
2266
2267 static int synth_events_seq_show(struct seq_file *m, void *v)
2268 {
2269         struct dyn_event *ev = v;
2270
2271         if (!is_synth_event(ev))
2272                 return 0;
2273
2274         return __synth_event_show(m, to_synth_event(ev));
2275 }
2276
2277 static const struct seq_operations synth_events_seq_op = {
2278         .start  = dyn_event_seq_start,
2279         .next   = dyn_event_seq_next,
2280         .stop   = dyn_event_seq_stop,
2281         .show   = synth_events_seq_show,
2282 };
2283
2284 static int synth_events_open(struct inode *inode, struct file *file)
2285 {
2286         int ret;
2287
2288         ret = security_locked_down(LOCKDOWN_TRACEFS);
2289         if (ret)
2290                 return ret;
2291
2292         if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2293                 ret = dyn_events_release_all(&synth_event_ops);
2294                 if (ret < 0)
2295                         return ret;
2296         }
2297
2298         return seq_open(file, &synth_events_seq_op);
2299 }
2300
2301 static ssize_t synth_events_write(struct file *file,
2302                                   const char __user *buffer,
2303                                   size_t count, loff_t *ppos)
2304 {
2305         return trace_parse_run_command(file, buffer, count, ppos,
2306                                        create_or_delete_synth_event);
2307 }
2308
2309 static const struct file_operations synth_events_fops = {
2310         .open           = synth_events_open,
2311         .write          = synth_events_write,
2312         .read           = seq_read,
2313         .llseek         = seq_lseek,
2314         .release        = seq_release,
2315 };
2316
2317 /*
2318  * Register dynevent at core_initcall. This allows kernel to setup kprobe
2319  * events in postcore_initcall without tracefs.
2320  */
2321 static __init int trace_events_synth_init_early(void)
2322 {
2323         int err = 0;
2324
2325         err = dyn_event_register(&synth_event_ops);
2326         if (err)
2327                 pr_warn("Could not register synth_event_ops\n");
2328
2329         return err;
2330 }
2331 core_initcall(trace_events_synth_init_early);
2332
2333 static __init int trace_events_synth_init(void)
2334 {
2335         struct dentry *entry = NULL;
2336         int err = 0;
2337         err = tracing_init_dentry();
2338         if (err)
2339                 goto err;
2340
2341         entry = tracefs_create_file("synthetic_events", TRACE_MODE_WRITE,
2342                                     NULL, NULL, &synth_events_fops);
2343         if (!entry) {
2344                 err = -ENODEV;
2345                 goto err;
2346         }
2347
2348         return err;
2349  err:
2350         pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2351
2352         return err;
2353 }
2354
2355 fs_initcall(trace_events_synth_init);