linux/kernel/trace/trace_events_synth.c
<<
>>
Prefs
   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(INVALID_CMD,          "Command must be of the form: <name> field[;field] ..."),\
  27        C(INVALID_DYN_CMD,      "Command must be of the form: s or -:[synthetic/]<name> field[;field] ..."),\
  28        C(EVENT_EXISTS,         "Event already exists"),        \
  29        C(TOO_MANY_FIELDS,      "Too many fields"),             \
  30        C(INCOMPLETE_TYPE,      "Incomplete type"),             \
  31        C(INVALID_TYPE,         "Invalid type"),                \
  32        C(INVALID_FIELD,        "Invalid field"),               \
  33        C(INVALID_ARRAY_SPEC,   "Invalid array specification"),
  34
  35#undef C
  36#define C(a, b)         SYNTH_ERR_##a
  37
  38enum { ERRORS };
  39
  40#undef C
  41#define C(a, b)         b
  42
  43static const char *err_text[] = { ERRORS };
  44
  45static char last_cmd[MAX_FILTER_STR_VAL];
  46
  47static int errpos(const char *str)
  48{
  49        return err_pos(last_cmd, str);
  50}
  51
  52static void last_cmd_set(const char *str)
  53{
  54        if (!str)
  55                return;
  56
  57        strncpy(last_cmd, str, MAX_FILTER_STR_VAL - 1);
  58}
  59
  60static void synth_err(u8 err_type, u8 err_pos)
  61{
  62        tracing_log_err(NULL, "synthetic_events", last_cmd, err_text,
  63                        err_type, err_pos);
  64}
  65
  66static int create_synth_event(const char *raw_command);
  67static int synth_event_show(struct seq_file *m, struct dyn_event *ev);
  68static int synth_event_release(struct dyn_event *ev);
  69static bool synth_event_is_busy(struct dyn_event *ev);
  70static bool synth_event_match(const char *system, const char *event,
  71                        int argc, const char **argv, struct dyn_event *ev);
  72
  73static struct dyn_event_operations synth_event_ops = {
  74        .create = create_synth_event,
  75        .show = synth_event_show,
  76        .is_busy = synth_event_is_busy,
  77        .free = synth_event_release,
  78        .match = synth_event_match,
  79};
  80
  81static bool is_synth_event(struct dyn_event *ev)
  82{
  83        return ev->ops == &synth_event_ops;
  84}
  85
  86static struct synth_event *to_synth_event(struct dyn_event *ev)
  87{
  88        return container_of(ev, struct synth_event, devent);
  89}
  90
  91static bool synth_event_is_busy(struct dyn_event *ev)
  92{
  93        struct synth_event *event = to_synth_event(ev);
  94
  95        return event->ref != 0;
  96}
  97
  98static bool synth_event_match(const char *system, const char *event,
  99                        int argc, const char **argv, struct dyn_event *ev)
 100{
 101        struct synth_event *sev = to_synth_event(ev);
 102
 103        return strcmp(sev->name, event) == 0 &&
 104                (!system || strcmp(system, SYNTH_SYSTEM) == 0);
 105}
 106
 107struct synth_trace_event {
 108        struct trace_entry      ent;
 109        u64                     fields[];
 110};
 111
 112static int synth_event_define_fields(struct trace_event_call *call)
 113{
 114        struct synth_trace_event trace;
 115        int offset = offsetof(typeof(trace), fields);
 116        struct synth_event *event = call->data;
 117        unsigned int i, size, n_u64;
 118        char *name, *type;
 119        bool is_signed;
 120        int ret = 0;
 121
 122        for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 123                size = event->fields[i]->size;
 124                is_signed = event->fields[i]->is_signed;
 125                type = event->fields[i]->type;
 126                name = event->fields[i]->name;
 127                ret = trace_define_field(call, type, name, offset, size,
 128                                         is_signed, FILTER_OTHER);
 129                if (ret)
 130                        break;
 131
 132                event->fields[i]->offset = n_u64;
 133
 134                if (event->fields[i]->is_string && !event->fields[i]->is_dynamic) {
 135                        offset += STR_VAR_LEN_MAX;
 136                        n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 137                } else {
 138                        offset += sizeof(u64);
 139                        n_u64++;
 140                }
 141        }
 142
 143        event->n_u64 = n_u64;
 144
 145        return ret;
 146}
 147
 148static bool synth_field_signed(char *type)
 149{
 150        if (str_has_prefix(type, "u"))
 151                return false;
 152        if (strcmp(type, "gfp_t") == 0)
 153                return false;
 154
 155        return true;
 156}
 157
 158static int synth_field_is_string(char *type)
 159{
 160        if (strstr(type, "char[") != NULL)
 161                return true;
 162
 163        return false;
 164}
 165
 166static int synth_field_string_size(char *type)
 167{
 168        char buf[4], *end, *start;
 169        unsigned int len;
 170        int size, err;
 171
 172        start = strstr(type, "char[");
 173        if (start == NULL)
 174                return -EINVAL;
 175        start += sizeof("char[") - 1;
 176
 177        end = strchr(type, ']');
 178        if (!end || end < start || type + strlen(type) > end + 1)
 179                return -EINVAL;
 180
 181        len = end - start;
 182        if (len > 3)
 183                return -EINVAL;
 184
 185        if (len == 0)
 186                return 0; /* variable-length string */
 187
 188        strncpy(buf, start, len);
 189        buf[len] = '\0';
 190
 191        err = kstrtouint(buf, 0, &size);
 192        if (err)
 193                return err;
 194
 195        if (size > STR_VAR_LEN_MAX)
 196                return -EINVAL;
 197
 198        return size;
 199}
 200
 201static int synth_field_size(char *type)
 202{
 203        int size = 0;
 204
 205        if (strcmp(type, "s64") == 0)
 206                size = sizeof(s64);
 207        else if (strcmp(type, "u64") == 0)
 208                size = sizeof(u64);
 209        else if (strcmp(type, "s32") == 0)
 210                size = sizeof(s32);
 211        else if (strcmp(type, "u32") == 0)
 212                size = sizeof(u32);
 213        else if (strcmp(type, "s16") == 0)
 214                size = sizeof(s16);
 215        else if (strcmp(type, "u16") == 0)
 216                size = sizeof(u16);
 217        else if (strcmp(type, "s8") == 0)
 218                size = sizeof(s8);
 219        else if (strcmp(type, "u8") == 0)
 220                size = sizeof(u8);
 221        else if (strcmp(type, "char") == 0)
 222                size = sizeof(char);
 223        else if (strcmp(type, "unsigned char") == 0)
 224                size = sizeof(unsigned char);
 225        else if (strcmp(type, "int") == 0)
 226                size = sizeof(int);
 227        else if (strcmp(type, "unsigned int") == 0)
 228                size = sizeof(unsigned int);
 229        else if (strcmp(type, "long") == 0)
 230                size = sizeof(long);
 231        else if (strcmp(type, "unsigned long") == 0)
 232                size = sizeof(unsigned long);
 233        else if (strcmp(type, "bool") == 0)
 234                size = sizeof(bool);
 235        else if (strcmp(type, "pid_t") == 0)
 236                size = sizeof(pid_t);
 237        else if (strcmp(type, "gfp_t") == 0)
 238                size = sizeof(gfp_t);
 239        else if (synth_field_is_string(type))
 240                size = synth_field_string_size(type);
 241
 242        return size;
 243}
 244
 245static const char *synth_field_fmt(char *type)
 246{
 247        const char *fmt = "%llu";
 248
 249        if (strcmp(type, "s64") == 0)
 250                fmt = "%lld";
 251        else if (strcmp(type, "u64") == 0)
 252                fmt = "%llu";
 253        else if (strcmp(type, "s32") == 0)
 254                fmt = "%d";
 255        else if (strcmp(type, "u32") == 0)
 256                fmt = "%u";
 257        else if (strcmp(type, "s16") == 0)
 258                fmt = "%d";
 259        else if (strcmp(type, "u16") == 0)
 260                fmt = "%u";
 261        else if (strcmp(type, "s8") == 0)
 262                fmt = "%d";
 263        else if (strcmp(type, "u8") == 0)
 264                fmt = "%u";
 265        else if (strcmp(type, "char") == 0)
 266                fmt = "%d";
 267        else if (strcmp(type, "unsigned char") == 0)
 268                fmt = "%u";
 269        else if (strcmp(type, "int") == 0)
 270                fmt = "%d";
 271        else if (strcmp(type, "unsigned int") == 0)
 272                fmt = "%u";
 273        else if (strcmp(type, "long") == 0)
 274                fmt = "%ld";
 275        else if (strcmp(type, "unsigned long") == 0)
 276                fmt = "%lu";
 277        else if (strcmp(type, "bool") == 0)
 278                fmt = "%d";
 279        else if (strcmp(type, "pid_t") == 0)
 280                fmt = "%d";
 281        else if (strcmp(type, "gfp_t") == 0)
 282                fmt = "%x";
 283        else if (synth_field_is_string(type))
 284                fmt = "%.*s";
 285
 286        return fmt;
 287}
 288
 289static void print_synth_event_num_val(struct trace_seq *s,
 290                                      char *print_fmt, char *name,
 291                                      int size, u64 val, char *space)
 292{
 293        switch (size) {
 294        case 1:
 295                trace_seq_printf(s, print_fmt, name, (u8)val, space);
 296                break;
 297
 298        case 2:
 299                trace_seq_printf(s, print_fmt, name, (u16)val, space);
 300                break;
 301
 302        case 4:
 303                trace_seq_printf(s, print_fmt, name, (u32)val, space);
 304                break;
 305
 306        default:
 307                trace_seq_printf(s, print_fmt, name, val, space);
 308                break;
 309        }
 310}
 311
 312static enum print_line_t print_synth_event(struct trace_iterator *iter,
 313                                           int flags,
 314                                           struct trace_event *event)
 315{
 316        struct trace_array *tr = iter->tr;
 317        struct trace_seq *s = &iter->seq;
 318        struct synth_trace_event *entry;
 319        struct synth_event *se;
 320        unsigned int i, n_u64;
 321        char print_fmt[32];
 322        const char *fmt;
 323
 324        entry = (struct synth_trace_event *)iter->ent;
 325        se = container_of(event, struct synth_event, call.event);
 326
 327        trace_seq_printf(s, "%s: ", se->name);
 328
 329        for (i = 0, n_u64 = 0; i < se->n_fields; i++) {
 330                if (trace_seq_has_overflowed(s))
 331                        goto end;
 332
 333                fmt = synth_field_fmt(se->fields[i]->type);
 334
 335                /* parameter types */
 336                if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
 337                        trace_seq_printf(s, "%s ", fmt);
 338
 339                snprintf(print_fmt, sizeof(print_fmt), "%%s=%s%%s", fmt);
 340
 341                /* parameter values */
 342                if (se->fields[i]->is_string) {
 343                        if (se->fields[i]->is_dynamic) {
 344                                u32 offset, data_offset;
 345                                char *str_field;
 346
 347                                offset = (u32)entry->fields[n_u64];
 348                                data_offset = offset & 0xffff;
 349
 350                                str_field = (char *)entry + data_offset;
 351
 352                                trace_seq_printf(s, print_fmt, se->fields[i]->name,
 353                                                 STR_VAR_LEN_MAX,
 354                                                 str_field,
 355                                                 i == se->n_fields - 1 ? "" : " ");
 356                                n_u64++;
 357                        } else {
 358                                trace_seq_printf(s, print_fmt, se->fields[i]->name,
 359                                                 STR_VAR_LEN_MAX,
 360                                                 (char *)&entry->fields[n_u64],
 361                                                 i == se->n_fields - 1 ? "" : " ");
 362                                n_u64 += STR_VAR_LEN_MAX / sizeof(u64);
 363                        }
 364                } else {
 365                        struct trace_print_flags __flags[] = {
 366                            __def_gfpflag_names, {-1, NULL} };
 367                        char *space = (i == se->n_fields - 1 ? "" : " ");
 368
 369                        print_synth_event_num_val(s, print_fmt,
 370                                                  se->fields[i]->name,
 371                                                  se->fields[i]->size,
 372                                                  entry->fields[n_u64],
 373                                                  space);
 374
 375                        if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
 376                                trace_seq_puts(s, " (");
 377                                trace_print_flags_seq(s, "|",
 378                                                      entry->fields[n_u64],
 379                                                      __flags);
 380                                trace_seq_putc(s, ')');
 381                        }
 382                        n_u64++;
 383                }
 384        }
 385end:
 386        trace_seq_putc(s, '\n');
 387
 388        return trace_handle_return(s);
 389}
 390
 391static struct trace_event_functions synth_event_funcs = {
 392        .trace          = print_synth_event
 393};
 394
 395static unsigned int trace_string(struct synth_trace_event *entry,
 396                                 struct synth_event *event,
 397                                 char *str_val,
 398                                 bool is_dynamic,
 399                                 unsigned int data_size,
 400                                 unsigned int *n_u64)
 401{
 402        unsigned int len = 0;
 403        char *str_field;
 404
 405        if (is_dynamic) {
 406                u32 data_offset;
 407
 408                data_offset = offsetof(typeof(*entry), fields);
 409                data_offset += event->n_u64 * sizeof(u64);
 410                data_offset += data_size;
 411
 412                str_field = (char *)entry + data_offset;
 413
 414                len = strlen(str_val) + 1;
 415                strscpy(str_field, str_val, len);
 416
 417                data_offset |= len << 16;
 418                *(u32 *)&entry->fields[*n_u64] = data_offset;
 419
 420                (*n_u64)++;
 421        } else {
 422                str_field = (char *)&entry->fields[*n_u64];
 423
 424                strscpy(str_field, str_val, STR_VAR_LEN_MAX);
 425                (*n_u64) += STR_VAR_LEN_MAX / sizeof(u64);
 426        }
 427
 428        return len;
 429}
 430
 431static notrace void trace_event_raw_event_synth(void *__data,
 432                                                u64 *var_ref_vals,
 433                                                unsigned int *var_ref_idx)
 434{
 435        unsigned int i, n_u64, val_idx, len, data_size = 0;
 436        struct trace_event_file *trace_file = __data;
 437        struct synth_trace_event *entry;
 438        struct trace_event_buffer fbuffer;
 439        struct trace_buffer *buffer;
 440        struct synth_event *event;
 441        int fields_size = 0;
 442
 443        event = trace_file->event_call->data;
 444
 445        if (trace_trigger_soft_disabled(trace_file))
 446                return;
 447
 448        fields_size = event->n_u64 * sizeof(u64);
 449
 450        for (i = 0; i < event->n_dynamic_fields; i++) {
 451                unsigned int field_pos = event->dynamic_fields[i]->field_pos;
 452                char *str_val;
 453
 454                val_idx = var_ref_idx[field_pos];
 455                str_val = (char *)(long)var_ref_vals[val_idx];
 456
 457                len = strlen(str_val) + 1;
 458
 459                fields_size += len;
 460        }
 461
 462        /*
 463         * Avoid ring buffer recursion detection, as this event
 464         * is being performed within another event.
 465         */
 466        buffer = trace_file->tr->array_buffer.buffer;
 467        ring_buffer_nest_start(buffer);
 468
 469        entry = trace_event_buffer_reserve(&fbuffer, trace_file,
 470                                           sizeof(*entry) + fields_size);
 471        if (!entry)
 472                goto out;
 473
 474        for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
 475                val_idx = var_ref_idx[i];
 476                if (event->fields[i]->is_string) {
 477                        char *str_val = (char *)(long)var_ref_vals[val_idx];
 478
 479                        len = trace_string(entry, event, str_val,
 480                                           event->fields[i]->is_dynamic,
 481                                           data_size, &n_u64);
 482                        data_size += len; /* only dynamic string increments */
 483                } else {
 484                        struct synth_field *field = event->fields[i];
 485                        u64 val = var_ref_vals[val_idx];
 486
 487                        switch (field->size) {
 488                        case 1:
 489                                *(u8 *)&entry->fields[n_u64] = (u8)val;
 490                                break;
 491
 492                        case 2:
 493                                *(u16 *)&entry->fields[n_u64] = (u16)val;
 494                                break;
 495
 496                        case 4:
 497                                *(u32 *)&entry->fields[n_u64] = (u32)val;
 498                                break;
 499
 500                        default:
 501                                entry->fields[n_u64] = val;
 502                                break;
 503                        }
 504                        n_u64++;
 505                }
 506        }
 507
 508        trace_event_buffer_commit(&fbuffer);
 509out:
 510        ring_buffer_nest_end(buffer);
 511}
 512
 513static void free_synth_event_print_fmt(struct trace_event_call *call)
 514{
 515        if (call) {
 516                kfree(call->print_fmt);
 517                call->print_fmt = NULL;
 518        }
 519}
 520
 521static int __set_synth_event_print_fmt(struct synth_event *event,
 522                                       char *buf, int len)
 523{
 524        const char *fmt;
 525        int pos = 0;
 526        int i;
 527
 528        /* When len=0, we just calculate the needed length */
 529#define LEN_OR_ZERO (len ? len - pos : 0)
 530
 531        pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 532        for (i = 0; i < event->n_fields; i++) {
 533                fmt = synth_field_fmt(event->fields[i]->type);
 534                pos += snprintf(buf + pos, LEN_OR_ZERO, "%s=%s%s",
 535                                event->fields[i]->name, fmt,
 536                                i == event->n_fields - 1 ? "" : ", ");
 537        }
 538        pos += snprintf(buf + pos, LEN_OR_ZERO, "\"");
 539
 540        for (i = 0; i < event->n_fields; i++) {
 541                if (event->fields[i]->is_string &&
 542                    event->fields[i]->is_dynamic)
 543                        pos += snprintf(buf + pos, LEN_OR_ZERO,
 544                                ", __get_str(%s)", event->fields[i]->name);
 545                else
 546                        pos += snprintf(buf + pos, LEN_OR_ZERO,
 547                                        ", REC->%s", event->fields[i]->name);
 548        }
 549
 550#undef LEN_OR_ZERO
 551
 552        /* return the length of print_fmt */
 553        return pos;
 554}
 555
 556static int set_synth_event_print_fmt(struct trace_event_call *call)
 557{
 558        struct synth_event *event = call->data;
 559        char *print_fmt;
 560        int len;
 561
 562        /* First: called with 0 length to calculate the needed length */
 563        len = __set_synth_event_print_fmt(event, NULL, 0);
 564
 565        print_fmt = kmalloc(len + 1, GFP_KERNEL);
 566        if (!print_fmt)
 567                return -ENOMEM;
 568
 569        /* Second: actually write the @print_fmt */
 570        __set_synth_event_print_fmt(event, print_fmt, len + 1);
 571        call->print_fmt = print_fmt;
 572
 573        return 0;
 574}
 575
 576static void free_synth_field(struct synth_field *field)
 577{
 578        kfree(field->type);
 579        kfree(field->name);
 580        kfree(field);
 581}
 582
 583static int check_field_version(const char *prefix, const char *field_type,
 584                               const char *field_name)
 585{
 586        /*
 587         * For backward compatibility, the old synthetic event command
 588         * format did not require semicolons, and in order to not
 589         * break user space, that old format must still work. If a new
 590         * feature is added, then the format that uses the new feature
 591         * will be required to have semicolons, as nothing that uses
 592         * the old format would be using the new, yet to be created,
 593         * feature. When a new feature is added, this will detect it,
 594         * and return a number greater than 1, and require the format
 595         * to use semicolons.
 596         */
 597        return 1;
 598}
 599
 600static struct synth_field *parse_synth_field(int argc, char **argv,
 601                                             int *consumed, int *field_version)
 602{
 603        const char *prefix = NULL, *field_type = argv[0], *field_name, *array;
 604        struct synth_field *field;
 605        int len, ret = -ENOMEM;
 606        struct seq_buf s;
 607        ssize_t size;
 608
 609        if (!strcmp(field_type, "unsigned")) {
 610                if (argc < 3) {
 611                        synth_err(SYNTH_ERR_INCOMPLETE_TYPE, errpos(field_type));
 612                        return ERR_PTR(-EINVAL);
 613                }
 614                prefix = "unsigned ";
 615                field_type = argv[1];
 616                field_name = argv[2];
 617                *consumed += 3;
 618        } else {
 619                field_name = argv[1];
 620                *consumed += 2;
 621        }
 622
 623        if (!field_name) {
 624                synth_err(SYNTH_ERR_INVALID_FIELD, errpos(field_type));
 625                return ERR_PTR(-EINVAL);
 626        }
 627
 628        *field_version = check_field_version(prefix, field_type, field_name);
 629
 630        field = kzalloc(sizeof(*field), GFP_KERNEL);
 631        if (!field)
 632                return ERR_PTR(-ENOMEM);
 633
 634        len = strlen(field_name);
 635        array = strchr(field_name, '[');
 636        if (array)
 637                len -= strlen(array);
 638
 639        field->name = kmemdup_nul(field_name, len, GFP_KERNEL);
 640        if (!field->name)
 641                goto free;
 642
 643        if (!is_good_name(field->name)) {
 644                synth_err(SYNTH_ERR_BAD_NAME, errpos(field_name));
 645                ret = -EINVAL;
 646                goto free;
 647        }
 648
 649        len = strlen(field_type) + 1;
 650
 651        if (array)
 652                len += strlen(array);
 653
 654        if (prefix)
 655                len += strlen(prefix);
 656
 657        field->type = kzalloc(len, GFP_KERNEL);
 658        if (!field->type)
 659                goto free;
 660
 661        seq_buf_init(&s, field->type, len);
 662        if (prefix)
 663                seq_buf_puts(&s, prefix);
 664        seq_buf_puts(&s, field_type);
 665        if (array)
 666                seq_buf_puts(&s, array);
 667        if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 668                goto free;
 669
 670        s.buffer[s.len] = '\0';
 671
 672        size = synth_field_size(field->type);
 673        if (size < 0) {
 674                if (array)
 675                        synth_err(SYNTH_ERR_INVALID_ARRAY_SPEC, errpos(field_name));
 676                else
 677                        synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 678                ret = -EINVAL;
 679                goto free;
 680        } else if (size == 0) {
 681                if (synth_field_is_string(field->type)) {
 682                        char *type;
 683
 684                        len = sizeof("__data_loc ") + strlen(field->type) + 1;
 685                        type = kzalloc(len, GFP_KERNEL);
 686                        if (!type)
 687                                goto free;
 688
 689                        seq_buf_init(&s, type, len);
 690                        seq_buf_puts(&s, "__data_loc ");
 691                        seq_buf_puts(&s, field->type);
 692
 693                        if (WARN_ON_ONCE(!seq_buf_buffer_left(&s)))
 694                                goto free;
 695                        s.buffer[s.len] = '\0';
 696
 697                        kfree(field->type);
 698                        field->type = type;
 699
 700                        field->is_dynamic = true;
 701                        size = sizeof(u64);
 702                } else {
 703                        synth_err(SYNTH_ERR_INVALID_TYPE, errpos(field_type));
 704                        ret = -EINVAL;
 705                        goto free;
 706                }
 707        }
 708        field->size = size;
 709
 710        if (synth_field_is_string(field->type))
 711                field->is_string = true;
 712
 713        field->is_signed = synth_field_signed(field->type);
 714 out:
 715        return field;
 716 free:
 717        free_synth_field(field);
 718        field = ERR_PTR(ret);
 719        goto out;
 720}
 721
 722static void free_synth_tracepoint(struct tracepoint *tp)
 723{
 724        if (!tp)
 725                return;
 726
 727        kfree(tp->name);
 728        kfree(tp);
 729}
 730
 731static struct tracepoint *alloc_synth_tracepoint(char *name)
 732{
 733        struct tracepoint *tp;
 734
 735        tp = kzalloc(sizeof(*tp), GFP_KERNEL);
 736        if (!tp)
 737                return ERR_PTR(-ENOMEM);
 738
 739        tp->name = kstrdup(name, GFP_KERNEL);
 740        if (!tp->name) {
 741                kfree(tp);
 742                return ERR_PTR(-ENOMEM);
 743        }
 744
 745        return tp;
 746}
 747
 748struct synth_event *find_synth_event(const char *name)
 749{
 750        struct dyn_event *pos;
 751        struct synth_event *event;
 752
 753        for_each_dyn_event(pos) {
 754                if (!is_synth_event(pos))
 755                        continue;
 756                event = to_synth_event(pos);
 757                if (strcmp(event->name, name) == 0)
 758                        return event;
 759        }
 760
 761        return NULL;
 762}
 763
 764static struct trace_event_fields synth_event_fields_array[] = {
 765        { .type = TRACE_FUNCTION_TYPE,
 766          .define_fields = synth_event_define_fields },
 767        {}
 768};
 769
 770static int register_synth_event(struct synth_event *event)
 771{
 772        struct trace_event_call *call = &event->call;
 773        int ret = 0;
 774
 775        event->call.class = &event->class;
 776        event->class.system = kstrdup(SYNTH_SYSTEM, GFP_KERNEL);
 777        if (!event->class.system) {
 778                ret = -ENOMEM;
 779                goto out;
 780        }
 781
 782        event->tp = alloc_synth_tracepoint(event->name);
 783        if (IS_ERR(event->tp)) {
 784                ret = PTR_ERR(event->tp);
 785                event->tp = NULL;
 786                goto out;
 787        }
 788
 789        INIT_LIST_HEAD(&call->class->fields);
 790        call->event.funcs = &synth_event_funcs;
 791        call->class->fields_array = synth_event_fields_array;
 792
 793        ret = register_trace_event(&call->event);
 794        if (!ret) {
 795                ret = -ENODEV;
 796                goto out;
 797        }
 798        call->flags = TRACE_EVENT_FL_TRACEPOINT;
 799        call->class->reg = trace_event_reg;
 800        call->class->probe = trace_event_raw_event_synth;
 801        call->data = event;
 802        call->tp = event->tp;
 803
 804        ret = trace_add_event_call(call);
 805        if (ret) {
 806                pr_warn("Failed to register synthetic event: %s\n",
 807                        trace_event_name(call));
 808                goto err;
 809        }
 810
 811        ret = set_synth_event_print_fmt(call);
 812        if (ret < 0) {
 813                trace_remove_event_call(call);
 814                goto err;
 815        }
 816 out:
 817        return ret;
 818 err:
 819        unregister_trace_event(&call->event);
 820        goto out;
 821}
 822
 823static int unregister_synth_event(struct synth_event *event)
 824{
 825        struct trace_event_call *call = &event->call;
 826        int ret;
 827
 828        ret = trace_remove_event_call(call);
 829
 830        return ret;
 831}
 832
 833static void free_synth_event(struct synth_event *event)
 834{
 835        unsigned int i;
 836
 837        if (!event)
 838                return;
 839
 840        for (i = 0; i < event->n_fields; i++)
 841                free_synth_field(event->fields[i]);
 842
 843        kfree(event->fields);
 844        kfree(event->dynamic_fields);
 845        kfree(event->name);
 846        kfree(event->class.system);
 847        free_synth_tracepoint(event->tp);
 848        free_synth_event_print_fmt(&event->call);
 849        kfree(event);
 850}
 851
 852static struct synth_event *alloc_synth_event(const char *name, int n_fields,
 853                                             struct synth_field **fields)
 854{
 855        unsigned int i, j, n_dynamic_fields = 0;
 856        struct synth_event *event;
 857
 858        event = kzalloc(sizeof(*event), GFP_KERNEL);
 859        if (!event) {
 860                event = ERR_PTR(-ENOMEM);
 861                goto out;
 862        }
 863
 864        event->name = kstrdup(name, GFP_KERNEL);
 865        if (!event->name) {
 866                kfree(event);
 867                event = ERR_PTR(-ENOMEM);
 868                goto out;
 869        }
 870
 871        event->fields = kcalloc(n_fields, sizeof(*event->fields), GFP_KERNEL);
 872        if (!event->fields) {
 873                free_synth_event(event);
 874                event = ERR_PTR(-ENOMEM);
 875                goto out;
 876        }
 877
 878        for (i = 0; i < n_fields; i++)
 879                if (fields[i]->is_dynamic)
 880                        n_dynamic_fields++;
 881
 882        if (n_dynamic_fields) {
 883                event->dynamic_fields = kcalloc(n_dynamic_fields,
 884                                                sizeof(*event->dynamic_fields),
 885                                                GFP_KERNEL);
 886                if (!event->dynamic_fields) {
 887                        free_synth_event(event);
 888                        event = ERR_PTR(-ENOMEM);
 889                        goto out;
 890                }
 891        }
 892
 893        dyn_event_init(&event->devent, &synth_event_ops);
 894
 895        for (i = 0, j = 0; i < n_fields; i++) {
 896                fields[i]->field_pos = i;
 897                event->fields[i] = fields[i];
 898
 899                if (fields[i]->is_dynamic)
 900                        event->dynamic_fields[j++] = fields[i];
 901        }
 902        event->n_dynamic_fields = j;
 903        event->n_fields = n_fields;
 904 out:
 905        return event;
 906}
 907
 908static int synth_event_check_arg_fn(void *data)
 909{
 910        struct dynevent_arg_pair *arg_pair = data;
 911        int size;
 912
 913        size = synth_field_size((char *)arg_pair->lhs);
 914        if (size == 0) {
 915                if (strstr((char *)arg_pair->lhs, "["))
 916                        return 0;
 917        }
 918
 919        return size ? 0 : -EINVAL;
 920}
 921
 922/**
 923 * synth_event_add_field - Add a new field to a synthetic event cmd
 924 * @cmd: A pointer to the dynevent_cmd struct representing the new event
 925 * @type: The type of the new field to add
 926 * @name: The name of the new field to add
 927 *
 928 * Add a new field to a synthetic event cmd object.  Field ordering is in
 929 * the same order the fields are added.
 930 *
 931 * See synth_field_size() for available types. If field_name contains
 932 * [n] the field is considered to be an array.
 933 *
 934 * Return: 0 if successful, error otherwise.
 935 */
 936int synth_event_add_field(struct dynevent_cmd *cmd, const char *type,
 937                          const char *name)
 938{
 939        struct dynevent_arg_pair arg_pair;
 940        int ret;
 941
 942        if (cmd->type != DYNEVENT_TYPE_SYNTH)
 943                return -EINVAL;
 944
 945        if (!type || !name)
 946                return -EINVAL;
 947
 948        dynevent_arg_pair_init(&arg_pair, 0, ';');
 949
 950        arg_pair.lhs = type;
 951        arg_pair.rhs = name;
 952
 953        ret = dynevent_arg_pair_add(cmd, &arg_pair, synth_event_check_arg_fn);
 954        if (ret)
 955                return ret;
 956
 957        if (++cmd->n_fields > SYNTH_FIELDS_MAX)
 958                ret = -EINVAL;
 959
 960        return ret;
 961}
 962EXPORT_SYMBOL_GPL(synth_event_add_field);
 963
 964/**
 965 * synth_event_add_field_str - Add a new field to a synthetic event cmd
 966 * @cmd: A pointer to the dynevent_cmd struct representing the new event
 967 * @type_name: The type and name of the new field to add, as a single string
 968 *
 969 * Add a new field to a synthetic event cmd object, as a single
 970 * string.  The @type_name string is expected to be of the form 'type
 971 * name', which will be appended by ';'.  No sanity checking is done -
 972 * what's passed in is assumed to already be well-formed.  Field
 973 * ordering is in the same order the fields are added.
 974 *
 975 * See synth_field_size() for available types. If field_name contains
 976 * [n] the field is considered to be an array.
 977 *
 978 * Return: 0 if successful, error otherwise.
 979 */
 980int synth_event_add_field_str(struct dynevent_cmd *cmd, const char *type_name)
 981{
 982        struct dynevent_arg arg;
 983        int ret;
 984
 985        if (cmd->type != DYNEVENT_TYPE_SYNTH)
 986                return -EINVAL;
 987
 988        if (!type_name)
 989                return -EINVAL;
 990
 991        dynevent_arg_init(&arg, ';');
 992
 993        arg.str = type_name;
 994
 995        ret = dynevent_arg_add(cmd, &arg, NULL);
 996        if (ret)
 997                return ret;
 998
 999        if (++cmd->n_fields > SYNTH_FIELDS_MAX)
1000                ret = -EINVAL;
1001
1002        return ret;
1003}
1004EXPORT_SYMBOL_GPL(synth_event_add_field_str);
1005
1006/**
1007 * synth_event_add_fields - Add multiple fields to a synthetic event cmd
1008 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1009 * @fields: An array of type/name field descriptions
1010 * @n_fields: The number of field descriptions contained in the fields array
1011 *
1012 * Add a new set of fields to a synthetic event cmd object.  The event
1013 * fields that will be defined for the event should be passed in as an
1014 * array of struct synth_field_desc, and the number of elements in the
1015 * array passed in as n_fields.  Field ordering will retain the
1016 * ordering given in the fields array.
1017 *
1018 * See synth_field_size() for available types. If field_name contains
1019 * [n] the field is considered to be an array.
1020 *
1021 * Return: 0 if successful, error otherwise.
1022 */
1023int synth_event_add_fields(struct dynevent_cmd *cmd,
1024                           struct synth_field_desc *fields,
1025                           unsigned int n_fields)
1026{
1027        unsigned int i;
1028        int ret = 0;
1029
1030        for (i = 0; i < n_fields; i++) {
1031                if (fields[i].type == NULL || fields[i].name == NULL) {
1032                        ret = -EINVAL;
1033                        break;
1034                }
1035
1036                ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1037                if (ret)
1038                        break;
1039        }
1040
1041        return ret;
1042}
1043EXPORT_SYMBOL_GPL(synth_event_add_fields);
1044
1045/**
1046 * __synth_event_gen_cmd_start - Start a synthetic event command from arg list
1047 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1048 * @name: The name of the synthetic event
1049 * @mod: The module creating the event, NULL if not created from a module
1050 * @args: Variable number of arg (pairs), one pair for each field
1051 *
1052 * NOTE: Users normally won't want to call this function directly, but
1053 * rather use the synth_event_gen_cmd_start() wrapper, which
1054 * automatically adds a NULL to the end of the arg list.  If this
1055 * function is used directly, make sure the last arg in the variable
1056 * arg list is NULL.
1057 *
1058 * Generate a synthetic event command to be executed by
1059 * synth_event_gen_cmd_end().  This function can be used to generate
1060 * the complete command or only the first part of it; in the latter
1061 * case, synth_event_add_field(), synth_event_add_field_str(), or
1062 * synth_event_add_fields() can be used to add more fields following
1063 * this.
1064 *
1065 * There should be an even number variable args, each pair consisting
1066 * of a type followed by a field name.
1067 *
1068 * See synth_field_size() for available types. If field_name contains
1069 * [n] the field is considered to be an array.
1070 *
1071 * Return: 0 if successful, error otherwise.
1072 */
1073int __synth_event_gen_cmd_start(struct dynevent_cmd *cmd, const char *name,
1074                                struct module *mod, ...)
1075{
1076        struct dynevent_arg arg;
1077        va_list args;
1078        int ret;
1079
1080        cmd->event_name = name;
1081        cmd->private_data = mod;
1082
1083        if (cmd->type != DYNEVENT_TYPE_SYNTH)
1084                return -EINVAL;
1085
1086        dynevent_arg_init(&arg, 0);
1087        arg.str = name;
1088        ret = dynevent_arg_add(cmd, &arg, NULL);
1089        if (ret)
1090                return ret;
1091
1092        va_start(args, mod);
1093        for (;;) {
1094                const char *type, *name;
1095
1096                type = va_arg(args, const char *);
1097                if (!type)
1098                        break;
1099                name = va_arg(args, const char *);
1100                if (!name)
1101                        break;
1102
1103                if (++cmd->n_fields > SYNTH_FIELDS_MAX) {
1104                        ret = -EINVAL;
1105                        break;
1106                }
1107
1108                ret = synth_event_add_field(cmd, type, name);
1109                if (ret)
1110                        break;
1111        }
1112        va_end(args);
1113
1114        return ret;
1115}
1116EXPORT_SYMBOL_GPL(__synth_event_gen_cmd_start);
1117
1118/**
1119 * synth_event_gen_cmd_array_start - Start synthetic event command from an array
1120 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1121 * @name: The name of the synthetic event
1122 * @fields: An array of type/name field descriptions
1123 * @n_fields: The number of field descriptions contained in the fields array
1124 *
1125 * Generate a synthetic event command to be executed by
1126 * synth_event_gen_cmd_end().  This function can be used to generate
1127 * the complete command or only the first part of it; in the latter
1128 * case, synth_event_add_field(), synth_event_add_field_str(), or
1129 * synth_event_add_fields() can be used to add more fields following
1130 * this.
1131 *
1132 * The event fields that will be defined for the event should be
1133 * passed in as an array of struct synth_field_desc, and the number of
1134 * elements in the array passed in as n_fields.  Field ordering will
1135 * retain the ordering given in the fields array.
1136 *
1137 * See synth_field_size() for available types. If field_name contains
1138 * [n] the field is considered to be an array.
1139 *
1140 * Return: 0 if successful, error otherwise.
1141 */
1142int synth_event_gen_cmd_array_start(struct dynevent_cmd *cmd, const char *name,
1143                                    struct module *mod,
1144                                    struct synth_field_desc *fields,
1145                                    unsigned int n_fields)
1146{
1147        struct dynevent_arg arg;
1148        unsigned int i;
1149        int ret = 0;
1150
1151        cmd->event_name = name;
1152        cmd->private_data = mod;
1153
1154        if (cmd->type != DYNEVENT_TYPE_SYNTH)
1155                return -EINVAL;
1156
1157        if (n_fields > SYNTH_FIELDS_MAX)
1158                return -EINVAL;
1159
1160        dynevent_arg_init(&arg, 0);
1161        arg.str = name;
1162        ret = dynevent_arg_add(cmd, &arg, NULL);
1163        if (ret)
1164                return ret;
1165
1166        for (i = 0; i < n_fields; i++) {
1167                if (fields[i].type == NULL || fields[i].name == NULL)
1168                        return -EINVAL;
1169
1170                ret = synth_event_add_field(cmd, fields[i].type, fields[i].name);
1171                if (ret)
1172                        break;
1173        }
1174
1175        return ret;
1176}
1177EXPORT_SYMBOL_GPL(synth_event_gen_cmd_array_start);
1178
1179static int __create_synth_event(const char *name, const char *raw_fields)
1180{
1181        char **argv, *field_str, *tmp_fields, *saved_fields = NULL;
1182        struct synth_field *field, *fields[SYNTH_FIELDS_MAX];
1183        int consumed, cmd_version = 1, n_fields_this_loop;
1184        int i, argc, n_fields = 0, ret = 0;
1185        struct synth_event *event = NULL;
1186
1187        /*
1188         * Argument syntax:
1189         *  - Add synthetic event: <event_name> field[;field] ...
1190         *  - Remove synthetic event: !<event_name> field[;field] ...
1191         *      where 'field' = type field_name
1192         */
1193
1194        if (name[0] == '\0') {
1195                synth_err(SYNTH_ERR_INVALID_CMD, 0);
1196                return -EINVAL;
1197        }
1198
1199        if (!is_good_name(name)) {
1200                synth_err(SYNTH_ERR_BAD_NAME, errpos(name));
1201                return -EINVAL;
1202        }
1203
1204        mutex_lock(&event_mutex);
1205
1206        event = find_synth_event(name);
1207        if (event) {
1208                synth_err(SYNTH_ERR_EVENT_EXISTS, errpos(name));
1209                ret = -EEXIST;
1210                goto err;
1211        }
1212
1213        tmp_fields = saved_fields = kstrdup(raw_fields, GFP_KERNEL);
1214        if (!tmp_fields) {
1215                ret = -ENOMEM;
1216                goto err;
1217        }
1218
1219        while ((field_str = strsep(&tmp_fields, ";")) != NULL) {
1220                argv = argv_split(GFP_KERNEL, field_str, &argc);
1221                if (!argv) {
1222                        ret = -ENOMEM;
1223                        goto err;
1224                }
1225
1226                if (!argc) {
1227                        argv_free(argv);
1228                        continue;
1229                }
1230
1231                n_fields_this_loop = 0;
1232                consumed = 0;
1233                while (argc > consumed) {
1234                        int field_version;
1235
1236                        field = parse_synth_field(argc - consumed,
1237                                                  argv + consumed, &consumed,
1238                                                  &field_version);
1239                        if (IS_ERR(field)) {
1240                                argv_free(argv);
1241                                ret = PTR_ERR(field);
1242                                goto err;
1243                        }
1244
1245                        /*
1246                         * Track the highest version of any field we
1247                         * found in the command.
1248                         */
1249                        if (field_version > cmd_version)
1250                                cmd_version = field_version;
1251
1252                        /*
1253                         * Now sort out what is and isn't valid for
1254                         * each supported version.
1255                         *
1256                         * If we see more than 1 field per loop, it
1257                         * means we have multiple fields between
1258                         * semicolons, and that's something we no
1259                         * longer support in a version 2 or greater
1260                         * command.
1261                         */
1262                        if (cmd_version > 1 && n_fields_this_loop >= 1) {
1263                                synth_err(SYNTH_ERR_INVALID_CMD, errpos(field_str));
1264                                ret = -EINVAL;
1265                                goto err;
1266                        }
1267
1268                        fields[n_fields++] = field;
1269                        if (n_fields == SYNTH_FIELDS_MAX) {
1270                                synth_err(SYNTH_ERR_TOO_MANY_FIELDS, 0);
1271                                ret = -EINVAL;
1272                                goto err;
1273                        }
1274
1275                        n_fields_this_loop++;
1276                }
1277
1278                if (consumed < argc) {
1279                        synth_err(SYNTH_ERR_INVALID_CMD, 0);
1280                        ret = -EINVAL;
1281                        goto err;
1282                }
1283
1284                argv_free(argv);
1285        }
1286
1287        if (n_fields == 0) {
1288                synth_err(SYNTH_ERR_INVALID_CMD, 0);
1289                ret = -EINVAL;
1290                goto err;
1291        }
1292
1293        event = alloc_synth_event(name, n_fields, fields);
1294        if (IS_ERR(event)) {
1295                ret = PTR_ERR(event);
1296                event = NULL;
1297                goto err;
1298        }
1299        ret = register_synth_event(event);
1300        if (!ret)
1301                dyn_event_add(&event->devent);
1302        else
1303                free_synth_event(event);
1304 out:
1305        mutex_unlock(&event_mutex);
1306
1307        kfree(saved_fields);
1308
1309        return ret;
1310 err:
1311        for (i = 0; i < n_fields; i++)
1312                free_synth_field(fields[i]);
1313
1314        goto out;
1315}
1316
1317/**
1318 * synth_event_create - Create a new synthetic event
1319 * @name: The name of the new synthetic event
1320 * @fields: An array of type/name field descriptions
1321 * @n_fields: The number of field descriptions contained in the fields array
1322 * @mod: The module creating the event, NULL if not created from a module
1323 *
1324 * Create a new synthetic event with the given name under the
1325 * trace/events/synthetic/ directory.  The event fields that will be
1326 * defined for the event should be passed in as an array of struct
1327 * synth_field_desc, and the number elements in the array passed in as
1328 * n_fields. Field ordering will retain the ordering given in the
1329 * fields array.
1330 *
1331 * If the new synthetic event is being created from a module, the mod
1332 * param must be non-NULL.  This will ensure that the trace buffer
1333 * won't contain unreadable events.
1334 *
1335 * The new synth event should be deleted using synth_event_delete()
1336 * function.  The new synthetic event can be generated from modules or
1337 * other kernel code using trace_synth_event() and related functions.
1338 *
1339 * Return: 0 if successful, error otherwise.
1340 */
1341int synth_event_create(const char *name, struct synth_field_desc *fields,
1342                       unsigned int n_fields, struct module *mod)
1343{
1344        struct dynevent_cmd cmd;
1345        char *buf;
1346        int ret;
1347
1348        buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
1349        if (!buf)
1350                return -ENOMEM;
1351
1352        synth_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
1353
1354        ret = synth_event_gen_cmd_array_start(&cmd, name, mod,
1355                                              fields, n_fields);
1356        if (ret)
1357                goto out;
1358
1359        ret = synth_event_gen_cmd_end(&cmd);
1360 out:
1361        kfree(buf);
1362
1363        return ret;
1364}
1365EXPORT_SYMBOL_GPL(synth_event_create);
1366
1367static int destroy_synth_event(struct synth_event *se)
1368{
1369        int ret;
1370
1371        if (se->ref)
1372                ret = -EBUSY;
1373        else {
1374                ret = unregister_synth_event(se);
1375                if (!ret) {
1376                        dyn_event_remove(&se->devent);
1377                        free_synth_event(se);
1378                }
1379        }
1380
1381        return ret;
1382}
1383
1384/**
1385 * synth_event_delete - Delete a synthetic event
1386 * @event_name: The name of the new synthetic event
1387 *
1388 * Delete a synthetic event that was created with synth_event_create().
1389 *
1390 * Return: 0 if successful, error otherwise.
1391 */
1392int synth_event_delete(const char *event_name)
1393{
1394        struct synth_event *se = NULL;
1395        struct module *mod = NULL;
1396        int ret = -ENOENT;
1397
1398        mutex_lock(&event_mutex);
1399        se = find_synth_event(event_name);
1400        if (se) {
1401                mod = se->mod;
1402                ret = destroy_synth_event(se);
1403        }
1404        mutex_unlock(&event_mutex);
1405
1406        if (mod) {
1407                mutex_lock(&trace_types_lock);
1408                /*
1409                 * It is safest to reset the ring buffer if the module
1410                 * being unloaded registered any events that were
1411                 * used. The only worry is if a new module gets
1412                 * loaded, and takes on the same id as the events of
1413                 * this module. When printing out the buffer, traced
1414                 * events left over from this module may be passed to
1415                 * the new module events and unexpected results may
1416                 * occur.
1417                 */
1418                tracing_reset_all_online_cpus();
1419                mutex_unlock(&trace_types_lock);
1420        }
1421
1422        return ret;
1423}
1424EXPORT_SYMBOL_GPL(synth_event_delete);
1425
1426static int check_command(const char *raw_command)
1427{
1428        char **argv = NULL, *cmd, *saved_cmd, *name_and_field;
1429        int argc, ret = 0;
1430
1431        cmd = saved_cmd = kstrdup(raw_command, GFP_KERNEL);
1432        if (!cmd)
1433                return -ENOMEM;
1434
1435        name_and_field = strsep(&cmd, ";");
1436        if (!name_and_field) {
1437                ret = -EINVAL;
1438                goto free;
1439        }
1440
1441        if (name_and_field[0] == '!')
1442                goto free;
1443
1444        argv = argv_split(GFP_KERNEL, name_and_field, &argc);
1445        if (!argv) {
1446                ret = -ENOMEM;
1447                goto free;
1448        }
1449        argv_free(argv);
1450
1451        if (argc < 3)
1452                ret = -EINVAL;
1453free:
1454        kfree(saved_cmd);
1455
1456        return ret;
1457}
1458
1459static int create_or_delete_synth_event(const char *raw_command)
1460{
1461        char *name = NULL, *fields, *p;
1462        int ret = 0;
1463
1464        raw_command = skip_spaces(raw_command);
1465        if (raw_command[0] == '\0')
1466                return ret;
1467
1468        last_cmd_set(raw_command);
1469
1470        ret = check_command(raw_command);
1471        if (ret) {
1472                synth_err(SYNTH_ERR_INVALID_CMD, 0);
1473                return ret;
1474        }
1475
1476        p = strpbrk(raw_command, " \t");
1477        if (!p && raw_command[0] != '!') {
1478                synth_err(SYNTH_ERR_INVALID_CMD, 0);
1479                ret = -EINVAL;
1480                goto free;
1481        }
1482
1483        name = kmemdup_nul(raw_command, p ? p - raw_command : strlen(raw_command), GFP_KERNEL);
1484        if (!name)
1485                return -ENOMEM;
1486
1487        if (name[0] == '!') {
1488                ret = synth_event_delete(name + 1);
1489                goto free;
1490        }
1491
1492        fields = skip_spaces(p);
1493
1494        ret = __create_synth_event(name, fields);
1495free:
1496        kfree(name);
1497
1498        return ret;
1499}
1500
1501static int synth_event_run_command(struct dynevent_cmd *cmd)
1502{
1503        struct synth_event *se;
1504        int ret;
1505
1506        ret = create_or_delete_synth_event(cmd->seq.buffer);
1507        if (ret)
1508                return ret;
1509
1510        se = find_synth_event(cmd->event_name);
1511        if (WARN_ON(!se))
1512                return -ENOENT;
1513
1514        se->mod = cmd->private_data;
1515
1516        return ret;
1517}
1518
1519/**
1520 * synth_event_cmd_init - Initialize a synthetic event command object
1521 * @cmd: A pointer to the dynevent_cmd struct representing the new event
1522 * @buf: A pointer to the buffer used to build the command
1523 * @maxlen: The length of the buffer passed in @buf
1524 *
1525 * Initialize a synthetic event command object.  Use this before
1526 * calling any of the other dyenvent_cmd functions.
1527 */
1528void synth_event_cmd_init(struct dynevent_cmd *cmd, char *buf, int maxlen)
1529{
1530        dynevent_cmd_init(cmd, buf, maxlen, DYNEVENT_TYPE_SYNTH,
1531                          synth_event_run_command);
1532}
1533EXPORT_SYMBOL_GPL(synth_event_cmd_init);
1534
1535static inline int
1536__synth_event_trace_init(struct trace_event_file *file,
1537                         struct synth_event_trace_state *trace_state)
1538{
1539        int ret = 0;
1540
1541        memset(trace_state, '\0', sizeof(*trace_state));
1542
1543        /*
1544         * Normal event tracing doesn't get called at all unless the
1545         * ENABLED bit is set (which attaches the probe thus allowing
1546         * this code to be called, etc).  Because this is called
1547         * directly by the user, we don't have that but we still need
1548         * to honor not logging when disabled.  For the iterated
1549         * trace case, we save the enabled state upon start and just
1550         * ignore the following data calls.
1551         */
1552        if (!(file->flags & EVENT_FILE_FL_ENABLED) ||
1553            trace_trigger_soft_disabled(file)) {
1554                trace_state->disabled = true;
1555                ret = -ENOENT;
1556                goto out;
1557        }
1558
1559        trace_state->event = file->event_call->data;
1560out:
1561        return ret;
1562}
1563
1564static inline int
1565__synth_event_trace_start(struct trace_event_file *file,
1566                          struct synth_event_trace_state *trace_state,
1567                          int dynamic_fields_size)
1568{
1569        int entry_size, fields_size = 0;
1570        int ret = 0;
1571
1572        fields_size = trace_state->event->n_u64 * sizeof(u64);
1573        fields_size += dynamic_fields_size;
1574
1575        /*
1576         * Avoid ring buffer recursion detection, as this event
1577         * is being performed within another event.
1578         */
1579        trace_state->buffer = file->tr->array_buffer.buffer;
1580        ring_buffer_nest_start(trace_state->buffer);
1581
1582        entry_size = sizeof(*trace_state->entry) + fields_size;
1583        trace_state->entry = trace_event_buffer_reserve(&trace_state->fbuffer,
1584                                                        file,
1585                                                        entry_size);
1586        if (!trace_state->entry) {
1587                ring_buffer_nest_end(trace_state->buffer);
1588                ret = -EINVAL;
1589        }
1590
1591        return ret;
1592}
1593
1594static inline void
1595__synth_event_trace_end(struct synth_event_trace_state *trace_state)
1596{
1597        trace_event_buffer_commit(&trace_state->fbuffer);
1598
1599        ring_buffer_nest_end(trace_state->buffer);
1600}
1601
1602/**
1603 * synth_event_trace - Trace a synthetic event
1604 * @file: The trace_event_file representing the synthetic event
1605 * @n_vals: The number of values in vals
1606 * @args: Variable number of args containing the event values
1607 *
1608 * Trace a synthetic event using the values passed in the variable
1609 * argument list.
1610 *
1611 * The argument list should be a list 'n_vals' u64 values.  The number
1612 * of vals must match the number of field in the synthetic event, and
1613 * must be in the same order as the synthetic event fields.
1614 *
1615 * All vals should be cast to u64, and string vals are just pointers
1616 * to strings, cast to u64.  Strings will be copied into space
1617 * reserved in the event for the string, using these pointers.
1618 *
1619 * Return: 0 on success, err otherwise.
1620 */
1621int synth_event_trace(struct trace_event_file *file, unsigned int n_vals, ...)
1622{
1623        unsigned int i, n_u64, len, data_size = 0;
1624        struct synth_event_trace_state state;
1625        va_list args;
1626        int ret;
1627
1628        ret = __synth_event_trace_init(file, &state);
1629        if (ret) {
1630                if (ret == -ENOENT)
1631                        ret = 0; /* just disabled, not really an error */
1632                return ret;
1633        }
1634
1635        if (state.event->n_dynamic_fields) {
1636                va_start(args, n_vals);
1637
1638                for (i = 0; i < state.event->n_fields; i++) {
1639                        u64 val = va_arg(args, u64);
1640
1641                        if (state.event->fields[i]->is_string &&
1642                            state.event->fields[i]->is_dynamic) {
1643                                char *str_val = (char *)(long)val;
1644
1645                                data_size += strlen(str_val) + 1;
1646                        }
1647                }
1648
1649                va_end(args);
1650        }
1651
1652        ret = __synth_event_trace_start(file, &state, data_size);
1653        if (ret)
1654                return ret;
1655
1656        if (n_vals != state.event->n_fields) {
1657                ret = -EINVAL;
1658                goto out;
1659        }
1660
1661        data_size = 0;
1662
1663        va_start(args, n_vals);
1664        for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1665                u64 val;
1666
1667                val = va_arg(args, u64);
1668
1669                if (state.event->fields[i]->is_string) {
1670                        char *str_val = (char *)(long)val;
1671
1672                        len = trace_string(state.entry, state.event, str_val,
1673                                           state.event->fields[i]->is_dynamic,
1674                                           data_size, &n_u64);
1675                        data_size += len; /* only dynamic string increments */
1676                } else {
1677                        struct synth_field *field = state.event->fields[i];
1678
1679                        switch (field->size) {
1680                        case 1:
1681                                *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1682                                break;
1683
1684                        case 2:
1685                                *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1686                                break;
1687
1688                        case 4:
1689                                *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1690                                break;
1691
1692                        default:
1693                                state.entry->fields[n_u64] = val;
1694                                break;
1695                        }
1696                        n_u64++;
1697                }
1698        }
1699        va_end(args);
1700out:
1701        __synth_event_trace_end(&state);
1702
1703        return ret;
1704}
1705EXPORT_SYMBOL_GPL(synth_event_trace);
1706
1707/**
1708 * synth_event_trace_array - Trace a synthetic event from an array
1709 * @file: The trace_event_file representing the synthetic event
1710 * @vals: Array of values
1711 * @n_vals: The number of values in vals
1712 *
1713 * Trace a synthetic event using the values passed in as 'vals'.
1714 *
1715 * The 'vals' array is just an array of 'n_vals' u64.  The number of
1716 * vals must match the number of field in the synthetic event, and
1717 * must be in the same order as the synthetic event fields.
1718 *
1719 * All vals should be cast to u64, and string vals are just pointers
1720 * to strings, cast to u64.  Strings will be copied into space
1721 * reserved in the event for the string, using these pointers.
1722 *
1723 * Return: 0 on success, err otherwise.
1724 */
1725int synth_event_trace_array(struct trace_event_file *file, u64 *vals,
1726                            unsigned int n_vals)
1727{
1728        unsigned int i, n_u64, field_pos, len, data_size = 0;
1729        struct synth_event_trace_state state;
1730        char *str_val;
1731        int ret;
1732
1733        ret = __synth_event_trace_init(file, &state);
1734        if (ret) {
1735                if (ret == -ENOENT)
1736                        ret = 0; /* just disabled, not really an error */
1737                return ret;
1738        }
1739
1740        if (state.event->n_dynamic_fields) {
1741                for (i = 0; i < state.event->n_dynamic_fields; i++) {
1742                        field_pos = state.event->dynamic_fields[i]->field_pos;
1743                        str_val = (char *)(long)vals[field_pos];
1744                        len = strlen(str_val) + 1;
1745                        data_size += len;
1746                }
1747        }
1748
1749        ret = __synth_event_trace_start(file, &state, data_size);
1750        if (ret)
1751                return ret;
1752
1753        if (n_vals != state.event->n_fields) {
1754                ret = -EINVAL;
1755                goto out;
1756        }
1757
1758        data_size = 0;
1759
1760        for (i = 0, n_u64 = 0; i < state.event->n_fields; i++) {
1761                if (state.event->fields[i]->is_string) {
1762                        char *str_val = (char *)(long)vals[i];
1763
1764                        len = trace_string(state.entry, state.event, str_val,
1765                                           state.event->fields[i]->is_dynamic,
1766                                           data_size, &n_u64);
1767                        data_size += len; /* only dynamic string increments */
1768                } else {
1769                        struct synth_field *field = state.event->fields[i];
1770                        u64 val = vals[i];
1771
1772                        switch (field->size) {
1773                        case 1:
1774                                *(u8 *)&state.entry->fields[n_u64] = (u8)val;
1775                                break;
1776
1777                        case 2:
1778                                *(u16 *)&state.entry->fields[n_u64] = (u16)val;
1779                                break;
1780
1781                        case 4:
1782                                *(u32 *)&state.entry->fields[n_u64] = (u32)val;
1783                                break;
1784
1785                        default:
1786                                state.entry->fields[n_u64] = val;
1787                                break;
1788                        }
1789                        n_u64++;
1790                }
1791        }
1792out:
1793        __synth_event_trace_end(&state);
1794
1795        return ret;
1796}
1797EXPORT_SYMBOL_GPL(synth_event_trace_array);
1798
1799/**
1800 * synth_event_trace_start - Start piecewise synthetic event trace
1801 * @file: The trace_event_file representing the synthetic event
1802 * @trace_state: A pointer to object tracking the piecewise trace state
1803 *
1804 * Start the trace of a synthetic event field-by-field rather than all
1805 * at once.
1806 *
1807 * This function 'opens' an event trace, which means space is reserved
1808 * for the event in the trace buffer, after which the event's
1809 * individual field values can be set through either
1810 * synth_event_add_next_val() or synth_event_add_val().
1811 *
1812 * A pointer to a trace_state object is passed in, which will keep
1813 * track of the current event trace state until the event trace is
1814 * closed (and the event finally traced) using
1815 * synth_event_trace_end().
1816 *
1817 * Note that synth_event_trace_end() must be called after all values
1818 * have been added for each event trace, regardless of whether adding
1819 * all field values succeeded or not.
1820 *
1821 * Note also that for a given event trace, all fields must be added
1822 * using either synth_event_add_next_val() or synth_event_add_val()
1823 * but not both together or interleaved.
1824 *
1825 * Return: 0 on success, err otherwise.
1826 */
1827int synth_event_trace_start(struct trace_event_file *file,
1828                            struct synth_event_trace_state *trace_state)
1829{
1830        int ret;
1831
1832        if (!trace_state)
1833                return -EINVAL;
1834
1835        ret = __synth_event_trace_init(file, trace_state);
1836        if (ret) {
1837                if (ret == -ENOENT)
1838                        ret = 0; /* just disabled, not really an error */
1839                return ret;
1840        }
1841
1842        if (trace_state->event->n_dynamic_fields)
1843                return -ENOTSUPP;
1844
1845        ret = __synth_event_trace_start(file, trace_state, 0);
1846
1847        return ret;
1848}
1849EXPORT_SYMBOL_GPL(synth_event_trace_start);
1850
1851static int __synth_event_add_val(const char *field_name, u64 val,
1852                                 struct synth_event_trace_state *trace_state)
1853{
1854        struct synth_field *field = NULL;
1855        struct synth_trace_event *entry;
1856        struct synth_event *event;
1857        int i, ret = 0;
1858
1859        if (!trace_state) {
1860                ret = -EINVAL;
1861                goto out;
1862        }
1863
1864        /* can't mix add_next_synth_val() with add_synth_val() */
1865        if (field_name) {
1866                if (trace_state->add_next) {
1867                        ret = -EINVAL;
1868                        goto out;
1869                }
1870                trace_state->add_name = true;
1871        } else {
1872                if (trace_state->add_name) {
1873                        ret = -EINVAL;
1874                        goto out;
1875                }
1876                trace_state->add_next = true;
1877        }
1878
1879        if (trace_state->disabled)
1880                goto out;
1881
1882        event = trace_state->event;
1883        if (trace_state->add_name) {
1884                for (i = 0; i < event->n_fields; i++) {
1885                        field = event->fields[i];
1886                        if (strcmp(field->name, field_name) == 0)
1887                                break;
1888                }
1889                if (!field) {
1890                        ret = -EINVAL;
1891                        goto out;
1892                }
1893        } else {
1894                if (trace_state->cur_field >= event->n_fields) {
1895                        ret = -EINVAL;
1896                        goto out;
1897                }
1898                field = event->fields[trace_state->cur_field++];
1899        }
1900
1901        entry = trace_state->entry;
1902        if (field->is_string) {
1903                char *str_val = (char *)(long)val;
1904                char *str_field;
1905
1906                if (field->is_dynamic) { /* add_val can't do dynamic strings */
1907                        ret = -EINVAL;
1908                        goto out;
1909                }
1910
1911                if (!str_val) {
1912                        ret = -EINVAL;
1913                        goto out;
1914                }
1915
1916                str_field = (char *)&entry->fields[field->offset];
1917                strscpy(str_field, str_val, STR_VAR_LEN_MAX);
1918        } else {
1919                switch (field->size) {
1920                case 1:
1921                        *(u8 *)&trace_state->entry->fields[field->offset] = (u8)val;
1922                        break;
1923
1924                case 2:
1925                        *(u16 *)&trace_state->entry->fields[field->offset] = (u16)val;
1926                        break;
1927
1928                case 4:
1929                        *(u32 *)&trace_state->entry->fields[field->offset] = (u32)val;
1930                        break;
1931
1932                default:
1933                        trace_state->entry->fields[field->offset] = val;
1934                        break;
1935                }
1936        }
1937 out:
1938        return ret;
1939}
1940
1941/**
1942 * synth_event_add_next_val - Add the next field's value to an open synth trace
1943 * @val: The value to set the next field to
1944 * @trace_state: A pointer to object tracking the piecewise trace state
1945 *
1946 * Set the value of the next field in an event that's been opened by
1947 * synth_event_trace_start().
1948 *
1949 * The val param should be the value cast to u64.  If the value points
1950 * to a string, the val param should be a char * cast to u64.
1951 *
1952 * This function assumes all the fields in an event are to be set one
1953 * after another - successive calls to this function are made, one for
1954 * each field, in the order of the fields in the event, until all
1955 * fields have been set.  If you'd rather set each field individually
1956 * without regard to ordering, synth_event_add_val() can be used
1957 * instead.
1958 *
1959 * Note however that synth_event_add_next_val() and
1960 * synth_event_add_val() can't be intermixed for a given event trace -
1961 * one or the other but not both can be used at the same time.
1962 *
1963 * Note also that synth_event_trace_end() must be called after all
1964 * values have been added for each event trace, regardless of whether
1965 * adding all field values succeeded or not.
1966 *
1967 * Return: 0 on success, err otherwise.
1968 */
1969int synth_event_add_next_val(u64 val,
1970                             struct synth_event_trace_state *trace_state)
1971{
1972        return __synth_event_add_val(NULL, val, trace_state);
1973}
1974EXPORT_SYMBOL_GPL(synth_event_add_next_val);
1975
1976/**
1977 * synth_event_add_val - Add a named field's value to an open synth trace
1978 * @field_name: The name of the synthetic event field value to set
1979 * @val: The value to set the next field to
1980 * @trace_state: A pointer to object tracking the piecewise trace state
1981 *
1982 * Set the value of the named field in an event that's been opened by
1983 * synth_event_trace_start().
1984 *
1985 * The val param should be the value cast to u64.  If the value points
1986 * to a string, the val param should be a char * cast to u64.
1987 *
1988 * This function looks up the field name, and if found, sets the field
1989 * to the specified value.  This lookup makes this function more
1990 * expensive than synth_event_add_next_val(), so use that or the
1991 * none-piecewise synth_event_trace() instead if efficiency is more
1992 * important.
1993 *
1994 * Note however that synth_event_add_next_val() and
1995 * synth_event_add_val() can't be intermixed for a given event trace -
1996 * one or the other but not both can be used at the same time.
1997 *
1998 * Note also that synth_event_trace_end() must be called after all
1999 * values have been added for each event trace, regardless of whether
2000 * adding all field values succeeded or not.
2001 *
2002 * Return: 0 on success, err otherwise.
2003 */
2004int synth_event_add_val(const char *field_name, u64 val,
2005                        struct synth_event_trace_state *trace_state)
2006{
2007        return __synth_event_add_val(field_name, val, trace_state);
2008}
2009EXPORT_SYMBOL_GPL(synth_event_add_val);
2010
2011/**
2012 * synth_event_trace_end - End piecewise synthetic event trace
2013 * @trace_state: A pointer to object tracking the piecewise trace state
2014 *
2015 * End the trace of a synthetic event opened by
2016 * synth_event_trace__start().
2017 *
2018 * This function 'closes' an event trace, which basically means that
2019 * it commits the reserved event and cleans up other loose ends.
2020 *
2021 * A pointer to a trace_state object is passed in, which will keep
2022 * track of the current event trace state opened with
2023 * synth_event_trace_start().
2024 *
2025 * Note that this function must be called after all values have been
2026 * added for each event trace, regardless of whether adding all field
2027 * values succeeded or not.
2028 *
2029 * Return: 0 on success, err otherwise.
2030 */
2031int synth_event_trace_end(struct synth_event_trace_state *trace_state)
2032{
2033        if (!trace_state)
2034                return -EINVAL;
2035
2036        __synth_event_trace_end(trace_state);
2037
2038        return 0;
2039}
2040EXPORT_SYMBOL_GPL(synth_event_trace_end);
2041
2042static int create_synth_event(const char *raw_command)
2043{
2044        char *fields, *p;
2045        const char *name;
2046        int len, ret = 0;
2047
2048        raw_command = skip_spaces(raw_command);
2049        if (raw_command[0] == '\0')
2050                return ret;
2051
2052        last_cmd_set(raw_command);
2053
2054        p = strpbrk(raw_command, " \t");
2055        if (!p) {
2056                synth_err(SYNTH_ERR_INVALID_CMD, 0);
2057                return -EINVAL;
2058        }
2059
2060        fields = skip_spaces(p);
2061
2062        name = raw_command;
2063
2064        if (name[0] != 's' || name[1] != ':')
2065                return -ECANCELED;
2066        name += 2;
2067
2068        /* This interface accepts group name prefix */
2069        if (strchr(name, '/')) {
2070                len = str_has_prefix(name, SYNTH_SYSTEM "/");
2071                if (len == 0) {
2072                        synth_err(SYNTH_ERR_INVALID_DYN_CMD, 0);
2073                        return -EINVAL;
2074                }
2075                name += len;
2076        }
2077
2078        len = name - raw_command;
2079
2080        ret = check_command(raw_command + len);
2081        if (ret) {
2082                synth_err(SYNTH_ERR_INVALID_CMD, 0);
2083                return ret;
2084        }
2085
2086        name = kmemdup_nul(raw_command + len, p - raw_command - len, GFP_KERNEL);
2087        if (!name)
2088                return -ENOMEM;
2089
2090        ret = __create_synth_event(name, fields);
2091
2092        kfree(name);
2093
2094        return ret;
2095}
2096
2097static int synth_event_release(struct dyn_event *ev)
2098{
2099        struct synth_event *event = to_synth_event(ev);
2100        int ret;
2101
2102        if (event->ref)
2103                return -EBUSY;
2104
2105        ret = unregister_synth_event(event);
2106        if (ret)
2107                return ret;
2108
2109        dyn_event_remove(ev);
2110        free_synth_event(event);
2111        return 0;
2112}
2113
2114static int __synth_event_show(struct seq_file *m, struct synth_event *event)
2115{
2116        struct synth_field *field;
2117        unsigned int i;
2118        char *type, *t;
2119
2120        seq_printf(m, "%s\t", event->name);
2121
2122        for (i = 0; i < event->n_fields; i++) {
2123                field = event->fields[i];
2124
2125                type = field->type;
2126                t = strstr(type, "__data_loc");
2127                if (t) { /* __data_loc belongs in format but not event desc */
2128                        t += sizeof("__data_loc");
2129                        type = t;
2130                }
2131
2132                /* parameter values */
2133                seq_printf(m, "%s %s%s", type, field->name,
2134                           i == event->n_fields - 1 ? "" : "; ");
2135        }
2136
2137        seq_putc(m, '\n');
2138
2139        return 0;
2140}
2141
2142static int synth_event_show(struct seq_file *m, struct dyn_event *ev)
2143{
2144        struct synth_event *event = to_synth_event(ev);
2145
2146        seq_printf(m, "s:%s/", event->class.system);
2147
2148        return __synth_event_show(m, event);
2149}
2150
2151static int synth_events_seq_show(struct seq_file *m, void *v)
2152{
2153        struct dyn_event *ev = v;
2154
2155        if (!is_synth_event(ev))
2156                return 0;
2157
2158        return __synth_event_show(m, to_synth_event(ev));
2159}
2160
2161static const struct seq_operations synth_events_seq_op = {
2162        .start  = dyn_event_seq_start,
2163        .next   = dyn_event_seq_next,
2164        .stop   = dyn_event_seq_stop,
2165        .show   = synth_events_seq_show,
2166};
2167
2168static int synth_events_open(struct inode *inode, struct file *file)
2169{
2170        int ret;
2171
2172        ret = security_locked_down(LOCKDOWN_TRACEFS);
2173        if (ret)
2174                return ret;
2175
2176        if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
2177                ret = dyn_events_release_all(&synth_event_ops);
2178                if (ret < 0)
2179                        return ret;
2180        }
2181
2182        return seq_open(file, &synth_events_seq_op);
2183}
2184
2185static ssize_t synth_events_write(struct file *file,
2186                                  const char __user *buffer,
2187                                  size_t count, loff_t *ppos)
2188{
2189        return trace_parse_run_command(file, buffer, count, ppos,
2190                                       create_or_delete_synth_event);
2191}
2192
2193static const struct file_operations synth_events_fops = {
2194        .open           = synth_events_open,
2195        .write          = synth_events_write,
2196        .read           = seq_read,
2197        .llseek         = seq_lseek,
2198        .release        = seq_release,
2199};
2200
2201/*
2202 * Register dynevent at core_initcall. This allows kernel to setup kprobe
2203 * events in postcore_initcall without tracefs.
2204 */
2205static __init int trace_events_synth_init_early(void)
2206{
2207        int err = 0;
2208
2209        err = dyn_event_register(&synth_event_ops);
2210        if (err)
2211                pr_warn("Could not register synth_event_ops\n");
2212
2213        return err;
2214}
2215core_initcall(trace_events_synth_init_early);
2216
2217static __init int trace_events_synth_init(void)
2218{
2219        struct dentry *entry = NULL;
2220        int err = 0;
2221        err = tracing_init_dentry();
2222        if (err)
2223                goto err;
2224
2225        entry = tracefs_create_file("synthetic_events", 0644, NULL,
2226                                    NULL, &synth_events_fops);
2227        if (!entry) {
2228                err = -ENODEV;
2229                goto err;
2230        }
2231
2232        return err;
2233 err:
2234        pr_warn("Could not create tracefs 'synthetic_events' entry\n");
2235
2236        return err;
2237}
2238
2239fs_initcall(trace_events_synth_init);
2240