tools/perf/util/data-convert-json.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * JSON export.
   4  *
   5  * Copyright (C) 2021, CodeWeavers Inc. <nfraser@codeweavers.com>
   6  */
   7
   8 #include "data-convert.h"
   9
  10 #include <fcntl.h>
  11 #include <inttypes.h>
  12 #include <sys/stat.h>
  13 #include <unistd.h>
  14
  15 #include "linux/compiler.h"
  16 #include "linux/err.h"
  17 #include "util/auxtrace.h"
  18 #include "util/debug.h"
  19 #include "util/dso.h"
  20 #include "util/event.h"
  21 #include "util/evsel.h"
  22 #include "util/evlist.h"
  23 #include "util/header.h"
  24 #include "util/map.h"
  25 #include "util/session.h"
  26 #include "util/symbol.h"
  27 #include "util/thread.h"
  28 #include "util/tool.h"
  29
  30 struct convert_json {
  31         struct perf_tool tool;
  32         FILE *out;
  33         bool first;
  34         u64 events_count;
  35 };
  36
  37 // Outputs a JSON-encoded string surrounded by quotes with characters escaped.
  38 static void output_json_string(FILE *out, const char *s)
  39 {
  40         fputc('"', out);
  41         while (*s) {
  42                 switch (*s) {
  43
  44                 // required escapes with special forms as per RFC 8259
  45                 case '"':  fputs("\\\"", out); break;
  46                 case '\\': fputs("\\\\", out); break;
  47                 case '\b': fputs("\\b", out);  break;
  48                 case '\f': fputs("\\f", out);  break;
  49                 case '\n': fputs("\\n", out);  break;
  50                 case '\r': fputs("\\r", out);  break;
  51                 case '\t': fputs("\\t", out);  break;
  52
  53                 default:
  54                         // all other control characters must be escaped by hex code
  55                         if (*s <= 0x1f)
  56                                 fprintf(out, "\\u%04x", *s);
  57                         else
  58                                 fputc(*s, out);
  59                         break;
  60                 }
  61
  62                 ++s;
  63         }
  64         fputc('"', out);
  65 }
  66
  67 // Outputs an optional comma, newline and indentation to delimit a new value
  68 // from the previous one in a JSON object or array.
  69 static void output_json_delimiters(FILE *out, bool comma, int depth)
  70 {
  71         int i;
  72
  73         if (comma)
  74                 fputc(',', out);
  75         fputc('\n', out);
  76         for (i = 0; i < depth; ++i)
  77                 fputc('\t', out);
  78 }
  79
  80 // Outputs a printf format string (with delimiter) as a JSON value.
  81 __printf(4, 5)
  82 static void output_json_format(FILE *out, bool comma, int depth, const char *format, ...)
  83 {
  84         va_list args;
  85
  86         output_json_delimiters(out, comma, depth);
  87         va_start(args, format);
  88         vfprintf(out,  format, args);
  89         va_end(args);
  90 }
  91
  92 // Outputs a JSON key-value pair where the value is a string.
  93 static void output_json_key_string(FILE *out, bool comma, int depth,
  94                 const char *key, const char *value)
  95 {
  96         output_json_delimiters(out, comma, depth);
  97         output_json_string(out, key);
  98         fputs(": ", out);
  99         output_json_string(out, value);
 100 }
 101
 102 // Outputs a JSON key-value pair where the value is a printf format string.
 103 __printf(5, 6)
 104 static void output_json_key_format(FILE *out, bool comma, int depth,
 105                 const char *key, const char *format, ...)
 106 {
 107         va_list args;
 108
 109         output_json_delimiters(out, comma, depth);
 110         output_json_string(out, key);
 111         fputs(": ", out);
 112         va_start(args, format);
 113         vfprintf(out,  format, args);
 114         va_end(args);
 115 }
 116
 117 static void output_sample_callchain_entry(struct perf_tool *tool,
 118                 u64 ip, struct addr_location *al)
 119 {
 120         struct convert_json *c = container_of(tool, struct convert_json, tool);
 121         FILE *out = c->out;
 122
 123         output_json_format(out, false, 4, "{");
 124         output_json_key_format(out, false, 5, "ip", "\"0x%" PRIx64 "\"", ip);
 125
 126         if (al && al->sym && al->sym->namelen) {
 127                 fputc(',', out);
 128                 output_json_key_string(out, false, 5, "symbol", al->sym->name);
 129
 130                 if (al->map && al->map->dso) {
 131                         const char *dso = al->map->dso->short_name;
 132
 133                         if (dso && strlen(dso) > 0) {
 134                                 fputc(',', out);
 135                                 output_json_key_string(out, false, 5, "dso", dso);
 136                         }
 137                 }
 138         }
 139
 140         output_json_format(out, false, 4, "}");
 141 }
 142
 143 static int process_sample_event(struct perf_tool *tool,
 144                                 union perf_event *event __maybe_unused,
 145                                 struct perf_sample *sample,
 146                                 struct evsel *evsel __maybe_unused,
 147                                 struct machine *machine)
 148 {
 149         struct convert_json *c = container_of(tool, struct convert_json, tool);
 150         FILE *out = c->out;
 151         struct addr_location al, tal;
 152         u8 cpumode = PERF_RECORD_MISC_USER;
 153
 154         if (machine__resolve(machine, &al, sample) < 0) {
 155                 pr_err("Sample resolution failed!\n");
 156                 return -1;
 157         }
 158
 159         ++c->events_count;
 160
 161         if (c->first)
 162                 c->first = false;
 163         else
 164                 fputc(',', out);
 165         output_json_format(out, false, 2, "{");
 166
 167         output_json_key_format(out, false, 3, "timestamp", "%" PRIi64, sample->time);
 168         output_json_key_format(out, true, 3, "pid", "%i", al.thread->pid_);
 169         output_json_key_format(out, true, 3, "tid", "%i", al.thread->tid);
 170
 171         if (al.thread->cpu >= 0)
 172                 output_json_key_format(out, true, 3, "cpu", "%i", al.thread->cpu);
 173
 174         output_json_key_string(out, true, 3, "comm", thread__comm_str(al.thread));
 175
 176         output_json_key_format(out, true, 3, "callchain", "[");
 177         if (sample->callchain) {
 178                 unsigned int i;
 179                 bool ok;
 180                 bool first_callchain = true;
 181
 182                 for (i = 0; i < sample->callchain->nr; ++i) {
 183                         u64 ip = sample->callchain->ips[i];
 184
 185                         if (ip >= PERF_CONTEXT_MAX) {
 186                                 switch (ip) {
 187                                 case PERF_CONTEXT_HV:
 188                                         cpumode = PERF_RECORD_MISC_HYPERVISOR;
 189                                         break;
 190                                 case PERF_CONTEXT_KERNEL:
 191                                         cpumode = PERF_RECORD_MISC_KERNEL;
 192                                         break;
 193                                 case PERF_CONTEXT_USER:
 194                                         cpumode = PERF_RECORD_MISC_USER;
 195                                         break;
 196                                 default:
 197                                         pr_debug("invalid callchain context: %"
 198                                                         PRId64 "\n", (s64) ip);
 199                                         break;
 200                                 }
 201                                 continue;
 202                         }
 203
 204                         if (first_callchain)
 205                                 first_callchain = false;
 206                         else
 207                                 fputc(',', out);
 208
 209                         ok = thread__find_symbol(al.thread, cpumode, ip, &tal);
 210                         output_sample_callchain_entry(tool, ip, ok ? &tal : NULL);
 211                 }
 212         } else {
 213                 output_sample_callchain_entry(tool, sample->ip, &al);
 214         }
 215         output_json_format(out, false, 3, "]");
 216
 217         output_json_format(out, false, 2, "}");
 218         return 0;
 219 }
 220
 221 static void output_headers(struct perf_session *session, struct convert_json *c)
 222 {
 223         struct stat st;
 224         struct perf_header *header = &session->header;
 225         int ret;
 226         int fd = perf_data__fd(session->data);
 227         int i;
 228         FILE *out = c->out;
 229
 230         output_json_key_format(out, false, 2, "header-version", "%u", header->version);
 231
 232         ret = fstat(fd, &st);
 233         if (ret >= 0) {
 234                 time_t stctime = st.st_mtime;
 235                 char buf[256];
 236
 237                 strftime(buf, sizeof(buf), "%FT%TZ", gmtime(&stctime));
 238                 output_json_key_string(out, true, 2, "captured-on", buf);
 239         } else {
 240                 pr_debug("Failed to get mtime of source file, not writing captured-on");
 241         }
 242
 243         output_json_key_format(out, true, 2, "data-offset", "%" PRIu64, header->data_offset);
 244         output_json_key_format(out, true, 2, "data-size", "%" PRIu64, header->data_size);
 245         output_json_key_format(out, true, 2, "feat-offset", "%" PRIu64, header->feat_offset);
 246
 247         output_json_key_string(out, true, 2, "hostname", header->env.hostname);
 248         output_json_key_string(out, true, 2, "os-release", header->env.os_release);
 249         output_json_key_string(out, true, 2, "arch", header->env.arch);
 250
 251         output_json_key_string(out, true, 2, "cpu-desc", header->env.cpu_desc);
 252         output_json_key_string(out, true, 2, "cpuid", header->env.cpuid);
 253         output_json_key_format(out, true, 2, "nrcpus-online", "%u", header->env.nr_cpus_online);
 254         output_json_key_format(out, true, 2, "nrcpus-avail", "%u", header->env.nr_cpus_avail);
 255
 256         if (header->env.clock.enabled) {
 257                 output_json_key_format(out, true, 2, "clockid",
 258                                 "%u", header->env.clock.clockid);
 259                 output_json_key_format(out, true, 2, "clock-time",
 260                                 "%" PRIu64, header->env.clock.clockid_ns);
 261                 output_json_key_format(out, true, 2, "real-time",
 262                                 "%" PRIu64, header->env.clock.tod_ns);
 263         }
 264
 265         output_json_key_string(out, true, 2, "perf-version", header->env.version);
 266
 267         output_json_key_format(out, true, 2, "cmdline", "[");
 268         for (i = 0; i < header->env.nr_cmdline; i++) {
 269                 output_json_delimiters(out, i != 0, 3);
 270                 output_json_string(c->out, header->env.cmdline_argv[i]);
 271         }
 272         output_json_format(out, false, 2, "]");
 273 }
 274
 275 int bt_convert__perf2json(const char *input_name, const char *output_name,
 276                 struct perf_data_convert_opts *opts __maybe_unused)
 277 {
 278         struct perf_session *session;
 279         int fd;
 280         int ret = -1;
 281
 282         struct convert_json c = {
 283                 .tool = {
 284                         .sample         = process_sample_event,
 285                         .mmap           = perf_event__process_mmap,
 286                         .mmap2          = perf_event__process_mmap2,
 287                         .comm           = perf_event__process_comm,
 288                         .namespaces     = perf_event__process_namespaces,
 289                         .cgroup         = perf_event__process_cgroup,
 290                         .exit           = perf_event__process_exit,
 291                         .fork           = perf_event__process_fork,
 292                         .lost           = perf_event__process_lost,
 293                         .tracing_data   = perf_event__process_tracing_data,
 294                         .build_id       = perf_event__process_build_id,
 295                         .id_index       = perf_event__process_id_index,
 296                         .auxtrace_info  = perf_event__process_auxtrace_info,
 297                         .auxtrace       = perf_event__process_auxtrace,
 298                         .event_update   = perf_event__process_event_update,
 299                         .ordered_events = true,
 300                         .ordering_requires_timestamps = true,
 301                 },
 302                 .first = true,
 303                 .events_count = 0,
 304         };
 305
 306         struct perf_data data = {
 307                 .mode = PERF_DATA_MODE_READ,
 308                 .path = input_name,
 309                 .force = opts->force,
 310         };
 311
 312         if (opts->all) {
 313                 pr_err("--all is currently unsupported for JSON output.\n");
 314                 goto err;
 315         }
 316         if (opts->tod) {
 317                 pr_err("--tod is currently unsupported for JSON output.\n");
 318                 goto err;
 319         }
 320
 321         fd = open(output_name, O_CREAT | O_WRONLY | (opts->force ? O_TRUNC : O_EXCL), 0666);
 322         if (fd == -1) {
 323                 if (errno == EEXIST)
 324                         pr_err("Output file exists. Use --force to overwrite it.\n");
 325                 else
 326                         pr_err("Error opening output file!\n");
 327                 goto err;
 328         }
 329
 330         c.out = fdopen(fd, "w");
 331         if (!c.out) {
 332                 fprintf(stderr, "Error opening output file!\n");
 333                 close(fd);
 334                 goto err;
 335         }
 336
 337         session = perf_session__new(&data, &c.tool);
 338         if (IS_ERR(session)) {
 339                 fprintf(stderr, "Error creating perf session!\n");
 340                 goto err_fclose;
 341         }
 342
 343         if (symbol__init(&session->header.env) < 0) {
 344                 fprintf(stderr, "Symbol init error!\n");
 345                 goto err_session_delete;
 346         }
 347
 348         // The opening brace is printed manually because it isn't delimited from a
 349         // previous value (i.e. we don't want a leading newline)
 350         fputc('{', c.out);
 351
 352         // Version number for future-proofing. Most additions should be able to be
 353         // done in a backwards-compatible way so this should only need to be bumped
 354         // if some major breaking change must be made.
 355         output_json_format(c.out, false, 1, "\"linux-perf-json-version\": 1");
 356
 357         // Output headers
 358         output_json_format(c.out, true, 1, "\"headers\": {");
 359         output_headers(session, &c);
 360         output_json_format(c.out, false, 1, "}");
 361
 362         // Output samples
 363         output_json_format(c.out, true, 1, "\"samples\": [");
 364         perf_session__process_events(session);
 365         output_json_format(c.out, false, 1, "]");
 366         output_json_format(c.out, false, 0, "}");
 367         fputc('\n', c.out);
 368
 369         fprintf(stderr,
 370                         "[ perf data convert: Converted '%s' into JSON data '%s' ]\n",
 371                         data.path, output_name);
 372
 373         fprintf(stderr,
 374                         "[ perf data convert: Converted and wrote %.3f MB (%" PRIu64 " samples) ]\n",
 375                         (ftell(c.out)) / 1024.0 / 1024.0, c.events_count);
 376
 377         ret = 0;
 378 err_session_delete:
 379         perf_session__delete(session);
 380 err_fclose:
 381         fclose(c.out);
 382 err:
 383         return ret;
 384 }