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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#ifdef HAVE_LIBTRACEEVENT
31#include <event-parse.h>
32#endif
33
34struct convert_json {
35 struct perf_tool tool;
36 FILE *out;
37 bool first;
38 u64 events_count;
39};
40
41// Outputs a JSON-encoded string surrounded by quotes with characters escaped.
42static void output_json_string(FILE *out, const char *s)
43{
44 fputc('"', out);
45 while (*s) {
46 switch (*s) {
47
48 // required escapes with special forms as per RFC 8259
49 case '"': fputs("\\\"", out); break;
50 case '\\': fputs("\\\\", out); break;
51 case '\b': fputs("\\b", out); break;
52 case '\f': fputs("\\f", out); break;
53 case '\n': fputs("\\n", out); break;
54 case '\r': fputs("\\r", out); break;
55 case '\t': fputs("\\t", out); break;
56
57 default:
58 // all other control characters must be escaped by hex code
59 if (*s <= 0x1f)
60 fprintf(out, "\\u%04x", *s);
61 else
62 fputc(*s, out);
63 break;
64 }
65
66 ++s;
67 }
68 fputc('"', out);
69}
70
71// Outputs an optional comma, newline and indentation to delimit a new value
72// from the previous one in a JSON object or array.
73static void output_json_delimiters(FILE *out, bool comma, int depth)
74{
75 int i;
76
77 if (comma)
78 fputc(',', out);
79 fputc('\n', out);
80 for (i = 0; i < depth; ++i)
81 fputc('\t', out);
82}
83
84// Outputs a printf format string (with delimiter) as a JSON value.
85__printf(4, 5)
86static void output_json_format(FILE *out, bool comma, int depth, const char *format, ...)
87{
88 va_list args;
89
90 output_json_delimiters(out, comma, depth);
91 va_start(args, format);
92 vfprintf(out, format, args);
93 va_end(args);
94}
95
96// Outputs a JSON key-value pair where the value is a string.
97static void output_json_key_string(FILE *out, bool comma, int depth,
98 const char *key, const char *value)
99{
100 output_json_delimiters(out, comma, depth);
101 output_json_string(out, key);
102 fputs(": ", out);
103 output_json_string(out, value);
104}
105
106// Outputs a JSON key-value pair where the value is a printf format string.
107__printf(5, 6)
108static void output_json_key_format(FILE *out, bool comma, int depth,
109 const char *key, const char *format, ...)
110{
111 va_list args;
112
113 output_json_delimiters(out, comma, depth);
114 output_json_string(out, key);
115 fputs(": ", out);
116 va_start(args, format);
117 vfprintf(out, format, args);
118 va_end(args);
119}
120
121static void output_sample_callchain_entry(const struct perf_tool *tool,
122 u64 ip, struct addr_location *al)
123{
124 struct convert_json *c = container_of(tool, struct convert_json, tool);
125 FILE *out = c->out;
126
127 output_json_format(out, false, 4, "{");
128 output_json_key_format(out, false, 5, "ip", "\"0x%" PRIx64 "\"", ip);
129
130 if (al && al->sym && al->sym->namelen) {
131 struct dso *dso = al->map ? map__dso(al->map) : NULL;
132
133 fputc(',', out);
134 output_json_key_string(out, false, 5, "symbol", al->sym->name);
135
136 if (dso) {
137 const char *dso_name = dso__short_name(dso);
138
139 if (dso_name && strlen(dso_name) > 0) {
140 fputc(',', out);
141 output_json_key_string(out, false, 5, "dso", dso_name);
142 }
143 }
144 }
145
146 output_json_format(out, false, 4, "}");
147}
148
149static int process_sample_event(const struct perf_tool *tool,
150 union perf_event *event __maybe_unused,
151 struct perf_sample *sample,
152 struct evsel *evsel __maybe_unused,
153 struct machine *machine)
154{
155 struct convert_json *c = container_of(tool, struct convert_json, tool);
156 FILE *out = c->out;
157 struct addr_location al;
158 u64 sample_type = __evlist__combined_sample_type(evsel->evlist);
159 u8 cpumode = PERF_RECORD_MISC_USER;
160
161 addr_location__init(&al);
162 if (machine__resolve(machine, &al, sample) < 0) {
163 pr_err("Sample resolution failed!\n");
164 addr_location__exit(&al);
165 return -1;
166 }
167
168 ++c->events_count;
169
170 if (c->first)
171 c->first = false;
172 else
173 fputc(',', out);
174 output_json_format(out, false, 2, "{");
175
176 output_json_key_format(out, false, 3, "timestamp", "%" PRIi64, sample->time);
177 output_json_key_format(out, true, 3, "pid", "%i", thread__pid(al.thread));
178 output_json_key_format(out, true, 3, "tid", "%i", thread__tid(al.thread));
179
180 if ((sample_type & PERF_SAMPLE_CPU))
181 output_json_key_format(out, true, 3, "cpu", "%i", sample->cpu);
182 else if (thread__cpu(al.thread) >= 0)
183 output_json_key_format(out, true, 3, "cpu", "%i", thread__cpu(al.thread));
184
185 output_json_key_string(out, true, 3, "comm", thread__comm_str(al.thread));
186
187 output_json_key_format(out, true, 3, "callchain", "[");
188 if (sample->callchain) {
189 unsigned int i;
190 bool ok;
191 bool first_callchain = true;
192
193 for (i = 0; i < sample->callchain->nr; ++i) {
194 u64 ip = sample->callchain->ips[i];
195 struct addr_location tal;
196
197 if (ip >= PERF_CONTEXT_MAX) {
198 switch (ip) {
199 case PERF_CONTEXT_HV:
200 cpumode = PERF_RECORD_MISC_HYPERVISOR;
201 break;
202 case PERF_CONTEXT_KERNEL:
203 cpumode = PERF_RECORD_MISC_KERNEL;
204 break;
205 case PERF_CONTEXT_USER:
206 cpumode = PERF_RECORD_MISC_USER;
207 break;
208 default:
209 pr_debug("invalid callchain context: %"
210 PRId64 "\n", (s64) ip);
211 break;
212 }
213 continue;
214 }
215
216 if (first_callchain)
217 first_callchain = false;
218 else
219 fputc(',', out);
220
221 addr_location__init(&tal);
222 ok = thread__find_symbol(al.thread, cpumode, ip, &tal);
223 output_sample_callchain_entry(tool, ip, ok ? &tal : NULL);
224 addr_location__exit(&tal);
225 }
226 } else {
227 output_sample_callchain_entry(tool, sample->ip, &al);
228 }
229 output_json_format(out, false, 3, "]");
230
231#ifdef HAVE_LIBTRACEEVENT
232 if (sample->raw_data) {
233 int i;
234 struct tep_format_field **fields;
235
236 fields = tep_event_fields(evsel->tp_format);
237 if (fields) {
238 i = 0;
239 while (fields[i]) {
240 struct trace_seq s;
241
242 trace_seq_init(&s);
243 tep_print_field(&s, sample->raw_data, fields[i]);
244 output_json_key_string(out, true, 3, fields[i]->name, s.buffer);
245
246 i++;
247 }
248 free(fields);
249 }
250 }
251#endif
252 output_json_format(out, false, 2, "}");
253 addr_location__exit(&al);
254 return 0;
255}
256
257static void output_headers(struct perf_session *session, struct convert_json *c)
258{
259 struct stat st;
260 struct perf_header *header = &session->header;
261 int ret;
262 int fd = perf_data__fd(session->data);
263 int i;
264 FILE *out = c->out;
265
266 output_json_key_format(out, false, 2, "header-version", "%u", header->version);
267
268 ret = fstat(fd, &st);
269 if (ret >= 0) {
270 time_t stctime = st.st_mtime;
271 char buf[256];
272
273 strftime(buf, sizeof(buf), "%FT%TZ", gmtime(&stctime));
274 output_json_key_string(out, true, 2, "captured-on", buf);
275 } else {
276 pr_debug("Failed to get mtime of source file, not writing captured-on");
277 }
278
279 output_json_key_format(out, true, 2, "data-offset", "%" PRIu64, header->data_offset);
280 output_json_key_format(out, true, 2, "data-size", "%" PRIu64, header->data_size);
281 output_json_key_format(out, true, 2, "feat-offset", "%" PRIu64, header->feat_offset);
282
283 output_json_key_string(out, true, 2, "hostname", header->env.hostname);
284 output_json_key_string(out, true, 2, "os-release", header->env.os_release);
285 output_json_key_string(out, true, 2, "arch", header->env.arch);
286
287 if (header->env.cpu_desc)
288 output_json_key_string(out, true, 2, "cpu-desc", header->env.cpu_desc);
289
290 output_json_key_string(out, true, 2, "cpuid", header->env.cpuid);
291 output_json_key_format(out, true, 2, "nrcpus-online", "%u", header->env.nr_cpus_online);
292 output_json_key_format(out, true, 2, "nrcpus-avail", "%u", header->env.nr_cpus_avail);
293
294 if (header->env.clock.enabled) {
295 output_json_key_format(out, true, 2, "clockid",
296 "%u", header->env.clock.clockid);
297 output_json_key_format(out, true, 2, "clock-time",
298 "%" PRIu64, header->env.clock.clockid_ns);
299 output_json_key_format(out, true, 2, "real-time",
300 "%" PRIu64, header->env.clock.tod_ns);
301 }
302
303 output_json_key_string(out, true, 2, "perf-version", header->env.version);
304
305 output_json_key_format(out, true, 2, "cmdline", "[");
306 for (i = 0; i < header->env.nr_cmdline; i++) {
307 output_json_delimiters(out, i != 0, 3);
308 output_json_string(c->out, header->env.cmdline_argv[i]);
309 }
310 output_json_format(out, false, 2, "]");
311}
312
313int bt_convert__perf2json(const char *input_name, const char *output_name,
314 struct perf_data_convert_opts *opts __maybe_unused)
315{
316 struct perf_session *session;
317 int fd;
318 int ret = -1;
319 struct convert_json c = {
320 .first = true,
321 .events_count = 0,
322 };
323 struct perf_data data = {
324 .mode = PERF_DATA_MODE_READ,
325 .path = input_name,
326 .force = opts->force,
327 };
328
329 perf_tool__init(&c.tool, /*ordered_events=*/true);
330 c.tool.sample = process_sample_event;
331 c.tool.mmap = perf_event__process_mmap;
332 c.tool.mmap2 = perf_event__process_mmap2;
333 c.tool.comm = perf_event__process_comm;
334 c.tool.namespaces = perf_event__process_namespaces;
335 c.tool.cgroup = perf_event__process_cgroup;
336 c.tool.exit = perf_event__process_exit;
337 c.tool.fork = perf_event__process_fork;
338 c.tool.lost = perf_event__process_lost;
339#ifdef HAVE_LIBTRACEEVENT
340 c.tool.tracing_data = perf_event__process_tracing_data;
341#endif
342 c.tool.build_id = perf_event__process_build_id;
343 c.tool.id_index = perf_event__process_id_index;
344 c.tool.auxtrace_info = perf_event__process_auxtrace_info;
345 c.tool.auxtrace = perf_event__process_auxtrace;
346 c.tool.event_update = perf_event__process_event_update;
347 c.tool.ordering_requires_timestamps = true;
348
349 if (opts->all) {
350 pr_err("--all is currently unsupported for JSON output.\n");
351 goto err;
352 }
353 if (opts->tod) {
354 pr_err("--tod is currently unsupported for JSON output.\n");
355 goto err;
356 }
357
358 fd = open(output_name, O_CREAT | O_WRONLY | (opts->force ? O_TRUNC : O_EXCL), 0666);
359 if (fd == -1) {
360 if (errno == EEXIST)
361 pr_err("Output file exists. Use --force to overwrite it.\n");
362 else
363 pr_err("Error opening output file!\n");
364 goto err;
365 }
366
367 c.out = fdopen(fd, "w");
368 if (!c.out) {
369 fprintf(stderr, "Error opening output file!\n");
370 close(fd);
371 goto err;
372 }
373
374 session = perf_session__new(&data, &c.tool);
375 if (IS_ERR(session)) {
376 fprintf(stderr, "Error creating perf session!\n");
377 goto err_fclose;
378 }
379
380 if (symbol__init(&session->header.env) < 0) {
381 fprintf(stderr, "Symbol init error!\n");
382 goto err_session_delete;
383 }
384
385 // The opening brace is printed manually because it isn't delimited from a
386 // previous value (i.e. we don't want a leading newline)
387 fputc('{', c.out);
388
389 // Version number for future-proofing. Most additions should be able to be
390 // done in a backwards-compatible way so this should only need to be bumped
391 // if some major breaking change must be made.
392 output_json_format(c.out, false, 1, "\"linux-perf-json-version\": 1");
393
394 // Output headers
395 output_json_format(c.out, true, 1, "\"headers\": {");
396 output_headers(session, &c);
397 output_json_format(c.out, false, 1, "}");
398
399 // Output samples
400 output_json_format(c.out, true, 1, "\"samples\": [");
401 perf_session__process_events(session);
402 output_json_format(c.out, false, 1, "]");
403 output_json_format(c.out, false, 0, "}");
404 fputc('\n', c.out);
405
406 fprintf(stderr,
407 "[ perf data convert: Converted '%s' into JSON data '%s' ]\n",
408 data.path, output_name);
409
410 fprintf(stderr,
411 "[ perf data convert: Converted and wrote %.3f MB (%" PRIu64 " samples) ]\n",
412 (ftell(c.out)) / 1024.0 / 1024.0, c.events_count);
413
414 ret = 0;
415err_session_delete:
416 perf_session__delete(session);
417err_fclose:
418 fclose(c.out);
419err:
420 return ret;
421}
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
30struct 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.
38static 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.
69static 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)
82static 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.
93static 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)
104static 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
117static 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
143static 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
221static 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
275int 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, false, &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;
378err_session_delete:
379 perf_session__delete(session);
380err_fclose:
381 fclose(c.out);
382err:
383 return ret;
384}