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 <traceevent/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(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;
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(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
320	struct convert_json c = {
321		.tool = {
322			.sample         = process_sample_event,
323			.mmap           = perf_event__process_mmap,
324			.mmap2          = perf_event__process_mmap2,
325			.comm           = perf_event__process_comm,
326			.namespaces     = perf_event__process_namespaces,
327			.cgroup         = perf_event__process_cgroup,
328			.exit           = perf_event__process_exit,
329			.fork           = perf_event__process_fork,
330			.lost           = perf_event__process_lost,
331#ifdef HAVE_LIBTRACEEVENT
332			.tracing_data   = perf_event__process_tracing_data,
333#endif
334			.build_id       = perf_event__process_build_id,
335			.id_index       = perf_event__process_id_index,
336			.auxtrace_info  = perf_event__process_auxtrace_info,
337			.auxtrace       = perf_event__process_auxtrace,
338			.event_update   = perf_event__process_event_update,
339			.ordered_events = true,
340			.ordering_requires_timestamps = true,
341		},
342		.first = true,
343		.events_count = 0,
344	};
345
346	struct perf_data data = {
347		.mode = PERF_DATA_MODE_READ,
348		.path = input_name,
349		.force = opts->force,
350	};
351
352	if (opts->all) {
353		pr_err("--all is currently unsupported for JSON output.\n");
354		goto err;
355	}
356	if (opts->tod) {
357		pr_err("--tod is currently unsupported for JSON output.\n");
358		goto err;
359	}
360
361	fd = open(output_name, O_CREAT | O_WRONLY | (opts->force ? O_TRUNC : O_EXCL), 0666);
362	if (fd == -1) {
363		if (errno == EEXIST)
364			pr_err("Output file exists. Use --force to overwrite it.\n");
365		else
366			pr_err("Error opening output file!\n");
367		goto err;
368	}
369
370	c.out = fdopen(fd, "w");
371	if (!c.out) {
372		fprintf(stderr, "Error opening output file!\n");
373		close(fd);
374		goto err;
375	}
376
377	session = perf_session__new(&data, &c.tool);
378	if (IS_ERR(session)) {
379		fprintf(stderr, "Error creating perf session!\n");
380		goto err_fclose;
381	}
382
383	if (symbol__init(&session->header.env) < 0) {
384		fprintf(stderr, "Symbol init error!\n");
385		goto err_session_delete;
386	}
387
388	// The opening brace is printed manually because it isn't delimited from a
389	// previous value (i.e. we don't want a leading newline)
390	fputc('{', c.out);
391
392	// Version number for future-proofing. Most additions should be able to be
393	// done in a backwards-compatible way so this should only need to be bumped
394	// if some major breaking change must be made.
395	output_json_format(c.out, false, 1, "\"linux-perf-json-version\": 1");
396
397	// Output headers
398	output_json_format(c.out, true, 1, "\"headers\": {");
399	output_headers(session, &c);
400	output_json_format(c.out, false, 1, "}");
401
402	// Output samples
403	output_json_format(c.out, true, 1, "\"samples\": [");
404	perf_session__process_events(session);
405	output_json_format(c.out, false, 1, "]");
406	output_json_format(c.out, false, 0, "}");
407	fputc('\n', c.out);
408
409	fprintf(stderr,
410			"[ perf data convert: Converted '%s' into JSON data '%s' ]\n",
411			data.path, output_name);
412
413	fprintf(stderr,
414			"[ perf data convert: Converted and wrote %.3f MB (%" PRIu64 " samples) ]\n",
415			(ftell(c.out)) / 1024.0 / 1024.0, c.events_count);
416
417	ret = 0;
418err_session_delete:
419	perf_session__delete(session);
420err_fclose:
421	fclose(c.out);
422err:
423	return ret;
424}
425