// SPDX-License-Identifier: GPL-2.0-only
/*
 * JSON export.
 *
 * Copyright (C) 2021, CodeWeavers Inc. <nfraser@codeweavers.com>
 */

#include "data-convert.h"

#include <fcntl.h>
#include <inttypes.h>
#include <sys/stat.h>
#include <unistd.h>

#include "linux/compiler.h"
#include "linux/err.h"
#include "util/auxtrace.h"
#include "util/debug.h"
#include "util/dso.h"
#include "util/event.h"
#include "util/evsel.h"
#include "util/evlist.h"
#include "util/header.h"
#include "util/map.h"
#include "util/session.h"
#include "util/symbol.h"
#include "util/thread.h"
#include "util/time-utils.h"
#include "util/tool.h"

#ifdef HAVE_LIBTRACEEVENT
#include <event-parse.h>
#endif

struct convert_json {
        struct perf_tool tool;
        FILE *out;
        bool first;
        struct perf_time_interval *ptime_range;
        int range_size;
        int range_num;

        u64 events_count;
        u64 skipped;
};

// Outputs a JSON-encoded string surrounded by quotes with characters escaped.
static void output_json_string(FILE *out, const char *s)
{
        fputc('"', out);
        if (!s)
                goto out;

        while (*s) {
                switch (*s) {

                // required escapes with special forms as per RFC 8259
                case '"':  fputs("\\\"", out); break;
                case '\\': fputs("\\\\", out); break;
                case '\b': fputs("\\b", out);  break;
                case '\f': fputs("\\f", out);  break;
                case '\n': fputs("\\n", out);  break;
                case '\r': fputs("\\r", out);  break;
                case '\t': fputs("\\t", out);  break;

                default:
                        // all other control characters must be escaped by hex code
                        if (*s <= 0x1f)
                                fprintf(out, "\\u%04x", *s);
                        else
                                fputc(*s, out);
                        break;
                }

                ++s;
        }
out:
        fputc('"', out);
}

// Outputs an optional comma, newline and indentation to delimit a new value
// from the previous one in a JSON object or array.
static void output_json_delimiters(FILE *out, bool comma, int depth)
{
        int i;

        if (comma)
                fputc(',', out);
        fputc('\n', out);
        for (i = 0; i < depth; ++i)
                fputc('\t', out);
}

// Outputs a printf format string (with delimiter) as a JSON value.
__printf(4, 5)
static void output_json_format(FILE *out, bool comma, int depth, const char *format, ...)
{
        va_list args;

        output_json_delimiters(out, comma, depth);
        va_start(args, format);
        vfprintf(out,  format, args);
        va_end(args);
}

// Outputs a JSON key-value pair where the value is a string.
static void output_json_key_string(FILE *out, bool comma, int depth,
                const char *key, const char *value)
{
        output_json_delimiters(out, comma, depth);
        output_json_string(out, key);
        fputs(": ", out);
        output_json_string(out, value);
}

// Outputs a JSON key-value pair where the value is a printf format string.
__printf(5, 6)
static void output_json_key_format(FILE *out, bool comma, int depth,
                const char *key, const char *format, ...)
{
        va_list args;

        output_json_delimiters(out, comma, depth);
        output_json_string(out, key);
        fputs(": ", out);
        va_start(args, format);
        vfprintf(out,  format, args);
        va_end(args);
}

static void output_sample_callchain_entry(const struct perf_tool *tool,
                u64 ip, struct addr_location *al)
{
        struct convert_json *c = container_of(tool, struct convert_json, tool);
        FILE *out = c->out;

        output_json_format(out, false, 4, "{");
        output_json_key_format(out, false, 5, "ip", "\"0x%" PRIx64 "\"", ip);

        if (al && al->sym && al->sym->namelen) {
                struct dso *dso = al->map ? map__dso(al->map) : NULL;

                fputc(',', out);
                output_json_key_string(out, false, 5, "symbol", al->sym->name);

                if (dso) {
                        const char *dso_name = dso__short_name(dso);

                        if (dso_name && strlen(dso_name) > 0) {
                                fputc(',', out);
                                output_json_key_string(out, false, 5, "dso", dso_name);
                        }
                }
        }

        output_json_format(out, false, 4, "}");
}

static int process_sample_event(const struct perf_tool *tool,
                                union perf_event *event __maybe_unused,
                                struct perf_sample *sample,
                                struct evsel *evsel __maybe_unused,
                                struct machine *machine)
{
        struct convert_json *c = container_of(tool, struct convert_json, tool);
        FILE *out = c->out;
        struct addr_location al;
        u64 sample_type = __evlist__combined_sample_type(evsel->evlist);
        u8 cpumode = PERF_RECORD_MISC_USER;

        addr_location__init(&al);
        if (machine__resolve(machine, &al, sample) < 0) {
                pr_err("Sample resolution failed!\n");
                addr_location__exit(&al);
                return -1;
        }

        if (perf_time__ranges_skip_sample(c->ptime_range, c->range_num, sample->time)) {
                ++c->skipped;
                return 0;
        }

        ++c->events_count;

        if (c->first)
                c->first = false;
        else
                fputc(',', out);
        output_json_format(out, false, 2, "{");

        output_json_key_format(out, false, 3, "timestamp", "%" PRIi64, sample->time);
        output_json_key_format(out, true, 3, "pid", "%i", thread__pid(al.thread));
        output_json_key_format(out, true, 3, "tid", "%i", thread__tid(al.thread));

        if ((sample_type & PERF_SAMPLE_CPU))
                output_json_key_format(out, true, 3, "cpu", "%i", sample->cpu);
        else if (thread__cpu(al.thread) >= 0)
                output_json_key_format(out, true, 3, "cpu", "%i", thread__cpu(al.thread));

        output_json_key_string(out, true, 3, "comm", thread__comm_str(al.thread));

        output_json_key_format(out, true, 3, "callchain", "[");
        if (sample->callchain) {
                unsigned int i;
                bool ok;
                bool first_callchain = true;

                for (i = 0; i < sample->callchain->nr; ++i) {
                        u64 ip = sample->callchain->ips[i];
                        struct addr_location tal;

                        if (ip >= PERF_CONTEXT_MAX) {
                                switch (ip) {
                                case PERF_CONTEXT_HV:
                                        cpumode = PERF_RECORD_MISC_HYPERVISOR;
                                        break;
                                case PERF_CONTEXT_KERNEL:
                                        cpumode = PERF_RECORD_MISC_KERNEL;
                                        break;
                                case PERF_CONTEXT_USER:
                                        cpumode = PERF_RECORD_MISC_USER;
                                        break;
                                default:
                                        pr_debug("invalid callchain context: %"
                                                        PRId64 "\n", (s64) ip);
                                        break;
                                }
                                continue;
                        }

                        if (first_callchain)
                                first_callchain = false;
                        else
                                fputc(',', out);

                        addr_location__init(&tal);
                        ok = thread__find_symbol(al.thread, cpumode, ip, &tal);
                        output_sample_callchain_entry(tool, ip, ok ? &tal : NULL);
                        addr_location__exit(&tal);
                }
        } else {
                output_sample_callchain_entry(tool, sample->ip, &al);
        }
        output_json_format(out, false, 3, "]");

#ifdef HAVE_LIBTRACEEVENT
        if (sample->raw_data) {
                struct tep_event *tp_format = evsel__tp_format(evsel);
                struct tep_format_field **fields = tp_format ? tep_event_fields(tp_format) : NULL;

                if (fields) {
                        int i = 0;

                        while (fields[i]) {
                                struct trace_seq s;

                                trace_seq_init(&s);
                                tep_print_field(&s, sample->raw_data, fields[i]);
                                output_json_key_string(out, true, 3, fields[i]->name, s.buffer);

                                i++;
                        }
                        free(fields);
                }
        }
#endif
        output_json_format(out, false, 2, "}");
        addr_location__exit(&al);
        return 0;
}

static void output_headers(struct perf_session *session, struct convert_json *c)
{
        struct stat st;
        const struct perf_header *header = &session->header;
        const struct perf_env *env = perf_session__env(session);
        int ret;
        int fd = perf_data__fd(session->data);
        int i;
        FILE *out = c->out;

        output_json_key_format(out, false, 2, "header-version", "%u", header->version);

        ret = fstat(fd, &st);
        if (ret >= 0) {
                time_t stctime = st.st_mtime;
                char buf[256];

                strftime(buf, sizeof(buf), "%FT%TZ", gmtime(&stctime));
                output_json_key_string(out, true, 2, "captured-on", buf);
        } else {
                pr_debug("Failed to get mtime of source file, not writing captured-on");
        }

        output_json_key_format(out, true, 2, "data-offset", "%" PRIu64, header->data_offset);
        output_json_key_format(out, true, 2, "data-size", "%" PRIu64, header->data_size);
        output_json_key_format(out, true, 2, "feat-offset", "%" PRIu64, header->feat_offset);

        output_json_key_string(out, true, 2, "hostname", env->hostname);
        output_json_key_string(out, true, 2, "os-release", env->os_release);
        output_json_key_string(out, true, 2, "arch", env->arch);

        if (env->cpu_desc)
                output_json_key_string(out, true, 2, "cpu-desc", env->cpu_desc);

        output_json_key_string(out, true, 2, "cpuid", env->cpuid);
        output_json_key_format(out, true, 2, "nrcpus-online", "%u", env->nr_cpus_online);
        output_json_key_format(out, true, 2, "nrcpus-avail", "%u", env->nr_cpus_avail);

        if (env->clock.enabled) {
                output_json_key_format(out, true, 2, "clockid",
                                "%u", env->clock.clockid);
                output_json_key_format(out, true, 2, "clock-time",
                                "%" PRIu64, env->clock.clockid_ns);
                output_json_key_format(out, true, 2, "real-time",
                                "%" PRIu64, env->clock.tod_ns);
        }

        output_json_key_string(out, true, 2, "perf-version", env->version);

        output_json_key_format(out, true, 2, "cmdline", "[");
        for (i = 0; i < env->nr_cmdline; i++) {
                output_json_delimiters(out, i != 0, 3);
                output_json_string(c->out, env->cmdline_argv[i]);
        }
        output_json_format(out, false, 2, "]");
}

static int process_feature_event(const struct perf_tool *tool __maybe_unused,
                                 struct perf_session *session,
                                 union perf_event *event)
{
        if (event->feat.feat_id < HEADER_LAST_FEATURE)
                return perf_event__process_feature(session, event);

        return 0;
}

int bt_convert__perf2json(const char *input_name, const char *output_name,
                struct perf_data_convert_opts *opts __maybe_unused)
{
        struct perf_session *session;
        int fd;
        int ret = -1;
        struct convert_json c = {
                .first = true,
                .events_count = 0,
                .ptime_range = NULL,
                .range_size = 0,
                .range_num = 0,
                .skipped = 0,
        };
        struct perf_data data = {
                .mode = PERF_DATA_MODE_READ,
                .path = input_name,
                .force = opts->force,
        };

        perf_tool__init(&c.tool, /*ordered_events=*/true);
        c.tool.sample         = process_sample_event;
        c.tool.mmap           = perf_event__process_mmap;
        c.tool.mmap2          = perf_event__process_mmap2;
        c.tool.comm           = perf_event__process_comm;
        c.tool.namespaces     = perf_event__process_namespaces;
        c.tool.cgroup         = perf_event__process_cgroup;
        c.tool.exit           = perf_event__process_exit;
        c.tool.fork           = perf_event__process_fork;
        c.tool.lost           = perf_event__process_lost;
#ifdef HAVE_LIBTRACEEVENT
        c.tool.tracing_data   = perf_event__process_tracing_data;
#endif
        c.tool.build_id       = perf_event__process_build_id;
        c.tool.id_index       = perf_event__process_id_index;
        c.tool.auxtrace_info  = perf_event__process_auxtrace_info;
        c.tool.auxtrace       = perf_event__process_auxtrace;
        c.tool.event_update   = perf_event__process_event_update;
        c.tool.attr           = perf_event__process_attr;
        c.tool.feature        = process_feature_event;
        c.tool.ordering_requires_timestamps = true;

        if (opts->all) {
                pr_err("--all is currently unsupported for JSON output.\n");
                goto err;
        }
        if (opts->tod) {
                pr_err("--tod is currently unsupported for JSON output.\n");
                goto err;
        }

        fd = open(output_name, O_CREAT | O_WRONLY | (opts->force ? O_TRUNC : O_EXCL), 0666);
        if (fd == -1) {
                if (errno == EEXIST)
                        pr_err("Output file exists. Use --force to overwrite it.\n");
                else
                        pr_err("Error opening output file!\n");
                goto err;
        }

        c.out = fdopen(fd, "w");
        if (!c.out) {
                fprintf(stderr, "Error opening output file!\n");
                close(fd);
                goto err;
        }

        session = perf_session__new(&data, &c.tool);
        if (IS_ERR(session)) {
                fprintf(stderr, "Error creating perf session!\n");
                goto err_fclose;
        }
        if (symbol__init(perf_session__env(session)) < 0) {
                fprintf(stderr, "Symbol init error!\n");
                goto err_session_delete;
        }

        if (opts->time_str) {
                ret = perf_time__parse_for_ranges(opts->time_str, session,
                                                  &c.ptime_range,
                                                  &c.range_size,
                                                  &c.range_num);
                if (ret < 0)
                        goto err_session_delete;
        }

        // The opening brace is printed manually because it isn't delimited from a
        // previous value (i.e. we don't want a leading newline)
        fputc('{', c.out);

        // Version number for future-proofing. Most additions should be able to be
        // done in a backwards-compatible way so this should only need to be bumped
        // if some major breaking change must be made.
        output_json_format(c.out, false, 1, "\"linux-perf-json-version\": 1");

        // Output headers
        output_json_format(c.out, true, 1, "\"headers\": {");
        output_headers(session, &c);
        output_json_format(c.out, false, 1, "}");

        // Output samples
        output_json_format(c.out, true, 1, "\"samples\": [");
        perf_session__process_events(session);
        output_json_format(c.out, false, 1, "]");
        output_json_format(c.out, false, 0, "}");
        fputc('\n', c.out);

        fprintf(stderr, "[ perf data convert: Converted '%s' into JSON data '%s' ]\n",
                data.path, output_name);

        fprintf(stderr,
                "[ perf data convert: Converted and wrote %.3f MB (%" PRIu64 " samples) ]\n",
                (ftell(c.out)) / 1024.0 / 1024.0, c.events_count);

        if (c.skipped) {
                fprintf(stderr, "[ perf data convert: Skipped %" PRIu64 " samples ]\n",
                        c.skipped);
        }

        ret = 0;

        if (c.ptime_range)
                zfree(&c.ptime_range);

err_session_delete:
        perf_session__delete(session);
err_fclose:
        fclose(c.out);
err:
        return ret;
}