// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <linux/perf_event.h>
#include <linux/string.h>
#include <linux/zalloc.h>
#include <internal/lib.h>
#include <perf/event.h>
#include <symbol/kallsyms.h>
#include "bpf-event.h"
#include "bpf-utils.h"
#include "debug.h"
#include "dso.h"
#include "symbol.h"
#include "machine.h"
#include "env.h"
#include "session.h"
#include "map.h"
#include "evlist.h"
#include "record.h"
#include "util/synthetic-events.h"

static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
{
        int ret = 0;
        size_t i;

        for (i = 0; i < len; i++)
                ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
        return ret;
}

static int machine__process_bpf_event_load(struct machine *machine,
                                           union perf_event *event,
                                           struct perf_sample *sample __maybe_unused)
{
        struct bpf_prog_info_node *info_node;
        struct perf_env *env = machine->env;
        struct perf_bpil *info_linear;
        int id = event->bpf.id;
        unsigned int i;

        /* perf-record, no need to handle bpf-event */
        if (env == NULL)
                return 0;

        info_node = perf_env__find_bpf_prog_info(env, id);
        if (!info_node)
                return 0;
        info_linear = info_node->info_linear;

        for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
                u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
                u64 addr = addrs[i];
                struct map *map = maps__find(machine__kernel_maps(machine), addr);

                if (map) {
                        struct dso *dso = map__dso(map);

                        dso__set_binary_type(dso, DSO_BINARY_TYPE__BPF_PROG_INFO);
                        dso__bpf_prog(dso)->id = id;
                        dso__bpf_prog(dso)->sub_id = i;
                        dso__bpf_prog(dso)->env = env;
                        map__put(map);
                }
        }
        return 0;
}

int machine__process_bpf(struct machine *machine, union perf_event *event,
                         struct perf_sample *sample)
{
        if (dump_trace)
                perf_event__fprintf_bpf(event, stdout);

        switch (event->bpf.type) {
        case PERF_BPF_EVENT_PROG_LOAD:
                return machine__process_bpf_event_load(machine, event, sample);

        case PERF_BPF_EVENT_PROG_UNLOAD:
                /*
                 * Do not free bpf_prog_info and btf of the program here,
                 * as annotation still need them. They will be freed at
                 * the end of the session.
                 */
                break;
        default:
                pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
                break;
        }
        return 0;
}

static int perf_env__fetch_btf(struct perf_env *env,
                               u32 btf_id,
                               struct btf *btf)
{
        struct btf_node *node;
        u32 data_size;
        const void *data;

        data = btf__raw_data(btf, &data_size);

        node = malloc(data_size + sizeof(struct btf_node));
        if (!node)
                return -1;

        node->id = btf_id;
        node->data_size = data_size;
        memcpy(node->data, data, data_size);

        if (!perf_env__insert_btf(env, node)) {
                /* Insertion failed because of a duplicate. */
                free(node);
                return -1;
        }
        return 0;
}

static int synthesize_bpf_prog_name(char *buf, int size,
                                    struct bpf_prog_info *info,
                                    struct btf *btf,
                                    u32 sub_id)
{
        u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
        void *func_infos = (void *)(uintptr_t)(info->func_info);
        u32 sub_prog_cnt = info->nr_jited_ksyms;
        const struct bpf_func_info *finfo;
        const char *short_name = NULL;
        const struct btf_type *t;
        int name_len;

        name_len = snprintf(buf, size, "bpf_prog_");
        name_len += snprintf_hex(buf + name_len, size - name_len,
                                 prog_tags[sub_id], BPF_TAG_SIZE);
        if (btf) {
                finfo = func_infos + sub_id * info->func_info_rec_size;
                t = btf__type_by_id(btf, finfo->type_id);
                short_name = btf__name_by_offset(btf, t->name_off);
        } else if (sub_id == 0 && sub_prog_cnt == 1) {
                /* no subprog */
                if (info->name[0])
                        short_name = info->name;
        } else
                short_name = "F";
        if (short_name)
                name_len += snprintf(buf + name_len, size - name_len,
                                     "_%s", short_name);
        return name_len;
}

#ifdef HAVE_LIBBPF_STRINGS_SUPPORT

#define BPF_METADATA_PREFIX "bpf_metadata_"
#define BPF_METADATA_PREFIX_LEN (sizeof(BPF_METADATA_PREFIX) - 1)

static bool name_has_bpf_metadata_prefix(const char **s)
{
        if (strncmp(*s, BPF_METADATA_PREFIX, BPF_METADATA_PREFIX_LEN) != 0)
                return false;
        *s += BPF_METADATA_PREFIX_LEN;
        return true;
}

struct bpf_metadata_map {
        struct btf *btf;
        const struct btf_type *datasec;
        void *rodata;
        size_t rodata_size;
        unsigned int num_vars;
};

static int bpf_metadata_read_map_data(__u32 map_id, struct bpf_metadata_map *map)
{
        int map_fd;
        struct bpf_map_info map_info;
        __u32 map_info_len;
        int key;
        struct btf *btf;
        const struct btf_type *datasec;
        struct btf_var_secinfo *vsi;
        unsigned int vlen, vars;
        void *rodata;

        map_fd = bpf_map_get_fd_by_id(map_id);
        if (map_fd < 0)
                return -1;

        memset(&map_info, 0, sizeof(map_info));
        map_info_len = sizeof(map_info);
        if (bpf_obj_get_info_by_fd(map_fd, &map_info, &map_info_len) < 0)
                goto out_close;

        /* If it's not an .rodata map, don't bother. */
        if (map_info.type != BPF_MAP_TYPE_ARRAY ||
            map_info.key_size != sizeof(int) ||
            map_info.max_entries != 1 ||
            !map_info.btf_value_type_id ||
            !strstr(map_info.name, ".rodata")) {
                goto out_close;
        }

        btf = btf__load_from_kernel_by_id(map_info.btf_id);
        if (!btf)
                goto out_close;
        datasec = btf__type_by_id(btf, map_info.btf_value_type_id);
        if (!btf_is_datasec(datasec))
                goto out_free_btf;

        /*
         * If there aren't any variables with the "bpf_metadata_" prefix,
         * don't bother.
         */
        vlen = btf_vlen(datasec);
        vsi = btf_var_secinfos(datasec);
        vars = 0;
        for (unsigned int i = 0; i < vlen; i++, vsi++) {
                const struct btf_type *t_var = btf__type_by_id(btf, vsi->type);
                const char *name = btf__name_by_offset(btf, t_var->name_off);

                if (name_has_bpf_metadata_prefix(&name))
                        vars++;
        }
        if (vars == 0)
                goto out_free_btf;

        rodata = zalloc(map_info.value_size);
        if (!rodata)
                goto out_free_btf;
        key = 0;
        if (bpf_map_lookup_elem(map_fd, &key, rodata)) {
                free(rodata);
                goto out_free_btf;
        }
        close(map_fd);

        map->btf = btf;
        map->datasec = datasec;
        map->rodata = rodata;
        map->rodata_size = map_info.value_size;
        map->num_vars = vars;
        return 0;

out_free_btf:
        btf__free(btf);
out_close:
        close(map_fd);
        return -1;
}

struct format_btf_ctx {
        char *buf;
        size_t buf_size;
        size_t buf_idx;
};

static void format_btf_cb(void *arg, const char *fmt, va_list ap)
{
        int n;
        struct format_btf_ctx *ctx = (struct format_btf_ctx *)arg;

        n = vsnprintf(ctx->buf + ctx->buf_idx, ctx->buf_size - ctx->buf_idx,
                      fmt, ap);
        ctx->buf_idx += n;
        if (ctx->buf_idx >= ctx->buf_size)
                ctx->buf_idx = ctx->buf_size;
}

static void format_btf_variable(struct btf *btf, char *buf, size_t buf_size,
                                const struct btf_type *t, const void *btf_data)
{
        struct format_btf_ctx ctx = {
                .buf = buf,
                .buf_idx = 0,
                .buf_size = buf_size,
        };
        const struct btf_dump_type_data_opts opts = {
                .sz = sizeof(struct btf_dump_type_data_opts),
                .skip_names = 1,
                .compact = 1,
                .emit_strings = 1,
        };
        struct btf_dump *d;
        size_t btf_size;

        d = btf_dump__new(btf, format_btf_cb, &ctx, NULL);
        btf_size = btf__resolve_size(btf, t->type);
        btf_dump__dump_type_data(d, t->type, btf_data, btf_size, &opts);
        btf_dump__free(d);
}

static void bpf_metadata_fill_event(struct bpf_metadata_map *map,
                                    struct perf_record_bpf_metadata *bpf_metadata_event)
{
        struct btf_var_secinfo *vsi;
        unsigned int i, vlen;

        memset(bpf_metadata_event->prog_name, 0, BPF_PROG_NAME_LEN);
        vlen = btf_vlen(map->datasec);
        vsi = btf_var_secinfos(map->datasec);

        for (i = 0; i < vlen; i++, vsi++) {
                const struct btf_type *t_var = btf__type_by_id(map->btf,
                                                               vsi->type);
                const char *name = btf__name_by_offset(map->btf,
                                                       t_var->name_off);
                const __u64 nr_entries = bpf_metadata_event->nr_entries;
                struct perf_record_bpf_metadata_entry *entry;

                if (!name_has_bpf_metadata_prefix(&name))
                        continue;

                if (nr_entries >= (__u64)map->num_vars)
                        break;

                entry = &bpf_metadata_event->entries[nr_entries];
                memset(entry, 0, sizeof(*entry));
                snprintf(entry->key, BPF_METADATA_KEY_LEN, "%s", name);
                format_btf_variable(map->btf, entry->value,
                                    BPF_METADATA_VALUE_LEN, t_var,
                                    map->rodata + vsi->offset);
                bpf_metadata_event->nr_entries++;
        }
}

static void bpf_metadata_free_map_data(struct bpf_metadata_map *map)
{
        btf__free(map->btf);
        free(map->rodata);
}

static struct bpf_metadata *bpf_metadata_alloc(__u32 nr_prog_tags,
                                               __u32 nr_variables)
{
        struct bpf_metadata *metadata;
        size_t event_size;

        metadata = zalloc(sizeof(struct bpf_metadata));
        if (!metadata)
                return NULL;

        metadata->prog_names = zalloc(nr_prog_tags * sizeof(char *));
        if (!metadata->prog_names) {
                bpf_metadata_free(metadata);
                return NULL;
        }
        for (__u32 prog_index = 0; prog_index < nr_prog_tags; prog_index++) {
                metadata->prog_names[prog_index] = zalloc(BPF_PROG_NAME_LEN);
                if (!metadata->prog_names[prog_index]) {
                        bpf_metadata_free(metadata);
                        return NULL;
                }
                metadata->nr_prog_names++;
        }

        event_size = sizeof(metadata->event->bpf_metadata) +
            nr_variables * sizeof(metadata->event->bpf_metadata.entries[0]);
        metadata->event = zalloc(event_size);
        if (!metadata->event) {
                bpf_metadata_free(metadata);
                return NULL;
        }
        metadata->event->bpf_metadata = (struct perf_record_bpf_metadata) {
                .header = {
                        .type = PERF_RECORD_BPF_METADATA,
                        .size = event_size,
                },
                .nr_entries = 0,
        };

        return metadata;
}

static struct bpf_metadata *bpf_metadata_create(struct bpf_prog_info *info)
{
        struct bpf_metadata *metadata;
        const __u32 *map_ids = (__u32 *)(uintptr_t)info->map_ids;

        for (__u32 map_index = 0; map_index < info->nr_map_ids; map_index++) {
                struct bpf_metadata_map map;

                if (bpf_metadata_read_map_data(map_ids[map_index], &map) != 0)
                        continue;

                metadata = bpf_metadata_alloc(info->nr_prog_tags, map.num_vars);
                if (!metadata)
                        continue;

                bpf_metadata_fill_event(&map, &metadata->event->bpf_metadata);

                for (__u32 index = 0; index < info->nr_prog_tags; index++) {
                        synthesize_bpf_prog_name(metadata->prog_names[index],
                                                 BPF_PROG_NAME_LEN, info,
                                                 map.btf, index);
                }

                bpf_metadata_free_map_data(&map);

                return metadata;
        }

        return NULL;
}

static int synthesize_perf_record_bpf_metadata(const struct bpf_metadata *metadata,
                                               const struct perf_tool *tool,
                                               perf_event__handler_t process,
                                               struct machine *machine)
{
        const size_t event_size = metadata->event->header.size;
        union perf_event *event;
        int err = 0;

        event = zalloc(event_size + machine->id_hdr_size);
        if (!event)
                return -1;
        memcpy(event, metadata->event, event_size);
        memset((void *)event + event->header.size, 0, machine->id_hdr_size);
        event->header.size += machine->id_hdr_size;
        for (__u32 index = 0; index < metadata->nr_prog_names; index++) {
                memcpy(event->bpf_metadata.prog_name,
                       metadata->prog_names[index], BPF_PROG_NAME_LEN);
                err = perf_tool__process_synth_event(tool, event, machine,
                                                     process);
                if (err != 0)
                        break;
        }

        free(event);
        return err;
}

void bpf_metadata_free(struct bpf_metadata *metadata)
{
        if (metadata == NULL)
                return;
        for (__u32 index = 0; index < metadata->nr_prog_names; index++)
                free(metadata->prog_names[index]);
        free(metadata->prog_names);
        free(metadata->event);
        free(metadata);
}

#else /* HAVE_LIBBPF_STRINGS_SUPPORT */

static struct bpf_metadata *bpf_metadata_create(struct bpf_prog_info *info __maybe_unused)
{
        return NULL;
}

static int synthesize_perf_record_bpf_metadata(const struct bpf_metadata *metadata __maybe_unused,
                                               const struct perf_tool *tool __maybe_unused,
                                               perf_event__handler_t process __maybe_unused,
                                               struct machine *machine __maybe_unused)
{
        return 0;
}

void bpf_metadata_free(struct bpf_metadata *metadata __maybe_unused)
{
}

#endif /* HAVE_LIBBPF_STRINGS_SUPPORT */

struct bpf_metadata_final_ctx {
        const struct perf_tool *tool;
        perf_event__handler_t process;
        struct machine *machine;
};

static void synthesize_final_bpf_metadata_cb(struct bpf_prog_info_node *node,
                                             void *data)
{
        struct bpf_metadata_final_ctx *ctx = (struct bpf_metadata_final_ctx *)data;
        struct bpf_metadata *metadata = node->metadata;
        int err;

        if (metadata == NULL)
                return;
        err = synthesize_perf_record_bpf_metadata(metadata, ctx->tool,
                                                  ctx->process, ctx->machine);
        if (err != 0) {
                const char *prog_name = metadata->prog_names[0];

                if (prog_name != NULL)
                        pr_warning("Couldn't synthesize final BPF metadata for %s.\n", prog_name);
                else
                        pr_warning("Couldn't synthesize final BPF metadata.\n");
        }
        bpf_metadata_free(metadata);
        node->metadata = NULL;
}

void perf_event__synthesize_final_bpf_metadata(struct perf_session *session,
                                               perf_event__handler_t process)
{
        struct perf_env *env = &session->header.env;
        struct bpf_metadata_final_ctx ctx = {
                .tool = session->tool,
                .process = process,
                .machine = &session->machines.host,
        };

        perf_env__iterate_bpf_prog_info(env, synthesize_final_bpf_metadata_cb,
                                        &ctx);
}

/*
 * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 * one PERF_RECORD_KSYMBOL is generated for each sub program.
 *
 * Returns:
 *    0 for success;
 *   -1 for failures;
 *   -2 for lack of kernel support.
 */
static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
                                               perf_event__handler_t process,
                                               struct machine *machine,
                                               int fd,
                                               union perf_event *event,
                                               struct record_opts *opts)
{
        struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
        struct perf_record_bpf_event *bpf_event = &event->bpf;
        const struct perf_tool *tool = session->tool;
        struct bpf_prog_info_node *info_node;
        struct perf_bpil *info_linear;
        struct bpf_metadata *metadata;
        struct bpf_prog_info *info;
        struct btf *btf = NULL;
        struct perf_env *env;
        u32 sub_prog_cnt, i;
        int err = 0;
        u64 arrays;

        /*
         * for perf-record and perf-report use header.env;
         * otherwise, use global perf_env.
         */
        env = perf_session__env(session);

        arrays = 1UL << PERF_BPIL_JITED_KSYMS;
        arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
        arrays |= 1UL << PERF_BPIL_FUNC_INFO;
        arrays |= 1UL << PERF_BPIL_PROG_TAGS;
        arrays |= 1UL << PERF_BPIL_JITED_INSNS;
        arrays |= 1UL << PERF_BPIL_LINE_INFO;
        arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
        arrays |= 1UL << PERF_BPIL_MAP_IDS;

        info_linear = get_bpf_prog_info_linear(fd, arrays);
        if (IS_ERR_OR_NULL(info_linear)) {
                info_linear = NULL;
                pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
                return -1;
        }

        if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
                free(info_linear);
                pr_debug("%s: the kernel is too old, aborting\n", __func__);
                return -2;
        }

        info = &info_linear->info;
        if (!info->jited_ksyms) {
                free(info_linear);
                return -1;
        }

        /* number of ksyms, func_lengths, and tags should match */
        sub_prog_cnt = info->nr_jited_ksyms;
        if (sub_prog_cnt != info->nr_prog_tags ||
            sub_prog_cnt != info->nr_jited_func_lens) {
                free(info_linear);
                return -1;
        }

        /* check BTF func info support */
        if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
                /* btf func info number should be same as sub_prog_cnt */
                if (sub_prog_cnt != info->nr_func_info) {
                        pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
                        free(info_linear);
                        return -1;
                }
                btf = btf__load_from_kernel_by_id(info->btf_id);
                if (libbpf_get_error(btf)) {
                        pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
                        err = -1;
                        goto out;
                }
                perf_env__fetch_btf(env, info->btf_id, btf);
        }

        /* Synthesize PERF_RECORD_KSYMBOL */
        for (i = 0; i < sub_prog_cnt; i++) {
                __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
                __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
                int name_len;

                *ksymbol_event = (struct perf_record_ksymbol) {
                        .header = {
                                .type = PERF_RECORD_KSYMBOL,
                                .size = offsetof(struct perf_record_ksymbol, name),
                        },
                        .addr = prog_addrs[i],
                        .len = prog_lens[i],
                        .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
                        .flags = 0,
                };

                name_len = synthesize_bpf_prog_name(ksymbol_event->name,
                                                    KSYM_NAME_LEN, info, btf, i);
                ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
                                                         sizeof(u64));

                memset((void *)event + event->header.size, 0, machine->id_hdr_size);
                event->header.size += machine->id_hdr_size;
                err = perf_tool__process_synth_event(tool, event,
                                                     machine, process);
        }

        if (!opts->no_bpf_event) {
                /* Synthesize PERF_RECORD_BPF_EVENT */
                *bpf_event = (struct perf_record_bpf_event) {
                        .header = {
                                .type = PERF_RECORD_BPF_EVENT,
                                .size = sizeof(struct perf_record_bpf_event),
                        },
                        .type = PERF_BPF_EVENT_PROG_LOAD,
                        .flags = 0,
                        .id = info->id,
                };
                memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
                memset((void *)event + event->header.size, 0, machine->id_hdr_size);
                event->header.size += machine->id_hdr_size;

                /* save bpf_prog_info to env */
                info_node = malloc(sizeof(struct bpf_prog_info_node));
                if (!info_node) {
                        err = -1;
                        goto out;
                }

                info_node->info_linear = info_linear;
                info_node->metadata = NULL;
                if (!perf_env__insert_bpf_prog_info(env, info_node)) {
                        /*
                         * Insert failed, likely because of a duplicate event
                         * made by the sideband thread. Ignore synthesizing the
                         * metadata.
                         */
                        free(info_node);
                        goto out;
                }
                /* info_linear is now owned by info_node and shouldn't be freed below. */
                info_linear = NULL;

                /*
                 * process after saving bpf_prog_info to env, so that
                 * required information is ready for look up
                 */
                err = perf_tool__process_synth_event(tool, event,
                                                     machine, process);

                /* Synthesize PERF_RECORD_BPF_METADATA */
                metadata = bpf_metadata_create(info);
                if (metadata != NULL) {
                        err = synthesize_perf_record_bpf_metadata(metadata,
                                                                  tool, process,
                                                                  machine);
                        bpf_metadata_free(metadata);
                }
        }

out:
        free(info_linear);
        btf__free(btf);
        return err ? -1 : 0;
}

struct kallsyms_parse {
        union perf_event        *event;
        perf_event__handler_t    process;
        struct machine          *machine;
        const struct perf_tool  *tool;
};

static int
process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
{
        struct machine *machine = data->machine;
        union perf_event *event = data->event;
        struct perf_record_ksymbol *ksymbol;
        int len;

        ksymbol = &event->ksymbol;

        *ksymbol = (struct perf_record_ksymbol) {
                .header = {
                        .type = PERF_RECORD_KSYMBOL,
                        .size = offsetof(struct perf_record_ksymbol, name),
                },
                .addr      = addr,
                .len       = page_size,
                .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
                .flags     = 0,
        };

        len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
        ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
        memset((void *) event + event->header.size, 0, machine->id_hdr_size);
        event->header.size += machine->id_hdr_size;

        return perf_tool__process_synth_event(data->tool, event, machine,
                                              data->process);
}

static int
kallsyms_process_symbol(void *data, const char *_name,
                        char type __maybe_unused, u64 start)
{
        char disp[KSYM_NAME_LEN];
        const char *module;
        char *name;
        unsigned long id;
        int err = 0;

        module = strchr(_name, '\t');
        if (!module)
                return 0;

        /* We are going after [bpf] module ... */
        if (strcmp(module + 1, "[bpf]"))
                return 0;

        name = memdup(_name, (module - _name) + 1);
        if (!name)
                return -ENOMEM;

        name[module - _name] = 0;

        /* .. and only for trampolines and dispatchers */
        if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
            (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
                err = process_bpf_image(name, start, data);

        free(name);
        return err;
}

int perf_event__synthesize_bpf_events(struct perf_session *session,
                                      perf_event__handler_t process,
                                      struct machine *machine,
                                      struct record_opts *opts)
{
        const char *kallsyms_filename = "/proc/kallsyms";
        struct kallsyms_parse arg;
        union perf_event *event;
        __u32 id = 0;
        int err;
        int fd;

        if (opts->no_bpf_event)
                return 0;

        event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
        if (!event)
                return -1;

        /* Synthesize all the bpf programs in system. */
        while (true) {
                err = bpf_prog_get_next_id(id, &id);
                if (err) {
                        if (errno == ENOENT) {
                                err = 0;
                                break;
                        }
                        /* don't report error on old kernel or EPERM  */
                        err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
                        pr_debug("%s: can\'t get next program: %m%s\n",
                                __func__, errno == EINVAL ? " -- kernel too old?" : "");
                        break;
                }
                fd = bpf_prog_get_fd_by_id(id);
                if (fd < 0) {
                        pr_debug("%s: failed to get fd for prog_id %u\n",
                                 __func__, id);
                        continue;
                }

                err = perf_event__synthesize_one_bpf_prog(session, process,
                                                          machine, fd,
                                                          event, opts);
                close(fd);
                if (err) {
                        /* do not return error for old kernel */
                        if (err == -2)
                                err = 0;
                        break;
                }
        }

        /* Synthesize all the bpf images - trampolines/dispatchers. */
        if (symbol_conf.kallsyms_name != NULL)
                kallsyms_filename = symbol_conf.kallsyms_name;

        arg = (struct kallsyms_parse) {
                .event   = event,
                .process = process,
                .machine = machine,
                .tool    = session->tool,
        };

        if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol))
                pr_err("%s: failed to synthesize bpf images: %m\n", __func__);

        free(event);
        return err;
}

static int perf_env__add_bpf_info(struct perf_env *env, u32 id)
{
        struct bpf_prog_info_node *info_node;
        struct perf_bpil *info_linear;
        struct btf *btf = NULL;
        u64 arrays;
        u32 btf_id;
        int fd, err = 0;

        fd = bpf_prog_get_fd_by_id(id);
        if (fd < 0)
                return -EINVAL;

        arrays = 1UL << PERF_BPIL_JITED_KSYMS;
        arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
        arrays |= 1UL << PERF_BPIL_FUNC_INFO;
        arrays |= 1UL << PERF_BPIL_PROG_TAGS;
        arrays |= 1UL << PERF_BPIL_JITED_INSNS;
        arrays |= 1UL << PERF_BPIL_LINE_INFO;
        arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
        arrays |= 1UL << PERF_BPIL_MAP_IDS;

        info_linear = get_bpf_prog_info_linear(fd, arrays);
        if (IS_ERR_OR_NULL(info_linear)) {
                pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
                err = PTR_ERR(info_linear);
                goto out;
        }

        btf_id = info_linear->info.btf_id;

        info_node = malloc(sizeof(struct bpf_prog_info_node));
        if (info_node) {
                info_node->info_linear = info_linear;
                info_node->metadata = bpf_metadata_create(&info_linear->info);
                if (!perf_env__insert_bpf_prog_info(env, info_node)) {
                        pr_debug("%s: duplicate add bpf info request for id %u\n",
                                 __func__, btf_id);
                        free(info_linear);
                        free(info_node);
                        goto out;
                }
        } else {
                free(info_linear);
                err = -ENOMEM;
                goto out;
        }

        if (btf_id == 0)
                goto out;

        btf = btf__load_from_kernel_by_id(btf_id);
        if (!btf) {
                err = -errno;
                pr_debug("%s: failed to get BTF of id %u %d\n", __func__, btf_id, err);
        } else {
                perf_env__fetch_btf(env, btf_id, btf);
        }

out:
        btf__free(btf);
        close(fd);
        return err;
}

static int bpf_event__sb_cb(union perf_event *event, void *data)
{
        struct perf_env *env = data;
        int ret = 0;

        if (event->header.type != PERF_RECORD_BPF_EVENT)
                return -1;

        switch (event->bpf.type) {
        case PERF_BPF_EVENT_PROG_LOAD:
                ret = perf_env__add_bpf_info(env, event->bpf.id);

        case PERF_BPF_EVENT_PROG_UNLOAD:
                /*
                 * Do not free bpf_prog_info and btf of the program here,
                 * as annotation still need them. They will be freed at
                 * the end of the session.
                 */
                break;
        default:
                pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
                break;
        }

        return ret;
}

int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
{
        struct perf_event_attr attr = {
                .type             = PERF_TYPE_SOFTWARE,
                .config           = PERF_COUNT_SW_DUMMY,
                .sample_id_all    = 1,
                .watermark        = 1,
                .bpf_event        = 1,
                .size      = sizeof(attr), /* to capture ABI version */
        };

        /*
         * Older gcc versions don't support designated initializers, like above,
         * for unnamed union members, such as the following:
         */
        attr.wakeup_watermark = 1;

        return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
}

void __bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
                                      struct perf_env *env,
                                      FILE *fp)
{
        __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
        __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
        char name[KSYM_NAME_LEN];
        struct btf *btf = NULL;
        u32 sub_prog_cnt, i;

        sub_prog_cnt = info->nr_jited_ksyms;
        if (sub_prog_cnt != info->nr_prog_tags ||
            sub_prog_cnt != info->nr_jited_func_lens)
                return;

        if (info->btf_id) {
                struct btf_node *node;

                node = __perf_env__find_btf(env, info->btf_id);
                if (node)
                        btf = btf__new((__u8 *)(node->data),
                                       node->data_size);
        }

        if (sub_prog_cnt == 1) {
                synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
                fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
                        info->id, name, prog_addrs[0], prog_lens[0]);
                goto out;
        }

        fprintf(fp, "# bpf_prog_info %u:\n", info->id);
        for (i = 0; i < sub_prog_cnt; i++) {
                synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);

                fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
                        i, name, prog_addrs[i], prog_lens[i]);
        }
out:
        btf__free(btf);
}