// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stdlib.h>
#include <bpf/bpf.h>
#include <bpf/btf.h>
#include <bpf/libbpf.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <linux/string.h>
#include <internal/lib.h>
#include <symbol/kallsyms.h>
#include "bpf-event.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"

struct btf * __weak btf__load_from_kernel_by_id(__u32 id)
{
       struct btf *btf;
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
       int err = btf__get_from_id(id, &btf);
#pragma GCC diagnostic pop

       return err ? ERR_PTR(err) : btf;
}

#define ptr_to_u64(ptr)    ((__u64)(unsigned long)(ptr))

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_linear *info_linear;
        struct bpf_prog_info_node *info_node;
        struct perf_env *env = machine->env;
        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->kmaps, addr);

                if (map) {
                        map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
                        map->dso->bpf_prog.id = id;
                        map->dso->bpf_prog.sub_id = i;
                        map->dso->bpf_prog.env = env;
                }
        }
        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__get_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);

        perf_env__insert_btf(env, node);
        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;
}

/*
 * 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;
        struct bpf_prog_info_linear *info_linear;
        struct perf_tool *tool = session->tool;
        struct bpf_prog_info_node *info_node;
        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 = session->data ? &session->header.env : &perf_env;

        arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
        arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
        arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
        arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
        arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
        arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
        arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

        info_linear = bpf_program__get_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;
                perf_env__insert_bpf_prog_info(env, info_node);
                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);
        }

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;
        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];
        char *module, *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;

        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;
                        }
                        pr_debug("%s: can't get next program: %s%s\n",
                                 __func__, strerror(errno),
                                 errno == EINVAL ? " -- kernel too old?" : "");
                        /* don't report error on old kernel or EPERM  */
                        err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
                        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: %s\n",
                       __func__, strerror(errno));
        }

        free(event);
        return err;
}

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

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

        arrays = 1UL << BPF_PROG_INFO_JITED_KSYMS;
        arrays |= 1UL << BPF_PROG_INFO_JITED_FUNC_LENS;
        arrays |= 1UL << BPF_PROG_INFO_FUNC_INFO;
        arrays |= 1UL << BPF_PROG_INFO_PROG_TAGS;
        arrays |= 1UL << BPF_PROG_INFO_JITED_INSNS;
        arrays |= 1UL << BPF_PROG_INFO_LINE_INFO;
        arrays |= 1UL << BPF_PROG_INFO_JITED_LINE_INFO;

        info_linear = bpf_program__get_prog_info_linear(fd, arrays);
        if (IS_ERR_OR_NULL(info_linear)) {
                pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
                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;
                perf_env__insert_bpf_prog_info(env, info_node);
        } else
                free(info_linear);

        if (btf_id == 0)
                goto out;

        btf = btf__load_from_kernel_by_id(btf_id);
        if (libbpf_get_error(btf)) {
                pr_debug("%s: failed to get BTF of id %u, aborting\n",
                         __func__, btf_id);
                goto out;
        }
        perf_env__fetch_btf(env, btf_id, btf);

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

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

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

        switch (event->bpf.type) {
        case PERF_BPF_EVENT_PROG_LOAD:
                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 0;
}

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]);
                return;
        }

        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]);
        }
}