// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022, Oracle and/or its affiliates. */
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>

char _license[] SEC("license") = "GPL";

unsigned long last_sym_value = 0;

static inline char to_lower(char c)
{
        if (c >= 'A' && c <= 'Z')
                c += ('a' - 'A');
        return c;
}

static inline char to_upper(char c)
{
        if (c >= 'a' && c <= 'z')
                c -= ('a' - 'A');
        return c;
}

/* Dump symbols with max size; the latter is calculated by caching symbol N value
 * and when iterating on symbol N+1, we can print max size of symbol N via
 * address of N+1 - address of N.
 */
SEC("iter/ksym")
int dump_ksym(struct bpf_iter__ksym *ctx)
{
        struct seq_file *seq = ctx->meta->seq;
        struct kallsym_iter *iter = ctx->ksym;
        __u32 seq_num = ctx->meta->seq_num;
        unsigned long value;
        char type;

        if (!iter)
                return 0;

        if (seq_num == 0) {
                BPF_SEQ_PRINTF(seq, "ADDR TYPE NAME MODULE_NAME KIND MAX_SIZE\n");
                return 0;
        }
        if (last_sym_value)
                BPF_SEQ_PRINTF(seq, "0x%x\n", iter->value - last_sym_value);
        else
                BPF_SEQ_PRINTF(seq, "\n");

        value = iter->show_value ? iter->value : 0;

        last_sym_value = value;

        type = iter->type;

        if (iter->module_name[0]) {
                type = iter->exported ? to_upper(type) : to_lower(type);
                BPF_SEQ_PRINTF(seq, "0x%llx %c %s [ %s ] ",
                               value, type, iter->name, iter->module_name);
        } else {
                BPF_SEQ_PRINTF(seq, "0x%llx %c %s ", value, type, iter->name);
        }
        if (!iter->pos_mod_end || iter->pos_mod_end > iter->pos)
                BPF_SEQ_PRINTF(seq, "MOD ");
        else if (!iter->pos_ftrace_mod_end || iter->pos_ftrace_mod_end > iter->pos)
                BPF_SEQ_PRINTF(seq, "FTRACE_MOD ");
        else if (!iter->pos_bpf_end || iter->pos_bpf_end > iter->pos)
                BPF_SEQ_PRINTF(seq, "BPF ");
        else
                BPF_SEQ_PRINTF(seq, "KPROBE ");
        return 0;
}