// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (c) 2018 Facebook */

#include <ctype.h>
#include <stdio.h> /* for (FILE *) used by json_writer */
#include <string.h>
#include <unistd.h>
#include <asm/byteorder.h>
#include <linux/bitops.h>
#include <linux/btf.h>
#include <linux/err.h>
#include <bpf/btf.h>
#include <bpf/bpf.h>

#include "json_writer.h"
#include "main.h"

#define BITS_PER_BYTE_MASK (BITS_PER_BYTE - 1)
#define BITS_PER_BYTE_MASKED(bits) ((bits) & BITS_PER_BYTE_MASK)
#define BITS_ROUNDDOWN_BYTES(bits) ((bits) >> 3)
#define BITS_ROUNDUP_BYTES(bits) \
        (BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))

static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
                              __u8 bit_offset, const void *data);

static int btf_dump_func(const struct btf *btf, char *func_sig,
                         const struct btf_type *func_proto,
                         const struct btf_type *func, int pos, int size);

static int dump_prog_id_as_func_ptr(const struct btf_dumper *d,
                                    const struct btf_type *func_proto,
                                    __u32 prog_id)
{
        const struct btf_type *func_type;
        int prog_fd = -1, func_sig_len;
        struct bpf_prog_info info = {};
        __u32 info_len = sizeof(info);
        const char *prog_name = NULL;
        struct btf *prog_btf = NULL;
        struct bpf_func_info finfo = {};
        __u32 finfo_rec_size;
        char prog_str[1024];
        int err;

        /* Get the ptr's func_proto */
        func_sig_len = btf_dump_func(d->btf, prog_str, func_proto, NULL, 0,
                                     sizeof(prog_str));
        if (func_sig_len == -1)
                return -1;

        if (!prog_id)
                goto print;

        /* Get the bpf_prog's name.  Obtain from func_info. */
        prog_fd = bpf_prog_get_fd_by_id(prog_id);
        if (prog_fd < 0)
                goto print;

        err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
        if (err)
                goto print;

        if (!info.btf_id || !info.nr_func_info)
                goto print;

        finfo_rec_size = info.func_info_rec_size;
        memset(&info, 0, sizeof(info));
        info.nr_func_info = 1;
        info.func_info_rec_size = finfo_rec_size;
        info.func_info = ptr_to_u64(&finfo);

        err = bpf_prog_get_info_by_fd(prog_fd, &info, &info_len);
        if (err)
                goto print;

        prog_btf = btf__load_from_kernel_by_id(info.btf_id);
        if (!prog_btf)
                goto print;
        func_type = btf__type_by_id(prog_btf, finfo.type_id);
        if (!func_type || !btf_is_func(func_type))
                goto print;

        prog_name = btf__name_by_offset(prog_btf, func_type->name_off);

print:
        if (!prog_id)
                snprintf(&prog_str[func_sig_len],
                         sizeof(prog_str) - func_sig_len, " 0");
        else if (prog_name)
                snprintf(&prog_str[func_sig_len],
                         sizeof(prog_str) - func_sig_len,
                         " %s/prog_id:%u", prog_name, prog_id);
        else
                snprintf(&prog_str[func_sig_len],
                         sizeof(prog_str) - func_sig_len,
                         " <unknown_prog_name>/prog_id:%u", prog_id);

        prog_str[sizeof(prog_str) - 1] = '\0';
        jsonw_string(d->jw, prog_str);
        btf__free(prog_btf);
        if (prog_fd >= 0)
                close(prog_fd);
        return 0;
}

static void btf_dumper_ptr(const struct btf_dumper *d,
                           const struct btf_type *t,
                           const void *data)
{
        unsigned long value = *(unsigned long *)data;
        const struct btf_type *ptr_type;
        __s32 ptr_type_id;

        if (!d->prog_id_as_func_ptr || value > UINT32_MAX)
                goto print_ptr_value;

        ptr_type_id = btf__resolve_type(d->btf, t->type);
        if (ptr_type_id < 0)
                goto print_ptr_value;
        ptr_type = btf__type_by_id(d->btf, ptr_type_id);
        if (!ptr_type || !btf_is_func_proto(ptr_type))
                goto print_ptr_value;

        if (!dump_prog_id_as_func_ptr(d, ptr_type, value))
                return;

print_ptr_value:
        if (d->is_plain_text)
                jsonw_printf(d->jw, "\"%p\"", (void *)value);
        else
                jsonw_printf(d->jw, "%lu", value);
}

static int btf_dumper_modifier(const struct btf_dumper *d, __u32 type_id,
                               __u8 bit_offset, const void *data)
{
        int actual_type_id;

        actual_type_id = btf__resolve_type(d->btf, type_id);
        if (actual_type_id < 0)
                return actual_type_id;

        return btf_dumper_do_type(d, actual_type_id, bit_offset, data);
}

static int btf_dumper_enum(const struct btf_dumper *d,
                            const struct btf_type *t,
                            const void *data)
{
        const struct btf_enum *enums = btf_enum(t);
        __s64 value;
        __u16 i;

        switch (t->size) {
        case 8:
                value = *(__s64 *)data;
                break;
        case 4:
                value = *(__s32 *)data;
                break;
        case 2:
                value = *(__s16 *)data;
                break;
        case 1:
                value = *(__s8 *)data;
                break;
        default:
                return -EINVAL;
        }

        for (i = 0; i < btf_vlen(t); i++) {
                if (value == enums[i].val) {
                        jsonw_string(d->jw,
                                     btf__name_by_offset(d->btf,
                                                         enums[i].name_off));
                        return 0;
                }
        }

        jsonw_int(d->jw, value);
        return 0;
}

static int btf_dumper_enum64(const struct btf_dumper *d,
                             const struct btf_type *t,
                             const void *data)
{
        const struct btf_enum64 *enums = btf_enum64(t);
        __u32 val_lo32, val_hi32;
        __u64 value;
        __u16 i;

        value = *(__u64 *)data;
        val_lo32 = (__u32)value;
        val_hi32 = value >> 32;

        for (i = 0; i < btf_vlen(t); i++) {
                if (val_lo32 == enums[i].val_lo32 && val_hi32 == enums[i].val_hi32) {
                        jsonw_string(d->jw,
                                     btf__name_by_offset(d->btf,
                                                         enums[i].name_off));
                        return 0;
                }
        }

        jsonw_int(d->jw, value);
        return 0;
}

static bool is_str_array(const struct btf *btf, const struct btf_array *arr,
                         const char *s)
{
        const struct btf_type *elem_type;
        const char *end_s;

        if (!arr->nelems)
                return false;

        elem_type = btf__type_by_id(btf, arr->type);
        /* Not skipping typedef.  typedef to char does not count as
         * a string now.
         */
        while (elem_type && btf_is_mod(elem_type))
                elem_type = btf__type_by_id(btf, elem_type->type);

        if (!elem_type || !btf_is_int(elem_type) || elem_type->size != 1)
                return false;

        if (btf_int_encoding(elem_type) != BTF_INT_CHAR &&
            strcmp("char", btf__name_by_offset(btf, elem_type->name_off)))
                return false;

        end_s = s + arr->nelems;
        while (s < end_s) {
                if (!*s)
                        return true;
                if (*s <= 0x1f || *s >= 0x7f)
                        return false;
                s++;
        }

        /* '\0' is not found */
        return false;
}

static int btf_dumper_array(const struct btf_dumper *d, __u32 type_id,
                            const void *data)
{
        const struct btf_type *t = btf__type_by_id(d->btf, type_id);
        struct btf_array *arr = (struct btf_array *)(t + 1);
        long long elem_size;
        int ret = 0;
        __u32 i;

        if (is_str_array(d->btf, arr, data)) {
                jsonw_string(d->jw, data);
                return 0;
        }

        elem_size = btf__resolve_size(d->btf, arr->type);
        if (elem_size < 0)
                return elem_size;

        jsonw_start_array(d->jw);
        for (i = 0; i < arr->nelems; i++) {
                ret = btf_dumper_do_type(d, arr->type, 0,
                                         data + i * elem_size);
                if (ret)
                        break;
        }

        jsonw_end_array(d->jw);
        return ret;
}

static void btf_int128_print(json_writer_t *jw, const void *data,
                             bool is_plain_text)
{
        /* data points to a __int128 number.
         * Suppose
         *     int128_num = *(__int128 *)data;
         * The below formulas shows what upper_num and lower_num represents:
         *     upper_num = int128_num >> 64;
         *     lower_num = int128_num & 0xffffffffFFFFFFFFULL;
         */
        __u64 upper_num, lower_num;

#ifdef __BIG_ENDIAN_BITFIELD
        upper_num = *(__u64 *)data;
        lower_num = *(__u64 *)(data + 8);
#else
        upper_num = *(__u64 *)(data + 8);
        lower_num = *(__u64 *)data;
#endif

        if (is_plain_text) {
                if (upper_num == 0)
                        jsonw_printf(jw, "0x%llx", lower_num);
                else
                        jsonw_printf(jw, "0x%llx%016llx", upper_num, lower_num);
        } else {
                if (upper_num == 0)
                        jsonw_printf(jw, "\"0x%llx\"", lower_num);
                else
                        jsonw_printf(jw, "\"0x%llx%016llx\"", upper_num, lower_num);
        }
}

static void btf_int128_shift(__u64 *print_num, __u16 left_shift_bits,
                             __u16 right_shift_bits)
{
        __u64 upper_num, lower_num;

#ifdef __BIG_ENDIAN_BITFIELD
        upper_num = print_num[0];
        lower_num = print_num[1];
#else
        upper_num = print_num[1];
        lower_num = print_num[0];
#endif

        /* shake out un-needed bits by shift/or operations */
        if (left_shift_bits >= 64) {
                upper_num = lower_num << (left_shift_bits - 64);
                lower_num = 0;
        } else {
                upper_num = (upper_num << left_shift_bits) |
                            (lower_num >> (64 - left_shift_bits));
                lower_num = lower_num << left_shift_bits;
        }

        if (right_shift_bits >= 64) {
                lower_num = upper_num >> (right_shift_bits - 64);
                upper_num = 0;
        } else {
                lower_num = (lower_num >> right_shift_bits) |
                            (upper_num << (64 - right_shift_bits));
                upper_num = upper_num >> right_shift_bits;
        }

#ifdef __BIG_ENDIAN_BITFIELD
        print_num[0] = upper_num;
        print_num[1] = lower_num;
#else
        print_num[0] = lower_num;
        print_num[1] = upper_num;
#endif
}

static void btf_dumper_bitfield(__u32 nr_bits, __u8 bit_offset,
                                const void *data, json_writer_t *jw,
                                bool is_plain_text)
{
        int left_shift_bits, right_shift_bits;
        __u64 print_num[2] = {};
        int bytes_to_copy;
        int bits_to_copy;

        bits_to_copy = bit_offset + nr_bits;
        bytes_to_copy = BITS_ROUNDUP_BYTES(bits_to_copy);

        memcpy(print_num, data, bytes_to_copy);
#if defined(__BIG_ENDIAN_BITFIELD)
        left_shift_bits = bit_offset;
#elif defined(__LITTLE_ENDIAN_BITFIELD)
        left_shift_bits = 128 - bits_to_copy;
#else
#error neither big nor little endian
#endif
        right_shift_bits = 128 - nr_bits;

        btf_int128_shift(print_num, left_shift_bits, right_shift_bits);
        btf_int128_print(jw, print_num, is_plain_text);
}


static void btf_dumper_int_bits(__u32 int_type, __u8 bit_offset,
                                const void *data, json_writer_t *jw,
                                bool is_plain_text)
{
        int nr_bits = BTF_INT_BITS(int_type);
        int total_bits_offset;

        /* bits_offset is at most 7.
         * BTF_INT_OFFSET() cannot exceed 128 bits.
         */
        total_bits_offset = bit_offset + BTF_INT_OFFSET(int_type);
        data += BITS_ROUNDDOWN_BYTES(total_bits_offset);
        bit_offset = BITS_PER_BYTE_MASKED(total_bits_offset);
        btf_dumper_bitfield(nr_bits, bit_offset, data, jw,
                            is_plain_text);
}

static int btf_dumper_int(const struct btf_type *t, __u8 bit_offset,
                          const void *data, json_writer_t *jw,
                          bool is_plain_text)
{
        __u32 *int_type;
        __u32 nr_bits;

        int_type = (__u32 *)(t + 1);
        nr_bits = BTF_INT_BITS(*int_type);
        /* if this is bit field */
        if (bit_offset || BTF_INT_OFFSET(*int_type) ||
            BITS_PER_BYTE_MASKED(nr_bits)) {
                btf_dumper_int_bits(*int_type, bit_offset, data, jw,
                                    is_plain_text);
                return 0;
        }

        if (nr_bits == 128) {
                btf_int128_print(jw, data, is_plain_text);
                return 0;
        }

        switch (BTF_INT_ENCODING(*int_type)) {
        case 0:
                if (BTF_INT_BITS(*int_type) == 64)
                        jsonw_printf(jw, "%llu", *(__u64 *)data);
                else if (BTF_INT_BITS(*int_type) == 32)
                        jsonw_printf(jw, "%u", *(__u32 *)data);
                else if (BTF_INT_BITS(*int_type) == 16)
                        jsonw_printf(jw, "%hu", *(__u16 *)data);
                else if (BTF_INT_BITS(*int_type) == 8)
                        jsonw_printf(jw, "%hhu", *(__u8 *)data);
                else
                        btf_dumper_int_bits(*int_type, bit_offset, data, jw,
                                            is_plain_text);
                break;
        case BTF_INT_SIGNED:
                if (BTF_INT_BITS(*int_type) == 64)
                        jsonw_printf(jw, "%lld", *(long long *)data);
                else if (BTF_INT_BITS(*int_type) == 32)
                        jsonw_printf(jw, "%d", *(int *)data);
                else if (BTF_INT_BITS(*int_type) == 16)
                        jsonw_printf(jw, "%hd", *(short *)data);
                else if (BTF_INT_BITS(*int_type) == 8)
                        jsonw_printf(jw, "%hhd", *(char *)data);
                else
                        btf_dumper_int_bits(*int_type, bit_offset, data, jw,
                                            is_plain_text);
                break;
        case BTF_INT_CHAR:
                if (isprint(*(char *)data))
                        jsonw_printf(jw, "\"%c\"", *(char *)data);
                else
                        if (is_plain_text)
                                jsonw_printf(jw, "0x%hhx", *(char *)data);
                        else
                                jsonw_printf(jw, "\"\\u00%02hhx\"",
                                             *(char *)data);
                break;
        case BTF_INT_BOOL:
                jsonw_bool(jw, *(bool *)data);
                break;
        default:
                /* shouldn't happen */
                return -EINVAL;
        }

        return 0;
}

static int btf_dumper_struct(const struct btf_dumper *d, __u32 type_id,
                             const void *data)
{
        const struct btf_type *t;
        struct btf_member *m;
        const void *data_off;
        int kind_flag;
        int ret = 0;
        int i, vlen;

        t = btf__type_by_id(d->btf, type_id);
        if (!t)
                return -EINVAL;

        kind_flag = BTF_INFO_KFLAG(t->info);
        vlen = BTF_INFO_VLEN(t->info);
        jsonw_start_object(d->jw);
        m = (struct btf_member *)(t + 1);

        for (i = 0; i < vlen; i++) {
                __u32 bit_offset = m[i].offset;
                __u32 bitfield_size = 0;

                if (kind_flag) {
                        bitfield_size = BTF_MEMBER_BITFIELD_SIZE(bit_offset);
                        bit_offset = BTF_MEMBER_BIT_OFFSET(bit_offset);
                }

                jsonw_name(d->jw, btf__name_by_offset(d->btf, m[i].name_off));
                data_off = data + BITS_ROUNDDOWN_BYTES(bit_offset);
                if (bitfield_size) {
                        btf_dumper_bitfield(bitfield_size,
                                            BITS_PER_BYTE_MASKED(bit_offset),
                                            data_off, d->jw, d->is_plain_text);
                } else {
                        ret = btf_dumper_do_type(d, m[i].type,
                                                 BITS_PER_BYTE_MASKED(bit_offset),
                                                 data_off);
                        if (ret)
                                break;
                }
        }

        jsonw_end_object(d->jw);

        return ret;
}

static int btf_dumper_var(const struct btf_dumper *d, __u32 type_id,
                          __u8 bit_offset, const void *data)
{
        const struct btf_type *t = btf__type_by_id(d->btf, type_id);
        int ret;

        jsonw_start_object(d->jw);
        jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
        ret = btf_dumper_do_type(d, t->type, bit_offset, data);
        jsonw_end_object(d->jw);

        return ret;
}

static int btf_dumper_datasec(const struct btf_dumper *d, __u32 type_id,
                              const void *data)
{
        struct btf_var_secinfo *vsi;
        const struct btf_type *t;
        int ret = 0, i, vlen;

        t = btf__type_by_id(d->btf, type_id);
        if (!t)
                return -EINVAL;

        vlen = BTF_INFO_VLEN(t->info);
        vsi = (struct btf_var_secinfo *)(t + 1);

        jsonw_start_object(d->jw);
        jsonw_name(d->jw, btf__name_by_offset(d->btf, t->name_off));
        jsonw_start_array(d->jw);
        for (i = 0; i < vlen; i++) {
                ret = btf_dumper_do_type(d, vsi[i].type, 0, data + vsi[i].offset);
                if (ret)
                        break;
        }
        jsonw_end_array(d->jw);
        jsonw_end_object(d->jw);

        return ret;
}

static int btf_dumper_do_type(const struct btf_dumper *d, __u32 type_id,
                              __u8 bit_offset, const void *data)
{
        const struct btf_type *t = btf__type_by_id(d->btf, type_id);

        switch (BTF_INFO_KIND(t->info)) {
        case BTF_KIND_INT:
                return btf_dumper_int(t, bit_offset, data, d->jw,
                                     d->is_plain_text);
        case BTF_KIND_STRUCT:
        case BTF_KIND_UNION:
                return btf_dumper_struct(d, type_id, data);
        case BTF_KIND_ARRAY:
                return btf_dumper_array(d, type_id, data);
        case BTF_KIND_ENUM:
                return btf_dumper_enum(d, t, data);
        case BTF_KIND_ENUM64:
                return btf_dumper_enum64(d, t, data);
        case BTF_KIND_PTR:
                btf_dumper_ptr(d, t, data);
                return 0;
        case BTF_KIND_UNKN:
                jsonw_printf(d->jw, "(unknown)");
                return 0;
        case BTF_KIND_FWD:
                /* map key or value can't be forward */
                jsonw_printf(d->jw, "(fwd-kind-invalid)");
                return -EINVAL;
        case BTF_KIND_TYPEDEF:
        case BTF_KIND_VOLATILE:
        case BTF_KIND_CONST:
        case BTF_KIND_RESTRICT:
                return btf_dumper_modifier(d, type_id, bit_offset, data);
        case BTF_KIND_VAR:
                return btf_dumper_var(d, type_id, bit_offset, data);
        case BTF_KIND_DATASEC:
                return btf_dumper_datasec(d, type_id, data);
        default:
                jsonw_printf(d->jw, "(unsupported-kind)");
                return -EINVAL;
        }
}

int btf_dumper_type(const struct btf_dumper *d, __u32 type_id,
                    const void *data)
{
        return btf_dumper_do_type(d, type_id, 0, data);
}

#define BTF_PRINT_ARG(...)                                              \
        do {                                                            \
                pos += snprintf(func_sig + pos, size - pos,             \
                                __VA_ARGS__);                           \
                if (pos >= size)                                        \
                        return -1;                                      \
        } while (0)
#define BTF_PRINT_TYPE(type)                                    \
        do {                                                            \
                pos = __btf_dumper_type_only(btf, type, func_sig,       \
                                             pos, size);                \
                if (pos == -1)                                          \
                        return -1;                                      \
        } while (0)

static int __btf_dumper_type_only(const struct btf *btf, __u32 type_id,
                                  char *func_sig, int pos, int size)
{
        const struct btf_type *proto_type;
        const struct btf_array *array;
        const struct btf_var *var;
        const struct btf_type *t;

        if (!type_id) {
                BTF_PRINT_ARG("void ");
                return pos;
        }

        t = btf__type_by_id(btf, type_id);

        switch (BTF_INFO_KIND(t->info)) {
        case BTF_KIND_INT:
        case BTF_KIND_TYPEDEF:
        case BTF_KIND_FLOAT:
                BTF_PRINT_ARG("%s ", btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_STRUCT:
                BTF_PRINT_ARG("struct %s ",
                              btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_UNION:
                BTF_PRINT_ARG("union %s ",
                              btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_ENUM:
        case BTF_KIND_ENUM64:
                BTF_PRINT_ARG("enum %s ",
                              btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_ARRAY:
                array = (struct btf_array *)(t + 1);
                BTF_PRINT_TYPE(array->type);
                BTF_PRINT_ARG("[%u]", array->nelems);
                break;
        case BTF_KIND_PTR:
                BTF_PRINT_TYPE(t->type);
                BTF_PRINT_ARG("* ");
                break;
        case BTF_KIND_FWD:
                BTF_PRINT_ARG("%s %s ",
                              BTF_INFO_KFLAG(t->info) ? "union" : "struct",
                              btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_VOLATILE:
                BTF_PRINT_ARG("volatile ");
                BTF_PRINT_TYPE(t->type);
                break;
        case BTF_KIND_CONST:
                BTF_PRINT_ARG("const ");
                BTF_PRINT_TYPE(t->type);
                break;
        case BTF_KIND_RESTRICT:
                BTF_PRINT_ARG("restrict ");
                BTF_PRINT_TYPE(t->type);
                break;
        case BTF_KIND_FUNC_PROTO:
                pos = btf_dump_func(btf, func_sig, t, NULL, pos, size);
                if (pos == -1)
                        return -1;
                break;
        case BTF_KIND_FUNC:
                proto_type = btf__type_by_id(btf, t->type);
                pos = btf_dump_func(btf, func_sig, proto_type, t, pos, size);
                if (pos == -1)
                        return -1;
                break;
        case BTF_KIND_VAR:
                var = (struct btf_var *)(t + 1);
                if (var->linkage == BTF_VAR_STATIC)
                        BTF_PRINT_ARG("static ");
                BTF_PRINT_TYPE(t->type);
                BTF_PRINT_ARG(" %s",
                              btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_DATASEC:
                BTF_PRINT_ARG("section (\"%s\") ",
                              btf__name_by_offset(btf, t->name_off));
                break;
        case BTF_KIND_UNKN:
        default:
                return -1;
        }

        return pos;
}

static int btf_dump_func(const struct btf *btf, char *func_sig,
                         const struct btf_type *func_proto,
                         const struct btf_type *func, int pos, int size)
{
        int i, vlen;

        BTF_PRINT_TYPE(func_proto->type);
        if (func)
                BTF_PRINT_ARG("%s(", btf__name_by_offset(btf, func->name_off));
        else
                BTF_PRINT_ARG("(");
        vlen = BTF_INFO_VLEN(func_proto->info);
        for (i = 0; i < vlen; i++) {
                struct btf_param *arg = &((struct btf_param *)(func_proto + 1))[i];

                if (i)
                        BTF_PRINT_ARG(", ");
                if (arg->type) {
                        BTF_PRINT_TYPE(arg->type);
                        if (arg->name_off)
                                BTF_PRINT_ARG("%s",
                                              btf__name_by_offset(btf, arg->name_off));
                        else if (pos && func_sig[pos - 1] == ' ')
                                /* Remove unnecessary space for
                                 * FUNC_PROTO that does not have
                                 * arg->name_off
                                 */
                                func_sig[--pos] = '\0';
                } else {
                        BTF_PRINT_ARG("...");
                }
        }
        BTF_PRINT_ARG(")");

        return pos;
}

void btf_dumper_type_only(const struct btf *btf, __u32 type_id, char *func_sig,
                          int size)
{
        int err;

        func_sig[0] = '\0';
        if (!btf)
                return;

        err = __btf_dumper_type_only(btf, type_id, func_sig, 0, size);
        if (err < 0)
                func_sig[0] = '\0';
}

static const char *ltrim(const char *s)
{
        while (isspace(*s))
                s++;

        return s;
}

void btf_dump_linfo_plain(const struct btf *btf,
                          const struct bpf_line_info *linfo,
                          const char *prefix, bool linum)
{
        const char *line = btf__name_by_offset(btf, linfo->line_off);

        if (!line)
                return;
        line = ltrim(line);

        if (!prefix)
                prefix = "";

        if (linum) {
                const char *file = btf__name_by_offset(btf, linfo->file_name_off);

                /* More forgiving on file because linum option is
                 * expected to provide more info than the already
                 * available src line.
                 */
                if (!file)
                        file = "";

                printf("%s%s [file:%s line_num:%u line_col:%u]\n",
                       prefix, line, file,
                       BPF_LINE_INFO_LINE_NUM(linfo->line_col),
                       BPF_LINE_INFO_LINE_COL(linfo->line_col));
        } else {
                printf("%s%s\n", prefix, line);
        }
}

void btf_dump_linfo_json(const struct btf *btf,
                         const struct bpf_line_info *linfo, bool linum)
{
        const char *line = btf__name_by_offset(btf, linfo->line_off);

        if (line)
                jsonw_string_field(json_wtr, "src", ltrim(line));

        if (linum) {
                const char *file = btf__name_by_offset(btf, linfo->file_name_off);

                if (file)
                        jsonw_string_field(json_wtr, "file", file);

                if (BPF_LINE_INFO_LINE_NUM(linfo->line_col))
                        jsonw_int_field(json_wtr, "line_num",
                                        BPF_LINE_INFO_LINE_NUM(linfo->line_col));

                if (BPF_LINE_INFO_LINE_COL(linfo->line_col))
                        jsonw_int_field(json_wtr, "line_col",
                                        BPF_LINE_INFO_LINE_COL(linfo->line_col));
        }
}

static void dotlabel_puts(const char *s)
{
        for (; *s; ++s) {
                switch (*s) {
                case '\\':
                case '"':
                case '{':
                case '}':
                case '<':
                case '>':
                case '|':
                case ' ':
                        putchar('\\');
                        fallthrough;
                default:
                        putchar(*s);
                }
        }
}

static const char *shorten_path(const char *path)
{
        const unsigned int MAX_PATH_LEN = 32;
        size_t len = strlen(path);
        const char *shortpath;

        if (len <= MAX_PATH_LEN)
                return path;

        /* Search for last '/' under the MAX_PATH_LEN limit */
        shortpath = strchr(path + len - MAX_PATH_LEN, '/');
        if (shortpath) {
                if (shortpath < path + strlen("..."))
                        /* We removed a very short prefix, e.g. "/w", and we'll
                         * make the path longer by prefixing with the ellipsis.
                         * Not worth it, keep initial path.
                         */
                        return path;
                return shortpath;
        }

        /* File base name length is > MAX_PATH_LEN, search for last '/' */
                        shortpath = strrchr(path, '/');
        if (shortpath)
                return shortpath;

        return path;
}

void btf_dump_linfo_dotlabel(const struct btf *btf,
                             const struct bpf_line_info *linfo, bool linum)
{
        const char *line = btf__name_by_offset(btf, linfo->line_off);

        if (!line || !strlen(line))
                return;
        line = ltrim(line);

        if (linum) {
                const char *file = btf__name_by_offset(btf, linfo->file_name_off);
                const char *shortfile;

                /* More forgiving on file because linum option is
                 * expected to provide more info than the already
                 * available src line.
                 */
                if (!file)
                        shortfile = "";
                else
                        shortfile = shorten_path(file);

                printf("; [%s", shortfile > file ? "..." : "");
                dotlabel_puts(shortfile);
                printf(" line:%u col:%u]\\l\\\n",
                       BPF_LINE_INFO_LINE_NUM(linfo->line_col),
                       BPF_LINE_INFO_LINE_COL(linfo->line_col));
        }

        printf("; ");
        dotlabel_puts(line);
        printf("\\l\\\n");
}