// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2026 Xiaomi */

#include <test_progs.h>
#include <bpf/btf.h>
#include "btf_helpers.h"

static void permute_base_check(struct btf *btf)
{
        VALIDATE_RAW_BTF(
                btf,
                "[1] STRUCT 's2' size=4 vlen=1\n"
                "\t'm' type_id=4 bits_offset=0",
                "[2] FUNC 'f' type_id=6 linkage=static",
                "[3] PTR '(anon)' type_id=4",
                "[4] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[5] STRUCT 's1' size=4 vlen=1\n"
                "\t'm' type_id=4 bits_offset=0",
                "[6] FUNC_PROTO '(anon)' ret_type_id=4 vlen=1\n"
                "\t'p' type_id=3");
}

/* Ensure btf__permute works as expected in the base-BTF scenario */
static void test_permute_base(void)
{
        struct btf *btf;
        __u32 permute_ids[7];
        int err;

        btf = btf__new_empty();
        if (!ASSERT_OK_PTR(btf, "empty_main_btf"))
                return;

        btf__add_int(btf, "int", 4, BTF_INT_SIGNED);    /* [1] int */
        btf__add_ptr(btf, 1);                           /* [2] ptr to int */
        btf__add_struct(btf, "s1", 4);                  /* [3] struct s1 { */
        btf__add_field(btf, "m", 1, 0, 0);              /*       int m; */
                                                        /* } */
        btf__add_struct(btf, "s2", 4);                  /* [4] struct s2 { */
        btf__add_field(btf, "m", 1, 0, 0);              /*       int m; */
                                                        /* } */
        btf__add_func_proto(btf, 1);                    /* [5] int (*)(int *p); */
        btf__add_func_param(btf, "p", 2);
        btf__add_func(btf, "f", BTF_FUNC_STATIC, 5);    /* [6] int f(int *p); */

        VALIDATE_RAW_BTF(
                btf,
                "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[2] PTR '(anon)' type_id=1",
                "[3] STRUCT 's1' size=4 vlen=1\n"
                "\t'm' type_id=1 bits_offset=0",
                "[4] STRUCT 's2' size=4 vlen=1\n"
                "\t'm' type_id=1 bits_offset=0",
                "[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
                "\t'p' type_id=2",
                "[6] FUNC 'f' type_id=5 linkage=static");

        permute_ids[0] = 0; /* [0] -> [0] */
        permute_ids[1] = 4; /* [1] -> [4] */
        permute_ids[2] = 3; /* [2] -> [3] */
        permute_ids[3] = 5; /* [3] -> [5] */
        permute_ids[4] = 1; /* [4] -> [1] */
        permute_ids[5] = 6; /* [5] -> [6] */
        permute_ids[6] = 2; /* [6] -> [2] */
        err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_OK(err, "btf__permute_base"))
                goto done;
        permute_base_check(btf);

        /* ids[0] must be 0 for base BTF */
        permute_ids[0] = 4; /* [0] -> [0] */
        permute_ids[1] = 0; /* [1] -> [4] */
        permute_ids[2] = 3; /* [2] -> [3] */
        permute_ids[3] = 5; /* [3] -> [5] */
        permute_ids[4] = 1; /* [4] -> [1] */
        permute_ids[5] = 6; /* [5] -> [6] */
        permute_ids[6] = 2; /* [6] -> [2] */
        err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_ERR(err, "btf__permute_base"))
                goto done;
        /* BTF is not modified */
        permute_base_check(btf);

        /* id_map_cnt is invalid */
        permute_ids[0] = 0; /* [0] -> [0] */
        permute_ids[1] = 4; /* [1] -> [4] */
        permute_ids[2] = 3; /* [2] -> [3] */
        permute_ids[3] = 5; /* [3] -> [5] */
        permute_ids[4] = 1; /* [4] -> [1] */
        permute_ids[5] = 6; /* [5] -> [6] */
        permute_ids[6] = 2; /* [6] -> [2] */
        err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids) - 1, NULL);
        if (!ASSERT_ERR(err, "btf__permute_base"))
                goto done;
        /* BTF is not modified */
        permute_base_check(btf);

        /* Multiple types can not be mapped to the same ID */
        permute_ids[0] = 0;
        permute_ids[1] = 4;
        permute_ids[2] = 4;
        permute_ids[3] = 5;
        permute_ids[4] = 1;
        permute_ids[5] = 6;
        permute_ids[6] = 2;
        err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_ERR(err, "btf__permute_base"))
                goto done;
        /* BTF is not modified */
        permute_base_check(btf);

        /* Type ID must be valid */
        permute_ids[0] = 0;
        permute_ids[1] = 4;
        permute_ids[2] = 3;
        permute_ids[3] = 5;
        permute_ids[4] = 1;
        permute_ids[5] = 7;
        permute_ids[6] = 2;
        err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_ERR(err, "btf__permute_base"))
                goto done;
        /* BTF is not modified */
        permute_base_check(btf);

done:
        btf__free(btf);
}

static void permute_split_check(struct btf *btf)
{
        VALIDATE_RAW_BTF(
                btf,
                "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[2] PTR '(anon)' type_id=1",
                "[3] STRUCT 's2' size=4 vlen=1\n"
                "\t'm' type_id=1 bits_offset=0",
                "[4] FUNC 'f' type_id=5 linkage=static",
                "[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
                "\t'p' type_id=2",
                "[6] STRUCT 's1' size=4 vlen=1\n"
                "\t'm' type_id=1 bits_offset=0");
}

/* Ensure btf__permute works as expected in the split-BTF scenario */
static void test_permute_split(void)
{
        struct btf *split_btf = NULL, *base_btf = NULL;
        __u32 permute_ids[4];
        int err, start_id;

        base_btf = btf__new_empty();
        if (!ASSERT_OK_PTR(base_btf, "empty_main_btf"))
                return;

        btf__add_int(base_btf, "int", 4, BTF_INT_SIGNED);       /* [1] int */
        btf__add_ptr(base_btf, 1);                              /* [2] ptr to int */
        VALIDATE_RAW_BTF(
                base_btf,
                "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[2] PTR '(anon)' type_id=1");
        split_btf = btf__new_empty_split(base_btf);
        if (!ASSERT_OK_PTR(split_btf, "empty_split_btf"))
                goto cleanup;
        btf__add_struct(split_btf, "s1", 4);                    /* [3] struct s1 { */
        btf__add_field(split_btf, "m", 1, 0, 0);                /*   int m; */
                                                                /* } */
        btf__add_struct(split_btf, "s2", 4);                    /* [4] struct s2 { */
        btf__add_field(split_btf, "m", 1, 0, 0);                /*   int m; */
                                                                /* } */
        btf__add_func_proto(split_btf, 1);                      /* [5] int (*)(int p); */
        btf__add_func_param(split_btf, "p", 2);
        btf__add_func(split_btf, "f", BTF_FUNC_STATIC, 5);      /* [6] int f(int *p); */

        VALIDATE_RAW_BTF(
                split_btf,
                "[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
                "[2] PTR '(anon)' type_id=1",
                "[3] STRUCT 's1' size=4 vlen=1\n"
                "\t'm' type_id=1 bits_offset=0",
                "[4] STRUCT 's2' size=4 vlen=1\n"
                "\t'm' type_id=1 bits_offset=0",
                "[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
                "\t'p' type_id=2",
                "[6] FUNC 'f' type_id=5 linkage=static");

        start_id = btf__type_cnt(base_btf);
        permute_ids[3 - start_id] = 6; /* [3] -> [6] */
        permute_ids[4 - start_id] = 3; /* [4] -> [3] */
        permute_ids[5 - start_id] = 5; /* [5] -> [5] */
        permute_ids[6 - start_id] = 4; /* [6] -> [4] */
        err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_OK(err, "btf__permute_split"))
                goto cleanup;
        permute_split_check(split_btf);

        /*
         * For split BTF, id_map_cnt must equal to the number of types
         * added on top of base BTF
         */
        permute_ids[3 - start_id] = 4;
        permute_ids[4 - start_id] = 3;
        permute_ids[5 - start_id] = 5;
        permute_ids[6 - start_id] = 6;
        err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids) - 1, NULL);
        if (!ASSERT_ERR(err, "btf__permute_split"))
                goto cleanup;
        /* BTF is not modified */
        permute_split_check(split_btf);

        /* Multiple types can not be mapped to the same ID */
        permute_ids[3 - start_id] = 4;
        permute_ids[4 - start_id] = 3;
        permute_ids[5 - start_id] = 3;
        permute_ids[6 - start_id] = 6;
        err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_ERR(err, "btf__permute_split"))
                goto cleanup;
        /* BTF is not modified */
        permute_split_check(split_btf);

        /* Can not map to base ID */
        permute_ids[3 - start_id] = 4;
        permute_ids[4 - start_id] = 2;
        permute_ids[5 - start_id] = 5;
        permute_ids[6 - start_id] = 6;
        err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
        if (!ASSERT_ERR(err, "btf__permute_split"))
                goto cleanup;
        /* BTF is not modified */
        permute_split_check(split_btf);

cleanup:
        btf__free(split_btf);
        btf__free(base_btf);
}

void test_btf_permute(void)
{
        if (test__start_subtest("permute_base"))
                test_permute_base();
        if (test__start_subtest("permute_split"))
                test_permute_split();
}