// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
#include <test_progs.h>
#include <bpf/btf.h>

static char *dump_buf;
static size_t dump_buf_sz;
static FILE *dump_buf_file;

static void btf_dump_printf(void *ctx, const char *fmt, va_list args)
{
        vfprintf(ctx, fmt, args);
}

/* Write raw BTF to file, return number of bytes written or negative errno */
static ssize_t btf_raw_write(struct btf *btf, char *file)
{
        ssize_t written = 0;
        const void *data;
        __u32 size = 0;
        int fd, ret;

        fd = mkstemp(file);
        if (!ASSERT_GE(fd, 0, "create_file"))
                return -errno;

        data = btf__raw_data(btf, &size);
        if (!ASSERT_OK_PTR(data, "btf__raw_data")) {
                close(fd);
                return -EINVAL;
        }
        while (written < size) {
                ret = write(fd, data + written, size - written);
                if (!ASSERT_GE(ret, 0, "write succeeded")) {
                        close(fd);
                        return -errno;
                }
                written += ret;
        }
        close(fd);
        return written;
}

static void __test_btf_split(bool multi)
{
        char multisplit_btf_file[] = "/tmp/test_btf_multisplit.XXXXXX";
        char split_btf_file[] = "/tmp/test_btf_split.XXXXXX";
        char base_btf_file[] = "/tmp/test_btf_base.XXXXXX";
        ssize_t multisplit_btf_sz = 0, split_btf_sz = 0, base_btf_sz = 0;
        struct btf_dump *d = NULL;
        const struct btf_type *t, *ot;
        struct btf *btf1 = NULL, *btf2 = NULL, *btf3 = NULL;
        struct btf *btf4 = NULL, *btf5 = NULL, *btf6 = NULL;
        int str_off, i, err;

        btf1 = btf__new_empty();
        if (!ASSERT_OK_PTR(btf1, "empty_main_btf"))
                return;

        btf__set_pointer_size(btf1, 8); /* enforce 64-bit arch */

        btf__add_int(btf1, "int", 4, BTF_INT_SIGNED);   /* [1] int */
        btf__add_ptr(btf1, 1);                          /* [2] ptr to int */

        btf__add_struct(btf1, "s1", 4);                 /* [3] struct s1 { */
        btf__add_field(btf1, "f1", 1, 0, 0);            /*      int f1; */
                                                        /* } */

        btf2 = btf__new_empty_split(btf1);
        if (!ASSERT_OK_PTR(btf2, "empty_split_btf"))
                goto cleanup;

        /* pointer size should be "inherited" from main BTF */
        ASSERT_EQ(btf__pointer_size(btf2), 8, "inherit_ptr_sz");

        str_off = btf__find_str(btf2, "int");
        ASSERT_NEQ(str_off, -ENOENT, "str_int_missing");

        t = btf__type_by_id(btf2, 1);
        if (!ASSERT_OK_PTR(t, "int_type"))
                goto cleanup;
        ASSERT_EQ(btf_is_int(t), true, "int_kind");
        ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "int", "int_name");

        btf__add_struct(btf2, "s2", 16);                /* [4] struct s2 {      */
        btf__add_field(btf2, "f1", 3, 0, 0);            /*      struct s1 f1;   */
        btf__add_field(btf2, "f2", 1, 32, 0);           /*      int f2;         */
        btf__add_field(btf2, "f3", 2, 64, 0);           /*      int *f3;        */
                                                        /* } */

        t = btf__type_by_id(btf1, 4);
        ASSERT_NULL(t, "split_type_in_main");

        t = btf__type_by_id(btf2, 4);
        if (!ASSERT_OK_PTR(t, "split_struct_type"))
                goto cleanup;
        ASSERT_EQ(btf_is_struct(t), true, "split_struct_kind");
        ASSERT_EQ(btf_vlen(t), 3, "split_struct_vlen");
        ASSERT_STREQ(btf__str_by_offset(btf2, t->name_off), "s2", "split_struct_name");

        if (multi) {
                btf3 = btf__new_empty_split(btf2);
                if (!ASSERT_OK_PTR(btf3, "multi_split_btf"))
                        goto cleanup;
        } else {
                btf3 = btf2;
        }

        btf__add_union(btf3, "u1", 16);                 /* [5] union u1 {       */
        btf__add_field(btf3, "f1", 4, 0, 0);            /*      struct s2 f1;   */
        btf__add_field(btf3, "uf2", 1, 0, 0);           /*      int f2;         */
                                                        /* } */

        if (multi) {
                t = btf__type_by_id(btf2, 5);
                ASSERT_NULL(t, "multisplit_type_in_first_split");
        }

        t = btf__type_by_id(btf3, 5);
        if (!ASSERT_OK_PTR(t, "split_union_type"))
                goto cleanup;
        ASSERT_EQ(btf_is_union(t), true, "split_union_kind");
        ASSERT_EQ(btf_vlen(t), 2, "split_union_vlen");
        ASSERT_STREQ(btf__str_by_offset(btf3, t->name_off), "u1", "split_union_name");
        ASSERT_EQ(btf__type_cnt(btf3), 6, "split_type_cnt");

        t = btf__type_by_id(btf3, 1);
        if (!ASSERT_OK_PTR(t, "split_base_type"))
                goto cleanup;
        ASSERT_EQ(btf_is_int(t), true, "split_base_int");
        ASSERT_STREQ(btf__str_by_offset(btf3, t->name_off), "int", "split_base_type_name");

        /* BTF-to-C dump of split BTF */
        dump_buf_file = open_memstream(&dump_buf, &dump_buf_sz);
        if (!ASSERT_OK_PTR(dump_buf_file, "dump_memstream"))
                return;
        d = btf_dump__new(btf3, btf_dump_printf, dump_buf_file, NULL);
        if (!ASSERT_OK_PTR(d, "btf_dump__new"))
                goto cleanup;
        for (i = 1; i < btf__type_cnt(btf3); i++) {
                err = btf_dump__dump_type(d, i);
                ASSERT_OK(err, "dump_type_ok");
        }
        fflush(dump_buf_file);
        dump_buf[dump_buf_sz] = 0; /* some libc implementations don't do this */
        ASSERT_STREQ(dump_buf,
"struct s1 {\n"
"       int f1;\n"
"};\n\n"
"struct s2 {\n"
"       struct s1 f1;\n"
"       int f2;\n"
"       int *f3;\n"
"};\n\n"
"union u1 {\n"
"       struct s2 f1;\n"
"       int uf2;\n"
"};\n\n", "c_dump");

        /* write base, split BTFs to files and ensure parsing succeeds */
        base_btf_sz = btf_raw_write(btf1, base_btf_file);
        if (base_btf_sz < 0)
                goto cleanup;
        split_btf_sz = btf_raw_write(btf2, split_btf_file);
        if (split_btf_sz < 0)
                goto cleanup;
        btf4 = btf__parse(base_btf_file, NULL);
        if (!ASSERT_OK_PTR(btf4, "parse_base"))
                goto cleanup;
        btf5 = btf__parse_split(split_btf_file, btf4);
        if (!ASSERT_OK_PTR(btf5, "parse_split"))
                goto cleanup;
        if (multi) {
                multisplit_btf_sz = btf_raw_write(btf3, multisplit_btf_file);
                if (multisplit_btf_sz < 0)
                        goto cleanup;
                btf6 = btf__parse_split(multisplit_btf_file, btf5);
                if (!ASSERT_OK_PTR(btf6, "parse_multisplit"))
                        goto cleanup;
        } else {
                btf6 = btf5;
        }

        if (!ASSERT_EQ(btf__type_cnt(btf3), btf__type_cnt(btf6), "cmp_type_cnt"))
                goto cleanup;

        /* compare parsed to original BTF */
        for (i = 1; i < btf__type_cnt(btf6); i++) {
                t = btf__type_by_id(btf6, i);
                if (!ASSERT_OK_PTR(t, "type_in_parsed_btf"))
                        goto cleanup;
                ot = btf__type_by_id(btf3, i);
                if (!ASSERT_OK_PTR(ot, "type_in_orig_btf"))
                        goto cleanup;
                if (!ASSERT_EQ(memcmp(t, ot, sizeof(*ot)), 0, "cmp_parsed_orig_btf"))
                        goto cleanup;
        }

cleanup:
        if (dump_buf_file)
                fclose(dump_buf_file);
        free(dump_buf);
        btf_dump__free(d);
        btf__free(btf1);
        btf__free(btf2);
        if (btf2 != btf3)
                btf__free(btf3);
        btf__free(btf4);
        btf__free(btf5);
        if (btf5 != btf6)
                btf__free(btf6);
        if (base_btf_sz > 0)
                unlink(base_btf_file);
        if (split_btf_sz > 0)
                unlink(split_btf_file);
        if (multisplit_btf_sz > 0)
                unlink(multisplit_btf_file);
}

void test_btf_split(void)
{
        if (test__start_subtest("single_split"))
                __test_btf_split(false);
        if (test__start_subtest("multi_split"))
                __test_btf_split(true);
}