// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/* Copyright (c) 2025 Isovalent */

#include <test_progs.h>
#include <bpf/btf.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <unistd.h>

static void test_btf_mmap_sysfs(const char *path, struct btf *base)
{
        struct stat st;
        __u64 btf_size, end;
        void *raw_data = NULL;
        int fd = -1;
        long page_size;
        struct btf *btf = NULL;

        page_size = sysconf(_SC_PAGESIZE);
        if (!ASSERT_GE(page_size, 0, "get_page_size"))
                goto cleanup;

        if (!ASSERT_OK(stat(path, &st), "stat_btf"))
                goto cleanup;

        btf_size = st.st_size;
        end = (btf_size + page_size - 1) / page_size * page_size;

        fd = open(path, O_RDONLY);
        if (!ASSERT_GE(fd, 0, "open_btf"))
                goto cleanup;

        raw_data = mmap(NULL, btf_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
        if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_writable"))
                goto cleanup;

        raw_data = mmap(NULL, btf_size, PROT_READ, MAP_SHARED, fd, 0);
        if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_shared"))
                goto cleanup;

        raw_data = mmap(NULL, end + 1, PROT_READ, MAP_PRIVATE, fd, 0);
        if (!ASSERT_EQ(raw_data, MAP_FAILED, "mmap_btf_invalid_size"))
                goto cleanup;

        raw_data = mmap(NULL, end, PROT_READ, MAP_PRIVATE, fd, 0);
        if (!ASSERT_OK_PTR(raw_data, "mmap_btf"))
                goto cleanup;

        if (!ASSERT_EQ(mprotect(raw_data, btf_size, PROT_READ | PROT_WRITE), -1,
            "mprotect_writable"))
                goto cleanup;

        if (!ASSERT_EQ(mprotect(raw_data, btf_size, PROT_READ | PROT_EXEC), -1,
            "mprotect_executable"))
                goto cleanup;

        /* Check padding is zeroed */
        for (int i = btf_size; i < end; i++) {
                if (((__u8 *)raw_data)[i] != 0) {
                        PRINT_FAIL("tail of BTF is not zero at page offset %d\n", i);
                        goto cleanup;
                }
        }

        btf = btf__new_split(raw_data, btf_size, base);
        if (!ASSERT_OK_PTR(btf, "parse_btf"))
                goto cleanup;

cleanup:
        btf__free(btf);
        if (raw_data && raw_data != MAP_FAILED)
                munmap(raw_data, btf_size);
        if (fd >= 0)
                close(fd);
}

void test_btf_sysfs(void)
{
        test_btf_mmap_sysfs("/sys/kernel/btf/vmlinux", NULL);
}