// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */

#include <test_progs.h>
#include <network_helpers.h>
#include "file_reader.skel.h"
#include "file_reader_fail.skel.h"
#include <dlfcn.h>
#include <sys/mman.h>

const char *user_ptr = "hello world";
char file_contents[256000];

void *get_executable_base_addr(void)
{
        Dl_info info;

        if (!dladdr((void *)&get_executable_base_addr, &info)) {
                fprintf(stderr, "dladdr failed\n");
                return NULL;
        }

        return info.dli_fbase;
}

static int initialize_file_contents(void)
{
        int fd, page_sz = sysconf(_SC_PAGESIZE);
        ssize_t n = 0, cur, off;
        void *addr;

        fd = open("/proc/self/exe", O_RDONLY);
        if (!ASSERT_OK_FD(fd, "Open /proc/self/exe\n"))
                return 1;

        do {
                cur = read(fd, file_contents + n, sizeof(file_contents) - n);
                if (!ASSERT_GT(cur, 0, "read success"))
                        break;
                n += cur;
        } while (n < sizeof(file_contents));

        close(fd);

        if (!ASSERT_EQ(n, sizeof(file_contents), "Read /proc/self/exe\n"))
                return 1;

        addr = get_executable_base_addr();
        if (!ASSERT_NEQ(addr, NULL, "get executable address"))
                return 1;

        /* page-align base file address */
        addr = (void *)((unsigned long)addr & ~(page_sz - 1));

        /*
         * Page out range 0..512K, use 0..256K for positive tests and
         * 256K..512K for negative tests expecting page faults
         */
        for (off = 0; off < sizeof(file_contents) * 2; off += page_sz) {
                if (!ASSERT_OK(madvise(addr + off, page_sz, MADV_PAGEOUT),
                               "madvise pageout"))
                        return errno;
        }

        return 0;
}

static void run_test(const char *prog_name)
{
        struct file_reader *skel;
        struct bpf_program *prog;
        int err, fd;

        err = initialize_file_contents();
        if (!ASSERT_OK(err, "initialize file contents"))
                return;

        skel = file_reader__open();
        if (!ASSERT_OK_PTR(skel, "file_reader__open"))
                return;

        bpf_object__for_each_program(prog, skel->obj) {
                bpf_program__set_autoload(prog, strcmp(bpf_program__name(prog), prog_name) == 0);
        }

        memcpy(skel->bss->user_buf, file_contents, sizeof(file_contents));
        skel->bss->pid = getpid();

        err = file_reader__load(skel);
        if (!ASSERT_OK(err, "file_reader__load"))
                goto cleanup;

        err = file_reader__attach(skel);
        if (!ASSERT_OK(err, "file_reader__attach"))
                goto cleanup;

        fd = open("/proc/self/exe", O_RDONLY);
        if (fd >= 0)
                close(fd);

        ASSERT_EQ(skel->bss->err, 0, "err");
        ASSERT_EQ(skel->bss->run_success, 1, "run_success");
cleanup:
        file_reader__destroy(skel);
}

void test_file_reader(void)
{
        if (test__start_subtest("on_open_expect_fault"))
                run_test("on_open_expect_fault");

        if (test__start_subtest("on_open_validate_file_read"))
                run_test("on_open_validate_file_read");

        if (test__start_subtest("negative"))
                RUN_TESTS(file_reader_fail);
}