// SPDX-License-Identifier: GPL-2.0
/*
 * KUnit test for struct string_stream.
 *
 * Copyright (C) 2019, Google LLC.
 * Author: Brendan Higgins <brendanhiggins@google.com>
 */

#include <kunit/static_stub.h>
#include <kunit/test.h>
#include <linux/ktime.h>
#include <linux/prandom.h>
#include <linux/slab.h>
#include <linux/timekeeping.h>

#include "string-stream.h"

struct string_stream_test_priv {
        /* For testing resource-managed free. */
        struct string_stream *expected_free_stream;
        bool stream_was_freed;
        bool stream_free_again;
};

/* Avoids a cast warning if kfree() is passed direct to kunit_add_action(). */
KUNIT_DEFINE_ACTION_WRAPPER(kfree_wrapper, kfree, const void *);

/* Avoids a cast warning if string_stream_destroy() is passed direct to kunit_add_action(). */
KUNIT_DEFINE_ACTION_WRAPPER(cleanup_raw_stream, string_stream_destroy, struct string_stream *);

static char *get_concatenated_string(struct kunit *test, struct string_stream *stream)
{
        char *str = string_stream_get_string(stream);

        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, str);
        kunit_add_action(test, kfree_wrapper, (void *)str);

        return str;
}

/* Managed string_stream object is initialized correctly. */
static void string_stream_managed_init_test(struct kunit *test)
{
        struct string_stream *stream;

        /* Resource-managed initialization. */
        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        KUNIT_EXPECT_EQ(test, stream->length, 0);
        KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
        KUNIT_EXPECT_TRUE(test, (stream->gfp == GFP_KERNEL));
        KUNIT_EXPECT_FALSE(test, stream->append_newlines);
        KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
}

/* Unmanaged string_stream object is initialized correctly. */
static void string_stream_unmanaged_init_test(struct kunit *test)
{
        struct string_stream *stream;

        stream = alloc_string_stream(GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
        kunit_add_action(test, cleanup_raw_stream, stream);

        KUNIT_EXPECT_EQ(test, stream->length, 0);
        KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
        KUNIT_EXPECT_TRUE(test, (stream->gfp == GFP_KERNEL));
        KUNIT_EXPECT_FALSE(test, stream->append_newlines);

        KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
}

static void string_stream_destroy_stub(struct string_stream *stream)
{
        struct kunit *fake_test = kunit_get_current_test();
        struct string_stream_test_priv *priv = fake_test->priv;

        /* The kunit could own string_streams other than the one we are testing. */
        if (stream == priv->expected_free_stream) {
                if (priv->stream_was_freed)
                        priv->stream_free_again = true;
                else
                        priv->stream_was_freed = true;
        }

        /*
         * Calling string_stream_destroy() will only call this function again
         * because the redirection stub is still active.
         * Avoid calling deactivate_static_stub() or changing current->kunit_test
         * during cleanup.
         */
        string_stream_clear(stream);
        kfree(stream);
}

/* kunit_free_string_stream() calls string_stream_desrtoy() */
static void string_stream_managed_free_test(struct kunit *test)
{
        struct string_stream_test_priv *priv = test->priv;

        priv->expected_free_stream = NULL;
        priv->stream_was_freed = false;
        priv->stream_free_again = false;

        kunit_activate_static_stub(test,
                                   string_stream_destroy,
                                   string_stream_destroy_stub);

        priv->expected_free_stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->expected_free_stream);

        /* This should call the stub function. */
        kunit_free_string_stream(test, priv->expected_free_stream);

        KUNIT_EXPECT_TRUE(test, priv->stream_was_freed);
        KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
}

/* string_stream object is freed when test is cleaned up. */
static void string_stream_resource_free_test(struct kunit *test)
{
        struct string_stream_test_priv *priv = test->priv;
        struct kunit *fake_test;

        fake_test = kunit_kzalloc(test, sizeof(*fake_test), GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fake_test);

        kunit_init_test(fake_test, "string_stream_fake_test", NULL);
        fake_test->priv = priv;

        /*
         * Activate stub before creating string_stream so the
         * string_stream will be cleaned up first.
         */
        priv->expected_free_stream = NULL;
        priv->stream_was_freed = false;
        priv->stream_free_again = false;

        kunit_activate_static_stub(fake_test,
                                   string_stream_destroy,
                                   string_stream_destroy_stub);

        priv->expected_free_stream = kunit_alloc_string_stream(fake_test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->expected_free_stream);

        /* Set current->kunit_test to fake_test so the static stub will be called. */
        current->kunit_test = fake_test;

        /* Cleanup test - the stub function should be called */
        kunit_cleanup(fake_test);

        /* Set current->kunit_test back to current test. */
        current->kunit_test = test;

        KUNIT_EXPECT_TRUE(test, priv->stream_was_freed);
        KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
}

/*
 * Add a series of lines to a string_stream. Check that all lines
 * appear in the correct order and no characters are dropped.
 */
static void string_stream_line_add_test(struct kunit *test)
{
        struct string_stream *stream;
        char line[60];
        char *concat_string, *pos, *string_end;
        size_t len, total_len;
        int num_lines, i;

        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        /* Add series of sequence numbered lines */
        total_len = 0;
        for (i = 0; i < 100; ++i) {
                len = snprintf(line, sizeof(line),
                        "The quick brown fox jumps over the lazy penguin %d\n", i);

                /* Sanity-check that our test string isn't truncated */
                KUNIT_ASSERT_LT(test, len, sizeof(line));

                string_stream_add(stream, line);
                total_len += len;
        }
        num_lines = i;

        concat_string = get_concatenated_string(test, stream);
        KUNIT_EXPECT_NOT_ERR_OR_NULL(test, concat_string);
        KUNIT_EXPECT_EQ(test, strlen(concat_string), total_len);

        /*
         * Split the concatenated string at the newlines and check that
         * all the original added strings are present.
         */
        pos = concat_string;
        for (i = 0; i < num_lines; ++i) {
                string_end = strchr(pos, '\n');
                KUNIT_EXPECT_NOT_NULL(test, string_end);

                /* Convert to NULL-terminated string */
                *string_end = '\0';

                snprintf(line, sizeof(line),
                         "The quick brown fox jumps over the lazy penguin %d", i);
                KUNIT_EXPECT_STREQ(test, pos, line);

                pos = string_end + 1;
        }

        /* There shouldn't be any more data after this */
        KUNIT_EXPECT_EQ(test, strlen(pos), 0);
}

/* Add a series of lines of variable length to a string_stream. */
static void string_stream_variable_length_line_test(struct kunit *test)
{
        static const char line[] =
                "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
                " 0123456789!$%^&*()_-+={}[]:;@'~#<>,.?/|";
        struct string_stream *stream;
        struct rnd_state rnd;
        char *concat_string, *pos, *string_end;
        size_t offset, total_len;
        int num_lines, i;

        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        /*
         * Log many lines of varying lengths until we have created
         * many fragments.
         * The "randomness" must be repeatable.
         */
        prandom_seed_state(&rnd, 3141592653589793238ULL);
        total_len = 0;
        for (i = 0; i < 100; ++i) {
                offset = prandom_u32_state(&rnd) % (sizeof(line) - 1);
                string_stream_add(stream, "%s\n", &line[offset]);
                total_len += sizeof(line) - offset;
        }
        num_lines = i;

        concat_string = get_concatenated_string(test, stream);
        KUNIT_EXPECT_NOT_ERR_OR_NULL(test, concat_string);
        KUNIT_EXPECT_EQ(test, strlen(concat_string), total_len);

        /*
         * Split the concatenated string at the newlines and check that
         * all the original added strings are present.
         */
        prandom_seed_state(&rnd, 3141592653589793238ULL);
        pos = concat_string;
        for (i = 0; i < num_lines; ++i) {
                string_end = strchr(pos, '\n');
                KUNIT_EXPECT_NOT_NULL(test, string_end);

                /* Convert to NULL-terminated string */
                *string_end = '\0';

                offset = prandom_u32_state(&rnd) % (sizeof(line) - 1);
                KUNIT_EXPECT_STREQ(test, pos, &line[offset]);

                pos = string_end + 1;
        }

        /* There shouldn't be any more data after this */
        KUNIT_EXPECT_EQ(test, strlen(pos), 0);
}

/* Appending the content of one string stream to another. */
static void string_stream_append_test(struct kunit *test)
{
        static const char * const strings_1[] = {
                "one", "two", "three", "four", "five", "six",
                "seven", "eight", "nine", "ten",
        };
        static const char * const strings_2[] = {
                "Apple", "Pear", "Orange", "Banana", "Grape", "Apricot",
        };
        struct string_stream *stream_1, *stream_2;
        const char *stream1_content_before_append, *stream_2_content;
        char *combined_content;
        size_t combined_length;
        int i;

        stream_1 = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_1);

        stream_2 = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_2);

        /* Append content of empty stream to empty stream */
        string_stream_append(stream_1, stream_2);
        KUNIT_EXPECT_EQ(test, strlen(get_concatenated_string(test, stream_1)), 0);

        /* Add some data to stream_1 */
        for (i = 0; i < ARRAY_SIZE(strings_1); ++i)
                string_stream_add(stream_1, "%s\n", strings_1[i]);

        stream1_content_before_append = get_concatenated_string(test, stream_1);

        /* Append content of empty stream to non-empty stream */
        string_stream_append(stream_1, stream_2);
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1),
                           stream1_content_before_append);

        /* Add some data to stream_2 */
        for (i = 0; i < ARRAY_SIZE(strings_2); ++i)
                string_stream_add(stream_2, "%s\n", strings_2[i]);

        /* Append content of non-empty stream to non-empty stream */
        string_stream_append(stream_1, stream_2);

        /*
         * End result should be the original content of stream_1 plus
         * the content of stream_2.
         */
        stream_2_content = get_concatenated_string(test, stream_2);
        combined_length = strlen(stream1_content_before_append) + strlen(stream_2_content);
        combined_length++; /* for terminating \0 */
        combined_content = kunit_kmalloc(test, combined_length, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, combined_content);
        snprintf(combined_content, combined_length, "%s%s",
                 stream1_content_before_append, stream_2_content);

        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1), combined_content);

        /* Append content of non-empty stream to empty stream */
        kunit_free_string_stream(test, stream_1);

        stream_1 = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_1);

        string_stream_append(stream_1, stream_2);
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1), stream_2_content);
}

/* Appending the content of one string stream to one with auto-newlining. */
static void string_stream_append_auto_newline_test(struct kunit *test)
{
        struct string_stream *stream_1, *stream_2;

        /* Stream 1 has newline appending enabled */
        stream_1 = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_1);
        string_stream_set_append_newlines(stream_1, true);
        KUNIT_EXPECT_TRUE(test, stream_1->append_newlines);

        /* Stream 2 does not append newlines */
        stream_2 = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_2);

        /* Appending a stream with a newline should not add another newline */
        string_stream_add(stream_1, "Original string\n");
        string_stream_add(stream_2, "Appended content\n");
        string_stream_add(stream_2, "More stuff\n");
        string_stream_append(stream_1, stream_2);
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1),
                           "Original string\nAppended content\nMore stuff\n");

        kunit_free_string_stream(test, stream_2);
        stream_2 = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_2);

        /*
         * Appending a stream without newline should add a final newline.
         * The appended string_stream is treated as a single string so newlines
         * should not be inserted between fragments.
         */
        string_stream_add(stream_2, "Another");
        string_stream_add(stream_2, "And again");
        string_stream_append(stream_1, stream_2);
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1),
                           "Original string\nAppended content\nMore stuff\nAnotherAnd again\n");
}

/* Adding an empty string should not create a fragment. */
static void string_stream_append_empty_string_test(struct kunit *test)
{
        struct string_stream *stream;
        int original_frag_count;

        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        /* Formatted empty string */
        string_stream_add(stream, "%s", "");
        KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
        KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));

        /* Adding an empty string to a non-empty stream */
        string_stream_add(stream, "Add this line");
        original_frag_count = list_count_nodes(&stream->fragments);

        string_stream_add(stream, "%s", "");
        KUNIT_EXPECT_EQ(test, list_count_nodes(&stream->fragments), original_frag_count);
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream), "Add this line");
}

/* Adding strings without automatic newline appending */
static void string_stream_no_auto_newline_test(struct kunit *test)
{
        struct string_stream *stream;

        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        /*
         * Add some strings with and without newlines. All formatted newlines
         * should be preserved. It should not add any extra newlines.
         */
        string_stream_add(stream, "One");
        string_stream_add(stream, "Two\n");
        string_stream_add(stream, "%s\n", "Three");
        string_stream_add(stream, "%s", "Four\n");
        string_stream_add(stream, "Five\n%s", "Six");
        string_stream_add(stream, "Seven\n\n");
        string_stream_add(stream, "Eight");
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream),
                           "OneTwo\nThree\nFour\nFive\nSixSeven\n\nEight");
}

/* Adding strings with automatic newline appending */
static void string_stream_auto_newline_test(struct kunit *test)
{
        struct string_stream *stream;

        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        string_stream_set_append_newlines(stream, true);
        KUNIT_EXPECT_TRUE(test, stream->append_newlines);

        /*
         * Add some strings with and without newlines. Newlines should
         * be appended to lines that do not end with \n, but newlines
         * resulting from the formatting should not be changed.
         */
        string_stream_add(stream, "One");
        string_stream_add(stream, "Two\n");
        string_stream_add(stream, "%s\n", "Three");
        string_stream_add(stream, "%s", "Four\n");
        string_stream_add(stream, "Five\n%s", "Six");
        string_stream_add(stream, "Seven\n\n");
        string_stream_add(stream, "Eight");
        KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream),
                           "One\nTwo\nThree\nFour\nFive\nSix\nSeven\n\nEight\n");
}

/*
 * This doesn't actually "test" anything. It reports time taken
 * and memory used for logging a large number of lines.
 */
static void string_stream_performance_test(struct kunit *test)
{
        struct string_stream_fragment *frag_container;
        struct string_stream *stream;
        char test_line[101];
        ktime_t start_time, end_time;
        size_t len, bytes_requested, actual_bytes_used, total_string_length;
        int offset, i;

        stream = kunit_alloc_string_stream(test, GFP_KERNEL);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);

        memset(test_line, 'x', sizeof(test_line) - 1);
        test_line[sizeof(test_line) - 1] = '\0';

        start_time = ktime_get();
        for (i = 0; i < 10000; i++) {
                offset = i % (sizeof(test_line) - 1);
                string_stream_add(stream, "%s: %d\n", &test_line[offset], i);
        }
        end_time = ktime_get();

        /*
         * Calculate memory used. This doesn't include invisible
         * overhead due to kernel allocator fragment size rounding.
         */
        bytes_requested = sizeof(*stream);
        actual_bytes_used = ksize(stream);
        total_string_length = 0;

        list_for_each_entry(frag_container, &stream->fragments, node) {
                bytes_requested += sizeof(*frag_container);
                actual_bytes_used += ksize(frag_container);

                len = strlen(frag_container->fragment);
                total_string_length += len;
                bytes_requested += len + 1; /* +1 for '\0' */
                actual_bytes_used += ksize(frag_container->fragment);
        }

        kunit_info(test, "Time elapsed:           %lld us\n",
                   ktime_us_delta(end_time, start_time));
        kunit_info(test, "Total string length:    %zu\n", total_string_length);
        kunit_info(test, "Bytes requested:        %zu\n", bytes_requested);
        kunit_info(test, "Actual bytes allocated: %zu\n", actual_bytes_used);
}

static int string_stream_test_init(struct kunit *test)
{
        struct string_stream_test_priv *priv;

        priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        test->priv = priv;

        return 0;
}

static struct kunit_case string_stream_test_cases[] = {
        KUNIT_CASE(string_stream_managed_init_test),
        KUNIT_CASE(string_stream_unmanaged_init_test),
        KUNIT_CASE(string_stream_managed_free_test),
        KUNIT_CASE(string_stream_resource_free_test),
        KUNIT_CASE(string_stream_line_add_test),
        KUNIT_CASE(string_stream_variable_length_line_test),
        KUNIT_CASE(string_stream_append_test),
        KUNIT_CASE(string_stream_append_auto_newline_test),
        KUNIT_CASE(string_stream_append_empty_string_test),
        KUNIT_CASE(string_stream_no_auto_newline_test),
        KUNIT_CASE(string_stream_auto_newline_test),
        KUNIT_CASE(string_stream_performance_test),
        {}
};

static struct kunit_suite string_stream_test_suite = {
        .name = "string-stream-test",
        .test_cases = string_stream_test_cases,
        .init = string_stream_test_init,
};
kunit_test_suites(&string_stream_test_suite);