1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * KUnit test for struct string_stream.
  4 *
  5 * Copyright (C) 2019, Google LLC.
  6 * Author: Brendan Higgins <brendanhiggins@google.com>
  7 */
  8
  9#include <kunit/static_stub.h>
 10#include <kunit/test.h>
 11#include <linux/ktime.h>
 12#include <linux/prandom.h>
 13#include <linux/slab.h>
 14#include <linux/timekeeping.h>
 15
 16#include "string-stream.h"
 17
 18struct string_stream_test_priv {
 19	/* For testing resource-managed free. */
 20	struct string_stream *expected_free_stream;
 21	bool stream_was_freed;
 22	bool stream_free_again;
 23};
 24
 25/* Avoids a cast warning if kfree() is passed direct to kunit_add_action(). */
 26KUNIT_DEFINE_ACTION_WRAPPER(kfree_wrapper, kfree, const void *);
 27
 28/* Avoids a cast warning if string_stream_destroy() is passed direct to kunit_add_action(). */
 29KUNIT_DEFINE_ACTION_WRAPPER(cleanup_raw_stream, string_stream_destroy, struct string_stream *);
 30
 31static char *get_concatenated_string(struct kunit *test, struct string_stream *stream)
 32{
 33	char *str = string_stream_get_string(stream);
 34
 35	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, str);
 36	kunit_add_action(test, kfree_wrapper, (void *)str);
 37
 38	return str;
 39}
 40
 41/* Managed string_stream object is initialized correctly. */
 42static void string_stream_managed_init_test(struct kunit *test)
 43{
 44	struct string_stream *stream;
 45
 46	/* Resource-managed initialization. */
 47	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
 48	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
 49
 50	KUNIT_EXPECT_EQ(test, stream->length, 0);
 51	KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
 52	KUNIT_EXPECT_TRUE(test, (stream->gfp == GFP_KERNEL));
 53	KUNIT_EXPECT_FALSE(test, stream->append_newlines);
 54	KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
 55}
 56
 57/* Unmanaged string_stream object is initialized correctly. */
 58static void string_stream_unmanaged_init_test(struct kunit *test)
 59{
 60	struct string_stream *stream;
 61
 62	stream = alloc_string_stream(GFP_KERNEL);
 63	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
 64	kunit_add_action(test, cleanup_raw_stream, stream);
 65
 66	KUNIT_EXPECT_EQ(test, stream->length, 0);
 67	KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
 68	KUNIT_EXPECT_TRUE(test, (stream->gfp == GFP_KERNEL));
 69	KUNIT_EXPECT_FALSE(test, stream->append_newlines);
 70
 71	KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
 72}
 73
 74static void string_stream_destroy_stub(struct string_stream *stream)
 75{
 76	struct kunit *fake_test = kunit_get_current_test();
 77	struct string_stream_test_priv *priv = fake_test->priv;
 78
 79	/* The kunit could own string_streams other than the one we are testing. */
 80	if (stream == priv->expected_free_stream) {
 81		if (priv->stream_was_freed)
 82			priv->stream_free_again = true;
 83		else
 84			priv->stream_was_freed = true;
 85	}
 86
 87	/*
 88	 * Calling string_stream_destroy() will only call this function again
 89	 * because the redirection stub is still active.
 90	 * Avoid calling deactivate_static_stub() or changing current->kunit_test
 91	 * during cleanup.
 92	 */
 93	string_stream_clear(stream);
 94	kfree(stream);
 95}
 96
 97/* kunit_free_string_stream() calls string_stream_desrtoy() */
 98static void string_stream_managed_free_test(struct kunit *test)
 99{
100	struct string_stream_test_priv *priv = test->priv;
101
102	priv->expected_free_stream = NULL;
103	priv->stream_was_freed = false;
104	priv->stream_free_again = false;
105
106	kunit_activate_static_stub(test,
107				   string_stream_destroy,
108				   string_stream_destroy_stub);
109
110	priv->expected_free_stream = kunit_alloc_string_stream(test, GFP_KERNEL);
111	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->expected_free_stream);
112
113	/* This should call the stub function. */
114	kunit_free_string_stream(test, priv->expected_free_stream);
115
116	KUNIT_EXPECT_TRUE(test, priv->stream_was_freed);
117	KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
118}
119
120/* string_stream object is freed when test is cleaned up. */
121static void string_stream_resource_free_test(struct kunit *test)
122{
123	struct string_stream_test_priv *priv = test->priv;
124	struct kunit *fake_test;
125
126	fake_test = kunit_kzalloc(test, sizeof(*fake_test), GFP_KERNEL);
127	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fake_test);
128
129	kunit_init_test(fake_test, "string_stream_fake_test", NULL);
130	fake_test->priv = priv;
131
132	/*
133	 * Activate stub before creating string_stream so the
134	 * string_stream will be cleaned up first.
135	 */
136	priv->expected_free_stream = NULL;
137	priv->stream_was_freed = false;
138	priv->stream_free_again = false;
139
140	kunit_activate_static_stub(fake_test,
141				   string_stream_destroy,
142				   string_stream_destroy_stub);
143
144	priv->expected_free_stream = kunit_alloc_string_stream(fake_test, GFP_KERNEL);
145	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->expected_free_stream);
146
147	/* Set current->kunit_test to fake_test so the static stub will be called. */
148	current->kunit_test = fake_test;
149
150	/* Cleanup test - the stub function should be called */
151	kunit_cleanup(fake_test);
152
153	/* Set current->kunit_test back to current test. */
154	current->kunit_test = test;
155
156	KUNIT_EXPECT_TRUE(test, priv->stream_was_freed);
157	KUNIT_EXPECT_FALSE(test, priv->stream_free_again);
158}
159
160/*
161 * Add a series of lines to a string_stream. Check that all lines
162 * appear in the correct order and no characters are dropped.
163 */
164static void string_stream_line_add_test(struct kunit *test)
165{
166	struct string_stream *stream;
167	char line[60];
168	char *concat_string, *pos, *string_end;
169	size_t len, total_len;
170	int num_lines, i;
171
172	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
173	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
174
175	/* Add series of sequence numbered lines */
176	total_len = 0;
177	for (i = 0; i < 100; ++i) {
178		len = snprintf(line, sizeof(line),
179			"The quick brown fox jumps over the lazy penguin %d\n", i);
180
181		/* Sanity-check that our test string isn't truncated */
182		KUNIT_ASSERT_LT(test, len, sizeof(line));
183
184		string_stream_add(stream, line);
185		total_len += len;
186	}
187	num_lines = i;
188
189	concat_string = get_concatenated_string(test, stream);
190	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, concat_string);
191	KUNIT_EXPECT_EQ(test, strlen(concat_string), total_len);
192
193	/*
194	 * Split the concatenated string at the newlines and check that
195	 * all the original added strings are present.
196	 */
197	pos = concat_string;
198	for (i = 0; i < num_lines; ++i) {
199		string_end = strchr(pos, '\n');
200		KUNIT_EXPECT_NOT_NULL(test, string_end);
201
202		/* Convert to NULL-terminated string */
203		*string_end = '\0';
204
205		snprintf(line, sizeof(line),
206			 "The quick brown fox jumps over the lazy penguin %d", i);
207		KUNIT_EXPECT_STREQ(test, pos, line);
208
209		pos = string_end + 1;
210	}
211
212	/* There shouldn't be any more data after this */
213	KUNIT_EXPECT_EQ(test, strlen(pos), 0);
214}
215
216/* Add a series of lines of variable length to a string_stream. */
217static void string_stream_variable_length_line_test(struct kunit *test)
218{
219	static const char line[] =
220		"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
221		" 0123456789!$%^&*()_-+={}[]:;@'~#<>,.?/|";
222	struct string_stream *stream;
223	struct rnd_state rnd;
224	char *concat_string, *pos, *string_end;
225	size_t offset, total_len;
226	int num_lines, i;
227
228	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
229	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
230
231	/*
232	 * Log many lines of varying lengths until we have created
233	 * many fragments.
234	 * The "randomness" must be repeatable.
235	 */
236	prandom_seed_state(&rnd, 3141592653589793238ULL);
237	total_len = 0;
238	for (i = 0; i < 100; ++i) {
239		offset = prandom_u32_state(&rnd) % (sizeof(line) - 1);
240		string_stream_add(stream, "%s\n", &line[offset]);
241		total_len += sizeof(line) - offset;
242	}
243	num_lines = i;
244
245	concat_string = get_concatenated_string(test, stream);
246	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, concat_string);
247	KUNIT_EXPECT_EQ(test, strlen(concat_string), total_len);
248
249	/*
250	 * Split the concatenated string at the newlines and check that
251	 * all the original added strings are present.
252	 */
253	prandom_seed_state(&rnd, 3141592653589793238ULL);
254	pos = concat_string;
255	for (i = 0; i < num_lines; ++i) {
256		string_end = strchr(pos, '\n');
257		KUNIT_EXPECT_NOT_NULL(test, string_end);
258
259		/* Convert to NULL-terminated string */
260		*string_end = '\0';
261
262		offset = prandom_u32_state(&rnd) % (sizeof(line) - 1);
263		KUNIT_EXPECT_STREQ(test, pos, &line[offset]);
264
265		pos = string_end + 1;
266	}
267
268	/* There shouldn't be any more data after this */
269	KUNIT_EXPECT_EQ(test, strlen(pos), 0);
270}
271
272/* Appending the content of one string stream to another. */
273static void string_stream_append_test(struct kunit *test)
274{
275	static const char * const strings_1[] = {
276		"one", "two", "three", "four", "five", "six",
277		"seven", "eight", "nine", "ten",
278	};
279	static const char * const strings_2[] = {
280		"Apple", "Pear", "Orange", "Banana", "Grape", "Apricot",
281	};
282	struct string_stream *stream_1, *stream_2;
283	const char *stream1_content_before_append, *stream_2_content;
284	char *combined_content;
285	size_t combined_length;
286	int i;
287
288	stream_1 = kunit_alloc_string_stream(test, GFP_KERNEL);
289	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_1);
290
291	stream_2 = kunit_alloc_string_stream(test, GFP_KERNEL);
292	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_2);
293
294	/* Append content of empty stream to empty stream */
295	string_stream_append(stream_1, stream_2);
296	KUNIT_EXPECT_EQ(test, strlen(get_concatenated_string(test, stream_1)), 0);
297
298	/* Add some data to stream_1 */
299	for (i = 0; i < ARRAY_SIZE(strings_1); ++i)
300		string_stream_add(stream_1, "%s\n", strings_1[i]);
301
302	stream1_content_before_append = get_concatenated_string(test, stream_1);
303
304	/* Append content of empty stream to non-empty stream */
305	string_stream_append(stream_1, stream_2);
306	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1),
307			   stream1_content_before_append);
308
309	/* Add some data to stream_2 */
310	for (i = 0; i < ARRAY_SIZE(strings_2); ++i)
311		string_stream_add(stream_2, "%s\n", strings_2[i]);
312
313	/* Append content of non-empty stream to non-empty stream */
314	string_stream_append(stream_1, stream_2);
315
316	/*
317	 * End result should be the original content of stream_1 plus
318	 * the content of stream_2.
319	 */
320	stream_2_content = get_concatenated_string(test, stream_2);
321	combined_length = strlen(stream1_content_before_append) + strlen(stream_2_content);
322	combined_length++; /* for terminating \0 */
323	combined_content = kunit_kmalloc(test, combined_length, GFP_KERNEL);
324	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, combined_content);
325	snprintf(combined_content, combined_length, "%s%s",
326		 stream1_content_before_append, stream_2_content);
327
328	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1), combined_content);
329
330	/* Append content of non-empty stream to empty stream */
331	kunit_free_string_stream(test, stream_1);
332
333	stream_1 = kunit_alloc_string_stream(test, GFP_KERNEL);
334	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_1);
335
336	string_stream_append(stream_1, stream_2);
337	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1), stream_2_content);
338}
339
340/* Appending the content of one string stream to one with auto-newlining. */
341static void string_stream_append_auto_newline_test(struct kunit *test)
342{
343	struct string_stream *stream_1, *stream_2;
344
345	/* Stream 1 has newline appending enabled */
346	stream_1 = kunit_alloc_string_stream(test, GFP_KERNEL);
347	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_1);
348	string_stream_set_append_newlines(stream_1, true);
349	KUNIT_EXPECT_TRUE(test, stream_1->append_newlines);
350
351	/* Stream 2 does not append newlines */
352	stream_2 = kunit_alloc_string_stream(test, GFP_KERNEL);
353	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_2);
354
355	/* Appending a stream with a newline should not add another newline */
356	string_stream_add(stream_1, "Original string\n");
357	string_stream_add(stream_2, "Appended content\n");
358	string_stream_add(stream_2, "More stuff\n");
359	string_stream_append(stream_1, stream_2);
360	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1),
361			   "Original string\nAppended content\nMore stuff\n");
362
363	kunit_free_string_stream(test, stream_2);
364	stream_2 = kunit_alloc_string_stream(test, GFP_KERNEL);
365	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream_2);
366
367	/*
368	 * Appending a stream without newline should add a final newline.
369	 * The appended string_stream is treated as a single string so newlines
370	 * should not be inserted between fragments.
371	 */
372	string_stream_add(stream_2, "Another");
373	string_stream_add(stream_2, "And again");
374	string_stream_append(stream_1, stream_2);
375	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream_1),
376			   "Original string\nAppended content\nMore stuff\nAnotherAnd again\n");
377}
378
379/* Adding an empty string should not create a fragment. */
380static void string_stream_append_empty_string_test(struct kunit *test)
381{
382	struct string_stream *stream;
383	int original_frag_count;
384
385	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
386	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
387
388	/* Formatted empty string */
389	string_stream_add(stream, "%s", "");
390	KUNIT_EXPECT_TRUE(test, string_stream_is_empty(stream));
391	KUNIT_EXPECT_TRUE(test, list_empty(&stream->fragments));
392
393	/* Adding an empty string to a non-empty stream */
394	string_stream_add(stream, "Add this line");
395	original_frag_count = list_count_nodes(&stream->fragments);
396
397	string_stream_add(stream, "%s", "");
398	KUNIT_EXPECT_EQ(test, list_count_nodes(&stream->fragments), original_frag_count);
399	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream), "Add this line");
400}
401
402/* Adding strings without automatic newline appending */
403static void string_stream_no_auto_newline_test(struct kunit *test)
404{
405	struct string_stream *stream;
406
407	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
408	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
409
410	/*
411	 * Add some strings with and without newlines. All formatted newlines
412	 * should be preserved. It should not add any extra newlines.
413	 */
414	string_stream_add(stream, "One");
415	string_stream_add(stream, "Two\n");
416	string_stream_add(stream, "%s\n", "Three");
417	string_stream_add(stream, "%s", "Four\n");
418	string_stream_add(stream, "Five\n%s", "Six");
419	string_stream_add(stream, "Seven\n\n");
420	string_stream_add(stream, "Eight");
421	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream),
422			   "OneTwo\nThree\nFour\nFive\nSixSeven\n\nEight");
423}
424
425/* Adding strings with automatic newline appending */
426static void string_stream_auto_newline_test(struct kunit *test)
427{
428	struct string_stream *stream;
429
430	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
431	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
432
433	string_stream_set_append_newlines(stream, true);
434	KUNIT_EXPECT_TRUE(test, stream->append_newlines);
435
436	/*
437	 * Add some strings with and without newlines. Newlines should
438	 * be appended to lines that do not end with \n, but newlines
439	 * resulting from the formatting should not be changed.
440	 */
441	string_stream_add(stream, "One");
442	string_stream_add(stream, "Two\n");
443	string_stream_add(stream, "%s\n", "Three");
444	string_stream_add(stream, "%s", "Four\n");
445	string_stream_add(stream, "Five\n%s", "Six");
446	string_stream_add(stream, "Seven\n\n");
447	string_stream_add(stream, "Eight");
448	KUNIT_EXPECT_STREQ(test, get_concatenated_string(test, stream),
449			   "One\nTwo\nThree\nFour\nFive\nSix\nSeven\n\nEight\n");
450}
451
452/*
453 * This doesn't actually "test" anything. It reports time taken
454 * and memory used for logging a large number of lines.
455 */
456static void string_stream_performance_test(struct kunit *test)
457{
458	struct string_stream_fragment *frag_container;
459	struct string_stream *stream;
460	char test_line[101];
461	ktime_t start_time, end_time;
462	size_t len, bytes_requested, actual_bytes_used, total_string_length;
463	int offset, i;
464
465	stream = kunit_alloc_string_stream(test, GFP_KERNEL);
466	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, stream);
467
468	memset(test_line, 'x', sizeof(test_line) - 1);
469	test_line[sizeof(test_line) - 1] = '\0';
470
471	start_time = ktime_get();
472	for (i = 0; i < 10000; i++) {
473		offset = i % (sizeof(test_line) - 1);
474		string_stream_add(stream, "%s: %d\n", &test_line[offset], i);
475	}
476	end_time = ktime_get();
477
478	/*
479	 * Calculate memory used. This doesn't include invisible
480	 * overhead due to kernel allocator fragment size rounding.
481	 */
482	bytes_requested = sizeof(*stream);
483	actual_bytes_used = ksize(stream);
484	total_string_length = 0;
485
486	list_for_each_entry(frag_container, &stream->fragments, node) {
487		bytes_requested += sizeof(*frag_container);
488		actual_bytes_used += ksize(frag_container);
489
490		len = strlen(frag_container->fragment);
491		total_string_length += len;
492		bytes_requested += len + 1; /* +1 for '\0' */
493		actual_bytes_used += ksize(frag_container->fragment);
494	}
495
496	kunit_info(test, "Time elapsed:           %lld us\n",
497		   ktime_us_delta(end_time, start_time));
498	kunit_info(test, "Total string length:    %zu\n", total_string_length);
499	kunit_info(test, "Bytes requested:        %zu\n", bytes_requested);
500	kunit_info(test, "Actual bytes allocated: %zu\n", actual_bytes_used);
501}
502
503static int string_stream_test_init(struct kunit *test)
504{
505	struct string_stream_test_priv *priv;
506
507	priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
508	if (!priv)
509		return -ENOMEM;
510
511	test->priv = priv;
512
513	return 0;
514}
515
516static struct kunit_case string_stream_test_cases[] = {
517	KUNIT_CASE(string_stream_managed_init_test),
518	KUNIT_CASE(string_stream_unmanaged_init_test),
519	KUNIT_CASE(string_stream_managed_free_test),
520	KUNIT_CASE(string_stream_resource_free_test),
521	KUNIT_CASE(string_stream_line_add_test),
522	KUNIT_CASE(string_stream_variable_length_line_test),
523	KUNIT_CASE(string_stream_append_test),
524	KUNIT_CASE(string_stream_append_auto_newline_test),
525	KUNIT_CASE(string_stream_append_empty_string_test),
526	KUNIT_CASE(string_stream_no_auto_newline_test),
527	KUNIT_CASE(string_stream_auto_newline_test),
528	KUNIT_CASE(string_stream_performance_test),
529	{}
530};
531
532static struct kunit_suite string_stream_test_suite = {
533	.name = "string-stream-test",
534	.test_cases = string_stream_test_cases,
535	.init = string_stream_test_init,
536};
537kunit_test_suites(&string_stream_test_suite);