// SPDX-License-Identifier: GPL-2.0/* * C++ stream style string builder used in KUnit for building messages. * * Copyright (C) 2019, Google LLC. * Author: Brendan Higgins <brendanhiggins@google.com> */ #include <kunit/test.h>#include <linux/list.h>#include <linux/slab.h> #include "string-stream.h"  static struct string_stream_fragment *alloc_string_stream_fragment(		struct kunit *test, int len, gfp_t gfp){	struct string_stream_fragment *frag; 	frag = kunit_kzalloc(test, sizeof(*frag), gfp);	if (!frag)		return ERR_PTR(-ENOMEM); 	frag->fragment = kunit_kmalloc(test, len, gfp);	if (!frag->fragment)		return ERR_PTR(-ENOMEM); 	return frag;} static void string_stream_fragment_destroy(struct kunit *test,					   struct string_stream_fragment *frag){	list_del(&frag->node);	kunit_kfree(test, frag->fragment);	kunit_kfree(test, frag);} int string_stream_vadd(struct string_stream *stream,		       const char *fmt,		       va_list args){	struct string_stream_fragment *frag_container;	int len;	va_list args_for_counting; 	/* Make a copy because `vsnprintf` could change it */	va_copy(args_for_counting, args); 	/* Need space for null byte. */	len = vsnprintf(NULL, 0, fmt, args_for_counting) + 1; 	va_end(args_for_counting); 	frag_container = alloc_string_stream_fragment(stream->test,						      len,						      stream->gfp);	if (IS_ERR(frag_container))		return PTR_ERR(frag_container); 	len = vsnprintf(frag_container->fragment, len, fmt, args);	spin_lock(&stream->lock);	stream->length += len;	list_add_tail(&frag_container->node, &stream->fragments);	spin_unlock(&stream->lock); 	return 0;} int string_stream_add(struct string_stream *stream, const char *fmt, ...){	va_list args;	int result; 	va_start(args, fmt);	result = string_stream_vadd(stream, fmt, args);	va_end(args); 	return result;} static void string_stream_clear(struct string_stream *stream){	struct string_stream_fragment *frag_container, *frag_container_safe; 	spin_lock(&stream->lock);	list_for_each_entry_safe(frag_container,				 frag_container_safe,				 &stream->fragments,				 node) {		string_stream_fragment_destroy(stream->test, frag_container);	}	stream->length = 0;	spin_unlock(&stream->lock);} char *string_stream_get_string(struct string_stream *stream){	struct string_stream_fragment *frag_container;	size_t buf_len = stream->length + 1; /* +1 for null byte. */	char *buf; 	buf = kunit_kzalloc(stream->test, buf_len, stream->gfp);	if (!buf)		return NULL; 	spin_lock(&stream->lock);	list_for_each_entry(frag_container, &stream->fragments, node)		strlcat(buf, frag_container->fragment, buf_len);	spin_unlock(&stream->lock); 	return buf;} int string_stream_append(struct string_stream *stream,			 struct string_stream *other){	const char *other_content; 	other_content = string_stream_get_string(other); 	if (!other_content)		return -ENOMEM; 	return string_stream_add(stream, other_content);} bool string_stream_is_empty(struct string_stream *stream){	return list_empty(&stream->fragments);} struct string_stream_alloc_context {	struct kunit *test;	gfp_t gfp;}; struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp){	struct string_stream *stream; 	stream = kunit_kzalloc(test, sizeof(*stream), gfp);	if (!stream)		return ERR_PTR(-ENOMEM); 	stream->gfp = gfp;	stream->test = test;	INIT_LIST_HEAD(&stream->fragments);	spin_lock_init(&stream->lock); 	return stream;} void string_stream_destroy(struct string_stream *stream){	string_stream_clear(stream);}