// 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/static_stub.h>#include <kunit/test.h>#include <linux/list.h>#include <linux/seq_buf.h>#include <linux/slab.h> #include "string-stream.h"  static struct string_stream_fragment *alloc_string_stream_fragment(int len, gfp_t gfp){	struct string_stream_fragment *frag; 	frag = kzalloc_obj(*frag, gfp);	if (!frag)		return ERR_PTR(-ENOMEM); 	frag->fragment = kmalloc(len, gfp);	if (!frag->fragment) {		kfree(frag);		return ERR_PTR(-ENOMEM);	} 	return frag;} static void string_stream_fragment_destroy(struct string_stream_fragment *frag){	list_del(&frag->node);	kfree(frag->fragment);	kfree(frag);} int string_stream_vadd(struct string_stream *stream,		       const char *fmt,		       va_list args){	struct string_stream_fragment *frag_container;	int buf_len, result_len;	va_list args_for_counting; 	/* Make a copy because `vsnprintf` could change it */	va_copy(args_for_counting, args); 	/* Evaluate length of formatted string */	buf_len = vsnprintf(NULL, 0, fmt, args_for_counting); 	va_end(args_for_counting); 	if (buf_len == 0)		return 0; 	/* Reserve one extra for possible appended newline. */	if (stream->append_newlines)		buf_len++; 	/* Need space for null byte. */	buf_len++; 	frag_container = alloc_string_stream_fragment(buf_len, stream->gfp);	if (IS_ERR(frag_container))		return PTR_ERR(frag_container); 	if (stream->append_newlines) {		/* Don't include reserved newline byte in writeable length. */		result_len = vsnprintf(frag_container->fragment, buf_len - 1, fmt, args); 		/* Append newline if necessary. */		if (frag_container->fragment[result_len - 1] != '\n')			result_len += strscpy(frag_container->fragment + result_len,					      "\n", buf_len - result_len);	} else {		result_len = vsnprintf(frag_container->fragment, buf_len, fmt, args);	} 	spin_lock(&stream->lock);	stream->length += result_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;} 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(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. */	struct seq_buf sb;	char *buf; 	buf = kzalloc(buf_len, stream->gfp);	if (!buf)		return NULL; 	seq_buf_init(&sb, buf, buf_len); 	spin_lock(&stream->lock);	list_for_each_entry(frag_container, &stream->fragments, node)		seq_buf_puts(&sb, frag_container->fragment);	spin_unlock(&stream->lock); 	return buf;} int string_stream_append(struct string_stream *stream,			 struct string_stream *other){	const char *other_content;	int ret; 	other_content = string_stream_get_string(other); 	if (!other_content)		return -ENOMEM; 	ret = string_stream_add(stream, other_content);	kfree(other_content); 	return ret;} bool string_stream_is_empty(struct string_stream *stream){	return list_empty(&stream->fragments);} struct string_stream *alloc_string_stream(gfp_t gfp){	struct string_stream *stream; 	stream = kzalloc_obj(*stream, gfp);	if (!stream)		return ERR_PTR(-ENOMEM); 	stream->gfp = gfp;	INIT_LIST_HEAD(&stream->fragments);	spin_lock_init(&stream->lock); 	return stream;} void string_stream_destroy(struct string_stream *stream){	KUNIT_STATIC_STUB_REDIRECT(string_stream_destroy, stream); 	if (IS_ERR_OR_NULL(stream))		return; 	string_stream_clear(stream);	kfree(stream);} static void resource_free_string_stream(void *p){	struct string_stream *stream = p; 	string_stream_destroy(stream);} struct string_stream *kunit_alloc_string_stream(struct kunit *test, gfp_t gfp){	struct string_stream *stream; 	stream = alloc_string_stream(gfp);	if (IS_ERR(stream))		return stream; 	if (kunit_add_action_or_reset(test, resource_free_string_stream, stream) != 0)		return ERR_PTR(-ENOMEM); 	return stream;} void kunit_free_string_stream(struct kunit *test, struct string_stream *stream){	kunit_release_action(test, resource_free_string_stream, (void *)stream);}