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// 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(int len, gfp_t gfp)
{
struct string_stream_fragment *frag;
frag = kzalloc(sizeof(*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 = strlcat(frag_container->fragment, "\n", buf_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. */
char *buf;
buf = kzalloc(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;
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(sizeof(*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)
{
if (!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);
}
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