A number of test features need to do pretty complicated string printing where it may not be possible to rely on a single preallocated string with parameters.
So provide a library for constructing the string as you go similar to C++'s std::string. string_stream is really just a string builder, nothing more.
Signed-off-by: Brendan Higgins brendanhiggins@google.com Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Reviewed-by: Logan Gunthorpe logang@deltatee.com --- include/kunit/string-stream.h | 51 ++++++++ kunit/Makefile | 3 +- kunit/string-stream.c | 217 ++++++++++++++++++++++++++++++++++ 3 files changed, 270 insertions(+), 1 deletion(-) create mode 100644 include/kunit/string-stream.h create mode 100644 kunit/string-stream.c
diff --git a/include/kunit/string-stream.h b/include/kunit/string-stream.h new file mode 100644 index 0000000000000..fe98a00b75a9c --- /dev/null +++ b/include/kunit/string-stream.h @@ -0,0 +1,51 @@ +/* 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 + */ + +#ifndef _KUNIT_STRING_STREAM_H +#define _KUNIT_STRING_STREAM_H + +#include <linux/spinlock.h> +#include <linux/types.h> +#include <stdarg.h> + +struct string_stream_fragment { + struct kunit *test; + struct list_head node; + char *fragment; +}; + +struct string_stream { + size_t length; + struct list_head fragments; + /* length and fragments are protected by this lock */ + spinlock_t lock; + struct kunit *test; + gfp_t gfp; +}; + +struct kunit; + +struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp); + +int __printf(2, 3) string_stream_add(struct string_stream *stream, + const char *fmt, ...); + +int string_stream_vadd(struct string_stream *stream, + const char *fmt, + va_list args); + +char *string_stream_get_string(struct string_stream *stream); + +int string_stream_append(struct string_stream *stream, + struct string_stream *other); + +bool string_stream_is_empty(struct string_stream *stream); + +int string_stream_destroy(struct string_stream *stream); + +#endif /* _KUNIT_STRING_STREAM_H */ diff --git a/kunit/Makefile b/kunit/Makefile index 5efdc4dea2c08..275b565a0e81f 100644 --- a/kunit/Makefile +++ b/kunit/Makefile @@ -1 +1,2 @@ -obj-$(CONFIG_KUNIT) += test.o +obj-$(CONFIG_KUNIT) += test.o \ + string-stream.o diff --git a/kunit/string-stream.c b/kunit/string-stream.c new file mode 100644 index 0000000000000..e6d17aacca30d --- /dev/null +++ b/kunit/string-stream.c @@ -0,0 +1,217 @@ +// 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/string-stream.h> +#include <kunit/test.h> +#include <linux/list.h> +#include <linux/slab.h> + +struct string_stream_fragment_alloc_context { + struct kunit *test; + int len; + gfp_t gfp; +}; + +static int string_stream_fragment_init(struct kunit_resource *res, + void *context) +{ + struct string_stream_fragment_alloc_context *ctx = context; + struct string_stream_fragment *frag; + + frag = kunit_kzalloc(ctx->test, sizeof(*frag), ctx->gfp); + if (!frag) + return -ENOMEM; + + frag->test = ctx->test; + frag->fragment = kunit_kmalloc(ctx->test, ctx->len, ctx->gfp); + if (!frag->fragment) + return -ENOMEM; + + res->allocation = frag; + + return 0; +} + +static void string_stream_fragment_free(struct kunit_resource *res) +{ + struct string_stream_fragment *frag = res->allocation; + + list_del(&frag->node); + kunit_kfree(frag->test, frag->fragment); + kunit_kfree(frag->test, frag); +} + +static struct string_stream_fragment *alloc_string_stream_fragment( + struct kunit *test, int len, gfp_t gfp) +{ + struct string_stream_fragment_alloc_context context = { + .test = test, + .len = len, + .gfp = gfp + }; + + return kunit_alloc_resource(test, + string_stream_fragment_init, + string_stream_fragment_free, + gfp, + &context); +} + +static int string_stream_fragment_destroy(struct string_stream_fragment *frag) +{ + return kunit_resource_destroy(frag->test, + kunit_resource_instance_match, + string_stream_fragment_free, + 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 (!frag_container) + return -ENOMEM; + + 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(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; +}; + +static int string_stream_init(struct kunit_resource *res, void *context) +{ + struct string_stream *stream; + struct string_stream_alloc_context *ctx = context; + + stream = kunit_kzalloc(ctx->test, sizeof(*stream), ctx->gfp); + if (!stream) + return -ENOMEM; + + res->allocation = stream; + stream->gfp = ctx->gfp; + stream->test = ctx->test; + INIT_LIST_HEAD(&stream->fragments); + spin_lock_init(&stream->lock); + + return 0; +} + +static void string_stream_free(struct kunit_resource *res) +{ + struct string_stream *stream = res->allocation; + + string_stream_clear(stream); +} + +struct string_stream *alloc_string_stream(struct kunit *test, gfp_t gfp) +{ + struct string_stream_alloc_context context = { + .test = test, + .gfp = gfp + }; + + return kunit_alloc_resource(test, + string_stream_init, + string_stream_free, + gfp, + &context); +} + +int string_stream_destroy(struct string_stream *stream) +{ + return kunit_resource_destroy(stream->test, + kunit_resource_instance_match, + string_stream_free, + stream); +}