On Thu, 7 Jan 2021 18:15:44 +0200
"Yordan Karadzhov (VMware)" <y.karadz@xxxxxxxxx> wrote:
> When we implement a KernelShark plugins, we often need a way to define
> a structure that can hold context data that is visible only inside the
> plugin and that has specific values for each data stream. The tricky
> part here is that the total number of data streams and the IDs of the
> active streams are dynamic quantities that can change as the user adds
> or removes data streams. The macro defines an interface of functions
> that will be useful for the plugin developer, helping to directly use
> context objects, without caring for the complications due to the dynamic
> configuration of active data streams.
You some how lost your signed off by.
-- Steve
> ---
> src/libkshark-plugin.h | 41 +++++++++++++++++++++++++++++++++++++++
> tests/libkshark-tests.cpp | 32 ++++++++++++++++++++++++++++++
> 2 files changed, 73 insertions(+)
>
> diff --git a/src/libkshark-plugin.h b/src/libkshark-plugin.h
> index 4104357..c62086f 100644
> --- a/src/libkshark-plugin.h
> +++ b/src/libkshark-plugin.h
> @@ -363,6 +363,47 @@ int kshark_handle_all_dpis(struct kshark_data_stream *stream,
> __ok; \
> }) \
>
> +/** General purpose macro defining methods for adding plugin context. */
> +#define KS_DEFINE_PLUGIN_CONTEXT(type) \
> +static type **__context_handler; \
> +static ssize_t __n_streams = -1; \
> +static inline type *__init(int sd) \
> +{ \
> + type *obj; \
> + if (__n_streams < 0 && sd < KS_DEFAULT_NUM_STREAMS) { \
> + __context_handler = \
> + (type **) calloc(KS_DEFAULT_NUM_STREAMS, \
> + sizeof(*__context_handler)); \
> + if (!__context_handler) \
> + return NULL; \
> + __n_streams = KS_DEFAULT_NUM_STREAMS; \
> + } else if (sd >= __n_streams) { \
> + if (!KS_DOUBLE_SIZE(__context_handler, \
> + __n_streams)) \
> + return NULL; \
> + } \
> + assert(__context_handler[sd] == NULL); \
> + obj = (type *) calloc(1, sizeof(*obj)); \
> + __context_handler[sd] = obj; \
> + return obj; \
> +} \
> +static inline void __close(int sd) \
> +{ \
> + if (sd < 0) { \
> + free(__context_handler); \
> + __n_streams = -1; \
> + return; \
> + } \
> + free(__context_handler[sd]); \
> + __context_handler[sd] = NULL; \
> +} \
> +static inline type *__get_context(int sd) \
> +{ \
> + if (sd < 0 || sd >= __n_streams) \
> + return NULL; \
> + return __context_handler[sd]; \
> +} \
> +
> #ifdef __cplusplus
> }
> #endif // __cplusplus
> diff --git a/tests/libkshark-tests.cpp b/tests/libkshark-tests.cpp
> index 8a5dcf1..780a3fa 100644
> --- a/tests/libkshark-tests.cpp
> +++ b/tests/libkshark-tests.cpp
> @@ -10,6 +10,7 @@
>
> // KernelShark
> #include "libkshark.h"
> +#include "libkshark-plugin.h"
>
> #define N_TEST_STREAMS 1000
>
> @@ -103,3 +104,34 @@ BOOST_AUTO_TEST_CASE(fill_data_container)
>
> kshark_free_data_container(data);
> }
> +
> +struct test_context {
> + int a;
> + char b;
> +};
> +
> +KS_DEFINE_PLUGIN_CONTEXT(struct test_context);
> +
> +BOOST_AUTO_TEST_CASE(init_close_plugin)
> +{
> + struct test_context *ctx;
> + int i;
> +
> + for (i = 0; i < N_TEST_STREAMS; ++i) {
> + ctx = __init(i);
> + ctx->a = i * 10;
> + ctx->b = 'z';
> + }
> +
> + for (i = 0; i < N_TEST_STREAMS; ++i) {
> + ctx = __get_context(i);
> + BOOST_REQUIRE(ctx != NULL);
> + BOOST_CHECK_EQUAL(ctx->a, i * 10);
> + BOOST_CHECK_EQUAL(ctx->b, 'z');
> +
> + __close(i);
> + BOOST_REQUIRE(__get_context(i) == NULL);
> + }
> +
> + __close(-1);
> +}
|