| Message ID | 20210106161120.119085-4-y.karadz@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | kernel-shark: Visualization plugin tools | expand |
On Wed, 6 Jan 2021 18:11:17 +0200 "Yordan Karadzhov (VMware)" <y.karadz@gmail.com> 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. > --- > src/libkshark-plugin.h | 43 +++++++++++++++++++++++++++++++++++++++ > tests/libkshark-tests.cpp | 32 +++++++++++++++++++++++++++++ > 2 files changed, 75 insertions(+) > > diff --git a/src/libkshark-plugin.h b/src/libkshark-plugin.h > index f3c724f..e58d658 100644 > --- a/src/libkshark-plugin.h > +++ b/src/libkshark-plugin.h > @@ -360,6 +360,49 @@ int kshark_handle_all_dpis(struct kshark_data_stream *stream, > } \ > } \ > > +/** General purpose macro defining methods for adding plugin context. */ > +#define KS_DEFINE_PLUGIN_CONTEXT(type) \ When macros like this are done in Linux, it is common to add a "prefix" argument, and name all the variables and functions created by it with that prefix. #define KS_DEFINE_PLUGIN_CONTEXT(prefix, type) \ static type **prefix##_context_handler; \ [..] static inline type *prefix##_init(int sd) \ [..] This would allow this macro to be used more than once in a file. It's up to you if you want to do it that way. -- Steve > +static type **__context_handler; \ > +static ssize_t __n_streams = -1; \ > +static bool ok; \ > +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) { \ > + KS_DOUBLE_SIZE(type *, __context_handler, \ > + &__n_streams, &ok) \ > + if (!ok) \ > + 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/src/libkshark-plugin.h b/src/libkshark-plugin.h index f3c724f..e58d658 100644 --- a/src/libkshark-plugin.h +++ b/src/libkshark-plugin.h @@ -360,6 +360,49 @@ int kshark_handle_all_dpis(struct kshark_data_stream *stream, } \ } \ +/** 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 bool ok; \ +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) { \ + KS_DOUBLE_SIZE(type *, __context_handler, \ + &__n_streams, &ok) \ + if (!ok) \ + 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 06fdf62..4990cdb 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 @@ -80,3 +81,34 @@ 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); +}