| 1 | /* |
| 2 | * SPDX-License-Identifier: MIT |
| 3 | * |
| 4 | * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
| 5 | * |
| 6 | * The context provider feature is part of the ABI and used by the Java jni |
| 7 | * interface. This header should be moved to the public header directory once |
| 8 | * some test code and documentation is written. |
| 9 | */ |
| 10 | |
| 11 | #ifndef _LTTNG_UST_CONTEXT_PROVIDER_H |
| 12 | #define _LTTNG_UST_CONTEXT_PROVIDER_H |
| 13 | |
| 14 | #include <stddef.h> |
| 15 | #include <lttng/ust-events.h> |
| 16 | |
| 17 | #include "common/dynamic-type.h" |
| 18 | |
| 19 | struct lttng_ust_registered_context_provider; |
| 20 | struct lttng_ust_probe_ctx; |
| 21 | |
| 22 | /* |
| 23 | * Context value |
| 24 | * |
| 25 | * IMPORTANT: this structure is part of the ABI between the probe and |
| 26 | * UST. Additional selectors may be added in the future, mapping to new |
| 27 | * union fields, which means the overall size of this structure may |
| 28 | * increase. This means this structure should never be nested within a |
| 29 | * public structure interface, nor embedded in an array. |
| 30 | */ |
| 31 | |
| 32 | struct lttng_ust_ctx_value { |
| 33 | enum lttng_ust_dynamic_type sel; /* Type selector */ |
| 34 | union { |
| 35 | int64_t s64; |
| 36 | uint64_t u64; |
| 37 | const char *str; |
| 38 | double d; |
| 39 | } u; |
| 40 | }; |
| 41 | |
| 42 | /* |
| 43 | * Context provider |
| 44 | * |
| 45 | * IMPORTANT: this structure is part of the ABI between the probe and |
| 46 | * UST. Fields need to be only added at the end, never reordered, never |
| 47 | * removed. |
| 48 | * |
| 49 | * The field @struct_size should be used to determine the size of the |
| 50 | * structure. It should be queried before using additional fields added |
| 51 | * at the end of the structure. |
| 52 | */ |
| 53 | |
| 54 | struct lttng_ust_context_provider { |
| 55 | uint32_t struct_size; |
| 56 | |
| 57 | const char *name; |
| 58 | size_t (*get_size)(void *priv, struct lttng_ust_probe_ctx *probe_ctx, |
| 59 | size_t offset); |
| 60 | void (*record)(void *priv, struct lttng_ust_probe_ctx *probe_ctx, |
| 61 | struct lttng_ust_ring_buffer_ctx *ctx, |
| 62 | struct lttng_ust_channel_buffer *chan); |
| 63 | void (*get_value)(void *priv, struct lttng_ust_probe_ctx *probe_ctx, |
| 64 | struct lttng_ust_ctx_value *value); |
| 65 | void *priv; |
| 66 | |
| 67 | /* End of base ABI. Fields below should be used after checking struct_size. */ |
| 68 | }; |
| 69 | |
| 70 | /* |
| 71 | * Application context callback private data |
| 72 | * |
| 73 | * IMPORTANT: this structure is part of the ABI between the probe and |
| 74 | * UST. Fields need to be only added at the end, never reordered, never |
| 75 | * removed. |
| 76 | * |
| 77 | * The field @struct_size should be used to determine the size of the |
| 78 | * structure. It should be queried before using additional fields added |
| 79 | * at the end of the structure. |
| 80 | */ |
| 81 | |
| 82 | struct lttng_ust_app_context { |
| 83 | uint32_t struct_size; |
| 84 | |
| 85 | struct lttng_ust_event_field *event_field; |
| 86 | char *ctx_name; |
| 87 | |
| 88 | /* End of base ABI. Fields below should be used after checking struct_size. */ |
| 89 | }; |
| 90 | |
| 91 | /* |
| 92 | * Returns an opaque pointer on success, which must be passed to |
| 93 | * lttng_ust_context_provider_unregister for unregistration. Returns |
| 94 | * NULL on error. |
| 95 | */ |
| 96 | struct lttng_ust_registered_context_provider *lttng_ust_context_provider_register(struct lttng_ust_context_provider *provider); |
| 97 | |
| 98 | void lttng_ust_context_provider_unregister(struct lttng_ust_registered_context_provider *reg_provider); |
| 99 | |
| 100 | #endif /* _LTTNG_UST_CONTEXT_PROVIDER_H */ |