| 1 | /* |
| 2 | * Copyright (C) 2019 Jonathan Rajotte <jonathan.rajotte-julien@efficios.com> |
| 3 | * |
| 4 | * SPDX-License-Identifier: LGPL-2.1-only |
| 5 | * |
| 6 | */ |
| 7 | |
| 8 | #ifndef LTTNG_CONDITION_ON_EVENT_H |
| 9 | #define LTTNG_CONDITION_ON_EVENT_H |
| 10 | |
| 11 | #include <lttng/event-rule/event-rule.h> |
| 12 | #include <lttng/condition/condition.h> |
| 13 | #include <lttng/condition/evaluation.h> |
| 14 | |
| 15 | #ifdef __cplusplus |
| 16 | extern "C" { |
| 17 | #endif |
| 18 | |
| 19 | struct lttng_event_expr; |
| 20 | struct lttng_event_field_value; |
| 21 | |
| 22 | enum lttng_evaluation_on_event_status { |
| 23 | LTTNG_EVALUATION_ON_EVENT_STATUS_NONE = 1, |
| 24 | LTTNG_EVALUATION_ON_EVENT_STATUS_OK = 0, |
| 25 | LTTNG_EVALUATION_ON_EVENT_STATUS_INVALID = -1, |
| 26 | }; |
| 27 | |
| 28 | /** |
| 29 | * On event conditions allows an action to be taken whenever an event matching |
| 30 | * the on event is hit by the tracers. |
| 31 | * |
| 32 | * An on event condition can also specify a payload to be captured at runtime. |
| 33 | * This is done via the capture descriptor. |
| 34 | * |
| 35 | * Note: the dynamic runtime capture of payload is only available for the |
| 36 | * trigger notification subsystem. |
| 37 | */ |
| 38 | |
| 39 | /* |
| 40 | * Create a newly allocated on event condition. |
| 41 | * |
| 42 | * Returns a new condition on success, NULL on failure. This condition must be |
| 43 | * destroyed using lttng_condition_destroy(). |
| 44 | */ |
| 45 | extern struct lttng_condition *lttng_condition_on_event_create( |
| 46 | struct lttng_event_rule *rule); |
| 47 | |
| 48 | /* |
| 49 | * Get the rule property of a on event condition. |
| 50 | * |
| 51 | * The caller does not assume the ownership of the returned rule. The |
| 52 | * rule shall only be used for the duration of the condition's |
| 53 | * lifetime. |
| 54 | * |
| 55 | * Returns LTTNG_CONDITION_STATUS_OK and a pointer to the condition's rule |
| 56 | * on success, LTTNG_CONDITION_STATUS_INVALID if an invalid |
| 57 | * parameter is passed. */ |
| 58 | extern enum lttng_condition_status lttng_condition_on_event_get_rule( |
| 59 | const struct lttng_condition *condition, |
| 60 | const struct lttng_event_rule **rule); |
| 61 | |
| 62 | /** |
| 63 | * lttng_evaluation_on_event_hit are specialised lttng_evaluations which |
| 64 | * allow users to query a number of properties resulting from the evaluation |
| 65 | * of a condition which evaluated to true. |
| 66 | * |
| 67 | * The evaluation of a on event hit yields two different results: |
| 68 | * TEMPORARY - The name of the triggers associated with the condition. |
| 69 | * TODO - The captured event payload if any |
| 70 | */ |
| 71 | |
| 72 | /* |
| 73 | * Get the trigger name property of a on event hit evaluation. |
| 74 | * |
| 75 | * Returns LTTNG_EVALUATION_STATUS_OK on success and a trigger name |
| 76 | * or LTTNG_EVALUATION_STATUS_INVALID if |
| 77 | * an invalid parameter is passed. |
| 78 | */ |
| 79 | extern enum lttng_evaluation_status |
| 80 | lttng_evaluation_on_event_get_trigger_name( |
| 81 | const struct lttng_evaluation *evaluation, |
| 82 | const char **name); |
| 83 | |
| 84 | /* |
| 85 | * Sets `*field_val` to the array event field value of the on event |
| 86 | * condition evaluation `evaluation` which contains its captured values. |
| 87 | * |
| 88 | * Returns: |
| 89 | * |
| 90 | * `LTTNG_EVALUATION_ON_EVENT_STATUS_OK`: |
| 91 | * Success. |
| 92 | * |
| 93 | * `*field_val` is an array event field value with a length of at |
| 94 | * least one. |
| 95 | * |
| 96 | * `LTTNG_EVALUATION_ON_EVENT_STATUS_INVALID`: |
| 97 | * * `evaluation` is `NULL`. |
| 98 | * * The type of the condition of `evaluation` is not |
| 99 | * `LTTNG_CONDITION_TYPE_ON_EVENT`. |
| 100 | * * `field_val` is `NULL`. |
| 101 | * |
| 102 | * `LTTNG_EVALUATION_ON_EVENT_STATUS_NONE`: |
| 103 | * * The condition of `evaluation` has no capture descriptors. |
| 104 | */ |
| 105 | extern enum lttng_evaluation_on_event_status |
| 106 | lttng_evaluation_on_event_get_captured_values( |
| 107 | const struct lttng_evaluation *evaluation, |
| 108 | const struct lttng_event_field_value **field_val); |
| 109 | |
| 110 | /* |
| 111 | * Appends (transfering the ownership) the capture descriptor `expr` to |
| 112 | * the on event condition `condition`. |
| 113 | * |
| 114 | * Returns: |
| 115 | * |
| 116 | * `LTTNG_CONDITION_STATUS_OK`: |
| 117 | * Success. |
| 118 | * |
| 119 | * `LTTNG_CONDITION_STATUS_ERROR`: |
| 120 | * Memory error. |
| 121 | * |
| 122 | * `LTTNG_CONDITION_STATUS_INVALID`: |
| 123 | * * `condition` is `NULL`. |
| 124 | * * The type of `condition` is not |
| 125 | * `LTTNG_CONDITION_TYPE_ON_EVENT`. |
| 126 | * * `expr` is `NULL`. |
| 127 | * * `expr` is not a locator expression, that is, its type is not |
| 128 | * one of: |
| 129 | * |
| 130 | * * `LTTNG_EVENT_EXPR_TYPE_EVENT_PAYLOAD_FIELD` |
| 131 | * * `LTTNG_EVENT_EXPR_TYPE_CHANNEL_CONTEXT_FIELD` |
| 132 | * * `LTTNG_EVENT_EXPR_TYPE_APP_SPECIFIC_CONTEXT_FIELD` |
| 133 | * * `LTTNG_EVENT_EXPR_TYPE_ARRAY_FIELD_ELEMENT` |
| 134 | * |
| 135 | * `LTTNG_CONDITION_STATUS_UNSUPPORTED`: |
| 136 | * * The associated event-rule does not support runtime capture. |
| 137 | */ |
| 138 | extern enum lttng_condition_status |
| 139 | lttng_condition_on_event_append_capture_descriptor( |
| 140 | struct lttng_condition *condition, |
| 141 | struct lttng_event_expr *expr); |
| 142 | |
| 143 | /* |
| 144 | * Sets `*count` to the number of capture descriptors in the on event |
| 145 | * condition `condition`. |
| 146 | * |
| 147 | * Returns: |
| 148 | * |
| 149 | * `LTTNG_CONDITION_STATUS_OK`: |
| 150 | * Success. |
| 151 | * |
| 152 | * `LTTNG_CONDITION_STATUS_INVALID`: |
| 153 | * * `condition` is `NULL`. |
| 154 | * * The type of `condition` is not |
| 155 | * `LTTNG_CONDITION_TYPE_ON_EVENT`. |
| 156 | * * `count` is `NULL`. |
| 157 | */ |
| 158 | extern enum lttng_condition_status |
| 159 | lttng_condition_on_event_get_capture_descriptor_count( |
| 160 | const struct lttng_condition *condition, unsigned int *count); |
| 161 | |
| 162 | /* |
| 163 | * Returns the capture descriptor (borrowed) of the on event condition |
| 164 | * `condition` at the index `index`, or `NULL` if: |
| 165 | * |
| 166 | * * `condition` is `NULL`. |
| 167 | * * The type of `condition` is not |
| 168 | * `LTTNG_CONDITION_TYPE_ON_EVENT`. |
| 169 | * * `index` is greater than or equal to the number of capture |
| 170 | * descriptors in `condition` (as returned by |
| 171 | * lttng_condition_on_event_get_capture_descriptor_count()). |
| 172 | */ |
| 173 | extern const struct lttng_event_expr * |
| 174 | lttng_condition_on_event_get_capture_descriptor_at_index( |
| 175 | const struct lttng_condition *condition, unsigned int index); |
| 176 | |
| 177 | #ifdef __cplusplus |
| 178 | } |
| 179 | #endif |
| 180 | |
| 181 | #endif /* LTTNG_CONDITION_ON_EVENT_H */ |