include/side/abi/visitor.h

   1 // SPDX-License-Identifier: MIT
   2 /*
   3  * Copyright 2022-2023 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   4  */
   5
   6 #ifndef SIDE_ABI_VISITOR_H
   7 #define SIDE_ABI_VISITOR_H
   8
   9 #include <stdint.h>
  10 #include <side/macros.h>
  11 #include <side/endian.h>
  12
  13 /*
  14  * SIDE ABI for visitor pattern.
  15  *
  16  * The visitor pattern is a double-dispatch visitor. Changing this ABI
  17  * is a breaking ABI change.
  18  *
  19  * This ABI is a contract between the instrumented application and
  20  * user-space tracers. Kernel tracers are not expected to interact with
  21  * visitors directly: a proxy in libside should execute visitors to
  22  * convert their output to other types which can be read by the kernel
  23  * tracers.
  24  */
  25
  26 struct side_arg;
  27 struct side_arg_dynamic_field;
  28 struct side_tracer_visitor_ctx;
  29 struct side_tracer_dynamic_struct_visitor_ctx;
  30
  31
  32 typedef enum side_visitor_status (*side_write_elem_func)(
  33                 const struct side_tracer_visitor_ctx *tracer_ctx,
  34                 const struct side_arg *elem);
  35 typedef enum side_visitor_status (*side_visitor_func)(
  36                 const struct side_tracer_visitor_ctx *tracer_ctx,
  37                 void *app_ctx);
  38
  39 struct side_tracer_visitor_ctx {
  40         side_write_elem_func write_elem;
  41         void *priv;             /* Private tracer context. */
  42 } SIDE_PACKED;
  43
  44 typedef enum side_visitor_status (*side_write_field_func)(
  45                 const struct side_tracer_dynamic_struct_visitor_ctx *tracer_ctx,
  46                 const struct side_arg_dynamic_field *dynamic_field);
  47 typedef enum side_visitor_status (*side_dynamic_struct_visitor_func)(
  48                 const struct side_tracer_dynamic_struct_visitor_ctx *tracer_ctx,
  49                 void *app_ctx);
  50
  51 struct side_tracer_dynamic_struct_visitor_ctx {
  52         side_write_field_func write_field;
  53         void *priv;             /* Private tracer context. */
  54 } SIDE_PACKED;
  55
  56 #endif /* SIDE_ABI_VISITOR_H */