trace/control.h

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2016 Lluís Vilanova <vilanova@ac.upc.edu>
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  */
   9
  10 #ifndef TRACE__CONTROL_H
  11 #define TRACE__CONTROL_H
  12
  13 #include "qemu-common.h"
  14 #include "trace/generated-events.h"
  15
  16
  17 /**
  18  * TraceEventID:
  19  *
  20  * Unique tracing event identifier.
  21  *
  22  * These are named as 'TRACE_${EVENT_NAME}'.
  23  *
  24  * See also: "trace/generated-events.h"
  25  */
  26 enum TraceEventID;
  27
  28 /**
  29  * trace_event_id:
  30  * @id: Event identifier.
  31  *
  32  * Get an event by its identifier.
  33  *
  34  * This routine has a constant cost, as opposed to trace_event_name and
  35  * trace_event_pattern.
  36  *
  37  * Pre-conditions: The identifier is valid.
  38  *
  39  * Returns: pointer to #TraceEvent.
  40  *
  41  */
  42 static TraceEvent *trace_event_id(TraceEventID id);
  43
  44 /**
  45  * trace_event_name:
  46  * @id: Event name.
  47  *
  48  * Search an event by its name.
  49  *
  50  * Returns: pointer to #TraceEvent or NULL if not found.
  51  */
  52 TraceEvent *trace_event_name(const char *name);
  53
  54 /**
  55  * trace_event_pattern:
  56  * @pat: Event name pattern.
  57  * @ev: Event to start searching from (not included).
  58  *
  59  * Get all events with a given name pattern.
  60  *
  61  * Returns: pointer to #TraceEvent or NULL if not found.
  62  */
  63 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev);
  64
  65 /**
  66  * trace_event_is_pattern:
  67  *
  68  * Whether the given string is an event name pattern.
  69  */
  70 static bool trace_event_is_pattern(const char *str);
  71
  72 /**
  73  * trace_event_count:
  74  *
  75  * Return the number of events.
  76  */
  77 static TraceEventID trace_event_count(void);
  78
  79
  80
  81 /**
  82  * trace_event_get_id:
  83  *
  84  * Get the identifier of an event.
  85  */
  86 static TraceEventID trace_event_get_id(TraceEvent *ev);
  87
  88 /**
  89  * trace_event_get_name:
  90  *
  91  * Get the name of an event.
  92  */
  93 static const char * trace_event_get_name(TraceEvent *ev);
  94
  95 /**
  96  * trace_event_get_state:
  97  * @id: Event identifier.
  98  *
  99  * Get the tracing state of an event (both static and dynamic).
 100  *
 101  * If the event has the disabled property, the check will have no performance
 102  * impact.
 103  *
 104  * As a down side, you must always use an immediate #TraceEventID value.
 105  */
 106 #define trace_event_get_state(id)                       \
 107     ((id ##_ENABLED) && trace_event_get_state_dynamic_by_id(id))
 108
 109 /**
 110  * trace_event_get_state_static:
 111  * @id: Event identifier.
 112  *
 113  * Get the static tracing state of an event.
 114  *
 115  * Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
 116  * be set to 1 or 0 according to the presence of the disabled property).
 117  */
 118 static bool trace_event_get_state_static(TraceEvent *ev);
 119
 120 /**
 121  * trace_event_get_state_dynamic:
 122  *
 123  * Get the dynamic tracing state of an event.
 124  */
 125 static bool trace_event_get_state_dynamic(TraceEvent *ev);
 126
 127 /**
 128  * trace_event_set_state:
 129  *
 130  * Set the tracing state of an event (only if possible).
 131  */
 132 #define trace_event_set_state(id, state)                \
 133     do {                                                \
 134         if ((id ##_ENABLED)) {                          \
 135             TraceEvent *_e = trace_event_id(id);        \
 136             trace_event_set_state_dynamic(_e, state);   \
 137         }                                               \
 138     } while (0)
 139
 140 /**
 141  * trace_event_set_state_dynamic:
 142  *
 143  * Set the dynamic tracing state of an event.
 144  *
 145  * Pre-condition: trace_event_get_state_static(ev) == true
 146  */
 147 static void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
 148
 149
 150
 151 /**
 152  * trace_init_backends:
 153  * @file:   Name of trace output file; may be NULL.
 154  *          Corresponds to commandline option "-trace file=...".
 155  *
 156  * Initialize the tracing backend.
 157  *
 158  * Returns: Whether the backends could be successfully initialized.
 159  */
 160 bool trace_init_backends(void);
 161
 162 /**
 163  * trace_init_file:
 164  * @file:   Name of trace output file; may be NULL.
 165  *          Corresponds to commandline option "-trace file=...".
 166  *
 167  * Record the name of the output file for the tracing backend.
 168  * Exits if no selected backend does not support specifying the
 169  * output file, and a non-NULL file was passed.
 170  */
 171 void trace_init_file(const char *file);
 172
 173 /**
 174  * trace_list_events:
 175  *
 176  * List all available events.
 177  */
 178 void trace_list_events(void);
 179
 180 /**
 181  * trace_enable_events:
 182  * @line_buf: A string with a glob pattern of events to be enabled or,
 183  *            if the string starts with '-', disabled.
 184  *
 185  * Enable or disable matching events.
 186  */
 187 void trace_enable_events(const char *line_buf);
 188
 189 /**
 190  * Definition of QEMU options describing trace subsystem configuration
 191  */
 192 extern QemuOptsList qemu_trace_opts;
 193
 194 /**
 195  * trace_opt_parse:
 196  * @optarg: A string argument of --trace command line argument
 197  *
 198  * Initialize tracing subsystem.
 199  *
 200  * Returns the filename to save trace to.  It must be freed with g_free().
 201  */
 202 char *trace_opt_parse(const char *optarg);
 203
 204 #include "trace/control-internal.h"
 205
 206 #endif  /* TRACE__CONTROL_H */