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 "event-internal.h"
14 
15 typedef struct TraceEventIter {
16     size_t event;
17     size_t group;
18     const char *pattern;
19 } TraceEventIter;
20 
21 
22 /**
23  * trace_event_iter_init:
24  * @iter: the event iterator struct
25  * @pattern: optional pattern to filter events on name
26  *
27  * Initialize the event iterator struct @iter,
28  * optionally using @pattern to filter out events
29  * with non-matching names.
30  */
31 void trace_event_iter_init(TraceEventIter *iter, const char *pattern);
32 
33 /**
34  * trace_event_iter_next:
35  * @iter: the event iterator struct
36  *
37  * Get the next event, if any. When this returns NULL,
38  * the iterator should no longer be used.
39  *
40  * Returns: the next event, or NULL if no more events exist
41  */
42 TraceEvent *trace_event_iter_next(TraceEventIter *iter);
43 
44 
45 /**
46  * trace_event_name:
47  * @id: Event name.
48  *
49  * Search an event by its name.
50  *
51  * Returns: pointer to #TraceEvent or NULL if not found.
52  */
53 TraceEvent *trace_event_name(const char *name);
54 
55 /**
56  * trace_event_is_pattern:
57  *
58  * Whether the given string is an event name pattern.
59  */
60 static bool trace_event_is_pattern(const char *str);
61 
62 
63 /**
64  * trace_event_get_id:
65  *
66  * Get the identifier of an event.
67  */
68 static uint32_t trace_event_get_id(TraceEvent *ev);
69 
70 /**
71  * trace_event_get_vcpu_id:
72  *
73  * Get the per-vCPU identifier of an event.
74  *
75  * Special value #TRACE_VCPU_EVENT_NONE means the event is not vCPU-specific
76  * (does not have the "vcpu" property).
77  */
78 static uint32_t trace_event_get_vcpu_id(TraceEvent *ev);
79 
80 /**
81  * trace_event_is_vcpu:
82  *
83  * Whether this is a per-vCPU event.
84  */
85 static bool trace_event_is_vcpu(TraceEvent *ev);
86 
87 /**
88  * trace_event_get_name:
89  *
90  * Get the name of an event.
91  */
92 static const char * trace_event_get_name(TraceEvent *ev);
93 
94 /**
95  * trace_event_get_state:
96  * @id: Event identifier name.
97  *
98  * Get the tracing state of an event, both static and the QEMU dynamic state.
99  *
100  * If the event has the disabled property, the check will have no performance
101  * impact.
102  */
103 #define trace_event_get_state(id)                       \
104     ((id ##_ENABLED) && trace_event_get_state_dynamic_by_id(id))
105 
106 /**
107  * trace_event_get_state_backends:
108  * @id: Event identifier name.
109  *
110  * Get the tracing state of an event, both static and dynamic state from all
111  * compiled-in backends.
112  *
113  * If the event has the disabled property, the check will have no performance
114  * impact.
115  *
116  * Returns: true if at least one backend has the event enabled and the event
117  * does not have the disabled property.
118  */
119 #define trace_event_get_state_backends(id)              \
120     ((id ##_ENABLED) && id ##_BACKEND_DSTATE())
121 
122 /**
123  * trace_event_get_state_static:
124  * @id: Event identifier.
125  *
126  * Get the static tracing state of an event.
127  *
128  * Use the define 'TRACE_${EVENT_NAME}_ENABLED' for compile-time checks (it will
129  * be set to 1 or 0 according to the presence of the disabled property).
130  */
131 static bool trace_event_get_state_static(TraceEvent *ev);
132 
133 /**
134  * trace_event_get_state_dynamic:
135  *
136  * Get the dynamic tracing state of an event.
137  *
138  * If the event has the 'vcpu' property, gets the OR'ed state of all vCPUs.
139  */
140 static bool trace_event_get_state_dynamic(TraceEvent *ev);
141 
142 /**
143  * trace_event_set_state_dynamic:
144  *
145  * Set the dynamic tracing state of an event.
146  *
147  * If the event has the 'vcpu' property, sets the state on all vCPUs.
148  *
149  * Pre-condition: trace_event_get_state_static(ev) == true
150  */
151 void trace_event_set_state_dynamic(TraceEvent *ev, bool state);
152 
153 /**
154  * trace_event_set_vcpu_state_dynamic:
155  *
156  * Set the dynamic tracing state of an event for the given vCPU.
157  *
158  * Pre-condition: trace_event_get_vcpu_state_static(ev) == true
159  *
160  * Note: Changes for execution-time events with the 'tcg' property will not be
161  *       propagated until the next TB is executed (iff executing in TCG mode).
162  */
163 void trace_event_set_vcpu_state_dynamic(CPUState *vcpu,
164                                         TraceEvent *ev, bool state);
165 
166 
167 
168 /**
169  * trace_init_backends:
170  * @file:   Name of trace output file; may be NULL.
171  *          Corresponds to commandline option "--trace file=...".
172  *
173  * Initialize the tracing backend.
174  *
175  * Returns: Whether the backends could be successfully initialized.
176  */
177 bool trace_init_backends(void);
178 
179 /**
180  * trace_init_file:
181  * @file:   Name of trace output file; may be NULL.
182  *          Corresponds to commandline option "--trace file=...".
183  *
184  * Record the name of the output file for the tracing backend.
185  * Exits if no selected backend does not support specifying the
186  * output file, and a non-NULL file was passed.
187  */
188 void trace_init_file(const char *file);
189 
190 /**
191  * trace_init_vcpu:
192  * @vcpu: Added vCPU.
193  *
194  * Set initial dynamic event state for a hot-plugged vCPU.
195  */
196 void trace_init_vcpu(CPUState *vcpu);
197 
198 /**
199  * trace_fini_vcpu:
200  * @vcpu: Removed vCPU.
201  *
202  * Disable dynamic event state for a hot-unplugged vCPU.
203  */
204 void trace_fini_vcpu(CPUState *vcpu);
205 
206 /**
207  * trace_list_events:
208  *
209  * List all available events.
210  */
211 void trace_list_events(void);
212 
213 /**
214  * trace_enable_events:
215  * @line_buf: A string with a glob pattern of events to be enabled or,
216  *            if the string starts with '-', disabled.
217  *
218  * Enable or disable matching events.
219  */
220 void trace_enable_events(const char *line_buf);
221 
222 /**
223  * Definition of QEMU options describing trace subsystem configuration
224  */
225 extern QemuOptsList qemu_trace_opts;
226 
227 /**
228  * trace_opt_parse:
229  * @optarg: A string argument of --trace command line argument
230  *
231  * Initialize tracing subsystem.
232  *
233  * Returns the filename to save trace to.  It must be freed with g_free().
234  */
235 char *trace_opt_parse(const char *optarg);
236 
237 /**
238  * trace_get_vcpu_event_count:
239  *
240  * Return the number of known vcpu-specific events
241  */
242 uint32_t trace_get_vcpu_event_count(void);
243 
244 
245 #include "control-internal.h"
246 
247 #endif /* TRACE__CONTROL_H */
248