Merge remote-tracking branch 'remotes/armbru/tags/pull-misc-2021-07-27' into staging
[qemu.git] / trace / control.c
1 /*
2 * Interface for configuring and controlling the state of tracing events.
3 *
4 * Copyright (C) 2011-2016 LluĂ­s 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 #include "qemu/osdep.h"
11 #include "trace/control.h"
12 #include "qemu/help_option.h"
13 #include "qemu/option.h"
14 #ifdef CONFIG_TRACE_SIMPLE
15 #include "trace/simple.h"
16 #endif
17 #ifdef CONFIG_TRACE_FTRACE
18 #include "trace/ftrace.h"
19 #endif
20 #ifdef CONFIG_TRACE_LOG
21 #include "qemu/log.h"
22 #endif
23 #ifdef CONFIG_TRACE_SYSLOG
24 #include <syslog.h>
25 #endif
26 #include "qapi/error.h"
27 #include "qemu/error-report.h"
28 #include "qemu/config-file.h"
29 #include "monitor/monitor.h"
30 #include "trace/trace-root.h"
31
32 int trace_events_enabled_count;
33
34 typedef struct TraceEventGroup {
35 TraceEvent **events;
36 } TraceEventGroup;
37
38 static TraceEventGroup *event_groups;
39 static size_t nevent_groups;
40 static uint32_t next_id;
41 static uint32_t next_vcpu_id;
42 static bool init_trace_on_startup;
43 static char *trace_opts_file;
44
45 QemuOptsList qemu_trace_opts = {
46 .name = "trace",
47 .implied_opt_name = "enable",
48 .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
49 .desc = {
50 {
51 .name = "enable",
52 .type = QEMU_OPT_STRING,
53 },
54 {
55 .name = "events",
56 .type = QEMU_OPT_STRING,
57 },{
58 .name = "file",
59 .type = QEMU_OPT_STRING,
60 },
61 { /* end of list */ }
62 },
63 };
64
65
66 void trace_event_register_group(TraceEvent **events)
67 {
68 size_t i;
69 for (i = 0; events[i] != NULL; i++) {
70 events[i]->id = next_id++;
71 if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
72 continue;
73 }
74
75 if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
76 events[i]->vcpu_id = next_vcpu_id++;
77 } else {
78 warn_report("too many vcpu trace events; dropping '%s'",
79 events[i]->name);
80 }
81 }
82 event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
83 event_groups[nevent_groups].events = events;
84 nevent_groups++;
85 }
86
87
88 TraceEvent *trace_event_name(const char *name)
89 {
90 assert(name != NULL);
91
92 TraceEventIter iter;
93 TraceEvent *ev;
94 trace_event_iter_init(&iter, NULL);
95 while ((ev = trace_event_iter_next(&iter)) != NULL) {
96 if (strcmp(trace_event_get_name(ev), name) == 0) {
97 return ev;
98 }
99 }
100 return NULL;
101 }
102
103 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
104 {
105 iter->event = 0;
106 iter->group = 0;
107 iter->pattern = pattern;
108 }
109
110 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
111 {
112 while (iter->group < nevent_groups &&
113 event_groups[iter->group].events[iter->event] != NULL) {
114 TraceEvent *ev = event_groups[iter->group].events[iter->event];
115 iter->event++;
116 if (event_groups[iter->group].events[iter->event] == NULL) {
117 iter->event = 0;
118 iter->group++;
119 }
120 if (!iter->pattern ||
121 g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
122 return ev;
123 }
124 }
125
126 return NULL;
127 }
128
129 void trace_list_events(FILE *f)
130 {
131 TraceEventIter iter;
132 TraceEvent *ev;
133 trace_event_iter_init(&iter, NULL);
134 while ((ev = trace_event_iter_next(&iter)) != NULL) {
135 fprintf(f, "%s\n", trace_event_get_name(ev));
136 }
137 #ifdef CONFIG_TRACE_DTRACE
138 fprintf(f, "This list of names of trace points may be incomplete "
139 "when using the DTrace/SystemTap backends.\n"
140 "Run 'qemu-trace-stap list %s' to print the full list.\n",
141 error_get_progname());
142 #endif
143 }
144
145 static void do_trace_enable_events(const char *line_buf)
146 {
147 const bool enable = ('-' != line_buf[0]);
148 const char *line_ptr = enable ? line_buf : line_buf + 1;
149 TraceEventIter iter;
150 TraceEvent *ev;
151 bool is_pattern = trace_event_is_pattern(line_ptr);
152
153 trace_event_iter_init(&iter, line_ptr);
154 while ((ev = trace_event_iter_next(&iter)) != NULL) {
155 if (!trace_event_get_state_static(ev)) {
156 if (!is_pattern) {
157 warn_report("trace event '%s' is not traceable",
158 line_ptr);
159 return;
160 }
161 continue;
162 }
163
164 /* start tracing */
165 trace_event_set_state_dynamic(ev, enable);
166 if (!is_pattern) {
167 return;
168 }
169 }
170
171 if (!is_pattern) {
172 warn_report("trace event '%s' does not exist",
173 line_ptr);
174 }
175 }
176
177 void trace_enable_events(const char *line_buf)
178 {
179 if (is_help_option(line_buf)) {
180 trace_list_events(stdout);
181 if (monitor_cur() == NULL) {
182 exit(0);
183 }
184 } else {
185 do_trace_enable_events(line_buf);
186 }
187 }
188
189 static void trace_init_events(const char *fname)
190 {
191 Location loc;
192 FILE *fp;
193 char line_buf[1024];
194 size_t line_idx = 0;
195
196 if (fname == NULL) {
197 return;
198 }
199
200 loc_push_none(&loc);
201 loc_set_file(fname, 0);
202 fp = fopen(fname, "r");
203 if (!fp) {
204 error_report("%s", strerror(errno));
205 exit(1);
206 }
207 while (fgets(line_buf, sizeof(line_buf), fp)) {
208 loc_set_file(fname, ++line_idx);
209 size_t len = strlen(line_buf);
210 if (len > 1) { /* skip empty lines */
211 line_buf[len - 1] = '\0';
212 if ('#' == line_buf[0]) { /* skip commented lines */
213 continue;
214 }
215 trace_enable_events(line_buf);
216 }
217 }
218 if (fclose(fp) != 0) {
219 loc_set_file(fname, 0);
220 error_report("%s", strerror(errno));
221 exit(1);
222 }
223 loc_pop(&loc);
224 }
225
226 void trace_init_file(void)
227 {
228 #ifdef CONFIG_TRACE_SIMPLE
229 st_set_trace_file(trace_opts_file);
230 if (init_trace_on_startup) {
231 st_set_trace_file_enabled(true);
232 }
233 #elif defined CONFIG_TRACE_LOG
234 /*
235 * If both the simple and the log backends are enabled, "--trace file"
236 * only applies to the simple backend; use "-D" for the log
237 * backend. However we should only override -D if we actually have
238 * something to override it with.
239 */
240 if (trace_opts_file) {
241 qemu_set_log_filename(trace_opts_file, &error_fatal);
242 }
243 #else
244 if (trace_opts_file) {
245 fprintf(stderr, "error: --trace file=...: "
246 "option not supported by the selected tracing backends\n");
247 exit(1);
248 }
249 #endif
250 }
251
252 void trace_fini_vcpu(CPUState *vcpu)
253 {
254 TraceEventIter iter;
255 TraceEvent *ev;
256
257 trace_guest_cpu_exit(vcpu);
258
259 trace_event_iter_init(&iter, NULL);
260 while ((ev = trace_event_iter_next(&iter)) != NULL) {
261 if (trace_event_is_vcpu(ev) &&
262 trace_event_get_state_static(ev) &&
263 trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
264 /* must disable to affect the global counter */
265 trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
266 }
267 }
268 }
269
270 bool trace_init_backends(void)
271 {
272 #ifdef CONFIG_TRACE_SIMPLE
273 if (!st_init()) {
274 fprintf(stderr, "failed to initialize simple tracing backend.\n");
275 return false;
276 }
277 #endif
278
279 #ifdef CONFIG_TRACE_FTRACE
280 if (!ftrace_init()) {
281 fprintf(stderr, "failed to initialize ftrace backend.\n");
282 return false;
283 }
284 #endif
285
286 #ifdef CONFIG_TRACE_SYSLOG
287 openlog(NULL, LOG_PID, LOG_DAEMON);
288 #endif
289
290 return true;
291 }
292
293 void trace_opt_parse(const char *optarg)
294 {
295 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
296 optarg, true);
297 if (!opts) {
298 exit(1);
299 }
300 if (qemu_opt_get(opts, "enable")) {
301 trace_enable_events(qemu_opt_get(opts, "enable"));
302 }
303 trace_init_events(qemu_opt_get(opts, "events"));
304 init_trace_on_startup = true;
305 g_free(trace_opts_file);
306 trace_opts_file = g_strdup(qemu_opt_get(opts, "file"));
307 qemu_opts_del(opts);
308 }
309
310 uint32_t trace_get_vcpu_event_count(void)
311 {
312 return next_vcpu_id;
313 }