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 #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-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
43 QemuOptsList qemu_trace_opts = {
44 .name = "trace",
45 .implied_opt_name = "enable",
46 .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
47 .desc = {
48 {
49 .name = "enable",
50 .type = QEMU_OPT_STRING,
51 },
52 {
53 .name = "events",
54 .type = QEMU_OPT_STRING,
55 },{
56 .name = "file",
57 .type = QEMU_OPT_STRING,
58 },
59 { /* end of list */ }
60 },
61 };
62
63
trace_event_register_group(TraceEvent ** events)64 void trace_event_register_group(TraceEvent **events)
65 {
66 size_t i;
67 for (i = 0; events[i] != NULL; i++) {
68 events[i]->id = next_id++;
69 if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
70 continue;
71 }
72
73 if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
74 events[i]->vcpu_id = next_vcpu_id++;
75 } else {
76 warn_report("too many vcpu trace events; dropping '%s'",
77 events[i]->name);
78 }
79 }
80 event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
81 event_groups[nevent_groups].events = events;
82 nevent_groups++;
83 }
84
85
trace_event_name(const char * name)86 TraceEvent *trace_event_name(const char *name)
87 {
88 assert(name != NULL);
89
90 TraceEventIter iter;
91 TraceEvent *ev;
92 trace_event_iter_init(&iter, NULL);
93 while ((ev = trace_event_iter_next(&iter)) != NULL) {
94 if (strcmp(trace_event_get_name(ev), name) == 0) {
95 return ev;
96 }
97 }
98 return NULL;
99 }
100
pattern_glob(const char * pat,const char * ev)101 static bool pattern_glob(const char *pat, const char *ev)
102 {
103 while (*pat != '\0' && *ev != '\0') {
104 if (*pat == *ev) {
105 pat++;
106 ev++;
107 }
108 else if (*pat == '*') {
109 if (pattern_glob(pat, ev+1)) {
110 return true;
111 } else if (pattern_glob(pat+1, ev)) {
112 return true;
113 } else {
114 return false;
115 }
116 } else {
117 return false;
118 }
119 }
120
121 while (*pat == '*') {
122 pat++;
123 }
124
125 if (*pat == '\0' && *ev == '\0') {
126 return true;
127 } else {
128 return false;
129 }
130 }
131
132
trace_event_iter_init(TraceEventIter * iter,const char * pattern)133 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
134 {
135 iter->event = 0;
136 iter->group = 0;
137 iter->pattern = pattern;
138 }
139
trace_event_iter_next(TraceEventIter * iter)140 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
141 {
142 while (iter->group < nevent_groups &&
143 event_groups[iter->group].events[iter->event] != NULL) {
144 TraceEvent *ev = event_groups[iter->group].events[iter->event];
145 iter->event++;
146 if (event_groups[iter->group].events[iter->event] == NULL) {
147 iter->event = 0;
148 iter->group++;
149 }
150 if (!iter->pattern ||
151 pattern_glob(iter->pattern,
152 trace_event_get_name(ev))) {
153 return ev;
154 }
155 }
156
157 return NULL;
158 }
159
trace_list_events(void)160 void trace_list_events(void)
161 {
162 TraceEventIter iter;
163 TraceEvent *ev;
164 trace_event_iter_init(&iter, NULL);
165 while ((ev = trace_event_iter_next(&iter)) != NULL) {
166 fprintf(stderr, "%s\n", trace_event_get_name(ev));
167 }
168 #ifdef CONFIG_TRACE_DTRACE
169 fprintf(stderr, "This list of names of trace points may be incomplete "
170 "when using the DTrace/SystemTap backends.\n"
171 "Run 'qemu-trace-stap list %s' to print the full list.\n",
172 error_get_progname());
173 #endif
174 }
175
do_trace_enable_events(const char * line_buf)176 static void do_trace_enable_events(const char *line_buf)
177 {
178 const bool enable = ('-' != line_buf[0]);
179 const char *line_ptr = enable ? line_buf : line_buf + 1;
180 TraceEventIter iter;
181 TraceEvent *ev;
182 bool is_pattern = trace_event_is_pattern(line_ptr);
183
184 trace_event_iter_init(&iter, line_ptr);
185 while ((ev = trace_event_iter_next(&iter)) != NULL) {
186 if (!trace_event_get_state_static(ev)) {
187 if (!is_pattern) {
188 warn_report("trace event '%s' is not traceable",
189 line_ptr);
190 return;
191 }
192 continue;
193 }
194
195 /* start tracing */
196 trace_event_set_state_dynamic(ev, enable);
197 if (!is_pattern) {
198 return;
199 }
200 }
201
202 if (!is_pattern) {
203 warn_report("trace event '%s' does not exist",
204 line_ptr);
205 }
206 }
207
trace_enable_events(const char * line_buf)208 void trace_enable_events(const char *line_buf)
209 {
210 if (is_help_option(line_buf)) {
211 trace_list_events();
212 if (cur_mon == NULL) {
213 exit(0);
214 }
215 } else {
216 do_trace_enable_events(line_buf);
217 }
218 }
219
trace_init_events(const char * fname)220 static void trace_init_events(const char *fname)
221 {
222 Location loc;
223 FILE *fp;
224 char line_buf[1024];
225 size_t line_idx = 0;
226
227 if (fname == NULL) {
228 return;
229 }
230
231 loc_push_none(&loc);
232 loc_set_file(fname, 0);
233 fp = fopen(fname, "r");
234 if (!fp) {
235 error_report("%s", strerror(errno));
236 exit(1);
237 }
238 while (fgets(line_buf, sizeof(line_buf), fp)) {
239 loc_set_file(fname, ++line_idx);
240 size_t len = strlen(line_buf);
241 if (len > 1) { /* skip empty lines */
242 line_buf[len - 1] = '\0';
243 if ('#' == line_buf[0]) { /* skip commented lines */
244 continue;
245 }
246 trace_enable_events(line_buf);
247 }
248 }
249 if (fclose(fp) != 0) {
250 loc_set_file(fname, 0);
251 error_report("%s", strerror(errno));
252 exit(1);
253 }
254 loc_pop(&loc);
255 }
256
trace_init_file(const char * file)257 void trace_init_file(const char *file)
258 {
259 #ifdef CONFIG_TRACE_SIMPLE
260 st_set_trace_file(file);
261 #elif defined CONFIG_TRACE_LOG
262 /* If both the simple and the log backends are enabled, "--trace file"
263 * only applies to the simple backend; use "-D" for the log backend.
264 */
265 if (file) {
266 qemu_set_log_filename(file, &error_fatal);
267 }
268 #else
269 if (file) {
270 fprintf(stderr, "error: --trace file=...: "
271 "option not supported by the selected tracing backends\n");
272 exit(1);
273 }
274 #endif
275 }
276
trace_fini_vcpu(CPUState * vcpu)277 void trace_fini_vcpu(CPUState *vcpu)
278 {
279 TraceEventIter iter;
280 TraceEvent *ev;
281
282 trace_guest_cpu_exit(vcpu);
283
284 trace_event_iter_init(&iter, NULL);
285 while ((ev = trace_event_iter_next(&iter)) != NULL) {
286 if (trace_event_is_vcpu(ev) &&
287 trace_event_get_state_static(ev) &&
288 trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
289 /* must disable to affect the global counter */
290 trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
291 }
292 }
293 }
294
trace_init_backends(void)295 bool trace_init_backends(void)
296 {
297 #ifdef CONFIG_TRACE_SIMPLE
298 if (!st_init()) {
299 fprintf(stderr, "failed to initialize simple tracing backend.\n");
300 return false;
301 }
302 #endif
303
304 #ifdef CONFIG_TRACE_FTRACE
305 if (!ftrace_init()) {
306 fprintf(stderr, "failed to initialize ftrace backend.\n");
307 return false;
308 }
309 #endif
310
311 #ifdef CONFIG_TRACE_SYSLOG
312 openlog(NULL, LOG_PID, LOG_DAEMON);
313 #endif
314
315 return true;
316 }
317
trace_opt_parse(const char * optarg)318 char *trace_opt_parse(const char *optarg)
319 {
320 char *trace_file;
321 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
322 optarg, true);
323 if (!opts) {
324 exit(1);
325 }
326 if (qemu_opt_get(opts, "enable")) {
327 trace_enable_events(qemu_opt_get(opts, "enable"));
328 }
329 trace_init_events(qemu_opt_get(opts, "events"));
330 trace_file = g_strdup(qemu_opt_get(opts, "file"));
331 qemu_opts_del(opts);
332
333 return trace_file;
334 }
335
trace_get_vcpu_event_count(void)336 uint32_t trace_get_vcpu_event_count(void)
337 {
338 return next_vcpu_id;
339 }
340