xref: /qemu/trace/control.c (revision 6402cbbb) 
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 #ifdef CONFIG_TRACE_SIMPLE
14 #include "trace/simple.h"
15 #endif
16 #ifdef CONFIG_TRACE_FTRACE
17 #include "trace/ftrace.h"
18 #endif
19 #ifdef CONFIG_TRACE_LOG
20 #include "qemu/log.h"
21 #endif
22 #ifdef CONFIG_TRACE_SYSLOG
23 #include <syslog.h>
24 #endif
25 #include "qapi/error.h"
26 #include "qemu/error-report.h"
27 #include "qemu/config-file.h"
28 #include "monitor/monitor.h"
29 #include "trace-root.h"
30 
31 int trace_events_enabled_count;
32 
33 typedef struct TraceEventGroup {
34     TraceEvent **events;
35 } TraceEventGroup;
36 
37 static TraceEventGroup *event_groups;
38 static size_t nevent_groups;
39 static uint32_t next_id;
40 static uint32_t next_vcpu_id;
41 
42 QemuOptsList qemu_trace_opts = {
43     .name = "trace",
44     .implied_opt_name = "enable",
45     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
46     .desc = {
47         {
48             .name = "enable",
49             .type = QEMU_OPT_STRING,
50         },
51         {
52             .name = "events",
53             .type = QEMU_OPT_STRING,
54         },{
55             .name = "file",
56             .type = QEMU_OPT_STRING,
57         },
58         { /* end of list */ }
59     },
60 };
61 
62 
63 void trace_event_register_group(TraceEvent **events)
64 {
65     size_t i;
66     for (i = 0; events[i] != NULL; i++) {
67         events[i]->id = next_id++;
68         if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
69             continue;
70         }
71 
72         if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
73             events[i]->vcpu_id = next_vcpu_id++;
74         } else {
75             error_report("WARNING: too many vcpu trace events; dropping '%s'",
76                          events[i]->name);
77         }
78     }
79     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
80     event_groups[nevent_groups].events = events;
81     nevent_groups++;
82 }
83 
84 
85 TraceEvent *trace_event_name(const char *name)
86 {
87     assert(name != NULL);
88 
89     TraceEventIter iter;
90     TraceEvent *ev;
91     trace_event_iter_init(&iter, NULL);
92     while ((ev = trace_event_iter_next(&iter)) != NULL) {
93         if (strcmp(trace_event_get_name(ev), name) == 0) {
94             return ev;
95         }
96     }
97     return NULL;
98 }
99 
100 static bool pattern_glob(const char *pat, const char *ev)
101 {
102     while (*pat != '\0' && *ev != '\0') {
103         if (*pat == *ev) {
104             pat++;
105             ev++;
106         }
107         else if (*pat == '*') {
108             if (pattern_glob(pat, ev+1)) {
109                 return true;
110             } else if (pattern_glob(pat+1, ev)) {
111                 return true;
112             } else {
113                 return false;
114             }
115         } else {
116             return false;
117         }
118     }
119 
120     while (*pat == '*') {
121         pat++;
122     }
123 
124     if (*pat == '\0' && *ev == '\0') {
125         return true;
126     } else {
127         return false;
128     }
129 }
130 
131 
132 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
133 {
134     iter->event = 0;
135     iter->group = 0;
136     iter->pattern = pattern;
137 }
138 
139 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
140 {
141     while (iter->group < nevent_groups &&
142            event_groups[iter->group].events[iter->event] != NULL) {
143         TraceEvent *ev = event_groups[iter->group].events[iter->event];
144         iter->event++;
145         if (event_groups[iter->group].events[iter->event] == NULL) {
146             iter->event = 0;
147             iter->group++;
148         }
149         if (!iter->pattern ||
150             pattern_glob(iter->pattern,
151                          trace_event_get_name(ev))) {
152             return ev;
153         }
154     }
155 
156     return NULL;
157 }
158 
159 void trace_list_events(void)
160 {
161     TraceEventIter iter;
162     TraceEvent *ev;
163     trace_event_iter_init(&iter, NULL);
164     while ((ev = trace_event_iter_next(&iter)) != NULL) {
165         fprintf(stderr, "%s\n", trace_event_get_name(ev));
166     }
167 }
168 
169 static void do_trace_enable_events(const char *line_buf)
170 {
171     const bool enable = ('-' != line_buf[0]);
172     const char *line_ptr = enable ? line_buf : line_buf + 1;
173     TraceEventIter iter;
174     TraceEvent *ev;
175     bool is_pattern = trace_event_is_pattern(line_ptr);
176 
177     trace_event_iter_init(&iter, line_ptr);
178     while ((ev = trace_event_iter_next(&iter)) != NULL) {
179         if (!trace_event_get_state_static(ev)) {
180             if (!is_pattern) {
181                 warn_report("trace event '%s' is not traceable",
182                             line_ptr);
183                 return;
184             }
185             continue;
186         }
187 
188         /* start tracing */
189         trace_event_set_state_dynamic(ev, enable);
190         if (!is_pattern) {
191             return;
192         }
193     }
194 
195     if (!is_pattern) {
196         warn_report("trace event '%s' does not exist",
197                     line_ptr);
198     }
199 }
200 
201 void trace_enable_events(const char *line_buf)
202 {
203     if (is_help_option(line_buf)) {
204         trace_list_events();
205         if (cur_mon == NULL) {
206             exit(0);
207         }
208     } else {
209         do_trace_enable_events(line_buf);
210     }
211 }
212 
213 static void trace_init_events(const char *fname)
214 {
215     Location loc;
216     FILE *fp;
217     char line_buf[1024];
218     size_t line_idx = 0;
219 
220     if (fname == NULL) {
221         return;
222     }
223 
224     loc_push_none(&loc);
225     loc_set_file(fname, 0);
226     fp = fopen(fname, "r");
227     if (!fp) {
228         error_report("%s", strerror(errno));
229         exit(1);
230     }
231     while (fgets(line_buf, sizeof(line_buf), fp)) {
232         loc_set_file(fname, ++line_idx);
233         size_t len = strlen(line_buf);
234         if (len > 1) {              /* skip empty lines */
235             line_buf[len - 1] = '\0';
236             if ('#' == line_buf[0]) { /* skip commented lines */
237                 continue;
238             }
239             trace_enable_events(line_buf);
240         }
241     }
242     if (fclose(fp) != 0) {
243         loc_set_file(fname, 0);
244         error_report("%s", strerror(errno));
245         exit(1);
246     }
247     loc_pop(&loc);
248 }
249 
250 void trace_init_file(const char *file)
251 {
252 #ifdef CONFIG_TRACE_SIMPLE
253     st_set_trace_file(file);
254 #elif defined CONFIG_TRACE_LOG
255     /* If both the simple and the log backends are enabled, "-trace file"
256      * only applies to the simple backend; use "-D" for the log backend.
257      */
258     if (file) {
259         qemu_set_log_filename(file, &error_fatal);
260     }
261 #else
262     if (file) {
263         fprintf(stderr, "error: -trace file=...: "
264                 "option not supported by the selected tracing backends\n");
265         exit(1);
266     }
267 #endif
268 }
269 
270 void trace_fini_vcpu(CPUState *vcpu)
271 {
272     TraceEventIter iter;
273     TraceEvent *ev;
274 
275     trace_guest_cpu_exit(vcpu);
276 
277     trace_event_iter_init(&iter, NULL);
278     while ((ev = trace_event_iter_next(&iter)) != NULL) {
279         if (trace_event_is_vcpu(ev) &&
280             trace_event_get_state_static(ev) &&
281             trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
282             /* must disable to affect the global counter */
283             trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
284         }
285     }
286 }
287 
288 bool trace_init_backends(void)
289 {
290 #ifdef CONFIG_TRACE_SIMPLE
291     if (!st_init()) {
292         fprintf(stderr, "failed to initialize simple tracing backend.\n");
293         return false;
294     }
295 #endif
296 
297 #ifdef CONFIG_TRACE_FTRACE
298     if (!ftrace_init()) {
299         fprintf(stderr, "failed to initialize ftrace backend.\n");
300         return false;
301     }
302 #endif
303 
304 #ifdef CONFIG_TRACE_SYSLOG
305     openlog(NULL, LOG_PID, LOG_DAEMON);
306 #endif
307 
308     return true;
309 }
310 
311 char *trace_opt_parse(const char *optarg)
312 {
313     char *trace_file;
314     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
315                                              optarg, true);
316     if (!opts) {
317         exit(1);
318     }
319     if (qemu_opt_get(opts, "enable")) {
320         trace_enable_events(qemu_opt_get(opts, "enable"));
321     }
322     trace_init_events(qemu_opt_get(opts, "events"));
323     trace_file = g_strdup(qemu_opt_get(opts, "file"));
324     qemu_opts_del(opts);
325 
326     return trace_file;
327 }
328 
329 uint32_t trace_get_vcpu_event_count(void)
330 {
331     return next_vcpu_id;
332 }
333