xref: /qemu/trace/control.c (revision 814bb12a) 
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 
30 int trace_events_enabled_count;
31 
32 typedef struct TraceEventGroup {
33     TraceEvent **events;
34 } TraceEventGroup;
35 
36 static TraceEventGroup *event_groups;
37 static size_t nevent_groups;
38 static uint32_t next_id;
39 static uint32_t next_vcpu_id;
40 
41 QemuOptsList qemu_trace_opts = {
42     .name = "trace",
43     .implied_opt_name = "enable",
44     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
45     .desc = {
46         {
47             .name = "enable",
48             .type = QEMU_OPT_STRING,
49         },
50         {
51             .name = "events",
52             .type = QEMU_OPT_STRING,
53         },{
54             .name = "file",
55             .type = QEMU_OPT_STRING,
56         },
57         { /* end of list */ }
58     },
59 };
60 
61 
62 void trace_event_register_group(TraceEvent **events)
63 {
64     size_t i;
65     for (i = 0; events[i] != NULL; i++) {
66         events[i]->id = next_id++;
67         if (events[i]->vcpu_id != TRACE_VCPU_EVENT_NONE) {
68             events[i]->vcpu_id = next_vcpu_id++;
69         }
70     }
71     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
72     event_groups[nevent_groups].events = events;
73     nevent_groups++;
74 }
75 
76 
77 TraceEvent *trace_event_name(const char *name)
78 {
79     assert(name != NULL);
80 
81     TraceEventIter iter;
82     TraceEvent *ev;
83     trace_event_iter_init(&iter, NULL);
84     while ((ev = trace_event_iter_next(&iter)) != NULL) {
85         if (strcmp(trace_event_get_name(ev), name) == 0) {
86             return ev;
87         }
88     }
89     return NULL;
90 }
91 
92 static bool pattern_glob(const char *pat, const char *ev)
93 {
94     while (*pat != '\0' && *ev != '\0') {
95         if (*pat == *ev) {
96             pat++;
97             ev++;
98         }
99         else if (*pat == '*') {
100             if (pattern_glob(pat, ev+1)) {
101                 return true;
102             } else if (pattern_glob(pat+1, ev)) {
103                 return true;
104             } else {
105                 return false;
106             }
107         } else {
108             return false;
109         }
110     }
111 
112     while (*pat == '*') {
113         pat++;
114     }
115 
116     if (*pat == '\0' && *ev == '\0') {
117         return true;
118     } else {
119         return false;
120     }
121 }
122 
123 
124 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
125 {
126     iter->event = 0;
127     iter->group = 0;
128     iter->pattern = pattern;
129 }
130 
131 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
132 {
133     while (iter->group < nevent_groups &&
134            event_groups[iter->group].events[iter->event] != NULL) {
135         TraceEvent *ev = event_groups[iter->group].events[iter->event];
136         iter->event++;
137         if (event_groups[iter->group].events[iter->event] == NULL) {
138             iter->event = 0;
139             iter->group++;
140         }
141         if (!iter->pattern ||
142             pattern_glob(iter->pattern,
143                          trace_event_get_name(ev))) {
144             return ev;
145         }
146     }
147 
148     return NULL;
149 }
150 
151 void trace_list_events(void)
152 {
153     TraceEventIter iter;
154     TraceEvent *ev;
155     trace_event_iter_init(&iter, NULL);
156     while ((ev = trace_event_iter_next(&iter)) != NULL) {
157         fprintf(stderr, "%s\n", trace_event_get_name(ev));
158     }
159 }
160 
161 static void do_trace_enable_events(const char *line_buf)
162 {
163     const bool enable = ('-' != line_buf[0]);
164     const char *line_ptr = enable ? line_buf : line_buf + 1;
165     TraceEventIter iter;
166     TraceEvent *ev;
167     bool is_pattern = trace_event_is_pattern(line_ptr);
168 
169     trace_event_iter_init(&iter, line_ptr);
170     while ((ev = trace_event_iter_next(&iter)) != NULL) {
171         if (!trace_event_get_state_static(ev)) {
172             if (!is_pattern) {
173                 error_report("WARNING: trace event '%s' is not traceable",
174                              line_ptr);
175                 return;
176             }
177             continue;
178         }
179 
180         /* start tracing */
181         trace_event_set_state_dynamic(ev, enable);
182         if (!is_pattern) {
183             return;
184         }
185     }
186 
187     if (!is_pattern) {
188         error_report("WARNING: trace event '%s' does not exist",
189                      line_ptr);
190     }
191 }
192 
193 void trace_enable_events(const char *line_buf)
194 {
195     if (is_help_option(line_buf)) {
196         trace_list_events();
197         if (cur_mon == NULL) {
198             exit(0);
199         }
200     } else {
201         do_trace_enable_events(line_buf);
202     }
203 }
204 
205 static void trace_init_events(const char *fname)
206 {
207     Location loc;
208     FILE *fp;
209     char line_buf[1024];
210     size_t line_idx = 0;
211 
212     if (fname == NULL) {
213         return;
214     }
215 
216     loc_push_none(&loc);
217     loc_set_file(fname, 0);
218     fp = fopen(fname, "r");
219     if (!fp) {
220         error_report("%s", strerror(errno));
221         exit(1);
222     }
223     while (fgets(line_buf, sizeof(line_buf), fp)) {
224         loc_set_file(fname, ++line_idx);
225         size_t len = strlen(line_buf);
226         if (len > 1) {              /* skip empty lines */
227             line_buf[len - 1] = '\0';
228             if ('#' == line_buf[0]) { /* skip commented lines */
229                 continue;
230             }
231             trace_enable_events(line_buf);
232         }
233     }
234     if (fclose(fp) != 0) {
235         loc_set_file(fname, 0);
236         error_report("%s", strerror(errno));
237         exit(1);
238     }
239     loc_pop(&loc);
240 }
241 
242 void trace_init_file(const char *file)
243 {
244 #ifdef CONFIG_TRACE_SIMPLE
245     st_set_trace_file(file);
246 #elif defined CONFIG_TRACE_LOG
247     /* If both the simple and the log backends are enabled, "-trace file"
248      * only applies to the simple backend; use "-D" for the log backend.
249      */
250     if (file) {
251         qemu_set_log_filename(file, &error_fatal);
252     }
253 #else
254     if (file) {
255         fprintf(stderr, "error: -trace file=...: "
256                 "option not supported by the selected tracing backends\n");
257         exit(1);
258     }
259 #endif
260 }
261 
262 bool trace_init_backends(void)
263 {
264 #ifdef CONFIG_TRACE_SIMPLE
265     if (!st_init()) {
266         fprintf(stderr, "failed to initialize simple tracing backend.\n");
267         return false;
268     }
269 #endif
270 
271 #ifdef CONFIG_TRACE_FTRACE
272     if (!ftrace_init()) {
273         fprintf(stderr, "failed to initialize ftrace backend.\n");
274         return false;
275     }
276 #endif
277 
278 #ifdef CONFIG_TRACE_SYSLOG
279     openlog(NULL, LOG_PID, LOG_DAEMON);
280 #endif
281 
282     return true;
283 }
284 
285 char *trace_opt_parse(const char *optarg)
286 {
287     char *trace_file;
288     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
289                                              optarg, true);
290     if (!opts) {
291         exit(1);
292     }
293     if (qemu_opt_get(opts, "enable")) {
294         trace_enable_events(qemu_opt_get(opts, "enable"));
295     }
296     trace_init_events(qemu_opt_get(opts, "events"));
297     trace_file = g_strdup(qemu_opt_get(opts, "file"));
298     qemu_opts_del(opts);
299 
300     return trace_file;
301 }
302 
303 uint32_t trace_get_vcpu_event_count(void)
304 {
305     return next_vcpu_id;
306 }
307