xref: /qemu/trace/control.c (revision b7d48952) 
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 
39 QemuOptsList qemu_trace_opts = {
40     .name = "trace",
41     .implied_opt_name = "enable",
42     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
43     .desc = {
44         {
45             .name = "enable",
46             .type = QEMU_OPT_STRING,
47         },
48         {
49             .name = "events",
50             .type = QEMU_OPT_STRING,
51         },{
52             .name = "file",
53             .type = QEMU_OPT_STRING,
54         },
55         { /* end of list */ }
56     },
57 };
58 
59 
60 void trace_event_register_group(TraceEvent **events)
61 {
62     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
63     event_groups[nevent_groups].events = events;
64     nevent_groups++;
65 }
66 
67 
68 TraceEvent *trace_event_name(const char *name)
69 {
70     assert(name != NULL);
71 
72     TraceEventIter iter;
73     TraceEvent *ev;
74     trace_event_iter_init(&iter, NULL);
75     while ((ev = trace_event_iter_next(&iter)) != NULL) {
76         if (strcmp(trace_event_get_name(ev), name) == 0) {
77             return ev;
78         }
79     }
80     return NULL;
81 }
82 
83 static bool pattern_glob(const char *pat, const char *ev)
84 {
85     while (*pat != '\0' && *ev != '\0') {
86         if (*pat == *ev) {
87             pat++;
88             ev++;
89         }
90         else if (*pat == '*') {
91             if (pattern_glob(pat, ev+1)) {
92                 return true;
93             } else if (pattern_glob(pat+1, ev)) {
94                 return true;
95             } else {
96                 return false;
97             }
98         } else {
99             return false;
100         }
101     }
102 
103     while (*pat == '*') {
104         pat++;
105     }
106 
107     if (*pat == '\0' && *ev == '\0') {
108         return true;
109     } else {
110         return false;
111     }
112 }
113 
114 
115 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
116 {
117     iter->event = 0;
118     iter->group = 0;
119     iter->pattern = pattern;
120 }
121 
122 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
123 {
124     while (iter->group < nevent_groups &&
125            event_groups[iter->group].events[iter->event] != NULL) {
126         TraceEvent *ev = event_groups[iter->group].events[iter->event];
127         iter->event++;
128         if (event_groups[iter->group].events[iter->event] == NULL) {
129             iter->event = 0;
130             iter->group++;
131         }
132         if (!iter->pattern ||
133             pattern_glob(iter->pattern,
134                          trace_event_get_name(ev))) {
135             return ev;
136         }
137     }
138 
139     return NULL;
140 }
141 
142 void trace_list_events(void)
143 {
144     TraceEventIter iter;
145     TraceEvent *ev;
146     trace_event_iter_init(&iter, NULL);
147     while ((ev = trace_event_iter_next(&iter)) != NULL) {
148         fprintf(stderr, "%s\n", trace_event_get_name(ev));
149     }
150 }
151 
152 static void do_trace_enable_events(const char *line_buf)
153 {
154     const bool enable = ('-' != line_buf[0]);
155     const char *line_ptr = enable ? line_buf : line_buf + 1;
156     TraceEventIter iter;
157     TraceEvent *ev;
158     bool is_pattern = trace_event_is_pattern(line_ptr);
159 
160     trace_event_iter_init(&iter, line_ptr);
161     while ((ev = trace_event_iter_next(&iter)) != NULL) {
162         if (!trace_event_get_state_static(ev)) {
163             if (!is_pattern) {
164                 error_report("WARNING: trace event '%s' is not traceable",
165                              line_ptr);
166                 return;
167             }
168             continue;
169         }
170 
171         /* start tracing */
172         trace_event_set_state_dynamic(ev, enable);
173         if (!is_pattern) {
174             return;
175         }
176     }
177 
178     if (!is_pattern) {
179         error_report("WARNING: trace event '%s' does not exist",
180                      line_ptr);
181     }
182 }
183 
184 void trace_enable_events(const char *line_buf)
185 {
186     if (is_help_option(line_buf)) {
187         trace_list_events();
188         if (cur_mon == NULL) {
189             exit(0);
190         }
191     } else {
192         do_trace_enable_events(line_buf);
193     }
194 }
195 
196 static void trace_init_events(const char *fname)
197 {
198     Location loc;
199     FILE *fp;
200     char line_buf[1024];
201     size_t line_idx = 0;
202 
203     if (fname == NULL) {
204         return;
205     }
206 
207     loc_push_none(&loc);
208     loc_set_file(fname, 0);
209     fp = fopen(fname, "r");
210     if (!fp) {
211         error_report("%s", strerror(errno));
212         exit(1);
213     }
214     while (fgets(line_buf, sizeof(line_buf), fp)) {
215         loc_set_file(fname, ++line_idx);
216         size_t len = strlen(line_buf);
217         if (len > 1) {              /* skip empty lines */
218             line_buf[len - 1] = '\0';
219             if ('#' == line_buf[0]) { /* skip commented lines */
220                 continue;
221             }
222             trace_enable_events(line_buf);
223         }
224     }
225     if (fclose(fp) != 0) {
226         loc_set_file(fname, 0);
227         error_report("%s", strerror(errno));
228         exit(1);
229     }
230     loc_pop(&loc);
231 }
232 
233 void trace_init_file(const char *file)
234 {
235 #ifdef CONFIG_TRACE_SIMPLE
236     st_set_trace_file(file);
237 #elif defined CONFIG_TRACE_LOG
238     /* If both the simple and the log backends are enabled, "-trace file"
239      * only applies to the simple backend; use "-D" for the log backend.
240      */
241     if (file) {
242         qemu_set_log_filename(file, &error_fatal);
243     }
244 #else
245     if (file) {
246         fprintf(stderr, "error: -trace file=...: "
247                 "option not supported by the selected tracing backends\n");
248         exit(1);
249     }
250 #endif
251 }
252 
253 bool trace_init_backends(void)
254 {
255 #ifdef CONFIG_TRACE_SIMPLE
256     if (!st_init()) {
257         fprintf(stderr, "failed to initialize simple tracing backend.\n");
258         return false;
259     }
260 #endif
261 
262 #ifdef CONFIG_TRACE_FTRACE
263     if (!ftrace_init()) {
264         fprintf(stderr, "failed to initialize ftrace backend.\n");
265         return false;
266     }
267 #endif
268 
269 #ifdef CONFIG_TRACE_SYSLOG
270     openlog(NULL, LOG_PID, LOG_DAEMON);
271 #endif
272 
273     return true;
274 }
275 
276 char *trace_opt_parse(const char *optarg)
277 {
278     char *trace_file;
279     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
280                                              optarg, true);
281     if (!opts) {
282         exit(1);
283     }
284     if (qemu_opt_get(opts, "enable")) {
285         trace_enable_events(qemu_opt_get(opts, "enable"));
286     }
287     trace_init_events(qemu_opt_get(opts, "events"));
288     trace_file = g_strdup(qemu_opt_get(opts, "file"));
289     qemu_opts_del(opts);
290 
291     return trace_file;
292 }
293 
294 uint32_t trace_get_vcpu_event_count(void)
295 {
296     return TRACE_VCPU_EVENT_COUNT;
297 }
298