quorum: Avoid bdrv_aio_writev() for rewrites
[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 #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 }