xref: /openbmc/qemu/trace/control.c (revision 05caa062)
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/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 static bool init_trace_on_startup;
43 static char *trace_opts_file;
44 
45 QemuOptsList qemu_trace_opts = {
46     .name = "trace",
47     .implied_opt_name = "enable",
48     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
49     .desc = {
50         {
51             .name = "enable",
52             .type = QEMU_OPT_STRING,
53         },
54         {
55             .name = "events",
56             .type = QEMU_OPT_STRING,
57         },{
58             .name = "file",
59             .type = QEMU_OPT_STRING,
60         },
61         { /* end of list */ }
62     },
63 };
64 
65 
66 void trace_event_register_group(TraceEvent **events)
67 {
68     size_t i;
69     for (i = 0; events[i] != NULL; i++) {
70         events[i]->id = next_id++;
71     }
72     event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
73     event_groups[nevent_groups].events = events;
74     nevent_groups++;
75 
76 #ifdef CONFIG_TRACE_SIMPLE
77     st_init_group(nevent_groups - 1);
78 #endif
79 }
80 
81 
82 TraceEvent *trace_event_name(const char *name)
83 {
84     assert(name != NULL);
85 
86     TraceEventIter iter;
87     TraceEvent *ev;
88     trace_event_iter_init_all(&iter);
89     while ((ev = trace_event_iter_next(&iter)) != NULL) {
90         if (strcmp(trace_event_get_name(ev), name) == 0) {
91             return ev;
92         }
93     }
94     return NULL;
95 }
96 
97 void trace_event_iter_init_all(TraceEventIter *iter)
98 {
99     iter->event = 0;
100     iter->group = 0;
101     iter->group_id = -1;
102     iter->pattern = NULL;
103 }
104 
105 void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern)
106 {
107     trace_event_iter_init_all(iter);
108     iter->pattern = pattern;
109 }
110 
111 void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id)
112 {
113     trace_event_iter_init_all(iter);
114     iter->group_id = group_id;
115 }
116 
117 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
118 {
119     while (iter->group < nevent_groups &&
120            event_groups[iter->group].events[iter->event] != NULL) {
121         TraceEvent *ev = event_groups[iter->group].events[iter->event];
122         size_t group = iter->group;
123         iter->event++;
124         if (event_groups[iter->group].events[iter->event] == NULL) {
125             iter->event = 0;
126             iter->group++;
127         }
128         if (iter->pattern &&
129             !g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
130             continue;
131         }
132         if (iter->group_id != -1 &&
133             iter->group_id != group) {
134             continue;
135         }
136         return ev;
137     }
138 
139     return NULL;
140 }
141 
142 void trace_list_events(FILE *f)
143 {
144     TraceEventIter iter;
145     TraceEvent *ev;
146     trace_event_iter_init_all(&iter);
147     while ((ev = trace_event_iter_next(&iter)) != NULL) {
148         fprintf(f, "%s\n", trace_event_get_name(ev));
149     }
150 #ifdef CONFIG_TRACE_DTRACE
151     fprintf(f, "This list of names of trace points may be incomplete "
152                "when using the DTrace/SystemTap backends.\n"
153                "Run 'qemu-trace-stap list %s' to print the full list.\n",
154             g_get_prgname());
155 #endif
156 }
157 
158 static void do_trace_enable_events(const char *line_buf)
159 {
160     const bool enable = ('-' != line_buf[0]);
161     const char *line_ptr = enable ? line_buf : line_buf + 1;
162     TraceEventIter iter;
163     TraceEvent *ev;
164     bool is_pattern = trace_event_is_pattern(line_ptr);
165 
166     trace_event_iter_init_pattern(&iter, line_ptr);
167     while ((ev = trace_event_iter_next(&iter)) != NULL) {
168         if (!trace_event_get_state_static(ev)) {
169             if (!is_pattern) {
170                 warn_report("trace event '%s' is not traceable",
171                             line_ptr);
172                 return;
173             }
174             continue;
175         }
176 
177         /* start tracing */
178         trace_event_set_state_dynamic(ev, enable);
179         if (!is_pattern) {
180             return;
181         }
182     }
183 
184     if (!is_pattern) {
185         warn_report("trace event '%s' does not exist",
186                     line_ptr);
187     }
188 }
189 
190 void trace_enable_events(const char *line_buf)
191 {
192     if (is_help_option(line_buf)) {
193         trace_list_events(stdout);
194         if (monitor_cur() == NULL) {
195             exit(0);
196         }
197     } else {
198         do_trace_enable_events(line_buf);
199     }
200 }
201 
202 static void trace_init_events(const char *fname)
203 {
204     Location loc;
205     FILE *fp;
206     char line_buf[1024];
207     size_t line_idx = 0;
208 
209     if (fname == NULL) {
210         return;
211     }
212 
213     loc_push_none(&loc);
214     loc_set_file(fname, 0);
215     fp = fopen(fname, "r");
216     if (!fp) {
217         error_report("%s", strerror(errno));
218         exit(1);
219     }
220     while (fgets(line_buf, sizeof(line_buf), fp)) {
221         loc_set_file(fname, ++line_idx);
222         size_t len = strlen(line_buf);
223         if (len > 1) {              /* skip empty lines */
224             line_buf[len - 1] = '\0';
225             if ('#' == line_buf[0]) { /* skip commented lines */
226                 continue;
227             }
228             trace_enable_events(line_buf);
229         }
230     }
231     if (fclose(fp) != 0) {
232         loc_set_file(fname, 0);
233         error_report("%s", strerror(errno));
234         exit(1);
235     }
236     loc_pop(&loc);
237 }
238 
239 void trace_init_file(void)
240 {
241 #ifdef CONFIG_TRACE_SIMPLE
242     st_set_trace_file(trace_opts_file);
243     if (init_trace_on_startup) {
244         st_set_trace_file_enabled(true);
245     }
246 #elif defined CONFIG_TRACE_LOG
247     /*
248      * If both the simple and the log backends are enabled, "--trace file"
249      * only applies to the simple backend; use "-D" for the log
250      * backend. However we should only override -D if we actually have
251      * something to override it with.
252      */
253     if (trace_opts_file) {
254         qemu_set_log_filename(trace_opts_file, &error_fatal);
255     }
256 #else
257     if (trace_opts_file) {
258         fprintf(stderr, "error: --trace file=...: "
259                 "option not supported by the selected tracing backends\n");
260         exit(1);
261     }
262 #endif
263 }
264 
265 bool trace_init_backends(void)
266 {
267 #ifdef CONFIG_TRACE_SIMPLE
268     if (!st_init()) {
269         fprintf(stderr, "failed to initialize simple tracing backend.\n");
270         return false;
271     }
272 #endif
273 
274 #ifdef CONFIG_TRACE_FTRACE
275     if (!ftrace_init()) {
276         fprintf(stderr, "failed to initialize ftrace backend.\n");
277         return false;
278     }
279 #endif
280 
281 #ifdef CONFIG_TRACE_SYSLOG
282     openlog(NULL, LOG_PID, LOG_DAEMON);
283 #endif
284 
285     return true;
286 }
287 
288 void trace_opt_parse(const char *optstr)
289 {
290     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
291                                              optstr, true);
292     if (!opts) {
293         exit(1);
294     }
295     if (qemu_opt_get(opts, "enable")) {
296         trace_enable_events(qemu_opt_get(opts, "enable"));
297     }
298     trace_init_events(qemu_opt_get(opts, "events"));
299     init_trace_on_startup = true;
300     g_free(trace_opts_file);
301     trace_opts_file = g_strdup(qemu_opt_get(opts, "file"));
302     qemu_opts_del(opts);
303 }
304 
305 uint32_t trace_get_vcpu_event_count(void)
306 {
307     return next_vcpu_id;
308 }
309