xref: /qemu/trace/control.c (revision 2c533c54) 
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 #include "qapi/error.h"
23 #include "qemu/error-report.h"
24 #include "qemu/config-file.h"
25 #include "monitor/monitor.h"
26 
27 int trace_events_enabled_count;
28 /*
29  * Interpretation depends on wether the event has the 'vcpu' property:
30  * - false: Boolean value indicating whether the event is active.
31  * - true : Integral counting the number of vCPUs that have this event enabled.
32  */
33 uint16_t trace_events_dstate[TRACE_EVENT_COUNT];
34 /* Marks events for late vCPU state init */
35 static bool trace_events_dstate_init[TRACE_EVENT_COUNT];
36 
37 QemuOptsList qemu_trace_opts = {
38     .name = "trace",
39     .implied_opt_name = "enable",
40     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
41     .desc = {
42         {
43             .name = "enable",
44             .type = QEMU_OPT_STRING,
45         },
46         {
47             .name = "events",
48             .type = QEMU_OPT_STRING,
49         },{
50             .name = "file",
51             .type = QEMU_OPT_STRING,
52         },
53         { /* end of list */ }
54     },
55 };
56 
57 
58 TraceEvent *trace_event_name(const char *name)
59 {
60     assert(name != NULL);
61 
62     TraceEventID i;
63     for (i = 0; i < trace_event_count(); i++) {
64         TraceEvent *ev = trace_event_id(i);
65         if (strcmp(trace_event_get_name(ev), name) == 0) {
66             return ev;
67         }
68     }
69     return NULL;
70 }
71 
72 static bool pattern_glob(const char *pat, const char *ev)
73 {
74     while (*pat != '\0' && *ev != '\0') {
75         if (*pat == *ev) {
76             pat++;
77             ev++;
78         }
79         else if (*pat == '*') {
80             if (pattern_glob(pat, ev+1)) {
81                 return true;
82             } else if (pattern_glob(pat+1, ev)) {
83                 return true;
84             } else {
85                 return false;
86             }
87         } else {
88             return false;
89         }
90     }
91 
92     while (*pat == '*') {
93         pat++;
94     }
95 
96     if (*pat == '\0' && *ev == '\0') {
97         return true;
98     } else {
99         return false;
100     }
101 }
102 
103 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
104 {
105     assert(pat != NULL);
106 
107     TraceEventID i;
108 
109     if (ev == NULL) {
110         i = -1;
111     } else {
112         i = trace_event_get_id(ev);
113     }
114     i++;
115 
116     while (i < trace_event_count()) {
117         TraceEvent *res = trace_event_id(i);
118         if (pattern_glob(pat, trace_event_get_name(res))) {
119             return res;
120         }
121         i++;
122     }
123 
124     return NULL;
125 }
126 
127 void trace_list_events(void)
128 {
129     int i;
130     for (i = 0; i < trace_event_count(); i++) {
131         TraceEvent *res = trace_event_id(i);
132         fprintf(stderr, "%s\n", trace_event_get_name(res));
133     }
134 }
135 
136 static void do_trace_enable_events(const char *line_buf)
137 {
138     const bool enable = ('-' != line_buf[0]);
139     const char *line_ptr = enable ? line_buf : line_buf + 1;
140 
141     if (trace_event_is_pattern(line_ptr)) {
142         TraceEvent *ev = NULL;
143         while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
144             if (trace_event_get_state_static(ev)) {
145                 /* start tracing */
146                 trace_event_set_state_dynamic(ev, enable);
147                 /* mark for late vCPU init */
148                 trace_events_dstate_init[ev->id] = true;
149             }
150         }
151     } else {
152         TraceEvent *ev = trace_event_name(line_ptr);
153         if (ev == NULL) {
154             error_report("WARNING: trace event '%s' does not exist",
155                          line_ptr);
156         } else if (!trace_event_get_state_static(ev)) {
157             error_report("WARNING: trace event '%s' is not traceable",
158                          line_ptr);
159         } else {
160             /* start tracing */
161             trace_event_set_state_dynamic(ev, enable);
162             /* mark for late vCPU init */
163             trace_events_dstate_init[ev->id] = true;
164         }
165     }
166 }
167 
168 void trace_enable_events(const char *line_buf)
169 {
170     if (is_help_option(line_buf)) {
171         trace_list_events();
172         if (cur_mon == NULL) {
173             exit(0);
174         }
175     } else {
176         do_trace_enable_events(line_buf);
177     }
178 }
179 
180 static void trace_init_events(const char *fname)
181 {
182     Location loc;
183     FILE *fp;
184     char line_buf[1024];
185     size_t line_idx = 0;
186 
187     if (fname == NULL) {
188         return;
189     }
190 
191     loc_push_none(&loc);
192     loc_set_file(fname, 0);
193     fp = fopen(fname, "r");
194     if (!fp) {
195         error_report("%s", strerror(errno));
196         exit(1);
197     }
198     while (fgets(line_buf, sizeof(line_buf), fp)) {
199         loc_set_file(fname, ++line_idx);
200         size_t len = strlen(line_buf);
201         if (len > 1) {              /* skip empty lines */
202             line_buf[len - 1] = '\0';
203             if ('#' == line_buf[0]) { /* skip commented lines */
204                 continue;
205             }
206             trace_enable_events(line_buf);
207         }
208     }
209     if (fclose(fp) != 0) {
210         loc_set_file(fname, 0);
211         error_report("%s", strerror(errno));
212         exit(1);
213     }
214     loc_pop(&loc);
215 }
216 
217 void trace_init_file(const char *file)
218 {
219 #ifdef CONFIG_TRACE_SIMPLE
220     st_set_trace_file(file);
221 #elif defined CONFIG_TRACE_LOG
222     /* If both the simple and the log backends are enabled, "-trace file"
223      * only applies to the simple backend; use "-D" for the log backend.
224      */
225     if (file) {
226         qemu_set_log_filename(file, &error_fatal);
227     }
228 #else
229     if (file) {
230         fprintf(stderr, "error: -trace file=...: "
231                 "option not supported by the selected tracing backends\n");
232         exit(1);
233     }
234 #endif
235 }
236 
237 bool trace_init_backends(void)
238 {
239 #ifdef CONFIG_TRACE_SIMPLE
240     if (!st_init()) {
241         fprintf(stderr, "failed to initialize simple tracing backend.\n");
242         return false;
243     }
244 #endif
245 
246 #ifdef CONFIG_TRACE_FTRACE
247     if (!ftrace_init()) {
248         fprintf(stderr, "failed to initialize ftrace backend.\n");
249         return false;
250     }
251 #endif
252 
253     return true;
254 }
255 
256 char *trace_opt_parse(const char *optarg)
257 {
258     char *trace_file;
259     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
260                                              optarg, true);
261     if (!opts) {
262         exit(1);
263     }
264     if (qemu_opt_get(opts, "enable")) {
265         trace_enable_events(qemu_opt_get(opts, "enable"));
266     }
267     trace_init_events(qemu_opt_get(opts, "events"));
268     trace_file = g_strdup(qemu_opt_get(opts, "file"));
269     qemu_opts_del(opts);
270 
271     return trace_file;
272 }
273 
274 void trace_init_vcpu_events(void)
275 {
276     TraceEvent *ev = NULL;
277     while ((ev = trace_event_pattern("*", ev)) != NULL) {
278         if (trace_event_is_vcpu(ev) &&
279             trace_event_get_state_static(ev) &&
280             trace_events_dstate_init[ev->id]) {
281             trace_event_set_state_dynamic(ev, true);
282         }
283     }
284 }
285