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-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 43 QemuOptsList qemu_trace_opts = { 44 .name = "trace", 45 .implied_opt_name = "enable", 46 .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head), 47 .desc = { 48 { 49 .name = "enable", 50 .type = QEMU_OPT_STRING, 51 }, 52 { 53 .name = "events", 54 .type = QEMU_OPT_STRING, 55 },{ 56 .name = "file", 57 .type = QEMU_OPT_STRING, 58 }, 59 { /* end of list */ } 60 }, 61 }; 62 63 64 void trace_event_register_group(TraceEvent **events) 65 { 66 size_t i; 67 for (i = 0; events[i] != NULL; i++) { 68 events[i]->id = next_id++; 69 if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) { 70 continue; 71 } 72 73 if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) { 74 events[i]->vcpu_id = next_vcpu_id++; 75 } else { 76 warn_report("too many vcpu trace events; dropping '%s'", 77 events[i]->name); 78 } 79 } 80 event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1); 81 event_groups[nevent_groups].events = events; 82 nevent_groups++; 83 } 84 85 86 TraceEvent *trace_event_name(const char *name) 87 { 88 assert(name != NULL); 89 90 TraceEventIter iter; 91 TraceEvent *ev; 92 trace_event_iter_init(&iter, NULL); 93 while ((ev = trace_event_iter_next(&iter)) != NULL) { 94 if (strcmp(trace_event_get_name(ev), name) == 0) { 95 return ev; 96 } 97 } 98 return NULL; 99 } 100 101 static bool pattern_glob(const char *pat, const char *ev) 102 { 103 while (*pat != '\0' && *ev != '\0') { 104 if (*pat == *ev) { 105 pat++; 106 ev++; 107 } 108 else if (*pat == '*') { 109 if (pattern_glob(pat, ev+1)) { 110 return true; 111 } else if (pattern_glob(pat+1, ev)) { 112 return true; 113 } else { 114 return false; 115 } 116 } else { 117 return false; 118 } 119 } 120 121 while (*pat == '*') { 122 pat++; 123 } 124 125 if (*pat == '\0' && *ev == '\0') { 126 return true; 127 } else { 128 return false; 129 } 130 } 131 132 133 void trace_event_iter_init(TraceEventIter *iter, const char *pattern) 134 { 135 iter->event = 0; 136 iter->group = 0; 137 iter->pattern = pattern; 138 } 139 140 TraceEvent *trace_event_iter_next(TraceEventIter *iter) 141 { 142 while (iter->group < nevent_groups && 143 event_groups[iter->group].events[iter->event] != NULL) { 144 TraceEvent *ev = event_groups[iter->group].events[iter->event]; 145 iter->event++; 146 if (event_groups[iter->group].events[iter->event] == NULL) { 147 iter->event = 0; 148 iter->group++; 149 } 150 if (!iter->pattern || 151 pattern_glob(iter->pattern, 152 trace_event_get_name(ev))) { 153 return ev; 154 } 155 } 156 157 return NULL; 158 } 159 160 void trace_list_events(void) 161 { 162 TraceEventIter iter; 163 TraceEvent *ev; 164 trace_event_iter_init(&iter, NULL); 165 while ((ev = trace_event_iter_next(&iter)) != NULL) { 166 fprintf(stderr, "%s\n", trace_event_get_name(ev)); 167 } 168 #ifdef CONFIG_TRACE_DTRACE 169 fprintf(stderr, "This list of names of trace points may be incomplete " 170 "when using the DTrace/SystemTap backends.\n" 171 "Run 'qemu-trace-stap list %s' to print the full list.\n", 172 error_get_progname()); 173 #endif 174 } 175 176 static void do_trace_enable_events(const char *line_buf) 177 { 178 const bool enable = ('-' != line_buf[0]); 179 const char *line_ptr = enable ? line_buf : line_buf + 1; 180 TraceEventIter iter; 181 TraceEvent *ev; 182 bool is_pattern = trace_event_is_pattern(line_ptr); 183 184 trace_event_iter_init(&iter, line_ptr); 185 while ((ev = trace_event_iter_next(&iter)) != NULL) { 186 if (!trace_event_get_state_static(ev)) { 187 if (!is_pattern) { 188 warn_report("trace event '%s' is not traceable", 189 line_ptr); 190 return; 191 } 192 continue; 193 } 194 195 /* start tracing */ 196 trace_event_set_state_dynamic(ev, enable); 197 if (!is_pattern) { 198 return; 199 } 200 } 201 202 if (!is_pattern) { 203 warn_report("trace event '%s' does not exist", 204 line_ptr); 205 } 206 } 207 208 void trace_enable_events(const char *line_buf) 209 { 210 if (is_help_option(line_buf)) { 211 trace_list_events(); 212 if (cur_mon == NULL) { 213 exit(0); 214 } 215 } else { 216 do_trace_enable_events(line_buf); 217 } 218 } 219 220 static void trace_init_events(const char *fname) 221 { 222 Location loc; 223 FILE *fp; 224 char line_buf[1024]; 225 size_t line_idx = 0; 226 227 if (fname == NULL) { 228 return; 229 } 230 231 loc_push_none(&loc); 232 loc_set_file(fname, 0); 233 fp = fopen(fname, "r"); 234 if (!fp) { 235 error_report("%s", strerror(errno)); 236 exit(1); 237 } 238 while (fgets(line_buf, sizeof(line_buf), fp)) { 239 loc_set_file(fname, ++line_idx); 240 size_t len = strlen(line_buf); 241 if (len > 1) { /* skip empty lines */ 242 line_buf[len - 1] = '\0'; 243 if ('#' == line_buf[0]) { /* skip commented lines */ 244 continue; 245 } 246 trace_enable_events(line_buf); 247 } 248 } 249 if (fclose(fp) != 0) { 250 loc_set_file(fname, 0); 251 error_report("%s", strerror(errno)); 252 exit(1); 253 } 254 loc_pop(&loc); 255 } 256 257 void trace_init_file(const char *file) 258 { 259 #ifdef CONFIG_TRACE_SIMPLE 260 st_set_trace_file(file); 261 #elif defined CONFIG_TRACE_LOG 262 /* If both the simple and the log backends are enabled, "--trace file" 263 * only applies to the simple backend; use "-D" for the log backend. 264 */ 265 if (file) { 266 qemu_set_log_filename(file, &error_fatal); 267 } 268 #else 269 if (file) { 270 fprintf(stderr, "error: --trace file=...: " 271 "option not supported by the selected tracing backends\n"); 272 exit(1); 273 } 274 #endif 275 } 276 277 void trace_fini_vcpu(CPUState *vcpu) 278 { 279 TraceEventIter iter; 280 TraceEvent *ev; 281 282 trace_guest_cpu_exit(vcpu); 283 284 trace_event_iter_init(&iter, NULL); 285 while ((ev = trace_event_iter_next(&iter)) != NULL) { 286 if (trace_event_is_vcpu(ev) && 287 trace_event_get_state_static(ev) && 288 trace_event_get_vcpu_state_dynamic(vcpu, ev)) { 289 /* must disable to affect the global counter */ 290 trace_event_set_vcpu_state_dynamic(vcpu, ev, false); 291 } 292 } 293 } 294 295 bool trace_init_backends(void) 296 { 297 #ifdef CONFIG_TRACE_SIMPLE 298 if (!st_init()) { 299 fprintf(stderr, "failed to initialize simple tracing backend.\n"); 300 return false; 301 } 302 #endif 303 304 #ifdef CONFIG_TRACE_FTRACE 305 if (!ftrace_init()) { 306 fprintf(stderr, "failed to initialize ftrace backend.\n"); 307 return false; 308 } 309 #endif 310 311 #ifdef CONFIG_TRACE_SYSLOG 312 openlog(NULL, LOG_PID, LOG_DAEMON); 313 #endif 314 315 return true; 316 } 317 318 char *trace_opt_parse(const char *optarg) 319 { 320 char *trace_file; 321 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"), 322 optarg, true); 323 if (!opts) { 324 exit(1); 325 } 326 if (qemu_opt_get(opts, "enable")) { 327 trace_enable_events(qemu_opt_get(opts, "enable")); 328 } 329 trace_init_events(qemu_opt_get(opts, "events")); 330 trace_file = g_strdup(qemu_opt_get(opts, "file")); 331 qemu_opts_del(opts); 332 333 return trace_file; 334 } 335 336 uint32_t trace_get_vcpu_event_count(void) 337 { 338 return next_vcpu_id; 339 } 340