control.c (8588B)
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 if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) { 72 continue; 73 } 74 75 if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) { 76 events[i]->vcpu_id = next_vcpu_id++; 77 } else { 78 warn_report("too many vcpu trace events; dropping '%s'", 79 events[i]->name); 80 } 81 } 82 event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1); 83 event_groups[nevent_groups].events = events; 84 nevent_groups++; 85 86 #ifdef CONFIG_TRACE_SIMPLE 87 st_init_group(nevent_groups - 1); 88 #endif 89 } 90 91 92 TraceEvent *trace_event_name(const char *name) 93 { 94 assert(name != NULL); 95 96 TraceEventIter iter; 97 TraceEvent *ev; 98 trace_event_iter_init_all(&iter); 99 while ((ev = trace_event_iter_next(&iter)) != NULL) { 100 if (strcmp(trace_event_get_name(ev), name) == 0) { 101 return ev; 102 } 103 } 104 return NULL; 105 } 106 107 void trace_event_iter_init_all(TraceEventIter *iter) 108 { 109 iter->event = 0; 110 iter->group = 0; 111 iter->group_id = -1; 112 iter->pattern = NULL; 113 } 114 115 void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern) 116 { 117 trace_event_iter_init_all(iter); 118 iter->pattern = pattern; 119 } 120 121 void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id) 122 { 123 trace_event_iter_init_all(iter); 124 iter->group_id = group_id; 125 } 126 127 TraceEvent *trace_event_iter_next(TraceEventIter *iter) 128 { 129 while (iter->group < nevent_groups && 130 event_groups[iter->group].events[iter->event] != NULL) { 131 TraceEvent *ev = event_groups[iter->group].events[iter->event]; 132 size_t group = iter->group; 133 iter->event++; 134 if (event_groups[iter->group].events[iter->event] == NULL) { 135 iter->event = 0; 136 iter->group++; 137 } 138 if (iter->pattern && 139 !g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) { 140 continue; 141 } 142 if (iter->group_id != -1 && 143 iter->group_id != group) { 144 continue; 145 } 146 return ev; 147 } 148 149 return NULL; 150 } 151 152 void trace_list_events(FILE *f) 153 { 154 TraceEventIter iter; 155 TraceEvent *ev; 156 trace_event_iter_init_all(&iter); 157 while ((ev = trace_event_iter_next(&iter)) != NULL) { 158 fprintf(f, "%s\n", trace_event_get_name(ev)); 159 } 160 #ifdef CONFIG_TRACE_DTRACE 161 fprintf(f, "This list of names of trace points may be incomplete " 162 "when using the DTrace/SystemTap backends.\n" 163 "Run 'qemu-trace-stap list %s' to print the full list.\n", 164 g_get_prgname()); 165 #endif 166 } 167 168 static void do_trace_enable_events(const char *line_buf) 169 { 170 const bool enable = ('-' != line_buf[0]); 171 const char *line_ptr = enable ? line_buf : line_buf + 1; 172 TraceEventIter iter; 173 TraceEvent *ev; 174 bool is_pattern = trace_event_is_pattern(line_ptr); 175 176 trace_event_iter_init_pattern(&iter, line_ptr); 177 while ((ev = trace_event_iter_next(&iter)) != NULL) { 178 if (!trace_event_get_state_static(ev)) { 179 if (!is_pattern) { 180 warn_report("trace event '%s' is not traceable", 181 line_ptr); 182 return; 183 } 184 continue; 185 } 186 187 /* start tracing */ 188 trace_event_set_state_dynamic(ev, enable); 189 if (!is_pattern) { 190 return; 191 } 192 } 193 194 if (!is_pattern) { 195 warn_report("trace event '%s' does not exist", 196 line_ptr); 197 } 198 } 199 200 void trace_enable_events(const char *line_buf) 201 { 202 if (is_help_option(line_buf)) { 203 trace_list_events(stdout); 204 if (monitor_cur() == NULL) { 205 exit(0); 206 } 207 } else { 208 do_trace_enable_events(line_buf); 209 } 210 } 211 212 static void trace_init_events(const char *fname) 213 { 214 Location loc; 215 FILE *fp; 216 char line_buf[1024]; 217 size_t line_idx = 0; 218 219 if (fname == NULL) { 220 return; 221 } 222 223 loc_push_none(&loc); 224 loc_set_file(fname, 0); 225 fp = fopen(fname, "r"); 226 if (!fp) { 227 error_report("%s", strerror(errno)); 228 exit(1); 229 } 230 while (fgets(line_buf, sizeof(line_buf), fp)) { 231 loc_set_file(fname, ++line_idx); 232 size_t len = strlen(line_buf); 233 if (len > 1) { /* skip empty lines */ 234 line_buf[len - 1] = '\0'; 235 if ('#' == line_buf[0]) { /* skip commented lines */ 236 continue; 237 } 238 trace_enable_events(line_buf); 239 } 240 } 241 if (fclose(fp) != 0) { 242 loc_set_file(fname, 0); 243 error_report("%s", strerror(errno)); 244 exit(1); 245 } 246 loc_pop(&loc); 247 } 248 249 void trace_init_file(void) 250 { 251 #ifdef CONFIG_TRACE_SIMPLE 252 st_set_trace_file(trace_opts_file); 253 if (init_trace_on_startup) { 254 st_set_trace_file_enabled(true); 255 } 256 #elif defined CONFIG_TRACE_LOG 257 /* 258 * If both the simple and the log backends are enabled, "--trace file" 259 * only applies to the simple backend; use "-D" for the log 260 * backend. However we should only override -D if we actually have 261 * something to override it with. 262 */ 263 if (trace_opts_file) { 264 qemu_set_log_filename(trace_opts_file, &error_fatal); 265 } 266 #else 267 if (trace_opts_file) { 268 fprintf(stderr, "error: --trace file=...: " 269 "option not supported by the selected tracing backends\n"); 270 exit(1); 271 } 272 #endif 273 } 274 275 void trace_fini_vcpu(CPUState *vcpu) 276 { 277 TraceEventIter iter; 278 TraceEvent *ev; 279 280 trace_guest_cpu_exit(vcpu); 281 282 trace_event_iter_init_all(&iter); 283 while ((ev = trace_event_iter_next(&iter)) != NULL) { 284 if (trace_event_is_vcpu(ev) && 285 trace_event_get_state_static(ev) && 286 trace_event_get_vcpu_state_dynamic(vcpu, ev)) { 287 /* must disable to affect the global counter */ 288 trace_event_set_vcpu_state_dynamic(vcpu, ev, false); 289 } 290 } 291 } 292 293 bool trace_init_backends(void) 294 { 295 #ifdef CONFIG_TRACE_SIMPLE 296 if (!st_init()) { 297 fprintf(stderr, "failed to initialize simple tracing backend.\n"); 298 return false; 299 } 300 #endif 301 302 #ifdef CONFIG_TRACE_FTRACE 303 if (!ftrace_init()) { 304 fprintf(stderr, "failed to initialize ftrace backend.\n"); 305 return false; 306 } 307 #endif 308 309 #ifdef CONFIG_TRACE_SYSLOG 310 openlog(NULL, LOG_PID, LOG_DAEMON); 311 #endif 312 313 return true; 314 } 315 316 void trace_opt_parse(const char *optarg) 317 { 318 QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"), 319 optarg, true); 320 if (!opts) { 321 exit(1); 322 } 323 if (qemu_opt_get(opts, "enable")) { 324 trace_enable_events(qemu_opt_get(opts, "enable")); 325 } 326 trace_init_events(qemu_opt_get(opts, "events")); 327 init_trace_on_startup = true; 328 g_free(trace_opts_file); 329 trace_opts_file = g_strdup(qemu_opt_get(opts, "file")); 330 qemu_opts_del(opts); 331 } 332 333 uint32_t trace_get_vcpu_event_count(void) 334 { 335 return next_vcpu_id; 336 }