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