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