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