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