trace/control.c

   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-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 (cur_mon == 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 #elif defined CONFIG_TRACE_LOG
 229     /*
 230      * If both the simple and the log backends are enabled, "--trace file"
 231      * only applies to the simple backend; use "-D" for the log
 232      * backend. However we should only override -D if we actually have
 233      * something to override it with.
 234      */
 235     if (file) {
 236         qemu_set_log_filename(file, &error_fatal);
 237     }
 238 #else
 239     if (file) {
 240         fprintf(stderr, "error: --trace file=...: "
 241                 "option not supported by the selected tracing backends\n");
 242         exit(1);
 243     }
 244 #endif
 245 }
 246
 247 void trace_fini_vcpu(CPUState *vcpu)
 248 {
 249     TraceEventIter iter;
 250     TraceEvent *ev;
 251
 252     trace_guest_cpu_exit(vcpu);
 253
 254     trace_event_iter_init(&iter, NULL);
 255     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 256         if (trace_event_is_vcpu(ev) &&
 257             trace_event_get_state_static(ev) &&
 258             trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
 259             /* must disable to affect the global counter */
 260             trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
 261         }
 262     }
 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 char *trace_opt_parse(const char *optarg)
 289 {
 290     char *trace_file;
 291     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 292                                              optarg, true);
 293     if (!opts) {
 294         exit(1);
 295     }
 296     if (qemu_opt_get(opts, "enable")) {
 297         trace_enable_events(qemu_opt_get(opts, "enable"));
 298     }
 299     trace_init_events(qemu_opt_get(opts, "events"));
 300     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 301     qemu_opts_del(opts);
 302
 303     return trace_file;
 304 }
 305
 306 uint32_t trace_get_vcpu_event_count(void)
 307 {
 308     return next_vcpu_id;
 309 }