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/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 #ifdef CONFIG_TRACE_SIMPLE
  87     st_init_group(nevent_groups - 1);
  88 #endif
  89 }
  90
  91
  92 TraceEvent *trace_event_name(const char *name)
  93 {
  94     assert(name != NULL);
  95
  96     TraceEventIter iter;
  97     TraceEvent *ev;
  98     trace_event_iter_init_all(&iter);
  99     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 100         if (strcmp(trace_event_get_name(ev), name) == 0) {
 101             return ev;
 102         }
 103     }
 104     return NULL;
 105 }
 106
 107 void trace_event_iter_init_all(TraceEventIter *iter)
 108 {
 109     iter->event = 0;
 110     iter->group = 0;
 111     iter->group_id = -1;
 112     iter->pattern = NULL;
 113 }
 114
 115 void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern)
 116 {
 117     trace_event_iter_init_all(iter);
 118     iter->pattern = pattern;
 119 }
 120
 121 void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id)
 122 {
 123     trace_event_iter_init_all(iter);
 124     iter->group_id = group_id;
 125 }
 126
 127 TraceEvent *trace_event_iter_next(TraceEventIter *iter)
 128 {
 129     while (iter->group < nevent_groups &&
 130            event_groups[iter->group].events[iter->event] != NULL) {
 131         TraceEvent *ev = event_groups[iter->group].events[iter->event];
 132         size_t group = iter->group;
 133         iter->event++;
 134         if (event_groups[iter->group].events[iter->event] == NULL) {
 135             iter->event = 0;
 136             iter->group++;
 137         }
 138         if (iter->pattern &&
 139             !g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
 140             continue;
 141         }
 142         if (iter->group_id != -1 &&
 143             iter->group_id != group) {
 144             continue;
 145         }
 146         return ev;
 147     }
 148
 149     return NULL;
 150 }
 151
 152 void trace_list_events(FILE *f)
 153 {
 154     TraceEventIter iter;
 155     TraceEvent *ev;
 156     trace_event_iter_init_all(&iter);
 157     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 158         fprintf(f, "%s\n", trace_event_get_name(ev));
 159     }
 160 #ifdef CONFIG_TRACE_DTRACE
 161     fprintf(f, "This list of names of trace points may be incomplete "
 162                "when using the DTrace/SystemTap backends.\n"
 163                "Run 'qemu-trace-stap list %s' to print the full list.\n",
 164             g_get_prgname());
 165 #endif
 166 }
 167
 168 static void do_trace_enable_events(const char *line_buf)
 169 {
 170     const bool enable = ('-' != line_buf[0]);
 171     const char *line_ptr = enable ? line_buf : line_buf + 1;
 172     TraceEventIter iter;
 173     TraceEvent *ev;
 174     bool is_pattern = trace_event_is_pattern(line_ptr);
 175
 176     trace_event_iter_init_pattern(&iter, line_ptr);
 177     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 178         if (!trace_event_get_state_static(ev)) {
 179             if (!is_pattern) {
 180                 warn_report("trace event '%s' is not traceable",
 181                             line_ptr);
 182                 return;
 183             }
 184             continue;
 185         }
 186
 187         /* start tracing */
 188         trace_event_set_state_dynamic(ev, enable);
 189         if (!is_pattern) {
 190             return;
 191         }
 192     }
 193
 194     if (!is_pattern) {
 195         warn_report("trace event '%s' does not exist",
 196                     line_ptr);
 197     }
 198 }
 199
 200 void trace_enable_events(const char *line_buf)
 201 {
 202     if (is_help_option(line_buf)) {
 203         trace_list_events(stdout);
 204         if (monitor_cur() == NULL) {
 205             exit(0);
 206         }
 207     } else {
 208         do_trace_enable_events(line_buf);
 209     }
 210 }
 211
 212 static void trace_init_events(const char *fname)
 213 {
 214     Location loc;
 215     FILE *fp;
 216     char line_buf[1024];
 217     size_t line_idx = 0;
 218
 219     if (fname == NULL) {
 220         return;
 221     }
 222
 223     loc_push_none(&loc);
 224     loc_set_file(fname, 0);
 225     fp = fopen(fname, "r");
 226     if (!fp) {
 227         error_report("%s", strerror(errno));
 228         exit(1);
 229     }
 230     while (fgets(line_buf, sizeof(line_buf), fp)) {
 231         loc_set_file(fname, ++line_idx);
 232         size_t len = strlen(line_buf);
 233         if (len > 1) {              /* skip empty lines */
 234             line_buf[len - 1] = '\0';
 235             if ('#' == line_buf[0]) { /* skip commented lines */
 236                 continue;
 237             }
 238             trace_enable_events(line_buf);
 239         }
 240     }
 241     if (fclose(fp) != 0) {
 242         loc_set_file(fname, 0);
 243         error_report("%s", strerror(errno));
 244         exit(1);
 245     }
 246     loc_pop(&loc);
 247 }
 248
 249 void trace_init_file(void)
 250 {
 251 #ifdef CONFIG_TRACE_SIMPLE
 252     st_set_trace_file(trace_opts_file);
 253     if (init_trace_on_startup) {
 254         st_set_trace_file_enabled(true);
 255     }
 256 #elif defined CONFIG_TRACE_LOG
 257     /*
 258      * If both the simple and the log backends are enabled, "--trace file"
 259      * only applies to the simple backend; use "-D" for the log
 260      * backend. However we should only override -D if we actually have
 261      * something to override it with.
 262      */
 263     if (trace_opts_file) {
 264         qemu_set_log_filename(trace_opts_file, &error_fatal);
 265     }
 266 #else
 267     if (trace_opts_file) {
 268         fprintf(stderr, "error: --trace file=...: "
 269                 "option not supported by the selected tracing backends\n");
 270         exit(1);
 271     }
 272 #endif
 273 }
 274
 275 void trace_fini_vcpu(CPUState *vcpu)
 276 {
 277     TraceEventIter iter;
 278     TraceEvent *ev;
 279
 280     trace_guest_cpu_exit(vcpu);
 281
 282     trace_event_iter_init_all(&iter);
 283     while ((ev = trace_event_iter_next(&iter)) != NULL) {
 284         if (trace_event_is_vcpu(ev) &&
 285             trace_event_get_state_static(ev) &&
 286             trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
 287             /* must disable to affect the global counter */
 288             trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
 289         }
 290     }
 291 }
 292
 293 bool trace_init_backends(void)
 294 {
 295 #ifdef CONFIG_TRACE_SIMPLE
 296     if (!st_init()) {
 297         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 298         return false;
 299     }
 300 #endif
 301
 302 #ifdef CONFIG_TRACE_FTRACE
 303     if (!ftrace_init()) {
 304         fprintf(stderr, "failed to initialize ftrace backend.\n");
 305         return false;
 306     }
 307 #endif
 308
 309 #ifdef CONFIG_TRACE_SYSLOG
 310     openlog(NULL, LOG_PID, LOG_DAEMON);
 311 #endif
 312
 313     return true;
 314 }
 315
 316 void trace_opt_parse(const char *optarg)
 317 {
 318     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 319                                              optarg, true);
 320     if (!opts) {
 321         exit(1);
 322     }
 323     if (qemu_opt_get(opts, "enable")) {
 324         trace_enable_events(qemu_opt_get(opts, "enable"));
 325     }
 326     trace_init_events(qemu_opt_get(opts, "events"));
 327     init_trace_on_startup = true;
 328     g_free(trace_opts_file);
 329     trace_opts_file = g_strdup(qemu_opt_get(opts, "file"));
 330     qemu_opts_del(opts);
 331 }
 332
 333 uint32_t trace_get_vcpu_event_count(void)
 334 {
 335     return next_vcpu_id;
 336 }