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     }
  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 }