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 #ifdef CONFIG_TRACE_SIMPLE
  14 #include "trace/simple.h"
  15 #endif
  16 #ifdef CONFIG_TRACE_FTRACE
  17 #include "trace/ftrace.h"
  18 #endif
  19 #ifdef CONFIG_TRACE_LOG
  20 #include "qemu/log.h"
  21 #endif
  22 #ifdef CONFIG_TRACE_SYSLOG
  23 #include <syslog.h>
  24 #endif
  25 #include "qapi/error.h"
  26 #include "qemu/error-report.h"
  27 #include "qemu/config-file.h"
  28 #include "monitor/monitor.h"
  29
  30 int trace_events_enabled_count;
  31 /*
  32  * Interpretation depends on wether the event has the 'vcpu' property:
  33  * - false: Boolean value indicating whether the event is active.
  34  * - true : Integral counting the number of vCPUs that have this event enabled.
  35  */
  36 uint16_t trace_events_dstate[TRACE_EVENT_COUNT];
  37
  38 QemuOptsList qemu_trace_opts = {
  39     .name = "trace",
  40     .implied_opt_name = "enable",
  41     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
  42     .desc = {
  43         {
  44             .name = "enable",
  45             .type = QEMU_OPT_STRING,
  46         },
  47         {
  48             .name = "events",
  49             .type = QEMU_OPT_STRING,
  50         },{
  51             .name = "file",
  52             .type = QEMU_OPT_STRING,
  53         },
  54         { /* end of list */ }
  55     },
  56 };
  57
  58
  59 TraceEvent *trace_event_name(const char *name)
  60 {
  61     assert(name != NULL);
  62
  63     TraceEventID i;
  64     for (i = 0; i < trace_event_count(); i++) {
  65         TraceEvent *ev = trace_event_id(i);
  66         if (strcmp(trace_event_get_name(ev), name) == 0) {
  67             return ev;
  68         }
  69     }
  70     return NULL;
  71 }
  72
  73 static bool pattern_glob(const char *pat, const char *ev)
  74 {
  75     while (*pat != '\0' && *ev != '\0') {
  76         if (*pat == *ev) {
  77             pat++;
  78             ev++;
  79         }
  80         else if (*pat == '*') {
  81             if (pattern_glob(pat, ev+1)) {
  82                 return true;
  83             } else if (pattern_glob(pat+1, ev)) {
  84                 return true;
  85             } else {
  86                 return false;
  87             }
  88         } else {
  89             return false;
  90         }
  91     }
  92
  93     while (*pat == '*') {
  94         pat++;
  95     }
  96
  97     if (*pat == '\0' && *ev == '\0') {
  98         return true;
  99     } else {
 100         return false;
 101     }
 102 }
 103
 104 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
 105 {
 106     assert(pat != NULL);
 107
 108     TraceEventID i;
 109
 110     if (ev == NULL) {
 111         i = -1;
 112     } else {
 113         i = trace_event_get_id(ev);
 114     }
 115     i++;
 116
 117     while (i < trace_event_count()) {
 118         TraceEvent *res = trace_event_id(i);
 119         if (pattern_glob(pat, trace_event_get_name(res))) {
 120             return res;
 121         }
 122         i++;
 123     }
 124
 125     return NULL;
 126 }
 127
 128 void trace_list_events(void)
 129 {
 130     int i;
 131     for (i = 0; i < trace_event_count(); i++) {
 132         TraceEvent *res = trace_event_id(i);
 133         fprintf(stderr, "%s\n", trace_event_get_name(res));
 134     }
 135 }
 136
 137 static void do_trace_enable_events(const char *line_buf)
 138 {
 139     const bool enable = ('-' != line_buf[0]);
 140     const char *line_ptr = enable ? line_buf : line_buf + 1;
 141
 142     if (trace_event_is_pattern(line_ptr)) {
 143         TraceEvent *ev = NULL;
 144         while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 145             if (trace_event_get_state_static(ev)) {
 146                 trace_event_set_state_dynamic_init(ev, enable);
 147             }
 148         }
 149     } else {
 150         TraceEvent *ev = trace_event_name(line_ptr);
 151         if (ev == NULL) {
 152             error_report("WARNING: trace event '%s' does not exist",
 153                          line_ptr);
 154         } else if (!trace_event_get_state_static(ev)) {
 155             error_report("WARNING: trace event '%s' is not traceable",
 156                          line_ptr);
 157         } else {
 158             trace_event_set_state_dynamic_init(ev, enable);
 159         }
 160     }
 161 }
 162
 163 void trace_enable_events(const char *line_buf)
 164 {
 165     if (is_help_option(line_buf)) {
 166         trace_list_events();
 167         if (cur_mon == NULL) {
 168             exit(0);
 169         }
 170     } else {
 171         do_trace_enable_events(line_buf);
 172     }
 173 }
 174
 175 static void trace_init_events(const char *fname)
 176 {
 177     Location loc;
 178     FILE *fp;
 179     char line_buf[1024];
 180     size_t line_idx = 0;
 181
 182     if (fname == NULL) {
 183         return;
 184     }
 185
 186     loc_push_none(&loc);
 187     loc_set_file(fname, 0);
 188     fp = fopen(fname, "r");
 189     if (!fp) {
 190         error_report("%s", strerror(errno));
 191         exit(1);
 192     }
 193     while (fgets(line_buf, sizeof(line_buf), fp)) {
 194         loc_set_file(fname, ++line_idx);
 195         size_t len = strlen(line_buf);
 196         if (len > 1) {              /* skip empty lines */
 197             line_buf[len - 1] = '\0';
 198             if ('#' == line_buf[0]) { /* skip commented lines */
 199                 continue;
 200             }
 201             trace_enable_events(line_buf);
 202         }
 203     }
 204     if (fclose(fp) != 0) {
 205         loc_set_file(fname, 0);
 206         error_report("%s", strerror(errno));
 207         exit(1);
 208     }
 209     loc_pop(&loc);
 210 }
 211
 212 void trace_init_file(const char *file)
 213 {
 214 #ifdef CONFIG_TRACE_SIMPLE
 215     st_set_trace_file(file);
 216 #elif defined CONFIG_TRACE_LOG
 217     /* If both the simple and the log backends are enabled, "-trace file"
 218      * only applies to the simple backend; use "-D" for the log backend.
 219      */
 220     if (file) {
 221         qemu_set_log_filename(file, &error_fatal);
 222     }
 223 #else
 224     if (file) {
 225         fprintf(stderr, "error: -trace file=...: "
 226                 "option not supported by the selected tracing backends\n");
 227         exit(1);
 228     }
 229 #endif
 230 }
 231
 232 bool trace_init_backends(void)
 233 {
 234 #ifdef CONFIG_TRACE_SIMPLE
 235     if (!st_init()) {
 236         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 237         return false;
 238     }
 239 #endif
 240
 241 #ifdef CONFIG_TRACE_FTRACE
 242     if (!ftrace_init()) {
 243         fprintf(stderr, "failed to initialize ftrace backend.\n");
 244         return false;
 245     }
 246 #endif
 247
 248 #ifdef CONFIG_TRACE_SYSLOG
 249     openlog(NULL, LOG_PID, LOG_DAEMON);
 250 #endif
 251
 252     return true;
 253 }
 254
 255 char *trace_opt_parse(const char *optarg)
 256 {
 257     char *trace_file;
 258     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 259                                              optarg, true);
 260     if (!opts) {
 261         exit(1);
 262     }
 263     if (qemu_opt_get(opts, "enable")) {
 264         trace_enable_events(qemu_opt_get(opts, "enable"));
 265     }
 266     trace_init_events(qemu_opt_get(opts, "events"));
 267     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 268     qemu_opts_del(opts);
 269
 270     return trace_file;
 271 }
 272
 273 void trace_init_vcpu_events(void)
 274 {
 275     TraceEvent *ev = NULL;
 276     while ((ev = trace_event_pattern("*", ev)) != NULL) {
 277         if (trace_event_is_vcpu(ev) &&
 278             trace_event_get_state_static(ev) &&
 279             trace_event_get_state_dynamic(ev)) {
 280             TraceEventID id = trace_event_get_id(ev);
 281             /* check preconditions */
 282             assert(trace_events_dstate[id] == 1);
 283             /* disable early-init state ... */
 284             trace_events_dstate[id] = 0;
 285             trace_events_enabled_count--;
 286             /* ... and properly re-enable */
 287             trace_event_set_state_dynamic(ev, true);
 288         }
 289     }
 290 }