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