trace/control.c

   1 /*
   2  * Interface for configuring and controlling the state of tracing events.
   3  *
   4  * Copyright (C) 2011-2014 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 bool trace_events_dstate[TRACE_EVENT_COUNT];
  29
  30 QemuOptsList qemu_trace_opts = {
  31     .name = "trace",
  32     .implied_opt_name = "enable",
  33     .head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
  34     .desc = {
  35         {
  36             .name = "enable",
  37             .type = QEMU_OPT_STRING,
  38         },
  39         {
  40             .name = "events",
  41             .type = QEMU_OPT_STRING,
  42         },{
  43             .name = "file",
  44             .type = QEMU_OPT_STRING,
  45         },
  46         { /* end of list */ }
  47     },
  48 };
  49
  50
  51 TraceEvent *trace_event_name(const char *name)
  52 {
  53     assert(name != NULL);
  54
  55     TraceEventID i;
  56     for (i = 0; i < trace_event_count(); i++) {
  57         TraceEvent *ev = trace_event_id(i);
  58         if (strcmp(trace_event_get_name(ev), name) == 0) {
  59             return ev;
  60         }
  61     }
  62     return NULL;
  63 }
  64
  65 static bool pattern_glob(const char *pat, const char *ev)
  66 {
  67     while (*pat != '\0' && *ev != '\0') {
  68         if (*pat == *ev) {
  69             pat++;
  70             ev++;
  71         }
  72         else if (*pat == '*') {
  73             if (pattern_glob(pat, ev+1)) {
  74                 return true;
  75             } else if (pattern_glob(pat+1, ev)) {
  76                 return true;
  77             } else {
  78                 return false;
  79             }
  80         } else {
  81             return false;
  82         }
  83     }
  84
  85     while (*pat == '*') {
  86         pat++;
  87     }
  88
  89     if (*pat == '\0' && *ev == '\0') {
  90         return true;
  91     } else {
  92         return false;
  93     }
  94 }
  95
  96 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
  97 {
  98     assert(pat != NULL);
  99
 100     TraceEventID i;
 101
 102     if (ev == NULL) {
 103         i = -1;
 104     } else {
 105         i = trace_event_get_id(ev);
 106     }
 107     i++;
 108
 109     while (i < trace_event_count()) {
 110         TraceEvent *res = trace_event_id(i);
 111         if (pattern_glob(pat, trace_event_get_name(res))) {
 112             return res;
 113         }
 114         i++;
 115     }
 116
 117     return NULL;
 118 }
 119
 120 void trace_list_events(void)
 121 {
 122     int i;
 123     for (i = 0; i < trace_event_count(); i++) {
 124         TraceEvent *res = trace_event_id(i);
 125         fprintf(stderr, "%s\n", trace_event_get_name(res));
 126     }
 127 }
 128
 129 static void do_trace_enable_events(const char *line_buf)
 130 {
 131     const bool enable = ('-' != line_buf[0]);
 132     const char *line_ptr = enable ? line_buf : line_buf + 1;
 133
 134     if (trace_event_is_pattern(line_ptr)) {
 135         TraceEvent *ev = NULL;
 136         while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 137             if (trace_event_get_state_static(ev)) {
 138                 trace_event_set_state_dynamic(ev, enable);
 139             }
 140         }
 141     } else {
 142         TraceEvent *ev = trace_event_name(line_ptr);
 143         if (ev == NULL) {
 144             error_report("WARNING: trace event '%s' does not exist",
 145                          line_ptr);
 146         } else if (!trace_event_get_state_static(ev)) {
 147             error_report("WARNING: trace event '%s' is not traceable",
 148                          line_ptr);
 149         } else {
 150             trace_event_set_state_dynamic(ev, enable);
 151         }
 152     }
 153 }
 154
 155 void trace_enable_events(const char *line_buf)
 156 {
 157     if (is_help_option(line_buf)) {
 158         trace_list_events();
 159         if (cur_mon == NULL) {
 160             exit(0);
 161         }
 162     } else {
 163         do_trace_enable_events(line_buf);
 164     }
 165 }
 166
 167 static void trace_init_events(const char *fname)
 168 {
 169     Location loc;
 170     FILE *fp;
 171     char line_buf[1024];
 172     size_t line_idx = 0;
 173
 174     if (fname == NULL) {
 175         return;
 176     }
 177
 178     loc_push_none(&loc);
 179     loc_set_file(fname, 0);
 180     fp = fopen(fname, "r");
 181     if (!fp) {
 182         error_report("%s", strerror(errno));
 183         exit(1);
 184     }
 185     while (fgets(line_buf, sizeof(line_buf), fp)) {
 186         loc_set_file(fname, ++line_idx);
 187         size_t len = strlen(line_buf);
 188         if (len > 1) {              /* skip empty lines */
 189             line_buf[len - 1] = '\0';
 190             if ('#' == line_buf[0]) { /* skip commented lines */
 191                 continue;
 192             }
 193             trace_enable_events(line_buf);
 194         }
 195     }
 196     if (fclose(fp) != 0) {
 197         loc_set_file(fname, 0);
 198         error_report("%s", strerror(errno));
 199         exit(1);
 200     }
 201     loc_pop(&loc);
 202 }
 203
 204 void trace_init_file(const char *file)
 205 {
 206 #ifdef CONFIG_TRACE_SIMPLE
 207     st_set_trace_file(file);
 208 #elif defined CONFIG_TRACE_LOG
 209     /* If both the simple and the log backends are enabled, "-trace file"
 210      * only applies to the simple backend; use "-D" for the log backend.
 211      */
 212     if (file) {
 213         qemu_set_log_filename(file, &error_fatal);
 214     }
 215 #else
 216     if (file) {
 217         fprintf(stderr, "error: -trace file=...: "
 218                 "option not supported by the selected tracing backends\n");
 219         exit(1);
 220     }
 221 #endif
 222 }
 223
 224 bool trace_init_backends(void)
 225 {
 226 #ifdef CONFIG_TRACE_SIMPLE
 227     if (!st_init()) {
 228         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 229         return false;
 230     }
 231 #endif
 232
 233 #ifdef CONFIG_TRACE_FTRACE
 234     if (!ftrace_init()) {
 235         fprintf(stderr, "failed to initialize ftrace backend.\n");
 236         return false;
 237     }
 238 #endif
 239
 240     return true;
 241 }
 242
 243 char *trace_opt_parse(const char *optarg)
 244 {
 245     char *trace_file;
 246     QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
 247                                              optarg, true);
 248     if (!opts) {
 249         exit(1);
 250     }
 251     if (qemu_opt_get(opts, "enable")) {
 252         trace_enable_events(qemu_opt_get(opts, "enable"));
 253     }
 254     trace_init_events(qemu_opt_get(opts, "events"));
 255     trace_file = g_strdup(qemu_opt_get(opts, "file"));
 256     qemu_opts_del(opts);
 257
 258     return trace_file;
 259 }