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 "monitor/monitor.h"
  25
  26 int trace_events_enabled_count;
  27 bool trace_events_dstate[TRACE_EVENT_COUNT];
  28
  29 TraceEvent *trace_event_name(const char *name)
  30 {
  31     assert(name != NULL);
  32
  33     TraceEventID i;
  34     for (i = 0; i < trace_event_count(); i++) {
  35         TraceEvent *ev = trace_event_id(i);
  36         if (strcmp(trace_event_get_name(ev), name) == 0) {
  37             return ev;
  38         }
  39     }
  40     return NULL;
  41 }
  42
  43 static bool pattern_glob(const char *pat, const char *ev)
  44 {
  45     while (*pat != '\0' && *ev != '\0') {
  46         if (*pat == *ev) {
  47             pat++;
  48             ev++;
  49         }
  50         else if (*pat == '*') {
  51             if (pattern_glob(pat, ev+1)) {
  52                 return true;
  53             } else if (pattern_glob(pat+1, ev)) {
  54                 return true;
  55             } else {
  56                 return false;
  57             }
  58         } else {
  59             return false;
  60         }
  61     }
  62
  63     while (*pat == '*') {
  64         pat++;
  65     }
  66
  67     if (*pat == '\0' && *ev == '\0') {
  68         return true;
  69     } else {
  70         return false;
  71     }
  72 }
  73
  74 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
  75 {
  76     assert(pat != NULL);
  77
  78     TraceEventID i;
  79
  80     if (ev == NULL) {
  81         i = -1;
  82     } else {
  83         i = trace_event_get_id(ev);
  84     }
  85     i++;
  86
  87     while (i < trace_event_count()) {
  88         TraceEvent *res = trace_event_id(i);
  89         if (pattern_glob(pat, trace_event_get_name(res))) {
  90             return res;
  91         }
  92         i++;
  93     }
  94
  95     return NULL;
  96 }
  97
  98 void trace_list_events(void)
  99 {
 100     int i;
 101     for (i = 0; i < trace_event_count(); i++) {
 102         TraceEvent *res = trace_event_id(i);
 103         fprintf(stderr, "%s\n", trace_event_get_name(res));
 104     }
 105 }
 106
 107 static void do_trace_enable_events(const char *line_buf)
 108 {
 109     const bool enable = ('-' != line_buf[0]);
 110     const char *line_ptr = enable ? line_buf : line_buf + 1;
 111
 112     if (trace_event_is_pattern(line_ptr)) {
 113         TraceEvent *ev = NULL;
 114         while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 115             if (trace_event_get_state_static(ev)) {
 116                 trace_event_set_state_dynamic(ev, enable);
 117             }
 118         }
 119     } else {
 120         TraceEvent *ev = trace_event_name(line_ptr);
 121         if (ev == NULL) {
 122             error_report("WARNING: trace event '%s' does not exist",
 123                          line_ptr);
 124         } else if (!trace_event_get_state_static(ev)) {
 125             error_report("WARNING: trace event '%s' is not traceable",
 126                          line_ptr);
 127         } else {
 128             trace_event_set_state_dynamic(ev, enable);
 129         }
 130     }
 131 }
 132
 133 void trace_enable_events(const char *line_buf)
 134 {
 135     if (is_help_option(line_buf)) {
 136         trace_list_events();
 137         if (cur_mon == NULL) {
 138             exit(0);
 139         }
 140     } else {
 141         do_trace_enable_events(line_buf);
 142     }
 143 }
 144
 145 void trace_init_events(const char *fname)
 146 {
 147     Location loc;
 148     FILE *fp;
 149     char line_buf[1024];
 150     size_t line_idx = 0;
 151
 152     if (fname == NULL) {
 153         return;
 154     }
 155
 156     loc_push_none(&loc);
 157     loc_set_file(fname, 0);
 158     fp = fopen(fname, "r");
 159     if (!fp) {
 160         error_report("%s", strerror(errno));
 161         exit(1);
 162     }
 163     while (fgets(line_buf, sizeof(line_buf), fp)) {
 164         loc_set_file(fname, ++line_idx);
 165         size_t len = strlen(line_buf);
 166         if (len > 1) {              /* skip empty lines */
 167             line_buf[len - 1] = '\0';
 168             if ('#' == line_buf[0]) { /* skip commented lines */
 169                 continue;
 170             }
 171             trace_enable_events(line_buf);
 172         }
 173     }
 174     if (fclose(fp) != 0) {
 175         loc_set_file(fname, 0);
 176         error_report("%s", strerror(errno));
 177         exit(1);
 178     }
 179     loc_pop(&loc);
 180 }
 181
 182 void trace_init_file(const char *file)
 183 {
 184 #ifdef CONFIG_TRACE_SIMPLE
 185     st_set_trace_file(file);
 186 #elif defined CONFIG_TRACE_LOG
 187     /* If both the simple and the log backends are enabled, "-trace file"
 188      * only applies to the simple backend; use "-D" for the log backend.
 189      */
 190     if (file) {
 191         qemu_set_log_filename(file, &error_fatal);
 192     }
 193 #else
 194     if (file) {
 195         fprintf(stderr, "error: -trace file=...: "
 196                 "option not supported by the selected tracing backends\n");
 197         exit(1);
 198     }
 199 #endif
 200 }
 201
 202 bool trace_init_backends(void)
 203 {
 204 #ifdef CONFIG_TRACE_SIMPLE
 205     if (!st_init()) {
 206         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 207         return false;
 208     }
 209 #endif
 210
 211 #ifdef CONFIG_TRACE_FTRACE
 212     if (!ftrace_init()) {
 213         fprintf(stderr, "failed to initialize ftrace backend.\n");
 214         return false;
 215     }
 216 #endif
 217
 218     return true;
 219 }