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 "trace/control.h"
  11 #ifdef CONFIG_TRACE_SIMPLE
  12 #include "trace/simple.h"
  13 #endif
  14 #ifdef CONFIG_TRACE_FTRACE
  15 #include "trace/ftrace.h"
  16 #endif
  17 #include "qemu/error-report.h"
  18
  19 TraceEvent *trace_event_name(const char *name)
  20 {
  21     assert(name != NULL);
  22
  23     TraceEventID i;
  24     for (i = 0; i < trace_event_count(); i++) {
  25         TraceEvent *ev = trace_event_id(i);
  26         if (strcmp(trace_event_get_name(ev), name) == 0) {
  27             return ev;
  28         }
  29     }
  30     return NULL;
  31 }
  32
  33 static bool pattern_glob(const char *pat, const char *ev)
  34 {
  35     while (*pat != '\0' && *ev != '\0') {
  36         if (*pat == *ev) {
  37             pat++;
  38             ev++;
  39         }
  40         else if (*pat == '*') {
  41             if (pattern_glob(pat, ev+1)) {
  42                 return true;
  43             } else if (pattern_glob(pat+1, ev)) {
  44                 return true;
  45             } else {
  46                 return false;
  47             }
  48         } else {
  49             return false;
  50         }
  51     }
  52
  53     while (*pat == '*') {
  54         pat++;
  55     }
  56
  57     if (*pat == '\0' && *ev == '\0') {
  58         return true;
  59     } else {
  60         return false;
  61     }
  62 }
  63
  64 TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
  65 {
  66     assert(pat != NULL);
  67
  68     TraceEventID i;
  69
  70     if (ev == NULL) {
  71         i = -1;
  72     } else {
  73         i = trace_event_get_id(ev);
  74     }
  75     i++;
  76
  77     while (i < trace_event_count()) {
  78         TraceEvent *res = trace_event_id(i);
  79         if (pattern_glob(pat, trace_event_get_name(res))) {
  80             return res;
  81         }
  82         i++;
  83     }
  84
  85     return NULL;
  86 }
  87
  88 static void trace_init_events(const char *fname)
  89 {
  90     Location loc;
  91     FILE *fp;
  92     char line_buf[1024];
  93     size_t line_idx = 0;
  94
  95     if (fname == NULL) {
  96         return;
  97     }
  98
  99     loc_push_none(&loc);
 100     loc_set_file(fname, 0);
 101     fp = fopen(fname, "r");
 102     if (!fp) {
 103         error_report("%s", strerror(errno));
 104         exit(1);
 105     }
 106     while (fgets(line_buf, sizeof(line_buf), fp)) {
 107         loc_set_file(fname, ++line_idx);
 108         size_t len = strlen(line_buf);
 109         if (len > 1) {              /* skip empty lines */
 110             line_buf[len - 1] = '\0';
 111             if ('#' == line_buf[0]) { /* skip commented lines */
 112                 continue;
 113             }
 114             const bool enable = ('-' != line_buf[0]);
 115             char *line_ptr = enable ? line_buf : line_buf + 1;
 116             if (trace_event_is_pattern(line_ptr)) {
 117                 TraceEvent *ev = NULL;
 118                 while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
 119                     if (trace_event_get_state_static(ev)) {
 120                         trace_event_set_state_dynamic(ev, enable);
 121                     }
 122                 }
 123             } else {
 124                 TraceEvent *ev = trace_event_name(line_ptr);
 125                 if (ev == NULL) {
 126                     error_report("WARNING: trace event '%s' does not exist",
 127                                  line_ptr);
 128                 } else if (!trace_event_get_state_static(ev)) {
 129                     error_report("WARNING: trace event '%s' is not traceable\n",
 130                                  line_ptr);
 131                 } else {
 132                     trace_event_set_state_dynamic(ev, enable);
 133                 }
 134             }
 135         }
 136     }
 137     if (fclose(fp) != 0) {
 138         loc_set_file(fname, 0);
 139         error_report("%s", strerror(errno));
 140         exit(1);
 141     }
 142     loc_pop(&loc);
 143 }
 144
 145 bool trace_init_backends(const char *events, const char *file)
 146 {
 147 #ifdef CONFIG_TRACE_SIMPLE
 148     if (!st_init(file)) {
 149         fprintf(stderr, "failed to initialize simple tracing backend.\n");
 150         return false;
 151     }
 152 #else
 153     if (file) {
 154         fprintf(stderr, "error: -trace file=...: "
 155                 "option not supported by the selected tracing backends\n");
 156         return false;
 157     }
 158 #endif
 159
 160 #ifdef CONFIG_TRACE_FTRACE
 161     if (!ftrace_init()) {
 162         fprintf(stderr, "failed to initialize ftrace backend.\n");
 163         return false;
 164     }
 165 #endif
 166
 167     trace_init_events(events);
 168     return true;
 169 }