qemu/trace/control.c

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/*
* Interface for configuring and controlling the state of tracing events.
*
* Copyright (C) 2011-2014 Lluís Vilanova <vilanova@ac.upc.edu>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "trace/control.h"
#ifdef CONFIG_TRACE_SIMPLE
#include "trace/simple.h"
#endif
#ifdef CONFIG_TRACE_FTRACE
#include "trace/ftrace.h"
#endif
#include "qemu/error-report.h"
TraceEvent *trace_event_name(const char *name)
{
assert(name != NULL);
TraceEventID i;
for (i = 0; i < trace_event_count(); i++) {
TraceEvent *ev = trace_event_id(i);
if (strcmp(trace_event_get_name(ev), name) == 0) {
return ev;
}
}
return NULL;
}
static bool pattern_glob(const char *pat, const char *ev)
{
while (*pat != '\0' && *ev != '\0') {
if (*pat == *ev) {
pat++;
ev++;
}
else if (*pat == '*') {
if (pattern_glob(pat, ev+1)) {
return true;
} else if (pattern_glob(pat+1, ev)) {
return true;
} else {
return false;
}
} else {
return false;
}
}
while (*pat == '*') {
pat++;
}
if (*pat == '\0' && *ev == '\0') {
return true;
} else {
return false;
}
}
TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
{
assert(pat != NULL);
TraceEventID i;
if (ev == NULL) {
i = -1;
} else {
i = trace_event_get_id(ev);
}
i++;
while (i < trace_event_count()) {
TraceEvent *res = trace_event_id(i);
if (pattern_glob(pat, trace_event_get_name(res))) {
return res;
}
i++;
}
return NULL;
}
static void trace_init_events(const char *fname)
{
Location loc;
FILE *fp;
char line_buf[1024];
size_t line_idx = 0;
if (fname == NULL) {
return;
}
loc_push_none(&loc);
loc_set_file(fname, 0);
fp = fopen(fname, "r");
if (!fp) {
error_report("%s", strerror(errno));
exit(1);
}
while (fgets(line_buf, sizeof(line_buf), fp)) {
loc_set_file(fname, ++line_idx);
size_t len = strlen(line_buf);
if (len > 1) { /* skip empty lines */
line_buf[len - 1] = '\0';
if ('#' == line_buf[0]) { /* skip commented lines */
continue;
}
const bool enable = ('-' != line_buf[0]);
char *line_ptr = enable ? line_buf : line_buf + 1;
if (trace_event_is_pattern(line_ptr)) {
TraceEvent *ev = NULL;
while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
if (trace_event_get_state_static(ev)) {
trace_event_set_state_dynamic(ev, enable);
}
}
} else {
TraceEvent *ev = trace_event_name(line_ptr);
if (ev == NULL) {
error_report("WARNING: trace event '%s' does not exist",
line_ptr);
} else if (!trace_event_get_state_static(ev)) {
error_report("WARNING: trace event '%s' is not traceable",
line_ptr);
} else {
trace_event_set_state_dynamic(ev, enable);
}
}
}
}
if (fclose(fp) != 0) {
loc_set_file(fname, 0);
error_report("%s", strerror(errno));
exit(1);
}
loc_pop(&loc);
}
bool trace_init_backends(const char *events, const char *file)
{
#ifdef CONFIG_TRACE_SIMPLE
if (!st_init(file)) {
fprintf(stderr, "failed to initialize simple tracing backend.\n");
return false;
}
#else
if (file) {
fprintf(stderr, "error: -trace file=...: "
"option not supported by the selected tracing backends\n");
return false;
}
#endif
#ifdef CONFIG_TRACE_FTRACE
if (!ftrace_init()) {
fprintf(stderr, "failed to initialize ftrace backend.\n");
return false;
}
#endif
trace_init_events(events);
return true;
}