qemu/trace/control.c
Gerd Hoffmann 263b6e9644 trace/simple: add st_init_group
Add helper function and call it for each trace event group added.
Makes sure that events added at module load time are initialized
properly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20210601132414.432430-6-kraxel@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2021-07-12 17:37:07 +01:00

337 lines
8.4 KiB
C

/*
* Interface for configuring and controlling the state of tracing events.
*
* Copyright (C) 2011-2016 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 "qemu/osdep.h"
#include "trace/control.h"
#include "qemu/help_option.h"
#include "qemu/option.h"
#ifdef CONFIG_TRACE_SIMPLE
#include "trace/simple.h"
#endif
#ifdef CONFIG_TRACE_FTRACE
#include "trace/ftrace.h"
#endif
#ifdef CONFIG_TRACE_LOG
#include "qemu/log.h"
#endif
#ifdef CONFIG_TRACE_SYSLOG
#include <syslog.h>
#endif
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/config-file.h"
#include "monitor/monitor.h"
#include "trace/trace-root.h"
int trace_events_enabled_count;
typedef struct TraceEventGroup {
TraceEvent **events;
} TraceEventGroup;
static TraceEventGroup *event_groups;
static size_t nevent_groups;
static uint32_t next_id;
static uint32_t next_vcpu_id;
static bool init_trace_on_startup;
static char *trace_opts_file;
QemuOptsList qemu_trace_opts = {
.name = "trace",
.implied_opt_name = "enable",
.head = QTAILQ_HEAD_INITIALIZER(qemu_trace_opts.head),
.desc = {
{
.name = "enable",
.type = QEMU_OPT_STRING,
},
{
.name = "events",
.type = QEMU_OPT_STRING,
},{
.name = "file",
.type = QEMU_OPT_STRING,
},
{ /* end of list */ }
},
};
void trace_event_register_group(TraceEvent **events)
{
size_t i;
for (i = 0; events[i] != NULL; i++) {
events[i]->id = next_id++;
if (events[i]->vcpu_id == TRACE_VCPU_EVENT_NONE) {
continue;
}
if (likely(next_vcpu_id < CPU_TRACE_DSTATE_MAX_EVENTS)) {
events[i]->vcpu_id = next_vcpu_id++;
} else {
warn_report("too many vcpu trace events; dropping '%s'",
events[i]->name);
}
}
event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
event_groups[nevent_groups].events = events;
nevent_groups++;
#ifdef CONFIG_TRACE_SIMPLE
st_init_group(nevent_groups - 1);
#endif
}
TraceEvent *trace_event_name(const char *name)
{
assert(name != NULL);
TraceEventIter iter;
TraceEvent *ev;
trace_event_iter_init_all(&iter);
while ((ev = trace_event_iter_next(&iter)) != NULL) {
if (strcmp(trace_event_get_name(ev), name) == 0) {
return ev;
}
}
return NULL;
}
void trace_event_iter_init_all(TraceEventIter *iter)
{
iter->event = 0;
iter->group = 0;
iter->group_id = -1;
iter->pattern = NULL;
}
void trace_event_iter_init_pattern(TraceEventIter *iter, const char *pattern)
{
trace_event_iter_init_all(iter);
iter->pattern = pattern;
}
void trace_event_iter_init_group(TraceEventIter *iter, size_t group_id)
{
trace_event_iter_init_all(iter);
iter->group_id = group_id;
}
TraceEvent *trace_event_iter_next(TraceEventIter *iter)
{
while (iter->group < nevent_groups &&
event_groups[iter->group].events[iter->event] != NULL) {
TraceEvent *ev = event_groups[iter->group].events[iter->event];
size_t group = iter->group;
iter->event++;
if (event_groups[iter->group].events[iter->event] == NULL) {
iter->event = 0;
iter->group++;
}
if (iter->pattern &&
!g_pattern_match_simple(iter->pattern, trace_event_get_name(ev))) {
continue;
}
if (iter->group_id != -1 &&
iter->group_id != group) {
continue;
}
return ev;
}
return NULL;
}
void trace_list_events(FILE *f)
{
TraceEventIter iter;
TraceEvent *ev;
trace_event_iter_init_all(&iter);
while ((ev = trace_event_iter_next(&iter)) != NULL) {
fprintf(f, "%s\n", trace_event_get_name(ev));
}
#ifdef CONFIG_TRACE_DTRACE
fprintf(f, "This list of names of trace points may be incomplete "
"when using the DTrace/SystemTap backends.\n"
"Run 'qemu-trace-stap list %s' to print the full list.\n",
error_get_progname());
#endif
}
static void do_trace_enable_events(const char *line_buf)
{
const bool enable = ('-' != line_buf[0]);
const char *line_ptr = enable ? line_buf : line_buf + 1;
TraceEventIter iter;
TraceEvent *ev;
bool is_pattern = trace_event_is_pattern(line_ptr);
trace_event_iter_init_pattern(&iter, line_ptr);
while ((ev = trace_event_iter_next(&iter)) != NULL) {
if (!trace_event_get_state_static(ev)) {
if (!is_pattern) {
warn_report("trace event '%s' is not traceable",
line_ptr);
return;
}
continue;
}
/* start tracing */
trace_event_set_state_dynamic(ev, enable);
if (!is_pattern) {
return;
}
}
if (!is_pattern) {
warn_report("trace event '%s' does not exist",
line_ptr);
}
}
void trace_enable_events(const char *line_buf)
{
if (is_help_option(line_buf)) {
trace_list_events(stdout);
if (monitor_cur() == NULL) {
exit(0);
}
} else {
do_trace_enable_events(line_buf);
}
}
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;
}
trace_enable_events(line_buf);
}
}
if (fclose(fp) != 0) {
loc_set_file(fname, 0);
error_report("%s", strerror(errno));
exit(1);
}
loc_pop(&loc);
}
void trace_init_file(void)
{
#ifdef CONFIG_TRACE_SIMPLE
st_set_trace_file(trace_opts_file);
if (init_trace_on_startup) {
st_set_trace_file_enabled(true);
}
#elif defined CONFIG_TRACE_LOG
/*
* If both the simple and the log backends are enabled, "--trace file"
* only applies to the simple backend; use "-D" for the log
* backend. However we should only override -D if we actually have
* something to override it with.
*/
if (trace_opts_file) {
qemu_set_log_filename(trace_opts_file, &error_fatal);
}
#else
if (trace_opts_file) {
fprintf(stderr, "error: --trace file=...: "
"option not supported by the selected tracing backends\n");
exit(1);
}
#endif
}
void trace_fini_vcpu(CPUState *vcpu)
{
TraceEventIter iter;
TraceEvent *ev;
trace_guest_cpu_exit(vcpu);
trace_event_iter_init_all(&iter);
while ((ev = trace_event_iter_next(&iter)) != NULL) {
if (trace_event_is_vcpu(ev) &&
trace_event_get_state_static(ev) &&
trace_event_get_vcpu_state_dynamic(vcpu, ev)) {
/* must disable to affect the global counter */
trace_event_set_vcpu_state_dynamic(vcpu, ev, false);
}
}
}
bool trace_init_backends(void)
{
#ifdef CONFIG_TRACE_SIMPLE
if (!st_init()) {
fprintf(stderr, "failed to initialize simple tracing backend.\n");
return false;
}
#endif
#ifdef CONFIG_TRACE_FTRACE
if (!ftrace_init()) {
fprintf(stderr, "failed to initialize ftrace backend.\n");
return false;
}
#endif
#ifdef CONFIG_TRACE_SYSLOG
openlog(NULL, LOG_PID, LOG_DAEMON);
#endif
return true;
}
void trace_opt_parse(const char *optarg)
{
QemuOpts *opts = qemu_opts_parse_noisily(qemu_find_opts("trace"),
optarg, true);
if (!opts) {
exit(1);
}
if (qemu_opt_get(opts, "enable")) {
trace_enable_events(qemu_opt_get(opts, "enable"));
}
trace_init_events(qemu_opt_get(opts, "events"));
init_trace_on_startup = true;
g_free(trace_opts_file);
trace_opts_file = g_strdup(qemu_opt_get(opts, "file"));
qemu_opts_del(opts);
}
uint32_t trace_get_vcpu_event_count(void)
{
return next_vcpu_id;
}