trace/control.c - qemu - Git at Google

 /*
  * 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-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;

 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++;
 }


 TraceEvent *trace_event_name(const char *name)
 {
     assert(name != NULL);

     TraceEventIter iter;
     TraceEvent *ev;
     trace_event_iter_init(&iter, NULL);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         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;
     }
 }


 void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
 {
     iter->event = 0;
     iter->group = 0;
     iter->pattern = pattern;
 }

 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];
         iter->event++;
         if (event_groups[iter->group].events[iter->event] == NULL) {
             iter->event = 0;
             iter->group++;
         }
         if (!iter->pattern ||
             pattern_glob(iter->pattern,
                          trace_event_get_name(ev))) {
             return ev;
         }
     }

     return NULL;
 }

 void trace_list_events(void)
 {
     TraceEventIter iter;
     TraceEvent *ev;
     trace_event_iter_init(&iter, NULL);
     while ((ev = trace_event_iter_next(&iter)) != NULL) {
         fprintf(stderr, "%s\n", trace_event_get_name(ev));
     }
 }

 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(&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();
         if (cur_mon == 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(const char *file)
 {
 #ifdef CONFIG_TRACE_SIMPLE
     st_set_trace_file(file);
 #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.
      */
     if (file) {
         qemu_set_log_filename(file, &error_fatal);
     }
 #else
     if (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(&iter, NULL);
     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;
 }

 char *trace_opt_parse(const char *optarg)
 {
     char *trace_file;
     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"));
     trace_file = g_strdup(qemu_opt_get(opts, "file"));
     qemu_opts_del(opts);

     return trace_file;
 }

 uint32_t trace_get_vcpu_event_count(void)
 {
     return next_vcpu_id;
 }
	/*
	* 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-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;

	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++;
	}


	TraceEvent trace_event_name(const char name)
	{
	assert(name != NULL);

	TraceEventIter iter;
	TraceEvent *ev;
	trace_event_iter_init(&iter, NULL);
	while ((ev = trace_event_iter_next(&iter)) != NULL) {
	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;
	}
	}


	void trace_event_iter_init(TraceEventIter iter, const char pattern)
	{
	iter->event = 0;
	iter->group = 0;
	iter->pattern = pattern;
	}

	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];
	iter->event++;
	if (event_groups[iter->group].events[iter->event] == NULL) {
	iter->event = 0;
	iter->group++;
	}
	if (!iter->pattern \|\|
	pattern_glob(iter->pattern,
	trace_event_get_name(ev))) {
	return ev;
	}
	}

	return NULL;
	}

	void trace_list_events(void)
	{
	TraceEventIter iter;
	TraceEvent *ev;
	trace_event_iter_init(&iter, NULL);
	while ((ev = trace_event_iter_next(&iter)) != NULL) {
	fprintf(stderr, "%s\n", trace_event_get_name(ev));
	}
	}

	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(&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();
	if (cur_mon == 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(const char *file)
	{
	#ifdef CONFIG_TRACE_SIMPLE
	st_set_trace_file(file);
	#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.
	*/
	if (file) {
	qemu_set_log_filename(file, &error_fatal);
	}
	#else
	if (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(&iter, NULL);
	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;
	}

	char trace_opt_parse(const char optarg)
	{
	char *trace_file;
	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"));
	trace_file = g_strdup(qemu_opt_get(opts, "file"));
	qemu_opts_del(opts);

	return trace_file;
	}

	uint32_t trace_get_vcpu_event_count(void)
	{
	return next_vcpu_id;
	}