tools/perf/util/scripting-engines/trace-event-perl.c - fp2-dev/kernel/msm - Gitiles

 /*
  * trace-event-perl.  Feed perf trace events to an embedded Perl interpreter.
  *
  * Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
  *  the Free Software Foundation; either version 2 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  *
  */

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
 #include <errno.h>

 #include "../../perf.h"
 #include "../util.h"
 #include "../trace-event.h"

 #include <EXTERN.h>
 #include <perl.h>

 void boot_Perf__Trace__Context(pTHX_ CV *cv);
 void boot_DynaLoader(pTHX_ CV *cv);
 typedef PerlInterpreter * INTERP;

 void xs_init(pTHX);

 void xs_init(pTHX)
 {
 	const char *file = __FILE__;
 	dXSUB_SYS;

 	newXS("Perf::Trace::Context::bootstrap", boot_Perf__Trace__Context,
 	      file);
 	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
 }

 INTERP my_perl;

 #define FTRACE_MAX_EVENT				\
 	((1 << (sizeof(unsigned short) * 8)) - 1)

 struct event *events[FTRACE_MAX_EVENT];

 extern struct scripting_context *scripting_context;

 static char *cur_field_name;
 static int zero_flag_atom;

 static void define_symbolic_value(const char *ev_name,
 				  const char *field_name,
 				  const char *field_value,
 				  const char *field_str)
 {
 	unsigned long long value;
 	dSP;

 	value = eval_flag(field_value);

 	ENTER;
 	SAVETMPS;
 	PUSHMARK(SP);

 	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
 	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
 	XPUSHs(sv_2mortal(newSVuv(value)));
 	XPUSHs(sv_2mortal(newSVpv(field_str, 0)));

 	PUTBACK;
 	if (get_cv("main::define_symbolic_value", 0))
 		call_pv("main::define_symbolic_value", G_SCALAR);
 	SPAGAIN;
 	PUTBACK;
 	FREETMPS;
 	LEAVE;
 }

 static void define_symbolic_values(struct print_flag_sym *field,
 				   const char *ev_name,
 				   const char *field_name)
 {
 	define_symbolic_value(ev_name, field_name, field->value, field->str);
 	if (field->next)
 		define_symbolic_values(field->next, ev_name, field_name);
 }

 static void define_symbolic_field(const char *ev_name,
 				  const char *field_name)
 {
 	dSP;

 	ENTER;
 	SAVETMPS;
 	PUSHMARK(SP);

 	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
 	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));

 	PUTBACK;
 	if (get_cv("main::define_symbolic_field", 0))
 		call_pv("main::define_symbolic_field", G_SCALAR);
 	SPAGAIN;
 	PUTBACK;
 	FREETMPS;
 	LEAVE;
 }

 static void define_flag_value(const char *ev_name,
 			      const char *field_name,
 			      const char *field_value,
 			      const char *field_str)
 {
 	unsigned long long value;
 	dSP;

 	value = eval_flag(field_value);

 	ENTER;
 	SAVETMPS;
 	PUSHMARK(SP);

 	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
 	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
 	XPUSHs(sv_2mortal(newSVuv(value)));
 	XPUSHs(sv_2mortal(newSVpv(field_str, 0)));

 	PUTBACK;
 	if (get_cv("main::define_flag_value", 0))
 		call_pv("main::define_flag_value", G_SCALAR);
 	SPAGAIN;
 	PUTBACK;
 	FREETMPS;
 	LEAVE;
 }

 static void define_flag_values(struct print_flag_sym *field,
 			       const char *ev_name,
 			       const char *field_name)
 {
 	define_flag_value(ev_name, field_name, field->value, field->str);
 	if (field->next)
 		define_flag_values(field->next, ev_name, field_name);
 }

 static void define_flag_field(const char *ev_name,
 			      const char *field_name,
 			      const char *delim)
 {
 	dSP;

 	ENTER;
 	SAVETMPS;
 	PUSHMARK(SP);

 	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
 	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
 	XPUSHs(sv_2mortal(newSVpv(delim, 0)));

 	PUTBACK;
 	if (get_cv("main::define_flag_field", 0))
 		call_pv("main::define_flag_field", G_SCALAR);
 	SPAGAIN;
 	PUTBACK;
 	FREETMPS;
 	LEAVE;
 }

 static void define_event_symbols(struct event *event,
 				 const char *ev_name,
 				 struct print_arg *args)
 {
 	switch (args->type) {
 	case PRINT_NULL:
 		break;
 	case PRINT_ATOM:
 		define_flag_value(ev_name, cur_field_name, "0",
 				  args->atom.atom);
 		zero_flag_atom = 0;
 		break;
 	case PRINT_FIELD:
 		if (cur_field_name)
 			free(cur_field_name);
 		cur_field_name = strdup(args->field.name);
 		break;
 	case PRINT_FLAGS:
 		define_event_symbols(event, ev_name, args->flags.field);
 		define_flag_field(ev_name, cur_field_name, args->flags.delim);
 		define_flag_values(args->flags.flags, ev_name, cur_field_name);
 		break;
 	case PRINT_SYMBOL:
 		define_event_symbols(event, ev_name, args->symbol.field);
 		define_symbolic_field(ev_name, cur_field_name);
 		define_symbolic_values(args->symbol.symbols, ev_name,
 				       cur_field_name);
 		break;
 	case PRINT_STRING:
 		break;
 	case PRINT_TYPE:
 		define_event_symbols(event, ev_name, args->typecast.item);
 		break;
 	case PRINT_OP:
 		if (strcmp(args->op.op, ":") == 0)
 			zero_flag_atom = 1;
 		define_event_symbols(event, ev_name, args->op.left);
 		define_event_symbols(event, ev_name, args->op.right);
 		break;
 	default:
 		/* we should warn... */
 		return;
 	}

 	if (args->next)
 		define_event_symbols(event, ev_name, args->next);
 }

 static inline struct event *find_cache_event(int type)
 {
 	static char ev_name[256];
 	struct event *event;

 	if (events[type])
 		return events[type];

 	events[type] = event = trace_find_event(type);
 	if (!event)
 		return NULL;

 	sprintf(ev_name, "%s::%s", event->system, event->name);

 	define_event_symbols(event, ev_name, event->print_fmt.args);

 	return event;
 }

 static void perl_process_event(int cpu, void *data,
 			       int size __unused,
 			       unsigned long long nsecs, char *comm)
 {
 	struct format_field *field;
 	static char handler[256];
 	unsigned long long val;
 	unsigned long s, ns;
 	struct event *event;
 	int type;
 	int pid;

 	dSP;

 	type = trace_parse_common_type(data);

 	event = find_cache_event(type);
 	if (!event)
 		die("ug! no event found for type %d", type);

 	pid = trace_parse_common_pid(data);

 	sprintf(handler, "%s::%s", event->system, event->name);

 	s = nsecs / NSECS_PER_SEC;
 	ns = nsecs - s * NSECS_PER_SEC;

 	scripting_context->event_data = data;

 	ENTER;
 	SAVETMPS;
 	PUSHMARK(SP);

 	XPUSHs(sv_2mortal(newSVpv(handler, 0)));
 	XPUSHs(sv_2mortal(newSViv(PTR2IV(scripting_context))));
 	XPUSHs(sv_2mortal(newSVuv(cpu)));
 	XPUSHs(sv_2mortal(newSVuv(s)));
 	XPUSHs(sv_2mortal(newSVuv(ns)));
 	XPUSHs(sv_2mortal(newSViv(pid)));
 	XPUSHs(sv_2mortal(newSVpv(comm, 0)));

 	/* common fields other than pid can be accessed via xsub fns */

 	for (field = event->format.fields; field; field = field->next) {
 		if (field->flags & FIELD_IS_STRING) {
 			int offset;
 			if (field->flags & FIELD_IS_DYNAMIC) {
 				offset = *(int *)(data + field->offset);
 				offset &= 0xffff;
 			} else
 				offset = field->offset;
 			XPUSHs(sv_2mortal(newSVpv((char *)data + offset, 0)));
 		} else { /* FIELD_IS_NUMERIC */
 			val = read_size(data + field->offset, field->size);
 			if (field->flags & FIELD_IS_SIGNED) {
 				XPUSHs(sv_2mortal(newSViv(val)));
 			} else {
 				XPUSHs(sv_2mortal(newSVuv(val)));
 			}
 		}
 	}

 	PUTBACK;

 	if (get_cv(handler, 0))
 		call_pv(handler, G_SCALAR);
 	else if (get_cv("main::trace_unhandled", 0)) {
 		XPUSHs(sv_2mortal(newSVpv(handler, 0)));
 		XPUSHs(sv_2mortal(newSViv(PTR2IV(scripting_context))));
 		XPUSHs(sv_2mortal(newSVuv(cpu)));
 		XPUSHs(sv_2mortal(newSVuv(nsecs)));
 		XPUSHs(sv_2mortal(newSViv(pid)));
 		XPUSHs(sv_2mortal(newSVpv(comm, 0)));
 		call_pv("main::trace_unhandled", G_SCALAR);
 	}
 	SPAGAIN;
 	PUTBACK;
 	FREETMPS;
 	LEAVE;
 }

 static void run_start_sub(void)
 {
 	dSP; /* access to Perl stack */
 	PUSHMARK(SP);

 	if (get_cv("main::trace_begin", 0))
 		call_pv("main::trace_begin", G_DISCARD | G_NOARGS);
 }

 /*
  * Start trace script
  */
 static int perl_start_script(const char *script, int argc, const char **argv)
 {
 	const char **command_line;
 	int i, err = 0;

 	command_line = malloc((argc + 2) * sizeof(const char *));
 	command_line[0] = "";
 	command_line[1] = script;
 	for (i = 2; i < argc + 2; i++)
 		command_line[i] = argv[i - 2];

 	my_perl = perl_alloc();
 	perl_construct(my_perl);

 	if (perl_parse(my_perl, xs_init, argc + 2, (char **)command_line,
 		       (char **)NULL)) {
 		err = -1;
 		goto error;
 	}

 	if (perl_run(my_perl)) {
 		err = -1;
 		goto error;
 	}

 	if (SvTRUE(ERRSV)) {
 		err = -1;
 		goto error;
 	}

 	run_start_sub();

 	free(command_line);
 	return 0;
 error:
 	perl_free(my_perl);
 	free(command_line);

 	return err;
 }

 /*
  * Stop trace script
  */
 static int perl_stop_script(void)
 {
 	dSP; /* access to Perl stack */
 	PUSHMARK(SP);

 	if (get_cv("main::trace_end", 0))
 		call_pv("main::trace_end", G_DISCARD | G_NOARGS);

 	perl_destruct(my_perl);
 	perl_free(my_perl);

 	return 0;
 }

 static int perl_generate_script(const char *outfile)
 {
 	struct event *event = NULL;
 	struct format_field *f;
 	char fname[PATH_MAX];
 	int not_first, count;
 	FILE *ofp;

 	sprintf(fname, "%s.pl", outfile);
 	ofp = fopen(fname, "w");
 	if (ofp == NULL) {
 		fprintf(stderr, "couldn't open %s\n", fname);
 		return -1;
 	}

 	fprintf(ofp, "# perf trace event handlers, "
 		"generated by perf trace -g perl\n");

 	fprintf(ofp, "# Licensed under the terms of the GNU GPL"
 		" License version 2\n\n");

 	fprintf(ofp, "# The common_* event handler fields are the most useful "
 		"fields common to\n");

 	fprintf(ofp, "# all events.  They don't necessarily correspond to "
 		"the 'common_*' fields\n");

 	fprintf(ofp, "# in the format files.  Those fields not available as "
 		"handler params can\n");

 	fprintf(ofp, "# be retrieved using Perl functions of the form "
 		"common_*($context).\n");

 	fprintf(ofp, "# See Context.pm for the list of available "
 		"functions.\n\n");

 	fprintf(ofp, "use lib \"$ENV{'PERF_EXEC_PATH'}/scripts/perl/"
 		"Perf-Trace-Util/lib\";\n");

 	fprintf(ofp, "use lib \"./Perf-Trace-Util/lib\";\n");
 	fprintf(ofp, "use Perf::Trace::Core;\n");
 	fprintf(ofp, "use Perf::Trace::Context;\n");
 	fprintf(ofp, "use Perf::Trace::Util;\n\n");

 	fprintf(ofp, "sub trace_begin\n{\n\t# optional\n}\n\n");
 	fprintf(ofp, "sub trace_end\n{\n\t# optional\n}\n\n");

 	while ((event = trace_find_next_event(event))) {
 		fprintf(ofp, "sub %s::%s\n{\n", event->system, event->name);
 		fprintf(ofp, "\tmy (");

 		fprintf(ofp, "$event_name, ");
 		fprintf(ofp, "$context, ");
 		fprintf(ofp, "$common_cpu, ");
 		fprintf(ofp, "$common_secs, ");
 		fprintf(ofp, "$common_nsecs,\n");
 		fprintf(ofp, "\t    $common_pid, ");
 		fprintf(ofp, "$common_comm,\n\t    ");

 		not_first = 0;
 		count = 0;

 		for (f = event->format.fields; f; f = f->next) {
 			if (not_first++)
 				fprintf(ofp, ", ");
 			if (++count % 5 == 0)
 				fprintf(ofp, "\n\t    ");

 			fprintf(ofp, "$%s", f->name);
 		}
 		fprintf(ofp, ") = @_;\n\n");

 		fprintf(ofp, "\tprint_header($event_name, $common_cpu, "
 			"$common_secs, $common_nsecs,\n\t             "
 			"$common_pid, $common_comm);\n\n");

 		fprintf(ofp, "\tprintf(\"");

 		not_first = 0;
 		count = 0;

 		for (f = event->format.fields; f; f = f->next) {
 			if (not_first++)
 				fprintf(ofp, ", ");
 			if (count && count % 4 == 0) {
 				fprintf(ofp, "\".\n\t       \"");
 			}
 			count++;

 			fprintf(ofp, "%s=", f->name);
 			if (f->flags & FIELD_IS_STRING ||
 			    f->flags & FIELD_IS_FLAG ||
 			    f->flags & FIELD_IS_SYMBOLIC)
 				fprintf(ofp, "%%s");
 			else if (f->flags & FIELD_IS_SIGNED)
 				fprintf(ofp, "%%d");
 			else
 				fprintf(ofp, "%%u");
 		}

 		fprintf(ofp, "\\n\",\n\t       ");

 		not_first = 0;
 		count = 0;

 		for (f = event->format.fields; f; f = f->next) {
 			if (not_first++)
 				fprintf(ofp, ", ");

 			if (++count % 5 == 0)
 				fprintf(ofp, "\n\t       ");

 			if (f->flags & FIELD_IS_FLAG) {
 				if ((count - 1) % 5 != 0) {
 					fprintf(ofp, "\n\t       ");
 					count = 4;
 				}
 				fprintf(ofp, "flag_str(\"");
 				fprintf(ofp, "%s::%s\", ", event->system,
 					event->name);
 				fprintf(ofp, "\"%s\", $%s)", f->name,
 					f->name);
 			} else if (f->flags & FIELD_IS_SYMBOLIC) {
 				if ((count - 1) % 5 != 0) {
 					fprintf(ofp, "\n\t       ");
 					count = 4;
 				}
 				fprintf(ofp, "symbol_str(\"");
 				fprintf(ofp, "%s::%s\", ", event->system,
 					event->name);
 				fprintf(ofp, "\"%s\", $%s)", f->name,
 					f->name);
 			} else
 				fprintf(ofp, "$%s", f->name);
 		}

 		fprintf(ofp, ");\n");
 		fprintf(ofp, "}\n\n");
 	}

 	fprintf(ofp, "sub trace_unhandled\n{\n\tmy ($event_name, $context, "
 		"$common_cpu, $common_secs, $common_nsecs,\n\t    "
 		"$common_pid, $common_comm) = @_;\n\n");

 	fprintf(ofp, "\tprint_header($event_name, $common_cpu, "
 		"$common_secs, $common_nsecs,\n\t             $common_pid, "
 		"$common_comm);\n}\n\n");

 	fprintf(ofp, "sub print_header\n{\n"
 		"\tmy ($event_name, $cpu, $secs, $nsecs, $pid, $comm) = @_;\n\n"
 		"\tprintf(\"%%-20s %%5u %%05u.%%09u %%8u %%-20s \",\n\t       "
 		"$event_name, $cpu, $secs, $nsecs, $pid, $comm);\n}");

 	fclose(ofp);

 	fprintf(stderr, "generated Perl script: %s\n", fname);

 	return 0;
 }

 struct scripting_ops perl_scripting_ops = {
 	.name = "Perl",
 	.start_script = perl_start_script,
 	.stop_script = perl_stop_script,
 	.process_event = perl_process_event,
 	.generate_script = perl_generate_script,
 };
	/*
	* trace-event-perl. Feed perf trace events to an embedded Perl interpreter.
	*
	* Copyright (C) 2009 Tom Zanussi <tzanussi@gmail.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*
	*/

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <ctype.h>
	#include <errno.h>

	#include "../../perf.h"
	#include "../util.h"
	#include "../trace-event.h"

	#include <EXTERN.h>
	#include <perl.h>

	void boot_Perf__Trace__Context(pTHX_ CV *cv);
	void boot_DynaLoader(pTHX_ CV *cv);
	typedef PerlInterpreter * INTERP;

	void xs_init(pTHX);

	void xs_init(pTHX)
	{
	const char *file = __FILE__;
	dXSUB_SYS;

	newXS("Perf::Trace::Context::bootstrap", boot_Perf__Trace__Context,
	file);
	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
	}

	INTERP my_perl;

	#define FTRACE_MAX_EVENT \
	((1 << (sizeof(unsigned short) * 8)) - 1)

	struct event *events[FTRACE_MAX_EVENT];

	extern struct scripting_context *scripting_context;

	static char *cur_field_name;
	static int zero_flag_atom;

	static void define_symbolic_value(const char *ev_name,
	const char *field_name,
	const char *field_value,
	const char *field_str)
	{
	unsigned long long value;
	dSP;

	value = eval_flag(field_value);

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
	XPUSHs(sv_2mortal(newSVuv(value)));
	XPUSHs(sv_2mortal(newSVpv(field_str, 0)));

	PUTBACK;
	if (get_cv("main::define_symbolic_value", 0))
	call_pv("main::define_symbolic_value", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
	}

	static void define_symbolic_values(struct print_flag_sym *field,
	const char *ev_name,
	const char *field_name)
	{
	define_symbolic_value(ev_name, field_name, field->value, field->str);
	if (field->next)
	define_symbolic_values(field->next, ev_name, field_name);
	}

	static void define_symbolic_field(const char *ev_name,
	const char *field_name)
	{
	dSP;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));

	PUTBACK;
	if (get_cv("main::define_symbolic_field", 0))
	call_pv("main::define_symbolic_field", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
	}

	static void define_flag_value(const char *ev_name,
	const char *field_name,
	const char *field_value,
	const char *field_str)
	{
	unsigned long long value;
	dSP;

	value = eval_flag(field_value);

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
	XPUSHs(sv_2mortal(newSVuv(value)));
	XPUSHs(sv_2mortal(newSVpv(field_str, 0)));

	PUTBACK;
	if (get_cv("main::define_flag_value", 0))
	call_pv("main::define_flag_value", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
	}

	static void define_flag_values(struct print_flag_sym *field,
	const char *ev_name,
	const char *field_name)
	{
	define_flag_value(ev_name, field_name, field->value, field->str);
	if (field->next)
	define_flag_values(field->next, ev_name, field_name);
	}

	static void define_flag_field(const char *ev_name,
	const char *field_name,
	const char *delim)
	{
	dSP;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(ev_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(field_name, 0)));
	XPUSHs(sv_2mortal(newSVpv(delim, 0)));

	PUTBACK;
	if (get_cv("main::define_flag_field", 0))
	call_pv("main::define_flag_field", G_SCALAR);
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
	}

	static void define_event_symbols(struct event *event,
	const char *ev_name,
	struct print_arg *args)
	{
	switch (args->type) {
	case PRINT_NULL:
	break;
	case PRINT_ATOM:
	define_flag_value(ev_name, cur_field_name, "0",
	args->atom.atom);
	zero_flag_atom = 0;
	break;
	case PRINT_FIELD:
	if (cur_field_name)
	free(cur_field_name);
	cur_field_name = strdup(args->field.name);
	break;
	case PRINT_FLAGS:
	define_event_symbols(event, ev_name, args->flags.field);
	define_flag_field(ev_name, cur_field_name, args->flags.delim);
	define_flag_values(args->flags.flags, ev_name, cur_field_name);
	break;
	case PRINT_SYMBOL:
	define_event_symbols(event, ev_name, args->symbol.field);
	define_symbolic_field(ev_name, cur_field_name);
	define_symbolic_values(args->symbol.symbols, ev_name,
	cur_field_name);
	break;
	case PRINT_STRING:
	break;
	case PRINT_TYPE:
	define_event_symbols(event, ev_name, args->typecast.item);
	break;
	case PRINT_OP:
	if (strcmp(args->op.op, ":") == 0)
	zero_flag_atom = 1;
	define_event_symbols(event, ev_name, args->op.left);
	define_event_symbols(event, ev_name, args->op.right);
	break;
	default:
	/* we should warn... */
	return;
	}

	if (args->next)
	define_event_symbols(event, ev_name, args->next);
	}

	static inline struct event *find_cache_event(int type)
	{
	static char ev_name[256];
	struct event *event;

	if (events[type])
	return events[type];

	events[type] = event = trace_find_event(type);
	if (!event)
	return NULL;

	sprintf(ev_name, "%s::%s", event->system, event->name);

	define_event_symbols(event, ev_name, event->print_fmt.args);

	return event;
	}

	static void perl_process_event(int cpu, void *data,
	int size __unused,
	unsigned long long nsecs, char *comm)
	{
	struct format_field *field;
	static char handler[256];
	unsigned long long val;
	unsigned long s, ns;
	struct event *event;
	int type;
	int pid;

	dSP;

	type = trace_parse_common_type(data);

	event = find_cache_event(type);
	if (!event)
	die("ug! no event found for type %d", type);

	pid = trace_parse_common_pid(data);

	sprintf(handler, "%s::%s", event->system, event->name);

	s = nsecs / NSECS_PER_SEC;
	ns = nsecs - s * NSECS_PER_SEC;

	scripting_context->event_data = data;

	ENTER;
	SAVETMPS;
	PUSHMARK(SP);

	XPUSHs(sv_2mortal(newSVpv(handler, 0)));
	XPUSHs(sv_2mortal(newSViv(PTR2IV(scripting_context))));
	XPUSHs(sv_2mortal(newSVuv(cpu)));
	XPUSHs(sv_2mortal(newSVuv(s)));
	XPUSHs(sv_2mortal(newSVuv(ns)));
	XPUSHs(sv_2mortal(newSViv(pid)));
	XPUSHs(sv_2mortal(newSVpv(comm, 0)));

	/* common fields other than pid can be accessed via xsub fns */

	for (field = event->format.fields; field; field = field->next) {
	if (field->flags & FIELD_IS_STRING) {
	int offset;
	if (field->flags & FIELD_IS_DYNAMIC) {
	offset = (int )(data + field->offset);
	offset &= 0xffff;
	} else
	offset = field->offset;
	XPUSHs(sv_2mortal(newSVpv((char *)data + offset, 0)));
	} else { /* FIELD_IS_NUMERIC */
	val = read_size(data + field->offset, field->size);
	if (field->flags & FIELD_IS_SIGNED) {
	XPUSHs(sv_2mortal(newSViv(val)));
	} else {
	XPUSHs(sv_2mortal(newSVuv(val)));
	}
	}
	}

	PUTBACK;

	if (get_cv(handler, 0))
	call_pv(handler, G_SCALAR);
	else if (get_cv("main::trace_unhandled", 0)) {
	XPUSHs(sv_2mortal(newSVpv(handler, 0)));
	XPUSHs(sv_2mortal(newSViv(PTR2IV(scripting_context))));
	XPUSHs(sv_2mortal(newSVuv(cpu)));
	XPUSHs(sv_2mortal(newSVuv(nsecs)));
	XPUSHs(sv_2mortal(newSViv(pid)));
	XPUSHs(sv_2mortal(newSVpv(comm, 0)));
	call_pv("main::trace_unhandled", G_SCALAR);
	}
	SPAGAIN;
	PUTBACK;
	FREETMPS;
	LEAVE;
	}

	static void run_start_sub(void)
	{
	dSP; /* access to Perl stack */
	PUSHMARK(SP);

	if (get_cv("main::trace_begin", 0))
	call_pv("main::trace_begin", G_DISCARD \| G_NOARGS);
	}

	/*
	* Start trace script
	*/
	static int perl_start_script(const char script, int argc, const char *argv)
	{
	const char **command_line;
	int i, err = 0;

	command_line = malloc((argc + 2) * sizeof(const char *));
	command_line[0] = "";
	command_line[1] = script;
	for (i = 2; i < argc + 2; i++)
	command_line[i] = argv[i - 2];

	my_perl = perl_alloc();
	perl_construct(my_perl);

	if (perl_parse(my_perl, xs_init, argc + 2, (char **)command_line,
	(char **)NULL)) {
	err = -1;
	goto error;
	}

	if (perl_run(my_perl)) {
	err = -1;
	goto error;
	}

	if (SvTRUE(ERRSV)) {
	err = -1;
	goto error;
	}

	run_start_sub();

	free(command_line);
	return 0;
	error:
	perl_free(my_perl);
	free(command_line);

	return err;
	}

	/*
	* Stop trace script
	*/
	static int perl_stop_script(void)
	{
	dSP; /* access to Perl stack */
	PUSHMARK(SP);

	if (get_cv("main::trace_end", 0))
	call_pv("main::trace_end", G_DISCARD \| G_NOARGS);

	perl_destruct(my_perl);
	perl_free(my_perl);

	return 0;
	}

	static int perl_generate_script(const char *outfile)
	{
	struct event *event = NULL;
	struct format_field *f;
	char fname[PATH_MAX];
	int not_first, count;
	FILE *ofp;

	sprintf(fname, "%s.pl", outfile);
	ofp = fopen(fname, "w");
	if (ofp == NULL) {
	fprintf(stderr, "couldn't open %s\n", fname);
	return -1;
	}

	fprintf(ofp, "# perf trace event handlers, "
	"generated by perf trace -g perl\n");

	fprintf(ofp, "# Licensed under the terms of the GNU GPL"
	" License version 2\n\n");

	fprintf(ofp, "# The common_* event handler fields are the most useful "
	"fields common to\n");

	fprintf(ofp, "# all events. They don't necessarily correspond to "
	"the 'common_*' fields\n");

	fprintf(ofp, "# in the format files. Those fields not available as "
	"handler params can\n");

	fprintf(ofp, "# be retrieved using Perl functions of the form "
	"common_*($context).\n");

	fprintf(ofp, "# See Context.pm for the list of available "
	"functions.\n\n");

	fprintf(ofp, "use lib \"$ENV{'PERF_EXEC_PATH'}/scripts/perl/"
	"Perf-Trace-Util/lib\";\n");

	fprintf(ofp, "use lib \"./Perf-Trace-Util/lib\";\n");
	fprintf(ofp, "use Perf::Trace::Core;\n");
	fprintf(ofp, "use Perf::Trace::Context;\n");
	fprintf(ofp, "use Perf::Trace::Util;\n\n");

	fprintf(ofp, "sub trace_begin\n{\n\t# optional\n}\n\n");
	fprintf(ofp, "sub trace_end\n{\n\t# optional\n}\n\n");

	while ((event = trace_find_next_event(event))) {
	fprintf(ofp, "sub %s::%s\n{\n", event->system, event->name);
	fprintf(ofp, "\tmy (");

	fprintf(ofp, "$event_name, ");
	fprintf(ofp, "$context, ");
	fprintf(ofp, "$common_cpu, ");
	fprintf(ofp, "$common_secs, ");
	fprintf(ofp, "$common_nsecs,\n");
	fprintf(ofp, "\t $common_pid, ");
	fprintf(ofp, "$common_comm,\n\t ");

	not_first = 0;
	count = 0;

	for (f = event->format.fields; f; f = f->next) {
	if (not_first++)
	fprintf(ofp, ", ");
	if (++count % 5 == 0)
	fprintf(ofp, "\n\t ");

	fprintf(ofp, "$%s", f->name);
	}
	fprintf(ofp, ") = @_;\n\n");

	fprintf(ofp, "\tprint_header($event_name, $common_cpu, "
	"$common_secs, $common_nsecs,\n\t "
	"$common_pid, $common_comm);\n\n");

	fprintf(ofp, "\tprintf(\"");

	not_first = 0;
	count = 0;

	for (f = event->format.fields; f; f = f->next) {
	if (not_first++)
	fprintf(ofp, ", ");
	if (count && count % 4 == 0) {
	fprintf(ofp, "\".\n\t \"");
	}
	count++;

	fprintf(ofp, "%s=", f->name);
	if (f->flags & FIELD_IS_STRING \|\|
	f->flags & FIELD_IS_FLAG \|\|
	f->flags & FIELD_IS_SYMBOLIC)
	fprintf(ofp, "%%s");
	else if (f->flags & FIELD_IS_SIGNED)
	fprintf(ofp, "%%d");
	else
	fprintf(ofp, "%%u");
	}

	fprintf(ofp, "\\n\",\n\t ");

	not_first = 0;
	count = 0;

	for (f = event->format.fields; f; f = f->next) {
	if (not_first++)
	fprintf(ofp, ", ");

	if (++count % 5 == 0)
	fprintf(ofp, "\n\t ");

	if (f->flags & FIELD_IS_FLAG) {
	if ((count - 1) % 5 != 0) {
	fprintf(ofp, "\n\t ");
	count = 4;
	}
	fprintf(ofp, "flag_str(\"");
	fprintf(ofp, "%s::%s\", ", event->system,
	event->name);
	fprintf(ofp, "\"%s\", $%s)", f->name,
	f->name);
	} else if (f->flags & FIELD_IS_SYMBOLIC) {
	if ((count - 1) % 5 != 0) {
	fprintf(ofp, "\n\t ");
	count = 4;
	}
	fprintf(ofp, "symbol_str(\"");
	fprintf(ofp, "%s::%s\", ", event->system,
	event->name);
	fprintf(ofp, "\"%s\", $%s)", f->name,
	f->name);
	} else
	fprintf(ofp, "$%s", f->name);
	}

	fprintf(ofp, ");\n");
	fprintf(ofp, "}\n\n");
	}

	fprintf(ofp, "sub trace_unhandled\n{\n\tmy ($event_name, $context, "
	"$common_cpu, $common_secs, $common_nsecs,\n\t "
	"$common_pid, $common_comm) = @_;\n\n");

	fprintf(ofp, "\tprint_header($event_name, $common_cpu, "
	"$common_secs, $common_nsecs,\n\t $common_pid, "
	"$common_comm);\n}\n\n");

	fprintf(ofp, "sub print_header\n{\n"
	"\tmy ($event_name, $cpu, $secs, $nsecs, $pid, $comm) = @_;\n\n"
	"\tprintf(\"%%-20s %%5u %%05u.%%09u %%8u %%-20s \",\n\t "
	"$event_name, $cpu, $secs, $nsecs, $pid, $comm);\n}");

	fclose(ofp);

	fprintf(stderr, "generated Perl script: %s\n", fname);

	return 0;
	}

	struct scripting_ops perl_scripting_ops = {
	.name = "Perl",
	.start_script = perl_start_script,
	.stop_script = perl_stop_script,
	.process_event = perl_process_event,
	.generate_script = perl_generate_script,
	};