diff mbox

[RFC,v3,1/8] tracetool: Rewrite infrastructure as python modules

Message ID 20120327194918.7241.10931.stgit@ginnungagap.bsc.es
State New
Headers show

Commit Message

Lluís Vilanova March 27, 2012, 7:49 p.m. UTC
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
 Makefile.objs                         |    6 
 Makefile.target                       |   13 -
 configure                             |    4 
 scripts/tracetool                     |  648 ---------------------------------
 scripts/tracetool.py                  |  110 ++++++
 scripts/tracetool/__init__.py         |  215 +++++++++++
 scripts/tracetool/backend/__init__.py |  119 ++++++
 scripts/tracetool/format/__init__.py  |   96 +++++
 8 files changed, 552 insertions(+), 659 deletions(-)
 delete mode 100755 scripts/tracetool
 create mode 100755 scripts/tracetool.py
 create mode 100644 scripts/tracetool/__init__.py
 create mode 100644 scripts/tracetool/backend/__init__.py
 create mode 100644 scripts/tracetool/format/__init__.py

Comments

Stefan Hajnoczi March 30, 2012, 7:27 a.m. UTC | #1
On Tue, Mar 27, 2012 at 09:49:18PM +0200, Lluís Vilanova wrote:
> diff --git a/scripts/tracetool.py b/scripts/tracetool.py
> new file mode 100755
> index 0000000..70bf79a
> --- /dev/null
> +++ b/scripts/tracetool.py
> @@ -0,0 +1,110 @@
> +#!/usr/bin/env python
> +# -*- coding: utf-8 -*-
> +
> +"""
> +Command-line wrapper for the tracetool machinery.
> +"""
> +
> +__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
> +__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
> +__license__    = "GPL version 2 or (at your option) any later version"
> +
> +__maintainer__ = "Stefan Hajnoczi"
> +__email__      = "stefanha@linux.vnet.ibm.com"
> +
> +
> +import sys
> +import getopt
> +
> +from tracetool import error_write, out
> +import tracetool.backend
> +import tracetool.format
> +
> +
> +_SCRIPT = ""
> +
> +def error_opt(msg = None):
> +    if msg is not None:
> +        error_write("Error: " + msg + "\n")
> +
> +    backend_descr = "\n".join([ "    %-15s %s" % (n, d)
> +                                for n,d in tracetool.backend.get_list() ])
> +    format_descr = "\n".join([ "    %-15s %s" % (n, d)
> +                               for n,d in tracetool.format.get_list() ])
> +    error_write("""\
> +Usage: %(script)s --format=<format> --backend=<backend> [<options>]
> +
> +Backends:
> +%(backends)s
> +
> +Formats:
> +%(formats)s
> +
> +Options:
> +    --help                   This help message.
> +    --list-backends          Print list of available backends.
> +    --check-backend          Check if the given backend is valid.
> +""" % {
> +            "script" : _SCRIPT,
> +            "backends" : backend_descr,
> +            "formats" : format_descr,
> +            })
> +
> +    if msg is None:
> +        sys.exit(0)
> +    else:
> +        sys.exit(1)
> +
> +
> +def main(args):
> +    global _SCRIPT
> +    _SCRIPT = args[0]
> +
> +    long_opts  = [ "backend=", "format=", "help", "list-backends", "check-backend" ]
> +    long_opts += [ "binary=", "target-type=", "target-arch=", "probe-prefix=" ]
> +
> +    try:
> +        opts, args = getopt.getopt(args[1:], "", long_opts)
> +    except getopt.GetoptError as err:
> +        error_opt(str(err))
> +
> +    check_backend = False
> +    arg_backend = ""
> +    arg_format = ""
> +    for opt, arg in opts:
> +        if opt == "--help":
> +            error_opt()
> +
> +        elif opt == "--backend":
> +            arg_backend = arg
> +        elif opt == "--format":
> +            arg_format = arg
> +
> +        elif opt == "--list-backends":
> +            public_backends = tracetool.backend.get_list(only_public = True)
> +            out(", ".join([ b for b,_ in public_backends ]))
> +            sys.exit(0)
> +        elif opt == "--check-backend":
> +            check_backend = True
> +
> +        else:
> +            error_opt("unhandled option: %s" % opt)
> +
> +    if arg_backend is None:
> +        error_opt("backend not set")
> +
> +    if check_backend:
> +        if tracetool.backend.exists(arg_backend):
> +            sys.exit(0)
> +        else:
> +            sys.exit(1)
> +
> +    kwargs = {}
> +
> +    try:
> +        tracetool.generate(sys.stdin, arg_format, arg_backend, **kwargs)

If forgot to ask what kwargs is doing here?   Can we default to {}?
Otherwise let's drop it for now since there are no options defined yet.

Stefan
Lluís Vilanova March 30, 2012, 4:55 p.m. UTC | #2
Stefan Hajnoczi writes:
>> +    kwargs = {}
>> +
>> +    try:
>> +        tracetool.generate(sys.stdin, arg_format, arg_backend, **kwargs)

> If forgot to ask what kwargs is doing here?   Can we default to {}?
> Otherwise let's drop it for now since there are no options defined yet.

It's used later in the patch adding dtrace support. I just thought it would be
better to maintain the interface of 'tracetool.generate' instead of adding new
parameters later when necessary.


Lluis
Stefan Hajnoczi April 2, 2012, 7:36 a.m. UTC | #3
On Fri, Mar 30, 2012 at 06:55:16PM +0200, Lluís Vilanova wrote:
> Stefan Hajnoczi writes:
> >> +    kwargs = {}
> >> +
> >> +    try:
> >> +        tracetool.generate(sys.stdin, arg_format, arg_backend, **kwargs)
> 
> > If forgot to ask what kwargs is doing here?   Can we default to {}?
> > Otherwise let's drop it for now since there are no options defined yet.
> 
> It's used later in the patch adding dtrace support. I just thought it would be
> better to maintain the interface of 'tracetool.generate' instead of adding new
> parameters later when necessary.

Thanks for pointing that out.  I went back to look at how the
dtrace-specific options get passed in.  I noticed you assigned them
directly to dtrace.py module variables - probably because you didn't
want to add the (mostly unused) kwargs argument to all code generation
functions?

For now I think this is okay since most backends don't care about
kwargs.  If we need it more maybe we should think of a cleaner solution.

Stefan
Lluís Vilanova April 2, 2012, 12:57 p.m. UTC | #4
Stefan Hajnoczi writes:

> On Fri, Mar 30, 2012 at 06:55:16PM +0200, Lluís Vilanova wrote:
>> Stefan Hajnoczi writes:
>> >> +    kwargs = {}
>> >> +
>> >> +    try:
>> >> +        tracetool.generate(sys.stdin, arg_format, arg_backend, **kwargs)
>> 
>> > If forgot to ask what kwargs is doing here?   Can we default to {}?
>> > Otherwise let's drop it for now since there are no options defined yet.
>> 
>> It's used later in the patch adding dtrace support. I just thought it would be
>> better to maintain the interface of 'tracetool.generate' instead of adding new
>> parameters later when necessary.

> Thanks for pointing that out.  I went back to look at how the
> dtrace-specific options get passed in.  I noticed you assigned them
> directly to dtrace.py module variables - probably because you didn't
> want to add the (mostly unused) kwargs argument to all code generation
> functions?

> For now I think this is okay since most backends don't care about
> kwargs.  If we need it more maybe we should think of a cleaner solution.

Exactly. Using the kwargs approach all over the place would do the job, but
right now there are only two of these arguments, which looks manageable using
explicit arguments (since v4).


Lluis
diff mbox

Patch

diff --git a/Makefile.objs b/Makefile.objs
index 226b01d..8e56f48 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -373,12 +373,12 @@  else
 trace.h: trace.h-timestamp
 endif
 trace.h-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
-	$(call quiet-command,sh $(SRC_PATH)/scripts/tracetool --$(TRACE_BACKEND) -h < $< > $@,"  GEN   trace.h")
+	$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/tracetool.py --format=h --backend=$(TRACE_BACKEND) < $< > $@,"  GEN   trace.h")
 	@cmp -s $@ trace.h || cp $@ trace.h
 
 trace.c: trace.c-timestamp
 trace.c-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
-	$(call quiet-command,sh $(SRC_PATH)/scripts/tracetool --$(TRACE_BACKEND) -c < $< > $@,"  GEN   trace.c")
+	$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/tracetool.py --format=c --backend=$(TRACE_BACKEND) < $< > $@,"  GEN   trace.c")
 	@cmp -s $@ trace.c || cp $@ trace.c
 
 trace.o: trace.c $(GENERATED_HEADERS)
@@ -391,7 +391,7 @@  trace-dtrace.h: trace-dtrace.dtrace
 # rule file. So we use '.dtrace' instead
 trace-dtrace.dtrace: trace-dtrace.dtrace-timestamp
 trace-dtrace.dtrace-timestamp: $(SRC_PATH)/trace-events $(BUILD_DIR)/config-host.mak
-	$(call quiet-command,sh $(SRC_PATH)/scripts/tracetool --$(TRACE_BACKEND) -d < $< > $@,"  GEN   trace-dtrace.dtrace")
+	$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/tracetool.py --format=d --backend=$(TRACE_BACKEND) < $< > $@,"  GEN   trace-dtrace.dtrace")
 	@cmp -s $@ trace-dtrace.dtrace || cp $@ trace-dtrace.dtrace
 
 trace-dtrace.o: trace-dtrace.dtrace $(GENERATED_HEADERS)
diff --git a/Makefile.target b/Makefile.target
index 63cf769..fe28e8b 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -59,12 +59,13 @@  TARGET_TYPE=system
 endif
 
 $(QEMU_PROG).stp:
-	$(call quiet-command,sh $(SRC_PATH)/scripts/tracetool \
-		--$(TRACE_BACKEND) \
-		--binary $(bindir)/$(QEMU_PROG) \
-		--target-arch $(TARGET_ARCH) \
-		--target-type $(TARGET_TYPE) \
-		--stap < $(SRC_PATH)/trace-events > $(QEMU_PROG).stp,"  GEN   $(QEMU_PROG).stp")
+	$(call quiet-command,$(PYTHON) $(SRC_PATH)/scripts/tracetool.py \
+		--format=stap \
+		--backend=$(TRACE_BACKEND) \
+		--binary=$(bindir)/$(QEMU_PROG) \
+		--target-arch=$(TARGET_ARCH) \
+		--target-type=$(TARGET_TYPE) \
+		< $(SRC_PATH)/trace-events > $(QEMU_PROG).stp,"  GEN   $(QEMU_PROG).stp")
 else
 stap:
 endif
diff --git a/configure b/configure
index 8b4e3c1..c2d6117 100755
--- a/configure
+++ b/configure
@@ -1097,7 +1097,7 @@  echo "  --disable-docs           disable documentation build"
 echo "  --disable-vhost-net      disable vhost-net acceleration support"
 echo "  --enable-vhost-net       enable vhost-net acceleration support"
 echo "  --enable-trace-backend=B Set trace backend"
-echo "                           Available backends:" $("$source_path"/scripts/tracetool --list-backends)
+echo "                           Available backends:" $($python "$source_path"/scripts/tracetool.py --list-backends)
 echo "  --with-trace-file=NAME   Full PATH,NAME of file to store traces"
 echo "                           Default:trace-<pid>"
 echo "  --disable-spice          disable spice"
@@ -2654,7 +2654,7 @@  fi
 ##########################################
 # check if trace backend exists
 
-sh "$source_path/scripts/tracetool" "--$trace_backend" --check-backend > /dev/null 2> /dev/null
+$python "$source_path/scripts/tracetool.py" "--backend=$trace_backend" --check-backend  > /dev/null 2> /dev/null
 if test "$?" -ne 0 ; then
   echo
   echo "Error: invalid trace backend"
diff --git a/scripts/tracetool b/scripts/tracetool
deleted file mode 100755
index 65bd0a1..0000000
--- a/scripts/tracetool
+++ /dev/null
@@ -1,648 +0,0 @@ 
-#!/bin/sh
-#
-# Code generator for trace events
-#
-# Copyright IBM, Corp. 2010
-#
-# This work is licensed under the terms of the GNU GPL, version 2.  See
-# the COPYING file in the top-level directory.
-
-# Disable pathname expansion, makes processing text with '*' characters simpler
-set -f
-
-usage()
-{
-    cat >&2 <<EOF
-usage: $0 [--nop | --simple | --stderr | --ust | --dtrace] [-h | -c]
-Generate tracing code for a file on stdin.
-
-Backends:
-  --nop     Tracing disabled
-  --simple  Simple built-in backend
-  --stderr  Stderr built-in backend
-  --ust     LTTng User Space Tracing backend
-  --dtrace  DTrace/SystemTAP backend
-
-Output formats:
-  -h     Generate .h file
-  -c     Generate .c file
-  -d     Generate .d file (DTrace only)
-  --stap Generate .stp file (DTrace with SystemTAP only)
-
-Options:
-  --binary       [path]    Full path to QEMU binary
-  --target-arch  [arch]    QEMU emulator target arch
-  --target-type  [type]    QEMU emulator target type ('system' or 'user')
-  --probe-prefix [prefix]  Prefix for dtrace probe names
-                           (default: qemu-\$targettype-\$targetarch)
-
-EOF
-    exit 1
-}
-
-# Print a line without interpreting backslash escapes
-#
-# The built-in echo command may interpret backslash escapes without an option
-# to disable this behavior.
-puts()
-{
-    printf "%s\n" "$1"
-}
-
-# Get the name of a trace event
-get_name()
-{
-    local name
-    name=${1%%\(*}
-    echo "${name##* }"
-}
-
-# Get the given property of a trace event
-# 1: trace-events line
-# 2: property name
-# -> return 0 if property is present, or 1 otherwise
-has_property()
-{
-    local props prop
-    props=${1%%\(*}
-    props=${props% *}
-    for prop in $props; do
-        if [ "$prop" = "$2" ]; then
-            return 0
-        fi
-    done
-    return 1
-}
-
-# Get the argument list of a trace event, including types and names
-get_args()
-{
-    local args
-    args=${1#*\(}
-    args=${args%%\)*}
-    echo "$args"
-}
-
-# Get the argument name list of a trace event
-get_argnames()
-{
-    local nfields field name sep
-    nfields=0
-    sep="$2"
-    for field in $(get_args "$1"); do
-        nfields=$((nfields + 1))
-
-        # Drop pointer star
-        field=${field#\*}
-
-        # Only argument names have commas at the end
-        name=${field%,}
-        test "$field" = "$name" && continue
-
-        printf "%s%s " $name $sep
-    done
-
-    # Last argument name
-    if [ "$nfields" -gt 1 ]
-    then
-        printf "%s" "$name"
-    fi
-}
-
-# Get the number of arguments to a trace event
-get_argc()
-{
-    local name argc
-    argc=0
-    for name in $(get_argnames "$1", ","); do
-        argc=$((argc + 1))
-    done
-    echo $argc
-}
-
-# Get the format string including double quotes for a trace event
-get_fmt()
-{
-    puts "${1#*)}"
-}
-
-linetoh_begin_nop()
-{
-    return
-}
-
-linetoh_nop()
-{
-    local name args
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-
-    # Define an empty function for the trace event
-    cat <<EOF
-static inline void trace_$name($args)
-{
-}
-EOF
-}
-
-linetoh_end_nop()
-{
-    return
-}
-
-linetoc_begin_nop()
-{
-    return
-}
-
-linetoc_nop()
-{
-    # No need for function definitions in nop backend
-    return
-}
-
-linetoc_end_nop()
-{
-    return
-}
-
-linetoh_begin_simple()
-{
-    cat <<EOF
-#include "trace/simple.h"
-EOF
-
-    simple_event_num=0
-}
-
-cast_args_to_uint64_t()
-{
-    local arg
-    for arg in $(get_argnames "$1", ","); do
-        printf "%s" "(uint64_t)(uintptr_t)$arg"
-    done
-}
-
-linetoh_simple()
-{
-    local name args argc trace_args
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-    argc=$(get_argc "$1")
-
-    trace_args="$simple_event_num"
-    if [ "$argc" -gt 0 ]
-    then
-        trace_args="$trace_args, $(cast_args_to_uint64_t "$1")"
-    fi
-
-    cat <<EOF
-static inline void trace_$name($args)
-{
-    trace$argc($trace_args);
-}
-EOF
-
-    simple_event_num=$((simple_event_num + 1))
-}
-
-linetoh_end_simple()
-{
-    cat <<EOF
-#define NR_TRACE_EVENTS $simple_event_num
-extern TraceEvent trace_list[NR_TRACE_EVENTS];
-EOF
-}
-
-linetoc_begin_simple()
-{
-    cat <<EOF
-#include "trace.h"
-
-TraceEvent trace_list[] = {
-EOF
-    simple_event_num=0
-
-}
-
-linetoc_simple()
-{
-    local name
-    name=$(get_name "$1")
-    cat <<EOF
-{.tp_name = "$name", .state=0},
-EOF
-    simple_event_num=$((simple_event_num + 1))
-}
-
-linetoc_end_simple()
-{
-    cat <<EOF
-};
-EOF
-}
-
-#STDERR
-linetoh_begin_stderr()
-{
-    cat <<EOF
-#include <stdio.h>
-#include "trace/stderr.h"
-
-extern TraceEvent trace_list[];
-EOF
-
-    stderr_event_num=0
-}
-
-linetoh_stderr()
-{
-    local name args argnames argc fmt
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-    argnames=$(get_argnames "$1" ",")
-    argc=$(get_argc "$1")
-    fmt=$(get_fmt "$1")
-
-    if [ "$argc" -gt 0 ]; then
-        argnames=", $argnames"
-    fi
-
-    cat <<EOF
-static inline void trace_$name($args)
-{
-    if (trace_list[$stderr_event_num].state != 0) {
-        fprintf(stderr, "$name " $fmt "\n" $argnames);
-    }
-}
-EOF
-    stderr_event_num=$((stderr_event_num + 1))
-
-}
-
-linetoh_end_stderr()
-{
-    cat <<EOF
-#define NR_TRACE_EVENTS $stderr_event_num
-EOF
-}
-
-linetoc_begin_stderr()
-{
-    cat <<EOF
-#include "trace.h"
-
-TraceEvent trace_list[] = {
-EOF
-    stderr_event_num=0
-}
-
-linetoc_stderr()
-{
-    local name
-    name=$(get_name "$1")
-    cat <<EOF
-{.tp_name = "$name", .state=0},
-EOF
-    stderr_event_num=$(($stderr_event_num + 1))
-}
-
-linetoc_end_stderr()
-{
-    cat <<EOF
-};
-EOF
-}
-#END OF STDERR
-
-# Clean up after UST headers which pollute the namespace
-ust_clean_namespace() {
-    cat <<EOF
-#undef mutex_lock
-#undef mutex_unlock
-#undef inline
-#undef wmb
-EOF
-}
-
-linetoh_begin_ust()
-{
-    echo "#include <ust/tracepoint.h>"
-    ust_clean_namespace
-}
-
-linetoh_ust()
-{
-    local name args argnames
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-    argnames=$(get_argnames "$1", ",")
-
-    cat <<EOF
-DECLARE_TRACE(ust_$name, TP_PROTO($args), TP_ARGS($argnames));
-#define trace_$name trace_ust_$name
-EOF
-}
-
-linetoh_end_ust()
-{
-    return
-}
-
-linetoc_begin_ust()
-{
-    cat <<EOF
-#include <ust/marker.h>
-$(ust_clean_namespace)
-#include "trace.h"
-EOF
-}
-
-linetoc_ust()
-{
-    local name args argnames fmt
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-    argnames=$(get_argnames "$1", ",")
-    [ -z "$argnames" ] || argnames=", $argnames"
-    fmt=$(get_fmt "$1")
-
-    cat <<EOF
-DEFINE_TRACE(ust_$name);
-
-static void ust_${name}_probe($args)
-{
-    trace_mark(ust, $name, $fmt$argnames);
-}
-EOF
-
-    # Collect names for later
-    names="$names $name"
-}
-
-linetoc_end_ust()
-{
-    cat <<EOF
-static void __attribute__((constructor)) trace_init(void)
-{
-EOF
-
-    for name in $names; do
-        cat <<EOF
-    register_trace_ust_$name(ust_${name}_probe);
-EOF
-    done
-
-    echo "}"
-}
-
-linetoh_begin_dtrace()
-{
-    cat <<EOF
-#include "trace-dtrace.h"
-EOF
-}
-
-linetoh_dtrace()
-{
-    local name args argnames nameupper
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-    argnames=$(get_argnames "$1", ",")
-
-    nameupper=`echo $name | tr '[:lower:]' '[:upper:]'`
-
-    # Define an empty function for the trace event
-    cat <<EOF
-static inline void trace_$name($args) {
-    QEMU_${nameupper}($argnames);
-}
-EOF
-}
-
-linetoh_end_dtrace()
-{
-    return
-}
-
-linetoc_begin_dtrace()
-{
-    return
-}
-
-linetoc_dtrace()
-{
-    # No need for function definitions in dtrace backend
-    return
-}
-
-linetoc_end_dtrace()
-{
-    return
-}
-
-linetod_begin_dtrace()
-{
-    cat <<EOF
-provider qemu {
-EOF
-}
-
-linetod_dtrace()
-{
-    local name args
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-
-    # DTrace provider syntax expects foo() for empty
-    # params, not foo(void)
-    if [ "$args" = "void" ]; then
-       args=""
-    fi
-
-    # Define prototype for probe arguments
-    cat <<EOF
-        probe $name($args);
-EOF
-}
-
-linetod_end_dtrace()
-{
-    cat <<EOF
-};
-EOF
-}
-
-linetostap_begin_dtrace()
-{
-    return
-}
-
-linetostap_dtrace()
-{
-    local i arg name args arglist
-    name=$(get_name "$1")
-    args=$(get_args "$1")
-    arglist=$(get_argnames "$1", "")
-
-    # Define prototype for probe arguments
-    cat <<EOF
-probe $probeprefix.$name = process("$binary").mark("$name")
-{
-EOF
-
-    i=1
-    for arg in $arglist
-    do
-        # 'limit' is a reserved keyword
-        if [ "$arg" = "limit" ]; then
-          arg="_limit"
-        fi
-        cat <<EOF
-  $arg = \$arg$i;
-EOF
-        i="$((i+1))"
-    done
-
-    cat <<EOF
-}
-EOF
-}
-
-linetostap_end_dtrace()
-{
-    return
-}
-
-# Process stdin by calling begin, line, and end functions for the backend
-convert()
-{
-    local begin process_line end str name NAME enabled
-    begin="lineto$1_begin_$backend"
-    process_line="lineto$1_$backend"
-    end="lineto$1_end_$backend"
-
-    "$begin"
-
-    while read -r str; do
-        # Skip comments and empty lines
-        test -z "${str%%#*}" && continue
-
-        echo
-        # Process the line.  The nop backend handles disabled lines.
-        if has_property "$str" "disable"; then
-            "lineto$1_nop" "$str"
-            enabled=0
-        else
-            "$process_line" "$str"
-            enabled=1
-        fi
-        if [ "$1" = "h" ]; then
-            name=$(get_name "$str")
-            NAME=$(echo $name | tr '[:lower:]' '[:upper:]')
-            echo "#define TRACE_${NAME}_ENABLED ${enabled}"
-        fi
-    done
-
-    echo
-    "$end"
-}
-
-tracetoh()
-{
-    cat <<EOF
-#ifndef TRACE_H
-#define TRACE_H
-
-/* This file is autogenerated by tracetool, do not edit. */
-
-#include "qemu-common.h"
-EOF
-    convert h
-    echo "#endif /* TRACE_H */"
-}
-
-tracetoc()
-{
-    echo "/* This file is autogenerated by tracetool, do not edit. */"
-    convert c
-}
-
-tracetod()
-{
-    if [ $backend != "dtrace" ]; then
-       echo "DTrace probe generator not applicable to $backend backend"
-       exit 1
-    fi
-    echo "/* This file is autogenerated by tracetool, do not edit. */"
-    convert d
-}
-
-tracetostap()
-{
-    if [ $backend != "dtrace" ]; then
-       echo "SystemTAP tapset generator not applicable to $backend backend"
-       exit 1
-    fi
-    if [ -z "$binary" ]; then
-       echo "--binary is required for SystemTAP tapset generator"
-       exit 1
-    fi
-    if [ -z "$probeprefix" -a -z "$targettype" ]; then
-       echo "--target-type is required for SystemTAP tapset generator"
-       exit 1
-    fi
-    if [ -z "$probeprefix" -a -z "$targetarch" ]; then
-       echo "--target-arch is required for SystemTAP tapset generator"
-       exit 1
-    fi
-    if [ -z "$probeprefix" ]; then
-        probeprefix="qemu.$targettype.$targetarch";
-    fi
-    echo "/* This file is autogenerated by tracetool, do not edit. */"
-    convert stap
-}
-
-
-backend=
-output=
-binary=
-targettype=
-targetarch=
-probeprefix=
-
-
-until [ -z "$1" ]
-do
-  case "$1" in
-    "--nop" | "--simple" | "--stderr" | "--ust" | "--dtrace") backend="${1#--}" ;;
-
-    "--binary") shift ; binary="$1" ;;
-    "--target-arch") shift ; targetarch="$1" ;;
-    "--target-type") shift ; targettype="$1" ;;
-    "--probe-prefix") shift ; probeprefix="$1" ;;
-
-    "-h" | "-c" | "-d") output="${1#-}" ;;
-    "--stap") output="${1#--}" ;;
-
-    "--check-backend") exit 0 ;; # used by ./configure to test for backend
-
-    "--list-backends") # used by ./configure to list available backends
-          echo "nop simple stderr ust dtrace"
-          exit 0
-          ;;
-
-    *)
-      usage;;
-  esac
-  shift
-done
-
-if [ "$backend" = "" -o "$output" = "" ]; then
-  usage
-fi
-
-gen="traceto$output"
-"$gen"
-
-exit 0
diff --git a/scripts/tracetool.py b/scripts/tracetool.py
new file mode 100755
index 0000000..70bf79a
--- /dev/null
+++ b/scripts/tracetool.py
@@ -0,0 +1,110 @@ 
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Command-line wrapper for the tracetool machinery.
+"""
+
+__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
+__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@linux.vnet.ibm.com"
+
+
+import sys
+import getopt
+
+from tracetool import error_write, out
+import tracetool.backend
+import tracetool.format
+
+
+_SCRIPT = ""
+
+def error_opt(msg = None):
+    if msg is not None:
+        error_write("Error: " + msg + "\n")
+
+    backend_descr = "\n".join([ "    %-15s %s" % (n, d)
+                                for n,d in tracetool.backend.get_list() ])
+    format_descr = "\n".join([ "    %-15s %s" % (n, d)
+                               for n,d in tracetool.format.get_list() ])
+    error_write("""\
+Usage: %(script)s --format=<format> --backend=<backend> [<options>]
+
+Backends:
+%(backends)s
+
+Formats:
+%(formats)s
+
+Options:
+    --help                   This help message.
+    --list-backends          Print list of available backends.
+    --check-backend          Check if the given backend is valid.
+""" % {
+            "script" : _SCRIPT,
+            "backends" : backend_descr,
+            "formats" : format_descr,
+            })
+
+    if msg is None:
+        sys.exit(0)
+    else:
+        sys.exit(1)
+
+
+def main(args):
+    global _SCRIPT
+    _SCRIPT = args[0]
+
+    long_opts  = [ "backend=", "format=", "help", "list-backends", "check-backend" ]
+    long_opts += [ "binary=", "target-type=", "target-arch=", "probe-prefix=" ]
+
+    try:
+        opts, args = getopt.getopt(args[1:], "", long_opts)
+    except getopt.GetoptError as err:
+        error_opt(str(err))
+
+    check_backend = False
+    arg_backend = ""
+    arg_format = ""
+    for opt, arg in opts:
+        if opt == "--help":
+            error_opt()
+
+        elif opt == "--backend":
+            arg_backend = arg
+        elif opt == "--format":
+            arg_format = arg
+
+        elif opt == "--list-backends":
+            public_backends = tracetool.backend.get_list(only_public = True)
+            out(", ".join([ b for b,_ in public_backends ]))
+            sys.exit(0)
+        elif opt == "--check-backend":
+            check_backend = True
+
+        else:
+            error_opt("unhandled option: %s" % opt)
+
+    if arg_backend is None:
+        error_opt("backend not set")
+
+    if check_backend:
+        if tracetool.backend.exists(arg_backend):
+            sys.exit(0)
+        else:
+            sys.exit(1)
+
+    kwargs = {}
+
+    try:
+        tracetool.generate(sys.stdin, arg_format, arg_backend, **kwargs)
+    except tracetool.TracetoolError as e:
+        error_opt(str(e))
+
+if __name__ == "__main__":
+    main(sys.argv)
diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
new file mode 100644
index 0000000..955b6b8
--- /dev/null
+++ b/scripts/tracetool/__init__.py
@@ -0,0 +1,215 @@ 
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Machinery for generating tracing-related intermediate files.
+"""
+
+__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
+__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@linux.vnet.ibm.com"
+
+
+import re
+import sys
+
+import tracetool.format
+import tracetool.backend
+
+
+def error_write(*lines):
+    """Write a set of error lines."""
+    sys.stderr.writelines("\n".join(lines) + "\n")
+
+def error(*lines):
+    """Write a set of error lines and exit."""
+    error_write(*lines)
+    sys.exit(1)
+
+
+def out(*lines):
+    """Write a set of output lines."""
+    sys.stdout.writelines("\n".join(lines) + "\n")
+
+
+class Arguments:
+    """Event arguments description.
+
+    Parameters
+    ----------
+    arg_str : str
+        String describing the event arguments.
+    """
+
+    def __init__ (self, arg_str):
+        self._args = []
+        for arg in arg_str.split(","):
+            arg = arg.strip()
+            parts = arg.split()
+            head, sep, tail = parts[-1].rpartition("*")
+            parts = parts[:-1]
+            if tail == "void":
+                assert len(parts) == 0 and sep == ""
+                continue
+            arg_type = " ".join(parts + [ " ".join([head, sep]).strip() ]).strip()
+            self._args.append((arg_type, tail))
+
+    def __iter__(self):
+        """Iterate over the (type, name) pairs."""
+        return iter(self._args)
+
+    def __len__(self):
+        """Number of arguments."""
+        return len(self._args)
+
+    def __str__(self):
+        """String suitable for declaring function arguments."""
+        if len(self._args) == 0:
+            return "void"
+        else:
+            return ", ".join([ " ".join([t, n]) for t,n in self._args ])
+
+    def __repr__(self):
+        """Evaluable string representation for this object."""
+        return "Arguments(\"%s\")" % str(self)
+
+    def names(self):
+        """List of argument names."""
+        return [ name for _, name in self._args ]
+
+    def types(self):
+        """List of argument types."""
+        return [ type_ for type_, _ in self._args ]
+
+
+class Event(object):
+    """Event description.
+
+    Parameters
+    ----------
+    line : str
+        Line describing the event.
+
+    Attributes
+    ----------
+    name : str
+        The event name.
+    fmt : str
+        The event format string.
+    properties : set(str)
+        Properties of the event.
+    args : Arguments
+        The event arguments.
+    """
+
+    _CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?")
+
+    _VALID_PROPS = set(["disable"])
+
+    def __init__(self, line):
+        m = self._CRE.match(line)
+        assert m is not None
+        groups = m.groupdict('')
+        self.name = groups["name"]
+        self.fmt = groups["fmt"]
+        self.properties = groups["props"].split()
+        self.args = Arguments(groups["args"])
+
+        unknown_props = set(self.properties) - self._VALID_PROPS
+        if len(unknown_props) > 0:
+            raise ValueError("Unknown properties: %s" % ", ".join(unknown_props))
+
+    def __repr__(self):
+        """Evaluable string representation for this object."""
+        return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
+                                          self.name,
+                                          self.args,
+                                          self.fmt)
+
+def _read_events(fobj):
+    res = []
+    for line in fobj:
+        if not line.strip():
+            continue
+        if line.lstrip().startswith('#'):
+            continue
+        res.append(Event(line))
+    return res
+
+
+class TracetoolError (Exception):
+    """Exception for calls to generate."""
+    pass
+
+
+def try_import(mod_name, attr_name = None, attr_default = None):
+    """Try to import a module and get an attribute from it.
+
+    Parameters
+    ----------
+    mod_name : str
+        Module name.
+    attr_name : str, optional
+        Name of an attribute in the module.
+    attr_default : optional
+        Default value if the attribute does not exist in the module.
+
+    Returns
+    -------
+    A pair indicating whether the module could be imported and the module or
+    object or attribute value.
+    """
+    mod_name = mod_name.replace("-", "_")
+    try:
+        module = __import__(mod_name, fromlist=["__package__"])
+        if attr_name is None:
+            return True, module
+        return True, getattr(module, str(attr_name), attr_default)
+    except ImportError:
+        return False, None
+
+
+def generate(fevents, format, backend, **options):
+    """Generate the output for the given (format, backend) pair."""
+    # fix strange python error (UnboundLocalError tracetool)
+    import tracetool
+
+    if len(options) > 0:
+        raise ValueError("unknown options: " + ", ".join(options))
+
+    format = str(format)
+    if len(format) is 0:
+        raise TracetoolError("format not set")
+    mformat = format.replace("-", "_")
+    if not tracetool.format.exists(mformat):
+        raise TracetoolError("unknown format: %s" % format)
+
+    backend = str(backend)
+    if len(backend) is 0:
+        raise TracetoolError("backend not set")
+    mbackend = backend.replace("-", "_")
+    if not tracetool.backend.exists(mbackend):
+        raise TracetoolError("unknown backend: %s" % backend)
+
+    if not tracetool.backend.compatible(mbackend, mformat):
+        raise TracetoolError("backend '%s' not compatible with format '%s'" %
+                             (backend, format))
+
+    events = _read_events(fevents)
+
+    if backend == "nop":
+        ( e.properies.add("disable") for e in events )
+
+    tracetool.format.generate_begin(mformat, events)
+    tracetool.backend.generate("nop", format,
+                               [ e
+                                 for e in events
+                                 if "disable" in e.properties ])
+    tracetool.backend.generate(backend, format,
+                               [ e
+                                 for e in events
+                                 if "disable" not in e.properties ])
+    tracetool.format.generate_end(mformat, events)
diff --git a/scripts/tracetool/backend/__init__.py b/scripts/tracetool/backend/__init__.py
new file mode 100644
index 0000000..517da50
--- /dev/null
+++ b/scripts/tracetool/backend/__init__.py
@@ -0,0 +1,119 @@ 
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Backend management.
+
+
+Creating new backends
+---------------------
+
+A new backend named 'foo-bar' corresponds to Python module
+'tracetool/backend/foo_bar.py'.
+
+A backend module should provide a docstring, whose first non-empty line will be
+considered its short description.
+
+All backends must generate their contents through the 'tracetool.out' routine.
+
+
+Backend attributes
+------------------
+
+========= ====================================================================
+Attribute Description
+========= ====================================================================
+PUBLIC    If exists and is set to 'True', the backend is considered "public".
+========= ====================================================================
+
+
+Backend functions
+-----------------
+
+======== =======================================================================
+Function Description
+======== =======================================================================
+<format> Called to generate the format- and backend-specific code for each of
+         the specified events. If the function does not exist, the backend is
+         considered not compatible with the given format.
+======== =======================================================================
+"""
+
+__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
+__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@linux.vnet.ibm.com"
+
+
+import pkgutil
+
+import tracetool
+
+
+def get_list(only_public = False):
+    """Get a list of (name, description) pairs."""
+    res = [("nop", "Tracing disabled.")]
+    for _, modname, _ in pkgutil.iter_modules(tracetool.backend.__path__):
+        module = tracetool.try_import("tracetool.backend." + modname)
+
+        # just in case; should never fail unless non-module files are put there
+        if not module[0]:
+            continue
+        module = module[1]
+
+        public = getattr(module, "PUBLIC", False)
+        if only_public and not public:
+            continue
+
+        doc = module.__doc__
+        if doc is None:
+            doc = ""
+        doc = doc.strip().split("\n")[0]
+
+        name = modname.replace("_", "-")
+        res.append((name, doc))
+    return res
+
+
+def exists(name):
+    """Return whether the given backend exists."""
+    if len(name) == 0:
+        return False
+    name = name.replace("-", "_")
+    if name == "nop":
+        return True
+    return tracetool.try_import("tracetool.backend." + name)[1]
+
+
+def compatible(backend, format):
+    """Whether a backend is compatible with the given format."""
+    if not exists(backend):
+        raise ValueError("unknown backend: %s" % backend)
+
+    if backend == "nop":
+        return True
+    else:
+        func = tracetool.try_import("tracetool.backend." + backend,
+                                    format, None)[1]
+        return func is not None
+
+
+def _empty(events):
+    pass
+
+def generate(backend, format, events):
+    """Generate the per-event output for the given (backend, format) pair."""
+    if not compatible(backend, format):
+        raise ValueError("backend '%s' not compatible with format '%s'" %
+                         (backend, format))
+
+    if backend == "nop":
+        func = tracetool.try_import("tracetool.format." + format,
+                                    "nop", _empty)[1]
+    else:
+        func = tracetool.try_import("tracetool.backend." + backend,
+                                    format, None)[1]
+
+    func(events)
diff --git a/scripts/tracetool/format/__init__.py b/scripts/tracetool/format/__init__.py
new file mode 100644
index 0000000..174777f
--- /dev/null
+++ b/scripts/tracetool/format/__init__.py
@@ -0,0 +1,96 @@ 
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+Format management.
+
+
+Creating new formats
+--------------------
+
+A new format named 'foo-bar' corresponds to Python module
+'tracetool/format/foo_bar.py'.
+
+A format module should provide a docstring, whose first non-empty line will be
+considered its short description.
+
+All formats must generate their contents through the 'tracetool.out' routine.
+
+
+Format functions
+----------------
+
+All the following functions are optional, and no output will be generated if
+they do not exist.
+
+======== =======================================================================
+Function Description
+======== =======================================================================
+begin    Called to generate the format-specific file header.
+end      Called to generate the format-specific file footer.
+nop      Called to generate the per-event contents when the event is disabled or
+         the selected backend is 'nop'.
+======== =======================================================================
+"""
+
+__author__     = "Lluís Vilanova <vilanova@ac.upc.edu>"
+__copyright__  = "Copyright 2012, Lluís Vilanova <vilanova@ac.upc.edu>"
+__license__    = "GPL version 2 or (at your option) any later version"
+
+__maintainer__ = "Stefan Hajnoczi"
+__email__      = "stefanha@linux.vnet.ibm.com"
+
+
+import pkgutil
+
+import tracetool
+
+
+def get_list():
+    """Get a list of (name, description) pairs."""
+    res = []
+    for _, modname, _ in pkgutil.iter_modules(tracetool.format.__path__):
+        module = tracetool.try_import("tracetool.format." + modname)
+
+        # just in case; should never fail unless non-module files are put there
+        if not module[0]:
+            continue
+        module = module[1]
+
+        doc = module.__doc__
+        if doc is None:
+            doc = ""
+        doc = doc.strip().split("\n")[0]
+
+        name = modname.replace("_", "-")
+        res.append((name, doc))
+    return res
+
+
+def exists(name):
+    """Return whether the given format exists."""
+    if len(name) == 0:
+        return False
+    return tracetool.try_import("tracetool.format." + name)[1]
+
+
+def _empty(events):
+    pass
+
+def generate_begin(name, events):
+    """Generate the header of the format-specific file."""
+    if not exists(name):
+        raise ValueError("unknown format: %s" % name)
+
+    func = tracetool.try_import("tracetool.format." + name,
+                                "begin", _empty)[1]
+    func(events)
+
+def generate_end(name, events):
+    """Generate the footer of the format-specific file."""
+    if not exists(name):
+        raise ValueError("unknown format: %s" % name)
+
+    func = tracetool.try_import("tracetool.format." + name,
+                                "end", _empty)[1]
+    func(events)