qemu-e2k/scripts/qapi-commands.py

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#
# QAPI command marshaller generator
#
# Copyright IBM, Corp. 2011
# Copyright (C) 2014-2015 Red Hat, Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Michael Roth <mdroth@linux.vnet.ibm.com>
qapi: Replace uncommon use of the error API by the common one We commonly use the error API like this: err = NULL; foo(..., &err); if (err) { goto out; } bar(..., &err); Every error source is checked separately. The second function is only called when the first one succeeds. Both functions are free to pass their argument to error_set(). Because error_set() asserts no error has been set, this effectively means they must not be called with an error set. The qapi-generated code uses the error API differently: // *errp was initialized to NULL somewhere up the call chain frob(..., errp); gnat(..., errp); Errors accumulate in *errp: first error wins, subsequent errors get dropped. To make this work, the second function does nothing when called with an error set. Requires non-null errp, or else the second function can't see the first one fail. This usage has also bled into visitor tests, and two device model object property getters rtc_get_date() and balloon_stats_get_all(). With the "accumulate" technique, you need fewer error checks in callers, and buy that with an error check in every callee. Can be nice. However, mixing the two techniques is confusing. You can't use the "accumulate" technique with functions designed for the "check separately" technique. You can use the "check separately" technique with functions designed for the "accumulate" technique, but then error_set() can't catch you setting an error more than once. Standardize on the "check separately" technique for now, because it's overwhelmingly prevalent. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-07 09:53:54 +02:00
# Markus Armbruster <armbru@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
from qapi import *
qapi: Replace uncommon use of the error API by the common one We commonly use the error API like this: err = NULL; foo(..., &err); if (err) { goto out; } bar(..., &err); Every error source is checked separately. The second function is only called when the first one succeeds. Both functions are free to pass their argument to error_set(). Because error_set() asserts no error has been set, this effectively means they must not be called with an error set. The qapi-generated code uses the error API differently: // *errp was initialized to NULL somewhere up the call chain frob(..., errp); gnat(..., errp); Errors accumulate in *errp: first error wins, subsequent errors get dropped. To make this work, the second function does nothing when called with an error set. Requires non-null errp, or else the second function can't see the first one fail. This usage has also bled into visitor tests, and two device model object property getters rtc_get_date() and balloon_stats_get_all(). With the "accumulate" technique, you need fewer error checks in callers, and buy that with an error check in every callee. Can be nice. However, mixing the two techniques is confusing. You can't use the "accumulate" technique with functions designed for the "check separately" technique. You can use the "check separately" technique with functions designed for the "accumulate" technique, but then error_set() can't catch you setting an error more than once. Standardize on the "check separately" technique for now, because it's overwhelmingly prevalent. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-07 09:53:54 +02:00
import re
def gen_command_decl(name, arg_type, ret_type):
return mcgen('''
%(c_type)s qmp_%(c_name)s(%(params)s);
''',
c_type=(ret_type and ret_type.c_type()) or 'void',
c_name=c_name(name),
params=gen_params(arg_type, 'Error **errp'))
def gen_call(name, arg_type, ret_type):
ret = ''
argstr = ''
if arg_type:
for memb in arg_type.members:
if memb.optional:
argstr += 'has_%s, ' % c_name(memb.name)
argstr += '%s, ' % c_name(memb.name)
lhs = ''
if ret_type:
lhs = 'retval = '
ret = mcgen('''
%(lhs)sqmp_%(c_name)s(%(args)s&err);
''',
c_name=c_name(name), args=argstr, lhs=lhs)
if ret_type:
ret += gen_err_check()
ret += mcgen('''
qmp_marshal_output_%(c_name)s(retval, ret, &err);
''',
c_name=ret_type.c_name())
return ret
def gen_marshal_vars(arg_type, ret_type):
ret = mcgen('''
Error *err = NULL;
''')
if ret_type:
ret += mcgen('''
%(c_type)s retval;
''',
c_type=ret_type.c_type())
if arg_type:
ret += mcgen('''
QmpInputVisitor *qiv = qmp_input_visitor_new_strict(QOBJECT(args));
QapiDeallocVisitor *qdv;
Visitor *v;
''')
for memb in arg_type.members:
if memb.optional:
ret += mcgen('''
bool has_%(c_name)s = false;
''',
c_name=c_name(memb.name))
ret += mcgen('''
%(c_type)s %(c_name)s = %(c_null)s;
''',
c_name=c_name(memb.name),
c_type=memb.type.c_type(),
c_null=memb.type.c_null())
ret += '\n'
else:
ret += mcgen('''
(void)args;
''')
return ret
def gen_marshal_input_visit(arg_type, dealloc=False):
ret = ''
qapi: qapi-commands: fix possible leaks on visitor dealloc In qmp-marshal.c the dealloc visitor calls use the same errp pointer of the input visitor calls. This means that if any of the input visitor calls fails, then the dealloc visitor will return early, before freeing the object's memory. Here's an example, consider this code: int qmp_marshal_input_block_passwd(Monitor *mon, const QDict *qdict, QObject **ret) { [...] char * device = NULL; char * password = NULL; mi = qmp_input_visitor_new_strict(QOBJECT(args)); v = qmp_input_get_visitor(mi); visit_type_str(v, &device, "device", errp); visit_type_str(v, &password, "password", errp); qmp_input_visitor_cleanup(mi); if (error_is_set(errp)) { goto out; } qmp_block_passwd(device, password, errp); out: md = qapi_dealloc_visitor_new(); v = qapi_dealloc_get_visitor(md); visit_type_str(v, &device, "device", errp); visit_type_str(v, &password, "password", errp); qapi_dealloc_visitor_cleanup(md); [...] return 0; } Consider errp != NULL when the out label is reached, we're going to leak device and password. This patch fixes this by always passing errp=NULL for dealloc visitors, meaning that we always try to free them regardless of any previous failure. The above example would then be: out: md = qapi_dealloc_visitor_new(); v = qapi_dealloc_get_visitor(md); visit_type_str(v, &device, "device", NULL); visit_type_str(v, &password, "password", NULL); qapi_dealloc_visitor_cleanup(md); Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Laszlo Ersek <lersek@redhat.com> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
2013-07-11 20:26:56 +02:00
if not arg_type:
return ret
if dealloc:
ret += mcgen('''
qmp_input_visitor_cleanup(qiv);
qdv = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(qdv);
''')
else:
ret += mcgen('''
v = qmp_input_get_visitor(qiv);
''')
ret += gen_visit_fields(arg_type.members, skiperr=dealloc)
if dealloc:
ret += mcgen('''
qapi_dealloc_visitor_cleanup(qdv);
''')
return ret
def gen_marshal_output(ret_type):
return mcgen('''
static void qmp_marshal_output_%(c_name)s(%(c_type)s ret_in, QObject **ret_out, Error **errp)
{
Error *err = NULL;
QmpOutputVisitor *qov = qmp_output_visitor_new();
QapiDeallocVisitor *qdv;
Visitor *v;
v = qmp_output_get_visitor(qov);
visit_type_%(c_name)s(v, &ret_in, "unused", &err);
if (err) {
qapi: Replace uncommon use of the error API by the common one We commonly use the error API like this: err = NULL; foo(..., &err); if (err) { goto out; } bar(..., &err); Every error source is checked separately. The second function is only called when the first one succeeds. Both functions are free to pass their argument to error_set(). Because error_set() asserts no error has been set, this effectively means they must not be called with an error set. The qapi-generated code uses the error API differently: // *errp was initialized to NULL somewhere up the call chain frob(..., errp); gnat(..., errp); Errors accumulate in *errp: first error wins, subsequent errors get dropped. To make this work, the second function does nothing when called with an error set. Requires non-null errp, or else the second function can't see the first one fail. This usage has also bled into visitor tests, and two device model object property getters rtc_get_date() and balloon_stats_get_all(). With the "accumulate" technique, you need fewer error checks in callers, and buy that with an error check in every callee. Can be nice. However, mixing the two techniques is confusing. You can't use the "accumulate" technique with functions designed for the "check separately" technique. You can use the "check separately" technique with functions designed for the "accumulate" technique, but then error_set() can't catch you setting an error more than once. Standardize on the "check separately" technique for now, because it's overwhelmingly prevalent. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-07 09:53:54 +02:00
goto out;
}
*ret_out = qmp_output_get_qobject(qov);
qapi: Replace uncommon use of the error API by the common one We commonly use the error API like this: err = NULL; foo(..., &err); if (err) { goto out; } bar(..., &err); Every error source is checked separately. The second function is only called when the first one succeeds. Both functions are free to pass their argument to error_set(). Because error_set() asserts no error has been set, this effectively means they must not be called with an error set. The qapi-generated code uses the error API differently: // *errp was initialized to NULL somewhere up the call chain frob(..., errp); gnat(..., errp); Errors accumulate in *errp: first error wins, subsequent errors get dropped. To make this work, the second function does nothing when called with an error set. Requires non-null errp, or else the second function can't see the first one fail. This usage has also bled into visitor tests, and two device model object property getters rtc_get_date() and balloon_stats_get_all(). With the "accumulate" technique, you need fewer error checks in callers, and buy that with an error check in every callee. Can be nice. However, mixing the two techniques is confusing. You can't use the "accumulate" technique with functions designed for the "check separately" technique. You can use the "check separately" technique with functions designed for the "accumulate" technique, but then error_set() can't catch you setting an error more than once. Standardize on the "check separately" technique for now, because it's overwhelmingly prevalent. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-07 09:53:54 +02:00
out:
error_propagate(errp, err);
qmp_output_visitor_cleanup(qov);
qdv = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(qdv);
visit_type_%(c_name)s(v, &ret_in, "unused", NULL);
qapi_dealloc_visitor_cleanup(qdv);
}
''',
c_type=ret_type.c_type(), c_name=ret_type.c_name())
def gen_marshal_proto(name):
ret = 'void qmp_marshal_%s(QDict *args, QObject **ret, Error **errp)' % c_name(name)
qmp: Wean off qerror_report() The traditional QMP command handler interface int qmp_FOO(Monitor *mon, const QDict *params, QObject **ret_data); doesn't provide for returning an Error object. Instead, the handler is expected to stash it in the monitor with qerror_report(). When we rebased QMP on top of QAPI, we didn't change this interface. Instead, commit 776574d introduced "middle mode" as a temporary aid for converting existing QMP commands to QAPI one by one. More than three years later, we're still using it. Middle mode has two effects: * Instead of the native input marshallers static void qmp_marshal_input_FOO(QDict *, QObject **, Error **) it generates input marshallers conforming to the traditional QMP command handler interface. * It suppresses generation of code to register them with qmp_register_command() This permits giving them internal linkage. As long as we need qmp-commands.hx, we can't use the registry behind qmp_register_command(), so the latter has to stay for now. The former has to go to get rid of qerror_report(). Changing all QMP commands to fit the QAPI mold in one go was impractical back when we started, but by now there are just a few stragglers left: do_qmp_capabilities(), qmp_qom_set(), qmp_qom_get(), qmp_object_add(), qmp_netdev_add(), do_device_add(). Switch middle mode to generate native input marshallers, and adapt the stragglers. Simplifies both the monitor code and the stragglers. Rename do_qmp_capabilities() to qmp_capabilities(), and do_device_add() to qmp_device_add, because that's how QMP command handlers are named today. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-03-13 17:25:50 +01:00
if not middle_mode:
ret = 'static ' + ret
qmp: Wean off qerror_report() The traditional QMP command handler interface int qmp_FOO(Monitor *mon, const QDict *params, QObject **ret_data); doesn't provide for returning an Error object. Instead, the handler is expected to stash it in the monitor with qerror_report(). When we rebased QMP on top of QAPI, we didn't change this interface. Instead, commit 776574d introduced "middle mode" as a temporary aid for converting existing QMP commands to QAPI one by one. More than three years later, we're still using it. Middle mode has two effects: * Instead of the native input marshallers static void qmp_marshal_input_FOO(QDict *, QObject **, Error **) it generates input marshallers conforming to the traditional QMP command handler interface. * It suppresses generation of code to register them with qmp_register_command() This permits giving them internal linkage. As long as we need qmp-commands.hx, we can't use the registry behind qmp_register_command(), so the latter has to stay for now. The former has to go to get rid of qerror_report(). Changing all QMP commands to fit the QAPI mold in one go was impractical back when we started, but by now there are just a few stragglers left: do_qmp_capabilities(), qmp_qom_set(), qmp_qom_get(), qmp_object_add(), qmp_netdev_add(), do_device_add(). Switch middle mode to generate native input marshallers, and adapt the stragglers. Simplifies both the monitor code and the stragglers. Rename do_qmp_capabilities() to qmp_capabilities(), and do_device_add() to qmp_device_add, because that's how QMP command handlers are named today. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-03-13 17:25:50 +01:00
return ret
def gen_marshal_decl(name):
return mcgen('''
%(proto)s;
''',
proto=gen_marshal_proto(name))
def gen_marshal(name, arg_type, ret_type):
ret = mcgen('''
%(proto)s
{
''',
proto=gen_marshal_proto(name))
ret += gen_marshal_vars(arg_type, ret_type)
ret += gen_marshal_input_visit(arg_type)
ret += gen_call(name, arg_type, ret_type)
# 'goto out' produced by gen_marshal_input_visit->gen_visit_fields()
# for each arg_type member, and by gen_call() for ret_type
if (arg_type and arg_type.members) or ret_type:
qapi: Replace uncommon use of the error API by the common one We commonly use the error API like this: err = NULL; foo(..., &err); if (err) { goto out; } bar(..., &err); Every error source is checked separately. The second function is only called when the first one succeeds. Both functions are free to pass their argument to error_set(). Because error_set() asserts no error has been set, this effectively means they must not be called with an error set. The qapi-generated code uses the error API differently: // *errp was initialized to NULL somewhere up the call chain frob(..., errp); gnat(..., errp); Errors accumulate in *errp: first error wins, subsequent errors get dropped. To make this work, the second function does nothing when called with an error set. Requires non-null errp, or else the second function can't see the first one fail. This usage has also bled into visitor tests, and two device model object property getters rtc_get_date() and balloon_stats_get_all(). With the "accumulate" technique, you need fewer error checks in callers, and buy that with an error check in every callee. Can be nice. However, mixing the two techniques is confusing. You can't use the "accumulate" technique with functions designed for the "check separately" technique. You can use the "check separately" technique with functions designed for the "accumulate" technique, but then error_set() can't catch you setting an error more than once. Standardize on the "check separately" technique for now, because it's overwhelmingly prevalent. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-07 09:53:54 +02:00
ret += mcgen('''
out:
''')
ret += mcgen('''
error_propagate(errp, err);
''')
ret += gen_marshal_input_visit(arg_type, dealloc=True)
ret += mcgen('''
qmp: Wean off qerror_report() The traditional QMP command handler interface int qmp_FOO(Monitor *mon, const QDict *params, QObject **ret_data); doesn't provide for returning an Error object. Instead, the handler is expected to stash it in the monitor with qerror_report(). When we rebased QMP on top of QAPI, we didn't change this interface. Instead, commit 776574d introduced "middle mode" as a temporary aid for converting existing QMP commands to QAPI one by one. More than three years later, we're still using it. Middle mode has two effects: * Instead of the native input marshallers static void qmp_marshal_input_FOO(QDict *, QObject **, Error **) it generates input marshallers conforming to the traditional QMP command handler interface. * It suppresses generation of code to register them with qmp_register_command() This permits giving them internal linkage. As long as we need qmp-commands.hx, we can't use the registry behind qmp_register_command(), so the latter has to stay for now. The former has to go to get rid of qerror_report(). Changing all QMP commands to fit the QAPI mold in one go was impractical back when we started, but by now there are just a few stragglers left: do_qmp_capabilities(), qmp_qom_set(), qmp_qom_get(), qmp_object_add(), qmp_netdev_add(), do_device_add(). Switch middle mode to generate native input marshallers, and adapt the stragglers. Simplifies both the monitor code and the stragglers. Rename do_qmp_capabilities() to qmp_capabilities(), and do_device_add() to qmp_device_add, because that's how QMP command handlers are named today. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
2015-03-13 17:25:50 +01:00
}
''')
return ret
def gen_register_command(name, success_response):
options = 'QCO_NO_OPTIONS'
if not success_response:
options = 'QCO_NO_SUCCESS_RESP'
ret = mcgen('''
qmp_register_command("%(name)s", qmp_marshal_%(c_name)s, %(opts)s);
''',
name=name, c_name=c_name(name),
opts=options)
return ret
def gen_registry(registry):
ret = mcgen('''
static void qmp_init_marshal(void)
{
''')
ret += registry
ret += mcgen('''
}
qapi_init(qmp_init_marshal);
''')
return ret
class QAPISchemaGenCommandVisitor(QAPISchemaVisitor):
def __init__(self):
self.decl = None
self.defn = None
self._regy = None
self._visited_ret_types = None
def visit_begin(self, schema):
self.decl = ''
self.defn = ''
self._regy = ''
self._visited_ret_types = set()
def visit_end(self):
if not middle_mode:
self.defn += gen_registry(self._regy)
self._regy = None
self._visited_ret_types = None
def visit_command(self, name, info, arg_type, ret_type,
gen, success_response):
if not gen:
return
self.decl += gen_command_decl(name, arg_type, ret_type)
if ret_type and ret_type not in self._visited_ret_types:
self._visited_ret_types.add(ret_type)
self.defn += gen_marshal_output(ret_type)
if middle_mode:
self.decl += gen_marshal_decl(name)
self.defn += gen_marshal(name, arg_type, ret_type)
if not middle_mode:
self._regy += gen_register_command(name, success_response)
middle_mode = False
(input_file, output_dir, do_c, do_h, prefix, opts) = \
parse_command_line("m", ["middle"])
for o, a in opts:
if o in ("-m", "--middle"):
middle_mode = True
c_comment = '''
/*
* schema-defined QMP->QAPI command dispatch
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
h_comment = '''
/*
* schema-defined QAPI function prototypes
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
'''
(fdef, fdecl) = open_output(output_dir, do_c, do_h, prefix,
'qmp-marshal.c', 'qmp-commands.h',
c_comment, h_comment)
fdef.write(mcgen('''
#include "qemu-common.h"
#include "qemu/module.h"
#include "qapi/qmp/types.h"
#include "qapi/qmp/dispatch.h"
#include "qapi/visitor.h"
#include "qapi/qmp-output-visitor.h"
#include "qapi/qmp-input-visitor.h"
#include "qapi/dealloc-visitor.h"
#include "%(prefix)sqapi-types.h"
#include "%(prefix)sqapi-visit.h"
#include "%(prefix)sqmp-commands.h"
''',
prefix=prefix))
fdecl.write(mcgen('''
#include "%(prefix)sqapi-types.h"
#include "qapi/qmp/qdict.h"
#include "qapi/error.h"
''',
prefix=prefix))
schema = QAPISchema(input_file)
gen = QAPISchemaGenCommandVisitor()
schema.visit(gen)
fdef.write(gen.defn)
fdecl.write(gen.decl)
close_output(fdef, fdecl)