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qemu/scripts/qapi-commands.py
Michael Roth fc13d93726 qapi: zero-initialize all QMP command parameters 
In general QMP command parameter values are specified by consumers of the
QMP/HMP interface, but in the case of optional parameters these values may
be left uninitialized.

It is considered a bug for code to make use of optional parameters that have
not been flagged as being present by the marshalling code (via corresponding
has_<parameter> parameter), however our marshalling code will still pass
these uninitialized values on to the corresponding QMP function (to then
be ignored). Some compilers (clang in particular) consider this unsafe
however, and generate warnings as a result. As reported by Peter Maydell:

  This is something clang's -fsanitize=undefined spotted. The
  code generated by qapi-commands.py in qmp-marshal.c for
  qmp_marshal_* functions where there are some optional
  arguments looks like this:

      bool has_force = false;
      bool force;

      mi = qmp_input_visitor_new_strict(QOBJECT(args));
      v = qmp_input_get_visitor(mi);
      visit_type_str(v, &device, "device", errp);
      visit_start_optional(v, &has_force, "force", errp);
      if (has_force) {
          visit_type_bool(v, &force, "force", errp);
      }
      visit_end_optional(v, errp);
      qmp_input_visitor_cleanup(mi);

      if (error_is_set(errp)) {
          goto out;
      }
      qmp_eject(device, has_force, force, errp);

  In the case where has_force is false, we never initialize
  force, but then we use it by passing it to qmp_eject.
  I imagine we don't then actually use the value, but clang
  complains in particular for 'bool' variables because the value
  that ends up being loaded from memory for 'force' is not either
  0 or 1 (being uninitialized stack contents).

Fix this by initializing all QMP command parameters to {0} in the
marshalling code prior to passing them on to the QMP functions.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2014-05-21 09:25:31 -04:00

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#
# QAPI command marshaller generator
#
# Copyright IBM, Corp. 2011
# Copyright (C) 2014 Red Hat, Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Michael Roth <mdroth@linux.vnet.ibm.com>
# 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 ordereddict import OrderedDict
from qapi import *
import re
import sys
import os
import getopt
import errno
def type_visitor(name):
if type(name) == list:
return 'visit_type_%sList' % name[0]
else:
return 'visit_type_%s' % name
def generate_command_decl(name, args, ret_type):
arglist=""
for argname, argtype, optional, structured in parse_args(args):
argtype = c_type(argtype)
if argtype == "char *":
argtype = "const char *"
if optional:
arglist += "bool has_%s, " % c_var(argname)
arglist += "%s %s, " % (argtype, c_var(argname))
return mcgen('''
%(ret_type)s qmp_%(name)s(%(args)sError **errp);
''',
ret_type=c_type(ret_type), name=c_fun(name), args=arglist).strip()
def gen_err_check(errvar):
if errvar:
return mcgen('''
if (local_err) {
goto out;
}
''')
return ''
def gen_sync_call(name, args, ret_type, indent=0):
ret = ""
arglist=""
retval=""
if ret_type:
retval = "retval = "
for argname, argtype, optional, structured in parse_args(args):
if optional:
arglist += "has_%s, " % c_var(argname)
arglist += "%s, " % (c_var(argname))
push_indent(indent)
ret = mcgen('''
%(retval)sqmp_%(name)s(%(args)s&local_err);
''',
name=c_fun(name), args=arglist, retval=retval).rstrip()
if ret_type:
ret += "\n" + gen_err_check('local_err')
ret += "\n" + mcgen(''''
%(marshal_output_call)s
''',
marshal_output_call=gen_marshal_output_call(name, ret_type)).rstrip()
pop_indent(indent)
return ret.rstrip()
def gen_marshal_output_call(name, ret_type):
if not ret_type:
return ""
return "qmp_marshal_output_%s(retval, ret, &local_err);" % c_fun(name)
def gen_visitor_input_containers_decl(args, obj):
ret = ""
push_indent()
if len(args) > 0:
ret += mcgen('''
QmpInputVisitor *mi = qmp_input_visitor_new_strict(%(obj)s);
QapiDeallocVisitor *md;
Visitor *v;
''',
obj=obj)
pop_indent()
return ret.rstrip()
def gen_visitor_input_vars_decl(args):
ret = ""
push_indent()
for argname, argtype, optional, structured in parse_args(args):
if optional:
ret += mcgen('''
bool has_%(argname)s = false;
''',
argname=c_var(argname))
if c_type(argtype).endswith("*"):
ret += mcgen('''
%(argtype)s %(argname)s = NULL;
''',
argname=c_var(argname), argtype=c_type(argtype))
else:
ret += mcgen('''
%(argtype)s %(argname)s = {0};
''',
argname=c_var(argname), argtype=c_type(argtype))
pop_indent()
return ret.rstrip()
def gen_visitor_input_block(args, dealloc=False):
ret = ""
errparg = '&local_err'
errarg = 'local_err'
if len(args) == 0:
return ret
push_indent()
if dealloc:
errparg = 'NULL'
errarg = None;
ret += mcgen('''
qmp_input_visitor_cleanup(mi);
md = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(md);
''')
else:
ret += mcgen('''
v = qmp_input_get_visitor(mi);
''')
for argname, argtype, optional, structured in parse_args(args):
if optional:
ret += mcgen('''
visit_optional(v, &has_%(c_name)s, "%(name)s", %(errp)s);
''',
c_name=c_var(argname), name=argname, errp=errparg)
ret += gen_err_check(errarg)
ret += mcgen('''
if (has_%(c_name)s) {
''',
c_name=c_var(argname))
push_indent()
ret += mcgen('''
%(visitor)s(v, &%(c_name)s, "%(name)s", %(errp)s);
''',
c_name=c_var(argname), name=argname, argtype=argtype,
visitor=type_visitor(argtype), errp=errparg)
ret += gen_err_check(errarg)
if optional:
pop_indent()
ret += mcgen('''
}
''')
if dealloc:
ret += mcgen('''
qapi_dealloc_visitor_cleanup(md);
''')
pop_indent()
return ret.rstrip()
def gen_marshal_output(name, args, ret_type, middle_mode):
if not ret_type:
return ""
ret = mcgen('''
static void qmp_marshal_output_%(c_name)s(%(c_ret_type)s ret_in, QObject **ret_out, Error **errp)
{
Error *local_err = NULL;
QmpOutputVisitor *mo = qmp_output_visitor_new();
QapiDeallocVisitor *md;
Visitor *v;
v = qmp_output_get_visitor(mo);
%(visitor)s(v, &ret_in, "unused", &local_err);
if (local_err) {
goto out;
}
*ret_out = qmp_output_get_qobject(mo);
out:
error_propagate(errp, local_err);
qmp_output_visitor_cleanup(mo);
md = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(md);
%(visitor)s(v, &ret_in, "unused", NULL);
qapi_dealloc_visitor_cleanup(md);
}
''',
c_ret_type=c_type(ret_type), c_name=c_fun(name),
visitor=type_visitor(ret_type))
return ret
def gen_marshal_input_decl(name, args, ret_type, middle_mode):
if middle_mode:
return 'int qmp_marshal_input_%s(Monitor *mon, const QDict *qdict, QObject **ret)' % c_fun(name)
else:
return 'static void qmp_marshal_input_%s(QDict *args, QObject **ret, Error **errp)' % c_fun(name)
def gen_marshal_input(name, args, ret_type, middle_mode):
hdr = gen_marshal_input_decl(name, args, ret_type, middle_mode)
ret = mcgen('''
%(header)s
{
Error *local_err = NULL;
''',
header=hdr)
if middle_mode:
ret += mcgen('''
QDict *args = (QDict *)qdict;
''')
if ret_type:
if c_type(ret_type).endswith("*"):
retval = " %s retval = NULL;" % c_type(ret_type)
else:
retval = " %s retval;" % c_type(ret_type)
ret += mcgen('''
%(retval)s
''',
retval=retval)
if len(args) > 0:
ret += mcgen('''
%(visitor_input_containers_decl)s
%(visitor_input_vars_decl)s
%(visitor_input_block)s
''',
visitor_input_containers_decl=gen_visitor_input_containers_decl(args, "QOBJECT(args)"),
visitor_input_vars_decl=gen_visitor_input_vars_decl(args),
visitor_input_block=gen_visitor_input_block(args))
else:
ret += mcgen('''
(void)args;
''')
ret += mcgen('''
%(sync_call)s
''',
sync_call=gen_sync_call(name, args, ret_type, indent=4))
if re.search('^ *goto out\\;', ret, re.MULTILINE):
ret += mcgen('''
out:
''')
if not middle_mode:
ret += mcgen('''
error_propagate(errp, local_err);
''')
ret += mcgen('''
%(visitor_input_block_cleanup)s
''',
visitor_input_block_cleanup=gen_visitor_input_block(args,
dealloc=True))
if middle_mode:
ret += mcgen('''
if (local_err) {
qerror_report_err(local_err);
error_free(local_err);
return -1;
}
return 0;
''')
else:
ret += mcgen('''
return;
''')
ret += mcgen('''
}
''')
return ret
def option_value_matches(opt, val, cmd):
if opt in cmd and cmd[opt] == val:
return True
return False
def gen_registry(commands):
registry=""
push_indent()
for cmd in commands:
options = 'QCO_NO_OPTIONS'
if option_value_matches('success-response', 'no', cmd):
options = 'QCO_NO_SUCCESS_RESP'
registry += mcgen('''
qmp_register_command("%(name)s", qmp_marshal_input_%(c_name)s, %(opts)s);
''',
name=cmd['command'], c_name=c_fun(cmd['command']),
opts=options)
pop_indent()
ret = mcgen('''
static void qmp_init_marshal(void)
{
%(registry)s
}
qapi_init(qmp_init_marshal);
''',
registry=registry.rstrip())
return ret
def gen_command_decl_prologue(header, guard, prefix=""):
ret = mcgen('''
/* THIS FILE IS AUTOMATICALLY GENERATED, DO NOT MODIFY */
/*
* 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.
*
*/
#ifndef %(guard)s
#define %(guard)s
#include "%(prefix)sqapi-types.h"
#include "qapi/qmp/qdict.h"
#include "qapi/error.h"
''',
header=basename(header), guard=guardname(header), prefix=prefix)
return ret
def gen_command_def_prologue(prefix="", proxy=False):
ret = mcgen('''
/* THIS FILE IS AUTOMATICALLY GENERATED, DO NOT MODIFY */
/*
* 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.
*
*/
#include "qemu-common.h"
#include "qemu/module.h"
#include "qapi/qmp/qerror.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"
''',
prefix=prefix)
if not proxy:
ret += '#include "%sqmp-commands.h"' % prefix
return ret + "\n\n"
try:
opts, args = getopt.gnu_getopt(sys.argv[1:], "chp:i:o:m",
["source", "header", "prefix=",
"input-file=", "output-dir=",
"type=", "middle"])
except getopt.GetoptError, err:
print str(err)
sys.exit(1)
output_dir = ""
prefix = ""
dispatch_type = "sync"
c_file = 'qmp-marshal.c'
h_file = 'qmp-commands.h'
middle_mode = False
do_c = False
do_h = False
for o, a in opts:
if o in ("-p", "--prefix"):
prefix = a
elif o in ("-i", "--input-file"):
input_file = a
elif o in ("-o", "--output-dir"):
output_dir = a + "/"
elif o in ("-t", "--type"):
dispatch_type = a
elif o in ("-m", "--middle"):
middle_mode = True
elif o in ("-c", "--source"):
do_c = True
elif o in ("-h", "--header"):
do_h = True
if not do_c and not do_h:
do_c = True
do_h = True
c_file = output_dir + prefix + c_file
h_file = output_dir + prefix + h_file
def maybe_open(really, name, opt):
if really:
return open(name, opt)
else:
import StringIO
return StringIO.StringIO()
try:
os.makedirs(output_dir)
except os.error, e:
if e.errno != errno.EEXIST:
raise
exprs = parse_schema(input_file)
commands = filter(lambda expr: expr.has_key('command'), exprs)
commands = filter(lambda expr: not expr.has_key('gen'), commands)
if dispatch_type == "sync":
fdecl = maybe_open(do_h, h_file, 'w')
fdef = maybe_open(do_c, c_file, 'w')
ret = gen_command_decl_prologue(header=basename(h_file), guard=guardname(h_file), prefix=prefix)
fdecl.write(ret)
ret = gen_command_def_prologue(prefix=prefix)
fdef.write(ret)
for cmd in commands:
arglist = []
ret_type = None
if cmd.has_key('data'):
arglist = cmd['data']
if cmd.has_key('returns'):
ret_type = cmd['returns']
ret = generate_command_decl(cmd['command'], arglist, ret_type) + "\n"
fdecl.write(ret)
if ret_type:
ret = gen_marshal_output(cmd['command'], arglist, ret_type, middle_mode) + "\n"
fdef.write(ret)
if middle_mode:
fdecl.write('%s;\n' % gen_marshal_input_decl(cmd['command'], arglist, ret_type, middle_mode))
ret = gen_marshal_input(cmd['command'], arglist, ret_type, middle_mode) + "\n"
fdef.write(ret)
fdecl.write("\n#endif\n");
if not middle_mode:
ret = gen_registry(commands)
fdef.write(ret)
fdef.flush()
fdef.close()
fdecl.flush()
fdecl.close()
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