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qemu/scripts/qapi-commands.py
Luiz Capitulino 8f91ad8a1b 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>
2013-07-16 09:15:06 -04:00

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#
# QAPI command marshaller generator
#
# Copyright IBM, Corp. 2011
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Michael Roth <mdroth@linux.vnet.ibm.com>
#
# This work is licensed under the terms of the GNU GPLv2.
# See the COPYING.LIB file in the top-level directory.
from ordereddict import OrderedDict
from qapi import *
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_decl_enum(name, members, genlist=True):
return mcgen('''
void %(visitor)s(Visitor *m, %(name)s * obj, const char *name, Error **errp);
''',
visitor=type_visitor(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_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)serrp);
''',
name=c_fun(name), args=arglist, retval=retval).rstrip()
if ret_type:
ret += "\n" + mcgen(''''
if (!error_is_set(errp)) {
%(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, errp);" % c_fun(name)
def gen_visitor_output_containers_decl(ret_type):
ret = ""
push_indent()
if ret_type:
ret += mcgen('''
QmpOutputVisitor *mo;
QapiDeallocVisitor *md;
Visitor *v;
''')
pop_indent()
return ret
def gen_visitor_input_containers_decl(args):
ret = ""
push_indent()
if len(args) > 0:
ret += mcgen('''
QmpInputVisitor *mi;
QapiDeallocVisitor *md;
Visitor *v;
''')
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;
''',
argname=c_var(argname), argtype=c_type(argtype))
pop_indent()
return ret.rstrip()
def gen_visitor_input_block(args, obj, dealloc=False):
ret = ""
errparg = 'errp'
if len(args) == 0:
return ret
push_indent()
if dealloc:
errparg = 'NULL'
ret += mcgen('''
md = qapi_dealloc_visitor_new();
v = qapi_dealloc_get_visitor(md);
''')
else:
ret += mcgen('''
mi = qmp_input_visitor_new_strict(%(obj)s);
v = qmp_input_get_visitor(mi);
''',
obj=obj)
for argname, argtype, optional, structured in parse_args(args):
if optional:
ret += mcgen('''
visit_start_optional(v, &has_%(c_name)s, "%(name)s", %(errp)s);
if (has_%(c_name)s) {
''',
c_name=c_var(argname), name=argname, errp=errparg)
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)
if optional:
pop_indent()
ret += mcgen('''
}
visit_end_optional(v, %(errp)s);
''', errp=errparg)
if dealloc:
ret += mcgen('''
qapi_dealloc_visitor_cleanup(md);
''')
else:
ret += mcgen('''
qmp_input_visitor_cleanup(mi);
''')
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)
{
QapiDeallocVisitor *md = qapi_dealloc_visitor_new();
QmpOutputVisitor *mo = qmp_output_visitor_new();
Visitor *v;
v = qmp_output_get_visitor(mo);
%(visitor)s(v, &ret_in, "unused", errp);
if (!error_is_set(errp)) {
*ret_out = qmp_output_get_qobject(mo);
}
qmp_output_visitor_cleanup(mo);
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
{
''',
header=hdr)
if middle_mode:
ret += mcgen('''
Error *local_err = NULL;
Error **errp = &local_err;
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),
visitor_input_vars_decl=gen_visitor_input_vars_decl(args),
visitor_input_block=gen_visitor_input_block(args, "QOBJECT(args)"))
else:
ret += mcgen('''
(void)args;
''')
ret += mcgen('''
if (error_is_set(errp)) {
goto out;
}
%(sync_call)s
''',
sync_call=gen_sync_call(name, args, ret_type, indent=4))
ret += mcgen('''
out:
''')
ret += mcgen('''
%(visitor_input_block_cleanup)s
''',
visitor_input_block_cleanup=gen_visitor_input_block(args, None,
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:o:m",
["source", "header", "prefix=",
"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 ("-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(sys.stdin)
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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