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 ordereddict import OrderedDict
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 generate_command_decl(name, args, ret_type):
arglist=""
for argname, argtype, optional in parse_args(args):
argtype = c_type(argtype, is_param=True)
if optional:
arglist += "bool has_%s, " % c_name(argname)
arglist += "%s %s, " % (argtype, c_name(argname))
return mcgen('''
%(ret_type)s qmp_%(name)s(%(args)sError **errp);
''',
ret_type=c_type(ret_type), name=c_name(name),
args=arglist)
def gen_err_check(err):
if not err:
return ''
return mcgen('''
if (%(err)s) {
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;
}
''',
err=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
def gen_sync_call(name, args, ret_type):
ret = ""
arglist=""
retval=""
if ret_type:
retval = "retval = "
for argname, argtype, optional in parse_args(args):
if optional:
arglist += "has_%s, " % c_name(argname)
arglist += "%s, " % (c_name(argname))
push_indent()
ret = mcgen('''
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
%(retval)sqmp_%(name)s(%(args)s&local_err);
''',
name=c_name(name), args=arglist, retval=retval)
if ret_type:
ret += gen_err_check('local_err')
ret += mcgen('''
qmp_marshal_output_%(c_name)s(retval, ret, &local_err);
''',
c_name=c_name(name))
pop_indent()
return ret
def gen_visitor_input_containers_decl(args):
ret = ""
push_indent()
if len(args) > 0:
ret += mcgen('''
QmpInputVisitor *mi = qmp_input_visitor_new_strict(QOBJECT(args));
QapiDeallocVisitor *md;
Visitor *v;
''')
pop_indent()
return ret
def gen_visitor_input_vars_decl(args):
ret = ""
push_indent()
for argname, argtype, optional in parse_args(args):
if optional:
ret += mcgen('''
bool has_%(argname)s = false;
''',
argname=c_name(argname))
if is_c_ptr(argtype):
ret += mcgen('''
%(argtype)s %(argname)s = NULL;
''',
argname=c_name(argname), argtype=c_type(argtype))
else:
ret += mcgen('''
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>
2014-05-20 19:20:39 +02:00
%(argtype)s %(argname)s = {0};
''',
argname=c_name(argname), argtype=c_type(argtype))
pop_indent()
return ret
def gen_visitor_input_block(args, dealloc=False):
ret = ""
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
errparg = '&local_err'
errarg = 'local_err'
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 len(args) == 0:
return ret
push_indent()
if dealloc:
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
errparg = 'NULL'
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
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 in parse_args(args):
if optional:
ret += mcgen('''
visit_optional(v, &has_%(c_name)s, "%(name)s", %(errp)s);
''',
c_name=c_name(argname), name=argname, errp=errparg)
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 += gen_err_check(errarg)
ret += mcgen('''
if (has_%(c_name)s) {
''',
c_name=c_name(argname))
push_indent()
ret += mcgen('''
visit_type_%(visitor)s(v, &%(c_name)s, "%(name)s", %(errp)s);
''',
c_name=c_name(argname), name=argname, argtype=argtype,
visitor=type_name(argtype), errp=errparg)
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 += gen_err_check(errarg)
if optional:
pop_indent()
ret += mcgen('''
}
''')
if dealloc:
ret += mcgen('''
qapi_dealloc_visitor_cleanup(md);
''')
pop_indent()
return ret
def gen_marshal_output(name, ret_type):
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)
{
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
Error *local_err = NULL;
QmpOutputVisitor *mo = qmp_output_visitor_new();
QapiDeallocVisitor *md;
Visitor *v;
v = qmp_output_get_visitor(mo);
visit_type_%(visitor)s(v, &ret_in, "unused", &local_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
if (local_err) {
goto out;
}
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_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);
visit_type_%(visitor)s(v, &ret_in, "unused", NULL);
qapi_dealloc_visitor_cleanup(md);
}
''',
c_ret_type=c_type(ret_type), c_name=c_name(name),
visitor=type_name(ret_type))
return ret
def gen_marshal_input_decl(name, middle_mode):
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
ret = 'void qmp_marshal_input_%s(QDict *args, QObject **ret, Error **errp)' % c_name(name)
if not middle_mode:
ret = "static " + ret
return ret
def gen_marshal_input(name, args, ret_type, middle_mode):
hdr = gen_marshal_input_decl(name, middle_mode)
ret = mcgen('''
%(header)s
{
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
Error *local_err = NULL;
''',
header=hdr)
if ret_type:
ret += mcgen('''
%(c_type)s retval;
''',
c_type=c_type(ret_type))
if len(args) > 0:
ret += gen_visitor_input_containers_decl(args)
ret += gen_visitor_input_vars_decl(args) + '\n'
ret += gen_visitor_input_block(args) + '\n'
else:
ret += mcgen('''
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
(void)args;
''')
ret += gen_sync_call(name, args, 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
if re.search('^ *goto out\\;', ret, re.MULTILINE):
ret += mcgen('''
out:
''')
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
error_propagate(errp, local_err);
''')
ret += gen_visitor_input_block(args, 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_registry(commands):
registry=""
push_indent()
for cmd in commands:
options = 'QCO_NO_OPTIONS'
if not cmd.get('success-response', True):
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_name(cmd['command']),
opts=options)
pop_indent()
ret = mcgen('''
static void qmp_init_marshal(void)
{
''')
ret += registry
ret += mcgen('''
}
qapi_init(qmp_init_marshal);
''')
return ret
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
exprs = parse_schema(input_file)
commands = filter(lambda expr: expr.has_key('command'), exprs)
commands = filter(lambda expr: not expr.has_key('gen'), commands)
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))
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)
fdecl.write(ret)
if ret_type:
ret = gen_marshal_output(cmd['command'], ret_type) + "\n"
fdef.write(ret)
if middle_mode:
fdecl.write('%s;\n' % gen_marshal_input_decl(cmd['command'], middle_mode))
ret = gen_marshal_input(cmd['command'], arglist, ret_type, middle_mode) + "\n"
fdef.write(ret)
if not middle_mode:
ret = gen_registry(commands)
fdef.write(ret)
close_output(fdef, fdecl)