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#! /usr/bin/env python3
"""Generate coroutine wrappers for block subsystem.
The program parses one or several concatenated c files from stdin,
searches for functions with the 'co_wrapper' specifier
and generates corresponding wrappers on stdout.
Usage: block-coroutine-wrapper.py generated-file.c FILE.[ch]...
Copyright (c) 2020 Virtuozzo International GmbH.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
"""
import sys
import re
from typing import Iterator
def gen_header():
copyright = re.sub('^.*Copyright', 'Copyright', __doc__, flags=re.DOTALL)
copyright = re.sub('^(?=.)', ' * ', copyright.strip(), flags=re.MULTILINE)
copyright = re.sub('^$', ' *', copyright, flags=re.MULTILINE)
return f"""\
/*
* File is generated by scripts/block-coroutine-wrapper.py
*
{copyright}
*/
#include "qemu/osdep.h"
#include "block/coroutines.h"
#include "block/block-gen.h"
#include "block/block_int.h"\
"""
class ParamDecl:
param_re = re.compile(r'(?P<decl>'
r'(?P<type>.*[ *])'
r'(?P<name>[a-z][a-z0-9_]*)'
r')')
def __init__(self, param_decl: str) -> None:
m = self.param_re.match(param_decl.strip())
if m is None:
raise ValueError(f'Wrong parameter declaration: "{param_decl}"')
self.decl = m.group('decl')
self.type = m.group('type')
self.name = m.group('name')
class FuncDecl:
def __init__(self, return_type: str, name: str, args: str,
variant: str) -> None:
self.return_type = return_type.strip()
self.name = name.strip()
self.struct_name = snake_to_camel(self.name)
self.args = [ParamDecl(arg.strip()) for arg in args.split(',')]
self.create_only_co = 'mixed' not in variant
subsystem, subname = self.name.split('_', 1)
self.co_name = f'{subsystem}_co_{subname}'
t = self.args[0].type
if t == 'BlockDriverState *':
ctx = 'bdrv_get_aio_context(bs)'
elif t == 'BdrvChild *':
ctx = 'bdrv_get_aio_context(child->bs)'
elif t == 'BlockBackend *':
ctx = 'blk_get_aio_context(blk)'
else:
ctx = 'qemu_get_aio_context()'
self.ctx = ctx
def gen_list(self, format: str) -> str:
return ', '.join(format.format_map(arg.__dict__) for arg in self.args)
def gen_block(self, format: str) -> str:
return '\n'.join(format.format_map(arg.__dict__) for arg in self.args)
# Match wrappers declared with a co_wrapper mark
func_decl_re = re.compile(r'^int\s*co_wrapper'
r'(?P<variant>(_[a-z][a-z0-9_]*)?)\s*'
r'(?P<wrapper_name>[a-z][a-z0-9_]*)'
r'\((?P<args>[^)]*)\);$', re.MULTILINE)
def func_decl_iter(text: str) -> Iterator:
for m in func_decl_re.finditer(text):
yield FuncDecl(return_type='int',
name=m.group('wrapper_name'),
args=m.group('args'),
variant=m.group('variant'))
def snake_to_camel(func_name: str) -> str:
"""
Convert underscore names like 'some_function_name' to camel-case like
'SomeFunctionName'
"""
words = func_name.split('_')
words = [w[0].upper() + w[1:] for w in words]
return ''.join(words)
def create_mixed_wrapper(func: FuncDecl) -> str:
"""
Checks if we are already in coroutine
"""
name = func.co_name
struct_name = func.struct_name
return f"""\
int {func.name}({ func.gen_list('{decl}') })
{{
if (qemu_in_coroutine()) {{
return {name}({ func.gen_list('{name}') });
}} else {{
{struct_name} s = {{
.poll_state.ctx = {func.ctx},
.poll_state.in_progress = true,
{ func.gen_block(' .{name} = {name},') }
}};
s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
return bdrv_poll_co(&s.poll_state);
}}
}}"""
def create_co_wrapper(func: FuncDecl) -> str:
"""
Assumes we are not in coroutine, and creates one
"""
name = func.co_name
struct_name = func.struct_name
return f"""\
int {func.name}({ func.gen_list('{decl}') })
{{
{struct_name} s = {{
.poll_state.ctx = {func.ctx},
.poll_state.in_progress = true,
{ func.gen_block(' .{name} = {name},') }
}};
assert(!qemu_in_coroutine());
s.poll_state.co = qemu_coroutine_create({name}_entry, &s);
return bdrv_poll_co(&s.poll_state);
}}"""
def gen_wrapper(func: FuncDecl) -> str:
assert not '_co_' in func.name
assert func.return_type == 'int'
name = func.co_name
struct_name = func.struct_name
creation_function = create_mixed_wrapper
if func.create_only_co:
creation_function = create_co_wrapper
return f"""\
/*
* Wrappers for {name}
*/
typedef struct {struct_name} {{
BdrvPollCo poll_state;
{ func.gen_block(' {decl};') }
}} {struct_name};
static void coroutine_fn {name}_entry(void *opaque)
{{
{struct_name} *s = opaque;
s->poll_state.ret = {name}({ func.gen_list('s->{name}') });
s->poll_state.in_progress = false;
aio_wait_kick();
}}
{creation_function(func)}"""
def gen_wrappers(input_code: str) -> str:
res = ''
for func in func_decl_iter(input_code):
res += '\n\n\n'
res += gen_wrapper(func)
return res
if __name__ == '__main__':
if len(sys.argv) < 3:
exit(f'Usage: {sys.argv[0]} OUT_FILE.c IN_FILE.[ch]...')
with open(sys.argv[1], 'w', encoding='utf-8') as f_out:
f_out.write(gen_header())
for fname in sys.argv[2:]:
with open(fname, encoding='utf-8') as f_in:
f_out.write(gen_wrappers(f_in.read()))
f_out.write('\n')
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