/usr/src/openvswitch-1.4.0/build-aux/check-structs is in openvswitch-datapath-dkms 1.4.0-1ubuntu1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
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import os.path
import sys
import re
macros = {}
anyWarnings = False
types = {}
types['char'] = {"size": 1, "alignment": 1}
types['uint8_t'] = {"size": 1, "alignment": 1}
types['uint16_t'] = {"size": 2, "alignment": 2}
types['uint32_t'] = {"size": 4, "alignment": 4}
types['uint64_t'] = {"size": 8, "alignment": 8}
types['ovs_be16'] = {"size": 2, "alignment": 2}
types['ovs_be32'] = {"size": 4, "alignment": 4}
types['ovs_be64'] = {"size": 8, "alignment": 8}
types['ovs_32aligned_be64'] = {"size": 8, "alignment": 4}
token = None
line = ""
idRe = "[a-zA-Z_][a-zA-Z_0-9]*"
tokenRe = "#?" + idRe + "|[0-9]+|."
inComment = False
inDirective = False
def getToken():
global token
global line
global inComment
global inDirective
while True:
line = line.lstrip()
if line != "":
if line.startswith("/*"):
inComment = True
line = line[2:]
elif inComment:
commentEnd = line.find("*/")
if commentEnd < 0:
line = ""
else:
inComment = False
line = line[commentEnd + 2:]
else:
match = re.match(tokenRe, line)
token = match.group(0)
line = line[len(token):]
if token.startswith('#'):
inDirective = True
elif token in macros and not inDirective:
line = macros[token] + line
continue
return True
elif inDirective:
token = "$"
inDirective = False
return True
else:
global lineNumber
line = inputFile.readline()
lineNumber += 1
while line.endswith("\\\n"):
line = line[:-2] + inputFile.readline()
lineNumber += 1
if line == "":
if token == None:
fatal("unexpected end of input")
token = None
return False
def fatal(msg):
sys.stderr.write("%s:%d: error at \"%s\": %s\n" % (fileName, lineNumber, token, msg))
sys.exit(1)
def warn(msg):
global anyWarnings
anyWarnings = True
sys.stderr.write("%s:%d: warning: %s\n" % (fileName, lineNumber, msg))
def skipDirective():
getToken()
while token != '$':
getToken()
def isId(s):
return re.match(idRe + "$", s) != None
def forceId():
if not isId(token):
fatal("identifier expected")
def forceInteger():
if not re.match('[0-9]+$', token):
fatal("integer expected")
def match(t):
if token == t:
getToken()
return True
else:
return False
def forceMatch(t):
if not match(t):
fatal("%s expected" % t)
def parseTaggedName():
assert token in ('struct', 'union')
name = token
getToken()
forceId()
name = "%s %s" % (name, token)
getToken()
return name
def parseTypeName():
if token in ('struct', 'union'):
name = parseTaggedName()
elif isId(token):
name = token
getToken()
else:
fatal("type name expected")
if name in types:
return name
else:
fatal("unknown type \"%s\"" % name)
def parseStruct():
isStruct = token == 'struct'
structName = parseTaggedName()
if token == ";":
return
ofs = size = 0
alignment = 4 # ARM has minimum 32-bit alignment
forceMatch('{')
while not match('}'):
typeName = parseTypeName()
typeSize = types[typeName]['size']
typeAlignment = types[typeName]['alignment']
forceId()
memberName = token
getToken()
if match('['):
if token == ']':
count = 0
else:
forceInteger()
count = int(token)
getToken()
forceMatch(']')
else:
count = 1
nBytes = typeSize * count
if isStruct:
if ofs % typeAlignment:
shortage = typeAlignment - (ofs % typeAlignment)
warn("%s member %s is %d bytes short of %d-byte alignment"
% (structName, memberName, shortage, typeAlignment))
size += shortage
ofs += shortage
size += nBytes
ofs += nBytes
else:
if nBytes > size:
size = nBytes
if typeAlignment > alignment:
alignment = typeAlignment
forceMatch(';')
if size % alignment:
shortage = alignment - (size % alignment)
if (structName == "struct ofp_packet_in" and
shortage == 2 and
memberName == 'data' and
count == 0):
# This is intentional
pass
else:
warn("%s needs %d bytes of tail padding" % (structName, shortage))
size += shortage
types[structName] = {"size": size, "alignment": alignment}
return structName
def checkStructs():
if len(sys.argv) < 2:
sys.stderr.write("at least one non-option argument required; "
"use --help for help")
sys.exit(1)
if '--help' in sys.argv:
argv0 = os.path.basename(sys.argv[0])
print '''\
%(argv0)s, for checking struct and struct member alignment
usage: %(argv0)s HEADER [HEADER]...
This program reads the header files specified on the command line and
verifies that all struct members are aligned on natural boundaries
without any need for the compiler to add additional padding. It also
verifies that each struct's size is a multiple of 32 bits (because
some ABIs for ARM require all structs to be a multiple of 32 bits), or
64 bits if the struct has any 64-bit members, again without the
compiler adding additional padding. Finally, it checks struct size
assertions using OFP_ASSERT.
Header files are read in the order specified. #include directives are
not processed, so specify them in dependency order.
This program is specialized for reading include/openflow/openflow.h
and include/openflow/nicira-ext.h. It will not work on arbitrary
header files without extensions.''' % {"argv0": argv0}
sys.exit(0)
global fileName
for fileName in sys.argv[1:]:
global inputFile
global lineNumber
inputFile = open(fileName)
lineNumber = 0
lastStruct = None
while getToken():
if token in ("#ifdef", "#ifndef", "#include",
"#endif", "#elif", "#else"):
skipDirective()
elif token == "#define":
getToken()
name = token
if line.startswith('('):
skipDirective()
else:
definition = ""
getToken()
while token != '$':
definition += token
getToken()
macros[name] = definition
elif token == "enum":
while token != ';':
getToken()
elif token in ('struct', 'union'):
lastStruct = parseStruct()
elif match('OFP_ASSERT') or match('BOOST_STATIC_ASSERT'):
forceMatch('(')
forceMatch('sizeof')
forceMatch('(')
typeName = parseTypeName()
if typeName != lastStruct:
warn("checking size of %s but %s was most recently defined"
% (typeName, lastStruct))
forceMatch(')')
forceMatch('=')
forceMatch('=')
forceInteger()
size = int(token)
getToken()
forceMatch(')')
if types[typeName]['size'] != size:
warn("%s is %d bytes long but declared as %d" % (
typeName, types[typeName]['size'], size))
else:
fatal("parse error")
inputFile.close()
if anyWarnings:
sys.exit(1)
if __name__ == '__main__':
checkStructs()
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