def __init__(self, spec, task_name, kernel_path):
self.old_kernel_dir = os.path.join(kernel_path, spec["old_kernel"])
self.new_kernel_dir = os.path.join(kernel_path, spec["new_kernel"])
self.name = task_name
self.task_dir = os.path.join(tasks_path, task_name)
if "pattern_config" in spec:
self.pattern_config = PatternConfig.create_from_file(
path=os.path.join(patterns_path, spec["pattern_config"]),
patterns_path=base_path)
else:
self.pattern_config = None
if "control_flow_only" in spec:
self.control_flow_only = spec["control_flow_only"]
else:
self.control_flow_only = False
# Create LLVM sources and configuration
self.old_kernel = KernelSourceTree(self.old_kernel_dir,
KernelLlvmSourceBuilder)
self.new_kernel = KernelSourceTree(self.new_kernel_dir,
KernelLlvmSourceBuilder)
self.old_snapshot = Snapshot(self.old_kernel, self.old_kernel)
self.new_snapshot = Snapshot(self.new_kernel, self.new_kernel)
self.config = Config(self.old_snapshot, self.new_snapshot, False,
False, self.pattern_config,
self.control_flow_only, False, False, False, None)
self.functions = dict()
def test_load_snapshot_from_dir_functions():
"""
Create a temporary snapshot directory and try to parse it. Use a YAML
configuration file that contains only a list of functions. Expect that
the function list inside the parsed snapshot contains a single "None"
group which contains the list of loaded functions. All parsed LLVM paths
should contain the list root dir.
"""
with TemporaryDirectory(prefix="test_snapshots_") as snap_dir, \
NamedTemporaryFile(mode="w+t", prefix="snapshot_", suffix=".yaml",
dir=snap_dir) as config_file:
# Populate the temporary snapshot configuration file.
config_file.writelines("""
- created_time: 2020-01-01 00:00:00.000001+00:00
diffkemp_version: '0.1'
kind: function_list
list:
- glob_var: null
llvm: net/core/skbuff.ll
name: ___pskb_trim
tag: null
- glob_var: null
llvm: mm/page_alloc.ll
name: __alloc_pages_nodemask
tag: null
llvm_source_finder:
kind: kernel_with_builder
path: null
source_dir: /diffkemp/kernel/linux-3.10.0-957.el7
llvm_version: 13
""")
# Load the temporary snapshot configuration file.
config_file.seek(0)
config_filename = os.path.basename(config_file.name)
snap = Snapshot.load_from_dir(snap_dir, config_filename)
assert str(snap.created_time) == "2020-01-01 00:00:00.000001+00:00"
assert isinstance(snap.snapshot_tree, SourceTree)
assert isinstance(snap.snapshot_tree.source_finder,
KernelLlvmSourceBuilder)
assert snap.snapshot_tree.source_dir == snap_dir
assert len(snap.fun_groups) == 1
assert None in snap.fun_groups
assert len(snap.fun_groups[None].functions) == 2
assert set(snap.fun_groups[None].functions.keys()) == \
{"___pskb_trim",
"__alloc_pages_nodemask"}
for name, f in snap.fun_groups[None].functions.items():
assert f.glob_var is None
assert f.tag is None
if name == "___pskb_trim":
assert os.path.abspath(f.mod.llvm) == snap_dir + \
"/net/core/skbuff.ll"
elif name == "__alloc_pages_nodemask":
assert os.path.abspath(f.mod.llvm) == snap_dir + \
"/mm/page_alloc.ll"
def test_create_snapshot_from_source():
"""Create a new kernel directory snapshot."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, None, False)
assert snap.kernel_source is not None
assert kernel_dir in snap.kernel_source.kernel_dir
assert snap.snapshot_source is not None
assert output_dir in snap.snapshot_source.kernel_dir
assert snap.fun_kind is None
assert len(snap.fun_groups) == 1
assert len(snap.fun_groups[None].functions) == 0
snap = Snapshot.create_from_source(kernel_dir, output_dir, "sysctl", False)
assert snap.fun_kind == "sysctl"
assert len(snap.fun_groups) == 0
def test_load_snapshot_from_dir_sysctls():
"""
Create a temporary snapshot directory and try to parse it. Use a YAML
configuration file that contains a list of sysctl groups, each group
containing a single function. All parsed LLVM paths should contain the list
root dir.
"""
with TemporaryDirectory(prefix="test_snapshots_sysctl_") as snap_dir, \
NamedTemporaryFile(mode="w+t", prefix="snapshot_", suffix=".yaml",
dir=snap_dir) as config_file:
# Populate the temporary sysctl snapshot configuration file.
config_file.writelines("""
- created_time: 2020-01-01 00:00:00.000001
diffkemp_version: '0.1'
kind: function_list
list:
- functions:
- glob_var: null
llvm: kernel/sched/fair.ll
name: sched_proc_update_handler
tag: proc handler
sysctl: kernel.sched_latency_ns
- functions:
- glob_var: null
llvm: kernel/sysctl.ll
name: proc_dointvec_minmax
tag: proc handler
sysctl: kernel.timer_migration
source_kernel_dir: /diffkemp/kernel/linux-3.10.0-957.el7
""")
# Load the temporary sysctl snapshot configuration file.
config_file.seek(0)
config_filename = os.path.basename(config_file.name)
snap = Snapshot.load_from_dir(snap_dir, config_filename)
assert str(snap.created_time) == "2020-01-01 00:00:00.000001"
assert len(snap.fun_groups) == 2
assert set(snap.fun_groups.keys()) == {
"kernel.sched_latency_ns", "kernel.timer_migration"
}
for name, g in snap.fun_groups.items():
f = None
assert len(g.functions) == 1
if name == "kernel.sched_latency_ns":
assert g.functions.keys() == {"sched_proc_update_handler"}
f = g.functions["sched_proc_update_handler"]
assert os.path.abspath(f.mod.llvm) == snap_dir + \
"/kernel/sched/fair.ll"
elif name == "kernel.timer_migration":
assert g.functions.keys() == {"proc_dointvec_minmax"}
f = g.functions["proc_dointvec_minmax"]
assert os.path.abspath(f.mod.llvm) == snap_dir + \
"/kernel/sysctl.ll"
assert f.tag == "proc handler"
assert f.glob_var is None
def __init__(self, spec, task_name, tasks_path, kernel_path):
self.old_kernel_dir = os.path.join(kernel_path, spec["old_kernel"])
self.new_kernel_dir = os.path.join(kernel_path, spec["new_kernel"])
self.name = task_name
self.task_dir = os.path.join(tasks_path, task_name)
if "control_flow_only" in spec:
self.control_flow_only = spec["control_flow_only"]
else:
self.control_flow_only = False
# Create LLVM sources and configuration
self.old_kernel = KernelSource(self.old_kernel_dir, True)
self.new_kernel = KernelSource(self.new_kernel_dir, True)
self.old_snapshot = Snapshot(self.old_kernel, self.old_kernel)
self.new_snapshot = Snapshot(self.new_kernel, self.new_kernel)
self.config = Config(self.old_snapshot, self.new_snapshot, False,
self.control_flow_only, False, False, None)
self.functions = dict()
def test_to_yaml_sysctls():
"""
Dump a snapshot with multiple sysctl groups into YAML.
YAML string should contain the version of Diffkemp, source kernel
directory, a simple list of function groups, each one containing a
function list with the "name", "llvm", "glob_var" and "tag" fields set,
and the kind of this list, which should be a group list.
The LLVM paths in the YAML should be relative to the snapshot directory.
"""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots-sysctl/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir,
KernelLlvmSourceBuilder, None, "sysctl",
False)
snap.add_fun_group("kernel.sched_latency_ns")
snap.add_fun_group("kernel.timer_migration")
snap.add_fun(
"sched_proc_update_handler",
LlvmModule("snapshots-sysctl/linux-3.10.0-957.el7/"
"kernel/sched/fair.ll"), None, "proc handler",
"kernel.sched_latency_ns")
snap.add_fun(
"proc_dointvec_minmax",
LlvmModule("snapshots-sysctl/linux-3.10.0-957.el7/kernel/sysctl.ll"),
None, "proc handler", "kernel.timer_migration")
yaml_str = snap.to_yaml()
yaml_snap = yaml.safe_load(yaml_str)
assert len(yaml_snap) == 1
yaml_dict = yaml_snap[0]
assert len(yaml_dict) == 7
assert yaml_dict["llvm_source_finder"]["kind"] == "kernel_with_builder"
assert isinstance(yaml_dict["created_time"], datetime.datetime)
assert len(yaml_dict["list"]) == 2
assert set([g["sysctl"] for g in yaml_dict["list"]
]) == {"kernel.sched_latency_ns", "kernel.timer_migration"}
for g in yaml_dict["list"]:
assert len(g["functions"]) == 1
if g["sysctl"] == "kernel.sched_latency_ns":
assert g["functions"][0] == {
"name": "sched_proc_update_handler",
"llvm": "kernel/sched/fair.ll",
"glob_var": None,
"tag": "proc handler"
}
elif g["sysctl"] == "kernel.timer_migration":
assert g["functions"][0] == {
"name": "proc_dointvec_minmax",
"llvm": "kernel/sysctl.ll",
"glob_var": None,
"tag": "proc handler"
}
def test_add_sysctl_fun_group():
"""Create a snapshot and check the creation of a sysctl function group."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, "sysctl", False)
snap.add_fun_group("kernel.sched_latency_ns")
assert len(snap.fun_groups) == 1
assert "kernel.sched_latency_ns" in snap.fun_groups
def test_filter():
"""Filter snapshot functions."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, None, False)
snap.add_fun("___pskb_trim", LlvmKernelModule("net/core/skbuff.ll"))
snap.add_fun("__alloc_pages_nodemask",
LlvmKernelModule("mm/page_alloc.ll"))
snap.filter(["__alloc_pages_nodemask"])
assert len(snap.fun_groups[None].functions) == 1
assert "___pskb_trim" not in snap.fun_groups[None].functions
assert "__alloc_pages_nodemask" in snap.fun_groups[None].functions
def test_add_fun_none_group():
"""Create a snapshot and try to add functions into a None group."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, None, False)
mod = LlvmKernelModule("net/core/skbuff.ll")
snap.add_fun("___pskb_trim", mod)
assert "___pskb_trim" in snap.fun_groups[None].functions
fun_desc = snap.fun_groups[None].functions["___pskb_trim"]
assert fun_desc.mod is mod
assert fun_desc.glob_var is None
assert fun_desc.tag is None
def test_get_by_name_functions():
"""Get the module of inserted function by its name."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, None, False)
mod_buff = LlvmKernelModule("net/core/skbuff.ll")
mod_alloc = LlvmKernelModule("mm/page_alloc.ll")
snap.add_fun("___pskb_trim", mod_buff)
snap.add_fun("__alloc_pages_nodemask", mod_alloc)
fun = snap.get_by_name("___pskb_trim")
assert fun.mod is mod_buff
fun = snap.get_by_name("__alloc_pages_nodemask")
assert fun.mod is mod_alloc
def test_add_fun_sysctl_group():
"""Create a snapshot and try to add functions into sysctl groups."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, "sysctl", False)
snap.add_fun_group("kernel.sched_latency_ns")
mod = LlvmKernelModule("kernel/sched/debug.ll")
snap.add_fun("sched_debug_header", mod, "sysctl_sched_latency",
"using_data_variable \"sysctl_sched_latency\"",
"kernel.sched_latency_ns")
assert "sched_debug_header" in snap.fun_groups[
"kernel.sched_latency_ns"].functions
fun_desc = snap.fun_groups["kernel.sched_latency_ns"].functions[
"sched_debug_header"]
assert fun_desc.mod is mod
assert fun_desc.glob_var == "sysctl_sched_latency"
assert fun_desc.tag == "using_data_variable \"sysctl_sched_latency\""
def test_to_yaml_functions():
"""
Dump a snapshot with a single "None" group into YAML.
YAML string should contain the version of Diffkemp, source kernel
directory, a simple list of functions, each one having the "name",
"llvm", "glob_var" and "tag" fields set, and the kind of this list,
which should be a function list.
The LLVM paths in the YAML should be relative to the snapshot directory.
"""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir,
KernelLlvmSourceBuilder, None, None,
False)
snap.add_fun(
"___pskb_trim",
LlvmModule("snapshots/linux-3.10.0-957.el7/net/core/skbuff.ll"))
snap.add_fun("__alloc_pages_nodemask",
LlvmModule("snapshots/linux-3.10.0-957.el7/mm/page_alloc.ll"))
yaml_str = snap.to_yaml()
yaml_snap = yaml.safe_load(yaml_str)
assert len(yaml_snap) == 1
yaml_dict = yaml_snap[0]
assert len(yaml_dict) == 7
assert isinstance(yaml_dict["created_time"], datetime.datetime)
assert yaml_dict["llvm_source_finder"]["kind"] == "kernel_with_builder"
assert len(yaml_dict["list"]) == 2
assert set([f["name"] for f in yaml_dict["list"]]) ==\
{"___pskb_trim",
"__alloc_pages_nodemask"}
for f in yaml_dict["list"]:
if f["name"] == "___pskb_trim":
assert f["llvm"] == "net/core/skbuff.ll"
elif f["name"] == "__alloc_pages_nodemask":
assert f["llvm"] == "mm/page_alloc.ll"
def test_get_by_name_sysctls():
"""Get the module of inserted function by its name and sysctl group."""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, "sysctl", False)
snap.add_fun_group("kernel.sched_latency_ns")
snap.add_fun_group("kernel.timer_migration")
mod_fair = LlvmKernelModule(
"snapshots-sysctl/linux-3.10.0-957.el7/kernel/sched/fair.ll")
mod_sysctl = LlvmKernelModule(
"snapshots-sysctl/linux-3.10.0-957.el7/kernel/sysctl.ll")
snap.add_fun("sched_proc_update_handler", mod_fair, None, "proc handler",
"kernel.sched_latency_ns")
snap.add_fun("proc_dointvec_minmax", mod_sysctl, None, "proc handler",
"kernel.timer_migration")
# Test that the function
fun = snap.get_by_name("proc_dointvec_minmax", "kernel.sched_latency_ns")
assert fun is None
fun = snap.get_by_name("proc_dointvec_minmax", "kernel.timer_migration")
assert fun.mod is mod_sysctl
def test_get_modules():
"""
Test getting all modules in the snapshot function lists.
Check if the snapshot returns a list of all modules of all groups in case
that multiple groups are present.
"""
kernel_dir = "kernel/linux-3.10.0-957.el7"
output_dir = "snapshots/linux-3.10.0-957.el7"
snap = Snapshot.create_from_source(kernel_dir, output_dir, "sysctl", False)
snap.add_fun_group("kernel.sched_latency_ns")
snap.add_fun_group("kernel.timer_migration")
snap.add_fun("sched_proc_update_handler",
LlvmKernelModule("kernel/sched/fair.ll"), None,
"proc_handler", "kernel.sched_latency_ns")
snap.add_fun("proc_dointvec_minmax", LlvmKernelModule("kernel/sysctl.ll"),
None, "proc_handler", "kernel.timer_migration")
modules = snap.modules()
assert len(modules) == 2
assert set([m.llvm for m in modules
]) == {"kernel/sched/fair.ll", "kernel/sysctl.ll"}
def compare(args):
"""
Compare snapshots of linux kernels. Runs the semantic comparison and shows
information about the compared functions that are semantically different.
"""
# Parse both the new and the old snapshot.
old_snapshot = Snapshot.load_from_dir(args.snapshot_dir_old)
new_snapshot = Snapshot.load_from_dir(args.snapshot_dir_new)
# Set the output directory
if not args.stdout:
if args.output_dir:
output_dir = args.output_dir
if os.path.isdir(output_dir):
sys.stderr.write("Error: output directory exists\n")
sys.exit(errno.EEXIST)
else:
output_dir = default_output_dir(args.snapshot_dir_old,
args.snapshot_dir_new)
else:
output_dir = None
if args.function:
old_snapshot.filter([args.function])
new_snapshot.filter([args.function])
config = Config(old_snapshot, new_snapshot, args.show_diff,
args.output_llvm_ir, args.control_flow_only,
args.print_asm_diffs, args.verbose, args.enable_simpll_ffi,
args.semdiff_tool)
result = Result(Result.Kind.NONE,
args.snapshot_dir_old,
args.snapshot_dir_old,
start_time=default_timer())
for group_name, group in sorted(old_snapshot.fun_groups.items()):
group_printed = False
# Set the group directory
if output_dir is not None and group_name is not None:
group_dir = os.path.join(output_dir, group_name)
else:
group_dir = None
result_graph = None
cache = SimpLLCache(mkdtemp())
if args.enable_module_cache:
module_cache = _generate_module_cache(group.functions.items(),
group_name, new_snapshot, 3)
else:
module_cache = None
for fun, old_fun_desc in sorted(group.functions.items()):
# Check if the function exists in the other snapshot
new_fun_desc = new_snapshot.get_by_name(fun, group_name)
if not new_fun_desc:
continue
# Check if the module exists in both snapshots
if old_fun_desc.mod is None or new_fun_desc.mod is None:
result.add_inner(Result(Result.Kind.UNKNOWN, fun, fun))
if group_name is not None and not group_printed:
print("{}:".format(group_name))
group_printed = True
print("{}: unknown".format(fun))
continue
# If function has a global variable, set it
glob_var = KernelParam(old_fun_desc.glob_var) \
if old_fun_desc.glob_var else None
# Run the semantic diff
fun_result = functions_diff(mod_first=old_fun_desc.mod,
mod_second=new_fun_desc.mod,
fun_first=fun,
fun_second=fun,
glob_var=glob_var,
config=config,
prev_result_graph=result_graph,
function_cache=cache,
module_cache=module_cache)
result_graph = fun_result.graph
if fun_result is not None:
if args.regex_filter is not None:
# Filter results by regex
pattern = re.compile(args.regex_filter)
for called_res in fun_result.inner.values():
if pattern.search(called_res.diff):
break
else:
fun_result.kind = Result.Kind.EQUAL_SYNTAX
result.add_inner(fun_result)
# Printing information about failures and non-equal functions.
if fun_result.kind in [
Result.Kind.NOT_EQUAL, Result.Kind.ERROR,
Result.Kind.UNKNOWN
]:
if fun_result.kind == Result.Kind.NOT_EQUAL:
# Create the output directory if needed
if output_dir is not None:
if not os.path.isdir(output_dir):
os.mkdir(output_dir)
# Create the group directory or print the group name
# if needed
if group_dir is not None:
if not os.path.isdir(group_dir):
os.mkdir(group_dir)
elif group_name is not None and not group_printed:
print("{}:".format(group_name))
group_printed = True
print_syntax_diff(
snapshot_dir_old=args.snapshot_dir_old,
snapshot_dir_new=args.snapshot_dir_new,
fun=fun,
fun_result=fun_result,
fun_tag=old_fun_desc.tag,
output_dir=group_dir if group_dir else output_dir,
show_diff=args.show_diff,
initial_indent=2 if (group_name is not None
and group_dir is None) else 0)
else:
# Print the group name if needed
if group_name is not None and not group_printed:
print("{}:".format(group_name))
group_printed = True
print("{}: {}".format(fun, str(fun_result.kind)))
# Clean LLVM modules (allow GC to collect the occupied memory)
old_fun_desc.mod.clean_module()
new_fun_desc.mod.clean_module()
LlvmKernelModule.clean_all()
old_snapshot.finalize()
new_snapshot.finalize()
if output_dir is not None and os.path.isdir(output_dir):
print("Differences stored in {}/".format(output_dir))
if args.report_stat:
print("")
print("Statistics")
print("----------")
result.stop_time = default_timer()
result.report_stat(args.show_errors)
return 0
def generate(args):
"""
Generate snapshot of sources of kernel functions.
This involves:
- find source code with functions definitions
- compile the source codes into LLVM IR
- copy LLVM and C source files into snapshot directory
- create YAML with list mapping functions to their LLVM sources
"""
# Create a new snapshot from the source directory.
snapshot = Snapshot.create_from_source(args.kernel_dir, args.output_dir,
"sysctl" if args.sysctl else None)
source = snapshot.kernel_source
# Build sources for symbols from the list into LLVM IR
with open(args.functions_list, "r") as fun_list_file:
for line in fun_list_file.readlines():
symbol = line.strip()
if not symbol or not (symbol[0].isalpha() or symbol[0] == "_"):
continue
if args.sysctl:
# For a sysctl parameter, we have to:
# - get LLVM of a file which defines the sysctl option
# - find and compile proc handler function and add it to the
# snapshot
# - find sysctl data variable
# - find, complile, and add to snapshot all functions that
# use the data variable
# Get module with sysctl definitions
try:
sysctl_mod = source.get_sysctl_module(symbol)
except SourceNotFoundException:
print("{}: sysctl not supported".format(symbol))
# Iterate all sysctls represented by the symbol (it can be
# a pattern).
sysctl_list = sysctl_mod.parse_sysctls(symbol)
if not sysctl_list:
print("{}: no sysctl found".format(symbol))
for sysctl in sysctl_list:
print("{}:".format(sysctl))
# New group in function list for the sysctl
snapshot.add_fun_group(sysctl)
# Proc handler function for sysctl
proc_fun = sysctl_mod.get_proc_fun(sysctl)
if proc_fun:
try:
proc_fun_mod = source.get_module_for_symbol(
proc_fun)
snapshot.add_fun(name=proc_fun,
llvm_mod=proc_fun_mod,
glob_var=None,
tag="proc handler function",
group=sysctl)
print(" {}: {} (proc handler)".format(
proc_fun,
os.path.relpath(proc_fun_mod.llvm,
args.kernel_dir)))
except SourceNotFoundException:
print(" could not build proc handler")
# Functions using the sysctl data variable
data = sysctl_mod.get_data(sysctl)
if not data:
continue
for data_src in source.find_srcs_using_symbol(data.name):
data_mod = source.get_module_from_source(data_src)
if not data_mod:
continue
for data_fun in \
data_mod.get_functions_using_param(data):
if data_fun == proc_fun:
continue
snapshot.add_fun(name=data_fun,
llvm_mod=data_mod,
glob_var=data.name,
tag="function using sysctl data "
"variable \"{}\"".format(
data.name),
group=sysctl)
print(
" {}: {} (using data variable \"{}\")".format(
data_fun,
os.path.relpath(data_mod.llvm,
args.kernel_dir),
data.name))
else:
try:
# For a normal function, we compile its source and include
# it into the snapshot
sys.stdout.write("{}: ".format(symbol))
llvm_mod = source.get_module_for_symbol(symbol)
if not llvm_mod.has_function(symbol):
print("unsupported")
continue
print(os.path.relpath(llvm_mod.llvm, args.kernel_dir))
snapshot.add_fun(symbol, llvm_mod)
except SourceNotFoundException:
print("source not found")
snapshot.add_fun(symbol, None)
snapshot.generate_snapshot_dir()
snapshot.finalize()