From e53b45cd3207669861b8461474ace91e785acb62 Mon Sep 17 00:00:00 2001
From: Martin Teichmann <martin.teichmann@gmail.com>
Date: Sun, 12 Feb 2023 14:18:02 +0000
Subject: [PATCH] use isinstance with Expression, not int
---
ebpfcat/ebpf.py | 92 ++++++++++++++++++++++++++-----------------------
1 file changed, 48 insertions(+), 44 deletions(-)
diff --git a/ebpfcat/ebpf.py b/ebpfcat/ebpf.py
index bf4c9fd..d0a5d05 100644
--- a/ebpfcat/ebpf.py
+++ b/ebpfcat/ebpf.py
@@ -268,8 +268,7 @@ class AssembleError(Exception):
def comparison(uposop, unegop, sposop, snegop):
def ret(self, value):
- if self.signed or ((value < 0) if isinstance(value, int)
- else value.signed):
+ if self.signed or issigned(value):
return SimpleComparison(self.ebpf, self, value, (sposop, snegop))
else:
return SimpleComparison(self.ebpf, self, value, (uposop, unegop))
@@ -361,7 +360,7 @@ class SimpleComparison(Comparison):
def compare(self, negative):
with self.left.calculate(None, None) as (self.dst, _):
with ExitStack() as exitStack:
- if not isinstance(self.right, int):
+ if isinstance(self.right, Expression):
self.src, _ = exitStack.enter_context(
self.right.calculate(None, None))
self.origin = len(self.ebpf.opcodes)
@@ -374,14 +373,14 @@ class SimpleComparison(Comparison):
if self.opcode == Opcode.JMP:
inst = Instruction(Opcode.JMP, 0, 0,
len(self.ebpf.opcodes) - self.origin - 1, 0)
- elif isinstance(self.right, int):
- inst = Instruction(
- self.opcode, self.dst, 0,
- len(self.ebpf.opcodes) - self.origin - 1, self.right)
- else:
+ elif isinstance(self.right, Expression):
inst = Instruction(
self.opcode + Opcode.REG, self.dst, self.src,
len(self.ebpf.opcodes) - self.origin - 1, 0)
+ else:
+ inst = Instruction(
+ self.opcode, self.dst, 0,
+ len(self.ebpf.opcodes) - self.origin - 1, self.right)
self.ebpf.opcodes[self.origin] = inst
if not retarget:
self.ebpf.owners, self.owners = \
@@ -423,11 +422,17 @@ class InvertComparison(Comparison):
self.value.target(retarget)
+def issigned(value):
+ if isinstance(value, Expression):
+ return value.signed
+ else:
+ return value < 0
+
+
def binary(opcode):
def ret(self, value):
return Binary(self.ebpf, self, value, opcode,
- self.signed or ((value < 0) if isinstance(value, int)
- else value.signed), False)
+ self.signed or issigned(value), False)
return ret
def rbinary(opcode):
@@ -561,22 +566,22 @@ class Binary(Expression):
@contextmanager
def calculate(self, dst, long, force=False):
orig_dst = dst
- if not isinstance(self.right, int) and self.right.contains(dst):
+ if isinstance(self.right, Expression) and self.right.contains(dst):
dst = None
with self.ebpf.get_free_register(dst) as dst:
with self.left.calculate(dst, long, True) as (dst, l_long):
if long is None:
long = l_long
- if isinstance(self.right, int):
- self.ebpf.append(self.operator + Opcode.LONG * long,
- dst, 0, 0, self.right)
- else:
+ if isinstance(self.right, Expression):
with self.right.calculate(None, long) as (src, r_long):
self.ebpf.append(
self.operator + Opcode.REG
+ Opcode.LONG * ((r_long or l_long)
if long is None else long),
dst, src, 0, 0)
+ else:
+ self.ebpf.append(self.operator + Opcode.LONG * long,
+ dst, 0, 0, self.right)
if orig_dst is None or orig_dst == dst:
yield dst, long
return
@@ -584,7 +589,7 @@ class Binary(Expression):
yield orig_dst, long
def contains(self, no):
- return self.left.contains(no) or (not isinstance(self.right, int)
+ return self.left.contains(no) or (isinstance(self.right, Expression)
and self.right.contains(no))
@@ -614,6 +619,7 @@ class Negate(Expression):
def __init__(self, ebpf, arg):
self.ebpf = ebpf
self.arg = arg
+ self.signed = True
@contextmanager
def calculate(self, dst, long, force=False):
@@ -650,18 +656,18 @@ class Sum(Binary):
super().__init__(ebpf, left, right, Opcode.ADD, right < 0, False)
def __add__(self, value):
- if isinstance(value, int):
- return Sum(self.ebpf, self.left, self.right + value)
- else:
+ if isinstance(value, Expression):
return super().__add__(value)
+ else:
+ return Sum(self.ebpf, self.left, self.right + value)
__radd__ = __add__
def __sub__(self, value):
- if isinstance(value, int):
- return Sum(self.ebpf, self.left, self.right - value)
- else:
+ if isinstance(value, Expression):
return super().__sub__(value)
+ else:
+ return Sum(self.ebpf, self.left, self.right - value)
class AndExpression(Binary):
@@ -728,18 +734,18 @@ class Register(Expression):
self.signed = signed
def __add__(self, value):
- if isinstance(value, int) and self.long:
- return Sum(self.ebpf, self, value)
- else:
+ if isinstance(value, Expression) or not self.long:
return super().__add__(value)
+ else:
+ return Sum(self.ebpf, self, value)
__radd__ = __add__
def __sub__(self, value):
- if isinstance(value, int) and self.long:
- return Sum(self.ebpf, self, -value)
- else:
+ if isinstance(value, Expression) or not self.long:
return super().__sub__(value)
+ else:
+ return Sum(self.ebpf, self, -value)
@contextmanager
def calculate(self, dst, long, force=False):
@@ -865,21 +871,21 @@ class MemoryDesc:
mask = ((1 << fmt[1]) - 1) << fmt[0]
value = (mask & (value << self.fmt[0]) | ~mask & before)
opcode = Opcode.STX
- elif isinstance(value, int):
- ebpf.append(Opcode.ST + bits, self.base_register, 0,
- addr, value)
- return
elif isinstance(value, IAdd):
value = value.value
- if isinstance(value, int):
+ if not isinstance(value, Expression):
with ebpf.get_free_register(None) as src:
ebpf.r[src] = value
ebpf.append(Opcode.XADD + bits, self.base_register,
src, addr, 0)
return
opcode = Opcode.XADD
- else:
+ elif isinstance(value, Expression):
opcode = Opcode.STX
+ else:
+ ebpf.append(Opcode.ST + bits, self.base_register, 0,
+ addr, value)
+ return
with value.calculate(None, isinstance(fmt, str) and fmt in 'qQ'
) as (src, _):
ebpf.append(opcode + bits, self.base_register, src, addr, 0)
@@ -922,11 +928,7 @@ class MemoryMap:
else:
dst, _ = exitStack.enter_context(addr.calculate(None, True))
offset = 0
- if isinstance(value, int):
- self.ebpf.append(Opcode.ST + Memory.fmt_to_opcode[self.fmt],
- dst, 0, offset, value)
- return
- elif isinstance(value, IAdd):
+ if isinstance(value, IAdd):
value = value.value
if isinstance(value, int):
with self.ebpf.get_free_register(None) as src:
@@ -936,8 +938,12 @@ class MemoryMap:
dst, src, offset, 0)
return
opcode = Opcode.XADD
- else:
+ elif isinstance(value, Expression):
opcode = Opcode.STX
+ else:
+ self.ebpf.append(Opcode.ST + Memory.fmt_to_opcode[self.fmt],
+ dst, 0, offset, value)
+ return
with value.calculate(None, None) as (src, _):
self.ebpf.append(opcode + Memory.fmt_to_opcode[self.fmt],
dst, src, offset, 0)
@@ -1025,13 +1031,11 @@ class RegisterArray:
def __setitem__(self, no, value):
self.ebpf.owners.add(no)
- if isinstance(value, int):
- self.ebpf._load_value(no, value)
- elif isinstance(value, Expression):
+ if isinstance(value, Expression):
with value.calculate(no, self.long, True):
pass
else:
- raise AssembleError("cannot compile")
+ self.ebpf._load_value(no, value)
def __getitem__(self, no):
return Register(no, self.ebpf, self.long, self.signed)
--
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