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https://github.com/varun-r-mallya/Python-BPF.git
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71 lines
2.4 KiB
Python
71 lines
2.4 KiB
Python
"""
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LICENSE global variable processing for BPF programs.
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This module handles the processing of the LICENSE function which is required
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for BPF programs to declare their license (typically "GPL").
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"""
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from llvmlite import ir
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import ast
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from logging import Logger
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import logging
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logger: Logger = logging.getLogger(__name__)
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def emit_license(module: ir.Module, license_str: str):
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"""
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Emit a LICENSE global variable into the LLVM IR module.
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Args:
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module: The LLVM IR module to add the LICENSE variable to
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license_str: The license string (e.g., 'GPL')
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Returns:
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The created global variable
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"""
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license_bytes = license_str.encode("utf8") + b"\x00"
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elems = [ir.Constant(ir.IntType(8), b) for b in license_bytes]
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ty = ir.ArrayType(ir.IntType(8), len(elems))
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gvar = ir.GlobalVariable(module, ty, name="LICENSE")
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gvar.initializer = ir.Constant(ty, elems) # type: ignore
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gvar.align = 1 # type: ignore
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gvar.linkage = "dso_local" # type: ignore
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gvar.global_constant = False
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gvar.section = "license" # type: ignore
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return gvar
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def license_processing(tree, module):
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"""Process the LICENSE function decorated with @bpf and @bpfglobal and return the section name"""
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count = 0
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for node in tree.body:
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if isinstance(node, ast.FunctionDef) and node.name == "LICENSE":
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# check decorators
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decorators = [
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dec.id for dec in node.decorator_list if isinstance(dec, ast.Name)
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]
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if "bpf" in decorators and "bpfglobal" in decorators:
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if count == 0:
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count += 1
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# check function body has a return string
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if (
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len(node.body) == 1
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and isinstance(node.body[0], ast.Return)
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and isinstance(node.body[0].value, ast.Constant)
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and isinstance(node.body[0].value.value, str)
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):
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emit_license(module, node.body[0].value.value)
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return "LICENSE"
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else:
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logger.info("ERROR: LICENSE() must return a string literal")
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return None
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else:
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logger.info("ERROR: LICENSE already defined")
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return None
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return None
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