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33 lines
1.4 KiB
Python
33 lines
1.4 KiB
Python
import ast
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from llvmlite import ir
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def bpf_printk_emitter(call, module, builder, func):
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# Handle print statement
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for arg in call.args:
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if isinstance(arg, ast.Constant) and isinstance(arg.value, str):
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fmt_str = arg.value + "\n" + "\0"
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# Create a global variable for the format string
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fmt_gvar = ir.GlobalVariable(
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module, ir.ArrayType(ir.IntType(8), len(fmt_str)), name=f"{func.name}____fmt")
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fmt_gvar.global_constant = True
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fmt_gvar.initializer = ir.Constant( # type: ignore
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ir.ArrayType(ir.IntType(8), len(fmt_str)),
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bytearray(fmt_str.encode("utf8"))
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)
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fmt_gvar.linkage = "internal"
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fmt_gvar.align = 1 # type: ignore
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# Cast the global variable to i8*
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fmt_ptr = builder.bitcast(
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fmt_gvar, ir.PointerType())
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# Call bpf_trace_printk (assumed to be at address 6)
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fn_type = ir.FunctionType(ir.IntType(
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64), [ir.PointerType(), ir.IntType(32)], var_arg=True)
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fn_ptr_type = ir.PointerType(fn_type)
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fn_addr = ir.Constant(ir.IntType(64), 6)
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fn_ptr = builder.inttoptr(fn_addr, fn_ptr_type)
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# Call the function
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builder.call(fn_ptr, [fmt_ptr, ir.Constant(
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ir.IntType(32), len(fmt_str))], tail=True) |