Get ex2 running

Author: varun-r-mallya

Makefile

@@ -1,13 +1,13 @@
 compile:
 	chmod +x ./tools/compile.py
-	./tools/compile.py ./examples/execve.py
+	./tools/compile.py ./examples/execve2.py
 
 install: 
 	pip install -e .
 
 clean:
 	rm -rf build dist *.egg-info
-	rm -rf examples/execve.ll examples/execve.o
+	rm -rf examples/*.ll examples/*.o
 
 all: install compile
 

README.md

@@ -8,6 +8,9 @@ Step 2. Run `make` to see the compilation output of the example.
 Step 3. Run `check.sh` to check if generated object file passes through the verifier inside the examples directory.  
 Step 4. Run `make` in the `examples/c-form` directory to modify the example C BPF program to check the actual LLVM IR generated by clang.  
 
+### Development Notes
+Run ` ./check.sh run execve2.o;` in examples folder
+
 ## Authors
 - [@r41k0u](https://github.com/r41k0u)
 - [@varun-r-mallya](https://github.com/varun-r-mallya)

examples/c-form/Makefile

@@ -1,19 +1,19 @@
 BPF_CLANG := clang
 CFLAGS := -O2 -emit-llvm -target bpf -c
 
-SRC := ex3.bpf.c
-OUT := ex3.bpf.ll
-OBJECT := ex3.bpf.o
+SRC := $(wildcard *.bpf.c)
+LL := $(SRC:.bpf.c=.bpf.ll)
+OBJ := $(SRC:.bpf.c=.bpf.o)
 
 .PHONY: all clean
 
-all: $(OUT)
-	
-object: $(SRC)
-	$(BPF_CLANG) -O2 -g -target bpf -c $< -o $(OBJECT)
+all: $(LL) $(OBJ)
 
-$(OUT): $(SRC) object
+%.bpf.o: %.bpf.c
+	$(BPF_CLANG) -O2 -target bpf -c $< -o $@
+
+%.bpf.ll: %.bpf.c
 	$(BPF_CLANG) $(CFLAGS) -S $< -o $@
 
 clean:
-	rm -f $(OUT) $(OBJECT)
+	rm -f $(LL) $(OBJ)

examples/c-form/ex2.bpf.c

@@ -1,7 +1,7 @@
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 
-SEC("kprobe/sys_clone")
+SEC("tracepoint/syscalls/sys_enter_execve")
 int hello(struct pt_regs *ctx) {
     bpf_printk("Hello, World!\n");
     return 0;

examples/check.sh

@@ -1,2 +1,33 @@
 #!/bin/bash
-sudo bpftool prog -d load $1 /sys/fs/bpf/tmp && sudo rm -f /sys/fs/bpf/tmp
+
+PIN_PATH="/sys/fs/bpf/bpf_prog"
+FILE="$2"
+case "$1" in
+    check)
+        echo "[*] Checking $FILE"
+        echo $(sudo bpftool prog load -d "$FILE" "$PIN_PATH")
+        sudo rm -f "$PIN_PATH"
+        echo "[+] Verification succeeded"
+        ;;
+    run)
+        echo "[*] Loading and running $FILE"
+        sudo bpftool prog load "$FILE" "$PIN_PATH" autoattach
+        echo "[+] Program loaded. Press Ctrl+C to stop"
+        sudo cat /sys/kernel/debug/tracing/trace_pipe
+        sudo rm -f "$PIN_PATH"
+        echo "[+] Stopped"
+        ;;
+    stop)
+        echo "[*] Stopping program"
+        sudo rm -f "$PIN_PATH"
+        echo "[+] Stopped"
+        ;;
+    *)
+        echo "Usage: $0 <check|run|stop> <file.o>"
+        echo "Examples:"
+        echo "  $0 check program.bpf.o"
+        echo "  $0 run program.bpf.o"
+        echo "  $0 stop"
+        exit 1
+        ;;
+esac

examples/execve2.py

@@ -1,13 +1,11 @@
 from pythonbpf.decorators import bpf, section
-# from pythonbpf.decorators import tracepoint, syscalls
 from ctypes import c_void_p, c_int32
 
 
 @bpf
-@section("kprobe/sys_clone")
+@section("tracepoint/syscalls/sys_enter_execve")
 def hello(ctx: c_void_p) -> c_int32:
     print("Hello, World!")
     return c_int32(0)
 
-
 LICENSE = "GPL"

examples/hello_world.py

@@ -1,11 +1,15 @@
-from pythonbpf.decorators import tracepoint, syscalls
+# This is what it is going to look like
+# pylint: disable-all# type: ignore
+from pythonbpf.decorators import tracepoint, syscalls, bpfglobal, bpf
 from ctypes import c_void_p, c_int32
 
-
+@bpf
 @tracepoint(syscalls.sys_clone)
 def trace_clone(ctx: c_void_p) -> c_int32:
     print("Hello, World!")
     return c_int32(0)
 
-
-LICENSE = "GPL"
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"

pythonbpf/codegen.py

@@ -1,8 +1,8 @@
 import ast
 from llvmlite import ir
 from .license_pass import license_processing
-from .functions_pass import func_proc, functions_processing
-from .constants_pass import constants_processing
+from .functions_pass import func_proc
+# from .constants_pass import constants_processing
 from .globals_pass import globals_processing
 
 
@@ -28,12 +28,10 @@ def processor(source_code, filename, module):
 
     func_proc(tree, module, bpf_chunks)
     # For now, we will parse the BPF specific parts of AST
-    # Big rewrite
 
-    # will worry later
     # constants_processing(tree, module)
-    # license_processing(tree, module)
-    # globals_processing(tree, module)
+    license_processing(tree, module)
+    globals_processing(tree, module)
     # functions_processing(tree, module)
 
 
@@ -57,6 +55,7 @@ def compile_to_ir(filename: str, output: str):
     module.add_named_metadata("llvm.ident", ["llvmlite PythonBPF v0.0.0"])
 
     with open(output, "w") as f:
+        f.write(f"source_filename = \"{filename}\"\n")
         f.write(str(module))
 
     return output

pythonbpf/functions_pass.py

@@ -13,9 +13,9 @@ def emit_function(module: ir.Module, name: str):
     param.add_attribute("nocapture")
 
     func.attributes.add("nounwind")
-#    func.attributes.add("\"frame-pointer\"=\"all\"")
-#    func.attributes.add("no-trapping-math", "true")
-#    func.attributes.add("stack-protector-buffer-size", "8")
+    # func.attributes.add("\"frame-pointer\"=\"all\"")
+    # func.attributes.add("no-trapping-math", "true")
+    # func.attributes.add("stack-protector-buffer-size", "8")
 
     block = func.append_basic_block(name="entry")
     builder = ir.IRBuilder(block)
@@ -70,17 +70,17 @@ def process_func_body(module, builder, func_node, func):
                 # Handle print statement
                 for arg in call.args:
                     if isinstance(arg, ast.Constant) and isinstance(arg.value, str):
-                        fmt_str = arg.value + "\n"
+                        fmt_str = arg.value + "\n" + "\0"
                         # Create a global variable for the format string
                         fmt_gvar = ir.GlobalVariable(
                             module, ir.ArrayType(ir.IntType(8), len(fmt_str)), name=f"{func.name}____fmt")
                         fmt_gvar.global_constant = True
-                        fmt_gvar.initializer = ir.Constant(
+                        fmt_gvar.initializer = ir.Constant(     # type: ignore
                             ir.ArrayType(ir.IntType(8), len(fmt_str)),
                             bytearray(fmt_str.encode("utf8"))
                         )
                         fmt_gvar.linkage = "internal"
-                        fmt_gvar.align = 1
+                        fmt_gvar.align = 1      # type: ignore
 
                         # Cast the global variable to i8*
                         fmt_ptr = builder.bitcast(
@@ -129,6 +129,8 @@ def process_bpf_chunk(func_node, module):
 
     func.linkage = "dso_local"
     func.attributes.add("nounwind")
+    func.attributes.add("noinline")
+    func.attributes.add("optnone")
 
     if func_node.args.args:
         # Only look at the first argument for now

pythonbpf/globals_pass.py

@@ -31,8 +31,8 @@ def globals_processing(tree, module: ir.Module):
     collected = ["LICENSE"]
 
     for node in tree.body:
-        if isinstance(node, ast.FunctionDef) and len(node.decorator_list) == 1:
-            dec = node.decorator_list[0]
+        if isinstance(node, ast.FunctionDef) and len(node.decorator_list) == 2:
+            dec = node.decorator_list[1]
             if (
                 isinstance(dec, ast.Call)
                 and isinstance(dec.func, ast.Name)