Add recursive dereferencing and get example working

demo/pybpf.py

@@ -1,9 +1,14 @@
 from pythonbpf import bpf, map, section, bpfglobal, compile
-from pythonbpf.helpers import ktime
+from pythonbpf.helpers import ktime, deref
 from pythonbpf.maps import HashMap
 
 from ctypes import c_void_p, c_int64, c_uint64
 
+# Instructions to how to run this program
+# 1. Install PythonBPF: pip install pythonbpf
+# 2. Run the program: python demo/pybpf.py
+# 3. Run the program with sudo: sudo examples/check.sh run demo/pybpf.o
+# 4. Start a Python repl and `import os` and then keep entering `os.sync()` to see reponses.
 
 @bpf
 @map
@@ -12,16 +17,20 @@ def last() -> HashMap:
 
 
 @bpf
-@section("tracepoint/syscalls/sys_sync")
+@section("tracepoint/syscalls/sys_enter_sync")
 def do_trace(ctx: c_void_p) -> c_int64:
     key = 0
     tsp = last().lookup(key)
     if tsp:
-        delta = (ktime() - tsp)
+        kt = ktime()
+        delta = (kt - tsp)
         if delta < 1000000000:
             time_ms = (delta // 1000000)
             print(f"sync called within last second, last {time_ms} ms ago")
         last().delete(key)
+    else:
+        kt = ktime()
+        last().update(key, kt)
     return c_int64(0)
 
 

examples/execve3.py

@@ -35,9 +35,11 @@ def hello_again(ctx: c_void_p) -> c_int64:
     ts = ktime()
     last().update(key, ts)
     
-    keema = 8
+    va = 8
-    keeda = keema * keema
+    nm = 5 ^ va
-    print(f"this is a variable {keeda}")
+    al = 6 & 3
+    ru = (nm + al) + al
+    print(f"this is a variable {ru}")
 #    st = "st"
 #   last().update(key, ts)
 

pythonbpf/binary_ops.py

@@ -1,7 +1,21 @@
 import ast
 from llvmlite import ir
 
-def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab):
+
+def recursive_dereferencer(var, builder):
+    """ dereference until primitive type comes out"""
+    if var.type == ir.PointerType(ir.PointerType(ir.IntType(64))):
+        a = builder.load(var)
+        return recursive_dereferencer(a, builder)
+    elif var.type == ir.PointerType(ir.IntType(64)):
+        a = builder.load(var)
+        return recursive_dereferencer(a, builder)
+    elif var.type == ir.IntType(64):
+        return var
+    else:
+        raise TypeError(f"Unsupported type for dereferencing: {var.type}")
+
+def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab, func):
     print(module)
     left = rval.left
     right = rval.right
@@ -10,7 +24,7 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
     # Handle left operand
     if isinstance(left, ast.Name):
         if left.id in local_sym_tab:
-            left = builder.load(local_sym_tab[left.id])
+            left = recursive_dereferencer(local_sym_tab[left.id], builder)
         else:
             raise SyntaxError(f"Undefined variable: {left.id}")
     elif isinstance(left, ast.Constant):
@@ -20,7 +34,7 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
 
     if isinstance(right, ast.Name):
         if right.id in local_sym_tab:
-            right = builder.load(local_sym_tab[right.id])  # Dereference the pre-assigned value
+            right = recursive_dereferencer(local_sym_tab[right.id], builder)
         else:
             raise SyntaxError(f"Undefined variable: {right.id}")
     elif isinstance(right, ast.Constant):
@@ -60,5 +74,8 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
     elif isinstance(op, ast.BitAnd):
         builder.store(builder.and_(left, right),
                       local_sym_tab[var_name])
+    elif isinstance(op, ast.FloorDiv):
+        builder.store(builder.udiv(left, right),
+                      local_sym_tab[var_name])
     else:
         raise SyntaxError("Unsupported binary operation")

pythonbpf/functions_pass.py

@@ -111,7 +111,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab):
             print("Unsupported assignment call function type")
     elif isinstance(rval, ast.BinOp):
         handle_binary_op(rval, module, builder, var_name,
-                         local_sym_tab, map_sym_tab)
+                         local_sym_tab, map_sym_tab, func)
     else:
         print("Unsupported assignment value type")
 
@@ -129,6 +129,15 @@ def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
         if cond.id in local_sym_tab:
             var = local_sym_tab[cond.id]
             val = builder.load(var)
+            if val.type != ir.IntType(1):
+                # Convert nonzero values to true, zero to false
+                if isinstance(val.type, ir.PointerType):
+                    # For pointer types, compare with null pointer
+                    zero = ir.Constant(val.type, None)
+                else:
+                    # For integer types, compare with zero
+                    zero = ir.Constant(val.type, 0)
+                val = builder.icmp_signed("!=", val, zero)
             return val
         else:
             print(f"Undefined variable {cond.id} in condition")