bump version

Signed-off-by: varun-r-mallya <varunrmallya@gmail.com>

examples/c-form/ex7.bpf.c

@@ -1,34 +1,47 @@
 // SPDX-License-Identifier: GPL-2.0
+
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 
+struct trace_entry {
+  short unsigned int type;
+  unsigned char flags;
+  unsigned char preempt_count;
+  int pid;
+};
+
+struct trace_event_raw_sys_enter {
+  struct trace_entry ent;
+  long int id;
+  long unsigned int args[6];
+  char __data[0];
+};
 
 struct event {
-    __u32 pid;
+  __u32 pid;
-    __u32 uid;
+  __u32 uid;
-    __u64 ts;
+  __u64 ts;
 };
 
 struct {
-    __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+  __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
-    __uint(key_size, sizeof(int));
+  __uint(key_size, sizeof(int));
-    __uint(value_size, sizeof(int));
+  __uint(value_size, sizeof(int));
 } events SEC(".maps");
 
 SEC("tp/syscalls/sys_enter_setuid")
-int handle_setuid_entry(struct trace_event_raw_sys_enter *ctx)
+int handle_setuid_entry(struct trace_event_raw_sys_enter *ctx) {
-{
+  struct event data = {};
-    struct event data = {};
 
-    // Extract UID from the syscall arguments
+  // Extract UID from the syscall arguments
-    data.uid = (unsigned int)ctx->args[0];
+  data.uid = (unsigned int)ctx->args[0];
-    data.ts = bpf_ktime_get_ns();
+  data.ts = bpf_ktime_get_ns();
-    data.pid = bpf_get_current_pid_tgid() >> 32;
+  data.pid = bpf_get_current_pid_tgid() >> 32;
 
-    bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, &data, sizeof(data));
+  bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, &data, sizeof(data));
 
-    return 0;
+  return 0;
 }
 
 char LICENSE[] SEC("license") = "GPL";

examples/execve5.py

@@ -10,6 +10,7 @@ from ctypes import c_void_p, c_int64, c_int32, c_uint64
 class data_t:
     pid: c_uint64
     ts: c_uint64
+    comm: str(16)
 
 
 @bpf
@@ -24,9 +25,11 @@ def hello(ctx: c_void_p) -> c_int32:
     dataobj = data_t()
     ts = ktime()
     process_id = pid()
+    strobj = "hellohellohello"
     dataobj.pid = process_id
     dataobj.ts = ts
-    print(f"clone called at {ts} by pid {process_id}")
+    # dataobj.comm = strobj
+    print(f"clone called at {ts} by pid {process_id}, comm {strobj}")
     events.output(dataobj)
     return c_int32(0)
 

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "pythonbpf"
-version = "0.1.2"
+version = "0.1.3"
 description = "Reduced Python frontend for eBPF"
 authors = [
   { name = "r41k0u", email="pragyanshchaturvedi18@gmail.com" },

pythonbpf/binary_ops.py

@@ -15,6 +15,7 @@ def recursive_dereferencer(var, builder):
     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
@@ -24,7 +25,7 @@ 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 = recursive_dereferencer(local_sym_tab[left.id], builder)
+            left = recursive_dereferencer(local_sym_tab[left.id][0], builder)
         else:
             raise SyntaxError(f"Undefined variable: {left.id}")
     elif isinstance(left, ast.Constant):
@@ -34,7 +35,7 @@ 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 = recursive_dereferencer(local_sym_tab[right.id], builder)
+            right = recursive_dereferencer(local_sym_tab[right.id][0], builder)
         else:
             raise SyntaxError(f"Undefined variable: {right.id}")
     elif isinstance(right, ast.Constant):
@@ -46,36 +47,36 @@ def handle_binary_op(rval, module, builder, var_name, local_sym_tab, map_sym_tab
 
     if isinstance(op, ast.Add):
         builder.store(builder.add(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.Sub):
         builder.store(builder.sub(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.Mult):
         builder.store(builder.mul(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.Div):
         builder.store(builder.sdiv(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.Mod):
         builder.store(builder.srem(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.LShift):
         builder.store(builder.shl(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.RShift):
         builder.store(builder.lshr(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.BitOr):
         builder.store(builder.or_(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.BitXor):
         builder.store(builder.xor(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.BitAnd):
         builder.store(builder.and_(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     elif isinstance(op, ast.FloorDiv):
         builder.store(builder.udiv(left, right),
-                      local_sym_tab[var_name])
+                      local_sym_tab[var_name][0])
     else:
         raise SyntaxError("Unsupported binary operation")

pythonbpf/bpf_helper_handler.py

@@ -13,7 +13,7 @@ def bpf_ktime_get_ns_emitter(call, map_ptr, module, builder, func, local_sym_tab
     fn_ptr_type = ir.PointerType(fn_type)
     fn_ptr = builder.inttoptr(helper_id, fn_ptr_type)
     result = builder.call(fn_ptr, [], tail=False)
-    return result
+    return result, ir.IntType(64)
 
 
 def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
@@ -27,7 +27,7 @@ def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, func, local_sym_
     if isinstance(key_arg, ast.Name):
         key_name = key_arg.id
         if local_sym_tab and key_name in local_sym_tab:
-            key_ptr = local_sym_tab[key_name]
+            key_ptr = local_sym_tab[key_name][0]
         else:
             raise ValueError(
                 f"Key variable {key_name} not found in local symbol table.")
@@ -60,7 +60,7 @@ def bpf_map_lookup_elem_emitter(call, map_ptr, module, builder, func, local_sym_
 
     result = builder.call(fn_ptr, [map_void_ptr, key_ptr], tail=False)
 
-    return result
+    return result, ir.PointerType()
 
 
 def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
@@ -75,6 +75,7 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None,
         exprs = []
 
         for value in call.args[0].values:
+            print("Value in f-string:", ast.dump(value))
             if isinstance(value, ast.Constant):
                 if isinstance(value.value, str):
                     fmt_parts.append(value.value)
@@ -85,10 +86,25 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None,
                     raise NotImplementedError(
                         "Only string and integer constants are supported in f-string.")
             elif isinstance(value, ast.FormattedValue):
-                # Assume int for now
+                print("Formatted value:", ast.dump(value))
-                fmt_parts.append("%lld")
+                # TODO: Dirty handling here, only checks for int or str
                 if isinstance(value.value, ast.Name):
-                    exprs.append(value.value)
+                    if local_sym_tab and value.value.id in local_sym_tab:
+                        var_ptr, var_type = local_sym_tab[value.value.id]
+                        if isinstance(var_type, ir.IntType):
+                            fmt_parts.append("%lld")
+                            exprs.append(value.value)
+                        elif var_type == ir.PointerType(ir.IntType(8)):
+                            # Case with string
+                            fmt_parts.append("%s")
+                            exprs.append(value.value)
+                        else:
+                            raise NotImplementedError(
+                                "Only integer and pointer types are supported in formatted values.")
+                        print("Formatted value variable:", var_ptr, var_type)
+                    else:
+                        raise ValueError(
+                            f"Variable {value.value.id} not found in local symbol table.")
                 else:
                     raise NotImplementedError(
                         "Only simple variable names are supported in formatted values.")
@@ -120,7 +136,8 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None,
                 "Warning: bpf_printk supports up to 3 arguments, extra arguments will be ignored.")
 
         for expr in exprs[:3]:
-            val = eval_expr(func, module, builder, expr, local_sym_tab, None)
+            val, _ = eval_expr(func, module, builder,
+                               expr, local_sym_tab, None)
             if val:
                 if isinstance(val.type, ir.PointerType):
                     val = builder.ptrtoint(val, ir.IntType(64))
@@ -136,7 +153,6 @@ def bpf_printk_emitter(call, map_ptr, module, builder, func, local_sym_tab=None,
                 print(
                     "Warning: Failed to evaluate expression for bpf_printk argument. It will be converted to 0.")
                 args.append(ir.Constant(ir.IntType(64), 0))
-
         fn_type = ir.FunctionType(ir.IntType(
             64), [ir.PointerType(), ir.IntType(32)], var_arg=True)
         fn_ptr_type = ir.PointerType(fn_type)
@@ -189,7 +205,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, func, local_sym_
     if isinstance(key_arg, ast.Name):
         key_name = key_arg.id
         if local_sym_tab and key_name in local_sym_tab:
-            key_ptr = local_sym_tab[key_name]
+            key_ptr = local_sym_tab[key_name][0]
         else:
             raise ValueError(
                 f"Key variable {key_name} not found in local symbol table.")
@@ -208,7 +224,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, func, local_sym_
     if isinstance(value_arg, ast.Name):
         value_name = value_arg.id
         if local_sym_tab and value_name in local_sym_tab:
-            value_ptr = local_sym_tab[value_name]
+            value_ptr = local_sym_tab[value_name][0]
         else:
             raise ValueError(
                 f"Value variable {value_name} not found in local symbol table.")
@@ -231,7 +247,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, func, local_sym_
             flags_name = flags_arg.id
             if local_sym_tab and flags_name in local_sym_tab:
                 # Assume it's a stored integer value, load it
-                flags_ptr = local_sym_tab[flags_name]
+                flags_ptr = local_sym_tab[flags_name][0]
                 flags_val = builder.load(flags_ptr)
             else:
                 raise ValueError(
@@ -265,7 +281,7 @@ def bpf_map_update_elem_emitter(call, map_ptr, module, builder, func, local_sym_
     result = builder.call(
         fn_ptr, [map_void_ptr, key_ptr, value_ptr, flags_const], tail=False)
 
-    return result
+    return result, None
 
 
 def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
@@ -284,7 +300,7 @@ def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, func, local_sym_
     if isinstance(key_arg, ast.Name):
         key_name = key_arg.id
         if local_sym_tab and key_name in local_sym_tab:
-            key_ptr = local_sym_tab[key_name]
+            key_ptr = local_sym_tab[key_name][0]
         else:
             raise ValueError(
                 f"Key variable {key_name} not found in local symbol table.")
@@ -320,7 +336,7 @@ def bpf_map_delete_elem_emitter(call, map_ptr, module, builder, func, local_sym_
     # Call the helper function
     result = builder.call(fn_ptr, [map_void_ptr, key_ptr], tail=False)
 
-    return result
+    return result, None
 
 
 def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local_sym_tab=None, local_var_metadata=None):
@@ -337,7 +353,7 @@ def bpf_get_current_pid_tgid_emitter(call, map_ptr, module, builder, func, local
     # Extract the lower 32 bits (PID) using bitwise AND with 0xFFFFFFFF
     mask = ir.Constant(ir.IntType(64), 0xFFFFFFFF)
     pid = builder.and_(result, mask)
-    return pid
+    return pid, ir.IntType(64)
 
 
 def bpf_perf_event_output_handler(call, map_ptr, module, builder, func, local_sym_tab=None, struct_sym_tab=None, local_var_metadata=None):
@@ -350,7 +366,7 @@ def bpf_perf_event_output_handler(call, map_ptr, module, builder, func, local_sy
     if isinstance(data_arg, ast.Name):
         data_name = data_arg.id
         if local_sym_tab and data_name in local_sym_tab:
-            data_ptr = local_sym_tab[data_name]
+            data_ptr = local_sym_tab[data_name][0]
         else:
             raise ValueError(
                 f"Data variable {data_name} not found in local symbol table.")
@@ -386,7 +402,7 @@ def bpf_perf_event_output_handler(call, map_ptr, module, builder, func, local_sy
 
         result = builder.call(
             fn_ptr, [ctx_ptr, map_void_ptr, flags_val, data_void_ptr, size_val], tail=False)
-        return result
+        return result, None
     else:
         raise NotImplementedError(
             "Only simple object names are supported as data in perf event output.")

pythonbpf/codegen.py

@@ -93,6 +93,7 @@ def compile_to_ir(filename: str, output: str):
 
     module.add_named_metadata("llvm.ident", ["llvmlite PythonBPF v0.0.1"])
 
+    print(f"IR written to {output}")
     with open(output, "w") as f:
         f.write(f"source_filename = \"{filename}\"\n")
         f.write(str(module))
@@ -118,6 +119,7 @@ def compile():
 
     print(f"Object written to {o_file}, {ll_file} can be removed")
 
+
 def BPF() -> BpfProgram:
     caller_frame = inspect.stack()[1]
     caller_file = Path(caller_frame.filename).resolve()

pythonbpf/expr_pass.py

@@ -3,20 +3,20 @@ from llvmlite import ir
 
 
 def eval_expr(func, module, builder, expr, local_sym_tab, map_sym_tab, structs_sym_tab=None, local_var_metadata=None):
-    print(f"Evaluating expression: {expr}")
+    print(f"Evaluating expression: {ast.dump(expr)}")
     if isinstance(expr, ast.Name):
         if expr.id in local_sym_tab:
-            var = local_sym_tab[expr.id]
+            var = local_sym_tab[expr.id][0]
             val = builder.load(var)
-            return val
+            return val, local_sym_tab[expr.id][1]  # return value and type
         else:
             print(f"Undefined variable {expr.id}")
             return None
     elif isinstance(expr, ast.Constant):
         if isinstance(expr.value, int):
-            return ir.Constant(ir.IntType(64), expr.value)
+            return ir.Constant(ir.IntType(64), expr.value), ir.IntType(64)
         elif isinstance(expr.value, bool):
-            return ir.Constant(ir.IntType(1), int(expr.value))
+            return ir.Constant(ir.IntType(1), int(expr.value)), ir.IntType(1)
         else:
             print("Unsupported constant type")
             return None
@@ -37,15 +37,16 @@ def eval_expr(func, module, builder, expr, local_sym_tab, map_sym_tab, structs_s
                     return None
                 if isinstance(arg, ast.Name):
                     if arg.id in local_sym_tab:
-                        arg = local_sym_tab[arg.id]
+                        arg = local_sym_tab[arg.id][0]
                     else:
                         print(f"Undefined variable {arg.id}")
                         return None
                 if arg is None:
                     print("Failed to evaluate deref argument")
                     return None
+                # Since we are handling only name case, directly take type from sym tab
                 val = builder.load(arg)
-                return val
+                return val, local_sym_tab[expr.args[0].id][1]
 
             # check for helpers
             if expr.func.id in helper_func_list:

pythonbpf/functions_pass.py

@@ -51,36 +51,57 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
 
             if field_name in struct_info["fields"]:
                 field_idx = struct_info["fields"][field_name]
-                struct_ptr = local_sym_tab[var_name]
+                struct_ptr = local_sym_tab[var_name][0]
                 field_ptr = builder.gep(
                     struct_ptr, [ir.Constant(ir.IntType(32), 0),
                                  ir.Constant(ir.IntType(32), field_idx)],
                     inbounds=True)
                 val = eval_expr(func, module, builder, rval,
                                 local_sym_tab, map_sym_tab, structs_sym_tab)
+                if isinstance(struct_info["field_types"][field_idx], ir.ArrayType) and val[1] == ir.PointerType(ir.IntType(8)):
+                    # TODO: Figure it out, not a priority rn
+                    # Special case for string assignment to char array
+                    #str_len = struct_info["field_types"][field_idx].count
+                    #assign_string_to_array(builder, field_ptr, val[0], str_len)
+                    #print(f"Assigned to struct field {var_name}.{field_name}")
+                    pass
                 if val is None:
                     print("Failed to evaluate struct field assignment")
                     return
-                builder.store(val, field_ptr)
+                print(field_ptr)
+                builder.store(val[0], field_ptr)
                 print(f"Assigned to struct field {var_name}.{field_name}")
                 return
     elif isinstance(rval, ast.Constant):
         if isinstance(rval.value, bool):
             if rval.value:
                 builder.store(ir.Constant(ir.IntType(1), 1),
-                              local_sym_tab[var_name])
+                              local_sym_tab[var_name][0])
             else:
                 builder.store(ir.Constant(ir.IntType(1), 0),
-                              local_sym_tab[var_name])
+                              local_sym_tab[var_name][0])
             print(f"Assigned constant {rval.value} to {var_name}")
         elif isinstance(rval.value, int):
             # Assume c_int64 for now
             # var = builder.alloca(ir.IntType(64), name=var_name)
             # var.align = 8
             builder.store(ir.Constant(ir.IntType(64), rval.value),
-                          local_sym_tab[var_name])
+                          local_sym_tab[var_name][0])
             # local_sym_tab[var_name] = var
             print(f"Assigned constant {rval.value} to {var_name}")
+        elif isinstance(rval.value, str):
+            str_val = rval.value.encode('utf-8') + b'\x00'
+            str_const = ir.Constant(ir.ArrayType(
+                ir.IntType(8), len(str_val)), bytearray(str_val))
+            global_str = ir.GlobalVariable(
+                module, str_const.type, name=f"{var_name}_str")
+            global_str.linkage = 'internal'
+            global_str.global_constant = True
+            global_str.initializer = str_const
+            str_ptr = builder.bitcast(
+                global_str, ir.PointerType(ir.IntType(8)))
+            builder.store(str_ptr, local_sym_tab[var_name][0])
+            print(f"Assigned string constant '{rval.value}' to {var_name}")
         else:
             print("Unsupported constant type")
     elif isinstance(rval, ast.Call):
@@ -92,7 +113,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
                 # var = builder.alloca(ir_type, name=var_name)
                 # var.align = ir_type.width // 8
                 builder.store(ir.Constant(
-                    ir_type, rval.args[0].value), local_sym_tab[var_name])
+                    ir_type, rval.args[0].value), local_sym_tab[var_name][0])
                 print(f"Assigned {call_type} constant "
                       f"{rval.args[0].value} to {var_name}")
                 # local_sym_tab[var_name] = var
@@ -101,7 +122,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
                 # var.align = 8
                 val = handle_helper_call(
                     rval, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
-                builder.store(val, local_sym_tab[var_name])
+                builder.store(val[0], local_sym_tab[var_name][0])
                 # local_sym_tab[var_name] = var
                 print(f"Assigned constant {rval.func.id} to {var_name}")
             elif call_type == "deref" and len(rval.args) == 1:
@@ -112,7 +133,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
                     print("Failed to evaluate deref argument")
                     return
                 print(f"Dereferenced value: {val}, storing in {var_name}")
-                builder.store(val, local_sym_tab[var_name])
+                builder.store(val[0], local_sym_tab[var_name][0])
                 # local_sym_tab[var_name] = var
                 print(f"Dereferenced and assigned to {var_name}")
             elif call_type in structs_sym_tab and len(rval.args) == 0:
@@ -121,7 +142,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
                 # var = builder.alloca(ir_type, name=var_name)
                 # Null init
                 builder.store(ir.Constant(ir_type, None),
-                              local_sym_tab[var_name])
+                              local_sym_tab[var_name][0])
                 local_var_metadata[var_name] = call_type
                 print(f"Assigned struct {call_type} to {var_name}")
                 # local_sym_tab[var_name] = var
@@ -142,7 +163,7 @@ def handle_assign(func, module, builder, stmt, map_sym_tab, local_sym_tab, struc
                             rval, module, builder, func, local_sym_tab, map_sym_tab, structs_sym_tab, local_var_metadata)
                         # var = builder.alloca(ir.IntType(64), name=var_name)
                         # var.align = 8
-                        builder.store(val, local_sym_tab[var_name])
+                        builder.store(val[0], local_sym_tab[var_name][0])
                         # local_sym_tab[var_name] = var
             else:
                 print("Unsupported assignment call structure")
@@ -166,7 +187,7 @@ def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
             return None
     elif isinstance(cond, ast.Name):
         if cond.id in local_sym_tab:
-            var = local_sym_tab[cond.id]
+            var = local_sym_tab[cond.id][0]
             val = builder.load(var)
             if val.type != ir.IntType(1):
                 # Convert nonzero values to true, zero to false
@@ -183,12 +204,12 @@ def handle_cond(func, module, builder, cond, local_sym_tab, map_sym_tab):
             return None
     elif isinstance(cond, ast.Compare):
         lhs = eval_expr(func, module, builder, cond.left,
-                        local_sym_tab, map_sym_tab)
+                        local_sym_tab, map_sym_tab)[0]
         if len(cond.ops) != 1 or len(cond.comparators) != 1:
             print("Unsupported complex comparison")
             return None
         rhs = eval_expr(func, module, builder,
-                        cond.comparators[0], local_sym_tab, map_sym_tab)
+                        cond.comparators[0], local_sym_tab, map_sym_tab)[0]
         op = cond.ops[0]
 
         if lhs.type != rhs.type:
@@ -370,8 +391,14 @@ def allocate_mem(module, builder, body, func, ret_type, map_sym_tab, local_sym_t
                     var.align = ir_type.width // 8
                     print(
                         f"Pre-allocated variable {var_name} of type c_int64")
+                elif isinstance(rval.value, str):
+                    ir_type = ir.PointerType(ir.IntType(8))
+                    var = builder.alloca(ir_type, name=var_name)
+                    var.align = 8
+                    print(
+                        f"Pre-allocated variable {var_name} of type string")
                 else:
-                    print("Unsupported constant type")
+                    print(f"Unsupported constant type")
                     continue
             elif isinstance(rval, ast.BinOp):
                 # Assume c_int64 for now
@@ -383,7 +410,7 @@ def allocate_mem(module, builder, body, func, ret_type, map_sym_tab, local_sym_t
             else:
                 print("Unsupported assignment value type")
                 continue
-            local_sym_tab[var_name] = var
+            local_sym_tab[var_name] = (var, ir_type)
     return local_sym_tab
 
 
@@ -443,7 +470,6 @@ def process_bpf_chunk(func_node, module, return_type, map_sym_tab, structs_sym_t
 
     process_func_body(module, builder, func_node, func,
                       ret_type, map_sym_tab, structs_sym_tab)
-
     return func
 
 
@@ -519,3 +545,46 @@ def infer_return_type(func_node: ast.FunctionDef):
                 raise ValueError("Conflicting return types:"
                                  f"{found_type} vs {t}")
     return found_type or "None"
+
+# For string assignment to fixed-size arrays
+def assign_string_to_array(builder, target_array_ptr, source_string_ptr, array_length):
+    """
+    Copy a string (i8*) to a fixed-size array ([N x i8]*)
+    """
+    # Create a loop to copy characters one by one
+    entry_block = builder.block
+    copy_block = builder.append_basic_block("copy_char")
+    end_block = builder.append_basic_block("copy_end")
+    
+    # Create loop counter
+    i = builder.alloca(ir.IntType(32))
+    builder.store(ir.Constant(ir.IntType(32), 0), i)
+    
+    # Start the loop
+    builder.branch(copy_block)
+    
+    # Copy loop
+    builder.position_at_end(copy_block)
+    idx = builder.load(i)
+    in_bounds = builder.icmp_unsigned('<', idx, ir.Constant(ir.IntType(32), array_length))
+    builder.cbranch(in_bounds, copy_block, end_block)
+    
+    with builder.if_then(in_bounds):
+        # Load character from source
+        src_ptr = builder.gep(source_string_ptr, [idx])
+        char = builder.load(src_ptr)
+        
+        # Store character in target
+        dst_ptr = builder.gep(target_array_ptr, [ir.Constant(ir.IntType(32), 0), idx])
+        builder.store(char, dst_ptr)
+        
+        # Increment counter
+        next_idx = builder.add(idx, ir.Constant(ir.IntType(32), 1))
+        builder.store(next_idx, i)
+    
+    builder.position_at_end(end_block)
+    
+    # Ensure null termination
+    last_idx = ir.Constant(ir.IntType(32), array_length - 1)
+    null_ptr = builder.gep(target_array_ptr, [ir.Constant(ir.IntType(32), 0), last_idx])
+    builder.store(ir.Constant(ir.IntType(8), 0), null_ptr)

pythonbpf/structs_pass.py

@@ -28,14 +28,25 @@ def process_bpf_struct(cls_node, module):
 
     for item in cls_node.body:
         if isinstance(item, ast.AnnAssign) and isinstance(item.target, ast.Name):
+            print(f"Field: {item.target.id}, Type: "
+                  f"{ast.dump(item.annotation)}")
             field_names.append(item.target.id)
-            field_types.append(ctypes_to_ir(item.annotation.id))
+            if isinstance(item.annotation, ast.Call) and isinstance(item.annotation.func, ast.Name) and item.annotation.func.id == "str":
+                # This is a char array with fixed length
+                # TODO: For now assuming str is always called with constant
+                field_types.append(ir.ArrayType(
+                    ir.IntType(8), item.annotation.args[0].value))
+            else:
+                field_types.append(ctypes_to_ir(item.annotation.id))
 
     curr_offset = 0
     for ftype in field_types:
         if isinstance(ftype, ir.IntType):
             fsize = ftype.width // 8
             alignment = fsize
+        elif isinstance(ftype, ir.ArrayType):
+            fsize = ftype.count * (ftype.element.width // 8)
+            alignment = ftype.element.width // 8
         elif isinstance(ftype, ir.PointerType):
             fsize = 8
             alignment = 8
@@ -52,6 +63,7 @@ def process_bpf_struct(cls_node, module):
     structs_sym_tab[struct_name] = {
         "type": struct_type,
         "fields": {name: idx for idx, name in enumerate(field_names)},
-        "size": total_size
+        "size": total_size,
+        "field_types": field_types,
     }
     print(f"Created struct {struct_name} with fields {field_names}")