Merge pull request #13 from pythonbpf/ringbuf

Add ringbuf support

Author: varun-r-mallya

pythonbpf/debuginfo/debug_info_generator.py

@@ -21,6 +21,10 @@ def get_basic_type(self, name: str, size: int, encoding: int) -> Any:
             )
         return self._type_cache[key]
 
+    def get_int32_type(self) -> Any:
+        """Get debug info for signed 32-bit integer"""
+        return self.get_basic_type("int", 32, dc.DW_ATE_signed)
+
     def get_uint32_type(self) -> Any:
         """Get debug info for unsigned 32-bit integer"""
         return self.get_basic_type("unsigned int", 32, dc.DW_ATE_unsigned)

pythonbpf/maps/__init__.py

@@ -1,4 +1,4 @@
-from .maps import HashMap, PerfEventArray
+from .maps import HashMap, PerfEventArray, RingBuf
 from .maps_pass import maps_proc
 
-__all__ = ["HashMap", "PerfEventArray", "maps_proc"]
+__all__ = ["HashMap", "PerfEventArray", "maps_proc", "RingBuf"]

pythonbpf/maps/maps.py

@@ -1,3 +1,4 @@
+# This file provides type  and function hints only and does not actually give any functionality.
 class HashMap:
     def __init__(self, key, value, max_entries):
         self.key = key
@@ -33,3 +34,18 @@ def __init__(self, key_size, value_size):
 
     def output(self, data):
         pass  # Placeholder for output method
+
+
+class RingBuf:
+    def __init__(self, max_entries):
+        self.max_entries = max_entries
+
+    def reserve(self, size: int, flags=0):
+        if size > self.max_entries:
+            raise ValueError("size cannot be greater than set maximum entries")
+        return 0
+
+    def submit(self, data, flags=0):
+        pass
+
+    # add discard, output and also give names to flags and stuff

pythonbpf/maps/maps_pass.py

@@ -1,19 +1,20 @@
 import ast
+from logging import Logger
 from llvmlite import ir
 from enum import Enum
 from .maps_utils import MapProcessorRegistry
 from ..debuginfo import DebugInfoGenerator
 import logging
 
-logger = logging.getLogger(__name__)
+logger: Logger = logging.getLogger(__name__)
 
 
 def maps_proc(tree, module, chunks):
     """Process all functions decorated with @map to find BPF maps"""
     map_sym_tab = {}
     for func_node in chunks:
         if is_map(func_node):
-            print(f"Found BPF map: {func_node.name}")
+            logger.info(f"Found BPF map: {func_node.name}")
             map_sym_tab[func_node.name] = process_bpf_map(func_node, module)
     return map_sym_tab
 
@@ -26,8 +27,41 @@ def is_map(func_node):
 
 
 class BPFMapType(Enum):
+    UNSPEC = 0
     HASH = 1
+    ARRAY = 2
+    PROG_ARRAY = 3
     PERF_EVENT_ARRAY = 4
+    PERCPU_HASH = 5
+    PERCPU_ARRAY = 6
+    STACK_TRACE = 7
+    CGROUP_ARRAY = 8
+    LRU_HASH = 9
+    LRU_PERCPU_HASH = 10
+    LPM_TRIE = 11
+    ARRAY_OF_MAPS = 12
+    HASH_OF_MAPS = 13
+    DEVMAP = 14
+    SOCKMAP = 15
+    CPUMAP = 16
+    XSKMAP = 17
+    SOCKHASH = 18
+    CGROUP_STORAGE_DEPRECATED = 19
+    CGROUP_STORAGE = 19
+    REUSEPORT_SOCKARRAY = 20
+    PERCPU_CGROUP_STORAGE_DEPRECATED = 21
+    PERCPU_CGROUP_STORAGE = 21
+    QUEUE = 22
+    STACK = 23
+    SK_STORAGE = 24
+    DEVMAP_HASH = 25
+    STRUCT_OPS = 26
+    RINGBUF = 27
+    INODE_STORAGE = 28
+    TASK_STORAGE = 29
+    BLOOM_FILTER = 30
+    USER_RINGBUF = 31
+    CGRP_STORAGE = 32
 
 
 def create_bpf_map(module, map_name, map_params):
@@ -51,7 +85,7 @@ def create_bpf_map(module, map_name, map_params):
 
 
 def create_map_debug_info(module, map_global, map_name, map_params):
-    """Generate debug information metadata for BPF map"""
+    """Generate debug information metadata for BPF maps HASH and PERF_EVENT_ARRAY"""
     generator = DebugInfoGenerator(module)
 
     uint_type = generator.get_uint32_type()
@@ -112,6 +146,60 @@ def create_map_debug_info(module, map_global, map_name, map_params):
     return global_var
 
 
+def create_ringbuf_debug_info(module, map_global, map_name, map_params):
+    """Generate debug information metadata for BPF RINGBUF map"""
+    generator = DebugInfoGenerator(module)
+
+    int_type = generator.get_int32_type()
+
+    type_array = generator.create_array_type(
+        int_type, map_params.get("type", BPFMapType.RINGBUF).value
+    )
+    type_ptr = generator.create_pointer_type(type_array, 64)
+    type_member = generator.create_struct_member("type", type_ptr, 0)
+
+    max_entries_array = generator.create_array_type(int_type, map_params["max_entries"])
+    max_entries_ptr = generator.create_pointer_type(max_entries_array, 64)
+    max_entries_member = generator.create_struct_member(
+        "max_entries", max_entries_ptr, 64
+    )
+
+    elements_arr = [type_member, max_entries_member]
+
+    struct_type = generator.create_struct_type(elements_arr, 128, is_distinct=True)
+
+    global_var = generator.create_global_var_debug_info(
+        map_name, struct_type, is_local=False
+    )
+    map_global.set_metadata("dbg", global_var)
+    return global_var
+
+
+@MapProcessorRegistry.register("RingBuf")
+def process_ringbuf_map(map_name, rval, module):
+    """Process a BPF_RINGBUF map declaration"""
+    logger.info(f"Processing Ringbuf: {map_name}")
+    map_params = {"type": BPFMapType.RINGBUF}
+
+    # Parse max_entries if present
+    if len(rval.args) >= 1 and isinstance(rval.args[0], ast.Constant):
+        const_val = rval.args[0].value
+        if isinstance(const_val, int):
+            map_params["max_entries"] = const_val
+
+    for keyword in rval.keywords:
+        if keyword.arg == "max_entries" and isinstance(keyword.value, ast.Constant):
+            const_val = keyword.value.value
+            if isinstance(const_val, int):
+                map_params["max_entries"] = const_val
+
+    logger.info(f"Ringbuf map parameters: {map_params}")
+
+    map_global = create_bpf_map(module, map_name, map_params)
+    create_ringbuf_debug_info(module, map_global, map_name, map_params)
+    return map_global
+
+
 @MapProcessorRegistry.register("HashMap")
 def process_hash_map(map_name, rval, module):
     """Process a BPF_HASH map declaration"""

tests/c-form/ex8.bpf.c

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <linux/types.h>
+
+// Define the structure to be sent via ringbuf
+struct event {
+    __u32 pid;
+    __u32 uid;
+    __u64 timestamp;
+    char comm[16];  // Process name
+};
+
+// Define the ringbuffer map
+struct {
+    __uint(type, BPF_MAP_TYPE_RINGBUF);
+    __uint(max_entries, 256 * 1024); // 256 KB
+} events SEC(".maps");
+
+// Tracepoint for execve system calls
+SEC("tracepoint/syscalls/sys_enter_execve")
+int trace_execve(void *ctx)
+{
+    struct event *e;
+    __u64 pid_tgid;
+    __u64 uid_gid;
+
+    // Reserve space in the ringbuffer
+    e = bpf_ringbuf_reserve(&events, sizeof(*e), 0);
+    if (!e)
+        return 0;
+
+    // Fill the struct with data
+    pid_tgid = bpf_get_current_pid_tgid();
+    e->pid = pid_tgid >> 32;
+
+    uid_gid = bpf_get_current_uid_gid();
+    e->uid = uid_gid & 0xFFFFFFFF;
+
+    e->timestamp = bpf_ktime_get_ns();
+
+    bpf_get_current_comm(&e->comm, sizeof(e->comm));
+
+    // Submit the event to ringbuffer
+    bpf_ringbuf_submit(e, 0);
+
+    return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";

tests/c-form/ringbuf.bpf.c

@@ -0,0 +1,45 @@
+from pythonbpf import bpf, map, struct, section, bpfglobal, compile
+from pythonbpf.helpers import ktime, pid
+from pythonbpf.maps import PerfEventArray
+
+from ctypes import c_void_p, c_int32, c_uint64
+
+
+# PLACEHOLDER EXAMPLE. THIS SHOULD TECHNICALLY STILL FAIL TESTS
+@bpf
+@struct
+class data_t:
+    pid: c_uint64
+    ts: c_uint64
+    comm: str(16)
+
+
+@bpf
+@map
+def events() -> PerfEventArray:
+    return PerfEventArray(key_size=c_int32, value_size=c_int32)
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_clone")
+def hello(ctx: c_void_p) -> c_int32:
+    dataobj = data_t()
+    ts = ktime()
+    strobj = "hellohellohello"
+    dataobj.pid = pid()
+    dataobj.ts = ktime()
+    # dataobj.comm = strobj
+    print(
+        f"clone called at {dataobj.ts} by pid {dataobj.pid}, comm {strobj} at time {ts}"
+    )
+    events.output(dataobj)
+    return c_int32(0)
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile()

tests/failing_tests/perf_buffer_map.py

@@ -0,0 +1,35 @@
+from pythonbpf import bpf, BPF, map, bpfglobal, section, compile, compile_to_ir
+from pythonbpf.maps import RingBuf, HashMap
+from ctypes import c_int32, c_void_p
+
+
+# Define a map
+@bpf
+@map
+def mymap() -> RingBuf:
+    return RingBuf(max_entries=(1024))
+
+
+@bpf
+@map
+def mymap2() -> HashMap:
+    return HashMap(key=c_int32, value=c_int32, max_entries=1024)
+
+
+@bpf
+@section("tracepoint/syscalls/sys_enter_clone")
+def random_section(ctx: c_void_p) -> c_int32:
+    print("Hello")
+    return c_int32(0)
+
+
+@bpf
+@bpfglobal
+def LICENSE() -> str:
+    return "GPL"
+
+
+compile_to_ir("ringbuf.py", "ringbuf.ll")
+compile()
+b = BPF()
+b.load_and_attach()