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Moved common tracepoint support into tracepoint.py
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,183 @@ | ||
| # Copyright 2016 Sasha Goldshtein | ||
| # | ||
| # Licensed under the Apache License, Version 2.0 (the "License"); | ||
| # you may not use this file except in compliance with the License. | ||
| # You may obtain a copy of the License at | ||
| # | ||
| # http:https://www.apache.org/licenses/LICENSE-2.0 | ||
| # | ||
| # Unless required by applicable law or agreed to in writing, software | ||
| # distributed under the License is distributed on an "AS IS" BASIS, | ||
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| # See the License for the specific language governing permissions and | ||
| # limitations under the License. | ||
|
|
||
| import ctypes as ct | ||
| import multiprocessing | ||
| import os | ||
| import re | ||
|
|
||
| class Perf(object): | ||
| class perf_event_attr(ct.Structure): | ||
| _fields_ = [ | ||
| ('type', ct.c_uint), | ||
| ('size', ct.c_uint), | ||
| ('config', ct.c_ulong), | ||
| ('sample_period', ct.c_ulong), | ||
| ('sample_type', ct.c_ulong), | ||
| ('IGNORE1', ct.c_ulong), | ||
| ('IGNORE2', ct.c_ulong), | ||
| ('wakeup_events', ct.c_uint), | ||
| ('IGNORE3', ct.c_uint), | ||
| ('IGNORE4', ct.c_ulong), | ||
| ('IGNORE5', ct.c_ulong), | ||
| ('IGNORE6', ct.c_ulong), | ||
| ('IGNORE7', ct.c_uint), | ||
| ('IGNORE8', ct.c_int), | ||
| ('IGNORE9', ct.c_ulong), | ||
| ('IGNORE10', ct.c_uint), | ||
| ('IGNORE11', ct.c_uint) | ||
| ] | ||
|
|
||
| NR_PERF_EVENT_OPEN = 298 | ||
| PERF_TYPE_TRACEPOINT = 2 | ||
| PERF_SAMPLE_RAW = 1024 | ||
| PERF_FLAG_FD_CLOEXEC = 8 | ||
| PERF_EVENT_IOC_SET_FILTER = 1074275334 | ||
| PERF_EVENT_IOC_ENABLE = 9216 | ||
|
|
||
| libc = ct.CDLL('libc.so.6', use_errno=True) | ||
| syscall = libc.syscall # not declaring vararg types | ||
| ioctl = libc.ioctl # not declaring vararg types | ||
|
|
||
| @staticmethod | ||
| def _open_for_cpu(cpu, attr): | ||
| pfd = Perf.syscall(Perf.NR_PERF_EVENT_OPEN, ct.byref(attr), | ||
| -1, cpu, -1, Perf.PERF_FLAG_FD_CLOEXEC) | ||
| if pfd < 0: | ||
| errno_ = ct.get_errno() | ||
| raise OSError(errno_, os.strerror(errno_)) | ||
| if Perf.ioctl(pfd, Perf.PERF_EVENT_IOC_SET_FILTER, | ||
| "common_pid == -17") < 0: | ||
| errno_ = ct.get_errno() | ||
| raise OSError(errno_, os.strerror(errno_)) | ||
| if Perf.ioctl(pfd, Perf.PERF_EVENT_IOC_ENABLE, 0) < 0: | ||
| errno_ = ct.get_errno() | ||
| raise OSError(errno_, os.strerror(errno_)) | ||
|
|
||
| @staticmethod | ||
| def perf_event_open(tpoint_id): | ||
| attr = Perf.perf_event_attr() | ||
| attr.config = tpoint_id | ||
| attr.type = Perf.PERF_TYPE_TRACEPOINT | ||
| attr.sample_type = Perf.PERF_SAMPLE_RAW | ||
| attr.sample_period = 1 | ||
| attr.wakeup_events = 1 | ||
| for cpu in range(0, multiprocessing.cpu_count()): | ||
| Perf._open_for_cpu(cpu, attr) | ||
|
|
||
| class Tracepoint(object): | ||
| enabled_tracepoints = [] | ||
| trace_root = "/sys/kernel/debug/tracing" | ||
| event_root = os.path.join(trace_root, "events") | ||
|
|
||
| @classmethod | ||
| def _any_tracepoints_enabled(cls): | ||
| return len(cls.enabled_tracepoints) > 0 | ||
|
|
||
| @classmethod | ||
| def generate_decl(cls): | ||
| if not cls._any_tracepoints_enabled(): | ||
| return "" | ||
| return "\nBPF_HASH(__trace_di, u64, u64);\n" | ||
|
|
||
| @classmethod | ||
| def generate_entry_probe(cls): | ||
| if not cls._any_tracepoints_enabled(): | ||
| return "" | ||
| return """ | ||
| int __trace_entry_update(struct pt_regs *ctx) | ||
| { | ||
| u64 tid = bpf_get_current_pid_tgid(); | ||
| u64 val = ctx->di; | ||
| __trace_di.update(&tid, &val); | ||
| return 0; | ||
| } | ||
| """ | ||
|
|
||
| def __init__(self, category, event, tp_id): | ||
| self.category = category | ||
| self.event = event | ||
| self.tp_id = tp_id | ||
|
|
||
| def _generate_struct_fields(self): | ||
| format_lines = Tracepoint.get_tpoint_format(self.category, | ||
| self.event) | ||
| text = "" | ||
| for line in format_lines: | ||
| match = re.search(r'field:([^;]*);.*size:(\d+);', line) | ||
| if match is None: | ||
| continue | ||
| parts = match.group(1).split() | ||
| field_name = parts[-1:][0] | ||
| field_type = " ".join(parts[:-1]) | ||
| field_size = int(match.group(2)) | ||
| if "__data_loc" in field_type: | ||
| continue | ||
| if field_name.startswith("common_"): | ||
| continue | ||
| text += " %s %s;\n" % (field_type, field_name) | ||
| return text | ||
|
|
||
| def generate_struct(self): | ||
| self.struct_name = self.event + "_trace_entry" | ||
| return """ | ||
| struct %s { | ||
| u64 __do_not_use__; | ||
| %s | ||
| }; | ||
| """ % (self.struct_name, self._generate_struct_fields()) | ||
|
|
||
| def generate_get_struct(self): | ||
| return """ | ||
| u64 tid = bpf_get_current_pid_tgid(); | ||
| u64 *di = __trace_di.lookup(&tid); | ||
| if (di == 0) { return 0; } | ||
| struct %s tp = {}; | ||
| bpf_probe_read(&tp, sizeof(tp), (void *)*di); | ||
| """ % self.struct_name | ||
|
|
||
| @classmethod | ||
| def enable_tracepoint(cls, category, event): | ||
| tp_id = cls.get_tpoint_id(category, event) | ||
| if tp_id == -1: | ||
| raise ValueError("no such tracepoint found: %s:%s" % | ||
| (category, event)) | ||
| Perf.perf_event_open(tp_id) | ||
| new_tp = Tracepoint(category, event, tp_id) | ||
| cls.enabled_tracepoints.append(new_tp) | ||
| return new_tp | ||
|
|
||
| @staticmethod | ||
| def get_tpoint_id(category, event): | ||
| evt_dir = os.path.join(Tracepoint.event_root, category, event) | ||
| try: | ||
| return int( | ||
| open(os.path.join(evt_dir, "id")).read().strip()) | ||
| except: | ||
| return -1 | ||
|
|
||
| @staticmethod | ||
| def get_tpoint_format(category, event): | ||
| evt_dir = os.path.join(Tracepoint.event_root, category, event) | ||
| try: | ||
| return open(os.path.join(evt_dir, "format")).readlines() | ||
| except: | ||
| return "" | ||
|
|
||
| @classmethod | ||
| def attach(cls, bpf): | ||
| if cls._any_tracepoints_enabled(): | ||
| bpf.attach_kprobe(event="tracing_generic_entry_update", | ||
| fn_name="__trace_entry_update") | ||
|
|
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