mirror of
https://github.com/JakeHillion/object-introspection.git
synced 2024-11-09 21:24:14 +00:00
9e2b48d713
Summary: Changes jitlog to use a memfd, an anonymous in memory file descriptor, rather than a file on disk. Also clean up this fd at the end of an OID run rather than leaving it in the hope it's valid next time. A previous attempt to land this used a `char*` from the OID process space in the remote target syscall. Somehow this works with our integration test target, but not globally. Changed to use the previous behaviour of putting the syscall arg in the empty text segment. In doing this I noticed that the text segment wouldn't be initialised at this point on a fresh process, so we were copying into effectively an uninitialised address. Move the jit log fd setup to after the segment setup accordingly. Test plan: - CI - Tested on an integration test target as before. Works. - Created a new target that definitely doesn't have this string in (simple for loop). Failed before, works now. Example: ```sh $ OID_TEST_ARGS='-fjit-logging' stest OidIntegration.simple_struct ... I1121 02:57:36.136890 500897 OIDebugger.cpp:269] Outputting JIT logs: I1121 02:57:36.136896 500897 OIDebugger.cpp:272] JITLOG: SimpleStruct @00007ffc639be180 I1121 02:57:36.136899 500897 OIDebugger.cpp:272] JITLOG: a @00007ffc639be180 I1121 02:57:36.136901 500897 OIDebugger.cpp:272] JITLOG: obj @00007ffc639be180 I1121 02:57:36.136904 500897 OIDebugger.cpp:272] JITLOG: b @00007ffc639be184 I1121 02:57:36.136905 500897 OIDebugger.cpp:272] JITLOG: obj @00007ffc639be184 I1121 02:57:36.136907 500897 OIDebugger.cpp:272] JITLOG: c @00007ffc639be188 I1121 02:57:36.136909 500897 OIDebugger.cpp:272] JITLOG: obj @00007ffc639be188 I1121 02:57:36.136911 500897 OIDebugger.cpp:278] Finished outputting JIT logs. ... ```
80 lines
2.5 KiB
C++
80 lines
2.5 KiB
C++
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <algorithm>
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#include <cstddef>
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#include <cstdint>
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extern "C" {
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#include <fcntl.h>
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#include <sys/syscall.h>
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#include <sys/types.h>
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}
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namespace {
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template <size_t N>
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struct StringLiteral {
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constexpr StringLiteral(const char (&str)[N]) {
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std::copy_n(str, N, value);
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}
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char value[N];
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};
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} // namespace
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/*
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* The Syscall structure describes a `syscall(2)` in a generic manner.
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* The struct is used by `OIDebugger::remoteSyscall` to define the return type
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* and statically check the number of arguments being passed. Currently, I don't
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* know how to use the _Args to also statically check the type of the arguments.
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* In the meantime, I can use the size of _Args to do a simple count check.
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*/
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template <StringLiteral _Name,
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unsigned long _SysNum,
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typename _RetType,
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typename... _Args>
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struct Syscall {
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/* User friendly syscall name */
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static constexpr auto Name = _Name.value;
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/* The syscall's number (see <sys/syscall.h>) */
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static constexpr unsigned long SysNum = _SysNum;
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/* The syscall's return type */
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using RetType = _RetType;
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/* The number of arguments the syscall takes */
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static constexpr size_t ArgsCount = sizeof...(_Args);
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static_assert(ArgsCount <= 6,
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"X64 syscalls support a maximum of 6 arguments");
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};
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/*
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* The list of syscalls we want to be able to use on the remote process.
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* The types passed to `struct Syscall` come directly from `man 2 <SYSCALL>`.
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* Don't hesitate to expand this list if you need more syscalls!
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*/
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using SysOpen = Syscall<"open", SYS_open, int, const char*, int, mode_t>;
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using SysClose = Syscall<"close", SYS_close, int, int>;
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using SysFsync = Syscall<"fsync", SYS_fsync, int, int>;
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using MemfdCreate =
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Syscall<"memfd_create", SYS_memfd_create, int, const char*, unsigned int>;
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using SysMmap =
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Syscall<"mmap", SYS_mmap, void*, void*, size_t, int, int, int, off_t>;
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using SysMunmap = Syscall<"munmap", SYS_munmap, int, void*, size_t>;
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