mirror of
https://github.com/dart-lang/sdk
synced 2024-11-02 12:24:24 +00:00
b0c4ddf919
To create a Dart standalone executable on MacOS, we modify the dartaotruntime executable to add the snapshot contents, and the VM looks into the executable on disk to find the snapshot to load. Previously, we did this by adding a new 64-bit segment load command with a single section, where the section's file offset and size describes the inserted snapshot. This meant the Mach-O header size increased by 152 bytes. Originally, this wasn't an issue as there was plenty of padding, but later clang updates removed most of this padding, and so writing the new header actually overwrote the initial contents of the first section in the file, which happens to be the __text section. In addition, since the first section's offset was now declared to be within the header, utilities that strictly validated the Mach-O format, like codesign, would report errors. This CL changes it so that we actually reserve space in the dartaotruntime header using the -add_empty_section flag to the linker. In addition, we change from using a segment load command to using a (40 byte) note load command. This is because a segment load command specifies that the contents should be loaded in memory, but we don't use that loaded version. Instead, the VM reloads it from the executable on disk so it can appropriately mmap the different parts of the snapshot. A note section instead just declares a section of the executable as arbitrary data that the owner can read from the file and use as desired, which is semantically closer to our current usage. This CL also adds a test to pkg/dartdev/test/commands/compile_test to ensure that corrupting a random part of the snapshot in the executable causes signature verification to fail. This CL also reverts CL 256208, thus relanding the clang changes starting from June that originally raised awareness of the issue by greatly reduced the amount of padding after the load commands. TEST=pkg/dartdev/test/commands/compile_test Bug: https://github.com/dart-lang/sdk/issues/49783 Change-Id: Iee554d87b0eabaecd7a534ca4e4facfefbce6385 Cq-Include-Trybots: luci.dart.try:analyzer-mac-release-try,dart-sdk-mac-arm64-try,dart-sdk-mac-try,pkg-mac-release-arm64-try,pkg-mac-release-try,vm-kernel-precomp-mac-product-x64-try,vm-kernel-precomp-nnbd-mac-release-arm64-try Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/260108 Reviewed-by: Ryan Macnak <rmacnak@google.com> Reviewed-by: Daco Harkes <dacoharkes@google.com> Commit-Queue: Tess Strickland <sstrickl@google.com>
67 lines
1.3 KiB
C++
67 lines
1.3 KiB
C++
// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
#ifndef RUNTIME_PLATFORM_MACH_O_H_
|
|
#define RUNTIME_PLATFORM_MACH_O_H_
|
|
|
|
#include <platform/globals.h>
|
|
|
|
namespace dart {
|
|
|
|
namespace mach_o {
|
|
|
|
#pragma pack(push, 1)
|
|
|
|
typedef int cpu_type_t;
|
|
typedef int cpu_subtype_t;
|
|
typedef int vm_prot_t;
|
|
|
|
struct mach_header {
|
|
uint32_t magic;
|
|
cpu_type_t cputype;
|
|
cpu_subtype_t cpusubtype;
|
|
uint32_t filetype;
|
|
uint32_t ncmds;
|
|
uint32_t sizeofcmds;
|
|
uint32_t flags;
|
|
};
|
|
|
|
static const uint32_t MH_MAGIC = 0xfeedface;
|
|
static const uint32_t MH_CIGAM = 0xcefaedfe;
|
|
|
|
struct mach_header_64 {
|
|
uint32_t magic;
|
|
cpu_type_t cputype;
|
|
cpu_subtype_t cpusubtype;
|
|
uint32_t filetype;
|
|
uint32_t ncmds;
|
|
uint32_t sizeofcmds;
|
|
uint32_t flags;
|
|
uint32_t reserved;
|
|
};
|
|
|
|
static const uint32_t MH_MAGIC_64 = 0xfeedfacf;
|
|
static const uint32_t MH_CIGAM_64 = 0xcffaedfe;
|
|
|
|
struct load_command {
|
|
uint32_t cmd;
|
|
uint32_t cmdsize;
|
|
};
|
|
|
|
static const uint32_t LC_NOTE = 0x31;
|
|
struct note_command {
|
|
uint32_t cmd;
|
|
uint32_t cmdsize;
|
|
char data_owner[16];
|
|
uint64_t offset;
|
|
uint64_t size;
|
|
};
|
|
|
|
#pragma pack(pop)
|
|
|
|
} // namespace mach_o
|
|
|
|
} // namespace dart
|
|
|
|
#endif // RUNTIME_PLATFORM_MACH_O_H_
|