[暂不合并]feat(service): disable THP before clipboard service startup

[mhduiy]

1. Add ExecStartPre script to disable Transparent Huge Pages before dde-clipboard-daemon and dde-clipboard services start
2. Use leading dash (-) to allow service startup even if THP disable script fails

Log: Disable THP before clipboard services start to improve performance

feat(service): 剪切板服务启动前禁用透明大页

1. 在 dde-clipboard-daemon 和 dde-clipboard 两个服务中增加 ExecStartPre 脚本，启动前禁用透明大页
2. 使用前置短横线 (-) 确保即使脚本失败也不影响服务正常启动

Log: 剪切板服务启动前禁用透明大页以提升性能
PMS: TASK-390043

Summary by Sourcery

Enhancements:

• Add a pre-start step to dde-clipboard-daemon and dde-clipboard systemd services to disable Transparent Huge Pages before service startup.

[deepin-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: mhduiy

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[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

This PR updates the systemd units for dde-clipboard-daemon and dde-clipboard to run a pre-start script that disables Transparent Huge Pages (THP) for performance, while allowing the services to continue starting even if the THP-disabling step fails.

File-Level Changes

Change	Details	Files
Run a pre-start THP disable script for clipboard-related systemd services without making service startup depend on its success.	Add an ExecStartPre command that invokes a script to disable Transparent Huge Pages before the daemon starts Prefix the ExecStartPre command with a leading dash so the service still starts if the THP disable command fails	misc/dde-clipboard-daemon.service.in
Apply the same THP pre-start behavior to the main clipboard systemd service as to the daemon.	Add an ExecStartPre command that invokes a script to disable Transparent Huge Pages before the clipboard service starts Prefix the ExecStartPre command with a leading dash so the service still starts if the THP disable command fails	misc/dde-clipboard.service.in

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[sourcery-ai]

Hey - I've left some high level feedback:

• Consider guarding the THP disable ExecStartPre commands with existence checks (e.g., ConditionPathExists or shell test -e around /sys/kernel/mm/transparent_hugepage/*) so the units behave cleanly on kernels or environments where THP is not exposed in the usual locations.
• If the same THP-disabling logic is duplicated in both service files, consider centralizing it in a single script or systemd unit to avoid divergence and make future changes easier.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- Consider guarding the THP disable ExecStartPre commands with existence checks (e.g., ConditionPathExists or shell `test -e` around `/sys/kernel/mm/transparent_hugepage/*`) so the units behave cleanly on kernels or environments where THP is not exposed in the usual locations.
- If the same THP-disabling logic is duplicated in both service files, consider centralizing it in a single script or systemd unit to avoid divergence and make future changes easier.

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[deepin-ci-robot]

deepin pr auto review

你好！我是CodeGeeX。我已仔细审查了你提供的 Git Diff 内容。本次修改主要为两个 DDE (Deepin Desktop Environment) 剪贴板相关的 systemd 服务单元文件增加了 ExecStartPre=-/usr/libexec/dde-thp-disable 配置项。

以下是我从语法逻辑、代码质量、代码性能和代码安全四个维度进行的审查与改进建议：

1. 语法逻辑

• 语法正确性：在 systemd 的 ExecStartPre 指令前加上 - 前缀是符合语法的。它的逻辑含义是“即使该命令执行失败（返回非零退出码），也继续执行后续的 ExecStart 操作”。这在处理可选的预处理脚本时是标准且正确的做法。
• 执行顺序逻辑：ExecStartPre 会在主进程 ExecStart 之前同步执行，逻辑上满足“在剪贴板服务启动前禁用 THP”的需求。

2. 代码质量

• 硬编码路径：/usr/libexec/dde-thp-disable 使用了硬编码的绝对路径。考虑到项目其他位置使用了 CMake 变量（如 @CMAKE_INSTALL_FULL_BINDIR@），建议保持一致性。
  • 改进建议：如果 dde-thp-disable 也是由该项目构建并安装的，建议在 CMake 配置中将 /usr/libexec 替换为对应的 CMake 变量（例如 @CMAKE_INSTALL_FULL_LIBEXECDIR@），以提高跨平台和不同发行版的兼容性。
• 代码重复：同样的修改在两个服务文件（dde-clipboard-daemon.service.in 和 dde-clipboard.service.in）中重复出现。如果未来需要修改，容易遗漏。
  • 改进建议：如果这两个服务高度相关，可以考虑在 CMake 层面通过 configure_file 共享同一段 Service 配置模板，或者确保有相应的文档/注释说明这两个文件需同步修改。

3. 代码性能

• 同步阻塞启动：ExecStartPre 是同步执行的。如果 /usr/libexec/dde-thp-disable 脚本内部涉及耗时操作（例如等待某个锁、或者执行复杂的磁盘I/O），将会延迟主服务的启动时间。
  • 改进建议：请确认该脚本的执行效率。对于桌面环境的核心组件（剪贴板），启动速度至关重要。该脚本应当是轻量级的，最好是瞬间完成的。如果只是写入如 /sys/kernel/mm/transparent_hugepage/enabled 这样的虚拟文件系统，性能不会有问题。
• 重复执行开销：如果 dde-clipboard-daemon 和 dde-clipboard 有可能同时启动，那么 dde-thp-disable 会被执行两次。
  • 改进建议：由于禁用 THP 通常是系统级别的操作，多次执行虽然不会出错，但属于冗余开销。如果这两个服务总是在同一个会话中启动，可以考虑将 THP 禁用的逻辑移至更上层的、仅启动一次的服务中（例如 session 初始化服务）。

4. 代码安全

• 权限与特权：修改透明大页（THP）通常需要 root 权限（例如向 /sys/kernel/mm/... 写入数据）。而当前 Service 的 Slice=session.slice 表明这是一个会话级别的服务，通常以普通用户身份运行。
  • 改进建议：请确认 /usr/libexec/dde-thp-disable 是否需要 root 权限。如果需要，该脚本必须配置了相应的权限提升机制（如 sudoers 配置、文件的 SUID 位、或者通过 systemd 的 systemd-sysusers/tmpfiles 赋予了特定Capability），否则该脚本会因为 Permission denied 静默失败（由于加了 - 前缀，主服务会继续启动，但 THP 实际上并未被禁用）。
• 脚本安全性：确保 /usr/libexec/dde-thp-disable 脚本本身的安全，防止被恶意替换或符号链接攻击。因为即使以普通用户运行，如果脚本具有 SUID 权限，被篡改将导致本地提权漏洞。建议该脚本的文件权限应严格限制为 root:root 755。
• TOCTOU 竞态条件：在服务启动时禁用 THP，如果系统中存在其他服务或定时任务在启用 THP，可能会产生竞态条件。不过对于 THP 这种系统级参数，通常设置后不会频繁变动，此风险较低。

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综合改进建议示例

如果你确认需要使用 CMake 变量来替代硬编码路径，修改后的 .service.in 文件应如下所示：

[Service]
Type=dbus
BusName=org.deepin.dde.daemon.Clipboard1
# 使用 CMake 变量替换硬编码路径，确保安装路径的一致性和可配置性
ExecStartPre=-@CMAKE_INSTALL_FULL_LIBEXECDIR@/dde-thp-disable
ExecStart=@CMAKE_INSTALL_FULL_BINDIR@/dde-clipboard-daemon
Slice=session.slice
Restart=on-failure

总结：本次修改逻辑清晰，语法正确，- 前缀的使用避免了预处理失败导致主服务无法启动的问题。重点需要关注的是脚本执行权限问题（普通用户服务能否成功修改内核THP参数）以及硬编码路径的规范性。

[mhduiy]

Ref:

• feat(thp): disable transparent huge pages for DDE daemon services dde-daemon#1126