fix(process): skip wait/exit_code when prep-cmd fails with permission_denied in desktop mode

[Han-cy830]

Summary

• Fix incomplete permission_denied exception handling in proc_t::execute() prep-cmd loop
• When running in desktop mode (app.cmd is empty) and a prep-cmd fails with permission_denied (e.g., Session 0 isolation when screen is locked), the existing code already skips the run_command error. However, the subsequent child.wait() also returns permission_denied, which was not covered by the exception and caused execute() to return -1, triggering fail_guard to destroy the VDD and break streaming.

Root Cause

In the original code:

if (ec) {
    // ... skip permission_denied in desktop mode ✓
}
child.wait(ec);  // ← also returns permission_denied, NOT skipped ✗
if (ec) {
    return -1;  // ← triggers fail_guard → VDD destroyed → streaming breaks
}

Fix

Add a skip_prep_failure flag that, when set, also skips the wait() and exit_code() checks:

bool skip_prep_failure = false;
if (ec) {
    if (_app.cmd.empty() && ec == std::errc::permission_denied) {
        skip_prep_failure = true;
    } else {
        return -1;
    }
}
if (!skip_prep_failure) {
    child.wait(ec);
    // ... exit_code check
}

Testing

• Verified on Windows 11 with Sunshine running as SYSTEM service
• Unlocked screen: prep-cmd (SetDpi.exe) executes normally, DPI switching works
• Locked screen: prep-cmd fails with permission_denied but is skipped, streaming starts successfully (no DPI switching, as expected)
• Log confirms: Couldn't run [.\tools\SetDpi.exe 175]: System: permission_denied followed by successful [Desktop] execution

Files Changed

• src/process.cpp — proc_t::execute() prep-cmd loop only

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 0dfdde47-80b9-4674-b06c-edb60ecbdbd4

📥 Commits

Reviewing files that changed from the base of the PR and between 1bee5cb and 0639fa8.

📒 Files selected for processing (1)

• src/process.cpp

📜 Recent review details

🧰 Additional context used

📓 Path-based instructions (1)

src/**/*.{cpp,c,h}

⚙️ CodeRabbit configuration file

src/**/*.{cpp,c,h}: Sunshine 核心 C++ 源码，自托管游戏串流服务器。审查要点：内存安全、 线程安全、RAII 资源管理、安全漏洞。注意预处理宏控制的平台相关代码。

Files:

• src/process.cpp

🔇 Additional comments (1)

src/process.cpp (1)

246-248: LGTM!

Also applies to: 254-256, 261-271

---

Summary by CodeRabbit

发布说明

• Bug Fixes
  • 优化了桌面模式下预启动命令的权限异常处理，防止权限拒绝错误导致应用启动失败。

总览

proc_t::execute() 在执行预启动命令时新增了桌面模式下权限拒绝错误的特殊处理，通过引入 skip_prep_failure 标志来条件性地跳过进程等待和退出码验证步骤，避免该特定异常导致提前返回失败。

变更

预启动命令权限异常处理

层级 / 文件	摘要
预启动命令权限拒绝跳过机制 src/process.cpp	在 proc_t::execute() 的预启动阶段新增 skip_prep_failure 局部变量，当 platf::run_command 返回权限拒绝错误且应用命令为空（桌面模式）时，设置此标志以跳过后续的 wait() 和 exit_code() 失败处理；其他错误情况仍保持原有的错误返回行为。

预期审查工作量

🎯 3 (中等) | ⏱️ ~20 分钟

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	标题准确总结了主要变更：在桌面模式下当 prep-cmd 因权限拒绝而失败时跳过 wait/exit_code 检查，与 src/process.cpp 中的变更内容高度相关。
Description check	✅ Passed	描述详细说明了问题根源、解决方案、代码示例和测试验证，完全相关于 src/process.cpp 中的变更，提供了充分的上下文信息。
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}