#6258 Switch legacy signal() with sigaction()

[akleshchev]

Swap signal() with sigaction()

Due to a reported crash that wasn't reported to bugsplat, logs:

2026-09-24T16:02:07Z INFO #WebSocket# llcorehttp/llwebsocketmgr.cpp(252) start : Starting WebSocket server on port 9020 (localhost only)
2026-09-24T16:02:07Z WARNING #LLProcess# llcommon/llprocess.cpp(718) LLProcess::launch : Could not locate 'code' on PATH -- launch will likely fail
2026-09-24T16:02:07Z WARNING #LLProcess# llcommon/llprocess.cpp(559) LLProcess::create : Failed to create process: failed to create process: failed to launch code: default_launcher: No such file or directory [system:2 at /Users/runner/work/viewer/viewer/build-darwin-universal/packages/include/boost/process/v2/posix/default_launcher.hpp:409:78 in function 'basic_process<Executor> boost::process::posix::default_launcher::operator()(Executor, error_code &, const typename std::enable_if<net::execution::is_executor<Executor>::value || net::is_executor<Executor>::value, filesystem::path>::type &, Args &&, Inits &&...) [Executor = boost::asio::any_io_executor, Args = std::vector<std::string> &, Inits = <boost::process::process_stdio &>]']
2026-09-24T16:02:07Z WARNING #ScriptEditorWS# newview/llscripteditorws.cpp(402) launchVSCode : Failed to launch VS Code. Ensure the 'code' command is available on your PATH.
2026-09-24T16:02:07Z WARNING # newview/llappviewer.cpp(1403) doFrame :  Someone took over my signal/exception handler (post messagehandling)!

[Copilot]

Copilot review overview

🔵 Needs a closer look

The process-wide SIGPIPE disposition can overwrite the application's crash handler.

Review effort: Lite
Findings: None

What changed in this PR

This pull request replaces legacy signal() handling with sigaction() for SIGPIPE during process launches.

Changes:

• Configures SIGPIPE handling with sigaction().
• Preserves existing process-launch behavior.

File	Summary
indra/​llcommon/​llprocess.cpp	Replaces signal() with sigaction(), but still changes the process-wide SIGPIPE disposition.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

Copilot review overview

🟡 Changes recommended

Unresolved SIGPIPE lifetime and sigaction() error-handling issues remain.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1 · 1

Open (2)

• Keep SIGPIPE suppressed during asynchronous pipe writes · New
• Handle sigaction failure before restoring the previous disposition · New

[Copilot]

Copilot review overview

🟡 Changes recommended

One-time initialization can leave SIGPIPE assigned to the crash handler on later launches.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 1

Open (1)

• call_once leaves SIGPIPE crash handler after later launches · New

Resolved since last review (2)

• Keep SIGPIPE suppressed during asynchronous pipe writes
• Handle sigaction failure before restoring the previous disposition

[Copilot]

Copilot review overview

🟡 Changes recommended

Critical issues remain around deferred SIGPIPE protection and the missing direct <mutex> include.

Get a fresh assessment by requesting another Copilot review.

Review effort: Lite
Findings: 3

Open (3)

• SIGPIPE protection is deferred until first process launch · New
• Add direct <mutex> include for non-Windows std::call_once use · New
• call_once leaves SIGPIPE crash handler after later launches

[github-actions]

Thank you for your submission, we really appreciate it. Like many open-source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution. You can sign the CLA by just posting a Pull Request Comment same as the below format.

---

I have read the CLA Document and I hereby sign the CLA

---

1 out of 2 committers have signed the CLA.
✅ (akleshchev)[https://github.com/akleshchev]
❌ @Copilot
_{You can retrigger this bot by commenting recheck in this Pull Request. Posted by the CLA Assistant Lite bot.}