ninja-build/ninja

linux: `pool = console` does not forward signals (e.g. SIGTERM) to the console process

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#2,116 建立於 2022年4月2日

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 (2 留言) (0 反應) (0 負責人)C++ (10,194 star) (1,544 fork)batch import
bughelp wanted

描述

If I have a simple build.ninja:

rule sleep
  command = $
    echo hi $
    && sleep 100

build sleep : sleep
  pool = console

And I run ninja sleep, I get a process tree like this:

sh (PID: 1)
└─ ninja sleep (PID: 2)
   └─ sleep 100 (PID: 3)

If I now send a SIGTERM to ninja (kill 2), I’d expect that signal to be forwarded to sleep. However, ninja will swallow the signal and nothing happens. The same happens with e.g. SIGINT.

If I remove pool = console, the SIGTERM is forwarded correctly (this was fixed in https://github.com/ninja-build/ninja/pull/743) cc @nicolasdespres

Forwarding signals is quite important if I want to run ninja processes inside a service manager. For example if I want to run ninja sleep (or any program executable I build) inside of s6, s6-supervise will send SIGTERM (or any other signal) to ninja sleep, expecting it to stop running.

貢獻者指南

技術棧
cpp
領域
build system
議題類型
bug
難度面向新貢獻者的預計實作難度，1 表示很小改動，5 表示專家級工作。
3
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1-3 hours
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stale
清晰度議題是否清楚說明預期改動、驗收標準和下一步。
clear
前置要求
C++signal handlingprocess management
新手友善度1-100 的估計分數，表示該議題對首次貢獻者的友善程度。
55
研究方向
Investigate the signal forwarding mechanism in ninja's source code, specifically in `src/subprocess.cc` or related files. The issue notes that without `pool = console`, signals are forwarded correctly (fixed in PR #743). For the console pool, find where the process group is set or where signal handlers are configured. Compare the console pool implementation with the default pool to identify the missing signal forwarding. Look at how `SIGTERM` and `SIGINT` are handled in the subprocess code. Consider adding appropriate signal forwarding for console pool processes.