src: rework early debug signal handling #615
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LGTM, and thanks. I agree that setting all the sighandlers to default is a good idea, SIG_IGN is inheritable across exec. For the record, I noticed this problem with a bug in some of my code that was masking out SIGCHLD until ppoll(), but I forgot that after forking I'd have to clear the procmask before execing node as a child process. That caused uv to never received SIGCHLD, and so to never notice child process exit. |
Execute the per-platform initialization logic as early as possible, for two reasons: 1. It opens the way for an upcoming commit to simplify early SIGUSR1 handling. 2. It should make life easier for embedders because io.js no longer mucks around with the file descriptor limit or signal disposition of the process. PR-URL: nodejs#615 Reviewed-By: Sam Roberts <[email protected]>
Instead of installing an early debug signal handler, simply block the SIGUSR1 signal at start-up and unblock it when the debugger is ready. Both approaches are functionally equivalent but blocking the signal accomplishes it in fewer lines of code. PR-URL: nodejs#615 Reviewed-By: Sam Roberts <[email protected]>
Signal dispositions are inherited by child processes. Restore ours to sane defaults in case our parent process changed it, to prevent quirky behavior when the parent does something silly like ignoring SIGSEGV. PR-URL: nodejs#615 Reviewed-By: Sam Roberts <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: #10539 Fixes: #10520 Refs: #615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: nodejs#10539 Fixes: nodejs#10520 Refs: nodejs#615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: nodejs#10539 Fixes: nodejs#10520 Refs: nodejs#615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: nodejs#10539 Fixes: nodejs#10520 Refs: nodejs#615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: nodejs#10539 Fixes: nodejs#10520 Refs: nodejs#615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: nodejs#10539 Fixes: nodejs#10520 Refs: nodejs#615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: nodejs#10539 Fixes: nodejs#10520 Refs: nodejs#615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: #10539 Fixes: #10520 Refs: #615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: #10539 Fixes: #10520 Refs: #615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: #10539 Fixes: #10520 Refs: #615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: #10539 Fixes: #10520 Refs: #615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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An application using node built as a shared library may legitimately implement its own signal handling routines. Current behaviour is to squash all signal handlers on node startup. This change will stop that behaviour when node is built as a shared library. PR-URL: #10539 Fixes: #10520 Refs: #615 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Gibson Fahnestock <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ben Noordhuis <[email protected]>
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Instead of installing an early debug signal handler, simply block the
SIGUSR1 signal at start-up and unblock it when the debugger is ready.
Both approaches are functionally equivalent but blocking the signal
accomplishes it in fewer lines of code.
R=@sam-github? It's not necessary to SIG_DFL SIGCHLD because
libuv installs its own handler when it spawns a process, but it does
seem like a good idea to explicitly install default handlers.
https://jenkins-iojs.nodesource.com/view/iojs/job/iojs+any-pr+multi/116/