Fix SIGINT handler to use sigaction with SA_ONSTACK flag #7312
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Related to Z3Prover#7305 Update SIGINT signal handler to use `sigaction` with `SA_ONSTACK` flag. * Replace `signal` function with `sigaction` function in `src/util/scoped_ctrl_c.cpp` to register the SIGINT handler. * Set the `SA_ONSTACK` flag for the SIGINT signal handler in `src/util/scoped_ctrl_c.cpp`. * Update `on_ctrl_c` function to use `sigaction` in `src/util/scoped_ctrl_c.cpp`. * Modify `scoped_ctrl_c` struct in `src/util/scoped_ctrl_c.h` to include `struct sigaction m_old_action` instead of `void (STD_CALL *m_old_handler)(int)`. --- For more details, open the [Copilot Workspace session](https://copilot-workspace.githubnext.com/Z3Prover/z3/issues/7305?shareId=XXXX-XXXX-XXXX-XXXX).
| m_old_handler = signal(SIGINT, on_ctrl_c); | ||
| struct sigaction sa; | ||
| sa.sa_handler = on_ctrl_c; | ||
| sa.sa_flags = SA_ONSTACK; |
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but without calling sigaltstack, isn't this useless?
My man page says:
Call the signal handler on an alternate signal stack
provided by sigaltstack(2). If an alternate stack is not
available, the default stack will be used. This flag is
meaningful only when establishing a signal handler.
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It is what Github WorkSpaces provided in the first shot.
Besides looking suspicious, it also isn't cross-platform. For Windows, we would not use this.
Then also, I am not sure if the code in 'shell' is broken because it only considers sigint.
Altogether more than a quick change, but something that you as the highest esteemed and glorious expert in operating sophisticated machinery may find a spare moment to consider when not occupied near sunny grass lawns or ocean side camps (it is August, isn't it?).
Related to #7305
Update SIGINT signal handler to use
sigactionwithSA_ONSTACKflag.signalfunction withsigactionfunction insrc/util/scoped_ctrl_c.cppto register the SIGINT handler.SA_ONSTACKflag for the SIGINT signal handler insrc/util/scoped_ctrl_c.cpp.on_ctrl_cfunction to usesigactioninsrc/util/scoped_ctrl_c.cpp.scoped_ctrl_cstruct insrc/util/scoped_ctrl_c.hto includestruct sigaction m_old_actioninstead ofvoid (STD_CALL *m_old_handler)(int).For more details, open the Copilot Workspace session.