[3621] | 1 | # What should happen if non-interactive shell gets SIGINT?
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| 2 |
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| 3 | (sleep 1; echo Sending SIGINT to main shell PID; exec kill -INT $$) &
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| 4 |
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| 5 | # We create a child which exits with 0 even on SIGINT
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| 6 | # (The complex command is necessary only if SIGINT is generated by ^C,
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| 7 | # in this testcase even bare "sleep 2" would do because
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| 8 | # in the testcase we don't send SIGINT *to the child*...)
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| 9 | $THIS_SH -c 'trap "exit 0" SIGINT; sleep 2'
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| 10 |
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| 11 | # In one second, we (main shell) get SIGINT here.
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| 12 | # The question is whether we should, or should not, exit.
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| 13 |
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| 14 | # bash will not stop here. It will execute next command(s).
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| 15 |
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| 16 | # The rationale for this is described here:
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| 17 | # http://www.cons.org/cracauer/sigint.html
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| 18 | #
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| 19 | # Basically, bash will not exit on SIGINT immediately if it waits
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| 20 | # for a child. It will wait for the child to exit.
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| 21 | # If child exits NOT by dying on SIGINT, then bash will not exit.
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| 22 | #
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| 23 | # The idea is that the following script:
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| 24 | # | emacs file.txt
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| 25 | # | more cmds
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| 26 | # User may use ^C to interrupt editor's ops like search. But then
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| 27 | # emacs exits normally. User expects that script doesn't stop.
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| 28 | #
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| 29 | # This is a nice idea, but detecting "did process really exit
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| 30 | # with SIGINT?" is racy. Consider:
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| 31 | # | bash -c 'while true; do /bin/true; done'
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| 32 | # When ^C is pressed while bash waits for /bin/true to exit,
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| 33 | # it may happen that /bin/true exits with exitcode 0 before
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| 34 | # ^C is delivered to it as SIGINT. bash will see SIGINT, then
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| 35 | # it will see that child exited with 0, and bash will NOT EXIT.
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| 36 |
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| 37 | # Therefore we do not implement bash behavior.
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| 38 | # I'd say that emacs need to put itself into a separate pgrp
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| 39 | # to isolate shell from getting stray SIGINTs from ^C.
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| 40 |
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| 41 | echo Next command after SIGINT was executed
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