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cirosantilli / linux-kernel-module-cheat

The perfect emulation setup to study and develop the Linux kernel v5.4.3, kernel modules, QEMU, gem5 and x86_64, ARMv7 and ARMv8 userland and baremetal assembly, ANSI C, C++ and POSIX. GDB step debug and KGDB just work. Powered by Buildroot and crosstool-NG. Highly automated. Thoroughly documented. Automated tests. "Tested" in an Ubuntu 24.04 host.
https://cirosantilli.com/linux-kernel-module-cheat
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Questions: How to send signal to process inside QEMU? #17

Open poweihuang17 opened 6 years ago

poweihuang17 commented 6 years ago

Hi, Thanks for your always help. Do you know how to send signal to process inside QEMU? I'm using non-graphic mode like this: ./run -n ./buildroot/output.x86_64~/host/usr/bin/qemu-system-x86_64 -m 128M -monitor telnet::45454,server,nowait -netdev user,hostfwd=tcp::45455-:45455,id=net0 -smp 1 -M pc -append 'root=/dev/vda nopat nokaslr norandmaps printk.devkmsg=on printk.time=y console=ttyS0' -device edu -device lkmc_pci_min -device virtio-net-pci,netdev=net0 -drive file=./buildroot/output.x86_64~/images/rootfs.ext2,if=virtio,format=raw -kernel ./buildroot/output.x86_64~/images/bzImage -nographic I found this link, but do you know which should I connect to for "telnet::45454"?

poweihuang17 commented 6 years ago

BTW, I'm using no-graphic mode.

cirosantilli commented 6 years ago

Do you mean like hitting Ctrl + C to send SIGKILL to the foreground process in nographic mode?

Unfortunately I don't know how to do that well, it just kills QEMU itself, this is mentioned at the end of this section: https://github.com/cirosantilli/linux-kernel-module-cheat/blob/c771b40913eddd22809dc5504e44a1f3da9a4ede/getting-started.md#text-mode which link to Stack Exchange questions.

The best I can do for now is put on background with sleep 10 & and then kill $! or the like.

telnet::45454 is for the QEMU monitor, it allows interaction with QEMU itself, e.g. echo quit | ./qemumonitor to quit QEMU.

But the monitor has no knowledge of Linux or processes, so you shouldn't be able to send signals from there.

See this for a list of monitor commands: https://en.wikibooks.org/wiki/QEMU/Monitor