56 lines
1.3 KiB
Markdown
56 lines
1.3 KiB
Markdown
# mod_hello
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## building
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```shell
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make all
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```
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This produces `./helloctl/helloctl` binary for talking to the `mod_hello` over
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ioctl through `/dev/helloctl`, as well as `./mod_hello.ko` kernel module
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itself.
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## Testing
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### Host
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```shell
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$> make build
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$> sudo insmod ./mod_hello.ko
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$> sudo dmesg | tail
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[ 1679.566426] [mod_hello] pid: 8418, comm: insmod
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[ 1679.566427] [mod_hello] module loaded.
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[ 1679.566428] [mod_hello] looking up 'files'
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[ 1679.574011] [mod_hello] files 0xffffffff87e57e40
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[ 1679.574013] [mod_hello] files (0xffffffff87e57e40): usage
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[ 1679.579120] [mod_hello] fib of 0 and 1 (up to 10000000): 8644293272739028509 (in only 5 jiffies)
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$> sudo ./helloctl/helloctl
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$> sudo dmesg | tail -1
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[ 1734.248270] [mod_hello] received command: 1
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```
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### Container
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Running ioctl's inside containers is a little tricky.
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Assuming we've already `insmod` the module above:
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```shell
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sudo docker run -it --rm -v $(pwd)/helloctl/helloctl:/usr/bin/helloctl:ro -v /dev/helloctl:/dev/helloctl:ro fedora /usr/bin/helloctl
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```
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You'll get a failure `Could not open /dev/helloctl`
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```shell
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sudo docker run -it --rm -v $(pwd)/helloctl/helloctl:/usr/bin/helloctl:ro -v /dev/helloctl:/dev/helloctl:ro --privileged fedora /usr/bin/helloctl
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```
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Now `dmesg | tail` will reflect the command ran successfully.
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### cleanup
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```shell
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make clean
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sudo rmmod mod_hello
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```
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