Add configurable kernel modules list

[d4s]

Some distros have compiled-in kernel modules like ubuntu: CONFIG_VIRTIO=y

Fakemachine crashes with following log:

2017/11/08 16:30:47 open failed: /lib/modules/4.10.0-38-generic/kernel/drivers/virtio/virtio.ko - open /lib/modules/4.10.0-38-generic/kernel/drivers/virtio/virtio.ko: no such file or directory
--- FAIL: TestSuccessfullCommand (0.00s)
panic: open failed: /lib/modules/4.10.0-38-generic/kernel/drivers/virtio/virtio.ko - open /lib/modules/4.10.0-38-generic/kernel/drivers/virtio/virtio.ko: no such file or directory [recovered]
    panic: open failed: /lib/modules/4.10.0-38-generic/kernel/drivers/virtio/virtio.ko - open /lib/modules/4.10.0-38-generic/kernel/drivers/virtio/virtio.ko: no such file or directory

goroutine 5 [running]:
panic(0x64b6a0, 0xc4200f52e0)
    /usr/lib/go-1.7/src/runtime/panic.go:500 +0x1a1
testing.tRunner.func1(0xc420094180)
    /usr/lib/go-1.7/src/testing/testing.go:579 +0x25d
panic(0x64b6a0, 0xc4200f52e0)
    /usr/lib/go-1.7/src/runtime/panic.go:458 +0x243
log.Panicf(0x6ac7ed, 0x14, 0xc420053800, 0x2, 0x2)
    /usr/lib/go-1.7/src/log/log.go:327 +0xe3
github.com/go-debos/fakemachine/cpio.(*WriterHelper).CopyFileTo(0xc42000d5b0, 0xc420016d00, 0x3e, 0xc420016d00, 0x3e, 0x0, 0x0)
    /home/fredo/Documents/bos0009/go/src/github.com/go-debos/fakemachine/cpio/writerhelper.go:126 +0x1b1
github.com/go-debos/fakemachine/cpio.(*WriterHelper).CopyFile(0xc42000d5b0, 0xc420016d00, 0x3e, 0xc420016d00, 0x3e)
    /home/fredo/Documents/bos0009/go/src/github.com/go-debos/fakemachine/cpio/writerhelper.go:150 +0x49
github.com/go-debos/fakemachine.(*Machine).writerKernelModules(0xc420096400, 0xc42000d5b0, 0x2a, 0x6b64fc)
    /home/fredo/Documents/bos0009/go/src/github.com/go-debos/fakemachine/machine.go:326 +0x185
github.com/go-debos/fakemachine.(*Machine).startup(0xc420096400, 0x6a7933, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
    /home/fredo/Documents/bos0009/go/src/github.com/go-debos/fakemachine/machine.go:461 +0xae2
github.com/go-debos/fakemachine.(*Machine).Run(0xc420096400, 0x6a7933, 0x4, 0x5a032327, 0x10ad05ac, 0xc42002ff78)
    /home/fredo/Documents/bos0009/go/src/github.com/go-debos/fakemachine/machine.go:539 +0x5a
github.com/go-debos/fakemachine.TestSuccessfullCommand(0xc420094180)
    /home/fredo/Documents/bos0009/go/src/github.com/go-debos/fakemachine/machine_test.go:16 +0x48
testing.tRunner(0xc420094180, 0x6cacc0)
    /usr/lib/go-1.7/src/testing/testing.go:610 +0x81
created by testing.(*T).Run
    /usr/lib/go-1.7/src/testing/testing.go:646 +0x2ec
exit status 2
FAIL    github.com/go-debos/fakemachine    0.009s

[d4s]

The same thing for hardcoded libraries. On ALTLinux I have:

$ ./debos test.yaml 
2017/11/15 16:22:07 open failed: /lib/x86_64-linux-gnu/libc.so.6 - open /lib/x86_64-linux-gnu/libc.so.6: no such file or directory

[sjoerdsimons]

That's a seperate issue right ;)

[johnp]

Similar problem on Arch Linux, but it has the modules xz compressed:

$ debos simple.yaml
2018/06/27 22:44:21 open failed: /usr/lib/modules/4.16.16-1-ck-haswell/kernel/drivers/virtio/virtio.ko - open /usr/lib/modules/4.16.16-1-ck-haswell/kernel/drivers/virtio/virtio.ko: no such file or directory
$ la /usr/lib/modules/4.16.16-1-ck-haswell/kernel/drivers/virtio/virtio.ko.xz
.rw-r--r-- 4.5k root root 16 Jun 14:24 /usr/lib/modules/4.16.16-1-ck-haswell/kernel/drivers/virtio/virtio.ko.xz

edit: ran into half a dozen other problems after unzipping; for any other non-debian users: best to just run this in a vm for now. Too many debianisms.
edit2: fakemachine does not run in a vm either.

[andrewshadura]

Probably it should consult the running kernel to check if it has the module compiled in.

[ant9000]

Standard test for modules is

modinfo virtio_console

but you can test for in-kernel support by grepping for the symbols:

cat /proc/kallsyms |grep virtio_console

Tested with non privileged user on Ubuntu 14.04 and 18.04 - it works.

Antonio