id = 2337
title = "Os boot issues on 9p filesystem due to unix domain sockets open failure"
state = "closed"
created_at = "2024-05-08T09:53:25.856Z"
closed_at = "2024-12-11T18:14:04.559Z"
labels = ["block:9p"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/2337"
host-os = "Ubuntu 22.04 LTS"
host-arch = "s390x ( but any is affected)"
qemu-version = "QEMU emulator version 6.2.0 (Debian 1:6.2+dfsg-2ubuntu6.16)"
guest-os = "Ubuntu (23.11)"
guest-arch = "s390x"
description = """Unix filesystem API is broken, unix domain socket special files return an error at open()"""
reproduce = """Simple script. Tries to use netcat to get data through a local unix domain socket file   
```
#!/bin/bash

# Cleanup target dir
[ -d ./target ] && rm -rf target
mkdir target

# Add configuration updates
mkdir -p ./target/etc/initramfs-tools/
echo 9p >> ./target/etc/initramfs-tools/modules
echo 9pnet_virtio >> ./target/etc/initramfs-tools/modules

# Add the test script
cat > ./target/test_init << EOF
#!/bin/bash

echo "Test for unix domain sockets"

nc -Ul /socket &
sleep 1
echo "Sockets work" | nc -UN /socket || echo "Sockets fail"

echo o > /proc/sysrq-trigger
sleep 999
EOF
chmod 700 ./target/test_init

# Create an Ubuntu 23.10 around it
echo "Creating Ubuntu target OS"
debootstrap --variant=minbase\\
            --include=udev,kmod,initramfs-tools,systemd,netcat-openbsd,linux-image-generic \\
            --exclude=man,bash-completion \\
            mantic ./target > /dev/null || exit 1

# Run the test in 9p forwarded filesystem
echo "Running OS in qemu"
qemu-system-s390x \\
  -m 8192 \\
  -smp 4 \\
  -nodefaults -nographic -no-reboot -no-user-config \\
  -kernel ./target/boot/vmlinuz \\
  -initrd ./target/boot/initrd.img \\
  -append 'root=fsRoot rw rootfstype=9p rootflags=trans=virtio,version=9p2000.L,msize=512000,cache=mmap,posixacl console=ttysclp0 init=/test_init quiet' \\
  -fsdev local,security_model=passthrough,multidevs=remap,id=fsdev-fsRoot,path=./target \\
  -device virtio-9p-pci,id=fsRoot,fsdev=fsdev-fsRoot,mount_tag=fsRoot \\
  -device virtio-serial-ccw -device sclpconsole,chardev=console \\
  -chardev stdio,id=console,signal=off 
```"""
additional = """Test output:
```
Test for unix domain sockets
qemu-system-s390x: 9p: broken or compromised client detected; attempt to open special file (i.e. neither regular file, nor directory)
nc: No such device or address
nc: /socket: No such file or directory
Sockets fail
```"""