Completely empty /etc/resolv.conf

[NoaHimesaka1873]

Installed the newly-released Steam wrapper, and it complains about no internet connection. So I dug deeper and tried to access muvm shell, Much to my surprise, /etc/resolv.conf is completely empty!
Happens with systemd-resolved + Tailsacle, and NetworkManager internal DNS management + no Tailscale too.

[teohhanhui]

Try this command to get some more logging:

RUST_LOG='muvm=debug,muvm_guest=debug,muvm_server=debug' RUST_BACKTRACE=1 muvm -e=RUST_BACKTRACE bash

[NoaHimesaka1873]

[2024-10-10T15:34:17Z DEBUG muvm] sched_setaffinity cpuset=CpuSet { cpu4, cpu5, cpu6, cpu7 }
[2024-10-10T15:34:17Z DEBUG muvm] krun_set_vm_config num_vcpus=4 ram_mib=12508
[2024-10-10T15:34:17Z DEBUG muvm::net] passing fd to passt fd=6
[2024-10-10T15:34:17Z DEBUG muvm::env] env vars env={"XAUTHORITY": "/run/user/1000/xauth_HRAaVO", "HOST_DISPLAY": ":0", "RUST_LOG": "muvm=debug,muvm_guest=debug,muvm_server=debug", "PATH": "/home/noahimesaka/.pyenv/plugins/pyenv-virtualenv/shims:/home/noahimesaka/.pyenv/shims:/home/noahimesaka/.pyenv/bin:/home/noahimesaka/.local/bin:/home/noahimesaka/.sdkman/candidates/java/current/bin:/home/noahimesaka/.sdkman/candidates/gradle/current/bin:/home/noahimesaka/.cargo/bin:/usr/lib64/ccache:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/noahimesaka/.local/share/JetBrains/Toolbox/scripts", "RUST_BACKTRACE": "1", "MESA_LOADER_DRIVER_OVERRIDE": "asahi"}
Using default interface naming scheme 'v255'.
Failed to open /usr/lib/udev/rules.d/60-nfs.rules, ignoring: Permission denied
[2024-10-10T15:34:24Z DEBUG muvm::guest::net] dhcpcd output output=Output { status: ExitStatus(unix_wait_status(0)), stdout: "", stderr: "dhcpcd-10.0.8 starting\nDropped protocol specifier '.link' from 'eth0.link'. Using 'eth0' (ifindex=2).\nsd_bus_open_system: No such file or directory\neth0: waiting for carrier\neth0: carrier acquired\nduid_get: cannot write duid: Permission denied\nDUID 00:03:00:01:5a:94:ef:e4:0c:ee\neth0: IAID ef:e4:0c:ee\neth0: soliciting a DHCP lease\neth0: offered 172.30.1.22 from 172.30.1.254\neth0: probing address 172.30.1.22/24\neth0: leased 172.30.1.22 for infinity\ndhcp_writefile: /var/lib/dhcpcd/eth0.lease: Permission denied\neth0: adding route to 172.30.1.0/24\neth0: adding default route via 172.30.1.254\nDropped protocol specifier '.dhcp' from 'eth0.dhcp'. Using 'eth0' (ifindex=2).\nsd_bus_open_system: No such file or directory\n" }
[2024-10-10T15:34:24Z DEBUG muvm::guest::sommelier] exec command="/usr/bin/muvm-server" command_args=["bash"]
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Unsupported maximum keycode 708, clipping.
>                   X11 cannot support keycodes above 255.
Errors from xkbcomp are not fatal to the X server
noahimesaka@WATATEN-An-Angel-Flew-Down-to-Me:~$ thread 'main' panicked at src/client.rs:157:60:
called `Result::unwrap()` on an `Err` value: ETIMEDOUT
stack backtrace:
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

noahimesaka@WATATEN-An-Angel-Flew-Down-to-Me:~$ exit
exit
FATAL <sommelier.cc:2963> sl_handle_x_connection_event: got error or hangup (mask 5) on X connection, exiting

[teohhanhui]

I can reproduce the problem while using dhcpcd. Looks like something broke at some point. Using dhcp-client (dhclient) seems to work (but it's deprecated...)

[NoaHimesaka1873]

@teohhanhui Then is there any way to force the use of dhclient for the time being?

[teohhanhui]

sudo dnf swap dhcpcd dhcp-client

[stella23456789]

sudo dnf swap dhcpcd dhcp-client

I did this, it installed but now when launching steam it just does invisible window and does nothing else

[ddxtanx]

I'm experiencing basically the same issue - though from the perspective of running steam and encountering a http 0 error when trying to download from cdn.steamstatic.com. When running the debug muvm command, even if I perform the right configuration with either dhcp clients the /etc/resolv.conf file inside the vm is always empty. For reference I'll include the outputs of trying to dig from the vm with either dhcp-client or dhcpcd as the dhcp backend:
dhcp-client:

[2024-10-11T02:49:56Z DEBUG muvm] sched_setaffinity cpuset=CpuSet { cpu2, cpu3, cpu4, cpu5, cpu6, cpu7, c
[2024-10-11T02:49:56Z DEBUG muvm] krun_set_vm_config num_vcpus=8 ram_mib=12451
[2024-10-11T02:49:56Z DEBUG muvm::net] passing fd to passt fd=6
[2024-10-11T02:49:56Z DEBUG muvm::env] env vars env={"MESA_LOADER_DRIVER_OVERRIDE": "asahi", "RUST_BACKTRACE": "1", "PATH": "/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/us:/home/ddxtanx/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/git:/home/ddxtanx/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/command-not-found:/home/ddxtanx/.antigen/bundles/zsh-users/zsh-completions:/home/ddxtanx/.antigen/bundles/zsh-users/zsh-syntax-highlighting:/home/ddxtanx/.antigen/bundles/MichaelAquilina/zsh-auto-notify:/home/ddxtanx/.antigen/bundles/MichaelAquilina/zsh-you-should-use:/home/ddxtanx/.antigen/bundles/aubreypwd/zsh-plugin-fd-1.0.0:/home/ddxtanx/.antigen/bundles/romkatv/powerlevel10k:/home/ddxtanx/.local/opt:/home/ddxtanx/.cargo/bin:/usr/sbin:/home/ddxtanx/.local/bin:/home/ddxtanx/go/bin", "RUST_LOG": "muvm=debug,muvm_guest=debug,muvm_server=debug", "HOST_DISPLAY": ":0"}
Couldn't get any nameserver address
No IPv4 nameserver available for DHCP
Using default interface naming scheme 'v255'.
Failed to open /usr/lib/udev/rules.d/60-nfs.rules, ignoring: Permission denied
[2024-10-11T02:49:58Z DEBUG muvm::guest::net] dhclient output output=Output { status: ExitStatus(unix_wait_status(0)), stdout: "", stderr: "" }
[2024-10-11T02:49:58Z DEBUG muvm::guest::sommelier] exec command="/usr/bin/muvm-server" command_args=["bash"]
[ddxtanx@ddxmacx ~]$ The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Unsupported maximum keycode 708, clipping.
>                   X11 cannot support keycodes above 255.
Errors from xkbcomp are not fatal to the X server
dig google.com
;; communications error to 127.0.0.1#53: connection refused
;; communications error to 127.0.0.1#53: connection refused
;; communications error to 127.0.0.1#53: connection refused

; <<>> DiG 9.18.28 <<>> google.com
;; global options: +cmd
;; no servers could be reached

[ddxtanx@ddxmacx ~]$ echo "nameserver 192.168.2.2" > /etc/resolv.conf
[ddxtanx@ddxmacx ~]$ dig google.com

; <<>> DiG 9.18.28 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39675
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com.   IN A

;; ANSWER SECTION:
google.com.  219 IN A 172.217.4.78

;; Query time: 10 msec
;; SERVER: 192.168.2.2#53(192.168.2.2) (UDP)
;; WHEN: Thu Oct 10 21:50:16 CDT 2024
;; MSG SIZE  rcvd: 5

dhcpcd:

[2024-10-11T02:42:11Z DEBUG muvm] sched_setaffinity cpuset=CpuSet { cpu2, cpu3, cpu4, cpu5, cpu6, cpu7, cpu8, cpu9 }
[2024-10-11T02:42:11Z DEBUG muvm] krun_set_vm_config num_vcpus=8 ram_mib=12451
[2024-10-11T02:42:11Z DEBUG muvm::net] passing fd to passt fd=6
[2024-10-11T02:42:11Z DEBUG muvm::env] env vars env={"RUST_LOG": "muvm=debug,muvm_guest=debug,muvm_server=debug", "RUST_BACKTRACE": "1", "PATH": "/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/home/ddxtanx/.antigen/bundles/robbyrussell/oh-my-zsh/lib:/home/ddxtanx/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/dirhistory:/home/ddxtanx/.antigen/bundles/zsh-users/zsh-autosuggestions:/home/ddxtanx/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/git:/home/ddxtanx/.antigen/bundles/robbyrussell/oh-my-zsh/plugins/command-not-found:/home/ddxtanx/.antigen/bundles/zsh-users/zsh-completions:/home/ddxtanx/.antigen/bundles/zsh-users/zsh-syntax-highlighting:/home/ddxtanx/.antigen/bundles/MichaelAquilina/zsh-auto-notify:/home/ddxtanx/.antigen/bundles/MichaelAquilina/zsh-you-should-use:/home/ddxtanx/.antigen/bundles/aubreypwd/zsh-plugin-fd-1.0.0:/home/ddxtanx/.antigen/bundles/romkatv/powerlevel10k:/home/ddxtanx/.local/opt:/home/ddxtanx/.cargo/bin:/usr/sbin:/home/ddxtanx/.local/bin:/home/ddxtanx/go/bin", "HOST_DISPLAY": ":0", "MESA_LOADER_DRIVER_OVERRIDE": "asahi"}
Couldn't get any nameserver address
No IPv4 nameserver available for DHCP
Using default interface naming scheme 'v255'.
Failed to open /usr/lib/udev/rules.d/60-nfs.rules, ignoring: Permission denied
[2024-10-11T02:42:18Z DEBUG muvm::guest::net] dhcpcd output output=Output { status: ExitStatus(unix_wait_status(0)), stdout: "", stderr: "dhcpcd-10.0.8 starting\nDUID 00:01:00:01:2e:9b:40:81:fa:7c:50:dd:00:65\neth0: waiting for carrier\neth0: carrier acquired\neth0: IAID ef:e4:0c:ee\neth0: rebinding lease of 192.168.2.75\neth0: probing address 192.168.2.51/24\neth0: leased 192.168.2.51 for infinity\neth0: adding route to 192.168.2.0/24\neth0: adding default route via 192.168.2.1\n" }
[2024-10-11T02:42:18Z DEBUG muvm::guest::sommelier] exec command="/usr/bin/muvm-server" command_args=["bash"]
The XKEYBOARD keymap compiler (xkbcomp) reports:
> Warning:          Unsupported maximum keycode 708, clipping.
>                   X11 cannot support keycodes above 255.
Errors from xkbcomp are not fatal to the X server
[ddxtanx@ddxmacx ~]$ echo "nameserver 192.168.2.2" > /etc/resolv.conf
[ddxtanx@ddxmacx ~]$ dig google.com

; <<>> DiG 9.18.28 <<>> google.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 51992
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com.   IN A

;; ANSWER SECTION:
google.com.  291 IN A 172.217.4.78

;; Query time: 40 msec
;; SERVER: 192.168.2.2#53(192.168.2.2) (UDP)
;; WHEN: Thu Oct 10 21:44:01 CDT 2024
;; MSG SIZE  rcvd: 55

(to get dhcpcd functionality, all that was necessary was to make /var/lib/dhcpcd world readable and writable, though I'm sure more fine-grained permissions could be given depending on what user the muvm process runs as.)

Unlike the above, though, no matter which dhcp client I use, no window opens up at all.

[ddxtanx]

As a hotfix, I've edited ~/.local/share/fex-steam/steam-launcher/bin_steam.sh to include echo "nameserver [YOUR DNS SERVER]" >> /etc/resolv.conf at the top of the file. Then steam/muvm seems to be able to connect to all links with no issue! :)

[theoparis]

Permission denied

I am encountering the same issue with dhcpcd installed.

 cannot write duid: Permission denied

The mentioned fix of adding to /etc/resolv.conf doesn't fix dhcpcd unfortunately.

[kaazoo]

Hi, I have the same problem on Ubuntu Asahi when running a Ubuntu 24.10 based root FS:

$ RUST_LOG='muvm=trace,muvm_guest=trace,muvm_server=trace' RUST_BACKTRACE=1 LD_LIBRARY_PATH=/usr/local/lib64 muvm --passt-socket=/tmp/passt_1.socket FEXBash
[2024-11-21T23:40:02Z DEBUG muvm] sched_setaffinity cpuset=CpuSet { cpu4, cpu5, cpu6, cpu7, cpu8, cpu9, cpu10, cpu11 }
[2024-11-21T23:40:02Z DEBUG muvm] krun_set_vm_config num_vcpus=8 ram_mib=25342
[2024-11-21T23:40:02Z DEBUG muvm::env] env vars env={"XAUTHORITY": "/run/user/XXX/.mutter-Xwaylandauth.LOCWW2", "PATH": "/home/XXX/.local/bin:/home/XXX/.cargo/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin:/snap/bin:/home/XXX/.cargo/bin", "HOST_DISPLAY": ":0", "LD_LIBRARY_PATH": "/usr/local/lib64", "MESA_LOADER_DRIVER_OVERRIDE": "asahi", "RUST_LOG": "muvm=trace,muvm_guest=trace,muvm_server=trace"}
Using default interface naming scheme 'v255'.
[2024-11-21T23:40:08Z DEBUG muvm::guest::net] dhcpcd output output=Output { status: ExitStatus(unix_wait_status(0)), stdout: "", stderr: "dhcpcd-10.0.6 starting\nmkdir: cannot create directory '/var/lib/ntp': Permission denied\nDropped protocol specifier '.link' from 'eth0.link'. Using 'eth0' (ifindex=2).\nsd_bus_open_system: No such file or directory\nmkdir: cannot create directory '/var/lib/ntp': Permission denied\neth0: waiting for carrier\neth0: carrier acquired\nmkdir: cannot create directory '/var/lib/ntp': Permission denied\nduid_get: cannot write duid: Permission denied\nDUID XXX\neth0: IAID XXX\nipv6_readsecret: cannot write secret: Permission denied\neth0: ipv6_start: Permission denied\neth0: soliciting a DHCP lease\neth0: offered 192.168.1.XXX from 192.168.1.XXX\neth0: probing address 192.168.1.XXX/24\neth0: leased 192.168.1.XXX for infinity\ndhcp_writefile: /var/lib/dhcpcd/eth0.lease: Permission denied\neth0: adding route to 192.168.1.0/24\neth0: adding default route via 192.168.1.XXX\nDropped protocol specifier '.dhcp' from 'eth0.dhcp'. Using 'eth0' (ifindex=2).\nsd_bus_open_system: No such file or directory\nmkdir: cannot create directory '/var/lib/ntp': Permission denied\n" }
[2024-11-21T23:40:08Z DEBUG muvm::guest::sommelier] exec command="/usr/local/bin/muvm-server" command_args=["FEXBash"]

dhcpcd wants to create /var/lib/ntp and connect to systemd via sd_bus_open_system(), which both fails.
I'm not sure if that's actually the reason why /etc/resolv.conf is not updated.

However, muvm is installing an empty /etc/resolv.conf during VM startup in https://github.com/AsahiLinux/muvm/blob/main/crates/muvm/src/guest/mount.rs#L142 . I guess it's expected that the DHCP client overwrites this file afterwards.

As a workaround, we can also populate the file during creation already:

diff --git a/crates/muvm/src/guest/mount.rs b/crates/muvm/src/guest/mount.rs
index a816b3c..78e8f68 100644
--- a/crates/muvm/src/guest/mount.rs
+++ b/crates/muvm/src/guest/mount.rs
@@ -138,7 +138,7 @@ pub fn mount_filesystems() -> Result<()> {
         println!("Failed to mount FEX rootfs, carrying on without.")
     }
 
-    place_etc("resolv.conf", None)?;
+    place_etc("resolv.conf", Some("nameserver 9.9.9.9\n"))?;
 
     mount2(
         Some("binfmt_misc"),

This provides working DNS resolution without any other configuration in the root FS.

[teohhanhui]

I think it's fine to add that workaround (but with 1.1.1.1), provided dhclient / dhcpcd correctly overwrites it.

PR welcome.

[kaazoo]

Please see PR here: #110