UEFI firmware does not have to be able to read ISO9660 filesystems, so
the El Torito mechanism provides a way to specify an embedded FAT32
image which contains files the UEFI firmware itself must be able to
read, such as UEFI executables. Once GRUB starts and reads its
configuration, it can access the ISO9660 filesystem to load other files.
This change removes the unused kernel, initrd, and GRUB font files from
the El Torito image, but keeps the GRUB configuration and UEFI
executables. These files have been present since EFI support was
originally introduced in commit 097c656. Other distribution ISOs, such
as Ubuntu 20.04, Fedora 35, and Windows 10 work this way too. This saves
24MiB on x86_64 and 61MiB on aarch64 ISOs.
so the underlaying use case of the preceding commit is so
generic, that we gain a lot in reasoning to give it an
appropriate name.
As the comment states:
image media needs to override host config short of mkForce
https://github.com/NixOS/nixpkgs/pull/131760 was made to avo
a speicific configuration conflict that errored out for multiple definitions of "/" when the installer where overlayed
on any existing host configuration.
---
Problem 1: It turns out that in also other mountpoints can coflict.
Solution 1: use `mkOverride 60` for all mountpoints (even for the ones unlikely causing confilct for consistency sake)
---
Problem 2: It turns out that on an installation media for a fresh machine (before formatting), we usually don't have any devices yet formatted. However defining for example `fileSystems.<nme>.device = "/dev/disk/by-label/...", in newer versions of nixos, seems to make the system startup fail. Similarily waiting for a non-existent swap device does not make the startup fail, but has a 1:30 min timeout.
Solution 2: For an installation medium, soft-override ("unless users know what they are doing") the entire `fileSystems` and `swapDevices` definitions.
installer media can be used on top of existing host configs. In such
scenarions, root fs types will already be defined.
Before this change, this will inevitably lead to the following error:
```console
error: The option `fileSystems./.fsType' has conflicting definition values:
- In `/nix/store/2nl5cl4mf6vnldpbxhrbzfh0n8rsv9fm-source/DevOS/os/hardware/common.nix': "ext4"
- In `/nix/store/jbch90yqx6gg1h3fq30jjj2b6h6jfjgs-source/nixos/modules/installer/cd-dvd/iso-image.nix': "tmpfs"
```
With this patch, the installers will override those values according to
their own local requirement.
Use `mkOverride 60` so that conscientious overriding specially targeted
at the installer, e.g. with `mkForce` is still straight forward.
This should help in rare hardware-specific situations where the root is
not automatically detected properly.
We search using a marker file. This should help some weird UEFI setups
where the root is set to `(hd0,msdos2)` by default.
Defaulting to `(hd0)` by looking for the ESP **will break themeing**. It
is unclear why, but files in `(hd0,msdos2)` are not all present as they
should be.
This also fixes an issue introduced with cb5c4fcd3c
where rEFInd stopped booting in many cases. This is because it ended up
using (hd0) rather than using the `search` which was happening
beforehand, which in turn uses (hd0,msdos2), which is the ESP.
Putting back the `search` here fixes that.
This technically changes nothing. In practice `$root` is always the
"CWD", whether searched for automatically or not.
But this serves to announce we are relying on `$root`... I guess...
The value of du output depends on the underlying file system, and thus is not fully deterministic. This workaround rounds up the disk usage size to the nearest multiple of 1MB, to increase the probability that two du output values on two different file systems fall within the same 1MB window. Note that this workaround won't make du output 100% reproducible, but will increase the probability of getting deterministic builds across different file systems.
mcopy file globbing is non-deterministic with respect to the underlying file
system. As a result, the current mcopy approach is less likely to reproduce
efi.img on different machines. We replace mcopy file globbing with
fixed-order mmd and mcopy operations for better determinism. We also use
faketime on mmd for the same reason. We use faketime, mmd, and mcopy
directly, becase they are already in PATH.
Thank misuzu@ for the feedback.
Looks like GRUB has issues loading EFI binaries from (cd0), which is
what would be used in e.g. qemu with OVMF with `-cdrom`. Apparently also
what is used with AArch64 + U-Boot USB.
The serial output (but it's named console, not serial actually) causes
issues on U-Boot's EFI, at the very least.
This is inspired by OpenSUSE's approach:
* https://build.opensuse.org/package/view_file/Base:System/grub2/grub2-SUSE-Add-the-t-hotkey.patch
Where they add a hidden menu entry, which can be used to force the
console output.
The `echo` will be visible on the serial terminal (grub "console"),
while the graphical interface is shown. Note that input in the serial
terminal (grub "console") will continue controlling the graphical
interface. Useful if you have an SBC connectedinto an HDMI monitor, but
no keyboard connected to it.
Minimal ISO:
1m21 -> 2m25
625M -> 617M
Plasma5 ISO:
2m45 -> 5m18
1.4G -> 1.3G
Decompression speed stays about the same. It's just a few seconds for the whole
image anyways and, with that kind of speed, you're going to be bottlenecked by
IO long before the CPU.
Prior to this commit, installation over serial console would requiring
manually having to modify the kernel modeline, as described in
https://github.com/NixOS/nixpkgs/issues/58198 .
This is unnecessarily fiddly, so this commit adds a syslinux boot
entry that has serial enabled.
GRUB already has a serial console entry:
2c07a0800a/nixos/modules/installer/cd-dvd/iso-image.nix (L311-L317)
Why 115200 bps? This is already used in other places, e.g. https://github.com/NixOS/nixpkgs/pull/58196
I tested this change by building the image, booting the image, and
observing the boot process over serial:
$ cd nixos/
$ nix-build -A config.system.build.isoImage -I nixos-config=modules/installer/cd-dvd/installation-cd-minimal.nix default.nix
$ sudo cp /nix/store/arcl702c3z8xlndlvnfplq9yhixjvs9k-nixos-20.09pre-git-x86_64-linux.iso/iso/nixos-20.09pre-git-x86_64-linux.iso /dev/sdb
$ picocom -b 115200 /dev/ttyUSB0
we use stdenv.hostPlatform.uname.processor, which I believe is just like
`uname -p`.
Example values:
```
(import <nixpkgs> { system = "x86_64-linux"; }).stdenv.hostPlatform.uname.processor
"x86_64"
(import <nixpkgs> { system = "aarch64-linux"; }).stdenv.hostPlatform.uname.processor
aarch64
(import <nixpkgs> { system = "armv7l-linux"; }).stdenv.hostPlatform.uname.processor
"armv7l"
```
The volumeID will now be in the format of:
nixos-$EDITON-$RELEASE-$ARCH
an example for the minimal image would look like:
nixos-minimal-20.09-x86-64-linux
In 87a19e9048 I merged staging-next into master using the GitHub gui as intended.
In ac241fb7a5 I merged master into staging-next for the next staging cycle, however, I accidentally pushed it to master.
Thinking this may cause trouble, I reverted it in 0be87c7979. This was however wrong, as it "removed" master.
This reverts commit 0be87c7979.
I merged master into staging-next but accidentally pushed it to master.
This should get us back to 87a19e9048.
This reverts commit ac241fb7a5, reversing
changes made to 76a439239e.
When 'grafting' '/nix/store/<hash>-loopback.cfg' from disk onto
'/boot/grub/loopback.cfg' on the iso, the parent 'grub' directory does not
exist yet. In this case it is automatically created and inherits its
attributes, including timestamp, from /nix/store.
This is correct/expected/intentional behavior of xorriso, but has the
undesired result of leaking the timestamps of /nix/store into the iso. For
this reason we put the loopback.cfg in a
'/nix/store/<hash>-loopback.cfg/grub/loopback.cfg' instead, so it will inherit
the attributes from the correctly-timestamped
'/nix/store/<hash>-loopback.cfg/grub' directory.
For the same reason we move '/EFI/boot/efi-background.png' down in the list
so it is grafted after its parent '/EFI/boot' directory is created with
the correct timestamp.
fixes#74944
Prior to this commit an installation over serial via syslinux would
involve:
1. setting bitrate to BIOS's bitrate (typically 115200)
2. setting bitrate to syslinux's bitrate (38400)
3. setting bitrate to stty's bitrate (115200)
By changing syslinux's bitrate to 115200, an installation over serial
is a smoother experience, and consistent with the GRUB2 installation
which is also 115200 bps.
[root@nixos:~]# stty
speed 115200 baud; line = 0;
-brkint ixoff iutf8
-iexten
In a future commit I will add default serial terminals to the syslinux
kernel lines.
```
b Batch mode. Optimized for huge recursive copies, but less secure if a crash happens during the copy.
```
It seems the "less secure if a crash happens" does not need a crash to
happen.
With batch mode:
```
/[...]/.
Start (0) does not point to parent (___)
```
For pretty much everything copied in.
Without batch mode, everything passes `fsck`.
See #51150
Thomas Watson