Installer implemented in the live CD! However we still need to add some old realtek network card support for r1

This commit is contained in:
markmental 2026-09-10 20:22:38 -04:00
commit 1d86d4f1f9
4 changed files with 497 additions and 4 deletions

18
.config
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@ -1,6 +1,6 @@
# #
# Automatically generated file; DO NOT EDIT. # Automatically generated file; DO NOT EDIT.
# Buildroot -g430ecb4-dirty Configuration # Buildroot -g0d30096-dirty Configuration
# #
BR2_HAVE_DOT_CONFIG=y BR2_HAVE_DOT_CONFIG=y
BR2_HOST_GCC_AT_LEAST_4_9=y BR2_HOST_GCC_AT_LEAST_4_9=y
@ -914,7 +914,17 @@ BR2_PACKAGE_MAKE=y
# BR2_PACKAGE_DAVFS2 is not set # BR2_PACKAGE_DAVFS2 is not set
# BR2_PACKAGE_DOSFSTOOLS is not set # BR2_PACKAGE_DOSFSTOOLS is not set
# BR2_PACKAGE_DUST is not set # BR2_PACKAGE_DUST is not set
# BR2_PACKAGE_E2FSPROGS is not set BR2_PACKAGE_E2FSPROGS=y
# BR2_PACKAGE_E2FSPROGS_DEBUGFS is not set
# BR2_PACKAGE_E2FSPROGS_E2IMAGE is not set
#
# e2scrub needs bash, coreutils, lvm2, and util-linux
#
# BR2_PACKAGE_E2FSPROGS_E4DEFRAG is not set
BR2_PACKAGE_E2FSPROGS_FSCK=y
# BR2_PACKAGE_E2FSPROGS_FUSE2FS is not set
# BR2_PACKAGE_E2FSPROGS_RESIZE2FS is not set
# BR2_PACKAGE_E2TOOLS is not set # BR2_PACKAGE_E2TOOLS is not set
# BR2_PACKAGE_ECRYPTFS_UTILS is not set # BR2_PACKAGE_ECRYPTFS_UTILS is not set
# BR2_PACKAGE_EROFS_UTILS is not set # BR2_PACKAGE_EROFS_UTILS is not set
@ -4565,7 +4575,7 @@ BR2_PACKAGE_SYSTEMD_BOOTCHART_ARCH_SUPPORTS=y
# BR2_PACKAGE_TPM2_TOTP is not set # BR2_PACKAGE_TPM2_TOTP is not set
# BR2_PACKAGE_UNSCD is not set # BR2_PACKAGE_UNSCD is not set
BR2_PACKAGE_UTIL_LINUX=y BR2_PACKAGE_UTIL_LINUX=y
# BR2_PACKAGE_UTIL_LINUX_LIBBLKID is not set BR2_PACKAGE_UTIL_LINUX_LIBBLKID=y
# BR2_PACKAGE_UTIL_LINUX_LIBFDISK is not set # BR2_PACKAGE_UTIL_LINUX_LIBFDISK is not set
# BR2_PACKAGE_UTIL_LINUX_LIBMOUNT is not set # BR2_PACKAGE_UTIL_LINUX_LIBMOUNT is not set
# BR2_PACKAGE_UTIL_LINUX_LIBSMARTCOLS is not set # BR2_PACKAGE_UTIL_LINUX_LIBSMARTCOLS is not set
@ -4713,7 +4723,7 @@ BR2_TARGET_GRUB2_I386_PC=y
BR2_TARGET_GRUB2_BOOT_PARTITION="hd0,msdos1" BR2_TARGET_GRUB2_BOOT_PARTITION="hd0,msdos1"
BR2_TARGET_GRUB2_BUILTIN_MODULES_PC="boot linux ext2 fat squash4 part_msdos part_gpt normal biosdisk iso9660 search search_fs_file" BR2_TARGET_GRUB2_BUILTIN_MODULES_PC="boot linux ext2 fat squash4 part_msdos part_gpt normal biosdisk iso9660 search search_fs_file"
BR2_TARGET_GRUB2_BUILTIN_CONFIG_PC="board/mentalnet/grub-embedded.cfg" BR2_TARGET_GRUB2_BUILTIN_CONFIG_PC="board/mentalnet/grub-embedded.cfg"
# BR2_TARGET_GRUB2_INSTALL_TOOLS is not set BR2_TARGET_GRUB2_INSTALL_TOOLS=y
BR2_PACKAGE_SHIM_ARCH_SUPPORTS=y BR2_PACKAGE_SHIM_ARCH_SUPPORTS=y
# BR2_TARGET_SHIM is not set # BR2_TARGET_SHIM is not set
# BR2_TARGET_SYSLINUX is not set # BR2_TARGET_SYSLINUX is not set

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# Mentalnet GNU/Linux — Install & Test Guide
Mentalnet GNU/Linux is a small, TTY-only distribution for 90s Intel
Pentium-class PCs, built with Buildroot 2025.02.17. The ISO is a live
CD: the entire system runs from the CD with a read-only root, and the
same CD carries a built-in hard disk installer (`mentalnet-install`).
- Kernel: `6.12.104-mentalnet-intel32` (slimmed i386 config)
- Login: `root` / `mnlinux`
- Hostname: `mentalnet`
- Live CD size: ~100 MB
---
## 1. System requirements
### Running the live CD
| Component | Requirement |
|-------------|----------------------------------------------------------|
| CPU | i586 (generic Pentium) or any newer x86 |
| RAM | 128 MB minimum (64 MB usually works) |
| CD drive | IDE/ATAPI CD-ROM (PIIX-era ATA controller) |
| Display | VGA text console, PS/2 keyboard/mouse |
| USB | USB keyboards, mice and mass storage (UHCI/OHCI/EHCI) |
| Serial | 8250 UART (kernel log is mirrored to COM1) |
| NICs (opt.) | NE2000-PCI clones (RTL8029 etc.), Intel e100/e1000/e1000e, Realtek 8139, 3Com 3c59x |
### Installing to a hard disk
- IDE/ATA disk with at least **400 MB** free (the whole disk is wiped)
- The machine must be able to boot from CD (El Torito, BIOS boot)
---
## 2. What's on the media
The live system mounts its root filesystem **read-only** from the CD.
Everything writable lives in RAM:
- `/tmp`, `/run`, `/dev/shm` are tmpfs
- `/var/log`, `/var/run`, `/var/cache`, `/var/spool`, `/var/tmp`
are symlinks into those tmpfs areas
Services started at boot:
| Service | Purpose |
|------------|------------------------------------------------|
| DHCP | `eth0` configured via udhcpc |
| syslogd | kernel + system logging (to `/tmp/log`) |
| lighttpd | web server, port 80 |
| dropbear | SSH server, port 22 |
| chronyd | NTP time sync |
| crond | cron daemon |
| iptables | firewall rules |
DNS from DHCP works on the live CD too: `/etc/resolv.conf` is a
symlink into tmpfs that `udhcpc` writes through.
---
## 3. Building from source
The build tree is a standard Buildroot 2025.02.17 checkout with the
Mentalnet configuration applied. Install the usual Buildroot host
dependencies (see `docs/manual/prerequisite.txt` in the Buildroot
manual), then:
```
make
```
Build outputs land in `output/images/`:
| File | Purpose |
|-------------------|--------------------------------------------------|
| `rootfs.iso9660` | the bootable live CD / installer ISO |
| `bzImage` | the kernel (also inside the ISO and ext2 image) |
| `rootfs.ext2` | 2 GB raw disk image variant (for QEMU testing) |
| `grub-eltorito.img` / `grub.img` | GRUB core images (used by the ISO) |
A full build takes a while; rebuilds after config changes are much
faster. After editing kernel fragments or the overlay, plain `make`
picks the changes up.
---
## 4. Testing in QEMU
All commands are run from the Buildroot tree root. Exit a
`-nographic` session with `Ctrl-A x`.
### 4.1 Live CD, graphical window
```
qemu-system-i386 -m 128 -cdrom output/images/rootfs.iso9660
```
Expect the GRUB menu ("Mentalnet GNU/Linux", 10s timeout), a kernel
boot and a login prompt on the VGA console.
### 4.2 Headless (serial console)
```
qemu-system-i386 -m 128 -nographic \
-kernel output/images/bzImage \
-append "console=ttyS0 root=/dev/sr0 ro" \
-cdrom output/images/rootfs.iso9660
```
This bypasses GRUB and shows the whole boot on the terminal.
### 4.3 Low-memory margin test
Same as 4.2 but with `-m 64`. The live system should still come up.
### 4.4 NE2000 network test
```
qemu-system-i386 -m 128 -nographic -nic model=ne2k_pci \
-kernel output/images/bzImage \
-append "console=ttyS0 root=/dev/sr0 ro" \
-cdrom output/images/rootfs.iso9660
```
After login, `ip link` should show a configured `eth0`.
### 4.5 Disk image variant
```
qemu-system-i386 -m 128 -nographic \
-kernel output/images/bzImage \
-append "console=ttyS0 root=/dev/sda1 rootwait rw" \
-drive file=output/images/rootfs.ext2,format=raw,if=ide
```
(`rootfs.ext2` also contains `/boot/bzImage` and a GRUB config for
disk boot.)
### 4.6 Full installer end-to-end test
```
# 1. create a throwaway disk
qemu-img create -f qcow2 /tmp/mn-test.qcow2 512M
# 2. boot the live CD with the test disk attached
qemu-system-i386 -m 128 -nographic \
-kernel output/images/bzImage \
-append "console=ttyS0 root=/dev/sr0 ro" \
-cdrom output/images/rootfs.iso9660 \
-drive file=/tmp/mn-test.qcow2,format=qcow2,if=ide
```
Log in and run `mentalnet-install`:
```
Disk to install to (e.g. sda): sda
Type YES to continue: YES
Create a swap partition? [y/N]: y
```
When it prints `Installation complete!`:
```
poweroff
```
Then boot **only** the test disk (no `-cdrom`, no `-kernel`) — this
exercises the installed GRUB in the MBR:
```
qemu-system-i386 -m 128 -nographic \
-drive file=/tmp/mn-test.qcow2,format=qcow2,if=ide
```
The kernel log (mirrored to the serial console by the installed
config) should show `EXT4-fs (sda1): mounted ... r/w` and
`Run /sbin/init as init process`.
---
## 5. Installing to a hard disk (real hardware)
> **WARNING: the installer destroys ALL data on the target disk
> without further notice.** Double-check the disk name before
> confirming.
1. Boot the machine from the CD (El Torito boot).
2. Log in as `root` (password `mnlinux`).
3. Run:
```
mentalnet-install
```
4. Answer the prompts:
- **Disk to install to** — e.g. `sda` (the installer lists
detected disks with their sizes first)
- **Type YES** — destroys everything on that disk
- **Create a swap partition? [y/N]** — recommended on machines
with little RAM; the swap is sized at 2x RAM, capped at 512 MB
5. The installer then:
- writes a fresh MBR partition table (root partition starts at
sector 2048, leaving room for the GRUB core image)
- creates an ext4 filesystem labelled `rootfs` (+ swap if chosen)
- copies the whole system from the CD
- generates `/etc/fstab`
- installs GRUB to the MBR and writes the boot menu
6. When it prints `Installation complete!`:
```
poweroff
```
Remove the CD and power on — the machine now boots from its own
disk.
The installed GRUB menu has a 5s timeout and boots automatically.
---
## 6. Post-install notes
- The installed root filesystem is **read-write**, so all services
behave normally: chrony keeps its drift file, dropbear generates
SSH host keys on first boot, logs persist under `/var/log`.
- DHCP DNS works the same way as on the live CD (`resolv.conf`
symlink into tmpfs).
- Kernel boot messages are mirrored to `COM1` (ttyS0) — handy for
debugging headless or semi-broken machines.
- Login is `root` / `mnlinux` (same as the live system).
---
## 7. Troubleshooting
| Symptom | Likely cause / fix |
|---------|--------------------|
| GRUB menu does not appear, or the machine reboots before booting, in QEMU | Try more RAM (`-m 256`). Memory pressure during development was the culprit more than once. |
| Kernel panic: `Unable to mount root fs` | The CD drive is on an unsupported controller. The kernel targets PIIX-era IDE/ATA; modern SATA-only setups are out of scope. |
| `Remounting root filesystem read-write ... failed` on live boot | Cosmetic. The CD root is read-only by design; all writes go to tmpfs. |
| Installer: `/dev/sdX1 did not appear after partitioning` | The kernel was still re-reading the partition table. Simply run the installer again. |
| Installer: `disk is too small` | At least 400 MB is needed. |
| Forgot the password | It is `mnlinux` (set at build time in the Buildroot config). |
| No network | Check the NIC against the supported list in section 1. QEMU: use `-nic model=ne2k_pci` or the default e1000. |
---
## 8. Maintainer file map
Everything Mentalnet-specific lives here:
| File | Purpose |
|------|---------|
| `board/mentalnet/grub-embedded.cfg` | config embedded into the GRUB core image: searches for the medium containing `/boot/bzImage` instead of hardcoding a device |
| `board/mentalnet/linux-slim.config` | kernel config fragment: keeps the classic PCI NICs, ATA/ATAPI, USB HID/storage, serial and VGA console; drops wireless, sound, DRM, RAID, PCMCIA, debug |
| `board/mentalnet/overlay/usr/sbin/mentalnet-install` | the hard disk installer |
| `board/mentalnet/overlay/usr/share/mentalnet/grub-disk.cfg` | boot menu template written to installed systems (`@ROOTDEV@` is replaced) |
| `board/mentalnet/overlay/etc/resolv.conf` | symlink so DHCP DNS works on the read-only CD |
| `board/mentalnet/overlay/etc/lighttpd/` | web server configuration |
| `fs/iso9660/grub.cfg` | live CD boot menu (`root=/dev/sr0 ro`) |
| `localversion.config` | kernel version suffix (`-mentalnet-intel32`) |
| `.config` | Buildroot configuration: GRUB2 embedded config path and module list, kernel fragment list, e2fsprogs/grub install tools |

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#!/bin/sh
#
# mentalnet-install - install Mentalnet GNU/Linux from the live CD onto a hard disk
#
# Run as root on the live system: mentalnet-install
#
# The installed system boots from its own MBR (GRUB) with the root
# filesystem on a single ext4 partition (plus optional swap).
set -u
MIN_DISK_SECTORS=819200 # 400 MiB minimum target disk
BOOT_START_SECTORS=2048 # first sector of root: leaves the MBR gap
# free for the GRUB core.img embedding
MNT=/mnt/hd
msg() { printf '%s\n' "$*"; }
warn() { printf 'WARNING: %s\n' "$*"; }
die() { printf 'ERROR: %s\n' "$*" >&2; exit 1; }
# make sure a failed run never leaves the target disk mounted
cleanup() {
grep -q " $MNT " /proc/mounts 2>/dev/null && umount "$MNT" 2>/dev/null
[ -n "${TMNT:-}" ] && umount /mnt 2>/dev/null
return 0
}
trap cleanup EXIT
[ "$(id -u)" -eq 0 ] || die "please run as root"
for t in fdisk mkfs.ext4 mkswap grub-install; do
command -v "$t" >/dev/null 2>&1 || die "required tool '$t' not found"
done
banner() {
clear 2>/dev/null
msg ""
msg " ============================================================"
msg " Mentalnet GNU/Linux - hard disk installer"
msg " ============================================================"
msg ""
msg " This will copy the live system from the CD onto a local"
msg " disk, install the GRUB bootloader, and make the disk"
msg " bootable on its own."
msg ""
}
list_disks() {
for d in /sys/block/*; do
dev=${d##*/}
case "$dev" in
sr*|loop*|ram*|zram*|md*|dm-*|fd*|nbd*) continue ;;
esac
size=$(cat "$d/size" 2>/dev/null) || continue
mib=$((size / 2048))
model=$(cat "$d/device/model" 2>/dev/null | tr -d ' ')
printf ' /dev/%-6s %6s MiB %s\n' "$dev" "$mib" "${model:-}"
done
}
banner
msg " Detected disks:"
list_disks
msg ""
printf ' Disk to install to (e.g. sda): '
read -r DISK
[ -n "${DISK:-}" ] || die "no disk given"
case "$DISK" in
sr*|loop*|ram*|zram*|md*|dm-*|fd*|nbd*) die "refusing to use $DISK" ;;
*[!/a-z0-9]*) die "invalid disk name" ;;
esac
DEV="/dev/$DISK"
SYS="/sys/block/$DISK"
[ -d "$SYS" ] && [ -b "$DEV" ] || die "$DEV is not a block device"
SIZE=$(cat "$SYS/size")
[ "$SIZE" -ge "$MIN_DISK_SECTORS" ] \
|| die "$DEV is too small (need $((MIN_DISK_SECTORS / 2048)) MiB minimum)"
if grep -q "^$DEV" /proc/mounts; then
die "$DEV (or a partition on it) is currently mounted"
fi
msg ""
warn "ALL DATA on $DEV will be DESTROYED without further notice."
printf ' Type YES to continue: '
read -r ANSWER
[ "${ANSWER:-}" = "YES" ] || { msg "Aborted."; exit 0; }
# --- swap? ---------------------------------------------------------------
printf ' Create a swap partition? [y/N]: '
read -r SWAPANS
SWAP=0
case "${SWAPANS:-}" in
y|Y|yes|Yes|YES) SWAP=1 ;;
esac
SWAP_SECTORS=0
if [ "$SWAP" -eq 1 ]; then
MEM_KB=$(awk '/^MemTotal:/{print $2}' /proc/meminfo)
SWAP_MIB=$((MEM_KB / 1024 * 2))
[ "$SWAP_MIB" -gt 512 ] && SWAP_MIB=512
[ "$SWAP_MIB" -lt 32 ] && SWAP_MIB=32
SWAP_SECTORS=$((SWAP_MIB * 2048))
msg " Swap partition: ${SWAP_MIB} MiB"
fi
# --- partition -----------------------------------------------------------
msg " Partitioning $DEV (MBR, root at sector $BOOT_START_SECTORS) ..."
if [ "$SWAP" -eq 1 ]; then
P1_END=$((SIZE - SWAP_SECTORS - 1))
P2_START=$((SIZE - SWAP_SECTORS))
printf 'o\nn\np\n1\n%d\n%d\nn\np\n2\n%d\n%d\nt\n2\n82\na\n1\nw\n' \
"$BOOT_START_SECTORS" "$P1_END" \
"$P2_START" "$((SIZE - 1))" \
| fdisk -u "$DEV" >/dev/null || die "fdisk failed"
else
printf 'o\nn\np\n1\n%d\n%d\na\nw\n' \
"$BOOT_START_SECTORS" "$((SIZE - 1))" \
| fdisk -u "$DEV" >/dev/null || die "fdisk failed"
fi
ROOTPART="${DEV}1"
i=0
while [ ! -b "$ROOTPART" ] && [ "$i" -lt 10 ]; do
i=$((i + 1))
partprobe "$DEV" 2>/dev/null
sleep 1
done
[ -b "$ROOTPART" ] || die "$ROOTPART did not appear after partitioning"
# --- filesystems ---------------------------------------------------------
msg " Creating ext4 filesystem on $ROOTPART ..."
mkfs.ext4 -F -L rootfs "$ROOTPART" >/dev/null || die "mkfs.ext4 failed"
if [ "$SWAP" -eq 1 ]; then
msg " Creating swap on ${DEV}2 ..."
mkswap "${DEV}2" >/dev/null || die "mkswap failed"
fi
# --- copy the live system ------------------------------------------------
# /mnt lives on the read-only CD, so put a writable tmpfs over it to
# get a usable mount point
TMNT=
if ! grep -q ' /mnt ' /proc/mounts; then
mount -t tmpfs -o mode=0755 tmpfs /mnt || die "cannot set up /mnt"
TMNT=1
fi
mkdir -p "$MNT"
mount -t ext4 "$ROOTPART" "$MNT" || die "could not mount $ROOTPART"
msg " Copying the system (this takes a while) ..."
# NOTE: one single tar invocation per side. busybox tar stops reading at
# the first end-of-archive marker, so piping several archives through
# '-' would silently transfer only the first directory.
DIRS=
for d in bin boot etc home lib lib32 lib64 media opt root sbin srv usr var; do
[ -e "/$d" ] && DIRS="$DIRS $d"
done
(cd / && tar -cf - $DIRS) | (cd "$MNT" && tar -xpf -) \
|| die "copying failed"
# mount points that live in tmpfs on the CD
mkdir -p "$MNT/proc" "$MNT/sys" "$MNT/dev" "$MNT/tmp" "$MNT/run" "$MNT/mnt"
# CD-only artifacts must not end up on the disk
rm -f "$MNT/boot/grub/grub-eltorito.img"
# --- /etc/fstab ----------------------------------------------------------
msg " Writing /etc/fstab ..."
cat > "$MNT/etc/fstab" <<EOF
# /etc/fstab - generated by mentalnet-install
$ROOTPART / ext4 rw,noatime 0 1
proc /proc proc defaults 0 0
devpts /dev/pts devpts defaults,gid=5,mode=620,ptmxmode=0666 0 0
tmpfs /dev/shm tmpfs mode=1777 0 0
tmpfs /tmp tmpfs mode=1777 0 0
tmpfs /run tmpfs mode=0755,nosuid,nodev 0 0
sysfs /sys sysfs defaults 0 0
EOF
if [ "$SWAP" -eq 1 ]; then
printf '%s none swap sw 0 0\n' "${DEV}2" >> "$MNT/etc/fstab"
fi
# --- bootloader ----------------------------------------------------------
msg " Writing bootloader configuration ..."
sed "s|@ROOTDEV@|$ROOTPART|" /usr/share/mentalnet/grub-disk.cfg \
> "$MNT/boot/grub/grub.cfg" \
|| die "could not write grub.cfg"
msg " Installing GRUB to the MBR of $DEV ..."
grub-install --boot-directory="$MNT/boot" "$DEV" >/dev/null 2>&1 \
|| die "grub-install failed"
sync
umount "$MNT" || umount -f "$MNT" || die "could not unmount $MNT"
[ -n "$TMNT" ] && umount /mnt
msg ""
msg " ============================================================"
msg " Installation complete!"
msg " ============================================================"
msg ""
msg " Root partition : $ROOTPART (ext4)"
[ "$SWAP" -eq 1 ] && msg " Swap : ${DEV}2 (${SWAP_MIB} MiB)"
msg " Login : root / mnlinux"
msg ""
msg " Remove the CD and reboot: poweroff"
msg ""

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set default="0"
set timeout="5"
menuentry "Mentalnet GNU/Linux" {
linux /boot/bzImage root=@ROOTDEV@ rootwait rw console=ttyS0,9600n8 console=tty0
}