update readme

This commit adds the requirement for a new kernel command line file at
`/etc/snap-pac-uki/kernel-cmd-current`. When generating current ukis, this file
will be used for the non-fallback variant instead of the generic `kernel-cmd`.

The reason for this change is hibernating. When saving the system state to RAM,
users might not want snapshot varints to resume from there. Previosly, this
would not have been a possible configuration.

README.md

@@ -13,17 +13,17 @@ required (though the name remains).
 
 ### Prerequisites
 
-This tool expects that you already set up snapper. It also expects that each
-snapshots linux and initramfs files (`/boot/vmlinuz-linux` and
-`/boot/initramfs-linux.img`) as well as a kernel command line file
-(`/etc/snap-pac-uki/kernel-cmd`) are available within each snapshot.
+While not depending on it directly, this tool expects that you already set up
+snapper. It expects, that each snapshot contains its kernel
+(`/boot/vmlinuz-linux`) and initramfs (`/boot/intitramfs-linux.img`), as well as
+a kernel command line file (`/etc/snap-pac-uki/kernel-cmd`).
 
-The fallback initramfs (`/boot/initramfs-linux-fallback.img`) and fallback
-command line file (`/etc/snap-pac-uki/kernel-cmd-fallback`) are only required
-on the current system.
+For generating the current and fallback UKIs, the kernel and initramfs files of
+the currently running system are used. For a kernel cmd, it uses
+`/etc/snap-pac-uki/kernel-cmd-current` and `/etc/snap-pac-uki/kernel-cmd-fallback`.
 
-EFI boot options are only created for each snapshot. If you want the UKIs
-created for the current system, you'll need to add boot entries yourself:
+If you want to boot a UKI directly, use the `efibootmgr` command to create an
+entry.
 
 ```bash
 # template
@@ -53,7 +53,7 @@ efibootmgr -c \
 1. You can install the dependencies of this program with the following command:
 
    ```bash
-   pacman -S fish efibootmgr jq ripgrep sbsigntools sed snapper
+   pacman -S fish ripgrep sbsigntools sed
    ```
 
 2. Download the latest release from [here][releases] and unpack it.

install.fish

@@ -8,8 +8,13 @@ if not test -d "/etc/snap-pac-uki"
     echo "created config dir."
 end
 
-cp ./src/config.fish /etc/snap-pac-uki/config.fish
-echo "installed config script."
+if not test -f "/etc/snap-pac-uki/config.fish"
+    cp ./src/config.fish /etc/snap-pac-uki/config.fish
+    echo "installed config script."
+else
+    cp ./src/config.fish /etc/snap-pac-uki/config-new.fish
+    echo "found existing config script -> installed as -new file."
+end
 
 cp ./pacman/* /usr/share/libalpm/hooks/
 echo "installed pacman hooks."

src/config.fish

@@ -1,5 +1,14 @@
 function config -d "sets some configuration variables"
 
+    # If this is not set to "yes", snap-pac-uki will not do anything when
+    # executed.
+    #
+    # This is to make sure that this program can be installed with pacman. If
+    # this wasn't done, pacman would install this program with an default
+    # config, which most likely wouldn't work correctly. Therefore this needs
+    # to be set to "yes" by the user, once they've configured snap-pac-uki.
+    set -g CFG_ENABLED "no"
+
     # A directory where ukis can be built.
     #
     # It is recommended to keep this within /tmp, as the generated data will not
@@ -12,18 +21,6 @@ function config -d "sets some configuration variables"
     # images.
     set -g CFG_DEFAULT_SUBVOL "@"
 
-    # The device the EFI partition resides on
-    set -g CFG_EFI_DEV "/dev/nvme0n1"
-
-    # The "efi directory" that will contain the ukis
-    set -g CFG_EFI_PATH "\EFI\Linux"
-
-    # The efi partitions number on the device
-    set -g CFG_EFI_PART "1"
-
-    # The snapper config name
-    set -g CFG_SNAPSHOT_CONFIG "root"
-
     # The linux fs path containing all snapshot data
     set -g CFG_SNAPSHOT_PATH "/.snapshots"
 

src/snap-pac-uki.fish

@@ -7,12 +7,8 @@ end
 
 function check_deps -d "checks if all dependencies are available"
     set -l dependencies \
-        "efibootmgr" \
-        "jq" \
         "rg" \
-        "sbsign" \
         "sed" \
-        "snapper" \
 
     for dep in $dependencies
         which $dep >/dev/null 2>/dev/null
@@ -21,13 +17,19 @@ function check_deps -d "checks if all dependencies are available"
             error "missing depenency: $dep"
         end
     end
+
+    which "sbsign" >/dev/null 2>/dev/null
+    if test $status != "0" -a $CFG_SECUREBOOT = "yes"
+        set -g CFG_SECUREBOOT "no"
+        echo "CFG_SECUREBOOT overwriten to \"no\": 'sbsign' not available"
+    end
 end
 
-function find_tasks -d "finds out what the program needs to do"
+function find_ukiless_snapshots -d "find"
     set -ge TASK_UKI
 
-    for id in (snapper -c $CFG_SNAPSHOT_CONFIG --jsonout ls | jq ".$CFG_SNAPSHOT_CONFIG [] | .number")
-        if test "$id" = "0"
+    for id in (ls $CFG_SNAPSHOT_PATH)
+        if test $id = "0"
             continue
         end
 
@@ -43,6 +45,7 @@ function create_uki -d "creates a new uki" -a variant id
     switch $variant
         case "rolling"
             set bd "$CFG_BUILD_DIR/current"
+            set current "-current"
         case "fallback"
             set bd "$CFG_BUILD_DIR/current"
             set fallback "-fallback"
@@ -54,12 +57,17 @@ function create_uki -d "creates a new uki" -a variant id
             error "unknown uki variant: $variant"
     end
 
+    # create initrd
+    set initrd "$bd/initramfs-linux$fallback.img"
+    cat "$prefix/boot/initramfs-linux$fallback.img" >> $initrd
+
+    # create uki
     objcopy \
         --add-section .osrel="$bd/os-release$fallback" --change-section-vma .osrel=0x20000 \
-        --add-section .cmdline="$bd/kernel-cmd$fallback" --change-section-vma .cmdline=0x30000 \
+        --add-section .cmdline="$bd/kernel-cmd$current$fallback" --change-section-vma .cmdline=0x30000 \
         --add-section .splash="$prefix/usr/share/systemd/bootctl/splash-arch.bmp" --change-section-vma .splash=0x40000 \
         --add-section .linux="$prefix/boot/vmlinuz-linux" --change-section-vma .linux=0x2000000 \
-        --add-section .initrd="$prefix/boot/initramfs-linux$fallback.img" --change-section-vma .initrd=0x3000000 \
+        --add-section .initrd="$initrd" --change-section-vma .initrd=0x3000000 \
         "$prefix/usr/lib/systemd/boot/efi/linuxx64.efi.stub" "$bd/arch-linux$fallback$snid.efi.unsigned"
 
     # sign
@@ -105,7 +113,7 @@ function create_current_uki -d "creates an uki for the current system"
 
     # create default
     cp "/usr/lib/os-release" "$bd/os-release"
-    sed "s/SNAPSHOT/$CFG_DEFAULT_SUBVOL/" <"/etc/snap-pac-uki/kernel-cmd" >"$bd/kernel-cmd"
+    sed "s/SNAPSHOT/$CFG_DEFAULT_SUBVOL/" <"/etc/snap-pac-uki/kernel-cmd-current" >"$bd/kernel-cmd-current"
     create_uki rolling
 
     # create fallbac
@@ -114,21 +122,21 @@ function create_current_uki -d "creates an uki for the current system"
     create_uki fallback
 end
 
-function add_efi_entry -d "adds an efi boot entry for a snapshot uki" -a id
-    efibootmgr -q -C -d $CFG_EFI_DEV -p $CFG_EFI_PART \
-        -l "$CFG_EFI_PATH\arch-linux-$id.efi" \
-        -L "Arch Linux (Snapshot $id)"
-end
-
 function main
     # prepare for execution
-    check_deps
     source "/etc/snap-pac-uki/config.fish"
     config
 
+    if test "$CFG_ENABLED" != "yes"
+        echo "==> snap-pac-uki not enabled in config file" 1>&2
+        exit 0
+    end
+
+    check_deps
+
     switch $argv[1]
         case "snapshots"
-            find_tasks
+            find_ukiless_snapshots
             for id in $TASK_UKI
                 echo "==> found snapshot without uki: $id"
 
@@ -137,9 +145,6 @@ function main
 
                 cp "$CFG_BUILD_DIR/$id/arch-linux-$id.efi" "$CFG_UKI_DIR"
                 echo "  -> copied uki for snapshot $id into uki directory"
-
-                add_efi_entry $id
-                echo "  -> created efi boot entry for uki of snapshot $id"
             end
 
         case "current"
@@ -155,13 +160,11 @@ function main
         case "clean"
             echo "==> cleaning ukis"
 
-            set ids (snapper -c $CFG_SNAPSHOT_CONFIG --jsonout ls | jq ".$CFG_SNAPSHOT_CONFIG [] | .number")
+            set ids (ls $CFG_SNAPSHOT_PATH)
             for uki in (ls "$CFG_UKI_DIR" | rg "[0-9]" | sed "s/arch-linux-\([0-9]*\).efi/\1/")
                 if not contains "$uki" $ids
                     echo "  -> cleaning uki and boot entry for removed snapshot $uki"
                     rm "$CFG_UKI_DIR/arch-linux-$uki.efi"
-
-                    efibootmgr -q -b (efibootmgr -v | rg "arch-linux-$uki.efi" | sed "s/\*//;s/Boot0*\(.*\) Arch .*/\1/") -B
                 end
             end
 

uninstall.fish

@@ -3,9 +3,6 @@
 rm /usr/local/bin/snap-pac-uki
 echo "removed script."
 
-rm /etc/snap-pac-uki/config.fish
-echo "removed config script."
-
 for name in (ls ./pacman)
     rm /usr/share/libalpm/hooks/$name
 end