Update docs

Assisted-by: GPT-5.6-Sol

Dockerfile

@@ -45,21 +45,16 @@ RUN sed -i 's/deb.debian.org/mirrors.ustc.edu.cn/g' /etc/apt/sources.list.d/debi
 RUN apt-get update && apt-get install -y \
         attr \
         bsdextrautils \
-        bzip2 \
         coreutils \
         dosfstools \
         e2fsprogs \
         fdisk \
         findutils \
-        gdisk \
-        gzip \
         libsqlite3-0 \
         mtools \
-        rsync \
         tar \
         util-linux \
         uuid-runtime \
-        xz-utils \
         zstd \
         zlib1g \
         policycoreutils \

README.md

@@ -34,11 +34,79 @@ It can be interrupted at any time, without harming your host OS.
 
 ## Prerequirements
 
-- Root-mode docker with `--priviledged` option available
-  - May not be necessary in the future
-- rsync
-- GNU Makefile
-- ~~And other basic shell utils~~
+- GNU Make 4 or newer
+- `rsync`, `curl`, and `unzip` for staging recipes and downloading blobs
+- RISC-V user-mode emulation and binfmt registration: `qemu-riscv64-static`
+  and `binfmt`; registration is a one-time system setup step
+- Docker or Podman; rootless operation is supported
+
+### Dependencies
+
+The Makefile uses these host commands before a build script runs:
+
+| Command | Debian package | Fedora package | Used for |
+| --- | --- | --- | --- |
+| `make` | `make` | `make` | Makefile target management |
+| `rsync` | `rsync` | `rsync` | Recipe staging |
+| `curl` | `curl` | `curl` | Remote blob downloads |
+| `unzip` | `unzip` | `unzip` | Extracting blob archives |
+| `qemu-riscv64-static` | `qemu-user-static` | `qemu-user-static` | Running RISC-V binaries on the build host |
+| `binfmt` registration | `binfmt-support` | `systemd` (`systemd-binfmt`) | Dispatching RISC-V binaries to QEMU |
+
+The build scripts and the recipe post-processing scripts use the following
+commands. The package names are the packages to install on the build host;
+some commands are also supplied by the default base image in Docker.
+
+| Command or tool | Debian package | Fedora package | Used for |
+| --- | --- | --- | --- |
+| `setfattr` | `attr` | `attr` | Removing the SELinux attribute from `/boot` |
+| `bash` | `bash` | `bash` | Running recipe scripts |
+| `column` | `bsdextrautils` | `util-linux` | Formatting generated `fstab` |
+| `coreutils` (`basename`, `cat`, `chmod`, `cp`, `cut`, `dd`, `du`, `head`, `ln`, `mkdir`, `mktemp`, `mv`, `readlink`, `rm`, `sha256sum`, `sort`, `stat`, `tee`, `tr`, `truncate`) | `coreutils` | `coreutils` | File, stream, and image operations |
+| `dosfstools` (`mkfs.vfat`) | `dosfstools` | `dosfstools` | Creating VFAT filesystems |
+| `e2fsprogs` (`mkfs.ext4`, `tune2fs`, `e2fsck`, `resize2fs`) | `e2fsprogs` | `e2fsprogs` | Creating and shrinking ext4 filesystems |
+| `find` | `findutils` | `findutils` | Finding and copying filesystem contents |
+| `grep` | `grep` | `grep` | Validation and command detection |
+| `hexdump` | `bsdextrautils` | `util-linux` | Generating VFAT UUIDs |
+| `mcopy`, `mlabel` | `mtools` | `mtools` | Writing and labeling VFAT images |
+| `blockdev`, `mount`, `umount`, `rev`, `seq`, `uuidgen` | `fdisk`, `util-linux`, `uuid-runtime` | `util-linux` | Mounting, partitioning, iteration, and UUIDs |
+| `policycoreutils` (`setfiles`) | `policycoreutils` | `policycoreutils` | Applying SELinux labels |
+| `rpm`/`dnf` (`yum`) | `rpm`, `dnf` | `rpm`, `dnf` | Installing packages into the rootfs |
+| `sed` | `sed` | `sed` | Parsing configuration and command output |
+| `tar` | `tar` | `tar` | Rootfs archive creation and extraction |
+| `zstd` | `zstd` | `zstd` | Rootfs compression |
+| `pseudo`, `pseudodb`, `pseudolog` | Build from source | Build from source | Rootfs ownership and metadata emulation |
+| `img2simg` | Build from source | Build from source | Optional sparse-image post-processing |
+
+For CI environments that invoke the scripts directly, install the dependencies
+with Debian:
+
+```shell
+sudo apt-get update
+sudo apt-get install --no-install-recommends \
+    attr bash bsdextrautils coreutils curl dosfstools e2fsprogs fdisk findutils \
+    grep make mtools policycoreutils qemu-user-static binfmt-support rsync rpm \
+    sed tar unzip util-linux uuid-runtime zstd
+sudo update-binfmts --enable qemu-riscv64
+```
+
+The corresponding Fedora setup is:
+
+```shell
+sudo dnf install \
+    attr bash coreutils curl dosfstools e2fsprogs findutils grep make mtools \
+    policycoreutils qemu-user-static rsync rpm sed tar unzip util-linux zstd
+sudo systemctl enable --now systemd-binfmt
+```
+
+`pseudo` and `img2simg` are built in the Dockerfile and are not standard
+runtime packages on Debian or Fedora. They must also be available in `PATH`
+when scripts are invoked directly.
+
+The current Dockerfile does not need `bzip2`, `gzip`, `xz-utils`, `gdisk`, or
+`rsync`: the scripts use Zstandard only, partitioning is done by `sfdisk`, and
+recipe staging, downloading, and extraction happen on the host. `zlib1g`
+remains required by the custom `img2simg` binary.
 
 ## Usage
 
@@ -52,7 +120,7 @@ Firstly, let it build a container image for later use:
 make container
 ```
 
-It will be tagged and managed by docker.
+It will be tagged and managed by the configured container runtime.
 
 Listing all available targets:
 
@@ -78,16 +146,20 @@ Build all available BSP targets, parallelly:
 make -j$(nproc) all_bsp
 ```
 
-To invoke `build_rootfs.sh` and `build_bsp.sh` directly on the host instead of
-through a container, clear `CONTAINER_CMD`:
+For CI jobs that invoke `build_rootfs.sh` and `build_bsp.sh` directly instead
+of through a container, clear `CONTAINER_CMD`:
 
 ```shell
 make CONTAINER_CMD= openEuler-24.03-LTS-SP4-RVA23-base-OLK-generic
 ```
 
-Direct execution requires the tools used by the scripts, including `pseudo`,
-`yum` or `dnf`, filesystem utilities, and sufficient privileges for mounting
-filesystems. `make container` still builds the Docker image.
+Normal builds use the configured container runtime. Set `CONTAINER_CMD=podman`
+to use Podman instead of Docker:
+
+```shell
+make CONTAINER_CMD=podman container
+make CONTAINER_CMD=podman openEuler-24.03-LTS-SP4-RVA23-base-OLK-generic
+```
 
 > BSP target will be rebuilt each time even if no configuration is changed