always install config.example if available

README.md

@@ -0,0 +1,315 @@
+# pbc
+
+A Bash wrapper around Proxmox's `proxmox-backup-client` for Proxmox Backup Server (PBS).
+
+It keeps the repository, credentials and the list of paths to back up in a single config
+file, injects the configured namespace (`--ns`) and encryption key (`--keyfile`) into every
+command that needs them, and lets you pick a snapshot group, snapshot and archive from an
+interactive menu instead of typing them out. Any command it does not implement itself is
+passed straight through to `proxmox-backup-client`.
+
+## Requirements
+
+- A Debian-based host with `bash` and `curl`
+- `jq` and `proxmox-backup-client` — both installed by `pbc install`
+- A reachable PBS with a datastore and an API token
+
+## Installation
+
+```bash
+curl -fsSL https://git.ccc-rheintal.ch/spacefreak/pbc/raw/branch/master/install.sh | sudo bash
+```
+
+This installs the newest tagged version to `/usr/local/bin/pbc`, installs the
+dependencies, and puts an example config at `/etc/pbc/config.example`.
+
+### Installing a specific version
+
+Set `PBC_GIT_TAG` to install that tag instead of the newest one:
+
+```bash
+curl -fsSL https://git.ccc-rheintal.ch/spacefreak/pbc/raw/branch/master/install.sh | sudo PBC_GIT_TAG=v1.0.0 bash
+```
+
+`sudo` drops the environment, so set the variable on the `sudo` command itself (or use
+`sudo -E`), not before `curl`. Any Git ref works, e.g. a branch name for testing.
+
+### Updating
+
+Run the same command again to update `pbc` itself:
+
+```bash
+curl -fsSL https://git.ccc-rheintal.ch/spacefreak/pbc/raw/branch/master/install.sh | sudo bash
+```
+
+It fetches the newest tag and overwrites `/usr/local/bin/pbc`. Your `/etc/pbc/config` is
+left untouched. `PBC_GIT_TAG` works here too, to pin or roll back to a given version.
+
+To update only the `proxmox-backup-client` binary:
+
+```bash
+sudo pbc install --update
+```
+
+This is skipped when the client is managed by the package manager — use `apt` in that case.
+
+## Configuration
+
+```bash
+sudo cp /etc/pbc/config.example /etc/pbc/config
+sudo chmod 640 /etc/pbc/config
+sudo editor /etc/pbc/config
+```
+
+| Key | Description |
+|---|---|
+| `PBS_SERVER` | PBS host and port |
+| `PBS_USER` | User and API token name, `user@realm:token-name` |
+| `PBS_PASSWORD` | The API token secret |
+| `PBS_DATASTORE` | Datastore to back up to |
+| `PBS_NAMESPACE` | Optional, namespace inside the datastore |
+| `BACKUP` | Array of `archive-name.pxar:/path` entries to back up |
+| `ENCRYPTION_KEYFILE` | Optional, path to the client encryption key — see [Encryption](#encryption) |
+| `PBC` | Optional, path to `proxmox-backup-client` (default `/usr/local/bin/proxmox-backup-client`) |
+
+`pbc` never creates the config for you — copy the example and edit it yourself. The file
+has to be readable for the user that runs `pbc`, so if that is not root, hand
+it over:
+
+```bash
+sudo chown youruser /etc/pbc/config
+```
+
+The config is sourced as Bash and contains your token secret. `pbc` refuses to run if the
+file is writable by group or others, and warns if it is readable by others.
+
+Check that it works:
+
+```bash
+pbc list
+```
+
+Use a different config with `-c`:
+
+```bash
+pbc -c ./myconfig list
+```
+
+## Encryption
+
+Backups can be encrypted client-side, so PBS only ever sees ciphertext. Create a key and
+point `ENCRYPTION_KEYFILE` at it:
+
+```bash
+sudo proxmox-backup-client key create /etc/pbc/backup.key --kdf none
+sudo chmod 600 /etc/pbc/backup.key
+```
+
+`pbc` errors out if the key is missing or unreadable, and warns if it is readable by
+others. As with the config, the file has to be readable for the user that runs `pbc` —
+`sudo chown youruser /etc/pbc/backup.key` if that is not root.
+
+**Back the key up somewhere else.** Without it the backups are unrecoverable, and a key
+stored only on the machine you are backing up is gone exactly when you need it. Print a
+recovery sheet and keep it off-host:
+
+```bash
+sudo proxmox-backup-client key paperkey /etc/pbc/backup.key
+```
+
+`--kdf none` leaves the key unprotected on disk, which is what makes unattended backups
+possible. With a passphrase-protected key (`--kdf scrypt`) the client prompts on every run
+and `backup-cron` hangs; export `PBS_ENCRYPTION_PASSWORD` in that case.
+
+The key is passed to `backup`, `backup-cron`, `mount` and `catalog-shell`. It is *not*
+passed to commands that fall through to `proxmox-backup-client` — `pbc restore` needs both
+flags spelled out:
+
+```bash
+pbc restore --ns MyBackups --keyfile /etc/pbc/backup.key \
+  host/myhost/2026-08-24T01:00:00Z root.pxar /mnt/restore
+```
+
+Setting `ENCRYPTION_KEYFILE` only affects snapshots made from then on. Older unencrypted
+snapshots stay readable, and listing works without the key either way — only reading
+archive contents needs it.
+
+## Usage
+
+Run `pbc --help` for the synopsis and the list of options, or `pbc -H` to additionally
+list every command of `proxmox-backup-client`. The commands `pbc` implements itself are
+described below.
+
+### backup
+
+Back up everything listed in `BACKUP` and print the client output:
+
+```bash
+pbc backup
+```
+
+Extra arguments are forwarded to the client:
+
+```bash
+pbc backup --exclude '/mnt/data/cache'
+```
+
+### backup-cron
+
+Same backup, but output is suppressed unless it fails — so cron only mails you on errors:
+
+```cron
+0 3 * * * /usr/local/bin/pbc backup-cron
+```
+
+### list
+
+List backup groups with their latest snapshot and archives:
+
+```bash
+pbc list
+```
+
+### snapshot-list
+
+List snapshots of a group with sizes and archives. Without an argument you get a menu of
+the available groups:
+
+```bash
+pbc snapshot-list
+pbc snapshot-list host/myhost
+```
+
+### mount
+
+Mount a single archive of a snapshot on a local directory. Anything you leave out is
+asked for interactively:
+
+```bash
+pbc mount
+pbc mount host/myhost/2026-08-24T01:00:00Z root.pxar /mnt/restore
+```
+
+The target directory is not created for you — create it beforehand and make sure it is
+writable for the user that runs `pbc`. Encrypted archives are decrypted transparently when
+`ENCRYPTION_KEYFILE` is configured. Unmount when done:
+
+```bash
+umount /mnt/restore
+```
+
+### catalog-shell
+
+Open an interactive shell to browse an archive and restore selected files — see below.
+Encrypted archives are decrypted transparently when `ENCRYPTION_KEYFILE` is configured.
+
+```bash
+pbc catalog-shell
+pbc catalog-shell host/myhost/2026-08-24T01:00:00Z root.pxar
+```
+
+### install
+
+Install or update the dependencies. Requires root:
+
+```bash
+sudo pbc install
+sudo pbc install --update
+```
+
+## Restoring files
+
+### Selectively, with `catalog-shell`
+
+```bash
+pbc catalog-shell
+```
+
+Pick a snapshot and an archive from the menu, then browse the archive as if it were a
+filesystem and mark what you want back:
+
+```
+pxar:/ > cd etc
+pxar:/etc > ls
+pxar:/etc > select hosts
+pxar:/etc > find etc/nginx/** --select
+pxar:/etc > list-selected
+pxar:/etc > restore-selected /mnt/restore
+pxar:/etc > exit
+```
+
+- `ls`, `cd`, `pwd`, `stat` — browse the archive
+- `select <path>` — mark a single file, relative to the current directory
+- `find <pattern> --select` — mark everything matching a glob
+- `deselect <path>` / `clear-selected` — drop one entry or all of them
+- `list-selected` — show what is currently marked
+- `restore-selected <target>` — restore only the marked entries
+- `restore <target> [pattern]` — restore the current directory and everything below it
+- `help` — list all available shell commands
+- `exit` — leave the shell
+
+#### Selecting a directory and everything beneath it
+
+`select` marks exactly the entry you give it and nothing else. Marking a directory
+therefore restores an empty directory — its contents are *not* included. Use a glob with
+`find --select` instead:
+
+```
+pxar:/ > find etc/nginx/** --select
+pxar:/ > select etc/nginx
+pxar:/ > restore-selected /mnt/restore
+```
+
+The `find` line picks up everything below `etc/nginx`; the `select` line adds the
+directory itself, so its own permissions and ownership are restored as well.
+
+Note that `find` patterns are always matched against paths relative to the archive root,
+no matter which directory you are in, and that `find` scans the whole archive — expect it
+to take a while on large backups.
+
+The target path must not exist yet; the restore creates it. Its parent directory has to be
+writable for the user that runs `pbc`.
+
+### Everything, or with normal tools
+
+To copy files out with `cp`, `rsync` or a file manager, mount the archive instead:
+
+```bash
+mkdir -p /mnt/restore     # must exist and be writable for the user running pbc
+pbc mount
+cp -a /mnt/restore/etc/nginx /etc/nginx
+umount /mnt/restore
+```
+
+## Running in WSL
+
+`pbc` also works inside a Debian-based WSL instance, which makes it a way to back up
+Windows directories: the Windows drives show up under `/mnt`, so they can be listed in
+`BACKUP` like any other path.
+
+```bash
+BACKUP=('users.pxar:/mnt/c/Users' 'projects.pxar:/mnt/d/projects')
+```
+
+A few things to keep in mind:
+
+- Access to files under `/mnt` is governed by Windows, not by the user you are inside the
+  WSL instance — `sudo` does not help there. To back up paths your Windows user cannot
+  read, start the WSL instance itself as administrator (run the terminal or `wsl.exe` via
+  *Run as administrator*), then run `pbc` in it.
+- The owner and permission metadata stored in the archive is the one WSL synthesizes for
+  Windows files, not the original Windows ACLs.
+- Cron is not running in a WSL instance by default, so `backup-cron` only fires if you
+  enable it — either by starting `cron` yourself, or by triggering `pbc backup-cron` from
+  the Windows Task Scheduler with `wsl.exe`:
+
+  ```
+  wsl.exe -d Debian -u root /usr/local/bin/pbc backup-cron
+  ```
+
+  For the reason above, such a task has to run with highest privileges to reach files that
+  are not accessible to your Windows user.
+
+## License
+
+GPLv3 — see [LICENSE](LICENSE).

config.example

@@ -3,5 +3,6 @@ PBS_USER='backup@pam:token-name'
 PBS_PASSWORD='XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX'
 PBS_DATASTORE='backup'
 PBS_NAMESPACE='MyBackups'
+#ENCRYPTION_KEYFILE='/etc/pbc/backup.key'
 
 BACKUP=('root.pxar:/' 'data.pxar:/mnt/data')

install.sh

@@ -13,7 +13,7 @@ function cleanup_work_dir() {
 function download_files() {
   local path rc
   local query_params=''
-  [ -n "$GIT_TAG" ] && query_params="?ref=$GIT_TAG"
+  [ -n "$PBC_GIT_TAG" ] && query_params="?ref=$PBC_GIT_TAG"
 
   while (( $# > 0 )); do
     path=$1
@@ -26,9 +26,9 @@ function download_files() {
   done
 }
 
-GIT_TAG=$(curl -fsSL "$API_ENDPOINT/tags" | grep -o '{"name":"[^"]*"' | sed 's/^{"name":"//;s/"$//' | sort --version-sort | tail -n 1)
+[ -z "$PBC_GIT_TAG" ] && PBC_GIT_TAG=$(curl -fsSL "$API_ENDPOINT/tags" | grep -o '{"name":"[^"]*"' | sed 's/^{"name":"//;s/"$//' | grep -E '^v[0-9]+' | sort --version-sort | tail -n 1)
-if [ -n "$GIT_TAG" ]; then
+if [ -n "$PBC_GIT_TAG" ]; then
-  echo "Info: installing pbc version $GIT_TAG"
+  echo "Info: installing pbc version $PBC_GIT_TAG"
 else
   echo "Warning: no Git tag found, installing from repository default branch" >&2
 fi

pbc

@@ -1,5 +1,7 @@
 #!/usr/bin/env bash
 
+set -o pipefail
+
 function usage() {
   local full=${1:-false}
   cat <<EOF
@@ -51,17 +53,17 @@ function pbc-version() {
   return $rc
 }
 
-function pbc-backup() { "$PBC" backup --ns "$PBS_NAMESPACE" "${BACKUP[@]}" "$@"; }
+function pbc-backup() { "$PBC" backup "${PBC_ARGS[@]}" "${KEY_ARGS[@]}" "${BACKUP[@]}" "$@"; }
 
-function pbc-list() { "$PBC" list --ns "$PBS_NAMESPACE" "$@"; }
+function pbc-list() { "$PBC" list "${PBC_ARGS[@]}" "$@"; }
 
-function pbc-snapshot-list() { "$PBC" snapshot list --ns "$PBS_NAMESPACE" "$@"; }
+function pbc-snapshot-list() { "$PBC" snapshot list "${PBC_ARGS[@]}" "$@"; }
 
-function pbc-files() { "$PBC" files --ns "$PBS_NAMESPACE" "$@"; }
+function pbc-files() { "$PBC" files "${PBC_ARGS[@]}" "$@"; }
 
-function pbc-catalog-shell() { "$PBC" catalog shell --ns "$PBS_NAMESPACE" "$@"; }
+function pbc-catalog-shell() { "$PBC" catalog shell "${PBC_ARGS[@]}" "${KEY_ARGS[@]}" "$@"; }
 
-function pbc-mount() { "$PBC" mount --ns "$PBS_NAMESPACE" "$@"; }
+function pbc-mount() { "$PBC" mount "${PBC_ARGS[@]}" "${KEY_ARGS[@]}" "$@"; }
 
 function get_group_names() {
   pbc-list --output-format json | jq -r '.[] | "\(.["backup-type"])/\(.["backup-id"])"'
@@ -84,7 +86,6 @@ function apt_get_install() {
   return $rc
 }
 
-WORK_DIR=''
 function cleanup_work_dir() {
   [ -n "$WORK_DIR" ] && [ -d "$WORK_DIR" ] && rm -r "$WORK_DIR"
   trap - EXIT
@@ -141,7 +142,6 @@ function install_proxmox_backup_client() {
   cleanup_work_dir
 }
 
-
 function arr_contains() {
   local search=$1
   shift
@@ -181,24 +181,27 @@ function may_select() {
 }
 
 function select_group() {
-  local groups
+  local groups raw
-  readarray -t groups < <(get_group_names)
+  raw=$(get_group_names) || { echo "Error: failed to query PBS!" >&2; return 1; }
-  (( ${#groups[@]} == 0 )) && return 2
+  [ -z "$raw" ] && return 2
+  readarray -t groups <<< "$raw"
 
   PS3="Snapshot group [1-${#groups[@]}]: "
   GROUP=$(may_select "$1" "${groups[@]}") || { echo "Error: invalid group" >&2; return 1; }
 }
 
 function select_snapshot_and_archive() {
-  local snapshots archives
+  local snapshots archives raw
-  readarray -t snapshots < <(get_snapshot_names)
+  raw=$(get_snapshot_names) || { echo "Error: failed to query PBS!" >&2; return 1; }
-  (( ${#snapshots[@]} == 0 )) && return 2
+  [ -z "$raw" ] && return 2
+  readarray -t snapshots <<< "$raw"
 
   PS3="Snapshot [1-${#snapshots[@]}]: "
   SNAPSHOT=$(may_select "$1" "${snapshots[@]}") || { echo "Error: invalid snapshot" >&2; return 1; }
 
-  readarray -t archives < <(get_snapshot_files "$SNAPSHOT")
+  raw=$(get_snapshot_files "$SNAPSHOT") || { echo "Error: failed to query PBS!" >&2; return 1; }
-  (( ${#archives[@]} == 0 )) && return 3
+  [ -z "$raw" ] && return 3
+  readarray -t archives <<< "$raw"
 
   PS3="Archive [1-${#archives[@]}]: "
   ARCHIVE=$(may_select "$2" "${archives[@]}") || { echo "Error: invalid archive" >&2; return 1; }
@@ -270,7 +273,6 @@ while (( $# > 0 )); do
   fi
 done
 
-
 if [ -f "$cfgfile" ]; then
   perms=$(stat -c '%a' "$cfgfile")
   (( 8#$perms & 0022 )) && echo "Error: $cfgfile is writable by group or others!" >&2 && exit 202
@@ -302,8 +304,20 @@ else
   [ ! -f "$PBC" ] && echo "Error: $PBC: no such file" >&2 && exit 200
   [ ! -x "$PBC" ] && echo "Error: $PBC: not executable" >&2 && exit 200
   ! command -v jq >/dev/null && echo "Error: jq executable not found!" >&2 && exit 200
+  if [ -n "$ENCRYPTION_KEYFILE" ]; then
+    [ ! -f "$ENCRYPTION_KEYFILE" ] && echo "Error: $ENCRYPTION_KEYFILE: no such file" >&2 && exit 203
+    [ ! -r "$ENCRYPTION_KEYFILE" ] && echo "Error: $ENCRYPTION_KEYFILE: not readable" >&2 && exit 203
+    perms=$(stat -c '%a' "$ENCRYPTION_KEYFILE")
+    (( 8#$perms & 0007 )) && echo "Warning: $ENCRYPTION_KEYFILE is readable by others!" >&2
+  fi
 fi
 
+PBC_ARGS=()
+KEY_ARGS=()
+
+[ -n "$PBS_NAMESPACE" ] && PBC_ARGS+=('--ns' "$PBS_NAMESPACE")
+[ -n "$ENCRYPTION_KEYFILE" ] && KEY_ARGS+=('--keyfile' "$ENCRYPTION_KEYFILE")
+
 export PBS_REPOSITORY="$PBS_USER@$PBS_SERVER:$PBS_DATASTORE"
 export PBS_PASSWORD="$PBS_PASSWORD"
 
@@ -355,9 +369,10 @@ case "$action" in
     target=${args[2]}
 
     if [ -z "$target" ]; then
+      [ ! -t 0 ] && echo "Error: no target path given and stdin is not a terminal" >&2 && exit 1
       while [ -z "$target" ]; do
         echo -n "Target path: "
-        read -r target
+        ! read -r target && [ -z "$target" ] && echo "Error: no target path given" >&2 && exit 1
         [ -d "$target" ] && break
         echo -e "\nError: $target: no such directory\n" >&2
         target=''
@@ -387,11 +402,9 @@ case "$action" in
     fi
 
     if [ -f "$SCRIPT_DIR/config.example" ]; then
-      if $update_pbc || [ ! -f "$ETC_DIR/config.example" ]; then
       echo "Install example config to $ETC_DIR/config.example ..."
       ! install -m 0640 "$SCRIPT_DIR/config.example" "$ETC_DIR/config.example" && echo "Error installing file!" >&2 && exit 4
     fi
-    fi
 
     echo "Info: successfully installed pbc dependencies"
   ;;