#!/system/bin/sh
# fstab.sh
# Reads an fstab-style config and performs mounts/swapon without touching /etc/fstab.
# - Messages go to console AND to $LOG_FILE.
# - Privileged commands (mkdir, mount, swapon) run via: su --mount-master -c "…"
#
# Usage: ./fstab.sh path/to/fstab.conf
# Override log file by exporting LOG_FILE before running.

FSTAB_FILE="$1"

if [ -z "$FSTAB_FILE" ]; then
    echo "Usage: $0 path/to/fstab.conf"
    exit 2
fi

if [ ! -r "$FSTAB_FILE" ]; then
    echo "File '$FSTAB_FILE' not readable."
    exit 2
fi

# Ensure 'su' exists
if ! command -v su >/dev/null 2>&1; then
    echo "ERROR: 'su' not found. Cannot perform privileged operations."
    exit 2
fi

error_count=0
line_no=0

# --- logging helpers (both console and file) ---
log()  { echo "$*" | tee -a "$LOG_FILE"; }
warn() { echo "WARN: $*" | tee -a "$LOG_FILE"; }
err()  { echo "ERROR: $*" | tee -a "$LOG_FILE"; error_count=`expr $error_count + 1`; }

# --- safe single-quoting for building a command string for su -c ---
shell_quote() {
    # Output a single-quoted representation of $1, handling internal single quotes
    # 'abc'd' -> 'abc'"'"'d'
    printf "'%s'" "$(printf "%s" "$1" | sed "s/'/'\"'\"'/g")"
}

# --- run a command as root via su --mount-master -c "..." preserving args safely ---
# Usage: run_root CMD ARG1 ARG2 ...
run_root() {
    cmd="$1"; shift
    # Build a single string: CMD 'ARG1' 'ARG2' ...
    cmdline=$(shell_quote "$cmd")
    for a in "$@"; do
        cmdline="$cmdline $(shell_quote "$a")"
    done
    log "RUN (as root): $cmd $*"
    # Execute
    su $su_options -c "$cmdline"
    rc=$?
    [ $rc -ne 0 ] && err "Command failed (exit $rc): $cmd $*"
    return $rc
}

# --- check if a mountpoint is already mounted (no root needed) ---
is_mounted() {
    mp="$1"
    if command -v mountpoint >/dev/null 2>&1; then
        mountpoint -q "$mp"
        return $?
    fi
    grep -qs " $mp " /proc/mounts
    return $?
}

# --- check if swap device is already active (no root needed) ---
is_swap_active() {
    spec="$1"
    if command -v swapon >/dev/null 2>&1; then
        # Prefer swapon --show if available
        run_root swapon --show=NAME --noheadings 2>/dev/null | grep -Fxq "$spec" && return 0
        basename_spec=`basename "$spec"`
        run_root swapon --show=NAME --noheadings 2>/dev/null | awk -F/ '{print $NF}' | grep -Fxq "$basename_spec" && return 0
        return 1
    fi
    grep -qs "^$spec[[:space:]]" /proc/swaps
    return $?
}

# --- process each fstab line ---
while IFS= read -r rawline || [ -n "$rawline" ]; do
    line_no=`expr $line_no + 1`
    line=`echo "$rawline" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//'`

    case "$line" in
        ""|\#*) continue ;;
    esac

    # spec file vfstype mntops dump pass   (default 0 for last two if missing)
    set -- `echo "$line" | awk '{print $1, $2, $3, $4, ($5? $5:0), ($6? $6:0)}'`
    fs_spec=$1
    fs_file=$2
    fs_vfstype=$3
    fs_mntops=$4
    fs_freq=$5
    fs_pass=$6

    if [ -z "$fs_spec" ] || [ -z "$fs_file" ] || [ -z "$fs_vfstype" ]; then
        warn "Line $line_no: Invalid entry, skipped."
        continue
    fi

    echo "$fs_mntops" | grep -qw noauto && {
        log "Line $line_no: 'noauto' found, skipping $fs_spec -> $fs_file."
        continue
    }

    # --- swap handling ---
    if [ "$fs_vfstype" = "swap" ]; then
        if is_swap_active "$fs_spec"; then
            log "Line $line_no: Swap '$fs_spec' already active — skipped."
            continue
        fi
        if command -v swapon >/dev/null 2>&1; then
            log "Line $line_no: Activating swap: $fs_spec"
            if [ "$fs_mntops" = "-" ]; then
                run_root swapon "$fs_spec" || true
            else
                run_root swapon -o "$fs_mntops" "$fs_spec" || true
            fi
        else
            err "Line $line_no: swapon not available."
        fi
        continue
    fi

    # --- bind / rbind mounts ---
    echo "$fs_mntops" | grep -q bind && {
        if is_mounted "$fs_file"; then
            log "Line $line_no: $fs_file already mounted — skipped."
            continue
        fi
        if [ ! -e "$fs_file" ]; then
            log "Line $line_no: Creating mountpoint $fs_file"
            run_root mkdir -p "$fs_file" || { err "Line $line_no: mkdir failed for $fs_file"; continue; }
        fi
        if echo "$fs_mntops" | grep -qw rbind; then
            log "Line $line_no: rbind mount: $fs_spec -> $fs_file"
            run_root mount --rbind "$fs_spec" "$fs_file" || true
        else
            log "Line $line_no: bind mount: $fs_spec -> $fs_file"
            run_root mount --bind "$fs_spec" "$fs_file" || true
        fi
        continue
    }

    # --- regular filesystem mounts ---
    if is_mounted "$fs_file"; then
        log "Line $line_no: $fs_file already mounted — skipped."
        continue
    fi

    if [ ! -e "$fs_file" ]; then
        log "Line $line_no: Creating mountpoint $fs_file"
        run_root mkdir -p "$fs_file" || { err "Line $line_no: mkdir failed"; continue; }
    fi

    if [ "$fs_mntops" = "-" ]; then
        log "Line $line_no: Mounting $fs_spec -> $fs_file (type=$fs_vfstype)"
        run_root mount -t "$fs_vfstype" "$fs_spec" "$fs_file" || true
    else
        log "Line $line_no: Mounting $fs_spec -> $fs_file (type=$fs_vfstype, opts=$fs_mntops)"
        run_root mount -t "$fs_vfstype" -o "$fs_mntops" "$fs_spec" "$fs_file" || true
    fi
done < "$FSTAB_FILE"

if [ $error_count -gt 0 ]; then
    echo "Done: $error_count errors occurred." | tee -a "$LOG_FILE"
    exit 1
else
    echo "Done: all entries processed successfully." | tee -a "$LOG_FILE"
    exit 0
fi