rebuildfstab ignores "nofstab" or "forensic" if not last boot param

["Andrew" <knoppix@rngresearch.com>]

Dear Klaus,

I did some work on rebuildfstab and would like to propose some additional
changes (see diff below).  I only worked on the udev section of the code
because, as far as I can tell, the legacy ("mode B") section is not being
run by any other programs.  (Is it?)

(@@ -29,19 +29,21 @@)
1.  Checks for boot parameters "nofstab" and "forensic" fail when the
parameter is not at the end of /proc/cmdline.
    Using more complicated patterns only reveals two further problems:
1a. Boot parameter "nofstab" is ignored if "forensic" is present.
1b. Boot parameter "forensic" is ignored if "nofstab" is present and
overridden with $force.
    Instead, I adopted the method from checkbootparam() in /init: looping
through /proc/cmdline checking each parameter.

(@@ -88,9 +90,9 @@)
2.  When $forensic is set, all partitions lose all other options, in
particular, "noauto".
    I assume 'options="ro"' is supposed to be 'options="ro,$options"', of
course, I may be mistaken.

(@@ -105,8 +107,23 @@)
3.  The present check for a manual fstab entry by device name is good, but
device names vary depending on where you plug it in.  I propose the
function check_manual_entry_present(), which additionally checks for LABEL
and UUID entries matching the variables provided by udev.

(@@ -131,25 +148,31 @@)
4.  I think the script should not chown the $MOUNTPOINT directory if it
already exists.
5.  I suggest using check_manual_entry_present() to check DEVNAME LABEL
UUID (vs. DEVNAME only) before calling add_fstab_entry()
6.  I think that when there is a manual entry, the script should not
attempt to rmdir $MOUNTPOINT when a device is removed, because it will not
replace it when the device is added again.

Looking forward to the next revision...

Best regards,
Andrew

--- rebuildfstab-0.6-4/rebuildfstab	2011-07-24 23:54:40.000000000 +0000
+++ rebuildfstab-props/rebuildfstab	2011-08-12 17:10:38.000000000 +0000 @@
-29,19 +29,21 @@
  shift
  arg="$1"
 done
-case "$(cat /proc/cmdline)" in
- *\ nofstab)
+for i in $(cat /proc/cmdline); do
+ case "$i" in
+ nofstab)
   if [ -z "$force" ]; then
    [ -n "$verbose" ] && echo "$0: nofstab bootoption detected, exiting."
>&2
    exit 0
   fi
   ;;
- *\ forensic)
+ forensic)
   forensic="true"
   ;;
-esac
+ esac
+done
 [ ! -r /proc/partitions ] && { echo "$0: /proc not mounted, exiting" >&2;
exit 1; }
 MYPID="$$"
@@ -88,9 +90,9 @@
 # Add or replace udev-generated entry to/in /etc/fstab
 # add_fstab_entry device [mountpoint]
 add_fstab_entry(){
  local device="$1" mountpoint="$2" fstype="$ID_FS_TYPE"
options="noauto,users,exec"
- [ -n "$forensic" ] && options="ro"
+ [ -n "$forensic" ] && options="ro,$options"
  [ -n "$fstype" ] || fstype="auto"
  [ -n "$mountpoint" ] || { mountpoint="${device#/dev/}";
mountpoint="/media/${mountpoint}"; }
  case "$fstype" in
   ntfs*|vfat|msdos)           options="${options},umask=000"
@@ -105,8 +107,23 @@
 $device $mountpoint $fstype $options 0 0
 .
 }
+# check_manual_entry_present device label uuid
+check_manual_entry_present() {
+    local device=$1 label=$2 uuid=$3
+    # udev uses these hex escapes, but only octal escapes are legal in fstab
+    label=${label//\\x20/\\040}; uuid=${uuid//\\x20/\\040};
+    label=${label//\\x09/\\011}; uuid=${uuid//\\x09/\\011};
+    label=${label//\\x0a/\\012}; uuid=${uuid//\\x0a/\\012};
+    label=${label//\\x5c/\\134}; uuid=${uuid//\\x5c/\\134}; # (\134, not
\0134)
+    local pattern="^($device"
+    [ -n "$label" ] && pattern="$pattern|LABEL=$label"
+    [ -n "$uuid" ] && pattern="$pattern|UUID=$uuid"
+    pattern="$pattern)[[:space:]]"
+    grep -qE "$pattern" /etc/fstab
+}
+
 ### MAIN
 ###
 ### We now have two operation modes:
 ### A) do what udev tells us (add/remove partition entries) if DEVNAME
and ACTION is set
@@ -131,25 +148,31 @@
    [ -n "$forensic" ] && blockdev --setro "$DEVNAME" >/dev/null 2>&1 if [
"$ID_FS_TYPE" = "swap" ]; then
     MOUNTPOINT="none"
    else
-    [ -d "$MOUNTPOINT" ] || mkdir -m 755 -p "$MOUNTPOINT"
-    chown "$mpowner"."$mpgroup" "$MOUNTPOINT" 2>/dev/null
+    if ! [ -d "$MOUNTPOINT" ]; then
+     mkdir -m 755 -p "$MOUNTPOINT"
+     chown "$mpowner"."$mpgroup" "$MOUNTPOINT" 2>/dev/null
+    fi
     compat="/mnt/${MOUNTPOINT##*/}"
     [ -d "$compat" -o -L "$compat" ] || ln -sf "$mountpoint" "$compat"
2>/dev/null
    fi
    # Remove auto-generated entry
    remove_fstab_entry "$DEVNAME"
    # Add new entry (if no manually generated is present)
-   grep -q "^$DEVNAME" /etc/fstab || add_fstab_entry "$DEVNAME"
"$MOUNTPOINT"
+   check_manual_entry_present "$DEVNAME" "$ID_FS_LABEL_ENC"
"$ID_FS_UUID_ENC" \
+    || add_fstab_entry "$DEVNAME" "$MOUNTPOINT"
    ;;
   remove)
    if grep -q "^$DEVNAME " /proc/mounts; then
     umount -drf "$DEVNAME" >/dev/null 2>&1
     umount -l "$DEVNAME" >/dev/null 2>&1
    fi
-   [ -d "$MOUNTPOINT" ] && rmdir "$MOUNTPOINT" >/dev/null 2>&1
+   # Remove auto-generated entry
    remove_fstab_entry "$DEVNAME" "$MOUNTPOINT"
+   # Only remove directory if we are in charge for this device
+   check_manual_entry_present "$DEVNAME" \
+    || { [ -d "$MOUNTPOINT" ] && rmdir "$MOUNTPOINT" >/dev/null 2>&1; }
    ;;
  esac
 else # Non-udev behaviour
  [ -n "$verbose" ] && echo "Scanning for new harddisks/partitions..." >&2