#!/bin/bash

# This file must be executable to work! chmod 755!

# Automagically mount CIFS shares in the network, similar to

# what autofs -hosts does for NFS.

# Put a line like the following in /etc/auto.master:

# /cifs  /etc/auto.smb --timeout=300

# You'll be able to access Windows and Samba shares in your network

# under /cifs/host.domain/share

# "smbclient -L" is used to obtain a list of shares from the given host.

# In some environments, this requires valid credentials.

# This script knows 2 methods to obtain credentials:

# 1) if a credentials file (see mount.cifs(8)) is present

#    under /etc/creds/$key, use it.

# 2) Otherwise, try to find a usable kerberos credentials cache

#    for the uid of the user that was first to trigger the mount

#    and use that.

# If both methods fail, the script will try to obtain the list

# of shares anonymously.

get_krb5_cache() {

    cache=

    uid=${UID}

    for x in $(ls -d /run/user/$uid/krb5cc_* 2>/dev/null); do

        if [ -d "$x" ] && klist -s DIR:"$x"; then

	    cache=DIR:$x

            return

        fi

    done

    if [ -f /tmp/krb5cc_$uid ] && klist -s /tmp/krb5cc_$uid; then

	    cache=/tmp/krb5cc_$uid

	    return

    fi

}

key="$1"

opts="-fstype=cifs"

for P in /bin /sbin /usr/bin /usr/sbin

do

	if [ -x $P/smbclient ]

	then

		SMBCLIENT=$P/smbclient

		break

	fi

done

[ -x $SMBCLIENT ] || exit 1

creds=/etc/creds/$key

if [ -f "$creds" ]; then

    opts="$opts"',uid=$UID,gid=$GID,credentials='"$creds"

    smbopts="-A $creds"

else

    get_krb5_cache

    if [ -n "$cache" ]; then

        opts="$opts"',multiuser,cruid=$UID,sec=krb5i'

        smbopts="-k"

        export KRB5CCNAME=$cache

    else

        opts="$opts"',guest'

        smbopts="-N"

    fi

fi

$SMBCLIENT $smbopts -gL "$key" 2>/dev/null| awk -v "key=$key" -v "opts=$opts" -F '|' -- '

	BEGIN	{ ORS=""; first=1 }

	/Disk/	{

		  if (first)

			print opts; first=0

		  dir = $2

		  loc = $2

		  # Enclose mount dir and location in quotes

		  # Double quote "$" in location as it is special

		  gsub(/\$$/, "\\$", loc);

		  gsub(/\&/,"\\\\&",loc)

		  print " \\\n\t \"/" dir "\"", "\"://" key "/" loc "\""

		}

	END 	{ if (!first) print "\n"; else exit 1 }

	'