#! /bin/sh
# $Id: osql,v 1.12 2011-05-11 03:08:13 jklowden Exp $
#
# Check odbc.ini, odbcinst, and, optionally, freetds.conf, 
# then execute isql (assume it's unixODBC's isql).  
#

USAGE="Syntax: $(basename $0) -S server -U user -P password"

while getopts I:S:U:P: OPTION
do
	case ${OPTION} in
		I)	OVER_DIR=${OPTARG}	# override
			;;
		S)	DSN=${OPTARG}
			;;
		U)	USERNAME=${OPTARG}
			;;
		P)	PASSWORD=${OPTARG}
			;;
		\?)     echo $USAGE
			exit 1
			;;
	esac
done

#cho ${DSN} ${USERNAME} ${PASSWORD}
if [ -z "${DSN}" -o -z "${USERNAME}" -o -z "${PASSWORD}" ]
then 
	
	echo $USAGE
	exit 1
fi

ISQL=$(command -v isql)
if [ -z "${ISQL}" ]
then
	echo "$(basename $0): error: no \"isql\" command found.  Is unixODBC installed?"
	exit 1
fi

# Establish ODBC prefix directory

ISQL_DIR=$(strings ${ISQL} | grep ^/ | grep -v elf | grep -v '\.so\.' | head -1 | sed 's/lib$/etc/' )

INI_DIRNAME="/tmp/$(basename $0).$$"
exec 3> ${INI_DIRNAME}

# Check the libraries, too. 
if [ -z "${OVER_DIR}" ]
then 
	echo "checking shared odbc libraries linked to isql for default directories..."
	(echo ${ISQL_DIR}; ldd "${ISQL}" | awk '/libodbc\./ {print $3}') \
	| while read L
	  do 
	  	strings "$L" | grep '^/' | grep -v '/lib' \
		| while read D 
		  do 
		  	if [ ! -s "${INI_DIRNAME}" ]
			then
			  	printf "	trying $D ... "
			  	if [ -d "$D" -a -r "${D}/odbc.ini" ]
				then
					printf $D >&3
					printf "OK"
				else
					printf "no"
				fi
				printf "\n"
			fi
		  done
	  done
fi

ODBC_DIR=$(cat ${INI_DIRNAME}) && rm ${INI_DIRNAME}

if [ -z "${ODBC_DIR}" -a -z "${OVER_DIR}" ]
then
	echo "$(basename $0): problem: no potential directory strings in \"$(command -v isql)\""
	echo "$(basename $0): advice: use \"osql -I DIR\" where DIR unixODBC\'s install prefix e.g. /usr/local"
	echo "isql strings are:"
	strings ${ISQL} | grep ^/ | sed 's/^/+ /'
	#xit 1
fi

if [ "${OVER_DIR}" ]
then
	if [ -d "${ODBC_DIR}" ]
	then
		echo "\"${ODBC_DIR}\" is a directory, overridden by"
	else 
		echo "\"${ODBC_DIR}\" is NOT a directory, overridden by"
	fi
	echo "\"${OVER_DIR}\"."
	
	if [ -d "${OVER_DIR}" ]
	then
		ODBC_DIR=${OVER_DIR}
	else
		echo "$(basename $0): error: \"${OVER_DIR}\" is not a directory"
		exit 1
	fi
fi

# Look for server entry in odbc.ini 
echo 'checking odbc.ini files'
for F in "${HOME}/.odbc.ini" "${ODBC_DIR}/odbc.ini"
do
	if [ ! -d "$(dirname $F)" ]
	then
		echo "warning: $(dirname $F) is not a directory" 
		continue
	fi
	
	if [ -r "$F" ]
	then
		echo "	reading $F"
	else
		echo "	cannot read \"$F\""
		continue
	fi

	grep -F "[${DSN}]" $F > /dev/null

	if [ $? -eq 0 ]
	then
		echo "[${DSN}] found in $F"
		ODBC_INI=$F
		break
	else
		echo "[${DSN}] not found in $F"
	fi
done

if [ -z "${ODBC_INI}" ]
then
	echo "$(basename $0): error: unable to locate ${DSN} in any odbc.ini"
	exit 1
fi

# Report finding of server entry
echo found this section:
SED_CMD="/^\[${DSN}\]/,/^[[:space:]]*$/ { s/^/	/; p; }"
sed -ne "${SED_CMD}" ${ODBC_INI}

#
# Examine server entry in odbc.ini 
#

# Find the driver in the servername or default section
for D in "${DSN}" 'default' 
do
	echo "looking for driver for DSN [$D] in ${ODBC_INI}"
	grep "$D" ${ODBC_INI} > /dev/null
	if [ $? -eq 0 ]
	then
		CMD="/^\[$D\]/,/^[[:space:]]*$/ { s/^/	/; p; }"
		DRIVER_LINE=$(sed -ne "${CMD}" ${ODBC_INI} \
				| grep -Ei '^[[:space:]]*driver[[:space:]]*=')
		if [ -z "${DRIVER_LINE}" ]
		then
			echo "  no driver mentioned for [$D] in $(basename ${ODBC_INI})"
			continue
		fi

		echo "  found driver line: \"${DRIVER_LINE}\""
		DRIVER=$(echo ${DRIVER_LINE} \
		    | awk -F ' *= *' '{print $2}' \
		    | sed 's/[[:space:]][[:space:]]*//g')
		if [ "${DRIVER}" ]
		then
			echo "  driver \"${DRIVER}\" found for [$D] in $(basename ${ODBC_INI})"
			break
		else
			echo "  driver line for [$D] incomplete in $(basename ${ODBC_INI})"
			continue
		fi
	fi
done

if [ -z "${DRIVER}" ]
then
	echo "$(basename $0): error: no driver found for [${DSN}] in $(basename ${ODBC_INI})"
	exit 1
fi

# get filename of driver
echo found driver named \"${DRIVER}\"
if [ -d "${DRIVER}" -o ! -x "${DRIVER}" ]
then
	# not a filename, look it up
	DRIVERNAME=${DRIVER}
	ODBC_INST="${ODBC_DIR}/odbcinst.ini"
	echo "\"${DRIVERNAME}\" is not an executable file"
	echo "looking for entry named [${DRIVERNAME}] in ${ODBC_INST}"

	grep "${DRIVERNAME}" ${ODBC_INST} > /dev/null
	if [ $? -ne 0 ]
	then
		if [ $? -eq 1 ]
		then
			echo "$(basename $0): error: no driver entry [${DRIVERNAME}] in ${ODBC_INST}"
		fi
		exit 1;
	fi
	
	CMD="/^\[${DRIVERNAME}\]/,/^[[:space:]]*$/ { s/^/	/; p; }"
	DRIVER_LINE=$(sed -ne "${CMD}" ${ODBC_INST} \
				| grep -Ei '^[[:space:]]*driver[[:space:]]*=')
	if [ -z "${DRIVER_LINE}" ]
	then
		echo "$(basename $0): no driver mentioned for [${DRIVERNAME}] in $(basename ${ODBC_INST})"
		exit 1
	fi

	echo "  found driver line: \"${DRIVER_LINE}\""
	DRIVER=$(echo ${DRIVER_LINE} | awk -F ' *= *' '{print $2}')
	if [ -z "${DRIVER}" ]
	then
		echo "$(basename $0): driver line incomplete for [${DRIVERNAME}] in $(basename ${ODBC_INST})"
		exit 1
	fi

	echo "  found driver ${DRIVER} for [${DRIVERNAME}] in $(basename ${ODBC_INST})"
fi

if [ -z "${DRIVER}" ]
then
	echo $(basename $0): 'error: sorry, failed sanity check: ${DRIVER} is null' 
	exit 1
fi

if [ -x "${DRIVER}" ]
then
	echo "${DRIVER} is an executable file"
else
	echo "${DRIVER} is not an executable file"
	echo "$(basename $0): error: no driver found for ${DSN}"
	exit 1
fi

# find the server/servername
SERVER_LINE=$(sed -ne "${SED_CMD}" ${ODBC_INI} \
		| grep -Ei '^[[:space:]]*server(name)*[[:space:]]*=')

ATTRIBUTE=$(echo ${SERVER_LINE} | awk -F' *= *' '{print $1}')

if [ -z "${ATTRIBUTE}" ]
then
	echo "$(basename $0): neither \"Server\" nor \"Servername\" found for [${DSN}] in $(basename ${ODBC_INI})"
	exit 1
fi

echo ${SERVER_LINE} | grep -i servername >/dev/null

#
# Find the server's hostname 
#
if [ $? -eq 0 ] # ODBC-Combined
then
	TDS_SERVER=$(echo ${SERVER_LINE} | awk -F ' *= *' '{print $2}')
	echo 'Using ODBC-Combined strategy'
	echo "DSN [${DSN}] has servername \"${TDS_SERVER}\" (from ${ODBC_INI})"
	if [ -z "${TDS_SERVER}" ]
	then
		exit 1
	fi

	# Look for $TDS_SERVER in freetds.conf 
	
	FREETDS_DIR=$(tsql -C | grep 'freetds.conf directory' | awk -F: '{print $2}' | sed 's/^ *//')
	if [ -z "${FREETDS_DIR}" ]
	then
		echo "$(basename $0): error: unable to locate directory for freetds.conf using \"$(command -v tsql)\""
		exit 1
	fi
	
	for F in "${HOME}/.freetds.conf" "${FREETDS_DIR}/freetds.conf"
	do
		if [ -r "$F" ]
		then
			echo $F is a readable file
		else
			echo cannot read \"$F\"
			continue
		fi

		echo "looking for [${TDS_SERVER}] in $F"
		grep -F "[${TDS_SERVER}]" $F > /dev/null

		if [ $? -eq 0 ]
		then
			FREETDS_CONF=$F
			break
		else
			echo "[${TDS_SERVER}]" not found in $F
		fi
	done
	
	if [ -z "${FREETDS_CONF}" ]
	then
		echo "$(basename $0): error: unable to locate ${TDS_SERVER} in any freetds.conf"
		exit 1
	fi

	# Examine server entry in freetds.conf 

	echo found this section:
	SED_CMD="/^\[${TDS_SERVER}\]/,/^[[:space:]]*$/ { s/^/	/; p; }"
	sed -ne "${SED_CMD}" ${FREETDS_CONF}

	SERVER_LINE=$(sed -ne "${SED_CMD}" ${FREETDS_CONF} \
			| grep -Ei '^[[:space:]]*host[[:space:]]*=')

	# No character class support in mawk, 
	# cf. "Mawk does not support Posix character classes in expressions"
	# https://bugs.launchpad.net/ubuntu/+source/mawk/+bug/69724
	HOST=$(echo ${SERVER_LINE} | awk -F' *= *' '{print $2}')

	if [ -z "${HOST}" ]
	then
		echo "$(basename $0): no \"host\" entry found for [${TDS_SERVER}] in $(basename ${FREETDS_CONF})"
		exit 1
	fi
	
else # odbc.ini contains a "server", a DNS host
	HOST=$(echo ${SERVER_LINE} | awk -F ' *= *' '{print $2}')
	echo "\"${ATTRIBUTE}\" found, not using freetds.conf"
	echo "${ATTRIBUTE} is \"${HOST}\""
	if [ -z "${HOST}" ]
	then
		echo "$(basename $0): no value found for \"${ATTRIBUTE}\" entry in $(basename ${ODBC_INI})"
		exit 1
	fi
fi

# If the "host" is an ip address, look up the name, for neatness, e.g. 
## $ host 10.81.36.39
## 39.36.81.10.IN-ADDR.ARPA domain name pointer ntc5003.eg.com
if [ "${HOST}" = "$(echo ${HOST} | sed 's/[^.0-9]*//')" ]
then 
	ADDRESS=${HOST}
	echo 'looking up hostname for ip address' ${ADDRESS}
	HOST=$(host ${HOST} | awk '/domain/ {print $5}' | sed 's/\.$//')
	if [ -z "${HOST}" ]
	then
		echo "$(basename $0): warning: no DNS hostname found for \"${ADDRESS}\""
		HOST=${ADDRESS}	# restore host address string
	fi
fi

# Now we have a DNS hostname for the server in HOST
if [ "${HOST}" != "${ADDRESS}" ]
then
    ADDRESS=$(host ${HOST} | awk '/has address/ {print $4}' | head -1)
fi
if [ -z "${ADDRESS}" ]
then
	echo "$(basename $0): no IP address found for \"${HOST}\""
	exit 1
fi

#cho ${HOST} has address ${ADDRESS}

# Report what we know and exec isql 

printf "\n"
printf "Configuration looks OK.  Connection details:\n\n"
printf "%22s:\t%-30s\n"  DSN ${DSN}
printf "%22s:\t%-30s\n"  odbc.ini "${ODBC_INI}"
printf "%22s:\t%-30s\n"  Driver ${DRIVER}
printf "%22s:\t%-30s\n" "Server hostname" ${HOST}
printf "%22s:\t%-30s\n"  Address ${ADDRESS}
printf "\n"

echo Attempting connection as ${USERNAME} ... 

if [ -z "${TDSDUMP}" ]
then 
	TDSDUMP_AUTO="/tmp/$(basename $0).dump.$$"
	export TDSDUMP=${TDSDUMP_AUTO}
fi

( set -x; isql ${DSN} ${USERNAME} ${PASSWORD} -v ) \
	|| sed -ne 's/Connecting/FAILED &/p' ${TDSDUMP}

test "${TDSDUMP_AUTO}" && rm -f ${TDSDUMP_AUTO}