Beiträge von LukeGee

################################################################################
# shellfuncs - some useful bash functions
################################################################################


PATH=/usr/bin:/usr/sbin:/bin:/sbin


#
# Activates of deactivates verbosity of some functions in here.
#
: ${LIB_VERBOSE:=0}


################################################################################
# Default return codes as in stdlibc
################################################################################


EXIT_SUCCESS=0
EXIT_FAILURE=1


################################################################################
# THE FUNCTIONS
################################################################################


################################################################################
# is_true
#	check pseudo-boolean values
#
# Usage:
#	is_true [value]
#
# Arguments:
#	value: pseudo-boolean value to check
#
# Returns:
#	true (rc = 0) if the value equals true
#
is_true()
{
	case "$1" in
		yes|true|YES|TRUE|ja|on|ON|1)
			true
			;;
		*)
			false
			;;
	esac
}


################################################################################
# check_rc
#	checks a programs return code for success for failure
#
# Usage:
#	check_rc [rc]
#
# Arguments:
#	rc: return code of a command
#
# Returns:
#	true (rc = 0) for a successful return code.
#
check_rc()
{
	case "$1" in
		0)
			true
			;;
		*)
			false
			;;
	esac
}


################################################################################
# is_decimal
#	Determines if a value is decimal
#
# Usage:
#	is_decimal [value]
#
# Arguments:
#	value: the value to check
#
# Returns:
#	true (rc = 0) for a decimal value
#
is_decimal()
{
	case "$1" in
		""|*[!0-9]*)
			false
			;;
		*)
			true
			;;
	esac
}


################################################################################
# is_decimal
#	Determines if a value is hex
#
# Usage:
#	is_hex [value]
#
# Arguments:
#	value: the value to check
#
# Returns:
#	true (rc = 0) for a hex value
#
is_hex()
{
	case "$1" in
		""|*[!0-9a-fA-F]*)
			false
			;;
		*)
			true
			;;
	esac
}


################################################################################
# is_octal
#	Determines if a value is hex
#
# Usage:
#	is_hex [value]
#
# Arguments:
#	value: the value to check
#
# Returns:
#	true (rc = 0) for a hex value
#
is_octal()
{
	case "$1" in
		""|*[!0-7]*)
			false
			;;
		*)
			true
			;;
	esac
}


################################################################################
# log
#	Logs a message to stdout or stderr
#
# Usage:
#	log [level] [message]
#
# Arguments:
#	level: the log level may be err, info or debug.
#		err means the message is logged to stder(&2)
#		info means the message is logged to stdout(&1)
#		debug means the message if only logged to stdout(&1)
#		if LIB_VERBOSE is set to a true value.
#	message: the message to log
#
log()
{
	if [ $# -lt 2 ]; then
		log err "log: not enough arguments"
	fi


	local level="$1"
	shift
	local msg="$@"


	case "$level" in
		err)
			echo "$msg" >&2
			;;
		info)
			echo "$msg"
			;;
		debug)
			is_true $LIB_VERBOSE && echo "$msg" >&2
			;;
	esac
}


################################################################################
# log_syslog
#	Logs a message to syslog
#	As log tag it takes $0 which means the name of the
#	script executing log_syslog.
#
# Usage:
#	log_syslog [message]
#
# Arguments:
#	message: The message which should be logged
#
log_syslog()
{
	local msg="$@"
	local tag="${0#./}"


	logger -t "$tag" "$msg"
}


################################################################################
# die
#	Logs a message and exits the program with a defined exit code
#
# Usage:
#	die [rc] [message]
#
# Arguments:
#	rc: the exit code to exit the program with
#	message: the message to log to stderr(&2)
#
die()
{
	if [ $# -lt 2 ]; then
		log err "die: not enough arguments"
	fi


	local rc="$1"
	shift
	local msg="$@"


	log err "$msg"


	exit $rc
}


################################################################################
# exec_or_die
#	Executes a command and exits the program if the command failed
#
# Usage:
#	exec_or_die [command args ...]
#
# Arguments:
#	command args ...: the command with its arguments to execute.
#		Does not have to be quoted.
#
exec_or_die()
{
        local cmd="$@"
        local rc


        log debug "exec_or_die: $cmd"


        ( $cmd )
        rc=$?


        if ! check_rc $rc; then
                die $rc "Command $cmd failed with exit code: $rc"
        else
                return $rc
        fi
}


################################################################################
# ARRAY HELPER FUNCTIONS
#
# PLEASE NOTE:
#
# These array functions take use of 'eval'. That means that the arguments
# which repesent the array and vars where data shuold be written to
# have to be written WITHOUT the '$'.
#
# EXAMPLE:
#
# myarray=()
# array_push myarray "first element"
# foovar=
# array_get_first myarray foovar
# echo $foovar
#
################################################################################


################################################################################
# array_push
#	Pushes a value to an array
#
# Usage:
#	array_push [array] [value]
#
# Arguments:
#	array: the array where the values should be pushed to
#	value: the value that should be pushed
#
array_push()
{
	local array="$1"
	shift


	for value in "$@"; do
		eval "$array[\${#$array[@]}]=\$value"
	done
}


################################################################################
# array_get
#	Gets an value from an array an sets it to a var
#
# Usage:
#	array_get [array] [destination] [index]
#
# Arguments:
#	array: the array
#	destination: the destination var
#	indext: the index of the var in the array
#
array_get()
{
	local src="$1"
	local dst="$2"
	local idx="$3"


	eval "$dst=\${$src[$idx]}"
}


################################################################################
# array_get_first
#	Gets the first element of an array
#
# Usage:
#	array_get_first [array] [destination]
#
# Arguments:
#	array: the array where to get the value from
#	value: the value that should be pushed
#
array_get_first()
{
	local src="$1"
	local dst="$2"


	array_get $src $dst 0
}


################################################################################
# array_get_last
#	Gets the last element of an array
#
# Usage:
#	array_get_last [array] [destination]
#
# Arguments:
#	array: the array where to get the value from
#	value: the value that should be pushed
#
array_get_last()
{
	local src="$1"
	local dst="$2"


	array_get $src $dst -1
}


################################################################################
# array_copy
#	Copies an array to another
#
# Usage:
#	array_copy [array] [destination]
#
# Arguments:
#	array: the source array
#	destination: the destination array
#
array_copy()
{
	local src="$1"
	local dst="$2"


	eval "$dst=(\"\${$src[@]}\")"
}


################################################################################
# array_set
#	Sets the value of an array
#
# Usage:
#	array_set [array] [index] [value]
#
# Arguments:
#	array: the array
#	index: the index of the element
#	value: the value that should be set


array_set()
{
	local array="$1"
	local idx="$2"
	local value="$3"


	eval "$array[$idx]=\$value"
}


################################################################################
# array_reset
#	Resets an array to zero or to the defined elements
#
# Usage:
#	array_reset [array] {[values] ...}
#
# Arguments:
#	array: the array that sould be resetted
#	values...: optional values with which the array should be re-initialized
#
array_reset()
{
	local array="$1"
	shift


	eval "$array=(\"\$@\")"
}