connect

#!/usr/bin/env bash
#
# Connect to a network server and mount a shared drive.
# If no drive letter is specified, unmount the drive.
# Use sudo to run the script with superuser rights.
# Note: Used Bash features that are available in Bash 5.3 and later.
#
# Important! This script uses with launcher.py to securely pass
# sensitive data (username and password) via stdin.
#
# Author: Anton Chernov
# Date: Feb 3, 2026
# License: MIT
#
# Version 1.0.0 - initial release.
# Version 1.1.0 - improved passing sensitive data to subprocess
#                 (replaced environment variables with stdin).
# Version 1.2.0 - without change in functionality, but with code clean up.
#

# Constants
VERSION="1.2.0"
GREEN="\033[0;32m"
YELLOW="\033[1;33m"
RED="\033[0;31m"
NO_COLOR="\033[0m"

# Global variables
use_color=1
logfile=""

# Print usage information
usage() {
	local name=${0##*/}

	cat <<-EOF
	Usage:  $name [-h | -v]
	        $name [-u <username>] [-t <target path>] [-d <drive letter>] [-l <logfile path>]

	Connect to a network server and mount a shared drive.
	Or unmount the drive if no drive letter is specified.

	Options:
    -h                 print this message and exit
    -v                 print version information and exit
    -t <target path>   specify the target mount path (default: /mnt/server)
    -l <logfile path>  specify the path to the logfile (default: ./connection.log)
    -d <drive letter>  specify the drive letter to mount (e.g., g, h, i).
                       If omitted, the script will unmount the drive.
	EOF
}

# Function to get the current timestamp in a human-readable format
get_timestamp() {
    printf '%(%Y-%m-%d %H:%M:%S)T' -1
}

# Function to print log messages
log_print() {
    local color=$1
    local level=$2
    local message=$3

    if [ -n "$color" ]; then
        printf "%b %s - %s\n" \
        "${color}[${level}]${NO_COLOR}" "${ get_timestamp; }" "$message" >&2
    else
        printf "[%s] %s - %s\n" "$level" "${ get_timestamp; }" "$message" >&2
    fi

    printf "[%s] %s - %s\n" \
    "$level" "${ get_timestamp; }" "$message" >> "$logfile" 2>/dev/null
}

# Function to print error messages and exit
failure() {
    log_print "$RED" "FAIL" "$@"
    exit -1
}

# Function to verify the script's environment
verification() {
    local target_dir="$1"

    # Is an output a terminal?
    if [ ! -t 1 ]; then
        use_color=0
    fi

    # Check logfile path
    if [ -d "$logfile" ]; then
        logfile="${logfile}/connection.log"
    elif [ -z "$logfile" ] || [ "$logfile" = "." ]; then
        logfile="$(pwd)/connection.log"
    fi

    # Check superuser rights
    # if [[ -z "$SUDO_USER" ]]; then
    if [[ $EUID -ne 0 ]]; then
        failure "The script was run without superuser rights."
    fi

    # Check if target directory exists
    if [[ ! -d "$target_dir" ]]; then
        mkdir "$target_dir">/dev/null || \
        failure "Unable to create target directory '$target_dir'."
    fi
}

# Main function
main() {
    # Read sensitive data from stdin
    read -r SERVER_USER
    read -r SERVER_PASS

    # Local variables
    local cmd=
    local drive=
    local action=
    local target='/mnt/server'
    local address='192.168.42.100'
    local OPTIND OPTARG opt
    while getopts 'u:t:d:l:hv' opt; do
        case "$opt" in
            t) target=$OPTARG;;
            d) drive=${OPTARG,,};; # to lowercase
            l) logfile=$OPTARG;;
            h) usage; exit 0;;
            v) echo "$VERSION"; exit 0;;
            *) usage >&2; exit -2;;
        esac
    done

    # Verify the script's environment
    verification "$target"

    if [[ -z "$drive" ]]; then
        cmd="umount $target"
        action="Unmounting network drive from '$target' directory"
    else
        case $drive in
            'd'|'e'|'g'|'h'|'i')
            action="Mounting drive '$drive:' to '$target'"
            cmd="mount -t cifs //$address/$drive$ $target \
                -o username=$SERVER_USER,password=$SERVER_PASS"
            ;;
            *) failure "Invalid drive letter specified: '$drive'.";;
        esac
    fi

    echo 'command:' "$cmd"

    # Execute command and capture output
    local output
    output=${ eval "$cmd" 2>&1 ;}
    # Old way (with subshell):
    # output=$(eval "$cmd" 2>&1)
    local exit_code=$?
    
    if [ $exit_code -eq 0 ]; then
        log_print "$GREEN" "DONE" "$action succeeded."
    else
        log_print "$RED" "FAIL" "$action failed. Exit code: $exit_code"
        if [ -n "$output" ]; then
            log_print "$YELLOW" "INFO" "Command output: $output"
        fi
        exit $exit_code
    fi

}

# Run the main function with all script arguments
main "$@"