Added bmc.sh shell

This "shell" written in BASH provides the basic functionality of the Raspberry Pi BMC, making use of the WiringPi `gpio` command and `sudo` to allow privileged execution of certain functions by a non-root user.

bmc.sh

@@ -0,0 +1,174 @@
+#!/bin/bash
+
+stty eof undef
+stty intr undef
+
+hostsystem="$( cat /etc/bmchost )"
+packages=( screen wiringpi )
+pkgfail=""
+for package in ${packages[@]}; do
+        dpkg -l | grep "^ii  ${package}" &>/dev/null || pkgfail="true"
+done
+if test -n "$pkgfail"; then
+        echo -n "Installing required packages... "
+        sudo apt update &>/dev/null
+        sudo apt install -y ${packages[@]} &>/dev/null
+        echo "done."
+fi
+
+help() {
+        echo -e "Available commands:"
+        echo -e "  \e[1mstate\e[0m - Show the system power state"
+        echo -e "  \e[1mconsole\e[0m - Connect to host via serial console; ^A+D to disconnect"
+        echo -e "  \e[1mpowersw\e[0m - Press power switch on host"
+        echo -e "  \e[1mresetsw\e[0m - Press reset switch on host"
+        echo -e "  \e[1mkill\e[0m - Forcibly power off host"
+        echo -e "  \e[1mhelp\e[0m - This help menu"
+        echo -e "  \e[1mbmc\e[0m - Show BMC information"
+        echo -e "  \e[1mhostname\e[0m - Set BMC hostname"
+        echo -e "  \e[1mpassword\e[0m - Set BMC password"
+        echo -e "  \e[1mshell\e[0m - Start a BMC bash shell"
+        echo -e "  \e[1mexit/logout\e[0m - Disconnect from the BMC"
+}
+bmcinfo() {
+        echo -e "BMC information:"
+        echo -e "  IP address: $( ip -4 addr list eth0 | grep inet | awk '{ print $2 }' )"
+        echo -e "  Hostname: $( hostname )"
+        echo -e "  BMC temperature: $( /opt/vc/bin/vcgencmd measure_temp | awk -F'=' '{ print $2 }' )"
+}
+sethostname() {
+        echo -n "Enter new hostname: "
+        read newhostname
+        sudo sed -i '/^127.0.1.1/d' /etc/hosts &>/dev/null
+        sudo tee -a /etc/hosts <<<"127.0.1.1 $newhostname" &>/dev/null
+        sudo hostname $newhostname &>/dev/null
+        sudo tee /etc/hostname <<<"$newhostname" &>/dev/null
+        echo "Hostname set to $newhostname"
+}
+setpassword() {
+        echo -n "Enter new BMC password: "
+        read -s password_1
+        echo
+        echo -n "Reenter new BMC password: "
+        read -s password_2
+        echo
+        if [ "${password_1}" == "${password_2}" ]; then
+                echo -n "Setting BMC password... "
+                sudo chpasswd <<<"bmc:${password_1}"
+                echo "done."
+        else
+                echo "Passwords to not match!"
+        fi
+}
+resetsw() {
+        echo -n "Pressing reset switch... "
+        gpio mode 0 out
+        gpio write 0 1
+        gpio write 0 0
+        sleep 1
+        echo "done."
+}
+powersw() {
+        if [ "$1" == "hard" ]; then
+                delay='sleep 10'
+                echo -n "Holding power switch... "
+        else
+                delay='sleep 1'
+                echo -n "Pressing power switch... "
+        fi
+        gpio mode 1 out
+        gpio write 1 1
+        $delay
+        gpio write 1 0
+        sleep 2
+        echo "done."
+}
+readpower() {
+        gpio mode 2 in
+        powerstate_raw=$(gpio read 2)
+        if [ "${powerstate_raw}" -eq 1 ]; then
+                powerstate="\e[32mOn\e[0m"
+        else
+                powerstate="\e[31mOff\e[0m"
+        fi
+}
+
+readpower
+echo
+echo -e "--------------------"
+echo -e "| Raspberry Pi BMC |"
+echo -e "--------------------"
+echo
+echo -e "Host system: \e[1m${hostsystem}\e[0m"
+echo -e "Host state: $powerstate"
+echo
+help
+echo
+while true; do
+stty eof undef
+stty intr undef
+echo -en "\e[1m\e[34m[$(hostname)]>\e[0m "
+read input
+case $input in
+        'state')
+                readpower
+                echo -e "Host state: $powerstate"
+                echo
+        ;;
+        'console')
+                echo "Starting console..."
+                sudo screen -r serialconsole &>/dev/null || sudo screen -S serialconsole /dev/ttyUSB0 115200
+                echo
+        ;;
+        'powersw')
+                powersw soft
+                readpower
+                echo -e "Host state: $powerstate"
+                echo
+        ;;
+        'resetsw')
+                resetsw
+                readpower
+                echo -e "Host state: $powerstate"
+                echo
+        ;;
+        'kill')
+                powersw hard
+                readpower
+                echo -e "Host state: $powerstate"
+                echo
+        ;;
+        'help')
+                help
+                echo
+        ;;
+        'bmc')
+                bmcinfo
+                echo
+        ;;
+        'hostname')
+                sethostname
+                echo
+        ;;
+        'password')
+                setpassword
+                echo
+        ;;
+        'shell')
+                stty sane
+                /bin/bash
+                help
+                echo
+        ;;
+        'exit'|'logout')
+                exit 0
+        ;;
+        '')
+                continue
+        ;;
+        *)
+                echo "Invalid command."
+                echo
+        ;;
+esac
+done