Add install from source script

Add script to help users automatically install from source on supported
distributions.

src/linux/Packaging.Linux/install-from-source.sh

@@ -0,0 +1,183 @@
+#!/bin/sh
+
+# halt execution immediately on failure
+# note there are some scenarios in which this will not exit;
+# see https://www.gnu.org/software/bash/manual/html_node/The-Set-Builtin.html
+# for additional details
+set -e
+
+is_ci=
+for i in "$@"; do
+    case "$i" in
+        -y)
+        is_ci=true
+        shift # past argument=value
+        ;;
+    esac
+done
+
+# in non-ci scenarios, advertise what we will be doing and
+# give user the option to exit
+if [ -z $is_ci ]; then
+    echo "This script will download, compile, and install Git Credential Manager to:
+
+    /usr/local/bin
+
+Git Credential Manager is licensed under the MIT License: https://aka.ms/gcm/license"
+
+    while true; do
+        read -p "Do you want to continue? [Y/n] " yn
+        case $yn in
+            [Yy]*|"")
+                break
+            ;;
+            [Nn]*)
+                exit
+            ;;
+            *) 
+                echo "Please answer yes or no."
+            ;;
+        esac
+    done
+fi
+
+install_shared_packages() {
+    pkg_manager=$1
+    install_verb=$2
+
+    local shared_packages="git curl"
+    for package in $shared_packages; do
+        # ensure we don't stomp on existing installations
+        if [ ! -z $(which $package) ]; then
+            continue
+        fi
+
+        if [ $pkg_manager = apk ]; then
+            $sudo_cmd $pkg_manager $install_verb $package
+        else
+            $sudo_cmd $pkg_manager $install_verb $package -y
+        fi
+    done
+}
+
+ensure_dotnet_installed() {
+    if [ -z "$(verify_existing_dotnet_installation)" ]; then
+        curl -LO https://dot.net/v1/dotnet-install.sh
+        chmod +x ./dotnet-install.sh
+        bash -c "./dotnet-install.sh"
+
+        # since we have to run the dotnet install script with bash, dotnet isn't added
+        # to the process PATH, so we manually add it here
+        cd ~
+        export DOTNET_ROOT=$(pwd)/.dotnet
+        add_to_PATH $DOTNET_ROOT
+    fi
+}
+
+verify_existing_dotnet_installation() {
+    # get initial pieces of installed sdk version(s)
+    sdks=$(dotnet --list-sdks | cut -c 1-3)
+
+    # if we have a supported version installed, return
+    supported_dotnet_versions="6.0 5.0"
+    for v in $supported_dotnet_versions; do
+        if [ $(echo $sdks | grep "$v") ]; then
+            echo $sdks
+        fi
+    done
+}
+
+add_to_PATH () {
+  for directory; do
+    if [ ! -d "$directory" ]; then
+        continue; # skip nonexistent directory
+    fi
+    case ":$PATH:" in
+        *":$directory:"*)
+            break
+        ;;
+        *)
+            export PATH=$PATH:$directory
+        ;;
+    esac
+  done
+}
+
+sudo_cmd=
+
+# if the user isn't root, we need to use `sudo` for certain commands
+# (e.g. installing packages)
+if [ -z "$sudo_cmd" ]; then
+    if [ `id -u` != 0 ]; then
+        sudo_cmd=sudo
+    fi
+fi
+
+eval "$(sed -n 's/^ID=/distribution=/p' /etc/os-release)"
+eval "$(sed -n 's/^VERSION_ID=/version=/p' /etc/os-release | tr -d '"')"
+case "$distribution" in
+    debian | ubuntu)
+        $sudo_cmd apt update
+        install_shared_packages apt install
+
+        # add dotnet package repository/signing key
+        $sudo_cmd apt update && $sudo_cmd apt install wget -y
+        curl -LO https://packages.microsoft.com/config/"$distribution"/"$version"/packages-microsoft-prod.deb
+        $sudo_cmd dpkg -i packages-microsoft-prod.deb
+        rm packages-microsoft-prod.deb
+
+        # proactively install tzdata to prevent prompts
+        export DEBIAN_FRONTEND=noninteractive
+        $sudo_cmd apt install -y --no-install-recommends tzdata
+
+        # install dotnet packages and dependencies if needed
+        if [ -z "$(verify_existing_dotnet_installation)" ]; then
+            $sudo_cmd apt update
+            $sudo_cmd apt install apt-transport-https -y
+            $sudo_cmd apt update
+            $sudo_cmd apt install dotnet-sdk-5.0 dpkg-dev -y
+        fi
+    ;;
+    linuxmint)
+        $sudo_cmd apt update
+        install_shared_packages apt install
+
+        # install dotnet packages and dependencies
+        $sudo_cmd apt install libc6 libgcc1 libgssapi-krb5-2 libssl1.1 libstdc++6 zlib1g libicu66 -y
+        ensure_dotnet_installed
+    ;;
+    fedora | centos | rhel)
+        $sudo_cmd dnf update -y
+        install_shared_packages dnf install
+
+        # install dotnet/gcm dependencies
+        $sudo_cmd dnf install krb5-libs libicu openssl-libs zlib findutils which bash -y
+
+        ensure_dotnet_installed
+    ;;
+    alpine)
+        $sudo_cmd apk update
+        install_shared_packages apk add
+
+        # install dotnet/gcm dependencies
+        $sudo_cmd apk add icu-libs krb5-libs libgcc libintl libssl1.1 libstdc++ zlib which bash coreutils gcompat
+
+        ensure_dotnet_installed
+    ;;
+    *)
+        echo "ERROR: Unsupported Linux distribution: $distribution"
+        exit
+    ;;
+esac
+
+# detect if the script is part of a full source checkout or standalone instead
+script_path="$(cd "$(dirname "$0")" && pwd)"
+toplevel_path="${script_path%/src/linux/Packaging.Linux}"
+if [ "z$script_path" = "z$toplevel_path" ] || [ ! -f "$toplevel_path/Git-Credential-Manager.sln" ]; then
+    toplevel_path="$PWD/git-credential-manager"
+    test -d "$toplevel_path" || git clone https://github.com/GitCredentialManager/git-credential-manager
+fi
+
+cd "$toplevel_path"
+$sudo_cmd dotnet build ./src/linux/Packaging.Linux/Packaging.Linux.csproj -c Release -p:InstallFromSource=true
+add_to_PATH "/usr/local/bin"