From 3a42389ebd0c4eb9350d872e368843e911d275f8 Mon Sep 17 00:00:00 2001
From: KemoNine <kemonine@kemonine.info>
Date: Wed, 26 Aug 2020 01:11:25 -0400
Subject: [PATCH] Initial port of wifi config utility from python 3

---
 cmd/wifi/README.md |   5 ++
 cmd/wifi/wifi.go   | 123 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 cmd/wifi/README.md
 create mode 100644 cmd/wifi/wifi.go

diff --git a/cmd/wifi/README.md b/cmd/wifi/README.md
new file mode 100644
index 0000000..4903652
--- /dev/null
+++ b/cmd/wifi/README.md
@@ -0,0 +1,5 @@
+# wifi
+
+This is the WiFi auto-configuration code for the PiFrame project.
+
+This utility will look for a USB disk containing a ```wifi.txt``` file contianing the ```essid``` and ```password``` for the WiFi setup. If the file is found on a non-mounted USB disk, it will re-configure wifi according to the contents of the file.
diff --git a/cmd/wifi/wifi.go b/cmd/wifi/wifi.go
new file mode 100644
index 0000000..2aa576d
--- /dev/null
+++ b/cmd/wifi/wifi.go
@@ -0,0 +1,123 @@
+package main
+
+import (
+	"io/ioutil"
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// Various commands that we need for this process
+const (
+	CMD_BLKID   = "/usr/sbin/blkid"
+	CMD_FINDMNT = "/usr/bin/findmnt"
+	CMD_MOUNT   = "/usr/bin/mount"
+	CMD_NMCLI   = "/usr/bin/nmcli"
+	CMD_UMOUNT  = "/usr/bin/umount"
+)
+
+// Various file paths we need
+const (
+	MOUNTPOINT       = "/var/wifi"
+	CONFIG_FILE      = "wifi.txt"
+	CONFIG_PATH_FULL = MOUNTPOINT + "/" + CONFIG_FILE
+)
+
+func main() {
+	// Check if mountpoint exists and create if it doesn't
+	if _, err := os.Stat(MOUNTPOINT); os.IsNotExist(err) {
+		if err := os.Mkdir(MOUNTPOINT, 0755); err != nil {
+			log.Fatalf("Could not create mountpoint %s : %s ", MOUNTPOINT, err)
+		}
+	}
+
+	// Find all blkids that we need to evaluate for wifi config
+	blkidOut, err := exec.Command(CMD_BLKID, "-o", "device").Output()
+	if err != nil {
+		log.Fatalf("Error running %s : %s", CMD_BLKID, err)
+	}
+	blkids := string(blkidOut)
+	// Check blkids to see if they are already mounted
+	//     skip if mounted, skip zram (never mounted) as well
+	for _, blkid := range strings.Split(strings.TrimSuffix(blkids, "\n"), "\n") {
+		if blkid == "" || strings.Contains(blkid, "zram") {
+			continue
+		}
+		// SKIP err check here, findmnt will exit w/ status 1 if it's not mounted
+		//     We obviously don't care if it can't find a mountpoint, that's the intent here
+		findmntOut, _ := exec.Command(CMD_FINDMNT, "-n", "-o", "TARGET", blkid).Output()
+		mnt := strings.Trim(string(findmntOut), "\n")
+		if mnt == "" {
+			// Mount the unmounted volume
+			err := exec.Command(CMD_MOUNT, blkid, MOUNTPOINT).Run()
+			if err != nil {
+				log.Fatalf("Could not mount %s : %s", blkid, err)
+			}
+			// Check if the wifi config exists at the new mountpoint, we don't care if it's not present so just keep going
+			if _, err := os.Stat(CONFIG_PATH_FULL); os.IsNotExist(err) {
+				if err != nil {
+					log.Println("WiFi config not found")
+					err := exec.Command(CMD_UMOUNT, MOUNTPOINT).Run()
+					if err != nil {
+						log.Fatalf("Could not unmount %s : %s ", MOUNTPOINT, err)
+					}
+					continue
+				}
+			}
+			// Sanity check config file
+			stat, err := os.Stat(CONFIG_PATH_FULL)
+			if err != nil {
+				log.Fatalf("Error getting config file information : %s", err)
+			}
+			if stat.Size() > 100000 {
+				log.Fatal("Config is >100kb, cannot process")
+			}
+			if !stat.Mode().IsRegular() {
+				log.Fatal("Config is NOT a regular (TEXT) file, cannot process")
+			}
+			// Open and read wifi config file
+			configFileContents, err := ioutil.ReadFile(CONFIG_PATH_FULL)
+			if err != nil {
+				log.Fatalf("Error reading file %s : %s", CONFIG_PATH_FULL, err)
+			}
+			config := strings.Split(strings.Trim(string(configFileContents), "\n"), "\n")
+			// Final sanity checks
+			if len(config) != 2 {
+				log.Fatal("Config has incorrect number of lines, it should only be 2 lines")
+			}
+			// Doing stuff with the file contents goes here
+			essid := config[0]
+			password := config[1]
+			log.Printf("Using config: %s / %s for WiFi\n", essid, password)
+			// Cleanup existing WiFi connections
+			nmcliOut, err := exec.Command(CMD_NMCLI, "-t", "connection", "show").Output()
+			if err != nil {
+				log.Fatalf("Error running %s : %s", CMD_NMCLI, err)
+			}
+			connections := strings.Split(strings.Trim(string(nmcliOut), "\n"), "\n")
+			for _, connection := range connections {
+				details := strings.Split(connection, ":")
+				if details[2] != "802-11-wireless" {
+					continue
+				}
+				log.Printf("Cleaning up WiFi connection %s", details[0])
+				err := exec.Command(CMD_NMCLI, "connection", "del", details[1]).Run()
+				if err != nil {
+					log.Fatalf("Error running %s : %s", CMD_NMCLI, err)
+				}
+			}
+			// Create new WiFi connection with network manager
+			log.Printf("Connecting to %s with password %s\n", essid, password)
+			err = exec.Command(CMD_NMCLI, "d", "wifi", "connect", essid, "password", password).Run()
+			if err != nil {
+				log.Fatalf("Error running %s : %s", CMD_NMCLI, err)
+			}
+			// Unmount the filesystem and continue
+			err = exec.Command(CMD_UMOUNT, MOUNTPOINT).Run()
+			if err != nil {
+				log.Fatalf("Could not unmount %s : %s ", MOUNTPOINT, err)
+			}
+		}
+	}
+}