Initial QSfera import

Server/vendor/github.com/gookit/goutil/internal/checkfn/sysenv.go

@@ -0,0 +1,40 @@
+package checkfn
+
+import (
+	"os"
+	"strings"
+)
+
+var detectedWSL bool
+var detectedWSLContents string
+
+// IsWSL system env
+// https://github.com/Microsoft/WSL/issues/423#issuecomment-221627364
+func IsWSL() bool {
+	// ENV:
+	// 	WSL_DISTRO_NAME=Debian
+	if len(os.Getenv("WSL_DISTRO_NAME")) > 0 {
+		return true
+	}
+
+	if !detectedWSL {
+		b := make([]byte, 1024)
+		// `cat /proc/version`
+		// on mac:
+		// 	!not the file!
+		// on linux(debian,ubuntu,alpine):
+		//	Linux version 4.19.121-linuxkit (root@18b3f92ade35) (gcc version 9.2.0 (Alpine 9.2.0)) #1 SMP Thu Jan 21 15:36:34 UTC 2021
+		// on win git bash, conEmu:
+		// 	MINGW64_NT-10.0-19042 version 3.1.7-340.x86_64 (@WIN-N0G619FD3UK) (gcc version 9.3.0 (GCC) ) 2020-10-23 13:08 UTC
+		// on WSL:
+		//  Linux version 4.4.0-19041-Microsoft (Microsoft@Microsoft.com) (gcc version 5.4.0 (GCC) ) #488-Microsoft Mon Sep 01 13:43:00 PST 2020
+		f, err := os.Open("/proc/version")
+		if err == nil {
+			_, _ = f.Read(b) // ignore error
+			f.Close()
+			detectedWSLContents = string(b)
+		}
+		detectedWSL = true
+	}
+	return strings.Contains(detectedWSLContents, "Microsoft")
+}