app-emulation/lxd/files/0001-lxd-util-Add-HasFilesystem.patch

From ec93b6c088dda4bfd93587d2dd6eb0295ea58f23 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Graber?= <stgraber@ubuntu.com>
Date: Wed, 4 Dec 2019 13:53:05 -0500
Subject: [PATCH 1/2] lxd/util: Add HasFilesystem
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Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
---
 lxd/util/kernel.go | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/lxd/util/kernel.go b/lxd/util/kernel.go
index 6f75915ba..0272dd101 100644
--- a/lxd/util/kernel.go
+++ b/lxd/util/kernel.go
@@ -1,7 +1,10 @@
 package util
 
 import (
+	"bufio"
 	"fmt"
+	"os"
+	"strings"
 
 	"github.com/lxc/lxd/shared"
 )
@@ -16,3 +19,26 @@ func LoadModule(module string) error {
 	_, err := shared.RunCommand("modprobe", module)
 	return err
 }
+
+// HasFilesystem checks whether a given filesystem is already supported
+// by the kernel. Note that if the filesystem is a module, you may need to
+// load it first.
+func HasFilesystem(filesystem string) bool {
+	file, err := os.Open("/proc/filesystems")
+	if err != nil {
+		return false
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		fields := strings.Fields(strings.TrimSpace(scanner.Text()))
+		entry := fields[len(fields)-1]
+
+		if entry == filesystem {
+			return true
+		}
+	}
+
+	return false
+}
-- 
2.24.0.393.g34dc348eaf-goog