Add Linux system trust support (#2)

Use update-ca-certificates on Debian/Ubuntu based systems, and
update-ca-trust when detected on RHEL/CentOS/Fedora.

truststore_linux.go

@@ -5,9 +5,13 @@
 package main
 
 import (
+	"bytes"
+	"io/ioutil"
 	"log"
 	"os"
+	"os/exec"
 	"path/filepath"
+	"strings"
 )
 
 var (
@@ -15,11 +19,54 @@ var (
 	FirefoxProfile      = os.Getenv("HOME") + "/.mozilla/firefox/*"
 	CertutilInstallHelp = `apt install libnss3-tools" or "yum install nss-tools`
 	NSSBrowsers         = "Firefox and/or Chrome/Chromium"
+
+	SystemTrustFilename string
+	SystemTrustCommand  []string
 )
 
+func init() {
+	_, err := os.Stat("/etc/pki/ca-trust/source/anchors/")
+	if !os.IsNotExist(err) {
+		SystemTrustFilename = "/etc/pki/ca-trust/source/anchors/mkcert-rootCA.pem"
+		SystemTrustCommand = []string{"update-ca-trust", "extract"}
+		return
+	}
+
+	_, err = os.Stat("/usr/local/share/ca-certificates/")
+	if !os.IsNotExist(err) {
+		SystemTrustFilename = "/usr/local/share/ca-certificates/mkcert-rootCA.crt"
+		SystemTrustCommand = []string{"update-ca-certificates"}
+	}
+}
+
 func (m *mkcert) installPlatform() {
-	log.Println("  -install is not yet fully supported on Linux  😣")
-	log.Printf("You can manually install the root certificate at %q in the meantime.", filepath.Join(m.CAROOT, rootName))
+	if SystemTrustCommand == nil {
+		log.Fatalf("-install is not yet supported on this Linux 😣\nYou can manually install the root certificate at %q in the meantime.", filepath.Join(m.CAROOT, rootName))
+	}
+
+	cert, err := ioutil.ReadFile(filepath.Join(m.CAROOT, rootName))
+	fatalIfErr(err, "failed to read root certificate")
+
+	cmd := exec.Command("sudo", "tee", SystemTrustFilename)
+	cmd.Stdin = bytes.NewReader(cert)
+	out, err := cmd.CombinedOutput()
+	fatalIfCmdErr(err, "tee", out)
+
+	cmd = exec.Command("sudo", SystemTrustCommand...)
+	out, err = cmd.CombinedOutput()
+	fatalIfCmdErr(err, strings.Join(SystemTrustCommand, " "), out)
 }
 
-func (m *mkcert) uninstallPlatform() {}
+func (m *mkcert) uninstallPlatform() {
+	if SystemTrustCommand == nil {
+		log.Fatal("-uninstall is not yet supported on this Linux 😣")
+	}
+
+	cmd := exec.Command("sudo", "rm", SystemTrustFilename)
+	out, err := cmd.CombinedOutput()
+	fatalIfCmdErr(err, "rm", out)
+
+	cmd = exec.Command("sudo", SystemTrustCommand...)
+	out, err = cmd.CombinedOutput()
+	fatalIfCmdErr(err, strings.Join(SystemTrustCommand, " "), out)
+}