🧹 ensure we use fqdn for hostname platform id on unix systems (#3166)

providers/os/id/hostname/hostname.go

@@ -13,6 +13,11 @@ import (
 	"go.mondoo.com/cnquery/v10/providers/os/connection/shared"
 )
 
+// Hostname returns the hostname of the system.
+
+// On Linux systems we prefer `hostname -f` over `/etc/hostname` since systemd is not updating the value all the time.
+// On Windows the `hostname` command (without the -f flag) works more reliable than `powershell -c "$env:computername"`
+// since it will return a non-zero exit code.
 func Hostname(conn shared.Connection, pf *inventory.Platform) (string, bool) {
 	var hostname string
 
@@ -21,23 +26,32 @@ func Hostname(conn shared.Connection, pf *inventory.Platform) (string, bool) {
 		return hostname, false
 	}
 
-	// linux:
-	// we prefer the hostname over /etc/hostname since systemd is not updating the value all the time
-	//
-	// windows:
-	// hostname command works more reliable than t.RunCommand("powershell -c \"$env:computername\"")
-	// since it will return a non-zero exit code.
+	// on unix systems we try to get the hostname via `hostname -f` first since it returns the fqdn
+	if pf.IsFamily(inventory.FAMILY_UNIX) {
+		cmd, err := conn.RunCommand("hostname -f")
+		if err == nil && cmd.ExitStatus == 0 {
+			data, err := io.ReadAll(cmd.Stdout)
+			if err == nil {
+				return strings.TrimSpace(string(data)), true
+			}
+		} else {
+			log.Debug().Err(err).Msg("could not run `hostname -f` command")
+		}
+	}
+
+	// This is the preferred way to get the hostname on windows, it is important to not use the -f flag here
 	cmd, err := conn.RunCommand("hostname")
 	if err == nil && cmd.ExitStatus == 0 {
 		data, err := io.ReadAll(cmd.Stdout)
 		if err == nil {
 			return strings.TrimSpace(string(data)), true
 		}
 	} else {
-		log.Debug().Err(err).Msg("could not run hostname command")
+		log.Debug().Err(err).Msg("could not run `hostname` command")
 	}
 
-	// try to use /etc/hostname since it's also working on static analysis
+	// Fallback to for unix systems to /etc/hostname, since hostname command is not available on all systems
+	// This mechanism is also working for static analysis
 	if pf.IsFamily(inventory.FAMILY_LINUX) {
 		afs := &afero.Afero{Fs: conn.FileSystem()}
 		ok, err := afs.Exists("/etc/hostname")

providers/os/id/hostname/hostname_test.go

@@ -37,6 +37,18 @@ func TestHostnameLinux(t *testing.T) {
 	assert.Equal(t, "abefed34cc9c", hostame)
 }
 
+func TestHostnameLinuxFqdn(t *testing.T) {
+	conn, err := mock.New("./testdata/hostname_fqdn.toml", nil)
+	require.NoError(t, err)
+	platform, ok := detector.DetectOS(conn)
+	require.True(t, ok)
+
+	hostame, ok := hostname.Hostname(conn, platform)
+	require.True(t, ok)
+
+	assert.Equal(t, "myhost.example.com", hostame)
+}
+
 func TestHostnameWindows(t *testing.T) {
 	conn, err := mock.New("./testdata/hostname_windows.toml", nil)
 	require.NoError(t, err)

providers/os/id/hostname/testdata/hostname_fqdn.toml

@@ -0,0 +1,36 @@
+[commands."hostname"]
+stdout="myhost"
+
+[commands."hostname -f"]
+stdout="myhost.example.com"
+
+[commands."uname -s"]
+stdout = "Linux"
+
+[commands."uname -m"]
+stdout = "x86_64"
+
+[commands."uname -r"]
+stdout = "4.9.125-linuxkit"
+
+[files."/etc/redhat-release"]
+content = "Red Hat Enterprise Linux Server release 7.2 (Maipo)"
+
+[files."/etc/os-release"]
+content = """
+NAME="Red Hat Enterprise Linux Server"
+VERSION="7.2 (Maipo)"
+ID="rhel"
+ID_LIKE="fedora"
+VERSION_ID="7.2"
+PRETTY_NAME="Red Hat Enterprise Linux Server 7.2 (Maipo)"
+ANSI_COLOR="0;31"
+CPE_NAME="cpe:/o:redhat:enterprise_linux:7.2:GA:server"
+HOME_URL="https://www.redhat.com/"
+BUG_REPORT_URL="https://bugzilla.redhat.com/"
+
+REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 7"
+REDHAT_BUGZILLA_PRODUCT_VERSION=7.2
+REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
+REDHAT_SUPPORT_PRODUCT_VERSION="7.2"
+"""