From 8042ac5131ec296ae4c4c5250810203056555102 Mon Sep 17 00:00:00 2001
From: Ana Hobden <operator@hoverbear.org>
Date: Wed, 1 Feb 2023 10:40:56 -0800
Subject: [PATCH] Add plist use to the CreateFstabEntry action (#221)

---
 Cargo.lock                              |  3 ++
 Cargo.toml                              |  2 +-
 src/action/darwin/create_fstab_entry.rs | 54 +++++++------------------
 3 files changed, 18 insertions(+), 41 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 6c4fd53..cc623d5 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1868,6 +1868,9 @@ name = "uuid"
 version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "422ee0de9031b5b948b97a8fc04e3aa35230001a722ddd27943e0be31564ce4c"
+dependencies = [
+ "serde",
+]
 
 [[package]]
 name = "valuable"
diff --git a/Cargo.toml b/Cargo.toml
index f9e3bb5..6e7a573 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -52,7 +52,7 @@ dyn-clone = { version = "1.0.9", default-features = false }
 rand = { version = "0.8.5", default-features = false, features = [ "std", "std_rng" ] }
 semver = { version = "1.0.14", default-features = false, features = ["serde", "std"] }
 term = { version = "0.7.0", default-features = false }
-uuid = "1.2.2"
+uuid = { version = "1.2.2", features = ["serde"] }
 
 [dev-dependencies]
 eyre = { version = "0.6.8", default-features = false, features = [ "track-caller" ] }
diff --git a/src/action/darwin/create_fstab_entry.rs b/src/action/darwin/create_fstab_entry.rs
index 5fc2184..240c5b1 100644
--- a/src/action/darwin/create_fstab_entry.rs
+++ b/src/action/darwin/create_fstab_entry.rs
@@ -6,9 +6,9 @@ use crate::{
     execute_command,
 };
 use rand::Rng;
+use serde::Deserialize;
 use std::{
     io::SeekFrom,
-    os::unix::prelude::PermissionsExt,
     path::{Path, PathBuf},
     str::FromStr,
 };
@@ -82,13 +82,7 @@ impl Action for CreateFstabEntry {
     async fn execute(&mut self) -> Result<(), ActionError> {
         let Self { apfs_volume_label } = self;
         let fstab_path = Path::new(FSTAB_PATH);
-        let uuid = get_uuid_for_label(&apfs_volume_label)
-            .await?
-            .ok_or_else(|| {
-                ActionError::Custom(Box::new(CreateFstabEntryError::NoVolume(
-                    apfs_volume_label.clone(),
-                )))
-            })?;
+        let uuid = get_uuid_for_label(&apfs_volume_label).await?;
         let fstab_entry = fstab_entry(&uuid, apfs_volume_label);
 
         let mut fstab = tokio::fs::OpenOptions::new()
@@ -133,13 +127,7 @@ impl Action for CreateFstabEntry {
     async fn revert(&mut self) -> Result<(), ActionError> {
         let Self { apfs_volume_label } = self;
         let fstab_path = Path::new(FSTAB_PATH);
-        let uuid = get_uuid_for_label(&apfs_volume_label)
-            .await?
-            .ok_or_else(|| {
-                ActionError::Custom(Box::new(CreateFstabEntryError::NoVolume(
-                    apfs_volume_label.clone(),
-                )))
-            })?;
+        let uuid = get_uuid_for_label(&apfs_volume_label).await?;
         let fstab_entry = fstab_entry(&uuid, apfs_volume_label);
 
         let mut file = OpenOptions::new()
@@ -177,11 +165,12 @@ impl Action for CreateFstabEntry {
     }
 }
 
-async fn get_uuid_for_label(apfs_volume_label: &str) -> Result<Option<Uuid>, ActionError> {
+async fn get_uuid_for_label(apfs_volume_label: &str) -> Result<Uuid, ActionError> {
     let output = execute_command(
         Command::new("/usr/sbin/diskutil")
             .process_group(0)
             .arg("info")
+            .arg("-plist")
             .arg(apfs_volume_label)
             .stdin(std::process::Stdio::null())
             .stdout(std::process::Stdio::piped()),
@@ -189,27 +178,9 @@ async fn get_uuid_for_label(apfs_volume_label: &str) -> Result<Option<Uuid>, Act
     .await
     .map_err(|e| ActionError::Command(e))?;
 
-    let stdout = String::from_utf8(output.stdout)?;
+    let parsed: DiskUtilApfsInfoOutput = plist::from_bytes(&output.stdout)?;
 
-    let mut found = None;
-    for line in stdout.lines() {
-        let prefix = "Volume UUID:";
-        let trimmed = line.trim();
-        if let Some(index) = trimmed.find(prefix) {
-            let maybe_uuid = trimmed[(index + prefix.len())..].trim();
-            let uuid = Uuid::parse_str(maybe_uuid).map_err(|err| {
-                ActionError::Custom(Box::new(CreateFstabEntryError::Uuid(
-                    maybe_uuid.to_string(),
-                    err,
-                )))
-            })?;
-
-            found = Some(uuid);
-            break;
-        }
-    }
-
-    Ok(found)
+    Ok(parsed.volume_uuid)
 }
 
 fn fstab_prelude_comment(apfs_volume_label: &str) -> String {
@@ -228,10 +199,13 @@ fn fstab_entry(uuid: &Uuid, apfs_volume_label: &str) -> String {
 
 #[derive(thiserror::Error, Debug)]
 pub enum CreateFstabEntryError {
-    #[error("UUID error: {0}")]
-    Uuid(String, #[source] uuid::Error),
-    #[error("No volume labelled `{0}` present, cannot get UUID to add to /etc/fstab")]
-    NoVolume(String),
     #[error("An `/etc/fstab` entry for the volume labelled `{0}` already exists. If a Nix Store already exists it may need to be deleted with `diskutil apfs deleteVolume \"{0}\") and should be removed from `/etc/fstab`")]
     EntryExists(String),
 }
+
+#[derive(Deserialize, Clone, Debug)]
+#[serde(rename_all = "PascalCase")]
+struct DiskUtilApfsInfoOutput {
+    #[serde(rename = "VolumeUUID")]
+    volume_uuid: Uuid,
+}