From d479f3fc0c7587c5d7500a8a150a4dbff8573d6c Mon Sep 17 00:00:00 2001
From: Robbert van der Helm <mail@robbertvanderhelm.nl>
Date: Sat, 25 Jun 2022 15:45:43 +0200
Subject: [PATCH] [yabridgectl] Abort for dangerous ~/.vst/yabridge symlinks

If `~/.vst/yabridge` is a symlink to one of the directories contained
within yabridgectl's plugin locations, then weird things may happen.

Spotted in
https://github.com/robbert-vdh/yabridge/issues/185#issuecomment-1166274104.
---
 CHANGELOG.md                     |  6 +++++
 tools/yabridgectl/src/actions.rs | 42 ++++++++++++++++++++++++++++++--
 2 files changed, 46 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9c0c12c0..6ea8f5da 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,12 @@ Versioning](https://semver.org/spec/v2.0.0.html).
   locations. This normally would never happen, but it can happen if you manually
   extract a .zip file containing Windows plugins to those directories that was
   created on macOS. Don't ask me how or why.
+- Abort the `yabridgectl sync` process if `~/.vst/yabridge` or
+  `~/.vst3/yabridge` are symlinks to another directory, and that directory is
+  part of or contains one of yabridgectl's plugin search directories. This
+  prevents an edge cases where VST2 plugin .dll files could be replaced by
+  symlinks to themeselves if `~/.vst/yabridge` was a symlink to a VstPlugins
+  directory.
 - Don't panic when someone `yabridgectl add`'ed part of the contents of a
   Windows VST3 bundle. For the record, you really, really, _really_ shouldn't be
   doing this.
diff --git a/tools/yabridgectl/src/actions.rs b/tools/yabridgectl/src/actions.rs
index 848bc867..9ecdb140 100644
--- a/tools/yabridgectl/src/actions.rs
+++ b/tools/yabridgectl/src/actions.rs
@@ -261,6 +261,44 @@ pub fn do_sync(config: &mut Config, options: &SyncOptions) -> Result<()> {
         .search_directories()
         .context("Failure while searching for plugins")?;
 
+    // Before doing anything, make sure `~/.vst/yabridge` and `~/.vst3/yabridge` are not symlinks to
+    // one of the plugin directories. See
+    // https://github.com/robbert-vdh/yabridge/issues/185#issuecomment-1166274104.
+    let vst2_home = yabridge_vst2_home();
+    let vst3_home = yabridge_vst3_home();
+    if let Ok(canonical_vst2_home) = fs::canonicalize(&vst2_home) {
+        if canonical_vst2_home != vst2_home {
+            for plugin_dir in &config.plugin_dirs {
+                if let Ok(canonical_plugin_dir) = fs::canonicalize(&plugin_dir) {
+                    if canonical_plugin_dir.starts_with(&canonical_vst2_home) {
+                        anyhow::bail!(
+                            "'~/.vst/yabridge' is a symlink to '{}'. \
+                             This conflicts with '{}' from your plugin directories, so the syncing process will now be aborted.",
+                            canonical_vst2_home.display(),
+                            plugin_dir.display(),
+                        );
+                    }
+                }
+            }
+        }
+    }
+    if let Ok(canonical_vst3_home) = fs::canonicalize(&vst3_home) {
+        if canonical_vst3_home != vst3_home {
+            for plugin_dir in &config.plugin_dirs {
+                if let Ok(canonical_plugin_dir) = fs::canonicalize(&plugin_dir) {
+                    if canonical_plugin_dir.starts_with(&canonical_vst3_home) {
+                        anyhow::bail!(
+                            "'~/.vst3/yabridge' is a symlink to '{}'. \
+                             This conflicts with '{}' from your plugin directories, so the syncing process will now be aborted.",
+                            canonical_vst3_home.display(),
+                            plugin_dir.display(),
+                        );
+                    }
+                }
+            }
+        }
+    }
+
     // Keep track of some global statistics
     // The plugin files we installed. This tracks copies of/symlinks to `libabyrdge-*.so` managed.
     // by yabridgectl. This could be optimized a bit so we wouldn't have to track everything, but
@@ -537,7 +575,7 @@ pub fn do_sync(config: &mut Config, options: &SyncOptions) -> Result<()> {
     // regardless of the VST2 installation location setting so switching between the two modes and
     // then pruning works as expected.
     // TODO: Move this elsewhere
-    let centralized_vst2_files = WalkDir::new(yabridge_vst2_home())
+    let centralized_vst2_files = WalkDir::new(vst2_home)
         .follow_links(true)
         .same_file_system(true)
         .into_iter()
@@ -553,7 +591,7 @@ pub fn do_sync(config: &mut Config, options: &SyncOptions) -> Result<()> {
                 None
             }
         });
-    let installed_vst3_bundles = WalkDir::new(yabridge_vst3_home())
+    let installed_vst3_bundles = WalkDir::new(vst3_home)
         .follow_links(true)
         .same_file_system(true)
         .into_iter()