Find Ghidra installed from a Linux package

Linux packages put Ghidra in /opt/ghidra (Arch and its derivatives) or /usr/share/ghidra (Debian, Kali) with only a start script on PATH, so Deep mode said Ghidra wasn't there (#85). The engine table lists both folders and the Ghidra lookup falls back to them.

crates/engines/src/ghidra/get.rs

@@ -26,7 +26,7 @@ pub fn can_install() -> bool {
 }
 
 /// Ghidra's headless launcher: in the folder the person picked (Ghidra's own folder, or one that
-/// holds it), then the managed install, then PATH.
+/// holds it), then the managed install, then PATH, then where system packages put it.
 pub fn headless(install_dir: Option<&Path>, store: &Path) -> Option<PathBuf> {
     if let Some(dir) = install_dir {
         if dir.is_file() {
@@ -36,7 +36,9 @@ pub fn headless(install_dir: Option<&Path>, store: &Path) -> Option<PathBuf> {
             return Some(p);
         }
     }
-    in_child(&store.join(ID), launcher).or_else(|| crate::find_on_path(&["analyzeHeadless.bat", "analyzeHeadless"]))
+    in_child(&store.join(ID), launcher)
+        .or_else(|| crate::find_on_path(&["analyzeHeadless.bat", "analyzeHeadless"]))
+        .or_else(|| crate::well_known(ID).into_iter().find(|p| p.is_file()))
 }
 
 /// The Java runtime to run Ghidra with: the one the person set, else the managed one. `None` lets
@@ -150,7 +152,9 @@ mod tests {
         let d = tempfile::tempdir().unwrap();
         let store = d.path().join("store");
         let exe = if cfg!(windows) { "analyzeHeadless.bat" } else { "analyzeHeadless" };
-        assert!(headless(None, &store).is_none() || crate::find_on_path(&[exe]).is_some());
+        // None, unless this computer has Ghidra on PATH or from a system package.
+        let installed = crate::find_on_path(&[exe]).is_some() || crate::well_known(ID).iter().any(|p| p.is_file());
+        assert!(headless(None, &store).is_none() || installed);
         // The managed install: the zip's own top folder under <store>/ghidra.
         let managed = store.join("ghidra/ghidra_12.1.4_PUBLIC/support").join(exe);
         touch(&managed);

crates/engines/src/lib.rs

@@ -82,7 +82,7 @@ fn in_managed(dir: &Path, exes: &[&str]) -> Option<PathBuf> {
 }
 
 /// Standard install locations for programs that don't put themselves on PATH (browsers on
-/// Windows and macOS), most common first.
+/// Windows and macOS, Ghidra from Linux packages), most common first.
 pub fn well_known(id: &str) -> Vec<PathBuf> {
     engine(id).map(ExternalEngine::known_install_paths).unwrap_or_default()
 }
@@ -135,7 +135,9 @@ mod tests {
         // Nothing but folders: still none, not a panic.
         let empty = tempfile::tempdir().unwrap();
         std::fs::create_dir_all(empty.path().join("ghidra").join("ghidra_12.1.4_PUBLIC")).unwrap();
-        assert!(locate("ghidra", &NoOverrides, empty.path()).is_none());
+        // (Unless this computer has Ghidra on PATH or from a system package.)
+        let installed = find_on_path(&[exe]).is_some() || well_known("ghidra").iter().any(|p| p.is_file());
+        assert!(locate("ghidra", &NoOverrides, empty.path()).is_none() || installed);
     }
 
     #[test]
@@ -146,5 +148,12 @@ mod tests {
             assert!(paths.iter().any(|p| p.to_string_lossy().contains("Chrome")));
             assert!(paths.iter().any(|p| p.to_string_lossy().contains("Edge")));
         }
+        // #85: Linux packages put Ghidra in its own folder with only a start script on PATH.
+        let ghidra = well_known("ghidra");
+        if cfg!(target_os = "linux") {
+            assert_eq!(ghidra, [PathBuf::from("/opt/ghidra/support/analyzeHeadless"), PathBuf::from("/usr/share/ghidra/support/analyzeHeadless")]);
+        } else {
+            assert!(ghidra.is_empty());
+        }
     }
 }

crates/engines/src/table.rs

@@ -144,8 +144,16 @@ const fn mac(base: Base, rel: &'static str) -> KnownPath {
     KnownPath { os: "macos", base, rel }
 }
 
+const fn linux(dir: &'static str, rel: &'static str) -> KnownPath {
+    KnownPath { os: "linux", base: Base::Dir(dir), rel }
+}
+
 const NO_PATHS: &[KnownPath] = &[];
 
+/// Linux packages put Ghidra in a folder of its own and only a start script on PATH (`/usr/bin/ghidra`):
+/// Arch and its derivatives in `/opt/ghidra`, Debian and Kali in `/usr/share/ghidra` (#85).
+const GHIDRA_PATHS: &[KnownPath] = &[linux("/opt/ghidra", "support/analyzeHeadless"), linux("/usr/share/ghidra", "support/analyzeHeadless")];
+
 /// Browsers on Windows and macOS rarely put themselves on PATH.
 const CHROMIUM_PATHS: &[KnownPath] = &[
     win("ProgramFiles", "Google/Chrome/Application/chrome.exe"),
@@ -322,7 +330,7 @@ pub const ENGINES: &[ExternalEngine] = &[
         needed_for: "Deep mode: richer decompiled code",
         exes: &["analyzeHeadless"],
         exes_windows: &["analyzeHeadless.bat"],
-        known_paths: NO_PATHS,
+        known_paths: GHIDRA_PATHS,
         path_setting: false,
         install: Install::Guided { pins: GHIDRA_PINS, how: GHIDRA_SETUP },
     },