Fix sandboxing on OS X

The main issue was resources_dir_path. Every time it was called it would start from the executable's path and walk up the hierarchy to find a directory named "resources". The sandbox was granted permission to read from the found resources dir, but after the sandbox had been activated resources_dir_path would again start from the executable's path and try to find the resources dir. It would then fail with "Operation not permitted" when trying to canonicalize the path because it didn't have permissions to read metadata under ./target.

To fix this the resources dir path is now cached between resources_dir_path calls.

components/compositing/sandboxing.rs

@@ -16,7 +16,9 @@ pub fn content_process_sandbox_profile() -> Profile {
         Operation::FileReadAll(PathPattern::Subpath(PathBuf::from("/Library/Fonts"))),
         Operation::FileReadAll(PathPattern::Subpath(PathBuf::from("/System/Library/Fonts"))),
         Operation::FileReadAll(PathPattern::Subpath(PathBuf::from(
-                    "/System/Library/Frameworks/ApplicationServices.framework/"))),
+                    "/System/Library/Frameworks/ApplicationServices.framework"))),
+        Operation::FileReadAll(PathPattern::Subpath(PathBuf::from(
+                    "/System/Library/Frameworks/CoreGraphics.framework"))),
         Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/"))),
         Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/Library"))),
         Operation::FileReadMetadata(PathPattern::Literal(PathBuf::from("/System"))),

components/servo/lib.rs

@@ -275,7 +275,8 @@ pub unsafe extern fn __errno_location() -> *mut i32 {
 
 #[cfg(not(target_os = "windows"))]
 fn create_sandbox() {
-    ChildSandbox::new(sandboxing::content_process_sandbox_profile()).activate().unwrap();
+    ChildSandbox::new(sandboxing::content_process_sandbox_profile()).activate()
+        .expect("Failed to activate sandbox!");
 }
 
 #[cfg(target_os = "windows")]

components/util/resource_files.rs

@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+use std::env;
 use std::fs::File;
 use std::io::{self, Read};
 use std::path::PathBuf;
@@ -25,35 +26,35 @@ pub fn resources_dir_path() -> PathBuf {
 
 #[cfg(not(target_os = "android"))]
 pub fn resources_dir_path() -> PathBuf {
-    use std::env;
+    let mut dir = CMD_RESOURCE_DIR.lock().unwrap();
+
+    if let Some(ref path) = *dir {
+        return PathBuf::from(path);
+    }
 
-    match *CMD_RESOURCE_DIR.lock().unwrap() {
-        Some(ref path) => PathBuf::from(path),
-        None => {
-            // FIXME: Find a way to not rely on the executable being
-            // under `<servo source>[/$target_triple]/target/debug`
-            // or `<servo source>[/$target_triple]/target/release`.
-            let mut path = env::current_exe().expect("can't get exe path");
-            // Follow symlink
-            path = path.canonicalize().expect("path does not exist");
+    // FIXME: Find a way to not rely on the executable being
+    // under `<servo source>[/$target_triple]/target/debug`
+    // or `<servo source>[/$target_triple]/target/release`.
+    let mut path = env::current_exe().expect("can't get exe path");
+    // Follow symlink
+    path = path.canonicalize().expect("path does not exist");
+    path.pop();
+    path.push("resources");
+    if !path.is_dir() {   // resources dir not in same dir as exe?
+        // exe is probably in target/{debug,release} so we need to go back to topdir
+        path.pop();
+        path.pop();
+        path.pop();
+        path.push("resources");
+        if !path.is_dir() {
+            // exe is probably in target/$target_triple/{debug,release} so go back one more
+            path.pop();
             path.pop();
             path.push("resources");
-            if !path.is_dir() {   // resources dir not in same dir as exe?
-                // exe is probably in target/{debug,release} so we need to go back to topdir
-                path.pop();
-                path.pop();
-                path.pop();
-                path.push("resources");
-                if !path.is_dir() {
-                    // exe is probably in target/$target_triple/{debug,release} so go back one more
-                    path.pop();
-                    path.pop();
-                    path.push("resources");
-                }
-            }
-            path
         }
     }
+    *dir = Some(path.to_str().unwrap().to_owned());
+    path
 }
 
 pub fn read_resource_file(relative_path_components: &[&str]) -> io::Result<Vec<u8>> {