3 files changed, 20 insertions, 1 deletions
diff --git a/src/libutil/tests/tests.cc b/src/libutil/tests/tests.cc
index 250e83a38..f3c1e8248 100644
--- a/src/libutil/tests/tests.cc
+++ b/src/libutil/tests/tests.cc
@@ -202,7 +202,7 @@ namespace nix {
     }
 
     TEST(pathExists, bogusPathDoesNotExist) {
-        ASSERT_FALSE(pathExists("/home/schnitzel/darmstadt/pommes"));
+        ASSERT_FALSE(pathExists("/schnitzel/darmstadt/pommes"));
     }
 
     /* ----------------------------------------------------------------------------
diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index 3a8309149..aa0a154fd 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -266,6 +266,17 @@ bool pathExists(const Path & path)
     return false;
 }
 
+bool pathAccessible(const Path & path)
+{
+    try {
+        return pathExists(path);
+    } catch (SysError & e) {
+        // swallow EPERM
+        if (e.errNo == EPERM) return false;
+        throw;
+    }
+}
+
 
 Path readLink(const Path & path)
 {
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index a7907cd14..00fcb9b79 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -121,6 +121,14 @@ struct stat lstat(const Path & path);
 bool pathExists(const Path & path);
 
 /**
+ * A version of pathExists that returns false on a permission error.
+ * Useful for inferring default paths across directories that might not
+ * be readable.
+ * @return true iff the given path can be accessed and exists
+ */
+bool pathAccessible(const Path & path);
+
+/**
  * Read the contents (target) of a symbolic link.  The result is not
  * in any way canonicalised.
  */