scubainit: Don't create home directory if it already exists

The mkdir_p is harmless, but the chmod/chown might actually affect the
invoking user's home directory if .scuba.yml exists there.

Note that the chown is probably harmless because it would be chowning to
the same user. But it's better to not mess with anything.

scubainit/scubainit.c

@@ -365,6 +365,19 @@ mkdir_p(const char *path)
 static int
 make_homedir(const char *path, unsigned int uid, unsigned int gid)
 {
+    struct stat st;
+
+    /* See if the home directory already exists */
+    if (stat(path, &st) == 0) {
+        verbose("Homedir %s already exists\n", path);
+        return 0;
+    }
+    else if (errno != ENOENT) {
+        errmsg("Failed to stat %s: %m\n", path);
+        return -1;
+    }
+
+    /* Create the home directory */
     if (mkdir_p(path) != 0) {
         errmsg("Failed to create %s: %m\n", path);
         return -1;
@@ -377,6 +390,8 @@ make_homedir(const char *path, unsigned int uid, unsigned int gid)
         errmsg("Failed to chown %s: %m\n", path);
         return -1;
     }
+
+    verbose("Created homedir %s\n", path);
     return 0;
 }