cli: config: do not overwrite symlinks when saving config file

Use realpath to canonicalize the config path before writing.

Previously 'notmuch setup' and 'notmuch config set' overwrote the
config file even if it was a symbolic link.

1 files changed, 20 insertions, 4 deletions

diff --git a/notmuch-config.c b/notmuch-config.c
index 66a1cdfb..d9c2eb3f 100644
--- a/notmuch-config.c
+++ b/notmuch-config.c
@@ -444,7 +444,7 @@ int
 notmuch_config_save (notmuch_config_t *config)
 {
     size_t length;
-    char *data;
+    char *data, *filename;
     GError *error = NULL;
 
     data = g_key_file_to_data (config->key_file, &length, NULL);
@@ -453,14 +453,30 @@ notmuch_config_save (notmuch_config_t *config)
 	return 1;
     }
 
-    if (! g_file_set_contents (config->filename, data, length, &error)) {
-	fprintf (stderr, "Error saving configuration to %s: %s\n",
-		 config->filename, error->message);
+    /* Try not to overwrite symlinks. */
+    filename = realpath (config->filename, NULL);
+    if (! filename) {
+	fprintf (stderr, "Error canonicalizing %s: %s\n", config->filename,
+		 strerror (errno));
+	g_free (data);
+	return 1;
+    }
+
+    if (! g_file_set_contents (filename, data, length, &error)) {
+	if (strcmp (filename, config->filename) != 0) {
+	    fprintf (stderr, "Error saving configuration to %s (-> %s): %s\n",
+		     config->filename, filename, error->message);
+	} else {
+	    fprintf (stderr, "Error saving configuration to %s: %s\n",
+		     filename, error->message);
+	}
 	g_error_free (error);
+	free (filename);
 	g_free (data);
 	return 1;
     }
 
+    free (filename);
     g_free (data);
     return 0;
 }