environ: Allow NULL envp

https://bugzilla.gnome.org/show_bug.cgi?id=676397

glib/genviron.c

@@ -54,6 +54,9 @@ g_environ_find (gchar       **envp,
 {
   gint len, i;
 
+  if (envp == NULL)
+    return -1;
+
   len = strlen (variable);
 
   for (i = 0; envp[i]; i++)
@@ -68,8 +71,9 @@ g_environ_find (gchar       **envp,
 
 /**
  * g_environ_getenv:
- * @envp: (array zero-terminated=1) (transfer none): an environment
+ * @envp: (allow-none) (array zero-terminated=1) (transfer none): an environment
- *     list (eg, as returned from g_get_environ())
+ *     list (eg, as returned from g_get_environ()), or %NULL
+ *     for an empty environment list
  * @variable: the environment variable to get, in the GLib file name
  *     encoding
  *
@@ -96,7 +100,6 @@ g_environ_getenv (gchar       **envp,
 {
   gint index;
 
-  g_return_val_if_fail (envp != NULL, NULL);
   g_return_val_if_fail (variable != NULL, NULL);
 
   index = g_environ_find (envp, variable);
@@ -108,8 +111,9 @@ g_environ_getenv (gchar       **envp,
 
 /**
  * g_environ_setenv:
- * @envp: (array zero-terminated=1) (transfer full): an environment
+ * @envp: (allow-none) (array zero-terminated=1) (transfer full): an environment
- *     list that can be freed using g_strfreev() (e.g., as returned from g_get_environ())
+ *     list that can be freed using g_strfreev() (e.g., as returned from g_get_environ()), or %NULL
+ *     for an empty environment list
  * @variable: the environment variable to set, must not contain '='
  * @value: the value for to set the variable to
  * @overwrite: whether to change the variable if it already exists
@@ -134,7 +138,6 @@ g_environ_setenv (gchar       **envp,
 {
   gint index;
 
-  g_return_val_if_fail (envp != NULL, NULL);
   g_return_val_if_fail (variable != NULL, NULL);
   g_return_val_if_fail (strchr (variable, '=') == NULL, NULL);
 
@@ -151,7 +154,7 @@ g_environ_setenv (gchar       **envp,
     {
       gint length;
 
-      length = g_strv_length (envp);
+      length = envp ? g_strv_length (envp) : 0;
       envp = g_renew (gchar *, envp, length + 2);
       envp[length] = g_strdup_printf ("%s=%s", variable, value);
       envp[length + 1] = NULL;
@@ -191,14 +194,18 @@ g_environ_unsetenv_internal (gchar        **envp,
     }
   *f = NULL;
 
+  if (free_value_and_realloc)
+    return g_renew (gchar *, envp, envc + 1);
+  else
     return envp;
 }
 
 
 /**
  * g_environ_unsetenv:
- * @envp: (array zero-terminated=1) (transfer full): an environment
+ * @envp: (allow-none) (array zero-terminated=1) (transfer full): an environment
- *     list that can be freed using g_strfreev() (e.g., as returned from g_get_environ())
+ *     list that can be freed using g_strfreev() (e.g., as returned from g_get_environ()), 
+ *     or %NULL for an empty environment list
  * @variable: the environment variable to remove, must not contain '='
  *
  * Removes the environment variable @variable from the provided
@@ -213,10 +220,12 @@ gchar **
 g_environ_unsetenv (gchar       **envp,
                     const gchar  *variable)
 {
-  g_return_val_if_fail (envp != NULL, NULL);
   g_return_val_if_fail (variable != NULL, NULL);
   g_return_val_if_fail (strchr (variable, '=') == NULL, NULL);
 
+  if (envp == NULL)
+    return NULL;
+
   return g_environ_unsetenv_internal (envp, variable, TRUE);
 }
 

glib/tests/environment.c

@@ -96,6 +96,25 @@ test_environ_array (void)
   g_strfreev (env);
 }
 
+static void
+test_environ_null (void)
+{
+  gchar **env;
+  const gchar *value;
+
+  env = NULL;
+
+  value = g_environ_getenv (env, "foo");
+  g_assert (value == NULL);
+
+  env = g_environ_setenv (NULL, "foo", "bar", TRUE);
+  g_assert (env != NULL);
+  g_strfreev (env);
+
+  env = g_environ_unsetenv (NULL, "foo");
+  g_assert (env == NULL);
+}
+
 int
 main (int argc, char **argv)
 {
@@ -104,6 +123,7 @@ main (int argc, char **argv)
   g_test_add_func ("/environ/listenv", test_listenv);
   g_test_add_func ("/environ/setenv", test_setenv);
   g_test_add_func ("/environ/array", test_environ_array);
+  g_test_add_func ("/environ/null", test_environ_null);
 
   return g_test_run ();
 }