[glib/wip/oholy/fix-trash-symlink: 3/3] glocalfile: Use MAXSYMLINKS when following symlinks

[Ondrej Holy <oholy src gnome org>]

commit a56b9cc6b2ea0eae341563d7273cbaa7ac1b39f5
Author: Ondrej Holy <oholy redhat com>
Date:   Fri Sep 21 16:12:51 2018 +0200

    glocalfile: Use MAXSYMLINKS when following symlinks
    
    Currently, readlink() is used only 12 times when expanding symlinks.
    However, kernel uses 40 for this purpose and it is defined as MAXSYMLINKS.
    Use that constant if available, or 40. See:
    https://github.com/torvalds/linux/include/linux/namei.h.

 gio/glocalfile.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/gio/glocalfile.c b/gio/glocalfile.c
index a547bcda0..064755981 100644
--- a/gio/glocalfile.c
+++ b/gio/glocalfile.c
@@ -1610,7 +1610,15 @@ expand_symlinks (const char *path,
         }
 
       num_recursions++;
-      if (num_recursions > 12)
+
+#ifdef MAXSYMLINKS
+      if (num_recursions > MAXSYMLINKS)
+#else
+      /* 40 is used in kernel sources currently:
+       * https://github.com/torvalds/linux/include/linux/namei.h
+       */
+      if (num_recursions > 40)
+#endif
         {
           g_free (target);
           return NULL;