[glib/wip/oholy/fix-trash-symlink: 5/5] glocalfile: Use MAXSYMLINKS when following symlinks

[Ondrej Holy <oholy src gnome org>]

commit a55606216a9ed4eafe89868d4fd6ba8a25660332
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 06d1ae58e..c3508ac03 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;