Fix bug where insert-file-contents closes a file twice.

* fileio.c (close_file_unwind): Don't close if FD is negative;
this can happen when unwinding a zapped file descriptor.
(Finsert_file_contents): Unwind-protect the fd before the point marker,
in case Emacs runs out of memory between the two unwind-protects.
Don't trash errno when closing FD.
Zap the FD in the specpdl when closing it, instead of deferring
the removal of the unwind-protect; this fixes a bug where a child
function unwinds the stack past us.

Fixes: debbugs:14839

1 files changed, 10 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 8474e8aa5e4..ab90682aa67 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,15 @@
 2013-07-16  Paul Eggert  <eggert@cs.ucla.edu>
 
+        Fix bug where Emacs tries to close a file twice (Bug#14839).
+        * fileio.c (close_file_unwind): Don't close if FD is negative;
+        this can happen when unwinding a zapped file descriptor.
+        (Finsert_file_contents): Unwind-protect the fd before the point marker,
+        in case Emacs runs out of memory between the two unwind-protects.
+        Don't trash errno when closing FD.
+        Zap the FD in the specpdl when closing it, instead of deferring
+        the removal of the unwind-protect; this fixes a bug where a child
+        function unwinds the stack past us.
+
         New unwind-protect flavors to better type-check C callbacks.
         This also lessens the need to write wrappers for callbacks,
         and the need for make_save_pointer.