This is a backport of the fix itself.

From 768901548e280726f160a1da4434f3fde8f9921a Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@fb.com>
Date: Sat, 9 May 2015 19:47:08 -0700
Subject: [PATCH 84/92] sed -i: don't leave behind a temporary sedXXXXXX file

For example, running a command like "sed -i s//b/ F" would fail
to remove a temporary file named sedXXXXXX (for random XXXXXX)
in the directory alongside F.
* sed/sed.c (G_file_to_unlink): New global.
(register_cleanup_file, cancel_cleanup, cleanup): New functions.
(main): Call atexit.
* sed/execute.c (open_next_file): Register for unlink.
(closedown): Call cancel_cleanup right after the rename.
* sed/sed.h: Declare two of the new functions.
* NEWS (Bug fixes): Mention it.
* testsuite/temp-file-cleanup.sh: New file.  Test for this.
* testsuite/Makefile.am (T): Add it.
Reported by David Jones in http://bugs.gnu.org/20002.
---
 NEWS                           |  4 ++++
 sed/execute.c                  |  2 ++
 sed/sed.c                      | 35 ++++++++++++++++++++++++++++++++++-
 sed/sed.h                      |  2 ++
 testsuite/Makefile.am          |  3 ++-
 testsuite/temp-file-cleanup.sh | 38 ++++++++++++++++++++++++++++++++++++++
 6 files changed, 82 insertions(+), 2 deletions(-)
 create mode 100755 testsuite/temp-file-cleanup.sh

Index: sed-4.2.2/sed/execute.c
===================================================================
--- sed-4.2.2.orig/sed/execute.c
+++ sed-4.2.2/sed/execute.c
@@ -656,6 +656,7 @@ open_next_file(name, input)
 
       output_file.fp = ck_mkstemp (&input->out_file_name, tmpdir, "sed",
 				   write_mode);
+      register_cleanup_file (input->out_file_name);
       output_file.missing_newline = false;
       free (tmpdir);
 
@@ -713,6 +714,7 @@ closedown(input)
 	}
 
       ck_rename (input->out_file_name, target_name, input->out_file_name);
+      cancel_cleanup ();
       free (input->out_file_name);
     }
   else
Index: sed-4.2.2/sed/sed.c
===================================================================
--- sed-4.2.2.orig/sed/sed.c
+++ sed-4.2.2/sed/sed.c
@@ -69,6 +69,35 @@ countT lcmd_out_line_len = 70;
 /* The complete compiled SED program that we are going to run: */
 static struct vector *the_program = NULL;
 
+/* When we've created a temporary for an in-place update,
+   we may have to exit before the rename.  This is the name
+   of the temporary that we'll have to unlink via an atexit-
+   registered cleanup function.  */
+static char const *G_file_to_unlink;
+
+/* When exiting between temporary file creation and the rename
+   associated with a sed -i invocation, remove that file.  */
+static void
+cleanup (void)
+{
+  if (G_file_to_unlink)
+    unlink (G_file_to_unlink);
+}
+
+/* Note that FILE must be removed upon exit.  */
+void
+register_cleanup_file (char const *file)
+{
+  G_file_to_unlink = file;
+}
+
+/* Clear the global file-to-unlink global.  */
+void
+cancel_cleanup (void)
+{
+  G_file_to_unlink = NULL;
+}
+
 static void usage (int);
 static void
 contact(errmsg)
@@ -200,6 +229,10 @@ main(argc, argv)
 #endif
   initialize_mbcs ();
 
+  /* Arrange to remove any un-renamed temporary file,
+     upon premature exit.  */
+  atexit (cleanup);
+
 #if ENABLE_NLS
 
   /* Tell program which translations to use and where to find.  */
Index: sed-4.2.2/sed/sed.h
===================================================================
--- sed-4.2.2.orig/sed/sed.h
+++ sed-4.2.2/sed/sed.h
@@ -262,4 +262,6 @@ extern bool is_utf8;
 
 extern int brlen (int ch, mbstate_t *ps);
 extern void initialize_mbcs (void);
+extern void register_cleanup_file (char const *file);
+extern void cancel_cleanup (void);