From 141aa9e5798562fc8802ba0d8bd016d972b256a9 Mon Sep 17 00:00:00 2001
From: sommerfe <sommerfe@NetBSD.org>
Date: Tue, 9 Feb 1999 05:15:45 +0000
Subject: [PATCH] Fix PR2429: catch doubly-applied patches which create new
 files.

---
 usr.bin/patch/common.h |  4 +++-
 usr.bin/patch/inp.c    |  9 +++++++--
 usr.bin/patch/pch.c    | 13 +++++++++----
 usr.bin/patch/util.c   |  9 ++++++---
 4 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/usr.bin/patch/common.h b/usr.bin/patch/common.h
index b1487794b7ea..9b1cfaa371ce 100644
--- a/usr.bin/patch/common.h
+++ b/usr.bin/patch/common.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: common.h,v 1.8 1998/02/22 13:33:48 christos Exp $	*/
+/*	$NetBSD: common.h,v 1.9 1999/02/09 05:15:45 sommerfe Exp $	*/
 
 #define DEBUGGING
 
@@ -110,6 +110,8 @@ EXT bool out_of_mem INIT(FALSE);	/* ran out of memory in plan a */
 EXT int filec INIT(0);			/* how many file arguments? */
 EXT char *filearg[MAXFILEC];
 EXT bool ok_to_create_file INIT(FALSE);
+EXT bool filename_is_dev_null INIT(FALSE);
+EXT bool old_file_is_dev_null INIT(FALSE);
 EXT char *bestguess INIT(Nullch);	/* guess at correct filename */
 
 EXT char *outname INIT(Nullch);
diff --git a/usr.bin/patch/inp.c b/usr.bin/patch/inp.c
index 8b977dc2b4ba..2273b3b6e8d6 100644
--- a/usr.bin/patch/inp.c
+++ b/usr.bin/patch/inp.c
@@ -1,7 +1,7 @@
-/*	$NetBSD: inp.c,v 1.5 1998/11/06 22:40:13 christos Exp $	*/
+/*	$NetBSD: inp.c,v 1.6 1999/02/09 05:15:45 sommerfe Exp $	*/
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: inp.c,v 1.5 1998/11/06 22:40:13 christos Exp $");
+__RCSID("$NetBSD: inp.c,v 1.6 1999/02/09 05:15:45 sommerfe Exp $");
 #endif /* not lint */
 
 #include "EXTERN.h"
@@ -145,6 +145,11 @@ char *filename;
 		fatal3("can't check out file %s from %s\n", filename, cs);
 	}
     }
+    if (old_file_is_dev_null && ok_to_create_file && (filestat.st_size != 0)) {
+	fatal2("patch creates new file but existing file %s not empty\n",
+	       filename);
+    }
+
     filemode = filestat.st_mode;
     if (!S_ISREG(filemode))
 	fatal2("%s is not a normal file--can't patch\n", filename);
diff --git a/usr.bin/patch/pch.c b/usr.bin/patch/pch.c
index 24bdf23646b4..ebec9a0708ef 100644
--- a/usr.bin/patch/pch.c
+++ b/usr.bin/patch/pch.c
@@ -1,7 +1,7 @@
-/*	$NetBSD: pch.c,v 1.6 1998/11/06 22:40:13 christos Exp $	*/
+/*	$NetBSD: pch.c,v 1.7 1999/02/09 05:15:45 sommerfe Exp $	*/
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: pch.c,v 1.6 1998/11/06 22:40:13 christos Exp $");
+__RCSID("$NetBSD: pch.c,v 1.7 1999/02/09 05:15:45 sommerfe Exp $");
 #endif /* not lint */
 
 #include "EXTERN.h"
@@ -204,6 +204,7 @@ intuit_diff_type()
     bool no_filearg = (filearg[0] == Nullch);
 
     ok_to_create_file = FALSE;
+    old_file_is_dev_null = FALSE;
     Fseek(pfp, p_base, 0);
     p_input_line = p_bline - 1;
     for (;;) {
@@ -307,8 +308,10 @@ intuit_diff_type()
     if (no_filearg) {
 	if (indtmp != Nullch)
 	    indname = fetchname(indtmp, strippath, ok_to_create_file);
-	if (oldtmp != Nullch)
+	if (oldtmp != Nullch) {
 	    oldname = fetchname(oldtmp, strippath, ok_to_create_file);
+	    old_file_is_dev_null = filename_is_dev_null;
+	}
 	if (newtmp != Nullch)
 	    newname = fetchname(newtmp, strippath, ok_to_create_file);
 	if (oldname && newname) {
@@ -333,8 +336,10 @@ intuit_diff_type()
     else if (indtmp != Nullch)
 	bestguess = fetchname(indtmp, strippath, TRUE);
     else {
-	if (oldtmp != Nullch)
+        if (oldtmp != Nullch) {
 	    oldname = fetchname(oldtmp, strippath, TRUE);
+	    old_file_is_dev_null = filename_is_dev_null;
+	}
 	if (newtmp != Nullch)
 	    newname = fetchname(newtmp, strippath, TRUE);
 	if (oldname && newname) {
diff --git a/usr.bin/patch/util.c b/usr.bin/patch/util.c
index f51c59f93cd9..5c15ffcc3c78 100644
--- a/usr.bin/patch/util.c
+++ b/usr.bin/patch/util.c
@@ -1,7 +1,7 @@
-/*	$NetBSD: util.c,v 1.6 1998/11/06 22:40:13 christos Exp $	*/
+/*	$NetBSD: util.c,v 1.7 1999/02/09 05:15:45 sommerfe Exp $	*/
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: util.c,v 1.6 1998/11/06 22:40:13 christos Exp $");
+__RCSID("$NetBSD: util.c,v 1.7 1999/02/09 05:15:45 sommerfe Exp $");
 #endif /* not lint */
 
 #include "EXTERN.h"
@@ -455,8 +455,11 @@ int assume_exists;
     if (debug & 128)
 	say4("fetchname %s %d %d\n",at,strip_leading,assume_exists);
 #endif
-    if (strnEQ(at, "/dev/null", 9))	/* so files can be created by diffing */
+    filename_is_dev_null = FALSE;
+    if (strnEQ(at, "/dev/null", 9)) {	/* so files can be created by diffing */
+        filename_is_dev_null = TRUE;
 	return Nullch;			/*   against /dev/null. */
+    }
     name = fullname = t = savestr(at);
 
     /* Strip off up to `sleading' leading slashes and null terminate.  */