[src/trunk]: src/usr.bin/compress uncompress: if the source doesn't exist, do...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/75b591890195
branches:  trunk
changeset: 366358:75b591890195
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun May 22 21:16:50 2022 +0000

description:
uncompress: if the source doesn't exist, don't touch the target

Fixes part of PR bin/19722, reported by Giorgos Keramidas.

diffstat:

 tests/usr.bin/compress/t_pr_19722.sh |  16 ++++++++++------
 usr.bin/compress/compress.c          |  12 ++++++------
 2 files changed, 16 insertions(+), 12 deletions(-)

diffs (88 lines):

diff -r 90c73efb29ea -r 75b591890195 tests/usr.bin/compress/t_pr_19722.sh
--- a/tests/usr.bin/compress/t_pr_19722.sh      Sun May 22 20:49:12 2022 +0000
+++ b/tests/usr.bin/compress/t_pr_19722.sh      Sun May 22 21:16:50 2022 +0000
@@ -1,4 +1,4 @@
-#      $NetBSD: t_pr_19722.sh,v 1.2 2022/05/22 20:49:12 rillig Exp $
+#      $NetBSD: t_pr_19722.sh,v 1.3 2022/05/22 21:16:50 rillig Exp $
 #
 # Copyright (c) 2022 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -92,15 +92,17 @@
 uncompress_no_source_no_target_body()
 {
        # PR 19722: uncompressing a missing source creates empty target
+       #
+       # Before compress.c 1.28 from 2022-05-22, uncompress created an empty
+       # target file and didn't clean it up.
 
        atf_check \
            -s 'not-exit:0' \
            -e 'inline:uncompress: file.Z: No such file or directory\n' \
            uncompress -f file
 
-       # FIXME: The target file must not be created.
-       atf_check cat file
-       atf_check test ! -f nonexistent.Z
+       atf_check test ! -f file
+       atf_check test ! -f file.Z
 }
 
 
@@ -108,6 +110,9 @@
 uncompress_no_source_existing_target_body()
 {
        # PR 19722: uncompressing a missing source truncates target
+       #
+       # Before compress.c 1.28 from 2022-05-22, uncompress truncated the
+       # target.
 
        atf_check sh -c "echo 'hello' > file"
 
@@ -116,8 +121,7 @@
            -e 'inline:uncompress: file.Z: No such file or directory\n' \
            uncompress -f file
 
-       # FIXME: The file must not be truncated.
-       atf_check cat file
+       atf_check -o 'inline:hello\n' cat file
        atf_check test ! -f file.Z
 }
 
diff -r 90c73efb29ea -r 75b591890195 usr.bin/compress/compress.c
--- a/usr.bin/compress/compress.c       Sun May 22 20:49:12 2022 +0000
+++ b/usr.bin/compress/compress.c       Sun May 22 21:16:50 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: compress.c,v 1.27 2022/05/22 19:41:49 rillig Exp $     */
+/*     $NetBSD: compress.c,v 1.28 2022/05/22 21:16:50 rillig Exp $     */
 
 /*-
  * Copyright (c) 1992, 1993
@@ -39,7 +39,7 @@
 #if 0
 static char sccsid[] = "@(#)compress.c 8.2 (Berkeley) 1/7/94";
 #else
-__RCSID("$NetBSD: compress.c,v 1.27 2022/05/22 19:41:49 rillig Exp $");
+__RCSID("$NetBSD: compress.c,v 1.28 2022/05/22 21:16:50 rillig Exp $");
 #endif
 #endif /* not lint */
 
@@ -313,15 +313,15 @@
                oreg = 0;
 
        ifp = ofp = NULL;
-       if ((ofp = fopen(out, "w")) == NULL) {
-               cwarn("%s", out);
-               return;
-       }
 
        if ((ifp = zopen(in, "r", bits)) == NULL) {
                cwarn("%s", in);
                goto err;
        }
+       if ((ofp = fopen(out, "w")) == NULL) {
+               cwarn("%s", out);
+               goto err;
+       }
        if (!isstdin) {
                if (stat(in, &sb)) {
                        cwarn("%s", in);