Jim Meyering <jim <at> meyering.net> writes: > Regardless of POSIX, what if an application requires that output and > attempts to parse it? In that case, a successful exit status is defintely > at odds with empty stderr (which could arise also due to ENOSPC). > > So I'd say it's a bug.
Here's a patch, including a testsuite addition (along with a cleanup to allow clean compilation on cygwin). OK to apply? >From 8cea0f3d5628ea3e4f74db0a66486cae5d92122a Mon Sep 17 00:00:00 2001 From: Eric Blake <[email protected]> Date: Fri, 28 Aug 2009 08:40:06 -0600 Subject: [PATCH 1/2] dd: detect closed stderr * src/dd.c (maybe_close_stdout): Always flush stderr. * tests/dd/stderr: New test, borrowing from misc/close-stdout. * tests/Makefile.am (TESTS): Run it. * NEWS: Mention this. --- NEWS | 3 +++ src/dd.c | 3 +++ tests/Makefile.am | 1 + tests/dd/stderr | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 54 insertions(+), 0 deletions(-) create mode 100755 tests/dd/stderr diff --git a/NEWS b/NEWS index c125b31..581620f 100644 --- a/NEWS +++ b/NEWS @@ -8,6 +8,9 @@ GNU coreutils NEWS -*- outline -*- due to their running on a kernel older than what was implied by headers and libraries tested at configure time. + dd now returns non-zero status if it encountered a write error while + printing a summary to stderr. + * Noteworthy changes in release 7.5 (2009-08-20) [stable] diff --git a/src/dd.c b/src/dd.c index dc15cfd..c016d3d 100644 --- a/src/dd.c +++ b/src/dd.c @@ -25,6 +25,7 @@ #include <getopt.h> #include "system.h" +#include "close-stream.h" #include "error.h" #include "fd-reopen.h" #include "gethrxtime.h" @@ -450,6 +451,8 @@ maybe_close_stdout (void) { if (close_stdout_required) close_stdout (); + else if (close_stream (stderr) != 0) + _exit (exit_failure); } void diff --git a/tests/Makefile.am b/tests/Makefile.am index 6ad6133..c88dd9c 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -305,6 +305,7 @@ TESTS = \ dd/skip-seek \ dd/skip-seek2 \ dd/skip-seek-past-file \ + dd/stderr \ dd/unblock-sync \ df/total-verify \ du/2g \ diff --git a/tests/dd/stderr b/tests/dd/stderr new file mode 100755 index 0000000..46ffe48 --- /dev/null +++ b/tests/dd/stderr @@ -0,0 +1,47 @@ +#!/bin/sh +# Ensure dd recognizes failure to write to stderr. + +# Copyright (C) 2009 Free Software Foundation, Inc. + +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +if test "$VERBOSE" = yes; then + set -x + dd --version +fi + +. $srcdir/test-lib.sh + +p="$abs_top_builddir" + +fail=0 + +# Ensure this exits successfully, even though stderr is closed, +# because it generates no stderr output. +dd --help >/dev/null 2>&- || fail=1 + +# If 2>&- works, ensure this fails, because stderr is closed and it +# *does* generate output. 2>&- apparently does not work in HP-UX 11.23. +# This test is ineffective unless /dev/stderr also works. +if "$p/src/test" -w /dev/stderr 2>/dev/null && + "$p/src/test" ! -w /dev/stderr 2>&-; then + echo | dd 2>&- && fail=1 +fi + +# Likewise for /dev/full, if /dev/full works. +if test -w /dev/full && test -c /dev/full; then + echo | dd 2>/dev/full && fail=1 +fi + +Exit $fail -- 1.6.3.2 >From be4960b62893292b0b06abb129fca9c4c9e7f496 Mon Sep 17 00:00:00 2001 From: Eric Blake <[email protected]> Date: Tue, 25 Aug 2009 23:40:40 -0600 Subject: [PATCH 2/2] build: avoid unused variable warnings on cygwin * src/copy.c (clone_file, copy_attr_by_fd, copy_attr_by_name): Add ATTRIBUTE_UNUSED. * src/remove.c (dirent_inode_sort_may_be_useful): Likewise. --- src/copy.c | 14 +++++++++----- src/remove.c | 5 ++++- 2 files changed, 13 insertions(+), 6 deletions(-) diff --git a/src/copy.c b/src/copy.c index 238764a..8176994 100644 --- a/src/copy.c +++ b/src/copy.c @@ -140,7 +140,7 @@ utimens_symlink (char const *file, struct timespec const *timespec) /* Perform the O(1) btrfs clone operation, if possible. Upon success, return 0. Otherwise, return -1 and set errno. */ static inline int -clone_file (int dest_fd, int src_fd) +clone_file (int dest_fd ATTRIBUTE_UNUSED, int src_fd ATTRIBUTE_UNUSED) { #ifdef __linux__ # undef BTRFS_IOCTL_MAGIC @@ -251,15 +251,19 @@ copy_attr_by_name (char const *src_path, char const *dst_path, #else /* USE_XATTR */ static bool -copy_attr_by_fd (char const *src_path, int src_fd, - char const *dst_path, int dst_fd, const struct cp_options *x) +copy_attr_by_fd (char const *src_path ATTRIBUTE_UNUSED, + int src_fd ATTRIBUTE_UNUSED, + char const *dst_path ATTRIBUTE_UNUSED, + int dst_fd ATTRIBUTE_UNUSED, + const struct cp_options *x ATTRIBUTE_UNUSED) { return true; } static bool -copy_attr_by_name (char const *src_path, char const *dst_path, - const struct cp_options *x) +copy_attr_by_name (char const *src_path ATTRIBUTE_UNUSED, + char const *dst_path ATTRIBUTE_UNUSED, + const struct cp_options *x ATTRIBUTE_UNUSED) { return true; } diff --git a/src/remove.c b/src/remove.c index 6c8613b..2c4a178 100644 --- a/src/remove.c +++ b/src/remove.c @@ -1311,7 +1311,10 @@ dirent_inode_sort_may_be_useful (int dir_fd) } } # else /* !HAVE_STRUCT_STATFS_F_TYPE */ -static bool dirent_inode_sort_may_be_useful (int dir_fd) { return true; } +static bool dirent_inode_sort_may_be_useful (int dir_fd ATTRIBUTE_UNUSED) +{ + return true; +} # endif /* !HAVE_STRUCT_STATFS_F_TYPE */ #endif /* HAVE_STRUCT_DIRENT_D_TYPE */ -- 1.6.3.2
