From b1b0f5c556f5b4080bf16525c309264de73084b7 Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Sun, 10 Jun 2007 14:56:39 +0200 Subject: bug-fix: cp would fail to write through a dangling symlink * NEWS: Mention the bug fix. * src/copy.c (copy_reg): When open fails with EEXIST, the destination is lstat'able, and a symlink, call open again, but now without O_EXCL. * tests/cp/thru-dangling: New file, to test for the above fix. * tests/cp/Makefile.am (TESTS): Add thru-dangling. * THANKS: Add Michael McLagan. Bug report from Michael McLagan in . --- ChangeLog | 11 ++++++++++ NEWS | 3 +++ THANKS | 1 + src/copy.c | 20 +++++++++++++++++-- tests/cp/Makefile.am | 1 + tests/cp/thru-dangling | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 88 insertions(+), 2 deletions(-) create mode 100755 tests/cp/thru-dangling diff --git a/ChangeLog b/ChangeLog index cb3fbfef7..6a30666f1 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,14 @@ +2007-06-10 Jim Meyering + + bug-fix: cp would fail to write through a dangling symlink + * NEWS: Mention the bug fix. + * src/copy.c (copy_reg): When open fails with EEXIST, the destination + is lstat'able, and a symlink, call open again, but now without O_EXCL. + * tests/cp/thru-dangling: New file, to test for the above fix. + * tests/cp/Makefile.am (TESTS): Add thru-dangling. + * THANKS: Add Michael McLagan. + Bug report from Michael McLagan in . + 2007-06-04 Paul Eggert * doc/coreutils.texi (Common options): Mention that -h and diff --git a/NEWS b/NEWS index 715b0d698..9db7902d0 100644 --- a/NEWS +++ b/NEWS @@ -17,6 +17,9 @@ GNU coreutils NEWS -*- outline -*- ** Bug fixes + cp no longer fails to write through a dangling symlink + [bug introduced in coreutils-6.7] + cut now diagnoses a range starting with zero (e.g., -f 0-2) as invalid; before, it would treat it as if it started with 1 (-f 1-2). diff --git a/THANKS b/THANKS index 4ffd1a840..7d9c52752 100644 --- a/THANKS +++ b/THANKS @@ -351,6 +351,7 @@ Michael Hasselberg mikelh@zonta.ping.de Michael Hohn hohn@math.utah.edu Michael J. Croghan mcroghan@usatoday.com Michael McFarland sidlon@yahoo.com +Michael McLagan mmclagan@invlogic.com Michael Piefel piefel@informatik.hu-berlin.de Michael Steffens michael.steffens@s.netic.de Michael Stone mstone@debian.org diff --git a/src/copy.c b/src/copy.c index f4e3b174b..b46221c01 100644 --- a/src/copy.c +++ b/src/copy.c @@ -352,8 +352,24 @@ copy_reg (char const *src_name, char const *dst_name, } if (*new_dst) - dest_desc = open (dst_name, O_WRONLY | O_CREAT | O_EXCL | O_BINARY, - dst_mode & ~omitted_permissions); + { + int open_flags = O_WRONLY | O_CREAT | O_BINARY; + dest_desc = open (dst_name, open_flags | O_EXCL, + dst_mode & ~omitted_permissions); + + /* When trying to copy through a dangling destination symlink, + the above open fails with EEXIST. If that happens, and + lstat'ing the DST_NAME shows that it is a symlink, repeat + the open call, but this time without O_EXCL. */ + if (dest_desc < 0 && errno == EEXIST) + { + struct stat dangling_link_sb; + if (lstat (dst_name, &dangling_link_sb) == 0 + && S_ISLNK (dangling_link_sb.st_mode)) + dest_desc = open (dst_name, open_flags, + dst_mode & ~omitted_permissions); + } + } else omitted_permissions = 0; diff --git a/tests/cp/Makefile.am b/tests/cp/Makefile.am index 536c0221d..52e876b08 100644 --- a/tests/cp/Makefile.am +++ b/tests/cp/Makefile.am @@ -18,6 +18,7 @@ # 02110-1301, USA. TESTS = \ + thru-dangling \ cp-a-selinux \ file-perm-race parent-perm-race \ backup-dir \ diff --git a/tests/cp/thru-dangling b/tests/cp/thru-dangling new file mode 100755 index 000000000..3888cf3d9 --- /dev/null +++ b/tests/cp/thru-dangling @@ -0,0 +1,54 @@ +#!/bin/sh +# Ensure that cp works when the destination is a dangling symlink + +# Copyright (C) 2007 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 2 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, write to the Free Software +# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +# 02110-1301, USA. + +if test "$VERBOSE" = yes; then + set -x + cp --version +fi + +. $srcdir/../envvar-check + +pwd=`pwd` +t0=`echo "$0"|sed 's,.*/,,'`.tmp; tmp=$t0/$$ +trap 'status=$?; cd "$pwd" && chmod -R u+rwx $t0 && rm -rf $t0 && exit $status' 0 +trap '(exit $?); exit $?' 1 2 13 15 + +framework_failure=0 +mkdir -p $tmp || framework_failure=1 +cd $tmp || framework_failure=1 + +ln -s no-such dangle || framework_failure=1 +echo hi > f || framework_failure=1 +echo hi > exp || framework_failure=1 + +if test $framework_failure = 1; then + echo "$0: failure in testing framework" 1>&2 + (exit 1); exit 1 +fi + +fail=0 + +cp f dangle > out 2>&1 || fail=1 +cat no-such >> out || fail=1 + +cmp out exp || fail=1 +test $fail = 1 && diff out exp 2> /dev/null + +(exit $fail); exit $fail -- cgit v1.2.3-54-g00ecf