From eae535e1a322e244248bd31ed7e21ac95ecaa16d Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Mon, 27 Jul 2009 17:08:02 +0200 Subject: [PATCH] cp -pP (and e.g., -a): preserve time stamps on symlinks, too * src/copy.c (utimensat_if_possible): New function. (copy_internal): Remove variable, "preserve_metadata". Replace with "dest_is_symlink". That covers all cases but one: the one in which cp --link has created hard links to non-directories. In that case, there is no need to update attributes of the links. Use utimensat_if_possible, to preserve timestamps of symlinks. * NEWS (New features): Mention this. * tests/Makefile.am (TESTS): Add cp/preserve-slink-time. * tests/cp/preserve-slink-time: New file. * m4/jm-macros.m4 (coreutils_MACROS): Test for utimensat. Reported in http://bugzilla.redhat.com/230866 --- NEWS | 2 ++ m4/jm-macros.m4 | 3 +++ src/copy.c | 42 ++++++++++++++++++++++++++---------------- tests/Makefile.am | 1 + tests/cp/preserve-slink-time | 44 ++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 76 insertions(+), 16 deletions(-) create mode 100755 tests/cp/preserve-slink-time diff --git a/NEWS b/NEWS index 5058b5783..0a0d4a719 100644 --- a/NEWS +++ b/NEWS @@ -38,6 +38,8 @@ GNU coreutils NEWS -*- outline -*- chroot now accepts the options --userspec and --groups. + cp now preserves time stamps on symbolic links, when possible + cp, install, mv: take advantage of btrfs' O(1) copy-on-write feature when both the source and destination are on the same btrfs partition. diff --git a/m4/jm-macros.m4 b/m4/jm-macros.m4 index f862984cc..32a0954a7 100644 --- a/m4/jm-macros.m4 +++ b/m4/jm-macros.m4 @@ -89,6 +89,9 @@ AC_DEFUN([coreutils_MACROS], tcgetpgrp \ ) + # for cp.c + AC_CHECK_FUNCS_ONCE([utimensat]) + dnl This can't use AC_REQUIRE; I'm not quite sure why. cu_PREREQ_STAT_PROG diff --git a/src/copy.c b/src/copy.c index bbed336b1..24b5f6b46 100644 --- a/src/copy.c +++ b/src/copy.c @@ -118,6 +118,20 @@ static bool owner_failure_ok (struct cp_options const *x); static char const *top_level_src_name; static char const *top_level_dst_name; +/* Wrap utimensat-with-AT_FDCWD and utimens, to keep these + cpp directives out of the main code. */ +static inline int +utimensat_if_possible (char const *file, struct timespec const *timespec) +{ + return +#if HAVE_UTIMENSAT + utimensat (AT_FDCWD, file, timespec, AT_SYMLINK_NOFOLLOW) +#else + utimens (file, timespec) +#endif + ; +} + /* Perform the O(1) btrfs clone operation, if possible. Upon success, return 0. Otherwise, return -1 and set errno. */ static inline int @@ -1211,7 +1225,7 @@ copy_internal (char const *src_name, char const *dst_name, bool backup_succeeded = false; bool delayed_ok; bool copied_as_regular = false; - bool preserve_metadata; + bool dest_is_symlink = false; bool have_dst_lstat = false; if (x->move_mode && rename_succeeded) @@ -1810,12 +1824,6 @@ copy_internal (char const *src_name, char const *dst_name, } } - /* In certain modes (cp's --symbolic-link), and for certain file types - (symlinks and hard links) it doesn't make sense to preserve metadata, - or it's possible to preserve only some of it. - In such cases, set this variable to zero. */ - preserve_metadata = true; - if (S_ISDIR (src_mode)) { struct dir_list *dir; @@ -1909,8 +1917,7 @@ copy_internal (char const *src_name, char const *dst_name, } else if (x->symbolic_link) { - preserve_metadata = false; - + dest_is_symlink = true; if (*src_name != '/') { /* Check that DST_NAME denotes a file in the current directory. */ @@ -1962,7 +1969,6 @@ copy_internal (char const *src_name, char const *dst_name, #endif ) { - preserve_metadata = false; if (link (src_name, dst_name)) { error (0, errno, _("cannot create link %s"), quote (dst_name)); @@ -2007,6 +2013,7 @@ copy_internal (char const *src_name, char const *dst_name, else if (S_ISLNK (src_mode)) { char *src_link_val = areadlink_with_size (src_name, src_sb.st_size); + dest_is_symlink = true; if (src_link_val == NULL) { error (0, errno, _("cannot read symbolic link %s"), quote (src_name)); @@ -2045,9 +2052,6 @@ copy_internal (char const *src_name, char const *dst_name, if (x->preserve_security_context) restore_default_fscreatecon_or_die (); - /* There's no need to preserve timestamps or permissions. */ - preserve_metadata = false; - if (x->preserve_ownership) { /* Preserve the owner and group of the just-`copied' @@ -2084,8 +2088,10 @@ copy_internal (char const *src_name, char const *dst_name, record_file (x->dest_info, dst_name, &sb); } - if ( ! preserve_metadata) - return true; + /* If we've just created a hard-link due to cp's --link option, + we're done. */ + if (x->hard_link && ! S_ISDIR (src_mode)) + return delayed_ok; if (copied_as_regular) return delayed_ok; @@ -2108,7 +2114,7 @@ copy_internal (char const *src_name, char const *dst_name, timespec[0] = get_stat_atime (&src_sb); timespec[1] = get_stat_mtime (&src_sb); - if (utimens (dst_name, timespec) != 0) + if (utimensat_if_possible (dst_name, timespec) != 0) { error (0, errno, _("preserving times for %s"), quote (dst_name)); if (x->require_preserve) @@ -2116,6 +2122,10 @@ copy_internal (char const *src_name, char const *dst_name, } } + /* The operations beyond this point may dereference a symlink. */ + if (dest_is_symlink) + return delayed_ok; + /* Avoid calling chown if we know it's not necessary. */ if (x->preserve_ownership && (new_dst || !SAME_OWNER_AND_GROUP (src_sb, dst_sb))) diff --git a/tests/Makefile.am b/tests/Makefile.am index 59737a05d..ad19d0264 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -287,6 +287,7 @@ TESTS = \ cp/parent-perm-race \ cp/perm \ cp/preserve-2 \ + cp/preserve-slink-time \ cp/proc-short-read \ cp/proc-zero-len \ cp/r-vs-symlink \ diff --git a/tests/cp/preserve-slink-time b/tests/cp/preserve-slink-time new file mode 100755 index 000000000..c5c21a5e1 --- /dev/null +++ b/tests/cp/preserve-slink-time @@ -0,0 +1,44 @@ +#!/bin/sh +# Verify that cp -Pp preserves times even on symlinks. + +# 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 . + +if test "$VERBOSE" = yes; then + set -x + cp --version +fi + +. $srcdir/test-lib.sh + +grep '^#define HAVE_UTIMENSAT' "$CONFIG_HEADER" > /dev/null || + skip_test_ 'this system lacks the utimensat function' + +ln -s no-such dangle || framework_failure + +# If the current file system lacks sub-second resolution, sleep for 2s to +# ensure that the times on the copy are different from those of the original. +case $(stat --format=%y dangle) in + ??:??:??.000000000) sleep 2;; +esac + +cp -Pp dangle d2 || framework_failure +stat --format=%y dangle > t1 || framework_failure +stat --format=%y d2 > t2 || framework_failure + +fail=0 +compare t1 t2 || fail=1 + +Exit $fail -- 2.11.4.GIT