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author | Paul Eggert <eggert@cs.ucla.edu> | 2017-02-11 23:12:31 -0800 |
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committer | Paul Eggert <eggert@cs.ucla.edu> | 2017-02-11 23:14:02 -0800 |
commit | 376967889ed7ed561e46ff6d88a66779db62737a (patch) | |
tree | 7ca32f07b738fc2f9902c1643bb01dedb7d1066b /src/local.mk | |
parent | 2f69dba5df8caaf9eda658c1808b1379e9949f22 (diff) | |
download | coreutils-376967889ed7ed561e46ff6d88a66779db62737a.tar.xz |
ln: replace destination links more atomically
If the file B already exists, commands like 'ln -f A B' and
'cp -fl A B' no longer remove B before creating the new link.
Instead, they arrange for the new link to replace B atomically.
This should fix a race condition reported by Mike Crowe (Bug#25680).
* NEWS, doc/coreutils.texi (cp invocation, ln invocation):
Document this.
* bootstrap.conf (gnulib_modules): Add symlinkat.
* src/copy.c, src/ln.c: Include force-link.h.
* src/copy.c (same_file_ok): It's also OK to remove a destination
symlink when creating symbolic links, or when the source and
destination are on the same file system and when creating hard links.
* src/copy.c (create_hard_link, copy_internal):
* src/ln.c (do_link):
Rewrite using force_linkat and force_symlinkat, to close a window
where the destination temporarily does not exist.
* src/cp.c (main): Do not set x.unlink_dest_before_opening
merely because we are in link-creation mode.
* src/force-link.c, src/force-link.h: New files.
* src/local.mk (copy_sources, src_ln_SOURCES): Add them.
* tests/cp/same-file.sh: Adjust test case to match fixed behavior.
Diffstat (limited to 'src/local.mk')
-rw-r--r-- | src/local.mk | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/src/local.mk b/src/local.mk index 5b25fcb87..84df09916 100644 --- a/src/local.mk +++ b/src/local.mk @@ -328,7 +328,9 @@ copy_sources = \ src/copy.c \ src/cp-hash.c \ src/extent-scan.c \ - src/extent-scan.h + src/extent-scan.h \ + src/force-link.c \ + src/force-link.h # Use 'ginstall' in the definition of PROGRAMS and in dependencies to avoid # confusion with the 'install' target. The install rule transforms 'ginstall' @@ -357,7 +359,9 @@ src_vdir_SOURCES = src/ls.c src/ls-vdir.c src_id_SOURCES = src/id.c src/group-list.c src_groups_SOURCES = src/groups.c src/group-list.c src_ls_SOURCES = src/ls.c src/ls-ls.c -src_ln_SOURCES = src/ln.c src/relpath.c src/relpath.h +src_ln_SOURCES = src/ln.c \ + src/force-link.c src/force-link.h \ + src/relpath.c src/relpath.h src_chown_SOURCES = src/chown.c src/chown-core.c src_chgrp_SOURCES = src/chgrp.c src/chown-core.c src_kill_SOURCES = src/kill.c src/operand2sig.c |