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| author | Paul Eggert <eggert@cs.ucla.edu> | 2017-02-11 23:12:31 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2017-02-11 23:14:02 -0800 |
| commit | 376967889ed7ed561e46ff6d88a66779db62737a (patch) | |
| tree | 7ca32f07b738fc2f9902c1643bb01dedb7d1066b /src/force-link.h | |
| 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/force-link.h')
| -rw-r--r-- | src/force-link.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/src/force-link.h b/src/force-link.h new file mode 100644 index 000000000..2a690f680 --- /dev/null +++ b/src/force-link.h @@ -0,0 +1,3 @@ +#include <stdbool.h> +extern int force_linkat (int, char const *, int, char const *, int, bool); +extern int force_symlinkat (char const *, int, char const *, bool); |