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[PATCH] ldconfig: Call fsync on temporary files before renaming them [BZ #20890]
- From: fweimer at redhat dot com (Florian Weimer)
- To: libc-alpha at sourceware dot org
- Date: Fri, 12 Jan 2018 12:07:57 +0100
- Subject: [PATCH] ldconfig: Call fsync on temporary files before renaming them [BZ #20890]
- Authentication-results: sourceware.org; auth=none
If the system crashes before the file data has been written to disk, the
file system recovery upon the next mount may restore a partially
rewritten temporary file under the non-temporary (final) name (after the
rename operation).
Some file systems perform an implicit fsync before renaming a file over
another one, but XFS does not, for example.
2018-01-12 Florian Weimer <fweimer@redhat.com>
[BZ #20890]
* elf/cache.c (save_cache): Call fsync on temporary file before
renaming it.
(save_aux_cache): Likewise.
diff --git a/elf/cache.c b/elf/cache.c
index 1ec6ab36e7..2165f8d305 100644
--- a/elf/cache.c
+++ b/elf/cache.c
@@ -449,7 +449,8 @@ save_cache (const char *cache_name)
}
if (write (fd, strings, total_strlen) != (ssize_t) total_strlen
- || close (fd))
+ || fsync (fd) != 0
+ || close (fd) != 0)
error (EXIT_FAILURE, errno, _("Writing of cache data failed"));
/* Make sure user can always read cache file */
@@ -812,7 +813,8 @@ save_aux_cache (const char *aux_cache_name)
if (write (fd, file_entries, file_entries_size + total_strlen)
!= (ssize_t) (file_entries_size + total_strlen)
- || close (fd))
+ || fsync (fd) != 0
+ || close (fd) != 0)
{
unlink (temp_name);
goto out_fail;