This avoids a harmless (but distracting) case of memory being
used-uninitialized.
+2007-02-21 Paul Eggert <eggert@cs.ucla.edu>
+
+ Honor dd's noatime flag if possible, even if not supported on build fs
+ * doc/coreutils.texi (dd invocation): Warn that noatime might not be
+ reliable.
+ * src/dd.c (flags, usage): Look at O_NOATIME, not
+ HAVE_WORKING_O_NOATIME, to decide whether to support the noatime
+ flag, so that dd attempts O_NOATIME even if the build file system
+ does not support it. Problem reported by Jim Meyering today in
+ bug-coreutils.
+ * tests/dd/misc: Generate a warning, not a failure, if noatime
+ exists but fails.
+
2007-02-21 Jim Meyering <jim@meyering.net>
* tests/misc/date: Remove vestigial use of Data::Dumper.
@opindex noatime
@cindex access time
Do not update the file's access time.
+Some older file systems silently ignore this flag, so it is a good
+idea to test it on your files before relying on it.
@item noctty
@opindex noctty
{"direct", O_DIRECT},
{"directory", O_DIRECTORY},
{"dsync", O_DSYNC},
- {"noatime", HAVE_WORKING_O_NOATIME ? O_NOATIME : 0},
+ {"noatime", O_NOATIME},
{"noctty", O_NOCTTY},
{"nofollow", HAVE_WORKING_O_NOFOLLOW ? O_NOFOLLOW : 0},
{"nolinks", O_NOLINKS},
fputs (_(" sync likewise, but also for metadata\n"), stdout);
if (O_NONBLOCK)
fputs (_(" nonblock use non-blocking I/O\n"), stdout);
- if (HAVE_WORKING_O_NOATIME)
+ if (O_NOATIME)
fputs (_(" noatime do not update access time\n"), stdout);
if (O_NOCTTY)
fputs (_(" noctty do not assign controlling terminal from file\n"),
dd --version
fi
+fail=0
+warn=0
test_failure=0
echo data > $tmp_in || test_failure=1
ln $tmp_in $tmp_in2 || test_failure=1
if dd iflag=noatime if=$tmp_in of=$tmp_out 2> /dev/null; then
new_ls=`ls -u --full-time $tmp_in`
if test "x$old_ls" != "x$new_ls"; then
- echo "dd iflag=noatime updated atime; O_NOATIME bug in your kernel?" >&2
- fail=1
+ cat >&2 <<EOF
+=================================================================
+$0: WARNING!!!
+This operating system has the O_NOATIME file status flag,
+but it is silently ignored in some cases.
+Therefore, dd options like iflag=noatime may be silently ignored.
+=================================================================
+EOF
+ warn=77
fi
fi
outbytes=`echo x | dd bs=3 ibs=10 obs=10 conv=sync 2>/dev/null | wc -c`
test "$outbytes" -eq 3 || fail=1
-rm -f $tmp_in $tmp_in2 $tmp_sym $tmp_out
+rm -f $tmp_in $tmp_in2 $tmp_sym $tmp_out || fail=1
+test $fail -eq 0 && fail=$warn
exit $fail