mirrors/tar
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/tar.git synced 2026-08-15 13:56:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

Warn “file changed as we read it” less often

Browse Source 
* src/create.c (dump_file0): Remove an fstatat call that is
unnecessary because the file wasn’t read so we can treat the first
fstatat as atomic.  Warn “file changed” when the file’s size,
mtime, user ID, group ID, or mode changes, instead of when the
file’s size or ctime changes.  Also, when such a change happens,
do not change exit status if --ignore-failed-read.  Finally, don’t
attempt to change atime back if it didn’t change.
This commit is contained in:
Paul Eggert
2022-06-09 15:50:42 -07:00
parent bc7e758b27
commit c1027eb5ae
3 changed files with 61 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/create.c
+38 -16
View File
@@ -1639,8 +1639,6 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
{
union block *header;
char type;
off_t original_size;
struct timespec original_ctime;
off_t block_ordinal = -1;
int fd = 0;
bool is_dir;
@@ -1683,10 +1681,11 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
return;
}
st->archive_file_size = original_size = st->stat.st_size;
struct stat st1 = st->stat;
st->archive_file_size = st->stat.st_size;
st->atime = get_stat_atime (&st->stat);
st->mtime = get_stat_mtime (&st->stat);
st->ctime = original_ctime = get_stat_ctime (&st->stat);
st->ctime = get_stat_ctime (&st->stat);
#ifdef S_ISHIDDEN
if (S_ISHIDDEN (st->stat.st_mode))
@@ -1736,7 +1735,7 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
if (is_dir || S_ISREG (st->stat.st_mode) || S_ISCTG (st->stat.st_mode))
{
bool ok;
struct stat final_stat;
struct stat st2;
xattrs_acls_get (parentfd, name, st, 0, !is_dir);
xattrs_selinux_get (parentfd, name, st, fd);
@@ -1804,31 +1803,54 @@ dump_file0 (struct tar_stat_info *st, char const *name, char const *p)
errno = - parentfd;
ok = false;
}
else
ok = fstatat (parentfd, name, &final_stat, fstatat_flags) == 0;
}
else
ok = fstat (fd, &final_stat) == 0;
ok = fstat (fd, &st2) == 0;
if (! ok)
file_removed_diag (p, top_level, stat_diag);
}
if (ok)
if (ok && fd)
{
if ((timespec_cmp (get_stat_ctime (&final_stat), original_ctime) != 0
/* Original ctime will change if the file is a directory and
--remove-files is given */
&& !(remove_files_option && is_dir))
|| original_size < final_stat.st_size)
/* Heuristically check whether the file is the same in all
attributes that tar cares about and can easily check.
Although the check is not perfect since it does not
consult file contents, it is typically good enough.
Do not check atime which is saved only to replace it later.
Do not check ctime where changes might be benign (e.g.,
another process creates a hard link to the file). */
/* If the file's user ID, group ID or mode changed, tar may
have output the wrong info for the file. */
ok &= st1.st_uid == st2.st_uid;
ok &= st1.st_gid == st2.st_gid;
ok &= st1.st_mode == st2.st_mode;
/* Likewise for the file's mtime, but skip this check if it
is a directory possibly updated by --remove-files. */
if (! (is_dir && remove_files_option))
ok &= ! timespec_cmp (get_stat_mtime (&st1),
get_stat_mtime (&st2));
/* Likewise for the file's size, but skip this check if it
is a directory as tar does not output directory sizes.
Although dump_regular_file caught regular file shrinkage,
it shouldn't hurt to check for shrinkage again now;
plus, the file may have grown. */
if (!is_dir)
ok &= st1.st_size == st2.st_size;
if (!ok)
{
WARNOPT (WARN_FILE_CHANGED,
(0, 0, _("%s: file changed as we read it"),
quotearg_colon (p)));
set_exit_status (TAREXIT_DIFFERS);
if (! ignore_failed_read_option)
set_exit_status (TAREXIT_DIFFERS);
}
else if (atime_preserve_option == replace_atime_preserve
&& fd && (is_dir || original_size != 0)
&& timespec_cmp (st->atime, get_stat_atime (&st2)) != 0
&& set_file_atime (fd, parentfd, name, st->atime) != 0)
utime_error (p);
}