On Sun, Aug 24, 2003 at 12:16:47AM +0100, Michael Brown
wrote:> We've just been hit rather badly by a very nasty bug that can cause
rsync
> to silently discard files or fill them with zeroes. It happens when e.g.
> opendir() succeeds but readdir() returns an error; rsync does not check
> for an error from readdir() and so simply ignores the error (along with
> any remaining files in the directory). No error is reported to the user,
> who will then happily assume that their backup of 50GB worth of
> data succeeded...
>
> This issue is discussed wrt the GNU fileutils at
> http://www.mail-archive.com/bug-fileutils@gnu.org/msg01847.html
> GNU fileutils *do* report errors under these circumstances. Although it
> is arguably a kernel bug, I think rsync should err on the side of paranoia
> in the same way as the GNU utilities.
>
> A similar error can occur when open() succeeds but subsequent calls to
> read() fail: under these circumstances rsync will transfer zeroes instead
> of the actual file data and will again report no errors to the user.
>
> The attached patch fixes both of these problems.
There is a patch on-list for the read error. Your fix is
incorrect because it causes rsync to exit if a file is
truncated during read.
I'll look closer at the readir error when i get a chance.
>
> I am not a list member; please Cc me on all replies.
>
> Michael
> Index: fileio.c
> ==================================================================> RCS
file: /cvsroot/rsync/fileio.c,v
> retrieving revision 1.6
> diff -u -r1.6 fileio.c
> --- fileio.c 22 May 2003 23:24:44 -0000 1.6
> +++ fileio.c 23 Aug 2003 23:03:01 -0000
> @@ -191,7 +191,10 @@
> }
>
> if ((nread=read(map->fd,map->p + read_offset,read_size)) !=
read_size) {
> - if (nread < 0) nread = 0;
> + if (nread < 0) {
> + rprintf(FERROR,"read failed in map_ptr\n");
> + exit_cleanup(RERR_FILEIO);
> + }
> /* the best we can do is zero the buffer - the file
> has changed mid transfer! */
> memset(map->p+read_offset+nread, 0, read_size - nread);
> Index: flist.c
> ==================================================================> RCS
file: /cvsroot/rsync/flist.c,v
> retrieving revision 1.139
> diff -u -r1.139 flist.c
> --- flist.c 17 Aug 2003 21:29:11 -0000 1.139
> +++ flist.c 23 Aug 2003 23:03:02 -0000
> @@ -877,13 +877,18 @@
> }
> }
>
> - for (di = readdir(d); di; di = readdir(d)) {
> + for (errno = 0, di = readdir(d); di; errno = 0, di = readdir(d)) {
> char *dname = d_name(di);
> if (dname[0] == '.' && (dname[1] == '\0' ||
> (dname[1] == '.' && dname[2] == '\0')))
> continue;
> strlcpy(p, dname, MAXPATHLEN - l);
> send_file_name(f, flist, fname, recurse, 0);
> + }
> + if ( errno ) {
> + io_error = 1;
> + rprintf(FERROR, "readdir(%s): %s\n", dir, strerror(errno));
> + /* Don't return yet; we want to clean up first */
> }
>
> if (local_exclude_list)
> Index: rsync.c
> ==================================================================> RCS
file: /cvsroot/rsync/rsync.c,v
> retrieving revision 1.120
> diff -u -r1.120 rsync.c
> --- rsync.c 18 Feb 2003 18:07:36 -0000 1.120
> +++ rsync.c 23 Aug 2003 23:03:02 -0000
> @@ -86,7 +86,7 @@
> return -1;
> }
>
> - for (di=readdir(d); di; di=readdir(d)) {
> + for (errno = 0, di=readdir(d); di; errno = 0, di=readdir(d)) {
> char *dname = d_name(di);
> if (strcmp(dname,".")==0 ||
> strcmp(dname,"..")==0)
> @@ -99,6 +99,12 @@
> return -1;
> }
> }
> + if ( errno ) {
> + closedir(d);
> + rprintf(FERROR,"delete_file: readdir(%s): %s\n",
> + fname,strerror(errno));
> + return -1;
> + }
>
> closedir(d);
>
> --
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--
________________________________________________________________
J.W. Schultz Pegasystems Technologies
email address: jw@pegasys.ws
Remember Cernan and Schmitt