-*- indented-text -*- BUGS --------------------------------------------------------------- There seems to be a bug with hardlinks mbp/2 build$ ls -l /tmp/a /tmp/b -i /tmp/a: total 32 2568307 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a1 2568307 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a2 2568307 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a3 2568310 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a4 2568310 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a5 2568310 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b1 2568310 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b2 2568310 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b3 /tmp/b: total 32 2568309 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a1 2568309 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a2 2568309 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a3 2568311 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a4 2568311 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a5 2568311 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b1 2568311 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b2 2568311 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b3 mbp/2 build$ rm -r /tmp/b && ./rsync -avH /tmp/a/ /tmp/b building file list ... done created directory /tmp/b ./ a1 a4 a2 => a1 a3 => a2 wrote 350 bytes read 52 bytes 804.00 bytes/sec total size is 232 speedup is 0.58 mbp/2 build$ rm -r /tmp/b mbp/2 build$ ls -l /tmp/b ls: /tmp/b: No such file or directory mbp/2 build$ rm -r /tmp/b && ./rsync -avH /tmp/a/ /tmp/b rm: cannot remove `/tmp/b': No such file or directory mbp/2 build$ rm -f -r /tmp/b && ./rsync -avH /tmp/a/ /tmp/b building file list ... done created directory /tmp/b ./ a1 a4 a2 => a1 a3 => a2 wrote 350 bytes read 52 bytes 804.00 bytes/sec total size is 232 speedup is 0.58 mbp/2 build$ ls -l /tmp/b total 32 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a1 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a2 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a3 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a4 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a5 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b1 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b2 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b3 mbp/2 build$ ls -l /tmp/a total 32 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a1 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a2 -rw-rw-r-- 3 mbp mbp 29 Mar 25 17:30 a3 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a4 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 a5 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b1 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b2 -rw-rw-r-- 5 mbp mbp 29 Mar 25 17:30 b3 Progress indicator can produce corrupt output when transferring directories: main/binary-arm/ main/binary-arm/admin/ main/binary-arm/base/ main/binary-arm/comm/8.56kB/s 0:00:52 main/binary-arm/devel/ main/binary-arm/doc/ main/binary-arm/editors/ main/binary-arm/electronics/s 0:00:53 main/binary-arm/games/ main/binary-arm/graphics/ main/binary-arm/hamradio/ main/binary-arm/interpreters/ main/binary-arm/libs/6.61kB/s 0:00:54 main/binary-arm/mail/ main/binary-arm/math/ main/binary-arm/misc/ lchmod I don't think we handle this properly on systems that don't have the call. DAEMON -------------------------------------------------------------- server-imposed bandwidth limits rsyncd over ssh There are already some patches to do this. BitKeeper uses a server whose login shell is set to bkd. That's probably a reasonable approach. FEATURES ------------------------------------------------------------ --dry-run is insufficiently dry Mark Santcroos points out that -n fails to list files which have only metadata changes, though it probably should. There may be a Debian bug about this as well. use chroot If the platform doesn't support it, then don't even try. If running as non-root, then don't fail, just give a warning. (There was a thread about this a while ago?) http://lists.samba.org/pipermail/rsync/2001-August/thread.html http://lists.samba.org/pipermail/rsync/2001-September/thread.html --files-from Avoids traversal. Better option than a pile of --include statements for people who want to generate the file list using a find(1) command or a script. File list structure in memory Rather than one big array, perhaps have a tree in memory mirroring the directory tree. This might make sorting much faster! (I'm not sure it's a big CPU problem, mind you.) It might also reduce memory use in storing repeated directory names -- again I'm not sure this is a problem. Performance Traverse just one directory at a time. Tridge says it's possible. At the moment rsync reads the whole file list into memory at the start, which makes us use a lot of memory and also not pipeline network access as much as we could. Handling duplicate names We need to be careful of duplicate names getting into the file list. See clean_flist(). This could happen if multiple arguments include the same file. Bad. I think duplicates are only a problem if they're both flowing through the pipeline at the same time. For example we might have updated the first occurrence after reading the checksums for the second. So possibly we just need to make sure that we don't have both in the pipeline at the same time. Possibly if we did one directory at a time that would be sufficient. Alternatively we could pre-process the arguments to make sure no duplicates will ever be inserted. There could be some bad cases when we're collapsing symlinks. We could have a hash table. The root of the problem is that we do not want more than one file list entry referring to the same file. At first glance there are several ways this could happen: symlinks, hardlinks, and repeated names on the command line. If names are repeated on the command line, they may be present in different forms, perhaps by traversing directory paths in different ways, traversing paths including symlinks. Also we need to allow for expansion of globs by rsync. At the moment, clean_flist() requires having the entire file list in memory. Duplicate names are detected just by a string comparison. We don't need to worry about hard links causing duplicates because files are never updated in place. Similarly for symlinks. I think even if we're using a different symlink mode we don't need to worry. Unless we're really clever this will introduce a protocol incompatibility, so we need to be able to accept the old format as well. Memory accounting At exit, show how much memory was used for the file list, etc. Also we do a wierd exponential-growth allocation in flist.c. I'm not sure this makes sense with modern mallocs. At any rate it will make us allocate a huge amount of memory for large file lists. Hard-link handling At the moment hardlink handling is very expensive, so it's off by default. It does not need to be so. Since most of the solutions are rather intertwined with the file list it is probably better to fix that first, although fixing hardlinks is possibly simpler. We can rule out hardlinked directories since they will probably screw us up in all kinds of ways. They simply should not be used. At the moment rsync only cares about hardlinks to regular files. I guess you could also use them for sockets, devices and other beasts, but I have not seen them. When trying to reproduce hard links, we only need to worry about files that have more than one name (nlinks>1 && !S_ISDIR). The basic point of this is to discover alternate names that refer to the same file. All operations, including creating the file and writing modifications to it need only to be done for the first name. For all later names, we just create the link and then leave it alone. If hard links are to be preserved: Before the generator/receiver fork, the list of files is received from the sender (recv_file_list), and a table for detecting hard links is built. The generator looks for hard links within the file list and does not send checksums for them, though it does send other metadata. The sender sends the device number and inode with file entries, so that files are uniquely identified. The receiver goes through and creates hard links (do_hard_links) after all data has been written, but before directory permissions are set. At the moment device and inum are sent as 4-byte integers, which will probably cause problems on large filesystems. On Linux the kernel uses 64-bit ino_t's internally, and people will soon have filesystems big enough to use them. We ought to follow NFS4 in using 64-bit device and inode identification, perhaps with a protocol version bump. Once we've seen all the names for a particular file, we no longer need to think about it and we can deallocate the memory. We can also have the case where there are links to a file that are not in the tree being transferred. There's nothing we can do about that. Because we rename the destination into place after writing, any hardlinks to the old file are always going to be orphaned. In fact that is almost necessary because otherwise we'd get really confused if we were generating checksums for one name of a file and modifying another. At the moment the code seems to make a whole second copy of the file list, which seems unnecessary. We should have a test case that exercises hard links. Since it might be hard to compare ./tls output where the inodes change we might need a little program to check whether several names refer to the same file. IPv6 Implement suggestions from http://www.kame.net/newsletter/19980604/ and ftp://ftp.iij.ad.jp/pub/RFC/rfc2553.txt If a host has multiple addresses, then listen try to connect to all in order until we get through. (getaddrinfo may return multiple addresses.) This is kind of implemented already. Possibly also when starting as a server we may need to listen on multiple passive addresses. This might be a bit harder, because we may need to select on all of them. Hm. Define a syntax for IPv6 literal addresses. Since they include colons, they tend to break most naming systems, including ours. Based on the HTTP IPv6 syntax, I think we should use rsync://[::1]/foo/bar [::1]::bar which should just take a small change to the parser code. Errors If we hang or get SIGINT, then explain where we were up to. Perhaps have a static buffer that contains the current function name, or some kind of description of what we were trying to do. This is a little easier on people than needing to run strace/truss. "The dungeon collapses! You are killed." Rather than "unexpected eof" give a message that is more detailed if possible and also more helpful. If we get an error writing to a socket, then we should perhaps continue trying to read to see if an error message comes across explaining why the socket is closed. I'm not sure if this would work, but it would certainly make our messages more helpful. What happens if a directory is missing -x attributes. Do we lose our load? (Debian #28416) Probably fixed now, but a test case would be good. File attributes Device major/minor numbers should be at least 32 bits each. See http://lists.samba.org/pipermail/rsync/2001-November/005357.html Transfer ACLs. Need to think of a standard representation. Probably better not to even try to convert between NT and POSIX. Possibly can share some code with Samba. Empty directories With the current common --include '*/' --exclude '*' pattern, people can end up with many empty directories. We might avoid this by lazily creating such directories. zlib Perhaps don't use our own zlib. Advantages: - will automatically be up to date with bugfixes in zlib - can leave it out for small rsync on e.g. recovery disks - can use a shared library - avoids people breaking rsync by trying to do this themselves and messing up Should we ship zlib for systems that don't have it, or require people to install it separately? Apparently this will make us incompatible with versions of rsync that use the patched version of rsync. Probably the simplest way to do this is to just disable gzip (with a warning) when talking to old versions. proxy authentication Allow RSYNC_PROXY to be http://user:pass@proxy.foo:3128/, and do HTTP Basic Proxy-Authentication. Multiple schemes are possible, up to and including the insanity that is NTLM, but Basic probably covers most cases. SOCKS Add --with-socks, and then perhaps a command-line option to put them on or off. This might be more reliable than LD_PRELOAD hacks. Better statistics: mbp: hey, how about an rsync option that just gives you the summary without the list of files? And perhaps gives more information like the number of new files, number of changed, deleted, etc. ? Rasmus: nice idea there is --stats but at the moment it's very tridge-oriented rather than user-friendly it would be nice to improve it that would also work well with --dryrun TDB: Rather than storing the file list in memory, store it in a TDB. This *might* make memory usage lower while building the file list. Hashtable lookup will mean files are not transmitted in order, though... hm. This would neatly eliminate one of the major post-fork shared data structures. chmod: On 12 Mar 2002, Dave Dykstra wrote: > If we would add an option to do that functionality, I would vote for one > that was more general which could mask off any set of permission bits and > possibly add any set of bits. Perhaps a chmod-like syntax if it could be > implemented simply. I think that would be good too. For example, people uploading files to a web server might like to say rsync -avzP --chmod a+rX ./ sourcefrog.net:/home/www/sourcefrog/ Ideally the patch would implement as many of the gnu chmod semantics as possible. I think the mode parser should be a separate function that passes back something like (mask,set) description to the rest of the program. For bonus points there would be a test case for the parser. (Debian #23628) --diff Allow people to specify the diff command. (Might want to use wdiff, gnudiff, etc.) Just diff the temporary file with the destination file, and delete the tmp file rather than moving it into place. Interaction with --partial. Security interactions with daemon mode? (Suggestion from david.e.sewell) Incorrect timestamps (Debian #100295) A bit hard to believe, but apparently it happens. Check "refuse options works" We need a test case for this... Was this broken when we changed to popt? String area code Test whether this is actually faster than just using malloc(). If it's not (anymore), throw it out. PLATFORMS ------------------------------------------------------------ Win32 Don't detach, because this messes up --srvany. http://sources.redhat.com/ml/cygwin/2001-08/msg00234.html According to "Effective TCP/IP Programming" (??) close() on a socket has incorrect behaviour on Windows -- it sends a RST packet to the other side, which gives a "connection reset by peer" error. On that platform we should probably do shutdown() instead. However, on Unix we are correct to call close(), because shutdown() discards untransmitted data. DEVELOPMENT ---------------------------------------------------------- Splint Build rsync with SPLINT to try to find security holes. Add annotations as necessary. Keep track of the number of warnings found initially, and see how many of them are real bugs, or real security bugs. Knowing the percentage of likely hits would be really interesting for other projects. Torture test Something that just keeps running rsync continuously over a data set likely to generate problems. Cross-testing Run current rsync versions against significant past releases. Memory debugger jra recommends Valgrind: http://devel-home.kde.org/~sewardj/ TESTING -------------------------------------------------------------- Cross-test versions Part of the regression suite should be making sure that we don't break backwards compatibility: old clients vs new servers and so on. Ideally we would test the cross product of versions. It might be sufficient to test downloads from well-known public rsync servers running different versions of rsync. This will give some testing and also be the most common case for having different versions and not being able to upgrade. Test large files Sparse and non-sparse Mutator program Insert bytes, delete bytes, swap blocks, ... configure option to enable dangerous tests If tests are skipped, say why. Test daemon feature to disallow particular options. Pipe program that makes slow/jerky connections. Versions of read() and write() that corrupt the stream, or abruptly fail Separate makefile target to run rough tests -- or perhaps just run them every time? DOCUMENTATION -------------------------------------------------------- Update README Keep list of open issues and todos on the web site Update web site from CVS BUILD FARM ----------------------------------------------------------- Add machines AMDAHL UTS (Dave Dykstra) Cygwin (on different versions of Win32?) HP-UX variants (via HP?) SCO LOGGING -------------------------------------------------------------- Perhaps flush stdout after each filename, so that people trying to monitor progress in a log file can do so more easily. See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=48108 At the connections that just get a list of modules are not logged, but they should be. If a child of the rsync daemon dies with a signal, we should notice that when we reap it and log a message. Keep stderr and stdout properly separated (Debian #23626) Use a separate function for reporting errors; prefix it with "rsync:" or "rsync(remote)", or perhaps even "rsync(local generator): ". verbose output Indicate whether files are new, updated, or deleted At end of transfer, show how many files were or were not transferred correctly. -vv Explain *why* every file is transferred or not (e.g. "local mtime 123123 newer than 1283198") debugging of daemon Add an rsyncd.conf parameter to turn on debugging on the server. NICE ----------------------------------------------------------------- --no-detach and --no-fork options Very useful for debugging. Also good when running under a daemon-monitoring process that tries to restart the service when the parent exits. hang/timeout friendliness internationalization Change to using gettext(). Probably need to ship this for platforms that don't have it. Solicit translations. Does anyone care? Before we bother modifying the code, we ought to get the manual translated first, because that's possibly more useful and at any rate demonstrates desire. rsyncsh Write a small emulation of interactive ftp as a Pythonn program that calls rsync. Commands such as "cd", "ls", "ls *.c" etc map fairly directly into rsync commands: it just needs to remember the current host, directory and so on. We can probably even do completion of remote filenames.