On Fri, Jun 26, 2009 at 05:40, Jim Meyering<j...@meyering.net> wrote: > enh wrote: > >> if i create a dangling symbolic link within a tree, "chown -RH >> top-of-tree" gets me a "cannot dereference" error. >> >> STEPS TO REPRODUCE: >> >> cd /tmp >> mkdir chown-test >> cd chown-test >> ln -s poop parp >> cd .. >> chown -RH :nogroup chown-test > > Thanks for taking the time to report that. > However, I think you have a misunderstanding. > >> ACTUAL OUTPUT: >> >> chown: cannot dereference `chown-test/parp': No such file or directory >> chown: changing group of `chown-test': Operation not permitted >> >> EXPECTED BEHAVIOR: >> >> i don't think chown should try to dereference the dangling symbolic link. > > You're confusing the hierarchy-traversal options (-H, -L, -P, and whether > they dereference symlinks) and an independent option that determines, > once a file system object has been selected, whether chown should > operate on it or on whatever it references if it's a symlink. > > Maybe you didn't notice the description of the --dereference option? > > --dereference > affect the referent of each symbolic link (this is the > default), rather than the symbolic link itself > > -h, --no-dereference > affect each symbolic link instead of any referenced file > (useful only on systems that can change the ownership of a > symlink) > >> looking at the source, i think affect_symlink_referent should be >> false. i think the code in chown.c's main() should be more like the >> code in chcon.c's main(), but that both should be changed to test >> (bit_flags & FTS_PHYSICAL) rather than (bit_flags == FTS_PHYSICAL), >> because -H sets bit_flags to FTS_COMFOLLOW | FTS_PHYSICAL. >> >> alternatively, i could have completely misunderstood the intended >> behavior of -RH. but it seems to me like -H should cause only symbolic >> links explicitly named on the command-line to be dereferenced. > > This is described in the "info" documentation, > i.e., what you get when you run "info coreutils chown". > If that's not clear enough, specific suggestions for improvement > are most welcome. > > It cross-references this section: > > 2.9 Traversing symlinks > ======================= > > The following options modify how `chown' and `chgrp' traverse a > hierarchy when the `--recursive' (`-R') option is also specified. If > more than one of the following options is specified, only the final one > takes effect. These options specify whether processing a symbolic link > to a directory entails operating on just the symbolic link or on all > files in the hierarchy rooted at that directory. > > These options are independent of `--dereference' and > `--no-dereference' (`-h'), which control whether to modify a symlink or > its referent.
i think this paragraph, had it been in the man page, would have prevented my confusion. putting -H, -L, and -P next to --dereference and --no-dereference (as with -h on the Mac OS man page) _might_ have helped, but your "these are traversal, those are reference" paragraph would have been perfect. thanks! now all i need to do is cope with ancient versions of GNU chown that don't support -RH in conjunction with -h... ;-) --elliott > `-H' > If `--recursive' (`-R') is specified and a command line argument > is a symbolic link to a directory, traverse it. > > `-L' > In a recursive traversal, traverse every symbolic link to a > directory that is encountered. > > `-P' > Do not traverse any symbolic links. This is the default if none > of `-H', `-L', or `-P' is specified. > -- Elliott Hughes - http://who/enh - http://jessies.org/~enh/ _______________________________________________ Bug-coreutils mailing list Bug-coreutils@gnu.org http://lists.gnu.org/mailman/listinfo/bug-coreutils
