Date: Tue, 27 Jun 2000 02:30:13 -0700 (PDT) From: Bruce Evans <bde@zeta.org.au> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/19514: patch to prevent tail'ing directories Message-ID: <200006270930.CAA12364@freefall.freebsd.org>
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The following reply was made to PR bin/19514; it has been noted by GNATS. From: Bruce Evans <bde@zeta.org.au> To: kbyanc@posi.net Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: Re: bin/19514: patch to prevent tail'ing directories Date: Tue, 27 Jun 2000 19:22:55 +1000 (EST) On Mon, 26 Jun 2000 kbyanc@posi.net wrote: > >Description: > > tail(1) does not prevent the user from doing nonsensical things > like tail'ing directories. It is a feature of Unix utilities that they do what they are told to do. > Other commands, i.e. more(1) do. This This is a misfeature of more(1) :-). POSIX.2 (in the old draft that I have) specifically requires "tail -c" to accept arbitrary data. tail(1) without -c is only required to handle text files. head(1) is only required to handle text files. cat(1) is required to handle all types of files. > patch alerts the user when they try to tail a directory. In > addition, it also adds checks for reading symlink contents and > whiteout entries, however I can't imagine how either of these > scenarios would occur. At least the symlink case can't happen, so don't obfuscate the code checking for it. > --- usr.bin/tail/tail.c.orig Mon Jun 26 01:30:01 2000 > +++ usr.bin/tail/tail.c Mon Jun 26 01:38:38 2000 > @@ -171,6 +171,16 @@ > ierr(); > continue; > } > + if (sb.st_mode & S_IFDIR) > + errx(1, "%s is a directory", fname); Exiting for a non-error is a bug. The current tail(1) doesn't even exit for errors on individual files. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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