D. Allen [CGL]" <idallen@watcgl.waterloo.edu> (04/10/91)
For a nonexistent pathname "xxx" and a directory into which I do not
have permission to write "/", Ultrix issues the wrong error message:
On a MIPS system here:
1% ln -s xxx /
//xxx: Permission denied <- correct
2% touch /tmp/xxx
3% ln -s /tmp/xxx /
//xxx: Permission denied
On a 4.3 BSD system here:
1% ln -s xxx /
//xxx: Permission denied <- correct
2% touch /tmp/xxx
3% ln -s /tmp/xxx /
//xxx: Permission denied
On a SunOS 4.1 system here:
1% ln -s xxx /
ln: //xxx: Permission denied <- correct
2% touch /tmp/xxx
3% ln -s /tmp/xxx /
ln: //xxx: Permission denied
On Ultrix 4.1:
1% ln -s xxx /
xxx: No such file or directory <- What?!
2% touch /tmp/xxx
3% ln -s /tmp/xxx /
//xxx: Permission denied
The "No such file or directory" that Ultrix issues is not correct for #1.
The presence or absence of the link content should not affect the fact
that I don't have permission to make the symbolic link.
Ultrix should say, like everyone else, "Permission denied".
(It should also put the command name "ln:" in the error messages.)
Same problem on Ultrix 3.1 and Ultrix 3.1C. It gets marks for consistency.
--
-IAN! (Ian! D. Allen) idallen@watcgl.uwaterloo.ca idallen@watcgl.waterloo.edu
[129.97.128.64] Computer Graphics Lab/University of Waterloo/Ontario/Canadajv@mh.nl (Johan Vromans) (04/11/91)
In article <1991Apr9.194356.24156@watcgl.waterloo.edu> idallen@watcgl.waterloo.edu (Ian! D. Allen [CGL]) writes: > For a nonexistent pathname "xxx" and a directory into which I do not > have permission to write "/", Ultrix issues the wrong error message: >... > 1% ln -s xxx / > xxx: No such file or directory <- What?! >... > The "No such file or directory" that Ultrix issues is not correct for #1. > The presence or absence of the link content should not affect the fact > that I don't have permission to make the symbolic link. It doesn't. In this case, you deserve two error messages: ENOENT *AND* EPERM. > Ultrix should say, like everyone else, "Permission denied". I do not agree. To me, it is more logical to check source first. If you do not have a (valid) source, there is no need worrying about the destination. But I can imagine that checking destination first also has it points. > (It should also put the command name "ln:" in the error messages.) I agree on this one. Johan -- Johan Vromans jv@mh.nl via internet backbones Multihouse Automatisering bv uucp: ..!{uunet,hp4nl}!mh.nl!jv Doesburgweg 7, 2803 PL Gouda, The Netherlands phone/fax: +31 1820 62911/62500 ------------------------ "Arms are made for hugging" -------------------------
envbvs@epb7.lbl.gov (Brian V. Smith) (04/12/91)
In article <1991Apr11.080051.10756@pronto.mh.nl>, jv@mh.nl (Johan Vromans) writes: |> |> In article <1991Apr9.194356.24156@watcgl.waterloo.edu> |> idallen@watcgl.waterloo.edu (Ian! D. Allen [CGL]) writes: |> |> > For a nonexistent pathname "xxx" and a directory into which I do not |> > have permission to write "/", Ultrix issues the wrong error message: |> >... |> > 1% ln -s xxx / |> > xxx: No such file or directory <- What?! |> >... |> > The "No such file or directory" that Ultrix issues is not correct for #1. |> > The presence or absence of the link content should not affect the fact |> > that I don't have permission to make the symbolic link. |> |> It doesn't. In this case, you deserve two error messages: ENOENT |> *AND* EPERM. |> |> > Ultrix should say, like everyone else, "Permission denied". |> |> I do not agree. To me, it is more logical to check source first. If |> you do not have a (valid) source, there is no need worrying about the |> destination. |> But I can imagine that checking destination first also has it points. No, no, no. There is no reason that the source must exist when the symlink is created. That is one of the nice things about symlinks. It is simple string substitution. Try the following: ln -s xxx aaa It works fine even when xxx doesn't exist, as long as one has permission to create aaa. -- Brian V. Smith (bvsmith@lbl.gov) Lawrence Berkeley Laboratory I don't speak for LBL; they don't pay me enough for that.
jv@mh.nl (Johan Vromans) (04/13/91)
In article <11998@dog.ee.lbl.gov> envbvs@epb7.lbl.gov (Brian V. Smith) writes: | In article <1991Apr11.080051.10756@pronto.mh.nl>, jv@mh.nl (Johan Vromans) | writes: | |> [on a problem with "ln -s"] : | |> I do not agree. To me, it is more logical to check source first. If | |> you do not have a (valid) source, there is no need worrying about the | |> destination. | No, no, no. There is no reason that the source must exist when the symlink | is created. *IF* the semantics of symlinks do not require the source to be present, then I agree fully. In this case, you may consider EPERM to be an error, and ENOENT a warning. And errors take precedence over warnings. In the general situation of an input and output file, I thing checking input before output is intuitive. Johan -- Johan Vromans jv@mh.nl via internet backbones Multihouse Automatisering bv uucp: ..!{uunet,hp4nl}!mh.nl!jv Doesburgweg 7, 2803 PL Gouda, The Netherlands phone/fax: +31 1820 62911/62500 ------------------------ "Arms are made for hugging" -------------------------