joey@darkstar:~/tmp/y>ln -s /etc/passwd README
joey@darkstar:~/tmp/y>ls
README@
joey@darkstar:~/tmp/y>wget -O foo ftp://ftp.funet.fi/pub/Linux/mirrors/debian/README
--2015-05-05 13:17:22--  ftp://ftp.funet.fi/pub/Linux/mirrors/debian/README
           => ‘foo’
Resolving ftp.funet.fi (ftp.funet.fi)... 193.166.3.2, 2001:708:10:9::20:2
Connecting to ftp.funet.fi (ftp.funet.fi)|193.166.3.2|:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done.    ==> PWD ... done.
==> TYPE I ... done.  ==> CWD (1) /pub/Linux/mirrors/debian ... done.
==> SIZE README ... 1495
==> PASV ... done.    ==> RETR README ... done.
Length: 1495 (1.5K) (unauthoritative)

README              100%[=====================>]   1.46K  5.45KB/s   in 0.3s

2015-05-05 13:17:28 (5.45 KB/s) - ‘foo’ saved [1495]

joey@darkstar:~/tmp/y>ls
foo

Doesn't happen if README is a file rather than a symlink, doesn't happen
when using http. The ftp downloader apparently has a bug..

URL:
  <http://savannah.gnu.org/bugs/?45037>

                 Summary: wget -O foo
ftp://ftp.funet.fi/pub/Linux/mirrors/debian/README deletes README symlink
                 Project: GNU Wget
            Submitted by: nok
            Submitted on: Mi 06 Mai 2015 15:36:34 CEST
                Category: Program Logic
                Severity: 3 - Normal
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
         Originator Name:
        Originator Email:
             Open/Closed: Open
         Discussion Lock: Any
                 Release: 1.16.3
        Operating System: GNU/Linux
         Reproducibility: Every Time
           Fixed Release: None
         Planned Release: None
              Regression: None
           Work Required: None
          Patch Included: No

forwarded 784348 https://savannah.gnu.org/bugs/?45037
found 784348 1.16.3-2
tags 784348 upstream
thanks

Hello Joey,

Am Dienstag, den 05.05.2015, 13:18 -0400 schrieb Joey Hess:
...

Thanks for your report. It is reproducible with the latest version
1.16.3 and I forwarded it to the upstream bugtracker.

Regards

	Noël

Update of bug #45037 (project wget):

                  Status:                    None => Confirmed

Follow-up Comment #1, bug #45037 (project wget):

slightly related bug..

$ ln -s /etc/passwd README

$ wget  -O README http://foo.bar
README: Permission denied

Follow-up Comment #2, bug #45037 (project wget):

Use -d to get
Unlinking README (symlink).

In ftp.c you will find those lines:
  /* Remove it if it's a link.  */
  remove_link (con->target);

This is done by purpose (I just can guess why: not to overwrite the content
the link points to).

The question is: is it a bug or a feature ? Should we just document this
behaviour (maybe it already is).

Follow-up Comment #3, bug #45037 (project wget):

It's clearly a bug. If we are downloading README to local file foo, there's no
reason to remove the local symlink README.

When we want to save into a name where there's currently a symlink,
consistency with shell > would dictate just to follow the link on writing, but
as that may lead to security issues, replacing with a file may also be
acceptable.

I agree. This is definitely a bug.
My guess is, we should default to shell like behaviour and provide a command
line option to instead replace the file, if the user wishes so.

Given that this is a clearly documented feature of Wget, that -O is supposed to
work as shell redirection, I think it should not pose too many issues. Yes,
there is the security risk where another file may be overwritten, but I think
the user should be careful about those.

This definitely is a bug. I've attached a small fix for this particular issue.
If no one has any issues with it, I'll push it in a day.

Although, I think we should also look into the issue Giuseppe found, and also
the point that Angel raised about compatibility with shell like redirection.

Hi Darshit,

your patch doesn't work as expected.

$ cat abc >xxx
$ ln -s xxx foo
$ ln -s /etc/passwd README
$ ../src/wget -O foo ftp://ftp.funet.fi/pub/Linux/mirrors/debian/README
...

$ ls -la
lrwxrwxrwx 1 oms users   11 May  7 09:28 README -> /etc/passwd
-rw-r--r-- 1 oms users 1495 May  7 09:30 xxx

'foo' doesn't exist and 'xxx' has been overwritten !!!

Regards, Tim

Aah! It was a quick patch I wrote and had tested only one scenario.
Which is why I wanted some reviews before pushing it.

Seems like it'll take slightly more effort to fix this. I'll take a
look again today evening.

I was thinking in a recursive download creating a symlink and then
following it, using the same code path. If the user explicitely
requested wget -O symlink, it's the user responsability.