Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Sun, Jul 6, 2014 at 7:56 PM, Linda A. Walsh  wrote:
>
> Ah
>
>
> I have my cygwin "cygdrive path prefix" set to "/"
>>
>>  mount -p
>
> Prefix  Type Flags
> /   user binmode
>
> You should be able to set it once:
>>
>>  mount -c /
>
>
> I also have my "cygwin" installed in "C:\"
> not "C:\cygwin".
>
> With those two changes, my cygwin and windows paths
> are identical (except for backslash or forward slash).
>
>
> Forgot about that -- have had it in root for over 10 years...since I
> first installed cygwin.
>
> FWIW -- I **might** call this a minor bug (or feature deficit).
> If you ahve native mode set  for the symlinks, then, I would
> argue that it shouldn't insert a "cygwin/c" in the path...
>
> Windows won't let you create a symlink to a non-existent path
> (you can on unix or linux), so when it fails for any reason --
> cygwin falls back to storing the link in a file.

Thanks for all your suggestions.

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Linda A. Walsh]

Ah


I have my cygwin "cygdrive path prefix" set to "/"

 mount -p

Prefix  Type Flags
/   user binmode

You should be able to set it once:

 mount -c /


I also have my "cygwin" installed in "C:\"
not "C:\cygwin".

With those two changes, my cygwin and windows paths
are identical (except for backslash or forward slash).


Forgot about that -- have had it in root for over 10 years...since I
first installed cygwin.

FWIW -- I **might** call this a minor bug (or feature deficit).
If you ahve native mode set  for the symlinks, then, I would
argue that it shouldn't insert a "cygwin/c" in the path...

Windows won't let you create a symlink to a non-existent path
(you can on unix or linux), so when it fails for any reason --
cygwin falls back to storing the link in a file.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Sat, Jul 5, 2014 at 11:24 PM, Linda A. Walsh  wrote:
>
> How are you setting your cygwin variable?

I was using export command:
export CYGWIN="system nodosfilewarning winsymlinks:native export"

>  It needs to be set before
> any cygwin processes start.

> I.e. in controlpanel->system->, advanced, environment variables.
>
> Best to set in System variables so all users will be sure to have it set.

Okay, I have tried by this way as well, but results are same.

Please see results:

edb@WIN-J9UR5I3UTSM /data
$ ls -l pg_tblspc/
total 1
lrwxrwxrwx 1 edb None 15 Jul  5 10:16 16386 -> /cygdrive/c/tbs

Now here point to note is that it is showing the link, even
though it is just a symbol file.

edb@WIN-J9UR5I3UTSM /data

$ cd pg_tblspc/
edb@WIN-J9UR5I3UTSM /data/pg_tblspc
$ ls -l
total 1
lrwxrwxrwx 1 edb None 15 Jul  5 10:16 16386 -> /cygdrive/c/tbs

edb@WIN-J9UR5I3UTSM /data/pg_tblspc
$ cd 16386
-bash: cd: 16386: No such file or directory


edb@WIN-J9UR5I3UTSM /data/pg_tblspc
$ cmd

Microsoft Windows [Version 6.2.9200]

(c) 2012 Microsoft Corporation. All rights reserved.


C:\cygwin64\data\pg_tblspc>ls -l
ls -l
total 1
lrwxrwxrwx 1 edb None 15 Jul  5 10:16 16386 -> /cygdrive/c/tbs

C:\cygwin64\data\pg_tblspc>dir

dir
 Volume in drive C has no label.
 Volume Serial Number is F049-7E4C

 Directory of C:\cygwin64\data\pg_tblspc

07/05/2014  10:16 AM  .
07/05/2014  10:16 AM  ..
   0 File(s)  0 bytes
   2 Dir(s)   1,508,360,192 bytes free

C:\cygwin64\data\pg_tblspc>

I have noticed one minor difference between the 2 versions of
CYGWIN as below, though it seems mine is more latest, but
don't know if it can cause such a behaviour difference.

>> > CYGWIN_NT-6.1 Athenae
>> CYGWIN_NT-6.2 WIN-J9UR5I3UTSM


At this moment, it is quite hard to believe that I am doing any
basic mistake due to which I am not able to see behaviour as yours,
do you think installation or something else needs to be taken care
in this regard?

With Regards,
Amit Kapila.

> Amit Kapila wrote:
>
>> On Sat, Jul 5, 2014 at 1:14 PM, Linda A. Walsh > wrote:
>> > Amit Kapila wrote
>> >
>> >>
>> >> Please extract in order as mentioned to ensure that symlink folder
>> >> gets extracted first.
>> >> Please check contents of C:\Data\pg_tblspc, ideally it should contain
>> >> symlink to C:\tbs.
>> >
>> > ---
>> > It appears to work as you are wanting it to (console output below).
>>
>> Thats great.
>>
>> > But I also note that if they are created in the wrong order (something
>> > that would work on linux).  -- then I get the behavior you mention:
>> >
>> > instead of a symlink, I get a file containing text:
>> >
>> > C:\data\pg_tblspc>hexdump -C 16386
>> >   21 3c 73 79 6d 6c 69 6e  6b 3e ff fe 63 00 3a 00
 |!..c.:.|
>> > 0010  5c 00 74 00 62 00 73 00  00 00
 |\.t.b.s...|
>> > 001a
>>
>> I am always getting file having contents as above.
>>
>> >
>> > This might have to do with the version of cygwin you have.
>> >
>> > You might make sure your cygwin is up to date -- as I vaguely remember
>> > somewhat older versions of 'cygwin' didn't create actual windows
>> > symlinks and hardlinks but created dummy files with the information
>> > in them (like you are seeing).  But that changed... maybe 2-4 years
ago?
>> >
>> > If you are running on a 64-bit windows, there is also a 64-bit
>> > cygwin that runs in native mode that gives some advantages over
>> > 32-bit  cygwin on a 64-bit machine (like 32-bit processes can't
>> > see the real C:\windows\system32, but are redirected to
C:\windows\syswow64
>> > syswow64 = windows[32] on windows64)
>> >
>> > you can tell which version you are running by running uname -a:
>> > CYGWIN_NT-6.1 Athenae 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64 Cygwin
>> >
>> > 32-bit cygwin would say:
>> > CYGWIN_NT-6.1-WOW64 Athenae 1.7.28(0.271/5/3) 2014-02-09 21:06 i686
Cygwin
>> >
>>
>> I am working Windows 64-bit and uname -a gives below info
>> on my m/c.
>>
>> CYGWIN_NT-6.2 WIN-J9UR5I3UTSM 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64
Cygwin
>>
>> I have downloaded cygwin for windows64-bit from below link:
>> https://www.cygwin.com/install.html
>>
>> Do I need to update my cygwin installation, any recommendation
>> for same?
>>
>> With Regards,
>> Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Linda A. Walsh]

How are you setting your cygwin variable?  It needs to be set before
any cygwin processes start.

I.e. in controlpanel->system->, advanced, environment variables.

Best to set in System variables so all users will be sure to have it set.

If that is where you are setting it, then I'm more stumped, but at this
point you might ask on the cygwin list, since it works with the same
software on my system. 


It sounds like cygwin is using the old-link creation for some reason...
the Env var not being set early enough would be one reason (as well
as wrong cygwin version, or windows version lower than Vista, or
too old cygwin version, but your cygwin looks recent enough), so if
you are setting the env var in your Window's system variables, then
I'm sorta stumped, other than to direct you to a better forum (cygwin)
for this ... am 90+% sure it's nothing to do with tar at this point.

Amit Kapila wrote:
On Sat, Jul 5, 2014 at 1:14 PM, Linda A. Walsh > wrote:

> Amit Kapila wrote
>
>>
>> Please extract in order as mentioned to ensure that symlink folder
>> gets extracted first.
>> Please check contents of C:\Data\pg_tblspc, ideally it should contain
>> symlink to C:\tbs.
>
> ---
> It appears to work as you are wanting it to (console output below).

Thats great.

> But I also note that if they are created in the wrong order (something
> that would work on linux).  -- then I get the behavior you mention:
>
> instead of a symlink, I get a file containing text:
>
> C:\data\pg_tblspc>hexdump -C 16386
>   21 3c 73 79 6d 6c 69 6e  6b 3e ff fe 63 00 3a 00 
 |!..c.:.|

> 0010  5c 00 74 00 62 00 73 00  00 00|\.t.b.s...|
> 001a

I am always getting file having contents as above.

>
> This might have to do with the version of cygwin you have.
>
> You might make sure your cygwin is up to date -- as I vaguely remember
> somewhat older versions of 'cygwin' didn't create actual windows
> symlinks and hardlinks but created dummy files with the information
> in them (like you are seeing).  But that changed... maybe 2-4 years ago?
>
> If you are running on a 64-bit windows, there is also a 64-bit
> cygwin that runs in native mode that gives some advantages over
> 32-bit  cygwin on a 64-bit machine (like 32-bit processes can't
> see the real C:\windows\system32, but are redirected to 
C:\windows\syswow64

> syswow64 = windows[32] on windows64)
>
> you can tell which version you are running by running uname -a:
> CYGWIN_NT-6.1 Athenae 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64 Cygwin
>
> 32-bit cygwin would say:
> CYGWIN_NT-6.1-WOW64 Athenae 1.7.28(0.271/5/3) 2014-02-09 21:06 i686 
Cygwin

>

I am working Windows 64-bit and uname -a gives below info
on my m/c.

CYGWIN_NT-6.2 WIN-J9UR5I3UTSM 1.7.30(0.272/5/3) 2014-05-23 10:36 
x86_64 Cygwin


I have downloaded cygwin for windows64-bit from below link:
https://www.cygwin.com/install.html

Do I need to update my cygwin installation, any recommendation
for same?

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Sat, Jul 5, 2014 at 1:14 PM, Linda A. Walsh  wrote:
> Amit Kapila wrote
>
>>
>> Please extract in order as mentioned to ensure that symlink folder
>> gets extracted first.
>> Please check contents of C:\Data\pg_tblspc, ideally it should contain
>> symlink to C:\tbs.
>
> ---
> It appears to work as you are wanting it to (console output below).

Thats great.

> But I also note that if they are created in the wrong order (something
> that would work on linux).  -- then I get the behavior you mention:
>
> instead of a symlink, I get a file containing text:
>
> C:\data\pg_tblspc>hexdump -C 16386
>   21 3c 73 79 6d 6c 69 6e  6b 3e ff fe 63 00 3a 00
 |!..c.:.|
> 0010  5c 00 74 00 62 00 73 00  00 00|\.t.b.s...|
> 001a

I am always getting file having contents as above.

>
> This might have to do with the version of cygwin you have.
>
> You might make sure your cygwin is up to date -- as I vaguely remember
> somewhat older versions of 'cygwin' didn't create actual windows
> symlinks and hardlinks but created dummy files with the information
> in them (like you are seeing).  But that changed... maybe 2-4 years ago?
>
> If you are running on a 64-bit windows, there is also a 64-bit
> cygwin that runs in native mode that gives some advantages over
> 32-bit  cygwin on a 64-bit machine (like 32-bit processes can't
> see the real C:\windows\system32, but are redirected to
C:\windows\syswow64
> syswow64 = windows[32] on windows64)
>
> you can tell which version you are running by running uname -a:
> CYGWIN_NT-6.1 Athenae 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64 Cygwin
>
> 32-bit cygwin would say:
> CYGWIN_NT-6.1-WOW64 Athenae 1.7.28(0.271/5/3) 2014-02-09 21:06 i686 Cygwin
>

I am working Windows 64-bit and uname -a gives below info
on my m/c.

CYGWIN_NT-6.2 WIN-J9UR5I3UTSM 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64
Cygwin

I have downloaded cygwin for windows64-bit from below link:
https://www.cygwin.com/install.html

Do I need to update my cygwin installation, any recommendation
for same?

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Linda A. Walsh]

Amit Kapila wrote


Please extract in order as mentioned to ensure that symlink folder
gets extracted first.
Please check contents of C:\Data\pg_tblspc, ideally it should contain
symlink to C:\tbs.

---
It appears to work as you are wanting it to (console output below).

But I also note that if they are created in the wrong order (something
that would work on linux).  -- then I get the behavior you mention:

instead of a symlink, I get a file containing text:

C:\data\pg_tblspc>hexdump -C 16386
  21 3c 73 79 6d 6c 69 6e  6b 3e ff fe 63 00 3a 00  
|!..c.:.|

0010  5c 00 74 00 62 00 73 00  00 00|\.t.b.s...|
001a

Working case follows:

 mkdir tbs

/> cd tbs
/tbs> tar xvaf /tmp/tars/16386.tar
PG_9.5_201406292/
PG_9.5_201406292/12135/
PG_9.5_201406292/12135/16387
/tbs> ll -R
.:
total 0
drwxrwxr-x+ 1 0 Jul  4 21:47 PG_9.5_201406292/

./PG_9.5_201406292:
total 0
drwxrwxr-x+ 1 0 Jul  4 21:47 12135/

./PG_9.5_201406292/12135:
total 0
-rw-rw-r-- 1 0 Jul  4 21:47 16387
/tbs> cd ..
/> mkdir data
/> cd data
/data> tar xaf /tmp/tars/base.tar
/data> ll
total 47
-rw-rw-r--+ 1 4 Jul  4 00:01 PG_VERSION
-rw---+ 1   206 Jul  4 21:47 backup_label
drwxrwxr-x+ 1 0 Jul  4 00:02 base/
drwxrwxr-x+ 1 0 Jul  5 00:18 global/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_clog/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_dynshmem/
-rw-rw-r--+ 1  4352 Jul  4 00:03 pg_hba.conf
-rw-rw-r--+ 1  1678 Jul  4 00:01 pg_ident.conf
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_llog/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_multixact/
drwxrwxr-x+ 1 0 Jul  4 21:45 pg_notify/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_replslot/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_serial/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_snapshots/
drwxrwxr-x+ 1 0 Jul  4 21:45 pg_stat/
drwxrwxr-x+ 1 0 Jul  4 21:47 pg_stat_tmp/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_subtrans/
drwxrwxr-x+ 1 0 Jul  4 21:46 pg_tblspc/
drwxrwxr-x+ 1 0 Jul  4 00:01 pg_twophase/
drwxrwxr-x+ 1 0 Jul  4 00:17 pg_xlog/
-rw-rw-r--+ 190 Jul  4 00:01 postgresql.auto.conf
-rw-rw-r--+ 1 21994 Jul  4 00:05 postgresql.conf
/data> ll pg_tblspc/
total 0
lrwxrwxrwx 1 4 Jul  4 21:46 16386 -> /tbs/
/data> cd pg_tblspc/
/data/pg_tblspc> ls
16386@
/data/pg_tblspc> cd 16386/
/data/pg_tblspc/16386> ls
PG_9.5_201406292/
/data/pg_tblspc/16386> cd ..
/data/pg_tblspc> cmd
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\data\pg_tblspc>dir
Volume in drive C is System Disk
Volume Serial Number is E889-68E4

Directory of C:\data\pg_tblspc

07/04/2014  09:46 PM  .
07/04/2014  09:46 PM  ..
07/04/2014  09:46 PM 16386 [C:\tbs]
  0 File(s)  0 bytes
  3 Dir(s)  218,077,290,496 bytes free

C:\data\pg_tblspc>
-

This might have to do with the version of cygwin you have.

You might make sure your cygwin is up to date -- as I vaguely remember
somewhat older versions of 'cygwin' didn't create actual windows
symlinks and hardlinks but created dummy files with the information
in them (like you are seeing).  But that changed... maybe 2-4 years ago?

If you are running on a 64-bit windows, there is also a 64-bit
cygwin that runs in native mode that gives some advantages over
32-bit  cygwin on a 64-bit machine (like 32-bit processes can't
see the real C:\windows\system32, but are redirected to C:\windows\syswow64
syswow64 = windows[32] on windows64)

you can tell which version you are running by running uname -a:
CYGWIN_NT-6.1 Athenae 1.7.30(0.272/5/3) 2014-05-23 10:36 x86_64 Cygwin

32-bit cygwin would say:
CYGWIN_NT-6.1-WOW64 Athenae 1.7.28(0.271/5/3) 2014-02-09 21:06 i686 Cygwin

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Linda A. Walsh]

Amit Kapila wrote:
On Thu, Jul 3, 2014 at 9:58 AM, Linda A. Walsh > wrote:

>
>
> Best bet might be to use cygwin to untar your files... it can create 
win-symlinks.


Do you know the specific utility in cygwin package which
I can use?

I had tried with bsdtar.exe available after installing cygwin,
it also doesn't extract symlinks from tar.

With Regards,
Amit Kapila.


tar-1.27.1
I created the file on linux using tar-1.26-19.1.2.x86_64, which is from:

URL : http://www.gnu.org/software/tar/
Summary : GNU implementation of tar ((t)ape (ar)chiver)

and...
/h> cp symtest.tar /tmp
/h> cd /tmp
/tmp> tar xaf symtest.tar
/tmp> cd symtest
/tmp/symtest> ls
one/  symone@  symthree@  symtwo@  three/  two/
/tmp/symtest> cd two
/tmp/symtest/two> ls
1@  2@  3@
/tmp/symtest/two> cat 1
file one
/tmp/symtest/two> cygcheck -f /bin/tar
tar-1.27.1-1
/tmp/symtest/two> cmd
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation.  All rights reserved.

C:\tmp\symtest\two>dir
Volume in drive C is System Disk
Volume Serial Number is E889-68E4

Directory of C:\tmp\symtest\two

07/04/2014  07:02 AM  .
07/04/2014  07:02 AM  ..
07/04/2014  07:02 AM  1 [..\one\1]
07/04/2014  07:02 AM  2 [..\one\2]
07/04/2014  07:02 AM  3 [..\one\3]
  3 File(s)  0 bytes
  2 Dir(s)  303,017,234,432 bytes free

C:\tmp\symtest\two>type 1
file one
C:\tmp\symtest\two>dir ..
Volume in drive C is System Disk
Volume Serial Number is E889-68E4

Directory of C:\tmp\symtest

07/04/2014  07:00 AM  .
07/04/2014  07:00 AM  ..
07/04/2014  07:01 AM  one
07/04/2014  07:00 AM symone [one]
07/04/2014  07:00 AM symthree [three]
07/04/2014  07:00 AM symtwo [two]
07/04/2014  07:00 AM  three
07/04/2014  07:02 AM  two
  0 File(s)  0 bytes
  8 Dir(s)  303,017,140,224 bytes free
=

It looks to me like win7 (and I believe vista) work fine with symlinks...

ON WINDOWS --

Caveats:

my "CYGWIN" env var is set to:

 echo $CYGWIN

system nodosfilewarning winsymlinks:native export
---

2) creating symlinks must be permitted in windows:

 fsutil behavior query symlinkevaluation

Local to local symbolic links are enabled.
Local to remote symbolic links are enabled.
Remote to local symbolic links are enabled.
Remote to remote symbolic links are enabled.

(use set to enable)

3) the symlinks must reside on an NTFS file system.

4)?? It may require some admin priv I don't know about,
as I'm in the admin group on my Winbox.



Note -- the target of a symlink can be anywhere:

I.e. in my win-homedir, my Documents directory points to my server:
law.Bliss> ll Doc*
lrwxrwxrwx  1 17 Nov  2  2013 Documents -> //Bliss/Documents/

(Bliss is my domain name... I thought it perfect [irony] for a win 
domain name)

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Thu, Jul 3, 2014 at 9:58 AM, Linda A. Walsh  wrote:
>
>
> Best bet might be to use cygwin to untar your files... it can create
win-symlinks.

Do you know the specific utility in cygwin package which
I can use?

I had tried with bsdtar.exe available after installing cygwin,
it also doesn't extract symlinks from tar.

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Linda A. Walsh]

Amit Kapila wrote:
On Mon, Jun 30, 2014 at 8:10 PM, Joerg Schilling 
> wrote:
> Amit Kapila > wrote:

> > On Mon, Jun 30, 2014 at 6:42 PM, Joerg Schilling <
> > joerg.schill...@fokus.fraunhofer.de 
> wrote:

> > > It will create copies as Win-DOS does not support symlnks.


Maybe not, but Windows has since Vista.  Maybe you should give up
Win-DOS?


> >
> > For my usecase, I need it to maintain symlinks even after it gets
> > untarred.  I have noticed that WinRar is able to maintain symlinks
> > after extraction.
>
> I am not sure how this should work, given the fact that Win-DOS does not
> correctly support symlinks.

Internally the software uses junction points as mentioned in below
link to create symlinks.
http://www.codeproject.com/KB/winsdk/junctionpoints.aspx


Technically, it should use 'mklink' which are windows symlinks.

Junctions are similar but are used to do mounts of file systems.
For most practical purposes, they should work 'fine'...


Cygwin walks all over Window's mountpoints and refuses to honor
them as mountpoint, so untaring things under cygwin will overwrite
mount points...

the mountd/linkd (types of junctions) are honored in one case in
cygwin, but not in the other.  Cygwin will use the native windows
symlinks when requested(an ENV var), to create symlinks.

Given that Windows (What is win-dos?  never heard of such -- I hope
you don't believe windows = dos -- as that'd be really wrong) is windows,
and it has symlinks, I don't see how you can claim windows symlinks don't
work.  If you want to claim they are not POSIX, that's a bit disingenuous as
Windows isn't POSIX.

Best bet might be to use cygwin to untar your files... it can create 
win-symlinks.


As for making multiple copies of files when untarring them?

That's not the same as creating links.

My font dir is 13.5 Meg if the links are ignored while only ~4-5M if linked.

(actually use hardlinks... which, BTW, windows also has).

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Mon, Jun 30, 2014 at 8:10 PM, Joerg Schilling <
joerg.schill...@fokus.fraunhofer.de> wrote:
> Amit Kapila  wrote:
> > On Mon, Jun 30, 2014 at 6:42 PM, Joerg Schilling <
> > joerg.schill...@fokus.fraunhofer.de> wrote:
> > > It will create copies as Win-DOS does not support symlnks.
> >
> > For my usecase, I need it to maintain symlinks even after it gets
> > untarred.  I have noticed that WinRar is able to maintain symlinks
> > after extraction.
>
> I am not sure how this should work, given the fact that Win-DOS does not
> correctly support symlinks.

Internally the software uses junction points as mentioned in below
link to create symlinks.
http://www.codeproject.com/KB/winsdk/junctionpoints.aspx

> See:
>
>
http://msdn.microsoft.com/en-us/library/windows/desktop/aa363866%28v=vs.85%29.aspx
>
> On the other side, are you sure that winrar supports tar archives?

No, it won't support tar format.  I want to mention about the case
when archive is created using WinRAR.  Even though WinRAR can
extract symlinks if archive is created originally with WinRAR,
it doesn't serve my usecase because it can't do so
if I try with archive created with tar which seems to be obvious.

I have mentioned about WinRAR, just to highlight the case that on
Windows symlinks can be extracted, so I think ideally it should be
possible for tar to be extracted even if it contains symlinks by some
other s/w on Windows.

> You may like to check to list this archive:
>
>
http://sourceforge.net/projects/s-tar/files/testscripts/pax-big-10g.tar.bz2/download
>
> and test whether the listing looks correctly, similar to this:
>
> 10737418240 -rw---  jes/glone Jun 15 23:18 2002 10g
>   0 -rw-r--r--  jes/glone Jun 15 16:53 2002 file
> star: 1048576 blocks + 3072 bytes (total of 10737421312 bytes =
10485763.00k).
>
> I would guess that winrar is unable to list both filenames.

Output on extracting with WinRAR
E:\basebackup>ls -l
total 5
-rw-r--r--1 edb  Administ0 Jun 16  2002 10g
-rw-r--r--1 edb  Administ  110 Jun 30 20:20 @PaxHeader
-rw-r--r--1 edb  Administ  458 Jun 26 19:02 RM31185.txt
-rw-r--r--1 edb  Administ 7808 Jun 17  2002 pax-big-10g.tar.bz2

Output on extracting with tar.exe
E:\basebackup>tar.exe -xvf pax-big-10g.tar.bz2
tar.exe: Record size = 2 blocks
tar.exe: Extended header size=10737418240 is out of range 0..2147483647
10g
tar.exe: Exiting with failure status due to previous errors

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Joerg Schilling]

Amit Kapila  wrote:

> On Mon, Jun 30, 2014 at 6:42 PM, Joerg Schilling <
> joerg.schill...@fokus.fraunhofer.de> wrote:
> > Amit Kapila  wrote:
> > > One more question, after using copysymlinks, will it retain the
> > > symlinks in Extracted data(folder)?
> >
> > It will create copies as Win-DOS does not support symlnks.
>
> For my usecase, I need it to maintain symlinks even after it gets
> untarred.  I have noticed that WinRar is able to maintain symlinks
> after extraction.

I am not sure how this should work, given the fact that Win-DOS does not 
correctly support symlinks.

See:

http://msdn.microsoft.com/en-us/library/windows/desktop/aa363866%28v=vs.85%29.aspx

On the other side, are you sure that winrar supports tar archives?

You may like to check to list this archive:


http://sourceforge.net/projects/s-tar/files/testscripts/pax-big-10g.tar.bz2/download

and test whether the listing looks correctly, similar to this:

10737418240 -rw---  jes/glone Jun 15 23:18 2002 10g
  0 -rw-r--r--  jes/glone Jun 15 16:53 2002 file
star: 1048576 blocks + 3072 bytes (total of 10737421312 bytes = 10485763.00k).

I would guess that winrar is unable to list both filenames.

Jörg

-- 
 EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
   j...@cs.tu-berlin.de(uni)  
   joerg.schill...@fokus.fraunhofer.de (work) Blog: 
http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Mon, Jun 30, 2014 at 6:42 PM, Joerg Schilling <
joerg.schill...@fokus.fraunhofer.de> wrote:
> Amit Kapila  wrote:
> > One more question, after using copysymlinks, will it retain the
> > symlinks in Extracted data(folder)?
>
> It will create copies as Win-DOS does not support symlnks.

For my usecase, I need it to maintain symlinks even after it gets
untarred.  I have noticed that WinRar is able to maintain symlinks
after extraction.

Thanks for all your help.

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Joerg Schilling]

Amit Kapila  wrote:

> > I send already a hint on how to do this using star.
>
> Thanks for your suggestion.
> I have tried to search on net to download this utility and found
> below link:
>  ftp://ftp.ffokus.gmd.de/pub/unix/cdrecord/alpha/win32/
>
> I am not able to get from above link, it says location doesn't
> exist.
>
> Could you let me know from where can I get this utility.

It is on Sourceforge now.

> One more question, after using copysymlinks, will it retain the
> symlinks in Extracted data(folder)?

It will create copies as Win-DOS does not support symlnks.

Jörg

-- 
 EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
   j...@cs.tu-berlin.de(uni)  
   joerg.schill...@fokus.fraunhofer.de (work) Blog: 
http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Sat, Jun 28, 2014 at 9:58 PM, Joerg Schilling <
joerg.schill...@fokus.fraunhofer.de> wrote:
>
> Amit Kapila  wrote:
>
> > I wanted to know that is there any tool on Windows which can
> > extract from tar when it contains symlinks.
>
> I send already a hint on how to do this using star.

Thanks for your suggestion.
I have tried to search on net to download this utility and found
below link:
 ftp://ftp.ffokus.gmd.de/pub/unix/cdrecord/alpha/win32/

I am not able to get from above link, it says location doesn't
exist.

Could you let me know from where can I get this utility.

One more question, after using copysymlinks, will it retain the
symlinks in Extracted data(folder)?

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Joerg Schilling]

Amit Kapila  wrote:

> I wanted to know that is there any tool on Windows which can
> extract from tar when it contains symlinks.

I send already a hint on how to do this using star.

Jörg

-- 
 EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
   j...@cs.tu-berlin.de(uni)  
   joerg.schill...@fokus.fraunhofer.de (work) Blog: 
http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Fri, Jun 27, 2014 at 6:23 PM, Joerg Schilling <
joerg.schill...@fokus.fraunhofer.de> wrote:
> Amit Kapila  wrote:
> Note that a specific CLI that works with gtar may not work with other tar
> implemenations exccept when this CLI is standard compliant.
>
> > The important point here is that the tar is created by using standard
> > tar format described in link below:
> > http://en.wikipedia.org/wiki/Tar_(computing)
>
> I believe that you are not talking about "tar" (see e.g.
>
https://sourceforge.net/p/schillix-on/schillix-on/ci/default/tree/usr/src/cmd/tar/
> for a source of the UNIX original tar implementation) but about gtar when
talking
> about tar.exe.

I am talking about GNU tar, please see below information:

tar (GNU tar) 1.22
Copyright (C) 2009 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later .
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Note that this software I am using to *untar* the already created
tar by some other software.
The other software creates tar file using format mentioned in the
link I have sent upthread (this software doesn't use tar command,
rather it forms the tar file via above format).

Now the problem is that when there are symlinks in the tar, extraction
(untar) of same doesn't work on Windows (I have tried using WinRAR,
GNU tar), if there are no symlinks, then every thing works fine.

I wanted to know that is there any tool on Windows which can
extract from tar when it contains symlinks.

With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Joerg Schilling]

Amit Kapila  wrote:

> On Fri, Jun 27, 2014 at 3:51 PM, Joerg Schilling <
> joerg.schill...@fokus.fraunhofer.de> wrote:
> > Win-DOS does not support symlinks. Even newer versions that claim to
> support
> > symlinks make a difference between links to files and links to
> directories.
> >
> > If you are not able to live with the Cygwin symlink emulation, I
> recommend to
> > use star and to tell it to make copies by using the option -copysymlinks
>
> Is it similar to what tar.exe -h option which can be used when
> we form the tar on folders/files?

Tar has no options (like e.g. -f and in special not -h). Tar instead implements 
key letters. The fact that many tar implementations support to use '-' in front 
of key letters does not mean that "tar -f ..." is a compliant usage.

Note that a specific CLI that works with gtar may not work with other tar 
implemenations exccept when this CLI is standard compliant.

> The important point here is that the tar is created by using standard
> tar format described in link below:
> http://en.wikipedia.org/wiki/Tar_(computing)

I believe that you are not talking about "tar" (see e.g. 
https://sourceforge.net/p/schillix-on/schillix-on/ci/default/tree/usr/src/cmd/tar/
 
for a source of the UNIX original tar implementation) but about gtar when 
talking 
about tar.exe. I am not sure how standard compliant gtar currently is and what 
you expect when using the term "standard tarformat), star is 
standard compliant with respect to the CLI and the archive format.

Star however implements extensions by allowing to use options and CLI 
extensions and by allowing other archive formats.



Jörg

-- 
 EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
   j...@cs.tu-berlin.de(uni)  
   joerg.schill...@fokus.fraunhofer.de (work) Blog: 
http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Amit Kapila]

On Fri, Jun 27, 2014 at 3:51 PM, Joerg Schilling <
joerg.schill...@fokus.fraunhofer.de> wrote:
> Win-DOS does not support symlinks. Even newer versions that claim to
support
> symlinks make a difference between links to files and links to
directories.
>
> If you are not able to live with the Cygwin symlink emulation, I
recommend to
> use star and to tell it to make copies by using the option -copysymlinks

Is it similar to what tar.exe -h option which can be used when
we form the tar on folders/files?

The important point here is that the tar is created by using standard
tar format described in link below:
http://en.wikipedia.org/wiki/Tar_(computing)

While forming tar, it uses link indicator as '2' as described in above
link and my requirement is to untar that on windows; the tar is
created using above format on Windows.


With Regards,
Amit Kapila.

Re: [Bug-tar] Regarding untaring tar files containing symlinks

[Joerg Schilling]

Amit Kapila  wrote:

> While working on one software, I face the requirement
> to untar a tar file on windows and it contains symlinks as
> well.
>
> While untaring it using tar -xvf abc.tar, it gives me below
> error for symlinks:
>
> tar.exe: xyz/1234: Cannot create symlink to `E:\\sym_loc': Not a directory
>
> The directory sym_loc already exists, is this a known
> limitation of tar on Windows?

Win-DOS does not support symlinks. Even newer versions that claim to support 
symlinks make a difference between links to files and links to directories.

If you are not able to live with the Cygwin symlink emulation, I recommend to 
use star and to tell it to make copies by using the option -copysymlinks

Jörg

-- 
 EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
   j...@cs.tu-berlin.de(uni)  
   joerg.schill...@fokus.fraunhofer.de (work) Blog: 
http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily