Re: [Mingw-msys] passing "-" on command line in MSYS sh

[Keith M. <kei...@to...>]

John Vanderberg wrote, quoting me:
>> Tomer Ben-Chen wrote:
>>> I checked again, it is definitely a bug. It happens only when
>>> calling the program from a relative location (for example, up
>>> a directory - see below).
>>
>> Indeed, I can reproduce this, but only when the relative path is
>> composed *entirely* of `..' references.
>>
>>> I'm using MSYS version 1.0.10 ...
>>
>> As am I ...
>
> I can reproduce this as well on 1.0.11(0.46/3/2) 2004-04-30.  I
> have found a workaround, but first...
>
> $ ../dumpargs.exe - -abc
> argv[0]: c:\workspace\dumpargs.exe
> argv[1]: -C:/msys/1.0/dumpa
> argv[2]: -abc
>
> $ cp ../dumpargs.exe ../printargs.exe
>
> $ ../printargs - -abc
> argv[0]: c:\workspace\printargs.exe
> argv[1]: -C:/msys/1.0/print
> argv[2]: -abc
>
> And here is where the problem goes away...
>
> $ ../printargs.exe - -abc
> argv[0]: c:\workspace\printargs.exe
> argv[1]: -
> argv[2]: -abc
>
> And by reduce the length of the command, I can make it come back
> again (whee...)

Ok, thanks John.  I see something similar with 1.0.10:

  $ cd foo
  $ cp ../dumpargs.exe ../a.exe
  $ a=a
  $ until test $a = aaaaaaaaaaaaaaaa
  > do
  >   echo \$ ../$a - -abc
  >   ../$a - -abc
  >   mv ../$a.exe ../a$a.exe
  >   a=a$a
  > done; rm ../aaa*.exe
  $ ../a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -a:/
  argv[2]: -abc
  $ ../aa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aa.exe
  argv[1]: -D:/MSYS/1.0/aa
  argv[2]: -abc
  $ ../aaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaa.exe
  argv[1]: -D:/MSYS/1.0/aaa
  argv[2]: -abc
  $ ../aaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaa
  argv[2]: -abc
  $ ../aaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaaaaa.exe
  argv[1]: -D:/MSYS/1.0/aaaaa
  argv[2]: -abc
  $ ../aaaaaaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaaaaaa.exe
  argv[1]: -
  argv[2]: -abc
  $ ../aaaaaaaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaaaaaaa.exe
  argv[1]: -
  argv[2]: -abc
  $ ../aaaaaaaaaaaaaaa - -abc
  argv[0]: D:\MSYS\1.0\home\keith\aaaaaaaaaaaaaaa.exe
  argv[1]: -
  argv[2]: -abc

So, it seems that:

-  for very short command names, the initial `-' argv[1] gets
   extended, by appending `<msys-root>/<basename argv[0]>'

-  as the length of the executable name increases, the extra chars
   appended to argv[1] are truncated after some fixed length

-  as the length of the name increases further, to exceed 12 chars,
   the value of argv[1] is no longer corrupted.

And, BTW, my earlier statement that this anomaly only appears if the
relative path is composed only of `..' entities wasn't true:

  $ mkdir -p a/b
  $ cp dumpargs.exe a/a.exe
  $ cd a/b
  $ ../../a/a - -abc

seems to expose it, while

  $ cd foo
  $ ../../keith/dumpargs - -abc

makes the command name long enough to conceal it.

> So, it looks like it is the length of the command name that triggers
> this bug.

Indeed, there does appear to be some correlation.

> fyi, this looks very similar to the problem I reported in July last
> year:
>
> http://lists.zerezo.com/mingw-msys/msg00525.html
>
> My workaround was to use double-slashes instead of single-slashes;
> perhaps a similar workaround can be found for this problem...
>
> $ ../dumpargs.exe - -abc
> argv[0]: c:\workspace\dumpargs.exe
> argv[1]: -C:/msys/1.0/dumpa
> argv[2]: -abc
>
> $ ..//dumpargs.exe - -abc
> argv[0]: c:\workspace\dumpargs.exe
> argv[1]: -
> argv[2]: -abc
>
> Look at that ... double-slashes and the problem disappears :-)

Nope.  While there does appear to be some effect, that isn't sufficient,
even as a work around -- sorry, but...

  $ pwd
  /home/keith/foo
  $ cp ../dumpargs.exe ../a.exe
  $ a=a
  $ until test $a = ////////////////
  > do
  >   echo \$ ..${a}a - -abc
  >   eval ..${a}a - -abc
  >   a=$a/
  > done; rm ../a.exe
  $ ../a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -a:/
  argv[2]: -abc
  $ ..//a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/a
  argv[2]: -abc
  $ ..///a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -//a
  argv[2]: -abc
  $ ..////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -///a
  argv[2]: -abc
  $ ../////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -////a
  argv[2]: -abc
  $ ..//////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ..///////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ..////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ../////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ..//////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ..///////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ..////////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -/////
  argv[2]: -abc
  $ ../////////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -
  argv[2]: -abc
  $ ..//////////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -
  argv[2]: -abc
  $ ..///////////////a - -abc
  argv[0]: D:\MSYS\1.0\home\keith\a.exe
  argv[1]: -
  argv[2]: -abc

Regards,
Keith.