Re: fatal: Could not get current working directory: Permission denied | affected 2.10,2.11,2.12, but not 1.9.5 |

From: Stefan Beller <sbeller@google.com>
Date: Mar 17, 2017, 19:45 UTC
Message-ID: <CAGZ79kbpPBN21mbN2F20ikr6dXrKEcY=msqymaG8TOujeQF0jw@mail.gmail.com>
In-Reply-To: <f6588ace-eecc-118d-ef26-70bc21dcc4d4@web.de>

On Fri, Mar 17, 2017 at 12:34 PM, René Scharfe <l.s.r@web.de> wrote:

Show 35 quoted lines

> Am 15.03.2017 um 22:30 schrieb René Scharfe:
>> Am 15.03.2017 um 10:44 schrieb Zenobiusz Kunegunda:
>>> $ git bisect bad
>>> 7333ed1788b4f2b162a35003044d77a716732a1f is the first bad commit
>>> commit 7333ed1788b4f2b162a35003044d77a716732a1f
>>> Author: René Scharfe <l.s.r@web.de>
>>> Date:   Mon Jul 28 20:26:40 2014 +0200
>>>
>>>     setup: convert setup_git_directory_gently_1 et al. to strbuf
>>
>> That's what I half-suspected, and I think by now I got an idea.  Here's
>> a test program:
>
> And here's a patch for letting strbuf_getcwd() use the same getcwd(3)
> extension that pwd(1) uses.  It avoids the need to guess the path's
> length and thus reduces the chance of stumbling over strange error
> codes.  I wonder if it helps in your case.
>
> René
>
> ---
>  strbuf.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/strbuf.c b/strbuf.c
> index ace58e7367..4c02801edd 100644
> --- a/strbuf.c
> +++ b/strbuf.c
> @@ -442,6 +442,14 @@ int strbuf_getcwd(struct strbuf *sb)
>  {
>         size_t oldalloc = sb->alloc;
>         size_t guessed_len = 128;
> +       char *cwd;
> +
> +       cwd = getcwd(NULL, 0);

from my local man pages:

  As  an extension to the POSIX.1-2001 standard, Linux (libc4, libc5,
glibc) getcwd()
  allocates the buffer dynamically using malloc(3) if buf is NULL.  In
this case, the
  allocated buffer has the length size unless size is zero, when buf
is allocated as big
  as necessary.  The caller should free(3) the returned buffer.

This sounds specific to Linux (though I am reading Linux man pages, which claim this; Also it seems I might have misread it as it also states "The pathname is returned as the function result and via the argument buf, if present.").

Looking further:

  These functions are often used to save the location of the current
  working directory for the purpose of returning to it later.  Opening the
  current directory (".")  and  calling  fchdir(2)  to return is
usually a faster
  and more reliable alternative when sufficiently many file descriptors are
  available, especially on platforms other than Linux.

Not sure if that opens another door here?

Thanks, Stefan