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

[Zenobiusz Kunegunda <zenobiusz.kunegunda@interia.pl>]

Od: "René Scharfe" <l.s.r@web.de>
Do: "Zenobiusz Kunegunda" <zenobiusz.kunegunda@interia.pl>; 
Wysłane: 22:31 Środa 2017-03-15
Temat: Re: fatal: Could not get current working directory: Permission denied | affected 2.10,2.11,2.12, but not 1.9.5 |

> 
> > Am 15.03.2017 um 10:44 schrieb Zenobiusz Kunegunda:
>> $ git bisect bad
>> 7333ed1788b4f2b162a35003044d77a716732a1f is the first bad commit
>> commit 7333ed1788b4f2b162a35003044d77a716732a1f
>> Author: René Scharfe 
>> 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:
> 
> 	#include 
> 	#include 
> 	#include 
> 	#include 
> 	#include 
> 
> 	int main(int argc, char **argv)
> 	{
> 		char buf[PATH_MAX];
> 		int last_errno = 0;
> 		size_t len;
> 
> 		for (len = 0; len <= PATH_MAX; len++) {
> 			errno = 0;
> 			getcwd(buf, len);
> 			if (errno != last_errno) {
> 				printf("len = %lu, errno = %d, %s\n",
> 					len, errno, strerror(errno));
> 			}
> 			last_errno = errno;
> 		}
> 		return 0;
> 	}
> 
> It runs getcwd(2) with buffer sizes from 0 to PATH_MAX and reports when 
> the error code changes along the way.  Let's call it test_getcwd.  And 
> here's what I get on FreeBSD 10.3:
> 
> 	$ mkdir /tmp/a
> 	$ cd /tmp/a
> 
> 	$ chmod 100 /tmp/a
> 	$ test_getcwd
> 	len = 0, errno = 22, Invalid argument
> 	len = 1, errno = 34, Result too large
> 	len = 7, errno = 0, No error: 0
> 
> 	$ chmod 000 /tmp/a
> 	$ test_getcwd
> 	len = 0, errno = 22, Invalid argument
> 	len = 1, errno = 34, Result too large
> 	len = 2, errno = 13, Permission denied
> 	len = 7, errno = 0, No error: 0
> 
> So if we don't have execute permission and our buffer is at least one 
> char long but still too small then we get EACCES (13).  If we don't have 
> read permissions and our buffer is big enough then the call succeeds. 
> strbuf_getcwd() expects to get ERANGE (34) and nothing else when the 
> buffer is too small.
> 
> I'd say it's a bug in FreeBSD -- reporting permission denied or success 
> based on the size of the supplied buffer makes no sense to me, at least.
> 
> The initial buffer size used by strbuf_getcwd() is 128, so you should be 
> fine as long as the absolute path to your repository is shorter than 
> that.  You should also be fine if you have execute permissions on the 
> directory.
> 
> And here I'm puzzled again -- you probably have sufficient permissions 
> set up for your user, right?  What does the test program report for your 
> problematic repository and its parent directories?
> 
> René
> 
> 

This program produces same errors I get from git in every directory . But no errors at all when run as root. Here is example when run as reular user.

   $ getcwdtest 
   len = 0, errno = 22, Invalid argument
   len = 1, errno = 34, Result too large
   len = 2, errno = 13, Permission denied
   len = 19, errno = 0, No error: 0
   $ mkdir testdir
   $ cd testdir/
   $ getcwdtest 
   len = 0, errno = 22, Invalid argument
   len = 1, errno = 34, Result too large
   len = 9, errno = 13, Permission denied
   len = 27, errno = 0, No error: 0

But when run as root there is no permission denied errors. Filesystem is ZFS.