Re: ia64 GNU/Linux pwd-long test failure in CVS coreutils

[Jim Meyering]

address@hidden (Bob Proulx) wrote:
> Jim Meyering wrote:
>> I should have created a directory whose abs. name length
>> is a little *larger* than 16K, not just smaller.
>>
>> Does it provoke the failed assertion if you change this line
>>
>>   size_t buf_len = 16 * 1024;
>>
>> to e.g., this:
>>
>>   size_t buf_len = 20 * 1024;
>
> Yes.  At 20k the mkdir succeeds, the chdir succeeds, the desired depth
> is reached and then the getcwd fails.  The getcwd fails with errno
> equal to 36 "File name too long" as expected.  It cleans up the
> created directory structure.
>
>   $ ls -log
>   total 36
>   -rwxr-xr-x  1 29101 Jun 18 11:54 getcwd-glibc-bug
>   -rw-r--r--  1  1180 Jun 18 11:56 getcwd-glibc-bug.c
>   $ ./getcwd-glibc-bug ; echo $?
>   4

Bummer.  I was hoping for a failed assertion.

Ohh....
I finally looked at the source for glibc's getcwd.c and see that
the bug is triggered only if you make *glibc* allocate the result buffer.

Would you please try one more time?

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/stat.h>

/* Don't get link errors because mkdir is redefined to rpl_mkdir.  */
#undef mkdir

#ifndef S_IRWXU
# define S_IRWXU 0700
#endif

#define TARGET_LEN (20 * 1024)

int
main ()
{
  char const *dir_name = "confdir-14B---";
  char *cwd;
  size_t initial_cwd_len;
  int fail = 0;
  size_t desired_depth;
  size_t d;

  cwd = getcwd (NULL, 0);
  if (cwd == NULL)
    exit (2);

  initial_cwd_len = strlen (cwd);
  free (cwd);
  desired_depth = ((TARGET_LEN - 1 - initial_cwd_len)
                   / (1 + strlen (dir_name)));
  for (d = 0; d < desired_depth; d++)
    {
      if (mkdir (dir_name, S_IRWXU) < 0 || chdir (dir_name) < 0)
        {
          fail = 3; /* Unable to construct deep hierarchy.  */
          break;
        }
    }

  cwd = getcwd (NULL, 0);
  if (cwd == NULL)
    fail = 4; /* getcwd failed.  This is ok, and expected.  */
  free (cwd);

  /* Call rmdir first, in case the above chdir failed.  */
  rmdir (dir_name);
  while (0 < d--)
    {
      if (chdir ("..") < 0)
        break;
      rmdir (dir_name);
    }

  exit (fail);
}