text: /* Work around unlinkat bugs on Solaris 9 and Hurd.
  
     Copyright (C) 2009-2013 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  /* Written by Eric Blake.  */
  
  #include <mingle/config.h>
  
  #include <unistd.h>
  
  #include <errno.h>
  #include <fcntl.h>
  #include <string.h>
  #include <sys/stat.h>
  
  #include <stdlib.h>
  
  #include "dosname.h"
  #include "openat.h"
  
  #if HAVE_UNLINKAT
  
  # undef unlinkat
  
  /* unlinkat without AT_REMOVEDIR does not honor trailing / on Solaris
     9.  Solve it in a similar manner to unlink.  Hurd has the same
     issue. */
  
  int
  rpl_unlinkat (int fd, char const *name, int flag)
  {
    size_t len;
    int result = 0;
    /* rmdir behavior has no problems with trailing slash.  */
    if (flag & AT_REMOVEDIR)
      return unlinkat (fd, name, flag);
  
    len = strlen (name);
    if (len && ISSLASH (name[len - 1]))
      {
        /* See the lengthy comment in unlink.c why we disobey the POSIX
           rule of letting unlink("link-to-dir/") attempt to unlink a
           directory.  */
        struct stat st;
        result = lstatat (fd, name, &st);
        if (result == 0)
          {
            /* Trailing NUL will overwrite the trailing slash.  */
            char *short_name = malloc (len);
            if (!short_name)
              {
                errno = EPERM;
                return -1;
              }
            memcpy (short_name, name, len);
            while (len && ISSLASH (short_name[len - 1]))
              short_name[--len] = '\0';
            if (len && (lstatat (fd, short_name, &st) || S_ISLNK (st.st_mode)))
              {
                free (short_name);
                errno = EPERM;
                return -1;
              }
            free (short_name);
          }
      }
    if (!result)
      result = unlinkat (fd, name, flag);
    return result;
  }
  
  #else /* !HAVE_UNLINKAT */
  
  /* Replacement for Solaris' function by the same name.
     <http://www.google.com/search?q=unlinkat+site:docs.sun.com>
     First, try to simulate it via (unlink|rmdir) ("/proc/self/fd/FD/FILE").
     Failing that, simulate it via save_cwd/fchdir/(unlink|rmdir)/restore_cwd.
     If either the save_cwd or the restore_cwd fails (relatively unlikely),
     then give a diagnostic and exit nonzero.
     Otherwise, this function works just like Solaris' unlinkat.  */
  
  # define AT_FUNC_NAME unlinkat
  # define AT_FUNC_F1 rmdir
  # define AT_FUNC_F2 unlink
  # define AT_FUNC_USE_F1_COND AT_REMOVEDIR
  # define AT_FUNC_POST_FILE_PARAM_DECLS , int flag
  # define AT_FUNC_POST_FILE_ARGS        /* empty */
  # include "at-func.c"
  # undef AT_FUNC_NAME
  # undef AT_FUNC_F1
  # undef AT_FUNC_F2
  # undef AT_FUNC_USE_F1_COND
  # undef AT_FUNC_POST_FILE_PARAM_DECLS
  # undef AT_FUNC_POST_FILE_ARGS
  
  #endif /* !HAVE_UNLINKAT */
  