Line data    Source code

       1             : /* Define an at-style functions like fstatat, unlinkat, fchownat, etc.
       2             :    Copyright (C) 2006 Free Software Foundation, Inc.
       3             : 
       4             :    This program is free software: you can redistribute it and/or modify
       5             :    it under the terms of the GNU General Public License as published by
       6             :    the Free Software Foundation; either version 3 of the License, or
       7             :    (at your option) any later version.
       8             : 
       9             :    This program is distributed in the hope that it will be useful,
      10             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12             :    GNU General Public License for more details.
      13             : 
      14             :    You should have received a copy of the GNU General Public License
      15             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      16             : 
      17             : /* written by Jim Meyering */
      18             : 
      19             : #define CALL_FUNC(F)                            \
      20             :   (AT_FUNC_USE_F1_COND                          \
      21             :     ? AT_FUNC_F1 (F AT_FUNC_POST_FILE_ARGS)     \
      22             :     : AT_FUNC_F2 (F AT_FUNC_POST_FILE_ARGS))
      23             : 
      24             : /* Call AT_FUNC_F1 or AT_FUNC_F2 (testing AT_FUNC_USE_F1_COND to
      25             :    determine which) to operate on FILE, which is in the directory
      26             :    open on descriptor FD.  If possible, do it without changing the
      27             :    working directory.  Otherwise, resort to using save_cwd/fchdir,
      28             :    then AT_FUNC_F?/restore_cwd.  If either the save_cwd or the restore_cwd
      29             :    fails, then give a diagnostic and exit nonzero.  */
      30             : int
      31      133394 : AT_FUNC_NAME (int fd, char const *file AT_FUNC_POST_FILE_PARAM_DECLS)
      32             : {
      33             :   struct saved_cwd saved_cwd;
      34             :   int saved_errno;
      35             :   int err;
      36             : 
      37      133394 :   if (fd == AT_FDCWD || IS_ABSOLUTE_FILE_NAME (file))
      38          16 :     return CALL_FUNC (file);
      39             : 
      40             :   {
      41             :     char buf[OPENAT_BUFFER_SIZE];
      42      133378 :     char *proc_file = openat_proc_name (buf, fd, file);
      43      133378 :     if (proc_file)
      44             :       {
      45      133378 :         int proc_result = CALL_FUNC (proc_file);
      46      133378 :         int proc_errno = errno;
      47      133378 :         if (proc_file != buf)
      48           0 :           free (proc_file);
      49             :         /* If the syscall succeeds, or if it fails with an unexpected
      50             :            errno value, then return right away.  Otherwise, fall through
      51             :            and resort to using save_cwd/restore_cwd.  */
      52      133378 :         if (0 <= proc_result)
      53           0 :           return proc_result;
      54      133378 :         if (! EXPECTED_ERRNO (proc_errno))
      55             :           {
      56           0 :             errno = proc_errno;
      57           0 :             return proc_result;
      58             :           }
      59             :       }
      60             :   }
      61             : 
      62      133378 :   if (save_cwd (&saved_cwd) != 0)
      63           0 :     openat_save_fail (errno);
      64             : 
      65      133378 :   if (fchdir (fd) != 0)
      66             :     {
      67           0 :       saved_errno = errno;
      68           0 :       free_cwd (&saved_cwd);
      69           0 :       errno = saved_errno;
      70           0 :       return -1;
      71             :     }
      72             : 
      73      133378 :   err = CALL_FUNC (file);
      74      133378 :   saved_errno = (err < 0 ? errno : 0);
      75             : 
      76      133378 :   if (restore_cwd (&saved_cwd) != 0)
      77           0 :     openat_restore_fail (errno);
      78             : 
      79      133378 :   free_cwd (&saved_cwd);
      80             : 
      81      133378 :   if (saved_errno)
      82      133378 :     errno = saved_errno;
      83      133378 :   return err;
      84             : }
      85             : #undef CALL_FUNC