1  /* listfile.c -- run a function in a specific directory
       2     Copyright (C) 2007-2022 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 <https://www.gnu.org/licenses/>.
      16  */
      17  
      18  /* This file was written by James Youngman, based on gnulib'c at-func.c.
      19   */
      20  
      21  /* config.h must be included first. */
      22  #include <config.h>
      23  
      24  /* system headers. */
      25  #include <errno.h>
      26  #include <stdarg.h>
      27  #include <sys/stat.h>
      28  
      29  /* gnulib headers. */
      30  #include "fcntl--.h"
      31  #include "openat.h"
      32  #include "save-cwd.h"
      33  
      34  /* find headers. */
      35  #include "dircallback.h"
      36  
      37  int
      38  run_in_dir (const struct saved_cwd *there,
      39  	    int (*callback)(void*), void *usercontext)
      40  {
      41    int err = -1;
      42    int saved_errno = 0;
      43    struct saved_cwd here;
      44    if (0 == save_cwd (&here))
      45      {
      46        if (0 == restore_cwd (there))
      47  	{
      48  	  err = callback(usercontext);
      49  	  saved_errno = (err < 0 ? errno : 0);
      50  	}
      51        else
      52  	{
      53  	  openat_restore_fail (errno);
      54  	}
      55  
      56        if (restore_cwd (&here) != 0)
      57  	openat_restore_fail (errno);
      58  
      59        free_cwd (&here);
      60      }
      61    else
      62      {
      63        openat_save_fail (errno);
      64      }
      65    if (saved_errno)
      66      errno = saved_errno;
      67    return err;
      68  }
      69  
      70  
      71  int
      72  run_in_dirfd (int dir_fd, int (*callback)(void*), void *usercontext)
      73  {
      74    if (dir_fd == AT_FDCWD)
      75      {
      76        return (*callback)(usercontext);
      77      }
      78    else
      79      {
      80        struct saved_cwd saved_cwd;
      81        int saved_errno;
      82        int err;
      83  
      84        if (save_cwd (&saved_cwd) != 0)
      85  	openat_save_fail (errno);
      86  
      87        if (fchdir (dir_fd) != 0)
      88  	{
      89  	  saved_errno = errno;
      90  	  free_cwd (&saved_cwd);
      91  	  errno = saved_errno;
      92  	  return -1;
      93  	}
      94  
      95        err = (*callback)(usercontext);
      96        saved_errno = (err < 0 ? errno : 0);
      97  
      98        if (restore_cwd (&saved_cwd) != 0)
      99  	openat_restore_fail (errno);
     100  
     101        free_cwd (&saved_cwd);
     102  
     103        if (saved_errno)
     104  	errno = saved_errno;
     105        return err;
     106      }
     107  }