1  /* xfts.c -- a wrapper for fts_open
       2  
       3     Copyright (C) 2003-2023 Free Software Foundation, Inc.
       4  
       5     This program is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU General Public License as published by
       7     the Free Software Foundation, either version 3 of the License, or
       8     (at your option) any later version.
       9  
      10     This program is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      13     GNU General Public License for more details.
      14  
      15     You should have received a copy of the GNU General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Written by Jim Meyering.  */
      19  
      20  #include <config.h>
      21  
      22  #include <stdlib.h>
      23  #include <errno.h>
      24  
      25  #include "assure.h"
      26  #include "xalloc.h"
      27  #include "xfts.h"
      28  
      29  /* Fail with a proper diagnostic if fts_open fails.  */
      30  
      31  FTS *
      32  xfts_open (char * const *argv, int options,
      33             int (*compar) (const FTSENT **, const FTSENT **))
      34  {
      35    FTS *fts = fts_open (argv, options | FTS_CWDFD, compar);
      36    if (fts == nullptr)
      37      {
      38        /* This can fail in two ways: out of memory or with errno==EINVAL,
      39           which indicates it was called with invalid bit_flags.  */
      40        affirm (errno != EINVAL);
      41        xalloc_die ();
      42      }
      43  
      44    return fts;
      45  }
      46  
      47  /* When fts_read returns FTS_DC to indicate a directory cycle,
      48     it may or may not indicate a real problem.  When a program like
      49     chgrp performs a recursive traversal that requires traversing
      50     symbolic links, it is *not* a problem.  However, when invoked
      51     with "-P -R", it deserves a warning.  The fts_options member
      52     records the options that control this aspect of fts's behavior,
      53     so test that.  */
      54  bool
      55  cycle_warning_required (FTS const *fts, FTSENT const *ent)
      56  {
      57  #define ISSET(Fts,Opt) ((Fts)->fts_options & (Opt))
      58    /* When dereferencing no symlinks, or when dereferencing only
      59       those listed on the command line and we're not processing
      60       a command-line argument, then a cycle is a serious problem. */
      61    return ((ISSET (fts, FTS_PHYSICAL) && !ISSET (fts, FTS_COMFOLLOW))
      62            || (ISSET (fts, FTS_PHYSICAL) && ISSET (fts, FTS_COMFOLLOW)
      63                && ent->fts_level != FTS_ROOTLEVEL));
      64  }