lib/xfts.c

   1 /* xfts.c -- a wrapper for fts_open
   2
   3    Copyright (C) 2003, 2005-2007, 2009-2011 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 <http://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Jim Meyering.  */
  19
  20 #include <config.h>
  21
  22 #include <stdbool.h>
  23 #include <stdlib.h>
  24 #include <errno.h>
  25 #include <assert.h>
  26
  27 #include "xalloc.h"
  28 #include "xfts.h"
  29
  30 /* Fail with a proper diagnostic if fts_open fails.  */
  31
  32 FTS *
  33 xfts_open (char * const *argv, int options,
  34            int (*compar) (const FTSENT **, const FTSENT **))
  35 {
  36   FTS *fts = fts_open (argv, options | FTS_CWDFD, compar);
  37   if (fts == NULL)
  38     {
  39       /* This can fail in two ways: out of memory or with errno==EINVAL,
  40          which indicates it was called with invalid bit_flags.  */
  41       assert (errno != EINVAL);
  42       xalloc_die ();
  43     }
  44
  45   return fts;
  46 }
  47
  48 /* When fts_read returns FTS_DC to indicate a directory cycle,
  49    it may or may not indicate a real problem.  When a program like
  50    chgrp performs a recursive traversal that requires traversing
  51    symbolic links, it is *not* a problem.  However, when invoked
  52    with "-P -R", it deserves a warning.  The fts_options member
  53    records the options that control this aspect of fts's behavior,
  54    so test that.  */
  55 bool
  56 cycle_warning_required (FTS const *fts, FTSENT const *ent)
  57 {
  58 #define ISSET(Fts,Opt) ((Fts)->fts_options & (Opt))
  59   /* When dereferencing no symlinks, or when dereferencing only
  60      those listed on the command line and we're not processing
  61      a command-line argument, then a cycle is a serious problem. */
  62   return ((ISSET (fts, FTS_PHYSICAL) && !ISSET (fts, FTS_COMFOLLOW))
  63           || (ISSET (fts, FTS_PHYSICAL) && ISSET (fts, FTS_COMFOLLOW)
  64               && ent->fts_level != FTS_ROOTLEVEL));
  65 }