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 *
xfts_open(char * const * argv,int options,int (* compar)(const FTSENT **,const FTSENT **))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
cycle_warning_required(FTS const * fts,FTSENT const * ent)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 }
65