1/*	$OpenBSD: nftw.c,v 1.2 2003/07/21 21:15:32 millert Exp $	*/
2
3/*
4 * Copyright (c) 2003 Todd C. Miller <Todd.Miller@courtesan.com>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 *
18 * Sponsored in part by the Defense Advanced Research Projects
19 * Agency (DARPA) and Air Force Research Laboratory, Air Force
20 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
21 */
22
23#if defined(LIBC_SCCS) && !defined(lint)
24static const char rcsid[] = "$OpenBSD: nftw.c,v 1.2 2003/07/21 21:15:32 millert Exp $";
25#endif /* LIBC_SCCS and not lint */
26
27#include <stdio.h>
28#include <sys/cdefs.h>
29#include <sys/types.h>
30#include <sys/stat.h>
31#include <errno.h>
32#include <fts.h>
33#include <ftw.h>
34#include <limits.h>
35#include <fcntl.h>
36#include <stdlib.h>
37#include <string.h>
38#include <unistd.h>
39
40static int
41both_ftw(const char *path,
42	int (*ofn)(const char *, const struct stat *, int),
43	int (*nfn)(const char *, const struct stat *, int, struct FTW *),
44	int nfds, int ftwflags)
45{
46	const char *paths[2];
47	struct FTW ftw;
48	FTSENT *cur;
49	FTS *ftsp = NULL;
50	int ftsflags, fnflag, error, postorder, sverrno;
51	int cwd_fd = -1; /* cwd_fd != -1 means call chdir a lot */
52
53#if __DARWIN_UNIX03
54	/* Macro to skip the mount point itself in UNiX03 mode, in legcy
55	  mode the mount point is returned, but we don't decend into it */
56#define SKIP_MOUNT if ((ftwflags & FTW_MOUNT) \
57      && cur->fts_statp->st_dev != path_stat.st_dev) { \
58	continue; \
59    }
60#else
61#define SKIP_MOUNT
62#endif
63
64	/* XXX - nfds is currently unused */
65	if (nfds < 1 || nfds > OPEN_MAX) {
66		errno = EINVAL;
67		error = -1;
68		goto done;
69	}
70
71	ftsflags = FTS_COMFOLLOW;
72	if (!(ftwflags & FTW_CHDIR))
73		ftsflags |= FTS_NOCHDIR;
74	if (ftwflags & FTW_MOUNT)
75		ftsflags |= FTS_XDEV;
76	if (ftwflags & FTW_PHYS) {
77		ftsflags |= FTS_PHYSICAL;
78	} else {
79		ftsflags |= FTS_LOGICAL;
80	}
81	postorder = (ftwflags & FTW_DEPTH) != 0;
82
83	/* We have been requested to change directories, and fts doesn't
84	  always do it (never for FTS_LOGICAL, and sometimes not for
85	  FTS_PHYSICAL) */
86	if (ftwflags & FTW_CHDIR) {
87	    cwd_fd = open(".", O_RDONLY, 0);
88	    if (cwd_fd < 0) {
89		error = -1;
90		goto done;
91	    }
92	    /* Prevent problems if fts ever starts using chdir when passed
93	      FTS_PHYSICAL */
94	    ftsflags |= FTS_NOCHDIR;
95	}
96
97#if __DARWIN_UNIX03
98	struct stat path_stat;
99
100	/* UNIX03 requires us to return -1/errno=ELOOP if path
101	  is a looping symlink; fts_open is succesful and fts_read
102	  gives us FTS_NS which isn't very useful, in fact we get
103	  pretty much the same behaviour for ENAMETOOLONG, ENOENT,
104	  ENOTDIR, and EACCES */
105	{
106	    int rc = stat(path, &path_stat);
107	    if (rc < 0
108	      && (errno == ELOOP || errno == ENAMETOOLONG || errno == ENOENT
109	      || errno == ENOTDIR || errno == EACCES)) {
110		    error = -1;
111		    goto done;
112	    }
113	    if (rc >= 0 && nfn) {
114		if (!S_ISDIR(path_stat.st_mode)) {
115		    errno = ENOTDIR;
116		    error = -1;
117		    goto done;
118		}
119	    }
120	}
121#endif
122	paths[0] = path;
123	paths[1] = NULL;
124	ftsp = fts_open((char * const *)paths, ftsflags, NULL);
125	if (ftsp == NULL) {
126	    error = -1;
127	    goto done;
128	}
129	error = 0;
130	while ((cur = fts_read(ftsp)) != NULL) {
131		switch (cur->fts_info) {
132		case FTS_D:
133			if (postorder)
134				continue;
135			SKIP_MOUNT;
136			/* we will get FTS_DNR next (this is not an issue for
137			  FTS_DP, only FTS_D) */
138			if (access(cur->fts_path, R_OK) != 0)
139			    continue;
140			fnflag = FTW_D;
141			break;
142		case FTS_DNR:
143			fnflag = FTW_DNR;
144			break;
145		case FTS_DP:
146			if (!postorder)
147				continue;
148			SKIP_MOUNT;
149			fnflag = FTW_DP;
150			break;
151		case FTS_F:
152		case FTS_DEFAULT:
153			fnflag = FTW_F;
154			break;
155		case FTS_NS:
156		case FTS_NSOK:
157			fnflag = FTW_NS;
158			break;
159		case FTS_SL:
160			fnflag = FTW_SL;
161			break;
162		case FTS_SLNONE:
163			fnflag = nfn ? FTW_SLN : FTW_SL;
164#if __DARWIN_UNIX03
165			{
166			    /* The legacy behaviour did not signal an error
167			      on symlink loops unless they ended up causing
168			      a directory cycle, but the Unix2003 standard
169			      requires ELOOP to end ftw and nftw walks with
170			      an error */
171			    struct stat sb;
172			    int rc = stat(cur->fts_path, &sb);
173			    if (rc < 0 && errno == ELOOP) {
174				error = -1;
175				goto done;
176			    }
177			}
178#endif
179			break;
180		case FTS_DC:
181#if __DARWIN_UNIX03
182			/* Unix03 says nftw should break cycles and not return
183			  errors in non-physical mode (which is definitly what it
184			  says ftw can't do) */
185			if (nfn && !(ftwflags & FTW_PHYS)) {
186				/* 4489297 - when FTW_DEPTH is set, skip
187				   the link also */
188				if (postorder)
189				    continue;
190				fnflag = FTW_D;
191				break;
192			}
193#endif
194			errno = ELOOP;
195			/* FALLTHROUGH */
196		default:
197			error = -1;
198			goto done;
199		}
200
201		if (cwd_fd >= 0) {
202		    char *dir, *free_me = NULL;
203		    if (fnflag == FTW_D) {
204			dir = cur->fts_path;
205		    } else {
206			/* we could alloc just enough for the directory,
207			  and use memmove -- but that is a little more
208			  error prone, and not noticable in with all the
209			  extra work... */
210			dir = free_me = strdup(cur->fts_path);
211			dir[cur->fts_pathlen - cur->fts_namelen] = '\0';
212		    }
213		    int rc = chdir(dir);
214		    if (free_me) {
215			free(free_me);
216		    }
217		    if (rc < 0) {
218			if(cur->fts_pathlen == cur->fts_namelen &&
219			   fnflag == FTW_DNR) {
220			    /* If cwd_fd is our last FD, fts_read will give us FTS_DNR
221			     * and fts_path == fts_name == "."
222			     * This check results in the correct errno being returned.
223			     */
224			    errno = EMFILE;
225			}
226			error = -1;
227			goto done;
228		    }
229		}
230		if (nfn) {
231		    ftw.base = cur->fts_pathlen - cur->fts_namelen;
232		    ftw.level = cur->fts_level;
233		    error = nfn(cur->fts_path, cur->fts_statp, fnflag, &ftw);
234		} else {
235		    error = ofn(cur->fts_path, cur->fts_statp, fnflag);
236		}
237		if (cwd_fd >= 0) {
238		    if (fchdir(cwd_fd) < 0) {
239			error = -1;
240			goto done;
241		    }
242		}
243
244		if (error != 0)
245			break;
246	}
247done:
248	sverrno = errno;
249	if(ftsp != NULL)
250		(void) fts_close(ftsp);
251	if(cwd_fd >= 0)
252		(void) close(cwd_fd);
253	errno = sverrno;
254	return (error);
255}
256
257int
258ftw(const char *path, int (*fn)(const char *, const struct stat *, int),
259    int nfds)
260{
261	/* The legacy implmentation didn't follow symlinks, but Unix03
262	  does - this was likely a bug in the legacy implemtation; JKH
263	  thinks we ought change the legacy behaviour, and I agree; anyone
264	  who doesn't should replace FTW_PHYS with
265	  __DARWIN_UNIX03 ? 0 : FTW_PHYS */
266	return both_ftw(path, fn, NULL, nfds, FTW_PHYS);
267}
268
269int
270nftw(const char *path, int (*fn)(const char *, const struct stat *, int,
271     struct FTW *), int nfds, int ftwflags)
272{
273	return both_ftw(path, NULL, fn, nfds, ftwflags);
274}
275