1#include <ftw.h>
2#include <dirent.h>
3#include <fcntl.h>
4#include <sys/stat.h>
5#include <errno.h>
6#include <unistd.h>
7#include <string.h>
8#include <limits.h>
9#include <pthread.h>
10
11struct history
12{
13	struct history *chain;
14	dev_t dev;
15	ino_t ino;
16	int level;
17	int base;
18};
19
20#undef dirfd
21#define dirfd(d) (*(int *)d)
22
23static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int, struct FTW *), int fd_limit, int flags, struct history *h)
24{
25	size_t l = strlen(path), j = l && path[l-1]=='/' ? l-1 : l;
26	struct stat st;
27	struct history new;
28	int type;
29	int r;
30	int dfd;
31	int err;
32	struct FTW lev;
33
34	if ((flags & FTW_PHYS) ? lstat(path, &st) : stat(path, &st) < 0) {
35		if (!(flags & FTW_PHYS) && errno==ENOENT && !lstat(path, &st))
36			type = FTW_SLN;
37		else if (errno != EACCES) return -1;
38		else type = FTW_NS;
39	} else if (S_ISDIR(st.st_mode)) {
40		if (flags & FTW_DEPTH) type = FTW_DP;
41		else type = FTW_D;
42	} else if (S_ISLNK(st.st_mode)) {
43		if (flags & FTW_PHYS) type = FTW_SL;
44		else type = FTW_SLN;
45	} else {
46		type = FTW_F;
47	}
48
49	if ((flags & FTW_MOUNT) && h && st.st_dev != h->dev)
50		return 0;
51
52	new.chain = h;
53	new.dev = st.st_dev;
54	new.ino = st.st_ino;
55	new.level = h ? h->level+1 : 0;
56	new.base = j+1;
57
58	lev.level = new.level;
59	if (h) {
60		lev.base = h->base;
61	} else {
62		size_t k;
63		for (k=j; k && path[k]=='/'; k--);
64		for (; k && path[k-1]!='/'; k--);
65		lev.base = k;
66	}
67
68	if (type == FTW_D || type == FTW_DP) {
69		dfd = open(path, O_RDONLY);
70		err = errno;
71		if (dfd < 0 && err == EACCES) type = FTW_DNR;
72		if (!fd_limit) close(dfd);
73	}
74
75	if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
76		return r;
77
78	for (; h; h = h->chain)
79		if (h->dev == st.st_dev && h->ino == st.st_ino)
80			return 0;
81
82	if ((type == FTW_D || type == FTW_DP) && fd_limit) {
83		if (dfd < 0) {
84			errno = err;
85			return -1;
86		}
87		{
88		DIR *d = fdopendir(dfd);
89		if (d) {
90			struct dirent *de;
91			while ((de = readdir(d))) {
92				if (de->d_name[0] == '.'
93				 && (!de->d_name[1]
94				  || (de->d_name[1]=='.'
95				   && !de->d_name[2]))) continue;
96				if (strlen(de->d_name) >= PATH_MAX-l) {
97					errno = ENAMETOOLONG;
98					closedir(d);
99					return -1;
100				}
101				path[j]='/';
102				strcpy(path+j+1, de->d_name);
103				if ((r=do_nftw(path, fn, fd_limit-1, flags, &new))) {
104					closedir(d);
105					return r;
106				}
107			}
108			closedir(d);
109		} else {
110			close(dfd);
111			return -1;
112		}
113		}
114	}
115
116	path[l] = 0;
117	if ((flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
118		return r;
119
120	return 0;
121}
122
123int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, struct FTW *), int fd_limit, int flags)
124{
125	int r, cs;
126	size_t l;
127	char pathbuf[PATH_MAX+1];
128
129	if (fd_limit <= 0) return 0;
130
131	l = strlen(path);
132	if (l > PATH_MAX) {
133		errno = ENAMETOOLONG;
134		return -1;
135	}
136	memcpy(pathbuf, path, l+1);
137
138	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
139	r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
140	pthread_setcancelstate(cs, 0);
141	return r;
142}
143