nftw.c raw

   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  
  11  struct 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  
  23  static 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  		DIR *d = fdopendir(dfd);
  88  		if (d) {
  89  			struct dirent *de;
  90  			while ((de = readdir(d))) {
  91  				if (de->d_name[0] == '.'
  92  				 && (!de->d_name[1]
  93  				  || (de->d_name[1]=='.'
  94  				   && !de->d_name[2]))) continue;
  95  				if (strlen(de->d_name) >= PATH_MAX-l) {
  96  					errno = ENAMETOOLONG;
  97  					closedir(d);
  98  					return -1;
  99  				}
 100  				path[j]='/';
 101  				strcpy(path+j+1, de->d_name);
 102  				if ((r=do_nftw(path, fn, fd_limit-1, flags, &new))) {
 103  					closedir(d);
 104  					return r;
 105  				}
 106  			}
 107  			closedir(d);
 108  		} else {
 109  			close(dfd);
 110  			return -1;
 111  		}
 112  	}
 113  
 114  	path[l] = 0;
 115  	if ((flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
 116  		return r;
 117  
 118  	return 0;
 119  }
 120  
 121  int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, struct FTW *), int fd_limit, int flags)
 122  {
 123  	int r, cs;
 124  	size_t l;
 125  	char pathbuf[PATH_MAX+1];
 126  
 127  	if (fd_limit <= 0) return 0;
 128  
 129  	l = strlen(path);
 130  	if (l > PATH_MAX) {
 131  		errno = ENAMETOOLONG;
 132  		return -1;
 133  	}
 134  	memcpy(pathbuf, path, l+1);
 135  	
 136  	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 137  	r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
 138  	pthread_setcancelstate(cs, 0);
 139  	return r;
 140  }
 141  
 142  weak_alias(nftw, nftw64);
 143