github.com/afumu/libc@v0.0.6/musl/src/misc/nftw.c (about)

     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);