src/misc/nftw.c

   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);