src/misc/nftw.c

   1 #include <ftw.h>
   2 #include <dirent.h>
   3 #include <sys/stat.h>
   4 #include <errno.h>
   5 #include <unistd.h>
   6 #include <string.h>
   7 #include <limits.h>
   8 #include <pthread.h>
   9 #include "libc.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         struct FTW lev;
  31         char *name;
  32
  33         if ((flags & FTW_PHYS) ? lstat(path, &st) : stat(path, &st) < 0) {
  34                 if (!(flags & FTW_PHYS) && errno==ENOENT && !lstat(path, &st))
  35                         type = FTW_SLN;
  36                 else if (errno != EACCES) return -1;
  37                 else type = FTW_NS;
  38         } else if (S_ISDIR(st.st_mode)) {
  39                 if (access(path, R_OK) < 0) type = FTW_DNR;
  40                 else 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 = l+1;
  57
  58         lev.level = new.level;
  59         lev.base = h ? h->base : (name=strrchr(path, '/')) ? name-path : 0;
  60
  61         if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
  62                 return r;
  63
  64         for (; h; h = h->chain)
  65                 if (h->dev == st.st_dev && h->ino == st.st_ino)
  66                         return 0;
  67
  68         if ((type == FTW_D || type == FTW_DP) && fd_limit) {
  69                 DIR *d = opendir(path);
  70                 if (d) {
  71                         struct dirent *de;
  72                         while ((de = readdir(d))) {
  73                                 if (de->d_name[0] == '.'
  74                                  && (!de->d_name[1]
  75                                   || (de->d_name[1]=='.'
  76                                    && !de->d_name[2]))) continue;
  77                                 if (strlen(de->d_name) >= PATH_MAX-l) {
  78                                         errno = ENAMETOOLONG;
  79                                         closedir(d);
  80                                         return -1;
  81                                 }
  82                                 path[j]='/';
  83                                 strcpy(path+j+1, de->d_name);
  84                                 if ((r=do_nftw(path, fn, fd_limit-1, flags, &new))) {
  85                                         closedir(d);
  86                                         return r;
  87                                 }
  88                         }
  89                         closedir(d);
  90                 } else if (errno != EACCES) {
  91                         return -1;
  92                 }
  93         }
  94
  95         path[l] = 0;
  96         if ((flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
  97                 return r;
  98
  99         return 0;
 100 }
 101
 102 int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, struct FTW *), int fd_limit, int flags)
 103 {
 104         int r, cs;
 105         size_t l;
 106         char pathbuf[PATH_MAX+1];
 107
 108         if (fd_limit <= 0) return 0;
 109
 110         l = strlen(path);
 111         if (l > PATH_MAX) {
 112                 errno = ENAMETOOLONG;
 113                 return -1;
 114         }
 115         memcpy(pathbuf, path, l+1);
 116
 117         pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
 118         r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
 119         pthread_setcancelstate(cs, 0);
 120         return r;
 121 }
 122
 123 LFS64(nftw);