Add needed functions to glibc-compat for pkg

ports/glibc-compat/src/fts.c

+/*-
+ * Copyright (c) 1990, 1993, 1994
+ *  The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $OpenBSD: fts.c,v 1.22 1999/10/03 19:22:22 millert Exp $
+ */
+
+#if 0
+#if defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)fts.c  8.6 (Berkeley) 8/14/94";
+#endif /* LIBC_SCCS and not lint */
+#endif
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: release/10.1.0/lib/libc/gen/fts.c 264172 2014-04-05 \
+20:26:17Z jilles $");
+
+#include <sys/param.h>
+#include <sys/stat.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <fts.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/dirent.h>
+
+// Pull from freebsd 10.1 sys/mount.h
+/*
+ * NOTE: When changing statfs structure, mount structure, MNT_* flags or
+ * MNTK_* flags also update DDB show mount command in vfs_subr.c.
+ */
+
+typedef struct fsid { int32_t val[2]; } fsid_t; /* filesystem id type */
+
+/*
+ * filesystem statistics
+ */
+#define  MFSNAMELEN  16    /* length of type name including null */
+#define  MNAMELEN  88    /* size of on/from name bufs */
+#define  STATFS_VERSION  0x20030518  /* current version number */
+struct statfs {
+  uint32_t f_version;    /* structure version number */
+  uint32_t f_type;    /* type of filesystem */
+  uint64_t f_flags;    /* copy of mount exported flags */
+  uint64_t f_bsize;    /* filesystem fragment size */
+  uint64_t f_iosize;    /* optimal transfer block size */
+  uint64_t f_blocks;    /* total data blocks in filesystem */
+  uint64_t f_bfree;    /* free blocks in filesystem */
+  int64_t   f_bavail;    /* free blocks avail to non-superuser */
+  uint64_t f_files;    /* total file nodes in filesystem */
+  int64_t   f_ffree;    /* free nodes avail to non-superuser */
+  uint64_t f_syncwrites;    /* count of sync writes since mount */
+  uint64_t f_asyncwrites;    /* count of async writes since mount */
+  uint64_t f_syncreads;    /* count of sync reads since mount */
+  uint64_t f_asyncreads;    /* count of async reads since mount */
+  uint64_t f_spare[10];    /* unused spare */
+  uint32_t f_namemax;    /* maximum filename length */
+  uid_t    f_owner;    /* user that mounted the filesystem */
+  fsid_t    f_fsid;    /* filesystem id */
+  char    f_charspare[80];      /* spare string space */
+  char    f_fstypename[MFSNAMELEN]; /* filesystem type name */
+  char    f_mntfromname[MNAMELEN];  /* mounted filesystem */
+  char    f_mntonname[MNAMELEN];    /* directory on which mounted */
+};
+
+static FTSENT  *fts_alloc(FTS *, char *, size_t);
+static FTSENT  *fts_build(FTS *, int);
+static void   fts_lfree(FTSENT *);
+static void   fts_load(FTS *, FTSENT *);
+static size_t   fts_maxarglen(char * const *);
+static void   fts_padjust(FTS *, FTSENT *);
+static int   fts_palloc(FTS *, size_t);
+static FTSENT  *fts_sort(FTS *, FTSENT *, size_t);
+static int   fts_stat(FTS *, FTSENT *, int);
+static int   fts_safe_changedir(FTS *, FTSENT *, int, char *);
+static int   fts_ufslinks(FTS *, const FTSENT *);
+
+#define  ISDOT(a)  (a[0] == '.' && (!a[1] || (a[1] == '.' && !a[2])))
+
+#define  CLR(opt)  (sp->fts_options &= ~(opt))
+#define  ISSET(opt)  (sp->fts_options & (opt))
+#define  SET(opt)  (sp->fts_options |= (opt))
+
+#define  FCHDIR(sp, fd)  (!ISSET(FTS_NOCHDIR) && fchdir(fd))
+
+/* fts_build flags */
+#define  BCHILD    1    /* fts_children */
+#define  BNAMES    2    /* fts_children, names only */
+#define  BREAD    3    /* fts_read */
+
+/*
+ * Internal representation of an FTS, including extra implementation
+ * details.  The FTS returned from fts_open points to this structure's
+ * ftsp_fts member (and can be cast to an _fts_private as required)
+ */
+struct _fts_private {
+  FTS    ftsp_fts;
+  struct statfs  ftsp_statfs;
+  dev_t    ftsp_dev;
+  int    ftsp_linksreliable;
+};
+
+/*
+ * The "FTS_NOSTAT" option can avoid a lot of calls to stat(2) if it
+ * knows that a directory could not possibly have subdirectories.  This
+ * is decided by looking at the link count: a subdirectory would
+ * increment its parent's link count by virtue of its own ".." entry.
+ * This assumption only holds for UFS-like filesystems that implement
+ * links and directories this way, so we must punt for others.
+ */
+
+static const char *ufslike_filesystems[] = {
+  "ufs",
+  "zfs",
+  "nfs",
+  "nfs4",
+  "ext2fs",
+  0
+};
+
+FTS *
+fts_open(argv, options, compar)
+  char * const *argv;
+  int options;
+  int (*compar)(const FTSENT * const *, const FTSENT * const *);
+{
+  struct _fts_private *priv;
+  FTS *sp;
+  FTSENT *p, *root;
+  FTSENT *parent, *tmp;
+  size_t len, nitems;
+
+  /* Options check. */
+  if (options & ~FTS_OPTIONMASK) {
+    errno = EINVAL;
+    return (NULL);
+  }
+
+  /* fts_open() requires at least one path */
+  if (*argv == NULL) {
+    errno = EINVAL;
+    return (NULL);
+  }
+
+  /* Allocate/initialize the stream. */
+  if ((priv = calloc(1, sizeof(*priv))) == NULL)
+    return (NULL);
+  sp = &priv->ftsp_fts;
+  sp->fts_compar = compar;
+  sp->fts_options = options;
+
+  /* Shush, GCC. */
+  tmp = NULL;
+
+  /* Logical walks turn on NOCHDIR; symbolic links are too hard. */
+  if (ISSET(FTS_LOGICAL))
+    SET(FTS_NOCHDIR);
+
+  /*
+   * Start out with 1K of path space, and enough, in any case,
+   * to hold the user's paths.
+   */
+  if (fts_palloc(sp, MAX(fts_maxarglen(argv), MAXPATHLEN)))
+    goto mem1;
+
+  /* Allocate/initialize root's parent. */
+  if ((parent = fts_alloc(sp, "", 0)) == NULL)
+    goto mem2;
+  parent->fts_level = FTS_ROOTPARENTLEVEL;
+
+  /* Allocate/initialize root(s). */
+  for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
+    len = strlen(*argv);
+
+    p = fts_alloc(sp, *argv, len);
+    p->fts_level = FTS_ROOTLEVEL;
+    p->fts_parent = parent;
+    p->fts_accpath = p->fts_name;
+    p->fts_info = fts_stat(sp, p, ISSET(FTS_COMFOLLOW));
+
+    /* Command-line "." and ".." are real directories. */
+    if (p->fts_info == FTS_DOT)
+      p->fts_info = FTS_D;
+
+    /*
+     * If comparison routine supplied, traverse in sorted
+     * order; otherwise traverse in the order specified.
+     */
+    if (compar) {
+      p->fts_link = root;
+      root = p;
+    } else {
+      p->fts_link = NULL;
+      if (root == NULL)
+        tmp = root = p;
+      else {
+        tmp->fts_link = p;
+        tmp = p;
+      }
+    }
+  }
+  if (compar && nitems > 1)
+    root = fts_sort(sp, root, nitems);
+
+  /*
+   * Allocate a dummy pointer and make fts_read think that we've just
+   * finished the node before the root(s); set p->fts_info to FTS_INIT
+   * so that everything about the "current" node is ignored.
+   */
+  if ((sp->fts_cur = fts_alloc(sp, "", 0)) == NULL)
+    goto mem3;
+  sp->fts_cur->fts_link = root;
+  sp->fts_cur->fts_info = FTS_INIT;
+
+  /*
+   * If using chdir(2), grab a file descriptor pointing to dot to ensure
+   * that we can get back here; this could be avoided for some paths,
+   * but almost certainly not worth the effort.  Slashes, symbolic links,
+   * and ".." are all fairly nasty problems.  Note, if we can't get the
+   * descriptor we run anyway, just more slowly.
+   */
+  if (!ISSET(FTS_NOCHDIR) &&
+      (sp->fts_rfd = open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
+    SET(FTS_NOCHDIR);
+
+  return (sp);
+
+mem3:  fts_lfree(root);
+  free(parent);
+mem2:  free(sp->fts_path);
+mem1:  free(sp);
+  return (NULL);
+}
+
+static void
+fts_load(FTS *sp, FTSENT *p)
+{
+  size_t len;
+  char *cp;
+
+  /*
+   * Load the stream structure for the next traversal.  Since we don't
+   * actually enter the directory until after the preorder visit, set
+   * the fts_accpath field specially so the chdir gets done to the right
+   * place and the user can access the first node.  From fts_open it's
+   * known that the path will fit.
+   */
+  len = p->fts_pathlen = p->fts_namelen;
+  memmove(sp->fts_path, p->fts_name, len + 1);
+  if ((cp = strrchr(p->fts_name, '/')) && (cp != p->fts_name || cp[1])) {
+    len = strlen(++cp);
+    memmove(p->fts_name, cp, len + 1);
+    p->fts_namelen = len;
+  }
+  p->fts_accpath = p->fts_path = sp->fts_path;
+  sp->fts_dev = p->fts_dev;
+}
+
+int
+fts_close(FTS *sp)
+{
+  FTSENT *freep, *p;
+  int saved_errno;
+
+  /*
+   * This still works if we haven't read anything -- the dummy structure
+   * points to the root list, so we step through to the end of the root
+   * list which has a valid parent pointer.
+   */
+  if (sp->fts_cur) {
+    for (p = sp->fts_cur; p->fts_level >= FTS_ROOTLEVEL;) {
+      freep = p;
+      p = p->fts_link != NULL ? p->fts_link : p->fts_parent;
+      free(freep);
+    }
+    free(p);
+  }
+
+  /* Free up child linked list, sort array, path buffer. */
+  if (sp->fts_child)
+    fts_lfree(sp->fts_child);
+  if (sp->fts_array)
+    free(sp->fts_array);
+  free(sp->fts_path);
+
+  /* Return to original directory, save errno if necessary. */
+  if (!ISSET(FTS_NOCHDIR)) {
+    saved_errno = fchdir(sp->fts_rfd) ? errno : 0;
+    (void)close(sp->fts_rfd);
+
+    /* Set errno and return. */
+    if (saved_errno != 0) {
+      /* Free up the stream pointer. */
+      free(sp);
+      errno = saved_errno;
+      return (-1);
+    }
+  }
+
+  /* Free up the stream pointer. */
+  free(sp);
+  return (0);
+}
+
+/*
+ * Special case of "/" at the end of the path so that slashes aren't
+ * appended which would cause paths to be written as "....//foo".
+ */
+#define  NAPPEND(p)              \
+  (p->fts_path[p->fts_pathlen - 1] == '/'        \
+      ? p->fts_pathlen - 1 : p->fts_pathlen)
+
+FTSENT *
+fts_read(FTS *sp)
+{
+  FTSENT *p, *tmp;
+  int instr;
+  char *t;
+  int saved_errno;
+
+  /* If finished or unrecoverable error, return NULL. */
+  if (sp->fts_cur == NULL || ISSET(FTS_STOP))
+    return (NULL);
+
+  /* Set current node pointer. */
+  p = sp->fts_cur;
+
+  /* Save and zero out user instructions. */
+  instr = p->fts_instr;
+  p->fts_instr = FTS_NOINSTR;
+
+  /* Any type of file may be re-visited; re-stat and re-turn. */
+  if (instr == FTS_AGAIN) {
+    p->fts_info = fts_stat(sp, p, 0);
+    return (p);
+  }
+
+  /*
+   * Following a symlink -- SLNONE test allows application to see
+   * SLNONE and recover.  If indirecting through a symlink, have
+   * keep a pointer to current location.  If unable to get that
+   * pointer, follow fails.
+   */
+  if (instr == FTS_FOLLOW &&
+      (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
+    p->fts_info = fts_stat(sp, p, 1);
+    if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
+      if ((p->fts_symfd = open(".", O_RDONLY | O_CLOEXEC,
+          0)) < 0) {
+        p->fts_errno = errno;
+        p->fts_info = FTS_ERR;
+      } else
+        p->fts_flags |= FTS_SYMFOLLOW;
+    }
+    return (p);
+  }
+
+  /* Directory in pre-order. */
+  if (p->fts_info == FTS_D) {
+    /* If skipped or crossed mount point, do post-order visit. */
+    if (instr == FTS_SKIP ||
+        (ISSET(FTS_XDEV) && p->fts_dev != sp->fts_dev)) {
+      if (p->fts_flags & FTS_SYMFOLLOW)
+        (void)close(p->fts_symfd);
+      if (sp->fts_child) {
+        fts_lfree(sp->fts_child);
+        sp->fts_child = NULL;
+      }
+      p->fts_info = FTS_DP;
+      return (p);
+    }
+
+    /* Rebuild if only read the names and now traversing. */
+    if (sp->fts_child != NULL && ISSET(FTS_NAMEONLY)) {
+      CLR(FTS_NAMEONLY);
+      fts_lfree(sp->fts_child);
+      sp->fts_child = NULL;
+    }
+
+    /*
+     * Cd to the subdirectory.
+     *
+     * If have already read and now fail to chdir, whack the list
+     * to make the names come out right, and set the parent errno
+     * so the application will eventually get an error condition.
+     * Set the FTS_DONTCHDIR flag so that when we logically change
+     * directories back to the parent we don't do a chdir.
+     *
+     * If haven't read do so.  If the read fails, fts_build sets
+     * FTS_STOP or the fts_info field of the node.
+     */
+    if (sp->fts_child != NULL) {
+      if (fts_safe_changedir(sp, p, -1, p->fts_accpath)) {
+        p->fts_errno = errno;
+        p->fts_flags |= FTS_DONTCHDIR;
+        for (p = sp->fts_child; p != NULL;
+            p = p->fts_link)
+          p->fts_accpath =
+              p->fts_parent->fts_accpath;
+      }
+    } else if ((sp->fts_child = fts_build(sp, BREAD)) == NULL) {
+      if (ISSET(FTS_STOP))
+        return (NULL);
+      return (p);
+    }
+    p = sp->fts_child;
+    sp->fts_child = NULL;
+    goto name;
+  }
+
+  /* Move to the next node on this level. */
+next:  tmp = p;
+  if ((p = p->fts_link) != NULL) {
+    /*
+     * If reached the top, return to the original directory (or
+     * the root of the tree), and load the paths for the next root.
+     */
+    if (p->fts_level == FTS_ROOTLEVEL) {
+      if (FCHDIR(sp, sp->fts_rfd)) {
+        SET(FTS_STOP);
+        return (NULL);
+      }
+      free(tmp);
+      fts_load(sp, p);
+      return (sp->fts_cur = p);
+    }
+
+    /*
+     * User may have called fts_set on the node.  If skipped,
+     * ignore.  If followed, get a file descriptor so we can
+     * get back if necessary.
+     */
+    if (p->fts_instr == FTS_SKIP) {
+      free(tmp);
+      goto next;
+    }
+    if (p->fts_instr == FTS_FOLLOW) {
+      p->fts_info = fts_stat(sp, p, 1);
+      if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
+        if ((p->fts_symfd =
+            open(".", O_RDONLY | O_CLOEXEC, 0)) < 0) {
+          p->fts_errno = errno;
+          p->fts_info = FTS_ERR;
+        } else
+          p->fts_flags |= FTS_SYMFOLLOW;
+      }
+      p->fts_instr = FTS_NOINSTR;
+    }
+
+    free(tmp);
+
+name:    t = sp->fts_path + NAPPEND(p->fts_parent);
+    *t++ = '/';
+    memmove(t, p->fts_name, p->fts_namelen + 1);
+    return (sp->fts_cur = p);
+  }
+
+  /* Move up to the parent node. */
+  p = tmp->fts_parent;
+
+  if (p->fts_level == FTS_ROOTPARENTLEVEL) {
+    /*
+     * Done; free everything up and set errno to 0 so the user
+     * can distinguish between error and EOF.
+     */
+    free(tmp);
+    free(p);
+    errno = 0;
+    return (sp->fts_cur = NULL);
+  }
+
+  /* NUL terminate the pathname. */
+  sp->fts_path[p->fts_pathlen] = '\0';
+
+  /*
+   * Return to the parent directory.  If at a root node or came through
+   * a symlink, go back through the file descriptor.  Otherwise, cd up
+   * one directory.
+   */
+  if (p->fts_level == FTS_ROOTLEVEL) {
+    if (FCHDIR(sp, sp->fts_rfd)) {
+      SET(FTS_STOP);
+      return (NULL);
+    }
+  } else if (p->fts_flags & FTS_SYMFOLLOW) {
+    if (FCHDIR(sp, p->fts_symfd)) {
+      saved_errno = errno;
+      (void)close(p->fts_symfd);
+      errno = saved_errno;
+      SET(FTS_STOP);
+      return (NULL);
+    }
+    (void)close(p->fts_symfd);
+  } else if (!(p->fts_flags & FTS_DONTCHDIR) &&
+      fts_safe_changedir(sp, p->fts_parent, -1, "..")) {
+    SET(FTS_STOP);
+    return (NULL);
+  }
+  free(tmp);
+  p->fts_info = p->fts_errno ? FTS_ERR : FTS_DP;
+  return (sp->fts_cur = p);
+}
+
+/*
+ * Fts_set takes the stream as an argument although it's not used in this
+ * implementation; it would be necessary if anyone wanted to add global
+ * semantics to fts using fts_set.  An error return is allowed for similar
+ * reasons.
+ */
+/* ARGSUSED */
+int
+fts_set(FTS *sp, FTSENT *p, int instr)
+{
+  if (instr != 0 && instr != FTS_AGAIN && instr != FTS_FOLLOW &&
+      instr != FTS_NOINSTR && instr != FTS_SKIP) {
+    errno = EINVAL;
+    return (1);
+  }
+  p->fts_instr = instr;
+  return (0);
+}
+
+FTSENT *
+fts_children(FTS *sp, int instr)
+{
+  FTSENT *p;
+  int fd;
+
+  if (instr != 0 && instr != FTS_NAMEONLY) {
+    errno = EINVAL;
+    return (NULL);
+  }
+
+  /* Set current node pointer. */
+  p = sp->fts_cur;
+
+  /*
+   * Errno set to 0 so user can distinguish empty directory from
+   * an error.
+   */
+  errno = 0;
+
+  /* Fatal errors stop here. */
+  if (ISSET(FTS_STOP))
+    return (NULL);
+
+  /* Return logical hierarchy of user's arguments. */
+  if (p->fts_info == FTS_INIT)
+    return (p->fts_link);
+
+  /*
+   * If not a directory being visited in pre-order, stop here.  Could
+   * allow FTS_DNR, assuming the user has fixed the problem, but the
+   * same effect is available with FTS_AGAIN.
+   */
+  if (p->fts_info != FTS_D /* && p->fts_info != FTS_DNR */)
+    return (NULL);
+
+  /* Free up any previous child list. */
+  if (sp->fts_child != NULL)
+    fts_lfree(sp->fts_child);
+
+  if (instr == FTS_NAMEONLY) {
+    SET(FTS_NAMEONLY);
+    instr = BNAMES;
+  } else
+    instr = BCHILD;
+
+  /*
+   * If using chdir on a relative path and called BEFORE fts_read does
+   * its chdir to the root of a traversal, we can lose -- we need to
+   * chdir into the subdirectory, and we don't know where the current
+   * directory is, so we can't get back so that the upcoming chdir by
+   * fts_read will work.
+   */
+  if (p->fts_level != FTS_ROOTLEVEL || p->fts_accpath[0] == '/' ||
+      ISSET(FTS_NOCHDIR))
+    return (sp->fts_child = fts_build(sp, instr));
+
+  if ((fd = open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
+    return (NULL);
+  sp->fts_child = fts_build(sp, instr);
+  if (fchdir(fd)) {
+    (void)close(fd);
+    return (NULL);
+  }
+  (void)close(fd);
+  return (sp->fts_child);
+}
+
+#ifndef fts_get_clientptr
+#error "fts_get_clientptr not defined"
+#endif
+
+void *
+(fts_get_clientptr)(FTS *sp)
+{
+
+  return (fts_get_clientptr(sp));
+}
+
+#ifndef fts_get_stream
+#error "fts_get_stream not defined"
+#endif
+
+FTS *
+(fts_get_stream)(FTSENT *p)
+{
+  return (fts_get_stream(p));
+}
+
+void
+fts_set_clientptr(FTS *sp, void *clientptr)
+{
+
+  sp->fts_clientptr = clientptr;
+}
+
+/*
+ * This is the tricky part -- do not casually change *anything* in here.  The
+ * idea is to build the linked list of entries that are used by fts_children
+ * and fts_read.  There are lots of special cases.
+ *
+ * The real slowdown in walking the tree is the stat calls.  If FTS_NOSTAT is
+ * set and it's a physical walk (so that symbolic links can't be directories),
+ * we can do things quickly.  First, if it's a 4.4BSD file system, the type
+ * of the file is in the directory entry.  Otherwise, we assume that the number
+ * of subdirectories in a node is equal to the number of links to the parent.
+ * The former skips all stat calls.  The latter skips stat calls in any leaf
+ * directories and for any files after the subdirectories in the directory have
+ * been found, cutting the stat calls by about 2/3.
+ */
+static FTSENT *
+fts_build(FTS *sp, int type)
+{
+  struct dirent *dp;
+  FTSENT *p, *head;
+  FTSENT *cur, *tail;
+  DIR *dirp;
+  void *oldaddr;
+  char *cp;
+  int cderrno, descend, oflag, saved_errno, nostat, doadjust;
+  long level;
+  long nlinks;  /* has to be signed because -1 is a magic value */
+  size_t dnamlen, len, maxlen, nitems;
+
+  /* Set current node pointer. */
+  cur = sp->fts_cur;
+
+  /*
+   * Open the directory for reading.  If this fails, we're done.
+   * If being called from fts_read, set the fts_info field.
+   */
+#if defined FTS_WHITEOUT && !defined (__native_client__)
+  if (ISSET(FTS_WHITEOUT))
+    oflag = DTF_NODUP | DTF_REWIND;
+  else
+    oflag = DTF_HIDEW | DTF_NODUP | DTF_REWIND;
+#else
+#define __opendir2(path, flag) opendir(path)
+#endif
+  if ((dirp = __opendir2(cur->fts_accpath, oflag)) == NULL) {
+    if (type == BREAD) {
+      cur->fts_info = FTS_DNR;
+      cur->fts_errno = errno;
+    }
+    return (NULL);
+  }
+
+  /*
+   * Nlinks is the number of possible entries of type directory in the
+   * directory if we're cheating on stat calls, 0 if we're not doing
+   * any stat calls at all, -1 if we're doing stats on everything.
+   */
+  if (type == BNAMES) {
+    nlinks = 0;
+    /* Be quiet about nostat, GCC. */
+    nostat = 0;
+  } else if (ISSET(FTS_NOSTAT) && ISSET(FTS_PHYSICAL)) {
+#ifdef __native_client__
+    nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
+#else
+    if (fts_ufslinks(sp, cur))
+      nlinks = cur->fts_nlink - (ISSET(FTS_SEEDOT) ? 0 : 2);
+    else
+      nlinks = -1;
+#endif
+    nostat = 1;
+  } else {
+    nlinks = -1;
+    nostat = 0;
+  }
+
+#ifdef notdef
+  (void)printf("nlinks == %d (cur: %d)\n", nlinks, cur->fts_nlink);
+  (void)printf("NOSTAT %d PHYSICAL %d SEEDOT %d\n",
+      ISSET(FTS_NOSTAT), ISSET(FTS_PHYSICAL), ISSET(FTS_SEEDOT));
+#endif
+  /*
+   * If we're going to need to stat anything or we want to descend
+   * and stay in the directory, chdir.  If this fails we keep going,
+   * but set a flag so we don't chdir after the post-order visit.
+   * We won't be able to stat anything, but we can still return the
+   * names themselves.  Note, that since fts_read won't be able to
+   * chdir into the directory, it will have to return different path
+   * names than before, i.e. "a/b" instead of "b".  Since the node
+   * has already been visited in pre-order, have to wait until the
+   * post-order visit to return the error.  There is a special case
+   * here, if there was nothing to stat then it's not an error to
+   * not be able to stat.  This is all fairly nasty.  If a program
+   * needed sorted entries or stat information, they had better be
+   * checking FTS_NS on the returned nodes.
+   */
+  cderrno = 0;
+  if (nlinks || type == BREAD) {
+    if (fts_safe_changedir(sp, cur, dirfd(dirp), NULL)) {
+      if (nlinks && type == BREAD)
+        cur->fts_errno = errno;
+      cur->fts_flags |= FTS_DONTCHDIR;
+      descend = 0;
+      cderrno = errno;
+    } else
+      descend = 1;
+  } else
+    descend = 0;
+
+  /*
+   * Figure out the max file name length that can be stored in the
+   * current path -- the inner loop allocates more path as necessary.
+   * We really wouldn't have to do the maxlen calculations here, we
+   * could do them in fts_read before returning the path, but it's a
+   * lot easier here since the length is part of the dirent structure.
+   *
+   * If not changing directories set a pointer so that can just append
+   * each new name into the path.
+   */
+  len = NAPPEND(cur);
+  if (ISSET(FTS_NOCHDIR)) {
+    cp = sp->fts_path + len;
+    *cp++ = '/';
+  } else {
+    /* GCC, you're too verbose. */
+    cp = NULL;
+  }
+  len++;
+  maxlen = sp->fts_pathlen - len;
+
+  level = cur->fts_level + 1;
+
+  /* Read the directory, attaching each entry to the `link' pointer. */
+  doadjust = 0;
+  for (head = tail = NULL, nitems = 0; dirp && (dp = readdir(dirp));) {
+    dnamlen = strlen(dp->d_name);
+    if (!ISSET(FTS_SEEDOT) && ISDOT(dp->d_name))
+      continue;
+
+    if ((p = fts_alloc(sp, dp->d_name, dnamlen)) == NULL)
+      goto mem1;
+    if (dnamlen >= maxlen) {  /* include space for NUL */
+      oldaddr = sp->fts_path;
+      if (fts_palloc(sp, dnamlen + len + 1)) {
+        /*
+         * No more memory for path or structures.  Save
+         * errno, free up the current structure and the
+         * structures already allocated.
+         */
+mem1:        saved_errno = errno;
+        if (p)
+          free(p);
+        fts_lfree(head);
+        (void)closedir(dirp);
+        cur->fts_info = FTS_ERR;
+        SET(FTS_STOP);
+        errno = saved_errno;
+        return (NULL);
+      }
+      /* Did realloc() change the pointer? */
+      if (oldaddr != sp->fts_path) {
+        doadjust = 1;
+        if (ISSET(FTS_NOCHDIR))
+          cp = sp->fts_path + len;
+      }
+      maxlen = sp->fts_pathlen - len;
+    }
+
+    p->fts_level = level;
+    p->fts_parent = sp->fts_cur;
+    p->fts_pathlen = len + dnamlen;
+
+#if defined (FTS_WHITEOUT) && !(defined __native_client__)
+    if (dp->d_type == DT_WHT)
+      p->fts_flags |= FTS_ISW;
+#endif
+
+    if (cderrno) {
+      if (nlinks) {
+        p->fts_info = FTS_NS;
+        p->fts_errno = cderrno;
+      } else
+        p->fts_info = FTS_NSOK;
+      p->fts_accpath = cur->fts_accpath;
+    } else if (nlinks == 0
+#ifdef DT_DIR
+        || (nostat &&
+        dp->d_type != DT_DIR && dp->d_type != DT_UNKNOWN)
+#endif
+        ) {
+      p->fts_accpath =
+          ISSET(FTS_NOCHDIR) ? p->fts_path : p->fts_name;
+      p->fts_info = FTS_NSOK;
+    } else {
+      /* Build a file name for fts_stat to stat. */
+      if (ISSET(FTS_NOCHDIR)) {
+        p->fts_accpath = p->fts_path;
+        memmove(cp, p->fts_name, p->fts_namelen + 1);
+      } else
+        p->fts_accpath = p->fts_name;
+      /* Stat it. */
+      p->fts_info = fts_stat(sp, p, 0);
+
+      /* Decrement link count if applicable. */
+      if (nlinks > 0 && (p->fts_info == FTS_D ||
+          p->fts_info == FTS_DC || p->fts_info == FTS_DOT))
+        --nlinks;
+    }
+
+    /* We walk in directory order so "ls -f" doesn't get upset. */
+    p->fts_link = NULL;
+    if (head == NULL)
+      head = tail = p;
+    else {
+      tail->fts_link = p;
+      tail = p;
+    }
+    ++nitems;
+  }
+  if (dirp)
+    (void)closedir(dirp);
+
+  /*
+   * If realloc() changed the address of the path, adjust the
+   * addresses for the rest of the tree and the dir list.
+   */
+  if (doadjust)
+    fts_padjust(sp, head);
+
+  /*
+   * If not changing directories, reset the path back to original
+   * state.
+   */
+  if (ISSET(FTS_NOCHDIR))
+    sp->fts_path[cur->fts_pathlen] = '\0';
+
+  /*
+   * If descended after called from fts_children or after called from
+   * fts_read and nothing found, get back.  At the root level we use
+   * the saved fd; if one of fts_open()'s arguments is a relative path
+   * to an empty directory, we wind up here with no other way back.  If
+   * can't get back, we're done.
+   */
+  if (descend && (type == BCHILD || !nitems) &&
+      (cur->fts_level == FTS_ROOTLEVEL ?
+      FCHDIR(sp, sp->fts_rfd) :
+      fts_safe_changedir(sp, cur->fts_parent, -1, ".."))) {
+    cur->fts_info = FTS_ERR;
+    SET(FTS_STOP);
+    return (NULL);
+  }
+
+  /* If didn't find anything, return NULL. */
+  if (!nitems) {
+    if (type == BREAD)
+      cur->fts_info = FTS_DP;
+    return (NULL);
+  }
+
+  /* Sort the entries. */
+  if (sp->fts_compar && nitems > 1)
+    head = fts_sort(sp, head, nitems);
+  return (head);
+}
+
+static int
+fts_stat(FTS *sp, FTSENT *p, int follow)
+{
+  FTSENT *t;
+  dev_t dev;
+  ino_t ino;
+  struct stat *sbp, sb;
+  int saved_errno;
+
+  /* If user needs stat info, stat buffer already allocated. */
+  sbp = ISSET(FTS_NOSTAT) ? &sb : p->fts_statp;
+
+#if defined (FTS_WHITEOUT) && !defined(__native_client__)
+  /* Check for whiteout. */
+  if (p->fts_flags & FTS_ISW) {
+    if (sbp != &sb) {
+      memset(sbp, '\0', sizeof(*sbp));
+      sbp->st_mode = S_IFWHT;
+    }
+    return (FTS_W);
+  }
+#endif
+
+  /*
+   * If doing a logical walk, or application requested FTS_FOLLOW, do
+   * a stat(2).  If that fails, check for a non-existent symlink.  If
+   * fail, set the errno from the stat call.
+   */
+  if (ISSET(FTS_LOGICAL) || follow) {
+    if (stat(p->fts_accpath, sbp)) {
+      saved_errno = errno;
+      if (!lstat(p->fts_accpath, sbp)) {
+        errno = 0;
+        return (FTS_SLNONE);
+      }
+      p->fts_errno = saved_errno;
+      goto err;
+    }
+  } else if (lstat(p->fts_accpath, sbp)) {
+    p->fts_errno = errno;
+err:    memset(sbp, 0, sizeof(struct stat));
+    return (FTS_NS);
+  }
+
+  if (S_ISDIR(sbp->st_mode)) {
+    /*
+     * Set the device/inode.  Used to find cycles and check for
+     * crossing mount points.  Also remember the link count, used
+     * in fts_build to limit the number of stat calls.  It is
+     * understood that these fields are only referenced if fts_info
+     * is set to FTS_D.
+     */
+    dev = p->fts_dev = sbp->st_dev;
+    ino = p->fts_ino = sbp->st_ino;
+    p->fts_nlink = sbp->st_nlink;
+
+    if (ISDOT(p->fts_name))
+      return (FTS_DOT);
+
+    /*
+     * Cycle detection is done by brute force when the directory
+     * is first encountered.  If the tree gets deep enough or the
+     * number of symbolic links to directories is high enough,
+     * something faster might be worthwhile.
+     */
+    for (t = p->fts_parent;
+        t->fts_level >= FTS_ROOTLEVEL; t = t->fts_parent)
+      if (ino == t->fts_ino && dev == t->fts_dev) {
+        p->fts_cycle = t;
+        return (FTS_DC);
+      }
+    return (FTS_D);
+  }
+  if (S_ISLNK(sbp->st_mode))
+    return (FTS_SL);
+  if (S_ISREG(sbp->st_mode))
+    return (FTS_F);
+  return (FTS_DEFAULT);
+}
+
+/*
+ * The comparison function takes pointers to pointers to FTSENT structures.
+ * Qsort wants a comparison function that takes pointers to void.
+ * (Both with appropriate levels of const-poisoning, of course!)
+ * Use a trampoline function to deal with the difference.
+ */
+static int
+fts_compar(const void *a, const void *b)
+{
+  FTS *parent;
+
+  parent = (*(const FTSENT * const *)a)->fts_fts;
+  return (*parent->fts_compar)(a, b);
+}
+
+static FTSENT *
+fts_sort(FTS *sp, FTSENT *head, size_t nitems)
+{
+  FTSENT **ap, *p;
+
+  /*
+   * Construct an array of pointers to the structures and call qsort(3).
+   * Reassemble the array in the order returned by qsort.  If unable to
+   * sort for memory reasons, return the directory entries in their
+   * current order.  Allocate enough space for the current needs plus
+   * 40 so don't realloc one entry at a time.
+   */
+  if (nitems > sp->fts_nitems) {
+    sp->fts_nitems = nitems + 40;
+    if ((sp->fts_array = reallocf(sp->fts_array,
+        sp->fts_nitems * sizeof(FTSENT *))) == NULL) {
+      sp->fts_nitems = 0;
+      return (head);
+    }
+  }
+  for (ap = sp->fts_array, p = head; p; p = p->fts_link)
+    *ap++ = p;
+  qsort(sp->fts_array, nitems, sizeof(FTSENT *), fts_compar);
+  for (head = *(ap = sp->fts_array); --nitems; ++ap)
+    ap[0]->fts_link = ap[1];
+  ap[0]->fts_link = NULL;
+  return (head);
+}
+
+static FTSENT *
+fts_alloc(FTS *sp, char *name, size_t namelen)
+{
+  FTSENT *p;
+  size_t len;
+
+  struct ftsent_withstat {
+    FTSENT  ent;
+    struct  stat statbuf;
+  };
+
+  /*
+   * The file name is a variable length array and no stat structure is
+   * necessary if the user has set the nostat bit.  Allocate the FTSENT
+   * structure, the file name and the stat structure in one chunk, but
+   * be careful that the stat structure is reasonably aligned.
+   */
+  if (ISSET(FTS_NOSTAT))
+    len = sizeof(FTSENT) + namelen + 1;
+  else
+    len = sizeof(struct ftsent_withstat) + namelen + 1;
+
+  if ((p = malloc(len)) == NULL)
+    return (NULL);
+
+  if (ISSET(FTS_NOSTAT)) {
+    p->fts_name = (char *)(p + 1);
+    p->fts_statp = NULL;
+  } else {
+    p->fts_name = (char *)((struct ftsent_withstat *)p + 1);
+    p->fts_statp = &((struct ftsent_withstat *)p)->statbuf;
+  }
+
+  /* Copy the name and guarantee NUL termination. */
+  memcpy(p->fts_name, name, namelen);
+  p->fts_name[namelen] = '\0';
+  p->fts_namelen = namelen;
+  p->fts_path = sp->fts_path;
+  p->fts_errno = 0;
+  p->fts_flags = 0;
+  p->fts_instr = FTS_NOINSTR;
+  p->fts_number = 0;
+  p->fts_pointer = NULL;
+  p->fts_fts = sp;
+  return (p);
+}
+
+static void
+fts_lfree(FTSENT *head)
+{
+  FTSENT *p;
+
+  /* Free a linked list of structures. */
+  while ((p = head)) {
+    head = head->fts_link;
+    free(p);
+  }
+}
+
+/*
+ * Allow essentially unlimited paths; find, rm, ls should all work on any tree.
+ * Most systems will allow creation of paths much longer than MAXPATHLEN, even
+ * though the kernel won't resolve them.  Add the size (not just what's needed)
+ * plus 256 bytes so don't realloc the path 2 bytes at a time.
+ */
+static int
+fts_palloc(FTS *sp, size_t more)
+{
+
+  sp->fts_pathlen += more + 256;
+  sp->fts_path = reallocf(sp->fts_path, sp->fts_pathlen);
+  return (sp->fts_path == NULL);
+}
+
+/*
+ * When the path is realloc'd, have to fix all of the pointers in structures
+ * already returned.
+ */
+static void
+fts_padjust(FTS *sp, FTSENT *head)
+{
+  FTSENT *p;
+  char *addr = sp->fts_path;
+
+#define  ADJUST(p) do {              \
+  if ((p)->fts_accpath != (p)->fts_name) {      \
+    (p)->fts_accpath =          \
+        (char *)addr + ((p)->fts_accpath - (p)->fts_path);  \
+  }                \
+  (p)->fts_path = addr;            \
+} while (0)
+  /* Adjust the current set of children. */
+  for (p = sp->fts_child; p; p = p->fts_link)
+    ADJUST(p);
+
+  /* Adjust the rest of the tree, including the current level. */
+  for (p = head; p->fts_level >= FTS_ROOTLEVEL;) {
+    ADJUST(p);
+    p = p->fts_link ? p->fts_link : p->fts_parent;
+  }
+}
+
+static size_t
+fts_maxarglen(argv)
+  char * const *argv;
+{
+  size_t len, max;
+
+  for (max = 0; *argv; ++argv)
+    if ((len = strlen(*argv)) > max)
+      max = len;
+  return (max + 1);
+}
+
+/*
+ * Change to dir specified by fd or p->fts_accpath without getting
+ * tricked by someone changing the world out from underneath us.
+ * Assumes p->fts_dev and p->fts_ino are filled in.
+ */
+static int
+fts_safe_changedir(FTS *sp, FTSENT *p, int fd, char *path)
+{
+  int ret, oerrno, newfd;
+  struct stat sb;
+
+  newfd = fd;
+  if (ISSET(FTS_NOCHDIR))
+    return (0);
+  if (fd < 0 && (newfd = open(path, O_RDONLY | O_DIRECTORY |
+      O_CLOEXEC, 0)) < 0)
+    return (-1);
+  if (fstat(newfd, &sb)) {
+    ret = -1;
+    goto bail;
+  }
+  if (p->fts_dev != sb.st_dev || p->fts_ino != sb.st_ino) {
+    errno = ENOENT;    /* disinformation */
+    ret = -1;
+    goto bail;
+  }
+  ret = fchdir(newfd);
+bail:
+  oerrno = errno;
+  if (fd < 0)
+    (void)close(newfd);
+  errno = oerrno;
+  return (ret);
+}
+
+// native client does not implement statfs
+#ifndef __native_client__
+/*
+ * Check if the filesystem for "ent" has UFS-style links.
+ */
+static int
+fts_ufslinks(FTS *sp, const FTSENT *ent)
+{
+  struct _fts_private *priv;
+  const char **cpp;
+
+  priv = (struct _fts_private *)sp;
+  /*
+   * If this node's device is different from the previous, grab
+   * the filesystem information, and decide on the reliability
+   * of the link information from this filesystem for stat(2)
+   * avoidance.
+   */
+  if (priv->ftsp_dev != ent->fts_dev) {
+    if (statfs(ent->fts_path, &priv->ftsp_statfs) != -1) {
+      priv->ftsp_dev = ent->fts_dev;
+      priv->ftsp_linksreliable = 0;
+      for (cpp = ufslike_filesystems; *cpp; cpp++) {
+        if (strcmp(priv->ftsp_statfs.f_fstypename,
+            *cpp) == 0) {
+          priv->ftsp_linksreliable = 1;
+          break;
+        }
+      }
+    } else {
+      priv->ftsp_linksreliable = 0;
+    }
+  }
+  return (priv->ftsp_linksreliable);
+}
+#endif