Update.cvs/libc-ud-970539cvs/libc-ud-970529

	* io/Makefile (test-srcs): Add ftwtest.
	(distribute): Add ftwtest-sh.
	(tests): Call ftwtest-sh for this goal.
	* io/ftwtest-sh: New file.  Sets up test environment, calls test
	program and compares the result.
	* io/ftwtest.c: Test program for ftw.

	* misc/search.h: Add comments.  Declare tdestroy.
	* misc/tsearch.c (tdestroy): New function.

9 files changed, 359 insertions, 59 deletions

diff --git a/.cvsignore b/.cvsignore
index 1378938..e724ae9 100644
--- a/.cvsignore
+++ b/.cvsignore
@@ -14,6 +14,7 @@ gpl2lgpl.sed
 distinfo
 distinfo
 
+test-include
 analysis
 docs
 
diff --git a/ChangeLog b/ChangeLog
index 5c3cf9d..199ee31 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,15 @@
 
 	* io/ftw.c: Complete rewrite.  Add implementation of `nftw'.
 	* io/ftw.h: Update for new implementation and XPG4.2.
+	* io/Makefile (test-srcs): Add ftwtest.
+	(distribute): Add ftwtest-sh.
+	(tests): Call ftwtest-sh for this goal.
+	* io/ftwtest-sh: New file.  Sets up test environment, calls test
+	program and compares the result.
+	* io/ftwtest.c: Test program for ftw.
+
+	* misc/search.h: Add comments.  Declare tdestroy.
+	* misc/tsearch.c (tdestroy): New function.
 
 	* login/Makefile: Update for UTMP daemon implementation.
 
diff --git a/io/Makefile b/io/Makefile
index f1efd21..d199f91 100644
--- a/io/Makefile
+++ b/io/Makefile
@@ -51,9 +51,15 @@ routines :=							      \
 static-only-routines = stat fstat lstat mknod
 
 others		:= pwd
+test-srcs	:= ftwtest
 tests		:= test-utime
 
+distribute	:= ftwtest-sh
+
 include ../Rules
 
 CFLAGS-fts.c = -Wno-uninitialized
 CFLAGS-ftw.c = -Wno-uninitialized
+
+tests: $(objpfx)ftwtest
+	$(SHELL) -e ftwtest-sh $(common-objpfx) $<
diff --git a/io/ftw.c b/io/ftw.c
index e20ad23..7367f97 100644
--- a/io/ftw.c
+++ b/io/ftw.c
@@ -38,24 +38,44 @@ struct dir_data
   char *content;
 };
 
+struct known_object
+{
+  dev_t dev;
+  ino_t ino;
+};
+
 struct ftw_data
 {
+  /* Array with pointers to open directory streams.  */
   struct dir_data **dirstreams;
   size_t actdir;
   size_t maxdir;
 
+  /* Buffer containing name of currently processed object.  */
   char *dirbuf;
   size_t dirbufsize;
+
+  /* Passed as fourth argument to `nftw' callback.  The `base' member
+     tracks the content of the `dirbuf'.  */
   struct FTW ftw;
 
+  /* Flags passed to `nftw' function.  0 for `ftw'.  */
   int flags;
 
+  /* Conversion array for flag values.  It is the identity mapping for
+     `nftw' calls, otherwise it maps the values to those know by
+     `ftw'.  */
   int *cvt_arr;
-  __nftw_func_t func;
 
-  struct stat st;
+  /* Callback function.  We always use the `nftw' form.  */
+  __nftw_func_t func;
 
+  /* Device of starting point.  Needed for FTW_MOUNT.  */
   dev_t dev;
+
+  /* Data structure for keeping fingerprints of already processed
+     object.  This is needed when not using FTW_PHYS.  */
+  void *known_objects;
 };
 
 
@@ -74,7 +94,36 @@ static int ftw_arr[] =
 
 
 /* Forward declarations of local functions.  */
-static int ftw_dir (struct ftw_data *data);
+static int ftw_dir (struct ftw_data *data, struct stat *st);
+
+
+static int
+object_compare (const void *p1, const void *p2)
+{
+  /* We don't need a sophisticated and useful comparison.  We are only
+     interested in equality.  */
+  return memcmp (p1, p2, sizeof (struct known_object));
+}
+
+
+static inline int
+add_object (struct ftw_data *data, struct stat *st)
+{
+  struct known_object *newp = malloc (sizeof (struct known_object));
+  if (newp == NULL)
+    return -1;
+  newp->dev = st->st_dev;
+  newp->ino = st->st_ino;
+  return __tsearch (newp, &data->known_objects, object_compare) ? 0 : -1;
+}
+
+
+static inline int
+find_object (struct ftw_data *data, struct stat *st)
+{
+  struct known_object obj = { dev: st->st_dev, ino: st->st_ino };
+  return __tfind (&obj, &data->known_objects, object_compare) != NULL;
+}
 
 
 static inline int
@@ -170,6 +219,7 @@ static inline int
 process_entry (struct ftw_data *data, struct dir_data *dir, const char *name,
 	       size_t namlen)
 {
+  struct stat st;
   int result = 0;
   int flag;
 
@@ -193,65 +243,72 @@ process_entry (struct ftw_data *data, struct dir_data *dir, const char *name,
   memcpy (data->dirbuf + data->ftw.base, name, namlen);
   data->dirbuf[data->ftw.base + namlen] = '\0';
 
-  if (((data->flags & FTW_PHYS) ? lstat : stat) (data->dirbuf, &data->st) < 0)
+  if (((data->flags & FTW_PHYS) ? lstat : stat) (data->dirbuf, &st) < 0)
     {
       if (errno != EACCES && errno != ENOENT)
 	result = -1;
       else if (!(data->flags & FTW_PHYS)
-	       && lstat (data->dirbuf, &data->st) == 0
-	       && S_ISLNK (data->st.st_mode))
+	       && lstat (data->dirbuf, &st) == 0
+	       && S_ISLNK (st.st_mode))
 	flag = FTW_SLN;
       else
 	flag = FTW_NS;
     }
   else
     {
-      if (S_ISDIR (data->st.st_mode))
+      if (S_ISDIR (st.st_mode))
 	flag = FTW_D;
-      else if (S_ISLNK (data->st.st_mode))
+      else if (S_ISLNK (st.st_mode))
 	flag = FTW_SL;
       else
 	flag = FTW_F;
     }
 
   if (result == 0
-      && (!(data->flags & FTW_MOUNT) || data->st.st_dev == data->dev))
+      && (!(data->flags & FTW_MOUNT) || flag == FTW_NS
+	  || st.st_dev == data->dev))
     {
-      if (flag == FTW_D)
+      if ((data->flags & FTW_PHYS) || flag == FTW_NS
+	  || (!find_object (data, &st)
+	      /* Remember the object.  */
+	      && (result = add_object (data, &st)) == 0))
 	{
-	  result = ftw_dir (data);
-
-	  if (result == 0 && (data->flags & FTW_CHDIR))
+	  if (flag == FTW_D)
 	    {
-	      /* Change back to current directory.  */
-	      int done = 0;
-	      if (dir->stream != NULL)
-		if (fchdir (dirfd (dir->stream)) == 0)
-		  done = 1;
+	      result = ftw_dir (data, &st);
 
-	      if (!done)
+	      if (result == 0 && (data->flags & FTW_CHDIR))
 		{
-		  if (data->ftw.base == 1)
-		    {
-		      if (chdir ("/") < 0)
-			result = -1;
-		    }
-		  else
-		    {
-		      /* Please note that we overwrite a slash.  */
-		      data->dirbuf[data->ftw.base - 1] = '\0';
+		  /* Change back to current directory.  */
+		  int done = 0;
+		  if (dir->stream != NULL)
+		    if (fchdir (dirfd (dir->stream)) == 0)
+		      done = 1;
 
-		      if (chdir (data->dirbuf) < 0)
-			result = -1;
+		  if (!done)
+		    {
+		      if (data->ftw.base == 1)
+			{
+			  if (chdir ("/") < 0)
+			    result = -1;
+			}
 		      else
-			data->dirbuf[data->ftw.base - 1] = '/';
+			{
+			  /* Please note that we overwrite a slash.  */
+			  data->dirbuf[data->ftw.base - 1] = '\0';
+
+			  if (chdir (data->dirbuf) < 0)
+			    result = -1;
+
+			  data->dirbuf[data->ftw.base - 1] = '/';
+			}
 		    }
 		}
 	    }
+	  else
+	    result = (*data->func) (data->dirbuf, &st, data->cvt_arr[flag],
+				    &data->ftw);
 	}
-      else
-	result = (*data->func) (data->dirbuf, &data->st, data->cvt_arr[flag],
-				&data->ftw);
     }
 
   return result;
@@ -259,28 +316,34 @@ process_entry (struct ftw_data *data, struct dir_data *dir, const char *name,
 
 
 static int
-ftw_dir (struct ftw_data *data)
+ftw_dir (struct ftw_data *data, struct stat *st)
 {
   struct dir_data dir;
   struct dirent *d;
   int previous_base = data->ftw.base;
-  int result = 0;
+  int result;
   char *startp;
 
+  /* Open the stream for this directory.  This might require that
+     another stream has to be closed.  */
+  result = open_dir_stream (data, &dir);
+  if (result != 0)
+    {
+      if (errno == EACCES)
+	/* We cannot read the directory.  Signal this with a special flag.  */
+	result = (*data->func) (data->dirbuf, st, FTW_DNR, &data->ftw);
+
+      return result;
+    }
+
   /* First, report the directory (if not depth-first).  */
   if (!(data->flags & FTW_DEPTH))
     {
-      result = (*data->func) (data->dirbuf, &data->st, FTW_D, &data->ftw);
+      result = (*data->func) (data->dirbuf, st, FTW_D, &data->ftw);
       if (result != 0)
 	return result;
     }
 
-  /* Open the stream for this directory.  This might require that
-     another stream has to be closed.  */
-  result = open_dir_stream (data, &dir);
-  if (result != 0)
-    return result;
-
   /* If necessary, change to this directory.  */
   if (data->flags & FTW_CHDIR)
     {
@@ -361,12 +424,13 @@ ftw_dir (struct ftw_data *data)
     }
 
   /* Prepare the return, revert the `struct FTW' information.  */
+  data->dirbuf[data->ftw.base - 1] = '\0';
   --data->ftw.level;
   data->ftw.base = previous_base;
 
   /* Finally, if we process depth-first report the directory.  */
   if (result == 0 && (data->flags & FTW_DEPTH))
-    result = (*data->func) (data->dirbuf, &data->st, FTW_DP, &data->ftw);
+    result = (*data->func) (data->dirbuf, st, FTW_DP, &data->ftw);
 
   return result;
 }
@@ -377,9 +441,10 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
 	     int flags)
 {
   struct ftw_data data;
+  struct stat st;
   int result = 0;
   int save_err;
-  char *cwd;
+  char *cwd = NULL;
   char *cp;
 
   /* First make sure the parameters are reasonable.  */
@@ -399,7 +464,7 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
   data.dirbuf = (char *) malloc (data.dirbufsize);
   if (data.dirbuf == NULL)
     return -1;
-  cp = stpcpy (data.dirbuf, dir);
+  cp = __stpcpy (data.dirbuf, dir);
   /* Strip trailing slashes.  */
   while (cp > data.dirbuf + 1 && cp[-1] == '/')
     --cp;
@@ -426,6 +491,9 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
      to reduce the value range before calling a `ftw' callback.  */
   data.cvt_arr = is_nftw ? nftw_arr : ftw_arr;
 
+  /* No object known so far.  */
+  data.known_objects = NULL;
+
   /* Now go to the directory containing the initial file/directory.  */
   if ((flags & FTW_CHDIR) && data.ftw.base > 0)
     {
@@ -453,14 +521,14 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
 
   /* Get stat info for start directory.  */
   if (result == 0)
-    if (((flags & FTW_PHYS) ? lstat : stat) (data.dirbuf, &data.st) < 0)
+    if (((flags & FTW_PHYS) ? lstat : stat) (data.dirbuf, &st) < 0)
       {
 	if (errno == EACCES)
-	  result = (*data.func) (data.dirbuf, &data.st, FTW_NS, &data.ftw);
+	  result = (*data.func) (data.dirbuf, &st, FTW_NS, &data.ftw);
 	else if (!(flags & FTW_PHYS)
 		 && errno == ENOENT
-		 && lstat (dir, &data.st) == 0 && S_ISLNK (data.st.st_mode))
-	  result = (*data.func) (data.dirbuf, &data.st, data.cvt_arr[FTW_SLN],
+		 && lstat (dir, &st) == 0 && S_ISLNK (st.st_mode))
+	  result = (*data.func) (data.dirbuf, &st, data.cvt_arr[FTW_SLN],
 				 &data.ftw);
 	else
 	  /* No need to call the callback since we cannot say anything
@@ -469,16 +537,24 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
       }
     else
       {
-	if (S_ISDIR (data.st.st_mode))
+	if (S_ISDIR (st.st_mode))
 	  {
-	    data.dev = data.st.st_dev;
-	    result = ftw_dir (&data);
+	    /* Remember the device of the initial directory in case
+	       FTW_MOUNT is given.  */
+	    data.dev = st.st_dev;
+
+	    /* We know this directory now.  */
+	    if (!(flags & FTW_PHYS))
+	      result = add_object (&data, &st);
+
+	    if (result == 0)
+	      result = ftw_dir (&data, &st);
 	  }
 	else
 	  {
-	    int flag = S_ISLNK (data.st.st_mode) ? FTW_SL : FTW_F;
+	    int flag = S_ISLNK (st.st_mode) ? FTW_SL : FTW_F;
 
-	    result = (*data.func) (data.dirbuf, &data.st, data.cvt_arr[flag],
+	    result = (*data.func) (data.dirbuf, &st, data.cvt_arr[flag],
 				   &data.ftw);
 	  }
       }
@@ -494,6 +570,7 @@ ftw_startup (const char *dir, int is_nftw, void *func, int descriptors,
 
   /* Free all memory.  */
   save_err = errno;
+  __tdestroy (data.known_objects, free);
   free (data.dirbuf);
   __set_errno (save_err);
 
diff --git a/io/ftw.h b/io/ftw.h
index 70fb9e2..d283e69 100644
--- a/io/ftw.h
+++ b/io/ftw.h
@@ -44,11 +44,13 @@ enum
   FTW_NS,		/* Unstatable file.  */
 #define FTW_NS	 FTW_NS
 
-#ifdef __USE_XOPEN_EXTENDED
+#if defined __USE_BSD || defined __USE_XOPEN_EXTENDED
 
   FTW_SL,		/* Symbolic link.  */
 # define FTW_SL	 FTW_SL
+#endif
 
+#ifdef __USE_XOPEN_EXTENDED
 /* These flags are only passed from the `nftw' function.  */
   FTW_DP,		/* Directory, all subdirs have been visited. */
 # define FTW_DP	 FTW_DP
diff --git a/io/ftwtest-sh b/io/ftwtest-sh
new file mode 100644
index 0000000..1c7c398
--- /dev/null
+++ b/io/ftwtest-sh
@@ -0,0 +1,84 @@
+#! /bin/sh
+
+# The common objpfx, used to find libraries and the dynamic loader.
+objpfx=$1
+
+# We expect one parameter which is the test program.  This must understand
+# a number options:
+#   --phys	use the FTW_PHYS flag
+#   --chdir	use the FTW_CHDIR and print the current directory in the
+#		callback
+#   --depth	use the FTW_DEPTH flag
+testprogram=$2
+
+
+# First create our scenario:
+tmp=${TMPDIR:-/tmp}
+tmpdir=$tmp/ftwtest.d
+
+trap 'rm -fr $tmpdir $testout' 1 2 3 15
+
+if test -d $tmpdir; then
+  chmod -R a+x $tmpdir
+  rm -fr $tmpdir
+fi
+mkdir $tmpdir
+mkdir $tmpdir/foo
+mkdir $tmpdir/bar
+echo > $tmpdir/baz
+mkdir $tmpdir/foo/lvl1
+echo > $tmpdir/foo/lvl1/file@1
+mkdir $tmpdir/foo/lvl1/lvl2
+echo > $tmpdir/foo/lvl1/lvl2/file@2
+mkdir $tmpdir/foo/lvl1/lvl2/lvl3
+echo > $tmpdir/foo/lvl1/lvl2/lvl3/file@3
+ln -s $tmpdir $tmpdir/foo/lvl1/lvl2/lvl3/link@3
+ln -s $tmpdir/foo/lvl1/lvl2 $tmpdir/foo/lvl1/lvl2/link@2
+ln -s $tmpdir/foo/lvl1/lvl2/lvl3/lvl4 $tmpdir/foo/lvl1/link@1
+echo > $tmpdir/bar/xo
+chmod a-x,a+r $tmpdir/bar
+
+testout=${TMPDIR:-/tmp}/ftwtest.out
+LD_LIBRARY_PATH=$objpfx $objpfx/elf/ld.so $testprogram $tmpdir |
+    sort > $testout
+
+cat <<EOF | cmp $testout - || exit 1
+base = "$tmp/", file = "ftwtest.d", flag = FTW_D
+base = "$tmp/ftwtest.d/", file = "bar", flag = FTW_D
+base = "$tmp/ftwtest.d/", file = "baz", flag = FTW_F
+base = "$tmp/ftwtest.d/", file = "foo", flag = FTW_D
+base = "$tmp/ftwtest.d/bar/", file = "xo", flag = FTW_NS
+base = "$tmp/ftwtest.d/foo/", file = "lvl1", flag = FTW_D
+base = "$tmp/ftwtest.d/foo/lvl1/", file = "file@1", flag = FTW_F
+base = "$tmp/ftwtest.d/foo/lvl1/", file = "link@1", flag = FTW_SLN
+base = "$tmp/ftwtest.d/foo/lvl1/", file = "lvl2", flag = FTW_D
+base = "$tmp/ftwtest.d/foo/lvl1/lvl2/", file = "file@2", flag = FTW_F
+base = "$tmp/ftwtest.d/foo/lvl1/lvl2/", file = "lvl3", flag = FTW_D
+base = "$tmp/ftwtest.d/foo/lvl1/lvl2/lvl3/", file = "file@3", flag = FTW_F
+EOF
+rm $testout
+
+testout=${TMPDIR:-/tmp}/ftwtest.out
+LD_LIBRARY_PATH=$objpfx $objpfx/elf/ld.so $testprogram --depth $tmpdir |
+    sort > $testout
+
+cat <<EOF | cmp $testout - || exit 1
+base = "/tmp/", file = "ftwtest.d", flag = FTW_DP
+base = "/tmp/ftwtest.d/", file = "bar", flag = FTW_DP
+base = "/tmp/ftwtest.d/", file = "baz", flag = FTW_F
+base = "/tmp/ftwtest.d/", file = "foo", flag = FTW_DP
+base = "/tmp/ftwtest.d/bar/", file = "xo", flag = FTW_NS
+base = "/tmp/ftwtest.d/foo/", file = "lvl1", flag = FTW_DP
+base = "/tmp/ftwtest.d/foo/lvl1/", file = "file@1", flag = FTW_F
+base = "/tmp/ftwtest.d/foo/lvl1/", file = "link@1", flag = FTW_SLN
+base = "/tmp/ftwtest.d/foo/lvl1/", file = "lvl2", flag = FTW_DP
+base = "/tmp/ftwtest.d/foo/lvl1/lvl2/", file = "file@2", flag = FTW_F
+base = "/tmp/ftwtest.d/foo/lvl1/lvl2/", file = "lvl3", flag = FTW_DP
+base = "/tmp/ftwtest.d/foo/lvl1/lvl2/lvl3/", file = "file@3", flag = FTW_F
+EOF
+rm $testout
+
+chmod -R a+x $tmpdir
+rm -fr $tmpdir
+
+exit 0
\ No newline at end of file
diff --git a/io/ftwtest.c b/io/ftwtest.c
new file mode 100644
index 0000000..6daa7e9
--- /dev/null
+++ b/io/ftwtest.c
@@ -0,0 +1,71 @@
+#include <ftw.h>
+#include <getopt.h>
+#include <mcheck.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+
+int do_depth;
+int do_chdir;
+int do_phys;
+
+struct option options[] =
+{
+  { "depth", no_argument, &do_depth, 1 },
+  { "chdir", no_argument, &do_chdir, 1 },
+  { "phys", no_argument, &do_phys, 1 },
+  { NULL, 0, NULL, 0 }
+};
+
+const char *flag2name[] =
+{
+  [FTW_F] = "FTW_F",
+  [FTW_D] = "FTW_D",
+  [FTW_DNR] = "FTW_DNR",
+  [FTW_NS] = "FTW_NS",
+  [FTW_SL] = "FTW_SL",
+  [FTW_DP] = "FTW_DP",
+  [FTW_SLN] = "FTW_SLN"
+};
+
+
+int
+cb (const char *name, const struct stat *st, int flag, struct FTW *f)
+{
+  printf ("base = \"%.*s\", file = \"%s\", flag = %s",
+	  f->base, name, name + f->base, flag2name[flag]);
+  if (do_chdir)
+    {
+      char *cwd = getcwd (NULL, 0);
+      printf (", cwd = %s", cwd);
+      free (cwd);
+    }
+  puts ("");
+  return 0;
+}
+
+int
+main (int argc, char *argv[])
+{
+  int opt;
+  int r;
+  int flag = 0;
+  mtrace ();
+
+  while ((opt = getopt_long_only (argc, argv, "", options, NULL)) != -1)
+    ;
+
+  if (do_chdir)
+    flag |= FTW_CHDIR;
+  if (do_depth)
+    flag |= FTW_DEPTH;
+  if (do_phys)
+    flag |= FTW_PHYS;
+
+  r = nftw (optind < argc ? argv[optind] : ".", cb, 3, flag);
+  if (r)
+    perror ("nftw");
+  return r;
+}
diff --git a/misc/search.h b/misc/search.h
index 8ce3351..ff0672d 100644
--- a/misc/search.h
+++ b/misc/search.h
@@ -106,16 +106,21 @@ typedef enum
 }
 VISIT;
 
+/* Search for an entry matching the given KEY in the tree pointed to
+   by *ROOTP and insert a new element if not found.  */
 extern void *tsearch __P ((__const void * __key, void **__rootp,
 			   __compar_fn_t compar));
 extern void *__tsearch __P ((__const void * __key, void **__rootp,
 			     __compar_fn_t compar));
 
-extern void *tfind __P ((__const void * __key, __const void ** __rootp,
+/* Search for an entry matching the given KEY in the tree pointed to
+   by *ROOTP.  If no matching entry is available return NULL.  */
+extern void *tfind __P ((__const void * __key, void *__const * __rootp,
 			 __compar_fn_t compar));
-extern void *__tfind __P ((__const void * __key, __const void ** __rootp,
+extern void *__tfind __P ((__const void * __key, void *__const * __rootp,
 			   __compar_fn_t compar));
 
+/* Remove the element matching KEY from the tree pointed to by *ROOTP.  */
 extern void *tdelete __P ((__const void * __key, void ** __rootp,
 			   __compar_fn_t compar));
 extern void *__tdelete __P ((__const void * __key, void ** __rootp,
@@ -128,10 +133,22 @@ typedef void (*__action_fn_t) __P ((__const void *__nodep,
 				    int __level));
 #endif
 
+/* Walk through the whole tree and call the ACTION callback for every node
+   or leaf.  */
 extern void twalk __P ((__const void * __root, __action_fn_t action));
 
 extern void __twalk __P ((__const void * __root, __action_fn_t action));
 
+#ifdef __USE_GNU
+/* Callback type for function to free a tree node.  If the keys are atomic
+   data this function should do nothing.  */
+typedef void (*__free_fn_t) __P ((void *__nodep));
+
+/* Destroy the whole tree, call FREEFCT for each node or leaf.  */
+extern void __tdestroy __P ((void *__root, __free_fn_t freefct));
+extern void tdestroy __P ((void *__root, __free_fn_t freefct));
+#endif
+
 
 /* Perform linear search for KEY by comparing by COMPAR in an array
    [BASE,BASE+NMEMB*SIZE).  */
diff --git a/misc/tsearch.c b/misc/tsearch.c
index 466536b..c06930d 100644
--- a/misc/tsearch.c
+++ b/misc/tsearch.c
@@ -300,7 +300,7 @@ weak_alias (__tsearch, tsearch)
 void *
 __tfind (key, vrootp, compar)
      const void *key;
-     const void **vrootp;
+     void *const *vrootp;
      __compar_fn_t compar;
 {
   node *rootp = (node *) vrootp;
@@ -625,3 +625,36 @@ __twalk (const void *vroot, __action_fn_t action)
     trecurse (root, action, 0);
 }
 weak_alias (__twalk, twalk)
+
+
+
+/* The standardized functions miss an important functionality: the
+   tree cannot be removed easily.  We provide a function to do this.  */
+static void
+tdestroy_recurse (node root, __free_fn_t freefct)
+{
+  if (root->left == NULL && root->right == NULL)
+    (*freefct) (root->key);
+  else
+    {
+      if (root->left != NULL)
+	tdestroy_recurse (root->left, freefct);
+      if (root->right != NULL)
+	tdestroy_recurse (root->right, freefct);
+      (*freefct) (root->key);
+    }
+  /* Free the node itself.  */
+  free (root);
+}
+
+void
+__tdestroy (void *vroot, __free_fn_t freefct)
+{
+  node root = (node) vroot;
+
+  CHECK_TREE (root);
+
+  if (root != NULL)
+    tdestroy_recurse (root, freefct);
+}
+weak_alias (__tdestroy, tdestroy)