misc: Add twalk_r function

The twalk function is very difficult to use in a multi-threaded
program because there is no way to pass external state to the
iterator function.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

37 files changed, 315 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index d30639a..4473569 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,72 @@
+2019-05-02  Florian Weimer  <fweimer@redhat.com>
+
+	misc: Add twalk_r function.
+	* include/search.h (__twalk_r): Declare.
+	* manual/examples/twalk.c: New file.
+	* manual/search.texi (Tree Search Function): Document twalk_r.
+	* misc/Versions (2.30): Export twalk_r.
+	(GLIBC_PRIVATE): Export __twalk_r.
+	* misc/search.h [__USE_GNU] (twalk_r): Declare.
+	* misc/tsearch.c (trecurse_r, __twalk_r): New functions.
+	(twalk_r): Add weak alias.
+	* misc/tst-tsearch.c (struct walk_trace_element): Define.
+	(walk_trace): New variable.
+	(struct twalk_with_twalk_r_closure): Define.
+	(twalk_with_twalk_r_action): New function.
+	(twalk_with_twalk_r): Likewise.
+	(walk_action): Call walk_trace_add.
+	(walk_tree_with): Rename from walk_tree.  Add walk argument.
+	(walk_tree): New function.
+	* sysdeps/mach/hurd/i386/libc.abilist (GLIBC_2.30): Add twalk_r.
+	* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/csky/libc.abilist (GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+	(GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.30): Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.30):
+	Likewise.
+	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.30):
+	Likewise.
+
 2019-04-30  Paul Eggert  <eggert@cs.ucla.edu>
 
 	Make mktime etc. compatible with __time64_t
diff --git a/NEWS b/NEWS
index 792ffb1..41cffa4 100644
--- a/NEWS
+++ b/NEWS
@@ -16,6 +16,10 @@ Major new features:
 * The dynamic linker accepts the --preload argument to preload shared
   objects, in addition to the LD_PRELOAD environment variable.
 
+* The twalk_r function has been added.  It is similar to the existing
+  twalk function, but it passes an additional caller-supplied argument
+  to the callback function.
+
 * On Linux, the gettid function has been added.
 
 * Minguo (Republic of China) calendar support has been added as an
diff --git a/include/search.h b/include/search.h
index e176930..72fbc94 100644
--- a/include/search.h
+++ b/include/search.h
@@ -23,6 +23,8 @@ extern void *__tdelete (const void *__key, void **__rootp,
 libc_hidden_proto (__tdelete)
 extern void __twalk (const void *__root, __action_fn_t action);
 libc_hidden_proto (__twalk)
+extern __typeof__ (twalk_r) __twalk_r;
+libc_hidden_proto (__twalk_r)
 extern void __tdestroy (void *__root, __free_fn_t freefct);
 libc_hidden_proto (__tdestroy)
 #endif
diff --git a/manual/examples/twalk.c b/manual/examples/twalk.c
new file mode 100644
index 0000000..04e3273
--- /dev/null
+++ b/manual/examples/twalk.c
@@ -0,0 +1,56 @@
+/* Implement twalk using twalk_r.
+   Copyright (C) 2019 Free Software Foundation, Inc.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <search.h>
+
+struct twalk_with_twalk_r_closure
+{
+  void (*action) (const void *, VISIT, int);
+  int depth;
+};
+
+static void
+twalk_with_twalk_r_action (const void *nodep, VISIT which, void *closure0)
+{
+  struct twalk_with_twalk_r_closure *closure = closure0;
+
+  switch (which)
+    {
+    case leaf:
+      closure->action (nodep, which, closure->depth);
+      break;
+    case preorder:
+      closure->action (nodep, which, closure->depth);
+      ++closure->depth;
+      break;
+    case postorder:
+      /* The preorder action incremented the depth.  */
+      closure->action (nodep, which, closure->depth - 1);
+      break;
+    case endorder:
+      --closure->depth;
+      closure->action (nodep, which, closure->depth);
+      break;
+    }
+}
+
+void
+twalk (const void *root, void (*action) (const void *, VISIT, int))
+{
+  struct twalk_with_twalk_r_closure closure = { action, 0 };
+  twalk_r (root, twalk_with_twalk_r_action, &closure);
+}
diff --git a/manual/search.texi b/manual/search.texi
index 1574c96..979732f 100644
--- a/manual/search.texi
+++ b/manual/search.texi
@@ -618,5 +618,28 @@ Since the functions used for the @var{action} parameter to @code{twalk}
 must not modify the tree data, it is safe to run @code{twalk} in more
 than one thread at the same time, working on the same tree.  It is also
 safe to call @code{tfind} in parallel.  Functions which modify the tree
-must not be used, otherwise the behavior is undefined.
+must not be used, otherwise the behavior is undefined.  However, it is
+difficult to pass data external to the tree to the callback function
+without resorting to global variables (and thread safety issues), so
+see the @code{twalk_r} function below.
+@end deftypefun
+
+@deftypefun void twalk_r (const void *@var{root}, void (*@var{action}) (const void *@var{key}, VISIT @var{which}, void *@var{closure}), void *@var{closure})
+@standards{GNU, search.h}
+@safety{@prelim{}@mtsafe{@mtsrace{:root}}@assafe{}@acsafe{}}
+For each node in the tree with a node pointed to by @var{root}, the
+@code{twalk_r} function calls the function provided by the parameter
+@var{action}.  For leaf nodes the function is called exactly once with
+@var{value} set to @code{leaf}.  For internal nodes the function is
+called three times, setting the @var{value} parameter or @var{action} to
+the appropriate value.  The @var{closure} parameter is passed down to
+each call of the @var{action} function, unmodified.
+
+It is possible to implement the @code{twalk} function on top of the
+@code{twalk_r} function, which is why there is no separate level
+parameter.
+
+@smallexample
+@include twalk.c.texi
+@end smallexample
 @end deftypefun
diff --git a/misc/Versions b/misc/Versions
index 900e4ff..e749582 100644
--- a/misc/Versions
+++ b/misc/Versions
@@ -158,11 +158,14 @@ libc {
   GLIBC_2.26 {
     preadv2; preadv64v2; pwritev2; pwritev64v2;
   }
+  GLIBC_2.30 {
+    twalk_r;
+  }
   GLIBC_PRIVATE {
     __madvise;
     __mktemp;
     __libc_ifunc_impl_list;
-    __tdelete; __tfind; __tsearch; __twalk;
+    __tdelete; __tfind; __tsearch; __twalk; __twalk_r;
     __mmap; __munmap; __mprotect;
     __sched_get_priority_min; __sched_get_priority_max;
     __libc_allocate_once_slow;
diff --git a/misc/search.h b/misc/search.h
index 47e8a43..4659c59 100644
--- a/misc/search.h
+++ b/misc/search.h
@@ -150,6 +150,13 @@ typedef void (*__action_fn_t) (const void *__nodep, VISIT __value,
 extern void twalk (const void *__root, __action_fn_t __action);
 
 #ifdef __USE_GNU
+/* Like twalk, but pass down a closure parameter instead of the
+   level.  */
+extern void twalk_r (const void *__root,
+		     void (*) (const void *__nodep, VISIT __value,
+			       void *__closure),
+		     void *__closure);
+
 /* 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) (void *__nodep);
diff --git a/misc/tsearch.c b/misc/tsearch.c
index 5c19082..edf0fec 100644
--- a/misc/tsearch.c
+++ b/misc/tsearch.c
@@ -719,7 +719,41 @@ __twalk (const void *vroot, __action_fn_t action)
 libc_hidden_def (__twalk)
 weak_alias (__twalk, twalk)
 
+/* twalk_r is the same as twalk, but with a closure parameter instead
+   of the level.  */
+static void
+trecurse_r (const void *vroot, void (*action) (const void *, VISIT, void *),
+	    void *closure)
+{
+  const_node root = (const_node) vroot;
 
+  if (LEFT(root) == NULL && RIGHT(root) == NULL)
+    (*action) (root, leaf, closure);
+  else
+    {
+      (*action) (root, preorder, closure);
+      if (LEFT(root) != NULL)
+	trecurse_r (LEFT(root), action, closure);
+      (*action) (root, postorder, closure);
+      if (RIGHT(root) != NULL)
+	trecurse_r (RIGHT(root), action, closure);
+      (*action) (root, endorder, closure);
+    }
+}
+
+void
+__twalk_r (const void *vroot, void (*action) (const void *, VISIT, void *),
+	   void *closure)
+{
+  const_node root = (const_node) vroot;
+
+  CHECK_TREE ((node) root);
+
+  if (root != NULL && action != NULL)
+    trecurse_r (root, action, closure);
+}
+libc_hidden_def (__twalk_r)
+weak_alias (__twalk_r, twalk_r)
 
 /* The standardized functions miss an important functionality: the
    tree cannot be removed easily.  We provide a function to do this.  */
diff --git a/misc/tst-tsearch.c b/misc/tst-tsearch.c
index 5803a45..9a570dd 100644
--- a/misc/tst-tsearch.c
+++ b/misc/tst-tsearch.c
@@ -25,6 +25,7 @@
 #include <string.h>
 #include <search.h>
 #include <tst-stack-align.h>
+#include <support/check.h>
 
 #define SEED 0
 #define BALANCED 1
@@ -74,6 +75,20 @@ static int max_depth;
 
 static int stack_align_check[2];
 
+/* Used to compare walk traces between the two implementations.  */
+struct walk_trace_element
+{
+  const void *key;
+  VISIT which;
+  int depth;
+};
+#define DYNARRAY_STRUCT walk_trace_list
+#define DYNARRAY_ELEMENT struct walk_trace_element
+#define DYNARRAY_PREFIX walk_trace_
+#define DYNARRAY_INITIAL_SIZE 0
+#include <malloc/dynarray-skeleton.c>
+static struct walk_trace_list walk_trace;
+
 /* Compare two keys.  */
 static int
 cmp_fn (const void *a, const void *b)
@@ -102,11 +117,54 @@ memfry (int *string)
     }
 }
 
+struct twalk_with_twalk_r_closure
+{
+  void (*action) (const void *, VISIT, int);
+  int depth;
+};
+
+static void
+twalk_with_twalk_r_action (const void *nodep, VISIT which, void *closure0)
+{
+  struct twalk_with_twalk_r_closure *closure = closure0;
+
+  switch (which)
+    {
+    case leaf:
+      closure->action (nodep, which, closure->depth);
+      break;
+    case preorder:
+      closure->action (nodep, which, closure->depth);
+      ++closure->depth;
+      break;
+    case postorder:
+      /* The preorder action incremented the depth.  */
+      closure->action (nodep, which, closure->depth - 1);
+      break;
+    case endorder:
+      --closure->depth;
+      closure->action (nodep, which, closure->depth);
+      break;
+    }
+}
+
+static void
+twalk_with_twalk_r (const void *root,
+		    void (*action) (const void *, VISIT, int))
+{
+  struct twalk_with_twalk_r_closure closure = { action, 0 };
+  twalk_r (root, twalk_with_twalk_r_action, &closure);
+  TEST_COMPARE (closure.depth, 0);
+}
+
 static void
 walk_action (const void *nodep, const VISIT which, const int depth)
 {
   int key = **(int **) nodep;
 
+  walk_trace_add (&walk_trace,
+		  (struct walk_trace_element) { nodep, which, depth });
+
   if (!stack_align_check[1])
     stack_align_check[1] = TEST_STACK_ALIGN () ? -1 : 1;
 
@@ -128,14 +186,16 @@ walk_action (const void *nodep, const VISIT which, const int depth)
 }
 
 static void
-walk_tree (void *root, int expected_count)
+walk_tree_with (void *root, int expected_count,
+		void (*walk) (const void *,
+			      void (*) (const void *, VISIT, int)))
 {
   int i;
 
   memset (z, 0, sizeof z);
   max_depth = 0;
 
-  twalk (root, walk_action);
+  walk (root, walk_action);
   for (i = 0; i < expected_count; ++i)
     if (z[i] != 1)
       {
@@ -154,6 +214,31 @@ walk_tree (void *root, int expected_count)
     }
 }
 
+static void
+walk_tree (void *root, int expected_count)
+{
+  walk_trace_clear (&walk_trace);
+  walk_tree_with (root, expected_count, twalk);
+  TEST_VERIFY (!walk_trace_has_failed (&walk_trace));
+  size_t first_list_size;
+  struct walk_trace_element *first_list
+    = walk_trace_finalize (&walk_trace, &first_list_size);
+
+  walk_tree_with (root, expected_count, twalk_with_twalk_r);
+
+  /* Compare the two traces.  */
+  TEST_COMPARE (first_list_size, walk_trace_size (&walk_trace));
+  for (size_t i = 0; i < first_list_size && i < walk_trace_size (&walk_trace);
+       ++i)
+    {
+      TEST_VERIFY (first_list[i].key == walk_trace_at (&walk_trace, i)->key);
+      TEST_COMPARE (first_list[i].which, walk_trace_at (&walk_trace, i)->which);
+      TEST_COMPARE (first_list[i].depth, walk_trace_at (&walk_trace, i)->depth);
+    }
+
+  walk_trace_free (&walk_trace);
+}
+
 /* Perform an operation on a tree.  */
 static void
 mangle_tree (enum order how, enum action what, void **root, int lag)
diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist
index dd3cf6f..1fc7ab2 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -2175,6 +2175,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
 GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index f3b44d7..b7283ad 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2142,3 +2142,4 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index fd81fc4..a817e68 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2217,6 +2217,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
index f451fef..97b6cbf 100644
--- a/sysdeps/unix/sysv/linux/arm/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
@@ -127,6 +127,7 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0xa0
 GLIBC_2.4 _IO_2_1_stdin_ D 0xa0
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 018d02b..796e622 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2086,3 +2086,4 @@ GLIBC_2.29 xencrypt F
 GLIBC_2.29 xprt_register F
 GLIBC_2.29 xprt_unregister F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index fc3c5d5..4e7d71d 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2038,6 +2038,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index f2b04db..11bd8c6 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2204,6 +2204,7 @@ GLIBC_2.3.4 vm86 F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 10ecf2e..589cce5 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2070,6 +2070,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 814e81b..4b3727a 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -128,6 +128,7 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _Exit F
 GLIBC_2.4 _IO_2_1_stderr_ D 0x98
 GLIBC_2.4 _IO_2_1_stdin_ D 0x98
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index 68e8037..4be30c0 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2147,6 +2147,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
index 31178e4..e001096 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
@@ -2134,3 +2134,4 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 7074573..2a62f67 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2121,6 +2121,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
index 154f9c7..5a23f11 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2119,6 +2119,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
index 97b8f42..32532a1 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -2127,6 +2127,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
index 5b3e85d..882f5cb 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -2121,6 +2121,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index 04a130a..c99a299 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2175,3 +2175,4 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index a701584..d5f4364 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -2177,6 +2177,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index bbb647c..581fd10 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -2210,6 +2210,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
index bb23bf6..ce10e04 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
@@ -2040,6 +2040,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
index 7921dda..1cc729d 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
@@ -2244,3 +2244,4 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index da123d3..2bda569 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2104,3 +2104,4 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index 2aed339..dddc138 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2172,6 +2172,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index e46feb5..b2c75a4 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -2076,6 +2076,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
index 24a8f93..8b83449 100644
--- a/sysdeps/unix/sysv/linux/sh/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
@@ -2042,6 +2042,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index ebdbd2c..a237be9 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -2166,6 +2166,7 @@ GLIBC_2.30 __nldbl_vwarnx F
 GLIBC_2.30 __nldbl_warn F
 GLIBC_2.30 __nldbl_warnx F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 _IO_fprintf F
 GLIBC_2.4 _IO_printf F
 GLIBC_2.4 _IO_sprintf F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index 0992349..b850694 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -2093,6 +2093,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index af004fc..c6f22f0 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -2051,6 +2051,7 @@ GLIBC_2.3.4 setsourcefilter F
 GLIBC_2.3.4 xdr_quad_t F
 GLIBC_2.3.4 xdr_u_quad_t F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F
 GLIBC_2.4 __confstr_chk F
 GLIBC_2.4 __fgets_chk F
 GLIBC_2.4 __fgets_unlocked_chk F
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
index 84015f0..1184385 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2150,3 +2150,4 @@ GLIBC_2.29 getcpu F
 GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.30 gettid F
+GLIBC_2.30 twalk_r F