[v2,2/3] posix: Add pidfd_fork

diff --git a/NEWS b/NEWS
index 081d0180f4..2ac69a8a2c 100644
--- a/NEWS
+++ b/NEWS
@@ -28,6 +28,11 @@  Major new features:
   The pidfd functionality avoid the issue of PID reuse with traditional
   posix_spawn interface.
 
+* On Linux, the pidfd_fork has been added.  It has a similar semantic
+  as fork or _Fork, where it clone the calling process.  However instead of
+  return a process ID, it returns a file descriptor that can be used along
+  other pidfd functions.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
 * In the Linux kernel for the hppa/parisc architecture some of the
diff --git a/manual/process.texi b/manual/process.texi
index 927aebbe3d..410e91202c 100644
--- a/manual/process.texi
+++ b/manual/process.texi
@@ -137,12 +137,12 @@  creating a process and making it run another program.
 @cindex subprocess
 A new processes is created when one of the functions
 @code{posix_spawn}, @code{fork}, @code{_Fork}, @code{vfork}, or
-@code{pidfd_spawn} is called.  (The @code{system} and @code{popen} also
-create new processes internally.)  Due to the name of the @code{fork}
-function, the act of creating a new process is sometimes called
-@dfn{forking} a process.  Each new process (the @dfn{child process} or
-@dfn{subprocess}) is allocated a process ID, distinct from the process
-ID of the parent process.  @xref{Process Identification}.
+@code{pidfd_spawn}, or @code{pidfd_fork} is called.  (The @code{system}
+and @code{popen} also create new processes internally.)  Due to the name
+of the @code{fork} function, the act of creating a new process is
+sometimes called @dfn{forking} a process.  Each new process (the
+@dfn{child process} or @dfn{subprocess}) is allocated a process ID,
+distinct from the process ID of the parent process.  @xref{Process Identification}.
 
 After forking a child process, both the parent and child processes
 continue to execute normally.  If you want your program to wait for a
@@ -153,10 +153,10 @@  limited information about why the child terminated---for example, its
 exit status code.
 
 A newly forked child process continues to execute the same program as
-its parent process, at the point where the @code{fork} or @code{_Fork}
-call returns.  You can use the return value from @code{fork} or
-@code{_Fork} to tell whether the program is running in the parent process
-or the child.
+its parent process, at the point where the @code{fork}, @code{_Fork},
+or @code{pidfd_fork} call returns.  You can use the return value from
+@code{fork}, @code{_Fork}, or @code{pidfd_fork} to tell whether the
+program is running in the parent process or the child.
 
 @cindex process image
 Having several processes run the same program is only occasionally
diff --git a/posix/Makefile b/posix/Makefile
index 4016a7758a..c4837589fd 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -84,6 +84,7 @@  routines := \
   fexecve \
   fnmatch \
   fork \
+  fork-internal \
   fpathconf \
   gai_strerror \
   get_child_max \
@@ -579,7 +580,7 @@  CFLAGS-execl.os = -fomit-frame-pointer
 CFLAGS-execvp.os = -fomit-frame-pointer
 CFLAGS-execlp.os = -fomit-frame-pointer
 CFLAGS-nanosleep.c += -fexceptions -fasynchronous-unwind-tables
-CFLAGS-fork.c = $(libio-mtsafe) $(config-cflags-wno-ignored-attributes)
+CFLAGS-fork-internal.c = $(libio-mtsafe) $(config-cflags-wno-ignored-attributes)
 
 tstgetopt-ARGS = -a -b -cfoobar --required foobar --optional=bazbug \
 		--none random --col --color --colour
diff --git a/posix/fork-internal.c b/posix/fork-internal.c
new file mode 100644
index 0000000000..be0d3219af
--- /dev/null
+++ b/posix/fork-internal.c
@@ -0,0 +1,125 @@ 
+/* Internal fork definitions.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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 Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <fork.h>
+#include <fork-internal.h>
+#include <ldsodefs.h>
+#include <libio/libioP.h>
+#include <malloc/malloc-internal.h>
+#include <register-atfork.h>
+#include <stdio-lock.h>
+#include <unwind-link.h>
+
+static void
+fresetlockfiles (void)
+{
+  _IO_ITER i;
+
+  for (i = _IO_iter_begin(); i != _IO_iter_end(); i = _IO_iter_next(i))
+    if ((_IO_iter_file (i)->_flags & _IO_USER_LOCK) == 0)
+      _IO_lock_init (*((_IO_lock_t *) _IO_iter_file(i)->_lock));
+}
+
+uint64_t
+__fork_pre (bool multiple_threads, struct nss_database_data *nss_database_data)
+{
+  uint64_t lastrun = __run_prefork_handlers (multiple_threads);
+
+  /* If we are not running multiple threads, we do not have to
+     preserve lock state.  If fork runs from a signal handler, only
+     async-signal-safe functions can be used in the child.  These data
+     structures are only used by unsafe functions, so their state does
+     not matter if fork was called from a signal handler.  */
+  if (multiple_threads)
+    {
+      call_function_static_weak (__nss_database_fork_prepare_parent,
+				 nss_database_data);
+
+      _IO_list_lock ();
+
+      /* Acquire malloc locks.  This needs to come last because fork
+	 handlers may use malloc, and the libio list lock has an
+	 indirect malloc dependency as well (via the getdelim
+	 function).  */
+      call_function_static_weak (__malloc_fork_lock_parent);
+    }
+
+  return lastrun;
+}
+
+void
+__fork_pos (int state, uint64_t lastrun, bool multiple_threads,
+	    struct nss_database_data *nss_database_data)
+{
+  if (state == 0)
+    {
+      fork_system_setup ();
+
+      /* Reset the lock state in the multi-threaded case.  */
+      if (multiple_threads)
+	{
+	  __libc_unwind_link_after_fork ();
+
+	  fork_system_setup_after_fork ();
+
+	  /* Release malloc locks.  */
+	  call_function_static_weak (__malloc_fork_unlock_child);
+
+	  /* Reset the file list.  These are recursive mutexes.  */
+	  fresetlockfiles ();
+
+	  /* Reset locks in the I/O code.  */
+	  _IO_list_resetlock ();
+
+	  call_function_static_weak (__nss_database_fork_subprocess,
+				     nss_database_data);
+	}
+
+      /* Reset the lock the dynamic loader uses to protect its data.  */
+      __rtld_lock_initialize (GL(dl_load_lock));
+
+      /* Reset the lock protecting dynamic TLS related data.  */
+      __rtld_lock_initialize (GL(dl_load_tls_lock));
+
+      reclaim_stacks ();
+
+      /* Run the handlers registered for the child.  */
+      __run_postfork_handlers (atfork_run_child, multiple_threads, lastrun);
+    }
+  else
+    {
+      /* If _Fork failed, preserve its errno value.  */
+      int save_errno = errno;
+
+      /* Release acquired locks in the multi-threaded case.  */
+      if (multiple_threads)
+	{
+	  /* Release malloc locks, parent process variant.  */
+	  call_function_static_weak (__malloc_fork_unlock_parent);
+
+	  /* We execute this even if the 'fork' call failed.  */
+	  _IO_list_unlock ();
+	}
+
+      /* Run the handlers registered for the parent.  */
+      __run_postfork_handlers (atfork_run_parent, multiple_threads, lastrun);
+
+      if (state < 0)
+	__set_errno (save_errno);
+    }
+}
diff --git a/posix/fork-internal.h b/posix/fork-internal.h
new file mode 100644
index 0000000000..3814d851c4
--- /dev/null
+++ b/posix/fork-internal.h
@@ -0,0 +1,29 @@ 
+/* Internal fork definitions.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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 Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _FORK_INTERNAL_H
+#define _FORK_INTERNAL_H
+
+#include <stdint.h>
+#include <nss/nss_database.h>
+
+uint64_t __fork_pre (bool, struct nss_database_data *) attribute_hidden;
+void __fork_pos (int, uint64_t, bool, struct nss_database_data *)
+  attribute_hidden;
+
+#endif
diff --git a/posix/fork.c b/posix/fork.c
index b4aaa9fa6d..4423cc5792 100644
--- a/posix/fork.c
+++ b/posix/fork.c
@@ -16,25 +16,10 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <fork.h>
-#include <libio/libioP.h>
-#include <ldsodefs.h>
-#include <malloc/malloc-internal.h>
-#include <nss/nss_database.h>
-#include <register-atfork.h>
-#include <stdio-lock.h>
+#include <fork-internal.h>
 #include <sys/single_threaded.h>
 #include <unwind-link.h>
-
-static void
-fresetlockfiles (void)
-{
-  _IO_ITER i;
-
-  for (i = _IO_iter_begin(); i != _IO_iter_end(); i = _IO_iter_next(i))
-    if ((_IO_iter_file (i)->_flags & _IO_USER_LOCK) == 0)
-      _IO_lock_init (*((_IO_lock_t *) _IO_iter_file(i)->_lock));
-}
+#include <unistd.h>
 
 pid_t
 __libc_fork (void)
@@ -46,89 +31,14 @@  __libc_fork (void)
      best effort to make is async-signal-safe at least for single-thread
      case.  */
   bool multiple_threads = !SINGLE_THREAD_P;
-  uint64_t lastrun;
-
-  lastrun = __run_prefork_handlers (multiple_threads);
 
   struct nss_database_data nss_database_data;
 
-  /* If we are not running multiple threads, we do not have to
-     preserve lock state.  If fork runs from a signal handler, only
-     async-signal-safe functions can be used in the child.  These data
-     structures are only used by unsafe functions, so their state does
-     not matter if fork was called from a signal handler.  */
-  if (multiple_threads)
-    {
-      call_function_static_weak (__nss_database_fork_prepare_parent,
-				 &nss_database_data);
-
-      _IO_list_lock ();
-
-      /* Acquire malloc locks.  This needs to come last because fork
-	 handlers may use malloc, and the libio list lock has an
-	 indirect malloc dependency as well (via the getdelim
-	 function).  */
-      call_function_static_weak (__malloc_fork_lock_parent);
-    }
+  uint64_t lastrun = __fork_pre (multiple_threads, &nss_database_data);
 
   pid_t pid = _Fork ();
 
-  if (pid == 0)
-    {
-      fork_system_setup ();
-
-      /* Reset the lock state in the multi-threaded case.  */
-      if (multiple_threads)
-	{
-	  __libc_unwind_link_after_fork ();
-
-	  fork_system_setup_after_fork ();
-
-	  /* Release malloc locks.  */
-	  call_function_static_weak (__malloc_fork_unlock_child);
-
-	  /* Reset the file list.  These are recursive mutexes.  */
-	  fresetlockfiles ();
-
-	  /* Reset locks in the I/O code.  */
-	  _IO_list_resetlock ();
-
-	  call_function_static_weak (__nss_database_fork_subprocess,
-				     &nss_database_data);
-	}
-
-      /* Reset the lock the dynamic loader uses to protect its data.  */
-      __rtld_lock_initialize (GL(dl_load_lock));
-
-      /* Reset the lock protecting dynamic TLS related data.  */
-      __rtld_lock_initialize (GL(dl_load_tls_lock));
-
-      reclaim_stacks ();
-
-      /* Run the handlers registered for the child.  */
-      __run_postfork_handlers (atfork_run_child, multiple_threads, lastrun);
-    }
-  else
-    {
-      /* If _Fork failed, preserve its errno value.  */
-      int save_errno = errno;
-
-      /* Release acquired locks in the multi-threaded case.  */
-      if (multiple_threads)
-	{
-	  /* Release malloc locks, parent process variant.  */
-	  call_function_static_weak (__malloc_fork_unlock_parent);
-
-	  /* We execute this even if the 'fork' call failed.  */
-	  _IO_list_unlock ();
-	}
-
-      /* Run the handlers registered for the parent.  */
-      __run_postfork_handlers (atfork_run_parent, multiple_threads, lastrun);
-
-      if (pid < 0)
-	__set_errno (save_errno);
-    }
+  __fork_pos (pid, lastrun, multiple_threads, &nss_database_data);
 
   return pid;
 }
diff --git a/sysdeps/mach/hurd/bits/errno.h b/sysdeps/mach/hurd/bits/errno.h
index 0d935e724a..069865189f 100644
--- a/sysdeps/mach/hurd/bits/errno.h
+++ b/sysdeps/mach/hurd/bits/errno.h
@@ -9,6 +9,25 @@ 
      mach/boolean.h
      mach/i386/boolean.h
      mach/i386/vm_types.h
+     stdint.h
+     ../stdlib/stdint.h
+     ../bits/libc-header-start.h
+     features.h
+     features-time64.h
+     ../sysdeps/generic/features-time64.h
+     sys/cdefs.h
+     ../misc/sys/cdefs.h
+     ../sysdeps/x86/bits/wordsize.h
+     ../sysdeps/ieee754/ldbl-96/bits/long-double.h
+     gnu/stubs.h
+     bits/types.h
+     ../posix/bits/types.h
+     ../sysdeps/mach/hurd/bits/timesize.h
+     ../sysdeps/mach/hurd/bits/typesizes.h
+     ../bits/time64.h
+     ../bits/wchar.h
+     ../bits/stdint-intn.h
+     ../bits/stdint-uintn.h
      mach/mig_errors.h
      device/device_types.h
      mach/std_types.h
diff --git a/sysdeps/nptl/_Fork.c b/sysdeps/nptl/_Fork.c
index f8322ae557..aa99e05b5b 100644
--- a/sysdeps/nptl/_Fork.c
+++ b/sysdeps/nptl/_Fork.c
@@ -22,7 +22,7 @@ 
 pid_t
 _Fork (void)
 {
-  pid_t pid = arch_fork (&THREAD_SELF->tid);
+  pid_t pid = arch_fork (0, NULL, &THREAD_SELF->tid);
   if (pid == 0)
     {
       struct pthread *self = THREAD_SELF;
diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 376e5d622d..c5cef27244 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -491,14 +491,17 @@  sysdep_headers += \
 sysdep_routines += \
   getcpu \
   oldglob \
+  pidfd_fork \
   pidfd_spawn \
   pidfd_spawnp \
   sched_getcpu \
+  sched_getcpu \
   # sysdep_routines
 
 tests += \
   tst-affinity \
   tst-affinity-pid \
+  tst-pidfd_fork \
   tst-posix_spawn-setsid-pidfd \
   tst-spawn-chdir-pidfd \
   tst-spawn-pidfd \
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index 28825473ae..7e4109e9c5 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -322,6 +322,7 @@  libc {
 %endif
   }
   GLIBC_2.38 {
+    pidfd_fork;
     pidfd_spawn;
     pidfd_spawnp;
   }
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index bac74ae474..dbf7c44319 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2665,5 +2665,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index dadd302f8d..a9d6ffce14 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2774,6 +2774,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist
index 0f4f07b6bb..c08d548556 100644
--- a/sysdeps/unix/sysv/linux/arc/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arc/libc.abilist
@@ -2426,5 +2426,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/arch-fork.h b/sysdeps/unix/sysv/linux/arch-fork.h
index 84e5ef5a7f..ce08fdb99e 100644
--- a/sysdeps/unix/sysv/linux/arch-fork.h
+++ b/sysdeps/unix/sysv/linux/arch-fork.h
@@ -32,24 +32,24 @@ 
    override it with one of the supported calling convention (check generic
    kernel-features.h for the clone abi variants).  */
 static inline pid_t
-arch_fork (void *ctid)
+arch_fork (int flags, void *ptid, void *ctid)
 {
-  const int flags = CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD;
   long int ret;
+  flags |= CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID | SIGCHLD;
 #ifdef __ASSUME_CLONE_BACKWARDS
 # ifdef INLINE_CLONE_SYSCALL
-  ret = INLINE_CLONE_SYSCALL (flags, 0, NULL, 0, ctid);
+  ret = INLINE_CLONE_SYSCALL (flags, 0, ptid, 0, ctid);
 # else
-  ret = INLINE_SYSCALL_CALL (clone, flags, 0, NULL, 0, ctid);
+  ret = INLINE_SYSCALL_CALL (clone, flags, 0, ptid, 0, ctid);
 # endif
 #elif defined(__ASSUME_CLONE_BACKWARDS2)
-  ret = INLINE_SYSCALL_CALL (clone, 0, flags, NULL, ctid, 0);
+  ret = INLINE_SYSCALL_CALL (clone, 0, flags, ptid, ctid, 0);
 #elif defined(__ASSUME_CLONE_BACKWARDS3)
-  ret = INLINE_SYSCALL_CALL (clone, flags, 0, 0, NULL, ctid, 0);
+  ret = INLINE_SYSCALL_CALL (clone, flags, 0, 0, ptid, ctid, 0);
 #elif defined(__ASSUME_CLONE2)
-  ret = INLINE_SYSCALL_CALL (clone2, flags, 0, 0, NULL, ctid, 0);
+  ret = INLINE_SYSCALL_CALL (clone2, flags, 0, 0, ptid, ctid, 0);
 #elif defined(__ASSUME_CLONE_DEFAULT)
-  ret = INLINE_SYSCALL_CALL (clone, flags, 0, NULL, ctid, 0);
+  ret = INLINE_SYSCALL_CALL (clone, flags, 0, ptid, ctid, 0);
 #else
 # error "Undefined clone variant"
 #endif
diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
index 38e5dcb81a..f348336ee7 100644
--- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
@@ -546,6 +546,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _Exit F
diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
index 423d20cbb5..5aed593521 100644
--- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
@@ -543,6 +543,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _Exit F
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 488418d14e..8a7022aaa8 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2702,5 +2702,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 75d495e1c7..e2ac6949df 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2651,6 +2651,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index e53877c52a..5e8d49fc1f 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2835,6 +2835,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 5ed2b1ebf4..3cd3c80334 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2600,6 +2600,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist b/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist
index d050fbf6d0..0965db2ff0 100644
--- a/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/loongarch/lp64/libc.abilist
@@ -2186,5 +2186,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 6465af266c..1ec24886a3 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -547,6 +547,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _Exit F
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index 00013cc564..239b1d70be 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2778,6 +2778,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
index 34085d81ab..dd41d63394 100644
--- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
@@ -2751,5 +2751,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
index b26b116f1f..55c3dcd471 100644
--- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
@@ -2748,5 +2748,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index c86418d156..295e4d8608 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2743,6 +2743,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_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 3c6f8f4d60..19fb1aebe7 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2741,6 +2741,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_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 8dfa065638..2dd6ef5416 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -2749,6 +2749,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_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 0ca815f2cd..6445d27220 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -2651,6 +2651,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
index a1e0f772c6..c1cc5134c9 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2790,5 +2790,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/or1k/libc.abilist b/sysdeps/unix/sysv/linux/or1k/libc.abilist
index 91cd6075b9..293643346a 100644
--- a/sysdeps/unix/sysv/linux/or1k/libc.abilist
+++ b/sysdeps/unix/sysv/linux/or1k/libc.abilist
@@ -2172,5 +2172,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/pidfd_fork.c b/sysdeps/unix/sysv/linux/pidfd_fork.c
new file mode 100644
index 0000000000..56aa88b9a2
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/pidfd_fork.c
@@ -0,0 +1,76 @@ 
+/* pidfd_fork - Duplicated calling process and return a process file
+   descriptor.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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 Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <arch-fork.h>
+#include <clone_internal.h>
+#include <fork-internal.h>
+#include <sys/pidfd.h>
+
+static int
+forkfd (void)
+{
+  /* The kernel should not change the pidfd for the child, and the returning
+     value on the parent is always larger than 0 (since a new file descriptor
+     is always opened with CLONE_PIDFD is the kernel supports it.  */
+  int pidfd = 0;
+  int ret = arch_fork (CLONE_PIDFD, &pidfd, &THREAD_SELF->tid);
+  if (ret < 0)
+    return -1;
+  else if (ret == 0)
+    {
+      struct pthread *self = THREAD_SELF;
+
+      /* Initialize the robust mutex, check _Fork implementation for a full
+	 description why this is required.  */
+#if __PTHREAD_MUTEX_HAVE_PREV
+      self->robust_prev = &self->robust_head;
+#endif
+      self->robust_head.list = &self->robust_head;
+      INTERNAL_SYSCALL_CALL (set_robust_list, &self->robust_head,
+			     sizeof (struct robust_list_head));
+    }
+  return pidfd;
+}
+
+int
+pidfd_fork (unsigned int flags)
+{
+  if (!__clone_pidfd_supported ())
+    return INLINE_SYSCALL_ERROR_RETURN_VALUE (ENOSYS);
+
+  if (flags & ~(PIDFDFORK_RUNATFORK))
+    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
+
+  int pidfd;
+  if (flags & PIDFDFORK_RUNATFORK)
+    {
+      bool multiple_threads = !SINGLE_THREAD_P;
+      struct nss_database_data nss_database_data;
+
+      uint64_t lastrun = __fork_pre (multiple_threads, &nss_database_data);
+      pidfd = forkfd ();
+      /* It follow the usual fork semantic, where a positive or negative
+	 value is returned to parent, and 0 for the child.  */
+      __fork_pos (pidfd, lastrun, multiple_threads, &nss_database_data);
+    }
+  else
+    pidfd = forkfd ();
+
+  return pidfd;
+}
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index 21244ece27..03a35e860d 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -2817,6 +2817,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
index 238d00998b..a91af4245b 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -2850,6 +2850,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
index 36fb9b57ac..c15137b9ad 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
@@ -2571,6 +2571,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
index 0c25995661..12c0f4cfba 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
@@ -2885,5 +2885,6 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
index cda030f623..9537dac42d 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
@@ -2428,5 +2428,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index bd20c202fb..ea72e6b648 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2628,5 +2628,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index a1e9247f72..d6c895b487 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2815,6 +2815,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
index b80a131bde..b375f5a7ab 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -2608,6 +2608,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/sh/be/libc.abilist b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
index 496a0185b6..7b2266ecb3 100644
--- a/sysdeps/unix/sysv/linux/sh/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
@@ -2658,6 +2658,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/sh/le/libc.abilist b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
index 3e0d858d08..2f9f732044 100644
--- a/sysdeps/unix/sysv/linux/sh/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
@@ -2655,6 +2655,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
index 84dcda8db2..144d54ebf2 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -2810,6 +2810,7 @@  GLIBC_2.38 __nldbl___isoc23_vsscanf F
 GLIBC_2.38 __nldbl___isoc23_vswscanf F
 GLIBC_2.38 __nldbl___isoc23_vwscanf F
 GLIBC_2.38 __nldbl___isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 _IO_fprintf F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
index 1688a0a7e9..bc8bd8ff54 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -2623,6 +2623,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/sys/pidfd.h b/sysdeps/unix/sysv/linux/sys/pidfd.h
index 342e593288..e5c3bdb788 100644
--- a/sysdeps/unix/sysv/linux/sys/pidfd.h
+++ b/sysdeps/unix/sysv/linux/sys/pidfd.h
@@ -46,4 +46,17 @@  extern int pidfd_getfd (int __pidfd, int __targetfd,
 extern int pidfd_send_signal (int __pidfd, int __sig, siginfo_t *__info,
 			      unsigned int __flags) __THROW;
 
+
+/* Issue the pthread_atfork on pidfd_fork.  */
+#define PIDFDFORK_RUNATFORK  (1U << 1)
+
+/* Clone the calling process, creating an exact copy.
+
+   The __FLAGS can be used to specify whether the pthread_atfork handlers will
+   be issued.  The default is to not run it, similar to _Fork.
+
+   Return -1 for errors, 0 to the new process, and the process file descriptor
+   of the new process to the parent process.  */
+extern int pidfd_fork (unsigned int __flags) __THROW;
+
 #endif /* _PIDFD_H  */
diff --git a/sysdeps/unix/sysv/linux/tst-pidfd_fork.c b/sysdeps/unix/sysv/linux/tst-pidfd_fork.c
new file mode 100644
index 0000000000..89d78a4e13
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-pidfd_fork.c
@@ -0,0 +1,150 @@ 
+/* Basic tests for pidfd_fork.
+   Copyright (C) 2023 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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 Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <array_length.h>
+#include <errno.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/temp_file.h>
+#include <support/xunistd.h>
+#include <sys/pidfd.h>
+#include <sys/wait.h>
+
+#define SIG_PID_EXIT_CODE 20
+
+static bool atfork_prepare_var;
+static bool atfork_parent_var;
+static bool atfork_child_var;
+
+static void
+atfork_prepare (void)
+{
+  atfork_prepare_var = true;
+}
+
+static void
+atfork_parent (void)
+{
+  atfork_parent_var = true;
+}
+
+static void
+atfork_child (void)
+{
+  atfork_child_var = true;
+}
+
+static int
+singlethread_test (unsigned int flags)
+{
+  const char testdata1[] = "abcdefghijklmnopqrtuvwxz";
+  enum { testdatalen1 = array_length (testdata1) };
+  const char testdata2[] = "01234567890";
+  enum { testdatalen2 = array_length (testdata2) };
+
+  pid_t ppid = getpid ();
+
+  int tempfd = create_temp_file ("tst-pidfd_fork", NULL);
+
+  /* Check if the opened file is shared between process by read and write
+     some data on parent and child processes.  */
+  xwrite (tempfd, testdata1, testdatalen1);
+  off_t off = xlseek (tempfd, 0, SEEK_CUR);
+  TEST_COMPARE (off, testdatalen1);
+
+  int pidfd = pidfd_fork (flags);
+  if (pidfd == -1 && errno == ENOSYS)
+    FAIL_UNSUPPORTED ("kernel does not support CLONE_PIDFD clone flag");
+  TEST_VERIFY_EXIT (pidfd != -1);
+
+  if (pidfd == 0)
+    {
+      if (flags & PIDFDFORK_RUNATFORK)
+	TEST_VERIFY (atfork_child_var);
+      else
+	TEST_VERIFY (!atfork_child_var);
+
+      TEST_VERIFY_EXIT (getpid () != ppid);
+      TEST_COMPARE (getppid(), ppid);
+
+      TEST_COMPARE (xlseek (tempfd, 0, SEEK_CUR), testdatalen1);
+
+      xlseek (tempfd, 0, SEEK_SET);
+      char buf[testdatalen1];
+      TEST_COMPARE (read (tempfd, buf, sizeof (buf)), testdatalen1);
+      TEST_COMPARE_BLOB (buf, testdatalen1, testdata1, testdatalen1);
+
+      xlseek (tempfd, 0, SEEK_SET);
+      xwrite (tempfd, testdata2, testdatalen2);
+
+      xclose (tempfd);
+
+      _exit (EXIT_SUCCESS);
+    }
+  else
+    TEST_VERIFY_EXIT (pidfd != -1);
+
+  {
+    siginfo_t sinfo;
+    TEST_COMPARE (waitid (P_PIDFD, pidfd, &sinfo, WEXITED), 0);
+    TEST_COMPARE (sinfo.si_code, CLD_EXITED);
+    TEST_COMPARE (sinfo.si_status, 0);
+  }
+
+  TEST_COMPARE (xlseek (tempfd, 0, SEEK_CUR), testdatalen2);
+
+  xlseek (tempfd, 0, SEEK_SET);
+  char buf[testdatalen2];
+  TEST_COMPARE (read (tempfd, buf, sizeof (buf)), testdatalen2);
+
+  TEST_COMPARE_BLOB (buf, testdatalen2, testdata2, testdatalen2);
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  pthread_atfork (atfork_prepare, atfork_parent, atfork_child);
+
+  /* With default flags, pidfd_fork acts as _Fork and do not run the
+     pthread_atfork handlers.  */
+  {
+    atfork_prepare_var = atfork_parent_var = atfork_child_var = false;
+    singlethread_test (0);
+    TEST_VERIFY (!atfork_prepare_var);
+    TEST_VERIFY (!atfork_parent_var);
+    TEST_VERIFY (!atfork_child_var);
+  }
+
+  /* With PIDFD_FORK_RUNATFORK, pidfd_fork acts as fork.  */
+  {
+    atfork_prepare_var = atfork_parent_var = atfork_child_var = false;
+    pthread_atfork (atfork_prepare, atfork_parent, atfork_child);
+    singlethread_test (PIDFDFORK_RUNATFORK);
+    TEST_VERIFY (atfork_prepare_var);
+    TEST_VERIFY (atfork_parent_var);
+    TEST_VERIFY (!atfork_child_var);
+  }
+
+  return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index b7422d5747..045205de0c 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -2574,6 +2574,7 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F
 GLIBC_2.4 __confstr_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 90680bc1d7..5a67604948 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2680,5 +2680,6 @@  GLIBC_2.38 __isoc23_wcstoull F
 GLIBC_2.38 __isoc23_wcstoull_l F
 GLIBC_2.38 __isoc23_wcstoumax F
 GLIBC_2.38 __isoc23_wscanf F
+GLIBC_2.38 pidfd_fork F
 GLIBC_2.38 pidfd_spawn F
 GLIBC_2.38 pidfd_spawnp F