diff mbox series

[v3,4/4] posix: Add posix_spawn_file_actions_closefrom

Message ID 20201223163651.2634504-4-adhemerval.zanella@linaro.org
State Superseded
Headers
Series [v3,1/4] support: Add xclone |

Commit Message

Adhemerval Zanella Dec. 23, 2020, 4:36 p.m. UTC 
  Changes from previous version:

  - Fixed typos and commit wording.
  - Remove unecessary include on spawni.c.

--

This patch adds a way to close a range of file descriptors on
posix_spawn as a new file action.  The API is similar to the one
provided by Solaris 11 [1], where the file action causes the all open
file descriptors greater than or equal to input on to be closed when
the new process is spawned.

The function The function posix_spawn_file_actions_closefrom_np is safe
to be implemented by interacting over /proc/self/fd, since the Linux
spawni.c helper process does not use CLONE_FILES, so its has own file
descriptor table and any failure (in /proc operation) aborts the process
creation and returns an error to the caller.

I am aware that this file action might be redundant to the current
approach of POSIX in promoting O_CLOEXEC in more interfaces. However
O_CLOEXEC is still not the default and for some specific usages, the
caller needs to close all possible file descriptors to avoid them
leaking.  Some examples are CPython (discussed in BZ#10353) and OpenJDK
jspawnhelper [2] (where OpenJDK spawns a helper process to exactly
closes all file descriptors).  Most likely any environment which calls
functions that might open file descriptor under the hood and aim to use
posix_spawn might face the same requirement.

Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu, and
aarch64-linux-gnu.

[1] https://docs.oracle.com/cd/E36784_01/html/E36874/posix-spawn-file-actions-addclosefrom-np-3c.html
[2] https://github.com/openjdk/jdk/blob/master/src/java.base/unix/native/libjava/childproc.c#L82
---
 NEWS                                          |   5 +
 posix/Makefile                                |   4 +-
 posix/Versions                                |   3 +
 posix/spawn.h                                 |   8 +
 posix/spawn_faction_addclosefrom.c            |  57 ++++
 posix/spawn_faction_destroy.c                 |   1 +
 posix/spawn_int.h                             |   6 +
 posix/tst-spawn5.c                            | 283 ++++++++++++++++++
 sysdeps/generic/spawn_int_abi.h               |  24 ++
 sysdeps/mach/hurd/i386/libc.abilist           |   1 +
 sysdeps/mach/hurd/spawni.c                    |   4 +
 sysdeps/posix/spawni.c                        |   4 +
 sysdeps/unix/sysv/linux/aarch64/libc.abilist  |   1 +
 sysdeps/unix/sysv/linux/alpha/libc.abilist    |   1 +
 sysdeps/unix/sysv/linux/arc/libc.abilist      |   1 +
 sysdeps/unix/sysv/linux/arm/be/libc.abilist   |   1 +
 sysdeps/unix/sysv/linux/arm/le/libc.abilist   |   1 +
 sysdeps/unix/sysv/linux/csky/libc.abilist     |   1 +
 sysdeps/unix/sysv/linux/hppa/libc.abilist     |   1 +
 sysdeps/unix/sysv/linux/i386/libc.abilist     |   1 +
 sysdeps/unix/sysv/linux/ia64/libc.abilist     |   1 +
 .../sysv/linux/m68k/coldfire/libc.abilist     |   1 +
 .../unix/sysv/linux/m68k/m680x0/libc.abilist  |   1 +
 .../sysv/linux/microblaze/be/libc.abilist     |   1 +
 .../sysv/linux/microblaze/le/libc.abilist     |   1 +
 .../sysv/linux/mips/mips32/fpu/libc.abilist   |   1 +
 .../sysv/linux/mips/mips32/nofpu/libc.abilist |   1 +
 .../sysv/linux/mips/mips64/n32/libc.abilist   |   1 +
 .../sysv/linux/mips/mips64/n64/libc.abilist   |   1 +
 sysdeps/unix/sysv/linux/nios2/libc.abilist    |   1 +
 .../linux/powerpc/powerpc32/fpu/libc.abilist  |   1 +
 .../powerpc/powerpc32/nofpu/libc.abilist      |   1 +
 .../linux/powerpc/powerpc64/be/libc.abilist   |   1 +
 .../linux/powerpc/powerpc64/le/libc.abilist   |   1 +
 .../unix/sysv/linux/riscv/rv32/libc.abilist   |   1 +
 .../unix/sysv/linux/riscv/rv64/libc.abilist   |   1 +
 .../unix/sysv/linux/s390/s390-32/libc.abilist |   1 +
 .../unix/sysv/linux/s390/s390-64/libc.abilist |   1 +
 sysdeps/unix/sysv/linux/sh/be/libc.abilist    |   1 +
 sysdeps/unix/sysv/linux/sh/le/libc.abilist    |   1 +
 .../sysv/linux/sparc/sparc32/libc.abilist     |   1 +
 .../sysv/linux/sparc/sparc64/libc.abilist     |   1 +
 sysdeps/unix/sysv/linux/spawn_int_abi.h       |  25 ++
 sysdeps/unix/sysv/linux/spawni.c              |  34 ++-
 .../unix/sysv/linux/x86_64/64/libc.abilist    |   1 +
 .../unix/sysv/linux/x86_64/x32/libc.abilist   |   1 +
 46 files changed, 475 insertions(+), 16 deletions(-)
 create mode 100644 posix/spawn_faction_addclosefrom.c
 create mode 100644 posix/tst-spawn5.c
 create mode 100644 sysdeps/generic/spawn_int_abi.h
 create mode 100644 sysdeps/unix/sysv/linux/spawn_int_abi.h

Comments

Florian Weimer March 9, 2021, 10:45 a.m. UTC | #1 
* Adhemerval Zanella via Libc-alpha:

> This patch adds a way to close a range of file descriptors on
> posix_spawn as a new file action.  The API is similar to the one
> provided by Solaris 11 [1], where the file action causes the all open
> file descriptors greater than or equal to input on to be closed when
> the new process is spawned.

Commit subject should say posix_spawn_file_actions_closefrom_np.

> The function The function posix_spawn_file_actions_closefrom_np is safe
> to be implemented by interacting over /proc/self/fd, since the Linux
> spawni.c helper process does not use CLONE_FILES, so its has own file
> descriptor table and any failure (in /proc operation) aborts the process
> creation and returns an error to the caller.

Duplicate “The function”, ”iterating” instead of “interacting”.

>
> diff --git a/NEWS b/NEWS
> index e6446f0548..60a13edcbe 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -34,6 +34,11 @@ Major new features:
>    greater than given integer.  This function is a GNU extension, although it
>    also present in other systems.
>  
> +* The posix_spawn_file_actions_closefrom_np has been added, enabling
> +  posix_spawn and posix_spawnp to close all file descriptors greater than
> +  a giver integer.  This function is a GNU extension, although Solaris also
> +  provides a similar function.

Missing “function”.  “great than or equal to”.

> diff --git a/posix/Versions b/posix/Versions
> index 7d06a6d0c0..95d7b01126 100644
> --- a/posix/Versions
> +++ b/posix/Versions
> @@ -147,6 +147,9 @@ libc {
>    }
>    GLIBC_2.30 {
>    }
> +  GLIBC_2.33 {
> +    posix_spawn_file_actions_addclosefrom_np;
> +  }

Needs to be GLIBC_2.34 now.  Copyright years need adjusting as well.

> diff --git a/posix/spawn.h b/posix/spawn.h
> index be6bd591a3..e81b4a4e90 100644
> --- a/posix/spawn.h
> +++ b/posix/spawn.h
> @@ -213,6 +213,14 @@ extern int posix_spawn_file_actions_addchdir_np (posix_spawn_file_actions_t *
>  extern int posix_spawn_file_actions_addfchdir_np (posix_spawn_file_actions_t *,
>  						  int __fd)
>       __THROW __nonnull ((1));
> +
> +/* Add an action to close all file descriptor greater than FROM during
> +   spawn.  This affects the subsequent file actions.  */
> +extern int
> +posix_spawn_file_actions_addclosefrom_np (posix_spawn_file_actions_t *,
> +					  int __from)
> +     __THROW __nonnull ((1));
> +
>  #endif

Likewise, “greater than or equal to”.

> diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c
> new file mode 100644
> index 0000000000..a20e9c9ac7
> --- /dev/null
> +++ b/posix/tst-spawn5.c
> @@ -0,0 +1,283 @@

> +/* Nonzero if the program gets called via `exec'.  */
> +static int restart;

“was called”?

> +/* Hold the four initial argument used to respawn the process.  */
> +static char *initial_argv[7];

four != 7?

> +/* Called on process re-execution.  The arguments are the expected opened
> +   file descriptors.  */
> +_Noreturn static void
> +handle_restart (int argc, char *argv[])
> +{

> +      char *endptr;
> +      long int fd = strtol (e->d_name, &endptr, 10);
> +      if (*endptr != '\0' || fd < 0 || fd > INT_MAX)
> +        FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s",
> +                    e->d_name);

Maybe use strtoul here?

> +static void
> +do_test_closefrom (void)
> +{

> +  /* Close a range and add some file actions.  */
> +  {
> +    posix_spawn_file_actions_t fa;
> +    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
> +
> +    TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, lowfd + 1), 0);
> +    TEST_COMPARE (posix_spawn_file_actions_addopen (&fa, lowfd, "/dev/null",
> +						    0666, O_RDONLY), 0);
> +    TEST_COMPARE (posix_spawn_file_actions_adddup2 (&fa, lowfd, lowfd + 1), 0);
> +    TEST_COMPARE (posix_spawn_file_actions_addopen (&fa, lowfd, "/dev/null",
> +						    0666, O_RDONLY), 0);
> +
> +    spawn_closefrom_test (&fa, lowfd, lowfd, (int[]){lowfd, lowfd + 1}, 2);

I believe the closefrom should start add lowfd here, to check that the
closing is ordered with regards to the other operations.

> diff --git a/sysdeps/generic/spawn_int_abi.h b/sysdeps/generic/spawn_int_abi.h
> new file mode 100644
> index 0000000000..bfc8961598
> --- /dev/null
> +++ b/sysdeps/generic/spawn_int_abi.h
> @@ -0,0 +1,24 @@
> +/* Internal ABI specific for posix_spawn functionality.  Generic version.

> +#ifndef _SPAWN_INT_ABI_H
> +#define _SPAWN_INT_ABI_H
> +
> +#define __SPAWN_SUPPORT_CLOSEFROM 0
> +
> +#endif /* _SPAWN_INT_H */

Final comment is wrong.  The header is misnamed because the macro does
not actually impact ABI.

> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
> index f157bfffd2..ea87d8b5e6 100644
> --- a/sysdeps/unix/sysv/linux/spawni.c
> +++ b/sysdeps/unix/sysv/linux/spawni.c

>  /* The Linux implementation of posix_spawn{p} uses the clone syscall directly
>     with CLONE_VM and CLONE_VFORK flags and an allocated stack.  The new stack
> @@ -280,6 +274,14 @@ __spawni_child (void *arguments)
>  	      if (__fchdir (action->action.fchdir_action.fd) != 0)
>  		goto fail;
>  	      break;
> +
> +	    case spawn_do_closefrom:
> +	      {
> +		int lowfd = action->action.closefrom_action.from;
> +	        int r = INLINE_SYSCALL_CALL (close_range, lowfd, ~0U, 0);
> +		if (r != 0 && !__closefrom_fallback (lowfd))
> +		  goto fail;
> +	      } break;

If you implement the agressive up-to-INT_MAX closing in
__closefrom_fallback, this probably needs a flag that it disables it
when called from here.

Thanks,
Florian
Adhemerval Zanella March 9, 2021, 7:48 p.m. UTC | #2 
On 09/03/2021 07:45, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
> 
>> This patch adds a way to close a range of file descriptors on
>> posix_spawn as a new file action.  The API is similar to the one
>> provided by Solaris 11 [1], where the file action causes the all open
>> file descriptors greater than or equal to input on to be closed when
>> the new process is spawned.
> 
> Commit subject should say posix_spawn_file_actions_closefrom_np.

Ack.

> 
>> The function The function posix_spawn_file_actions_closefrom_np is safe
>> to be implemented by interacting over /proc/self/fd, since the Linux
>> spawni.c helper process does not use CLONE_FILES, so its has own file
>> descriptor table and any failure (in /proc operation) aborts the process
>> creation and returns an error to the caller.
> 
> Duplicate “The function”, ”iterating” instead of “interacting”.

Ack.

> 
>>
>> diff --git a/NEWS b/NEWS
>> index e6446f0548..60a13edcbe 100644
>> --- a/NEWS
>> +++ b/NEWS
>> @@ -34,6 +34,11 @@ Major new features:
>>    greater than given integer.  This function is a GNU extension, although it
>>    also present in other systems.
>>  
>> +* The posix_spawn_file_actions_closefrom_np has been added, enabling
>> +  posix_spawn and posix_spawnp to close all file descriptors greater than
>> +  a giver integer.  This function is a GNU extension, although Solaris also
>> +  provides a similar function.
> 
> Missing “function”.  “great than or equal to”.
> 

Ack.

>> diff --git a/posix/Versions b/posix/Versions
>> index 7d06a6d0c0..95d7b01126 100644
>> --- a/posix/Versions
>> +++ b/posix/Versions
>> @@ -147,6 +147,9 @@ libc {
>>    }
>>    GLIBC_2.30 {
>>    }
>> +  GLIBC_2.33 {
>> +    posix_spawn_file_actions_addclosefrom_np;
>> +  }
> 
> Needs to be GLIBC_2.34 now.  Copyright years need adjusting as well.

Ack.

> 
>> diff --git a/posix/spawn.h b/posix/spawn.h
>> index be6bd591a3..e81b4a4e90 100644
>> --- a/posix/spawn.h
>> +++ b/posix/spawn.h
>> @@ -213,6 +213,14 @@ extern int posix_spawn_file_actions_addchdir_np (posix_spawn_file_actions_t *
>>  extern int posix_spawn_file_actions_addfchdir_np (posix_spawn_file_actions_t *,
>>  						  int __fd)
>>       __THROW __nonnull ((1));
>> +
>> +/* Add an action to close all file descriptor greater than FROM during
>> +   spawn.  This affects the subsequent file actions.  */
>> +extern int
>> +posix_spawn_file_actions_addclosefrom_np (posix_spawn_file_actions_t *,
>> +					  int __from)
>> +     __THROW __nonnull ((1));
>> +
>>  #endif
> 
> Likewise, “greater than or equal to”.
> 

Ack.

>> diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c
>> new file mode 100644
>> index 0000000000..a20e9c9ac7
>> --- /dev/null
>> +++ b/posix/tst-spawn5.c
>> @@ -0,0 +1,283 @@
> 
>> +/* Nonzero if the program gets called via `exec'.  */
>> +static int restart;
> 
> “was called”?
> 
>> +/* Hold the four initial argument used to respawn the process.  */
>> +static char *initial_argv[7];
> 
> four != 7?

I changed to:

/* Hold the four initial argument used to respawn the process, plus                                   
   the extra '--direct' and '--restart', and a final NULL.  */  

> 
>> +/* Called on process re-execution.  The arguments are the expected opened
>> +   file descriptors.  */
>> +_Noreturn static void
>> +handle_restart (int argc, char *argv[])
>> +{
> 
>> +      char *endptr;
>> +      long int fd = strtol (e->d_name, &endptr, 10);
>> +      if (*endptr != '\0' || fd < 0 || fd > INT_MAX)
>> +        FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s",
>> +                    e->d_name);
> 
> Maybe use strtoul here?

Ack.

> 
>> +static void
>> +do_test_closefrom (void)
>> +{
> 
>> +  /* Close a range and add some file actions.  */
>> +  {
>> +    posix_spawn_file_actions_t fa;
>> +    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
>> +
>> +    TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, lowfd + 1), 0);
>> +    TEST_COMPARE (posix_spawn_file_actions_addopen (&fa, lowfd, "/dev/null",
>> +						    0666, O_RDONLY), 0);
>> +    TEST_COMPARE (posix_spawn_file_actions_adddup2 (&fa, lowfd, lowfd + 1), 0);
>> +    TEST_COMPARE (posix_spawn_file_actions_addopen (&fa, lowfd, "/dev/null",
>> +						    0666, O_RDONLY), 0);
>> +
>> +    spawn_closefrom_test (&fa, lowfd, lowfd, (int[]){lowfd, lowfd + 1}, 2);
> 
> I believe the closefrom should start add lowfd here, to check that the
> closing is ordered with regards to the other operations.

It is already doing in, doesn't it? The {lowfd, lowfd+1} only exists if closefrom
is ordered regarding addopen and adddup2.

> 
>> diff --git a/sysdeps/generic/spawn_int_abi.h b/sysdeps/generic/spawn_int_abi.h
>> new file mode 100644
>> index 0000000000..bfc8961598
>> --- /dev/null
>> +++ b/sysdeps/generic/spawn_int_abi.h
>> @@ -0,0 +1,24 @@
>> +/* Internal ABI specific for posix_spawn functionality.  Generic version.
> 
>> +#ifndef _SPAWN_INT_ABI_H
>> +#define _SPAWN_INT_ABI_H
>> +
>> +#define __SPAWN_SUPPORT_CLOSEFROM 0
>> +
>> +#endif /* _SPAWN_INT_H */
> 
> Final comment is wrong.  The header is misnamed because the macro does
> not actually impact ABI.

I renamed to spawn_int_def.h.

> 
>> diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
>> index f157bfffd2..ea87d8b5e6 100644
>> --- a/sysdeps/unix/sysv/linux/spawni.c
>> +++ b/sysdeps/unix/sysv/linux/spawni.c
> 
>>  /* The Linux implementation of posix_spawn{p} uses the clone syscall directly
>>     with CLONE_VM and CLONE_VFORK flags and an allocated stack.  The new stack
>> @@ -280,6 +274,14 @@ __spawni_child (void *arguments)
>>  	      if (__fchdir (action->action.fchdir_action.fd) != 0)
>>  		goto fail;
>>  	      break;
>> +
>> +	    case spawn_do_closefrom:
>> +	      {
>> +		int lowfd = action->action.closefrom_action.from;
>> +	        int r = INLINE_SYSCALL_CALL (close_range, lowfd, ~0U, 0);
>> +		if (r != 0 && !__closefrom_fallback (lowfd))
>> +		  goto fail;
>> +	      } break;
> 
> If you implement the agressive up-to-INT_MAX closing in
> __closefrom_fallback, this probably needs a flag that it disables it
> when called from here.

Ack, although I do not see much gain since it should be a fallback to
a fallback.
Florian Weimer March 9, 2021, 8 p.m. UTC | #3 
* Adhemerval Zanella:

>> I believe the closefrom should start add lowfd here, to check that the
>> closing is ordered with regards to the other operations.
>
> It is already doing in, doesn't it? The {lowfd, lowfd+1} only exists
> if closefrom is ordered regarding addopen and adddup2.

Okay, fair enough.  I would have expected that the closefrom call would
be in the middle of the action list.

>> If you implement the agressive up-to-INT_MAX closing in
>> __closefrom_fallback, this probably needs a flag that it disables it
>> when called from here.
>
> Ack, although I do not see much gain since it should be a fallback to
> a fallback.

Oh, I think we should fail if the open of /proc/self/fd fails.  There is
no reason to try very hard to avoid process termination.

Thanks,
Florian
Adhemerval Zanella March 9, 2021, 8:04 p.m. UTC | #4 
On 09/03/2021 17:00, Florian Weimer wrote:
> * Adhemerval Zanella:
> 
>>> I believe the closefrom should start add lowfd here, to check that the
>>> closing is ordered with regards to the other operations.
>>
>> It is already doing in, doesn't it? The {lowfd, lowfd+1} only exists
>> if closefrom is ordered regarding addopen and adddup2.
> 
> Okay, fair enough.  I would have expected that the closefrom call would
> be in the middle of the action list.
> 
>>> If you implement the agressive up-to-INT_MAX closing in
>>> __closefrom_fallback, this probably needs a flag that it disables it
>>> when called from here.
>>
>> Ack, although I do not see much gain since it should be a fallback to
>> a fallback.
> 
> Oh, I think we should fail if the open of /proc/self/fd fails.  There is
> no reason to try very hard to avoid process termination.

Alright.
diff mbox series

Patch

diff --git a/NEWS b/NEWS
index e6446f0548..60a13edcbe 100644
--- a/NEWS
+++ b/NEWS
@@ -34,6 +34,11 @@  Major new features:
   greater than given integer.  This function is a GNU extension, although it
   also present in other systems.
 
+* The posix_spawn_file_actions_closefrom_np has been added, enabling
+  posix_spawn and posix_spawnp to close all file descriptors greater than
+  a giver integer.  This function is a GNU extension, although Solaris also
+  provides a similar function.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
 * The mallinfo function is marked deprecated.  Callers should call
diff --git a/posix/Makefile b/posix/Makefile
index 4bfc8d942c..d40636547e 100644
--- a/posix/Makefile
+++ b/posix/Makefile
@@ -57,6 +57,7 @@  routines :=								      \
 	spawn_faction_init spawn_faction_destroy spawn_faction_addclose	      \
 	spawn_faction_addopen spawn_faction_adddup2 spawn_valid_fd	      \
 	spawn_faction_addchdir spawn_faction_addfchdir			      \
+	spawn_faction_addclosefrom					      \
 	spawnattr_init spawnattr_destroy				      \
 	spawnattr_getdefault spawnattr_setdefault			      \
 	spawnattr_getflags spawnattr_setflags				      \
@@ -102,7 +103,7 @@  tests		:= test-errno tstgetopt testfnm runtests runptests \
 		   tst-sysconf-empty-chroot tst-glob_symlinks tst-fexecve \
 		   tst-glob-tilde test-ssize-max tst-spawn4 bug-regex37 \
 		   bug-regex38 tst-regcomp-truncated tst-spawn-chdir \
-		   tst-wordexp-nocmd
+		   tst-wordexp-nocmd tst-spawn5
 tests-internal	:= bug-regex5 bug-regex20 bug-regex33 \
 		   tst-rfc3484 tst-rfc3484-2 tst-rfc3484-3 \
 		   tst-glob_lstat_compat tst-spawn4-compat
@@ -258,6 +259,7 @@  tst-exec-static-ARGS = $(tst-exec-ARGS)
 tst-execvpe5-ARGS = -- $(host-test-program-cmd)
 tst-spawn-ARGS = -- $(host-test-program-cmd)
 tst-spawn-static-ARGS = $(tst-spawn-ARGS)
+tst-spawn5-ARGS = -- $(host-test-program-cmd)
 tst-dir-ARGS = `pwd` `cd $(common-objdir)/$(subdir); pwd` `cd $(common-objdir); pwd` $(objpfx)tst-dir
 tst-chmod-ARGS = $(objdir)
 tst-vfork3-ARGS = --test-dir=$(objpfx)
diff --git a/posix/Versions b/posix/Versions
index 7d06a6d0c0..95d7b01126 100644
--- a/posix/Versions
+++ b/posix/Versions
@@ -147,6 +147,9 @@  libc {
   }
   GLIBC_2.30 {
   }
+  GLIBC_2.33 {
+    posix_spawn_file_actions_addclosefrom_np;
+  }
   GLIBC_PRIVATE {
     __libc_fork; __libc_pread; __libc_pwrite;
     __nanosleep_nocancel; __pause_nocancel;
diff --git a/posix/spawn.h b/posix/spawn.h
index be6bd591a3..e81b4a4e90 100644
--- a/posix/spawn.h
+++ b/posix/spawn.h
@@ -213,6 +213,14 @@  extern int posix_spawn_file_actions_addchdir_np (posix_spawn_file_actions_t *
 extern int posix_spawn_file_actions_addfchdir_np (posix_spawn_file_actions_t *,
 						  int __fd)
      __THROW __nonnull ((1));
+
+/* Add an action to close all file descriptor greater than FROM during
+   spawn.  This affects the subsequent file actions.  */
+extern int
+posix_spawn_file_actions_addclosefrom_np (posix_spawn_file_actions_t *,
+					  int __from)
+     __THROW __nonnull ((1));
+
 #endif
 
 __END_DECLS
diff --git a/posix/spawn_faction_addclosefrom.c b/posix/spawn_faction_addclosefrom.c
new file mode 100644
index 0000000000..3b5e73fe32
--- /dev/null
+++ b/posix/spawn_faction_addclosefrom.c
@@ -0,0 +1,57 @@ 
+/* Add a closefrom to a file action list for posix_spawn.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <spawn.h>
+#include <unistd.h>
+#include <spawn_int.h>
+
+int
+__posix_spawn_file_actions_addclosefrom (posix_spawn_file_actions_t
+					 *file_actions, int from)
+{
+#if __SPAWN_SUPPORT_CLOSEFROM
+  struct __spawn_action *rec;
+
+  if (!__spawn_valid_fd (from))
+    return EBADF;
+
+  /* Allocate more memory if needed.  */
+  if (file_actions->__used == file_actions->__allocated
+      && __posix_spawn_file_actions_realloc (file_actions) != 0)
+    /* This can only mean we ran out of memory.  */
+    return ENOMEM;
+
+  /* Add the new value.  */
+  rec = &file_actions->__actions[file_actions->__used];
+  rec->tag = spawn_do_closefrom;
+  rec->action.closefrom_action.from = from;
+
+  /* Account for the new entry.  */
+  ++file_actions->__used;
+
+  return 0;
+#else
+  return EINVAL;
+#endif
+}
+weak_alias (__posix_spawn_file_actions_addclosefrom,
+	    posix_spawn_file_actions_addclosefrom_np)
+#if !__SPAWN_SUPPORT_CLOSEFROM
+stub_warning (posix_spawn_file_actions_addclosefrom_np)
+#endif
diff --git a/posix/spawn_faction_destroy.c b/posix/spawn_faction_destroy.c
index 098385e1e0..33045e2c7f 100644
--- a/posix/spawn_faction_destroy.c
+++ b/posix/spawn_faction_destroy.c
@@ -39,6 +39,7 @@  __posix_spawn_file_actions_destroy (posix_spawn_file_actions_t *file_actions)
 	case spawn_do_close:
 	case spawn_do_dup2:
 	case spawn_do_fchdir:
+	case spawn_do_closefrom:
 	  /* No cleanup required.  */
 	  break;
 	}
diff --git a/posix/spawn_int.h b/posix/spawn_int.h
index 9be54c0416..512dcea0da 100644
--- a/posix/spawn_int.h
+++ b/posix/spawn_int.h
@@ -20,6 +20,7 @@ 
 #define _SPAWN_INT_H
 
 #include <spawn.h>
+#include <spawn_int_abi.h>
 #include <stdbool.h>
 
 /* Data structure to contain the action information.  */
@@ -32,6 +33,7 @@  struct __spawn_action
     spawn_do_open,
     spawn_do_chdir,
     spawn_do_fchdir,
+    spawn_do_closefrom,
   } tag;
 
   union
@@ -60,6 +62,10 @@  struct __spawn_action
     {
       int fd;
     } fchdir_action;
+    struct
+    {
+      int from;
+    } closefrom_action;
   } action;
 };
 
diff --git a/posix/tst-spawn5.c b/posix/tst-spawn5.c
new file mode 100644
index 0000000000..a20e9c9ac7
--- /dev/null
+++ b/posix/tst-spawn5.c
@@ -0,0 +1,283 @@ 
+/* Tests for posix_spawn signal handling.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <getopt.h>
+#include <spawn.h>
+#include <fcntl.h>
+#include <sys/wait.h>
+#include <dirent.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <limits.h>
+
+#include <support/check.h>
+#include <support/xunistd.h>
+#include <support/support.h>
+
+#include <arch-fd_to_filename.h>
+#include <array_length.h>
+
+/* Nonzero if the program gets called via `exec'.  */
+static int restart;
+
+/* Hold the four initial argument used to respawn the process.  */
+static char *initial_argv[7];
+
+#define CMDLINE_OPTIONS \
+  { "restart", no_argument, &restart, 1 },
+
+#define NFDS 100
+
+static int
+open_multiple_temp_files (void)
+{
+  /* Check if the temporary file descriptor has no no gaps.  */
+  int lowfd = xopen ("/dev/null", O_RDONLY, 0600);
+  for (int i = 1; i <= NFDS; i++)
+    TEST_COMPARE (xopen ("/dev/null", O_RDONLY, 0600),
+		  lowfd + i);
+  return lowfd;
+}
+
+/* Called on process re-execution.  The arguments are the expected opened
+   file descriptors.  */
+_Noreturn static void
+handle_restart (int argc, char *argv[])
+{
+  size_t nfds = argc > 1 ? argc - 1 : 0;
+  struct fd_t
+  {
+    int fd;
+    _Bool found;
+  } *fds = xmalloc (sizeof (struct fd_t) * nfds);
+  for (int i = 0; i < nfds; i++)
+    {
+      char *endptr;
+      long int fd = strtol (argv[i+1], &endptr, 10);
+      if (*endptr != '\0' || fd < 0 || fd > INT_MAX)
+        FAIL_EXIT1 ("readdir: invalid file descriptor value: %s", argv[i]);
+
+      fds[i].fd = fd;
+      fds[i].found = false;
+    }
+
+  DIR *dirp = opendir (FD_TO_FILENAME_PREFIX);
+  if (dirp == NULL)
+    FAIL_EXIT1 ("opendir (\"" FD_TO_FILENAME_PREFIX "\"): %m");
+
+  while (true)
+    {
+      errno = 0;
+      struct dirent64 *e = readdir64 (dirp);
+      if (e == NULL)
+        {
+          if (errno != 0)
+            FAIL_EXIT1 ("readdir: %m");
+          break;
+        }
+
+      if (e->d_name[0] == '.')
+        continue;
+
+      char *endptr;
+      long int fd = strtol (e->d_name, &endptr, 10);
+      if (*endptr != '\0' || fd < 0 || fd > INT_MAX)
+        FAIL_EXIT1 ("readdir: invalid file descriptor name: /proc/self/fd/%s",
+                    e->d_name);
+
+      /* Skip the descriptor which is used to enumerate the descriptors.  */
+      if (fd == dirfd (dirp)
+          || fd == STDIN_FILENO
+	  || fd == STDOUT_FILENO
+	  || fd == STDERR_FILENO)
+        continue;
+
+      bool found = false;
+      for (int i = 0; i < nfds; i++)
+	if (fds[i].fd == fd)
+	  fds[i].found = found = true;
+
+      if (!found)
+        FAIL_EXIT1 ("unexpected open file descriptor: %ld", fd);
+    }
+  closedir (dirp);
+
+  for (int i = 0; i < nfds; i++)
+    if (!fds[i].found)
+      FAIL_EXIT1 ("file descriptor %d not opened", fds[i].fd);
+
+  free (fds);
+
+  exit (EXIT_SUCCESS);
+}
+
+static void
+spawn_closefrom_test (posix_spawn_file_actions_t *fa, int lowfd, int highfd,
+		      int *extrafds, size_t nextrafds)
+{
+  /* 6 elements from initial_argv (path to ld.so, '--library-path', the
+     path', application name', '--direct', and '--restart'), up to
+     2 * maximum_fd arguments (the expected open file descriptors), plus
+     NULL.  */
+  enum { argv_size = array_length (initial_argv) + 2 * NFDS + 1 };
+  char *args[argv_size];
+  int argc = 0;
+
+  for (char **arg = initial_argv; *arg != NULL; arg++)
+    args[argc++] = *arg;
+
+  for (int i = lowfd; i < highfd; i++)
+    args[argc++] = xasprintf ("%d", i);
+
+  for (int i = 0; i < nextrafds; i++)
+    args[argc++] = xasprintf ("%d", extrafds[i]);
+
+  args[argc] = NULL;
+  TEST_VERIFY (argc < argv_size);
+
+  pid_t pid;
+  int status;
+
+  TEST_COMPARE (posix_spawn (&pid, args[0], fa, NULL, args, environ), 0);
+  TEST_COMPARE (xwaitpid (pid, &status, 0), pid);
+  TEST_VERIFY (WIFEXITED (status));
+  TEST_VERIFY (!WIFSIGNALED (status));
+  TEST_COMPARE (WEXITSTATUS (status), 0);
+}
+
+static void
+do_test_closefrom (void)
+{
+  int lowfd = open_multiple_temp_files ();
+  const int half_fd = lowfd + NFDS / 2;
+
+  /* Close half of the descriptors and check result.  */
+  {
+    posix_spawn_file_actions_t fa;
+    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
+
+    int ret = posix_spawn_file_actions_addclosefrom_np (&fa, half_fd);
+    if (ret == EINVAL)
+      /* Hurd currently does not support closefrom fileaction.  */
+      FAIL_UNSUPPORTED ("posix_spawn_file_actions_addclosefrom_np unsupported");
+    TEST_COMPARE (ret, 0);
+
+    spawn_closefrom_test (&fa, lowfd, half_fd, NULL, 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_destroy (&fa), 0);
+  }
+
+  /* Create some gaps, close up to a threshold, and check result.  */
+  xclose (lowfd + 57);
+  xclose (lowfd + 78);
+  xclose (lowfd + 81);
+  xclose (lowfd + 82);
+  xclose (lowfd + 84);
+  xclose (lowfd + 90);
+
+  {
+    posix_spawn_file_actions_t fa;
+    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, half_fd), 0);
+
+    spawn_closefrom_test (&fa, lowfd, half_fd, NULL, 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_destroy (&fa), 0);
+  }
+
+  /* Close the remaining but the last one.  */
+  {
+    posix_spawn_file_actions_t fa;
+    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, lowfd + 1), 0);
+
+    spawn_closefrom_test (&fa, lowfd, lowfd + 1, NULL, 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_destroy (&fa), 0);
+  }
+
+  /* Close everything.  */
+  {
+    posix_spawn_file_actions_t fa;
+    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, lowfd), 0);
+
+    spawn_closefrom_test (&fa, lowfd, lowfd, NULL, 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_destroy (&fa), 0);
+  }
+
+  /* Close a range and add some file actions.  */
+  {
+    posix_spawn_file_actions_t fa;
+    TEST_COMPARE (posix_spawn_file_actions_init (&fa), 0);
+
+    TEST_COMPARE (posix_spawn_file_actions_addclosefrom_np (&fa, lowfd + 1), 0);
+    TEST_COMPARE (posix_spawn_file_actions_addopen (&fa, lowfd, "/dev/null",
+						    0666, O_RDONLY), 0);
+    TEST_COMPARE (posix_spawn_file_actions_adddup2 (&fa, lowfd, lowfd + 1), 0);
+    TEST_COMPARE (posix_spawn_file_actions_addopen (&fa, lowfd, "/dev/null",
+						    0666, O_RDONLY), 0);
+
+    spawn_closefrom_test (&fa, lowfd, lowfd, (int[]){lowfd, lowfd + 1}, 2);
+
+    TEST_COMPARE (posix_spawn_file_actions_destroy (&fa), 0);
+  }
+}
+
+static int
+do_test (int argc, char *argv[])
+{
+  /* We must have either:
+
+     - one or four parameters if called initially:
+       + argv[1]: path for ld.so        optional
+       + argv[2]: "--library-path"      optional
+       + argv[3]: the library path      optional
+       + argv[4]: the application name
+
+     - six parameters left if called through re-execution:
+       + argv[1]: the application name
+       + argv[2]: first expected open file descriptor
+       + argv[n]: last expected open file descritptor
+
+     * When built with --enable-hardcoded-path-in-tests or issued without
+       using the loader directly.  */
+
+  if (restart)
+    handle_restart (argc, argv);
+
+  initial_argv[0] = argv[1]; /* path for ld.so  */
+  initial_argv[1] = argv[2]; /* "--library-path"  */
+  initial_argv[2] = argv[3]; /* the library path  */
+  initial_argv[3] = argv[4]; /* the application name  */
+  initial_argv[4] = (char *) "--direct";
+  initial_argv[5] = (char *) "--restart";
+
+  do_test_closefrom ();
+
+  return 0;
+}
+
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>
diff --git a/sysdeps/generic/spawn_int_abi.h b/sysdeps/generic/spawn_int_abi.h
new file mode 100644
index 0000000000..bfc8961598
--- /dev/null
+++ b/sysdeps/generic/spawn_int_abi.h
@@ -0,0 +1,24 @@ 
+/* Internal ABI specific for posix_spawn functionality.  Generic version.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SPAWN_INT_ABI_H
+#define _SPAWN_INT_ABI_H
+
+#define __SPAWN_SUPPORT_CLOSEFROM 0
+
+#endif /* _SPAWN_INT_H */
diff --git a/sysdeps/mach/hurd/i386/libc.abilist b/sysdeps/mach/hurd/i386/libc.abilist
index fce67cf3ca..5b23d62b5d 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -2201,6 +2201,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/mach/hurd/spawni.c b/sysdeps/mach/hurd/spawni.c
index 178b271e4e..9ea4fc972f 100644
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -600,6 +600,10 @@  __spawni (pid_t *pid, const char *file,
 	  case spawn_do_fchdir:
 	    err = child_fchdir (action->action.fchdir_action.fd);
 	    break;
+
+	  case spawn_do_closefrom:
+	    err = EINVAL;
+	    break;
 	  }
 
 	if (err)
diff --git a/sysdeps/posix/spawni.c b/sysdeps/posix/spawni.c
index 943a598771..d05d2c8520 100644
--- a/sysdeps/posix/spawni.c
+++ b/sysdeps/posix/spawni.c
@@ -231,6 +231,10 @@  __spawni_child (void *arguments)
 	      if (__fchdir (action->action.fchdir_action.fd) != 0)
 		goto fail;
 	      break;
+
+	    case spawn_do_closefrom:
+	      __set_errno (EINVAL);
+	      goto fail;
 	    }
 	}
     }
diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
index 811d3b3cd9..65d5c3cee4 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2171,5 +2171,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index d0bc011811..ac55ceba70 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2253,6 +2253,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 c4e26b3cf6..24e623875d 100644
--- a/sysdeps/unix/sysv/linux/arc/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arc/libc.abilist
@@ -1931,5 +1931,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
index 5ccd1fb07f..50086104ea 100644
--- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
@@ -154,6 +154,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 5043e483b8..a4ebfccc74 100644
--- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
@@ -152,6 +152,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 6f3718cd14..4b45f0a8a0 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2115,5 +2115,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index 84b474dba4..b574604263 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2074,6 +2074,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 4c1399102e..51795cd925 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2240,6 +2240,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 9fcaa40c34..bafbc98f69 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2106,6 +2106,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index ccb780d9c7..8c3fc11399 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -155,6 +155,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 3afaa1c70e..10a11773f2 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2186,6 +2186,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 266063d0e8..e908a7a19a 100644
--- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
@@ -2166,5 +2166,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
index 5d893ec4d1..d8f3ff6dec 100644
--- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
@@ -2162,5 +2162,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
index 6207a15a09..1c41ce7c83 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
@@ -2157,6 +2157,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 860e5fecfa..dcec226837 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
@@ -2154,6 +2154,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 daed5ae2a8..022a7ec721 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
@@ -2163,6 +2163,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 7b6edfe8f5..a312612703 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
@@ -2157,6 +2157,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 9dd7d64500..d4e4096a11 100644
--- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
@@ -2204,5 +2204,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
index c561e5cf36..01705658c0 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
@@ -2213,6 +2213,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 d25bf75ed3..eea881eeae 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
@@ -2245,6 +2245,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 248fab8212..bb346370ad 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
@@ -2076,6 +2076,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 d02fa6b3d2..0dad53bc80 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
@@ -2366,5 +2366,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
index 56d1a16b2a..7ee1f2e189 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist
@@ -1304,6 +1304,7 @@  GLIBC_2.33 posix_openpt F
 GLIBC_2.33 posix_spawn F
 GLIBC_2.33 posix_spawn_file_actions_addchdir_np F
 GLIBC_2.33 posix_spawn_file_actions_addclose F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 posix_spawn_file_actions_adddup2 F
 GLIBC_2.33 posix_spawn_file_actions_addfchdir_np F
 GLIBC_2.33 posix_spawn_file_actions_addopen F
diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
index 8fcd329728..51fc25677d 100644
--- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
@@ -2133,5 +2133,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
index b06cc94710..61bda38fb0 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
@@ -2211,6 +2211,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 6ede1579ca..a73bc16ae0 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
@@ -2112,6 +2112,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 0f426028a1..974090f39b 100644
--- a/sysdeps/unix/sysv/linux/sh/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/be/libc.abilist
@@ -2080,6 +2080,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 8637b683d6..910c8e752d 100644
--- a/sysdeps/unix/sysv/linux/sh/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sh/le/libc.abilist
@@ -2078,6 +2078,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 dc7c01f734..fabbdaeef0 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
@@ -2202,6 +2202,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 67d361c881..0ad7f0b18c 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
@@ -2129,6 +2129,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F
 GLIBC_2.4 __confstr_chk F
diff --git a/sysdeps/unix/sysv/linux/spawn_int_abi.h b/sysdeps/unix/sysv/linux/spawn_int_abi.h
new file mode 100644
index 0000000000..84b31104c5
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/spawn_int_abi.h
@@ -0,0 +1,25 @@ 
+/* Internal ABI specific for posix_spawn functionality.  Linux version.
+   Copyright (C) 2020 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SPAWN_INT_ABI_H
+#define _SPAWN_INT_ABI_H
+
+/* spawni.c implements closefrom by interacting over /proc/self/fd.  */
+#define __SPAWN_SUPPORT_CLOSEFROM 1
+
+#endif /* _SPAWN_INT_H */
diff --git a/sysdeps/unix/sysv/linux/spawni.c b/sysdeps/unix/sysv/linux/spawni.c
index f157bfffd2..ea87d8b5e6 100644
--- a/sysdeps/unix/sysv/linux/spawni.c
+++ b/sysdeps/unix/sysv/linux/spawni.c
@@ -16,22 +16,16 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <spawn.h>
-#include <fcntl.h>
-#include <paths.h>
-#include <string.h>
-#include <sys/resource.h>
-#include <sys/wait.h>
-#include <sys/param.h>
-#include <sys/mman.h>
-#include <not-cancel.h>
+#include <internal-signals.h>
+#include <ldsodefs.h>
 #include <local-setxid.h>
+#include <not-cancel.h>
+#include <paths.h>
 #include <shlib-compat.h>
-#include <nptl/pthreadP.h>
-#include <dl-sysdep.h>
-#include <libc-pointer-arith.h>
-#include <ldsodefs.h>
-#include "spawn_int.h"
+#include <spawn.h>
+#include <spawn_int.h>
+#include <sysdep.h>
+#include <sys/resource.h>
 
 /* The Linux implementation of posix_spawn{p} uses the clone syscall directly
    with CLONE_VM and CLONE_VFORK flags and an allocated stack.  The new stack
@@ -280,6 +274,14 @@  __spawni_child (void *arguments)
 	      if (__fchdir (action->action.fchdir_action.fd) != 0)
 		goto fail;
 	      break;
+
+	    case spawn_do_closefrom:
+	      {
+		int lowfd = action->action.closefrom_action.from;
+	        int r = INLINE_SYSCALL_CALL (close_range, lowfd, ~0U, 0);
+		if (r != 0 && !__closefrom_fallback (lowfd))
+		  goto fail;
+	      } break;
 	    }
 	}
     }
@@ -344,7 +346,9 @@  __spawnix (pid_t * pid, const char *file,
   /* We need at least a few pages in case the compiler's stack checking is
      enabled.  In some configs, it is known to use at least 24KiB.  We use
      32KiB to be "safe" from anything the compiler might do.  Besides, the
-     extra pages won't actually be allocated unless they get used.  */
+     extra pages won't actually be allocated unless they get used.
+     It also acts the slack for spawn_closefrom (including MIPS64 getdents64
+     where it might use about 1k extra stack space.  */
   argv_size += (32 * 1024);
   size_t stack_size = ALIGN_UP (argv_size, GLRO(dl_pagesize));
   void *stack = __mmap (NULL, stack_size, prot,
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
index 94bb5a0fa7..c17d5d93c3 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
@@ -2087,6 +2087,7 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 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 e94ce733ab..e8ff4b7cc9 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
@@ -2184,5 +2184,6 @@  GLIBC_2.33 lstat64 F
 GLIBC_2.33 mallinfo2 F
 GLIBC_2.33 mknod F
 GLIBC_2.33 mknodat F
+GLIBC_2.33 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.33 stat F
 GLIBC_2.33 stat64 F