posix: Add posix_spawn_file_actions_addclosefrom_np

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 posix_spawn_file_actions_addclosefrom_np is safe to be
implemented by iterating 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 and i686-linux-gnu on kernel 5.11 and 4.15.

[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

40 files changed, 116 insertions, 19 deletions

diff --git a/sysdeps/generic/spawn_int_def.h b/sysdeps/generic/spawn_int_def.h
new file mode 100644
index 0000000000..7595131f6d
--- /dev/null
+++ b/sysdeps/generic/spawn_int_def.h
@@ -0,0 +1,24 @@
+/* Internal definitions for posix_spawn functionality.  Generic version.
+   Copyright (C) 2021 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 _SPAWN_INT_DEF_H
+#define _SPAWN_INT_DEF_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 475bf2d6e9..25003cda37 100644
--- a/sysdeps/mach/hurd/i386/libc.abilist
+++ b/sysdeps/mach/hurd/i386/libc.abilist
@@ -2242,6 +2242,7 @@ GLIBC_2.34 login_tty F
 GLIBC_2.34 logout F
 GLIBC_2.34 logwtmp F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 shm_open F
 GLIBC_2.34 shm_unlink F
 GLIBC_2.34 timespec_getres F
diff --git a/sysdeps/mach/hurd/spawni.c b/sysdeps/mach/hurd/spawni.c
index b5c92365f2..e011c3b34b 100644
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -613,6 +613,10 @@ retry:
 	  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 fe3b5bb7f6..ad1858fe4e 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 5d5dc5ae57..29b2fdf8c4 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
@@ -2453,6 +2453,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
index 5f863c7d46..0cf7b93b6c 100644
--- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
@@ -2552,6 +2552,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/arc/libc.abilist b/sysdeps/unix/sysv/linux/arc/libc.abilist
index e9349e550f..419c56a9c9 100644
--- a/sysdeps/unix/sysv/linux/arc/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arc/libc.abilist
@@ -2212,6 +2212,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/arm/be/libc.abilist b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
index cdfa582b30..1e1ee96ba4 100644
--- a/sysdeps/unix/sysv/linux/arm/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/be/libc.abilist
@@ -346,6 +346,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/arm/le/libc.abilist b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
index 83bf3466da..ba69e07289 100644
--- a/sysdeps/unix/sysv/linux/arm/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/arm/le/libc.abilist
@@ -343,6 +343,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/closefrom.c b/sysdeps/unix/sysv/linux/closefrom.c
index f5d7342c2c..372896b775 100644
--- a/sysdeps/unix/sysv/linux/closefrom.c
+++ b/sysdeps/unix/sysv/linux/closefrom.c
@@ -16,6 +16,7 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <sys/param.h>
 #include <unistd.h>
@@ -29,7 +30,7 @@ __closefrom (int lowfd)
   if (r == 0)
     return;
 
-  if (!__closefrom_fallback (l))
+  if (!__closefrom_fallback (l, true))
     __fortify_fail ("closefrom failed to close a file descriptor");
 }
 weak_alias (__closefrom, closefrom)
diff --git a/sysdeps/unix/sysv/linux/closefrom_fallback.c b/sysdeps/unix/sysv/linux/closefrom_fallback.c
index 61e71d388d..9cca55653a 100644
--- a/sysdeps/unix/sysv/linux/closefrom_fallback.c
+++ b/sysdeps/unix/sysv/linux/closefrom_fallback.c
@@ -22,9 +22,11 @@
 #include <stdbool.h>
 
 /* Fallback code: iterates over /proc/self/fd, closing each file descriptor
-   that fall on the criteria.  */
+   that fall on the criteria.  If DIRFD_FALLBACK is set, a failure on
+   /proc/self/fd open will trigger a fallback that tries to close a file
+   descriptor before proceed.  */
 _Bool
-__closefrom_fallback (int from)
+__closefrom_fallback (int from, _Bool dirfd_fallback)
 {
   bool ret = false;
 
@@ -33,7 +35,7 @@ __closefrom_fallback (int from)
   if (dirfd == -1)
     {
       /* The closefrom should work even when process can't open new files.  */
-      if (errno == ENOENT)
+      if (errno == ENOENT || !dirfd_fallback)
         goto err;
 
       for (int i = from; i < INT_MAX; i++)
diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
index 705b696af0..c537c12e33 100644
--- a/sysdeps/unix/sysv/linux/csky/libc.abilist
+++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
@@ -2478,6 +2478,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
index db77e473c4..b7fa808023 100644
--- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
@@ -2431,6 +2431,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
index 126c8f68d4..7684da19c2 100644
--- a/sysdeps/unix/sysv/linux/i386/libc.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
@@ -2615,6 +2615,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
index 6ca9645d1b..10179ce016 100644
--- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
@@ -2390,6 +2390,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
index 0a5d6dea8c..af66f1d485 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
@@ -347,6 +347,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
index 11e4f01d99..578e16c17a 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
@@ -2558,6 +2558,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
index 6efe53a906..ab66ff9bc3 100644
--- a/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/be/libc.abilist
@@ -2529,6 +2529,7 @@ GLIBC_2.34 mtx_timedlock F
 GLIBC_2.34 mtx_trylock F
 GLIBC_2.34 mtx_unlock F
 GLIBC_2.34 openpty F
+GLIBC_2.34 posix_spawn_file_actions_addclosefrom_np F
 GLIBC_2.34 pthread_attr_getaffinity_np F
 GLIBC_2.34 pthread_attr_getguardsize F
 GLIBC_2.34 pthread_attr_getstack F
diff --git a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
index 3b1a49cf7f..b5b71095cc 100644
--- a/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/le/libc.abilist
@@ -2526,6 +2526,7 @@ GLIBC_2.3