Linux: Remove <sys/sysctl.h> and the sysctl function

Linux 5.5 remove the system call in commit
61a47c1ad3a4dc6882f01ebdc88138ac62d0df03 ("Linux: Remove
<sys/sysctl.h>").  Therefore, the compat function is just a stub that
sets ENOSYS.

Due to SHLIB_COMPAT, new ports will not add the sysctl function anymore
automatically.

x32 already lacks the sysctl function, so an empty sysctl.c file is
used to suppress it.  Otherwise, a new compat symbol would be added.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

10 files changed, 46 insertions, 124 deletions

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 60dc5cf..089a489 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -54,9 +54,7 @@ CFLAGS-malloc.c += -DMORECORE_CLEARS=2
 endif
 
 ifeq ($(subdir),misc)
-include $(firstword $(wildcard $(sysdirs:=/sysctl.mk)))
-
-sysdep_routines += adjtimex clone umount umount2 readahead \
+sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
 		   setfsuid setfsgid epoll_pwait signalfd \
 		   eventfd eventfd_read eventfd_write prlimit \
 		   personality epoll_wait tee vmsplice splice \
@@ -71,7 +69,7 @@ CFLAGS-open_by_handle_at.c = -fexceptions -fasynchronous-unwind-tables
 CFLAGS-sync_file_range.c = -fexceptions -fasynchronous-unwind-tables
 CFLAGS-tst-writev.c += "-DARTIFICIAL_LIMIT=(0x80000000-sysconf(_SC_PAGESIZE))"
 
-sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
+sysdep_headers += sys/mount.h sys/acct.h \
 		  sys/klog.h \
 		  sys/user.h sys/prctl.h \
 		  sys/kd.h sys/soundcard.h sys/vt.h \
@@ -81,7 +79,7 @@ sysdep_headers += sys/mount.h sys/acct.h sys/sysctl.h \
 		  bits/a.out.h sys/inotify.h sys/signalfd.h sys/eventfd.h \
 		  sys/timerfd.h sys/fanotify.h bits/eventfd.h bits/inotify.h \
 		  bits/signalfd.h bits/timerfd.h bits/epoll.h \
-		  bits/socket_type.h bits/syscall.h bits/sysctl.h \
+		  bits/socket_type.h bits/syscall.h \
 		  bits/mman-linux.h bits/mman-shared.h bits/ptrace-shared.h \
 		  bits/siginfo-arch.h bits/siginfo-consts-arch.h \
 		  bits/procfs.h bits/procfs-id.h bits/procfs-extra.h \
diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
index d385085..9a58dda 100644
--- a/sysdeps/unix/sysv/linux/Versions
+++ b/sysdeps/unix/sysv/linux/Versions
@@ -177,6 +177,8 @@ libc {
   GLIBC_2.30 {
     getdents64; gettid; tgkill;
   }
+  GLIBC_2.32 {
+  }
   GLIBC_PRIVATE {
     # functions used in other libraries
     __syscall_rt_sigqueueinfo;
diff --git a/sysdeps/unix/sysv/linux/bits/sysctl.h b/sysdeps/unix/sysv/linux/bits/sysctl.h
deleted file mode 100644
index 81447b2..0000000
--- a/sysdeps/unix/sysv/linux/bits/sysctl.h
+++ /dev/null
@@ -1 +0,0 @@
-/* Empty file.  */
diff --git a/sysdeps/unix/sysv/linux/x86/bits/sysctl.h b/sysdeps/unix/sysv/linux/microblaze/sysctl.c
index 873a2af..d35dd8e 100644
--- a/sysdeps/unix/sysv/linux/x86/bits/sysctl.h
+++ b/sysdeps/unix/sysv/linux/microblaze/sysctl.c
@@ -1,4 +1,5 @@
-/* Copyright (C) 2012-2020 Free Software Foundation, Inc.
+/* sysctl function stub.  microblaze 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
@@ -15,6 +16,14 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#if defined __x86_64__ && defined __ILP32__
-# error "sysctl system call is unsupported in x32 kernel"
+/* microblaze is special because it has an ABI baseline of 2.18, but
+   still includes the __sysctl symbol.  */
+
+#ifdef SHARED
+
+# include <sysdeps/unix/sysv/linux/sysctl.c>
+
+strong_alias (___sysctl, ___sysctl2)
+compat_symbol (libc, ___sysctl2, __sysctl, GLIBC_2_2);
+
 #endif
diff --git a/sysdeps/unix/sysv/linux/generic/sysctl.c b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/sysctl.c
index e7d5a3c..25203e4 100644
--- a/sysdeps/unix/sysv/linux/generic/sysctl.c
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/sysctl.c
@@ -1,6 +1,6 @@
-/* Copyright (C) 2011-2020 Free Software Foundation, Inc.
+/* sysctl function stub.  powerpc64le version.
+   Copyright (C) 2020 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
 
    The GNU C Library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
@@ -13,20 +13,17 @@
    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
+   License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
+/* powerpc64le is special because it has an ABI baseline of 2.17, but
+   still includes the __sysctl symbol.  */
 
-#include <sysdep.h>
-#include <sys/syscall.h>
+#ifdef SHARED
 
-/* This deprecated syscall is no longer used (replaced with /proc/sys).  */
-int
-sysctl (int *name, int nlen, void *oldval, size_t *oldlenp,
-        void *newval, size_t newlen)
-{
-  __set_errno (ENOSYS);
-  return -1;
-}
-stub_warning (sysctl)
+# include <sysdeps/unix/sysv/linux/sysctl.c>
+
+strong_alias (___sysctl, ___sysctl2)
+compat_symbol (libc, ___sysctl2, __sysctl, GLIBC_2_2);
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/sys/sysctl.h b/sysdeps/unix/sysv/linux/sys/sysctl.h
deleted file mode 100644
index 1ead5972..0000000
--- a/sysdeps/unix/sysv/linux/sys/sysctl.h
+++ /dev/null
@@ -1,76 +0,0 @@
-/* Copyright (C) 1996-2020 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
-   <https://www.gnu.org/licenses/>.  */
-
-#ifndef	_SYS_SYSCTL_H
-#define	_SYS_SYSCTL_H	1
-
-#warning "The <sys/sysctl.h> header is deprecated and will be removed."
-
-#include <features.h>
-#define __need_size_t
-#include <stddef.h>
-/* Prevent more kernel headers than necessary to be included.  */
-#ifndef _LINUX_KERNEL_H
-# define _LINUX_KERNEL_H	1
-# define __undef_LINUX_KERNEL_H
-#endif
-#ifndef _LINUX_TYPES_H
-# define _LINUX_TYPES_H		1
-# define __undef_LINUX_TYPES_H
-#endif
-#ifndef _LINUX_LIST_H
-# define _LINUX_LIST_H		1
-# define __undef_LINUX_LIST_H
-#endif
-#ifndef __LINUX_COMPILER_H
-# define __LINUX_COMPILER_H	1
-# define __user
-# define __undef__LINUX_COMPILER_H
-#endif
-
-#include <linux/sysctl.h>
-
-#ifdef __undef_LINUX_KERNEL_H
-# undef _LINUX_KERNEL_H
-# undef __undef_LINUX_KERNEL_H
-#endif
-#ifdef __undef_LINUX_TYPES_H
-# undef _LINUX_TYPES_H
-# undef __undef_LINUX_TYPES_H
-#endif
-#ifdef __undef_LINUX_LIST_H
-# undef _LINUX_LIST_H
-# undef __undef_LINUX_LIST_H
-#endif
-#ifdef __undef__LINUX_COMPILER_H
-# undef __LINUX_COMPILER_H
-# undef __user
-# undef __undef__LINUX_COMPILER_H
-#endif
-
-#include <bits/sysctl.h>
-
-__BEGIN_DECLS
-
-/* Read or write system parameters.  */
-extern int sysctl (int *__name, int __nlen, void *__oldval,
-		   size_t *__oldlenp, void *__newval, size_t __newlen) __THROW
-  __attribute_deprecated__;
-
-__END_DECLS
-
-#endif	/* _SYS_SYSCTL_H */
diff --git a/sysdeps/unix/sysv/linux/sysctl.c b/sysdeps/unix/sysv/linux/sysctl.c
index 5ea8be8..389b958 100644
--- a/sysdeps/unix/sysv/linux/sysctl.c
+++ b/sysdeps/unix/sysv/linux/sysctl.c
@@ -1,4 +1,4 @@
-/* Read or write system information.  Linux version.
+/* sysctl function stub.
    Copyright (C) 1996-2020 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
@@ -17,25 +17,20 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <errno.h>
-#include <linux/sysctl.h>
+#include <shlib-compat.h>
 
-#include <sysdep.h>
-#include <sys/syscall.h>
-
-int
-__sysctl (int *name, int nlen, void *oldval, size_t *oldlenp,
-	  void *newval, size_t newlen)
+#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_32)
+int attribute_compat_text_section
+___sysctl (int *name, int nlen, void *oldval, size_t *oldlenp,
+           void *newval, size_t newlen)
 {
-  struct __sysctl_args args =
-  {
-    .name = name,
-    .nlen = nlen,
-    .oldval = oldval,
-    .oldlenp = oldlenp,
-    .newval = newval,
-    .newlen = newlen
-  };
-
-  return INLINE_SYSCALL (_sysctl, 1, &args);
+  __set_errno (ENOSYS);
+  return -1;
 }
-weak_alias (__sysctl, sysctl)
+compat_symbol (libc, ___sysctl, sysctl, GLIBC_2_0);
+
+# if SHLIB_COMPAT (libc, GLIBC_2_2, GLIBC_2_17)
+strong_alias (___sysctl, ___sysctl2)
+compat_symbol (libc, ___sysctl2, __sysctl, GLIBC_2_2);
+# endif
+#endif
diff --git a/sysdeps/unix/sysv/linux/sysctl.mk b/sysdeps/unix/sysv/linux/sysctl.mk
deleted file mode 100644
index 8d04d12..0000000
--- a/sysdeps/unix/sysv/linux/sysctl.mk
+++ /dev/null
@@ -1,3 +0,0 @@
-# sysctl system call has been deprecated.  It is provided for backward
-# compatility.  New target shouldn't add it (see x86_64/x32/sysctl.mk).
-sysdep_routines += sysctl
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/sysctl.c b/sysdeps/unix/sysv/linux/x86_64/x32/sysctl.c
new file mode 100644
index 0000000..88f2f74
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/sysctl.c
@@ -0,0 +1,2 @@
+/* Despite the old base symbol version, x32 does not have a sysctl
+   function.  */
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/sysctl.mk b/sysdeps/unix/sysv/linux/x86_64/x32/sysctl.mk
deleted file mode 100644
index da018fe..0000000
--- a/sysdeps/unix/sysv/linux/x86_64/x32/sysctl.mk
+++ /dev/null
@@ -1 +0,0 @@
-# X32 doesn't support sysctl.