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>

1 files changed, 15 insertions, 20 deletions

diff --git a/sysdeps/unix/sysv/linux/sysctl.c b/sysdeps/unix/sysv/linux/sysctl.c
index 5ea8be8da1..389b958226 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