linux: Move xmknod{at} to compat symbols

It also decouple mknod{at} from xmknod{at}.  The riscv32 ABI was added
on 2.33, so it is safe to remove the old __xmknot{at} symbols and just
provide the newer mknod{at} ones.

Checked with a build for all affected ABIs. I also checked on x86_64,
i686, powerpc, powerpc64le, sparcv9, sparc64, s390, and s390x.

Reviewed-by: Lukasz Majewski <lukma@denx.de>

sysdeps/unix/sysv/linux/mknod.c

@@ -0,0 +1,28 @@
+/* Create a special or ordinary file.  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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int
+__mknod (const char *path, mode_t mode, dev_t dev)
+{
+  return __mknodat (AT_FDCWD, path, mode, dev);
+}
+libc_hidden_def (__mknod)
+weak_alias (__mknod, mknod)

sysdeps/unix/sysv/linux/mknodat.c

@@ -0,0 +1,35 @@
+/* Create a special or ordinary file.  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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <errno.h>
+
+int
+__mknodat (int fd, const char *path, mode_t mode, dev_t dev)
+{
+  /* The user-exported dev_t is 64-bit while the kernel interface is
+     32-bit.  */
+  unsigned int k_dev = dev;
+  if (k_dev != dev)
+    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
+
+  return INLINE_SYSCALL_CALL (mknodat, fd, path, mode, k_dev);
+}
+libc_hidden_def (__mknodat)
+weak_alias (__mknodat, mknodat)

sysdeps/unix/sysv/linux/riscv/rv32/libc.abilist

@@ -478,8 +478,6 @@ GLIBC_2.33 __wprintf_chk F
 GLIBC_2.33 __write F
 GLIBC_2.33 __wuflow F
 GLIBC_2.33 __wunderflow F
-GLIBC_2.33 __xmknod F
-GLIBC_2.33 __xmknodat F
 GLIBC_2.33 __xpg_basename F
 GLIBC_2.33 __xpg_sigpause F
 GLIBC_2.33 __xpg_strerror_r F

sysdeps/unix/sysv/linux/xmknod.c

@@ -17,29 +17,23 @@
    <https://www.gnu.org/licenses/>.  */
 
 #include <sys/stat.h>
-#include <sys/sysmacros.h>
 #include <fcntl.h>
-#include <sysdep.h>
+#include <errno.h>
+#include <shlib-compat.h>
 
+#if SHLIB_COMPAT(libc, GLIBC_2_0, GLIBC_2_33)
 /* Create a device file named PATH, with permission and special bits MODE
    and device number DEV (which can be constructed from major and minor
    device numbers with the `makedev' macro above).  */
 int
+attribute_compat_text_section
 __xmknod (int vers, const char *path, mode_t mode, dev_t *dev)
 {
-  unsigned long long int k_dev;
-
   if (vers != _MKNOD_VER)
     return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
 
-  /* We must convert the value to dev_t type used by the kernel.  */
-  k_dev =  (*dev) & ((1ULL << 32) - 1);
-  if (k_dev != *dev)
-    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
-
-  return INLINE_SYSCALL_CALL (mknodat, AT_FDCWD, path, mode,
-			      (unsigned int) k_dev);
+  return __mknodat (AT_FDCWD, path, mode, *dev);
 }
 
-weak_alias (__xmknod, _xmknod)
-libc_hidden_def (__xmknod)
+compat_symbol (libc, __xmknod, __xmknod, GLIBC_2_0);
+#endif

sysdeps/unix/sysv/linux/xmknodat.c

@@ -15,18 +15,11 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <string.h>
-#include <sys/types.h>
 #include <sys/stat.h>
-#include <sys/sysmacros.h>
-
-#include <sysdep.h>
-#include <sys/syscall.h>
-
+#include <errno.h>
+#include <shlib-compat.h>
 
+#if SHLIB_COMPAT(libc, GLIBC_2_4, GLIBC_2_33)
 /* Create a device file named PATH relative to FD, with permission and
    special bits MODE and device number DEV (which can be constructed
    from major and minor device numbers with the `makedev' macro above).  */
@@ -36,12 +29,8 @@ __xmknodat (int vers, int fd, const char *file, mode_t mode, dev_t *dev)
   if (vers != _MKNOD_VER)
     return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
 
-  /* We must convert the value to dev_t type used by the kernel.  */
-  unsigned long long int k_dev =  (*dev) & ((1ULL << 32) - 1);
-  if (k_dev != *dev)
-    return INLINE_SYSCALL_ERROR_RETURN_VALUE (EINVAL);
-
-  return INLINE_SYSCALL (mknodat, 4, fd, file, mode, (unsigned int) k_dev);
+  return __mknodat (fd, file, mode, *dev);
 }
 
-libc_hidden_def (__xmknodat)
+compat_symbol (libc, __xmknodat, __xmknodat, GLIBC_2_4);
+#endif