sysv: linux: Add 64-bit time_t variant for msgctl

To provide a y2038 safe interface a new symbol __msgctl64 is added
and __msgctl is change to call it instead (it adds some extra buffer
coping for the 32 bit time_t implementation).

Two new structures are added:

  1. kernel_msqid64_ds: used internally only on 32-bit architectures
     to issue the syscall.  A handful of architectures (hppa, i386, mips,
     powerpc32, and sparc32) require specific implementations due to
     their kernel ABI.

  2. msqid_ds64: this is only for __TIMESIZE != 64 to use along with
     the 64-bit msgctl.  It is different than the kernel struct because
     the exported 64-bit time_t might require different alignment
     depending on the architecture ABI.

So the resulting implementation does:

  1. For 64-bit architectures it assumes msqid_ds already contains
     64-bit time_t fields and will result in just the __msgctl symbol
     using the __msgctl64 code.  The msgid_ds argument is passed as-is
     to the syscall.

  2. For 32-bit architectures with default 64-bit time_t (newer ABIs
     such riscv32 or arc), it will also result in only one exported
     symbol but with the required high/low time handling.

  3. Finally for 32-bit architecture with both 32-bit and 64-bit time_t
     support we follow the already set way to provide one symbol with
     64-bit time_t support and implement the 32-bit time_t support using
     the 64-bit time_t.

     The default 32-bit symbol will allocate and copy the msqid_ds
     over multiple buffers, but this should be deprecated in favor
     of the __msgctl64 anyway.

Checked on i686-linux-gnu and x86_64-linux-gnu.  I also did some sniff
tests on powerpc, powerpc64, mips, mips64, armhf, sparcv9, and
sparc64.

Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Alistair Francis <alistair.francis@wdc.com>

2 files changed, 41 insertions, 3 deletions

diff --git a/sysdeps/unix/sysv/linux/bits/types/struct_msqid64_ds.h b/sysdeps/unix/sysv/linux/bits/types/struct_msqid64_ds.h
new file mode 100644
index 0000000000..3536c8ea62
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/bits/types/struct_msqid64_ds.h
@@ -0,0 +1,38 @@
+/* Generic implementation of the SysV message struct msqid64_ds.
+   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/>.  */
+
+#ifndef _SYS_MSG_H
+# error "Never use <bits/msq.h> directly; include <sys/msg.h> instead."
+#endif
+
+#if __TIMESIZE == 64
+# define __msqid64_ds msqid_ds
+#else
+struct __msqid64_ds
+{
+  struct ipc_perm msg_perm;	/* structure describing operation permission */
+  __time64_t msg_stime;		/* time of last msgsnd command */
+  __time64_t msg_rtime;		/* time of last msgsnd command */
+  __time64_t msg_ctime;		/* time of last change */
+  __syscall_ulong_t __msg_cbytes; /* current number of bytes on queue */
+  msgqnum_t msg_qnum;		/* number of messages currently on queue */
+  msglen_t msg_qbytes;		/* max number of bytes allowed on queue */
+  __pid_t msg_lspid;		/* pid of last msgsnd() */
+  __pid_t msg_lrpid;		/* pid of last msgrcv() */
+};
+#endif
diff --git a/sysdeps/unix/sysv/linux/bits/types/struct_msqid_ds.h b/sysdeps/unix/sysv/linux/bits/types/struct_msqid_ds.h
index 32173a7b60..43b38175ad 100644
--- a/sysdeps/unix/sysv/linux/bits/types/struct_msqid_ds.h
+++ b/sysdeps/unix/sysv/linux/bits/types/struct_msqid_ds.h
@@ -27,11 +27,11 @@ struct msqid_ds
   struct ipc_perm msg_perm;	/* structure describing operation permission */
 #if __TIMESIZE == 32
   __time_t msg_stime;		/* time of last msgsnd command */
-  unsigned long int __glibc_reserved1;
+  unsigned long int __msg_stime_high;
   __time_t msg_rtime;		/* time of last msgsnd command */
-  unsigned long int __glibc_reserved2;
+  unsigned long int __msg_rtime_high;
   __time_t msg_ctime;		/* time of last change */
-  unsigned long int __glibc_reserved3;
+  unsigned long int __msg_ctime_high;
 #else
   __time_t msg_stime;		/* time of last msgsnd command */
   __time_t msg_rtime;		/* time of last msgsnd command */