[PATCH 3/3] linux-user: Add support for 'recvmmsg_time64()'

[Filip Bozuta <Filip.Bozuta@syrmia.com>]

This patch introduces functionality for syscall:

*recvmmsg_time64

    This syscall is a 2038 safe variant for syscall:

    int recvmmsg(int sockfd, struct mmsghdr *msgvec, unsigned int vlen,
                 int flags, struct timespec *timeout)
    --receive multiple messages on a socket--
    man page: https://man7.org/linux/man-pages/man2/recvmmsg.2.html

Implementation notes:

    Function 'do_sendrecvmmsg()' in 'syscall.c' was changed with the
    addition of a new argument 'time64' which represents a flag by
    which the function knows what kind of 'struct timespec' converting
    function to call ('target_to_host_timespec() or
    'target_to_host_timespec64()'). It is 0 in case of 'TARGET_NR_recvmmsg'
    and 1 in case of 'TARGET_NR_recvmmsg_time64'.

    In 'do_socketcall()', the 'TARGET_ABI_BITS' was checked to know
    what value for 'time64' argument to pass (0 if 'TARGET_ABI_BITS == 32'
    and 1 otherwise).

Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
---
 linux-user/syscall.c | 25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 420d7e7334..ed9c2cb7ab 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -3217,7 +3217,7 @@ static abi_long do_sendrecvmsg(int fd, abi_ulong target_msg,
 
 static abi_long do_sendrecvmmsg(int fd, abi_ulong target_msgvec_addr,
                                 unsigned int vlen, unsigned int flags,
-                                abi_long timeout, int send)
+                                abi_long timeout, int time64, int send)
 {
     struct mmsghdr *host_msgvec;
     struct target_mmsghdr *target_msgvec;
@@ -3277,7 +3277,10 @@ static abi_long do_sendrecvmmsg(int fd, abi_ulong target_msgvec_addr,
             ret = get_errno(safe_sendmmsg(fd, host_msgvec, i, flags));
         } else {
             if (timeout) {
-                if (target_to_host_timespec(&ts, timeout)) {
+                if (!time64 && target_to_host_timespec(&ts, timeout)) {
+                    return -TARGET_EFAULT;
+                }
+                if (time64 && target_to_host_timespec64(&ts, timeout)) {
                     return -TARGET_EFAULT;
                 }
                 ret = get_errno(safe_recvmmsg(fd, host_msgvec, i, flags, &ts));
@@ -3619,10 +3622,14 @@ static abi_long do_socketcall(int num, abi_ulong vptr)
         return do_sendrecvmsg(a[0], a[1], a[2], 0);
     case TARGET_SYS_ACCEPT4: /* sockfd, addr, addrlen, flags */
         return do_accept4(a[0], a[1], a[2], a[3]);
-    case TARGET_SYS_RECVMMSG: /* sockfd, msgvec, vlen, timeout, flags */
-        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], a[4], 0);
+    case TARGET_SYS_RECVMMSG: /* sockfd, msgvec, vlen, flags, timeout, */
+#if TARGET_ABI_BITS == 32
+        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], a[4], 0, 0);
+#else
+        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], a[4], 1, 0);
+#endif
     case TARGET_SYS_SENDMMSG: /* sockfd, msgvec, vlen, flags */
-        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], 0, 1);
+        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], 0, 0, 1);
     default:
         qemu_log_mask(LOG_UNIMP, "Unsupported socketcall: %d\n", num);
         return -TARGET_EINVAL;
@@ -9426,11 +9433,15 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
 #endif
 #ifdef TARGET_NR_sendmmsg
     case TARGET_NR_sendmmsg:
-        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, 0, 1);
+        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, 0, 0, 1);
 #endif
 #ifdef TARGET_NR_recvmmsg
     case TARGET_NR_recvmmsg:
-        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, arg5, 0);
+        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, arg5, 0, 0);
+#endif
+#ifdef TARGET_NR_recvmmsg_time64
+    case TARGET_NR_recvmmsg_time64:
+        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, arg5, 1, 0);
 #endif
 #ifdef TARGET_NR_sendto
     case TARGET_NR_sendto:
-- 
2.25.1