[2/3] linux-user: Fix 'recvmmsg()' implementation

Commit Message

Filip Bozuta July 31, 2020, 7:06 p.m. UTC

Syscall 'recvmmsg()' takes an argument which is of type 'struct timespec'
that represents a timeout for the receive operation. Before changes from
this patch, the timeout argument was ignored. This was probably due to
the way 'recvmmsg()' was implemented with looping over 'recvmsg()' which
doesn't have the timeout argument. This was changed with the previous
patch in this series and which is why the timeout argument should be
added accordingly.

Implementation notes:

    Function 'do_sendrecvmmsg()' was changed with the addition of a new
    argument which represents the timeout. This argument is only passed
    in case of 'TARGET_NR_recvmmsg' and for 'TARGENT_NR_sendmmsg' 0 is
    passed. Function 'do_sendrecvmmsg()' was also updated accordingly in
    'do_socketcall()' for 'TARGET_SYS_recvmmsg' and 'TARGET_SYS_sendmmsg'.

Signed-off-by: Filip Bozuta <[e-mail]>
---
 linux-user/syscall.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

Patch

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 8cbefdb561..420d7e7334 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -3217,10 +3217,11 @@  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,
-                                int send)
+                                abi_long timeout, int send)
 {
     struct mmsghdr *host_msgvec;
     struct target_mmsghdr *target_msgvec;
+    struct timespec ts;
     abi_long ret = 0;
     int num_sentrecv = 0;
     int num_iovec = 0;
@@ -3275,7 +3276,14 @@  static abi_long do_sendrecvmmsg(int fd, abi_ulong target_msgvec_addr,
         if (send) {
             ret = get_errno(safe_sendmmsg(fd, host_msgvec, i, flags));
         } else {
-            ret = get_errno(safe_recvmmsg(fd, host_msgvec, i, flags, NULL));
+            if (timeout) {
+                if (target_to_host_timespec(&ts, timeout)) {
+                    return -TARGET_EFAULT;
+                }
+                ret = get_errno(safe_recvmmsg(fd, host_msgvec, i, flags, &ts));
+            } else {
+                ret = get_errno(safe_recvmmsg(fd, host_msgvec, i, flags, NULL));
+            }
         }
     }
 
@@ -3611,10 +3619,10 @@  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, flags */
-        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], 0);
+    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_SENDMMSG: /* sockfd, msgvec, vlen, flags */
-        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], 1);
+        return do_sendrecvmmsg(a[0], a[1], a[2], a[3], 0, 1);
     default:
         qemu_log_mask(LOG_UNIMP, "Unsupported socketcall: %d\n", num);
         return -TARGET_EINVAL;
@@ -9418,11 +9426,11 @@  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, 1);
+        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, 0, 1);
 #endif
 #ifdef TARGET_NR_recvmmsg
     case TARGET_NR_recvmmsg:
-        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, 0);
+        return do_sendrecvmmsg(arg1, arg2, arg3, arg4, arg5, 0);
 #endif
 #ifdef TARGET_NR_sendto
     case TARGET_NR_sendto: