bsd-user: Add target_to_host_msqid_ds for msgctl(2)

Add target_to_host_msqid_ds() to convert target struct msqid_ds to host
format for msgctl(2) IPC_SET operations. Uses memset to zero the struct
rather than directly accessing kernel-only members. Handles FreeBSD
64-bit time_t except on i386.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Brooks Davis <brooks@one-eyed-alien.net>
Signed-off-by: Sean Bruno <sbruno@FreeBSD.org>
Signed-off-by: Mikael Urankar <mikael.urankar@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>

bsd-user/bsd-misc.c

@@ -136,3 +136,30 @@ abi_long host_to_target_semid_ds(abi_ulong target_addr,
 
     return 0;
 }
+
+abi_long target_to_host_msqid_ds(struct msqid_ds *host_md,
+        abi_ulong target_addr)
+{
+    struct target_msqid_ds *target_md;
+
+    if (!lock_user_struct(VERIFY_READ, target_md, target_addr, 1)) {
+        return -TARGET_EFAULT;
+    }
+
+    memset(host_md, 0, sizeof(struct msqid_ds));
+    target_to_host_ipc_perm__locked(&host_md->msg_perm,
+                                    &target_md->msg_perm);
+
+    /* msg_first and msg_last are not used by IPC_SET/IPC_STAT in kernel. */
+    __get_user(host_md->msg_cbytes, &target_md->msg_cbytes);
+    __get_user(host_md->msg_qnum, &target_md->msg_qnum);
+    __get_user(host_md->msg_qbytes, &target_md->msg_qbytes);
+    __get_user(host_md->msg_lspid, &target_md->msg_lspid);
+    __get_user(host_md->msg_lrpid, &target_md->msg_lrpid);
+    __get_user(host_md->msg_stime, &target_md->msg_stime);
+    __get_user(host_md->msg_rtime, &target_md->msg_rtime);
+    __get_user(host_md->msg_ctime, &target_md->msg_ctime);
+    unlock_user_struct(target_md, target_addr, 0);
+
+    return 0;
+}