bsd-user: Add target_to_host_semarray for semaphore operations

Add target_to_host_semarray() to convert target semaphore array to host
format for semctl(2) SETALL operations.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>

bsd-user/bsd-misc.c

@@ -7,6 +7,11 @@
  */
 #include "qemu/osdep.h"
 
+#define _WANT_SEMUN
+#include <sys/types.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+#include <sys/sem.h>
 #include <sys/uuid.h>
 
 #include "qemu.h"
@@ -33,3 +38,33 @@ abi_long host_to_target_uuid(abi_ulong target_addr, struct uuid *host_uuid)
     unlock_user_struct(target_uuid, target_addr, 1);
     return 0;
 }
+
+abi_long target_to_host_semarray(int semid, unsigned short **host_array,
+        abi_ulong target_addr)
+{
+    abi_long ret;
+    int nsems, i;
+    unsigned short *array;
+    union semun semun;
+    struct semid_ds semid_ds;
+
+    semun.buf = &semid_ds;
+    ret = semctl(semid, 0, IPC_STAT, semun);
+    if (ret == -1) {
+        return get_errno(ret);
+    }
+    nsems = semid_ds.sem_nsems;
+    *host_array = g_new(unsigned short, nsems);
+    array = lock_user(VERIFY_READ, target_addr,
+        nsems * sizeof(unsigned short), 1);
+    if (array == NULL) {
+        free(*host_array);
+        return -TARGET_EFAULT;
+    }
+    for (i = 0; i < nsems; i++) {
+        __get_user((*host_array)[i], array + i);
+    }
+    unlock_user(array, target_addr, 0);
+
+    return 0;
+}