osdep: Introduce qemu_dup

And use it in qemu_dup_flags.
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NJohn Snow <jsnow@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

include/qemu/osdep.h

@@ -278,6 +278,9 @@ int qemu_madvise(void *addr, size_t len, int advice);
 
 int qemu_open(const char *name, int flags, ...);
 int qemu_close(int fd);
+#ifndef _WIN32
+int qemu_dup(int fd);
+#endif
 
 #if defined(__HAIKU__) && defined(__i386__)
 #define FMT_pid "%ld"

util/osdep.c

@@ -83,14 +83,7 @@ static int qemu_dup_flags(int fd, int flags)
     int serrno;
     int dup_flags;
 
-#ifdef F_DUPFD_CLOEXEC
-    ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
-#else
-    ret = dup(fd);
-    if (ret != -1) {
-        qemu_set_cloexec(ret);
-    }
-#endif
+    ret = qemu_dup(fd);
     if (ret == -1) {
         goto fail;
     }
@@ -129,6 +122,20 @@ fail:
     return -1;
 }
 
+int qemu_dup(int fd)
+{
+    int ret;
+#ifdef F_DUPFD_CLOEXEC
+    ret = fcntl(fd, F_DUPFD_CLOEXEC, 0);
+#else
+    ret = dup(fd);
+    if (ret != -1) {
+        qemu_set_cloexec(ret);
+    }
+#endif
+    return ret;
+}
+
 static int qemu_parse_fdset(const char *param)
 {
     return qemu_parse_fd(param);