Fix warning as error for V2

Change-Id: I70cfd971fda629011ba1be84fef15afea196d393
diff --git a/mbtk/libmbtk_lib_v2/common/mbtk_utils.c b/mbtk/libmbtk_lib_v2/common/mbtk_utils.c
index fe4d716..afade99 100755
--- a/mbtk/libmbtk_lib_v2/common/mbtk_utils.c
+++ b/mbtk/libmbtk_lib_v2/common/mbtk_utils.c
@@ -561,9 +561,56 @@
         }
     }
 
-    ftruncate(fd, 0);
+    if(ftruncate(fd, 0)) {
+        LOGE("ftruncate(0) fail.");
+        return -1;
+    }
+
     sprintf(buff, "%ld", (long)getpid());
-    write(fd, buff, strlen(buff) + 1);
-    return 0;
+    if(write(fd, buff, strlen(buff) + 1) == strlen(buff) + 1) {
+        return 0;
+    } else {
+        return -1;
+    }
+}
+
+void mbtk_system(const void* cmd)
+{
+    if(cmd) {
+        int ret = system(cmd);
+        if(ret == -1 || ret == 127) {
+            LOGD("system(%s) fail.", cmd);
+        }
+    }
+}
+
+void mbtk_write(int fd,const void *buf, size_t len)
+{
+    if(fd >= 0 && buf) {
+        int ret = write(fd, buf, len);
+        if(ret < 0) {
+            LOGD("write() fail:%d", errno);
+        }
+    }
+}
+
+void mbtk_read(int fd,void *buf, size_t len)
+{
+    if(fd >= 0 && buf) {
+        int ret = read(fd, buf, len);
+        if(ret < 0) {
+            LOGD("read() fail:%d", errno);
+        }
+    }
+}
+
+void mbtk_close(int fd)
+{
+    if(fd >= 0) {
+        int ret = close(fd);
+        if(ret < 0) {
+            LOGD("close() fail:%d", errno);
+        }
+    }
 }