diff --git a/cfgwriter.c b/cfgwriter.c
index 43a9539..30df430 100644
--- a/cfgwriter.c
+++ b/cfgwriter.c
@@ -1,13 +1,8 @@
 #include <stdio.h>
 #include <string.h>
+#include "config.h"
 #include "simple-protobuf/simple_protobuf.h"
 
-struct CONFIG {
-    char pwd[64];  //password
-    char sps[64];  //set password
-};
-typedef struct CONFIG CONFIG;
-
 CONFIG cfg;
 
 int main() {
@@ -19,13 +14,14 @@ int main() {
     FILE* fp = fopen("cfg.sp", "wb");
     if(fp) {
         set_pb(fp, types_len, sizeof(CONFIG), &cfg);
-        memset(&cfg, 0, sizeof(CONFIG));
         fclose(fp);
-        puts("Write file succeed.");
+        puts("Config is saved to cfg.sp.");
         fp = NULL;
+        puts("Check config...");
         fp = fopen("cfg.sp", "rb");
         if(fp) {
             SIMPLE_PB* spb = get_pb(fp);
+            memset(&cfg, 0, sizeof(CONFIG));
             memcpy(&cfg, spb->target, sizeof(CONFIG));
             printf("set pwd: %s, sps: %s\n", cfg.pwd, cfg.sps);
         } else perror("[SPB]");
diff --git a/config.h b/config.h
new file mode 100644
index 0000000..56dd421
--- /dev/null
+++ b/config.h
@@ -0,0 +1,10 @@
+#ifndef _CONFIG_H_
+#define _CONFIG_H_
+
+struct CONFIG {
+    char pwd[64];  //password
+    char sps[64];  //set password
+};
+typedef struct CONFIG CONFIG;
+
+#endif
\ No newline at end of file
diff --git a/server.c b/server.c
index 4002fff..f224456 100644
--- a/server.c
+++ b/server.c
@@ -13,18 +13,13 @@
 #include <unistd.h>
 #include <pthread.h>
 #include <time.h>
+#include "config.h"
 #include "simple-protobuf/simple_protobuf.h"
 
 #if !__APPLE__
     #include <sys/sendfile.h> 
 #endif
 
-struct CONFIG {
-    char pwd[64];  //password
-    char sps[64];  //set password
-};
-typedef struct CONFIG CONFIG;
-
 CONFIG* cfg;
 
 int fd;
@@ -250,16 +245,17 @@ int s3_set_data(THREADTIMER *timer) {
             printf("Get data size: %tu\n", timer->numbytes);
         }
     }
-    if(file_size <= BUFSIZ - (is_first_data?0:sizeof(uint32_t))) {
-        while(timer->numbytes != file_size - (is_first_data?0:sizeof(uint32_t))) {
-            timer->numbytes += recv(timer->accept_fd, timer->data + timer->numbytes + (is_first_data?0:sizeof(uint32_t)), BUFSIZ - timer->numbytes - (is_first_data?0:sizeof(uint32_t)), 0);
+    size_t offset = (is_first_data?0:sizeof(uint32_t));
+    if(file_size <= BUFSIZ - offset) {
+        while(timer->numbytes != file_size - offset) {
+            timer->numbytes += recv(timer->accept_fd, timer->data + timer->numbytes + offset, BUFSIZ - timer->numbytes - offset, 0);
         }
-        if(fwrite(timer->data + (is_first_data?0:sizeof(uint32_t)), file_size, 1, timer->fp) != 1) {
+        if(fwrite(timer->data + offset, file_size, 1, timer->fp) != 1) {
             puts("Set data error.");
             return close_file_and_send(timer, "erro", 4);
         } else return close_file_and_send(timer, "succ", 4);
     } else {
-        if(fwrite(timer->data + (is_first_data?0:sizeof(uint32_t)), timer->numbytes - (is_first_data?0:sizeof(uint32_t)), 1, timer->fp) != 1) {
+        if(fwrite(timer->data + offset, timer->numbytes - offset, 1, timer->fp) != 1) {
             puts("Set data error.");
             return close_file_and_send(timer, "erro", 4);
         }