tcp传输图片（发送端使用sendfile函数）



客户端client向服务器server发送一幅图片，使用tcp传输：

 

服务器代码：

1. #include <sys/socket.h>
   
2. #include <sys/types.h>
   
3. #include <stdlib.h>
   
4. #include <stdio.h>
   
5. #include <string.h>
   
6. #include <unistd.h>
   
7. #include <error.h>
   
8. #include <netinet/in.h>
   
9. #include <arpa/inet.h>
   
10. 
    
11. #define SER_PORT 10500
    
12. #define MAX_LEN 512
    
13. 
    
14. int main(int argc,char**argv)
    
15. {
    
16.     int listensd,connectsd;
    
17.     struct sockaddr_in server;
    
18.     struct sockaddr_in client;
    
19.     char buf[MAX_LEN];
    
20.     FILE *fp;
    
21.     int i;
    
22.     char *filename = "2new.jpg ";
    
23. 
    
24.     listensd=socket(AF_INET,SOCK_STREAM,0);
    
25.     if(listensd< 0)
    
26.     {
    
27.         perror( "Creating socket failed: ");
    
28.         exit(1);
    
29.     }
    
30. 
    
31.     int opt=1;
    
32.     setsockopt(listensd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));
    
33. 
    
34.     bzero(&server,sizeof(server));
    
35.     server.sin_family = AF_INET;
    
36.     server.sin_port = htons(SER_PORT);
    
37.     server.sin_addr.s_addr= htonl(INADDR_ANY);
    
38. 
    
39.     if(bind(listensd,(struct sockaddr*)&server,sizeof(server))< 0)
    
40.     {
    
41.         perror( "Bind error. ");
    
42.         exit(1);
    
43.     }
    
44. 
    
45.     if(listen(listensd,5)==-1)
    
46.     {
    
47.         perror( "listen() error\n ");
    
48.         exit(1);
    
49.     }
    
50. 
    
51.     fp=fopen( filename,"ab");
    
52.     if(fp==NULL)
    
53.     {
    
54.         printf( "File open error!\n ");
    
55.         exit(1);
    
56.     }
    
57. 
    
58.     int rn ;
    
59.     int sin_len=sizeof(client);
    
60.     if((connectsd= accept(listensd,(struct sockaddr*)&client,&sin_len))< 0)
    
61.     {
    
62.         printf( "Can 't accept the request!\n ");
    
63.         exit(1);
    
64.     }
    
65. 
    
66.     while(1)
    
67.     {
    
68.         rn=recv(connectsd,buf,MAX_LEN,0);
    
69.         if(rn< 0)
    
70.         {
    
71.             printf( "Can 't receive file!\n ");
    
72.             exit(1);
    
73.         }
    
74. 
    
75.         buf[rn]='\0';
    
76.             
    
77.         if(rn!= 0)
    
78.         {
    
79.             fwrite(buf,1,512,fp);
    
80.             bzero(buf,sizeof(buf));     
    
81.         }
    
82.         else
    
83.         {
    
84.             printf("receive over.\n");
    
85.             break;
    
86.         }                                        
    
87.     }
    
88.     close(connectsd);
    
89.     fclose(fp);
    
90.     close(listensd);
    
91.     return 0;
    
92. }

客户端代码：

1. #include <stdio.h>
   
2. #include <sys/socket.h>
   
3. #include <stdlib.h>
   
4. #include <sys/types.h>
   
5. #include <string.h>
   
6. #include <unistd.h>
   
7. #include <netinet/in.h>
   
8. #include <arpa/inet.h>
   
9. #include <netdb.h>
   
10. #include <sys/sendfile.h>
    
11. #include <sys/ioctl.h>
    
12. #include <fcntl.h>
    
13. #include <sys/stat.h>
    
14. 
    
15. #define SER_PORT 10500
    
16. #define MAX_LEN 512
    
17. 
    
18. int main(int argc,char**argv)
    
19. {
    
20.     int sd;
    
21.     int rn;
    
22.     struct sockaddr_in client,server;
    
23.     struct hostent *h;
    
24.     int fq;
    
25.     int i;
    
26.     char ch;
    
27.     struct stat st;
    
28.     char *filename = "2.jpg";
    
29.     int len = 0;
    
30. 
    
31.     sd=socket(AF_INET,SOCK_STREAM,0);
    
32.     if(sd< 0)
    
33.     {    
    
34.         printf( "Creating socket error!\n ");
    
35.         exit(1);
    
36.     }
    
37. 
    
38.     if(argc< 2)
    
39.     {
    
40.         printf( "Not enough parameter!\n ");
    
41.         exit(1);
    
42.     }
    
43. 
    
44.     h=gethostbyname(argv[1]);
    
45.     if(h==NULL)
    
46.     {
    
47.         printf( "Can 't get hostname ");
    
48.         exit(1);
    
49.     }
    
50. 
    
51.     bzero(&server,sizeof(server));
    
52.     server.sin_family=h-> h_addrtype;
    
53.     server.sin_port=htons(SER_PORT);
    
54.     server.sin_addr = *((struct in_addr*)h-> h_addr);
    
55. 
    
56.     int opt=1;
    
57.     setsockopt(sd,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));
    
58. 
    
59.     if(connect(sd,(struct sockaddr*)&server,sizeof(server))< 0)
    
60.     {
    
61.         printf( "Connect Error!\n ");
    
62.         exit(1);
    
63.     }
    
64. 
    
65.     fq = open(filename, O_RDONLY);
    
66.     if( fq< 0 )
    
67.     {
    
68.         perror("file error");
    
69.         exit(1);
    
70.     }
    
71. 
    
72.     stat(filename,&st);//获取文件大小
    
73.     len = st.st_size;
    
74. 
    
75.     if(sendfile(sd,fq,0,len)< 0)
    
76.     {
    
77.         perror("send error");
    
78.         exit(1);
    
79.     }
    
80.     
    
81.     close(sd);
    
82.     close(fq);
    
83.     return 0;
    
84. }

图片必须与程序在同一个目录，即图片须在当前目录下，输出结果是，会在当前目录下新生成一张图片，与原图片相同