Ich versuche TCP-Dateiübertragung unter Linux. Nach dem Verbindungsaufbau sollte der Server "send.txt" an den Client senden und der Client erhält die Datei und speichert sie als "receive.txt". Dann bricht die Verbindung ab.Dateiübertragung mit TCP unter Linux
Die korrekte Eingabe und Ausgabe sollte sein:
Server-Terminal:
$./server &
[server] obtain socket descriptor successfully.
[server] bind tcp port 5000 in addr 0.0.0.0 successfully.
[server] listening the port 5000 successfully.
[server] server has got connect from 127.0.0.1.
[server] send send.txt to the client…ok!
[server] connection closed.
Client-Terminal:
$./client
[client] connected to server at port 5000…ok!
[client] receive file sent by server to receive.txt…ok!
[client] connection lost.
Und sowohl der Server als auch Client sollte nach dem Prozess beenden.
Aber was ich jetzt habe gibt
$ ./server &
[server] obtain socket descriptor successfully.
[server] bind tcp port 5000 in addr 0.0.0.0 sucessfully.
[server] listening the port 5000 sucessfully.
[server] server has got connect from 127.0.0.1.
[server] send send.txt to the client...ok!
[server] connection closed.
/*Here the server doesn't exit*/
$ ./client
[client] connected to server at port 5000...ok!
/*Here the client doesn't exit*/
Auch ein LEER „receive.txt“ erzeugt wird.
Mein Code wurde zuerst geschrieben, um einfache Zeichenfolgen zu übertragen, und es funktionierte korrekt. Also ich schätze das Problem liegt im Dateiübertragungsteil.
Mein Code ist wie folgt:
server.c
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <sys/socket.h>
#define PORT 5000 // The port which is communicate with server
#define BACKLOG 10
#define LENGTH 512 // Buffer length
int main()
{
int sockfd; // Socket file descriptor
int nsockfd; // New Socket file descriptor
int num;
int sin_size; // to store struct size
struct sockaddr_in addr_local;
struct sockaddr_in addr_remote;
/* Get the Socket file descriptor */
if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
printf ("ERROR: Failed to obtain Socket Descriptor.\n");
return (0);
}
else printf ("[server] obtain socket descriptor successfully.\n");
/* Fill the local socket address struct */
addr_local.sin_family = AF_INET; // Protocol Family
addr_local.sin_port = htons(PORT); // Port number
addr_local.sin_addr.s_addr = INADDR_ANY; // AutoFill local address
bzero(&(addr_local.sin_zero), 8); // Flush the rest of struct
/* Bind a special Port */
if(bind(sockfd, (struct sockaddr*)&addr_local, sizeof(struct sockaddr)) == -1)
{
printf ("ERROR: Failed to bind Port %d.\n",PORT);
return (0);
}
else printf("[server] bind tcp port %d in addr 0.0.0.0 sucessfully.\n",PORT);
/* Listen remote connect/calling */
if(listen(sockfd,BACKLOG) == -1)
{
printf ("ERROR: Failed to listen Port %d.\n", PORT);
return (0);
}
else printf ("[server] listening the port %d sucessfully.\n", PORT);
int success = 0;
while(success == 0)
{
sin_size = sizeof(struct sockaddr_in);
/* Wait a connection, and obtain a new socket file despriptor for single connection */
if ((nsockfd = accept(sockfd, (struct sockaddr *)&addr_remote, &sin_size)) == -1)
printf ("ERROR: Obtain new Socket Despcritor error.\n");
else printf ("[server] server has got connect from %s.\n", inet_ntoa(addr_remote.sin_addr));
/* Child process */
if(!fork())
{
char* f_name = "send.txt";
char sdbuf[LENGTH]; // Send buffer
printf("[server] send %s to the client...", f_name);
FILE *fp = fopen(f_name, "r");
if(fp == NULL)
{
printf("ERROR: File %s not found.\n", f_name);
exit(1);
}
bzero(sdbuf, LENGTH);
int f_block_sz;
while((f_block_sz = fread(sdbuf, sizeof(char), LENGTH, fp))>0)
{
if(send(nsockfd, sdbuf, f_block_sz, 0) < 0)
{
printf("ERROR: Failed to send file %s.\n", f_name);
break;
}
bzero(sdbuf, LENGTH);
}
printf("ok!\n");
success = 1;
close(nsockfd);
printf("[server] connection closed.\n");
while(waitpid(-1, NULL, WNOHANG) > 0);
}
}
}
client.c
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define PORT 5000
#define LENGTH 512 // Buffer length
int main(int argc, char *argv[])
{
int sockfd; // Socket file descriptor
char revbuf[LENGTH]; // Receiver buffer
struct sockaddr_in remote_addr;
/* Get the Socket file descriptor */
if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
printf("ERROR: Failed to obtain Socket Descriptor!\n");
return (0);
}
/* Fill the socket address struct */
remote_addr.sin_family = AF_INET;
remote_addr.sin_port = htons(PORT);
inet_pton(AF_INET, "127.0.0.1", &remote_addr.sin_addr);
bzero(&(remote_addr.sin_zero), 8);
/* Try to connect the remote */
if (connect(sockfd, (struct sockaddr *)&remote_addr, sizeof(struct sockaddr)) == -1)
{
printf ("ERROR: Failed to connect to the host!\n");
return (0);
}
else printf("[client] connected to server at port %d...ok!\n", PORT);
//printf ("OK: Have connected to %s\n",argv[1]);
printf("[client] receive file sent by server to receive.txt...");
char* f_name = "receive.txt";
FILE *fp = fopen(f_name, "a");
if(fp == NULL) printf("File %s cannot be opened.\n", f_name);
else
{
bzero(revbuf, LENGTH);
int f_block_sz = 0;
int success = 0;
while(success == 0)
{
while(f_block_sz = recv(sockfd, revbuf, LENGTH, 0))
{
if(f_block_sz < 0)
{
printf("Receive file error.\n");
break;
}
int write_sz = fwrite(revbuf, sizeof(char), f_block_sz, fp);
if(write_sz < f_block_sz)
{
printf("File write failed.\n");
break;
}
bzero(revbuf, LENGTH);
}
printf("ok!\n");
success = 1;
fclose(fp);
}
}
close (sockfd);
printf("[client] connection lost.\n");
return (0);
}
Vielen Dank!
Mögliches Duplikat [Senden und dann eine Datei in der Socket-Programmierung in Linux Receive mit C/C++ (GCC/G ++)] (http://stackoverflow.com/questions/2014033/send-and-receive-a -file-in-socket-programmierung-in-linux-mit-cc-gcc-g) –