我正在编写一个C程序，以便能够使用TCP / IP套接字在raspberry pi和windows pc计算机之间（从服务器raspberry pi到客户端PC）连续传输图像文件，但似乎有一个发送第1017次后发生错误，服务器通过声明分段故障退出，我的意思是在我打算将图像文件发送到我的客户端2000次时，服务器退出第1017个图像。
服务器端
#include<stdio.h>
#include<string.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<unistd.h>
#include<iostream>
#include<fstream>
#include<errno.h>
using namespace std;
int send_image(int socket){
FILE *picture;
int size, read_size, stat, packet_index;
char send_buffer[10240], read_buffer[256];
packet_index = 1;
picture = fopen("a.jpg", "r");
printf("Getting Picture Size\n");
if(picture == NULL) {
printf("Error Opening Image File");
}
fseek(picture, 0, SEEK_END);
size = ftell(picture);
fseek(picture, 0, SEEK_SET);
printf("Total Picture size: %i\n",size);
//Send Picture Size
printf("Sending Picture Size\n");
write(socket, (void *)&size, sizeof(int));
//Send Picture as Byte Array
printf("Sending Picture as Byte Array\n");
do { //Read while we get errors that are due to signals.
stat=read(socket, &read_buffer , 255);
printf("Bytes read: %i\n",stat);
} while (stat < 0);
printf("Received data in socket\n");
printf("Socket data: %c\n", read_buffer);
while(!feof(picture)) {
//while(packet_index = 1){
//Read from the file into our send buffer
read_size = fread(send_buffer, 1, sizeof(send_buffer)-1, picture);
//Send data through our socket
do{
stat = write(socket, send_buffer, read_size);
}while (stat < 0);
printf("Packet Number: %i\n",packet_index);
printf("Packet Size Sent: %i\n",read_size);
printf(" \n");
printf(" \n");
packet_index++;
//Zero out our send buffer
bzero(send_buffer, sizeof(send_buffer));
}
}
int main(int argc , char *argv[])
{
int socket_desc , new_socket , c, read_size,buffer = 0;
struct sockaddr_in server , client;
char *readin;
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1)
{
printf("Could not create socket");
}
//Prepare the sockaddr_in structure
server.sin_family = AF_INET;
server.sin_addr.s_addr = INADDR_ANY;
server.sin_port = htons( 8000 );
//Bind
if( bind(socket_desc,(struct sockaddr *)&server , sizeof(server)) < 0)
{
puts("bind failed");
return 1;
}
puts("bind done");
//Listen
listen(socket_desc , 3);
//Accept and incoming connection
puts("Waiting for incoming connections...");
c = sizeof(struct sockaddr_in);
if((new_socket = accept(socket_desc, (struct sockaddr *)&client, (socklen_t*)&c))){
puts("Connection accepted");
}
fflush(stdout);
if (new_socket<0)
{
perror("Accept Failed");
return 1;
}
while(value<2000)
{
value =value+1;
send_image(new_socket);
}
close(socket_desc);
fflush(stdout);
return 0;
}
客户端。
#include<stdio.h>
#include<string.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<sys/ioctl.h>
#include<unistd.h>
#include<iostream>
#include<fstream>
#include<errno.h>
using namespace std;
//This function is to be used once we have confirmed that an image is to be sent
//It should read and output an image file
int receive_image(int socket)
{ // Start function
int imgc = 0 ;
while(imgc < 2000)
{
int buffersize = 0, recv_size = 0,size = 0, read_size, write_size, packet_index =1,stat;
char imagearray[10240],verify = '1';
FILE *image;
int value = 0 ;
//Find the size of the image
value = value + 1;
do{
stat = read(socket, &size, sizeof(int));
}while(stat<0);
printf("size = %d" , size) ;
if(size>1000)
{
imgc = imgc + 1 ;
char buffer[] = "Got it";
//Send our verification signal
do{
stat = write(socket, &buffer, sizeof(int));
}while(stat<0);
printf("Reply sent\n");
printf(" \n");
char fn[100] ;
sprintf(fn,"a%d.jpg",imgc);
image = fopen(fn, "wb");
if( image == NULL) {
printf("Error has occurred. Image file could not be opened\n");
return -1;
}
//Loop while we have not received the entire file yet
int need_exit = 0;
struct timeval timeout = {10,0};
fd_set fds;
int buffer_fd, buffer_out;
while(recv_size < size) {
//while(packet_index < 2){
FD_ZERO(&fds);
FD_SET(socket,&fds);
buffer_fd = select(FD_SETSIZE,&fds,NULL,NULL,&timeout);
if (buffer_fd < 0)
printf("error: bad file descriptor set.\n");
if (buffer_fd == 0)
printf("error: buffer read timeout expired.\n");
if (buffer_fd > 0)
{
do{
read_size = read(socket,imagearray, 10240);
}while(read_size <0);
printf("Packet number received: %i\n",packet_index);
printf("Packet size: %i\n",read_size);
//Write the currently read data into our image file
write_size = fwrite(imagearray,1,read_size, image);
printf("Written image size: %i\n",write_size);
if(read_size !=write_size) {
printf("error in read write\n");
}
//Increment the total number of bytes read
recv_size += read_size;
packet_index++;
printf("Total received image size: %i\n",recv_size);
printf(" \n");
printf(" \n");
}
}
fclose(image);
printf("Image successfully Received!\n");
}
}
return 1;
}
int main(int argc , char *argv[])
{
int socket_desc;
struct sockaddr_in server;
char *parray;
//Create socket
socket_desc = socket(AF_INET , SOCK_STREAM , 0);
if (socket_desc == -1) {
printf("Could not create socket");
}
memset(&server,0,sizeof(server));
server.sin_addr.s_addr = inet_addr("192.168.137.137");
server.sin_family = AF_INET;
server.sin_port = htons( 8000 );
//Connect to remote server
if (connect(socket_desc , (struct sockaddr *)&server , sizeof(server)) < 0) {
cout<<strerror(errno);
close(socket_desc);
puts("Connect Error");
return 1;
}
puts("Connected\n");
receive_image(socket_desc);
close(socket_desc);
return 0;
}
答案 0 :(得分：2)
这可能来自于您使用每个可用的fd这一事实，因为您从不关闭任何文件描述符并继续打开它们。您确定永远不会将"Error Opening Image File"行视为输出吗？如果您这样做，那么您只需尝试fseek(NULL)，但这样做效果不佳。
无论如何，你的代码中还有很多奇怪的东西。
为什么使用bzero()而不是memset()？
为什么使用printf(%c)来显示字符串而不是printf(%s)
编辑：using namespace std;我觉得在c中没有多大意义。
为什么使用
do{
stat = write(socket, send_buffer, read_size);
}while (stat < 0);
只要你有错误，你就会写。同样适合阅读。此外，写入可能并不总是一次写入整个数据。这意味着你需要检查它是否确实。
为什么要保留未使用的变量，例如verify。
您应该使用编译标志来防止这些。如果您正在使用clang或gcc，则可以将-Wall -Wextra添加到编译行。
您可以尝试使用valgrind找到错误：valgrind ./your_program your arguments它会为您提供有关程序失败位置的信息。如果您使用它，请务必在编译行中添加-g以添加调试符号