#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <arpa/inet.h>
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#include <stdlib.h>
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#include <getopt.h>
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#include <ctype.h>
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void print_usage(char *progname)
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{
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printf("%s usage: \n", progname);
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printf("-p(--port): sepcify server listen port.\n");
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printf("-h(--Help): print this help information.\n");
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return ;
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}
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int main(int argc, char **argv)
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{
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int sockfd = -1;
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int rv = -1;
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struct sockaddr_in servaddr;
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struct sockaddr_in cliaddr;
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socklen_t len;
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int port = 0;
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int clifd;
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int ch;
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int on = 1;
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pid_t pid;
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struct option opts[] = {
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{"port", required_argument, NULL, 'p'},
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{"help", no_argument, NULL, 'h'},
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{NULL, 0, NULL, 0}
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};
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while( (ch=getopt_long(argc, argv, "p:h", opts, NULL)) != -1 )
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{
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switch(ch)
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{
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case 'p':
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port=atoi(optarg);
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break;
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case 'h':
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print_usage(argv[0]);
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return 0;
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}
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}
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if( !port )
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{
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print_usage(argv[0]);
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return 0;
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}
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sockfd=socket(AF_INET, SOCK_STREAM, 0);
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if(sockfd < 0)
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{
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printf("Create socket failure: %s\n", strerror(errno));
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return -1;
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}
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printf("Create socket[%d] successfully!\n", sockfd);
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setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
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memset(&servaddr, 0, sizeof(servaddr));
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servaddr.sin_family=AF_INET;
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servaddr.sin_port = htons(port);
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servaddr.sin_addr.s_addr = htonl(INADDR_ANY); /* listen all the IP address on this host */
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//inet_aton("192.168.0.16", &servaddr.sin_addr); /* Only listen specify IP address on this host */
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rv=bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
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if(rv < 0)
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{
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printf("Socket[%d] bind on port[%d] failure: %s\n", sockfd, port, strerror(errno));
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return -2;
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}
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listen(sockfd, 13);
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printf("Start to listen on port [%d]\n", port);
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while(1)
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{
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printf("Start accept new client incoming...\n");
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clifd=accept(sockfd, (struct sockaddr *)&cliaddr, &len);
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if(clifd < 0)
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{
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printf("Accept new client failure: %s\n", strerror(errno));
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continue;
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}
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printf("Accept new client[%s:%d] successfully\n", inet_ntoa(cliaddr.sin_addr), ntohs(cliaddr.sin_port));
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pid = fork();
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if( pid < 0 )
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{
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printf("fork() create child process failure: %s\n", strerror(errno));
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close(clifd);
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continue;
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}
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else if( pid > 0 )
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{
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/* Parent process close client fd and goes to accept new socket client again */
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close(clifd);
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continue;
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}
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else if ( 0 == pid )
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{
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char buf[1024];
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int i;
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printf("Child process start to commuicate with socket client...\n");
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close(sockfd); /* Child process close the listen socket fd */
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while(1)
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{
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memset(buf, 0, sizeof(buf));
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rv=read(clifd, buf, sizeof(buf));
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if( rv < 0 )
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{
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printf("Read data from client sockfd[%d] failure: %s\n", clifd, strerror(errno));
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close(clifd);
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exit(0);
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}
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else if( rv == 0)
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{
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printf("Socket[%d] get disconnected\n", clifd);
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close(clifd);
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exit(0);
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}
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else if( rv > 0 )
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{
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printf("Read %d bytes data from Server: %s\n", rv, buf);
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}
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/* convert letter from lowercase to uppercase */
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for(i=0; i<rv; i++)
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{
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buf[i]=toupper(buf[i]);
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}
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rv=write(clifd, buf, rv);
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if(rv < 0)
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{
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printf("Write to client by sockfd[%d] failure: %s\n", clifd, strerror(errno));
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close(clifd);
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exit(0);
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}
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} /* Child process loop */
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} /* Child process start*/
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}
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close(sockfd);
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return 0;
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}
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