#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <errno.h>
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#include <ctype.h>
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#include <time.h>
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#include <pthread.h>
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#include <getopt.h>
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#include <libgen.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 <netinet/in.h>
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typedef struct link_node_s
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{
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int fd;
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struct link_node_s *next;
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} link_node_t;
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static inline void msleep(unsigned long ms);
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static inline void print_usage(char *progname);
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int socket_server_init(char *listen_ip, int listen_port);
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int add_fd_list(link_node_t **head, int fd);
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link_node_t *list_remove_node(link_node_t **head, link_node_t *node);
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int main(int argc, char **argv)
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{
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int listenfd, connfd;
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int serv_port = 0;
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int daemon_run = 0;
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char *progname = NULL;
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int opt;
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fd_set rdset;
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link_node_t *client_list = NULL; /* client fd link list, we will not use arrary for it get max client limite */
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link_node_t *node;
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int rv;
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int i;
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int maxfd=0;
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char buf[1024];
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struct option long_options[] =
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{
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{"daemon", no_argument, NULL, 'b'},
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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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progname = basename(argv[0]);
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/* Parser the command line parameters */
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while ((opt = getopt_long(argc, argv, "bp:h", long_options, NULL)) != -1)
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{
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switch (opt)
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{
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case 'b':
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daemon_run=1;
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break;
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case 'p':
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serv_port = atoi(optarg);
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break;
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case 'h': /* Get help information */
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print_usage(progname);
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return EXIT_SUCCESS;
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default:
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break;
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}
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}
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if( !serv_port )
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{
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print_usage(progname);
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return -1;
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}
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if( (listenfd=socket_server_init(NULL, serv_port)) < 0 )
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{
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printf("ERROR: %s server listen on port %d failure\n", argv[0],serv_port);
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return -2;
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}
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printf("%s server start to listen on port %d\n", argv[0],serv_port);
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/* set program running on background */
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if( daemon_run )
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{
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daemon(0, 0);
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}
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printf("add listen socket[%d] into client list\n", listenfd );
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add_fd_list(&client_list, listenfd);
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for ( ; ; )
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{
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FD_ZERO(&rdset);
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for( node=client_list; node!=NULL; node=node->next )
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{
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//printf("Add socket[%d] in select readset\n", node->fd);
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maxfd = node->fd>maxfd ? node->fd : maxfd;
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FD_SET(node->fd, &rdset);
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}
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/* program will blocked here */
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rv = select(maxfd+1, &rdset, NULL, NULL, NULL);
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if(rv < 0)
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{
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printf("select failure: %s\n", strerror(errno));
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break;
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}
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else if(rv == 0)
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{
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printf("select get timeout\n");
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continue;
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}
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/* listen socket get event means new client start connect now */
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if ( FD_ISSET(listenfd, &rdset) )
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{
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if( (connfd=accept(listenfd, (struct sockaddr *)NULL, NULL)) < 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[%d] and add it into client list\n", connfd );
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add_fd_list(&client_list, connfd);
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}
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else /* data arrive from already connected client */
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{
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node = client_list;
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while( node != NULL )
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{
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if( !FD_ISSET(node->fd, &rdset) )
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{
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node = node->next;
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continue;
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}
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if( (rv=read(node->fd, buf, sizeof(buf))) <= 0)
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{
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printf("socket[%d] read failure or get disconncet.\n", node->fd);
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/* list_remove_node will return the previous node */
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node = list_remove_node(&client_list, node);
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}
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else
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{
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printf("socket[%d] read get %d bytes data\n", node->fd, rv);
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/* convert letter from lowercase to uppercase */
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for(i=0; i<rv; i++)
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buf[i]=toupper(buf[i]);
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if( write(node->fd, buf, rv) < 0 )
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{
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printf("socket[%d] write failure: %s\n", node->fd, strerror(errno));
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/* list_remove_node will return the previous node */
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node = list_remove_node(&client_list, node);
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}
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}
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if( node != NULL )
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{
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node = node->next;
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}
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} /* while( node != NULL ) */
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}
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}
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CleanUp:
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close(listenfd);
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return 0;
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}
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static inline void msleep(unsigned long ms)
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{
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struct timeval tv;
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tv.tv_sec = ms/1000;
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tv.tv_usec = (ms%1000)*1000;
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select(0, NULL, NULL, NULL, &tv);
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}
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static inline void print_usage(char *progname)
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{
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printf("Usage: %s [OPTION]...\n", progname);
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printf(" %s is a socket server program, which used to verify client and echo back string from it\n", progname);
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printf("\nMandatory arguments to long options are mandatory for short options too:\n");
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printf(" -b[daemon ] set program running on background\n");
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printf(" -p[port ] Socket server port address\n");
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printf(" -h[help ] Display this help information\n");
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printf("\nExample: %s -b -p 8900\n", progname);
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return ;
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}
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int socket_server_init(char *listen_ip, int listen_port)
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{
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struct sockaddr_in servaddr;
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int rv = 0;
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int on = 1;
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int listenfd;
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if ( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
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{
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printf("Use socket() to create a TCP socket failure: %s\n", strerror(errno));
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return -1;
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}
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/* Set socket port reuseable, fix 'Address already in use' bug when socket server restart */
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setsockopt(listenfd, 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(listen_port);
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if( !listen_ip ) /* Listen all the local IP address */
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{
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servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
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}
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else /* listen the specified IP address */
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{
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if (inet_pton(AF_INET, listen_ip, &servaddr.sin_addr) <= 0)
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{
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printf("inet_pton() set listen IP address failure.\n");
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rv = -2;
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goto CleanUp;
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}
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}
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if(bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0)
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{
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printf("Use bind() to bind the TCP socket failure: %s\n", strerror(errno));
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rv = -3;
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goto CleanUp;
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}
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if(listen(listenfd, 13) < 0)
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{
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printf("Use bind() to bind the TCP socket failure: %s\n", strerror(errno));
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rv = -4;
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goto CleanUp;
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}
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CleanUp:
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if(rv<0)
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close(listenfd);
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else
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rv = listenfd;
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return rv;
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}
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int add_fd_list(link_node_t **head, int fd)
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{
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link_node_t *node;
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link_node_t *tmp;
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if( NULL == (node=(link_node_t *)malloc(sizeof(*node))) )
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{
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printf("malloc for new node failure\n");
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return -1;
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}
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memset(node, 0, sizeof(*node));
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node->fd = fd;
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node->next = NULL;
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if( *head == NULL )
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{
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*head = node;
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return 0;
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}
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tmp = *head;
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while( tmp->next != NULL )
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{
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tmp=tmp->next;
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}
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tmp->next = node;
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}
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/* list_remove_node will return the previous node */
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link_node_t *list_remove_node(link_node_t **head, link_node_t *node)
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{
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link_node_t *prev;
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close(node->fd);
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if( node == *head )
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{
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*head = NULL;
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free(node);
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return NULL;
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}
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else
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{
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for(prev=*head; prev!=NULL; prev=prev->next)
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{
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if(prev->next == node)
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{
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prev->next = node->next;
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free(node);
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return prev;
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}
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}
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}
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}
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