src/tests/kits/net/tcp_client.c

   1 /*
   2  * a stream socket client demo
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <unistd.h>
   8 #include <errno.h>
   9 #include <string.h>
  10 #include <netdb.h>
  11 #include <sys/types.h>
  12 #include <netinet/in.h>
  13 #include <sys/socket.h>
  14
  15
  16 #define PORT 1234               // the port client will be connecting to
  17 #define MAXDATASIZE 100 // max number of bytes we can get at once
  18
  19
  20 int
  21 main(int argc, char **argv)
  22 {
  23         int sockfd;
  24         char buffer[MAXDATASIZE];
  25         short int port = PORT;
  26         struct hostent *he;
  27         struct sockaddr_in their_addr;
  28                 // connector's address information
  29
  30         if (argc < 2) {
  31                 fprintf(stderr,"usage: tcp_client <hostname> [port]\n");
  32                 exit(1);
  33         }
  34
  35         if (argc == 3)
  36                 port = atoi(argv[2]);
  37
  38         if ((he = gethostbyname(argv[1])) == NULL) {
  39                 // get the host info
  40                 perror("gethostbyname");
  41                 exit(1);
  42         }
  43
  44         if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
  45                 perror("socket");
  46                 exit(1);
  47         }
  48
  49         memset(&their_addr, 0, sizeof(their_addr));
  50         their_addr.sin_family = AF_INET;
  51         their_addr.sin_port = htons(port);
  52         their_addr.sin_addr = *((struct in_addr *)he->h_addr);
  53
  54         if (connect(sockfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1) {
  55                 perror("connect");
  56                 exit(1);
  57         }
  58
  59         if (!fork()) {
  60                 int numBytes;
  61
  62                 while (1) {
  63                         // child process
  64                         if ((numBytes = recv(sockfd, buffer, sizeof(buffer) - 1, 0)) == -1) {
  65                                 perror("recv");
  66                                 sleep(1);
  67                                 // want the read thread to stay alive
  68                                 continue;
  69                         }
  70
  71                         buffer[numBytes] = '\0';
  72                         printf("%s", buffer);
  73                 }
  74         } else {
  75                 while (1) {
  76                         // parent process
  77                         if (fgets(buffer, sizeof(buffer) - 1, stdin) == NULL) {
  78                                 perror("fgets");
  79                                 exit(1);
  80                         }
  81
  82                         if ((send(sockfd, buffer, strlen(buffer), 0)) == -1) {
  83                                 perror("send");
  84                                 exit(1);
  85                         }
  86                 }
  87         }
  88
  89         close(sockfd);
  90
  91         return 0;
  92 }
  93