server/src/xylsocket.c

   1 /* All rights reserved.
   2  *
   3  * 文件名称：xylsocket.c
   4  * 摘    要：对socket函数进行封装
   5  * 当前版本：1.0
   6  * 作    者：董溥
   7  * 完成日期：2007年5月13日
   8  *
   9  *修改人员：林峰
  10  *修改日期：2007年6月6日
  11  *修改：王聪
  12  *修改日期：2007.8.4
  13  */
  14
  15 #include "xylftp.h"
  16 #include "debug.h"
  17
  18 extern struct user_env user_env;
  19 extern struct run_env run_env;
  20
  21 extern void telnet(void);
  22
  23 int r_close(int fd)
  24 {
  25         int state;
  26         while ((state = close(fd)) == -1 && errno == EINTR) {
  27                 continue;
  28         }
  29         return state;
  30 }
  31 void listen_connect(void)
  32 {
  33         int socket_fd;
  34         int connect_fd;
  35         pid_t child_pid;
  36         #ifdef  DEBUG
  37         run_env.ftp_port = 1986;
  38         #endif
  39         if ((socket_fd = xyl_listen(run_env.ftp_port)) == -1) {
  40                 exit(1);
  41         }
  42         while (1) {
  43                 if ((connect_fd = xyl_accept(socket_fd)) == -1) {
  44                         if (r_close(socket_fd) == -1) {
  45                                 LOG_IT("close error.");
  46                         }
  47                         exit(1);
  48                 }
  49                 user_env.connect_fd = connect_fd;
  50
  51                 debug_printf("run to fork.\n");
  52
  53                 signal(SIGCLD,SIG_IGN);         /*to avoid zombie process*/
  54
  55                 if ((child_pid = fork()) == -1) {
  56                         LOG_IT("fork error.");
  57                 }
  58                 else if (child_pid) {                   /*parent*/
  59                         if (r_close(user_env.connect_fd) == -1) {
  60                                 LOG_IT("close error.");
  61                         }
  62                         continue;
  63                 }
  64                 else if (child_pid == 0) {
  65                         if (r_close(socket_fd) == -1) {
  66                                 LOG_IT("close error.");
  67                         }
  68
  69                         telnet();
  70
  71                         if (r_close(user_env.connect_fd) == -1) {
  72                                 LOG_IT("close connect_fd error.");
  73                         }
  74                         exit(0);
  75                 }
  76         }
  77 }
  78 int xyl_listen(short port)
  79 {
  80         int socket_fd;
  81         struct sockaddr_in server_addr;
  82         bzero(&server_addr, sizeof(server_addr));       /*initial socket address to zero*/
  83         server_addr.sin_family = AF_INET;                       /*use IPv4*/
  84         server_addr.sin_addr.s_addr = htonl(INADDR_ANY);        /*use localhost IP*/
  85         server_addr.sin_port = htons(port);                     /*convert from host byte order to network byte order*/
  86
  87         if ((socket_fd = socket(AF_INET,SOCK_STREAM,0)) == -1) {
  88                 LOG_IT("socket error.");
  89                 if (errno == ENFILE){
  90                         LOG_IT("The  system  limit  on  the  total number of open files has been reached.");
  91                 }
  92                 else if (errno == EPROTONOSUPPORT) {
  93                         LOG_IT("The  protocol  type  or  the specified protocol is not supported within this domain.");
  94                 }
  95                 else if (errno == EACCES) {
  96                         LOG_IT("Permission  to create a socket of the specified type and/or protocol is denied.");
  97                 return -1;
  98                 }
  99         }
 100
 101         if ((bind(socket_fd,(struct sockaddr *) &server_addr,sizeof(server_addr)) == -1)) {
 102                 LOG_IT("bind error.");
 103                 if (errno == EADDRINUSE) {
 104                         LOG_IT("The given address is already in use.");
 105                 }
 106                 else if (errno == EBADF) {
 107                         LOG_IT("sock_fd is not a valid descriptor.");
 108                 }
 109                 else if (errno == EACCES) {
 110                         LOG_IT("The address is protected.");
 111                 }
 112                 if (r_close(socket_fd) == -1) {
 113                         LOG_IT("close socket_fd error.");
 114                 }
 115                 return -1;
 116         }
 117
 118         if (listen(socket_fd,LISTENQ) == -1) {
 119                 LOG_IT("listen error.");
 120                 if (errno == EADDRINUSE) {
 121                         LOG_IT("Another socket is already listening on the same port.");
 122                         return -1;
 123                 }
 124         }
 125
 126         return socket_fd;
 127 }
 128
 129
 130 int xyl_accept(int socket_fd)
 131 {
 132         int connect_fd;
 133         socklen_t len;
 134         struct sockaddr_in client_addr;
 135         while (1) {
 136                 len = sizeof(client_addr);
 137                 if ((connect_fd = accept(socket_fd, (struct sockaddr *)&client_addr,&len)) == -1
 138                                 && errno == EINTR) {
 139                         continue;
 140                 }
 141                 if (connect_fd == -1) {
 142                         LOG_IT("accept error.");
 143                         if (errno == ECONNABORTED) {
 144                                 LOG_IT("A connection has been aborted.");
 145                         }
 146                         else if (errno == EPERM) {
 147                                 LOG_IT("Firewall rules forbid connection.");
 148                         }
 149                         else if (errno == ENFILE) {
 150                                 LOG_IT("The system limit on the total number of open files has been reached.");
 151                         }
 152                         else if (errno == EINTR) {
 153                                 LOG_IT("The system call was interrupted by a signal that was"
 154                                         "caught before a valid connection arrived.");
 155                         }
 156                 }
 157                 break;
 158         }
 159         strcpy(user_env.client_ip, inet_ntoa(client_addr.sin_addr));
 160         return connect_fd;
 161 }
 162
 163
 164 int xyl_connect(char *hostname,short port)
 165 {
 166         int socket_fd;
 167         int ret;
 168         struct sockaddr_in server_addr;
 169         socklen_t len;
 170
 171         server_addr.sin_port = htons(port);
 172         server_addr.sin_family = AF_INET;
 173         if ((inet_aton(hostname, &server_addr.sin_addr)) == 0) {
 174                 LOG_IT("invalid address.");
 175                 return -1;
 176         }
 177         /*bzero(&(server_addr.sin_zero),8);*/
 178
 179         if ((socket_fd = socket(AF_INET,SOCK_STREAM,0)) == -1) {
 180                 LOG_IT("socket error.");
 181                 if (errno == ENFILE){
 182                         LOG_IT("The  system  limit  on  the  total number of open files has been reached.");
 183                 }
 184                 else if (errno == EPROTONOSUPPORT) {
 185                         LOG_IT("The  protocol  type  or  the specified protocol is not supported within this domain.");
 186                 }
 187                 else if (errno == EACCES) {
 188                         LOG_IT("Permission  to create a socket of the specified type and/or protocol is denied.");
 189                 }
 190                 return -1;
 191
 192         }
 193
 194         while (1) {
 195                 len = sizeof(server_addr);
 196                 if (((ret = connect(socket_fd, (struct sockaddr *)&server_addr, len)) == -1
 197                                 && errno == EINTR) || errno == EALREADY) {
 198                         continue;
 199                 }
 200                 if (ret == -1) {
 201                         LOG_IT("connect error.");
 202                         if (errno == ENETUNREACH) {
 203                                 LOG_IT("Network is unreachable.");
 204                         }
 205                         else if (errno == ETIMEDOUT) {
 206                                 LOG_IT("Timeout while attempting connection.");
 207                         }
 208                         else if (errno == EISCONN) {
 209                                 LOG_IT("The socket is already connected.");
 210                         }
 211                         else if (errno == ECONNREFUSED) {
 212                                 LOG_IT("No one listening on the remote address.");
 213                         }
 214                         if (r_close(socket_fd) == -1) {
 215                                 LOG_IT("close socket_fd error.");
 216                         }
 217                         return -1;
 218                 }
 219                 break;
 220         }
 221         return socket_fd;
 222 }
 223
 224
 225