listen.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <unistd.h>
   4 #include <errno.h>
   5 #include <string.h>
   6 #include <sys/types.h>
   7 #include <sys/socket.h>
   8 #include <netinet/in.h>
   9 #include <netdb.h>
  10 #include <arpa/inet.h>
  11 #include <sys/wait.h>
  12 #include <signal.h>
  13 #include <libnotify/notify.h>
  14
  15 #define PORT "3490"
  16 #define QUEUE_LENGTH 10
  17
  18 // a function to reap future child processes
  19 void sigchld_handler(int s)
  20 {
  21         while(waitpid(-1, NULL, WNOHANG) > 0);
  22 }
  23
  24 // look for an IPv4 host:port in an address structure
  25 void *get_in_addr(struct sockaddr *sa)
  26 {
  27         if (sa->sa_family == AF_INET) {
  28                 return &(((struct sockaddr_in*)sa)->sin_addr);
  29         }
  30 }
  31
  32 int main(void)
  33 {
  34     // new connections on activefd, always listening on sockfd
  35         int sockfd, activefd;
  36         struct addrinfo hints, *servinfo, *port;
  37         struct sockaddr_storage their_addr;
  38         socklen_t sin_size;
  39         struct sigaction sa;
  40         char source[INET6_ADDRSTRLEN];
  41         int yes=1;
  42         int rv;
  43
  44         memset(&hints, 0, sizeof hints);
  45         hints.ai_family = AF_INET;
  46         hints.ai_socktype = SOCK_STREAM;
  47         hints.ai_flags = AI_PASSIVE;
  48
  49     // look up local address information
  50         if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
  51                 fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
  52                 return 1;
  53         }
  54
  55         // loop over available interfaces and try to bind to port
  56         for (port = servinfo; port != NULL; port = port->ai_next) {
  57                 if ((sockfd = socket(port->ai_family, port->ai_socktype,
  58                                 port->ai_protocol)) == -1) {
  59                         perror("irssi-notify: socket");
  60                         continue;
  61                 }
  62                 if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
  63                                 sizeof(int)) == -1) {
  64                         perror("setsockopt");
  65                         exit(1);
  66                 }
  67                 if (bind(sockfd, port->ai_addr, port->ai_addrlen) == -1) {
  68                         close(sockfd);
  69                         perror("irssi-notify: bind");
  70                         continue;
  71                 }
  72                 break;
  73         }
  74
  75         if (port == NULL)  {
  76                 fprintf(stderr, "irssi-notify: failed to bind\n");
  77                 return 2;
  78         }
  79
  80         freeaddrinfo(servinfo);
  81
  82         if (listen(sockfd, QUEUE_LENGTH) == -1) {
  83                 perror("listen");
  84                 exit(1);
  85         }
  86
  87     // bind sigchld_handler to reap future child processes
  88         sa.sa_handler = sigchld_handler;
  89         sigemptyset(&sa.sa_mask);
  90         sa.sa_flags = SA_RESTART;
  91         if (sigaction(SIGCHLD, &sa, NULL) == -1) {
  92                 perror("sigaction");
  93                 exit(1);
  94         }
  95
  96         printf("irssi-notify: waiting for connections...\n");
  97
  98         while (1) {
  99                 sin_size = sizeof their_addr;
 100                 activefd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
 101                 if (activefd == -1) {
 102                         perror("accept");
 103                         continue;
 104                 }
 105
 106                 inet_ntop(their_addr.ss_family,
 107                         get_in_addr((struct sockaddr *)&their_addr),
 108                         source, sizeof source);
 109
 110         // whitelist allowed
 111         if (strcmp(source, "50.16.219.8") != 0 &&
 112                 strcmp(source, "127.0.0.1") != 0){
 113             close(activefd);
 114             continue;
 115         }
 116
 117         // start a child process to handle notifications
 118                 if (!fork()) {
 119             // the child process doesn't need the listener
 120                         close(sockfd);
 121             char buf[4096];
 122             if (recv(activefd, buf, 99, 0) == -1) {
 123                 perror("recv");
 124                 exit(1);
 125             }
 126             buf[4096] = '\0';
 127             printf("irssi-notify: recieved '%s'\n", buf);
 128             notify_init("irssi-notify");
 129             NotifyNotification * notification =
 130                 notify_notification_new("", buf, "irssi-notify");
 131             notify_notification_show(notification, NULL);
 132                         close(activefd);
 133                         exit(0);
 134                 }
 135                 close(activefd);
 136         }
 137
 138         return 0;
 139 }