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 IPv4/6 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         return &(((struct sockaddr_in6*)sa)->sin6_addr);
  31 }
  32
  33 int main(void)
  34 {
  35     // new connections on activefd, always listening on sockfd
  36         int sockfd, activefd;
  37         struct addrinfo hints, *servinfo, *port;
  38         struct sockaddr_storage their_addr;
  39         socklen_t sin_size;
  40         struct sigaction sa;
  41         char source[INET6_ADDRSTRLEN];
  42         int yes=1;
  43         int rv;
  44
  45         memset(&hints, 0, sizeof hints);
  46         hints.ai_family = AF_INET;
  47         hints.ai_socktype = SOCK_STREAM;
  48         hints.ai_flags = AI_PASSIVE;
  49
  50     // look up local address information
  51         if ((rv = getaddrinfo(NULL, PORT, &hints, &servinfo)) != 0) {
  52                 fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
  53                 return 1;
  54         }
  55
  56         // loop over available interfaces and try to bind to port
  57         for (port = servinfo; port != NULL; port = port->ai_next) {
  58                 if ((sockfd = socket(port->ai_family, port->ai_socktype,
  59                                 port->ai_protocol)) == -1) {
  60                         perror("irssi-notify: socket");
  61                         continue;
  62                 }
  63                 if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes,
  64                                 sizeof(int)) == -1) {
  65                         perror("setsockopt");
  66                         exit(1);
  67                 }
  68                 if (bind(sockfd, port->ai_addr, port->ai_addrlen) == -1) {
  69                         close(sockfd);
  70                         perror("irssi-notify: bind");
  71                         continue;
  72                 }
  73                 break;
  74         }
  75
  76         if (port == NULL)  {
  77                 fprintf(stderr, "irssi-notify: failed to bind\n");
  78                 return 2;
  79         }
  80
  81         freeaddrinfo(servinfo);
  82
  83         if (listen(sockfd, QUEUE_LENGTH) == -1) {
  84                 perror("listen");
  85                 exit(1);
  86         }
  87
  88     // bind sigchld_handler to reap future child processes
  89         sa.sa_handler = sigchld_handler;
  90         sigemptyset(&sa.sa_mask);
  91         sa.sa_flags = SA_RESTART;
  92         if (sigaction(SIGCHLD, &sa, NULL) == -1) {
  93                 perror("sigaction");
  94                 exit(1);
  95         }
  96
  97         printf("irssi-notify: waiting for connections...\n");
  98
  99         while (1) {
 100                 sin_size = sizeof their_addr;
 101                 activefd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size);
 102                 if (activefd == -1) {
 103                         perror("accept");
 104                         continue;
 105                 }
 106
 107                 inet_ntop(their_addr.ss_family,
 108                         get_in_addr((struct sockaddr *)&their_addr),
 109                         source, sizeof source);
 110
 111         // whitelist allowed
 112         if (strcmp(source, "50.16.219.8") != 0 &&
 113                 strcmp(source, "127.0.0.1") != 0){
 114             close(activefd);
 115             continue;
 116         }
 117
 118         // start a child process to handle notifications
 119                 if (!fork()) {
 120             // the child process doesn't need the listener
 121                         close(sockfd);
 122             char buf[4096];
 123             if (recv(activefd, buf, 99, 0) == -1) {
 124                 perror("recv");
 125                 exit(1);
 126             }
 127             buf[4096] = '\0';
 128             printf("irssi-notify: recieved '%s'\n", buf);
 129             notify_init("irssi-notify");
 130             NotifyNotification * notification =
 131                 notify_notification_new("", buf, "irssi-notify");
 132             notify_notification_show(notification, NULL);
 133                         close(activefd);
 134                         exit(0);
 135                 }
 136                 close(activefd);
 137         }
 138
 139         return 0;
 140 }