src/update_check.h

#include <signal.h>
#include <strings.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

int NUM_SEPS = 3;
int CONNECT_TIMEOUT = 5;

static int sTimeout = 0;

static void AlarmHandler(int sig)

{

   sTimeout = 1;

}

bool error(const char *msg)
{
   return false;
}

int parse_version_str(char* version_str)
{
   int version_int = 0;
   char* token = strtok(version_str,".");
    for(int i = 0; i < NUM_SEPS; ++i)
    {
      version_int += atoi(token)*(int)pow(100.,NUM_SEPS-i);
   }
   return version_int;
}

bool get_current_version(char* curr_version)
{
    int sockfd, portno, n;
    struct sockaddr_in serv_addr;
    struct hostent *server;
   
    portno = 80;
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0)

        return error("ERROR opening socket");
   
    server = gethostbyname("bio.math.berkeley.edu");
    if (server == NULL)

        return error("ERROR, no such host");

    bzero((char *) &serv_addr, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    bcopy((char *)server->h_addr,

        (char *)&serv_addr.sin_addr.s_addr,
        server->h_length);
    serv_addr.sin_port = htons(portno);

   signal(SIGALRM, AlarmHandler);

   sTimeout = 0;

   alarm(CONNECT_TIMEOUT);

   
   int ret;
   ret = connect(sockfd, (struct sockaddr*)&serv_addr, sizeof(serv_addr));
   if (ret < 0 || sTimeout)
   {
      return error("ERROR connecting");
   }
   
   char buffer[1024];
   strcpy(buffer, "GET /eXpress/curr_xprs_version HTTP/1.1\nHost: bio.math.berkeley.edu\n\n");
   n = (int)write(sockfd,buffer,1024);
   
    if (n < 0)

      return error("ERROR writing to socket");
   bzero(curr_version, sizeof(curr_version));
    n = (int)read(sockfd,buffer,1024);
    if (n < 0)

      return error("ERROR reading from socket");

   char* token;
   token = strtok(buffer, "$");
   token = strtok(NULL, "$");
   if (token==NULL)
      return error("ERROR parsing response");
   
   strcpy(curr_version, token);
      
   return true;
}

void check_version(const char* this_version)
{
   char curr_version[256];
    memset(curr_version, 0, sizeof(curr_version));
   if (get_current_version(curr_version))
   {
      if (strcmp(curr_version, this_version)==0) {
         fprintf(stderr, "You are using eXpress v%s, which is the most recent release.\n\n", PACKAGE_VERSION);
      } else {
         fprintf(stderr, "WARNING: Your version of eXpress is not up-to-date. It is recommended that you upgrade to v%s to benefit from the most recent features and bug fixes (http://bio.math.berkeley.edu/eXpress).\n\n", curr_version);
    }
   } else {
      fprintf(stderr, "WARNING: Could not connect to update server to verify current version. Please check at the eXpress website (http://bio.math.berkeley.edu/eXpress).\n\n");
   }
}