webserver2.c

#include <stdio.h>
#include <sys/stat.h>  /* for mkfifo */
#include <sys/types.h>  /* for open */
#include <sys/stat.h>  /* for open */
#include <fcntl.h>    /* for open */
#include <unistd.h>   /* for write */
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <signal.h>
#define BUFFSIZE 8192
#define MaxPipeName 100
#define logdir "/home/ruttan/classes/capstone/debugger/"
#define interface "interface"
#define numDbgArgs 5

pid_t child_pid;
void catch_sigint(int sig_num)
{
    /* re-set the signal handler again to catch_int, for next time */
    printf("got signal sigint\n");
    fflush(stdout);
    signal(SIGINT, catch_sigint);
    kill(child_pid,SIGINT); 
    exit(1);
}

void make_args(char * id,char * argv[]){
  char *prog;
  prog=(char *)malloc(MaxPipeName);
  sprintf(prog,"%s%s",logdir,interface);
  argv[0]=prog;
  argv[1]=id;
  argv[2]=0;  
}

pid_t launch_interface(char * argv[]){
  int stdio[3];
  pid_t child_pidt;
  usleep(10000);
  switch (child_pidt=fork()){
  case -1:
     perror("Could not fork debugger");
     exit(1);
     break;
  case 0:
    if (execvp(argv[0],argv)==-1){
      perror("exec failed");
      printf("exec =%s",argv[0]);
      fflush(stdout);
      exit(1);
    }
    //after fork in parent
  }
  free(argv[0]);
  return(child_pidt);   
}

main (int argc,char** argv ) {
    int fd,i;    
    int len,n;
    char line[BUFFSIZE];
    char c;
    char * nargv[numDbgArgs];
    int fdtoDbg,fdfrmDbg,fileCheckO,fileCheckI,errnoO,errnoI;
    struct stat stat_bufO, stat_bufI;
    char buf[BUFFSIZE],toDebugger[MaxPipeName],fromDebugger[MaxPipeName];
    if ((argc < 2 )|| (argc >=3)){
      perror("usage: webserver idcode");
      exit(1);
    }
    signal(SIGINT, catch_sigint);   
    sprintf(toDebugger,"%s%s%s",logdir,"OUT",argv[1]);
    sprintf(fromDebugger,"%s%s%s",logdir,"IN",argv[1]);
    fileCheckO=stat(toDebugger,&stat_bufO);
    errnoO=errno;
    fileCheckI=stat(fromDebugger,&stat_bufI); 
    errnoI=errno;

    if ((fileCheckO == -1) && (fileCheckI == -1)) {
      if ((errnoO==2) && (errnoI==2)){
	printf("NEITHER files exists\n");
        fflush(stdout);
	make_args(argv[1],nargv);
	child_pid=launch_interface(nargv);
	usleep(10000);
      }
      else{
         printf("errnoI=%s\n",strerror(errnoI));
         printf("errnoO=%s\n",strerror(errnoO));
        fflush(stdout);
        exit(0);
      }

    } else {
      if ((errnoO == 0) && (errnoI == 0) &&
	  S_ISFIFO(stat_bufO.st_mode) && S_ISFIFO(stat_bufI.st_mode)){
	printf("both files are FIFOs\n");
        fflush(stdout);
	}
      else{
        printf("files exist in impossible state--correcting\n");
        if (!fileCheckO) unlink(toDebugger);
        if (!fileCheckI) unlink(fromDebugger);
        fflush(stdout);
 	make_args(argv[1],nargv);
	child_pid=launch_interface(nargv);
	usleep(10000);
      }
    }
   
    
  //create output pipe to webserver


    if ((fdtoDbg = open(toDebugger,O_WRONLY)) == -1) {
      perror("cannot open fifo to debugger");
      exit(1);
    }
   //create input pipe from webserver
      if ((fdfrmDbg = open(fromDebugger,O_RDONLY)) == -1) {
      perror("cannot open fifo from debugger");
      exit(1);
    }
	
    while(1) {
      line[0]=0;
      while (!strstr(line,">>>")&& !strstr(line,"...")  ){
        if ((n=read(fdfrmDbg,line,BUFFSIZE))){
           line[n]=0;
           printf("%d-web:%s",n,line);
           fflush(stdout);
        }
        else{
          printf("null read on fdfrmDbg\n");
          fflush(stdout);
	  exit(1);
        }
      } 
      i=0;
      while ((c=getchar())!='\n'){
	line[i++]=c;
      }
      line[i]=c;
      if  (strstr(line,"#123")){
        printf("webserver2 exiting\n");
        fflush(stdout);
        break;    
      } 
      write(fdtoDbg,line,i+1);
    }  
    exit(0);
}