Reputation: 41

/bin/sleep: invalid time interval ‘’

I'm writing a client-server program where the server is a simple shell

all commands are working, except for /bin/sleep -- that is, rrsh> /bin/sleep 1&

I've included my entire shell code -- which includes:

checking to see if the command is valid from list of valid commands
then executes it if it is

my shell code looks like this:

      while((n = Rio_readlineb(&rio, buf, MAXLINE)) != 0){ //loop until connection has been terminated
  if (!strcmp(buf, "quit\n")){
    printf("User %s disconnected.\n", username);
    flag1 = 0; //the user will need to login again
  }
  if (flag1 == 1){ //the user is loged in
    bg = p3parseline(buf, argv_for_shell);
    strtok(buf, "\n");
    printf("User %s sent the command '%s' to be executed.\n", username, buf);
    strcat(argv_for_shell[0], "\n");

    //check if the command is allowed
    flag2 = 0; //set command allowed? flag back to false
    file = Fopen("rrshcommands.txt", "r");
    while (Fgets(command, MAXLINE, file) != NULL){
      if (!strcmp(argv_for_shell[0], command)){
        flag2 = 1;
      }
    }
    Fclose(file);

    strtok(argv_for_shell[0], "\n");

    if (flag2 == 0){ //case where the command is not allowed
      printf("The command '%s' is not allowed.\n", buf);
      strcpy(buf, "Command not allowed\n");
      Rio_writen(connfd, buf, strlen(buf));
    }
    else{
      if ((pid = fork()) == 0) {   /* Child runs user job */
        printf("Fork/Execing the command %s on behalf of the user.\n", argv_for_shell[0]);
        Dup2(connfd, 1);

        if (execve(argv_for_shell[0], argv_for_shell, environ) < 0) {
          printf("%s: Command not found.\n", argv_for_shell[0]);
          exit(0);
        }
      }
      /* Parent waits for foreground job to terminate */
      if (!bg) {
        int status;
        if (waitpid(pid, &status, 0) < 0)
          unix_error("waitfg: waitpid error");
        memset(&buf[0], 0, sizeof(buf)); //flush the buffer
        Rio_writen(connfd, buf, strlen(buf));
      }
      else{
        memset(&buf[0], 0, sizeof(buf)); //flush the buffer
        Rio_writen(connfd, buf, strlen(buf));
      }
      signal(SIGCHLD, reap_background);
    }
  }
  Close(connfd);
}

when I execute /bin/sleep 1& it should move onto the last else block and write back an empty string to the client

from debugging it's getting stuck in a weird place

93            if ((pid = fork()) == 0) {   /* Child runs user job */
(gdb) p bg
$1 = 1
(gdb) n
104           if (!bg) {
(gdb) Fork/Execing the command /bin/sleep on behalf of the user.
/bin/sleep: invalid time interval ‘’
Try '/bin/sleep --help' for more information.

you can see that bg == 1, so I would guess it's hung up in the execve code -- which is why I'm getting that error. But why would gdb move onto the next line?

Upvotes: 0