atm_svr_processes.c

linux 多线程例子

  open_account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(open_account_sem_id, &open_account_sem_buf, 1) < 0) {
    perror("SERVER: child process, open account p semop() failed %d\n");
    exit (1);
  }
#endif

  /* Get a new account */
  if ((rtn = new_account(&id, &accountp)) < 0) {
    DPRINTF(("SERVER: open new_account failed, %s\n", atm_err_tbl[-rtn]));
    sprintf(resp_buf, "%d %d %d %s", 
	    TRANS_FAILURE, 
	    -1, 
	    -1,
	    atm_err_tbl[-rtn]);
  } else {
    accountp->password = id;
    accountp->balance  = 0;
    
    /* Store it back to the database */
    if ((rtn = store_account(accountp)) < 0) {
      DPRINTF(("SERVER: open, store_account failed %s\n", atm_err_tbl[-rtn]));
      sprintf(resp_buf, "%d %d %d %s", 
	    TRANS_FAILURE, 
	    -1, 
	    -1,
	    atm_err_tbl[-rtn]);
    } else {
      sprintf(resp_buf, "%d %d %d", 
	    TRANS_SUCCESS,  
	    id, 
	    id);
    }
  }

#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "v()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = 1; /* "v()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER child process, single_database v semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "v()" open account semaphore */
  open_account_sem_buf.sem_num = 0;
  open_account_sem_buf.sem_op  = 1; /* "v()" */
  open_account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(open_account_sem_id, &open_account_sem_buf, 1) < 0) {
    perror("SERVER child process, open account v semop() failed %d\n");
    exit (1);
  }
#endif
}

/**************************************************************************
 * Deposit money in an account. The account id and access password are 
 * verified before the transaction is done.
 **************************************************************************/
void deposit(char *req_buf, char *resp_buf)
{
  int rtn;
  int temp, id, password, amount;
  account_t *accountp;

  /* Parse input string */
  sscanf(req_buf, "%d %d %d %d ", &temp, &id, &password, &amount);
  DPRINTF(("SERVER: deposit, id %d, password %d, amount %d\n", 
	 id, password, amount));
  
  /* Check inputs */
  if ((id < 0) || (id >= MAX_NUM_ACCOUNTS)) {
    DPRINTF(("SERVER: deposit, %s\n", ERR_MSG_BAD_ACCOUNT));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    ERR_MSG_BAD_ACCOUNT);
    return;
  }

#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "p()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = -1; /* "p()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER: child process, single database p semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "p()" account semaphore */
  account_sem_buf.sem_num = account_sem_array[id].sem_num;
  account_sem_buf.sem_op  = -1; /* "p()" */
  account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(account_sem_array[id].set_id, &account_sem_buf, 1) < 0) {
    perror("SERVER: child process, account sem p semop() failed %d\n");
    exit (1);
  }
#endif

  /* Retrieve account from database */
  if ((rtn = retrieve_account( id, &accountp)) < 0) {
    DPRINTF(("SERVER: deposit, retrieve_account failed %s\n", atm_err_tbl[-rtn]));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    atm_err_tbl[-rtn]);

  /* Check password */
  } else if (password != accountp->password)  {
    DPRINTF(("SERVER: deposit, %s\n", ERR_MSG_BAD_PASSWORD));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    ERR_MSG_BAD_PASSWORD);

  /* Add new balance */
  } else {
    (accountp->balance) += amount;

    /* Store back to database */
    if ((rtn = store_account(accountp)) < 0) {
      DPRINTF(("SERVER: deposit, store_account failed %s\n", atm_err_tbl[-rtn]));
      sprintf(resp_buf, "%d %d %d %s", 
	     TRANS_FAILURE, 
	    -1, 
	    -1,
	    atm_err_tbl[-rtn]);

    /* Everything OK */
    } else { 
      sprintf(resp_buf, "%d",
	      TRANS_SUCCESS);
    }
  }

#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "v()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = 1; /* "v()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER child process, single_database v semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "v()" account semaphore */
  account_sem_buf.sem_num = account_sem_array[id].sem_num;
  account_sem_buf.sem_op  = 1; /* "v()" */
  account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(account_sem_array[id].set_id, &account_sem_buf, 1) < 0) {
    perror("SERVER child process, account sem v semop() failed %d\n");
    exit (1);
  }
#endif

}

/************************************************************************** 
 * Remove money from an account. The account id and access password are 
 * verified, and sufficient funds must be available for the transaction
 * to proceed.
 **************************************************************************/
void withdraw(char *req_buf, char *resp_buf)
{
  int rtn;
  int temp, id, password, amount;
  account_t *accountp;

  /* Parse input string */
  sscanf(req_buf, "%d %d %d %d", &temp, &id, &password, &amount);
  DPRINTF(("SERVER: withdraw,  id %d, password %d, amount %d\n", 
	  id, password, amount));


  /* Check inputs */
  if ((id < 0) || (id >= MAX_NUM_ACCOUNTS)) {
    DPRINTF(("SERVER: withdraw, %s", ERR_MSG_BAD_ACCOUNT));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE,
	    ERR_MSG_BAD_ACCOUNT);
    return;
  }

#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "p()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = -1; /* "p()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER: child process, single database p semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "p()" account semaphore */
  account_sem_buf.sem_num = account_sem_array[id].sem_num;
  account_sem_buf.sem_op  = -1; /* "p()" */
  account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(account_sem_array[id].set_id, &account_sem_buf, 1) < 0) {
    perror("SERVER: child process, account sem p semop() failed %d\n");
    exit (1);
  }
#endif

  /* Retrieve account from database */
  if ((rtn = retrieve_account( id, &accountp)) < 0) {
    DPRINTF(("SERVER: withdraw, retrieve_account failed %s\n", 
	     atm_err_tbl[-rtn]));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    atm_err_tbl[-rtn]);

  /* Check password */
  } else if (password != accountp->password)  {
    DPRINTF(("SERVER: withdraw, %s\n", ERR_MSG_BAD_PASSWORD));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    ERR_MSG_BAD_PASSWORD);

  /* Check for funds */
  } else if (amount > accountp->balance) {
    DPRINTF(("SERVER: withdraw, %s\n", ERR_MSG_INS_FUNDS));
    return_account(accountp);
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    ERR_MSG_INS_FUNDS);

  /* Compute new balance */
  } else {
    accountp->balance -= amount;
    if ((rtn = store_account(accountp)) < 0) {
      DPRINTF(("SERVER: withdraw, store_account failed %s\n", atm_err_tbl[-rtn]));
      sprintf(resp_buf, "%d %d %d %s", 
	      TRANS_FAILURE, 
	      -1, 
	      -1,
	      atm_err_tbl[-rtn]);
    } else { 
      sprintf(resp_buf, "%d",
	      TRANS_SUCCESS);
    }
  }

#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "v()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = 1; /* "v()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER child process, single_database v semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "v()" account semaphore */
  account_sem_buf.sem_num = account_sem_array[id].sem_num;
  account_sem_buf.sem_op  = 1; /* "v()" */
  account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(account_sem_array[id].set_id, &account_sem_buf, 1) < 0) {
    perror("SERVER child process, account sem v semop() failed %d\n");
    exit (1);
  }
#endif

}

/************************************************************************** 
 * Provide the current balance in an account. Account id and access password
 * are verified.
 **************************************************************************/
void balance(char *req_buf, char *resp_buf)
{
  int rtn;
  int temp, id, password;
  int cur_bal;
  account_t *accountp;

  /* Parse input string */
  sscanf(req_buf, "%c %d %d", &temp, &id, &password);
  DPRINTF(("SERVER: balance, id %d, password %d\n", id, password));

  /* Check inputs */
  if ((id < 0) || (id >= MAX_NUM_ACCOUNTS)) {
    DPRINTF(("SERVER: balance, %s", ERR_MSG_BAD_ACCOUNT));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE,
	    ERR_MSG_BAD_ACCOUNT);
    return;
  }

#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "p()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = -1; /* "p()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER: child process, single database p semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "p()" account semaphore */
  account_sem_buf.sem_num = account_sem_array[id].sem_num;
  account_sem_buf.sem_op  = -1; /* "p()" */
  account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(account_sem_array[id].set_id, &account_sem_buf, 1) < 0) {
    perror("SERVER: child process, account sem p semop() failed %d\n");
    exit (1);
  }
#endif

  /* Retrieve account from database */
  if ((rtn = retrieve_account( id, &accountp)) < 0) {
    DPRINTF(("SERVER: balance, retrieve_account failed %s\n", 
	     atm_err_tbl[-rtn]));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    atm_err_tbl[-rtn]);


  } else { 

    /* Check password */
    if (password != accountp->password)  {
      DPRINTF(("SERVER: balance, %s\n", ERR_MSG_BAD_PASSWORD));
      sprintf(resp_buf, "%d %s",
	      TRANS_FAILURE, 
	      ERR_MSG_BAD_PASSWORD);
      
    } else {

      /* Get balance */
      cur_bal = accountp->balance;
      sprintf(resp_buf, "%d %d",
	      TRANS_SUCCESS,
	      cur_bal);
    }
    return_account(accountp);
  }
  
#ifdef NO_DATABASE_SYNC

#elif defined(SINGLE_DATABASE_SEM_SYNC)
  /* "v()" single database semaphore */
  single_database_sem_buf.sem_num = 0;
  single_database_sem_buf.sem_op  = 1; /* "v()" */
  single_database_sem_buf.sem_flg = SEM_UNDO;
  if (semop(single_database_sem_id, &single_database_sem_buf, 1) < 0) {
    perror("SERVER child process, single_database v semop() failed %d\n");
    exit (1);
  }
#elif defined(ACCOUNT_SEM_SYNC)
  /* "v()" account semaphore */
  account_sem_buf.sem_num = account_sem_array[id].sem_num;
  account_sem_buf.sem_op  = 1; /* "v()" */
  account_sem_buf.sem_flg = SEM_UNDO;
  if (semop(account_sem_array[id].set_id, &account_sem_buf, 1) < 0) {
    perror("SERVER child process, account sem v semop() failed %d\n");
    exit (1);
  }
#endif

}

/************************************************************************** 
 * Provide a means to remotely shutdown server.
 * Any valid account can do it under this simple scheme.
 **************************************************************************/
int shutdown_req(char *req_buf, char *resp_buf)
{
  int temp, password;
  
  /* Parse input string */
  sscanf(req_buf, "%d %d %d", &temp, &password);
  DPRINTF(("SERVER: shutdown, password %d\n", password));

  /* Check password */
  if (check_server_password(password) != 1) {
    DPRINTF(("SERVER: shutdown_req, %s\n", ERR_MSG_BAD_PASSWORD));
    sprintf(resp_buf, "%d %s",
	    TRANS_FAILURE, 
	    ERR_MSG_BAD_PASSWORD);
    return 0;
  } else {
    /* ok, go ahead */
    sprintf(resp_buf, "%d",
	    TRANS_SUCCESS);
    return 1;
  }
}


/************************************************************************** 
 * Respond to client when transaction is unrecognized.
 **************************************************************************/
void handle_bad_trans_id(char *req_buf, char *resp_buf)
{
  int trans_id;

  /* Parse input string */
  sscanf(req_buf, "%d ", &trans_id);
  DPRINTF(("SERVER: bad transaction id, trans id %d\n", trans_id));
  sprintf(resp_buf, "%d %s",
	  TRANS_FAILURE,
	  ERR_MSG_BAD_TRANSID);
}