netstr.c

/*
 * Part of Very Secure FTPd
 * Licence: GPL v2
 * Author: Chris Evans
 * netstr.c
 *
 * The netstr interface extends the standard string interface, adding
 * functions which can cope safely with building strings from the network,
 * and send them out too.
 */

#include "netstr.h"
#include "str.h"
#include "sysstr.h"
#include "utility.h"
#include "sysutil.h"

#pragma CHECKED_SCOPE on

int
str_netfd_alloc(struct vsf_session *p_sess : itype(_Ptr<struct vsf_session>), struct mystr *p_str : itype(_Ptr<struct mystr>), char term, char *p_readbuf : count(maxlen), unsigned int maxlen, str_netfd_read_t *p_peekfunc : itype(_Ptr<str_netfd_read_t>) , str_netfd_read_t *p_readfunc : itype(_Ptr<str_netfd_read_t>))
{
  int retval;
  unsigned int bytes_read;
  unsigned int i;
  _Array_ptr<char> p_readpos : bounds(p_readbuf, p_readbuf + maxlen) = p_readbuf;
  unsigned int left = maxlen;
  str_empty(p_str);
  while (1)
  {
    if (p_readpos + left != p_readbuf + maxlen)
    {
      bug("poor buffer accounting in str_netfd_alloc");
    }
    /* Did we hit the max? */
    if (left == 0)
    {
      return -1;
    }
    retval = (*p_peekfunc)(p_sess, p_readpos, left);
    if (vsf_sysutil_retval_is_error(retval))
    {
      die("vsf_sysutil_recv_peek");
    }
    else if (retval == 0)
    {
      return 0;
    }
    bytes_read = (unsigned int) retval;
    /* Search for the terminator */
    for (i=0; i < bytes_read; i++)
    {
      if (p_readpos[i] == term)
      {
        /* Got it! */
        i++;
        _Array_ptr<char> tmp_read_pos : count(i) = _Dynamic_bounds_cast<_Array_ptr<char>>(p_readpos, count(i));
        retval = (*p_readfunc)(p_sess, tmp_read_pos, i);
        if (vsf_sysutil_retval_is_error(retval) ||
            (unsigned int) retval != i)
        {
          die("vsf_sysutil_read_loop");
        }
        if (p_readpos[i - 1] != term)
        {
          die("missing terminator in str_netfd_alloc");
        }
        str_alloc_alt_term(p_str, p_readbuf, term, maxlen);
        return (int) i;
      }
    }
    /* Not found in this read chunk, so consume the data and re-loop */
    if (bytes_read > left)
    {
      bug("bytes_read > left in str_netfd_alloc");
    }
    left -= bytes_read;
    _Array_ptr<char> tmp_read_pos : count(bytes_read) = _Dynamic_bounds_cast<_Array_ptr<char>>(p_readpos, count(bytes_read));
    retval = (*p_readfunc)(p_sess, tmp_read_pos, bytes_read);
    if (vsf_sysutil_retval_is_error(retval) ||
        (unsigned int) retval != bytes_read)
    {
      die("vsf_sysutil_read_loop");
    }
    p_readpos += bytes_read;
  } /* END: while(1) */
}

int
str_netfd_write(const struct mystr *p_str : itype(_Ptr<const struct mystr>), int fd)
{
  int ret = 0;
  int retval;
  unsigned int str_len = str_getlen(p_str);
  if (str_len == 0)
  {
    bug("zero str_len in str_netfd_write");
  }
  retval = str_write_loop(p_str, fd);
  if (vsf_sysutil_retval_is_error(retval) || (unsigned int) retval != str_len)
  {
    ret = -1;
  }
  return ret;
}

int
str_netfd_read(struct mystr *p_str : itype(_Ptr<struct mystr>), int fd, unsigned int len)
{
  int retval;
  str_reserve(p_str, len);
  str_trunc(p_str, len);
  retval = str_read_loop(p_str, fd);
  if (vsf_sysutil_retval_is_error(retval) || (unsigned int) retval != len)
  {
    return -1;
  }
  return retval;
}