sfpkrd.c revision 3e14f97f673e8a630f076077de35afdd43dc1587
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/***********************************************************************
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* This software is part of the ast package *
3e14f97f673e8a630f076077de35afdd43dc1587Roger A. Faulkner* Copyright (c) 1985-2010 AT&T Intellectual Property *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* and is licensed under the *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Common Public License, Version 1.0 *
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin* by AT&T Intellectual Property *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* A copy of the License is available at *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Information and Software Systems Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* AT&T Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Florham Park NJ *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Glenn Fowler <gsf@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* David Korn <dgk@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Phong Vo <kpv@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin***********************************************************************/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/* Read/Peek a record from an unseekable device
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** Written by Kiem-Phong Vo.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinssize_t sfpkrd(int fd, Void_t* argbuf, size_t n, int rc, long tm, int action)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinint action; /* >0: peeking, if rc>=0, get action records,
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin <0: no peeking, if rc>=0, get -action records,
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin =0: no peeking, if rc>=0, must get a single record
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin t = (action > 0 || rc >= 0) ? (STREAM_PEEK|SOCKET_PEEK) : 0;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r == 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if(r > 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif /* stream_peek */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* poll or select to see if data is present. */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* block until there is data before peeking again */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* let select be interrupted instead of recv which autoresumes */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r == -2)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else r = -2;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif /*_lib_poll*/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r == -2)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else r = -2;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif /*_lib_select*/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r == -2)
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin#if !_lib_poll && !_lib_select /* both poll and select can't be used */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#ifdef FIONREAD /* quick and dirty check for availability */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin while(nsec > 0 && r < 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else /* ioctl failed completely */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r < 0 && nsec-- > 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r > 0) /* there is data now */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else r = -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else r = -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin * work around macos 10.4 recv(MSG_PEEK) bug that consumes pipe() data
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin recv_peek_ok = (!pipe(fds) && write(fds[1], tst, 2) && recv(fds[0], tst, 1, MSG_PEEK) == 1 && tst[0] == 'a' && recv(fds[0], tst, 1, MSG_PEEK) == 1 && tst[0] == 'a') ? 1 : -1;
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin if (recv_peek_ok < 0 && !fstat(fd, &st) && !S_ISSOCK(st.st_mode))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r >= 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else /* read past eof */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return -1;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else /* get here means: tm < 0 && action <= 0 && rc >= 0 */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* number of records read at a time */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin return r == 0 ? t : r;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* successful peek, find the record end */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if((t -= 1) == 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* advance */