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#ident "$Id: io.c,v 4.3 2014/01/28 13:42:57 gert Exp $ Copyright (c) Gert Doering"
/* io.c
*
* This module contains a few low-level I/O functions
* (will be extended)
*/
#include <stdio.h>
#include <unistd.h>
#include "syslibs.h"
#include <signal.h>
#include <errno.h>
#include "mgetty.h"
/* warning: these includes have to appear *after* "mgetty.h"! */
#ifdef USE_POLL
# include <poll.h>
# if !defined(_AIX) && !defined(BSD)
int poll _PROTO(( struct pollfd fds[], unsigned long nfds, int timeout ));
# endif /* AIX / Linux */
#endif /* USE_POLL */
/* SCO Unix defines XENIX as well, which will confuse the code below */
#if defined(M_XENIX) && defined(M_UNIX)
# undef M_XENIX
#endif
#ifdef USE_SELECT
# include <string.h>
# if defined (linux) || defined (sunos4) || defined (SVR4) || \
defined (__hpux) || defined (MEIBE) || defined(sgi) || \
defined (ISC) || defined (BSD) || defined(sysV68) || \
defined(m88k) || defined(M_XENIX)
# include <sys/types.h>
# include <sys/time.h>
# ifdef ISC
# include <sys/bsdtypes.h>
# endif /* ISC */
# ifdef M_XENIX
# include <sys/select.h>
# endif
# else /* not sys/types.h + sys/time.h */
# include <sys/select.h>
# endif
# ifdef NEED_BZERO
# define bzero( ptr, length ) memset( ptr, 0, length )
# endif
#endif /* USE_SELECT */
void delay _P1( (waittime),
int waittime ) /* wait waittime milliseconds */
{
#ifdef USE_USLEEP
usleep( waittime * 1000 );
#else
#ifdef USE_POLL
struct pollfd sdummy;
poll( &sdummy, 0, waittime );
#else
#ifdef USE_NAP
nap( (long) waittime );
#else
#ifdef USE_SELECT
struct timeval s;
s.tv_sec = waittime / 1000;
s.tv_usec = (waittime % 1000) * 1000;
select( 0, (fd_set *) NULL, (fd_set *) NULL, (fd_set *) NULL, &s );
#else /* neither poll nor nap nor select available */
if ( waittime < 2000 ) waittime = 2000; /* round up */
sleep( waittime / 1000); /* a sleep of 1 may not sleep at all */
#endif /* use select */
#endif /* use nap */
#endif /* use poll */
#endif /* use usleep */
}
/* check_for_input( open file deskriptor )
*
* returns TRUE if there's something to read on filedes, FALSE otherwise
*/
boolean check_for_input _P1( (filedes),
int filedes )
{
#ifdef USE_SELECT
fd_set readfds;
struct timeval timeout;
#endif
#ifdef USE_POLL
struct pollfd fds;
#endif
int ret;
#ifdef USE_SELECT
FD_ZERO( &readfds );
FD_SET( filedes, &readfds );
timeout.tv_sec = timeout.tv_usec = 0;
ret = select( FD_SETSIZE , &readfds, NULL, NULL, &timeout );
#else
# ifdef USE_POLL
fds.fd = filedes;
fds.events = POLLIN;
fds.revents= 0;
ret = poll( &fds, 1, 0 );
# else
ret = 0; /* CHEAT! */
# endif
#endif
if ( ret < 0 ) lprintf( L_ERROR, "poll / select failed" );
return ( ret > 0 );
}
#if !defined( USE_SELECT) && !defined( USE_POLL )
static RETSIGTYPE wfi_timeout(SIG_HDLR_ARGS) {}
#endif
/* wait until a character is available
* where select() or poll() exists, no characters will be read,
* if only read() can be used, at least one character will be dropped
*
* return TRUE if data is found, FALSE if "msecs" milliseconds have passed
*/
boolean wait_for_input _P2( (fd, msecs), int fd, int msecs )
{
#ifdef USE_SELECT
fd_set readfds;
struct timeval timeout, *tptr;
#endif
#ifdef USE_POLL
struct pollfd fds;
int timeout;
#endif
int slct;
#ifdef USE_SELECT
FD_ZERO( &readfds );
FD_SET( fd, &readfds );
if ( msecs >= 0 )
{
timeout.tv_sec = msecs / 1000;
timeout.tv_usec = (msecs % 1000) * 1000; /* microsecs! */
tptr = &timeout;
}
else
tptr = NULL;
slct = select( FD_SETSIZE, &readfds, NULL, NULL, tptr );
lprintf( L_JUNK, "select returned %d", slct );
#else /* use poll */
# ifdef USE_POLL
if ( msecs < 0 ) timeout = -1;
else timeout = msecs;
fds.fd = fd;
fds.events = POLLIN;
fds.revents= 0;
slct = poll( &fds, 1, timeout );
lprintf( L_JUNK, "poll returned %d", slct );
# else
{
char t;
int oerrno;
if ( msecs > 0 )
{
signal( SIGALRM, wfi_timeout );
alarm( (msecs+999)/1000 );
}
slct = read( fd, &t, 1 );
oerrno = errno;
alarm(0); signal( SIGALRM, SIG_DFL );
errno = oerrno;
if ( slct < 0 )
{
if ( errno == EINTR )
lprintf( L_JUNK, "read: timeout" );
else
lprintf( L_ERROR, "read: error" );
}
else
{
lprintf(L_JUNK, "read returned: "); lputc(L_JUNK, t );
}
}
# endif
#endif
return ( slct>0 );
}
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