minix/lib/nbsd_libc/sys-minix/nanosleep.c
Gianluca Guida 4f294c247f Add NBSDLibc Minix specific files.
This patch mainly copies and modifies files existing in
the current libc implementing minix specific functions.

To keep consisten with the NetBSD libc, we remove 
namespace stubs and we use "namespace.h" and weak
links.
2011-02-17 17:11:09 +00:00

92 lines
1.9 KiB
C

/* nanosleep() - Sleep for a number of seconds. Author: Erik van der Kouwe
* 25 July 2009
*/
#include <sys/cdefs.h>
#include "namespace.h"
#include <lib.h>
#include <unistd.h>
#include <errno.h>
#include <time.h>
#include <sys/select.h>
#include <sys/time.h>
#define MSEC_PER_SEC 1000
#define USEC_PER_MSEC 1000
#define NSEC_PER_USEC 1000
#define USEC_PER_SEC (USEC_PER_MSEC * MSEC_PER_SEC)
#define NSEC_PER_SEC (NSEC_PER_USEC * USEC_PER_SEC)
int nanosleep(const struct timespec *rqtp, struct timespec *rmtp)
{
struct timeval timeout, timestart = { 0, 0 }, timeend;
int errno_select, r;
struct timespec rqt;
/* check parameters */
if (!rqtp)
return EFAULT;
if (rqtp->tv_sec < 0 ||
rqtp->tv_nsec < 0 ||
rqtp->tv_nsec >= NSEC_PER_SEC)
return EINVAL;
/* store *rqtp to make sure it is not overwritten */
rqt = *rqtp;
/* keep track of start time if needed */
if (rmtp)
{
rmtp->tv_sec = 0;
rmtp->tv_nsec = 0;
if (gettimeofday(&timestart, NULL) < 0)
return -1;
}
/* use select to wait */
timeout.tv_sec = rqt.tv_sec;
timeout.tv_usec = (rqt.tv_nsec + NSEC_PER_USEC - 1) / NSEC_PER_USEC;
r = select(0, NULL, NULL, NULL, &timeout);
/* return remaining time only if requested */
/* if select succeeded then we slept all time */
if (!rmtp || r >= 0)
return r;
/* measure end time; preserve errno */
errno_select = errno;
if (gettimeofday(&timeend, NULL) < 0)
return -1;
errno = errno_select;
/* compute remaining time */
rmtp->tv_sec = rqt.tv_sec - (timeend.tv_sec - timestart.tv_sec);
rmtp->tv_nsec = rqt.tv_nsec - (timeend.tv_usec - timestart.tv_usec) * NSEC_PER_USEC;
/* bring remaining time into canonical form */
while (rmtp->tv_nsec < 0)
{
rmtp->tv_sec -= 1;
rmtp->tv_nsec += NSEC_PER_SEC;
}
while (rmtp->tv_nsec > NSEC_PER_SEC)
{
rmtp->tv_sec += 1;
rmtp->tv_nsec -= NSEC_PER_SEC;
}
/* remaining time must not be negative */
if (rmtp->tv_sec < 0)
{
rmtp->tv_sec = 0;
rmtp->tv_nsec = 0;
}
return r;
}