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/*
* timer_create.c - create a per-process timer.
*/
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/syscall.h>
#include "kernel-posix-timers.h"
#ifdef __NR_timer_create
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#define __NR___syscall_timer_create __NR_timer_create
static inline _syscall3(int, __syscall_timer_create, clockid_t, clock_id,
struct sigevent *, evp, kernel_timer_t *, ktimerid);
/* Create a per-process timer */
int timer_create(clockid_t clock_id, struct sigevent *evp, timer_t *timerid)
{
int retval;
kernel_timer_t ktimerid;
struct sigevent local_evp;
struct timer *newp;
/* Notification via a thread is not supported yet */
if (__builtin_expect(evp->sigev_notify == SIGEV_THREAD, 1))
return -1;
/*
* We avoid allocating too much memory by basically using
* struct timer as a derived class with the first two elements
* being in the superclass. We only need these two elements here.
*/
newp = (struct timer *) malloc(offsetof(struct timer, thrfunc));
if (newp == NULL)
return -1; /* No memory */
if (evp == NULL) {
/*
* The kernel has to pass up the timer ID which is a userlevel object.
* Therefore we cannot leave it up to the kernel to determine it.
*/
local_evp.sigev_notify = SIGEV_SIGNAL;
local_evp.sigev_signo = SIGALRM;
local_evp.sigev_value.sival_ptr = newp;
evp = &local_evp;
}
retval = __syscall_timer_create(clock_id, evp, &ktimerid);
if (retval != -1) {
newp->sigev_notify = (evp != NULL ? evp->sigev_notify : SIGEV_SIGNAL);
newp->ktimerid = ktimerid;
*timerid = (timer_t) newp;
} else {
/* Cannot allocate the timer, fail */
free(newp);
retval = -1;
}
return retval;
}
#endif
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