src/select/select.c

#include <sys/select.h>
#include <signal.h>
#include <stdint.h>
#include <errno.h>
#include "syscall.h"
#include "libc.h"

int select(int n, fd_set *restrict rfds, fd_set *restrict wfds, fd_set *restrict efds, struct timeval *restrict tv)
{
#ifdef SYS_select
	return syscall_cp(SYS_select, n, rfds, wfds, efds, tv);
#else
	syscall_arg_t data[2] = { 0, _NSIG/8 };
	struct timespec ts;
	if (tv) {
		if (tv->tv_sec < 0 || tv->tv_usec < 0)
			return __syscall_ret(-EINVAL);
		time_t extra_secs = tv->tv_usec / 1000000;
		ts.tv_nsec = tv->tv_usec % 1000000 * 1000;
		const time_t max_time = (1ULL<<8*sizeof(time_t)-1)-1;
		ts.tv_sec = extra_secs > max_time - tv->tv_sec ?
			max_time : tv->tv_sec + extra_secs;
	}
	return syscall_cp(SYS_pselect6, n, rfds, wfds, efds, tv ? &ts : 0, data);
#endif
}