select.c raw

   1  #include <sys/select.h>
   2  #include <signal.h>
   3  #include <stdint.h>
   4  #include <errno.h>
   5  #include "syscall.h"
   6  
   7  #define IS32BIT(x) !((x)+0x80000000ULL>>32)
   8  #define CLAMP(x) (int)(IS32BIT(x) ? (x) : 0x7fffffffU+((0ULL+(x))>>63))
   9  
  10  int select(int n, fd_set *restrict rfds, fd_set *restrict wfds, fd_set *restrict efds, struct timeval *restrict tv)
  11  {
  12  	time_t s = tv ? tv->tv_sec : 0;
  13  	suseconds_t us = tv ? tv->tv_usec : 0;
  14  	long ns;
  15  	const time_t max_time = (1ULL<<8*sizeof(time_t)-1)-1;
  16  
  17  	if (s<0 || us<0) return __syscall_ret(-EINVAL);
  18  	if (us/1000000 > max_time - s) {
  19  		s = max_time;
  20  		us = 999999;
  21  		ns = 999999999;
  22  	} else {
  23  		s += us/1000000;
  24  		us %= 1000000;
  25  		ns = us*1000;
  26  	}
  27  
  28  #ifdef SYS_pselect6_time64
  29  	int r = -ENOSYS;
  30  	if (SYS_pselect6 == SYS_pselect6_time64 || !IS32BIT(s))
  31  		r = __syscall_cp(SYS_pselect6_time64, n, rfds, wfds, efds,
  32  			tv ? ((long long[]){s, ns}) : 0,
  33  			((syscall_arg_t[]){ 0, _NSIG/8 }));
  34  	if (SYS_pselect6 == SYS_pselect6_time64 || r!=-ENOSYS)
  35  		return __syscall_ret(r);
  36  #endif
  37  #ifdef SYS_select
  38  	return syscall_cp(SYS_select, n, rfds, wfds, efds,
  39  		tv ? ((long[]){s, us}) : 0);
  40  #else
  41  	return syscall_cp(SYS_pselect6, n, rfds, wfds, efds,
  42  		tv ? ((long[]){s, ns}) : 0, ((syscall_arg_t[]){ 0, _NSIG/8 }));
  43  #endif
  44  }
  45