#include <signal.h>
#include <errno.h>
#include "syscall.h"

int sigaltstack(const stack_t* restrict ss, stack_t* restrict old) {
  if (ss) {
    if (ss->ss_size < MINSIGSTKSZ) {
      errno = ENOMEM;
      return -1;
    }
    if (ss->ss_flags & ~SS_DISABLE) {
      errno = EINVAL;
      return -1;
    }
  }
  return syscall(SYS_sigaltstack, ss, old);
}