On 6/17/24 03:43, Andreas Schwab wrote:
$ cat select.c
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/resource.h>
#include <sys/select.h>
#include <sys/syscall.h>
int
main (int argc, char **argv)
{
int nfds = (argc > 1 ? atoi (argv[1]) : 1031);
fd_set *fds = calloc ((nfds + (sizeof (fd_mask) * 8) - 1)
/ (sizeof (fd_mask) * 8), sizeof (fd_mask));
setrlimit (RLIMIT_NOFILE,
&(struct rlimit){ .rlim_cur = nfds, .rlim_max = nfds });
dup2 (open ("/dev/null", O_RDONLY), nfds - 1);
FD_SET (nfds - 1, fds);
syscall (SYS_pselect6, nfds, fds, 0, 0, 0, 0);
}
Ack.
We use libc fd_set, which is sized for FD_SETSIZE at 1024.
We can either artificially limit RLIMIT_NOFILE (not ideal), or dynamically allocate all
fd_set within qemu (which will take some time and effort).
r~
