src/tools/compiletest/src/raise_fd_limit.rs

   1 /// darwin_fd_limit exists to work around an issue where launchctl on macOS
   2 /// defaults the rlimit maxfiles to 256/unlimited. The default soft limit of 256
   3 /// ends up being far too low for our multithreaded scheduler testing, depending
   4 /// on the number of cores available.
   5 ///
   6 /// This fixes issue #7772.
   7 #[cfg(any(target_os = "macos", target_os = "ios", target_os = "watchos"))]
   8 #[allow(non_camel_case_types)]
   9 pub unsafe fn raise_fd_limit() {
  10     use std::cmp;
  11     use std::io;
  12     use std::mem::size_of_val;
  13     use std::ptr::null_mut;
  14
  15     static CTL_KERN: libc::c_int = 1;
  16     static KERN_MAXFILESPERPROC: libc::c_int = 29;
  17
  18     // The strategy here is to fetch the current resource limits, read the
  19     // kern.maxfilesperproc sysctl value, and bump the soft resource limit for
  20     // maxfiles up to the sysctl value.
  21
  22     // Fetch the kern.maxfilesperproc value
  23     let mut mib: [libc::c_int; 2] = [CTL_KERN, KERN_MAXFILESPERPROC];
  24     let mut maxfiles: libc::c_int = 0;
  25     let mut size: libc::size_t = size_of_val(&maxfiles) as libc::size_t;
  26     if libc::sysctl(&mut mib[0], 2, &mut maxfiles as *mut _ as *mut _, &mut size, null_mut(), 0)
  27         != 0
  28     {
  29         let err = io::Error::last_os_error();
  30         panic!("raise_fd_limit: error calling sysctl: {}", err);
  31     }
  32
  33     // Fetch the current resource limits
  34     let mut rlim = libc::rlimit { rlim_cur: 0, rlim_max: 0 };
  35     if libc::getrlimit(libc::RLIMIT_NOFILE, &mut rlim) != 0 {
  36         let err = io::Error::last_os_error();
  37         panic!("raise_fd_limit: error calling getrlimit: {}", err);
  38     }
  39
  40     // Make sure we're only ever going to increase the rlimit.
  41     if rlim.rlim_cur < maxfiles as libc::rlim_t {
  42         // Bump the soft limit to the smaller of kern.maxfilesperproc and the hard limit.
  43         rlim.rlim_cur = cmp::min(maxfiles as libc::rlim_t, rlim.rlim_max);
  44
  45         // Set our newly-increased resource limit.
  46         if libc::setrlimit(libc::RLIMIT_NOFILE, &rlim) != 0 {
  47             let err = io::Error::last_os_error();
  48             panic!("raise_fd_limit: error calling setrlimit: {}", err);
  49         }
  50     }
  51 }
  52
  53 #[cfg(not(any(target_os = "macos", target_os = "ios")))]
  54 pub unsafe fn raise_fd_limit() {}