Adjust |ulimit -n| automatically, no bash required (#5586)

core/src/validator.rs

@@ -431,6 +431,45 @@ fn get_bank_forks(
     (bank_forks, bank_forks_info, leader_schedule_cache)
 }
 
+#[cfg(not(unix))]
+fn adjust_ulimit_nofile() {}
+
+#[cfg(unix)]
+fn adjust_ulimit_nofile() {
+    // Rocks DB likes to have many open files.  The default open file descriptor limit is
+    // usually not enough
+    let desired_nofile = 65000;
+
+    fn get_nofile() -> libc::rlimit {
+        let mut nofile = libc::rlimit {
+            rlim_cur: 0,
+            rlim_max: 0,
+        };
+        if unsafe { libc::getrlimit(libc::RLIMIT_NOFILE, &mut nofile) } != 0 {
+            warn!("getrlimit(RLIMIT_NOFILE) failed");
+        }
+        nofile
+    }
+
+    let mut nofile = get_nofile();
+    if nofile.rlim_cur < desired_nofile {
+        nofile.rlim_cur = desired_nofile;
+        if unsafe { libc::setrlimit(libc::RLIMIT_NOFILE, &nofile) } != 0 {
+            error!(
+                "Unable to increase the maximum open file descriptor limit to {}",
+                desired_nofile
+            );
+
+            if cfg!(target_os = "macos") {
+                error!("On mac OS you may need to run |sudo launchctl limit maxfiles 65536 200000| first");
+            }
+        }
+
+        nofile = get_nofile();
+    }
+    info!("Maximum open file descriptors: {}", nofile.rlim_cur);
+}
+
 pub fn new_banks_from_blocktree(
     blocktree_path: &Path,
     account_paths: Option<String>,
@@ -448,6 +487,8 @@ pub fn new_banks_from_blocktree(
 ) {
     let genesis_block = GenesisBlock::load(blocktree_path).expect("Failed to load genesis block");
 
+    adjust_ulimit_nofile();
+
     let (blocktree, ledger_signal_receiver, completed_slots_receiver) =
         Blocktree::open_with_signal(blocktree_path).expect("Failed to open ledger database");
 

scripts/tune-system.sh

@@ -3,9 +3,6 @@
 # Adjusts system settings for optimal fullnode performance
 #
 
-# shellcheck source=scripts/ulimit-n.sh
-source "$(dirname "${BASH_SOURCE[0]}")"/ulimit-n.sh
-
 sysctl_write() {
   declare name=$1
   declare new_value=$2