From a79afd9ac325e12021ae56928ba4af32bb3cc78f Mon Sep 17 00:00:00 2001
From: Olivier H <olivier.hervieu@gmail.com>
Date: Mon, 7 Mar 2022 09:21:06 +0100
Subject: [PATCH] cmd: allow file descriptor limit to be set via CLI (#24477)
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* eth, cmd: allow FdLimit to be set in config/command line (#24148)

* eth/ethconfig: format code

* cmd, eth/ethconfig: simplify fdlimit arg, disallow toml

* cnd/utils: make fdlimit setting nicer on the logs

Co-authored-by: Gary Rong <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>
---
 cmd/geth/main.go   |  1 +
 cmd/geth/usage.go  |  1 +
 cmd/utils/flags.go | 23 ++++++++++++++++++++---
 3 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index 288ff28ef..816260862 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -118,6 +118,7 @@ var (
 		utils.CacheSnapshotFlag,
 		utils.CacheNoPrefetchFlag,
 		utils.CachePreimagesFlag,
+		utils.FDLimitFlag,
 		utils.ListenPortFlag,
 		utils.MaxPeersFlag,
 		utils.MaxPendingPeersFlag,
diff --git a/cmd/geth/usage.go b/cmd/geth/usage.go
index 637810769..a2d278118 100644
--- a/cmd/geth/usage.go
+++ b/cmd/geth/usage.go
@@ -119,6 +119,7 @@ var AppHelpFlagGroups = []flags.FlagGroup{
 			utils.CacheSnapshotFlag,
 			utils.CacheNoPrefetchFlag,
 			utils.CachePreimagesFlag,
+			utils.FDLimitFlag,
 		},
 	},
 	{
diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index c1d226df0..7880bee21 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -433,6 +433,10 @@ var (
 		Name:  "cache.preimages",
 		Usage: "Enable recording the SHA3/keccak preimages of trie keys",
 	}
+	FDLimitFlag = cli.IntFlag{
+		Name:  "fdlimit",
+		Usage: "Raise the open file descriptor resource limit (default = system fd limit)",
+	}
 	// Miner settings
 	MiningEnabledFlag = cli.BoolFlag{
 		Name:  "mine",
@@ -1071,11 +1075,24 @@ func setLes(ctx *cli.Context, cfg *ethconfig.Config) {
 
 // MakeDatabaseHandles raises out the number of allowed file handles per process
 // for Geth and returns half of the allowance to assign to the database.
-func MakeDatabaseHandles() int {
+func MakeDatabaseHandles(max int) int {
 	limit, err := fdlimit.Maximum()
 	if err != nil {
 		Fatalf("Failed to retrieve file descriptor allowance: %v", err)
 	}
+	switch {
+	case max == 0:
+		// User didn't specify a meaningful value, use system limits
+	case max < 128:
+		// User specified something unhealthy, just use system defaults
+		log.Error("File descriptor limit invalid (<128)", "had", max, "updated", limit)
+	case max > limit:
+		// User requested more than the OS allows, notify that we can't allocate it
+		log.Warn("Requested file descriptors denied by OS", "req", max, "limit", limit)
+	default:
+		// User limit is meaningful and within allowed range, use that
+		limit = max
+	}
 	raised, err := fdlimit.Raise(uint64(limit))
 	if err != nil {
 		Fatalf("Failed to raise file descriptor allowance: %v", err)
@@ -1540,7 +1557,7 @@ func SetEthConfig(ctx *cli.Context, stack *node.Node, cfg *ethconfig.Config) {
 	if ctx.GlobalIsSet(CacheFlag.Name) || ctx.GlobalIsSet(CacheDatabaseFlag.Name) {
 		cfg.DatabaseCache = ctx.GlobalInt(CacheFlag.Name) * ctx.GlobalInt(CacheDatabaseFlag.Name) / 100
 	}
-	cfg.DatabaseHandles = MakeDatabaseHandles()
+	cfg.DatabaseHandles = MakeDatabaseHandles(ctx.GlobalInt(FDLimitFlag.Name))
 	if ctx.GlobalIsSet(AncientFlag.Name) {
 		cfg.DatabaseFreezer = ctx.GlobalString(AncientFlag.Name)
 	}
@@ -1858,7 +1875,7 @@ func SplitTagsFlag(tagsFlag string) map[string]string {
 func MakeChainDatabase(ctx *cli.Context, stack *node.Node, readonly bool) ethdb.Database {
 	var (
 		cache   = ctx.GlobalInt(CacheFlag.Name) * ctx.GlobalInt(CacheDatabaseFlag.Name) / 100
-		handles = MakeDatabaseHandles()
+		handles = MakeDatabaseHandles(ctx.GlobalInt(FDLimitFlag.Name))
 
 		err     error
 		chainDb ethdb.Database