distri fuse: bump rlimit NOFILE (open files) to 398430 (Linux max)

This will fix the problem once and for all!

fixes #53

Author: stapelberg

cmd/distri/distri.go

@@ -4,15 +4,19 @@ import (
 	"context"
 	"flag"
 	"fmt"
+	"io/ioutil"
 	"log"
 	"net/http"
 	"os"
 	"runtime/pprof"
 	"runtime/trace"
+	"strconv"
+	"strings"
 	"sync"
 	"sync/atomic"
 
 	"github.com/distr1/distri/cmd/distri/internal/fuse"
+	"golang.org/x/sys/unix"
 	"golang.org/x/xerrors"
 
 	_ "github.com/distr1/distri/internal/oninterrupt"
@@ -27,6 +31,41 @@ var (
 	httpListen = flag.String("listen", "", "host:port to listen on for HTTP")
 )
 
+func bumpRlimitNOFILE() error {
+	// The smaller of the two is the highest which Linux will let us set:
+	// https://github.com/torvalds/linux/blob/2be7d348fe924f0c5583c6a805bd42cecda93104/kernel/sys.c#L1526-L1541
+	var fileMax, nrOpen uint64
+	{
+		b, err := ioutil.ReadFile("/proc/sys/fs/file-max")
+		if err != nil {
+			return err
+		}
+		fileMax, err = strconv.ParseUint(strings.TrimSpace(string(b)), 0, 64)
+		if err != nil {
+			return err
+		}
+	}
+	{
+		b, err := ioutil.ReadFile("/proc/sys/fs/nr_open")
+		if err != nil {
+			return err
+		}
+		nrOpen, err = strconv.ParseUint(strings.TrimSpace(string(b)), 0, 64)
+		if err != nil {
+			return err
+		}
+	}
+	max := fileMax
+	if nrOpen < max {
+		max = nrOpen
+	}
+	set := unix.Rlimit{
+		Max: max,
+		Cur: max,
+	}
+	return unix.Setrlimit(unix.RLIMIT_NOFILE, &set)
+}
+
 var atExit struct {
 	sync.Mutex
 	fns    []func() error
@@ -96,6 +135,9 @@ func main() {
 		"scaffold": {scaffold},
 		"install":  {install},
 		"fuse": {func(args []string) error {
+			if err := bumpRlimitNOFILE(); err != nil {
+				log.Printf("Warning: bumping RLIMIT_NOFILE failed: %v", err)
+			}
 			join, err := fuse.Mount(args)
 			if err != nil {
 				return err

pkgs/base-cloud/build.textproto

@@ -1,5 +1,5 @@
 source: "empty://"
-version: "1-4"
+version: "1-5"
 
 # This is the shortest and fastest way to build an empty package:
 dep: "bash"

pkgs/base-full/build.textproto

@@ -1,5 +1,5 @@
 source: "empty://"
-version: "3-9"
+version: "3-10"
 
 # This is the shortest and fastest way to build an empty package:
 dep: "bash"

pkgs/base-x11/build.textproto

@@ -1,5 +1,5 @@
 source: "empty://"
-version: "2-11"
+version: "2-12"
 
 # This is the shortest and fastest way to build an empty package:
 dep: "bash"

pkgs/base/build.textproto

@@ -1,5 +1,5 @@
 source: "empty://"
-version: "3-9"
+version: "3-10"
 
 # This is the shortest and fastest way to build an empty package:
 dep: "bash"

pkgs/debugfs/build.textproto

@@ -1,5 +1,5 @@
 source: "empty://"
-version: "1-8"
+version: "1-9"
 
 cherry_pick: "service.patch"
 

pkgs/distri1/build.textproto

@@ -1,6 +1,6 @@
 source: "distriroot://distri1-1.tar.gz"
 hash: ""
-version: "native-17"
+version: "native-18"
 
 gobuilder: <
   install: "./cmd/distri"