Apply Go 1.12/Darwin file descriptor fix

Also: Improve some error reporting.

.gitignore

@@ -1,34 +1,10 @@
-# Compiled Object files, Static and Dynamic libs (Shared Objects)
-*.o
-*.a
-*.so
-
-# Folders
-_obj
-_test
-
-# Architecture specific extensions/prefixes
-*.[568vq]
-[568vq].out
-
-*.cgo1.go
-*.cgo2.c
-_cgo_defun.c
-_cgo_gotypes.go
-_cgo_export.*
-
-_testmain.go
-
-*.exe
-*.test
-*.prof
-*.iml
-*.cov
-
 config/
 build/
 test_data/
 test/
 deploy/
 .tags*
-profile.tmp
+*~
+profile.tmp
+*.cov
+.DS_Store

go.mod

@@ -15,6 +15,7 @@ require (
 	go.dedis.ch/protobuf v1.0.6
 	go.etcd.io/bbolt v1.3.2
 	golang.org/x/net v0.0.0-20190125091013-d26f9f9a57f3 // indirect
+	golang.org/x/sys v0.0.0-20190124100055-b90733256f2e
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/satori/go.uuid.v1 v1.2.0
 	gopkg.in/tylerb/graceful.v1 v1.2.15

simul/platform/deterlab.go

@@ -215,7 +215,7 @@ func (d *Deterlab) Cleanup() error {
 
 		err := SSHRunStdout(d.Login, d.Host, "test -f remote/users && ( cd remote; ./users -kill )")
 		if err != nil {
-			log.Lvl1("NOT-Normal error from cleanup")
+			log.Lvl1("NOT-Normal error from cleanup", err.Error())
 			sshKill <- "error"
 		}
 		sshKill <- "stopped"

simul/platform/fd_darwin.go

@@ -0,0 +1,62 @@
+package platform
+
+import (
+	"errors"
+	"syscall"
+
+	"go.dedis.ch/onet/v3/log"
+	"golang.org/x/sys/unix"
+)
+
+func init() {
+	var rLimit syscall.Rlimit
+	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+	if err != nil {
+		log.Fatal("Error Getting Rlimit ", err)
+	}
+
+	// We observed that with Go 1.11.5, we were getting
+	// 24576, and then with Go 1.12, we started getting "invalid argument".
+	// See https://github.com/golang/go/issues/30401
+
+	// On Darwin, the real fd max is given by sysctl.
+	res, err := unix.Sysctl("kern.maxfilesperproc")
+	if err != nil || len(res) != 3 {
+		// In case of error, fall back to something reasonable.
+		res = "10240"
+	}
+	// res is type string, but according to sysctl(3), it should be interpreted
+	// as an int32. It seems to be little-endian. And for some reason, there are only
+	// 3 bytes.
+	rLimit.Max = uint64(res[0]) | uint64(res[1])<<8 | uint64(res[2])<<16
+
+	if rLimit.Cur < rLimit.Max {
+		rLimit.Cur = rLimit.Max
+		err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+		if err != nil {
+			log.Warn("Error Setting Rlimit:", err)
+		}
+	}
+
+	err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rLimit)
+	log.Info("File descriptor limit is:", rLimit.Cur)
+}
+
+// CheckOutOfFileDescriptors tries to duplicate the stdout file descriptor
+// and throws an error if it cannot do it. This is a horrible hack mainly for
+// MacOSX where the file descriptor limit is quite low and we need to tell
+// people running simulations what they can do about it.
+func CheckOutOfFileDescriptors() error {
+	// Check if we're out of file descriptors
+	newFS, err := syscall.Dup(syscall.Stdout)
+	if err != nil {
+		return errors.New(`Out of file descriptors. You might want to do something like this for Mac OSX:
+    sudo sysctl -w kern.maxfiles=122880
+    sudo sysctl -w kern.maxfilesperproc=102400
+    sudo sysctl -w kern.ipc.somaxconn=20480`)
+	}
+	if err = syscall.Close(newFS); err != nil {
+		return errors.New("Couldn't close new file descriptor: " + err.Error())
+	}
+	return nil
+}

simul/platform/fd_unix.go

@@ -1,4 +1,4 @@
-// +build !windows
+// +build !windows,!darwin
 
 package platform
 

simul/platform/platform.go

@@ -150,8 +150,10 @@ func ReadRunFile(p Platform, filename string) []*RunConfig {
 	// Decoding of the first part of the run config file
 	// where the config wont change for the whole set of the simulation's tests
 	scanner := bufio.NewScanner(file)
+	line := 0
 	for scanner.Scan() {
 		text := scanner.Text()
+		line++
 		log.Lvl3("Decoding", text)
 		// end of the first part
 		if text == "" {
@@ -164,7 +166,7 @@ func ReadRunFile(p Platform, filename string) []*RunConfig {
 		// checking if format is good
 		vals := strings.Split(text, "=")
 		if len(vals) != 2 {
-			log.Fatal("Simulation file:", filename, " is not properly formatted ( key = value )")
+			log.Fatal("Simulation file:", filename, "line", line, "is not properly formatted ( key = value )")
 		}
 		// fill in the general config
 		masterConfig.Put(strings.TrimSpace(vals[0]), strings.TrimSpace(vals[1]))