Merge pull request #54 from giuseppe/fix-auxv-enoent

host: use /proc/self/auxv only when not using cgo

Makefile

@@ -1,3 +1,5 @@
+export GO111MODULE=off
+
 SHELL= /bin/bash
 GO ?= go
 BUILD_DIR := ./bin
@@ -51,7 +53,7 @@ install:
 .PHONY: .install.lint
 .install.lint:
 	# Workaround for https://github.com/golangci/golangci-lint/issues/523
-	go get -u github.com/golangci/golangci-lint/cmd/golangci-lint@master
+	go get -u github.com/golangci/golangci-lint/cmd/golangci-lint
 
 .PHONY: uninstall
 uninstall:

internal/host/host.go

@@ -18,73 +18,12 @@ package host
 
 import (
 	"bufio"
-	"encoding/binary"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
-	"unsafe"
 )
 
-var (
-	// cache host queries to redundant calculations
-	clockTicks *int64
-	bootTime   *int64
-)
-
-func getNativeEndianness() binary.ByteOrder {
-	var i int32 = 0x00000001
-	u := unsafe.Pointer(&i)
-	if *((*byte)(u)) == 0x01 {
-		return binary.LittleEndian
-	}
-	return binary.BigEndian
-}
-
-const (
-	atClktck = 17
-)
-
-func getFromAuxv(what uint, whatName string) (uint, error) {
-	dataLen := int(unsafe.Sizeof(int(0)))
-	p, err := ioutil.ReadFile("/proc/self/auxv")
-	if err != nil {
-		return 0, err
-	}
-	native := getNativeEndianness()
-	for i := 0; i < len(p); {
-		var k, v uint
-
-		switch dataLen {
-		case 4:
-			k = uint(native.Uint32(p[i : i+dataLen]))
-			v = uint(native.Uint32(p[i+dataLen : i+dataLen*2]))
-		case 8:
-			k = uint(native.Uint64(p[i : i+dataLen]))
-			v = uint(native.Uint64(p[i+dataLen : i+dataLen*2]))
-		}
-		i += dataLen * 2
-		if k == what {
-			return v, nil
-		}
-	}
-	return 0, fmt.Errorf("cannot find %s in auxv", whatName)
-}
-
-// ClockTicks returns sysconf(SC_CLK_TCK).
-func ClockTicks() (int64, error) {
-	if clockTicks == nil {
-		ret, err := getFromAuxv(atClktck, "AT_CLKTCK")
-		if err != nil {
-			return -1, err
-		}
-		ticks := int64(ret)
-		clockTicks = &ticks
-	}
-	return *clockTicks, nil
-}
-
 // BootTime parses /proc/uptime returns the boot time in seconds since the
 // Epoch, 1970-01-01 00:00:00 +0000 (UTC).
 func BootTime() (int64, error) {

internal/host/host_cgo.go

@@ -0,0 +1,37 @@
+// Copyright 2018 psgo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package host extracts data from the host, such as the system's boot time or
+// the tick rate of the system clock.
+package host
+
+/*
+#include <unistd.h>
+*/
+import "C"
+
+var (
+	// cache host queries to redundant calculations
+	clockTicks *int64
+	bootTime   *int64
+)
+
+// ClockTicks returns sysconf(SC_CLK_TCK).
+func ClockTicks() (int64, error) {
+	if clockTicks == nil {
+		ticks := int64(C.sysconf(C._SC_CLK_TCK))
+		clockTicks = &ticks
+	}
+	return *clockTicks, nil
+}

internal/host/host_nocgo.go

@@ -0,0 +1,84 @@
+// +build !cgo
+
+// Copyright 2018 psgo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package host extracts data from the host, such as the system's boot time or
+// the tick rate of the system clock.
+package host
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io/ioutil"
+	"unsafe"
+)
+
+var (
+	// cache host queries to redundant calculations
+	clockTicks *int64
+	bootTime   *int64
+)
+
+func getNativeEndianness() binary.ByteOrder {
+	var i int32 = 0x00000001
+	u := unsafe.Pointer(&i)
+	if *((*byte)(u)) == 0x01 {
+		return binary.LittleEndian
+	}
+	return binary.BigEndian
+}
+
+const (
+	atClktck = 17
+)
+
+func getFromAuxv(what uint, whatName string) (uint, error) {
+	dataLen := int(unsafe.Sizeof(int(0)))
+	p, err := ioutil.ReadFile("/proc/self/auxv")
+	if err != nil {
+		return 0, err
+	}
+	native := getNativeEndianness()
+	for i := 0; i < len(p); {
+		var k, v uint
+
+		switch dataLen {
+		case 4:
+			k = uint(native.Uint32(p[i : i+dataLen]))
+			v = uint(native.Uint32(p[i+dataLen : i+dataLen*2]))
+		case 8:
+			k = uint(native.Uint64(p[i : i+dataLen]))
+			v = uint(native.Uint64(p[i+dataLen : i+dataLen*2]))
+		}
+		i += dataLen * 2
+		if k == what {
+			return v, nil
+		}
+	}
+	return 0, fmt.Errorf("cannot find %s in auxv", whatName)
+}
+
+// ClockTicks returns sysconf(SC_CLK_TCK).
+func ClockTicks() (int64, error) {
+	if clockTicks == nil {
+		ret, err := getFromAuxv(atClktck, "AT_CLKTCK")
+		if err != nil {
+			return -1, err
+		}
+		ticks := int64(ret)
+		clockTicks = &ticks
+	}
+	return *clockTicks, nil
+}