Fix build issues on BSDs in pkg/cpu (#7116)

Also add a cross compile script to test always cross
compilation for some well known platforms and architectures
, we support out of box compilation of these platforms even
if we don't make an official release build.

This script is to avoid regressions in this area when we
add platform dependent code.

.travis.yml

@@ -23,6 +23,8 @@ matrix:
         - diff -au <(gofmt -s -d cmd) <(printf "")
         - diff -au <(gofmt -s -d pkg) <(printf "")
         - for d in $(go list ./... | grep -v browser); do CGO_ENABLED=1 go test -v -race --timeout 15m "$d"; done
+        - make verifiers
+        - make crosscompile
         - make verify
         - make coverage
         - cd browser && yarn && yarn test && cd ..

Makefile

@@ -19,6 +19,9 @@ getdeps:
 	@echo "Installing misspell" && go get -u github.com/client9/misspell/cmd/misspell
 	@echo "Installing ineffassign" && go get -u github.com/gordonklaus/ineffassign
 
+crosscompile:
+	@(env bash $(PWD)/buildscripts/cross-compile.sh)
+
 verifiers: getdeps vet fmt lint cyclo deadcode spelling
 
 vet:

buildscripts/cross-compile.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+# Enable tracing if set.
+[ -n "$BASH_XTRACEFD" ] && set -ex
+
+function _init() {
+    ## All binaries are static make sure to disable CGO.
+    export CGO_ENABLED=0
+
+    ## List of architectures and OS to test coss compilation.
+    SUPPORTED_OSARCH="linux/ppc64le linux/arm64 linux/s390x darwin/amd64 freebsd/amd64"
+}
+
+function _build_and_sign() {
+    local osarch=$1
+    IFS=/ read -r -a arr <<<"$osarch"
+    os="${arr[0]}"
+    arch="${arr[1]}"
+    package=$(go list -f '{{.ImportPath}}')
+    printf -- "--> %15s:%s\n" "${osarch}" "${package}"
+
+    # Go build to build the binary.
+    export GOOS=$os
+    export GOARCH=$arch
+    go build -tags kqueue -o /dev/null
+}
+
+function main() {
+    echo "Testing builds for OS/Arch: ${SUPPORTED_OSARCH}"
+    for each_osarch in ${SUPPORTED_OSARCH}; do
+        _build_and_sign "${each_osarch}"
+    done
+}
+
+_init && main "$@"

cmd/bitrot.go

@@ -39,7 +39,7 @@ const (
 	SHA256 BitrotAlgorithm = 1 + iota
 	// HighwayHash256 represents the HighwayHash-256 hash function
 	HighwayHash256
-	// HighwayHash256 represents the Streaming HighwayHash-256 hash function
+	// HighwayHash256S represents the Streaming HighwayHash-256 hash function
 	HighwayHash256S
 	// BLAKE2b512 represents the BLAKE2b-512 hash function
 	BLAKE2b512

cmd/erasure.go

@@ -93,10 +93,12 @@ func (e *Erasure) DecodeDataAndParityBlocks(ctx context.Context, data [][]byte)
 	return nil
 }
 
+// ShardSize - returns actual shared size from erasure blockSize.
 func (e *Erasure) ShardSize() int64 {
 	return ceilFrac(e.blockSize, int64(e.dataBlocks))
 }
 
+// ShardFileSize - returns final erasure size from original size.
 func (e *Erasure) ShardFileSize(totalLength int64) int64 {
 	if totalLength == 0 {
 		return 0
@@ -107,6 +109,7 @@ func (e *Erasure) ShardFileSize(totalLength int64) int64 {
 	return numShards*e.ShardSize() + lastShardSize
 }
 
+// ShardFileTillOffset - returns the effectiv eoffset where erasure reading begins.
 func (e *Erasure) ShardFileTillOffset(startOffset, length, totalLength int64) int64 {
 	shardSize := e.ShardSize()
 	shardFileSize := e.ShardFileSize(totalLength)

cmd/posix.go

@@ -1015,7 +1015,7 @@ func (s *posix) ReadFileStream(volume, path string, offset, length int64) (io.Re
 	if _, err = file.Seek(offset, io.SeekStart); err != nil {
 		return nil, err
 	}
-	return &posixLimitedReader{io.LimitedReader{file, length}}, nil
+	return &posixLimitedReader{io.LimitedReader{R: file, N: length}}, nil
 }
 
 // CreateFile - creates the file.

pkg/cpu/counter_linux.go

@@ -20,12 +20,8 @@ import (
 	"syscall"
 	"time"
 	"unsafe"
-)
 
-const (
-	// ProcessClock corresponds to the High-resolution per-process
-	// timer from the CPU represented in stdlib as CLOCK_PROCESS_CPUTIME_ID
-	processClock = 2
+	"golang.org/x/sys/unix"
 )
 
 func newCounter() (counter, error) {
@@ -34,7 +30,8 @@ func newCounter() (counter, error) {
 
 func (c counter) now() time.Time {
 	var ts syscall.Timespec
-	syscall.Syscall(syscall.SYS_CLOCK_GETTIME, processClock, uintptr(unsafe.Pointer(&ts)), 0)
+	// Retrieve Per-process CPU-time clock
+	syscall.Syscall(syscall.SYS_CLOCK_GETTIME, unix.CLOCK_PROCESS_CPUTIME_ID, uintptr(unsafe.Pointer(&ts)), 0)
 	sec, nsec := ts.Unix()
 	return time.Unix(sec, nsec)
 }

pkg/cpu/counter_darwin.go → pkg/cpu/counter_other.go

@@ -1,3 +1,5 @@
+// +build darwin freebsd openbsd netbsd dragonfly windows
+
 /*
  * Minio Cloud Storage, (C) 2019 Minio, Inc.
  *
@@ -17,12 +19,13 @@
 package cpu
 
 import (
-	"errors"
+	"fmt"
+	"runtime"
 	"time"
 )
 
 func newCounter() (counter, error) {
-	return counter{}, errors.New("cpu metrics not implemented for darwin platform")
+	return counter{}, fmt.Errorf("cpu metrics not implemented for %s platform", runtime.GOOS)
 }
 
 func (c counter) now() time.Time {