Swap out all usages of the syscall package (sourcegraph#513)

with the `golang.org/x/sys/unix` package.

`syscall` has been frozen since Go 1.3 and deprecated
(https://go.dev/doc/go1.4#major_library_changes).

Using the `golang.org/x/sys/unix` package will bring in bug fixes
and enhancements since `syscall` was frozen in 1.3,
and will pave the way for multi-platform builds
(which will affect only the single-program local install, most likely).

build/builder_unix.go

@@ -19,10 +19,11 @@ package build
 
 import (
 	"os"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 func init() {
-	umask = os.FileMode(syscall.Umask(0))
-	syscall.Umask(int(umask))
+	umask = os.FileMode(unix.Umask(0))
+	unix.Umask(int(umask))
 }

cmd/zoekt-sourcegraph-indexserver/main.go

@@ -27,10 +27,11 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"syscall"
 	"text/tabwriter"
 	"time"
 
+	"golang.org/x/sys/unix"
+
 	"github.com/keegancsmith/tmpfriend"
 	"github.com/peterbourgon/ff/v3/ffcli"
 	"github.com/prometheus/client_golang/prometheus"
@@ -247,7 +248,7 @@ func (s *Server) loggedRun(tr trace.Trace, cmd *exec.Cmd) (err error) {
 			} else {
 				// Send quit (C-\) first so we get a stack dump.
 				log.Printf("no output for %s, quitting %s", noOutputTimeout, cmd.Args)
-				if err := cmd.Process.Signal(syscall.SIGQUIT); err != nil {
+				if err := cmd.Process.Signal(unix.SIGQUIT); err != nil {
 					log.Println("quit failed:", err)
 				}
 
@@ -312,7 +313,7 @@ func (s *Server) Run() {
 		// testing we also listen for SIGUSR1 to trigger updates.
 		//
 		// "pkill -SIGUSR1 zoekt-sourcegra"
-		for range jitterTicker(s.Interval, syscall.SIGUSR1) {
+		for range jitterTicker(s.Interval, unix.SIGUSR1) {
 			if b, err := os.ReadFile(filepath.Join(s.IndexDir, pauseFileName)); err == nil {
 				log.Printf("indexserver manually paused via PAUSE file: %s", string(bytes.TrimSpace(b)))
 				continue
@@ -359,15 +360,15 @@ func (s *Server) Run() {
 	}()
 
 	go func() {
-		for range jitterTicker(s.VacuumInterval, syscall.SIGUSR1) {
+		for range jitterTicker(s.VacuumInterval, unix.SIGUSR1) {
 			if s.shardMerging {
 				s.vacuum()
 			}
 		}
 	}()
 
 	go func() {
-		for range jitterTicker(s.MergeInterval, syscall.SIGUSR1) {
+		for range jitterTicker(s.MergeInterval, unix.SIGUSR1) {
 			if s.shardMerging {
 				s.doMerge()
 			}

cmd/zoekt-sourcegraph-indexserver/meta.go

@@ -5,7 +5,8 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 
 	"github.com/sourcegraph/zoekt"
 	"github.com/sourcegraph/zoekt/build"
@@ -113,6 +114,6 @@ func jsonMarshalTmpFile(v interface{}, p string) (_ string, err error) {
 var umask os.FileMode
 
 func init() {
-	umask = os.FileMode(syscall.Umask(0))
-	syscall.Umask(int(umask))
+	umask = os.FileMode(unix.Umask(0))
+	unix.Umask(int(umask))
 }

cmd/zoekt-webserver/main.go

@@ -36,9 +36,10 @@ import (
 	"runtime"
 	"strconv"
 	"strings"
-	"syscall"
 	"time"
 
+	"golang.org/x/sys/unix"
+
 	"github.com/sourcegraph/mountinfo"
 
 	"github.com/sourcegraph/zoekt"
@@ -337,7 +338,7 @@ func addProxyHandler(mux *http.ServeMux, socket string) {
 func shutdownSignalChan(maxReads int) <-chan os.Signal {
 	c := make(chan os.Signal, maxReads)
 	signal.Notify(c, os.Interrupt)    // terminal C-c and goreman
-	signal.Notify(c, syscall.SIGTERM) // Kubernetes
+	signal.Notify(c, unix.SIGTERM) // Kubernetes
 	return c
 }
 
@@ -442,8 +443,8 @@ func mustRegisterDiskMonitor(path string) {
 		Help:        "Amount of free space disk space.",
 		ConstLabels: prometheus.Labels{"path": path},
 	}, func() float64 {
-		var stat syscall.Statfs_t
-		_ = syscall.Statfs(path, &stat)
+		var stat unix.Statfs_t
+		_ = unix.Statfs(path, &stat)
 		return float64(stat.Bavail * uint64(stat.Bsize))
 	}))
 
@@ -452,8 +453,8 @@ func mustRegisterDiskMonitor(path string) {
 		Help:        "Amount of total disk space.",
 		ConstLabels: prometheus.Labels{"path": path},
 	}, func() float64 {
-		var stat syscall.Statfs_t
-		_ = syscall.Statfs(path, &stat)
+		var stat unix.Statfs_t
+		_ = unix.Statfs(path, &stat)
 		return float64(stat.Blocks * uint64(stat.Bsize))
 	}))
 }

indexfile_unix.go

@@ -20,7 +20,8 @@ import (
 	"fmt"
 	"log"
 	"os"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 type mmapedIndexFile struct {
@@ -45,7 +46,7 @@ func (f *mmapedIndexFile) Size() (uint32, error) {
 }
 
 func (f *mmapedIndexFile) Close() {
-	if err := syscall.Munmap(f.data); err != nil {
+	if err := unix.Munmap(f.data); err != nil {
 		log.Printf("WARN failed to Munmap %s: %v", f.name, err)
 	}
 }
@@ -70,7 +71,7 @@ func NewIndexFile(f *os.File) (IndexFile, error) {
 	}
 
 	rounded := (r.size + 4095) &^ 4095
-	r.data, err = syscall.Mmap(int(f.Fd()), 0, int(rounded), syscall.PROT_READ, syscall.MAP_SHARED)
+	r.data, err = unix.Mmap(int(f.Fd()), 0, int(rounded), unix.PROT_READ, unix.MAP_SHARED)
 	if err != nil {
 		return nil, err
 	}

tombstones.go

@@ -6,7 +6,8 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
-	"syscall"
+
+	"golang.org/x/sys/unix"
 )
 
 // ShardMergingEnabled returns true if SRC_ENABLE_SHARD_MERGING is set to true.
@@ -104,6 +105,6 @@ func JsonMarshalRepoMetaTemp(shardPath string, repositoryMetadata interface{}) (
 var umask os.FileMode
 
 func init() {
-	umask = os.FileMode(syscall.Umask(0))
-	syscall.Umask(int(umask))
+	umask = os.FileMode(unix.Umask(0))
+	unix.Umask(int(umask))
 }