[android][host] fix Info() failure due to forbidden /proc/stat and /proc/uptime (#1361)

* [android][host] fallback to sysinfo() syscall for uptime

with Android O, /proc/{stat,uptime} both return permission denied

internal/common/common_linux.go

@@ -12,6 +12,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
+	"syscall"
 	"time"
 )
 
@@ -68,6 +69,17 @@ func BootTimeWithContext(ctx context.Context) (uint64, error) {
 
 	filename := HostProc(statFile)
 	lines, err := ReadLines(filename)
+	if os.IsPermission(err) {
+		var info syscall.Sysinfo_t
+		err := syscall.Sysinfo(&info)
+		if err != nil {
+			return 0, err
+		}
+
+		currentTime := time.Now().UnixNano() / int64(time.Second)
+		t := currentTime - int64(info.Uptime)
+		return uint64(t), nil
+	}
 	if err != nil {
 		return 0, err
 	}