Implement ReadMemInfo on FreeBSD

Signed-off-by: Doug Rabson <[email protected]>

pkg/system/meminfo_freebsd.go

@@ -0,0 +1,75 @@
+//go:build freebsd && cgo
+// +build freebsd,cgo
+
+package system
+
+import (
+	"fmt"
+	"unsafe"
+
+	"golang.org/x/sys/unix"
+)
+
+// #include <unistd.h>
+// #include <sys/vmmeter.h>
+// #include <sys/sysctl.h>
+// #include <vm/vm_param.h>
+import "C"
+
+func getMemInfo() (int64, int64, error) {
+	data, err := unix.SysctlRaw("vm.vmtotal")
+	if err != nil {
+		return -1, -1, fmt.Errorf("Can't get kernel info: %v", err)
+	}
+	if len(data) != C.sizeof_struct_vmtotal {
+		return -1, -1, fmt.Errorf("unexpected vmtotal size %d", len(data))
+	}
+
+	total := (*C.struct_vmtotal)(unsafe.Pointer(&data[0]))
+
+	pagesize := int64(C.sysconf(C._SC_PAGESIZE))
+	npages := int64(C.sysconf(C._SC_PHYS_PAGES))
+	return pagesize * npages, pagesize * int64(total.t_free), nil
+}
+
+func getSwapInfo() (int64, int64, error) {
+	var (
+		total int64 = 0
+		used  int64 = 0
+	)
+	for i := 0; ; i++ {
+		data, err := unix.SysctlRaw("vm.swap_info", i)
+		if err != nil {
+			break
+		}
+		if len(data) != C.sizeof_struct_xswdev {
+			return -1, -1, fmt.Errorf("unexpected swap_info size %d", len(data))
+		}
+		xsw := (*C.struct_xswdev)(unsafe.Pointer(&data[0]))
+		total += int64(xsw.xsw_nblks)
+		used += int64(xsw.xsw_used)
+	}
+	pagesize := int64(C.sysconf(C._SC_PAGESIZE))
+	return pagesize * total, pagesize * used, nil
+}
+
+// ReadMemInfo retrieves memory statistics of the host system and returns a
+//  MemInfo type.
+func ReadMemInfo() (*MemInfo, error) {
+	MemTotal, MemFree, err := getMemInfo()
+	SwapTotal, SwapFree, err := getSwapInfo()
+
+	if MemTotal < 0 || MemFree < 0 || SwapTotal < 0 ||
+		SwapFree < 0 {
+		return nil, fmt.Errorf("error getting system memory info %v\n", err)
+	}
+
+	meminfo := &MemInfo{}
+	// Total memory is total physical memory less than memory locked by kernel
+	meminfo.MemTotal = MemTotal
+	meminfo.MemFree = MemFree
+	meminfo.SwapTotal = SwapTotal
+	meminfo.SwapFree = SwapFree
+
+	return meminfo, nil
+}

pkg/system/meminfo_unsupported.go

@@ -1,4 +1,5 @@
-// +build !linux,!windows,!solaris
+//go:build !linux && !windows && !solaris && !freebsd
+// +build !linux,!windows,!solaris,!freebsd
 
 package system