introduce basic fact collection

client/vendor/github.com/zcalusic/sysinfo/memory.go

@@ -0,0 +1,121 @@
+// Copyright © 2016 Zlatko Čalušić
+//
+// Use of this source code is governed by an MIT-style license that can be found in the LICENSE file.
+
+package sysinfo
+
+import (
+	"bytes"
+	"encoding/binary"
+	"os"
+	"strconv"
+)
+
+// Memory information.
+type Memory struct {
+	Type  string `json:"type,omitempty"`
+	Speed uint   `json:"speed,omitempty"` // RAM data rate in MT/s
+	Size  uint   `json:"size,omitempty"`  // RAM size in MB
+}
+
+func word(data []byte, index int) uint16 {
+	return binary.LittleEndian.Uint16(data[index : index+2])
+}
+
+func dword(data []byte, index int) uint32 {
+	return binary.LittleEndian.Uint32(data[index : index+4])
+}
+
+func qword(data []byte, index int) uint64 {
+	return binary.LittleEndian.Uint64(data[index : index+8])
+}
+
+func (si *SysInfo) getMemoryInfo() {
+	dmi, err := os.ReadFile("/sys/firmware/dmi/tables/DMI")
+	if err != nil {
+		// Xen hypervisor
+		if targetKB := slurpFile("/sys/devices/system/xen_memory/xen_memory0/target_kb"); targetKB != "" {
+			si.Memory.Type = "DRAM"
+			size, _ := strconv.ParseUint(targetKB, 10, 64)
+			si.Memory.Size = uint(size) / 1024
+		}
+		return
+	}
+
+	si.Memory.Size = 0
+	var memSizeAlt uint
+loop:
+	for p := 0; p < len(dmi)-1; {
+		recType := dmi[p]
+		recLen := dmi[p+1]
+
+		switch recType {
+		case 4:
+			if si.CPU.Speed == 0 {
+				si.CPU.Speed = uint(word(dmi, p+0x16))
+			}
+		case 17:
+			size := uint(word(dmi, p+0x0c))
+			if size == 0 || size == 0xffff || size&0x8000 == 0x8000 {
+				break
+			}
+			if size == 0x7fff {
+				if recLen >= 0x20 {
+					size = uint(dword(dmi, p+0x1c))
+				} else {
+					break
+				}
+			}
+
+			si.Memory.Size += size
+
+			if si.Memory.Type == "" {
+				// SMBIOS Reference Specification Version 3.0.0, page 92
+				memTypes := [...]string{
+					"Other", "Unknown", "DRAM", "EDRAM", "VRAM", "SRAM", "RAM", "ROM", "FLASH",
+					"EEPROM", "FEPROM", "EPROM", "CDRAM", "3DRAM", "SDRAM", "SGRAM", "RDRAM",
+					"DDR", "DDR2", "DDR2 FB-DIMM", "Reserved", "Reserved", "Reserved", "DDR3",
+					"FBD2", "DDR4", "LPDDR", "LPDDR2", "LPDDR3", "LPDDR4",
+				}
+
+				if index := int(dmi[p+0x12]); index >= 1 && index <= len(memTypes) {
+					si.Memory.Type = memTypes[index-1]
+				}
+			}
+
+			if si.Memory.Speed == 0 && recLen >= 0x17 {
+				if speed := uint(word(dmi, p+0x15)); speed != 0 {
+					si.Memory.Speed = speed
+				}
+			}
+		case 19:
+			start := uint(dword(dmi, p+0x04))
+			end := uint(dword(dmi, p+0x08))
+			if start == 0xffffffff && end == 0xffffffff {
+				if recLen >= 0x1f {
+					start64 := qword(dmi, p+0x0f)
+					end64 := qword(dmi, p+0x17)
+					memSizeAlt += uint((end64 - start64 + 1) / 1048576)
+				}
+			} else {
+				memSizeAlt += (end - start + 1) / 1024
+			}
+		case 127:
+			break loop
+		}
+
+		for p += int(recLen); p < len(dmi)-1; {
+			if bytes.Equal(dmi[p:p+2], []byte{0, 0}) {
+				p += 2
+				break
+			}
+			p++
+		}
+	}
+
+	// Sometimes DMI type 17 has no information, so we fall back to DMI type 19, to at least get the RAM size.
+	if si.Memory.Size == 0 && memSizeAlt > 0 {
+		si.Memory.Type = "DRAM"
+		si.Memory.Size = memSizeAlt
+	}
+}