feat(tools/numap): add a tool to report NUMA topology of a host

The tool maps the various PCI devices to the NUMA node they are attached
to and print the result to STDOUT in JSON.

Only ethernet, NVMe and GPU devices are accounted for at the moment.

Change-Id: If32c805e61211f0ef4838a82eabc70d7fc1985fe
Reviewed-on: https://cl.fcuny.net/c/world/+/453
Tested-by: CI
Reviewed-by: Franck Cuny <franck@fcuny.net>

1 files changed, 148 insertions, 0 deletions

diff --git a/tools/numap/internal/hwids/hwids.go b/tools/numap/internal/hwids/hwids.go
new file mode 100644
index 0000000..6aa9d8a
--- /dev/null
+++ b/tools/numap/internal/hwids/hwids.go
@@ -0,0 +1,148 @@
+package hwids
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strings"
+)
+
+var pciPath = []string{
+	"/usr/share/hwdata/pci.ids",
+	"/usr/share/misc/pci.ids",
+}
+
+type PCIType int
+
+const (
+	PCIVendor PCIType = iota
+	PCIDevice
+	PCISubsystem
+)
+
+type PciDevices map[uint16][]PciDevice
+
+// PciDevice represents a PCI device
+type PciDevice struct {
+	Type                   PCIType
+	Vendor, Device         uint16
+	SubVendor, SubDevice   uint16
+	VendorName, DeviceName string
+	SubName                string
+}
+
+// Load load the hardware database for PCI devices and return a map of
+// vendor -> list of devices.
+func Load() (PciDevices, error) {
+	// if the environment variable HWDATAPATH is set, we add it to the
+	// list of paths we check for the hardware database.
+	extraPath := os.Getenv("HWDATA")
+	if extraPath != "" {
+		pciPath = append(pciPath, extraPath)
+	}
+
+	for _, f := range pciPath {
+		fh, err := os.Open(f)
+		if err != nil {
+			continue
+		}
+		defer fh.Close()
+		return parse(fh)
+	}
+	return PciDevices{}, fmt.Errorf("hwids: could not find a pci.ids file")
+}
+
+func parse(f *os.File) (PciDevices, error) {
+	devices := make(PciDevices)
+
+	s := bufio.NewScanner(f)
+
+	// this is to keep track of the current device. The format of the
+	// file is as follow:
+	// vendor  vendor_name
+	//       device  device_name                             <-- single tab
+	//               subvendor subdevice  subsystem_name     <-- two tabs
+	// the variable is to keep track of the current vendor / device
+	cur := PciDevice{}
+
+	for s.Scan() {
+		l := s.Text()
+		// skip empty lines or lines that are a comment
+		if len(l) == 0 || l[0] == '#' {
+			continue
+		}
+		// lines starting with a C are the classes definitions, and
+		// they are at the end of the file, which means we're done
+		// parsing the devices
+		if l[0] == 'C' {
+			break
+		}
+
+		parts := strings.SplitN(l, "  ", 2)
+		if len(parts) != 2 {
+			return devices, fmt.Errorf("hwids: malformed PCI ID line (missing ID separator): %s", l)
+		}
+
+		ids, name := parts[0], parts[1]
+		if len(ids) < 2 || len(name) == 0 {
+			return devices, fmt.Errorf("hwids: malformed PCI ID line (empty ID or name): %s", l)
+		}
+
+		cur.Type = PCIVendor
+
+		if ids[0] == '\t' {
+			if ids[1] == '\t' {
+				cur.Type = PCISubsystem
+			} else {
+				cur.Type = PCIDevice
+			}
+		}
+
+		var err error
+		switch cur.Type {
+		case PCIVendor:
+			_, err = fmt.Sscanf(ids, "%x", &cur.Vendor)
+			cur.VendorName = name
+		case PCIDevice:
+			_, err = fmt.Sscanf(ids, "%x", &cur.Device)
+			cur.DeviceName = name
+		case PCISubsystem:
+			_, err = fmt.Sscanf(ids, "%x %x", &cur.SubVendor, &cur.SubDevice)
+			cur.SubName = name
+		}
+
+		if err != nil {
+			return devices, fmt.Errorf("hwids: malformed PCI ID line: %s: %v", l, err)
+		}
+
+		// This is to reset the state when we are moving to a
+		// different vendor or device
+		switch cur.Type {
+		case PCIVendor:
+			cur.Device = 0
+			cur.DeviceName = ""
+			fallthrough
+		case PCIDevice:
+			cur.SubVendor = 0
+			cur.SubDevice = 0
+			cur.SubName = ""
+		}
+
+		_, ok := devices[cur.Vendor]
+		if ok {
+			_devices := devices[cur.Vendor]
+			_devices = append(_devices, cur)
+			devices[cur.Vendor] = _devices
+
+		} else {
+			_devices := []PciDevice{cur}
+			devices[cur.Vendor] = _devices
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return devices, fmt.Errorf("hwids: failed to read PCI ID line: %v", err)
+	}
+
+	return devices, nil
+}