nvidia-container-toolkit/internal/info/proc/devices/devices.go
Evan Lezar 05632c0a40 Treat missing nvidia device majors as an error
Signed-off-by: Evan Lezar <elezar@nvidia.com>
2023-05-26 10:24:36 +02:00

142 lines
3.4 KiB
Go

/*
# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
*/
package devices
import (
"bufio"
"errors"
"fmt"
"io"
"os"
"strings"
)
// Device major numbers and device names for NVIDIA devices
const (
NVIDIAUVMMinor = 0
NVIDIAUVMToolsMinor = 1
NVIDIACTLMinor = 255
NVIDIAModesetMinor = 254
NVIDIAFrontend = Name("nvidia-frontend")
NVIDIAGPU = NVIDIAFrontend
NVIDIACaps = Name("nvidia-caps")
NVIDIAUVM = Name("nvidia-uvm")
procDevicesPath = "/proc/devices"
nvidiaDevicePrefix = "nvidia"
)
// Name represents the name of a device as specified under /proc/devices
type Name string
// Major represents a device major as specified under /proc/devices
type Major int
// Devices represents the set of devices under /proc/devices
//
//go:generate moq -stub -out devices_mock.go . Devices
type Devices interface {
Exists(Name) bool
Get(Name) (Major, bool)
}
type devices map[Name]Major
var _ Devices = devices(nil)
// Exists checks if a Device with a given name exists or not
func (d devices) Exists(name Name) bool {
_, exists := d[name]
return exists
}
// Get a Device from Devices
func (d devices) Get(name Name) (Major, bool) {
device, exists := d[name]
return device, exists
}
// GetNVIDIADevices returns the set of NVIDIA Devices on the machine
func GetNVIDIADevices() (Devices, error) {
return nvidiaDevices(procDevicesPath)
}
// nvidiaDevices returns the set of NVIDIA Devices from the specified devices file.
// This is useful for testing since we may be testing on a system where `/proc/devices` does
// contain a reference to NVIDIA devices.
func nvidiaDevices(devicesPath string) (Devices, error) {
devicesFile, err := os.Open(devicesPath)
if os.IsNotExist(err) {
return nil, nil
}
if err != nil {
return nil, fmt.Errorf("error opening devices file: %v", err)
}
defer devicesFile.Close()
return nvidiaDeviceFrom(devicesFile)
}
var errNoNvidiaDevices = errors.New("no NVIDIA devices found")
func nvidiaDeviceFrom(reader io.Reader) (devices, error) {
allDevices := devicesFrom(reader)
nvidiaDevices := make(devices)
var hasNvidiaDevices bool
for n, d := range allDevices {
if !strings.HasPrefix(string(n), nvidiaDevicePrefix) {
continue
}
nvidiaDevices[n] = d
hasNvidiaDevices = true
}
if !hasNvidiaDevices {
return nil, errNoNvidiaDevices
}
return nvidiaDevices, nil
}
func devicesFrom(reader io.Reader) devices {
allDevices := make(devices)
scanner := bufio.NewScanner(reader)
for scanner.Scan() {
device, major, err := processProcDeviceLine(scanner.Text())
if err != nil {
continue
}
allDevices[device] = major
}
return allDevices
}
func processProcDeviceLine(line string) (Name, Major, error) {
trimmed := strings.TrimSpace(line)
var name Name
var major Major
n, _ := fmt.Sscanf(trimmed, "%d %s", &major, &name)
if n == 2 {
return name, major, nil
}
return "", 0, fmt.Errorf("unparsable line: %v", line)
}