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https://github.com/NVIDIA/nvidia-container-toolkit
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95394e0fc8
This change adds basic functionality to process the /proc/devices file to extract device majors. Signed-off-by: Evan Lezar <elezar@nvidia.com>
126 lines
2.9 KiB
Go
126 lines
2.9 KiB
Go
/*
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# Copyright (c) 2021, NVIDIA CORPORATION. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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*/
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package devices
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"strings"
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)
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// Device major numbers and device names for NVIDIA devices
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const (
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NVIDIAUVMMinor = 0
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NVIDIAUVMToolsMinor = 1
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NVIDIACTLMinor = 255
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NVIDIAModesetMinor = 254
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NVIDIAFrontend = Name("nvidia-frontend")
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NVIDIAGPU = NVIDIAFrontend
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NVIDIACaps = Name("nvidia-caps")
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NVIDIAUVM = Name("nvidia-uvm")
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procDevicesPath = "/proc/devices"
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nvidiaDevicePrefix = "nvidia"
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)
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// Name represents the name of a device as specified under /proc/devices
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type Name string
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// Major represents a device major as specified under /proc/devices
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type Major int
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// Devices represents the set of devices under /proc/devices
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//
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//go:generate moq -stub -out devices_mock.go . Devices
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type Devices interface {
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Exists(Name) bool
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Get(Name) (Major, bool)
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}
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type devices map[Name]Major
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var _ Devices = devices(nil)
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// Exists checks if a Device with a given name exists or not
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func (d devices) Exists(name Name) bool {
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_, exists := d[name]
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return exists
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}
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// Get a Device from Devices
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func (d devices) Get(name Name) (Major, bool) {
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device, exists := d[name]
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return device, exists
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}
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// GetNVIDIADevices returns the set of NVIDIA Devices on the machine
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func GetNVIDIADevices() (Devices, error) {
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devicesFile, err := os.Open(procDevicesPath)
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if os.IsNotExist(err) {
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return nil, nil
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}
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if err != nil {
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return nil, fmt.Errorf("error opening devices file: %v", err)
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}
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defer devicesFile.Close()
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return nvidiaDeviceFrom(devicesFile), nil
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}
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func nvidiaDeviceFrom(reader io.Reader) devices {
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allDevices := devicesFrom(reader)
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nvidiaDevices := make(devices)
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for n, d := range allDevices {
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if !strings.HasPrefix(string(n), nvidiaDevicePrefix) {
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continue
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}
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nvidiaDevices[n] = d
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}
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return nvidiaDevices
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}
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func devicesFrom(reader io.Reader) devices {
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allDevices := make(devices)
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scanner := bufio.NewScanner(reader)
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for scanner.Scan() {
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device, major, err := processProcDeviceLine(scanner.Text())
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if err != nil {
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continue
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}
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allDevices[device] = major
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}
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return allDevices
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}
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func processProcDeviceLine(line string) (Name, Major, error) {
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trimmed := strings.TrimSpace(line)
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var name Name
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var major Major
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n, _ := fmt.Sscanf(trimmed, "%d %s", &major, &name)
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if n == 2 {
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return name, major, nil
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}
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return "", 0, fmt.Errorf("unparsable line: %v", line)
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}
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