mirror of
https://github.com/containers/podman.git
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508ab7f565
The psgo library now be used concurrently by multiple goroutines without interferring with another. Signed-off-by: Valentin Rothberg <rothberg@redhat.com>
125 lines
2.7 KiB
Go
125 lines
2.7 KiB
Go
// Copyright 2018 psgo authors
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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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package dev
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import (
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"os"
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"strings"
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"syscall"
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)
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// TTY represents a tty including its minor and major device number and the
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// path to the tty.
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type TTY struct {
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// Minor device number.
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Minor uint64
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// Major device number.
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Major uint64
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// Path to the tty device.
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Path string
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}
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// FindTTY return the corresponding TTY to the ttyNr or nil of non could be
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// found.
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func FindTTY(ttyNr uint64, devices *[]TTY) (*TTY, error) {
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// (man 5 proc) The minor device number is contained in the combination
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// of bits 31 to 20 and 7 to 0; the major device number is in bits 15
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// to 8.
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maj := (ttyNr >> 8) & 0xFF
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min := (ttyNr & 0xFF) | ((ttyNr >> 20) & 0xFFF)
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if devices == nil {
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devs, err := TTYs()
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if err != nil {
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return nil, err
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}
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devices = devs
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}
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for _, t := range *devices {
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if t.Minor == min && t.Major == maj {
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return &t, nil
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}
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}
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return nil, nil
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}
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// majDevNum returns the major device number of rdev (see stat_t.Rdev).
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func majDevNum(rdev uint64) uint64 {
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return (rdev >> 8) & 0xfff
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}
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// minDevNum returns the minor device number of rdev (see stat_t.Rdev).
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func minDevNum(rdev uint64) uint64 {
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return (rdev & 0xff) | ((rdev >> 12) & 0xfff00)
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}
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// TTYs parses /dev for tty and pts devices.
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func TTYs() (*[]TTY, error) {
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devDir, err := os.Open("/dev/")
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if err != nil {
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return nil, err
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}
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defer devDir.Close()
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devices := []string{}
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devTTYs, err := devDir.Readdirnames(0)
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if err != nil {
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return nil, err
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}
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for _, d := range devTTYs {
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if !strings.HasPrefix(d, "tty") {
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continue
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}
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devices = append(devices, "/dev/"+d)
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}
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devPTSDir, err := os.Open("/dev/pts/")
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if err != nil {
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return nil, err
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}
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defer devPTSDir.Close()
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devPTSs, err := devPTSDir.Readdirnames(0)
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if err != nil {
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return nil, err
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}
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for _, d := range devPTSs {
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devices = append(devices, "/dev/pts/"+d)
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}
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ttys := []TTY{}
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for _, dev := range devices {
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fi, err := os.Stat(dev)
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if err != nil {
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if os.IsNotExist(err) {
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// catch race conditions
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continue
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}
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return nil, err
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}
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s := fi.Sys().(*syscall.Stat_t)
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t := TTY{
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Minor: minDevNum(s.Rdev),
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Major: majDevNum(s.Rdev),
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Path: dev,
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}
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ttys = append(ttys, t)
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}
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return &ttys, nil
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}
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