mirror of https://github.com/containers/podman.git
114 lines
2.4 KiB
Go
114 lines
2.4 KiB
Go
package ps
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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
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device string
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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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// ttyNrToDev returns the major and minor number of the tty device from
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// /proc/$pid/stat.tty_nr as described in man 5 proc.
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func ttyNrToDev(ttyNr uint64) (uint64, uint64) {
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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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return maj, min
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}
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// findTTY returns a tty with the corresponding major and minor device number
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// or nil if no matching tty is found.
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func findTTY(maj, min uint64) (*tty, error) {
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if len(ttyDevices) == 0 {
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var err error
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ttyDevices, err = getTTYs()
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if err != nil {
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return nil, err
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}
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}
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for _, t := range ttyDevices {
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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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// getTTYs parses /dev for tty and pts devices.
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func getTTYs() ([]*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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device: 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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