vendor latest containers/psgo

Signed-off-by: Valentin Rothberg <vrothberg@suse.com>

Closes: #1162
Approved by: rhatdan

vendor/github.com/containers/psgo/internal/dev/tty.go

@@ -0,0 +1,113 @@
+package dev
+
+import (
+	"os"
+	"strings"
+	"syscall"
+)
+
+// TTY represents a tty including its minor and major device number and the
+// path to the tty.
+type TTY struct {
+	// Minor device number.
+	Minor uint64
+	// Major device number.
+	Major uint64
+	// Path to the tty device.
+	Path string
+}
+
+// cache TTYs to avoid redundant lookups
+var devices *[]TTY
+
+// FindTTY return the corresponding TTY to the ttyNr or nil of non could be
+// found.
+func FindTTY(ttyNr uint64) (*TTY, error) {
+	// (man 5 proc) The minor device number is contained in the combination
+	// of bits 31 to 20 and 7 to 0; the major device number is in bits 15
+	// to 8.
+	maj := (ttyNr >> 8) & 0xFF
+	min := (ttyNr & 0xFF) | ((ttyNr >> 20) & 0xFFF)
+
+	if devices == nil {
+		devs, err := getTTYs()
+		if err != nil {
+			return nil, err
+		}
+		devices = devs
+	}
+
+	for _, t := range *devices {
+		if t.Minor == min && t.Major == maj {
+			return &t, nil
+		}
+	}
+
+	return nil, nil
+}
+
+// majDevNum returns the major device number of rdev (see stat_t.Rdev).
+func majDevNum(rdev uint64) uint64 {
+	return (rdev >> 8) & 0xfff
+}
+
+// minDevNum returns the minor device number of rdev (see stat_t.Rdev).
+func minDevNum(rdev uint64) uint64 {
+	return (rdev & 0xff) | ((rdev >> 12) & 0xfff00)
+}
+
+// getTTYs parses /dev for tty and pts devices.
+func getTTYs() (*[]TTY, error) {
+	devDir, err := os.Open("/dev/")
+	if err != nil {
+		return nil, err
+	}
+	defer devDir.Close()
+
+	devices := []string{}
+	devTTYs, err := devDir.Readdirnames(0)
+	if err != nil {
+		return nil, err
+	}
+	for _, d := range devTTYs {
+		if !strings.HasPrefix(d, "tty") {
+			continue
+		}
+		devices = append(devices, "/dev/"+d)
+	}
+
+	devPTSDir, err := os.Open("/dev/pts/")
+	if err != nil {
+		return nil, err
+	}
+	defer devPTSDir.Close()
+
+	devPTSs, err := devPTSDir.Readdirnames(0)
+	if err != nil {
+		return nil, err
+	}
+	for _, d := range devPTSs {
+		devices = append(devices, "/dev/pts/"+d)
+	}
+
+	ttys := []TTY{}
+	for _, dev := range devices {
+		fi, err := os.Stat(dev)
+		if err != nil {
+			if os.IsNotExist(err) {
+				// catch race conditions
+				continue
+			}
+			return nil, err
+		}
+		s := fi.Sys().(*syscall.Stat_t)
+		t := TTY{
+			Minor: minDevNum(s.Rdev),
+			Major: majDevNum(s.Rdev),
+			Path:  dev,
+		}
+		ttys = append(ttys, t)
+	}
+
+	return &ttys, nil
+}