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package sshd
import "encoding/binary"
// Helpers below are borrowed from go.crypto circa 2011:
// parsePtyRequest parses the payload of the pty-req message and extracts the
// dimensions of the terminal. See RFC 4254, section 6.2.
func parsePtyRequest(s []byte) (term string, width, height int, ok bool) {
term, s, ok = parseString(s)
if !ok {
return
}
width32, s, ok := parseUint32(s)
if !ok {
return
}
height32, _, ok := parseUint32(s)
width = int(width32)
height = int(height32)
if width < 1 {
ok = false
}
if height < 1 {
ok = false
}
return
}
func parseWinchRequest(s []byte) (width, height int, ok bool) {
width32, _, ok := parseUint32(s)
if !ok {
return
}
height32, _, ok := parseUint32(s)
if !ok {
return
}
width = int(width32)
height = int(height32)
if width < 1 {
ok = false
}
if height < 1 {
ok = false
}
return
}
func parseString(in []byte) (out string, rest []byte, ok bool) {
if len(in) < 4 {
return
}
length := binary.BigEndian.Uint32(in)
if uint32(len(in)) < 4+length {
return
}
out = string(in[4 : 4+length])
rest = in[4+length:]
ok = true
return
}
func parseUint32(in []byte) (uint32, []byte, bool) {
if len(in) < 4 {
return 0, nil, false
}
return binary.BigEndian.Uint32(in), in[4:], true
}
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