ref: f50d400cee33bddfad1fea8094bcfee5878eeb5f
parent: 3284ace53c5389c2aeadc9280dd32545cf0b3b0f
author: Manuel Mendez <mmendez534@gmail.com>
date: Tue Apr 25 05:04:25 CDT 2017
init: properly parse kernel serial console options
According to https://www.kernel.org/doc/Documentation/admin-guide/serial-console.rst
the serial port options is specified as:
"... BBBBPNF, where BBBB is the speed, P is parity (n/o/e), N is number of bits,
and F is flow control ('r' for RTS)." Parity and Number of bits are ignored
since getty does not have any options for them.
I tested the paramater substitution using the following script/snippet:
```sh
/ # cat /etc/alpine-release; cat kernel2getty.sh; sh kernel2getty.sh
3.5.2
consoles="ttyS0 ttyS0,115200 ttyS0,115200n8 ttyS0,115200n8r ttyS0,115200r"
for console in $consoles; do
line=-L
term=vt100
tty=${console%,*}
speed=${console#*,}
flow=${speed##*[^r]}
speed=${speed%%[^0-9]*}
echo "console=$console"
echo " speed=$speed"
echo " flow=$flow"
echo " getty=getty ${flow:+-h }$line ${speed:-15200} $tty $term"
echo "----------"
done
console=ttyS0
speed=
flow=
getty=getty -L 15200 ttyS0 vt100
----------
console=ttyS0,115200
speed=115200
flow=
getty=getty -L 115200 ttyS0 vt100
----------
console=ttyS0,115200n8
speed=115200
flow=
getty=getty -L 115200 ttyS0 vt100
----------
console=ttyS0,115200n8r
speed=115200
flow=r
getty=getty -h -L 115200 ttyS0 vt100
----------
console=ttyS0,115200r
speed=115200
flow=r
getty=getty -h -L 115200 ttyS0 vt100
----------
```
closes #7037
--- a/initramfs-init.in
+++ b/initramfs-init.in
@@ -113,9 +113,11 @@
local term=
case "$tty" in
ttyS*|ttyMFD*|ttyUSB*|ttyAMA*)
- [ "$speed" = "$1" ] && speed=115200
term=vt100
line=-L
+ flow=${speed##*[^r]}+ speed=${speed%%[^0-9]*}+ speed=${speed:-115200};;
*)
[ "$speed" = "$1" ] && speed=38400