Introduction

In my application I have a embedded Linux board, where I have some application accessing to a UART. The remote device will send command to the UART. The remote device is not yet ready. Before that, we could use Pseudo tty to do loopback testing.

socat

buildroot is used for this embedded system, socat is not default installed. We could always use following command in buildroot/out/xxxxx/ directory to build the socat.

make socat-rebuild

push socat to target

In the embedded system: (following is the console in adb)

# socat -d -d pty,raw,echo=0 pty,raw,echo=0
1970/01/01 02:33:08 socat[2055] N PTY is /dev/pts/1
1970/01/01 02:33:08 socat[2055] N PTY is /dev/pts/2
1970/01/01 02:33:08 socat[2055] N starting data transfer loop with FDs [5,5] and [7,7]

Above command creates a loop tunnel between two pts (pseudo tty). So we could change the application code to talk to /dev/pts/1, and then we could write to /dev/pts/2 to emulate a remote writing, and vice verse.

Following command emulate the application to accept a command:

# cat < /dev/pts/2
hello

Following command emulates the remote to send the command:

# echo "hello" > /dev/pts/1