#!/bin/sh

# Listen in on serial port connections.
# (Note that max packet size is hardcoded to be 512)
# Written by jan2642

if [ "$#" -ne 1 ]; then
    echo "Usage: $0 <path to serial port>"
fi

/usr/sbin/dtrace -n '
inline string PATHNAME	 = "'$1'";

#pragma D option quiet
#pragma D option switchrate=10hz
/* #pragma D option bufpolicy=ring */

dtrace:::BEGIN
{
}

syscall::open:entry, syscall::open_nocancel:entry, syscall::open_extended:entry
{
    self->path = arg0;
    self->file_open_in_progress = 1;
}

syscall::open:return, syscall::open_nocancel:return, syscall::open_extended:return
/self->file_open_in_progress && (PATHNAME == copyinstr(self->path))/
{
    the_pid = pid;
    the_fd = arg1;
    
    self->path = 0;
    self->file_open_in_progress = 0;
}

syscall::*read:entry
/pid == the_pid && arg0 == the_fd/
{ 
    self->read_in_progress = 1;
    self->read_ptr = arg1;
}

syscall::*read:return
/self->read_in_progress/
{
    if (arg0 > 0) {
        printf("==+ %s IN %d : ", execname, (int)arg0);
        tracemem(copyin(self->read_ptr, arg0), 512);
        printf("==-\n");
    }
    
    self->read_in_progress = 0;
}

syscall::*write:entry
/pid == the_pid && arg0 == the_fd/
{ 
    if (arg2 > 0) {
        printf("==+ %s OUT %d : ", execname, (int)arg2);
        tracemem(copyin(arg1, arg2), 512);
        printf("==-\n");
    }
}

' 2> /dev/null | python -c '
import sys

def parse_block(buf):
    lines = buf.split("\n");
    meta = lines[0].split(" ")

    proc = meta[1]
    direction = meta[2]
    size = int(meta[3])

    print("%s %-3s %5d :" % (proc, direction, size)),

    if size > 512:
        size = 512 

    for i in xrange(0, (size / 16) + 1):
        data = lines[2 + i].strip().split(" ")
        remain = 16
        if i == size / 16:
            remain = size % 16
        for j in xrange(0, remain):
            print("%s" % data[j + 1]),
    print("")

for line in sys.stdin:
    if line.startswith("==+"):
        buf = "";
    if line.startswith("==-"):
        parse_block(buf)
    buf += line
'

# vim: expandtab:ts=4:sw=4