Kim Woelders
0f879c8b61
In certain cases we may get zero size reads (e.g. if the server sends an rfc2217 notification without any other data). In this situation we must not propagate the zero size read to user space as it may be interpreted as end of input. I haven't found a way to tell fuse that it should just ignore this read but passing EINTR seems to work.
1 Build environment
The gcc compiler is used by default (see Makefile).
libfuse-dev - Filesystem in Userspace (development) must be installed
at the build system.
glibc must support pthreads.
2 Target
The linux kernel at the target system must support FUSE (FUSE_FS=y) and
libpthread and libfuse must be installed in the root filesystem.
3 Build
The default target in the Makefile builds the Network Virtual Terminal.
Output name is: ttynvt.
4 Run
The application (ttynvt) installs a virtual serial device in the /dev
directory (by default: /dev/ttyNVT0).
The major/minor number of the device, the address (name/IP) and the port
number of the serial server must be specified when the application
is started (command-line options).
E.g.
./ttynvt -M 199 -m 6 -n ttyNVT0 -p 5020 -s 169.254.1.1
To get a list of all command-line options:
./ttynvt --help
5. Test
The serial server: ser2net (http://ser2net.sourceforge.net/) might be used
to test the virtual serial server on the target.
Install the server (ser2net) and add folling line to the configuration
file (/etc/ser2net.conf):
5020:telnet:0:/dev/ttyS0:115200 remctl NONE 1STOPBIT 8DATABITS RTSCTS HANGUP_WHEN_DONE
At the server, plug-in a loopback connector in the serial port (ttyS0).
At the target, open the virtual serial port, with a termial program,
e.g minicom:
minicom -D /dev/ttyNVT0
6 Diagnostic
Add the command-line option '-l' to enable logging of diagnostic information.
Wireshark is also very useful when debugging the interface between the client
and the server.
Ref: RFC-854 - Telnet Protocol Specification
RFC-2217 - Telnet Com Port Control Option