Why upgrade? I'm not a lawyer, but here's my take on the differences
to version 2:
* Software patents: better protection against abuse of patents to
prevent users from exercising the rights under the GPL. I doubt
we'll get hit with a patent suit, but it's a good move just on
general principles.
* License compatibility: compatible with more free licenses, i.e. can
"steal" more free software for use in Empire. I don't expect to steal
much, but it's nice to have the option.
* Definition of "source code": modernization of some details for today's
networked world, to make it easier to distribute the software. Not
really relevant to us now, as we normally distribute full source code.
* Tivoization: this is about putting GPL-licensed software in hardware,
then make the hardware refuse to run modified software. "Neat" trick
to effectively deny its users their rights under the GPL. Abuse was
"pioneered" by TiVo (popular digital video recorders). GPLv3 forbids
it. Unlikely to become a problem for us.
* Internationalization: more careful wording, to harden the license
outside the US. The lawyers tell us it better be done that way.
* License violations: friendlier way to deal with license violations.
This has come out of past experience enforcing the GPL.
* Additional permissions: Probably not relevant to us.
Also include myself in the list of principal authors.
The server aborts the current command when it receives a special line
of input for a prompt. To make the client send it, you type the INTR
character (normally ^C). This sends the client the SIGINT signal.
Unfortunately, it never quite worked.
Because we use a special line of input to signal interrupt, the client
can do that only after a complete line of input.
What if SIGINT arrives in the middle of a line? We split the line in
two then and there, by inserting a newline. Nasty, but it's simple,
and happens rarely.
However, we inserted the newline always, even after a complete line.
In that case, we inserted an empty line of input before the interrupt.
If you hit INTR at a server prompt, the server received an empty line
of input for that prompt, and the interrupt only for the *next*
prompt. Which may well be too late to abort the command you wanted to
abort.
Fix by inserting the newline only when needed.
Move client's w32_connect() to w32sockets.c.
Replace w32_recv() and w32_send() by read() and write().
Replace w32_close() by w32_close_function.
Replace call of WSAStartup() in w32_sysdep_init() by
w32_socket_init().
Remove the identical copies of fd_is_socket(),
w32_set_winsock_errno(), w32_socket().
Unlike POSIX sockets, Windows sockets are not file descriptors, but
"OS handles", with a completely separate set of functions.
However, Windows can create a file descriptor for a socket, and return
a file descriptor's underlying handle. Use that instead of our gross
hacks to keep up the illusion that sockets are file descriptors.
Slightly dirty: we put file descriptors into fd_set. Works because
both boil down to int. Change w32_select(), w32_socket(),
w32_connect(), w32_recv(), w32_writev_socket(), w32_send() to take and
return only file descriptors, and map to sockets internally. Replace
w32_close_socket() by w32_close(), and drop the close() macro hackery
that made tcp_connect(), host_connect() use w32_close_socket(). New
fd_is_socket().
Windows provides select()-like functions only for handles. Because of
that, the client used a handle for reading script files, and stored it
in file descriptor input_fd. Drop this dirty hack, use a file
descriptor instead. Works because we can get its underlying handle.
Remove the dirty macro hackery that made play(), ring_from_file() and
doexecute() unwittingly work with a handle. Remove w32_openhandle()
and w32_close_handle(). Replace w32_readv_handle() by w32_readv_fd().
Update w32_select().
Remove w32_openfd(), it's not really needed.
The old code stuffed WSA error codes into errno, which doesn't work.
Use new w32_set_winsock_errno() to convert & stuff.
Fix signed vs. unsigned warnings in Windows client.
Move the struct sigaction replacement next to the sigaction()
replacement.
Rename sysdep_init() to w32_sysdep_init() for consistency.
When select() gets interrupted by SIGINT while a handler is active
without SA_RESTART, it returns immediately with EINTR. w32_select()
did that only while it waited for standard input to become ready for
reading. This isn't the case when:
* The client has already received EOF on standard input. But then the
action is SIG_DFL, so there was no problem.
* Reading standard input is suspended until the server drains the
input buffer. Then reaction to Ctrl-C got delayed until the socket
got ready, and w32_select() returned normally. Harmless, because
the reaction merely appends to the input buffer.
Change w32_select() to match select()'s behavior anyway.
We use the C run-time, so we better use its _beginthread(), too.
CreateThread() can lead to deadlocks, at least with some versions of
the C run-time. Broken in commit f082ef9f, v4.3.11.
stdin_read_thread() zeroed bounce_status on failure, effectifely
treating it like EOF. Fix by setting to -1.
It treated main thread termination like failure, and set bounce_error
to a bogus value. Can't happen, because the program terminates when
the main thread terminates, and the only user of bounce_error is the
main thread anyway. Regardless, handle the case by terminating,
because that's more obviously correct.
Broken in commit f082ef9f, v4.3.11.
Should be more portable to modern systems and could be less portable
to obsolete systems than the traditional sys/time.h sys/types.h
unistd.h incantation.
Player input may overtake batch file contents (well-known protocol
flaw, see doc/clients-howto for details). This includes EOF. When
that happens, the client closes standard input, sends an EOF cookie,
and continues reading output until the server closes the connection.
When it gets C_EXECUTE, it redirects input to the batch file. But it
then failed to read the batch file. The server waited forever for the
execute's EOF cookie, the client waited forever for the server closing
the connection.
Fix by stopping only reading from standard input. Broken in 8b7d0b91,
v4.3.11.
Note that the EOF cookie still overtakes the batch file contents,
which makes the server interpret the input between the execute command
and the EOF as batch file, and the batch file contents as ordinary
input.
Remove the names for the bounce_empty, bounce_full and ctrl_c_event
events. The named events were being shared between all clients running
on a WIN32 machine which created the affect of disconnecting a client
when an input event occurred in another client. Broken in commit
f082ef9f (v4.3.11).
w32_writev_socket, w32_close_socket, getpass, w32_openfd,
w32_openhandle, w32_readv_handle, w32_close_handle,
sysdep_init, sysdep_stdin_init, w32_select, w32_signal_handler,
sigaction, stdin_read_thread, w32_ring_from_file_to_bounce_buf)
[_WIN32]: New w32 equivalent functions for POSIX functions.
(recvline, sendcmd, tcp_connect, hostconnect, getpass,
main, intr, play, ring_to_file, ring_from_file, doexecute,
doredir) [_WIN32]: Use new WIN32 equivalent functions.
(main) [_WIN32]: Add sysdep_init() to support system dependent
initialization for equivalence functions.
(play) [_WIN32]: Add sysdef_stdin_init() to support system
dependent initialization for reading stdin.
(recv_input, play) [_WIN32]: Replace the calls to ring_to_file()
and select() with WIN32 specific enhanced versions.
Makefile.in: update dependencies with new files.
Make.mk: Add using of getopt.c and getopt.h
from src/lib/w32 directory. Add getopt.c and getopt.h
to tar for client.
impossible to implement correctly, and nested execute practically
useless (#116377). Catch and refuse those:
(executing): New.
(doexecute, prompt): Set and clear it.
(redir_authorized): Reject if set.
(doexecute, play): Don't signal doexecute() failure through input_fd,
because that screws up up when we're executing already. Increment
send_eof in doexecute() instead.
(send_eof): External linkage.
of clearing it. Fixes a race condition: when we got EOF on input_fd
and a failed doexecute() in the same iteration of the loop, only one
EOF cookie was sent, leaving the client hung.
fixes error handling when a script can be opened but not read: it
switches back to standard input. And it handles errors on standard
input more gracefully: orderly shutdown, buffered output is still
written out.
(EOF_COOKIE, INTR_COOKIE, input_fd, send_intr, recv_output)
(recv_input, intr, play): New playing phase code. No native Windows
support yet. Sends just one EOF cookie on EOF on standard input
instead of up to three. Old servers (before recvclient.c rev. 1.16)
fail to terminate the session when they receive an EOF cookie at an
argument prompt. The session then hangs; use SIGINT to get out. No
longer blocks on sending input, which could deadlock the session.
Closes#827090. Fixes error handling for select(). Fixes race
condition that could cause server output to be discarded on EOF on
standard input.
(main): Replace old playing phase code by a call to play().
(intr, sock, interrupt, handleintr): Replaced by play(), remove.
[_WIN32] (hStdIn): Ditto.
(auxfp): New.
(servercmd, prompt, doexecute): Remove parameter auxfi, use auxfp.
(eight_bit_clean): Move to servcmd.c.
(servercmd): Work on a single non-C_DATA line instead of getting lines
from an ioqueue.
(servercmd, output, screen, outch): Deal with all ids in servercmd()
rather than some there and some in output(). Don't treat C_NOECHO,
C_ABORT, C_CMDERR, C_BADCMD specially. Fix C_FLASH and C_EXIT to
ignore redirections; they used to ignore them only for some parts.
Replace output() by outch(), fold screen into outch().
(servercmd): Truncate long prompts and telegram infos to prevent
buffer overflow.
(prompt): Use new parameters code, prompt, teles instead of global
variables mode, the_prompt, num_teles.
(num_teles, the_prompt, mode, nbtu, nmin): Remove.
(prompt): Don't write an empty line before argument prompts to auxfp.
(servercmd): Don't strip newline from redirections and execute,
doredir(), dopipe() and doexecute() need it now.
(doredir, dopipe, doexecute): Use new seen_input() instead of gettag().
(doexecute): Set input_fd and leave reading the script file to play().
(serverio, termio, sendeof): Replaced by play(), remove.
(LBUF_LEN_MAX, lbuf, lbuf_init, lbuf_len, lbuf_full, lbuf_line)
(lbuf_putc): New.
(RING_SIZE, ring, ring_init, ring_len, ring_space, ring_peek)
(ring_getc, ring_putc, ring_putm, ring_discard, ring_search)
(ring_from_file, ring_to_file): New.
(clear_recent_input, save_input, seen_input): New.
(MAX): New.
(ioqueue, io, ioq_init, ioq_dequeue, ioq_read, ioq_write, ioq_qsize)
(ioq_drain, ioq_gets, ioqtobuf, enqueuecc, dequeuecc): Unused, remove.
(QEMPTY, qelem, insque, remque, initque): Unused, remove.
(tagstruct, taglist, io_init, gettag): Unused, remove.
